JP2008212787A - Exhaust gas purification filter - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust gas purification filter capable of efficiently suppressing pressure loss during the use. <P>SOLUTION: The exhaust gas purification filter 1 comprises a honeycomb structure body 2 having a large number of cells 4 formed by arranging cell walls 3 in honeycomb state and clogging parts 5 clogging the downstream ends of the flow-inlet side cells 41 to lead the exhaust gas G in and the upstream ends of the flow-outlet side cells 42 to discharge the exhaust gas G out. The honeycomb structure body 2 has the total of the cross-sectional surface areas of paths of the flow-inlet side cells 41 based on the hydraulic diameter larger than the total of the cross-sectional surface areas of paths of the flow-outlet side cells 42 based on the hydraulic diameter in the a cross-section perpendicular to the longitudinal direction. The hexagonal cells 41, which are flow-inlet side cells, are arranged orderly in a manner that the apexes of the neighboring hexagonal cells 41 are set face to face at respective apexes and only the cell walls 3 composing mutual apexes are used in common. Triangular cells 42, the flow-outlet side cells 42 are installed in regions A formed among the hexagonal cells 41. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an exhaust gas purification filter that collects particulates in exhaust gas discharged from an internal combustion engine such as a diesel engine and purifies the exhaust gas.

2. Description of the Related Art Conventionally, an exhaust gas purification filter that collects particulates (hereinafter referred to as PM) in exhaust gas discharged from an internal combustion engine and purifies the exhaust gas is known.
This exhaust gas purification filter has a honeycomb structure as a base material in which porous cell walls are arranged in a honeycomb shape and a large number of cells are provided. Of the above-mentioned cells, the downstream end of the inflow side cell for allowing exhaust gas to flow in and the upstream end of the exhaust side cell for discharging exhaust gas that has passed through the porous cell wall are generally blocked by a plug. It is.

  When purifying exhaust gas using the exhaust gas purification filter, the exhaust gas flowing into the inflow side cell passes through the porous cell wall and moves to the exhaust side cell. At this time, PM in the exhaust gas is collected in a large number of pores existing on the cell wall, and the exhaust gas is purified. Thereafter, the purified exhaust gas is discharged from the discharge side cell. The collected PM is periodically burned and removed. Thereby, the collecting function of the porous cell wall is regenerated. Various known methods have already been proposed as the combustion removal method.

  By the way, in the exhaust gas purification filter, the cells on the inflow side and the exhaust side usually have the same shape and the same cross-sectional area. However, in such a structure, the pressure loss rapidly increases as PM trapped on the cell wall accumulates on the inflow side. Thereby, it leads to the performance fall of internal combustion engines, such as an engine. Further, the ash contained in the exhaust gas and generated due to the fuel is difficult to remove even if it is burned, so that an increase in pressure loss due to deposition becomes a particular problem.

Therefore, in order to solve the above-described problem, there has been proposed one in which the cross-sectional area of each inflow side cell is different from the cross-sectional area of each outflow side cell (see Patent Document 1). However, even in such a case, it cannot be said that an increase in pressure loss can be sufficiently suppressed.
Therefore, an exhaust gas purification filter that can effectively suppress an increase in pressure loss during use is desired.

JP-A-2005-270969

  The present invention has been made in view of such conventional problems, and an object of the present invention is to provide an exhaust gas purification filter capable of effectively suppressing pressure loss during use.

1st invention has the honeycomb structure which provided the porous cell wall in the shape of a honeycomb, and provided many cells, and it is the downstream of the inflow side cell used as the inflow side channel into which waste gas flows among these cells. In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a hexagonal cell that is a cell surrounded by the hexagonal cell wall,
The hexagonal cells are arranged with regularity so that the vertices of the adjacent hexagonal cells are opposed to each other at each vertex, and only the cell walls constituting the vertices are shared.
In the region formed between the hexagonal cells, a triangular cell that is a cell surrounded by the triangular cell wall is arranged,
In the exhaust gas purification filter, the hexagonal cell is the inflow side cell, and the triangular cell is the exhaust side cell.

