Effects of EGR on Emission Characteristics of LowDuty Engine Fueled with Biodiesel

Abstract:

Based on a common rail diesel engine with cooling EGR and fueled with biodiesel, an experiment about the coupled effects of EGR and main injection time on engine emissions characteristics was conducted. The results show that at full load, the NOxemission increases, but THC emission and ultra particulate concentration decrease when the engine is fueled with biodiesel. At a load of 25% and a speed of 2 200 r?min-1, when the EGR rate increases, NOx emission, ultraparticulate concentration, THC emission and BSFC (brake specific fuel consumption) decrease. However, with the main injection time retarded, NOx emission and ultraparticulate concentration also decrease, but THC emission and BSFC increase. At a load of 25%, with the EGR rate increasing and main injection time retarded, NOx emission, ultraparticulate concentration decrease, but THC emission and BSFC increase. The effect of main injection time on ultraparticulate concentration is not so significant. Considering both emission and BSFC, at a load of 25%, a 26% of EGR and a main injection time of 7.7° CA BTDC are chosen. At a load of 50%, a 18% of EGR and a main injection time of 6.3° CA BTDC are chosen.