Diesel Engine for Passenger Car and EU6: Entirely ... - Green …bioage.typepad.com/greencarcongress/docs/Tech_Paper_Vienna_20… · 27-04-2007 · The future of the Diesel engine

- 1 -

28. Internationales Wiener Motorensymposium 2007

Stephan Bauer, Dr. rer. nat. Hong Zhang, Dr.-Ing. Andreas Pfeifer, Dr.-Ing. Klaus Wenz-lawskiSiemens AG, Siemens VDO Automotive, Regensburg

Diesel Engine for Passenger Car and EU6: Entirely System Approach for Development of Fuel Injection System, Air/EGR Path and Emission Af-tertreatment

AbstractThe future of the Diesel engine beyond EU5 will, more than in the past, rely on combining both, engine measures to reduce pollutant emission and efficient exhaust aftertreatment in a sensible manner. To find a good balance between emissions, fuel consumption and minimal cost, both measures pose great technical and economical challenges.

This presentation will discuss whether the alternative combustion processes, already focussed on for EU5, like HCCI, will be robust enough for serial production or whether the conventional Diesel combustion can be optimized sufficiently by more comprehensive control.

A modular, coordinated "engine-emission-management" concept will be necessary, where different modules are interchangeable. A interlinked control of rail pressure, boost pressure and EGR control with temperature management, as well as De-NOx control will be mandatory. The control of the combustion via the cylinder pressure signal may be beneficial in some cases and has to be considered in the overall system concept.

Only an integrated system approach is useful to find the most cost effective solution.

1 IntroductionDiesel engines currently cover a market share of approximately 49% of the 19 million newlicensed passenger vehicles in Europe. The growth rate of this share in the last 5 years exceeded 40%. This remarkable development was mainly facilitated by the application of flexible injection systems, like Common Rail. This leads to a change from the well known paradigm of the lame, loud and stinking Diesel to a gasoline-like engine with an outstan-ding torque.

To maintain the competitiveness of the Diesel engine in the future, the costs, which will be essentially determined by the emissions legislation, must be kept as low as possible. Especially the necessary effort for exhaust after-treatment will become with view to costs a big challenge for developers.

The EU6 emissions limits, obligatory in force from 2014 (Figure 1), in comparison to today's standards effect:

• a reduction of the PM emissions of 80 %• a reduction of the NOx emissions of 70 %• an extension of the operational performance to 160000 km, for which the vehicle

manufacturer has to warrant the compliance to the emissions limits • that passenger cars with a GVW above 2500 kg cannot be registered as LDV

anymore

- 2 -


Figure 1: PC market trend and European emission standardsIt will not be possible, to achieve the ACEA-CO2 targets without a high share of Diesels in the passenger car fleet. These targets require for the EU6 introduction a reduction of the CO2 output of roughly 35% with reference to the year 2005. The average level 2006 in Europe was approximately 170 g/km [1]. This challenge can only be solved by a combined optimisation of combustion process, air supply, fuel injection system and exhaust gas after-treatment. Figure 2 provides an overview of the interrelations.

Figure 2: Systematic optimisation approach

Europe

Diesel49%

Gasoline51%

19 Mill.

2006

0111

06 11

6.7

9.49.9

+42%

+5%

Source: CSM 2006

NOx (g/km)0.0 0.1 0.2

PM (g

/km

)

0.00

0.02

EU5EU5EU6EU6

0.04

-28 %

-68%

-80%

186170

140

120100

120

140160

180

200

2000 2005 2010Fl

eat a

vera

ge C

O2

emiss

ion

[g/k

m]

ACEAcomitment

-35%

Europe

Diesel49%

Gasoline51%

19 Mill.

2006

0111

06 11

6.7

9.49.9

+42%

+5%

Source: CSM 2006

Europe

Diesel49%

Gasoline51%

19 Mill.

2006

0111

06 11

6.7

9.49.9

+42%

+5%

Source: CSM 2006

NOx (g/km)0.0 0.1 0.2

PM (g

/km

)

0.00

0.02

EU5EU5EU6EU6

0.04

-28 %

-68%

-80%

186170

140

120100

120

140160

180

200

2000 2005 2010Fl

eat a

vera

ge C

O2

emiss

ion

[g/k

m]

ACEAcomitment

-35%

NOx (g/km)0.0 0.1 0.2

PM (g

/km

)

0.00

0.02

EU5EU5EU6EU6

0.04

-28 %

-68%

-80%

NOx (g/km)0.0 0.1 0.2

PM (g

/km

)

0.00

0.02

EU5EU5EU6EU6

0.04

-28 %-28 %

-68%

-80%

186170

140

120100

120

140160

180

200

2000 2005 2010Fl

eat a

vera

ge C

O2

emiss

ion

[g/k

m]

ACEAcomitment

-35%

Air path

OEM

FIE Supplier

Accurate control of manifold air pressure àModel based strategyAccurate control of fresh air and EGR àModel based strategies

cooled EGR turbo chargingvariable swirl / number of valves

Engine Designcombustion chamber design

compression ratio

Fuel Injectionvariable injection pressure

multiple injection flexibilityminimal injection quantities

Small injection tolerances(cycle/cycle;shot/shot)

robustness

Exhaust Gas Aftertreatmentoxidation catalystParticulate filterNOx trap respectively SCRAfter-treatment and regeneration management

Diagnostics / Limp homeEOBD-functionality Monitoring concept

Other functionalities

Engine management

State of engine operationTorque coordination / injection strategy

Idle speed controlaccurate control of injection amount and timing phasing

Air path

OEM

FIE Supplier

OEM

FIE Supplier






compression ratio


compression ratio

Fuel Injectionvariable injection pressure

multiple injection flexibilityminimal injection quantities

Small injection tolerances(cycle/cycle;shot/shot)

robustness

Exhaust Gas Aftertreatmentoxidation catalystParticulate filterNOx trap respectively SCRAfter-treatment and regeneration management



Other functionalities

Engine management

State of engine operationTorque coordination / injection strategy

Idle speed controlaccurate control of injection amount and timing phasing

- 1 -


2 Base for further development and estimation of potential

Combustion process

The high thermodynamic efficiency of the Diesel engine and the nature of the fuel injection process lead to high combustion pressures and temperatures. This enhances the formation of nitrous oxides and, in locally fuel rich areas, the generation of soot.