  In the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. That is, in the exhaust gas purification filter, the inflow side channel cross-sectional area where PM in the exhaust gas is collected and deposited on the cell wall is made larger than the exhaust side channel cross-sectional area. Therefore, even if the amount of accumulated PM increases during use, the flow path cross-sectional area on the inflow side and the discharge side is substantially the same for a longer period of time than the conventional one where the flow cross-sectional area on the inflow side and the discharge side is almost the same. The increase in pressure loss can be moderated. Thereby, the pressure loss can be suppressed as a whole.

  The exhaust gas that passes through the exhaust gas purification filter contains ash generated due to fuel in addition to PM, and is deposited on the cell wall in the same manner as PM. This ash is difficult to remove by burning unlike PM. Therefore, as described above, the effect of suppressing an increase in pressure loss can be exhibited particularly effectively by making the flow passage cross-sectional area on the inflow side larger than that on the discharge side. As a result, the pressure loss can be kept low throughout the vehicle lifetime.

  In the exhaust gas purification filter of the present invention, as shown in FIG. 3 described later, the hexagonal cells that are the inflow side cells and the triangular cells that are the discharge side cells are regularly arranged without gaps. The triangular cells are arranged in a region formed by the hexagonal cells. By setting it as such a structure, exhaust gas can be made to pass through all the said cell walls which comprise the said cell, and PM in exhaust gas can be collected. That is, all the cell walls fulfill the PM trapping function. Thereby, the filtration area of exhaust gas can be secured sufficiently, and the initial pressure loss can be suppressed low.

  Thus, according to the present invention, it is possible to provide an exhaust gas purification filter that can effectively suppress an increase in pressure loss during use and can keep the pressure loss low overall.

A second invention has a honeycomb structure in which a porous cell wall is arranged in a honeycomb shape and a large number of cells are provided, and among the cells, downstream of an inflow side cell serving as an inflow side passage through which exhaust gas flows. In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a hexagonal cell that is a cell surrounded by the hexagonal cell wall,
The hexagonal cells are regularly arranged in the same direction in the vertical and horizontal directions, and in one direction, the adjacent hexagonal cells and the sides face each other, share the cell wall constituting the side, and the other In the direction, the adjacent hexagonal cells and vertices are opposed to each other, and are arranged so as to share only the cell walls constituting the vertices,
In the region formed between the hexagonal cells, a square cell that is a cell surrounded by the rectangular cell wall is arranged,
In the exhaust gas purification filter, the hexagonal cell is the inflow side cell, and the square cell is the exhaust side cell.

Also in the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. Therefore, as described above, even if the amount of accumulated PM increases during use, the increase in pressure loss can be moderated, and the pressure loss can be kept low overall.
In addition, the above-described effects can be exhibited particularly effectively against ash accumulation, and the pressure loss can be kept low throughout the vehicle lifetime.

  Further, in the exhaust gas purification filter of the present invention, as shown in FIG. 4 described later, the hexagonal cells that are the inflow side cells and the square cells that are the discharge side cells are regularly arranged without gaps. And the said square cell is arrange | positioned in the area | region enclosed and formed by the said hexagonal cell. By setting it as such a structure, the flow-path cross-sectional area by the side of discharge can fully be ensured, and a pressure loss can be suppressed.

  Here, the exhaust gas purification filter has an initial pressure loss because the cell walls that share sides with the adjacent hexagonal cells among the cell walls constituting the hexagonal cells do not perform the PM trapping function. May be high. However, if the pressure loss can be effectively suppressed by the above configuration, the pressure loss can be suppressed as a whole.

