Diesel Engines: Environmental Impact and Control

Alan C. Lloyd, Ph.D.California Air Resources Board

DEER Conference 2002

IntroductionIntroduction

•Land and sea transport

•Electrical power

•Farming, industrial, and construction activities

Diesels are an ImportantDiesels are an ImportantPart of the World’s EconomyPart of the World’s Economy

IntroductionIntroduction

0%

5%

10%

15%

20%

25%

30%

35%

1980 1985 1990 1995 2001

Sales Year

Percent of New Car Sales

Diesels Make Up OneDiesels Make Up One--Third of Third of Passenger Car Sales in EuropePassenger Car Sales in Europe

Source: Walsh (2001) SAE paper 2001-01-0183

IntroductionIntroduction

Diesel Truck VMT is Diesel Truck VMT is Growing in the U.S.Growing in the U.S.

0

20

40

60

80

100

120

140

<10,000 10,001 to 19,500

19,501 to26,000

>26,000

Truck Average Weight Category (pounds)

19921997

Annual VMT (billions)

Source: U.S. Department of Commerce

Diesel Will be a Major Source ofDiesel Will be a Major Source ofNONOXX in Californiain California

Other Mobile Sources

32%

Off-Road Diesel19%

Stationary31%

On-Road HDD18%

California in 2010Source: EMFAC2001 v2.082

EmissionsEmissions

Diesel is a Majority of Air Toxic RiskDiesel is a Majority of Air Toxic Riskin Los Angelesin Los Angeles

0200400600800

10001200140016001800

Ris

k (e

xces

s pe

r m

illio

n)

1990 2000

Other Toxics

Diesel PM

Greater Los Angeles

EmissionsEmissions

0

50

100

150

200

250

300

350

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

CA Diesel Vehicle CA Diesel Vehicle NONOXX InventoryInventory

NOX (thousand tons/year)

Heavy-duty Vehicles

Non-road Vehicles

Medium-duty Vehicles

YearARB EMFAC 2001 v2.08 EmissionsEmissions

0

2

4

6

8

10

12

14

1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020

CA Diesel Vehicle CA Diesel Vehicle PM10 InventoryPM10 Inventory

PM10 (thousand tons/year)

Heavy-duty Vehicles

Non-road Vehicles

Medium-duty Vehicles

YearARB EMFAC 2001 v2.08 EmissionsEmissions

Health EffectsHealth Effects

Cancer Effects of DieselCancer Effects of Diesel

ØIncreased lung cancer incidence supported by 30+ population studies.

ØWHO, U.S. EPA, NIOSH, and HEI acknowledge the cancer potential in humans.

ØARB identified diesel exhaust PM as TAC.

ØUnit Risk Range: 130 - 2,400 per million.

Association Between Lung Function of Association Between Lung Function of Children Living <300 Meters From Children Living <300 Meters From

Motorway and Intensity of Cargo TrafficMotorway and Intensity of Cargo Traffic

1.96

1.98

2

2.02

2.04

2.06

2.08

2.1

5000 7000 9000 11000 13000 15000 17000 19000

Number of Heavy Duty Vehicles Per Working Day

Lung FunctionFEV1 (Liters)

Health EffectsHealth Effects

Source: Brunekreef B, et al, Air Pollution from truck traffic and lung function in children living near motorways

Environmental EffectsEnvironmental Effects

Fuel spills and leaks.

Deposition to water bodies and soils.

Diesel Contributes to Water Diesel Contributes to Water and Soil Pollutionand Soil Pollution

Emissions From DieselsEmissions From DieselsCan be ReducedCan be Reduced

New Engines– Engine improvements /– electronic controls– Post-combustion clean-up– Alternatives to diesel

Fuels– Cleaner diesel– Alternatives

Current fleet– Proper maintenance– Retrofit

Emission ControlsEmission Controls

In-Cylinder

•Air Handling

•Fuel Handling

•Electronic control

Aftertreatment

•PM Traps

•NOx Catalysts

Engine Technologies That Engine Technologies That Reduce Diesel EmissionsReduce Diesel Emissions

Emission ControlsEmission Controls

Stringent NOx Standards ExistStringent NOx Standards Existfor New Onfor New On--Road EnginesRoad Engines

Current and Future TechnologiesCurrent and Future Technologies

NOX (g/bhp-hr)

Source: DieselNet. Emissions Standards: European Union, 2001.

