Effects of Fischer-Tropsch diesel fuel on combustion and emissions of direct injection diesel engine

Abstract

Effects of Fischer-Tropsch (F-T) diesel fuel on the combustion and emission characteristics of a single-cylinder direct injection diesel engine under different fuel delivery advance angles were investigated. The experimental results show that F-T diesel fuel exhibits shorter ignition delay, lower peak values of premixed burning rate, lower combustion pressure and pressure rise rate, and higher peak value of diffusion burning rate than conventional diesel fuel when the engine remains unmodified. In addition, the unmodified engine with F-T diesel fuel has lower brake specific fuel consumption and higher effective thermal efficiency, and presents lower HC, CO, NO _x and smoke emissions than conventional diesel fuel. When fuel delivery advance angle is retarded by 3 crank angle degrees, the combustion duration is obviously shortened; the peak values of premixed burning rate, the combustion pressure and pressure rise rate are further reduced; and the peak value of diffusion burning rate is further increased for F-T diesel fuel operation. Moreover, the retardation of fuel delivery advance angle results in a further significant reduction in NO _x emissions with no penalty on specific fuel consumption and with much less penalty on HC, CO and smoke emissions.