1

Diesel Engine Alternatives

Thomas W. Ryan III August 2003

2

BackgroundEngine Combustion ModesThree Fundamental Modes of Combustion in Reciprocating Engines

Diffusion CombustionConventional DieselStratified Direct Injection SI

Flame Propagation CombustionConventional Gasoline SILean Burn SI

Homogeneous ReactionHCCI

3

Basic Question

How will future emissions regulations affect the selection of the most cost effective engine and powertrain system for the various on-road and off-road applications?

4

US On-Road Emissions Standards

Light Duty Standards through Tier I Differentiated Between Gasoline and Diesel Fuel

Tier II Light Duty Standards are Fuel NeutralUS Heavy Duty Market is Historically Diesel

Heavy Duty Standards have Historically Aimed at Diesel EnginesWill Future HD Standards be Fuel Neutral?

5

Situation

Emissions Standards for All Categories of Engines and all Applications have continually become more Stringent, Approaching Zero Emissions

In Fact, California Defined ZEV’s and PZEV’sAs Each category comes into Compliance, the other Categories Tend to become Larger Contributors to the Ambient Air Inventory

Becoming Targets for Additional Regulation

6

Definition of Ambient Air Qualityfrom the EPA Website

7

Definition of “Criteria” Pollutants

8

Effect of Regulations on Ambient Air Quality

9

Summary

EPA is Focused on Ambient Air Quality and Achieving the Ambient Air Quality Standards

This will not Change unless there is a New Law Approved by the US Congress and the Current AdministrationCO2 Standards are not Likely to be Approved in this AdministrationSome CAFÉ Changes (Minor) are Likely, Possibly including LDT’s in the same Category as LDV’s

Current Trends and Air Quality Model results indicate that the Ambient Air Quality Standards will still not be Achieved, even with the Current Regulations that are in Place

10

Background Statement

EPA will continue to promulgate lower emissions standards for diesel engines.The EPA always considers the best available technology for lowest emissions, with some consideration of the economic and social impactSI and CI Treated the same in TIER II

Fuel NeutralSI engines with 3-way catalyst are the proven lowest emission commercial technology available

11

Possible Future Action

2010 EPA can Announce New HD Standards for Implementation in 2014Future HD Standards are Likely to be Fuel NeutralPossible 2014 Standards

0.05 gm/hp-hr NOx0.001 gm/hp-hr PM

12

SwRI Estimate of the Emissions Levels of HD SI Engine

NOx = 0.05 g/hp-hrPM = 0.001 g/hp-hr NMHC = 0.07 g/hp-hrCO = 2.4 g/hp-hr

versus

NOx = 0.20 g/hp-hr PM = 0.01 g/hp-hr NMHC = 0.14 g/hp-hrCO = 15.5 g/hp-hr

HD SI Estimate

HD CI Standard

13

Heavy-Duty Diesel Emissions Standards

19880.600.60

NONOxx, G/HP, G/HP--HRHR

0.100.10

0.050.05

0.250.25

2.52.5 33 44 55 66

Part

icul

ate,

G/H

PPa

rtic

ulat

e,G

/HP --

HRHR

11 22

1991

199419982002

(NOx + HC)2007/20102007/2010

20142014

14

Heavy-Duty Diesel Emissions Standards

19880.600.60

NONOxx, G/HP, G/HP--HRHR

0.100.10

0.050.05

0.250.25

2.52.5 33 44 55 66

Part

icul

ate,

G/H

PPa

rtic

ulat

e,G

/HP --

HRHR

11 22

1991

199419982002

(NOx + HC)2007/20102007/2010

20142014

15

Engine Combustion Modes

Three Fundamental Modes of Combustion in Reciprocating Engines

Diffusion CombustionConventional DieselStratified Direct Injection SI

Flame Propagation CombustionConventional Gasoline SILean Burn SI

Homogeneous ReactionHCCI

16

Diffusion Burn Engines

17

Diffusion CombustionThe Future Diesel (~Y2010)

Advanced Fuel Systems, with high pressure injection ($) Advanced Controls ($), with engine tuned to keep aftertreatment devices Efficient PM Aftertreatment ($)NOx Afterteatment ($)UHC/HAPS Aftertreatment ($)The Result The Result -- Emissions are met, price goes Emissions are met, price goes way up, and efficiency suffersway up, and efficiency suffers……

BTE drops 10 percentage points

18

DIESEL EMISSIONS TECHNOLOGY EVOLUTION

As emissions levels become ever-more strict, the diesel engine efficiency will continue to drop

Y1997

Y2015

Y2002

Y20??Em

issi

ons

Leve

ls

Timeline1995 2000 2005 2010 2015 2020 2025 2030 2035

HD-Alternative Fuels become mandatory (?), because traditional diesel engine emissions cannot meet federal regulations?

