Simulation Research On Diesel High-pressure Common-rail Fuel Injection System

High-pressure common rail system with electronic fuel injection is a developing tendency of fuel injection technology in light-duty vehicle diesel engine, which is acknowledged as an optimal fuel injection system at present. It is a mechanical electric and hydraulic pressure system which affects directly the performance of diesel engine. The aim of simulation is to study effects of its structural parameter and control parameter, put forward reasonable design parameter of the system, which are helpful to give some gist for demarcating and matching. It can save a lot of labors, material and funds .Meanwhile it gives an effective method to developing and researching.In this paper, with the combination of fluid mechanics and electromagnetic theory, the mathematical model of a high-pressure common-rail system is established according to the hydraulic characteristics, based on structure characteristic analysis of the ECD-U2 system. It is convenient to establish a high-pressure fuel pump subsystem by modular design methods, including the injection pump plunger lift and plunger cavity subsystem, and common-rail pipe subsystem. The electromagnetic valve subsystem includes circuit, magnetism and mechanics subsystems, and injector hydraulic pressure subsystem includes liquid flows and needle lift subsystem. According to features of the ECD-U2 system, the four subsystems will be integrated as high-pressure common-rail system simulation program. Then the high-pressure common rail electronic fuel injection system is simulated. The influence factors of fuel injection system characteristic are analyzed, including the structural parameters of high pressure pumps, the oil outlet valve, injector and high-pressure common-rail pipe. The quantify analysis is made on electromagnetic valve the starting and operating characteristics. Some conclusions give potent support to the design and matching of high-pressure common-rail fuel system.