In this paper, it was researched the degradation characteristics of catalytic performance of three kinds of DPFs (C1, C2 and C3, with precious metal concentrations being 15, 25 and 35 g/ft3 respectively) after diesel truck aging. It is found out that the crystallinity of three kinds of DPF samples (Used) in full vehicle aging was higher than that of fresh samples (Fresh) and aged samples (Aged) in the laboratory. Compared with Fresh samples, the concentration of Pt atom in precious metal on the surface of Aged and Used samples tends to decrease in most cases. Activities to CO and C3H8 of Aged and Used samples of three kinds of DPFs had all been degraded, and activity degradation showed a substantial correlation with concentration reduction rate of precious metal on the carrier surface. NO_2 productivity of Used samples all rose. Crystallinity of DPF samples after full vehicle aging in Inlet, Middle and Outlet areas successively increased. The reduction rate of Pt atom concentration of Inlet samples was higher, followed by that of Outlet layer samples, and that of Middle layer samples was lower. Activities to CO, C3H8 and NO_2 of Inlet samples were relatively low, yet the catalytic activity of Middle samples was relatively high. Activity differences were resulted from the differences of thermal degradation due to different thermal loads during aging.
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