The performances of diesel engine are improved by higher swirl in the operating range of low speed and high load.

在高速区降低进气涡流强度，发动机的性能和排放均有明显改善。

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The results show that the best operating region of HCCI engine is related to the engine load, speed, and the mixture excess air ratio.

研究结果表明：均质充量压缩着火发动机的最佳工作范围与发动机转速混合气过量空气系数和负荷有密切的关系；

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The mixture must be of varying degrees of richness to suit engine operating conditions. It must be rich (have a higher percentage of fuel) for starting, acceleration, and high-speed operation.

混合气的浓度比例可以改变，以适应发动机的运行状况。汽车在启动、加速和高速行驶时，需要含燃油浓度较高的混合气；

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