Experimental study the effect of injection strategies on combustion and emission characteristics in gasoline compression ignition engines using gasoline/hydrogenated catalytic biodiesel blends

Abstract A new type of fuel named hydrogenated catalytic biodiesel blended with gasoline is proposed to apply in a gasoline compression ignition engine for low-temperature combustion. However, the higher maximum pressure rise rate and retarded combustion phasing under high loads of single injection mode are the main problems. Hence, the double injection strategy is proposed to solve the above problems and to find the optimal injection conditions for this tested fuel. The combustion and emission characteristics are tested at high load by varying different pilot injection ratio from 20 to 30% and pilot injection timing from −60 to −40 °CA aTDC for this test fuel. The results show that increasing pilot injection ratio can advance the combustion phasing, while it increases the maximum pressure rise rate. −50 °CA aTDC of pilot start of injection timing has advanced combustion phasing and higher maximum pressure rise rate than that of −40 and −60 °CA aTDC conditions. Moreover, the NOx emission is mainly effect by pilot ratio, while PM, THC and CO emissions are controlled by pilot start of injection timing. 30% of pilot ratio with −50 °CA aTDC of pilot start of injection timing is an optimal injection strategy for G80H20 and G70H30 blends considering combustion and emission characteristics.