设计、开发了50 MPa高压汽油直喷喷油器，在定容弹上研究了喷油器喷雾特性随喷射压力的变化关系，并在一台均质混合的缸内直喷光学单缸机上，通过燃烧分析和高速摄影等技术手段，研究了50 MPa高压汽油直喷技术对燃烧过程和排放的影响。结果表明：相较于当前主流的35 MPa缸内汽油直喷系统，将喷射压力提升至50 MPa仍能进一步降低喷雾粒径，改善油气混合过程，特别是在中高负荷区域能较大幅度降低未燃碳氢化合物及颗粒物排放，具有一定的潜在应用价值。

A high pressure direct injection gasoline injector with 50 MPa was designed and developed. The relationship between the spray characteristics of injector and the injection pressure was then studied on a constant volume bomb. The effects of 50 MPa high pressure and direct injection technology on the combustion process and emission were further studied on a single-cylinder optical engine of homogeneous charge and direct injection by using combustion analysis and high-speed photography. The results show that increasing the injection pressure to 50 MPa can still decrease the spray particle size and improve the fuel and air mixing process compared with the current 35 MPa in-cylinder gasoline direct injection system. It can greatly reduce the emissions of unburned hydrocarbons and particulate matter especially in the medium and high loads, which shows certain potential application value.