Examining Effects of Lubricant Composition

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Examining Effects of Lubricant Composition inEngine Component Systems in Pursuit of Enhanced

Efficiency under Environmental Constraints

Victor W. Wong

Massachusetts Institute of Technology

Cambridge, MA

2012 Directions in Engine-Efficiency and

Emissions Research Conference October 19, 2012

Dearborn, MI


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Friction/efficiency improvement in enginesrequire developments in multiple areas:

Mechanical Design,Operation:

- Power density- Sliding, rotational speeds- Component dynamics;

contacts and loading- Fluid-film vs metal-metal- Distortions, clearances,

film thicknesses

Material and SurfaceCharacteristics:

- Coatings, roughness,

textures, dimples, etc .

LubricantFormulation

- Base oil, additives:Advanced control ofin-situ propertiesand composition

Engine-ComponentLubrication/FrictionAnalysis and Design

1. Wear/Durability:- Film Thickness

2. Emissions/OilConsumption

3. Cost: Material,manufacturing,user operating cost

CONSTRAINTS:

Lubricant

appears tobe the keylink tomaterial &mechanicaldesign


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Project: Lubricant Formulations to Enhance EngineEfficiency in Modern Internal Combustion Engines

Cooperative Agreement #DE-EE0005445 (2011-2014)

Lubricant formulation is an essential strategy in overall friction reduction and engine efficiency improvement

LubricantFormulation

- Base-oil, additives:requirements,

optimization

Goal: 10%mechanicalefficiencyimprovement

DOE-NETL Current Program

Mechanical Design, component micro-geometries, operation:

Material and Surface Characteristics:

Among other approaches investigated previously/elsewhere:


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Base Oil

Additives(20-30%)

Our approach is to examine strategic control of lubricantproperties and composition in engine in subsystems

1. Base Oil: HCs providingbasic lubrication API Groups: I, II (lowS), III (low S, high VI),IV: synthetic, V other

2. Additives:- Detergents- Dispersants- Anti-Wear

- Anti-oxidants- VI and Friction Modifiers- Anti-foam- Pour-point depressants

- Extreme-pressure wear, etc


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1. Controlling oil/additive properties in local areas thatmatter most in specific engine subsystems

2. Interfacing with engine technologies that affect in-

situ effective lubricant properties in action

3. Optimizing lubricant formulation: the completepackage viscous/boundary friction, wear

4. Ascertaining compatibility with lubricant/additive-emission control system: lubricant/additives affect

fuel economy of engine operation beyond friction

Four lubricant technical themes that aim to worksynergistically to advanced engine technologies:


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situ effective fuel & lubricant properties in action






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Affecting: Additive effective concentrations in ring pack/valvetrainversus in sump

Residence time, oil supply/replenishment, vaporization

Overhead - Cam

Sump/Crankcase oil

LubeFilter

pump

TurboSeals

Valve stem seals ATS

Aftertreat - ment System

( Blowby PCV) Power -

CylinderLoop

MainLoop

Filter Loop

Ash and OilTo Exhaust

Oil Circulation

in Engine

Combustion

Valvetrain

Sump/Crankcase oil

LubeFilter

pump

TurboSeals TurboSeals

Valve stem seals ATS

Aftertreat - ment System

( Blowby PCV) Power -

CylinderLoop

MainLoop

Filter Loop

Ash and OilTo Exhaust

Oil Circulation

in Engine

Combustion

Lubricant behavior inside the engine: There are manyprocesses between oil in the sump and oil in the upper-ring-pack/ valvetrain that affect the oil and additive conditions


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Oil Supply:Jets, Splash

Oilaccumulationon pistonbevel/skirt

Ring-Pack oilaccumulation

Fuel dilution

Combustionproducts,acids,particulates

Vaporization

T r a n s p o r t u p a n

d d o w n

t h e

l i n e r

Hot

Cooler

Mixing,entrainment,degradation ofoil within ring-pack, piston

Power Cylinder Transport Loop

Oil properties at critical surfaces are different from sump composition

(NOT TO SCALE)


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Changes of lubricant species also bylubricant-surface interfacial processes