For some time now, alternative combustion processes have been under development, where fuel and air burn in a homogeneous mixture [2],[3]. These so-called HCCI processes use combinations of extremely high amounts of EGR, a large number of injections per working cycle distributed over a large range of crank angles and conside-rably higher injection pressure. The EGR is cooled strongly before being mixed with the fresh air. For the foreseeable future, these combustion processes will be suitable only for the lower and intermediate load range. Therefore, they have to be combined with conventional processes, which compel compromises in drivability during the transition. Their application is now predicted for 2012 to 2014.

The aim of future robust series applications has to be a more uniform distribution of fuel an air in the combustion chamber as hitherto. First and foremost the combustion temperature has to be controlled such that also locally the characteristic areas of NOx and soot formation are avoided. This has to be facilitated, without being caught in the narrow band of homogeneous Diesel combustion, as demonstrated in Figure 3, showing these characteristic areas as function of local gas temperature and local equivalence ratio.

Figure 3: Local areas of soot and NOx formation

From this diagram it can be concluded, that there is still potential to be derived for the optimisation of the classic combustion process. To increase EGR compatibility and the

φ – T map formed by Chemical Kinetic Models of Soot, NOx FormationToyota & ExxonMobil, SAE 2001-0-0655

NONO0

1

2

3

4

5

1400 1800 2200 2600 3000

Local Temperature K

Loca

l E

quiv

alen

ce R

atio

φ

SootSootSoot

HCCI

LTC

Conv. Diesel Combustion

φ – T map formed by Chemical Kinetic Models of Soot, NOx FormationToyota & ExxonMobil, SAE 2001-0-0655

NONO0

1

2

3

4

5

1400 1800 2200 2600 3000

Local Temperature K

Loca

l E

quiv

alen

ce R

atio

φ

SootSootSoot

HCCI

LTC

Conv. Diesel Combustion

- 2 -


efficiency of gas exchange, while using the flexibility and fuel jet penetration of the CR injection system, engine design tends towards more open combustion chambers, less swirl and lower compression ratio. Increased EGR rates, necessary for the control of the cylinder charge temperature, require higher degrees of charging in the emissions relevant areas of engine operation. For this, the range where turbo charging is effective, needs to be extended to lower engine speeds to provide a sufficiently high air mass flow at appropriate boost pressures. This can be done in several ways, e.g. VTG and waste gate as a cheap solution, VTG and VCG or two-stage charging for larger engines. Also, electrically driven super chargers can be used, promising a fast build-up of torque, but making the system expensive.

To keep charge temperature low, higher ERG rates require more intensive cooling, which in turn requires a higher cooler efficiency.

In the focus: Raw emissions

From the above considerations and results, and from earlier studies, an experimental program was conceived, with the aim of lowering the engine out emissions as far as possible, in order to minimise the use of expensive measures of exhaust gas after-treatment.

A large NOx reduction potential, also for EU6, is situated in the EUDC area, i.e. at higher part load and intermediate engine speeds. Here, the NOx raw emissions can be lowered without much effort.Results, measured for some typical operating points on the stationary-state test bed, were subsequently verified in emissions tests on a concept vehicle. The following configuration was used:

Engine: 2litre-4V-EU4-engine, combustion chamber more shallow and wider, swirl app. 75% of an EU4 application, compression ratio 16:1

Injection system: PCR2, multiple injection, 8 hole nozzle with a cd of 78% and hydraulic flow reduced by 13% with reference to the EU4 application, adjusted rail pressure

Air and EGR: improved EGR cooler, optimised EGR valve, smaller turbo charger

The investigation is demonstrated exemplary in Figure 4. The best injection patterns were found via DoE for particular operating points on the engine test bed. Then, PM-NOx trade offs were performed, three of which are shown in the left hand Figure. The dashed reference curve is that of an EU4 configuration. The blue line shows the application of lowered compression ratio and swirl, combined with multiple injections. In a third step, green line, additionally the boost pressure and EGR cooling were increased. Finally, the NOx reduction potential for stationary state operation, shown in the right hand Figure, was found.

- 3 -


Figure 4: PM-NOx-Emission in steady state NEDC

The diagrams shown in Figure 5 explain the NOx and PM results shown in Figure 4. At higher part load (diagrams on the right) a 73% reduction of NOx is achieved with 29% of EGR. Here, the mean gas temperature for the EU6 configuration is always app. 80K lower throughout the phase of diffusion combustion than that of the EU4 setup. An increase of up to 130K from 30 to 40°aTDC due to post injection, combined with small nozzle holes, allows for the reduction of PM compared to the EU4 variant.

Figure 5: Impact of injection strategies on combustion at two part load points

0 200 400 600 800 1000NOx [ppm]

HC

[ppm

]

0

20

40

CO

[ppm

]

0

500

1000

FSN

[-]

0

1

2

3

be [g

/kW

h]210

230

250

0

20

40

60

80

100

120

6 bar 8.2 bar 13.5 bar

1500 rpm 2280 rpm 2400 rpm

PM MI NOx MIPM MI+small TC NOx MI+small TCPM MI+small TC+improved EGR Cooling NOx MI+small TC+improved EGR Cooling

EU4 2 Injections = Reference 100%

EU4 BaseMod Engine + MIMod Engine + MI + improved EGR and TC

2400 rpm; 13.5 bar bmep

2 % EGR29 % EGR

0 200 400 600 800 1000NOx [ppm]

HC

[ppm

]

0

20

40

CO

[ppm

]

0

500

1000

FSN

[-]

0

1

2

3

be [g

/kW

h]210

230

250

0

20

40

60

80

100

120

6 bar 8.2 bar 13.5 bar

1500 rpm 2280 rpm 2400 rpm

PM MI NOx MIPM MI+small TC NOx MI+small TCPM MI+small TC+improved EGR Cooling NOx MI+small TC+improved EGR Cooling

EU4 2 Injections = Reference 100%

EU4 BaseMod Engine + MIMod Engine + MI + improved EGR and TC


2 % EGR29 % EGR

-10 0 10 20 30 40Crank Angle [deg]

Cyl

inde

r Pre

ssur

e [b

ar]

0

20

40

60

Gas

Tem

pera

ture

[K]

600

1000

1400

1800

Hea

t Rel

ease

[kJ/

m³d

eg]

0

50

100

150

1500 rpm; 3 bar bmep; 53 % EGR

-30 -15 0 15 30 45 60Crank Angle [deg]

Cyl

inde

r Pre

ssur

e [b

ar]

0

40

80

120

Gas

Tem

pera

ture

[K]

600

1200

1800

2400

Hea

t Rel

ease

[kJ/

m³d

eg]

