曲轴箱窜气对柴油机尾气微粒排放影响

Effect of Crankcase Blow-by on Particle Emission of Diesel Engine

针对一台2.0 L柴油机搭建了试验台架,通过控制曲轴箱窜气直接排入大气或是引入进气系统,采用尾气粒径谱仪对两种情况相应的尾气微粒数量浓度进行测量,分析比较试验结果来研究曲轴箱窜气对内燃机微粒排放的影响。结果表明:曲轴箱窜气引入进气主要影响柴油机尾气中核模态微粒及100 nm以下集聚态微粒的粒径数量浓度分布,主要表现在高峰峰值的增加和新峰值区域的形成。另一方面,曲轴箱窜气引入进气使柴油机各工况下尾气微粒总数量浓度增加,中、大窜气量工况微粒绝对数量增加明显,增幅分别为44.2%和38.5%。

By controlling the flow of crankcase blow-by to atmosphere or intake system, particle number concen- tration distribution was measured in the situations above in a 2.0 L diesel engine, to investigate the effect of crank- case blow-by on particle emission in different blow-by leakage conditions. The results show that taking crankcase blow-by into the intake system of diesel engine mainly affects the concentration distribution of nuclei model particle and accumulation mode particle below 100 nm. The maximum value of partical number concentration increases and new concentration peak area is developed. In addition, taking crankcase blow-by into the intake system leads to the increase in the total number concentration of diesel engine exhaust particle in all conditions. The increases of total number concentration in the conditions of middle and high blow-by leakage reach up to 44. 2% and 38.5% respec- tively.