DPF主动再生过程颗粒排放特性试验

通过柴油发动机台架,采用后喷助燃的再生方式研究了主动再生过程中柴油机颗粒捕集器(DPF)出口的颗粒排放特性.结果表明:在主动再生期间,DPF出口颗粒浓度可增加2~3个数量级;在升温过程和再生过程,出口颗粒物数量浓度和粒径分布会因为碳载量和再生温度的共同作用而表现出差异;升温过程中,10 nm左右核模态颗粒物的排放主要由来流中颗粒物的穿透引起;再生过程中,10 nm左右核模态颗粒物的排放主要由碳烟颗粒层氧化反应生成的二次颗粒逃逸引起;整个再生期间,100 nm左右的积聚态颗粒物的排放主要由DPF载体内碳烟颗粒的逃逸引起.

Experiment on Particulate Emissions During Diesel Particulate Filter Active Regeneration

The characteristics of particulate emissions downstream of the diesel particulate filter(DPF)during active regeneration process were investigated on a diesel engine with post injection regeneration mode.The experimental results show that the particle concentration downstream of the DPF is increased by 2-3 orders of magnitude during the active regeneration process.The concentration and size distribution of particulates show obvious difference due to the interaction between soot loading and regeneration temperature during the DPF heating up and regeneration.In the process of heating up,the particulate emissions of nuclei mode with a size of about 10 nm are mainly caused by the penetration of particulates from incoming streams.In the process of regeneration,the particulate emissions of nuclei mode with the size of about 10 nm are mainly caused by the secondary particles escaping from the oxidation reaction of soot particles.During the whole regeneration period including the process of heating up and regeneration,the particulate emissions of accumulated mode with a size of about 100 nm are mainly caused by escapes of the soot layer inside the DPF carrier.