0

60

120

180

2400rpm ;13,5 bar bmep; 29 % EGR

2 Injections4 injections


NOx: constPM: constCO: -27%HC: -15%SFC: +1%

NOx: -73 %PM: -19 %CO: +12 %HC: - 4 %FC: +1 %

-10 0 10 20 30 40Crank Angle [deg]

Cyl

inde

r Pre

ssur

e [b

ar]

0

20

40

60

Gas

Tem

pera

ture

[K]

600

1000

1400

1800

Hea

t Rel

ease

[kJ/

m³d

eg]

0

50

100

150

-10 0 10 20 30 40Crank Angle [deg]

Cyl

inde

r Pre

ssur

e [b

ar]

0

20

40

60

Gas

Tem

pera

ture

[K]

600

1000

1400

1800

Hea

t Rel

ease

[kJ/

m³d

eg]

0

50

100

150

1500 rpm; 3 bar bmep; 53 % EGR

-30 -15 0 15 30 45 60Crank Angle [deg]

Cyl

inde

r Pre

ssur

e [b

ar]

0

40

80

120

Gas

Tem

pera

ture

[K]

600

1200

1800

2400

Hea

t Rel

ease

[kJ/

m³d

eg]

0

60

120

180

-30 -15 0 15 30 45 60Crank Angle [deg]

Cyl

inde

r Pre

ssur

e [b

ar]

0

40

80

120

Gas

Tem

pera

ture

[K]

600

1200

1800

2400

Hea

t Rel

ease

[kJ/

m³d

eg]

0

60

120

180

2400rpm ;13,5 bar bmep; 29 % EGR



NOx: constPM: constCO: -27%HC: -15%SFC: +1%

NOx: -73 %PM: -19 %CO: +12 %HC: - 4 %FC: +1 %

- 4 -


In the lower load region, diagrams on the left, multiple injections are beneficial due to two effects: First through gas temperature control both, CO and HC can be reduced (27% and 17%, respectively, in this example) at constant NOx and PM level. This can be attributed to the increased gas temperature during the premixed combustion phase (blue curve in the diagram left-middle). The second effect is a more stable combustion at the very high EGR rate of 50% and simultaneously increased boost pressure, through a more complete use of the air available for combustion.

In this study the charge temperature was decreased by 35% in the lower and by 45% in the upper load range at fully warmed up engine.

In order to keep the injection duration at rated power constant, rail pressure must be increased by about 13% from 1600 to 1800 bar, when optimised nozzles with lower hydraulic flow and smaller nozzle hole diameters – beneficial for atomisation – are used. The maximally permissible values for exhaust gas temperature and peak cylinder pressure were maintained.

Figure 6 shows a complete NEDC test with a vehicle calibration as explained above, in the mass class up to 1590kg.For the cumulative emissions, differences in NOx become obvious from the second half of the ECE part (lower diagram). Here the effect of the EGR cooler is visible (the cooler was bypassed in the earlier part of the cycle because of low combustion chamber tempera-tures). The effect continues on a higher level in the EUDC part. In several tests NOx emis-sions of less than 90mg/km were achieved, corresponding to a 60% reduction.

Figure 6: Cumulative emission test results in the NEDC

HC

[g]

0.00.10.20.30.40.50.6

VS

[km

/h]

020406080

100120

EU6

HC: + 50 %

DOC inactive EGR cooler active

0 100 200 300 400 500 600 700 800 900 1000 1100 1200Zeit [sec]

NO

X [g

]

-0.50.00.51.01.52.02.5

PM

[mg]

050100150200250

CO

[g]

0123

Abgastest: Referenztest (Bypass EGR-Kühler geöffnet)Abgastest: Euro 4 SerienmotorAbgastest: Serienturbolader GT17

ECE: 4,05km EUDC: 6,94km

NOx: - 62 %

PM: - 17 %

CO: + 100 %

HC

[g]

0.00.10.20.30.40.50.6

VS

[km

/h]

020406080

100120

HC

[g]

0.00.10.20.30.40.50.6

VS

[km

/h]

020406080

100120

EU6

HC: + 50 %

DOC inactive EGR cooler active

0 100 200 300 4000 100 200 300 400 500 600 700500 600 700 800 900 1000800 900 1000 1100 1200Zeit [sec]

1100 1200Zeit [sec]

NO

X [g

]

-0.50.00.51.01.52.02.5

PM

[mg]

050100150200250

CO

[g]

0123

Abgastest: Referenztest (Bypass EGR-Kühler geöffnet)Abgastest: Euro 4 SerienmotorAbgastest: Serienturbolader GT17

ECE: 4,05km EUDC: 6,94km

NOx: - 62 %

PM: - 17 %

CO: + 100 %

- 5 -


The emissions of CO and HC can be reduced for engines with low compression ratio in the lower load range, using multiple injections compared to a single pilot and main. However, these engines still have elevated emissions in the test cycle compared to the initial EU4 engine configuration. This mainly is to be attributed to the aggravated conditions of catalyst light off during engine warm up in the first 100 seconds of the test, due to the low compression ratio. Up to a temperature of the cooling medium of 50° to 60°C, the EGR cooler should be bypassed. With this, a deterioration of the CO and HC emissions, compared to EU4, can be minimised. In the current study the deterioration was 100% for CO and 50% for the hydro-carbons emission. Without the cooler bypass the numbers would have been 450% for CO and 360% for HC.Another result of this integrated system approach is the reduction of the raw particulate matter by 17% with respect to the EU4 calibration. This will serve to extend regeneration intervals of the DPF.The measured fuel consumption is on the same level as that of the EU4 tuning.With these measures a good base is achieved for further optimisation, and exhaust gas after-treatment, which may become necessary, can be less elaborate.

Assessment of potential

Based on the above results, the potential for emissions reduction of vehicles with the same engine but with a higher mass can be evaluated. For this, two additional mass classes are considered.

Data on the basis of EU4 levels:Inertia: 1590 kg 1810 kg 2040 kgNOx: 0,200 g/km 0,234 g/km 0,285 g/kmPM: 0,020 g/km const. const.

As shown in Figure 7, it is just about possible to reach the EU6 NOx limit with a vehicle in the 1590kg class, however without the robust safety margin necessary for series application.Important for the rating of the overall optimisation potential are also the potentials of individual steps with reference to their base values. A reduction in NOx of 38% can be achieved alone with the optimised combustion process and the adjusted multiple injection. About 14% reduction, with respect to the initial value, is contributed by the improved charging. Another 7 % come, in this study, from the increased cooling of the recirculated exhaust gas.A vehicle with a mass of 1800kg will only come close to the low NOx limits, with a calibration including the maximum rail pressure of 2000 bar, but the limit will still be exceeded by 15%. For higher vehicle inertias in any case a NOx after-treatment will be necessary. Because this measure features a high degree of complexity, it should be considered from the start in the overall concept of the engine management.

