Improvement of combustion and emission by combined combustion of ethanol premix and gasoline direct injection in SI engine

In this paper, a test platform for ethanol port injection plus gasoline direct was built to explore the effects of different ethanol-gasoline ratios (Re), timing (DIT) and ignition (IT) on combustion emissions SI engine. Results clearly show that when total fuel contains more ethanol, corresponding maximum torque is smaller than gasoline. Compared with sole (EPI) mode (GDI) mode, G25 EPI + GDI best high-efficiency IT = 20°CA BTDC DIT 120°CA can be regarded as optimal operating condition highest output, braking thermal efficiency lowest BSFC. As exhaust emissions, CO HC reach at while NOx has an opposite trend. Delayed within range 10-30°CA reduces emissions. particle number size peak gradually decreases from G100 G0, accumulation (APN) further oxidized shows significant downward trend increase ethanol. The TPN obtained in which dropped by 9% 85% respectively compared mode. When Re ≥ 50%, nucleation (NPN) distribution higher number, there result Re＜50%. Overall, findings paper make contributions development low-pollution combined engines promote application clean alternative fuels.