Adsorption onSurfaces

Tribochemical

Wear-filmproducts

ProcessesAnti-wear film formation

Wear process

Anti-Corrosion, DepositsFriction Modification

SpeciesZn, B, S, P, compounds

Fe, Al

Ca, MgOrganic molecules -GMO


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L i n e r

O i l F i l m

Poor OilRefreshment

TDC of TopRing

TDC of OCR

PISTON

OilSupply

Vaporization

{

Vaporization Processes:

{Vaporizationof oil fromring-packand pistoncrevices

convection

s

: oil vapour surface density

: oil vapour free stream density

( ) j j m j j jMgen h S s=

Heat transfer analogy:

Mutli-Species: by carbonnumbers

In various regions: crown land,ring-pack, piston crevices, and

on liner


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Ring Pack Sampling System

Sloan Automotive Laboratory


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Top Ring Zone Enrichment

Sloan Automotive Laboratory

All metals are concentrated in the top ring zone samples Degree of enrichment is different for each element Lowest enrichment found for ZDDP elements

Enrichment Factor =

Concentration ofelement in ring-packzone relative toconcentration ofelement in sump


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Bottom Line:

Opportunities in optimizing the effectivelubricant composition in operation at themost critical locations for bestperformance at surfaces boundaryfriction, wear, detergency that tailor tolocal conditions at engine subsystems

1. Controlling oil/additive properties atcritical surfaces in local areas in specific

engine subsystems (valvetrain, pistonassembly, bearings..)


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situ effective lubricant properties in action






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Effects of Temperature Sensitivity of Viscosity

Oil Temperature (Deg C)

BDC TDC Approximate Position on Liner

Ideal viscosity

Ideal viscosity should be low at mid-stroke and high at end strokes:either via lubricant design or component thermal management

0

3

6

9

12

15

18

90 110 130 150 170 190 K i n e m a

t i c V

i s c o s

i t y c

S t

15

Viscosity Index: In-situ Lubricant Properties Control


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Strategic Application Of ThermalBarrier Coatings (TBC)

Applied to mid-stroke to not affectlubricant properties at TDC or BDC


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100

110

120

130

140

150

160

170

180

190

200

1 2 3 4 5 6 7 8 9 10

L i n e r T e m p e r a t u r e

[ C

]

Liner Segment

Liner Temperature with Coating On Segments 4,5,6Baseline - No Coating 0.5 MM Coating 0.75 MM Coating 1 MM Coating

1.5MM Coating 2 MM Coating 3 MM Coating

Baseline

TDC BDC

TBC Region

Increasing TBC Thickness

17


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0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10

L u b r i c a n t V i s c o s i t y

[ c S t

]

Liner Segment

Local Viscosity of 15W-40 with Coating on Segments 4,5,6Baseline - No Coating 0.5 MM Coating 0.75 MM Coating 1 MM Coating

1.5MM Coating 2 MM Coating 3 MM Coating

TDC BDC

Increasing TBCThickness

Baseline

TBC Region

18


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0

2

4

6

8

10

12

14

1 2 3 4 5 6 7 8 9 10

K i n e m a t i c V i s c o s i t y

[ c S t

]

Normalized Liner Position

Lubricant Viscosity verus Liner PositionIdeal Baseline - No Coating 1 MM Coating

BDCTDC

Baseline-noCoating

IDEAL

TBC

Gains

19


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0%

5%

10%

15%

20%

25%

30%

35%

1 2 3 4 5 6 7 8 9 10

P e r c e n t D e c r e s e i n S e g m e n t F r i c t i o n

Liner Segment

Percent Decrease in Friction for TBC Applications1mm Coating, 15W-40 Reference Oil

Coating on Segments 4,5,6 Coating on Segments 4,5,6,7 Coating on Segments 4 Though 10

Target Zone forMaximum FMEP

Reduction

20


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Bottom Line:

Potential opportunities in further viscosity-temperature sensitivity (VI improvers)optimization in base oil that matchadvanced engine technologies

2. Interfacing with engine technologies thataffect in-situ effective fuel & lubricant

properties in action


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Stribeck Diagram

From e.g. 2011-01-2134 Nattrass, S.R et al

ff dd h ff d ff


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Different additives show varying effects to differentengine subsystems in split valvetrain lube system

Additive types and concentration

From e.g. 2011-01-2134 Nattrass, S.R et al Ford Zetec 2l I4 gasoline


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Phase 1: Investigate the ideal lubricant formulations tailored to each major

engine component subsystem for the best performance

Modeling the effects of lubricant parameters on friction and wear forsubsystems

Parametric experiments to determine lubricant & additive effects onsubsystems

Phase 2, 3:

Develop composite lubricant formulations, tradeoffs and implementationstrategy for optimal lubricant formulation for the overall engine.Demonstrate the mechanical efficiency improvement. Determineimpact if any on emission control system.

