DOC+DPF系统对柴油机污染物排放特性的影响OACSTPCD

Based on the diesel engine bench equipped with diesel oxidation catalyst(DOC)and diesel particulate filter(DPF),the flue gas analyzer of Testo 350XL and the engine exhaust particle size spectrometer of TSI EEPS 3090 were used to investigate NOxand particulate matter(PM)variation under different loads before and after the DOC and after the DPF.The results show that the NO 2 volume fraction of φ(NO2)is increased significantly after DOC when the load is greater than 50.0%.With the increasing of engine load,NO2 volume fraction in nitrogen oxides φ(NO2/NOx)of the raw diesel engine is decreased,while the φ(NO2)and φ(NO2/NOx)of the DOC and the DPF are decreased first with latter increasing.The raw diesel engine PM emission is depended on the operation conditions of the diesel engine.The PM removal rate of DOC is 15%-30%under different loads,and the PM removal rate of DOC under 50.0%load has the highest value of 26%.The PM removal rate of DPF is exceeded 90%.The nucleated particles volume fraction after DPF is increased,while aggregated particles volume fraction is decreased.