Analysis And Test Verification Of Leakage In High Pressure Fuel Injection System

The performance of the static seal in the couples of the injector in high pressure common rail system has an important influence on fuel injection law,which has a direct impact on diesel engine performance,fuel economy and emissions.With the continuous tightening of emission regulations,the pressure of fuel injection system is getting higher and higher,static sealing problems are more prominent.At present,the study of static seal is not enough in depth,this paper carried out some exploratory work in this area.The physical property parameter of fuel and the deformation have serious influence on the static seal in the couples,which influence each other as well.To accurately describe the influence,this article first applys the mathematical modeling to solve this problem,the influence of the heat loss and the gravity have been ignore.Using Fluent software to analyze ring gap flow grid independence,conclude the general simulation specification for such problems.Use Matlab software for solving the mathematic model of ring crack,compare the calculated results with Fluent software,and then mathematical model is checked.Finally analyze the leakage rule of the initial state of the fuel and the structure parameters of the three couples with the verified model,and conclude that the influence of different parameters and the relation of primary and secondary,provide a reference for engineering design.Due to the control valve and needle valve leakage is quite small,the existing test methods can't measure the real leakage,and fluorescence is often used for quantitative analysis of the trace elements,based on this carry on fluorescence measuring fuel leakage test.First by weighing method and the fluorescence respectively to measure the leak of the plunger couples,then compare with the results of the two,verify the fluorescent method has pretty accuracy.Carry on the preliminary feasibility analysis on the control valve and needle valve,conclude that the fluorescence method can satisfy the test requirement.Comparison of test results and simulation results show the simulation model has good accuracy,analyze the differences and conclude some suggestions for simulation program modification and test program improvement.