A plugged honeycomb structure includes a honeycomb structure body, and a plurality of plugging portions, the honeycomb structure body further includes pass-through hole portions each of which is formed in at least a part of a partition wall intersection portion in which the partition walls intersect in one end face and each of which interconnects a pair of cells facing each other at a position corresponding to the partition wall intersection portion to enable pass-through of a fluid, and a value obtained by dividing a diameter of a first virtual inscribed circle inscribed at a position of a minimum hole width of the pass-through hole portion by a diameter of a second virtual inscribed circle inscribed at a position of a minimum plugging width between the plugging portions facing each other is in a range of 0.05 to 0.74.

A honeycomb filter includes a honeycomb structure having a porous partition wall disposed to surround a plurality of cells; and a plugging portion provided at one end of the cell, wherein the honeycomb structure has an inflow side region including a range of up to at least 30% with respect to the total length of the honeycomb structure with the inflow end face as the starting point and an outflow side region including a range of up to at least 20% with respect to the total length of the honeycomb structure with the outflow end face as the starting point, in the extending direction of the cell of the honeycomb structure, an average pore diameter of the partition wall in the inflow side region is 15 to 20 μm and an average pore diameter of the partition wall in the outflow side region is 9 to 14 μm.

A honeycomb filter includes a honeycomb structure having a porous partition wall disposed to surround a plurality of cells; and a plugging portion provided at one end of the cell, wherein the honeycomb structure has an inflow side region including a range of up to at least 30% with respect to the total length of the honeycomb structure with the inflow end face as the starting point and an outflow side region including a range of up to at least 20% with respect to the total length of the honeycomb structure with the outflow end face as the starting point, in the extending direction of the cell of the honeycomb structure, an average pore diameter of the partition wall in the inflow side region is 9 to 14 μm and an average pore diameter of the partition wall in the outflow side region is 15 to 20 μm.

A method for producing a honeycomb-shaped ceramic structure by extrusion-molding a moldable material including a cordierite-forming material and a pore-forming material, wherein the cordierite-forming material contains 15-25% by mass of silica having an average particle size of 20-30 μm, with 5% or less by mass of particles having particle sizes of 10 μm or less and 5% or less by mass of particles having particle sizes of 100 μm or more, a particle size distribution deviation SD of 0.5 or less, and sphericity of 0.5 or more, and wherein the pore-forming material is present in an amount of 5-40% by mass based on the cordierite-forming material and has an average particle size of 15-50 μm, with 10% or less by mass of particles having particle sizes of 5 μm or less and 5% or less by mass of particles having particle sizes of 80 μm or more.

Provided is a particulate filter in which a PM collection rate is stably increased. The particulate filter according to the present invention includes a substrate 10 having a wall flow structure having a porous partition wall 16 that partitions an inlet cell and an outlet cell, and a wash coat layer held on surfaces of internal pores of the partition wall. In addition, average filling rates A, B, and C of the wash coat layer measured for each predetermined pore diameter range in the internal pores satisfy specific relationships. Further, the wash coat layer is formed in a region that occupies 50% or more of a thickness of the partition wall, and an amount of a noble metal catalyst carried by the wash coat layer is 0 g/L or more but 0.2 g/L or less.

An exhaust gas purification filter that is suitable for arrangement in an exhaust passage of an internal combustion engine and for collecting particulate matter contained in exhaust gas, comprises: exhaust gas inflow passages and exhaust gas outflow passages that are arranged alternately; and porous partitions that separate the exhaust gas inflow passages and the exhaust gas outflow passages from each other. Each of the partitions is divided into a coated zone in which a surface of a partition base is coated with a coating layer having a smaller average pore diameter than an average pore diameter of the partition base and a non-coated zone that is located on a downstream side of the coated zone and in which a surface of the partition base is not coated with the coating layer.

A partial wall-flow filter has an inlet end, an outlet end, and a plurality of parallel channels disposed and configured to flow fluid from the inlet end to the outlet end. The channels are defined by a plurality of porous walls. A first portion of the channels have a first hydraulic diameter Dh1, a second portion of the channels have a second hydraulic diameter Dh2 smaller than the first hydraulic diameter Dh1, and the ratio of Dh1:Dh2 is in the range of 1.1 to 1.6. At least a portion of channels having hydraulic diameter Dh1 are plugged at the outlet end, and channels having hydraulic diameter Dh2 are flow-through channels.

The invention relates to a wall-flow filter, to a method for the production and the use of the filter for reducing harmful exhaust gases of an internal combustion engine. The wall-flow filter was produced by exposing the filter at least twice successively to a powder-gas aerosol.

An exhaust emission control filter is provided that can reduce the pressure loss and has a high exhaust conversion performance and particulate matter capturing performance. An exhaust emission control filter includes: a filter base material having a wall flow structure; and an exhaust conversion catalyst carried on partitions of the filter base material. The median gas pore diameter (D50) of the filter base material after the exhaust conversion catalyst is carried on the filter base material is 17 μm or more. The half width of the gas pore distribution of the filter base material ranges from 7 to 15 μm. The exhaust conversion catalyst is ununiformly carried in a high-density layer having a relatively high density of the exhaust conversion catalyst and a low-density layer having a relatively low density of the exhaust conversion catalyst. The maximum gas pore diameter of the high-density layer is 11.7 μm or less.

To provide an exhaust gas purification filter having a high capability of collecting particulate matter. The exhaust gas purification filter includes a filter base material having a wall flow structure and an exhaust gas purification catalyst. A wash coating amount of the exhaust gas purification catalyst ranges from 60 to 110 g/L or less. When the exhaust gas purification filter is divided into an upstream part, a middle part, and a downstream part, and average values of catalyst area ratios of the exhaust gas purification catalyst supported by surfaces of the partition walls are acquired at predetermined locations in cells on an inflow side and cells on an outflow side, a minimum value, among the average values, is 28% or greater. A maximum value, among sizes of pores in the partition walls after the exhaust gas purification catalyst is supported, is 14.6 μm or less.