Study On The Performance Of Large Flow And High Speed Fuel System Of Diesel Engine

The high speed high pressure common rail system and the large flow high pressure common rail system of diesel engine need to greatly increase their fuel supply under constant maximum engine speed,which requires their fuel supply pumps to achieve high efficiency under wide range and large flow condition,and requires their injectors to further improve the fuel injection pressure and performance.Large flow high pressure common rail system also requires reducing fuel pressure fluctuation of common rail pipes.The fuel supply pumps of the two fuel systems adopt fuel metering mode,and the injectors adopt non-static-leakage structure.In order to improve the performance of the common rail systems and the components,study the influence of parameters on the performance,realize the optimal matching of parameters and solve the problems in the process of product development,the working principle of the large flow and high speed common rail systems were analyzed and the simulation model of hydraulic components such as the large flow pump,the high speed pump,the non-static-leakage injector and the large flow high pressure common rail system were built whoes prediction accuracy was verified by experiments.Results of experiments and simulation showed that the design of fuel supply pumps and injectors in the two fuel systems meeted the requirements.The influence of the fuel supply pump parameters on the volumetric efficiency loss and the three-dimensional flow field of the metering valve of the large flow pump,including pressure and velocity distribution,were simulated and analyzed.The fuel pressure and velocity distribution at the nozzle of the non-static-leakage injector was studied by simulation.The sensitivity factors of the fuel injection quantity were analyzed through Monte Carlo method,which helped optimize the injectors.The structural parameters of the common rail pipes in the large flow high pressure common rail system were optimized by simulation,which reduced the rail pressure fluctuation below the target value.