直接起动过程缸内直喷汽油蒸发的影响规律研究  

Investigation of Direct-Injection Gasoline Spray Evaporation Characteristics in Direct-Start Process

作　　者：肖茂宇[1] 石磊[1] 邓康耀[1] 

机构地区：[1]上海交通大学动力机械与工程教育部重点试验室,上海200240

出　　处：《内燃机工程》2016年第2期12-18,共7页Chinese Internal Combustion Engine Engineering

基　　金：国家自然科学基金项目(51106098);国家"八六三"高技术研究发展计划项目(2012AA111702)

摘　　要：采用三维数值模拟并用定容喷射室试验验证的方式,对直喷汽油机起动首缸中喷油后油气混合及燃油的蒸发附壁情况进行研究。研究结果表明:直接起动缸喷油后燃油附壁的比例较大,点火前仍有部分液滴以液态形式存在于混合气当中;随着温度上升,混合气中的液态燃油比例逐渐减小并趋于0,附壁油膜的质量比率在温度低于140℃时明显减少,高于140℃后减幅趋于平缓。对比研究醇类汽油与汽油可以得到:醇类汽油喷射后的燃油蒸发较差,点火前燃油附壁比例过大,不适用于不使用起动电机辅助的直接起动方式。Direct-starting without any starting aid for direct-injection spark ignition （DISI） engine could improve engine fuel consumption and emissions, but it has high requirements for the quality of fuel and air mixture formation. In view of this, a 3-dimensional numerical simulation and experimental test by constant volume spray chamber were combined to investigate the spray evaporation and wall interaction in the first-injection cylinder by direct starting, The results show that the ratio of wall film mass to injected mass is very large, and there are many droplets remained liquid in the air before first ignition. With the increase of temperature, the ratio of liquid fuel mass in the air is reduced with a tendency to 0. Wall film mass ratio has been sharply decreased when temperature is blow 140 ℃, and then leveled off when temperature is above 140 ℃. Comparing alcohol fuels to gasoline shows that because of the higher mass of alcohol fuels injected than that of gasoline, wall film mass will be increaseed, so alcohol fuels are not suitable for the direct starting of DISI engine.

关 键 词：内燃机 直喷汽油机 直接起动 喷雾蒸发 燃油附壁 三维数值模拟 

分 类 号：TK411[动力工程及工程热物理—动力机械及工程]