A honeycomb filter includes: a honeycomb structure having porous partition walls disposed so as to surround cells, and plugging portions disposed at any one of ends on the inflow end face and the ends on the outflow end face, of cells. In a cross section perpendicular to an extending direction of the cells, a thickness T1 of the partition walls in a central portion including a center of gravity O of the cross section is 0.17 to 0.32 mm, a thickness T2 of the partition walls in an outer peripheral portion is 70 to 90% of the thickness T1, and the outer peripheral portion extends from an outer peripheral edge of the cross section of honeycomb structure by 6 to 12% of a radius r which is from the center of gravity O of the cross section to the outer peripheral edge.

A honeycomb filter includes a honeycomb structure body that has porous partition walls disposed so as to surround cells, and plugging portions that are disposed at any one of the ends on the inflow end face and the ends on the outflow end face. A cross-sectional shape of each of the inflow cells is octagonal and a cross-sectional shape of each of the outflow cells is quadrangular. An area ratio (S1/S2) of a cross-sectional area S2 of each of the outflow cells to a cross-sectional area S1 of each of the inflow cells is 1.40 to 2.20. The plugging portions have convex portions that protrude from the end faces on which the plugging portions are disposed, toward the outer sides, and have a protruding height H of 0.3 to 3.0 mm, and the plugging portions have a plugging depth L of 4.0 to 9.0 mm.

A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein a thickness of the partition wall is 0.217 mm or less, a porosity of the partition wall is 57 to 63%, an average pore diameter of the partition wall is 6 to 14 μm, a number per unit area of pores which exist at a surface of the partition wall and which have equivalent circle opening diameters exceeding 3 μm is 800 to 1500 /mm.sup.2, an average equivalent circle opening diameter of pores which exist at a surface of the partition wall and which have equivalent circle opening diameters exceeding 3 μm is 6.7 to 12.5 μm, and in a pore diameter distribution of the partition wall, D10 is 3.0 to 7.0 μm, D90 is 13.0 to 27.0 μm, and (Log (D90)-Log (D10))/Log (D50) is 0.75 or less.

A particulate filter having a honeycomb structure of a matrix of interconnected porous walls including inlet cells and outlet cells defining a plurality of inlet channels and outlet channels, respectively, wherein at least a portion of the outlet cells are larger than any of the inlet cells, and a cross-sectional shape of at least some of the outlet channels is rectangular. Honeycomb extrusion dies, honeycomb bodies, honeycomb structures, and methods of manufacture are described, as are other aspects.

A coated ceramic honeycomb body comprising a honeycomb structure comprising a matrix of intersecting porous walls forming a plurality of axially-extending channels, at least some of the plurality of axially-extending channels being plugged to form inlet channels and outlet channels, wherein a total surface area of the outlet channels is greater than a total surface area of the inlet channels, and wherein a catalyst is preferentially located within the outlet channels, and preferentially disposed on non-filtration walls of the outlet channels. Methods and apparatus configured to preferentially apply a catalyst-containing slurry to the outlet channels and non-filtration walls are provided, as are other aspects.

A method of manufacturing a ceramic honeycomb structure by mixing a ceramic precursor batch composition having a median particle diameter less than or equal to about 10 μm and at least one starch-based pore former having a median particle diameter greater than or equal to about 10 μm. The method also includes forming a mixture of ceramic precursor batch composition and a starch-based pore former into a green ceramic structure having a web structure, and firing the green ceramic structure to yield a ceramic honeycomb structure.

A coated ceramic honeycomb body comprising a honeycomb structure comprising a matrix of intersecting porous walls forming a plurality of axially-extending channels, at least some of the plurality of axially-extending channels being plugged to form inlet channels and outlet channels, wherein a total surface area of the outlet channels is greater than a total surface area of the inlet channels, and wherein a catalyst is preferentially located within the outlet channels. and preferentially disposed on non-filtration walls of the outlet channels. Methods and apparatus configured to preferentially apply a catalyst-containing slurry to the outlet channels and non-filtration walls are provided, as are other aspects.

A honeycomb filter includes: a honeycomb substrate having porous partition walls disposed so as to surround cells extending from an inflow end face to an outflow end face, an outer peripheral coating layer disposed so as to surround an outer periphery of the honeycomb substrate, and plugging portions that are disposed at any one of ends on the inflow end face and ends on the outflow end face, of the cells, wherein, the outer peripheral coating layer has an inflection point at which thermal expansion in thermal expansion behavior of the outer peripheral coating layer turns to contraction and a temperature T1 of which is 1000 to 1500° C., and the outer peripheral coating layer has a porosity P1 of 36 to 48%, and a thermal expansion coefficient C1 between 40 to 800° C. of 2.5 to 3.5×10.sup.-6 /°C.

A honeycomb body (300) including a plurality of radially-extending walls (322) intersecting with a plurality of circumferentially-extending walls (324), the plurality of radially-extending walls (322) and the plurality of circumferentially-extending walls (324) form a plurality of circumferential zones (334A, 334B, 334C) of cells (308). The plurality of circumferential zones (334A, 334B, 334C) of cells (308) includes a first zone of cells (334A) including two or more first rings of cells (330) and having a first cell density, and a second zone of cells (334B) including two or more rings of cells (330) having varying cell densities across the two or more rings of cells. Other structures and extrusion dies are disclosed.

A honeycomb filter includes a pillar-shaped honeycomb structure body having a porous partition wall disposed to surround a plurality of cells and a plugging portion, wherein the partition wall defining inflow cells includes partition wall parts making up sides of polygon that is sectional shape of each cell, the partition wall parts each having a surface that is a face defining the inflow cell, the partition wall part is either a first partition wall part loaded with the exhaust-gas purifying catalyst on the surface so that a percentage of the area loaded therewith exceeds 10%, or a second partition wall part loaded with the exhaust-gas purifying catalyst so that a percentage of the area loaded therewith is 10% or less, and the partition wall is configured to include one or more the first partition wall parts and one or more the second partition wall parts as the partition wall parts.