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 comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein a thickness of the partition wall is 0.257 mm or less, a porosity of the partition wall is 52 to 57%, an average pore diameter of the partition wall is 6 to 13 .Math.m, 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 .Math.m 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 .Math.m is 8.0 to 12.0 .Math.m, and in a pore diameter distribution of the partition wall, D10 is 2.0 to 5.5 .Math.m, D90 is 13.0 to 25.5 .Math.m, and (Log(D90)-Log(D10))/Log(D50) is 0.84 or less.

A honeycomb filter comprising a pillar-shaped honeycomb structure body having a porous partition wall and a plugging portion, wherein, in a pore diameter distribution of the partition wall, in the case where the pore diameter (.Math.m) whose cumulative pore volume is 10% of the total pore volume is denoted by D10, the pore diameter (.Math.m) whose cumulative pore volume is 50% of the total pore volume is denoted by D50, and the pore diameter (.Math.m) whose cumulative pore volume is 90% of the total pore volume is denoted by D90, all of the following equations (1) to (6) are satisfied.

[00001]$\begin{array}{cc}3.9\mu \text{}\text{m<D10}& \text{­­­(1)}\end{array}$

[00002]$\begin{array}{cc}10.5\mu \text{}\text{m<D50<16}\text{.6}\mu \text{}\text{m}& \text{­­­(2)}\end{array}$

[00003]$\begin{array}{cc}\text{D90<38}\text{.7}\mu \text{}\text{m}& \text{­­­(3)}\end{array}$

[00004]$\begin{array}{cc}\left(\log \text{}\text{D90-logD10}\right)/\log \text{}\text{D50<0}\text{.80}& \text{­­­(4)}\end{array}$

[00005]$\begin{array}{cc}\log \text{}\text{D90}/\text{logD50<1}\text{.36}& \text{­­­(5)}\end{array}$

[00006]$\begin{array}{cc}\log \text{}\text{D50}/\text{logD10<1}\text{.56}& \text{­­­(6)}\end{array}$

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 surfaces of the partition walls that each face the inflow-side cell and/or 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 from 3 to 10% based on the apparent area of the catalyst portion present on the partition wall.

A honeycomb structure comprising a pillar-shaped honeycomb structure body having a porous partition wall disposed so as to surround a plurality of cells, wherein let that A denotes an absolute value of open frontal area (%) in a plane of the honeycomb structure body orthogonal to the extending direction of the cells and P denotes an absolute value of porosity (%) of the partition wall, the honeycomb structure has a value represented by the following expression (1) that is 0.05 to 0.12, let that D denotes an average pore diameter (m) of the partition wall and G denotes a geometric surface area (mm.sup.2/mm.sup.3) of the partition wall, the honeycomb structure has a value represented by the following expression (2) that is 8 to 50 (μm×mm.sup.2/mm.sup.3), and the honeycomb structure has a hydraulic diameter of the cells that is 1.1 mm or more,
(1−A/100)×(1−P/100),  Expression (1)
D×G.  Expression (2)

In an exhaust gas purification filter, a partition wall has communicating pores. Each communicating pore has a surface opening on the gas-inflow-side surface and a plurality of portions, each portion having a diameter being reduced and then increased from the surface opening, one of the portions, whose diameter is the smallest, being defined as an inlet neck portion. As viewed in cross section in a thickness direction of the partition wall, the surface opening of each communication pore has a diameter defined as a surface opening diameter, the inlet neck portion of each communication pore has a diameter defined as an inlet neck diameter. The inlet neck diameter is smaller than the surface opening diameter, and an average value of the inlet neck diameters is 15 μm or less. A surface opening ratio of the communicating pores in plan view of the gas-inflow-side partition wall surface is 40% or more.

A honeycomb structure includes a pillar-shaped honeycomb structure body having a porous partition wall and a circumferential wall, wherein in a section orthogonal to the extending direction of the cells of the honeycomb structure body, the shape of the cell is a polygonal shape with a corner having an arc shape, a thickness T1[mm] of the partition wall is 0.0500 to 0.1400 mm, a radius of curvature R1[mm] of the corner having the arc shape of the cell and the thickness T1[mm] of the partition wall satisfy the relationship of Equation (1), in the section orthogonal to the extending direction of the cells of the honeycomb structure body, the outer diameter of the honeycomb structure body is 190.5 to 355.6 mm, and a porosity of the partition wall is 20 to 40%.

0.0050≤R1×T1≤0.0150  Equation (1):

A honeycomb structure (110) includes intersecting porous walls (106). Inlet channels (108i) and outlet channels (108o) are formed by the intersecting porous walls (106), wherein the inlet channels (108i) comprise inlet hydraulic diameters (HDi) and the outlet channels (108o) comprise outlet hydraulic diameters (HDo). The inlet channels (108i) comprise inlet corners (220i) with inlet corner radii (Ri) and the outlet channels (108o) comprise outlet corners (2200) with outlet corner radii (Ro). A centerpost (124) is defined by adjacent opposing inlet corners (220i) of two of the inlet channels (108i) and adjacent opposing outlet corners (2200) of two of the outlet channels (108o). A first diagonal length (D1) is a shortest distance between the opposing outlet corners (220o) of the two outlet channels (108o) and a second diagonal length (D2) is a shortest distance between the opposing inlet corners (220i) of the two inlet channels (108i). The honeycomb structure (110) has certain aspect ratios D1:D2 depending on hydraulic diameter ratios HDi:HDo.

A honeycomb filter includes a plugged honeycomb structure body which has cell rows arranged along one direction, in a cross section of the honeycomb structure body and including a first cell row constituted of at least one of an inflow cell and an outflow cell, and a through-cell, and a second cell row including no through-cells. A width P1 (mm) of the first cell row, a width P2 (mm) of the second cell row and a curvature radius R (μm) of a curved shape of corner portions of a polygonal shape of each cell satisfy a relation of Equation (1) below: Equation (1): 0.4 (R/1000)/((P1+P2)/2) 100 20.

Provided is a honeycomb filter, including: a pillar-shaped honeycomb substrate having an inflow end face and an outflow end face and including a porous partition wall surrounding a plurality of cells; and a plugging portion disposed at any one of ends of the cells at the inflow end face and at the outflow end face. In a cross section orthogonal to an extending direction of the cells, inflow cells have a pentagonal or a hexagonal shape, and outflow cells have a square shape. The cells are configured that the inflow cells surround one outflow cell and one side of an inflow cell and one side of an adjacent outflow cell are parallel to each other. The partition wall is configured that thickness of a first partition wall disposed between the inflow cells and the outflow cells is larger than thickness of a second partition wall disposed between the inflow cells.