VOLUME 2 - WRAPAir.org...2005/11/18 · Engine Rebuild Engine Maintenance and Repair The material contained in Volume 2 will be updated periodically as new information becomes available

VOLUME 2 WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

November 18, 2005

VOLUME 2

RETROFIT TECHNOLOGIES, APPLICATIONS AND EXPERIENCE

Emissions Advantage, LLC 1717 Pennsylvania Ave., NW, Suite 650 Washington, DC 20006

©2005 Emissions Advantage, LLC November 18, 2005


TABLE OF CONTENTS VOLUME 2– RETROFIT TECHNOLOGIES, APPLICATIONS AND

EXPERIENCE I. INTRODUCTION........................................................................................................2.I-1 II. DIESEL OXIDATION CATALYST........................................................................ 2.II-1 A. Technology Overview and Description ........................................................... 2.II-1

B. Emission Reduction ......................................................................................... 2.II-2

C. Status and Availability..................................................................................... 2.II-3

D. Selection and Use Criteria ............................................................................... 2.II-4 E. Installation and Vehicle Modifications............................................................ 2.II-5 F. Fuel Requirements ........................................................................................... 2.II-7 G. Maintenance..................................................................................................... 2.II-7 H. Costs................................................................................................................. 2.II-7 III. DIESEL PARTICULATE FILTER ........................................................................ 2.III-1 A. Technology Overview and Description .......................................................... 2.III-1

B. Emission Reduction ........................................................................................ 2.III-8

C. Status and Availability.................................................................................... 2.III-9

D. Selection and Use Criteria ............................................................................ 2.III-11 E. Installation and Vehicle Modifications......................................................... 2.III-14 F. Fuel Requirements ........................................................................................ 2.III-16 G. Maintenance.................................................................................................. 2.III-17 H. Costs.............................................................................................................. 2.III-19

©2005 Emissions Advantage, LLC 2-i November 18, 2005


IV. LEAN NOx CATALYST..........................................................................................2.IV-1 A. Technology Overview and Description ..........................................................2.IV-1

B. Emission Reduction ........................................................................................2.IV-2

C. Status and Availability....................................................................................2.IV-2

D. Selection and Use Criteria ..............................................................................2.IV-3 E. Installation and Vehicle Modifications...........................................................2.IV-4 F. Fuel Requirements ..........................................................................................2.IV-4 G. Maintenance....................................................................................................2.IV-4 H. Costs................................................................................................................2.IV-4 V. SELECTIVE CATALYTIC REDUCTION ............................................................ 2.V-1 A. Technology Overview and Description ........................................................... 2.V-1

B. Emission Reduction ......................................................................................... 2.V-2

C. Status and Availability..................................................................................... 2.V-3

D. Selection and Use Criteria ............................................................................... 2.V-3 E. Installation and Vehicle Modifications............................................................ 2.V-4 F. Fuel Requirements ........................................................................................... 2.V-5 G. Maintenance..................................................................................................... 2.V-6 H. Costs................................................................................................................. 2.V-6 VI. SELECTIVE NON-CATALYTIC REDUCTION .................................................2.VI-1 VII. LOW PRESSURE EXHAUST GAS RECIRCULATION ...................................2.VII-1 A. Technology Overview and Description .........................................................2.VII-1

B. Emission Reduction .......................................................................................2.VII-2

C. Status and Availability...................................................................................2.VII-3

D. Selection and Use Criteria .............................................................................2.VII-3

©2005 Emissions Advantage, LLC 2-ii November 18, 2005


E. Installation and Vehicle Modifications..........................................................2.VII-3 F. Fuel Requirements .........................................................................................2.VII-4 G. Maintenance...................................................................................................2.VII-4 H. Costs...............................................................................................................2.VII-4 VIII. CLOSED CRANKCASE VENTILATION EMISSION CONTROL ............... 2.VIII-1 A. Technology Overview and Description ....................................................... 2.VIII-1

B. Emission Reduction ..................................................................................... 2.VIII-2

C. Status and Availability................................................................................. 2.VIII-3

D. Selection and Use Criteria ........................................................................... 2.VIII-3 E. Installation and Vehicle Modifications........................................................ 2.VIII-3 F. Fuel Requirements ....................................................................................... 2.VIII-4 G. Maintenance................................................................................................. 2.VIII-4 H. Costs............................................................................................................. 2.VIII-4 IX. ENGINE ELECTRONIC CONTROL MODULE REPROGRAM .....................2.IX-1 A. Technology Overview and Description ..........................................................2.IX-1

B. Emission Reduction ........................................................................................2.IX-1

C. Status and Availability....................................................................................2.IX-2

D. Selection and Use Criteria ..............................................................................2.IX-3 E. Installation and Vehicle Modifications...........................................................2.IX-3 F. Fuel Requirements ..........................................................................................2.IX-3 G. Maintenance....................................................................................................2.IX-3 H. Costs................................................................................................................2.IX-3

©2005 Emissions Advantage, LLC 2-iii November 18, 2005


X. ULTRA-LOW SULFUR DIESEL FUEL ................................................................ 2.X-1 A. Product Overview and Description.................................................................. 2.X-1

B. Emission Reduction ......................................................................................... 2.X-1

C. Status and Availability..................................................................................... 2.X-1

D. Selection and Use Criteria ............................................................................... 2.X-1 E. Costs................................................................................................................. 2.X-2 F. Product Quality, Delivery, Storage and Fueling.............................................. 2.X-2 XI. BIODIESEL...............................................................................................................2.XI-1 A. Product Overview and Description.................................................................2.XI-1

B. Emission Reduction ........................................................................................2.XI-2

C. Status and Availability....................................................................................2.XI-2

D. Selection and Use Criteria ..............................................................................2.XI-4 E. Costs................................................................................................................2.XI-4 F. Product Quality, Delivery, Storage and Fueling.............................................2.XI-5 XII. DIESEL FUEL EMULSIONS ................................................................................2.XII-1 A. Product Overview and Description................................................................2.XII-1

B. Emission Reduction .......................................................................................2.XII-1

C. Status and Availability...................................................................................2.XII-1

D. Selection and Use Criteria .............................................................................2.XII-2 E. Costs...............................................................................................................2.XII-2 F. Product Quality, Delivery, Storage and Fueling............................................2.XII-2 XIII. DIESEL FUEL ADDITIVES ................................................................................ 2.XIII-1 A. Product Overview and Description.............................................................. 2.XIII-1

B. Emission Reduction ..................................................................................... 2.XIII-1

©2005 Emissions Advantage, LLC 2-iv November 18, 2005


C. Status and Availability................................................................................. 2.XIII-2

D. Selection and Use Criteria ........................................................................... 2.XIII-2 E. Costs............................................................................................................. 2.XIII-2 F. Product Quality, Delivery, Storage and Fueling.......................................... 2.XIII-2 XIV. OPERATIONS-BASED STRATEGIES .............................................................. 2.XIV-1 A. Idle Reduction.............................................................................................. 2.XIV-1 B. Engine Repower......................................................................................... 2.XIV-12 C. Vehicle/Equipment Replacement............................................................... 2.XIV-16 D. Engine Rebuild........................................................................................... 2.XIV-18 E. Maintenance and Repair ............................................................................ 2.XIV-20 XV. VOLUME II REFERENCES AND BIBLIOGRAPHY ...................................... 2.XV-1

©2005 Emissions Advantage, LLC 2-v November 18, 2005

VOLUME 2 – Section I WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

I. INTRODUCTION Volume 2 contains a description of retrofit technologies and related issues in choosing and using them. This volume provides detailed background information to supplement the technology discussions in Volume 1. The information provided is designed to serve as a reference tool for air quality management and others, and to provide potential product users with a basic introduction to retrofit technologies and the current information available on their use. As used in this volume, the “retrofit technologies” refer to both hardware- and fuel-based strategies, as well as operations-based strategies. The retrofit technologies are shown in Table 1-1.

Table 1-1, Strategies for Reducing Emissions from Offroad Diesel Engines

Technology-Based Strategies Diesel Oxidation Catalyst (DOC) Diesel Particulate Filter (DPF) Lean NOx Catalyst (LNC) Selective Catalytic Reduction (SCR) Selective Non-catalytic Reduction (SNCR) Low Pressure Exhaust Gas Recirculation (EGR) Closed Crankcase Ventilation (CCV) systems Engine Electronic Control Module (ECM) Reprogram

Fuel-Based Strategies Ultra-low Sulfur Diesel (ULSD) Fuel Biodiesel Diesel Fuel Emulsions Diesel Fuel Additives

Operations-Based Strategies Idle Reduction Engine Repower Early Retirement of Equipment Engine Rebuild Engine Maintenance and Repair

The material contained in Volume 2 will be updated periodically as new information

becomes available.

©2005 Emissions Advantage, LLC 2.I-1 November 18, 2005

VOLUME 2 – Section II WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

II. DIESEL OXIDATION CATALYST (DOC) A. Technology Overview and Description

OVERVIEW

DOCs have been in commercial use since the late 1960s in offroad applications and since

the 1980s in on-road applications. This technology has a proven track record of excellent performance. In on-road OE applications, over 50 million passenger cars and over 3 million trucks and buses have been equipped with DOCs. Worldwide, over 200,000 trucks and buses have been retrofitted with DOCs. In addition, over 250,000 new and existing offroad engines have been equipped. DOCs have the greatest application experience of any retrofit strategy, having been installed on trucks, buses, passenger cars, and offroad equipment including mining equipment, construction equipment, utility equipment, locomotives and marine vessels. Retrofitting engines with DOCs is extremely popular since the technology has near universal application. It is easily installed, requires virtually no maintenance, does not adversely impact vehicle performance or fuel consumption, achieves emission reductions in a cost-effective manner, and can operate effectively on fuels with 500 ppm sulfur and higher depending on the application and the pollutant(s) to be controlled.

DOCs control PM exhaust emissions by 20% to 50% depending on the engine exhaust

temperature, the sulfur level in the fuel, the composition of the engine-out PM, and other factors. This technology also controls HC and CO up to 90%, as well as reducing diesel smoke and virtually eliminating diesel odor. Also, in cases where DOCs are used as a muffler replacement, the noise attenuation of the DOCs meets or exceeds the specification of the OE muffler being replaced. DOCs in both on-road and offroad applications have demonstrated high emission reduction performance over extended periods. DOCs routinely last the remaining life of the engine. Problems with DOCs have been very rare. Where they have occurred, they tended to involve such issues as improper DOC design configuration for a particular vehicle/equipment application or failure to provide the correct installation hardware. These types of issues can be easily addressed by close coordination and planning between the DOC supplier and the vehicle/equipment fleet personnel. DOC plugging has occurred on very rare occasions and typically involved older (pre-1990), high oil consumption engines that may operate at idle for expended periods of time and/or operate in areas with very cold ambient temperatures. Potential problem vehicles can be rejected for DOC retrofit, engines can be rebuilt, or the vehicle/equipment repowered. Also, backpressure monitors can be installed if there is a risk of PM accumulating on the catalyst substrate leading to engine backpressure increase.

Decades of experience indicate that DOCs do not have any adverse impacts on engine performance. With regard to fuel economy, studies conducted over the years generally have reported that either DOCs have no impact on fuel economy or in those cases in which a slight decrease was measured, it was not statistically significant.

Several DOC designs have been verified by EPA and CARB for on-road and to a limited extent for offroad applications (see www.epa.gov/otaq/retrofit/retroverifiedlist.htm, and

©2005 Emissions Advantage, LLC 2.II-1 November 18, 2005


www.arb.ca.gov/diesel/verdev/verdev.htm). The PM soluble organic fraction (SOF) from a diesel engine is related, in part, to the engine lubricant consumption and in-cylinder combustion characteristics of that diesel engine. DOCs can be used in combination with other technologies including, FBCs, DPFs, LNCs, SCR and CCV systems. DOCs also have been used in combination with engine modification kits that reduce NOx emissions. This latter technology combination was used, for example, in the EPA urban bus retrofit/rebuild program in the early 1990s.

The overall experience with DOCs in retrofit applications during the past 30 years has been outstanding. This technology has been the most popular retrofit choice to date because of several factors including:

• Virtually universal application. • Easy installation.

• No technology maintenance.

• Ability to be used on vehicles/equipment fueled with conventional diesel fuels.

• Lower cost compared to other retrofit technologies.

• No operational issues, impacts on vehicle/equipment performance or impacts on fuel

consumption. TECHNOLOGY DESCRIPTION

A typical DOC is a stainless steel canister installed in the exhaust system much like a

muffler. The canister contains a catalyst support or “substrate” on which the catalytic material is coated. These substrates are typically ceramic or metallic honeycomb-shaped or, in some cases, wire mesh. The substrate is coated with a catalytic formulation, which includes precious metals such as platinum and palladium. There are no moving parts, just a large amount of surface area coated with the catalytic formulation. As the exhaust gas passes through the substrate, the SOF, CO, and HC are chemically oxidized to form CO2 and water. In some instances, PM exhaust emissions of a vehicle/equipment are extremely high, as can occasionally be an issue with some larger, older offroad engine. In those cases where high levels of PM are emitted and there is some concern that the DOC could plug, a backpressure monitor can be installed. Figure 2-1 is an example of a commercially available muffler replacement-style DOC for retrofit applications.



Figure 2-1, Muffler Replacement DOC

B. Emission Reduction

A DOC reduces engine-out unburned HCs, toxic HCs CO by up to 90%, and exhaust PM by 20% to 50% depending on exhaust temperature, sulfur level in the fuel, composition of engine-out PM and other factors. DOCs control the SOF of the PM by up to 90%. The PM SOF from a diesel engine is related, in part, to the engine lubricant consumption and in-cylinder combustion characteristics of that diesel engine. Older engines with higher lubricating oil consumption typically emit a high fraction of SOF and as a result the DOC will reduce a greater percent of total PM than would be achieved on a newer engine with a lower percentage of SOF. Older offroad engines typically have a higher concentration of SOF compared to new on-road vehicles, making DOCs a particularly effective application for these offroad engines. Since DOC technology is designed to control the SOF of the PM, the technology is not effective in reducing the carbon-based particles, including the ultra-fine fraction. DOCs do not impact the level of NOx emissions and, since DOCs typically do not adversely impact fuel consumption, they do not affect the level of CO2 emissions.

DOCs also reduce smoke emissions from older vehicles by over 50% and virtually

eliminate the pungent odor associated with diesel engines. Also, the noise attenuation achieved by a DOC is equal to, and some cases exceeds, the performance of the OE muffler may replace.

DOC performance is not reduced significantly when used with conventional low sulfur

content (up to 300 ppm to 500 ppm) diesel fuel. However, the amount of sulfate, and in turn the amount of total PM measured will increase as the sulfur content increases. Consequently, the emission control performance of a DOC is enhanced if it is operated with ultra-low sulfur diesel fuel (ULSD) with a maximum sulfur content of 15 ppm.

C. Status and Availability

Commercial application of DOC technology has spanned over 30 years. The technology has been successful applied and operated extremely effectively on a broad range of on-road and offroad applications. As noted above, with on-road OE applications over 50 million passenger cars in Europe and over 3 million trucks and buses in the U.S. alone have been equipped with DOCs. Worldwide, over 200,000 trucks and buses have been retrofitted with DOCs. DOC retrofit kits for passenger cars have been commercially available since the early 1990s. In addition, over 250,000 new and existing offroad engines have been equipped with DOCs.



ON-ROAD VEHICLE DOC RETROFIT STATUS

Numerous DOC retrofit projects have been conducted throughout the world involving

trucks and buses. For example, Hong Kong has implemented DOC retrofit programs involving 40,000 medium duty trucks and 2,000 transit buses. In Mexico, over 8,000 heavy-duty vehicles were retrofitted with DOCs. Under the U.S. EPA urban bus retrofit/rebuild program, over 15,000 transit buses were retrofitted with DOCs. In the U.S. over 250 individual school districts have implemented or will soon implement DOC retrofits on school buses. Other U. S. programs currently underway are applying DOC retrofits to school buses, transit buses, freight and delivery vehicles, refuse trucks and utility vehicles. OFFROAD EQUIPMENT DOC RETROFIT STATUS

As noted above, DOCs have been retrofitted on offroad equipment for over 30 years and

this technology has been equipped on over 250,000 offroad engines. The types of offroad equipment retrofitted with DOCs includes mining equipment (e.g., excavators), construction equipment (e.g., skid steer loaders, dump trucks, rubber tire loaders, excavators), materials handling equipment (e.g., forklifts), utility equipment (e.g., street sweepers, tractors), agricultural equipment (e.g., irrigation pumps), and marine vessels (e.g., passenger ferries). DOCs have been used on offroad engines ranging from less than 75 hp (e.g., forklifts) to over 750 hp (e.g., large passenger ferries in Hong Kong and large stationary engines in California).

Two U.S. programs involving larger scale DOC retrofit on offroad equipment are the

Massachusetts Central Artery/Tunnel Project (the “Big Dig” project) in Boston, Massachusetts and the I-95 New Haven Harbor Crossing Corridor Improvement Program (Q-Bridge Project) in New Haven, Connecticut (See Volume 1, Section III.B. for more information about these programs). Over 200 pieces of construction equipment were retrofitted with DOCs as part of the Big Dig project and nearly 100 DOC retrofits on construction equipment on the Q Bridge project.

AVAILABILTY

Retrofit DOCs are readily available from several technology and product suppliers. Appendix D contains a list of suppliers. As noted previously, products are available in a variety of engine size ranges and configurations, including muffler replacements and add-on products. Custom-configured units can also be provided by several suppliers.



D. Selection and Use Criteria

With very limited exceptions, DOC technology can be applied to virtually any type and

size of diesel-powered engines. As noted above, DOCs have been applied to a wide range of on-road and offroad diesel engine applications. The only potentially limiting factors are 1) available space on the vehicle or equipment, 2) older engines with extremely high PM emissions levels (e.g., pre-1990 model year), 3) very cold exhaust temperatures (below 200°C such as were vehicles/equipment operate in extremely cold ambient temperature conditions and idle for extended periods), and 4) vehicles that operate on diesel fuels with substantially higher than 500 ppm sulfur levels. AVAILABLE SPACE

In almost every instance in which a DOC retrofit was contemplated, available space was found to equip the technology. However, it is possible that situations will arise where the available space is not sufficient to insure proper installation and performance of the DOC or to avoid interference with vehicle/equipment operation. For that reason and in those rare applications where available space may be an issue, an inspection of the vehicle/equipment by the technology provider and coordination between the technology provider, the vehicle/ equipment operator, and, where appropriate, knowledgeable staff of the engine manufacturer distributor. HIGH PM EMITTING VEHICLES/EQUIPMENT

If the engine-out PM is too great, it possibly could plug the DOC. This rarely has been

an issue, but it can occur with older, high-oil consumption engines (e.g., two-stroke engines), particularly on engines with large horsepower ratings. For example, a DOC installed on an older locomotive with a two-stoke, 3,000 hp engine that had high-oil consumption and was operated at idle for extended periods plugged the DOC in a matter of weeks. Where extremely high PM emissions are an issue, it may be best to reject the applications or to have the vehicle/equipment repowered. Also, DOCs with large substrate cell sizes can be utilized to reduce the impacts of higher PM emissions. Where there is concern about PM build-up on the surfaces of the DOC substrate, backpressure monitors can be installed.

EXTREMELY LOW EXHAUST TEMPERATURES

To function properly, a DOC needs exhaust temperatures that are above 200°C. On rare

occasions, problems have occurred with the failure to achieve the minimum temperatures needed for the DOC to function effectively. This problem has occurred in the past on occasion when a vehicle is operated in very could climates (e.g., Alaska during the winter) and the vehicle/equipment idled for extended periods (e.g., up to two days). If any question exists regarding whether the vehicle/equipment may not achieve adequate exhaust temperature, temperature traces can be measure over the expected operating cycle under the worst ambient temperatures expected. Also, insulation can be installed in the exhaust system upstream of the DOC to help retain exhaust temperatures reaching the DOC.



E. Installation and Vehicle Modifications As noted above, DOC technology has virtually universal application, installation typically is very straight-forward and maintenance is rarely, if ever required. Nevertheless, care should be taken in: 1) selecting and preparing vehicles/equipment for retrofit, 2) installing the DOCs, and 3) periodically checking the DOC, the installation hardware and the exhaust system for physical damage. PRE-INSTALLATION PROCEDURES Even though DOCs can be readily retrofitted on virtually all types of vehicles and equipment, a screening process should be conducted. First, it should be determined whether the vehicle is already equipped with a DOC. All transit buses sold beginning with the 1994 model year were equipped with DOCs and certain light and heavy-duty trucks and school buses have DOCs installed as original equipment. Unfortunately, a comprehensive list of engine/vehicle models does not exist, nor will a visual examination of the exhaust system always provide an answer. The technology supplier may have some information, but the best way to determine is to check the muffler part number. If it is an OE DOC/muffler it will have a special part number.

Vehicle/equipment with engines that have excessively high lubricating oil consumption, have a history of mechanical problems, or are nearing retirement are not good candidates for DOC retrofit. Also, vehicles/equipment with very low operating temperatures such as those that will operate at idle for very long periods and/or operate in extremely cold ambient temperatures may not be good candidates.

Prior to installation, both the engine and exhaust system should be inspected for any worn

parts or leaks. Any routine or necessary maintenance should then be performed. Performing needed maintenance not only will prepare the engine for DOC retrofit, but it could also improve fuel economy and vehicle/equipment performance.

INSTALLATION AND VEHICLE MODIFICATIONS

DOC installation is very straightforward and most often the DOC is installed as a direct replacement for the existing OE muffler. Installation typically takes one to two hours and is often performed by fleet personnel. At least some training by the DOC provider is beneficial. The DOC can also be installed as a direct fit in the exhaust system, including as a direct fit close-coupled to the manifold. For direct fit applications, the retrofit installation is frequently performed by, or in close consultation with, the DOC supplier.

Muffler designs and the length of inlet and outlet exhaust pipes can vary greatly. Given

the breadth of experience with DOC retrofits, the DOC provider in many cases will have pre-fabricated DOC/piping designs available. In those instances where prefabricated designs are not available, the technology provider should inspect the vehicles or in some other manner (e.g., scale drawings) obtain the necessary information on the dimensions and connecting piping to ensure a proper retrofit. The retrofit kit should also contain the appropriate installation hardware (e.g., hangers) or, at the least, instruction regarding the appropriate installation hardware that should be used by the vehicle/equipment fleet personnel.



