S195柴油机二次喷油的改型设计

A New Design of S195 Diesel Engine's Combustion System Based on Two-Step Injection

S195柴油机是在用农用机械,尤其是小四轮拖拉机和农用机械的主要动力,在不改变柴油机燃烧室内部结构和喷油器参数的情况下,对喷油泵凸轮进行改型设计,在原来单峰切线型喷油泵凸轮的基础上,相隔一定的曲轴转角,增加一个单峰,改进成为双峰凸轮,从而实现柴油机在进气冲程的时候提前预喷一定量的燃油,形成良好的燃油混合气,然后在接近压缩终了的时候主喷一定量的燃油,提高燃油和空气混合质量,从而使柴油机的燃烧性能和尾气排放得到改善。

The S195 diesel engine is a main power set for agricultural machines in use, especially for small fourwheeled tractors,and then a new design for the cam of fuel-injection pump without any modification to engin＇ s combustion chamber structure and injector parameters is carried out. On the basis of former cam with one peak tangent, the design adds another peak at an interval of some crankshaft angles, making it become a two-peak cam. By using the new cam, the diesel engine can inject fuel in advance at the stoke of air-intake, thus forming better fuel mixture, and near to the end of compression stroke, it injects some more diesel fuel as for improving the mixture quality of fuel and air. The performance and emissions of the diesel engine may obtain great improvement by them.