Experimental investigation on the variation characteristics of soot layer thickness and pressure drop during DPF/CDPF active regeneration

Abstract

The evolutionary mechanism of soot layer has a significant impact on Diesel Particulate Filter (DPF) regeneration process, which gains more interest due to environmental related requirements. In this study, a visualized single-channel filter deposition/regeneration test bench is re-designed to investigate the relation between soot layer thickness and pressure drop. Various operating conditions corresponding DPF and catalyzed DPF (CDPF) are tested and show good agreement. The results indicate that there are three stages among the regeneration process for samples. The decrease rate of the second pressure drop does not change significantly when the deposition thickness of the soot layer on the CDPF within 72–132 μm. Meanwhile, the CDPF is more sensitive than DPF responded to the filtration velocity. Besides, the decrease rate of thickness of CDPF (0.9 μm/min) is much higher than the DPF (0.39 μm/min) in the first stage, and soot layer of CDPF has a sharp drop in thickness. Overall, it is concluded that the oxidation process on bare DPF soot layer is ″Top TO Bottom″, while CDPF is ″Top AND Bottom″.