Over the past several years, delays in DOC deliveries, often substantial at times, have

been experience in the U.S. due to industry-wide shortages of catalyst substrates. This shortage was caused by a rapid increase in demand worldwide for both DOC substrates and DPF filters. The supply shortage seems to be improving and increased manufacturing capacity has been brought on line. Nevertheless, the possibility of delays should be factored into plans to meet retrofit project schedules – the more lead time allowed for delivery, the greater the chance the retrofits can be completed on schedule. F. Fuel Requirements

While maximum DOC performance can be achieved with diesel fuel containing less than 15 ppm sulfur, DOCs have performed effectively on vehicles/equipment fueled with diesel fuel up to 500 ppm sulfur content. DOCs have also been installed on vehicles/equipment that contain more than 500 ppm sulfur content. DOC performance on fuels with a higher sulfur content will vary depending on the catalyst formulation, engine type, and duty cycle. In cases in which the goal is to reduce PM, as opposed to HC or CO, diesel fuel with less than 500 ppm sulfur content is recommended. G. Maintenance

As noted above, DOCs typically do not require any maintenance. Nevertheless, the DOC, the installation hardware and the exhaust system should be visually inspected periodically for physical damage or deterioration. In situations in which there has been an engine malfunction, such as faulty injectors or the vehicle/equipment emits high levels of PM, it is advisable to determine if catalyst substrate plugging is occurring. In those extremely rare instances in which ash and other materials accumulate on the surfaces of the DOC substrate causing an engine backpressure increase, the DOC can be removed and cleaned using methods like those employed in cleaning DPFs (See Volume 2, Section III). H. Costs

In 2000, CARB estimated the expected cost of DOC technology by horsepower rating as

shown in Table 2-1 below.

Table 2-1, CARB-Estimated Costs of DOC Technology

Engine Horsepower Hardware Cost 40 $400 - $600 100 $680 - $1,356 275 $2,100 - $3,700 400 $2,800 - $3,700 1,400 $10,000 - $20,000

More recent estimates, suggest the costs for DOCs in retrofit applications are decreasing

slightly and range from less than $500 to $1,250 for engines in the 100-200 horsepower category, and from less than $1,000 to $1,750 for engines in the 200-500 horsepower category. Costs can vary



depending on such factors as: 1) whether the DOC was installed as a separate device (“direct fit”) in the engine exhaust or a muffler replacement and 2) the number of DOCs being purchased. The cost of DOC technology may continue to decline as the volume for DOC substrates (and DPF filters) increases providing economies of scale in production.

DOC installation typically takes one to two hours and if provided by the technology supplier

or its agent, the cost is in the range of less than $100 to about $200. Since, DOC installation is relatively straightforward, fleet technicians, sometimes after receiving training from the DOC supplier, install the DOCs themselves, thereby avoiding external installation costs. Finally, since DOCs are virtually maintenance free except for periodic checks of the DOC and exhaust system for mechanical integrity, typically no maintenance costs are incurred.


VOLUME 2 – Section III WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

III. DIESEL PARTICULATE FILTER (DPF)

A. Technology Overview and Description

OVERVIEW

DPFs are commercially available and used both as original equipment (OE) on passenger

cars in Europe and on transit buses in the U.S. and elsewhere. Also used as a retrofit technology, DPFs are found on a variety of on-road and offroad vehicles and equipment. DPFs have demonstrated the capability to reduce PM by up to 90% or more, and those DPFs that employ a catalyst component are capable of reducing HC and CO by up to 90%. DPFs also reduce or eliminate smoke and odor from a diesel engine. DPFs do not impact NOx emissions and most DPF designs have little or no measurable impact on fuel consumption. Overall, the performance record for DPFs has been quite good. Some technology and application-related problems and failures have arisen, but as application experience grows and improvements to the technology are made, the instances of problems continue to decline. A relatively new development is the emergence of flow-through filters that have a lower PM mass control efficiency compared to conventional DPFs, but have the potential for wider vehicle/equipment applications. DPF technology is application specific. This means that before the technology can be applied to a given vehicle or piece of equipment, certain prerequisites most be met. Considerable care is needed in determining whether a DPF is a good fit for a particular application (See “Selection and Use Criteria”, below). DPFs also require more maintenance and performance monitoring than other technologies such as DOCs. Several DPFs have been verified for on-road applications and limited offroad applications by both EPA and/or CARB (see www.epa.gov/otaq/tretrofit/retroverifiedlist.htm, and www.arb.ca.gov/diesel/verdev/verdev.htm). In retrofit applications, DPFs can be combined with NOx control technologies such as lean NOx catalysts, SCR technology and low-pressure EGR systems to provide significant PM and NOx emission reductions.

DPFs are often categorized as either “passive” or “active” depending on the method used to achieve filter regeneration. A passive DPF is one in which the filter regenerates in normal vehicle/equipment operation without any additional assistance. Examples of passive DPFs are filters coated with a catalytic material, a diesel oxidation catalyst upstream of the DPF, and a FBC used in combination of a filter. An active DPF system relies on additional strategies to ensure that filter regeneration occurs. Examples of active DPFs are ones that employ engine modifications, fuel injection, on-board burners or heaters, or off-board electrical heaters.

The advantages of passive systems are that they are technologically less complex, require far less servicing, and are less expensive than active systems. The advantage of active systems is that they will function effectively even if the desired exhaust temperatures are not achieved in normal operation and consequently can be employed in applications (e.g., vehicles/equipment with low exhaust temperatures) on which passive filters cannot used.

In the U.S., most retrofit applications have employed passive systems, while in Europe

both passive and active DPF systems have been widely used. Looking to the future, a combined

©2005 Emissions Advantage, LLC 2.III-1 November 18, 2005

http://www.epa.gov/cleandiesel


strategy of catalyst-based filters plus an active component such as fuel injection will be used to meet the EPA 2007 and later model year on-road heavy-duty truck standards. Catalyst-based filters with an active component could also emerge in retrofit applications.

The overall experience with both active and passive DPFs in both on-road and offroad

applications has been very good. When properly constructed, applied, maintained, and fueled, DPFs have demonstrated high PM control efficiencies for extended periods. For example, studies have reported that DPFs: 1) on trucks have performed effectively for up to 350,000 miles or more, 2) on offroad applications have performed effectively for up to 15,000 hours or more in rugged work environments, and 3) on locomotives have performed effectively for over 400,000 kilometers without any reported problems. In those instances were applications of passive DPFs were successful in terms of emission control performance, system durability, and minimum maintenance, several common factors were present, including:

• Newer, well-maintained engines with low engine lubricating oil consumption.

• Engines fueled with ULSD.

• Operating exhaust temperature profiles were well above the minimum time/temperature

specified by the technology provider. Occasionally, problems have arisen with DPF applications/operations but the instances of

problems have declined over time as experience has been gained in properly selecting applications for retrofit and DPF design improvements have been made. For example, the Switzerland construction equipment retrofit program was initiated in 1998 and resulted in over 7,000 engines being equipped with either active or passive DPFs. As a result, this program had a failure rate of only 2% in 2003 (down from 10% in 1998 and 6% in 2000). Program officials predict that in the near future the failure rate will drop well below 1%.

DPF problems and failures have occurred in both pilot and full-scale commercial

programs. In pilot programs, which typically are conducted to test and even “push” the limits of the technologies, applications and fuel sulfur levels, problems and failures are expected to be part of the process. In commercial applications, problems, where they have occurred can be traced to several recurring issues. The most frequent problem associated with DPF technology is the plugging of the filter with PM, which in some cases resulted in a filter failure. A secondary problem was the occasional malfunction of the backpressure alarm or the electronic diagnostic system. The causes of filter plugging/failure include the following:

• Inadequate exhaust temperatures to support filter regeneration. • Improper filter sizing for a specific application.

• Engine component wear or failure.

• Fueling with diesel fuel with too high a sulfur level.



• Incomplete filter cleaning. • DPFs that were installed on OE engines with high-pressure EGR systems.

Adequate Temperatures to Support Filter Regeneration – For passive DPF systems,

which depend on a minimum exhaust temperature profile for filter regeneration, the failure to achieve adequate temperatures in actual operation is the major cause of premature filter plugging, filter failures, and vehicle/equipment operational problems. Problems with filter plugging have occurred even when data logging was performed and the exhaust temperatures were consider adequate to support regeneration. In those cases, the problem can be traced to the fact that the vehicle/equipment operating cycle did not represent the “worst-case” operating cycle in terms of engine speed, engine load, and idling time.

Improper Filter Sizing – If the filter size in terms of volume is inadequate to properly

collect and destroy the PM as required, premature plugging can occur. This problem can be fixed by increasing the volume of the filter, typically by increasing the filter diameter. For example, a fleet of transit buses operating in Washington State experienced some problems with premature filter plugging. When the original filter, which had a diameter of 9 inches was replaced with a filter with a 10.5-inch diameter, the filter cleaning intervals were extended to once a year or longer. Of course, care must be taken to ensure a DPF with a larger filter volume can be properly fitted to the vehicle/equipment.

Engine Component Wear or Failure – Engine component wear or failure can cause

excess fuel or lubricating oil to be introduced into the engine combustion process resulting in excess PM created and collecting on the filter. This increased level of PM can result in the total amount of PM collected on the filter to exceed the capacity of the filter’s ability to destroy the PM. This in turn will cause premature filter plugging. For example, worn fuel injectors in some cases can drip enough fuel into the combustion chamber that the resulting increase in PM emissions can cause premature filter plugging. If a turbocharger failure occurs, it can very quickly result in filter plugging.

DPF Cleaning – Proper DPF cleaning can restore the filter to virtually the same or near

the same pressure drop through the filter. However, if the filter cleaning procedure is not performed correctly or is not the appropriate method given the nature of the constituents collected on the filter, residue will remain on the filter. As a result, the pressure drop through the filter will not be restored to original levels, and thus will shorten the interval until the next filter cleaning is required. For example, in some instances cleaning by using compressed air alone may not be sufficient to clean the filter. In those cases, the compressed air procedure should be used in combination with heat treatment.

Problems with OE High-Pressure EGR-Equipped Vehicles – Several transit bus projects in the U.S. have reported problems with OE DPFs equipped with high-pressure EGR systems on new engines . The problem is an issue of systems integration. Work is underway to better understand the causes of the problems and to develop appropriate technological fixes.

Using Diesel Fuel with Inappropriate Sulfur Levels – The sulfur level in diesel fuel can adversely impact the performance of catalyst-based DPFs. This includes adversely impacting the



filter regeneration process that can lead to filter plugging. Catalyst-based DPFs operate most effectively with ULSD (less than 15 ppm sulfur) although this technology has been applied occasionally in applications where the fuel had a sulfur content of less than 30 ppm and in rarer instances where the sulfur content was less than 50 ppm. Fuel sulfur-related problems can occur under several situations where: 1) vehicles/equipment are intentionally or inadvertently fueled with diesel fuel containing higher than recommended levels, 2) the fuel is contaminated during the delivery process or in the storage facilities, or 3) the fuel sulfur levels recommended by the technology provider proved to be too high to support proper filter regeneration.

On occasion, vehicle use or service has been interrupted because of malfunctions of the

exhaust backpressure sensor, the exhaust temperature thermocouple and/or the control software module which signaled a problem when no problem actually existed. These malfunctions have been attributed to such things as the sensitivity of the backpressure measurement probes and the need to better optimize the diagnostic systems to operate effectively in a given vehicle/ equipment operating application. The technology providers have developed improved systems to address these issues.

As experience with DPFs has grown, knowledge has been gained regarding better

application of the technology. This includes more informed decisions regarding the appropriate vehicle/equipment candidates for a DPF retrofit, including improved predictive capability modeling. It also includes using better application designs, including appropriate filter sizing and where needed, using insulation on the exhaust pipe between the engine and the inlet of the DPF, and/or around the DPF itself.

In addition, technological improvements have been made to the DPF system design to

reduce the possibility of problems. These include:

• Improvements to catalyst-based DPF system designs and catalytic formulas to initiate filter regeneration at lower operating temperatures.

• Improvements in the catalytic formulations of catalyst-based DPFs to make them less

sensitive in creating sulfates.

• Improvements in filter designs to be more resistant to ash build-up.

• Improved monitoring and diagnostic systems.

• Improved filter cleaning methods. The principal adverse impact from DPF application has been those instances in which the

DPF prematurely plugged and in some cases suffered a failure because the system failed to regenerate or clean the filter properly. The principal cause of filter plugging was the failure to reach the exhaust temperatures needed to help initiate proper filter regeneration. The build-up of PM on the filter causes the engine backpressure to increase to a point where engine performance is adversely affected (e.g., loss of power) or the vehicle must be taken out of service to remove, clean (or replace) and reinstall the filter.



Reports in the literature generally agree that passive catalyst-based DPFs have either no

measurable or only a slight impact on fuel economy. Often the difference reported is not statistically significant. DPFs using fuel combustion as a regeneration strategy will impact fuel economy. One study reported that a DPF using a fuel burner regeneration strategy had a fuel economy penalty of less than 2%. Catalyst-based DPFs do require the use of ULSD. Diesel fuel with less than 15 ppm sulfur has a lower energy content than conventional diesel fuel that translates into a slight fuel economy penalty (See “Ultra-Low Sulfur Diesel Fuel”, below). TECHNOLOGY DESCRIPTION

The DPF system consists of a filter encased in a stainless steel canister that is positioned

in the exhaust stream and is designed to collect particulate emissions while allowing the exhaust gases to pass through the system as shown in Figure 3-1. A DPF system has three main components: 1) the filter that collects or “traps” the PM, 2) a means for removing the PM from the filter or a “filter regeneration strategy” and 3) a mechanism for determining whether engine back pressure is increasing due to the build-up of ash and other constituents on the filter surfaces. These three components are discussed below.

Figure 3-1, Typical Muffler-Replacement DPF Construction

Courtesy of Fleeguard

A number of filter materials have been used in diesel particulate filters, including ceramic

and silicon carbide materials, fiber wound cartridges, knitted silica fiber coils, wire mesh, and sintered metals. Filter materials can be designed for varying levels of PM control ranging from less than 60% to greater than 90%. Currently, the most prevalently used filter materials in both OE and retrofit applications are ceramic cordierite and silicon carbide. An illustration of a ceramic wall-flow monolith is shown in Figure 3-2.



Figure 3-2, Example of Ceramic Wall-Flow Monolith

Courtesy of NGK

Since the volume of PM generated by a diesel engine is sufficient to fill up and plug a

reasonably sized filter in a relatively short time, some means of disposing the collected PM must be provided. The most promising means of disposal is to burn or “oxidize” the PM in the filter, thus regenerating or cleansing the filter. Since the diesel engine-out exhaust temperatures are not always sufficient to burn the PM, a strategy to generate sufficient temperatures is typically needed. Achieving the temperatures needed for regeneration can be attained in a variety of ways, including:

• Catalyst-based regeneration using a catalyst applied on the filter surface – A base or precious metal coating applied on the filter surface reduces the ignition temperature necessary to oxidize the accumulated PM.

• Catalyst-based regeneration using an upstream oxidation catalyst – An oxidation

catalyst is placed upstream of the filter to facilitate oxidation of nitric oxide (NO) to nitrogen dioxide (NO2). The nitrogen dioxide adsorbs on the collected particulate substantially reducing the temperature required to regenerate the filter. This strategy has been employed in combination with both an uncatalyzed and catalyzed filter.

• Fuel-borne catalysts – Precious and base metal additives are added to the fuel to reduce

the temperature required to regenerate the filter.

• Air-intake throttling – Throttling the air intake to one or more of the engine cylinders can increase the exhaust temperature and facilitate filter regeneration.

• Post top-dead-center (TDC) fuel injection – Injecting small amounts of fuel in the

cylinders of a diesel engine after the pistons have reached TDC introduces a small amount of unburned fuel in the engine’s exhaust gases. This unburned fuel can then be oxidized in the DPF to combust accumulated PM.

• On-board fuel burners or electrical heaters – Fuel burners or electrical heaters upstream

of the filter can provide sufficient exhaust temperatures to ignite accumulated PM and regenerate the filter. In some cases the fuel is injected over a DOC.

• Off-board electrical heaters – Off-board filter regeneration stations combust trapped PM

by blowing hot air through the filter system. This filter regeneration technique can be



performed with the filter still installed on the vehicle/equipment or by removing the filter and connecting it to the cleaning station.

A backpressure monitor/alarm component is a critical part of a DPF system. If the DPF

is not effectively destroying all of the PM collected on the filter during normal engine operation, PM (ash and other constituents) will build up over time on the surfaces of the filter. If there is an engine problem (worn fuel injectors or turbocharger failure) that results in elevated levels of PM entering the filter, the PM build-up will occur far more rapidly. Increased levels of PM on the DPF filter surfaces will result in increased backpressure. If the backpressure level increases are high enough, it could result in a DPF failure and/or adverse impact on vehicle/equipment performance and fuel economy. If the backpressure monitoring system shows a sudden drop in engine backpressure, the cause may be a mechanical failure of the filter such as cracks or attrition. If the backpressure drops, the filter should be inspected.

A back pressure monitor/alarm system (see Figure 3-3 for example) tracks the backpressure levels, and warns the vehicle/equipment operator or technician that a problem exists before significant problems occur. It can also be used to help plan for and schedule filter cleaning. A variety of backpressure monitors exist using both audible and visual alarms to signal elevated backpressure levels. A popular alarm system employs a two-light (yellow/red) approach in which the yellow light is illuminated to signal that the backpressure has reach a level at which the DPF should be checked and cleaned as soon as possible and the red light is illuminated to signal that backpressure has reached a level that vehicle/equipment operation should cease. Some DPF systems are designed to have the engine’s electronic control system adjusted to allow the engine to allow the engine to operate in a low power mode when the red light is illuminated so that the vehicle operating in “limp mode” can return to the fleet yard. Alarm settings can be customized for each application.

Figure 3-3, Example of Back Pressure Monitor/Alarm System

Courtesy of MECA

Alarms are typically installed in view of the vehicle/equipment operator (typically on the

dashboard) on the or in the engine compartment. The advantage of an alarm visible to the operator is that the operator can take corrective action immediately. The disadvantage is that if the light(s) illuminate due to an alarm system malfunction and not because of a real backpressure issue, the operator may be distracted or take action such as removing the vehicle/equipment from service when such action is unnecessary. When the alarm is placed in the engine component, it



can be checked at the end of each shift by maintenance personal and if a light is illuminated, the backpressure and possible other causes (e.g., alarm sensor malfunction) for the illuminated light can checked.

Monitoring devices can range from a simple backpressure check to more sophisticated strategies that have a diagnostic and programming module that records not only backpressure, but information such as the history of control parameter settings, operating hours, and exhaust temperature as well. These systems not only alert the operator/technician to possible backpressure problems, but also provide data that can help identify the source of problems with either the DPF or engine components that can be addressed, subsequently.

Other types of DPF systems include: Disposable Filters -- In select offroad applications, a disposable filter system has been

used. The disposable filter is designed to collect the amount of PM that is likely to be generated during a working shift or two of operation while remaining within the engine manufacturer’s backpressure specification. The filter is then removed and properly disposed.

Flow-through Filters -- A relatively new type of DPF system has emerged that does not

trap the PM like the conventional DPFs discussed above, but instead is designed to provide exhaust flow turbulence and increased PM residence time. Several different design types are emerging, including wire mesh filter, pertubated path metal foil filter, and others. As discussed below, these flow-through filters have achieved PM reductions of 40% to more than 65%. While these levels are well below the PM control levels achieved by the conventional DPFs (over 90% PM reduction), they do have a broader application than the conventional DPF. This technology also has been referred to “high-efficiency DOCs”, “partial flow DPFs”, “DPFs”, and “wire mesh DOCs”. One flow-through filter design has been verified by CARB as a Level 2 technology that achieves at least a 50% reduction in PM and another combining a wire mesh filter plus a FBC has been verified by EPA as achieving over 55% PM reduction. Another concept is being tested on a transit bus in Michigan. This technology is composed of three elements: a wire mesh filter media, an air pulsation system and a soot reclamation/incineration system. The wire mesh media consists of layers of various compactness augmented with screens of various mesh size. This system agglomerates sub-micron and nano-size PM into dendrites (collections of tiny particles that resemble the shape of a tree or snow flake). As these dendrites grow in size, they break off and are collected on additional filter screens. The wire mesh media is then regenerated through pulsation of compressed air and the PM is collected in a bag. B. Emission Reduction

DPF technology has demonstrated the capability to reduce total PM mass by 85% to over 90% in the exhaust of both on-road vehicles (e.g. transit buses, school buses, refuse trucks, line-haul trucks) and offroad equipment (e.g., construction, mining, and locomotives). DPFs have the capability of reducing total carbon-based particulates by over 99%, including the ultra-fine carbon particles. Flow-through filters have achieved PM reductions ranging 40% to more than 65%. DPFs employing a catalyst component (catalyst coating on filter, DOC in front of the DPF, or FBCs) can achieve up to a 90% reduction in HC (including toxic HCs such a PAHs, Nitro-PAHs, and benzene) and CO. DPFs also can be designed to reduce or eliminate diesel



smoke and odor. The actual level of reductions measured will vary based on the type of DPF technology, the engine make and model, the operating cycle, the emission test cycle, and the testing equipment. DPFs generally do not have an impact on total NOx emissions. One NOx-related issue has arisen with those DPFs designed to generate NO2 in order to facilitate the oxidation of PM. Studies have found that this type of DPF system design can increase the NO2 fraction of the total NOx emitted from the tailpipe. Studies have reported percentage increases of the NO2 fraction of the total NOx emitted ranging from 6% to approximately 35%. The varying degree of increased NO2 from these DPF systems may be attributable to specific design features, different type engines, mileage accumulation and other factors. Technology providers are making progress in developing strategies to minimize NO2 production, including improvements in system design and catalyst formulations.


Limited DPF retrofit demonstrations began in the 1980s, primarily on offroad applications such as mining equipment, and continued in the early 1990s, expanding to transit bus applications as well. In the late 1990s and early 2000s, the number of retrofit programs and vehicles/equipment retrofitted grew significantly. Today, well over 200,000 DPFs have been retrofitted on a growing variety of on-road vehicles and offroad equipment worldwide. In addition, a large number of new on-road vehicles have been and are scheduled to be equipped with DPFs as original equipment. The vast majority of the DPFs retrofitted on on-road vehicles have been catalyst-based passive filters, while offroad applications have included both active and passive systems. In new vehicle applications, DPF systems typically employ an engine-based active component combined in may cases with a catalyst-based strategy. Various flow-through filter designs have be introduced in retrofit applications for both on-road vehicles such as school and transit buses and offroad applications such as large construction cranes. The application of flow-through filters both as original equipment and in retrofit applications is expected to grow rapidly in the future.

STATUS OF DPFs INSTALLED AS ORIGINAL EQUIPMENT

Passenger Cars -- DPFs were introduced on new diesel passenger cars in Europe

beginning in 2000 and today approximately 1,000,000 DPF-equipped automobiles have been sold. To date, no performance issues have been reported. Peugeot (PSA) was the first manufacturer to introduce a DPF-equipped passenger car and its system combined a FBC, a DOC in front of the filter, advanced engine controls and high pressure common rail fuel injection for filter regeneration. Over time, the amount of FBC was reduced which in turn extended the time between filter cleanings. At least six other passenger car manufacturers are selling DPF-equipped vehicles based on the PSA system with some systems using FBCs and others using catalyzed filters. On-Road Heavy-Duty Engines -- A growing number of new transit buses are being sold with DPFs in Europe and the U.S. In the U.S., beginning with the 2007 model year all heavy-duty trucks and buses are expected to be equipped with DPFs to meet EPA’s 2007 on-road HDE PM standard of 0.01 g/bhp-hr. These DPFs systems are expected to be integrated with advanced



engine controls to insure filter regeneration under all operating conditions. DPFs are anticipated to be used to meet the more stringent standards being implemented in Japan beginning in 2005 and may be used in some instances to help meet HDE Euro 4 standards that also take effect this year. Offroad Engines -- Over 20,000 DPFs have been installed on either new or existing offroad engines. OE applications have focused on mining and materials handling equipment. Beginning in 2011, DPFs are expected to be used on a growing number of offroad engines as EPA’s Tier 4 Offroad Engine PM emissions standards are phased in over a multi-year period. STATUS OF DPFs INSTALLED AS A RETROFIT TECHNOLOGY

Passenger Cars – Until recently, retrofitting diesel passenger cars with DPFs was

virtually non-existent. Recently in Europe a flow-through filter concept using sintered metal foil became commercially available for selected passenger car models.