A third invention has a honeycomb structure in which a porous cell wall is arranged in a honeycomb shape and a large number of cells are provided, and among the cells, downstream of an inflow side cell serving as an inflow side passage through which exhaust gas flows. In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a hexagonal cell that is a cell surrounded by the hexagonal cell wall,
The hexagonal cells are regularly arranged in the same direction in the vertical and horizontal directions, and in one direction, the adjacent hexagonal cells and the sides face each other, share the cell wall constituting the side, and the other In the direction, the adjacent hexagonal cells and vertices are opposed to each other, and are arranged so as to share only the cell walls constituting the vertices,
In the region formed between the hexagonal cells, two triangular cells, which are triangular cells composed of the rectangular cell wall and the divided cell wall provided so as to divide the region, are arranged. ,
In the exhaust gas purification filter, the hexagonal cell is the inflow side cell, and the triangular cell is the exhaust side cell.

Also in the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. Therefore, as described above, even if the amount of accumulated PM increases during use, the increase in pressure loss can be moderated, and the pressure loss can be kept low overall.
In addition, the above-described effects can be exhibited particularly effectively against ash accumulation, and the pressure loss can be kept low throughout the vehicle lifetime.

  In the exhaust gas purification filter of the present invention, as shown in FIG. 5 described later, the hexagonal cells that are the inflow side cells and the triangular cells that are the discharge side cells are regularly arranged without gaps. Two triangular cells are arranged in a region formed by the hexagonal cells. By setting it as such a structure, the flow-path cross-sectional area by the side of discharge can fully be ensured, and a pressure loss can be suppressed.

  Here, in the exhaust gas purification filter, the cell walls that share a side with the adjacent hexagonal cell among the cell walls constituting the hexagonal cell, and the divided cells that constitute the triangular cell collect PM. Since it does not perform its function, the initial pressure loss may be increased. However, if the pressure loss can be effectively suppressed by the above configuration, the pressure loss can be suppressed as a whole.

4th invention has the honeycomb structure which arranged the porous cell wall in the shape of a honeycomb, and provided many cells, and the downstream of the inflow side cell used as the inflow side passage which makes exhaust gas flow in among the above-mentioned cells In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a circular cell that is a cell surrounded by the circular cell wall,
The circular cells are regularly arranged in the vertical and horizontal directions, and are arranged so as to share only the cell walls forming the vicinity of the contact points with the adjacent circular cells,
In the region formed between the circular cells, a quadrilateral cell that is a cell surrounded by the cell wall of the quadrilateral shape is arranged,
In the exhaust gas purification filter, the circular cell is the inflow side cell, and the four-pointed star cell is the discharge side cell.

Also in the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. Therefore, as described above, even if the amount of accumulated PM increases during use, the increase in pressure loss can be moderated, and the pressure loss can be kept low overall.
In addition, the above-described effects can be exhibited particularly effectively against ash accumulation, and the pressure loss can be kept low throughout the vehicle lifetime.

  In the exhaust gas purification filter of the present invention, as shown in FIG. 6 to be described later, the circular cell as the inflow side cell and the four-pointed star cell as the discharge side cell are regularly arranged without a gap. Yes. The four-pointed star cell having a sharp corner is arranged in a region formed by the circle cell. With such a configuration, the area of the cell wall that fulfills the PM collection function, that is, the filtration area of the exhaust gas can be increased. Therefore, the initial pressure loss can be kept low.

  In the present invention, the circular cells are arranged so as to share only the cell walls constituting the vicinity of the contact points with the adjacent circular cells. Actually, since the adjacent circular cells are not in contact with each other, the closest part is regarded as a contact, and the cell wall constituting the vicinity of the contact is shared.

5th invention has the honeycomb structure which arranged the porous cell wall in the shape of a honeycomb, and provided many cells, and is the downstream of the inflow side cell used as the inflow side passage which makes exhaust gas flow in among the above-mentioned cells. In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has an R square cell that is a cell surrounded by a rectangular cell wall having an R surface at a corner,
The R square cells are regularly arranged in the same direction in the vertical and horizontal directions, and are arranged so as to face the R square cells adjacent to each other and share the cell walls constituting the sides,
In a region formed between the R square cells, a quadrilateral cell that is a cell surrounded by the cell wall of a quadrilateral shape is arranged,
In the exhaust gas purification filter, the R square cell is the inflow side cell, and the four-pointed star cell is the discharge side cell.

