当首循环混合气浓度过浓或者是过稀时，瞬态hc排放迅速增加。
The HC emissions are increased remarkably when the mixture concentration becomes too lean or too rich.
试验结果表明：LPG发动机成功起动所需的混合气浓度比汽油发动机的稀。
The results showed that the fuel-air mixture suitable for the LPG engine start is leaner than that of the gasoline engine.
模拟计算表明，利用早喷可以形成稀薄准均质混合气；燃烧室形状影响混合气浓度场和温度场。
The results show that the lean quasi-homogeneous mixtures can be formed by early-injection, and the shape of combustion chamber has an obvious effect on density and temperature fields of mixture.
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