On-Road Heavy-Duty Engines -- As noted above, the vast majority of DPF retrofits have involved on-road vehicles. Vehicle applications include transit buses, school buses, freight and delivery trucks, refuse trucks, and utility vehicles such as dump trucks. Transit bus fleets in Sweden, Great Britain, France, the U.S. (including, California, New York, Washington State, and Washington, DC) and elsewhere have been retrofitted with DPFs. In the U.S. alone, over 80 individual fleets have retrofitted or are planning to retrofit vehicles or equipment with DPFs.

There are two very successful programs involving transit buses. The first is the Sweden

Clean Cities Program (see Vol. I, Section 6) in which over 4,000 transit buses are equipped with DPFs with some buses accumulating over 250,000 miles of service without any significant issues. The New York City Transit Authority is the second program, in which over 500 transit buses have been retrofitted and up to 3,800 total buses are planned to be retrofitted with DPFs. Other examples of successful programs include the New York City Department of Sanitation in which several hundred refuse trucks have been retrofitted with DPFs and the ARCO/BP demonstration involving DPF retrofits on school buses, transit buses, delivery trucks and refuse trucks. Tokyo has instituted an extensive retrofit program. To date, tens of thousands of vehicles have been retrofitted with DPFs.

Offroad Engines -- DPFs have been installed on offroad equipment since 1986 with applications including mining and tunneling equipment, construction equipment, skid steer loaders, forklift trucks, locomotives, and other vehicles. Germany, Austria and Switzerland have established mandatory requirements for DPFs to be installed on mining and tunneling equipment. Switzerland has expanded that requirement to construction equipment and by the end of 2004, over 7,000 engines had been retrofitted with either active or passive DPF systems. DPFs in offroad applications typically have been used on engines rated at several hundred horsepower, but they are also used on smaller engines under 75 horsepower. Over 10,000 systems have been installed on forklift trucks, primarily in Europe since the early 1990s. DPFs have been installed on construction equipment such as wheel loaders, back-up generators, cranes (flow-through filter) and dump trucks. Since the mid-1990s in Europe, DPFs have been installed in very large engines, including over 100 locomotives on engines powered at up to 2,000 horsepower. Recently, a DPF was installed on a 4,000 horsepower diesel locomotive in Germany. Also, large



stationary engines have been equipped in such places as California on engines in the range of 800 horsepower to 2,800 horsepower.

AVAILABILTY

DPFs are available from several manufacturers worldwide. All of the major catalyst suppliers have received EPA verification for their products for on-road applications, and at least one has now been verified for offroad use. D. Selection and Use Criteria

As noted above, DPF technology is an application specific technology. This means that

in some applications there may be factors that preclude a DPF technology from being used. In making a decision whether to use DPF technology in a particular engine application, the following criteria must be considered:

• The level of engine-out emission levels, including those from the engine lubricating oil. • The engine operating exhaust temperature profile.

• Available space to equip the DPF.

• The level of sulfur in the diesel fuel.

• For certain catalyst-based DPFs, the proper NOx/PM ratio in the exhaust must be

available. For flow-through filters, the application criteria vary based on the level of the PM control

efficiency. At the lower PM control efficiencies, this technology has a very wide application much like a DOC. At higher PM control efficiencies, the technology is applied on a case-by-case basis.



AVAILABLE SPACE

An important consideration in applying DPF technology is to ensure that adequate space is available on the vehicle/equipment to properly install the DPF. Making this determination involves several factors including that: 1) adequate space exists in the exhaust system to install the device at the appropriate place to provide optimum performance, 2) access exists to easily inspect and remove the DPF for cleaning, and 3) the DPF can be installed without adversely impacting the operation of the vehicle or impacting the safety of the operator.

Courtesy of MECA

Adequate space must exist in the exhaust system to properly locate the DPF. Since size of

the DPF is often larger than the muffler it replaces, available space may be a limitation. Even if it is possible to fit the DPF somewhere else in the exhaust, the distance from the engine to the DPF may be too great that by the time the exhaust reaches the DPF, the exhaust temperatures are too low to sustain filter regeneration. Finding available space on some applications, such as older locomotives, has proven particularly challenging. If the only available suitable location for the DPF requires considerable time and effort to reach (e.g., the engine must be removed to allow access to the DPF), such an application may not be suitable for DPF application since the DPF filters must be removed and cleaned periodically. Finally, the location of the DPF should not interfere with vehicle/equipment operation (e.g., increased size of DPF should not interfere with vehicle/equipment clearance or create a safety risk to the operator, such as impairing the operator’s view). In most applications, available space, accessibility, and impact on vehicle/equipment operation or operator safety have not been a problem, but these factors still should be assessed when considering a DPF. In some cases, they may prevent the use of DPFs. HIGH PM EMITTING VEHICLES/EQUIPMENT

If the level of engine-out PM emissions, including those from the engine lubricating oil are sufficiently high, the volume of PM reaching the DPF can overwhelm the ability of the DPF system to remove the PM collected in the filter before it accumulates and plugs the filter. High PM levels are a greater issue with passive DPF systems, but can be a factor in employing an active DPF system as well. High PM levels also can be an issue in applying higher efficiency flow-through filters. Therefore, older engines that were designed to meet emissions standards less stringent than those currently in place for both on-road and offroad engines and which often consume excessive lubricating oil are typically not good candidates for DPF applications. Two-



stroke engines are a particularly challenging application for DPFs although DPFs have been applied to a limited degree on both on-road and offroad two-stroke engines.

In the U.S., passive DPF retrofits on trucks and buses have focused on 1994 and later

model engines, with the significant majority of those engines being 2000 and later model year. For offroad applications, in which the use of active, external heat regeneration strategies can be employed, properly maintained engines dating back to the late 1980s have been retrofitted. Regardless of the age of the engine, it should be in proper working order, oil consumption should not be excessive, and worn engine parts such as fuel injectors should be replaced.

Flow-through filters have potentially broader applications than conventional passive

DPFs, but exhaust temperatures and engine out PM levels should still be considered in applying FTFs. EXTREMELY LOW EXHAUST TEMPERATURES

For those DPF systems, such as catalyst-based systems, the ability to properly destroy

PM in the filter is influenced by the engine exhaust temperature and can only be employed if the minimum temperature for a given period is achieved (temperature/time requirement). If the operating exhaust temperatures are too low to enable the passive system to regenerate, PM will accumulate in the filter increasing backpressure, eventually adversely affecting engine performance, and causing potential DPF failure.

The minimum operating exhaust temperature requirement is typically expressed in terms

of a specific minimum temperature (e.g. 250°C) for a specific percentage of the time the engine is operating (e.g. 40%) There is no one temperature/time minimum that can be applied to all passive DPFs systems for all applications. Rather, the required temperature/time minimum needed will vary based on the design of the DPF and the engine application. For example, a DPF system was recently verified by CARB as a Level 3 technology (minimum 85% PM reduction) for application on 1994 and later model year on-road engines when the exhaust temperature is at 210°C for at least 40% of the duty cycle. On the other hand, a study involving construction equipment found that DPF performance was poor when the equipment operated at exhaust temperatures in the range of 250°C. Over the past decade, DPF technology has shown continued improvement (e.g., improved catalyst formulations and filter designs) to expand the operating temperature window in which a passive DPF system will perform effectively. Flow-through filters also generally have a broader exhaust temperature operating window than conventional



passive DPF systems. In each instance that a DPF technology is being considered, the technology manufacturer should be consulted to determine the minimum temperature/time needed for the engine application being considered.

In assessing whether a DPF is a potential option for a given engine application, a

necessary step is to generate and record data (data logging) for the engine operating exhaust temperature profile over the expected duty cycle for that engine. In conducting the data logging procedures, two items are extremely important including: 1) where the temperature probe is placed in the exhaust, and 2) the operating cycle(s) on which the data logging is performed. First, the temperature probe should be installed in the exhaust as close as possible to the inlet of the DPF as possible. The data logging information will be less representative as the distance the probe is placed from the filter increases. If it is necessary to install the temperature probe a distance from the DPF, an adjustment to the data logging results should be made to account for the drop in exhaust temperature between the location of the temperature probe and the inlet of the exhaust. Second, data logging should include an assessment of the “worst-case operating scenario” in terms of low- or no-load operation, stop-and-go driving, time at idle, and when possible, the coldest ambient temperatures that likely to occur during the year.

Vehicles/equipment that operate at high-load for extended periods such as line-haul

trucks or road graders are typically good candidates for DPF retrofits, while vehicles/equipment that operate with low loads and/or operate at idle for extended periods may not be suitable. A proper determination can be made for any application only if accurate and representative data logging is performed. For that reason, while fleet operators or others can perform data logging to preliminarily screen candidate vehicles/equipment, the technology provider should conduct its own data logging to confirm that its DPF technology is suitable for the engine application in question. LEVEL OF SULFUR IN DIESEL FUEL

See F. Fuel Requirements below. PROPER NOx/PM RATIO IN THE EXHAUST For a catalyst-based DPF that uses the conversion of NO to NO2 to facilitate the catalytic regeneration of the filter, the proper ratio of NOx to PM in the engine-out exhaust is needed. When considering a catalyst-based DPF strategy, the product supplier should be consulted to determine that the NOx/PM ration of the candidate engine application is adequate to support the use a particular catalyst-based DPF design. E. Installation and Vehicle Modifications

Application and use of DPF technology requires careful engine screening and preparation, regular checking of monitoring equipment, proper engine maintenance and periodic cleaning of the filter element.



PRE-INSTALLATION PROCEDURES

When selecting candidate vehicles/equipment for DPF retrofit, engines that burn excess lubricating oil, require frequent maintenance, or have a record of problems, should be rejected. Reviewing maintenance records and/or communicating with fleet managers and chief technicians will help identify vehicles that should not be included in the program. Also, as discussed above, in situations where a DPF relies on adequate exhaust temperatures to support filter regeneration, data logging of exhaust temperatures from the candidate vehicle/equipment applications over a “worst-case” operating cycle should be performed to determine if the exhaust temperatures are adequate to support filter regeneration.

Prior to installation, vehicles/equipment should be inspected (both the engine and the

exhaust system) and any routine or necessary maintenance performed. This includes checking engine components and, replacing if necessary, such components as fuel injectors (worn injectors can leak fuel into the combustion chamber causing excess PM to collect on the filter) and the turbocharger (turbo-boost failure can lead to excess fuel being dumped into the filter which in turn can cause a catastrophic DPF failure) . INSTALLATION AND VEHICLE MODIFICATIONS

The complexity of DPF installation can vary considerably. In some cases, installation is a relatively straightforward muffler replacement and in other cases, it is more complex because of such factors as limited space to locate the DPF and/or difficulty in accessing and working in the space where the DPF will be fitted. Also, the design of the inlet and outlet of the DPFs and connecting hardware will vary depending on the specific application. In some cases, modifications to the existing exhaust system will be needed. The time needed to perform a DPF installation can vary from as few as two hours to 10 or more hours, depending on the complexity of the installation. An important step in the installation process is for the technology provider to inspect and take measurements of the vehicles/equipment to be retrofitted. If a visual inspection by the technology provider is not possible, than at a minimum, drawing and other data sufficient to ensure proper DPF sizing and assembly design should be provided.

DPFs are often heavier and/or larger than the mufflers they replace. Therefore, care must

be taken to insure that the installation hardware has sufficient strength to support the DPF. Failure to use the appropriate hardware can result in mechanical failure of clamps and brackets and can result in damage to the DPF. Special quick-release brackets are often utilized to facilitate quick removal of the filter for cleaning. Also, unless the exhaust temperatures are clearly sufficient with a large margin safety, insulation material should be installed on the exhaust system between the engine manifold and the inlet of the DPF to help maintain the exhaust temperature. In applications where the vehicle will operate in cold ambient temperatures, insulating the exhaust system is common.



Since DPF installations may be complex, installation is typically performed by the

technology provider or its agent. In those instances where a large number of vehicles/equipment are being retrofitted and a highly professional maintenance staff exists, it may be cost effective, after consulting with the technology provider, to have fleet technicians trained by the technology provider to perform the DPF installations. In those cases in which fleet technicians perform the DPF installation, the technology provider or its agent should oversee the first few retrofits and subsequently at least spot check the installations of a sufficient number of additional retrofits to ensure adequate installation integrity. Finally, DPF installations should be carefully scheduled to minimize vehicle/equipment downtime. Adequate time for installation should be provided, including extra time for any unanticipated problems that may occur. F. Fuel Requirements

DPF systems that do not employ catalyst based strategies and rely on external sources for filter regeneration generally have operated effectively on engines fueled with diesel fuel containing 500 ppm sulfur or, in limited cases high sulfur levels (e.g., underground mining equipment in Canada). Those passive and active DPF systems that employ catalyst-based strategies are adversely affected by the level of sulfur in the fuel.

Sulfur affects filter performance by inhibiting the performance of catalyst materials

upstream of, or on, the filter. This phenomenon not only adversely affects the ability to reduce emissions, but it also adversely impacts the capability of these filters to regenerate; a direct trade-off exists between sulfur levels in the diesel fuel and the ability to regenerate the filter. Sulfur also competes with the catalytic reactions intended to reduce pollution and further creates PM through catalytic sulfate formation.

The vast majority of DPF retrofit projects in the U.S. and Europe use diesel fuel with

sulfur levels less than 15 ppm. The use of this very low sulfur fuel enables filters to use catalytic formulations designed for maximum filter regeneration, for the highest levels of PM reductions, and for the least amount of sulfate generation. The use of diesel fuel with less than 15 ppm sulfur has been a key factor in the success of many program in terms of enhancing filter durability, performance and extended cleaning intervals. Several programs employing DPFs in the U.S. and elsewhere have used diesel fuels with sulfur levels greater than 15 ppm but less than 50 ppm. For example, U.S. projects involving long distance commuter buses, transit buses, and refuse trucks used diesel fuel with sulfur levels less than 30 ppm and reported no adverse impacts



on DPF operating performance. DPF retrofit initiatives in Europe and in the U.S. on select on-road and offroad applications reported success with using fuels less than 50 ppm . One study did report that when a DPF system designed to operate on 10 ppm fuel switched to 50 ppm, a sharp increase in DPF failures occurred. As noted above, engines with catalyst-based DPFs operating on fuel sulfur levels above 15 ppm will have increased production of sulfate that adds to the overall PM levels.

Retrofit projects in the U.S. employing flow-through filters on such applications as

school buses, transit buses and construction cranes are operating on conventional highway diesel fuel containing less than 500 ppm.

G. Maintenance

The principal maintenance item for DPFs is the periodic cleaning of the filter. Also periodic visual inspection of the: 1) DPF assembly hardware to insure the DPF is still firmly connected, 2) outer shell of the DPF for physical damage, and 3) exhaust system for leaks.

Under normal operating conditions, the filter collects the PM and periodically oxidizes

the carbon-based PM. Inorganic material, such as phosphorus, sulfur, calcium, and zinc, derived from the lubricating oil, the sulfur in the fuel, and residue from engine wear will also be collected on the filter. These materials can form oxides and sulfate materials that remain on the filter. Over time, these materials accumulate on the filter and eventually will cause a pressure drop across the filter and cause the engine backpressure to increase. In addition, if the carbon-based PM is not completely combusted, it can also accumulate on the filter and contribute to backpressure increases. Finally, if a FBC is utilized, significant amounts of inorganic material will accumulate on the filter. To avoid backpressure increases above the engine manufacturer’s specification or to reduce backpressure build-up when it occurs, the filter must be cleaned periodically.

Filter cleaning should be performed in accordance with the technology manufacturer’s recommend maintenance schedule or when the backpressure monitor/alarm indicates engine backpressure levels approaching or exceeding the engine manufacturer’s specifications. Recommended cleaning intervals vary widely based on such factors as engine age, engine lubricating oil consumption, whether a FBC is used, vehicle/equipment application, and engine operating cycles. Recommended intervals are typically stated in terms of number of days/mile or hours of operation, which ever occurs first (e.g., annually or every 20,000 miles). In most applications, cleaning at least annually is recommended. Recommended mileage intervals for filter cleaning can range anywhere from 10,000 miles to 80,000 or more miles. For offroad applications, the recommended cleaning is stated in terms of operating rating hours.

In some instances, DPFs have continued to perform effectively well beyond the

recommended cleaning interval. For example, the recommended cleaning interval is every 2,000 hours of operation for construction equipment in Switzerland. In a number of instances however, equipment operated well in excess of 2,000 hours without requiring cleaning. Similarly, several grocery delivery trucks operated over 300,000 miles over three and a half years with one truck requiring no filter cleanings and the remaining vehicles only requiring one cleaning over the three and half year period. Manufacturers of flow-through filters, given the nature of the filter



design, do not typically specify recommended cleaning intervals. However, in some applications using the high PM control efficiency flow-through filters, annual cleaning is recommended. Also, if increased engine backpressure should occur, the filter should be cleaned in accordance with the manufacturer’s recommended cleaning procedure. Several factors can extend the duration between cleaning intervals including: 1) reducing engine oil consumption through engine maintenance and, 2) using lubricating oil formulations with reduced ash forming properties such as low sulfur, zinc, or phosphorous levels. Also, DPF filter manufacturers have taken some steps to improve the ash storage capacity for a given size filter.

Several different types of filter cleaning methods can be employed. After removal from the vehicle/equipment, one popular method to clean the filter is using a combination of a pressurized air gun on one end to clean the filter and an industrial vacuum device at the other end to collect the ash. This approach typically takes less than an hour to complete per filter. Another cleaning method is filter heating/baking by placing the filter in an industrial oven or by using a stand-alone cleaning unit that includes a heating element to burn-off any organic soot remaining on the filter. This approach can take anywhere from eight to 12 hours. In some cases, both methods have been used. The DPF manufacturers will specify the types of cleaning that are appropriate for their DPF design and engine application. Some manufacturers offer automated or semi-automated machines or stand alone work stations for filter cleaning operations. These stations or machines can be designed to include pressurized air streams, vacuum collection, and/or heating capabilities. Fleet personnel can be trained to operate these cleaning devices. In addition, a growing number of organizations including the engine/vehicle OE dealers and distributors are offering cleaning services to fleets. The filter cleaning services include a number of service options including on-site cleaning and reinstallation of the filter at the customer’s facility or “swap and clean” programs that substitute a clean filter element for the filter in need of cleaning.

Ash and other materials removed from the filter should be collected and disposed of in an environmentally appropriate manner. Workers and others should not be exposed to airborne ash; using a vacuum device with a sealed container to collect ash is one example of effective cleaning/collection technique. In some jurisdictions, DPF waste ash is considered to be a hazardous material while in others, it is treated as dry industrial waste. State and local environmental agencies are good sources for determining how DPF waste ash should be treated.



H. Costs

DPF technology costs can be broken down into hardware, installation, maintenance and

operating costs. These costs can vary depending on a number of factors including the horsepower rating of the engine, the vehicle/equipment application and duty cycle and the volume of DPF units received under a given purchase order.

HARDWARE COSTS

In 2002, CARB provided an estimate of DPF hardware costs based on horsepower rating, as shown in Table 3-1.

Table 3-1, Estimated Costs of DPF Technology

Engine Horsepower Hardware Cost 40 $3,300 - $5000 100 $5,000 - $7,000 275 $6,900 - $9,000 400 $10,500 1,400 $32,000 - $44,000

CARB also assumed an additional cost of $50 to $100 to cover installation hardware.

CARB estimates seem to be reasonably in line with the reported costs of DPFs purchased in the U.S. over the past few years. For example, DPFs sold for use on on-road vehicle applications have generally fallen within the $5,000 to $10,000 range. The estimated costs of flow-through filters typically falls somewhere in the range between the cost of conventional DPFs and DOCs (e.g., approximately $3,000±). Information on the cost of DPF hardware for offroad applications is very limited, but the costs are expected to be comparable to, if not somewhat higher than, on-road applications of similar size and horsepower ratings. In some cases, depending on the degree of sophistication and capabilities, the backpressure monitoring system is sold separately. Monitoring systems can range from simple backpressure monitors to sophisticated recoding and diagnostic systems that monitor a number of different parameters including backpressure and exhaust temperature.

DPF manufacturers predict that as the technology is further optimized and the sales

volumes of DPFs in both retrofit and OE applications increase, the hardware costs will be reduced. If this prediction is correct, then the favorable cost impacts of increased volume on price reduction should begin to appear in the 2006-2007 timeframe when the demand for DPFs will increase dramatically to satisfy EPA’s 0.01 g/bhp-hr PM standard for on-road engines. INSTALLATION COSTS

The DPF installation is typically performed by the technology supplier or its distributor. The installation cost is sometimes included in the purchase price, but is often billed as a separate item. As discussed in “Installation and Vehicle Modification”, the time needed to install a retrofit can range from as little as two hours to over 10 hours. At an estimated rate of $65 per hour, retrofit installation costs would typically range from $130 to $650. These costs, however,



could be substantially higher in situations in which complex or time consuming DPF installations are involved. MAINTENANCE COSTS The principal maintenance costs associated with DPF technology is the periodic cleaning of the filter. The actual cost will vary based on factors such as 1) the frequency of cleaning, any where from at the end of every shift to annually, 2) who performs the cleaning whether it be fleet personnel, the technology supplier or an independent third party, and 3) the type of cleaning method employed such as simply reversing the filter, using compressed air, or using a heat source. CARB has estimated that the annual maintenance costs range from $156 to $312 with labor of about two to four hours. OPERATING COSTS

A concern sometimes expressed with utilizing DPFs is that it will adversely impact fuel consumption. However, as is discussed above, virtually all programs that have carefully evaluated the fuel consumption impact have found little or no fuel economy impact from utilizing a modern passive DPF. In those instances in which a fuel is used to facilitate regeneration, a slight fuel economy penalty can be expected. For example, one report noted a decrease in fuel economy of less than 2% for a fuel burner-assisted regeneration system.

For those DPFs systems requiring the use of ULSD, a slight fuel consumption penalty is

possible from using ULSD due to the fuel’s lower energy content when compared to an engine operating on conventional on-road diesel fuel (less than 500 ppm). One report noted a 2%-3% penalty for delivery trucks, but other programs report only a modest or no measurable impact from using ULSD.


VOLUME 2 – Section IV WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

IV. LEAN NOx CATALYST (LNC)


OVERVIEW

LNC technology is a relatively new and emerging technology. The technology has been

successfully applied to new passenger cars in Europe and as a retrofit technology on transit buses, refuse trucks, utility vehicles and offroad equipment such as backhoes. LNC systems are currently capable of achieving NOx reductions in the range of 10% to 25%. LNC designs that use diesel fuel as the reducing agent to facilitate NOx control performance have about a 3% fuel economy penalty.

