Investigation the impact of injection timing and pressure on emissions characteristics and smoke/soot emissions in diesel engine fuelling with soybean fuel

Abstract

Engine injection strategy and renewable fuel both can improve nitrogen oxides (NO_X) and smoke/soot emissions in a common-rail compression ignition (CI) diesel engine. The effect of different post-injection (PI) timings (15, 30 and 45) and injection pressures (550 and 650 bar) on pollutant emissions and smoke/soot emissions were investigated from combustion renewable fuel (soybean biodiesel). The results showed that the levels of carbon monoxide (CO), hydrocarbons (HCs) and NO_X reduced from the combustion of soybean biodiesel compared to the diesel fuel combustion for different injection strategy. Besides, NO_X emission is clearly reduced with retarded PI timing, especially at 45° after top dead centre (aTDC). It is found that the increasing injection pressure reduced gaseous emissions for both fuels. The combination between biodiesel fuel and injection strategy can provide meaningful improvements in pollutant emissions as well as enhance the exhaust temperature compared to the diesel fuel. With biodiesel fuelling, smoke/soot emissions were reduced from biodiesel combustion (by 19.7%) under different fuel injection timings and pressures than to the diesel fuel combustion (by 12.2%).