天然气直喷发动机当量比与稀薄燃烧对比研究

Comparative Research of Stoichiometric Combustion and Lean-Burn for Direct-Injection Natural Gas Engine

针对一台自然吸气四缸天然气缸内直喷发动机,建立了发动机仿真模型,通过台架试验数据对模型进行了验证。开展了均质当量比燃烧和稀薄燃烧两种方案的整机动力性、热负荷和经济性对比研究。结果表明:稀薄燃烧时动力性下降明显,当量比燃烧时热负荷较高,空燃比稍大于当量比时经济性最好。

Based on a 4-cylinder naturally aspirated direct-injection natural gas engine,the numerical simulation model was built up,and the model was validated by the data from engine test bench.The characteristics of engine power,thermal load and economy were compared between stoichiometric combustion and lean burn.The results show that the engine power at lean burn was much worse compared with stoichiometric combustion,and heat load at stoichiometric ratio combustion was higher.When air fuel ratio was a little bigger than stoichiometric ratio,the engine fuel economy was the best.