The Structural Simulation Analysis And Parameter Optimization Of Electronic Controlled Injector

The global energy crisis and increasingly serious pollution of the environment have endangered human’s survival environment. As the increasingly request to auto emission regulation and fuel economy of internal combustion engine raised, the countries in the world have made much more adjustments and control to them. High pressure common rail electric control system of fuel injection can effectively reduce fuel consumption and emissions of diesel engine, and significantly improve its dynamic performance. As key components in high pressure common rail fuel injection system, the electronic controlled injector has a direct control of the injection process of the high pressure fuel injecting into the combustion chamber. It ensures the normal and orderly work of diesel engine. The mixture formation and combustion in the cylinder can be directly affected by the spray characteristics of electronic controlled injector, which so as to affect the working characteristic and exhaust emission characteristics of diesel engine. And the selection of the key structure parameters of the electronic controlled injector has important influence on the response characteristic of the injector, spray quality, fuel injection law, and the mixture formation and combustion.In order to optimize the spray characteristics of electronic-controlled injector, the simulation of electronic-controlled injector was established. The simulation studied the effect of various structure parameters on the performance of the system, and obtained reasonable structural design parameters. The optimized structural parameters promote the fuel injection performance of electronic-controlled injector. Simulation calculation and analysis can not only save labor resources and social resources, but also shortening the period of R&D (research and development).Firstly the massive literature material was consulted, and full analysis was made to discuss the structural characteristics and working principle of electronic-controlled injector. Then its simplified physical model was established, and the calculation assumption was proposed on the basis of this physical model. And then a math model of electronic-controlled injector was built, which can be divided into three sub models:cubage cavity, pipes and valves. All kinds of related fluid mechanics equations were also set up. The simulation model of electronic-controlled injector was set up on the platform of AMESim which was hydraulic simulation software. Basing on this model, the structure parameters of injector was analyzed one by one, screening seven key structure parameters which affect the spray characteristics of injector biggest. The seven key structure parameters are:the control piston diameter, the flow coefficient of flue outlet, the diameter of the needle, the diameter of fuel inlet, the diameter of flue outlet, the flow coefficient of flue inlet, the flow coefficient of spray orifice.The optimization analysis of seven parameters was made through orthogonal experiment design method. Then ascertained the primary and secondary level of seven parameters impact on the spray characteristics of injector, and choose the optimal combination through the analysis result. Putting the optimal combination into the AMESim simulation model, and then compare the simulation result with the result before optimization. The conclusion was that the dynamic response characteristic of electronic-controlled injector had been greatly improved, and its fuel injection performance was also improved substantially, so a more ideal fuel injection law can be implemented.