Pressure Drop and Soot Accumulation Characteristics through Diesel Particulate Filters Considering Various Soot and Ash Distribution Types 2017-01-0959

Although diesel engines offer higher thermal efficiency and lower fuel consumption, larger amounts of Particulate Matters (PM) are emitted in comparison with gasoline engines. The Diesel Particulate Filters (DPF) have proved one of the most promising technologies due to the “particle number” emissions regulations. In this study, the Computational Fluid Dynamics (CFD) multi-channel model of DPF was built properly by utilizing AVL-Fire software code to evaluate the pressure drop and soot accumulation characteristics of DPF. The main objective of this paper was to investigate the effects of soot (capacity and deposit forms) and ash (capacity and distribution factors) interaction on DPF pressure drop and soot accumulation, as well as the effects of DPF boundary conditions (inlet mass flow rate and inlet temperature) on pressure drop. The Asymmetric Cell Technology (ACT) of DPF was proposed to evaluate the effects of the inlet to outlet width ratios on pressure drops and soot regeneration, and optimize the filter structure in practical applications. The results showed that the pressure drop sensitivity increases with the increased DPF inlet mass flow, inlet temperature, soot loading and ash accumulation, and the pressure drop change is not linear relationship with inlet temperature. The PM distribution is non-uniform and both ends of DPF contain a higher soot loading than the middle part. The “Linear decrease” soot pattern has a lower pressure loss and faster regeneration rate. The ash deposited on inlet channel walls results in larger pressure drops and prevents soot accumulation in the pores dramatically compared with ash deposited as plug. The ACT design filter can reduce the pressure drop, improve the soot accumulation performance, and accelerate regeneration rate at high soot and ash loads.