The present invention relates to a particulate filter which comprises a wall flow filter of length L and two different catalytically active coatings Y and Z, wherein the wall flow filter comprises channels E and A that extend in parallel between a first and a second end of the wall flow filter and are separated by porous walls which form the surfaces O.sub.E and O.sub.A, respectively, and wherein the channels E are closed at the second end and the channels A are closed at the first end. The invention is characterized in that the coating Y is located in the channels E on the surfaces O.sub.E and the coating Z is located in the channels A on the surfaces O.sub.A.

A honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, wherein the partition walls have projecting portions, in the cells of 10% or more of the plurality of cells, the projecting portions project into the cells, a tip curvature radius R of an apex of each of the projecting portions is from 0.01 to 0.1 mm, side surfaces of the projecting portions are inclined to the surfaces of the partition walls at an inclination angle of 40 to 70, and a relation of 0.04H/A0.4 is satisfied.

Various structures for catalytic convertors are disclosed herein. The device includes an outer housing enclosing a catalytic core. The catalytic core can be formed in a myriad of ways. Flow paths through the core are constructed so that they are not straight-line paths from the inlet of the device to the outlet of the device. Zigzag conformations and stacked panel arrays are described that maximize the catalytic surface area in a given volume of housing.

A honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, wherein the partition walls have projecting portions, the sectional area SA and the sectional area SB satisfy a relation of Formula (1) mentioned below, the number NA of the projecting portions and the number NB of the projecting portions satisfy a relation of Formula (2) mentioned below, Formula (1): <(the sectional area SA/the sectional area SB)<3, and Formula (2): 0(the number NB of the projecting portions/the number NA of the projecting portions)<1.

A honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, wherein the partition walls have projecting portions, the projecting portions include specific projecting portions in which side surfaces have a divergent shape inclined at an inclination angle of 40 to 70, a relation of 0.04H/A0.40 is satisfied, a relation of 0.04H.sub.1/A0.38 is satisfied, the height H of the specific projecting portion and the height H.sub.1 of the hem satisfy a relation of H.sub.1<H, and a ratio of a total number of the specific projecting portions is 2.5% or more.

Ceramic honeycomb bodies and methods for canning the bodies are disclosed herein. The honeycomb bodies comprise a porous ceramic honeycomb structure. The honeycomb structure comprises a network of cells defined by walls that extend in an axial direction about a longitudinal axis from an inlet end to an outlet end of the honeycomb structure. The honeycomb structure also comprises a portion of cells with protrusions. The portion of cells with protrusions supports a greater concentration of catalyst, as compared to a portion of cells without protrusions. The portion of cells with protrusions is disposed off-center with respect to the longitudinal axis of the honeycomb structure such that the portion of cells with protrusions (and greater concentration of catalyst) corresponds to areas of high exhaust flow through the structure.

The invention provides: an exhaust-gas-purifying metal substrate capable of achieving both low pressure loss and high purification performance; and an exhaust gas purification device using the metal substrate. The invention relates to an exhaust-gas-purifying perforated metal substrate in which a corrugated foil and a flat foil are layered and made into a cylindrical shape, wherein: the perforated metal substrate includes from 50/in2 to 800/in2 of cells; the corrugated foil includes a plurality of first holes having an area that is from 2.0 to 50 times the average opening area of the cells; the flat foil includes a plurality of second holes having an area that is from 3.0 to 100 times the average opening area of the cells; and the average value of the area of the first holes in the corrugated foil is smaller than the average value of the area of the second holes in the flat foil.

A honeycomb structure includes a pillar-shaped honeycomb structure body having porous partition walls, wherein the partition walls have projecting portions, a shape of each cell is polygonal, in the polygonal cell, the projecting portions are disposed on two sides extending from a corner of the cell, respectively, the projecting portions are non-uniformly arranged, a relation of Formula (1) is satisfied, and a ratio of a total number of the corners is 2.5% or more: Formula (1): 1/(N+1)<A/L.

A honeycomb structure including: a honeycomb structure body having porous partition walls which are disposed to surround a plurality of cells and a circumferential wall, wherein the partition walls are provided with protrusions, at least one of the plurality of cells includes a specific cell configured so that the protrusions protrude into the cell from the respective partition walls, and the specific cell is provided with a porous material made of the same material as the partition walls in a range of 5 to 50% including an intersection with respect to a pentagonal area which is formed by connecting the intersection when two partition walls configuring the peripheral edge of the specific cell extend and two points of bottom parts and top parts, respectively, of the respective protrusions disposed on the two partition walls, in the cross section orthogonal to the extending direction of the cells.

A honeycomb structure includes a porous partition wall disposed so as to surround cells extending from a first end face to a second end face. The cells include partially clogged cells which account for 10 to 80% of the total number of the cells, and each of which includes a protrusion that protrudes inward from the surface of the partition wall. The protrusion is partially formed in a direction in which each partially clogged cell extends. In a projected view from the first end face to the second end face, a ratio of area of the protrusion in each partially clogged cell to whole area of the through channel of each partially clogged cell is 5 to 80%, the whole area including the protrusion, and the partition wall surrounding each partially clogged cell has a thickness at a thinnest part of 0.038 mm or more.