Y2007

HD-Alternative Fuels become competitive

19

EPA-Ford Data

EPA/Ford MIT Workshop 11/02

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Massive EGR Diffusion Burn Engine(Alternative to NOx After treatment)

SwRI Has Extensive Data Base of 8-Mode Data for Cat 3176 2.5 g/hp-hr NOx + HC EngineUse Cycle Simulation to Model Different Levels of EGRAssumed LP Loop EGR After DPFConditions Examined

Baseline - Good Prediction of Existing DataBaseline A/F and Timing + EGR + BoostBaseline Timing + A/F=25:1 + EGR + BoostA/F=15:1 + EGR + Boost + Timing Advance

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Massive EGR

NOx

Test NameBase Variable 25to1 15to1

NO

x (g

/hp-

hr)

0.00.20.40.60.81.01.21.41.61.82.0

BSFC

Test Name

Base Variable 25to1 15to1B

SFC

(g/k

w-h

r)

100

120

140

160

180

200

220

Baseline Engine Around 2 g/hp-hrBSFC Penalty with Variable Due to Back Pressure Increases25:1 A/F Produced Lots of Turbine Energy15:1 A/F Lowered the Air Flow and Boost Requirements

22

Massive EGRIndependent Variables

Table 1. Independent Variables Examined in the Cycle Simulation Calculations

Test\Mode 1 2 3 4 5 6 7 8Baseline 70.13*

501003.2

46.2712.5103.42.8

22.196.1126.22.7

19.964.9186.92.8

44.8419.9125.54.8

32.4416.1166.24.6

31.76239.34.7

27.434.1288.27.6

Variable 70.13501003.2

46.2750103.42.8

22.1945215.72.7

19.9630253.82.8

44.84402004.8

32.44402804.6

31.7404403.1

27.433753015

25:1 70.13501003.2

2550103.42.8

25402402.7

25303102.8

25521254.8

25401904.6

25353004.7

25373807.6

15:1 70.13501003.2

1560103.42.8

15501602.7

15402402.8

157014020

155515015

155022015

15503007.6

* Listed are: A/F, Percent EGR, MAP (kPa), SOI (oCA)

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Massive EGRDependent Variables

Table 2. Dependent Variables Computed in the Cycle Simulations

Test\Mode 1 2 3 4 5 6 7 8Baseline 6.79*

1004412

3.802144917

2.971965690

2.851888164

1.862136120

1.441907763

2.6618211275

3.1417614829

Variable 6.791004412

1.222715327

0.041979133

0.1718810849

0.902359851

0.2820512930

0.3221821800

0.2420129184

25:1 6.791004412

0.052154507

0.1119110223

0.3018613352

0.032185619

0.091948590

0.1518813632

0.1318617573

15:1 6.791004412

0.0012274136

0.0012066512

0.00119810004

0.0012185907

0.0011957038

0.00118510875

0.00119313054

*Listed are: NOx (g/hp-hr), BSFC (g/kw-hr), and Pmax (kPa)

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Flame Propagation Engine

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Diffusion CombustionThe Future Diesel (~Y2010)

Advanced Fuel Systems, with high pressure injection ($) Advanced Controls ($), with engine tuned to keep aftertreatment devices Efficient PM Aftertreatment ($)NOx Afterteatment ($)UHC/HAPS Aftertreatment ($)The Result The Result -- Emissions are met, price goes Emissions are met, price goes way up, and efficiency suffersway up, and efficiency suffers……

BTE drops 10 percentage points

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Flame Propagation Combustion

BSFC

Emis

sion

s Le

vels

Diesel EngineLowering EmissionsBase Engine BSFC IncreasedAftertreatment BSFC Penalty

Spark Ignition EngineAdvanced Engine TechnologyThrottless, Miller Cycle, BoostedHigh BMEP, Efficient Catalysts

1998

2002

2010

2014

At What Emissions Level do the efficiencies Converge?