Program Phases and Major Tasks:

k l b ff


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Major tasks to examine lube composition effectsModeling the effects of lubricant parameters on frictionand wear for subsystemsExtend single-component models to include lubricant compositionvariations, including additives. Semi-empirical models on boundary-friction vs additives

Develop and apply a lubricant compositional model to the power

cylinder and valvetrain subsystems

Parametric experiments to determine lubricant & additiveeffects on subsystems

Lubricant sampling and composition measurements

Lubricant and additive effects on piston assembly and bearings

Lubricant and additive effects on cam/valvetrain friction

L b i i Ci i d S b


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Lubrication Circuit and SubsystemSeparation

Overhead camshaftconfiguration enablesthe separation of thevalvetrain and

crankcase lubricationcircuits

Dedicated torque

sensor to determinecamhaft torque andpower

Kohler


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Separate engine and valvetrain rigEngine to be operational end of Oct

AC InductionMotor

InlineTorquemeter

CylinderHead

F l b i h i l h h i k


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Different lube additives (ash) affect both engine and DPF


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Different lube additives (ash) affect both engine and DPFdifferently and will have both emission and efficiency impact

Lubricant additives composition affects ash properties and pressure drop

Ca-based ash shows much larger effect on pressure drop than Zn ash

0.0

0.5

1.0

1.5

2.0

2.5

3.0

3.5

0 5 10 15 20 25 30 35 40 45

P r e s s u r e

D r o p

[ k P a

]

Ash Load [g/L]

Mg (o)

Flow Bench @ 25 C, Space Velocity: 20,000 hr -1

CJ-4

Ca

ZDDP ( )

Mg & ZDDP (x)

Ca + ZDDP

1.5 g/L 15 g/L

(Detergent)

(Anti-wear)

S


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Summary Opportunities exist in optimizing the effective lubricant

composition in operation for best performance at

surfaces boundary friction, wear that tailor to localconditions at engine subsystems

There are potential opportunities in further viscosity-

temperature sensitivity (VI improvers) optimization in base oilthat match advanced engine technologies

Convergence of lubricant chemistry and mechanical

analysis will be helpful in developing and applyingadvanced lubricants for efficiency improvements

Modeling and tests on lubricant composition effects on

friction are challenging but will extend efficiency frontiers


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Thank you!


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Supplementary slides


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Project: Lubricant Formulations to Enhance EngineEfficiency in Modern Internal Combustion Engines

DOE-NETLCooperative Agreement #DE-EE0005445

with

Massachusetts Institute of TechnologyCambridge, Massachusetts

Prof. Wai K. ChengPrincipal Investigator

Dr. Victor W. Wong and Dr. Tian TianCo-Investigators

Kick-off MeetingNovember 15, 2011

Washington DC


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The overall program goal is to investigate, develop,

and demonstrate low-friction, environmentally-friendlyand commercially-feasible lubricant formulations thatwould significantly improve the mechanical efficiency ofmodern engines by at least 10% (versus 2002 level)without incurring increased wear, emissions ordeterioration of the emission-aftertreatment system

The specific project objectives include identifying thebest lubricant formulations for individual engine

subsystems, identifying the best composite lubricantformulation for the overall engine system, anddemonstrating the mechanical efficiency improvementfor the optimized lubricant formulation via enginetesting

Program Objectives:


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The overall program goal is to investigate, develop,

and demonstrate low-friction, environmentally-friendlyand commercially-feasible lubricant formulations thatwould significantly improve the mechanical efficiency ofmodern engines by at least 10% (versus 2002 level)without incurring increased wear, emissions ordeterioration of the emission-aftertreatment system

The specific project objectives include identifying thebest lubricant formulations for individual engine

subsystems, identifying the best composite lubricantformulation for the overall engine system, anddemonstrating the mechanical efficiency improvementfor the optimized lubricant formulation via enginetesting

Program Objectives:


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Definition of Program Phases/Budget Periods, Tasks, andSchedules

Program Duration: October 1, 2011 September 30,2014 (36 months)