A company-internal cost estimate showed, that the optimisation of the engine periphery alone (TC, EGR components, exhaust gas after-treatment and injection system) can lead to a cost increase of more than the double compared with the EU4 injection system.

- 6 -


Figure 7: Potential of Engine out Emission for EU6

3 Details of individual optimisation steps

Injection system

Rail pressure:

For the optimization of the NOx-PM trade off, rail pressure is increased in the relevant area of the engine map by 200 to 300 bar. To prevent degradation of the combustion noise, the pilot quantity has to be decreased in the low load range to 0,5 to 0,8 mg/cycle.

Pilot injection:

Due to its positive effect on emissions the pilot quantity will be decreased further, compared to EU 4 and 5. For example, with a decrease of only 1mg/cycle down to 0.85mg/cycle a reduction of PM in the NEDC of 20% and in NOx of 3 to 5 % is possible, without increase in combustion noise or disadvantages with respect to the other limited exhaust gas components.

Injection patterns:

The split of the total injected mass into several portions of different quantities, as explained above, is used mainly to reduce engine out emissions and to facilitate DPF regeneration. The application of a small post injection is particularly effective in the intermediate engine speed range at relatively high part loads [4],[5].

In the future, injection patterns like those shown in Figure 8 will become more common. It is to be considered, that depending on EGR rate different individual injection quantities and intervals have different effects on the emissions at different loads. For the anticipated EU6 EGR rates, very small injection quantities at relatively long injection intervals have a very positive effect [6].

0.00

0.05

0.10

0.15

0.20

0.25

0.30

0.35

1200 1400 1600 1800 2000 2200 2400

vehicle inertia (kg)

NO

x (g

/km

)

serial EU4 2 l -engine

EU5 2 l - engine wFIE PCR2.3 1800bar MI

EU5 2 l - engine wFIE PCR2.3 1800bar MI / improvedTC

EU5 2 l - engineFIE PCR2.3 1800bar MI / improvedTC / high eff. EGRcoolingEU6

based on engine dyno and vehicle

EU6 : 80 mg/km

16% Reduction necessary

32% Reductionnecessary 7%

14%

38%

- 7 -


Figure 8: Injection strategies

Injector nozzle:

The reduction of compression ratio and swirl requires an increase in energy for mixture formation via the fuel injection. This is achieved through an increase in the number of nozzle holes with a simultaneous reduction of their diameters. For an EU5 engine with 0.5 litre displaced volume per cylinder, micro-sachole nozzles with 6 to 7 holes at 110 to 120 µm diameter are standard. For EU6 micro-sachole nozzles with 8 to 10 holes at 90 to 100 µm diameter will be the norm. For an optimal usage of the in-cylinder air, higher injection pressures at rated power will be required.

Apart from the number of holes, the increase of the nozzle discharge coefficient attracts more attention. There are results, showing that a higher cd combined with optimised start of injection can reduce the engine out soot emissions to one third of that of an EU4 nozzle calibration. NOx emissions remain unchanged with appropriate adjustment. However, it has to be noted, that for cd values above 80% the tendency of nozzle coking increases drastically.With respect to compliance to the required low tolerances on injection quantity over lifetime, improvements can only be achieved via the opening and closing characteristics and the coating of the pair nozzle seat / nozzle needle (reason is the higher strain on the nozzle seat due to higher forces caused by higher needle closing speeds and a higher number of injections).

Load

1000 2000 3000 4000 5000

Peak torque

Rated power

NOISELight off

NOISENOx / PARTICULATES

TORQUECONSUMPTION

POWER

or

TORQUEPARTICULATES

Load

1000 2000 3000 4000 5000

Peak torque

Rated power

NOISELight off


TORQUECONSUMPTION

POWER

or

TORQUEPARTICULATES

Load

1000 2000 3000 4000 5000

Peak torque

Rated power

NOISELight off


TORQUECONSUMPTION

POWER

or

TORQUEPARTICULATES

Load

1000 2000 3000 4000 5000

Peak torque

Rated power

NOISELight off


TORQUECONSUMPTION

POWER

or

TORQUEPARTICULATES

- 8 -


Fuels

The EU demands from 2010 a bio share of 5,75% of the energy used for transport. Regarding experiences at Siemens VDO fractions of up to 5% RME of the diesel fuel (B5) according to EN14214 are not of concern for the injection system. Also blends with 10% RME did not cause problems in test runs. Higher fractions can be handled concerning combustion, but fuel quality and phenomena of ageing e.g. formation of polymers (formation of gums within the injection system, sticking of moving parts) and corrosion, caused by acidification, can cause system failure.

These for a considerable market introduction in 2010 discussed synthetic fuels (like BTL, GTL und CTL), do have shorter induction times, caused by lower fractions of PAH and higher Cetane numbers and, hence, may be less suitable for alternative combustion processes. These work better with long induction times to facilitate homogenisation. The potential for emissions reduction of these fuels lies primarily with CO, HC and PM. There is virtually no effect on NOx [7].

In order to comply with the low emission limits of EU6 the calibration of injection start might need to be adapted to fuel composition via a combustion pressure sensor [7].

The future will be a mixture of fossile, methyl-estered (RME, FAME) and synthetic fuels. Neither methyl-estered nor synthetic fuels alone will be available on the market in sufficient quantity in the near future. Currently great efforts are undertaken, to increase the production capacity of the latter. Consequently, the mixture fraction in future fuels is largely undetermined. At least the norm EN 590 should be adhered to, by novel fuels and the resulting blends. Therefore the fraction of synthetic fuel in standard diesel should be less than 30%. However, even in 2015 only 4% of the world Diesel fuel production will be synthetics [8].

Air-EGR path

The application of low temperature EGR, discussed ever again, with recirculation to the front end of the turbo charger, will not have a break-through in passenger cars, if only due to cost and space restrictions. Also the disposal of dirt and corrosion in the compressor is significant. Additionally the usual car operation requires fast transient response with fast controls and short supply lines, which would lead to a twofold EGR system. The consequence is, that rather than using low temperature EGR, "hot" EGR must be distributed more uniformly to all cylinders than hitherto necessary, still complying to the demand of fast transient rate response. Simultaneously the deviation on factors, which influence combustion stability, have to be narrowed down.

