[Influence of Noble Metal and Promoter Capacity in CDPF on Particulate Matter Emissions of Diesel Bus].

This study investigates the influence of noble metal capacity and promoter capacity in diesel oxidation catalysts (DOC) and catalyzed diesel particulate filters (CDPF) on particulate matter (PM) emissions. Four types of exhaust aftertreatments were applied to a diesel bus engine that meets the national Ⅲ emissions regulations. On-board tests were conducted respectively. PM emissions from the engine were strongly influenced by noble metal capacity in DOC and CDPF, especially at high speeds (the total number of particles increased by 70.8% when the noble metal capacity decreased by 5 g·ft-3 at 60 km·h-1). The higher the noble metal capacity was, the lower the PM emissions became, especially for PM in nuclei mode. The lanthanide material contributed to reducing PM emissions significantly. The content of precious metals could be reduced by 25% with proper lanthanide material, while the treatment effect of exhaust particles was guaranteed. In summary, aftertreatments are not sensitive to accelerating conditions, but the purification efficiency is obviously different under decontamination conditions.