LPG在点燃式发动机上的稀限判别

Judgement of Lean Burn Limit for SI Engine Using LPG

介绍了LPG在小型点燃式发动机上应用时稀限判别方法的定义与选取。研究结果表明 :扭矩波动、转速波动、HC排放值和HC升高率都受空燃比的影响 ,并且它们的变化趋势具有较好的一致性 ;随着空燃比的变化 ,转速波动变化不明显 ,受发动机结构参数和运行参数的影响 ,用于判别稀限的HC排放值较难确定 ,因此把扭矩波动和HC升高率作为稀限的判断条件比较合理。

Definition and the selection of lean burn limit in small SI LPG engine is studied.Test results show that fluctuation of torque output and engine speed,HC emission and its rise ratio are all affected by excess air ratio.Change of those parameters appears to have similar trend versus excess air ratio except fluctuation of engine speed which is not prominent.It is found that the HC emission level is invalid to use as a judgment criterion for lean burn limit.Fluctuation of torque output and rising ratio of HC emission are sensitive to excess air ratio to be selected as parameters to judge LPG engine lean burn limit.