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Among the durability items of the DPF (Diesel Particulate Filter), high accumulated soot mass limit is important for the low fuel consumption and also for the robustness. In case of catalyzed DPF, it depends on the following two properties during soot regeneration. One is the lower maximum-temperature inside of the DPF during usual regeneration in order to preserve the catalyst performance. The other is the higher thermal resistance against the unusual regeneration of excess amount of soot. This paper presents the improvement in the soot mass limit of Si bonded SiC DPF. Maximum-temperature inside of the DPF was lowered by the improvement of thermal conductivity of the material, resulted from the controlling of the microstructure. Additionally the thermal resistance was improved by the surface treatment of the Si and SiC.

DPF substrate is exposed to high temperature during regeneration and to acid components in exhaust gas. Therefore, DPF material needs to have an excellent thermal shock resistance, thermal and chemical stability to the sulfuric acid. This paper presents the durability test results of the Si-SiC DPF material. In particular, thermal shock resistance, oxidation resistance and acid resistance parameters have been evaluated by comparison with recrystallized-SiC and cordierite materials. As the results, the strength of Si-SiC decreased between ΔT=500 and 600deg.C, while that of recrystallized-SiC decreased between ΔT=300 and 400deg.C. The result is attributed to the difference in the elastic modulus. About oxidation resistance, material properties of Si-SiC, compared between pre- and post- oxidation, have greater stability than those of recrystallized SiC. And naturally, both SiC materials have superior acid resistance to cordierite.