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As regulations on exhaust gas become stricter, it is desirable that catalytic converters be mounted directly under the engine. Accordingly, in order to improve the reliability of the alumina mat specifications under dynamic load conditions, the compatibility between the vibration conditions and the alumina mat specifications was examined. Through this examination, it was found out that the compatibility could be adjusted by vibration load applied per alumina mat, regardless of the shape of the catalytic carrier. Further, it was found that the fatigue life of the alumina mat complies with that of the ceramic materials.

Diesel emission regulation becomes stringent more and more regarding both particulate matter (PM) and NOx in the worldwide. SCR coated DPF system is considered as one of the promising options for future diesel exhaust after-treatment because it has several benefits such as the downsizing of the system, quick light-off of the catalytic function due to mounting closed-couple position. To integrate the SCR converter into the DPF, it is necessary to design the DPF substrate's porosity higher and pore size larger than conventional DPF to improve SCR catalyst coating capability. However to make the porosity higher will lose the robustness in general. Against these problems, it was studied to improve the high porosity DPF performances by applying the new technology to modify the thermal shock resistance property.

A new alumina mat for a ceramic catalytic converter was developed which is capable of reliably holding a ceramic catalyst carrier up to 900°C. This alumina mat is composed of a fibrous material consisting of 80% by weight of Al2O3 and 20% by weight of SiO2, provides a high surface pressure. The mat has a packing density of 0.2-0.4g/cm3, and can provide not only reliable catalyst holding but also weather resistibility and exhaust gas interception. The mat also has a structural reliability based on the ceramic fatigue theory.