Stability Study On Dynamic Injection Process Of Electronically Controlled Double-valve Fuel Injection System

In order to satisfy the increasingly stringent emission standards and improve the fuel economy,high pressure fuel injection technology has been widely concerned as a critical technology for diesel engine energy saving and emission reduction.Electronically controlled double-valve fuel injection system control the fuel supply and injection process individually by two high-speed solenoid valves.It can achieve very fast dynamic response and flexible adjustable fuel injection rate.However,in the condition of high pressure transient flow,it is very difficult to control the stability in the dynamic injection process of the system.Injection stability is the prerequisite for fuel injection system to match diesel engines,therefore,there is great significance to study on the stability of dynamic injection process.According to the working principle of electronically controlled double-valve fuel injection system,the simulation model of the system is established in the AMESim environment,the simulation model was verified by contrast between the experimental data and the simulation data,the result shows that the simulation model can be used to study on the injection characteristics of electronically controlled double-valve fuel injection system.On this basis,multi cycle fuel injection quantity stability of the system and its influence factor are studied,and the change of the system state matrices ranks is also analyzed by using the linear analysis methods.The stability change of the system in dynamic fuel injection process is studied based on the eigenvalues of the system state matrices.The results illustrate that the pulsating fuel supply of low pressure fuel supply system and pressure wave reflection and superposition in the high pressure pipe are the main reasons of the instability in dynamic fuel injection process,the multi cycle fuel injection stability was significantly affected by the cam profile velocity,plunger diameter,fuel supply pressure,diameter and length of the high pressure pipe,the action of spill control valve,needle control valve and needle valve make the rank of system state matrix change,causing the change of dynamic injection stability.High speed solenoid valve action process causes the system dynamic injection stability changing.According to the response time differences of the spill control valve and the needle control valve under different working conditions,the influence of control parameters to the spill control valve and the needle control valve response time under single injection and twice injection working conditions is studied,concrete rules about the influence of controlparameters to the spill control valve and the needle control valve response time under different working modes and speed are obtained.