燃烧边界条件对乙醇均质压燃燃烧的影响

Influences of Combustion Boundary Conditions on 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燃烧边界条件对乙醇燃料均质压燃(HCCI)燃烧过程影响的试验研究。结果表明,在转速和进气温度一定时,随着过量空气系数的增加,着火始点推迟,燃烧持续期变长,缸内的最大燃烧压力降低,放热率降低,(?)_(50)(50%乙醇燃烧放热量所在的曲轴转角)位置推迟,燃烧效率降低；在发动机转速、进气温度和过量空气系数一定时,随着EGR率的升高,着火始点推迟,燃烧持续期延长,(?)_(50)位置推迟,放热速率降低,压力升高率变小,缸内最大燃烧压力减小,燃烧效率降低。在转速和供油量一定时,随着进气温度的升高,着火始点提前,燃烧持续期变短,压力升高率变大,缸内的最大燃烧压力变大。得到了发动机转速、过量空气系数和对应于最大指示热效率点的进气温度间的MAP图。

The influences of combustion boundary conditions on ethanol homogeneous charge compression ignition （HCCI） combustion were investigated. The experiments were carried out on a modified CA6110 engine. For the fixed engine speed and intake temperature, with the increase of air/fuel equivalence ratio, the initial point of combustion postpones, the combustion duration increases, the maximum cylinder pressure increases and the combustion efficiency decreases. While with the increase of EGR ratio, the same behaviors are presented in combustion parameters. For fixed engine speed and fuel supplying amount, with the increase of intake temperature, the phasing of combustion occurs earlier, combustion duration decreases, the rate of pressure rise increases and the maximum cylinder pressure increases. The MAP of the engine speed, air/fuel equivalence ratio and intake temperature for achieving maximum indicated thermal efficiency is obtained.