Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to e...Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number （PN） emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter （PM） and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.展开更多
采用高硫柴油、国Ⅲ、国Ⅳ和国Ⅴ4种不同硫含量的基准燃油,在发动机台架上进行了加装DOC+POC后处理装置的国Ⅳ柴油机的ESC 13工况测试,并用AVL AMA i60气体分析仪对CO,HC,NOx和PM排放进行测量。研究了不同基准燃油对加装DOC+POC后处理...采用高硫柴油、国Ⅲ、国Ⅳ和国Ⅴ4种不同硫含量的基准燃油,在发动机台架上进行了加装DOC+POC后处理装置的国Ⅳ柴油机的ESC 13工况测试,并用AVL AMA i60气体分析仪对CO,HC,NOx和PM排放进行测量。研究了不同基准燃油对加装DOC+POC后处理装置的国Ⅳ柴油机的排放影响,并与原机作了对比。研究结果表明,CO和HC的转化效率与燃油硫含量有很好的相关性,DOC+POC后处理可有效减小CO和HC的排放,稳态循环下国Ⅴ柴油CO和HC的平均转化效率分别为90.6%和86.6%,且随着燃油中含硫量的降低而增大,特别是在高转速大负荷工况。受燃油硫含量影响,DOC+POC后处理装置对高硫柴油、国Ⅲ、国Ⅳ3种燃油的PM排放降低不起作用,反而会使PM排放增加,然而对国Ⅴ柴油的PM净化率可达81.8%。展开更多
The effects of a diesel oxidation catalytic （DOC） converter on diesel engine emissions were investigated on a diesel bench at various loads for two steady-state speeds using diesel fuel and B20. The DOC was very eff...The effects of a diesel oxidation catalytic （DOC） converter on diesel engine emissions were investigated on a diesel bench at various loads for two steady-state speeds using diesel fuel and B20. The DOC was very effective in hydrocarbon （HC） and CO oxidation. Approximately 90%-95% reduction in CO and 36%-70% reduction in HC were realized using the DOC. Special attention was focused on the effects of the DOC on elemental carbon （EC） and organic carbon （OC） fractions in fine particles （PM2.5） emitted from the diesel engine. The carbonaceous compositions of PM2.5 were analyzed by the method of thermal/optical reflectance （TOR）. The results showed that total carbon （TC）, OC and EC emissions for PM2.5 from diesel fuel were generally reduced by the DOC. For diesel fuel, TC emissions decreased 22%-32% after the DOC depending on operating modes. The decrease in TC was attributed to 35%-97% decrease in OC and 3%-65% decrease in EC emissions. At low load, a significant increase in the OC/EC ratio of PMz.5 was observed after the DOC. The effect of the DOC on the carbonaceous compositions in PM2.5 from B20 showed different trends compared to diesel fuel. At low load, a slight increase in EC emissions and a significant decrease in OC/EC ratio of PM2.5 after DOC were observed for B20.展开更多
基金supported by the National Natural Science Foundation of China (No. 50876013)
文摘Two continuously regenerating diesel particulate filter （CRDPF） with different configurations and one particles oxidation catalyst （POC） were employed to perform experiments in a controlled laboratory setting to evaluate their effects on NO2, smoke and particle number emissions. The results showed that the application of the after-treatments increased the emission ratios of NO2/NOx significantly. The results of smoke emissions and particle number （PN） emissions indicated that both CRDPFs had sufficient capacity to remove more than 90% of total particulate matter （PM） and more than 97% of solid particles. However, the POC was able to remove the organic components of total PM, and only partially to remove the carbonaceous particles with size less than 30 nm. The negligible effects of POC on larger particles were observed due to its honeycomb structure leads to an inadequate residence time to oxidize the solid particles or trap them. The particles removal efficiencies of CRDPFs had high degree of correlations with the emission ratio of NO2/NOx. The PN emission results from two CRDPFs indicated that more NO2 generating in diesel oxidation catalyst section could obtain the higher removal efficiency of solid particles. However this also increased the risk of NO2 exposure in atmosphere.
文摘采用高硫柴油、国Ⅲ、国Ⅳ和国Ⅴ4种不同硫含量的基准燃油,在发动机台架上进行了加装DOC+POC后处理装置的国Ⅳ柴油机的ESC 13工况测试,并用AVL AMA i60气体分析仪对CO,HC,NOx和PM排放进行测量。研究了不同基准燃油对加装DOC+POC后处理装置的国Ⅳ柴油机的排放影响,并与原机作了对比。研究结果表明,CO和HC的转化效率与燃油硫含量有很好的相关性,DOC+POC后处理可有效减小CO和HC的排放,稳态循环下国Ⅴ柴油CO和HC的平均转化效率分别为90.6%和86.6%,且随着燃油中含硫量的降低而增大,特别是在高转速大负荷工况。受燃油硫含量影响,DOC+POC后处理装置对高硫柴油、国Ⅲ、国Ⅳ3种燃油的PM排放降低不起作用,反而会使PM排放增加,然而对国Ⅴ柴油的PM净化率可达81.8%。
基金This work was financially supported by the National Science Fund for Distinguished Young Scholars of China （No. 20625722） and the National Natural Science Foundation of China （Grant No. 20807025）. We would also like to thank Prof. Yunshan Ge from Beijing Institute of Technology for the significant in-kind support on the engine test and thank Mr. Charles N. Freed for useful comments on this work.
文摘The effects of a diesel oxidation catalytic （DOC） converter on diesel engine emissions were investigated on a diesel bench at various loads for two steady-state speeds using diesel fuel and B20. The DOC was very effective in hydrocarbon （HC） and CO oxidation. Approximately 90%-95% reduction in CO and 36%-70% reduction in HC were realized using the DOC. Special attention was focused on the effects of the DOC on elemental carbon （EC） and organic carbon （OC） fractions in fine particles （PM2.5） emitted from the diesel engine. The carbonaceous compositions of PM2.5 were analyzed by the method of thermal/optical reflectance （TOR）. The results showed that total carbon （TC）, OC and EC emissions for PM2.5 from diesel fuel were generally reduced by the DOC. For diesel fuel, TC emissions decreased 22%-32% after the DOC depending on operating modes. The decrease in TC was attributed to 35%-97% decrease in OC and 3%-65% decrease in EC emissions. At low load, a significant increase in the OC/EC ratio of PMz.5 was observed after the DOC. The effect of the DOC on the carbonaceous compositions in PM2.5 from B20 showed different trends compared to diesel fuel. At low load, a slight increase in EC emissions and a significant decrease in OC/EC ratio of PM2.5 after DOC were observed for B20.
