用于汽油机燃烧优化的预测模型研究

Study on Prediction Model for Combustion Optimization of Gasoline Engine

试验中发现在工况和调整参数不变情况下,各个循环间的平均指示压力存在很大差异。利用Simulink分析了汽油机不同试验点2000个工作循环中平均最大指示压力对应瞬时放热过程。在其他参数都相同的条件下,点火提前角增大,瞬时放热开始点提前,且放热过程对称。在此基础上又利用Simulink建立了瞬时放热公式,并对气缸内压力进行预测建模,预测出的气缸压力与试验值吻合良好。

With the same conditions and adjusting parameters of gasoline engine, different cycles had so largely different mean indicated pressure. Then using the Simulink software, the corresponding instantaneous heat release process for mean maximum indicated pressure in 2 000 working cycles in different test points was analyzed, With other parameters unchanged, the ignition angle increased, the start point of heat release advanced and the process of heat release was symmetrical. Beside these, the formula of instantaneous heat release and the prediction model of in-cylinder pressure were built. Finally, the in-cylinder pressure was predicted with prediction model and its value was in accordance with test value.