小型非道路柴油机低排放燃油喷射系统仿真与优化设计

利用HYDISM模拟软件建立了某小型非道路柴油机燃油系统的仿真计算模型,用实测高压油管压力验证了模型的精度,研究了喷油泵凸轮型线与柱塞直径、高压油管内径及喷油器类型与参数等几个重要因素对燃油系统液力过程性能影响,并确定燃油系统优化匹配改进方案。对比试验证明:优化方案提高了燃油系统燃油喷射压力,高压油管泵端压力增大了10.2MPa,嘴端压力增大了16.8MPa,分别提高了25.4%和33.6%,喷油速率提高了20%,喷油持续期缩短了22%,从而改善了燃油的雾化性能与燃烧过程,装机后排放性能得到了明显改善,排放指标满足非道路柴油机国Ⅱ排放限值要求,且具有较高裕度。

Simulation and Optimal Design of Fuel Injection System of Small Non-Road Diesel Engine for Low-Emission

A fuel system calculation model was made basically on a small non-road diesel engine using the HYDISM software that was verified by the measured pressure of the high-pressure fuel tube.The effects of several important factors such as the cam profile and the plunger diameter of the fuel injection pump,the diameter of high-pressure fuel pipe and fuel injector types on fuel system hydraulic properties were studied.The fuel system optimization plan was determined.The comparison tests showed that the pressure of high-pressure fuel tube of optimal scheme increased 10.2 MPa at the side of pump and 16.8 MPa at the side of injector,respectively,improved 25.4% and 33.6%.The injection rate increased by 20%,the fuel-spraying duration was shortened by 22% compared with the original scheme.The fuel atomization performance and combustion process were improved.The emission performance with optimal scheme obviously improved which meets China Ⅱ Non-road Diesel Engine Emission Limit and has a large margin.