Improving of the Filtration and Regeneration Performance by the Sic-DPF with the Layer Coating of PM Oxidation Catalyst

DPF has become widely known as an indispensable after-treatment component for the purification of the particulate matter in the diesel exhaust gas. But, in order to correspond to further regulation strengthening such as carbon dioxide emission regulation and number-based particulate matter emission regulation, it must be necessary also for DPF to keep improving its performance.

In this study, it was examined how to improve both the filtration efficiency and the oxidation efficiency of PM regarding the catalyzed DPF. SiC-made 10mil/300cpsi-OctoSquare asymmetric cell structure was chosen for the DPF substrate and PM oxidation catalyst was coated on the surface of the filter wall as a layer with the device of the coating method.

As a result, it was found that the layer coated DPF has advantage on the filtration efficiency without soot accumulation and efficiency was similar to an uncoated one with 0.1 g/l soot loading. It was suggested that the layer coated DPF would satisfy the PM after-treatment with number-based viewpoint even with a clean DPF after regeneration. In addition, it was recognized that the layer coated DPF could decrease the regeneration temperature due to the improvement of the PM oxidation rate. It was confirmed that the key parameters to improve the soot oxidation by the catalyst were the filtration area of the DPF and the position of the catalyst. Both parameters improved the contact between the soot and the catalyst and the catalytic oxidation reaction proceeded faster.