Also in the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. Therefore, as described above, even if the amount of accumulated PM increases during use, the increase in pressure loss can be moderated, and the pressure loss can be kept low overall.
In addition, the above-described effects can be exhibited particularly effectively against ash accumulation, and the pressure loss can be kept low throughout the vehicle lifetime.

In the exhaust gas purification filter of the present invention, as shown in FIG. 7 to be described later, the R square cell as the inflow side cell and the four comet cell as the discharge side cell are regularly arranged without a gap. ing. Then, the four-pointed star cell having a sharp corner is disposed in a region formed by the R-square cell. With such a configuration, the area of the cell wall that fulfills the PM collection function, that is, the filtration area of the exhaust gas can be increased. Therefore, the initial pressure loss can be kept low.
Moreover, since the R surface is provided at the corner of the R square cell, the strength of the honeycomb structure can be improved.

A sixth invention has a honeycomb structure in which a porous cell wall is arranged in a honeycomb shape to provide a large number of cells, and among the cells, downstream of an inflow side cell serving as an inflow side passage through which exhaust gas flows. In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a circular cell that is a cell surrounded by the circular cell wall,
The circular cell is arranged at the position of each lattice point on the virtual hexagonal lattice line, and arranged so as to contact or share the adjacent circular cell and the cell wall constituting the vicinity of the mutual contact point. And
In the region formed surrounded by the circular cells, hexagonal cells that are cells surrounded by the hexagonal star-shaped cell wall are arranged,
In the exhaust gas purification filter, the hexagonal star cell is the inflow side cell, and the circular cell is the discharge side cell.

Also in the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. Therefore, as described above, even if the amount of accumulated PM increases during use, the increase in pressure loss can be moderated, and the pressure loss can be kept low overall.
In addition, the above-described effects can be exhibited particularly effectively against ash accumulation, and the pressure loss can be kept low throughout the vehicle lifetime.

In the exhaust gas purification filter of the present invention, as shown in FIG. 8 to be described later, the hexagonal star cell as the inflow side cell and the circular cell as the discharge side cell are regularly arranged without a gap. The hexagonal star cell having a sharp corner is disposed in a region formed by the circle cell. With such a configuration, the area of the cell wall that fulfills the PM collection function, that is, the filtration area of the exhaust gas can be increased. Therefore, the initial pressure loss can be kept low.
Moreover, by making the said discharge side cell into a circular cell, the flow-path cross-sectional area of a discharge side can fully be ensured, and a pressure loss can be suppressed.

  In the present invention, the circular cells are arranged so as to contact or share only the adjacent circular cells and the cell walls that form the vicinity of the mutual contacts. Actually, since the adjacent circular cells are not in contact with each other, the closest part is regarded as a contact, and the cell wall constituting the vicinity of the contact is in contact with or shared.

A seventh invention has a honeycomb structure in which a porous cell wall is arranged in a honeycomb shape and a large number of cells are provided, and among the cells, downstream of an inflow side cell serving as an inflow side passage through which exhaust gas flows. In the exhaust gas purification filter formed by closing the end and the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the cell wall,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a circular cell that is a cell surrounded by the circular cell wall,
The circular cell is arranged at the position of each lattice point on the virtual hexagonal lattice line, and arranged so as to contact or share the adjacent circular cell and the cell wall constituting the vicinity of the mutual contact point. And
In the region formed surrounded by the circular cells, hexagonal cells that are cells surrounded by the hexagonal star-shaped cell wall are arranged,
In the exhaust gas purification filter, the circular cell is the inflow side cell and the hexagonal star cell is the discharge side cell.

In the exhaust gas purification filter of the present invention, in the honeycomb structure, the sum of the flow path cross-sectional areas of the inflow side cells is larger than the sum of the flow path cross-sectional areas of the discharge side cells. Therefore, as described above, even if the amount of accumulated PM increases during use, the increase in pressure loss can be moderated, and the pressure loss can be kept low overall.
In addition, the above-described effects can be exhibited particularly effectively against ash accumulation, and the pressure loss can be kept low throughout the vehicle lifetime.

