EGR对轻型柴油机超细颗粒排放的影响

发布时间：2019-07-30 16:04

【摘要】：基于1台匹配废气再循环(EGR)系统的轻型柴油机,在中低负荷下研究了EGR对发动机超细颗粒排放的影响。研究发现:各工况下,随EGR率的增大,颗粒排放中核模态颗粒数量浓度在各粒径下有所减少,核模态颗粒排放数量速率和质量速率有减少趋势,且在最大扭矩转速的低负荷工况更加明显;积聚态颗粒数量浓度在各粒径下都增加,积聚态颗粒排放数量和质量速率也都增加,且中负荷时更加明显,而积聚态颗粒数量浓度峰值粒径基本没有改变。随EGR率的增大,总的超细颗粒排放数量速率在最大扭矩转速的低负荷工况减小,而其他工况都明显增加。由于积聚态颗粒总质量浓度占超细颗粒总质量浓度比例达99%,所以超细颗粒排放质量速率也都增加,几何平均粒径也都明显增大。在低负荷较低EGR率和中负荷较大EGR率时,过高的喷油压力都将使超细颗粒排放数量速率增加。
[Abstract]:Based on a light diesel engine with matching exhaust gas recirculation (EGR) system, the effect of EGR on the emission of ultra-fine particles was studied under medium and low load. It is found that with the increase of EGR rate, the concentration of nuclear mode particles in particle emission decreases under each particle size, and the emission quantity rate and mass rate of nuclear mode particles decrease, and it is more obvious in the low load condition of maximum torque speed. The quantity concentration of accumulated particles increased under each particle size, and the emission quantity and mass rate of accumulated particles also increased, and it was more obvious at medium load, but the peak particle size of accumulated particles did not change. With the increase of EGR rate, the total emission rate of ultra-fine particles decreases at the low load condition of maximum torque speed, but increases obviously in other working conditions. Because the total mass concentration of accumulated particles accounts for 99% of the total mass concentration of superfine particles, the emission mass rate of superfine particles also increases, and the geometric average particle size increases obviously. When the EGR rate is low and the EGR rate is large at medium load, the emission rate of ultra-fine particles will be increased when the injection pressure is too high.
【作者单位】：同济大学;
【基金】：国家“863”高科技研究发展计划(2012AA111720)
【分类号】：TK421.5

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