Experimental study of hexagonal and square diesel particulate filters under controlled and uncontrolled catalyzed regeneration

Although diesel engines have high thermal efficiency, large amounts of PM (particulate matter) including soot are emitted. A wall-flow DPF (diesel particulate filter) is one of the most important technologies for diesel emission control. However, the soot accumulation inside the DPF causes an increase of pressure loss. Then, the accumulated diesel soot needs to be burned, which is called a filer regeneration process. In this study, we have investigated the soot combustion on bare and catalyzed DPFs under controlled and uncontrolled regeneration. Two types of DPFs with conventional square and hexagonal cells were used. Results show that, in comparison with the bare DPF, the regeneration efficiency of the catalyzed DPF is clearly higher, indicating a marked effect of catalysts. Independent of regeneration temperature, a greater increase in the regeneration efficiency of the catalyzed DPF was confirmed under controlled regeneration. On the other hand, under uncontrolled regeneration, the maximum temperature of the catalyzed DPF is higher than that of the bare DPF, and it is reached shorter times. Interestingly, by comparing the conventional square cell DPF, the soot oxidation of the hexagonal cell DPF is promoted under controlled and uncontrolled regeneration.