Abstract: There's still a significant gap between China and the western developed countries in the field of highpower and highspeed diesel engines, and as a core component, the fuel supply system directly determines the power output characteristics of diesel engines. EUP system used in a domestically produced highpower diesel engine was took as the research object in this article, EUP system model was established by using Hydsim software, the experimental data was comparedto verify the accuracy of the model, the influence of system structural parameters on fuel injection characteristics was studied, and the variation law of fuel injection characteristics with various parameters was obtained. The results show that increasing the pretightening force of the needle valve spring canmake the oil cutoff process more rapid and brittle.The larger the mass of the needle valve is, the more severe the gas leakage phenomenon is. Increasing the maximum lift of the needle valve can significantly improve the throttling effect, resulting in a 28.58% increase in fuel injection pressure. When the total flow area is fixed, a smaller number of orifices can improve the quality of spray. Increasing the orifice diameter of the injection hole can improve the throttling effect, reduce the injection pressure by 32.98%, increase the circulating injection volume by 19.51%, improve the head leakage of the needle valve, and improvethe spray quality.

Key words: electronic control unit pump, diesel engine, numerical simulation, structural parameter, fuel injection characteristics

摘要： 我国与西方发达国家在大功率高转速柴油机领域还有较大差距，燃料供给系统作为核心部件，直接决定柴油机的动力输出特性。为此，以一款国产大功率柴油机所使用的电控单体泵系统为研究对象，利用Hydsim软件建立该系统模型，对比试验数据验证模型的准确性，研究系统结构参数对喷油特性的影响，获得喷油特性随各参数的变化规律。结果表明：增大针阀弹簧预紧力会使断油过程更加迅速干脆；针阀质量越大，串气现象越严重；提高针阀最大升程能明显改善节流效应，喷油压力上升28.58%；总流通面积一定时，较少的喷孔数目会提高喷雾质量；增大喷孔直径能改善节流效应，喷油压力减小32.98%，循环喷油量增大19.51%，针阀头部泄漏得到改善，喷雾质量得到提升。

关键词: 电控单体泵, 柴油机, 数值仿真, 结构参数, 喷油特性