Diesel Engines: Environmental Impact and Control Alan C. Lloyd, Ph.D. California Air Resources Board DEER Conference 2002
Diesels are an Important Part of the World s Economy Land and sea transport Electrical power Farming, industrial, and construction activities Introduction
Introduction Diesels Make Up One-Third of Passenger Car Sales in Europe Percent of New Car Sales 35% 30% 25% 20% 15% 10% 5% 0% 1980 1985 1990 1995 2001 Source: Walsh (2001) SAE paper 2001-01-0183 Sales Year
Diesel Truck VMT is Growing in the U.S. Annual VMT (billions) 140 120 100 1992 1997 80 60 40 20 0 <10,000 10,001 to 19,500 19,501 to 26,000 Truck Average Weight Category (pounds) Source: U.S. Department of Commerce >26,000 Introduction
Emissions Diesel Will be a Major Source of NO X in California Other Mobile Sources 32% On-Road HDD 18% Off-Road Diesel 19% Source: EMFAC2001 v2.082 Stationary 31% California in 2010
Diesel is a Majority of Air Toxic Risk in Los Angeles Risk (excess per million) 1800 1600 1400 1200 1000 800 600 400 200 0 1990 2000 Greater Los Angeles Other Toxics Diesel PM Emissions
CA Diesel Vehicle NO X Inventory NO X (thousand tons/year) 350 300 250 Heavy-duty Vehicles 200 150 Non-road Vehicles 100 50 0 Medium-duty Vehicles 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 ARB EMFAC 2001 v2.08 Year Emissions
CA Diesel Vehicle PM10 Inventory PM10 (thousand tons/year) 14 12 10 Heavy-duty Vehicles 8 6 4 2 0 Non-road Vehicles Medium-duty Vehicles 1970 1975 1980 1985 1990 1995 2000 2005 2010 2015 2020 ARB EMFAC 2001 v2.08 Year Emissions
Cancer Effects of Diesel Increased lung cancer incidence supported by 30+ population studies. WHO, U.S. EPA, NIOSH, and HEI acknowledge the cancer potential in humans. ARB identified diesel exhaust PM as TAC. Unit Risk Range: 130-2,400 per million. Health Effects
2.1 2.08 2.06 2.04 2.02 2 1.98 1.96 Association Between Lung Function of Children Living <300 Meters From Motorway and Intensity of Cargo Traffic Lung Function FEV1 (Liters) 5000 7000 9000 11000 13000 15000 17000 19000 Number of Heavy Duty Vehicles Per Working Day Source: Brunekreef B, et al, Air Pollution from truck traffic and lung function in children living near motorways Health Effects
Diesel Contributes to Water and Soil Pollution Fuel spills and leaks. Deposition to water bodies and soils. Environmental Effects
Emissions From Diesels Can 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 Controls
Engine Technologies That Reduce Diesel Emissions In-Cylinder Air Handling Fuel Handling Aftertreatment PM Traps NOx Catalysts Electronic control Emission Controls
NO X (g/bhp-hr) 12 10 8 6 4 2 0 Stringent NOx Standards Exist for New On-Road Engines Source: DieselNet. Emissions Standards: European Union, 2001. U.S./CA EU 1988 1990 1992 1994 1996 1998 2000 2002 2004 2006 2008 2010 Current and Future Technologies
PM (g/bhp-hr) 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 1988 Stringent PM Standards Exist for New On-Road Engines 1990 1992 1994 1996 1998 2000 2002 2004 2006 Source: DieselNet. Emissions Standards: European Union, 2001. U.S./CA EU 98+% lower 2008 2010 Current and Future Technologies
More Stringent Emission Standards For New Off-road Engines Needed 8 7 7.9 175-300 hp g/bhp-hr 6 5 4 3 4 4.9 3 HC+NOx PMx10 2 1.5 1.5 1 0.34 0.1 0 1996 2003 2006 2007 HDDE* Model Year *2007 HDDE Standards are 0.2 g/bhp-hr NOx and 0.14 g/bhp-hr NMHC Emission Controls
Diesel Fuels Low 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 Fuels Fischer Tropsch - zero sulfur and aromatics Water emulsions - reduce PM and NO X Future Technologies
California Diesel PM Risk Reduction Plan Sets Aggressive Goals 75% risk reduction by 2010. Retrofit on- and offroad diesel engines with filters (80% of plan s benefit). Future Technologies
Maintaining Low Emissions In-use Through Enforcement Roadside smoke inspections. Reduced smoky trucks from 30% to 8%. Expand to include NO X and PM. Manufacturer-run in-use compliance program. Future Technologies
Diesel PM Traps Can Be Effective Trap Trap Trap Future Technologies
Alternative Fuels Can Reduce Emissions Natural Gas Lower NO X and PM. Nanoparticle formation being investigated. Methanol and Ethanol Poor durability and frequent overhauls. Future Technologies
Fuel Cells Have Promise Ultimate replacement for diesel engines: Zero Emissions High efficiency Cost reduction needed Initial transit buses in 2003. Near-term promise as truck APU. Future Technologies
Progress Means Continued Regulation and Monitoring Environmental regulations result in reduced emissions. Equal focus on off-road engines and fuels needed. Monitoring of in-use emission performance must continue. Conclusions and Recommendations
Summary 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.
Summary (cont d) Technology is advancing to meet these challenges. Existing engines need to be cleaned up. Retrofit and replacement programs are being developed.