Budget Period 1 = Phase 1: October 1, 2011 January 15, 2013 (Duration: 15.5 months)

Budget Period 2 = Phase 2: January 16, 2013 January 15, 2014 (Duration: 12 months)

Budget Period 3 = Phase 3: January 16, 2014 September 30, 2014 (Duration: 8.5 months)


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Task 1.0 Project Management and Planning (continuous)

Phase 1: To investigate the ideal lubricant formulations tailored to eachmajor engine component subsystem for the best performance

Task 2a: Modeling the effects of lubricant parameters on friction and wear for subsystems

Task 3: Develop experimental/analytical lubricant test parameters in consultation withteam participant(s) from lubricant/additive industry

Task 4a: Parametric experiments to determine lubricant & additive effects on subsystems

Task 5a: Data analysis, interpretation, and iteration between modeling and testing

More details discussed for each task after overview of work planned for eachPhase

Identification of Tasks in Each Phase:

Identification of Tasks in Each Phase (continued):


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Phase 2: To investigate composite lubricant formulations that retain most of the frictionalbenefits for the subsystems identified in Phase 1. Identify the tradeoffs andcompromises necessary for an optimal composite lubricant formulation for the

combined subsystems

Task 2b: Additional Modeling the effects of lubricant parameters on friction and wear forsubsystems

Task 4b: Additional parametric experiments to determine lubricant & additive effects onsubsystems

Task 5b: Additional data analysis, interpretation, and iteration between modeling andsubsystems

Task 6: Modeling the effects of lubricant formulations with local variations in chemistry in

overall engine with combined subsystems

Task 7: Engine experiments to determine lubricant and additive effects for the entireengine system

Task 8: Develop and design the enabling lubricant-handling technology and configurationin the engine, so that the best formulations can be implemented



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Phase 3: To demonstrate the mechanical efficiency improvement for thebest optimized lubricant formulation in an actual engine over a range ofoperating conditions that both reflect those in standardized industryprotocols and other driving conditions

Task 9: Demonstrate in an actual engine the quantitative improvements inthe mechanical efficiency the best formulations from this study, ina production engine

Task 10: Evaluations of the impact on emission-control systems

Task 11: Technology transfer and interfacing with users and researchers



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Task descriptions:

Task 1.0 Project Management and Planning

Task 1 will be a continuing effort throughout theprogram for monitoring the project status,tracking technical and financial reporting asrequired, and for reviewing and revising the on-going project plan with DOE periodically, as

required

Task descriptions (continued):


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Task descriptions (continued):

Task 4.0 Parametric experiments to determine lubricant &additive effects on subsystems (Phase 1 + 2)Iterations between experiments and modeling (Task 2) will be expected

Four sub-tasks:

Sub-task 4.1: Engine installation

Sub-task 4.2: Lubricant sampling and composition measurements

Sub-task 4.3: Lubricant and additive effects on piston-ring-liner/crank friction

Sub-task 4.4: Lubricant and additive effects on cam/valvetrain friction

T k d i ti ( ti )


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Task descriptions (continue):

Task 3.0 Develop experimental/analytical lubricant testparameters in consultation with team participant(s) fromlubricant/additive industry (Phase 1)

(a) Base oils: oils with different high/low shear viscositycharacteristics, viscosity modifiers,

(b) Other additives: boundary friction modifiers, anti-wear agents, detergents, anti-oxidants, and non-traditionaladditives such as nano-particles particularly thosecarbon based particles that do not further add to ashemissions to the aftertreatment system. Actualformulations will be discussed with lubricant/additivepartner

k 0 d l [ h ]


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Task 4.0: Engine experimentation details: [Phase 1]

Engine criteria:

1. Diesel, as proposed, where lubricant contaminationfrom combustion more severe.

2. Small, easy to work with, saves fuel when studyinglonger duration operation and cost of operation

3. Configuration common to most vehicles

4. Domestic manufacturer preferred due to easy oftechnical support and potential participation

Kohler diesel with belt driven overhead cam,

inline 2, 3, or 4 cylinders


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Lubrication System: Kohler KDW702, 1003, 1404 dieselwith overhead cam


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Kohler KDW 702 twin-cylinder diesel engine specifications

T k 4 0 L b i d f i i


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Task 4.0: Lubricant and friction measurements

