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Prepared by Mike MayTechnical Specialist, Performance and Emissions

Chicago Technical Center, Ricardo Inc.

Development and Demonstration of Fischer-TropschFueled Heavy-Duty Vehicles with Control Technologies for Reduced Diesel Exhaust

Emissions

9th Diesel Engine Emissions Reduction ConferenceNewport, Rhode Island, 24-28 August 2003

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Program Contributors

South Coast Air Quality Management District RFP #P2002-18National Renewable Energy LaboratoryDepartment of EnergyCalifornia Energy CommissionOther participants:– Cummins Engine Company – Supplied engines, modified

hardware and engineering support– Cleaire – Supplied aftertreatment system and controllers– Shell – Supplied Fischer Tropsch and low aromatics baseline

test fuel– Automotive Testing Laboratories – Supplied program

management and will be responsible for vehicle installations– Ralph’s Grocery - Will use the 2 vehicles for 6 month in service

operation

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Overall Program ObjectivesDevelop the engine including the use of an aftertreatment system to take advantage of the fuel properties of Fischer Tropsch (F-T) fuel for emissions reduction with minimal reduction in engine efficiency.Demonstrate the improved emissions on vehicles fitted with modified engine and aftertreatment systems operated in the field for 6 months.

F-T Fuel Properties

276Cetane -0.83200.7836Density g/cm38.1

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Objectives of Engine Development Task

Perform transient dynamometer tests to establish baseline hydrocarbon (HC), NOx, CO, PM, and CO2 emissions from each unmodified engine when fueled alternately by F-T and base diesel fuels. Modify the engines’ combustion systems to take advantage of the high cetane value of F-T fuel and improve the EGR tolerance.Retrofit the engines’ exhaust systems with a NOx catalyst and diesel particle filters to meet the emissions goals of:

NOx 1.2 g/hp.h PM 0.01 g/hp.hHC 1.3 g/hp.hCO 15.5 g/hp.hNO2 0.4 g/hp.h

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Overview of ApproachNOx

Baseline 2002 Cummins ISM with EGR, 2.3 g/hp.hbase diesel:

Using F-T diesel fuel 2.0 g/hp.h

Higher EGR rate, new combustion bowl, 1.5 g/hp.hF-T diesel:

Higher EGR rate, new combustion bowl, 1.2 g/hp.h F-T diesel, DPF, Lean NOx catalyst:

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Cummins ISM EngineCummins supplied two ISM 6 cylinder 10.8 liter heavy duty dieselengines, certified to October 2002 emissions limits, features include:– High pressure electronically controlled unit injector– 4 valves/cylinder– Two piece pistons with steel crown– Cooled EGR– Variable geometry turbocharger

Cummins supplied 2 sets of specialECM’s which allowed new calibrationsto be programmed, plus softwareand training

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Engine in Testcell at Ricardo

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Summary of Baseline ResultsComposite (weighted cold and hot) FTP results on the low aromatic base fuel and F-T fuels are as follows:

At the same engine fuelling peak power is slightly reduced on F-T fuel due to the lower fuel density.

Fuel NOx THC PM BSFC Engine Buildg/hp.h g/hp.h g/hp.h g/hp.h

Base 2.08 0.33 0.125 196.5 BaseF-T 1.96 0.22 0.102 191.8 Base

% Reduction 5.5 33.4 18.7 2.4

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Modified Combustion BowlCombustion bowl was modified to reduce compression ratio to improve air utilization and generate more air motion to compensate for higher EGR

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EGR Response

Example of the engine response to varying EGR rate at a part load operating point, for various engine builds

0.0

0.5

1.0

1.5

2.0

1.0 1.2 1.4 1.6 1.8 2.0

NOx [g/hp.h]

Smok

e [F

SN]

220

225

230

235

240

245

250

1.0 1.2 1.4 1.6 1.8 2.0

NOx [g/hp.h]Fue

l Con

sum

ptio

n [g

/kw

.h]

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Modified EGR Map

EGR rate is substantially increased, chart shows ratio of new EGR rate to baseline EGR rate