  In the exhaust gas purification filter of the present invention, as shown in FIG. 9 to be described later, the circular cell as the inflow side cell and the hexagonal star cell as the discharge side cell are regularly arranged without a gap. The hexagonal star cell having a sharp corner is disposed in a region formed by the circle cell. With such a configuration, the area of the cell wall that fulfills the PM collection function, that is, the filtration area of the exhaust gas can be increased. Therefore, the initial pressure loss can be kept low.

  In the present invention, the circular cells are arranged so as to contact or share only the adjacent circular cells and the cell walls that form the vicinity of the mutual contacts. Actually, since the adjacent circular cells are not in contact with each other, the closest part is regarded as a contact, and the cell wall constituting the vicinity of the contact is in contact with or shared.

In the first to seventh inventions, the hydraulic diameter means an equivalent hydraulic diameter, which is a diameter of a circular pipe equivalent to a cross section of a certain flow path. The equivalent hydraulic diameter is generally represented by 4a / L (a: cross-sectional area of flow path, L: cross-sectional length). And the flow-path cross-sectional area of the said inflow side cell and the said discharge side cell is calculated based on the hydraulic diameter of each cell.
The initial pressure loss refers to the pressure loss before the exhaust gas is passed through the exhaust gas purification filter.

In addition, when A is the sum of the channel cross-sectional areas based on the hydraulic diameter of the inflow side cell and B is the sum of the channel cross-sectional areas based on the hydraulic diameter of the discharge side cell, A / B = 1.1-5 It is preferable that
By setting the A / B within the above range, the effect of suppressing the pressure loss during use can be sufficiently exerted.

In addition, the honeycomb structure is preferably made of a ceramic whose main component is cordierite (Claim 8).
In this case, by using cordierite having a low thermal expansion coefficient, the honeycomb structure having excellent thermal shock resistance can be obtained. Furthermore, cordierite is inexpensive and can reduce manufacturing costs.

In addition, the porosity of the honeycomb structure is preferably 30 to 70%.
In this case, the purification performance of the filter can be increased while maintaining the pressure loss low. When the porosity is less than 30%, there is a problem that the pressure loss becomes high. On the other hand, when the porosity exceeds 70%, the problem is that the strength of the exhaust gas purification filter is reduced, and the purification performance of the filter is lowered. May cause problems.
The porosity can be measured by determining the pore volume by mercury porosimetry using a porosimeter.

Further, as the cross-sectional shape of the honeycomb structure, a generally used shape such as a circle or an ellipse can be adopted.
Further, the inflow side cell and the discharge side cell can be provided with R surfaces at the corners as necessary. In this case, the strength of the honeycomb structure can be improved. The R plane is a curved surface having a certain radius of curvature.
Moreover, the magnitude of the cross-sectional area (flow-path cross-sectional area) of each cell of the said inflow side cell and the said discharge side cell does not matter. That is, in the present invention, if the sum total of the channel cross-sectional area based on the hydraulic diameter of the inflow side cell is larger than the sum of the channel cross-sectional area based on the hydraulic diameter of the discharge side cell, the cross-sectional area of each cell can be varied. Can be set to

(Example 1)
An exhaust gas purification filter according to an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the exhaust gas purification filter 1 of this example has a honeycomb structure 2 as a base material in which a porous cell wall 3 is arranged in a honeycomb shape and a large number of cells 4 are provided. The honeycomb structure 2 is made of ceramics whose main component is cordierite, and has a cylindrical shape. Moreover, the porosity of the honeycomb structure 2 is 50%.

  In addition, as shown in FIG. 2, in the cell 4, the inflow side cell 41 serving as a passage through which the exhaust gas G flows is closed by the plug portion 5 at the downstream end 202 of the honeycomb structure 2. Further, the discharge side cell 42 that becomes a passage for discharging the exhaust gas G that has passed through the cell wall 3 is closed by the plug portion 5 at the upstream end 201 of the honeycomb structure 2. The cell wall 3 is formed with a large number of pores for collecting PM in the passing exhaust gas G.