Separation of lubrication loops for individual subsystemsalso allows lubricant formulation changes with ease

1. Friction changes due to lubricant formulations forindividual subsystems

2. Degradation and lubricant property changes versus

time against friction changes3. System allows for determination of the sensitivity of

individual subsystem contributions (overheadvalvetrain, crank, piston/ring /liner) to friction using

different lubricant formulations4. System allows for closed loop or open loop lubricant

flow to study effects of lubricant property degradationor contamination on friction

Task descriptions (continue): [Phase 1]


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Task 5.0 Data analysis, interpretation, and iteration

between modeling and testing

Results from the extensive modeling effort and the

large number of tests involving the matrices of test andmeasured parameters will be analyzed and correlated

Guidelines for formulation changes to realize furtherfriction improvements will be developed, newformulations proposed and tested, in an iterativeprocess



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Phase 2: Identify the tradeoffs and compromises necessary for an optimal

composite lubricant formulation for the overall engine with thecombined subsystems

Task 2b: Additional Modeling the effects of lubricant parameters on friction and wear forsubsystems

Task 4b: Additional parametric experiments to determine lubricant & additive effects onsubsystems

Task 5b: Additional data analysis, interpretation, and iteration between modeling andsubsystems

Task 6: Modeling the effects of lubricant formulations with local variations in chemistry inoverall engine with combined subsystems

The models developed in Task 2.0 can be applied to study the overall enginewith all the subsystems combined. Analytically, via the modeling, variousconcepts of controlling lubricant properties can be explored

Frictional benefits using an optimized lubricant formulation will be compared tothe best formulations for the subsystems individually.



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Phase 2 (continued): Task 7: Engine experiments to determine lubricant and additive effects for the

entire engine system

Task 7 deals with the pragmatic issue of actually implementing the laboratory optimallubricant formulation strategy. The best lubricant formulation will probably depend onhow the lubrication system will be designed.

There are four major configurations:

(a) One fluid with best compromised formulation: Fully segregated, no mixing. Non-optimal, but pragmatic. There will be differing degradation rates in each subsystem

(b) One fluid: Full mixing conventional configuration, which is the prevalent lubricantformulation strategy. Non-optimal

(c) Two fluids, but only one needs to be changed during routine engine operation. The otherlubricant formulated to last until major engine overhaul.

(d) Other means of controlling lubricant properties and their effects: (i) lubricant speciesremoval stations: chemical or particle sequestration, (ii) chemical or active speciesperiodic release, (iii) oil conditioning of lubricant flow between subsystems



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Task 8.0

Develop and design the enabling lubricant-handlingtechnology and configuration in the engine, so that thebest formulations can be implemented

Addresses the pragmatic issue of how to implement thebest formulation tested in a laboratory configuration

Investigate and develop practical means to enableimplementation of the best formulation in an engine

Demonstrate potential feasible means for use in thefield



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Phase 3: To demonstrate the mechanical efficiency improvement forthe best optimized lubricant formulation in an actual full-sizeengine over a range of operating conditions that both reflect thosein standardized industry protocols and other driving conditions

Task 9: Demonstrate in an actual engine the quantitativeimprovements in the mechanical efficiency the best formulationsfrom this study, in a production engine

The demonstration will last a sufficiently long duration to illustrate thesatisfactory deterioration rates, if any, of the lubricant formulation withinmajor oil drain intervals, and durable engine performance with acceptablewear



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Task 10: Evaluate the impact of the best friction-reduction lubricantformulations on emission-control systems

Focus on Diesel particulate filters (DPF)

Use accelerated ash accumulation test rig at MIT using the bestcandidate low-friction oil formulations

Evaluate back pressure build-up, by passive or activeregenerations, and DPF performance, of the candidate formulation

Task 11: Technology transfer and interfacing with users & researchers

Throughout program With DOE-NETL With public at large via conferences, theses, publications With working team supporters in industry oil, additive, engine co.

D li bl


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Deliverables

Summary of accomplishments and project work reportwill be prepared for inclusion in the annual VehicleTechnologies programmatic progress report. Report willbe due by October 31 of each year

Upon completion of a milestone, a brief milestone reportwill be provided to verify and document the completionof the milestone

The Project Management Plan will be updatedperiodically as needed. Updated plans will be submittedto NETL


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Documents

Examining Effects of Lubricant Composition