Common Rail Injector Simulation Calculation And Parameter Optimization

With the rise of the requirements of the emissions regulations, energy-saving andnoise of the diesel engine, engine electronic control becomes the main direction infuture development. As the core technology of diesel engine, breakthrough of the fuelsystem diesel is important to energy saving. Especially as widely recognized thehighest level of the diesel engine fuel injection technology, electronic controlhigh-pressure common rail fuel injection system can significantly increase the powerand fuel economy diesel engine.In this paper, the performance of the high-pressure common rail fuel injectionsystem developed by the China FAW Wuxi Fuel Injection Equipment ResearchInstitute is studied. I build the AMESim model of the fuel injector, find out the keystructure parameters, optimize the injector performance using Optimus, main researchcontents and conclusions are listed below:The mathematical model of the high-pressure common rail injector hydraulic andmechanical subsystems is derived, the AMESim simulation model is then established.Models are validated with the experimental data of fuel injection under different pulsewidth and rail pressure.Under low rail pressure, low pulse width or high rail pressure, high pulse width,research into the effects of inlet orifice effective flow area, outlet orifice effectiveflow area, the control chamber volume and needle valve spring pre-load force on thehigh-pressure common rail injector fuel injection rate, fuel injection quantity, controlchamber pressure, needle lift curve and nozzle volume pressure etc.. Under low railpressure and low pulse width, these structure parameters have a significant impact onfuel injection characteristics. Under high rail pressure and high pulse width, the inletorifice effective flow area and outlet orifice effective flow area have greater impact onfuel injection law, the control chamber volume and needle valve spring pre-load havelittle effects.The single injection rate is Single-objective optimized through optimization platform Optimus. Using orthogonal design and response surface analysis, effects ofvarious parameters and their interactions on the the fuel injection rate are researched.To meet the target injection rate, adaptive evolutionary genetic algorithm is then usedto optimize it.The injector needle rise/fall time is multi-objectively optimized. Usingorthogonal design and response surface analysis, effects of various parameters andtheir interactions on the injector needle rise/fall time are researched and Paretooptimal solution frontier is obtained. The optimization results show that, the rise timeof the needle valve is reduced by9.1%, the fall time of the needle valve is8.8%lowerand injector hydraulic response characteristics are improved.