Further, in the honeycomb structure 2, in the cross section orthogonal to the axial direction, that is, in the radial cross section, the sum of the flow cross-sectional areas based on the hydraulic diameter of the inflow side cell 41 is the flow path breakage based on the hydraulic diameter of the discharge side cell 42. The cell wall 3 and the cell 4 (inflow side cell 41, discharge side cell 42) are configured to be larger than the total area.
In this example, the inflow-side channel cross-sectional area A that is the sum of the channel cross-sectional areas based on the hydraulic diameter of the inflow-side cell 41 and the discharge-side flow that is the sum of the channel cross-sectional areas based on the hydraulic diameter of the discharge-side cells 42. The relationship with the road cross-sectional area B is A / B = 1.2.

Further, when the honeycomb structure 2 is viewed from the axial direction, as shown in FIGS. 3A and 3B, the inflow side cell 41 is a hexagonal cell configured to be surrounded by the hexagonal cell wall 3, The discharge side cell 42 is a triangular cell that is surrounded by the triangular cell wall 3. These hexagonal cells 41 and triangular cells 42 are regularly arranged without gaps.
Further, at the upstream end 201 of the honeycomb structure 2, the triangular cell 42 is closed by the plug portion 5 (FIG. 3A), and at the downstream end 202, the hexagonal cell 41 is closed by the plug portion 5. (FIG. 3B).

  As shown in the figure, the hexagonal cells 41 are arranged so that the vertices of the adjacent hexagonal cells 41 are opposed to each other at each vertex and only the vertex cell wall 31 that is the cell wall 3 constituting each vertex is shared. Yes. The hexagonal cell 41 in this example is arranged so as to be positioned at each lattice point 811 on the virtual triangular lattice line 81.

  The triangular cells 42 are arranged in a region formed between the hexagonal cells 41 as shown in FIG. The triangular cell 42 of this example is arranged in a triangular region S1 formed by being surrounded by three hexagonal cells 41. The triangular cell 42 is configured so as to be surrounded by the cell walls 3 constituting the hexagonal cell 41.

In manufacturing such an exhaust gas purification filter 1, a known method similar to the conventional one can be adopted as the manufacturing method itself. That is, a viscous cordierite raw material used as the material of the honeycomb structure 2 is extruded as a honeycomb-shaped formed body, cut into a predetermined length, and the formed body is dried and fired. In addition, in the process after or before the drying / firing, the raw material to be the plug portion 5 is disposed in the portion to be closed, and this is also dried / fired.
Here, what is peculiar to the exhaust gas purification filter 1 of this example is that a mold (not shown) provided with a slit corresponding to the cell wall 3 is used as the mold during the extrusion molding.

Next, the effect of the exhaust gas purification filter 1 of this example will be described.
In the exhaust gas purification filter 1 of this example, in the honeycomb structure 2, the sum of the flow path cross-sectional areas of the inflow side cells 41 is larger than the sum of the flow path cross-sectional areas of the discharge side cells 42. That is, the exhaust gas purification filter 1 has an inflow-side channel cross-sectional area where PM in the exhaust gas G is collected and deposited on the cell wall 3 larger than the exhaust-side channel cross-sectional area. Therefore, even if the amount of accumulated PM increases during use, the flow path cross-sectional area on the inflow side and the discharge side is substantially the same for a longer period of time than the conventional one where the flow cross-sectional area on the inflow side and the discharge side is almost the same. The increase in pressure loss can be moderated. Thereby, the pressure loss can be suppressed as a whole.

  The exhaust gas that passes through the exhaust gas purification filter 1 includes ash generated due to fuel in addition to PM, and is deposited on the cell wall 3 in the same manner as PM. This ash is difficult to remove by burning unlike PM. Therefore, as described above, the effect of suppressing an increase in pressure loss can be exhibited particularly effectively by making the flow passage cross-sectional area on the inflow side larger than that on the discharge side. As a result, the pressure loss can be kept low throughout the vehicle lifetime.

