不同喷孔夹角的直喷柴油机涡流室燃烧系统性能分析

摘要

In order to improve the particle spatial distribution, promote the mixing of oil and gas, and enhance airflow movement in a combustion chamber, a swirl chamber combustion system in direct injection diesel was investigated. The mixture formation and combustion progress in the combustion chamber were simulated, including different nozzle hole cone angles with 146°, 150° and 154°. The results showed that in view of the fuel/air equivalence ratio distribution, the uniformity of mixture on nozzle hole cone angle of 146°was better than others. The combustion swirl and anti-squish swirl have effect on temperature distribution in the combustion chamber. NO emission was lowest with nozzle hole cone angle of 154°, while soot emission was lowest with nozzle hole cone angle of 146°. The emission performance was better than others with nozzle hole cone angle of 150°.%为改善燃烧室内喷雾的空间分布,增强气流运动,促进油气混合,基于前期研究提出的新型直喷柴油机涡流室燃烧系统,对146°、150°、154°喷孔夹角的3种不同喷油嘴在燃烧室内的喷雾、混合气形成与燃烧过程进行了数值模拟.结果表明:从燃空当量比总体分布来看,采用146°喷孔夹角时混合气最均匀.燃烧涡流和逆挤流对速燃期的燃烧室内温度分布有较大的影响.154°喷孔夹角的NO排放量最低,而146°喷孔夹角的碳烟排放量最低.综合来看,150°喷孔夹角有较好的排放性能.