LNC is an application specific technology and care should be taken in selecting vehicle/equipment applications. In retrofit applications, LNCs can be combined with DOCs, DPFs and crankcase emission control technologies. A LNC/DPF system has been verified by CARB as a retrofit technology achieving at least a 25% NOx reduction and at least an 85% PM reduction (See www.arb.ca.gov/diesel/verdev/verdev.htm).

LNC/DPF systems have, in general, performed very well in retrofit applications in the

U.S. Some systems have been operating for up to several years with little or no problems. A small percentage of LNC/DPFs have experienced instances of premature plugging of the DPF, requiring unscheduled cleaning. Also, in limited cases, plugging also has occurred on the front face of the LNC. The technology manufacturer has made modifications to the system software to alleviate the problem. Finally, as with stand-alone DPF systems, the LNC/DPF system in a few instances had a backpressure monitor malfunction due to the overly sensitive components. The technology supplier has made modifications to the system design to correct the problem. TECHNOLOGY DESCRIPTION

Controlling NOx emissions from a diesel engine is difficult because diesel engines are

designed to run in a lean mode that results in high levels oxygen (“oxygen rich”) in the exhaust. In the oxygen-rich environment of diesel exhaust, it is difficult to chemically reduce the NOx molecules over the catalyst to nitrogen. A LNC conversion of NOx to nitrogen requires a reductant (HC, CO, or H2) and under typical diesel engine operating conditions, sufficient quantities of the reductant are not present. As a result, the conventional three-way catalyst used on gasoline-powered vehicles/equipment cannot be used in diesel engine applications. The LNC was developed to address the issue of catalytic NOx control in the oxygen-rich exhaust environment of diesel engines. Some LNC systems inject a small amount of diesel fuel or other reductant into the exhaust. The fuel or other reductant serves as a reducing agent for the catalytic conversion of NOx to nitrogen. Other LNC designs operate passively to reduce NOx. The LNC support is a porous material, often made of zeolites and encased in a stainless steel container similar to what is used to hold a DOC substrate or a DPF filter. The support or substrate provides catalytic sites that are fuel/HC rich where NOx reductions can take place. An HC/NOx ratio of up to 6:1 is needed to achieve good NOx reductions. The LNC/DPF system

©2005 Emissions Advantage, LLC 2.IV-1 November 18, 2005


includes a backpressure monitor and monitor for the fuel injection dosing system. Figure 4-1 is a photograph of the CARB-verified LNC/DPF system

Figure 4-1, Example of a Lean-NOx Catalyst system

Courtesy of Cleaire


LNC technology is capable of achieving anywhere from 10% to 25% depending on the system design and vehicle/equipment applications. To some extent, NOx control efficiency is dependent on the temperature of the duty cycle; if temperatures are low, the NOx conversion is reduced. Passive systems, such as those used on passenger cars in Europe, achieve NOx reductions of 10±%. Active LNC systems employing a reductant such as those used in retrofit applications in the U.S. have achieved a 25% or greater NOx emission control efficiency. Since the diesel fuel used in active LNCs to reduce the NOx does not produce mechanical energy, active LNC typically operates at a fuel penalty of about 3%. The additional fuel consumption results in a slight increase in CO2 emissions. The CARB-verified LNC includes a catalyst-DPF as part of the system. The DPF is verified to achieve at least an 85% reduction in PM emissions, and will also reduce HC and CO emissions, as well as virtually eliminate diesel smoke and odor.

C. Status and Availability STATUS

Passive LNC technology has been successfully employed on new diesel-powered

passenger cars in Europe as original equipment since the mid-1990s. Retrofit applications of LNCs are a relatively recent development, but the application experience in both the on-road and offroad sectors is growing rapidly. A combined active LNC/DPF system has been used for retrofit applications in the U.S.

In on-road applications, the LNC/DPF system has been applied to transit buses, refuse

trucks, and highway maintenance trucks. For example, over a three year period that began in 2004, up to 2,700 LNC/DPF systems will be installed on transit buses in the San Francisco area of California. A number of other transit agencies throughout California are also equipping LNC/DPF on buses. The California Department of Transportation (CALTRAN) has retrofitted LNC/DPF systems on approximately 120 vehicles with 1994 and later model year engines..



Applications include dump trucks with spreaders and plows, as well as trucks with hoists and trash compactors. In offroad applications, the LNC/DPF system is designed to be installed on offroad equipment with EPA Tier 1 compliant engines rated at 100 horsepower or greater. LNC/DPFs have been installed on backhoes, graders, wheel loaders and back-up generators.

AVAILABILTY

There is currently one manufacturers of a CARB-verified LNC/DPF system. D. Selection and Use Criteria

The LNC/DPF retrofit system, due in large part to the catalyst-based DPF component of

the system, is an application specific technology. The same criteria that apply when evaluating DPFs as a stand-alone technology apply to the LNC/DPF system as well and include:


• Available space to equip the retrofit system.


These criteria are discussed in detail in Section III, DPF Selection & Use Criteria. The

LNC/DPF systems have typically been retrofitted on 1994 and later model years, but in at least one instance the system was retrofitted on a 1988 model year offroad engine. According to the CARB verification, application of this technology requires exhaust temperatures of at least 260°C for at least 25% of the daily duty cycle. Also, the requirements for available space on the vehicle/equipment are increased as the dimensions of the LNC/DPF system can be greater than a DPF stand-alone technology.



E. Installation and Vehicle Modifications

Just as is the case when a DPF is used by itself, the application and use of the LNC/DPF system requires the same care in selecting and preparing the vehicle for retrofit, properly configuring and performing the installation, and properly maintaining the system and vehicle/equipment (see Section II, DPF Installation & Vehicle Modifications).

The LNC/DPF system can be installed as a muffler replacement. However, because the

dimensions (both diameter and length) may be larger than the OE muffler being replaced, care must be taken to insure that adequate space exists to properly install the system. Installation of the system is performed by the technology provider. The retrofit process typically takes up to two days, and in some cases more if a custom fit is required. F. Fuel Requirements

This system is verified to operate only on ULSD (less than 15 ppm sulfur) fuel. This requirement exists to support application of a catalyst-based DPF in the system as well as to maximize the effectiveness of the LNC component.

G. Maintenance

In addition to the maintenance performed on the DPF, on occasion in some applications, the front face of the LNC plugs. In cases where plugging occurs, the LNC element can be removed and cleaned. The injector system providing the diesel fuel as the reductant for the LNC should be inspected periodically and recalibrated or repaired as needed.

H. Costs

The installed cost of the CARB-verified LNC/DPF technology ranges from less than

$15,000 to over $20,000 depending on the vehicle/equipment application, the engine horsepower rating, and the number of vehicles/equipment being retrofitted. Maintenance costs are related primarily to DPF filter cleaning (See Volume 2, Section II, DPF Maintenance Costs). Since this verified system uses diesel fuel as the reducing agent, a small fuel economy penalty (up to approximately 3%) could result in a slight increase in operating costs.


VOLUME 2 – Section V WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

V. SELECTIVE CATALYTIC REDUCTION (SCR)


OVERVIEW

SCR technology has been used on stationary engines for nearly 20 years. More recently,

it has been applied to select mobile sources as OE or retrofit technology on trucks, marine vessels, locomotives, and construction equipment. SCR technology, like LNC technology is a catalyst-based strategy that can reduce NOx in the oxygen-rich exhaust of a diesel engine. SCR technology employs the use of a reductant to facilitate the catalytic NOx reduction process. SCR technology can reduce NOx emissions anywhere from over 25% to over 90%. Certain SCR designs can also reduce HC and CO emissions from 30% to 90% and PM emissions from 15% to 50%, as well as reduce diesel smoke and odor. The emission reductions achieved are influenced by the SCR system design, the engine application, and the operating duty cycle. SCR technology has performed well in OE and retrofit applications and has demonstrated outstanding durability. SCR technology is a vehicle/equipment specific application and care must be taken in designing and applying this technology. Collecting data on the engine operating modes (“engine mapping”) is needed both to screen candidate applications and to properly calculate the rate of reductant dosing needed. The emergence of NOx sensors may reduce, or even eliminate eventually, the need for engine mapping. In the U.S., SCR has started to emerge as a retrofit strategy in selected on-road and offroad applications. An SCR system with 25% NOx reduction and greater than 25% PM reduction has been verified by CARB for limited offroad engine applications (see www.arb.ca.gov/diesel/verdev/verdev.htm). SCR technology can be used in combination with a DPF, a DOC or a Selective Non-Catalytic Reduction (SNCR) system.

SCR systems have been successfully applied to a variety of on-road and offroad applications and have demonstrated impressive durability. SCR systems on heavy-duty trucks have operated effectively for up to 350,000 miles or more. In marine applications, SCR systems performed effectively in the range of 10,000 to 40,000 operating hours.

Problems have been experience in fitting SCR systems on some on-road vehicles. In

addition, there have been start-up issues with the SCR system that required some modifications or adjustments. On rare occasions, operators have complained of an ammonia smell resulting from excess ammonia emissions. This issue is typically addressed by adjusting the reductant dosing. Once start-up issues have been addressed, SCR technology appears to generally operate effectively with out adverse impact on vehicle/equipment performance or fuel economy. In some applications, SCR systems can add 30% to 60% to the weight of the normal muffler system, but other than requiring installation hardware of sufficient strength, no other impacts have been reported. The requirement for a reducing agent does have a slight impact on engine operating costs (a cost in the range of 4% of the vehicle/equipment operating fuel cost).

©2005 Emissions Advantage, LLC 2.V-1 November 18, 2005


TECHNOLOGY DESCRIPTION

An SCR system is designed to catalytically reduce NOx emissions in the oxygen rich

environment of diesel exhaust. The SCR catalytic formulation is coated on a ceramic or metallic catalyst support encased in a stainless steel cylinder. Both precious metal and base metals can be used for exhaust temperatures in the 230°C to 430°C range. For higher temperatures, (360°C to 590°C) zeolite catalysts may be used; precious metal catalysts can be used for low temperatures (175°C to 290°C). Like other catalyst-based emission control technologies, an SCR catalytically converts pollutants without being consumed. To reduce NOx emissions, the SCR system needs a chemical reagent, or reductant, to help convert the NOx to nitrogen. The reductant used in mobile source applications is typically urea or aqueous ammonia. The reductant is added at a rate calculated from an algorithm that estimates the amount of NOx present in the exhaust stream. The algorithm relates NOx emissions to engine operating conditions (e.g., engine speed/load). NOx sensors are emerging that will enable more precise reductant injection to optimize NOx control.

Courtesy of Omnitek

SCR systems installed as muffler replacements provide comparable noise attenuation to

the mufflers they replace. In large marine applications, it has been reported that the SCR provided up to a 30-35 db noise reduction benefit.

SCR systems need a supply of the reductant, which is typically stored on board the

vehicle or equipment and is refilled as needed. Typically, monitoring/warning systems are included as part of the SCR system to alert the operator or mechanic that the reductant supply is getting low or that there is a problem with the reductant injection system. Also, a readily accessible source needs to be available for storing and dispensing the supply of the reductant when the on-board supply is depleted. B. Emission Reduction

As exhaust gases pass over the SCR catalyst, chemical reactions occur that reduce NOx emissions from over 25% to over 90%. The NOx control efficiency is a function of: 1) the SCR catalyst design, 2) the effectiveness of the reductant delivery system to match the proper dosage to the amount of NOx in the exhaust, 3) the engine application, 4) the operating temperatures, 5) the duty cycle (e.g. steady-state or transient), and 6) the sulfur level in the fuel. Where an



oxidation function is added to the SCR system, CO and HC emissions can be reduced from 30% up to 90% and PM emissions reduced by 15% to 50%. Also, diesel odor and smoke will be reduced. Excess ammonia emissions or “ammonia slip” can be emitted out of the tail pipe if the injected reductant is not consumed by the catalytic process. This issue can be effectively controlled by properly metering the reductant and/or by placing a DOC downstream of the SCR catalyst to destroy any excess ammonia.


As noted SCR technology was first introduced in stationary source applications in Europe in the mid-1980s and in the U.S. in the late 1980s. In the 1990s, SCR began to be evaluated as a control strategy for mobile sources. A demonstration project in Europe involving line-haul trucks demonstrated that SCR technology could achieve greater than 80% NOx control over for over several hundred thousand miles of vehicle operation. SCR systems are expected to be installed on on-road heavy-duty engines to help meet the Euro 5 standards in 2008. SCR technology has also been identified as a candidate technology to meet the EPA on-road HDE 2007/2010 standards.

SCR technology has also been installed on buses, construction equipment, marine vessels

and locomotives. For example, since the mid-1990s SCR technology has been installed on over 100 marine vessels in Europe including ferries, tugboats, and cargo vessels. The capacity of the engines equipped with SCR systems ranged from 450 to over 10,000 kW. In the U.S., SCR systems have been retrofitted on refuse trucks, rubber tire excavators, dump trucks, freight transport vehicles and large gantry cranes.

AVAILABILTY SCR systems are available from several manufacturers. Each system is designed for a specific engine/vehicle/equipment application, and is typically custom-configured for the application. D. Selection and Use Criteria

SCR technology is an engine specific technology. Care should be taken in assessing

candidate vehicles/equipment for possible SCR installation. The factors to consider include:

• Proper exhaust temperature window to support SCR technology.

• Adequate space is available to install the SCR system.

• Operating duty cycle to support application of SCR technology.

• Sulfur level in the fuel.

• Available infrastructure for re-supplying the reductant on the vehicle/equipment.



Exhaust Temperature Window – Depending on the type of catalyst or combination of

catalyst used, the exhaust temperature for applying SCR technology is very broad. However, there may be instances where the operating temperature window for a given vehicle/equipment application is too low or too high for a particular SCR system design. Close coordination with the SCR system supplier is needed to insure that the SCR design or designs will function effectively given the operating temperature window for the candidate engine application.

Adequate Available Space – The dimensions of an SCR system are often larger than the existing muffler so finding adequate space to allow for proper installation without interfering with vehicle/equipment operation can be challenging. SCR technology manufacturers, however, continue to make progress in reducing the size of SCR systems. This design improvement is enabling SCR technology to be considered for a growing number of applications. Space must also be found to install the on-board reductant supply containing and injection system.

Operating Duty Cycle of the Application Appropriate for SCR Retrofit – A need exists

with SCR systems to precisely match the amount of reductant introduced with the level of NOx in the exhaust. Transient operations, where the engine operating parameters and in turn the level of NOx emissions can change frequently and rapidly, is a particularly challenging application for an SCR system. In new engine applications, the issue of transient operation can be addressed by designing and melding the engine control system and the SCR technology into an integrated system. In retrofit applications, SCR technology is more easily applied to vehicle/equipment applications in which the operating duty cycle tends to be more steady-state. In that regard, many offroad engine applications tend to have less transient operation than many on-road applications, making those offroad engines good candidates for SCR

Sulfur Level in the Fuel – See “Fuel Requirements” below. Reductant Supply Infrastructure – A supply of the reducing agent must be available on-

board the vehicle/equipment at all times. If the reductant is not available the SCR will not function. Therefore, an infrastructure must be available to replenish the supply on the vehicle/equipment with fresh reductant. Currently, centrally fueled vehicles/equipment or vessels with large on-board reductant storage facilities are better candidates for SCR. For offroad equipment, which typically operate in one location and/or is centrally fueled, maintaining a reductant supply which is readily available when needed is very feasible. E. Installation and Vehicle Modifications

The application of SCR technology requires care in evaluating candidate applications, preparing the engine for retrofit, monitoring SCR system performance, and performing proper engine and SCR system maintenance.

As with other retrofit technologies when selecting candidate vehicles/equipment for SCR

retrofit, engines that burn excess lubricating oil, require frequent maintenance, or have a record of problems should be rejected. Reviewing maintenance records and/or communicating with fleet managers and senior technicians will help identify vehicles that should not be included in the program. The vehicle should be evaluated to determine whether adequate space exists for the SCR unit, the on-board reductant supply container, and the reductant injection system.



Courtesy of DieselNet

Engine mapping is an important step both in screening candidate vehicles/equipment and

in designing the reductant delivery system to match the particular engine operating conditions, optimization of SCR systems for maximum NOx reductions, and to minimize any ammonia slip from the system. Typically, engine mapping is performed by the technology supplier. The process of developing an engine “map” requires that an engine (of the same model as that for which the SCR system is to be installed) be installed on an engine dynamometer and operated over the full range of speed-load conditions to obtain data on NOx emissions at different engine speed-load points. This information is essential for proper design of the urea (or other reductant) injection system. The amount of reductant to be injected is established during the engine mapping process.

Courtesy of Bosch

The SCR system is typically installed by the technology provider. Normal installations

take about a day, although additional time may be needed with complex installations such as where available space is tight or difficult to access.

F. Fuel Requirements

The catalyst used in SCR systems will benefit from the use of low sulfur fuel in terms of improved performance and minimizing sulfate production when precious metal catalysts are utilized. Low sulfur fuel is not a prerequisite, however, for using SCR technology. The SCR



technology verified by CARB is approved for applications using conventional on-road diesel fuel, that typically fall in the 350 to 500 ppm sulfur range.

G. Maintenance

The principal maintenance item for SCR systems is to ensure that the on-board supply of reductant is always available. This requires refilling the storage container at regular intervals. Also, steps should be taken to ensure that the dosing control unit and delivery system are performing as required. Monitoring technology is available both to alert the operator or technician that the reductant supply is getting low and that a reductant dosing problem has occurred. Also, a readily available reductant storage facility will need to be established and maintained to refill the on-board reductant tanks when needed. H. Costs

SCR technology costs vary greatly depending on the engine size, the vehicle application

and whether engine mapping is needed or is already available. CARB, in 2000, estimated the cost of an SCR system to be in the range of $50 to $60 per horsepower. For a 275 horsepower engine, this cost would translate into a range of $13,750 to $16,500 and for a 750 horsepower engine into a range of $37,500 to $45,000. CARB also estimated the installation costs at anywhere from $500 to $5,000 depending on the application and whether engine mapping was required. Operating costs for SCR system include the cost of the reducing agent. The cost of the urea will vary depending on the quantity purchased. The fuel equivalent cost of reducing agent such as urea typically runs in the range of 4% of the cost of fuel consumed.


VOLUME 2 – Section VI WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

VI. SELECTIVE NON-CATALYTIC REDUCTION (SNCR)

TECHNOLOGY OVERVIEW AND DESCRIPTION

As noted previously, conventional three-way catalyst technology will not function effectively in the oxygen-rich environment of diesel exhaust. SCR and LNC technologies employ a reducing agent in combination with catalyst technology to achieve a reduction in NOx emissions. Another approach for achieving NOx reductions in diesel exhaust is selective non-catalytic reduction or “thermal DeNOx” as it is sometimes called. With SNCR, a reducing agent such as ammonia, is added to the high temperature (greater than 925°C) area of the exhaust stream of a diesel engine. It is reported that for NOx reduction to occur, the engine exhaust temperature must be strictly controlled to within a narrow temperature window of 925°C to 1,125°C in order to maintain the NOx reduction selectivity of the SNCR process. Some NOx reduction can also occur in the 725°C to 925°C temperature range. SNCR has been widely used in stationary source applications, but as a stand-alone approach, it is not well suited for mobile source applications where exhaust temperatures as low as 125°C are often found (e.g., at idle).

SNCR combined with SCR technology has been evaluated on mobile sources with NOx

emission reductions in the range of 80% or more. In an SCR/SNCR system, a control system meters the ammonia into the high temperature exhaust stream, allowing the non-catalytic chemical reduction of the NOx to occur. The exhaust then enters the SCR catalyst where NOx is further reduced. One study reported that an SCR/SNCR system installed on a Cummins 5.9 liter engine, achieved reductions of 78% for NOx, 27% for PM, 65% for HC and 76% for CO. There is very limited experience in the U.S. with SCR/SCNR systems for mobile applications.

Courtsey of KleenAir

©2005 Emissions Advantage, LLC 2.VI-1 November 18, 2005

VOLUME 2 – Section VII WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

VII. LOW PRESSURE EXHAUST GAS RECIRCULATION (EGR)


OVERVIEW

EGR reduces engine-out NOx emissions by recirculating a portion of the engine’s exhaust

and then introducing it upstream of the engine in order to dilute the oxygen content of the ambient air entering the engine combustion chamber. Reducing the oxygen content lowers the combustion temperature, which in turn results in less NOx being formed. EGR systems can reduce NOx by up to 40% or more. Two types of EGR systems exist: high-pressure EGR, which is currently used in new engine applications and low-pressure EGR, which is used in retrofit applications. In OE applications, high-pressure EGR systems are being installed to help meet EPA’s current on-road HDE 2.0 g/bhp-hr NOx standard and are a leading candidate for use in meeting the more stringent NOx reduction requirements that take effect in 2007.

In retrofit applications, low-pressure EGR is being combined with DPF technology and

applied to on-road and offroad engines applications. The EGR/DPF system is an application specific technology. The types of factors that must be considered in applying this technology are the same as with a stand-alone DPF system (See Volume 2, Section III, “Selection and Use Criteria”). Over 3,000 EGR/DPF systems have been installed in Europe and the U.S. System performance, in general, has been quite good; retrofit applications have not experienced the type of problems encountered with OE high-pressure EGR/DPF systems. This technology has been verified by CARB (www.arb.ca.gov/diesel/verdev/verdev.htm).

A number of projects involving low-pressure EGR/DPF systems are now underway. Few

problems have been reported. In some applications, as with any retrofit technology being introduced, there were some start-up issues such as properly configuring the system on a given vehicle application. Also, as is the case with stand-alone DPF installations, some issues with premature filter plugging have occurred due in large measure to issues related to inadequate exhaust temperatures to ensure that the filter regenerates properly. This resulted in some unscheduled downtime to remove and clean the filter.

Other than the items mentioned above, no reported adverse impacts on vehicle/equipment

operation were reported. Information on the possible impact of low-pressure EGR/DPF technology on fuel economy is very limited. One study reported a 1% to 4% fuel economy penalty, depending on the particular engine and test cycle used. The degree of fuel economy impact, if any, is likely influenced by such factors as level of NOx control efficiency, the engine, the application and the operating duty-cycle.

TECHNOLOGY DESCRIPTION

EGR technology involves recirculating a portion of an engine’s exhaust back into the

turbocharger inlet, or the intake manifold of a naturally aspirated engine. In most EGR systems, an intercooler lowers the temperature of the recirculated exhaust. The recirculated exhaust, which has a higher heat capacity and contains less oxygen than the ambient air lowers the combustion temperature of the engine, thereby reducing NOx formation. In retrofit applications,

©2005 Emissions Advantage, LLC 2.VII-1 November 18, 2005


a low-pressure EGR system has been combined with a catalyst-based DPF. The DPF collects PM from the exhaust, including exhaust that is recirculated. Preventing the PM in the exhaust from being re-introduced into the combustion process is critical to the proper functioning of the retrofit EGR system. Unlike high-pressure EGR that is integrated as part of the engine system, low-pressure does not require engine modifications.

Courtsey of Johnson Matthey


Retrofit low-pressure EGR systems can achieve NOx emission reductions of 25% to over 50%. The level of NOx control is influenced by the EGR system design, the engine application, engine calibration, and the operating duty-cycle.

