重庆理工大学学报2025，Vol.39Issue(5)：177-185,9.DOI:10.3969/j.issn.1674-8425(z).2025.03.023
不同转速下循环波动对SI发动机爆震燃烧影响的大涡模拟研究
Large eddy simulation study on the effect of cycle-to-cycle variation of SI engine knocking combustion at different rotational speeds
摘要
Abstract
Small reinforced gasoline engines achieve impressive power performances and excellent fuel economy,it suffers severe knocking problems.Our study is based on large eddy numerical simulation coupled with the G-equation model.We take knock combustion of spark ignition engines as the research object.The relationship between the cyclic fluctuation characteristics of SI engines and end gas spontaneous combustion and knock generation at different speeds is analyzed.Our results show,under the fixed spark ignition timing,the increase in rotational speed reduces the propagation speed of the main flame within the crankshaft corner time.The average fuel mass fraction point of 50%at a speed of 4000r/min is delayed by 4 ° compared to 3000r/min,resulting in a delay in the onset of knocking.Meanwhile,our findings show the different flame development rates in the early stages of combustion are the main reasons for the variations in knock intensity and end point auto-ignition time between cycles.Cycles with faster flame propagation speeds in the early stages are more likely to exert compression on the end gas,thereby promoting the formation of auto-ignition points.Moreover,the coupling effect between multiple auto-ignition nuclei,cylinder pressure,and chemical reactions leads to higher knock intensity.The pressure wave peak generated by the first auto-ignition point is often the highest while the pressure wave intensity of subsequent auto-ignition points is relatively low due to insufficient mixture participation in chemical reactions.关键词
汽油发动机/循环波动/发动机爆震/发动机转速/大涡模拟/末端自燃Key words
spark-ignited gas engine/cycle-to-cycle variation/engine knock/engine rotational speed/large-eddy simulation/auto-ignition分类
能源科技引用本文复制引用
潘明章,李振义,莫海俊,叶年业,官维,满兴家..不同转速下循环波动对SI发动机爆震燃烧影响的大涡模拟研究[J].重庆理工大学学报,2025,39(5):177-185,9.基金项目
中央高校基本科研业务费资助项目(自然科学类)(300102383503) （自然科学类）
广西重点研发计划项目(桂科AB22080084) （桂科AB22080084）
