Effect of Exhaust Valve Timing on Combustion and Emissions of High Proportional Methanol-Gasoline Blends

GONG Yanfeng; QIAN Dingchao; MA Heyang; LIU Mingli; XIE Fangxi; MENG Xianglong

Vehicle Engine ›› 2025, Vol. 0 ›› Issue (1) : 12-17.

GONG Yanfeng¹,QIAN Dingchao¹,MA Heyang¹,LIU Mingli¹,XIE Fangxi²,MENG Xianglong²

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Abstract

The experiment was conducted on a high-compression ratio spark-ignition engine by using a self-developed variable valve mechanism and the effect of exhaust valve timing on the combustion and performance of methanol/gasoline engines with high volume methanol content was studied. It was found that early timing of exhaust valve would cause CA5 to lag and prolong the combustion duration. Combined with optimal ignition timing，the combustion phase improved. Under the combination of exhaust valve timing and optimal ignition timing, both b_e and NO_x emissions significantly improved. Under the optimal ignition timing, shifting the exhaust valve timing forward could reduce the optimal b_e of M50, M75, and M100 by 7.39%, 11.06%, and 18.72% respectively and NO_x emissions by 34.5%, 19.6%, and 23.9% respectively. Increasing the amount of methanol could also improve fuel economy and reduce HC emissions.

Key words

exhaust valve timing / methanol / gasoline / dual-fuel engine / fuel economy / emission

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GONG Yanfeng,QIAN Dingchao,MA Heyang,LIU Mingli,XIE Fangxi,MENG Xianglong. Effect of Exhaust Valve Timing on Combustion and Emissions of High Proportional Methanol-Gasoline Blends[J]. Vehicle Engine. 2025, 0(1): 12-17