Research And Application Of Influence To The Performance Of Engine Cylinder Head And Valves Manufacturing Precision

Under the background of the Engine 2 microns project that Shanghai Jiao Tong University cooperate with SGMW,vehicle sales is increasing annually,vehicle fuel consumption regulations reduced annually,we need to constantly improve the manufacturing precision and consistency of the engine.As foreign and domestic research engine performance from the effects of the crank and cylinder-block is more and more perfect,honing technology on cylinder bore is increasingly perfect,reduction of engine friction is more and more difficult,in this environment,we must further analysis engine systems and other institutions influence on engine performance.So this article to valve system as the research focus,from valve system friction loss,the impact on the compression ratio,as well as the influence of combustion chamber sealing,valves manufacturing precision on engine performance are analyzed in detail.And in this study obtained the following results:1,the compression ratio calculation,the traditional calculation based on the design of the combustion chamber volume,ignoring the combustion chamber volume measurement,the influence of valve head,and through calculation analysis,this paper found that the influence of valve head is very big still,considering and not considering will enable compression ratio to expand the range of 24.19%.So on the one hand,compression ratio calculation after the proposal must consider the manufacturing precision of the part,in order to avoid calculating the compression ratio and actual difference fluctuations too big problem;On the other hand,advice on the cylinder combustion chamber volume measurement,need to be further in-depth study.2,the use of girth formula of flow,simple and easy to calculate the valve leakage.Although the calculation USES a simple model calculation,but for the valve leakage value provides a simple and feasible method to calculate the,set for leakage of the valve leak detection equipment provides a basic data,can be great convenience after commissioning of the equipment.