Tolerance analysis of the dosing of oxygen

In the past much attention has been given to the systematic improvement of the injection system. In future there will be equally high importance attached to the second partner in combustion, the oxygen content in the cylinder charge. With a study of the unequal distribution of the charge to individual cylinders, the respective tolerances and the required software strategies, it is possible to systematically determine how to combine sensors, actuators and software strategies to a cost effective system solution.

- 9 -


Figure 9: Charge-O2 tolerance analysis in the emission relevant area

Control of the EGR rate constitutes a key element in terms of the allocation of air and fuel to each individual cylinder or engine, respectively. The knowledge of the exactness of the O2 content, available for the combustion, becomes more important the higher the amount of EGR is. This applies also to the impact of the tolerances of relevant components on the O2 concentration. Basis for the analysis are the operating points and results of the NOx reduction study described earlier in this paper.Figure 9 shows, in the upper right diagram, for both operating points (1500rpm, 3bar and 2400rpm, 13,5bar) the influence of non-uniform oxygen content on the relative NOx deviation. If a cylinder-to-cylinder or engine-to-engine deviation of 0.2% in the O2concentration is assumed, this can lead to a spread of NOx emissions of 10 to 15%, with higher deviations at low load and high EGR rates and vice versa.The left half of Figure 9 presents individual measures in both operating points (upper and lower diagram). If all the above considerations are transferred to the entire emissions test area, then this results in the assessment shown in the lower right diagram. This is a comparison of error trends as well as the effects of individual sensor accuracies on the O2concentration, and suggestions are made as to which measures should be taken to narrow down the tolerance of the O2 concentration in the cylinder charge.

In both operating points the absolute error on the determination of O2 concentration can be reduced by about 16%, if the air mass measurement with the improved EU5 air mass sensor is corrected additionally by a wide range Lambda sensor in the exhaust system. This means, that in the emissions test range the Lambda control provides an improvement of about 28% against EU4 and therefore is the benchmark against which all optimisations

Lambda,

-6%

-27%-28%

-42%

-46%

0%

-50%

-40%

-30%

-20%

-10%

0%

EU 4SIMAF GT3,full eng. disp

SIMAF GT3,adapt eng. disp

no MAFdisp, all eng. disp

UMAF, adapteng. disp

Dual MAF, noeng. disp

O2

Erro

r com

pare

d to

EU

4 re

fere

nce

0.00%

0.25%

0.50%

0.75%

1.00%

1.25%

Tend

ency

of E

rror

Proportional improvement of O2error compared to EU 4 referenceTendency of error on intake O2

0.0%

0.5%

1.0%

1.5%

2.0%

12% 15% 18% 21%

O2, intake

abs.

Err

or o

n [O

2]in

take

0.00

1.00

2.00

3.00

4.00

Lam

bda-

Exha

ust /

EG

R-R

ate

[%/1

00]

EU5-SIMAF GT3 & eng. disp

EU5-SIMAF GT3 & adapt eng. disp

UMAF & adapt eng. disp

Dual MAF & no engine disp

Lambda, no MAF disp & eng. disp

Lambda-Exhaust

EGR-Rate

EU 6


0.0%

0.5%

1.0%

1.5%

2.0%

12% 15% 18% 21%

O2, intake

abs.

Err

or o

n O

2, in

take

0.0

1.0

2.0

3.0

4.0

Lam

bda-

Exha

ust /

EG

R-R

ate

[%/1

00]




Dual MAF & no eng. disp


Lambda-Exhaust

EGR-Rate

EU 6

1500 rpm; 3 bar bmep

0%

50%

100%

150%

200%

250%

12% 13% 14% 15% 16% 17% 18% 19%O2

NO

xre

l.

1500 rpm; 3 bar bmep2400 rpm; 13.5 bar bmep

Source: FEV

± 0,2 % O2

+11%-12 %

+15%-14 %

Lambda,

-6%

-27%-28%

-42%

-46%

0%

-50%

-40%

-30%

-20%

-10%

0%






O2

Erro

r com

pare

d to

EU

4 re

fere

nce

0.00%

0.25%

0.50%

0.75%

1.00%

1.25%

Tend

ency

of E

rror


Lambda,

-6%

-27%-28%

-42%

-46%

0%

-50%

-40%

-30%

-20%

-10%

0%






O2

Erro

r com

pare

d to

EU

4 re

fere

nce

0.00%

0.25%

0.50%

0.75%

1.00%

1.25%

Tend

ency

of E

rror


-6%

-27%-28%

-42%

-46%

0%

-50%

-40%

-30%

-20%

-10%

0%






O2

Erro

r com

pare

d to

EU

4 re

fere

nce

0.00%

0.25%

0.50%

0.75%

1.00%

1.25%

Tend

ency

of E

rror


0.0%

0.5%

1.0%

1.5%

2.0%

12% 15% 18% 21%

O2, intake

abs.

Err

or o

n [O

2]in

take

0.00

1.00

2.00

3.00

4.00

Lam

bda-

Exha

ust /

EG

R-R

ate

[%/1

00]




Dual MAF & no engine disp


Lambda-Exhaust

EGR-Rate

EU 6


0.0%

0.5%

1.0%

1.5%

2.0%

12% 15% 18% 21%

O2, intake

abs.

Err

or o

n O

2, in

take

0.0

1.0

2.0

3.0

4.0

Lam

bda-

Exha

ust /

EG

R-R

ate

[%/1

00]




Dual MAF & no eng. disp


Lambda-Exhaust

EGR-Rate

EU 6

1500 rpm; 3 bar bmep

0%

50%

100%

150%

200%

250%

12% 13% 14% 15% 16% 17% 18% 19%O2

NO

xre

l.


Source: FEV

± 0,2 % O2

+11%-12 %

+15%-14 %

0%

50%

100%

150%

200%

250%

12% 13% 14% 15% 16% 17% 18% 19%O2

NO

xre

l.


