喷油压力对直喷汽油机燃油湿壁的影响分析及优化研究

摘要

以某使用五孔喷油器的2.0 L缸内直喷发动机为研究对象,使用CONVERGE软件建立了定容弹喷雾和发动机缸内流动喷雾的数值计算模型,分析了燃油喷射压力对喷雾贯穿距和索特平均直径的影响,研究了燃油喷射压力对缸内湿壁现象的影响.使用段喷射策略对35 MPa燃油喷射压力时的燃油湿壁问题进行改善.结果表明,燃油喷射压力的提高会使油束贯穿距增大,从而导致燃油湿壁量明显增多,但采用3段喷射策略可以有效降低高压喷射下的燃油湿壁量.%A simulation model of a constant volume chamber was built to analyze the injection pressure influence on spray characteristics.A model of a 2.0L gasoline direct injection engine was built to analyze wall wetting.And triple-stage injection strategy was used to reduce the impingement at 35MPa injection pressure.The results show that the increase of fuel injection pressure can lead to the increase of penetration length and a significant increase of wall wetting fuel.And triple-stage injection strategy is effective to reduce wall wetting fuel.