EGR systems do not reduce other exhaust pollutants, but in retrofit applications, low-

pressure EGR is combined with a catalyst-based DPF. Therefore, the system provides up to over 90% reduction in PM, up to 90% reduction in CO and HC (including toxic HCs), and virtually eliminates diesel smoke and odor. It has been reported that the EGR component of the system helped reduce the NO2 formed by the DPF. Where the DPF portion of the system is installed as a muffler replacement, the noise attenuation of the DPF is comparable to, or better than, the muffler it replaces.




Low-pressure EGR/DPFs have been retrofitted on approximately 3,000 on-and off-road engines in the U.S. and Europe. Applications include transit buses, refuse trucks and utility vehicles. For example, over 700 transit buses have been retrofitted with low-pressure EGR systems in Texas. Current experience with low-pressure EGR/DPF systems is in the range of 180 horsepower to 450 horsepower, with new, larger EGR/DPF system being offered to cover applications up to 1,000 horsepower. AVAILABILTY

There are currently at least two suppliers of low-pressure EGR systems for retrofit applications, one of which has received CARB verification. D. Selection and Use Criteria

Since the retrofit low-pressure EGR system incorporates a catalyst-based DPF, it is an

application specific application. The criteria that must be evaluated are the same as when considering the application of a catalyst-based DPF as a stand-alone technology. Briefly, in making the decision whether a low-pressure EGR/DPF system can be applied, the following criteria must be considered:


• Available space to equip the low pressure EGR/DPF system.


These criteria are discussed in detail above in Volume 2, Section III, “DPF Selection and

Use Criteria”. E. Installation and Vehicle Modifications

Given the complexity of the low-pressure EGR/DPF system, care should be taken in selecting and preparing the vehicle/equipment to be retrofitted and in installing, monitoring, and maintaining the system. The issues related to these factors are generally the same as when a DPF is retrofitted as a stand-alone technology. (See Volume 2, Section III, “DPF Installation and Vehicle Modification”). Installing the low-pressure EGR/DPF is performed by the technology provider and typically takes a two-person team up to eight hours to install the system.



Courtesy of Johnson Matthey


Since catalyst-based DPF technology is used as part of the system, ULSD must be used. (See Volume 2, Section III, “DPF Fuel Requirements”).

G. Maintenance

The issues related to these factors are generally the same as when a DPF is retrofitted as a stand-alone technology. (See Volume 2, Section III, “DPF Maintenance”).

H. Costs

The installed cost of the low-pressure EGR/DPF systems have ranged from $15,000 to

$18,000, depending the engine application to be retrofitted. The maintenance costs are primarily for DPF filter cleaning (See Volume 2, Section III, “DPF Costs”).


VOLUME 2 – Section VIII WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

VIII. CLOSED CRANKCASE VENTILATION (CCV) EMISSION

CONTROL


OVERVIEW

Diesel engines (as well as gasoline engines) leak some combustion gases through the engine piston rings. These gases are often referred to as “blow-by” and they pressurize the engine crankcase, which serves as the reservoir for the engine lubricating oil, picking up engine oil mist as they exit the crankcase vent. Blow-by gases that leave the crankcase also are referred to as “crankcase emissions” and they contain products of fuel combustion, partially combusted engine lubricating oil, and oil droplets.

Crankcase emissions from diesel engines can be substantial. To control these emissions,

some diesel engine manufacturers make closed crankcase ventilation (CCV) systems, which return the crankcase blow-by gases to engine for combustion. CCV systems prevent crankcase emissions from entering the atmosphere. Aftermarket open crankcase ventilations (OCV) are available which provide incremental improvements over engines with no crankcase controls, but they still allow crankcase emissions to be released into the atmosphere.

A retrofit CCV crankcase emission control (CCV) system has been introduced and

verified for on-road applications by both the U.S EPA and CARB (see www.epa.gov/otaq/ retrofit/retroverifiedlist.htm, and www.arb.ca.gov/diesel/verdev/verdev.htm) in combination with a DOC. In the U.S., this verified CCV/DOC system has been applied to such applications as school buses and offroad equipment used at marine ports. The filter in the CCV system must be replaced periodically. The CCV/DOC system does not impact vehicle/equipment performance or fuel economy.

Properly installed and maintained CCV crankcase controls in both OE and retrofit

applications, including the verified CCV/DOC system, have performed effectively in on-road and offroad applications. Also, they do not adversely impact vehicle/equipment performance or fuel economy. If, however, the disposable filter is not replaced at the appropriate interval, the filter can clog. This can cause a pressure buildup in the crankcase and can lead to crankcase seal leakage and possible reduction in engine performance. TECHNOLOGY DESCRIPTION

Crankcase emissions from diesel engines without CCV controls can be substantial, as

much as 0.7 g/bhp-hr during idle conditions, even on relatively recent model year engines. Crankcase emissions include pollutants related to fuel combustion (e.g., PM), hydrocarbon aerosols, heavy HC materials and non-organic material from engine lubricating oil.

The closed crankcase ventilation system, which is part of the CCV/DOC verified system, virtually eliminates crankcase emissions (over 90%) during all engine-operating modes. The CCV system consists of a filter housing with a disposable filter that must be periodically replaced, a pressure regulator, a pressure release valve, and an oil check valve. A schematic

©2005 Emissions Advantage, LLC 2.VIII-1 November 18, 2005


illustration of the system is shown in Figure 8-1. A picture of the CCV filter housing is shown in Figure 8-2.

Figure 8-1, Schematic Illustration of a CCV System

Courtesy of Donaldson Company

Figure 8-2, Picture of CCV Filter Housing

Courtesy of Donaldson Company


Crankcase emissions range from 10% to 25% of the total engine emissions, depending on the engine and the operating duty cycle. Crankcase emissions typically contribute to a higher percentage (up to 50%) of total engine emissions when the engine is idling. As noted above, the verified CCV technology is designed to virtually eliminate the crankcase emissions. The combined CCV/DOC system, according the U.S. verification documents, controls PM emissions by up to 33%, CO emissions by up to 23% and HC emissions by up to 66%. A recent program



assessed the impact of CCV /DOC systems on the in-cabin air quality of a school bus. The study reported that the system reduced the particle count by 54% to 62%, depending on the DOC technology used.


CCV crankcase emission control technology is currently being used in OE applications in

Europe and the U.S. In the future, CCV crankcase controls in the U.S. will be required on on-road HDEs beginning in 2007 and to meet the Tier 4 nonroad emission standards that will be phased in beginning in 2011.

The verified closed crankcase ventilation CCVC/DOC retrofit system has been applied to

both on-road and nonroad applications. In the U.S. alone, over2,000 diesel engines have been equipped with this system. For example, a number of school districts have equipped school buses with CCV/DOC systems. The State of Washington will treat both CCV/DOC and CCV/DPF systems as eligible for state funding under its school bus retrofit program. Several marine ports located on the west coast of the U.S. are in the process of retrofitting up to 500 pieces of equipment, such as yard hustlers, with CCV/DOC systems

AVAILABILTY

There are currently several suppliers of open and closed crankcase ventilations systems, however, only one has been EPA-and CARB-verified with a DOC as a system. D. Selection and Use Criteria

The application of CCV emission controls is quite broad. For example, the verified

CCV/DOC system is approved for use on 1991-2003 on-road medium-duty and heavy-duty 4-cycle, non-EGR, and either turbocharged or naturally aspirated (175 horsepower to over 250 horsepower) engines. This technology has also been applied to a variety of offroad applications and a specially designed CCV emission control system can be applied to engines over 500 horsepower. Nevertheless, care should be taken to ensure that the appropriate CCV technology matches the specific engine application. Installing the wrong CCV design can affect the filter efficiency/durability and could affect engine performance. Also, the equipment should be inspected to insure that adequate space exists to properly install the retrofit CCV system. Lack of available space on the vehicle or equipment has precluded the use of the CCV/DOC system in some applications. E. Installation and Vehicle Modifications

The retrofit CCV emission control is typically installed by the technology supplier. While the filter housing in some cases has been installed on the engine, to avoid problems with engine vibration or movement, it may be advisable to mount the housing on some other part of the vehicle such as the frame rail. The filter housing should also be mounted in a location that is easily accessible for servicing the filter.




There are no special fuel requirements for use with CCV systems.

G. Maintenance

Replacement of the disposable filter is very straightforward and can be performed as part of the engine oil change servicing. Recommended filter replacement intervals vary based on the number of hours the vehicle/equipment is operated. For high mileage on-road engines, the maximum recommended interval between replacements is every 25,000 miles. For low-mileage vehicles, lower mileage intervals are recommended and replacement at least annually may be appropriate. H. Costs

The cost of the retrofit CCV emission control product is in the range of $450 and the

costs of the verified CCV/DOC system ranges from about $1,200 to slightly over $2,000, depending on the engine application and the number of units sold under a given purchase order. The CCV/DOC retrofit system installation typically requires two to three hours, but in some cases more time is required. Installation costs are typically charged on an hourly basis. The disposable filters are replaced at recommended intervals and the filter cost ranges from $30 to over $40.


VOLUME 2 – Section IX WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

IX. ENGINE ELECTRONIC CONTROL MODULE (ECM)

REPROGRAM


In October 1998, a court settlement was reached between the EPA, Department of Justice, CARB and engine manufacturers (Caterpillar, Inc., Cummins Engine Company, Detroit Diesel Corporation, Volvo, Mack Trucks/Renault and Navistar/International) over the issue of high NOx emissions from heavy-duty diesel engines during certain driving modes. Since the early 1990s, the manufacturers used software in the electronic engine control module (ECM) that caused engines to switch to a more fuel-efficient (but higher NOx) driving mode during “off-cycle” steady highway cruising. These engines were built between 1993 and 1998 in a way that allowed the engines to pass EPA emission certification tests but increased emissions while the vehicle was being operated under conditions not included in the Federal Test Procedure (FTP) emission testing cycle used to establish compliance with EPA heavy duty engine emission standards. It is estimated that 1.3 million engines contain the “off-cycle” ECM software.

The court settlement required the companies to introduce cleaner engines (including development of engines meeting the 2004 emission standards by October 2002, 15 months ahead of time), rebuild or reprogram older engines to cleaner levels, recall pickup trucks that have the so-called “defeat devices” and conduct new emissions testing. As part of the manufacturers’ requirements to rebuild or reprogram older engines (1993-1998) to cleaner levels, companies developed a heavy-duty diesel engine software upgrade (known as an ECM “reprogram”, “reflash” or “low NOx” software) that modifies the fuel control strategy in the engine’s ECM to reduce the excess NOx emissions

Courtesy of Detroit Diesel Corporation


On road engines with low NOx software are required to meet NOx emission standards based on the two options shown in Table 9-1, where Medium Heavy-Duty Diesel Engines (MHDDE) are used in vehicles with Gross Vehicle Weight Restrictions (GVWRs) of 14,001 to 33,000 pounds and Heavy Heavy-Duty Diesel Engines (HHDDE) are used in vehicles with GVWRs greater than 33,000 pounds.

©2005 Emissions Advantage, LLC 2.IX-1 November 18, 2005


Table 9-1, Low NOx Engine Software Certification Options

Option A Option B

Model Year/ Test Cycle

Application/ Emission Standard

Model Year/ Test Cycle

Application/ Emission Standard

1994-98 MHDDE HHDDE 1993-98 MHDDE HHDDE SET 6.0 g/bhp-hr 7.0 g/bhp-hr SET 6.5 g/bhp-hr 7.5 g/bhp-hr NTE 7.5 g/bhp-hr 8.75 g/bhp-hr NTE 8.1 g/bhp-hr 9.38 g/bhp-hr

Current Federal regulations do not require that complete heavy-duty diesel vehicles be emission-certified using a chassis dynamometer (as is used for light-duty vehicle emission testing), instead requiring that a manufacturer’s engines be certified using an engine dynamometer. Consequently, the basic emission standards are expressed in g/bhp-hr (grams per brake horsepower-hour) and require heavy-duty diesel engine emission testing over the Transient FTP engine dynamometer cycle. For comparison, the EPA FTP NOx emission standard for 1993-97 heavy duty diesel truck engines was 5.0 g/bhp-hr and was 4.0 g/bhp-hr for 1998 heavy duty diesel truck engines. The NOx level for an older offroad diesel engine that was not required to meet any emission standards is typically over 10 g/bhp-hr.

Low NOx software was developed by the engine manufacturers to achieve compliance with existing emission standards (for the specific year of manufacture). Thus, the software, in and of itself, as developed for satisfaction of the 1998 consent decree requirement does not constitute a means to reduce emissions below the emission standards that were in place for the specific year of manufacture, in the classic sense of diesel emission reduction retrofit products. Catalytic exhaust aftertreatment retrofit products (typically a DOC or DPF) have been combined with (legally required) ECM reprograms for at least two engine manufacturers (International and Cummins) to create retrofit systems that reduce NOx, PM, HC and CO emissions below the emission standards that were in place for the year of engine manufacture. The system for Cummins 1994 through 1998 M11 engines has been verified by CARB as providing emissions reductions of 85% for PM and 25% for NOx. The International system is claimed to meet the U.S. EPA 2007 heavy-duty diesel engine emissions standards for PM and HC, and to be allowed by CARB as being qualified to share in California funding of new school bus purchases under the DRRP. C. Status and Availability To date, over 60,000 heavy-duty vehicles have received ECM reprogramming. CARB has now required ECM reprogramming to be done on all applicable vehicles (estimated at between 300,000 and 400,000). The number of offroad engines receiving ECM reprogramming is not known.

ECM reprogram installations are available in California and throughout the U.S. at engine dealers and distributors. Low NOx software can be arranged to be installed at the local engine dealer/distributor or in instances where a large fleet operator is involved, the software can be installed on-site.



D. Selection and Use Criteria

An ECM reprogram can be accomplished on only certain on-road and offroad engines. Obviously, an ECM reprogram can be accomplished on only engines equipped with electronic engine controls. Many offroad engines are not electronically controlled, and so cannot benefit for ECM reprogram technology. E. Installation and Vehicle Modifications

The average ECM reprogram requires approximately 15 to 30 minutes for installation. One potential concern is for the engine’s ECM to fail after a low-NOx software install. Based on limited information provided to CARB, failure rate of the engine’s ECM is less than 1% as a result of the reprogram installation F. Fuel Requirements

Since low NOx software only entails reprogramming the engine’s ECM, there are no fuel requirements for an ECM reprogram. However, manufactures have reported negligible impacts on fuel economy. Several fleets had the software installed prior to engine rebuilds and have reported no noticeable differences in their fuel use. CARB has recognized that there may be an average fuel economy penalty and expects it to be less than 1%. In addition, there have been no complaints regarding vehicle performance as a result of ECM reprogram installations. G. Maintenance There are no maintenance requirements for low NOx software. H. Costs

The engine manufactures agreed, as part of their consent decrees, to voluntarily provide

low NOx software upgrades free of charge to on-road vehicle owners and operators at the time of engine rebuild or upon request. However, some engine manufacturers are not installing the ECM reprogram free of charge unless it is installed in conjunction with an engine rebuild. Consequently, dealer/distributors are passing on 30 minutes to one hour of labor charges to vehicle owners that choose to have the ECM reprogram installed without an engine rebuild. CARB has been in contact with the engine manufactures to rectify the problem so that the only cost to the owner/operator is the out-of-service time for the vehicle. The cost of having an ECM reprogram performed for an offroad engine that can benefit from it is not known, however, there is likely to be some cost associated with the process since the consent decrees did not apply to offroad engines.

The ECM reprogram retrofit systems that include an exhaust aftertreatment retrofit product typically involve an additional cost beyond that of the exhaust aftertreatment product.


VOLUME 2 – Section X WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

X. ULTRA LOW SULFUR DIESEL (ULSD)

A. Product Overview and Description

The EPA’s diesel fuel regulation limits the sulfur content in highway diesel fuel to 15

ppm (by weight), down from the previous 500 ppm. Refiners will be required to start producing the 15 ppm sulfur fuel beginning June 1, 2006. At the terminal level, highway diesel fuel sold as low sulfur diesel fuel must meet the 15 ppm sulfur standard as of July 15, 2006. For retail stations and wholesale purchasers, highway diesel fuel was originally required to meet the 15 ppm sulfur standard by September 1, 2006, however the implementation date was extended to October 15, 2006 because of refinery production and distribution disruptions caused by the hurricanes of 2005. Refiners can also take advantage of a temporary compliance option that will allow them to continue producing diesel fuel with up to 500 ppm sulfur content in 20% of the volume of diesel fuel they produce until December 31, 2009. In addition, refiners can participate in an averaging, banking and trading program with other refiners in their geographic area. ULDS will be required for use in offroad equipment beginning in 2010. B. Emission Reduction

Without the use of any other emission-reducing technology, the lower sulfur content of ULSD allows engine-out PM reductions of several percent (about 0.8% per 100 ppm reduction in sulfur content) compared to conventional highway low sulfur diesel fuel.

C. Status & Availability

The U.S. Department of Energy, Energy Information Administration (DOE-EIA) has estimated that in 2004, 137 million gallons of ULSD were produced (prior to EPA’s mandate) and made available in several areas of the country (primarily the West Coast, Mid-Atlantic, upper Mid-West, and the metro Houston areas) as a "technology enabler" to pave the way for advanced, sulfur-intolerant exhaust emission control technologies, such as DPFs and LNCs which will be needed to meet the 2007 emission standards. D. Selection & Use Criteria

ULSD enables catalyst-based retrofit technologies such as DPFs and DOCs to operate at

maximum emission control efficiencies and effectiveness.

The lower sulfur content of ULSD has the benefit of reducing the acidic compounds that can promote fuel system corrosion, however, fuel-bound sulfur can help to promote fuel lubricity. The significant reduction of sulfur in ULSD, compared to conventional low sulfur diesel fuel can lead to increased wear in fuel injectors, particularly in older vehicles. Elastomer materials used in O-rings, seals and gaskets contained in fuel system components can also be degraded and fail. The diesel fuel industry is aware of this and is incorporating lubricity additives in ULSD to maintain lubricity.

©2005 Emissions Advantage, LLC 2.X-1 November 18, 2005


The significant majority of operators currently using ULSD have reported no problems with ULSD usage or delivery. Typical start-up problems involved failure of fuel pump seals on older model vehicles, plugged fuel filters, and leaking fuel system O-rings. Once the filters and O-rings were replaced, no further problems were experienced. Another problem identified was the need for periodic replacement of fuel dispensing equipment filters to achieve proper sediment and water control. This is a typical equipment maintenance practice and not considered unusual. Most ULSD users have not reported any impact on fuel economy when switching from regular low sulfur diesel fuel to ULSD. One user reported that test data taken at various intervals throughout the project indicated that the ULSD it used contained about 4% less energy content than regular low sulfur diesel fuel, but that the impact on fuel economy was minimal (approximately 0.15%). Another user operating line-haul delivery trucks reported a 3.54% fuel economy penalty attributable to the ULSD fuel it used. In both cases, the grade of fuel was not specified. Furthermore, rigorous and extensive data collection procedures and involved statistical analysis would need to be performed to be able to segregate the fuel economy effect of ULSD from that caused by other factors, including any other retrofit technology products. E. Costs

The high differential cost between regular diesel and ULSD in some areas is due to

special handling and delivery requirements. This high cost is another impediment to initiating programs with DPF, LNC/DPF and low-pressure EGR/DPF technologies. Public fleets that have installed DPFs on fleet vehicles and initially had the cost differential funded by a government grant, face a dilemma once that funding stops. A ULSD cost differential as high a $0.20 per gallon or more adds significantly to a fleet’s operating expenses and creates additional problems for continuing the program. Programs that have been successful in promoting the widespread use of ULSD to multiple public fleets (school bus, transit and city fleets) in a close geographic area have been successful in obtaining a supply of ULSD with a lower price differential ($0.03 to $0.05 per gallon). F. Product Quality, Delivery, Storage and Fueling

ASTM International has developed a fuel specification specific to ULSD. The Engine Manufacturers Association (EMA) recommends that anyone using ULSD do so with ULSD fuels meeting ASTM fuel specification D 975, and further, that the fuel have a minimum cetane number of 40, a minimum lubricity level of 3100 grams, and a minimum thermal stability value of 70% reflectance after aging for 180 minutes at a temperature of 150°C. Overall, the use of ULSD is expected to be transparent to vehicle users.

It is important to note that the energy content of ULSD is not inherently lower than that

of diesel fuel of higher sulfur content. As shown in Figure 10-1, the energy content of the most widely used diesel fuel grades (No. 1, No. 2, and No. 4) vary by nearly 15% across all of the grades. The energy content can vary by up to 5% for No.2 diesel fuel, and by up to 2.5% for No. 1 diesel fuel. Note from Figure 10-1 that the energy content of No. 1 diesel fuel (which is often used as a blending component to winterize the No. 2 grade in areas with abnormally cold temperatures) is lower than that of No.2 diesel fuel, which is lower than that of No.4 diesel fuel



(which is typically used in large diesel engines, particularly for marine applications). Also note that for these fuels, the relationship of energy density to specific gravity and API gravity is essentially linear. More dense (or “heavier”) fuels have a higher energy content than fuels of lower density. Since fuel economy is directly related to the energy content of a fuel, if all other things are equal, use of a fuel with a higher energy content would improve fuel economy, and vice versa.

Figure 10-1, Energy Content of Diesel Fuels

Energy Content vs API Gravity and Specific Gravity

120,000

125,000

130,000

135,000

140,000

145,000

15 20 25 30 35 40 45 50 55API Gravity - Degrees

Ener

gy C

onte

nt (L

HV)

- B

tu/G

al

RANGE FOR No. 4 DF

RANGE FOR No. 2 DF

RANGE FOR No. 1 DF

Specific Gravity 0.935 0.909 0.882 0.856 0.837 0.801 0.773

The ASTM International specification for diesel fuels (currently D 975-04c) contains no

specification for diesel fuel energy content or API gravity. However, the National Conference on Weights and Measures (NCWM) and the EMA proposed definitions for so called “Premium Diesel” to ensure that consumers receive a functional benefit. To be sold as Premium Diesel fuel, the fuel must meet the minimum values for at least two of five criteria: 1) heating value (energy content), 2) cetane number, 3) low temperature operability, 4) thermal stability, and 5) fuel injector cleanliness. Thus, those that purchase Premium Diesel (of any grade) may also not be assured of getting fuel with a minimum energy content.

Diesel fuel users that are concerned about fuel quality can use a fuels hydrometer to

determine the API gravity (and thus the energy content, as shown from the relationship in Figure 2-6). Fuels hydrometers are available for less than $50 to allow the API gravity of fuels to be checked at the point of delivery to the fleet, thus providing an inexpensive means of checking the energy content (and first ordered quality check) of the fuel being delivered to the fleet. Checking the API gravity of fuel deliveries is a routine practice carried out in the aviation industry and is used as a one means for identifying fuel quality problems.



In general, while the sulfur content of a fuel is not directly related to its energy content,

some refinery processing methods used to remove sulfur from petroleum to the lower levels now required can alter the properties of the finished fuel in a way that results in a less dense fuel, for the same grade. Overall, as production of ULSD becomes widespread, the DOE-EIA estimates that an overall slight decline of 0.5% to 1.8% in energy content of ULSD might be possible.

