Design And Disquisition On Numerical Analysis Of High-middle Speed Diesel Engine Fuel Injection System

The fuel injection system (FIS) is a very important part of a diesel engine, which affects the performance of power, economic and exhaust of an engine. It is must pay attention to the FIS when the new engine would to be designed, or an old one would to be redesigned.Now there are two types FIS to be used in the widely field. One is the system of Pump-Line-Orifice, which is used in the high power engines; the other is the Common-Rail FIS which is used in the low power engines. The thesis designs a new FIS which is used in a middle-high speed diesel engine, and gives the key structure dimensions of the design. Then the keys were analyzed by HYDSIM, the special software for FIS. The factors which influence the performance of the FIS were found, and the design was optimized.The thesis fingers out that the cam profile, the diameter of plunger, the effect shafting of plunger, the diameter of the high-pressure line, the lift of the needle and the total section area of the orifice are the keys for the performance of the FIS.The thesis fingers out that it is imprecise to decided the diameter of the high-pressure line using the experiential relation between the diameter of the plunger and that of high-pressure line. And the thesis suggests that the max pressure of the injection should be considered when the designer choice the diameter of the high-pressure line, especially for a high injection pressure system.