试验研究表明,在柴油机首着火循环前引入EGR可以改善柴油机首着火循环的冷起动性能。在试验研究的基础上,进行了化学动力学计算,进一步研究了EGR对起动燃烧的影响。计算发现着火循环前排气成分中的完全燃烧产物少,而未燃燃油和中间氧化产物的含量大,因此改善了燃烧。通过对不同EGR率和不同燃空当量比下,混合气在定容状态下的滞燃期进行分析,得到了混合气着火性能随着EGR率的变化规律。%It has been investigated experimentally that introducing some amount of exhaust gas to the diesel engine before the first ignition cycle can help to improve the combustion performance. Based on ex perimental research, chemical kinetics simulation was taken to investigate the effect of EGR on the com bustion performance of cold starting periods. The simulation results show that before the ignition cycle, the complete combustion products in exhaust gas is little, the content of residual fuel and intermediate ox idation products is big, therefore improving the combustion. For constant volume combustion, ignition de lay of mixed gas under different EGR ratios and different fuel/air ratios was calculated and analyzed, and the changing rule of ignition characteristics of mixed gas relating to EGR rate was obtained.
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