To maintain the sulfur content integrity of ULSD, pipelines and the equipment used for

fuel transport and storage must be well maintained and kept free from contaminants. This includes excess sulfur residue that may have accumulated from prior handling of diesel fuels with higher sulfur content. Measures should also be taken to prevent vehicle misfueling with higher level sulfur content fuels and the resultant problems that can occur with sulfur-sensitive retrofit products such as DPFs. To minimize the chances of misfueling a vehicle with regular diesel fuel, signage warning of the need to refuel with ULSD can be developed and displayed in prominent places on vehicles and equipment refueling. Vehicle filler caps can also equipped with locks, the keys to which are available to only authorized personnel.


VOLUME 2 – Section XI WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

XI. BIODIESEL


Biodiesel is a renewable distillate fuel derived from a number of vegetable oils, animal

fats, or used frying oils. These oils are converted into methyl esters before they are used as diesel fuel. ASTM International defines biodiesel as the “mono alkyl esters of long chain fatty acids derived from renewable lipid feedstocks, such as vegetable oils and animal fats, for use in compression ignition engines.” In the 1980s and 1990s significant R&D was conducted to evaluate a variety of biodiesel blending stocks, develop emissions data, assess engine/vehicle performance, and develop cost-effective manufacturing processes. Pure biodiesel is referred to as B100, while biodiesel blends with petroleum-based diesel fuel are referred to as BXX, where “XX” is the volume percent of biodiesel fuel blended with the petroleum-based diesel fuel.

In comparison with petroleum-based diesel fuel, biodiesel is characterized by:

• Lower heating value (by about 10-12%). • Higher cetane value (typically 45-60).

• About 11% oxygen content (petroleum-based diesel contains no oxygen).

• No aromatics contents (and no PAHs).

• No sulfur or extremely low sulfur content.

• Better lubricity.

• Higher viscosity.

• Higher freezing temperature (higher cloud point and pour point).

• Higher flash point.

• No toxicity or low toxicity.

• Biodegradability.

• Different corrosive properties.

Some of the above properties, such as the high cetane value or good lubricity, are obvious advantages of biodiesel while others, including the lower heating value, high freezing point (and inferior flow properties at low temperature), or corrosion properties are its drawbacks. Biodiesel changes the character and can increase the intensity of the odor of diesel exhaust (see www.dieselnet.com).

©2005 Emissions Advantage, LLC 2.XI-1 November 18, 2005



Biodiesel fuel can reduce PM, HC, and CO emissions, but typically increases NOx emissions (largely because of the chemically bound oxygen found in biodiesel). The percentage of emission reductions and increase in NOx is a function of the percentage of the fuel blend that is comprised of biodiesel.

Since the biodiesel base stock can come from a variety of sources (several different

vegetable oils, animal fats, waste cooking oils, etc.), the specific fuel properties vary somewhat, depending on the biodiesel source and degree of processing refinement. Thus, the specific emissions effects vary according to biodiesel fuel composition. Several studies and assessments of emissions from biodiesel have been completed, including extensive work by the U.S. EPA. The general emission trends for a “generic” B20 blend with today’s conventional highway low sulfur diesel fuel compared with 100% conventional highway diesel fuel typically shows for total PM emissions, B20 provides about a 10-15 % reduction; for CO and HC (including the air toxics components of HC emissions), 0 to 10% reduction; for sulfate emissions (formed from SO2 emissions), up to a 20% reduction; and for NOx, up to a 10% increase. PM2.5 reductions comprise about 3% or less, of the 10% reduction for total PM.

The NOx increase is a function of engine fuel/emission control systems design, and several biodiesel properties, including cetane value, oxygen content, density, and physical properties, all of which vary with the specific biodiesel base stock. Some newer diesel engines (produced in 2002 and later) have shown less of a propensity for a NOx increase with B20. Research has shown that for older engines, injection timing changes can reduce or eliminate the NOx increase, but performing these changes is not recommended. Certain types of additives mixed with B20 were found to reduce or eliminate the NOx increase.

Compared to petroleum-based diesel fuel, biodiesel has been shown to reduce vapor-phase hydrocarbons in the C1 to C12 range, aldehydes and ketones, PAH and NPAH emissions, and has generated no new emission species compared to those currently present in diesel or biodiesel exhaust. C. Status & Availability

According to the National Biodiesel Board, current and proposed biodiesel production plants are located in 20 states in the U.S. More than 1000 distributors are making biodiesel available in all 50 states (see www.biodiesel.org).

Researchers from South Dakota State University and the University of Missouri-

Columbia undertook a survey of U.S. state transportation agencies to collect performance, storage and economic information related to the use of biodiesel fuels, and found that B20 was the most common biodiesel blend used across the country. This survey found five states that have mandated the use of biodiesel in state government vehicles, and that nearly 65% of the states in the U.S. reported either considering or enacting biodiesel blended fuel mandates, or using biodiesel blended fuel. Table 11-1 illustrates the states that currently require the use of biodiesel in some form, and those that offer incentives for biodiesel production or use, or both. Nearly 40% of the states indicated some level of experience using biodiesel blend, either in tests



or as policy. In addition, there are a multitude of non-state DOT government agencies and private sector fleets that have either tested or are currently using biodiesel blends. B20 is an allowable fuel for satisfying the state government and fuel provider requirements for alternative fuel vehicle acquisition/usage under the Energy Policy Act of 1992 (EPACT).

Table 11-1, States Requiring Use of Biodiesel or Providing Incentives

State Legislation Requiring Biodiesel Use

Legislation Providing Incentives for Biodiesel

Production or Use Arkansas X Iowa X Idaho X Illinois X X Indiana X Kansas X Kentucky X X Maryland X Michigan X1 X Minnesota X Missouri X X Mississippi X Montana X North Carolina X North Dakota X Nebraska X New Jersey X Rhode Island X South Dakota X Texas X Washington X X

1 Approved by the Michigan House Agriculture Committee. Pending approval in the Michigan House

There are several U.S. projects that have documented the use of biodiesel in diesel engine

fleet applications as a retrofit strategy. The reasons most often cited are the effectiveness of emission reductions, ease of transition to use, and minimal impacts on current operating equipment and vehicles. According to the National Biodiesel Board, nearly 1.2 million gallons of biodiesel fuel were used in 2004, and as of January 2005, there were more than 400 major



fleets using biodiesel, including all branches of the U.S. military, Yellowstone National Park, NASA, several state departments of transportation, major public utility fleets, various city agencies, and over 50 school districts (see www.biodiesel.org). D. Selection & Use Criteria

Available information from U.S. retrofit programs suggests that biodiesel blends do not appear to be incompatible with the use of DPFs and DOCs. Retrofit product manufacturers should be consulted before using any retrofit product with any biodiesel fuel.

Limited engine and vehicle testing suggest that compared to diesel fuel, the use of

biodiesel with DPFs, can extend the time to regenerate by up to 4 times. A DPF technology provider has verified the use of a DPF on B20 fuel (www.arb.ca.gov/verdev/verdev.htm).

In general, no engine modifications need to be performed or special fuel additives be

incorporated when using biodiesel up to a blend level of B20 that has been produced to the latest ASTM International specifications. Aside from the lack of need for engine modifications, modifying an engine may potentially create a violation of EPA’s engine/vehicle anti-tampering provisions of the Clean Air Act. The EMA, Stanadyne Automotive (a major supplier of diesel engine fuel system components), and most diesel engine manufacturers (including General Motors, Ford Motor Company, Detroit Diesel Corporation, Deere and Company, Caterpillar, Inc., Cummins Engine Company, and International Engine Company) limit engine warranty coverage to use of biodiesel blends of 5% or less. Choice of a biodiesel blend level (particularly if the biodiesel component is greater than 20%) should be made with care, particularly if the engines using it are likely to be operating in sub-freezing conditions that may contribute to fuel gelling of the biodiesel blending component. E. Costs

The cost of biodiesel can vary as a function of several factors, including the cost and type

of the biodiesel feedstock, specifics of the manufacturing process, production plant size, distance from production plant to blending and distribution points, the value of Federal and state production incentives and/or tax credits, and price supports to users. As such, a range of costs has been reported and can be found across the U.S. Data collected and developed by EPA show that in 2002, B100 could be purchased for $1.95 to $3.00 per gallon (or about twice the price of conventional diesel fuel), and that B20 was priced at $0.30 to $0.40 more per gallon than conventional diesel fuel, exclusive of any production or use incentives or price supports. A recent report prepared by the DOE-EIA analyzed the factors that comprise the cost of biodiesel production, and concluded that over the next few years, the cost of producing biodiesel was not likely to be competitive with that of petroleum diesel. Various production incentives, tax credits and price supports are likely to continue to create a pricing structure that can be favorable to biodiesel fuel users.



F. Product Quality, Delivery, Storage and Fueling

The diesel Fuel Injection Equipment (FIE) manufacturers and EMA have developed positions on the use of biodiesel fuels in the products of their respective member manufacturers. In 2000, the U.S. Army developed a Department of Defense Purchase Description (DOD PD) for the use of B20 in diesel-powered non-tactical ground vehicles.

The FIE manufacturers have documented a number of operating problems with biodiesel fuels (particularly those used before the ASTM specifications were created). The key concern of these manufacturers is related to resistance to oxidation. Aged or poor quality biodiesel fuel may contain organic acids, free water, peroxides and products of fuel processing that may attack engine and fuel system components leading to reduced service life. The DOE National Renewable Energy Laboratory (NREL) has conducted a nationwide survey of biodiesel quality, and found several B100 specification failures (four samples out of 27) for acid number, total glycerin or phosphorous. Further, of 50 samples of B20 taken nationwide, only 32 samples were actually found to contain about 20% biodiesel. Additives of the types used commercially in diesel fuel have been shown to provide improvements to the quality of biodiesel blends in areas such as detergency, water separation, cold flow characteristics, fuel system corrosion and foaming. Such additives should not be applied by fleet fuel users unfamiliar with fuels manufacturing and distribution.

In December 1998, the ASTM International Subcommittee D02.E0 approved the first provisional standard for the manufacture of biodiesel. Prior to that time, no common standard, or specification of characteristics important for reliable engine operation was available. The most recent specification for biodiesel was established in 2003 as “ASTM D6751-03a Standard Specification for Biodiesel Fuel (B100) Blend Stock for Distillate Fuels” and is to be used for blending with ASTM Specification D975 Grades 1-D, 2-D and low sulfur 1-D or 2-D diesel fuels. This current ASTM International specification includes test methods for establishing and measuring 35 individual biodiesel fuel characteristics or properties that are important to diesel engine/vehicle operation, including energy content, cetane number, cloud point, absorbed water, lubricity, viscosity, density, storage stability and flash point.

A specification for B20 is currently under development by ASTM International’s

Subcommittee D02.E0 as Work Item (WK) 6286. Specifications are under development for three grades of B20, with the biodiesel component of the blend conforming to the requirements of ASTM D6751, and the remainder of the fuel being a middle distillate grade diesel fuel conforming to ASTM D975:

• B20 (S15) with a diesel fuel component maximum sulfur level of 15 ppm. • B20 (S500) with a diesel fuel component maximum sulfur level of 500 ppm.

• B20 (S5000) with a diesel fuel component maximum sulfur level of 5000 ppm.

Given the variability in properties of biodiesel feedstocks, biodiesel should be purchased

in accordance with the latest ASTM International specifications. Biodiesel fuels should be



purchased from known, established suppliers that can attest to the quality of the biodiesel fuel product as being manufactured according to the latest ASTM International specification. The best place to have fuel quality verified (via testing) is as close to its final destination as possible, which is usually at the point of delivery to the user. Testing for conformance to key specifications at the point of delivery provides a minimal level of assurance that a quality product is being off-loaded into the user’s fuel storage equipment. Another means of assuring fuel quality is for buyers of biodiesel fuels to require that the supplier be BQ-9000 accredited by the National Biodiesel Accreditation Program (www.bq-9000.org). This program is a unique combination of the ASTM International specification for biodiesel (ASTM D 6751) and a quality systems program that includes storage, sampling, testing, blending, shipping, distribution, and fuel management practices. The accreditation process is comprehensive and includes a detailed review of the supplier’s quality system documentation, followed by a formal audit of its system. As of the writing of this report, there were two BQ-9000 accredited suppliers in the U.S., with additional suppliers involved in the accreditation process.

Clean, well-maintained and monitored equipment (preferably dedicated to exclusive use

of biodiesel fuels) should be used to store and dispense biodiesel fuels, to minimize the effects of water contamination, sediment pick-up, extended storage, temperature extremes and their subsequent problems. To minimize cold weather-related problems and gelling, biodiesel blends with diesel fuel should be stored in tanks that can ensure the fuel temperature will remain at least 5°F to 10°F above the cloud point of the blend.

The solvency action of biodiesel can loosen and carry fuel tank sediment that will collect

in fuel filters and clog them. Accordingly, fuel filters used on dispensers and engines should be inspected and replaced periodically. Such filters should be identified as being compatible for use with biodiesel fuels. Some fuel filter-related field problems with biodiesel blends were reported by a number of state DOT agencies. These filter problems declined or were completely resolved once the filters were replaced. Several state agencies avoided potential weather-related problems by discontinuing the use of biodiesel during cold weather periods.

Biodiesel, particularly at blend levels with diesel fuel of greater than B20, can be contaminated by growth of biological microorganisms. These microorganisms typically grow at the fuel-water interface and may not always be captured in fuel system filters. Should this occur, biocides are available to control growth. An excellent reference on this subject, Manual 47, Fuel and Fuel System Microbiology, is available from ASTM International, and provides a good understanding of fuel and fuel system biodeterioration, sampling requirements, test methods, and remediation practices.


VOLUME 2 – Section XII WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

XII. DIESEL FUEL EMULSIONS


Diesel fuel emulsions are blended mixtures of diesel fuel, water, emulsifying agents and

other additives, that reduce PM and NOx emissions, as a result of the added water. Addition of water to the emulsified fuel also reduces the energy content of the fuel, with corresponding reductions in fuel economy and engine power.

Courtesy of Lubrizol


Depending on the specific engine application and duty cycle, use of emulsions can result in NOx reductions of 5% to 30%, and PM reductions of 20% to 50%. These ranges of results have been demonstrated in several projects.

Use of an EPA-verified emulsified diesel fuel has been the subject of several studies, and for comparative purposes in several others. This emulsified diesel fuel is a combination of diesel fuel with 20% water by weight, and an "additive package" for stabilizing the fuel-water emulsion. A 2001 report prepared by Air Improvement Resource, Inc. under contract to the diesel fuel emulsion manufacturer undertook a comparative analysis of vehicle emissions using the emulsified diesel fuel and other diesel fuels. An eleven-engine database was developed to evaluate emissions from a baseline diesel fuel and the emulsified diesel fuel. The report’s conclusions show that generally, the emulsified diesel fuel provided consistent reductions for NOx and PM. HC emissions were typically found to increase slightly. NOx reductions ranged from 3% to 30%, and for most of the test cases, PM reductions ranged between 24% and 83%. This study also evaluated the emulsified fuel's performance in Sacramento and Los Angeles, where the selected fleet engines represented 25% of the centrally fueled highway vehicle fleets in both locations.

C. Status and Availability Currently, there is one technology provider of an EPA-and CARB-verified emulsified fuel (www.epa.gov/otaq/retrofit/retroverifiedlist.htm, and www.arb.ca.gov/diesel/verdev/ verdev.htm). The fuel product has been available from fuel suppliers in the general areas of the

©2005 Emissions Advantage, LLC 2.XII-1 November 18, 2005

VOLUME 2 – Section XII WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

West Coast, East Coast, Great Lakes area, and Gulf Coast. Emulsified fuels have been developed by other technology providers as well, but to date, have not been verified by EPA or CARB. D. Selection and Use Criteria

The University of Texas emulsified diesel fuel operational assessment identified a

number of "user issues", including: higher cost, engine manufacturer's reluctance to extend engine warranties when alternative fuel formulations such as diesel fuel emulsions are used, the perception of detrimental effects on certain type engines, fuel-water separation concerns, and perceived health and safety issues. These observations were based on interviews with various users at different test and project locations in the northeast, southwest, and west coast. Other reports, including the Brunswick Mine Study provide an evaluation of similar worker and potential customer concerns.

Since this technology has been introduced into commercial practice relatively recently,

there is a lack of currently documented information on longer term user issues such as storage stability of mixed fuel, and the affects of ambient temperature on emulsion performance

Diesel fuel emulsions generally do not appear to be a good application for vehicles or

equipment that operate primarily at high speed and/or high load. Care should be given to assessing the operating characteristics of the candidate vehicles/equipment. Where the operating modes tend to be at lower loads and/or speeds fuel emulsions have been used successfully

Typically, reduced power and fuel economy are related to the water content in the

emulsified fuel, but engine operating mode (full power vs. low power) also affects the degree of reduction. These impacts in terms of costs, tradeoffs and the related benefits of achieving emission reductions with emulsified diesel fuels are a function of the properties of the specific emulsified fuel formulation, vehicles and equipment the emulsion will be used in, and duty cycles of operation.

E. Costs

Available data suggest that the incremental cost of emulsions ranges from $0.25 to $1.00 per gallon of finished fuel product, depending on the volume purchased, time period for the fuel supply contract, and distance from the supplier to the user. F. Product Quality, Delivery, Storage and Fueling

Much of the same precautions and lessons learned from use of ULSD and biodiesel can be applied to diesel fuel emulsions. Since emulsions contain water, there are potential use and storage problems related to their water content. Establishment of good fuel handing and storage practices and use of segregated equipment will help to minimize such problems.

©2005 Emissions Advantage, LLC 2.XII-2 November 18, 2005

VOLUME 2 – Section XIII WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

XIII. DIESEL FUEL ADDITIVES A. Product Overview and Description

Fuel additives are chemicals added to fuel in very small amounts to improve one or more

properties of the base fuel. Detergents, corrosion inhibitors and storage stability improvers are examples of commonly used fuel additives. More recently, additive manufacturers have developed products that improve the engine combustion process and reduce emissions, without compromising or negatively impacting the properties of the base fuel. Some emission-reducing fuel additives employ fuel-borne catalyst (FBC) materials that use catalytic processes to reduce emissions during engine combustion.

A variety of different materials have been employed as FBCs including copper, cerium, cerium/platinum, iron/strontium, manganese and sodium. In the U.S. and Europe, the use of FBCs has been as part of a system with DPFs or DOCs. FBCs can also be used to facilitate regeneration of DPFs. As a general rule, the higher the level of FBC in the fuel, the more effective (i.e., the lower the exhaust temperature required to combust the soot) the catalyst’s performance. However, the higher the FBC level, the shorter the time interval before the DPF must be cleaned. One application required an FBC level of 30 ppm to 60 ppm for effective operation. Other applications require levels in the range of 8 ppm to 10 ppm.

Courtesy of Clean Diesel Technologies, Inc.


There are numerous manufacturers offering diesel fuel additives that are claimed to improve exhaust emissions, fuel economy, or both. In general, these improvements are claimed to be accomplished by improving combustion efficiency (by one means or another), resulting in reduced emissions. Additive manufacturers have developed proprietary formulations or fuel treatment processes, and license the process techniques/equipment and operating technology to small independent refiners that process the fuel into the finished product and sell it to users. In general, no engine modifications or changes to any other piece of fuel storage/dispensing or operating equipment are required to use these types of additives. Cetane number improvers are a major class of diesel fuel additives that promote emission reductions (primarily NOx). In a recent report, EPA presented the results of an analysis of the

©2005 Emissions Advantage, LLC 2.XIII-1 November 18, 2005

VOLUME 2 – Section XIII WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

impact of cetane improvers on NOx emissions. A statistical regression analysis found that if cetane improvers are added to a national average base fuel which would increase the cetane number by 5, NOx emissions would be lowered by a couple of percentage points.

C. Status & Availability

FBCs have been verified by EPA as part of both an FBC/DOC system and an FBC/FTF system for use in retrofit applications (www.epa.gov/otaq/retrofit/retroverifiedlist.htm). Several retrofit projects in the U.S. are using FBC additives, at least one of which is in conjunction with a DPF. Approximately 1,600 delivery trucks operated by Coca-Cola have used an FBC additive. D. Selection & Use Criteria

FBCs have also been sold as stand-alone products to be added to the fuel, even where

exhaust aftertreatment emission control technology is not utilized. In one study, more than 94% of the additive was found to be retained in the engine and exhaust system. This retention level increased to 99% when a DPF was used.

E. Costs

Available data suggest that the cost of the verified FBC additive is about $0.05 per gallon

of finished fuel product, for total fuel volume usage of about one million gallons per year. A general range of cost for non-FBC additives is between $0.04 to $0.10 per gallon of finished fuel product, depending specific product type and volume used. F. Product Quality, Delivery, Storage and Fueling

Progress is being made in developing precise on-board dosing FBC systems. However, in retrofit applications, particularly where a DPF system is involved, the more prudent course to avoid potential problems with imprecise on-board FBC delivery may be to use premixed fuel (e.g., the FBC is added to the fuel storage tank or a dispensing pump is used that adds the appropriate amount of the FBC when vehicle fueling occurs).

©2005 Emissions Advantage, LLC 2.XIII-2 November 18, 2005

VOLUME 2 – Section XIV WRAP OFFROAD DIESEL RETROFIT GUIDANCE DOCUMENT

XIV. OPERATIONS-BASED STRATEGIES In addition to retrofit technologies and fuel-based strategies, a number of other options exist to reduce emissions from existing diesel engines. These include:

• Idling Reduction. • Vehicle/Equipment Replacement.

• Engine Repower.

• Engine Rebuild.

• Repair and Maintenance.

These additional strategies are discussed below. A. Idle Reduction TECHNOLOGY OVERVIEW AND DISCRIPTION

Idle reduction can be accomplished in several ways for highway vehicles and off-road equipment. These strategies involve changes in vehicle/equipment operator behavior both with and without the use of idling reduction technology. While the current emphasis on approaches to idle reduction has centered on highway vehicles, some of these same approaches can also be used or adapted for off-road applications. CARB adopted a regulation requiring that starting in 2008, all new heavy-duty trucks sold or operated in California be equipped with either an automatic idle shut-off system (engine shut-off after five minutes of idling), certify to a 30 g/bhp-hr NOx idle emission limit, or employ cab comfort technologies that meet certain emission limits.

In June 2003, EPA undertook a major initiative to create the National Transportation Idle Free Corridors project as part of its SmartWay Transport Partnership. The objective of this project is to eliminate all unnecessary long-duration truck idling at strategic points along major interstate highways. The technologies described in the remainder of this section are those that have been employed in the SmartWay Partnership and in other retrofit projects. Their application to off-road equipment is highlighted, as appropriate.

Changes in vehicle/equipment operator behavior are easier ways to accomplish idle reduction than strategies that need technology solutions, and in fact, are usually the first method used in establishing an idle reduction policy.

