Disclosed is a honeycomb filter for collecting fine particles that includes a wall portion formed from a base material containing ceria-zirconia composite oxide and an inorganic binder. The wall portion has a gas permeability coefficient of 1.0 m.sup.2 or greater and 3.0 m.sup.2 or less.

A honeycomb filter includes a pillar-shaped honeycomb substrate including a porous partition wall that defines a plurality of cells extending from an inflow end face to an outflow end face, an inflow side plugging portion disposed at the inflow end face of the honeycomb substrate to plug open ends of outflow cells and an outflow side plugging portion disposed at the outflow end face of the honeycomb substrate to plug open ends of inflow cells other than the outflow cells. The honeycomb substrate includes the partition wall that defines two of the inflow cells by division. An average of the plugging length L.sub.IN of the inflow side plugging portions disposed in the outflow cells of the honeycomb substrate is larger than an average of the plugging length L.sub.OUT of the outflow side plugging portions disposed in the inflow cells of the honeycomb substrate.

A method for plugging a subset of cells of a honeycomb structure that includes: covering a first end face of the honeycomb structure with a mask that comprises a body and a plurality of openings, wherein the plurality of openings of the mask is coincident with a plurality of cells of the honeycomb structure; providing a plug of material upon a film material; applying a force to the film material with a piston to push the plug of material through the plurality of openings of the mask and into the plurality of cells of the honeycomb structure; and measuring a plurality of pressures within the plurality of cells of the honeycomb structure during the applying step.

A method of plugging channels of a honeycomb body and a honeycomb body including plugged channels. The method includes applying a shear force to a plugging mixture including a plurality of inorganic particles, clay, and a liquid vehicle to alter the viscosity of the plugging mixture from a first viscosity prior to the vibrating to a second viscosity which is less than the first viscosity. A honeycomb body is placed into contact with the plugging mixture such that a portion of the plugging mixture having the second viscosity flows into the plurality of channels. Application of the shear force is stopped or reduced to increase the viscosity of the portion of the plugging mixture in the plurality of channels to greater than the first viscosity.

A honeycomb filter includes a pillar-shaped honeycomb substrate including a porous partition wall that defines a plurality of cells extending from an inflow end face to an outflow end face, an inflow side plugging portion disposed at the inflow end face of the honeycomb substrate to plug open ends of outflow cells; and an outflow side plugging portion disposed at the outflow end face of the honeycomb substrate to plug open ends of inflow cells other than the outflow cells. The honeycomb substrate includes the partition wall that defines two of the inflow cells by division. An average of the plugging length L.sub.OUT of the outflow side plugging portions disposed in the inflow cells of the honeycomb substrate is larger than an average of the plugging length L.sub.IN of the inflow side plugging portions disposed in the outflow cells of the honeycomb substrate.

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):

A method of plugging a honeycomb body is disclosed herein, the method comprising: applying a mask layer to a honeycomb body comprising a plurality of channels; forming a plurality of holes in the mask layer such that the plurality of holes are aligned with the plurality of channels; positioning a nozzle defining an opening proximate the mask layer; moving at least one of the nozzle and the honeycomb body relative to one another; and passing a plugging cement through the opening defined by the nozzle against the mask layer such that the plugging cement passes through the plurality of holes in the mask layer and enters the plurality of channels of the honeycomb body.

An emissions control substrate for treating exhaust from an engine including a plurality of hexagonal cells extending between a first end and a second end of the substrate. Wash coats are at an interior of the hexagonal cells. At an inner region of the substrate through which a longitudinal axis of the emissions control substrate extends, for every group of three adjacent hexagonal cells of the plurality of hexagonal cells two are plugged at the first end and open at the second end, and one is open at the first end and plugged at the second end. At an outer region of the substrate surrounding the inner region, for every group of three adjacent hexagonal cells of the plurality of hexagonal cells, one is plugged at the first end and open at the second end, and two are open at the first end and plugged at the second end.

A honeycomb structural body includes: a porous cell wall that partitions a cylindrical casing; and a large number of cells extending in the axial direction X thereof and alternately blocked at an upstream end face. The large number of cells include plugged cells having plugs and penetrating cells that do not have the plugs. The plugged cells and the penetrating cells both include complete cells and incomplete cells. At least some of plugged incomplete cells of the incomplete cells have a cross-sectional area smaller than a cross-sectional area of penetrating complete cells, and are configured as blocked cells that are entirely blocked inside in the axial direction.