乙醇燃料SI-HCCI-SI燃烧模式转换过程的研究

Study on the Transition Mode of Ethanol SI-HCCI-SI Combustion Mode Transition

在一台单缸试验机上进行了乙醇燃料均质压燃(HCCI)和火花点燃(SI)两种燃烧模式相互转换的试验研究。结果表明,采用进气热管理系统,可以实现乙醇燃料在两种燃烧方式间的转换。在SI向HCCI转换过程中,由于混合气瞬间变稀,而高温热气进到缸内有一定的时间,转速和平均有效压力下降,经过约4个工作循环后,随着高温热气连续、均匀地进到缸内,实现了连续稳定的HCCI燃烧,因此转速和平均有效压力上升,并且很快达到稳定。在HCCI向SI转换过程中,由于存在火花点火,对混合气的温度不是很敏感,因此过渡时间减少,发动机很快达到稳定状态。

Mode transition of ethanol combustion between homogeneous charge compression ignition （ HCCI） and spark ignition （SI） was investigated in a single cylinder diesel engine. Experimental resuhs showed that combustion mode transition could be realized with the Fast-Thermo Management system. During the transition process form SI to HCCI, the mixture becomes the leaner and a time is needed for the homogeneous charge of high temperature entering into the cylinder, leading to decrease in engine speed and mean effective pressure. After 4 cycles, with the entering of high temperature intake charge into the cylinder, the HCCI combustion is realized and increases the engine speed and the mean effective pressure and engine is operated stably. During the transition process form HCCI to SI, with aid of spark ignition, the transition period decreases and engine quickly gets its stable operation.