As a rough rule of thumb, a modern diesel engine typically consumes about 1 gallon per hour while idling at 1,000 RPM,

©2005 Emissions Advantage, LLC 2.XIV-1 November 18, 2005


Behavior Modification Approaches to Idle Reduction

Behavior modification has its limits, however, since vehicle/equipment operators need to run accessories, namely climate control; heat is needed in the winter months, air conditioning in the summer months. By law, drivers of long-haul trucks are required to rest for at least 10 hours after an 11-hour shift. This translates into many hours spent resting in their cabs. When climate control is needed, an idle reduction technology is also needed. A number of mandatory and voluntary idling reduction program have been implemented in the U.S.

Operator behavior changes to reduce idling are generally applicable to off-road equipment as an effective means of reducing emissions. The technology approaches are generally more limited, however.

Technology Approaches to Idle Reduction

Automatic Engine Shutdown/Start-Up - Automatic engine start-up and shutdown

systems can control the engine on/off based on a set time period, outside ambient temperature or a preprogrammed parameter input by the driver (e.g. battery voltage). These systems automatically control engine starting and stopping for the purposes of reducing excess idle time and maintaining engine temperatures. Typical systems have three modes of operation: engine, cab comfort, and mandatory shutdown. Under the engine mode, the system monitors engine oil and battery voltage. If either drops below a set level, the engine is automatically started. Under the cab comfort mode, a cab thermostat starts and stops the engine to maintain the desired temperature. Under the mandatory shutdown mode, the engine will shut down after a given time (typically five or 15 minutes).

Direct-Fired Heaters - Direct-fired heaters (using vehicle fuel as the heat source) have

existed since the 1930s as auxiliary heat sources for automobiles and trucks. These systems can be used to heat both the sleeper cabin of a truck and the engine, or just one or the other. Direct-fired heaters can provide a quick payback for drivers since they are 80% efficient at converting diesel fuel to heat, compared to only 11% to 15% efficiency for engine idling that yields cab or sleeper heat, according to an Argonne National Laboratory report . A modern direct-fired heater uses about 1 gallon of fuel per 20 hours, according to one direct-fired heater manufacturer. One drawback to direct-fired heaters is their inability to supply cool air. Another drawback is the heaters' use of battery power to run blowers to move air. This amounts to electrical energy consumption one to two amp-hours, or about 15 amp-hours during a typical overnight stop.



Another heater plumbed into the engine's cooling system might consume another 9 amp-hours with its pump.

Courtesy of ACC

Auxiliary Power Units/Generator Sets - Auxiliary power units (APUs) provide electrical

power for vehicle/equipment “hotel loads” (power that is required when a vehicle is at rest and not needing the use of its prime mover for propulsion) such as climate control, power for appliances and lighting, battery charging and block heating to warm the engine coolant without idling. They consist of a small (typically, 2-cylinder) engine, usually diesel-powered, a generator set and a heat recovery system to provide electricity and heat. For air conditioning in truck applications, an electrically powered air-conditioner unit is normally installed in the sleeper, although some systems use the truck's air conditioning system. APUs also include a compressor, an alternator, and an inverter/charger. These units are fully integrated into the truck's climate control system. In addition, the inverter/charger allows the system to provide electric power to the cab and sleeper. However, APUs have a high associated cost and weight, up to 300 additional pounds counteracting some of the fuel economy gain. CARB has established emission limits for truck-mounted APUs. This has prompted the development of low-emission APU systems for these applications.

Shore Power Systems (e.g., Truck Stop Electrification) - “Shore power” systems are identical in concept to the auxiliary power supply systems that are used in recreational and commercial marine vessels to provide electrical energy to a boat so it does not have to operate its propulsion engine(s) while docked. In on-road applications, truck stop electrification systems essential provide the same function, allowing drivers to "plug in" trucks to operate necessary accessories without idling the engine. In some cases, a stand-alone system can provide climate



control directly to the sleeper portion of a truck. Options for shore power systems include stand-alone systems that are owned and operated by the truck stop, and combined systems that require both on-board and off-board equipment. In stand-alone systems, climate control systems are contained in packaging above the truck parking spaces. A hose from the HVAC system is connected to the truck window and a computer touch screen that enables payment. Stand-alone systems are owned and maintained by private companies that charge an hourly fee. To accommodate the HVAC hose, a window template must be installed in the truck. Shore power systems provide electrical outlets into which the trucks can connect.

To use shore power systems, the truck must be equipped with an inverter to convert 12-

to-120-volt, an electrical HVAC system and, of course, an extension cord. Inverters will also run down batteries unless they are regularly charged, which means plugging into shore power and/or running the engine for a while to let the alternator catch up with the demand. Inverters can help avoid idling, but not eliminate it. Invertors can, however, be teamed with generator sets to provide continuous power, and can also be used with heaters and/or coolers to provide climate control and power appliances. Truck stop outlets regulate the use and fees of these systems, while on-board equipment is owned and maintained by the trucking company. However, there is not currently enough commercial power available to run truck stop power grids, according to an analysis performed by the U.S. DOE Argonne National Laboratory. The U.S. already deals with brownouts and blackouts during the summer months, when electricity demand peaks. Drivers would plug in to run their air conditioners at this same time.

Courtesy of IdleAire

The Port of Seattle has installed shore power units for passenger cruise ships that can

“plug into” the city’s electric utility, which relies on hydroelectric power. This project, which is part of the West Coast Diesel Collabrative, is similar to the program initiated in the city of Juneau in 2001. Power will travel to the ship from a transformer designed to supply electricity to run all onboard services during the day-long calls. The project draws on the Juneau program experience, which currently outfits seven ships to use the city’s hydroelectric power.



To minimize the emissions generated from vessel’s on-board power generation, the Port of Los

y

ith

Angeles has designed and constructed a ship-to-shore power connection system for container vessels. When connected, the vessel is supplied with utility power and completelshuts down its on-board diesel-powered generators while at port. In comparison with a three mW container ship generating power either its diesel-powered generators, a vessel outfitted wa ship-to-shore power connection saw an average of a 95% reduction in NOx, SOx, and PM10.

MISSION REDUCTION

Table 14-1 provides a comparison of the idling emissions from a typical diesel engine (approx

Table 14-1, Idling Emissions from Diesel Engines and Idle Reduction Approaches

Emissions – grams/hour

E

imately 300 horsepower) and the various technologies described above.

Technology HC CO2CO NOx PM Diesel E 12.60 94.60 56.70 10,400 ngine 2.57 Direct-Fired Heater 0.17 0.44 0.26 N/A 1,456 APU 0.45 7.50 11.60 0.70 1,871 Shore Power 0.05 0.48 6.04 0.04 3,014 Behavior Modification 0 0 0 0 0



STATUS AND AVAILABILITY


One of the means to achieve behavior modification for idle reduction is to adopt a law or ordinan

st

e

Table 14-2, State and Local Idle Reduction Laws

State Maximum Idle Time

ce specifying idling time limits. Approximately half the states in the U.S. have passed laws or ordinances limiting engine idling time for various vehicles and offroad equipment. Mostates provide exemptions for emergency equipment, traffic or adverse weather conditions, and if the vehicle/equipment operator is resting in the vehicle. Idling limits in California, Montana, and Pennsylvania also apply to various types of offroad equipment. The Boston “Big Dig” and World Trade Center rebuild construction projects have incorporated idling restrictions. Tabl14-2 provides a list of state and local idle reduction laws

AZ 5 min (30 min for bus passenger com if >75°F) fort or 60 min/90 min CA 5 min CO 10 min in any 1 hour period CT 3 min DC 3 min (5 min if less than 32°F) GA 15 min (25 min if less than 32°F for passenger comfort/safety) HI No specified time (3 min for tart up/cool down or passenger loading/unloading) IL No specified time

MD 5 min MA 5 min MN 15 min/5 hours in residential areas (Owatonna); 5 min (St. Cloud) MO 10 min MT 2 hours in any 12 hour period (applies to diesel engines operating at times of poor air quality) NV 15 min NH 5 min if greater than 32°F (15 min 32°F to -10°F) NJ 3 min (15 min if stopped for greater than 3 hours, 30 min is permanently assigned) NY 5 min (3 min in New York City) PA 2 min or 0 min for layovers TX 5 min, April-October (30 min for bus passenger comfort or transit operations) UT No specified time (15 min – Salt Lake County) VA 10 min commercial or residential urban areas


Automatic Engine Shutdown/Start-Up - All electronically controlled diesel engines are

capable

e

Direct-Fired Heaters - Direct-fired heaters have been in use for many years, and are availab

of shutting down after a set period of time. It does, however, require the manipulation ofthe engine control module, which can be performed by the vehicle/equipment dealer, engine manufacturer, or vehicle/equipment owner at little cost. More complex, expensive systems aravailable through engine manufacturers.

le in configurations used to heat both the vehicle/equipment operator compartment andthe engine, or one or the other. Applications include many types of heavy-duty diesel vehicles and equipment (e.g., school buses, trucks, agricultural equipment) They are commercially



available from a number of manufacturers, but their market share as an idling reduction strais relatively low due to safety concerns, retrofitting costs, and reliability issues.

tegy

Auxiliary Power Units/Generator Sets - APUs and generator sets are proven technol l units are

hore Power Systems - Shore power systems for marine applications are available from several

at

r is

One manufacturer of stand-alone systems currently has installations in 23 truck stops across

SELECTION AND USE CRITERIA

The use of idle reduction technologies can help to reduce diesel emissions beyond the impact le


State and local governments interested in adopting regulations for time limit for idling have a s,

the

Wal-Mart has agreed to implement a nationwide idle reduction plan and pay fines to n

e

ogies and systems are available from several manufacturers. These commerciaavailable on new trucks as an option, keeping the battery and engine coolant warm and the cab cool so that drivers avoid diesel engine start-up problems. APUs have been installed on 1,400 locomotives throughout the U.S.

S manufacturers. Because of the limited market for truck stop electrification, this idle

reduction technology is not widely available to drivers. Currently, there are no truck stops thprovide “plug-in” power for drivers but demonstration projects are slated for Texas A shore power pilot project is currently underway in Sacramento, California, sponsored by the 49er Travel Plaza and the Sacramento Municipal Utility District. Under the demonstration, powefree and extension cords and equipment are available at the travel plaza. The outlets are rated at 20 amps, which can power an air conditioner, heater, microwave, stereo, TV, VCR, DVD player, refrigerator, coffee maker, stove, reading lamp, and battery charger to keep the DC power level up.

the country along the National Transportation Idle Free Corridor. Agreements with 3 major truck stop chains allow the manufacturer to be on track to equip another 600 locations from California to New Jersey. These systems are currently offered in Alabama, Arkansas, California, Georgia, New Jersey, New York, North Carolina, South Carolina, Tennessee andTexas. Two truck stops in Maryland are planned to be equipped with truck stop electrificationsystems. These are being funded with a CMAQ grant.

created by application of idle reduction regulations enacted in many states. As such, idreduction technologies have been used in retrofit projects throughout the U.S., and more particularly in states that have adopted time limits on engine idling.

wealth of examples to follow (see, e.g., Table 14-2, State and Local Idle Reduction Lawabove). In addition, EPA has worked with a number of agencies to developed idle reduction regulations and is developing a model regulation to help achieve some uniformity throughout country. settle violations brought against the EPA. The program entails implementing an idle reductioprogram at all of its facilities, whether state anti-idling polices are in effect or not. However, idlreduction programs do not have to driven by regulation to be effective. Many companies and fleet operators of all types have adopted idle reduction programs with “rules” that define



expectations from vehicle/equipment operators. Frequently, a reward/recognition system hbeen employed to acknowledge exemplary behavior and identify idle reduction “role models”Schneider National has instituted a voluntary idle reduction program that includes driver incentives. Through this program, Schneider claims that their idle times are among the lothe nation, at about half of the national average. The positive aspects of the program include: 1) low cost, 2) additional pay for the drivers, and 3) gives the driver the option to participate. Negative aspects of the program include: 1) requires engine recording, 2) difficult to managand 3) does not eliminate idling.

as .

west in

e,


Automatic Engine Shutdown/Start-Up - This technology can be applied to offroad equipm e

a

Direct-Fired Heaters - Direct-fired heaters have also been used in several types of offroad

Auxiliary Power Units/Generator Sets - APUs have been used as effective means to reduce es.

Shore Power Systems - Shore power systems are generally not “portable” in the sense that the

when

e

ent

STALLATION AND VEHICLE/EQUIPMENT MODIFICATION


Automatic Engine Shutdown/Start-Up - The simplest form of this technology is part of the eng

Direct-Fired Heaters - Heaters are typically installed in the tool or luggage compartment, behind

ent with electronically controlled engines and under conditions that are matched to thspecific duty cycle and job application. For example, automatic engine shutdown would not begood choice for use in a situation where the demand for engine power is intermittent and not very predictable or controllable, as in a diesel-powered compressor used to power air tools.

equipment, including farm tractors and large construction equipment.

idling in vehicles with large high-fuel consuming engines such as ships and locomotivAn APU is a good technology choice for these and other kinds of applications that need to supply power for hotel loads for extended periods of time.

y can be moved around easily to serve vehicles/equipment while performing their intended functions. These are “permanently mounted” systems that are used for occasionsvehicles/equipment need to provide power to operate onboard electrical needs when the prime mover is not needed for propulsion. Shore power units for marine applications are available in various power ranges to suit the power needs of the marine vessel being serviced. Units for largboats and smaller ships generally are custom configured for the application. Shore power technology can be used in non-marine offroad applications in a “docking station” arrangemwhere electrical demands are needed at the same time that the prime mover engines are needed for performing their function. IN

ine’s ECM. Therefore, the only necessary modification is to the programming in the module itself.

the cab across the frame rails, or on either side of the frame rails. The heaters should not be mounted on the vehicle /equipment, either near the fenders or on any other place with



excessive vibration, or directly to the engine. The heater should be mounted below the higpoint in the engine cooling system. Additional installation considerations include mounting in such a way that the exhaust pipe: 1) does not rest against or is directed toward any parts that mabecome damaged through excessive heat, 2) does not get clogged with debris, dirt and snow, 3) does not collect moisture from the combustion process without draining, and 4) does not face forward. For heaters that mount inside of the cab, special considerations must be made for thecombustion air intake, exhaust, and fuel inlet to the outside of the cab. Additional connections will have to be made to the vehicle/equipment cooling system, electrical system, and fuel systemto make the heater operational.

hest

y

Courtesey of Proheat

Auxiliary Power Units/Generator Sets - APUs are mounted externally as a side rail mount

he s

e

ere :

to the

operational.

(the most common), a long mount hidden behind the fairings, or behind the cab. When equipped to provide air conditioning, an electrically powered climate control unit (CCU) is typically installed in a convenient location near the operator’s cab, although some units use texisting air conditioning system. Installation can range from eight to10 hours, to one to five daydepending on the size, whether or not a CCU is included, and the installation location. Units typically weigh in the 300 pound range (and much heavier for locomotive applications), but arnon-invasive to the engine. APUs are generally mounted on the passenger’s side frame rail sincemost drivers sleep with their heads toward the driver’s side creating the quietest set-up. They can, however, be mounted on the driver’s side frame rail or behind the cab on top of the frame rails. Since most APUs for non-locomotive applications are designed to hang from the frame rails given their weight, special considerations must be accounted for when choosing a behind the cab mounting: 1) the location may interfere with the trailer when making turns, 2) the unit must be suspended from a custom built mounting frame, 3) custom fabricated brackets are required, and 4) is it the noisiest location given the close proximity to the driver’s head. Thare also several obstacles on the frame to overcome when suspending the APU from the side rail1) clearance around the existing fairing, 2) fuel tank, 3) battery box, 4) existing brackets in the intended mounting location, and 5) existing hardware in the intended mounting location. Necessary ground clearance is also required. Additional connections will have to be madevehicle/equipment cooling system, electrical system, and fuel system to make the APU



The CCU is typically installed under near or under the operator’s cab. Care mus

taken to ensurt be

e that there is ample space for electrical cables and ducting. CCU installation require s as s drilling several holes in the cab, mainly for plumping, electrical, and duct connectionwell as to ensure that there is an appropriate amount of return air.

Courtesy of Proheat

Shore Power Systems - Shore that a suitable location be identified

mount the electrical equipment, and an electrical power supply that is sufficient for the needs of all v

the mounted

ed

power systems requireto

ehicles/equipment that will be using the system. Truck stop electrification involves modifying trucks stops as well as the truck. At the truck stop, installation of ground electric outlets (GFCI and circuit breakers) are required at each parking space. It also involves retrofitting trucks with electric engine block heaters, an electric fuel heater, an electric cooling/heating device for the cab and electric automatic idle control. A relay to bypassbattery and activate the cab’s electric system is needed in addition to a surface or flush receptacle on the truck. In the case of stand-alone technology, a $10 window adapter is needfor the HVAC and computer hose. Shore power systems for large marine vessels require special design considerations to provide a match with the vessel’s specific electrical power needs. The port facility may also need to have moderate to substantial revisions to accommodate the electrical power supply needs for serving vessels.



FUEL REQUIREMENTS

Idle reduction technologies do not require any special diesel fuel use. Although they do reduce idling time, some technologies still require a fuel source, either gasoline or diesel. Direct-fired heaters and APUs consume significantly less fuel per hour than idling, between 0.03 and 0.3 gallons per hour. Some direct-fired heaters are also certified to operate on biodiesel. MAINTENANCE REQUIREMENTS

Automatic Engine Shutdown/Start-Up - There are no associated maintenance requirements for automatic engine shutdown/start-up.

Direct-Fired Heaters - Weekly maintenance is recommended for direct-fired heaters. his consists of running the heater a minimum of once a week to keep new diesel fuel in the

Failure to do this maintenance will result in a smoky start-up at the e heaters require this as a monthly maintenance. The

eater c

ld be performed at the conclusion of maintenance to “off”.

e. Oil and filter changes will be recomm

y

Theater’s critical components.

eginning of the heating season. Sombh an be run a minimum of 20 minutes each month to accomplish the same task. Annual maintenance is also recommended prior to each heating season including cleaning the heat exchanger, checking the heater’s exhaust system so that it vents properly, checking the electrical system for damage, cleaning the air intake, checking the fuel system for damages and checking

e condition of the batteries. Insufficient battery power will lead to the heater not operating thproperly. Finally, an operational test shounsure the heater cycles through “on” ande

Auxiliary Power Units/Generator Sets - APUs are essentially 2-cylinder diesel engines. Like any size diesel engine, they require periodic maintenanc

ended by the equipment manufacturer. Typically, this is in the every 150 hour range. Air and fuel filters will also require maintenance. Air filters will need to be changed when thebecome dirty and start to restrict air flow. Belts need to be checked on a regular basis and changed as needed, but typically last at least a year. The exhaust from the heat exchanger also needs to checked and cleaned a couple of times a year.

Shore Power Systems - Shore power systems are comprised of predominantly of heavy-duty electrical components requiring essentially no maintenance. Shore power truck stop electrification outlets are owned by private companies that regulate use. On-board equipment is owned and maintained by trucking companies.



COSTS

Table 14-3, EPA-Estimated Costs of Idle Reduction Technology

Idle Reduction Technology Cost

EPA estimated the cost of idle reduction technologies as shown in Table 14-3 below:

Automatic Shutdown/Start-up $7,000-$15,000 Direct-fired Heater $1,000 APUs and Generator Sets $1,500-$7,000 Shore Power $7,000-$15,000 B. Engine Repower

ECHNOLOGY OVERVIEW AND DISCRIPTION

Repowering is much like replacement, except that only the engine of an older vehicle

here the vehicle/equipment has a longer useful life than that of the engine in which it is used. In cases where st-based

trofit technologies, an engine repower may be the appropriate course of action. Diesel engine repowers generally come with several benefits, including:

creased horsepower and fuel economy.

reased engine life.

road projects.

to the price of a complete engine rebuild (cost-effective

T

/equipment is replaced. A repower is typically prudent for off-road equipment in casesw

ULSD or LSD is not available or feasible to enable the use of catalyre

• Possibility of in • Inc

• Familiar technology.

• New engine warranty.

• EPA-certified emission levels.

• Available funding for the repower (e.g. TERP or Carl Moyer).

• Claimable SIP credits.

• Opportunities to bid on state-required low-emission off-

• A new engine for closestrategy).



Courtesy of Caterpillar

MISSION REDUCTION

Emission reductions through the use of newer, cleaner engines have been accomplished by improvements in engine design, namely electronic controls and the fuel delivery system. Electronic fuel injectors have allowed OE manufacturers to adjust fuel timing independent of engine speed. This fuel injection scheme, as well as higher pressure injectors allowing for a more complete combustion process, combine to reduce emissions. Advances in combustion chamber design in addition to broader incorporation of turbochargers have also contributed to the emission reductions. One diesel industry source cites that newer on-road diesel engines have been attributed with an 83% reduction in PM and an 81% reduction in NOx since 1988. By 2007, new engines will provide a 98% reduction in both PM and NOx over a 1988 engine. NOx and PM benefits may be ontrolled en ine is replaced, a

otorious high emitter. Depending on the engine rating of the older, high-polluting equipment, ary from 25% to 75%. On later model repowers, however, there is

hows the offroad emission regulations for engines ranging between

E

achievable when an unc gnreductions in emissions may v

o PM benefit. Figure 14-1 sn50 and 750 hp.

Figure 14-1, Nonroad Emission Regulations

PM

175 < 750 hp

0 0 000

0.2

0.4

0.20.2

0.40.4

0.2 0.2

0 2 4

100 < 175 hp

50 < 100 hp

0.60.60.6

0.8

NOx NOx + HC NOx + HC NOx NOx0 0 0 02 2 2 24 4 4 46 68 810 10 6



In some instances, high rates of emissions reduction can be achieved. For example,

replacing a large 1975-1986 model year diesel engine, over 175 hp but less than 750 hp, with an engine meeting EPA Tier 1 standards would produce a 40% reduction in NOx and a 62% reduction in PM. Replacing the same engine with an engine meeting EPA Tier 2 standards would produce a 62% reduction in NOx and an 81% reduction in PM. Although repowering may be an effective method for reducing emissions, technical issues may make it impossible for some older, high-polluting engines, such as Tier 0 and Tier 1, to be replaced with newer, cleaner Tier 2 and Tier 3 engines (see “Installation and Vehicle/Equipment Modification” in this section). STATUS AND AVAILABILITY Engine replacement programs provide significant emission reduction benefits. As such, several engine manufacturers are providing engine repower kits and offer financing to do so. The kit offers compatible engine bases with existing engines, increased power, lower emissions, longer 9%

chnology and the engines meeting the current standards. The total incentive provided can not of NOx emissions reduced. All projects, including on-road,

ffroad and agricultural are subject to the maximum funding caps shown in Tables 14-4 and

Replacement Engine Maximum Incentive

life and lower owning and operating costs. One engine manufacturer cites a 50% to 7reduction in NOx with its repower kit. Repower programs have successfully been in place throughout California’s air pollution districts. The San Joaquin Valley and Tehama County Air Pollution Control Districts both offer an on-road, offroad and agriculture repower program. The incentives provided are intended to decrease the expense associated with the purchase of cleaner technologies. Therefore, the amount of money received depends on the price difference between the reduced-emission teexceed the value of $13,600 per ton o14-5 below:

Table 14-4, On-Road Heavy-Duty Vehicle Funding Caps

Existing Engine Pre-October 2002, Electronic Injection Post-October 2002, Electronic Injection $30,000

Pre-1987, Mechanical Injection Post-October 2002, Electronic Injection $30,000 Mechanical Injection OEM Mechanical Injection $25,000 Mechanical Injection Non-OEM Mechanical Injection $15,000

Table 14-5, Off-Road & Agriculture Heavy-Duty Vehicle Funding Caps

Off-Road Engine HP Maximum Incentive Agriculture Engine HP Maximum Incentive

50-99 $10,000 50-99 $5,000 100-150 $12,000 100-174 $10,000 151-250 $15,000 175-299 $15,000 251-300 $20,000 300-499 $20,000 301-400 $25,000 $30,000 Over 500 Over 400 $40,000

A

Where practical and appropriate repla d vehicles are e, pre-1984 should be rep el year eng s

SELECTION AND USE CRITERI

cement engines for onroa availabl model year engines laced with 1992 or 1993 mod ines. Thi



provides for a mechanical-to-mechanical swap. Although rarely done, post-1993 onroad engines can be repla e-1996 through 1998 offroad engines, are typically repowered with Tier 1 engines. Offroad Tier 2 e er, u 0 an r is most cost-effective in the oldest offroad engines, although from aprogram ewpoint, these ve d equipment are difficult to identi pieces o ent are typically an owner-operat very small fleet.addition, these fleets are often less likely to utilize major engine and vehicle/equipment vendors.

