Research On Numerical Simulation Of Commercial Diesel High Pressure Common Rail Fuel System

As the global energy crisis and environmental pollution are more and more serious,requirements on diesel engine power and emission performance continue to increase.Using the high pressure common rail fuel system is a key measure to improve the whole performance of the diesel engine.The common rail fuel system is widely recognized as the most advanced level of the diesel engine fuel injection system,which can significantly increase the power and fuel economy performance.Based on a type of heavy-duty diesel engine high pressure common rail fuel system,this paper analyzes the response characteristics and spray characteristics of the common rail fuel system through numerical simulation method.And at last,the orthogonal design method is carried out to optimize the key parameters of the injector according to the results.Firstly,this paper simplifies the system according to the actual demand and working principle of the common rail fuel system,and then establishes the corresponding mathematical model.Using the AMESim software to build the simulation model and demarcate the simulation with experimental data.The result shows that the model can more truly reflect the spray characteristics of the common rail fuel system,and can be used in common rail fuel system simulation research.Secondly,based on the established simulation model,the rail pressure?volume of control room?oil inlet/outlet pole diameter?control plunger diameter?needle valve sealing diameter?the needle valve spring preload effect on the response characteristics and spray characteristics of the fuel system are deeply studied.And then summarize the influences of the various parameters in order to find the ideal area of each parameter selection.Lastly,the key parameters of the injector are matched by using the orthogonal design method and the best optimization scheme of both the injector response characteristics and spray characteristics are obtained.The specific conclusions are as follows:when the control plunger diameter is 4.2mm,volume of control room is 0.02cm,needle valve spring preload is 79N,needle valve sealing diameter is 3.8mm,the injector response characteristics and spray characteristics are the best.After optimization of the injector,the overall response characteristics of the injector are improved by 32.24%,the spray characteristics are improved by 7.91%,closer to the target cycle injection quantity.This scheme improved the response characteristics and spray characteristics of high pressure common rail fuel system.