Source: FEV

± 0,2 % O2

+11%-12 %

+15%-14 %

- 10 -


have to be measured (see lower right diagram). While the EU5 optimised air mass sensor, MAF, alone achieves only a 6% improvement, it is possible to achieve similarly good results then with the Lambda control also with a new adaptation function without the use of additional sensors, e.g. the Lambda sensor. So, a necessary, considerably more intensive engagement with the different adaptation possibilities is required. Further improvements, at EGR rates of 29% for the higher load EUDC point and 53% for the lower ECE point, canbe achieved with the application of an Ultrasonic MAF with adaptation function or with the combined application of MAF and EGR mass flow sensor. This roughly halves the O2 error compared to a single MAF, and the Lambda sensor can be omitted to reduce cost. Before introducing the MAF/EGR-MAF combination, a rigorous overall cost analysis has to be performed because of the possibly higher cost incurred. Hence, the key to further improvements lies rather with a robust MAF sensor plus adaptation function, which should include two things: the MAF adaptation itself and an adaptation of the volumetric cylinder-to-cylinder deviation. With these measures an improvement of app. 40% against EU4 can be achieved. To enhance transient behaviour, optimised pre-controls, which describe the physical process of filling the engine with air and EGR, e.g. the model based air path (see Section 5), are helpful.

This brief comparison shows once again, that in the future it is all the more important to simultaneously optimise not only the components but also their accompanying functions.

4 Exhaust gas after-treatment

Concerning exhaust gas after-treatment, three measures have to be distinguished, two of which will be mandatory already for EU5, the long introduced oxidation catalyst for CO and HC and the DPF for the reduction of particulate emissions. For the NOx reduction there are, depending on the application, also two options under development: SCR and LNT.

CO and HC oxidation

Engine concepts with low compression ratio may have lower exhaust gas temperatures before DOC as a standard EU4 configuration. At the same time the light off temperature of the catalyst is increased due to the higher CO concentration (and subsequently lower HC) in the exhaust gas. This is to be considered in the design of the DOC by use of different coatings, e.g. Pd/Pt [9]. To simply increase the concentration of an oxidation catalyst does not seem to be practical. It will cause not only higher costs, but also increase the level of NO2 formation. Regarding the implementation of an EU-wide NO2 immissions directive at the same time with EU6, the situation will tighten on vehicles without active NOx conversion.

Particle reduction

Both types of filters currently on the market, the fuel additive assisted and the catalytically coated, will also compete for EU6.The additive-assisted filter, which has been on the market longer than the catalytic one, can now reach lifetimes of up to 240000km [10].Catalytically coated filters in turn pose higher demands on the control functions for filter loading and regeneration, because their coating makes them thermally less robust.

- 11 -


Higher regeneration temperatures for the coated filter of 600° to 650°C require a higher energetic effort and, hence, cause higher fuel consumption.

In CylinderPressure Sensor

MAF

ExhaustTemperature

Sensor

Pump

NOX Sensor

Pressure, temp.sensor

Urea Tank(heated)

Tank LevelSensor

Optional

Oxi-cat

Guard-cat

Lines (heated)

Filter

Dosing Control

On BoardDiagnostics

Engi

ne C

ontr

ol U

nit

SCRCat DPF

EFIExhaustTemperature

Sensor

NH3- Quantity

NOxConcentration

Cat. Efficiency

∆p-Sensor

In CylinderPressure Sensor

MAF

ExhaustTemperature

Sensor

PumpPump

NOX Sensor

Pressure, temp.sensor

Urea Tank(heated)

Tank LevelSensor

Optional

Oxi-cat

Guard-cat

Lines (heated)

Filter

Dosing Control

On BoardDiagnostics

Engi

ne C

ontr

ol U

nit

SCRCat DPF

EFIExhaustTemperature

Sensor

NH3- Quantity

NOxConcentration

Cat. Efficiency

∆p-Sensor

Figure 10: Example of exhaust gas after-treatment measures, Siemens VDO demonstrator

The necessary engine measures to increase the exhaust gas temperature primarily comprise the application of a post injection. Here the great advantages of the highlyflexible Common rail injection technology become obvious.

Another possibility is the fuel injection into the exhaust gas system before the DPF. This achieves two things: oil thinning and washing off of the oil film from the cylinder wall, caused by very late post injections for filter regeneration, is avoided. Also the injection of only the minimally required amount of fuel improves the fuel consumption.A very simple system is the EFI (Exhaust Fuel Injector) of Siemens VDO, which can be run from the internal transfer pump of the CR high pressure pump as well as from an electrical pump directly from the fuel tank. It consists of a from the exhaust system thermal decoupled gasoline port fuel injector of the latest generation for dosing the fuel and a spring-loaded poppet valve for the uniform distribution of the fuel at an appropriate location in the exhaust line before the DPF

Because the expectations into life expectancy increase, it will be necessary to improve the accuracy of the regeneration management. This is to avoid thermal overloading of the catalyst and catalytically coated filter and to avoid cracking of the substrate due to local thermal stress over the entire lifetime. This is particularly important if, for cost reasons, less temperature resistant materials like Cordierite are used [9].

NOx conversion (DeNOx)

Due to its cost, after-treatment of nitrous oxides should always be seen in addition to the engine internal NOx reduction measures described above. For EU6 SCR as well as NOx storage technologies are to be considered.

- 12 -


The introduction of SCR in the commercial vehicle sector for compliance to the Euro4 limits affirms the potential of this technology. In the passenger car sector there are two big challenges: the solution favoured for commercial vehicles, the air assisted urea injection, cannot be used for passenger cars. Therefore a method for the proportional admixing of the reducing agent AUS32 into the exhaust stream and the uniform distribution across the catalyst entry face has to be found. If AUS32 locally reaches excessive concentrations, ammonia slip is the consequence. The second challenge is the lack of freezing resistance of the watery urea solution, which already ices up at •11°C. For this, corresponding counter measures have to be provided for the urea tank, supply lines and valves. The alternative to SCR is the NOx storage technology, also known as NOx trap. For this, the calibration of the Diesel combustion process in the rich region is relatively stable in the intermediate load range. However, the challenge is the catalyst regeneration, because at short regeneration intervals there is a danger of only regenerating the surface of the NOx storage medium. This would continuously reduce the available storage capacity. However, If regeneration lasts too long, slip of the reducing agent will result. Because CO is the only reducing agent, a high ratio of CO over HC should be supplied to the catalyst.

Outside the typical NEDC operating region, the injection duration - expressed in degrees crank angle – can be extended with engine speed, until it is limited by wall wetting, i.e. engine oil thinning and soot formation. However, higher in-cylinder temperatures cause a stronger exothermic conversion of the post injection already in the region of the outlet valve, increasing the thermal and mechanical load on the turbo charger. Additionally, a fraction of the stored NOx is released when switching from normal to rich operation at higher loads. This is due to temperature peaks at the catalyst in the transition to under-stoichiometric operation.