UIPMENT MODIFICATION

e ill

• EGR-equipped engines require cooling system engineering to install.

repower.

essary sensors and other materials are in hand when ordering a repower kit. Fleet technicians have identified cab and bulkhea m 21st Century electronic systems and have learned the programming tips to make sure that both computers, one for eac n

FUEL

fur level ith which it was certified. If ULSD is available or feasible, it should be considered as part of

the pro m ng LSD (less than 500 ppm sulfur) ould be considered.

ced with 2003 engines, an electronic-to-electronic swap. Tier 0 engines, pr

ngines are rarely, if ev sed to repower Tier d Tier 1 engines.

A repowe matic vi hicles an the most fy. Thesef equipm a part of or fleet or In

INSTALLATION AND VEHICLE/EQ Vehicle and equipment owners should consult OE manufacturers to ensure that the torquand power of the replacement engine is properly matched to that of the original engine. This wprevent damage to the vehicle or equipment. Other considerations involving a repower include:

• Engine control system integration (wiring challenges).

• Newer, cleaner engine availability varies.

• New engines do not always fit (physical constraints).

• May have to wait until the engine needs an overhaul to justify a

• Torque changes can require transmission changes.

• Frame support versus engine in frame.

Some fleets have developed a parts list to ensure all the nec

d odifications necessary to adapt 20th Century vehicles and equipment to

h e gine, work together.

REQUIREMENTS

The replacement engine should be operated with diesel fuel containing the sulw

gra . For offroad engines, if ULSD is not possible, usish



MAINTENANCE REQUIREMENTS

There are no additional maintenance requirements involved with replacement engines. rs should notice a decrease in maintenance costs with the newer,

chnologically advanced engine.

is needed again. Vehicles and equipment that operate up to 45,000 hours ould experience no major problems for at least seven or eight years.

OSTS

According to the Diesel Technology Forum, the cost to replace an older, more polluting etween $30,000 and $40,000. The costs will vary

epending on the degree of difficulty involved with the engine installation.

TECHNOL

arly replacement allows nd equipment fleets to replace the oldest and worst polluting vehicles/equipment with are designed with the most current emission-reducing technology. Typical benefits of

arly ve

• e).

• Potentially safer equipment.

•

in the emission inventory for SIP credits.

efer to have a newer vehicle/equipment then a repowered

Vehicle and equipment ownete

A new repower engine typically can be operated for 12,000 to 15,000 hours before

needing a rebuild, compared to a rebuilt engine that typically can be operated for 8,000 to 10,000 hours before rebuildingsh C engine with a 2002 model year engine is bd

C. Vehicle/Equipment Replacement

OGY OVERVIEW AND DISCRIPTION Early replacement involves retiring the oldest, most polluting vehicles or equipment before the time of their usual replacement cycle. In some instances, replacement may provide the most practical and cost-efficient method for improving emissions. Evehicle athose thate hicle or equipment replacement include:

• Reduced maintenance costs.

Improved reliability (decreased equipment downtim

Increased resale value.

• Potential for increased horsepower and fuel efficiency.

• Good for public relations.

• Lower emission vehicle/equipment placed

• Most fleet operators would pr

vehicle/equipment.



There are some potential issues involved with early replacement:

• May require scrapping the replaced equipment. • Grant funding may cover the full cost of the newer vehicle/equipment.

• Operating costs may be higher (e.g., if replacement uses an alternative fuel technology).

• Best suited to accelerate scheduled fleet modernization.

MISSION REDUCTION

nificant PM and NOx emission duction benefits, as a function of the model year of the equipment to be replaced (Refer to the

pre u n of emissions reduction benefits associated with emission standards). In addition, electronically controlled engines will also be mo u

STATU

essfully in large municipal ehicle rograms. For example, the

gram in Los Angeles County, California is comprised of three rt of Long Beach program and 3) retrofitting

p replacement effort as centives Program (EQIP). The program provided

ps for use in agricultural applications. In 2003, early

E Early vehicle/equipment replacement programs provide sigre

vio s Section B, “Engine Repower” for the discussio

re f el efficient providing for reduced overall fuel consumption.

S AND AVAILABILITY

Early vehicle/equipment replacement has been used succfleets with regular replacement programs and in transit bus pv

Gateway Cities Clean Air Proajor components: 1) fleet replacement, 2) Pom

heavy-duty trucks that are replacements or post-1994 trucks. The replacement portion of the program is targeted at pre-1983 trucks that serve the Port of Long Beach and the Port of Los Angeles. This voluntary program provides monetary incentives, which average $25,000 per truck, to purchase 1994 model year and newer trucks.

An example of an offroad application is the USDA irrigation pum part of its Environmental Quality Inpproximately 50% of the cost of irrigation puma

n $2.7 million in funding was available for replacing or repowering approximately 250 pieces of diesel-powered equipment by farmers in California's San Joaquin Valley.



SELECTION AND USE CRITERIA The oldest, most polluting engines and equipment should be the first to be replaced. Included in this grouping are two-stroke engines, which do not incorporate electronic controlsAdditionally, two-stroke engines typically do not accept retrofit technologies very well or aregood candidates for a repower. As a vehicle ages, engin

.

es generally pollute more. After all two-roke engines have been retired, the next oldest four-stroke engines should be replaced.

ch it

AINTENANCE REQUIREMENTS

There are no additional maintenance requirements with replacement vehicles and quipm the

/equipment.

ns

esigned for durability, as well as a long service life. As such, many gines were produced during years prior to EPA’s stringent emissions standards. In ain the maximum level of productivity from these engines, some fleets have found that

ngine

consider in cases where an engine repower is not itable.

st INSTALLATION AND VEHICLE/EQUIPMENT MODIFICATION There are no installation or vehicle modifications necessary with an early vehicle replacement. FUEL REQUIREMENTS The replacement vehicle/equipment should be operated with the sulfur level with whiwas certified. If ULSD is available or feasible, it should be considered as part of the program. Truck operators in the Gateway Cities Clean Air Program reported savings of approximately $1,700 per year on fuel with the newer replacement trucks. M e ent. In general, operators should experience a decrease in maintenance costs with newer vehicle COSTS As it is with the purchase of any vehicle or piece of equipment, cost will vary based on manufacturer, size and age. Obviously, a newer piece of equipment will cost more than older equipment but newer equipment will also provide a greater reduction in diesel engine emissioas it will employ current technology. D. Engine Rebuild TECHNOLOGY OVERVIEW AND DISCRIPTION Diesel engines are ddiesel enorder to ge rebuilding is a way to maximize the economic life of a piece of equipment or vehicle while improving emission levels from those of the original engine configuration/design. A low-emission diesel engine rebuild includes using components from emission-certified engine modelsto rebuild older engines. The low-emission rebuild can be accomplished for many engine families and is a cost-effective option tosu



EMISSION REDUCTION

Some of the earliest efforts applied to implementing low-emission engine rebuilds were a

ier 2 – 0.1 g/bhp-hr.

acturer, certified to the 0.1 g/bhp-hr PM emissions for the DDC UI and the DDEC II engine families, claimed to have the first EPA-verified rebuild kit. The

1980 ith EPA-certified retrofit technologies or have their

ngines rebuilt using certified low emission components at the time of the engine overhaul. The inte as only limited to 1993 model year and earlier buses operating in urban areas. Since 1999, between 10,000 and 42,0 n retrofitted or rebuilt as a result of the program. Also, New Jersey nd California have undertaken additional retrofit programs and guidelines to further reduce missio

lly

ose in

use equipment verified by EPA, which could have included a retrofit chnology (e.g. DOC) in conjunction with a rebuild kit. A complete listing of certified

equipment can be found in NESCAUM’s report prepared for the EPA, Heavy-Duty Diesel Emission Reduction Project Retrofit/Rebuild Component, EPA 420-R-99-014. Information on

result of the U.S. EPA’s Urban Bus Retrofit/Rebuild (UBRR) Program, which applied to 1993 model year and earlier transit bus engines (40 CFR Part 85 Subpart O). In order to be in compliance with the Urban Bus Retrofit/Rebuild Program equipment were required to be certified by the EPA. This program was oriented toward PM reductions, and provided for reductions under one of two approaches:

• Tier 1 – 25% reduction relative to the original engine certification. • T

One equipment manufMrebuild kit, which included a DOC, also reduces PM below the 0.1 g/bhp-hr standard, reduces CO and HC between 60% and 80%, as well as reducing opacity by approximately 80%. STATUS AND AVAILABILITY

The UBRR Program required that urban buses operating in metropolitan areas with populations over 750,000 to be equipped we

ntion of the program was to reduce the levels of PM in urban areas and w

00 eligible buses have beeae ns. In February 1998, New Jersey Governor Whitman signed an executive order to retrofit the state’s fleet of public highway heavy-duty diesel-powered vehicles. Up to 10,000 vehicles were retrofitted with DOCs certified under the UBRR Program. New Jersey estimatedthat 400 tons of VOCs and 130 tons of PM are reduced annually after the program was fuimplemented.

Offroad equipment built with engines for which UBRR rebuild kits are available can benefit from the use of those rebuild kits. In addition, some engine manufacturers offer engine rebuild hardware designed to reduce emissions from the engines to be rebuilt. SELECTION AND USE CRITERIA

Operators of the buses affected by the Urban Bus Retrofit/Rebuild Program could chofrom two compliance programs: 1) sets the PM emissions requirements for each bus engine the fleet which is rebuilt, or 2) sets out a specific annual target level for average PM emissionsfrom buses within the fleet. A key aspect to the program was the certified retrofit/rebuild equipment. In order to be in compliance with either Option 1 or 2 noted above, the operators were required tote



lo ission rebuild kits for other engines used in offroad applications can be obtained fromengine manufacturer representatives.

w-em

STALLATION AND VEHICLE/EQUIPMENT MODIFICATION

Typically, engine rebuilds include direct replacement parts for a given engine family. If the reb

l with f the

S

maintenance requirements. If the rebuild kit includes a DOC, some additional minimal maintenance may be necessa

t to be certified under the UBRR Program, the equipment anufacturer was required to guarantee that the equipment will be offered to affected bus owners

for $7,9ns

. Maintenance and Repair

ECHNOLOGY OVERVIEW AND DISCRIPTION

intaining and repairing a iesel engine has an effect on the combustion efficiency and can lower PM emissions (PM

is directly related to incomplete combustion), CO and unburned HCs. Performing roper maintenance and repairs, routinely, should also increase fuel economy, extend engine life,

e issues

•

• Clogged/worn fuel injectors.

IN

uild kit includes a DOC, some vehicle modification may be necessary (see Volume 2, Section II-E, “Installation and Vehicle/Equipment Modification”). FUEL REQUIREMENTS

The rebuilt engine should be operated with diesel fuel containing the sulfur levewhich it was certified. If ULSD is available or feasible, it should be considered as part oprogram. For offroad engines where use of ULSD is not possible, using LSD should be considered. MAINTENANCE REQUIREMENT Operators of engine rebuilds should experience no increase engine

ry (see Volume 2, Section II-G, “Maintenance Requirements”). COSTS In order for equipmenm

40 or less for 0.1 g/bhp-hr PM equipment or for $2,000 or less for 25% or greater reduction in PM. Costs for low-emission rebuild engine components used in offroad applicatioare specific to each engine manufacturer. E T One of the easiest and probably the least expensive way to reduce emissions from diesel engines is to ensure that they are properly maintained and cared for. Madgeneratedpreduce operating costs and eliminate any unnecessary maintenance. Several maintenanccan be attributed to an increase in diesel emissions:

• Restricted air filters.

Improper injection timing.



• Maladjusted fuel pump.

•

Excessive smoke can also result from tampering. Common areas for tampering are:

ation.

• Fuel injection timing modification.

• Excessive fuel flow rate.

M S

was available regardng the impact of good maintenance road equipment, several studies have been performed for on-road applications,

and provide a useful context for offroad equipm ple, in 2003, the Colorado School of Mines conducted a study in an attem in terms of emissions reductions through the use of dies nance. The only criterion for vehicle selection in this study e during acceleration. Twenty heavy-duty diesel trucks were te repaired, then subsequently retested with a goal to reduce the amount of visi oke. Trucks ranged in years from 1986 to 1999 (grouped as pre-1991 and 1991 m nd later) and gross vehicle weights between

were largely left to shop technicians. However, an inspection se ined to be a smoke emitter to check if 1) the intake was restricted or unctioning, 2) there was a

alfunctioning or maladjusted throttle control and 3) the fuel pump or injectors were

Malfunctioning turbochargers.

• Maladjusted governors.

• Malfunctioning throttle linkages.

• Poor diesel fuel quality.

• Smoke puff limiters.

• Fuel pump calibration modific

E IS ION REDUCTION

While limited information

practices on offent owners. For exam

pt to quantify the benefits el engine repair and mainte

was the visible emission of smoksted with a chassis dynamometer,

ble smodel year a

11,050 and 80,000 pounds. Decisions on what to repair quence was used once the truck was determ

the turbocharger was malfm



malfunctioning or maladjusted. Repairs to components affecting the air/fuel ratio were the most common since smoke is generated when the engine is operated at an air/fuel ratio above the

oke he

uced by 40%. The study also found that NOx emissions increased after repairs as the com ng the engine’s operating temp ers increased, they did not exceed the engine’s certified levels.

In a 1991, CARB estim aintained or

tampered with contributed to the high em issions accounted for 42% of HC, 56% of PM and 6% of NO nventory. To deal with the problem y diesel vehicles with excessive em during the inspection program were eligible to take . The program offered owners of fa d repairs. Sixty-nine trucks participated in the study resulting in an average opacity reduction of 43.3% (see Figure 14-2). The pri ,

sm limit. The most common repairs in the study were to fuel injectors, fuel pumps and injection timing. For the pre-1991 group, injector replacement and governor adjustment were tmost common repair; injector replacement was the most common repair on 1991 model year and later engines.

Table 14-6 shows the results of the study conducted on the 20 heavy-duty trucks. On

average, the study concluded that HC emissions were reduced by 78%, CO emissions by 17%, and PM was red

bustion efficiency of the diesel engine was increased, increasieratures and thus increasing NOx levels. Although the NOx numb

ated that heavy-duty vehicles that were poorly missions in California. These em

x of California’s emissions i, CARB conducted an initial inspection pilot program to identif

issions. Vehicles that failed a 35% opacity cutoff pointpart in CARB’s voluntary repair program

iled vehicles up to $1,500 in authorized dealer performe

mary causes of excessive smoke emissions were improper air/fuel ratio control settingsfuel injection timing problems and restricted air filters.



Table 14-6, Effect of Repairs on Emissions and Fuel Economy on Heavy-Duty Trucks

Emissions Reduction (% g/mi) Maintenance Performed HC NOx CO PM % mpg

Replace 1 injector 94.5 (0.7)* 57.4 77.69 14.8 Broken throttle pedal, reset pump timing (0.3) 15.8 (103.4) (0.27) (3.42) Replace 6 injectors 18.5 (5.4) 24.3 16.5 3.42 Major tune up, pump timing 7.7 (30.0) (29.1) 13.8 (0.74) Major tune up (50.0) (88.6) (48.3) 26.7 5.17 Reset tampered fuel pump (16.7) (27.2) 79.2 73.5 (4.53) Replace injectors, rebuild fuel pump (31.3) (121.7) (25.3) 13.4 (16.87) Replace fuel pump 2.2 7.1 0.3 5.5 0.51 Fuel pump, governor control (45.5) (110.5) (48.9) 27.3 0.58 Replace injectors 27.8 (11.7) 5.6 15.1 12.7 Replace injectors and camshaft 41.3 (49.7) 7.5 35.9 (1.17) Rebuild throttle linkage 0.0 (58.4) 3.9 34.7 11.84 Reset pump timing, repair throttle linkage 21.4 (92.1) (39.7) (1.5) (4.31) Replace injectors and thermostat 33.3 0.00 (3.3) 31.8 33.3 Replace 9 injectors 1.8 11.2 85.0 72.3 7.71 Replace cracked intercooler 0.84 14.8 (0.1) 15.5 15.4 Adjust fuel pump (9.4) 0.6 15.1 37.1 0.00 Replace injectors, pressure release valve 12.9 2.9 (15.9) (42.8) 0.68 Replace injectors, recalibrate fuel pump 43.5 2.0 38.8 34.2 1.75 Replace injectors 36.4 (45.8) (19.0) 22.9 (1.77) *Parenthesis indicates an increase in emissi re in fuel econom

Figure 14-2, Effect of Repairs on Opacity

ons or a duction y.



French researchers at the Institut National de Recherche sur les Transports et Leur Securite tested vehicles as received from owners and then again after being tuned to manufacturer’s specifications. As shown in Table 14-7, HC, CO, and PM emissions all decreased for diesel-powered vehicles. NOx emissions, however, increased. No reason was given for the rise in NOx emissions.

Table 14-7, Effect of Engine Tune-Up on Emissions on French Vehicles

In Chile, inspections of diesel-powered vehicles have been mandatory for several years,

specially for buses. The bus inspectesm

ion uses a dynamic test that determines the opacity of diesel oke; 2%

inspections are carried out by polemissions from several buses tested as part of a Chilean filed study. As part of the study, four buses had engines rebuilt to the manufacturer’s specifications. One bus was tested with a rebuilt engine, one was maintained in accordance with the manufacturer’s recommendations, one was maintained according to average maintenance standards and one received no maintenance. Some additional testing was conducted on a poorly maintained in-service vehicle without rebuilding the engine. As seen in Figure 14-3, PM emissions were several times higher for the engine in which no maintenance was performed and substantially higher for the poorly maintained in-service bus.

A well-maintained diesel engine should not emit excessive smoke and 1994 model year and later on-road diesel engines should not emit any visible signs of smoke. Due to the diesel engine’s durability, many older diesels are still on the road today, a number of which are poorly maintained. The presence of smoke often provides a negative connotation with the public. To counteract this, states have ini

opacity is allowed at idle, 30% opacity is allowed at full load. Selective roadside ice to control emissions levels. Figure 14-3 compares the

tiated state-wide inspection and maintenance (I/M) programs for diesel engines that incorporate smoke testing in an attempt to identify the gross emitters



Figure 14-3, Effect of Maintenance on Emissions of Chilean Buses

STATUS AND AVAILABILITY

The Clean Air Act Amendments do not require states to invoke an I/M program. Since

these programs are not required, EPA does not provide any specific testing guidance for these programs. However, the Society of Automotive Engineers (SAE) along with CARB have formulated a recommended test procedure for smoke testing. SAE J1667, the snap acceleration test, was issued in February 1996 as a standard procedure for testing smoke emissions from diesel engines. This non-moving test is performed using a smoke meter to measure the opacity of the smoke and is supposed to correlate to the state of engine maintenance or determine if any engine tampering has been performed. The test results are then classified as pass/fail, with standards set at 55% opacity for pre-1991 heavy-duty diesel vehicles and 40% opacity for 1991 model year and later vehicles.

In April 1997, EPA endorsed SAE J1667 to provide uniformity across all state-run smoke emission testing programs even though test methods vary across states. Currently, 16 states and 2 Canadian programs are in operation. Environment Canada’s The State of Heavy-Duty Vehicle Emission Inspection and Maintenance in Canada and the Unites States, as well as other sources,

rovide a list of states and the testing procedures used within those states. For on-road diesel e opacity, but can be set up in one of three ways:

pvehicles, all of the programs measur

Roadside Inspection – A sample of all trucks are selected at various locations for testing

.

Periodic Inspection – Registered trucks are inspected annually or biannually at an inspection facility.



Self-Certification Program – Designed for fleets that are allowed to conduct periodic testing at their own maintenance facilities and report the results to the state.

As mentioned above, a smoke opacity meter is used to measure smoke from diesel

ated emissions, like those measured in the Colorado School of Mines study, can be quan

pair was the evidence of visible smoke during acceleration. There is a relationship between smoke l PM emitted dy. As evident from the study, some of the trucks that displayed

gns of low smoke tested for relatively high levels of PM. This could indicate that smoke testing NSTALLATION AND VEHICLE/EQUIPMENT MODIFICATION

The repaired engine should be operated with the sulfur level with which it was certified. d be considered as part of the maintenance program. For

ffroad engines, if using ULSD is not possible, using LSD should be considered.

tine

ogram should be erformed. Diesel engines that emit excessive smoke often have problems with engine

ds guidelines can also be applied to offroad equipment as well.

engines. Regultified using an appropriate exhaust gas analyzer or on an engine dynamometer.

Appendix F, is a current list of portable in-field smoke opacity meters, chassis dynamometers and gas analyzer emission testing equipment, including advantages, drawbacks and their associated costs where available. SELECTION AND USE CRITERIA For the Colorado School of Mines study, the only criterion used to select vehicles for re

and PM, although the amount of smoke was not found to be a good predictor of tota according to the stu

sias part of a state I/M program may fail to identify a high PM emitter.

I No vehicle/equipment modifications should be necessary to institute an effective maintenance and repair program. FUEL REQUIREMENTS

If ULSD is available or feasible, it shoulo MAINTENANCE REQUIREMENTS Diesel engines should be maintained to the manufacturer's specifications. In addition,fleets need to ensure that engine emission controls have not been subject to tampering. Rouchecks of smoke levels as part of an overall vehicle/equipment maintenance prpperformance and frequently result in increased fuel consumption. I/M programs in the U.S. require at least an annual testing, but the EPA recommentesting at least twice a year. These



COSTS According to the Colorado School of Mines study, repair costs associated with diesel engine maintenance range from $85 to $2,053 with an average repair cost of $1,088. Average repair costs for pre-1991 trucks were $1,202 and $991 for 1991 model year and older trucks. The average cost of repairs according to a CARB study was $600.

67 A diesel smoke test conducted at a vehicle repair shop in accordance with the SAE J16standard typically costs approximately $100 or more.


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VOLUME 2 - WRAPAir.org...2005/11/18 · Engine Rebuild Engine Maintenance and Repair The material contained in Volume 2 will be updated periodically as new information becomes available