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针对一般直喷式汽油机燃烧系统设计复杂的问题,研究开发了一种以两段喷射作为分层稀燃混合气形成主要手段的汽油缸内直喷式燃烧系统。该文用三维模拟计算和试验的方法研究了两段喷射控制分层混合气形成的基本规律。研究结果表明:一次喷油时刻存在着最佳值,过早过晚都使喷雾碰壁,不利于混合气的形成和燃烧。二次喷油时刻也存在最佳值,在进气上止点后250°CA进行二次喷油,可使火花塞周围的混合气在点火时刻较适宜,有利于点火。两次喷射油量之比对混合气的形成有显著影响,当其控制在1/3左右时,缸内混合气的分层结构较为合理。
Aiming at the complicated design problem of general direct injection gasoline engine combustion system, a direct injection combustion system of gasoline cylinder with two stages of injection as stratified lean-burn gas mixture is researched and developed. In this paper, three-dimensional simulation calculation and experimental study of the two-stage injection control stratified mixture formation of the basic law. The results show that there is an optimum value for the time of fuel injection. If the fuel injection happens to be too early or too late, it is not conducive to the formation and combustion of the gas mixture. The second injection time there is also the best value, the intake after the top dead center 250 ° CA for the second fuel injection, the mixture around the spark plug at the ignition timing more appropriate, is conducive to ignition. The ratio of the two injection quantities has a significant effect on the formation of the mixture. When the control is about 1/3, the layered structure of the mixture in the cylinder is more reasonable.