A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and porous plugging portions provided either at the ends on the inflow end face side or the outflow end face side of the cells, wherein the plugging portions are composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region, is higher than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portion ranges from 76% to 85%, and that of the circumferential plugging portion from 60% to 75%.

A honeycomb filter comprising a pillar-shaped honeycomb structure having a porous partition wall disposed so as to surround a plurality of cells which serve as a fluid through channel extending from an inflow end face to an outflow end face and a porous plugging portion provided at either an end on the inflow end face side or an end on the outflow end face side of the cell, wherein in a processed image obtained by binarizing an electron microscope image of a visual field area of 480 m640 m of the plugging portion, the plugging portion is composed of a plurality of particles, and the number of the particles having an area of 0.25 m.sup.2 or more is 1000 or more and 3500 or less.

A particulate filter for exhaust-gas aftertreatment in an internal combustion engine has a housing on which an inlet and an outlet are configured on opposite ends. The particulate filter also has a filter element arranged in the housing, said filter element having essentially parallel filter channels that are each alternatingly closed on the inlet side or on the outlet side by a closure in order to prevent gas from passing directly through the filter element. In this context, the filter channels can be divided into a first group of filter channels which are closed on the outlet side by a closure, and into a second group of filter channels which are closed on the inlet side by a gas-tight closure. The filter channels of the second group are additionally closed on the outlet side by a high-porosity closure in order to improve the cleaning effect of the particulate filter.

A honeycomb filter including: a pillar-shaped honeycomb structure including porous partition walls; and porous plugging portions disposed on either one of end portions of each of the cells, wherein a porosity (%) of the partition walls is defined as P1, a porosity (%) of the plugging portions is defined as P2, an occupancy (%) of the partition walls relative to an area of a cross section orthogonal to an extending direction of the cells of the honeycomb structure is defined as N1, the P1 is 50 to 65%, the P2 is 60 to 70%, the N1 is 22 to 39%, and X represented by Formula (1) satisfies a relation of Formula (2):
X=P1/P2N1,Formula (1):
18.800.19X.sup.2+11.33X121.6350.50.Formula (2):

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and porous plugging portions provided either at the ends on the inflow end face side or the outflow end face side of the cells, wherein the plugging portions are composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region, is higher than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portion ranges from 76% to 85%, and that of the circumferential plugging portion from 60% to 75%.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls placed, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face; and porous plugging portions provided either at the ends on the inflow end face side of the cells or at the ends on the outflow end face side of the cells, wherein the plugging portions include plugging portions that have voids therein, and in the plugging portions having the voids, porosity including the voids as pores ranges from 68% to 83%.

A honeycomb filter includes a pillar-shaped honeycomb structure having porous partition walls provided, surrounding a plurality of cells which serve as fluid through channels extending from an inflow end face to an outflow end face, and a porous plugging portion provided either at an end on the inflow end face or the outflow end face of the cells, wherein the plugging portion is composed of a porous material, the honeycomb structure has a central region and a circumferential region, and a ratio of an area of the circumferential region with respect to that of the central region ranges from 0.1 to 0.5, porosity of a central plugging portion in the central region is lower than that of a circumferential plugging portion in the circumferential region, and the porosity of the central plugging portions ranges from 60% to 68%, and that of the circumferential plugging portions ranges from 70% to 85%.

A plugged honeycomb structure has a plurality of cells defined by partition walls to become through channels for fluid, one end of each of the predetermined cells is plugged by a plugging member, the other end of each of the residual cells is plugged by the plugging member, the partition wall is made of a cordierite component as a main component, and a value obtained by dividing Young's modulus of a plugging structure portion formed by the partition walls and the plugging member by Young's modulus of a cell structure portion formed by the partition walls is in a range of 1.05 to 2.00.

A honeycomb filter includes a honeycomb structure including a porous partition wall surrounding cells, porous inflow side plugging portions and porous outflow side plugging portions. Each inflow side plugging portion includes, on an inflow side, a low porosity part having a porosity P1(%) of 70% or less and includes, on an outflow side, a high porosity part having a higher porosity than the low porosity part. The high porosity part has a porosity P2(%) satisfying P2(0.8904P3)+(0.7716N1)37.585, where P3(%) represents a porosity (%) of the partition wall; and N1(%) represents an open frontal area (%) of the cells, and the high porosity part has a length of 1 mm or more.

A honeycomb filter including: a pillar-shaped honeycomb structure including porous partition walls; and porous plugging portions disposed on either one of end portions of each of the cells, wherein a porosity (%) of the partition walls is defined as P1, a porosity (%) of the plugging portions is defined as P2, an occupancy (%) of the partition walls relative to an area of a cross section orthogonal to an extending direction of the cells of the honeycomb structure is defined as N1, the P1 is 50 to 65%, the P2 is 60 to 70%, the N1 is 22 to 39%, and X represented by Formula (1) satisfies a relation of Formula (2):

X=P1/P2N1,Formula (1):

18.800.19X.sup.2+11.33X121.6350.50.Formula (2):