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Test SetupSpark ignition availableDiesel Micropilot ignition system (~1% fueling)Geometric Rc = 15/1LIVC Miller-cycle camshaft

Effective Rc = ~10/1 and ~12/1

Test FuelsDF-2 micropilot93 ON gasoline (Howell EEE)

CAT 3501 at SwRI

Further Details of Lab Setup

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The Research PathE

mis

sion

s

Efficiency

BaseEngine

BoostedEngine Advanced

Fueling

Exhaust GasRecirculation

(EGR)High

EnergyIgnitors

29

25

30

35

40

45

50

500 600 700 800 900 1000 1100BMEP (kPa)

Ther

mal

Effi

cien

cy (B

TE%

)

0.00

0.02

0.04

0.06

0.08

0.10

0.12

0.14

Engi

ne-O

ut N

OX

(g/h

phr)

NOx

CAT 3501RPM = 1200Phi = 1.0Fuel = Gasoline93 ON (R+M/2)Spark-Ignited

BTE

HD-Gasoline Results( High Energy Ignition )

High Energy, MicroPilot Ignited OperationNOx decreases as load is IncreasedEfficiency continues to increase with load

Better EGR toleranceIgnition-related misfires cured

Notice peak BTE approaching 35%, with potential for more...

ImprovedPeak Load

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HD-Gasoline Results( High Energy Ignition )

High Energy, MicroPilot Ignited OperationPeak EGR of 39%Engine Coefficient of Variance (COV) at normal levelsNo optimization of MP timing

Unburned hydrocarbons are an issue, but would be handled easily by 3-way catalyst

15

20

25

30

35

40

500 600 700 800 900 1000 1100BMEP (kPa)

EGR

(%)

Igni

tion

Tim

ing

(DB

TDC

)

0.0

1.0

2.0

3.0

4.0

5.0

6.0

7.0

CO

V of

IMEP

(%)

Unb

urne

d H

Cs

(g/h

phr)

UHCs

CAT 3501RPM = 1200Phi = 1.0Fuel = Gasoline93 ON (R+M/2)Spark-Ignited

MP IGN

COV of IMEP

EGR %

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Scaling HD-Gasoline Resultsto Approximate Multi-Cylinder

25

30

35

40

45

50

500 600 700 800 900 1000 1100 1200 1300

MEP (kPa)

Ther

mal

Effi

cien

cy (%

)

Single-CylinderBTE vs BMEP

Multi-CylinderEquivalentBTE vs BMEP

Single CylinderITE vs IMEP

CAT 3501 4LRPM = 1200Phi = 1.0Fuel = Gasoline93 ONDiesel Micropilot

39%39%

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Enabling Technologies

SwRI has identified technologies necessary to make SI competitive with dieselEnabling technologies identified through modeling and experimental studies

Boosted OperationHigh EGRHigh Energy Ignition SystemVariable Valve ActuationActive Fuel, VVA, and Knock Mitigation Controls

Possibly model+sensor based

33

Homogeneous Reaction Engines

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Homogeneous Reaction

HCCI will Remain a Part Load Option for Mixed Mode Engines as Long as Gasoline or Diesel Fuel are UsedPractical Full Time HCCI Operation will only be Possible When and HCCI Fuel is Available - See Last Year’s DEER

HCCI Multi-Cylinder EngineOperating Points Measured

0

200

400

600

800

1000

1200

500 1000 1500 2000 2500Speed (RPM)

Torq

ue (N

m)

HCCI Operation

Diesel Fuel

Gasolines

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HCCI Fuel Formulation - High Load

HCCI Fuel Formulation11.3 Bar NMEP0.02 g/kWh ISNOx

0.0 BSU Smoke

Highest load to dateStandard output Cummins Diesel approx. 15 Bar NMEP -

2,000

4,000

6,000

8,000

10,000

12,000

14,000

16,000

-60 -40 -20 0 20 40 60CAD

Cyl

. Pre

ssur

e (k

Pa)

66 RON

Motoring

Evolving HCCI Fuel Formulation

36

Conclusions

All Modes of Combustion Must be viewed as Potential Options for Meeting Future Emissions StandardsDiffusion Combustion Engines are Likely to Become Less Efficient and More Expensive

Aggressive EGR May HelpFlame Propagation Combustion Engines can Become More Efficient and More DurableFull Time HCCI Engines will Become Practical When there is a Specific HCCI Fuel