Research On Injection Performance And Multi-objective Optimization Of Large-flow Electronically Controlled Injector

As the cutting-edge technology of modern diesel engine fuel system,electronically controlled fuel system has the advantages of high injection pressure,precise control of injection timing,flexible and adjustable injection rule.Electronically controlled fuel injector is component with the highest technical requirements and the most significant effects in the electronically controlled fuel system.Its fuel injection performance directly affects the performance of the fuel system and it is the main breakthrough point to further improve the overall performance of the diesel engine.Therefore,this article takes the large-flow electronically controlled injector as the research object,and carries out the research of fuel injection performance and multi-objective optimization,aiming to lay the foundation and provide reference for the engineering research and development of electronically controlled injector.Firstly,the numerical model research of large flow electronically controlled fuel injector was carried out.The system composition and working principle of the large-flow electronically controlled fuel injector were described.The modular modeling method was used to construct a numerical simulation model.With the help of test data and simulation data,the accuracy of the model was verified on multiple indicators,which included such as fuel injection rate,fuel injection opening response,fuel injection duration and cycle injection fuel quantity,which showed that the numerical simulation model can accurately feedback the fuel injection performance of the large-flow electronically controlled fuel injector.Secondly,the research on the influencing factors of the fuel injection performance of the large flow electronically controlled injector was carried out.Defined the opening response and the closing response as response characteristic measurement index,the injection pressure fluctuation and the injection pressure drop as pressure characteristic measurement index,the cycle injection fuel quantity and the average fuel injection rate as cycle injection fuel quantity characteristic measurement index,revealing the change rule of response characteristics,pressure characteristics and cycle injection fuel quantity characteristics under the full working condition plane.And the variable parameter analysis method was used to obtain the influence law and mechanism of characteristic parameters on fuel injection performance.Among them,the characteristic parameters included the structural parameters of solenoid valve,control cavity,and needle valve.Thirdly,the quantitative research on the fuel injection performance of the large flow electronically controlled injector was carried out.Taking response characteristics,pressure characteristics and cycle fuel injection quantity characteristics as the goal,as the sensitivity of each characteristic parameter to each characteristic measurement index was different,the weight analysis method was used to obtain the influence degree of its characteristic parameters under different working conditions,and further extract the key parameters of the impact of each characteristic measurement index.At the same time,combined with the experimental design and correlation analysis method,the influence of the interaction of characteristic parameters on the measurement indicators of fuel injection performance was revealed.Finally,the multi-objective optimization research of large flow electronically controlled injector is carried out.A multi-objective optimization method for electronically controlled injectors based on an approximate model was proposed.With the help of experimental design and approximate model,the synergy of different characteristic targets and the interaction of different characteristic parameters were fully considered,and a multi-objective optimization method for large-flow electronically controlled injectors was constructed.The model was based on the optimization algorithm to solve the optimization target Pareto solution set,and the minimum distance screening method was used to obtain the best solution.Under the premise of ensuring no loss of the average fuel injection rate,under the typical working conditions of 180 MPa rail pressure and 1.5 ms control pulse width,the total response time has increased by 10.04%,and the injection pressure fluctuation has been reduced by 12.01%,the fuel injection pressure drop has been reduced by 9.77%,and the optimization effect was excellent in all working conditions.The multi-parameter optimization matching of the multi-objective coordination of the large-flow electronically controlled fuel injector was realized.