In the case of sulfur poisoning, there is no possibility to bypass unsuitable regeneration conditions by stoichiometric engine operation, to avoid further NOx emissions. Because a desulfation is not possible under all operating conditions, low sulfur fuels are mandatory.

Combination of DPF and DeNOx

To reduce cost, DPF and Lean NOx Trap, LNT, can be combined for vehicles with relatively low NOx reduction requirements. Generally there are two constellations possible, each with its own advantages and disadvantages. The placement of the NOx trap before the additive assisted DPF allows for an installation of the catalyst closer to the engine, which yields higher temperature levels and, hence, better conversion efficiencies. Damage of the trap due to exothermal conditions, when the DPF is regenerated, is impossible. Soot loading of the DPF does not influence the trap regeneration. The succession of components corresponds to the gradient of necessary regeneration temperatures. For an additive assisted DPF these are relatively low at 450°C, whereas the NOx trap requires a desulfation temperature of 650°C.If a catalytically coated DPF is used, the order should be reversed to use the CRT effect. However, an adequate minimum temperature level of the NOx trap has to be achieved, to safeguard a sufficiently high storage capacity during inner city driving and particularly light off. The biggest problem will be the relatively high thermal inertia of conventional particulate filters.The control strategies for the NOx trap includes functional synergies with the direct injection gasoline engine, but are adapted to specific Diesel combustion characteristics.

- 13 -


These synergies can be used in common modules, like e.g. the elevation of the exhaust gas temperature together with the DPF control.

5 Structure of strategies in the engine management

The engine management has to take over ever more tasks in finding the best optimisation compromise. One example is the air path, already mentioned above, with its long reaction time. For its optimization, model based strategies, as shown in Figure 11, will be applied increasingly [11]. The measurement of the air mass in EGR systems mass will be improved. Simultaneously the accuracy of signal processing in the engine ECU will be improved. To get a feedback signal to be used for a closed loop control, EGR valves with electric actuators will be used. Only this will allow for the application of ever more complex functions, particularly for transient operation.

Because the required oxygen for combustion will be supplied, as described above, by different turbo charger configurations, different modules for turbo charging functions will be interchangeable, as shown in Figure 11.

The advantage of this model based, non-linear control structure is the simpler compensation of disturbances. Also it is easily adaptable to different operating conditions, e.g. transient turbo charger and EGR valve characteristics and switchable combustion modi.

G11

G12

G21

G22measair,m&

spair,m&

sp2i,p meas2i,pControl pathModel Based Controller

boostcontrol

EGRcontrol

Inverseturbine-model

InverseEGR-valve

model

EGR-decoupling

boost decoupling

VTGs

EGRsdec3,p

CTL3,p

CTLEGR,m&

decT,m&Enginemodel

coordinationof

HP turbine&

LP turbine

coordinationof

VTG&

Wastegate

exchangeable TC Function Modules

G11

G12

G21

G22measair,m&

spair,m&

sp2i,p meas2i,pControl pathModel Based Controller

boostcontrol

EGRcontrol

Inverseturbine-model

InverseEGR-valve

model

EGR-decoupling

boost decoupling

VTGs

EGRsdec3,p

CTL3,p

CTLEGR,m&

decT,m&Enginemodel

coordinationof

HP turbine&

LP turbine

coordinationof

VTG&

Wastegate

exchangeable TC Function Modules

Figure 11: Simplified model based airpath

Another example for an integrated engine-emissions management is the injection control when the engine is cold. The emissions reduction during warm-up via multiple injection is to be coordinated with the temperature management for exhaust gas after-treatment and cylinder charge temperature. To improve catalyst light-off at low engine temperatures, the injection control will use a different timing and different quantities as for warm engine. At

- 14 -


the same time, as described above, CO, HC and combustion noise can be influenced positively by multiple injections.

If HCCI combustion processes are applied for part load together with exhaust gas after-treatment, injector triggering will be required over app. 360° crank for each cycle. Six to seven injections will probably be necessary, with intervals between injections varying between very wide and hydraulically zero. To master this, a combustion control via characteristic quantities derived from the cylinder pressure signal will become necessary. For this, Siemens VDO is developing a cylinder pressure sensor, the Glow Plug Pressure Sensor GPPS, with for sensor signal evaluation and combustion control required func-tionality [12].

The necessary flexibility for these partly contradicting requirements – emissions, combustion noise, fuel consumption – results in a vast variation of injection modi, the coordination of which will be taken over by the "combustion manager".

The combustion manager, Figure 12, controls injection quantity according to driver demand. Also considered are parameters which will influence the injection, like the necessity of the regeneration of the DPF (either by post injection or by triggering the EFI), elevation of the exhaust gas temperature during warm-up to improve light off, a start-stop function etc. Together with each injection strategy, also the pre-control values for rail pressure, EGR and boost pressure control will be defined.With this structure, tools like DOE can be applied more focused and the calibration effort will be reduced.

Figure 12: Combustion Manager

InjectionPhasingSetpoint

Fuel MassSetpoint

Fuel Pressure

Air Mass Setpoint

EGRSetpoint

MF_SP

SOI_SP

FUP_SP

MAF_SP

EGR_SP

Multiple Injection Strategy

DPFSupervisor

DPFManager

Split InjectionManager

Other ManagersMFMA, LIH,HCCCI,.......

Start-StopManager

-

Injection Realisation

Fuel Pressure

Realisation

Air PathRealisation

Fast Light OffCatalystManager

Normal InjectionManager

Boost PressureSetpoint

MAP_SP

NOxAftertreatment

Manager

BSW

CombustionManager

InjectionPhasingSetpoint

Fuel MassSetpoint

Fuel Pressure

Air Mass Setpoint

EGRSetpoint

MF_SP

SOI_SPSOI_SP

FUP_SP

MAF_SP

EGR_SP

Multiple Injection Strategy

DPFSupervisor

DPFManager

Split InjectionManager

Other ManagersMFMA, LIH,HCCCI,.......

Start-StopManager

-

Injection Realisation

Fuel Pressure

Realisation

Air PathRealisation

Fast Light OffCatalystManager

Normal InjectionManager

Boost PressureSetpoint

MAP_SP

NOxAftertreatment

Manager

BSW

CombustionManager

- 15 -


Stability of small injection quantities:

Very small injection quantities, particularly required for multiple injection strategies, have to be stable for a now much prolonged lifecycle. This can only be assured without drift, using the ECU function MFMA (= Minimal Fuel Mass Adaptation), which keeps the tolerance to app. ±0.3 mg/cycle over the demanded system lifetime as well as injector-to-injector.The required reduction of the tolerance bandwidth is supported additionally by the function IIC (= Injector Individual Control), which corrects - without additional cost - the injector-individual quantity deviation. This is measured during the final injector testing in production compared to a "norm-injector".

