An experimental study of pre-main injection strategy to optimize TDI diesel engine

Reducing emissions and fuel consumption have always been a major concern of engine manufacturers. In recent years, strict emission laws and fast reduction of fossil fuel resources have increased this concern. Main purpose of this work is to optimize D87 diesel engine with consideration of parameters such as amount of soot emission, BSFC and maximum pressure of combustion chamber. Effect of pre injection on engine performance has been investigated experimentally. Test is done for four different load points in constant maximum speed which at each load point 3 up to 7 percent of total fuel mass is considered in pilot injection. Results show that BSFC is decreased with increasing of pre injected fuel. From the other side soot emission and maximum pressure of combustion chamber are increased by increasing of pre injected fuel, but both of them are still in an acceptable level so the optimum point is selected based on the minimum BSFC. In all cases minimum BSFC is reached by considering 7 percent of total fuel mass in pre injection which the minimum amount of BSFC is about 194 g/kW.h at 1000 kW.