小排量汽油机压缩比的选取

Selection of Compression Ratio for Small Displacement Gasoline Engine

由发动机原理我们知道,随着压缩比的增大会使燃烧的热效率提高,也可以使进气效率提高,发动机的功率、扭矩增大,有效燃油消耗率降低,但同时也会增加未燃混合气自燃的倾向。压缩比过大,热效率提高程度减慢,发动机燃烧粗暴,导致机件的机械负荷过大,排放污染严重。本文通过分析与试验给出不同压缩比对小排量汽油发动机的影响以及应用93号无铅汽油的合理压缩比的选取。

We know from the engine principle that with the increase of compression ratio, thermal efficiency and intake efficiency will improve, torque and power will increase and fuel consumption will decrease, but the tendency of serf-ignition of unburned gas mixture will also increase. Thermal efficiency increase extent will slow down when the compression ratio is too high. Rough engine combustion will result in too high mechanical load on parts and serious pollution emissions. This paper gives influence of different compression ratios on small-displacement gasoline engines through analyses and tests. How to select a reasonable compression ratio for RON 93# is also explained in the paper.