With the continuous improvement of environmental awareness, we continue to raise the emission standards of vehicles. Under such a trend, the China VI heavy-duty vehicle standard has officially landed. The formulation of this standard refers to the emission regulations of heavy vehicles in Europe Ⅵ. Optimized and deepened to achieve a reduction in NOx and PM emissions. At the same time, by controlling emissions in actual use, transparency of pollutant emissions also contributes to environmental supervision. In terms of emission limits, according to the mature emission control technology in China, the sixth stage of heavy vehicle pollutant emission goal is to reduce nitrogen oxides NOx and PM by more than 60%. At the same time, the particulate matter bulk (PN) limit should also be reduced by about 33%. With the upgrade of China VI emissions, it is well known that the after-treatment of China VI becomes more complicated. In addition to the SCR system of China V, there are more DOC, DP...