Effects of Pilot Injection Strategy on Combustion and Emission Characteristics in Gasoline Compression Ignition

In this paper, the effects of pilot injection strategies, including various pilot injection timings and masses, on the combustion and emission characteristics of gasoline compression ignition are investigated in a multi-cylinder heavy duty diesel engine with the aim of reducing peak pressure rise rate while improving thermal efficiency and exhaust emissions. The results show that the IIRRN, max (peak heat release rate of pilot injection) becomes more sensitive to the change of pilot-main interval as the pilot injection mass increases, and the sensitivity of HRRpr max to the change of pilot injection mass increases with the reduction of pilot-main interval. PHRRMI, max (peak premixed heat release rate of main injection) decreases with the decrease of pilot-main interval and the increase of pilot injection mass. The PRRmax (peak pressure rise rate) and soot emission can be improved by 60.2% and 42.3% respectively, while still maintaining similar BSFC with optimized pilot injection strategy compared to single injection. (C) 2017 The Authors. Published by Elsevier Ltd.