Light-Duty Diesel NO
-HC-Particulate Trade-Off Studies
The emission control potential of typical divided chamber, light-duty Diesel engines was investigated by using engine dynamometer mapping tests, vehicle tests with engines modified to implement selected control strategies for reduced emission levels, experiments with combustion system modifications, and evaluations of techniques for the exhaust treatment of particulate emissions.
A dynamometer mapping program was conducted on a Diesel engine with a swirl chamber combustion system to determine the emission control capability with modulated EGR and fuel injection timing. Emission projections from mapping tests, confirmed by selected vehicle test results, indicated that the low mileage engineering objectives assumed for the .41/3.4/1.0/.6 gm/mi HC/CO/NOx/particulate emission level may be approached in experimental laboratory vehicles up to 3000 lb. inertia weight with optimized control systems. Particulate emissions limit the capability to meet the emission objective levels at higher inertia weights. Experimental Diesel combustion system modifications did not result in significant improvements in NOx, HC, and particulate emissions but caused a loss in fuel economy and/or power.
Techniques for collecting and periodically oxidizing particulate emissions were investigated. The regeneration of a particulate trap was achieved at a high load engine dynamometer operating condition during a steady state simulation of the AMA cycle.