0

2

4

6

8

10

12

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

U.S./CAEU

Stringent PM Standards ExistStringent PM Standards Exist

for New Onfor New On--Road EnginesRoad Engines

Current and Future TechnologiesCurrent and Future Technologies

PM (g/bhp-hr)

Source: DieselNet. Emissions Standards: European Union, 2001.

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

1988

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

U.S./CAEU

98+% lower

More Stringent Emission StandardsMore Stringent Emission StandardsFor New OffFor New Off--road Engines Neededroad Engines Needed

7.9

4

4.9

1.5

3

1.5

0.340.1

0

1

2

3

4

5

6

7

8

g/b

hp

-hr

1996 2003 2006 2007 HDDE*

HC+NOxPMx10

175-300 hp

Model Year*2007 HDDE Standards are 0.2 g/bhp-hr NOx and 0.14 g/bhp-hr NMHC

Emission ControlsEmission Controls

Diesel Fuels

Low Sulfur FuelLow Sulfur Fuel•Needed for aftertreatment

•U.S. - 15 ppm (on-road) by mid-2006

•CA/TX - 15 ppm (on and off-road) by mid-2006

•EU - 50 ppm by 2005 (possibly 10 ppm)

Alternative Diesel FuelsAlternative Diesel Fuels•Fischer Tropsch - zero sulfur and aromatics

•Water emulsions - reduce PM and NOX

Future TechnologiesFuture Technologies

75% risk reduction by 2010.

Retrofit on- and off-road diesel engines with filters (80% of plan’s benefit).

California Diesel PM Risk Reduction California Diesel PM Risk Reduction Plan Sets Aggressive GoalsPlan Sets Aggressive Goals

Future TechnologiesFuture Technologies

•Roadside smoke inspections.

•Reduced smoky trucks from 30% to 8%.

•Expand to includeNOX and PM.

•Manufacturer-run in-use compliance program.

Maintaining Low Emissions InMaintaining Low Emissions In--use use Through EnforcementThrough Enforcement

Future TechnologiesFuture Technologies

Trap

Trap

Diesel PM Traps Can Be EffectiveDiesel PM Traps Can Be Effective

Trap

Future TechnologiesFuture Technologies

Natural GasNatural Gas

•Lower NOX and PM.

•Nanoparticle formation being investigated.

Methanol and EthanolMethanol and Ethanol

•Poor durability and frequent overhauls.

Alternative FuelsAlternative FuelsCan Reduce EmissionsCan Reduce Emissions

Future TechnologiesFuture Technologies

Ultimate replacement for diesel engines:

• Zero Emissions

• High efficiency

• Cost reduction needed

Initial transit buses in 2003.

Near-term promise as truck APU.

Fuel Cells Have PromiseFuel Cells Have Promise

Future TechnologiesFuture Technologies

Conclusions and RecommendationsConclusions and Recommendations

•Environmental regulations result in reduced emissions.

•Equal focus on off-road engines and fuels needed.

•Monitoring of in-use emission performance must continue.

Progress Means Continued Progress Means Continued Regulation and MonitoringRegulation and Monitoring

SummarySummary

•Diesels are a key power source.

•Diesels are significant contributors to air pollution.

•Diesel exhaust is linked to cancer.

•Regulations are in place for new on-road diesels.

•Comparable regulations are needed for off-road, including cleaner fuel.

SummarySummary ((cont’dcont’d))

•Technology is advancing to meet these challenges.

•Existing engines need to be cleaned up.

•Retrofit and replacement programs are being developed.