进气流动对PFI汽油机燃油喷雾碰壁过程的影响

进气流动对进气道喷射式(PFI)汽油机燃油喷射过程有重要的影响,采用数值计算及台架试验的方法研究了进气流动对汽油喷雾碰壁过程的影响。研究表明:进气气流有助于燃油的空间雾化,减少以液态形式到达壁面的燃油;进气流动能够明显提高喷雾的贯穿性能,同时在进气流动方向上产生的偏转使附壁油膜的落点产生变化,使油膜的面积增大,有助于附壁油膜的蒸发;当机体温度较低时,进气流动对燃油蒸发的作用较为明显;当节气门开度较大时,由于温度较高,进气流动对发动机性能的改善效果不明显。

Influences of Intake Flow on Spray and Wall-film for Port Fuel Injection Gasoline Engine

The influences of intake flow on spray and wall-film were studied by using numerical simulation and test-bed experiment. Some results were received and they showed that the intake flow was useful for liquid fuel evaporation before impinged on the wall and could increases the spay penetration and deflect the spray in the direction of the intake flow. Meanwhile, the momentum of the spray droplets was strengthened and more small droplets could be received by the intake air flow which can enlarge the wall-film area and improve the evaporation of wall-film. If the engine body temperature was low, the effect of intake flow on engine performance was obvious while it had no difference under wide throttle open angle for high engine temperature.