Denso Corporation

Hiroaki Kayama

Kazuhiko Koike

Keisuke Mizutani

An exhaust gas purification filter is used so as to support a NOpurification catalyst. The exhaust gas purification filter includes a honeycomb structure portion and a plug portion. The honeycomb structure portion includes a partition wall and cells. Numerous pores are formed in the partition wall. The cells are partitioned by the partition walls and form a flow path for an exhaust gas. The plug portion alternately seals an inflow end surface or an outflow end surface for the exhaust gas in the cells. The partition wall has a gas permeability coefficient that is equal to or greater than 0.35×10m, a pore volume ratio of pore diameters of 9 μm or less that is equal to or less than 25%, and an average pore diameter that is equal to or greater than 12 μm.

Exhaust gas purification filter

An exhaust gas purification filter includes a plurality of cells extending in a filter axial direction, a porous partition separating and defining the plurality of cells, and a sealing section sealing the plurality of cells alternately at both filter ends. In the exhaust gas purification filter, the partition has a void volume of a reduced dale, Vvv, and a material volume of a reduced peak, Vmp, as volume parameters determined in noncontact surface roughness measurement on a surface of the partition, with their total value being 1.8 μm/μmor less.

An exhaust gas purification filter includes a plurality of cells extending in a filter axial direction, a porous partition separating and defining the plurality of cells, and a sealing section sealing the plurality of cells alternately at both filter ends. The partition has a void volume of a reduced dale, Vvv, and a material volume of a reduced peak, Vmp, as volume parameters determined in noncontact surface roughness measurement on a surface of the partition, with their total value being more than 1.3 μm/μmand 1.7 μm/μmor less. The partition has a mean pore size of 12 μm or more and 20 μm or less. The partition also has a porosity of 50% or more and 75% or less.

Provided is an exhaust gas purifying filter used with a HC purifying catalyst supported thereon. Numerous pores are formed in partitions of the exhaust gas purifying filter. In a cross-section of the partition, pores are open at a passage surface, having an open end of which the opening diameter is 50 &#x3bc;m or larger. In the cross-section of the partitions, the partitions include a narrow part where a pore diameter is 5 &#x3bc;m or more and the pore diameter becomes a minimum in a region. In the cross-section of the partitions, the region is positioned between a pair of virtual lines Land Lextending from opposing sides of the opening end to a passage surface positioned opposite to the opening end along the wall thickness direction X, Z. The pore diameter at the narrow part is 6% or more and less than or equal to 20% of the opening diameter.

Exhaust gas purifying filter

A honeycomb structure body has a skin part of a cylindrical shape and a honeycomb structural part formed with the skin part together in a monolithic body. The skin part and the honeycomb structural part have partition walls of a porous structure. The cells have first cells arranged adjacent to the skin part and second cells arranged adjacent to the first cells. The skin part, the first cells and the second cells form an outer peripheral section. A central section is arranged inside the outer peripheral section. The honeycomb structure body satisfies a relationship in which a thermal expansion coefficient of the outer peripheral section is greater than a thermal expansion coefficient of the central section.

Honeycomb structure body

A honeycomb structure body has an outer skin, cells arranged in an inside of the outer skin, and partition walls having pores. The partition walls are arranged in the inside of the outer skin. Each of the cells is surrounded by the partition walls. The pores have communicating pores which communicate with each other adjacent cells. Exhaust gas emitted from an engine passes adjacent cells through the communicating pores. The number of the communicating pores is at a density of not less than 18000 [pores/0.25 mm] before a catalyst is supported in the pores. An exhaust gas purification filter having the honeycomb structure body with the catalyst is arranged in an exhaust gas pipe to purify exhaust gas containing PM emitted from an engine.

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Kariya, Japan

Hiroaki Kayama