DOC+CDPF对国III重型柴油货车实际道路排放的影响

Impacts of DOC+CDPF on real-world emissions from China III heavy-duty diesel trucks

利用便携式车载排放测试系统(PEMS)对2辆加装氧化催化转化器(DOC)和催化型柴油颗粒捕集器(CDPF)与否的国III重型柴油货车进行实际道路排放测试.结果表明,2辆改造重型柴油车的CO、THC、固态颗粒物粒数(SPN)和黑碳(BC)实际道路排放因子分别为(1.31±0.37)g/(kW·h)、(0.20±0.03)g/(kW·h)、(7.13×1010±5.27×1010)个/(kW·h)和(0.69±0.06)mg/(kW·h),相对于原始排放(拆除DOC+CDPF)分别降低52.48%、55.69%、99.91%和99.22%.从低速、中速到高速,CO和THC减排比例呈现上升趋势,然而运行工况对SPN和BC减排比例则无显著影响.加装DOC+CDPF会导致NO2在NOx中的占比升高,且从低速、中速到高速涨幅依次增大,但对NOx无明显减排效益,其排放因子为9.53~9.83g/(kW·h),远高于实验室排放限值.

On-road emission measurements of two typical China III heavy-duty diesel trucks with and without diesel oxidation catalytic converter(DOC)and catalyzed diesel particulate filter(CDPF),have been conducted by using a portable emission measurement system(PEMS).The results indicated that real-world emissions of CO,THC,solid particle number(SPN)and black carbon(BC)from the two retrofittedvehicleswere(1.31±0.37)g/(kW⋅h),(0.20±0.03)g/(kW⋅h),(7.13×1010±5.27×1010)particle/(kW⋅h)and(0.69±0.06)mg/(kW⋅h),respectively.Compared with the original emissions(i.e.,DOC+CDPF removed),these emissions were reduced by 52.48%,55.69%,99.91%and 99.22%,respectively.From low-speed,medium-speed to high-speed driving conditions,the reduction ratio of CO and THC showed an upward trend,butthere was no significant difference in the emission reduction of SPN and BC under various operating conditions.Retrofitting with DOC+CDPF had no significant reduction effect on NOx emissions,which were 9.53 to 9.83g/(kW⋅h),higher than the emission limit.However,the proportions of NO2 in NOx were increased,and the elevations got enhanced from low-speed,medium-speed to high-speed driving conditions.