乙醇燃料均质压燃的燃烧循环变动

Cycle-by-cycle variation of ethanol homogeneous charge compression ignition combustion

在一台由CA6110柴油机改造而成的单缸发动机上进行了乙醇燃料均质压燃燃烧循环变动的研究。结果表明:随着过量空气系数增大,最大燃烧压力、平均指示压力、燃烧持续期的循环变动均增大,燃烧始点的标准偏差减小。随着进气温度的升高,最大燃烧压力升高,而平均指示压力先升高后下降,两者的循环变动均减小,燃烧始点的循环变动增大,燃烧持续期缩短,循环变动减小。引入适量的EGR能显著地改善燃烧速率,降低最大压升率,但EGR过大会使混合气不能稳定、连续地着火燃烧。

The cycle-by cycle variations of the ethanol homogeneous charge compression ignition （HCCI） combustion have been investigated in a single cylinder engine modified from a CA6110 diesel engine. The experiment results show that as the air/fuel ratio increases, all of the cycle-by-cycle variations of the maximum pressure, the mean indicated pressure, and the combustion duration period increase, but the stand deviation of start of combustion （SOC） decreases. As the intake charge temperature rises, the maximum pressure increases, but the mean indicated pressure increases firstly and then drops, and their cycle by cycle variations decrease; the cycle-by-cycle variation of the SOC increases, and combustion duration period shortens, its variation decreases. Proper amount EGR inducted can dramatically enhance the combustion rate and decrease the pressure rise rate, but too much EGR would result in unstable even intermittent combustion.