燃油喷射对柴油机燃烧及排放的影响

Research on the impact of fuel injection on diesel engine combustion and emissions

针对4190柴油机燃油系统电控化改造项目,应用AVL_FIRE三维CFD软件平台,建立该机缸内高压循环仿真模型,通过台架试验获得缸压曲线验证仿真计算的正确性。借助模型研究燃油喷射系统参数对燃烧、NOX和碳烟颗粒生成等的影响。结果表明:随着喷孔锥角的增大,缸内最大温度与压力逐渐增大,采用小喷孔锥角时,NOx排放浓度低,但碳烟排放浓度较高;喷油器喷孔直径增大,缸内压力与温度逐渐增大,采用0.30 mm喷孔直径时,NOx和碳烟的排放浓度均较低;喷油提前角增加导致缸内温度增大,NOx排放浓度增加,碳烟排放浓度降低。

For the project of realizing the electronic control of fuel injection system for 4190 marine diesel engine, the simulation model for diesel combustion was set up on the software platform of AVL_FIRE which was verified by experimental data, by using the stimulation model, this paper has analyzed the effects on the NOx and SOOT emission concentrations of the parameters of the fuel injection system. The results show that： along with nozzle hole cone angle increases, the maximum temperature and pressure in cylinder increase, A small cone angle nozzle, NOx emission concentration is low, but higher concentrations of soot emissions; injector nozzle diameter increases, the cylinder pressure and temperature increases, the use of 0. 30 mm diameter orifice, NOx and carbon smoke emission concentrations were lower.