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1、Fuels and Emissions: Lessons Learned in the U.S.,Lester Wyborny II U.S. Environmental Protection Agency Office of Transportation and Air Quality,Outline,Air Quality Concerns in the U.S. Emissions from Fuels: What we Learned from Emissions Testing Fuel Quality Enabling Emissions Control Overview of U
2、.S. Fuel Programs Conclusions,Air Quality Concerns in the U.S.,Why are we concerned about emissions from motor vehicles?,Air Quality Concerns in the U.S.,Congress established National Ambient Air Quality Standards (NAAQS) for Pb, SO2, NO2, CO, O3 and PM EPA recently revised the standards for Ozone a
3、nd PM Toxics reductions for cars/trucks required since the mid 90s,Air Quality Standards in the U.S.,The NAAQS Standards are: Lead 1.5 mg/M3 CO 35 ppm 1 Hr.; 9 ppm 8 Hr. SO2 0.03 ppm Yr.; 0.14 ppm Day; 0.50 1Hr NO2 0.053 ppm Yr Ozone 0.08 ppm 3 Yr. Avg. of 4th Highest 8 Hr.; was 0.12 ppm 1 Hr. PM2.5
4、 15 ug/M3 Yr.; 65 ug/M3 Day PM10 50 ug/M3 Yr.; 150 ug/M3 Day,Air Quality Standards in the U.S.,NO2 is no longer a health concern Pb is not a transportation issue SO2 is a secondary pollutant issue CO 15 counties still exceed the std. O3 26 areas do not or would not meet the 1 hr std. PM 15 areas vio
5、late the PM 10 std.,Emission Impacts of Fuels,How does changing fuel quality affect emissions of pollutants, or enable emissions control?,Emission Impacts of Fuels,Both Diesel and Gasoline powered engines have been tested with varying fuel quality. The testing has shown how fuel quality affects emis
6、sions of HCs, NOx and PM emissions.,Emission Impacts of Fuels,Fuel quality in diesel engines presented for three different engines: 1989 w/Mechanical fuel injection (SAE961074) 1999 w/Electronic fuel injection (SAE950251) 2002 w/Electronic FI and Cooled EGR (HDEWG http:/transaq.ce.gatech.edu/epatac/
7、heavy/heavy.htm) All are without aftertreatment, with moderate/high pressure fuel injection.,Emission Impacts of Fuels,Emission Impacts of Fuels,Emission Impacts of Fuels,Sulfur, Aromatics, T-95 and cetane have been shown to impact PM emissions. Density, poly and total aromatics, and cetane number h
8、ave been shown to impact NOx emissions. The emissions effects of changes to each of these fuel qualities are generally between zero and 10%.,Emission Impacts of Fuels,EPA is evaluating the impact of diesel fuel quality on emissions through a literature search. This review is expected to be completed
9、 in the next few months. The results of the study will be posted on the Web: http:/www.epa.gov/otaq/models/ analysis.htm,Emission Impacts of Fuels,Significant testing program of 1990 gasoline vehicles was made for the RFG program. Vehicles were either FI or Carbureted equipped with catalysts. Also,
10、testing of high emitters. Testing was later completed on NLEVs.,Emission Impacts of Fuels,Emission Impacts of Fuels,Source: Unconsolidated Complex Model and Tier 2 Rule,Emission Impacts of Fuels,Because gasoline powered cars in the U.S. use catalysts, sulfur is important in reducing emissions. RVP c
11、ontrol is important for evap emissions from nonregulated cars and from high emitters. Other fuel qualities are less important.,Enabling Emissions Control,For emissions control of both diesel fuel and gasoline-powered vehicles, enabling emissions control hardware with improved fuel is crucial. Exampl
12、es: Lead phase-down, Sulfur control of gasoline and diesel fuel, Improved engine oil formulations, and Fuel additives.,Enabling Emissions Control Gasoline Cars and Trucks,For Catalyzed Cars, Lead Removal is Necessary,Sulfur Reduction is Necessary for Advanced Tech Cars,Enabling Emissions Control Gas
13、oline Cars and Trucks,Phase-down of Lead was necessary to allow the use of catalysts, also it improved spark plug life. Lead cannot be added to gasoline and it must be 0.05 g/gal. Potential damage to soft valve seats in older cars did not materialize, so phase-in is not necessary.,Enabling Emissions
14、 Control Gasoline Cars and Trucks,Sulfur reduction allows catalysts and O2 sensors to operate efficiently. Lower sulfur is helpful with lower tech engines and is necessary with higher tech engines. Lower sulfur reduces NOx, HC and CO emissions.,0,0.1,0.2,0.3,0.4,0.5,0.6,0.7,g/hp-hr,1988,1991,1994,tr
15、uck,bus,Catalyzed PM Trap based 0.01 g/bhp-hr Requires 15 ppm sulfur,2007,Enabling Emissions Control PM Standards for Diesel Engines,Based on Oxidation Catalysts Required 500 ppm Sulfur,Enabling Emissions Control NOx Standards for Diesel Engines,0,2,4,6,8,10,12,g/hp-hr, uncontrolled levels,1990,1991
16、,1998,2004,1985,NOx aftertreatment 0.2 g/bhp-hr Requires 15 ppm Sulfur,2007,Cooled EGR 500 ppm Sulfur is Probably Necessary,Enabling Emissions Control Diesel Quality Impacts on Emissions from 2007 Engines,NOx,PM,Enabling Emissions Control NOx Emissions,Enabling Emissions Control PM Emissions,Enabling Emissions Control Lower Sulfur and Lower Emissions,Sulfur reduction helps to enable cooled EGR for NOx control. Deep sulfur reduction is necessary for