5

25 75

125

175

225

250

325

900

1300

17002100

0.0

10.0

20.0

30.0

40.0

50.0

60.0

EGR Fraction Change [%]

Fuel [mg/st]

Speed [rpm]

EGR Fraction % Increase

0.0-10.0 10.0-20.0 20.0-30.0 30.0-40.0 40.0-50.0 50.0-60.0

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FTP Results With Modified Combustion

Composite FTP results below show the effect of the combustion system changes and increased EGR

Fuel NOx THC PM BSFC Engine Buildg/hp.h g/hp.h g/hp.h g/hp.h

F-T 1.96 0.22 0.102 191.8 BaseF-T 1.56 0.18 0.122 197.0 Modified combustion, increased EGR

% Reduction 20.5 17.3 -20.1 -2.7

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Aftertreatment System

DPF

DPF

LNC

LNCSe

cond

ary

Fuel

Inje

ctor

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Catalyst DeNOx Response

Secondary fuel rate of 12 HC:NOx ratio selected

Lean NOx Catalyst Temperature Response

-10-505

1015202530354045

150 200 250 300 350 400 450

Temperature [degC]

NO

x C

onve

rsio

n [%

] HC:NOx 2HC:NOx 4HC:NOx 6HC:NOx 8HC:NOx 10HC:NOx 12HC:NOx 16

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Final Optimized Engine Results

Overall emission reduction compared to base engine on base fuel:

Composite results (cold and hot FTP cycles) compared below.Effect of the catalyst and DPF on emissions:

Fuel NOx THC PM BSFC Engine Buildg/hp.h g/hp.h g/hp.h g/hp.h

F-T 1.52 0.19 0.122 196.8 Modified combustion, increased EGRF-T 1.17 0.04 0.005 205.2 As above with exhaust aftertreatment

% Reduction 23.1 77.2 96.0 -4.3

Fuel NOx THC PM BSFC Engine Buildg/hp.h g/hp.h g/hp.h g/hp.h

Base 2.08 0.33 0.125 196.5 BaseF-T 1.17 0.04 0.005 205.2 Mod. Comb, incr. EGR, Aftertreatment

% Reduction 43.9 87.3 96.1 -4.4

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Final Optimized Hot FTP Cycle NOx Trace

0

10

20

30

40

50

60

70

0 2000 4000 6000 8000 10000 12000

Time [s x10]

Dilu

te N

Ox

[ppm

]

BaseBuild_BaseFuel BaseBuild_FTFinalBuild_w/oAft_FT FinalBuild_withAft_FT

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Final Optimized Hot FTP Cycle HC Trace

0

5

10

15

20

25

30

0 2000 4000 6000 8000 10000 12000

Time [s x10]

Dilu

te T

HC

[ppm

]

BaseBuild_BaseFuel BaseBuild_FTFinalBuild_w/oAft_FT FinalBuild_withAft_FT

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ConclusionsSignificant improvements in base engine emissions were measured with F-T fuelThe engines have been modified to take advantage of superior properties of the F-T fuel and an aftertreatment system was installedEmissions targets are achieved, the testcell work is complete and the two engines are ready for installation in the vehicles:

The fuel consumption penalty over the FTP cycle was 4.4% for a 43.9% reduction in NOx emissions. The increased EGR + lean NOx catalyst + DPF approach shows potential for meeting 2007 emissions standards.

FTP Cycle Target Achievedg/hp.h g/hp.h

NOx 1.2 1.17Pm 0.01 0.005HC 1.3 0.04CO 15.5 0.06NO2 0.4 0.3

Development and Demonstration of Fischer-Tropsch Fueled Heavy-Duty Vehicles with Control Technologies for Reduced Diesel Exhaust EmissionsProgram ContributorsOverall Program ObjectivesObjectives of Engine Development TaskOverview of ApproachCummins ISM EngineEngine in Testcell at RicardoSummary of Baseline ResultsModified Combustion BowlEGR ResponseModified EGR MapFTP Results With Modified CombustionAftertreatment SystemCatalyst DeNOx ResponseFinal Optimized Engine ResultsFinal Optimized Hot FTP Cycle NOx TraceFinal Optimized Hot FTP Cycle HC TraceConclusions