Because the control accuracy of the rail pressure also affects the control accuracy of the injector triggering, this will also be improved (Figure 13). This is particularly important for transient operation and with regard to the shot-to-shot stability.

Also the drift of blind lift over lifetime is kept in narrow tolerances by an adaptation function.

Figure 13: Influencing factors on minimum injection quantity and NOx- and PM Emission

Figure 13 also emphasises, using the example of constant tolerance of the minimum fuel quantity over lifetime, that only the concerted optimisation of components (red

Injectoropening / closing characteristics

Minimal fuel mass adaptationenergy control

Piezodriver functionality

Fuel pressure control Blind lift adaptation

Minimal fuel mass adaptation

Stability shot to shot Stability inj to inj minimal quantity no drift

Minimal Injection Quantity

0.10

0.15

0.20

0.25

0.01 0.02 0.03 0.04 0.05 0.06

PM g/km

Nox g/kmwithout MFMA

with MFMA

Emissions impact:

Particulates : - 42 % on dispersion- 17 % on absolute value

Nox:- 15% on dispersion

with MFMAwithout MFMA

System Robustnessnozzle seat coating

Functionality

Component

Injectoropening / closing characteristics

Minimal fuel mass adaptationenergy control

Piezodriver functionality

Fuel pressure controlenergy controlPiezodriver functionality

Fuel pressure control Blind lift adaptation

Minimal fuel mass adaptation

Stability shot to shot Stability inj to inj minimal quantity no drift

Minimal Injection Quantity

0.10

0.15

0.20

0.25

0.01 0.02 0.03 0.04 0.05 0.06

PM g/km

Nox g/kmwithout MFMA

with MFMA

Emissions impact:

Particulates : - 42 % on dispersion- 17 % on absolute value

Nox:- 15% on dispersion

with MFMAwithout MFMA

System Robustnessnozzle seat coating

Functionality

Component

Functionality

Component

- 16 -


background) and functions (yellow background) will assure, not only to achieve the emissions limits but also to maintain this more accurately over lifetime.

6 Summary

In order to master the future challenges of emissions legislation, it is necessary to reinforce the further integration of measures concerning engine combustion, the injection system, the air path and the exhaust gas after-treatment under the roof of the engine management system. The intelligent combination of its control functions will allow for an enhancement of the performance of modern Diesel vehicles, without neglecting cost.

For a vehicle in the 1600kg class it has already been proved that it is generally possible to reduce the NOx emissions very far. However, for series application there still remains extensive testing with respect to overall system robustness and lifetime stability.

Vehicles with higher inertia have less NOx reduction potential. For those vehicles, it will be difficult to avoid NOx after-treatment.

Depending on customer requirements, cost effective measures can be combined for series application.

Characters used in formulae und indices

DPF diesel particulate filterDOC diesel oxidation catalystECE economic comission of EuropeEUDC extra urban driving cycleEFI exhaust fuel injectorEGR exhaust gas recirculationFIE fuel injection equipmentHCCI hogeneous charge comprseeion ignitionMFMA minimal fuel mass AdaptationMAF mass air flowMI multi injectionLNT lean NOx trapLTC low temperature combustion NEDC new vehicle emission cyclePCR piezo common railTC turbo chargerVCG variable compressor geometryVTG variable turbine geometry

- 17 -


Literature:

[1] Autohersteller erreichen derzeit ihre selbst gesetzten Klimaschutz-Ziele nicht,F. Dudenhöffer, Capital, 15.01.2007

[2] Neue Technologien zur Erfüllung der Abgasnorm Euro5,B. Gatellier, B. Gessier, J. Genoist, A. RaniniMTZ 2005, 06

[3] Alternative Brennverfahren – ein Ansatz für den zukünftigen Pkw-Dieselmotor,Weissbäck, M.; Csato, J.; Glensvig, M.; Sams, T.; Herzog, P. L.;MTZ 2003, 09

[4] EU5 und danach: Integriertes Management von Verbrennung und Abgas bei PKW-Common-Rail Dieselmotoren,L. Carton, O. Graupner, W. Klügl, K. Wenzlawski,13. Aachener Motorensymposium, 2004

[5] Combination of High EGR Rates and Multiple Injection Strategies to Reduce Pollutant Emissions,N. Dronniou, M. Lejeune, I. Balloul, P. Higelin,SAE-Paper 2005-01-3726, 2005

[6] Multiple Injection Strategies and their Effect on Pollutant Emission in Passenger Car Diesel Engines,O. Kastner, F. Atzler, A. Müller, A. Weigand, K. Wenzlawski, H. ZellbeckThiesel 2006, Valencia, September 2006

[7] Motorisches Potential von synthetischen Dieselkraftstoffen,N. Steinbach, H. Harndorf, F. Weberbauer, Dipl.-Ing. M. Thiel,MTZ 2006, 02

[8] The Potential of GTL Diesel to Meet Future Exhaust Emission Limits,P. Schaberg,12. Diesel Engine Emission Reduction Confererence, Detroit, August 2006

[9] Abgasreinigung beim Dieselmotor- Eine Herausforderung mit Blick auf die zukünftige Emissionsgesetzgebung,P.C, Spurk, F.-W. Schütze, S. Frantz, M. Kögel, G. Jeske,4. AVL-Partikelforum, 2006

[10] Additive Concepts of the third generation: new opportunities for vehicle applicationL. Rocher, F. Garcia,CTI 2. Exhaust systems and pollution control, Paris, June 2006

[11] Modellbasierte simultane Auflade- und AGR-Regelung für Pkw-Dieselmotoren, A. Schwarte, Chr. Birkner, M. Nienhoff, A. Kornienko, I. Koops, M. Gilch,Aufladetechnische Konferenz, Dresden, September 2005

[12] Glühkerzenintegrierter Piezokeramischer Brennraumdrucksensor für DieselmotorenJ. Burrows, S. Goretti, A. Ramond, G. Troy, MTZ 2005, 11

Documents

Diesel Engine for Passenger Car and EU6: Entirely ... - Green …bioage.typepad.com/greencarcongress/docs/Tech_Paper_Vienna_20… · 27-04-2007 · The future of the Diesel engine