The invention concerns a method for unblocking pores in a metal zeolite based selective catalytic reduction (SCR) catalyst. The method includes filling, at least partially, the SCR catalyst with a liquid, the liquid being preferably distilled water. The method includes letting said liquid inside the SCR catalyst enough time to allow said liquid to dissolve, at least partially, the obstructions and to penetrate into the pores. The method includes heating the SCR catalyst at a temperature above the ebullition temperature of the liquid so as to vaporize the part of the liquid remained into the pores, and generate steam flows through the obstructions, the steam flows removing the obstructions and unblocking the pores, wherein no hydrocarbons are injected during the step of heating.

A substrate (11) of an exhaust gas purification catalyst (10) includes inflow-side cells (21), outflow-side cells (22), and porous partition walls (23), each separating the inflow-side cell and the outflow-side cell. Catalyst portions (14, 15) are provided on the surfaces of the partition walls that each face the inflow-side cell and/or the surfaces of the partition walls that each face the outflow-side cell. In a cross section vertical to an exhaust gas flow direction, the percentage of the total area of voids, each void satisfying the expression L/{2(πS).sup.1/2}≤1.1 (wherein L is the perimeter of the void in the cross section, and S is the area of the void in the cross section), is greater than 10% to 30% or less based on the apparent area of the catalyst portion present on the partition wall. The content of zirconium element in terms of oxide (amount of ZrO2) in the catalyst portions is from 35 mass % to 85 mass %.

An object of the present invention is to provide an exhaust gas purification catalyst composition and an exhaust gas purification catalyst, each of which includes a pyrochlore-type CeO.sub.2—ZrO.sub.2-based complex oxide having an improved oxygen storage capacity (particularly, an improved oxygen storage capacity after being exposed to a high temperature environment), and, in order to achieve the above-mentioned object, the present invention provides an exhaust gas purification catalyst composition and an exhaust gas purification catalyst, each of which contains a pyrochlore-type CeO.sub.2—ZrO.sub.2-based complex oxide that contains Y and Mg and thus exhibits an excellent oxygen storage capacity (particularly, an excellent oxygen storage capacity after being exposed to a high temperature environment).

A honeycomb structure includes a pillar-shaped honeycomb structure body which has porous partition walls disposed to surround a plurality of cells Among the partition walls surrounding one of the cells, each of the partition walls constituting two opposite sides of the cell sandwiched therebetween is provided with a projection which project to extend into the cell and which is continuously provided in a direction in which the cell extends, and the area S1 of one region of the cell divided by a virtual line that virtually connects distal ends of the two projections in a section of the honeycomb structure body, and the area S2 of the other region (S1≤S2) of the cell satisfy 70%≤S1/S2×100%.

The present invention relates to a particulate filter, in particular a particulate filter for use in an emission treatment system of an internal combustion engine. The particulate filter provides an advantageous combination of low back pressure and high fresh filtration efficiency.

An electrically heating converter includes: a pillar shaped honeycomb structure made of conductive ceramics, including: an outer peripheral wall; and a partition wall disposed on an inner side of the outer peripheral wall, the partition wall defining a plurality of cells, each of the cells penetrating from one end face to other end face to form a flow path; metal electrodes; conductive connecting portions arranged on a surface of the pillar shaped honeycomb structure; and a pressing member configured to press the metal electrodes against the conductive connecting portions, so that the metal electrodes are electrically connected to the pillar shaped honeycomb structure. Each of the conductive connecting portions has an electrical resistivity lower than that of the pillar shaped honeycomb structure.

There is provided an exhaust gas purification device that shows a high HC removal performance under a condition in which a rich air-fuel mixture is introduced. The exhaust gas purification device includes a substrate, a first catalyst layer, and a second catalyst layer. The substrate includes an upstream end and a downstream end. The first catalyst layer is disposed on a surface of the partition wall in an upstream region including the upstream end of the substrate. The second catalyst layer is disposed inside the partition wall in a downstream region including the downstream end of the substrate. The first catalyst layer contains a first metal catalyst and alumina-zirconia composite oxide. The second catalyst layer contains a second metal catalyst.

An exhaust gas heating system is provided, comprising a first end face, a second end face, a plurality of honeycomb segments, and a plurality of electrically nonconductive layers. Each honeycomb segment comprises an array of intersecting walls forming channels extending axially between the first end face and the second end face. The intersecting walls comprise an electrically conductive material. The heater further comprises a plurality of electrically nonconductive layers arranged between adjacent segments of the honeycomb segments. The arrays of intersecting walls of the honeycomb segments are electrically isolated from each other by the nonconductive layers. The exhaust gas heating system further comprises a coil wrapped around an external surface of the heater arranged between the first end face and the second end face. The exhaust gas heating system further comprises a DC to AC converter configured to supply the coil with an AC current.

The exhaust gas purification device includes a substrate, a first catalyst layer, and a second catalyst layer. The substrate includes an upstream end, a downstream end, and a porous partition wall defining a plurality of cells extending between the upstream end and the downstream end. The plurality of cells include an inlet cell opening at the upstream end and sealed at the downstream end, and an outlet cell adjacent to the inlet cell sealed at the upstream end and opening at the downstream end. The first catalyst layer is disposed on a surface of the partition wall in an upstream region. In a downstream region, the second catalyst layer is disposed inside the partition wall, and a second catalyst-containing wall including the partition wall and the second catalyst layer has a porosity of 35% or more.

A filter element for a particle filter having a porous filter body made of a ceramic material and including a plurality of flow channels extending fluidically in parallel. The filter body is provided at least in a part of the flow channels with a coating made of a coating material, which is different from the ceramic material and is made up of orthorhombic crystals. A particle filter, a method for producing a filter element, and the use of a coating material for coating a filter element is also provided.