双燃烧模式发动机性能和排放特性对比的试验研究

Comparisons of Performances and Emissions of Dual Combustion Mode Engine

在一台经过改进的单缸发动机上实现了乙醇燃料火花点火(SI)燃烧和均质压燃(HCCI)燃烧。获得了两种燃烧方式各自的工作区,定义了乙醇HCCI燃烧的爆震边界和失火边界。研究结果表明,通过进气加热,仅靠空气稀释,乙醇燃料的HCCI燃烧工作上限最大达到了SI工作方式下的500/0。与火花点火相比,在乙醇HCCI燃烧的工作区域内,由于采用的是稀混合气,排气温度低,NOx的排放降低幅度达到580/0以上。发动机负荷越小,混合气变的更稀,缸内燃烧温度降低,NOx的降低幅度越大,但CO和HC的排放升高。

The spark ignition （SI） and homogeneous charge compression ignition （HCCI） were conducted alternatively in a modified single cylinder engine. The operation regions of the two combustion modes and the knock and/or misfire boundary were defined. Experimental resuhs show that the maximum load in HCCI mode is about half to that in SI mode load at the same speed solely diluted by preheated air. Compared with SI, the charge is lean in the operation region of Decreasing load leads to leaner er in CO and HC emissions. charge and lower combustion HCCI, and NO, emission decreases greatly. temperature in the cylinder, but slightly higher in CO and HC emissions.