[Effects of DOC+CDPF on Emission Characteristics of Heavy-duty Diesel Vehicle].

Based on the revolving drum test bench, an experimental study was conducted in heavy-duty diesel vehicle at China Stage Ⅲ with and without DOC+CDPF to investigate the effects of DOC+CDPF on the gaseous and particle emission characteristics under C-WTVC driving cycle. The results showed that from city circulation conditions to high way circulation conditions to high-speed circulation conditions, the CO, THC, CO and PM emission factors of the test vehicle without DOC+CDPF decreased while NO and PN emission factors increased, the particle number concentration showed two peaks versus the size of the particles and accumulated particles predominated. After the test vehicle was equipped with DOC+CDPF, the emissions factors decreased and the faster the circulation speed, the greater the decreasing amplitudes of the emissions factors. Throughout the C-WTVC, the decreasing amplitudes of CO, THC, CO, and NO emission factors were 70.36%, 72.73%, 17.00% and 7.76%, the PM and PN emission factors decreased by 93.77% and 98.91% respectively. The particle number concentration still had two peaks versus the size of the particles and the nuclear mode particles predominated. Besides, the size of the accumulated particles peak diminished.