中文摘要：

在一台经过改进的单缸机上分别实现了乙醇燃料均质压燃和火花点燃两种燃烧方式，获得了乙醇燃料两种燃烧方式各自的工作区域，并在不同工况实现了两种燃烧模式相互转换．为了改善SI／HCCI燃烧模式转换时的平顺性，考察了边界条件工况下火花点火对燃烧模式转换的影响．研究结果表明，在HCCI燃烧临界温度附近，引入火花点火能明显改善乙醇HCCI的燃烧稳定性，降低了燃烧循环变动．在SI／HCCI燃烧模式转换过程中，引入火花点火相当于向缸内混合气添加部分额外能量，以点燃混合气，进而改善了HCCI和SI相互转换时的平稳性．

英文摘要：

The spark ignition （SI） and homogeneous charge compression ignition （HCCI） have been realized in a modified single cylinder engine. The operation regions of the two combustion modes have been defined, and SI/HCCI combustion mode transitions under different operation conditions have been performed. The effects of spark on the combustion mode transition have been investigated in order to improve the smoothness of the transition. The results show that HCCI combustion stability has been improved gready and the combustion cycle-by-cycle variations decrease when the spark is utilized in the critical temperature operation conditions. During the transition process, the utilization of spark is equivalent to adding extra energy into the cylinder to ignite the mixrare, hence, the smoothness of the combustion mode transition has been enhenced.