  Further, in the exhaust gas purification filter 1 of the present example, as described above, the hexagonal cells 41 that are the inflow side cells and the triangular cells 42 that are the discharge side cells are regularly arranged without gaps and are surrounded by the hexagonal cells 41. A triangular cell 42 is arranged in the region S1 to be processed. By setting it as such a structure, exhaust gas G can be passed through all the cell walls 3 which comprise the cell 4, and PM in exhaust gas G can be collected. That is, all the cell walls 3 perform the PM collecting function. Thereby, the filtration area of exhaust gas can be secured sufficiently, and the initial pressure loss can be suppressed low.

  Thus, according to this example, it is possible to provide an exhaust gas purification filter that can effectively suppress an increase in pressure loss during use and can keep the pressure loss low overall.

In addition, the inflow side cell 41 and the discharge side cell 42 can be provided with R surfaces at the corners as necessary. In this case, the strength of the honeycomb structure 2 can be improved.
The same applies to Examples 2 to 7 described later.

(Example 2)
In this example, the shape and arrangement of the inflow side cell 41 and the discharge side cell 42 are changed.
In this example, as shown in FIG. 4, the inflow side cell 41 is a hexagonal cell surrounded by the hexagonal cell wall 3, and the discharge side cell 42 is surrounded by the quadrangular cell wall 3. It is a configured square cell. The hexagonal cells 41 and the square cells 42 are regularly arranged without gaps.
Further, at the upstream end 201 of the honeycomb structure 2, the square cells 42 are closed by the plug portions 5 (FIG. 4), and at the downstream end 202, the hexagonal cells 41 are closed by the plug portions 5 (illustrated). Abbreviation).

  As shown in the figure, the hexagonal cells 41 are regularly arranged in the same direction in the vertical and horizontal directions. In this example, they are arranged so as to be positioned at the respective grid points 821 on the virtual square grid line 82. And in one direction, the hexagonal cell 41 faces the adjacent hexagonal cell 41 and shares the side cell wall 32 which is the cell wall 3 constituting the side, and in the other direction, The adjacent hexagonal cells 41 and the vertices face each other, and are arranged so as to share only the vertex cell wall 31 that is the cell wall 3 constituting the vertex.

The square cells 42 are arranged in a region formed between the hexagonal cells 41 as shown in FIG. The square cell 42 of this example is disposed in a rhombus-shaped region S <b> 2 formed by being surrounded by four hexagonal cells 41. The square cell 42 is configured to be surrounded by the cell walls 3 that form the hexagonal cell 41.
In addition, the relationship between the inflow side flow path cross-sectional area A and the discharge side flow path cross-sectional area B in this example is A / B = 4.
The other configuration is the same as that of the first embodiment and is manufactured by the same manufacturing method.

In the exhaust gas purification filter 1 of this example, as described above, the hexagonal cells 41 that are the inflow side cells and the square cells 42 that are the discharge side cells are regularly arranged without gaps and are surrounded by the hexagonal cells 41. Square cells 42 are arranged in the region S2. By setting it as such a structure, the flow-path cross-sectional area by the side of discharge can fully be ensured, and a pressure loss can be suppressed.
In other respects, the same effects as those of the first embodiment can be obtained.

  Here, in the exhaust gas purification filter 1, among the cell walls 3 constituting the hexagonal cell 41, the side cell wall 32 sharing the side with the adjacent hexagonal cell 41 does not perform the PM trapping function. May increase. However, if the pressure loss can be effectively suppressed by the above configuration, the pressure loss can be suppressed as a whole.

(Example 3)
In this example, the shape and arrangement of the inflow side cell 41 and the discharge side cell 42 are changed.
In this example, as shown in FIG. 5, the inflow side cell 41 is a hexagonal cell surrounded by the hexagonal cell wall 3, and the discharge side cell 42 is surrounded by the triangular cell wall 3. It is a configured triangular cell. These hexagonal cells 41 and triangular cells 42 are regularly arranged without gaps.
Further, at the upstream end 201 of the honeycomb structure 2, the triangular cell 42 is closed by the plug portion 5 (FIG. 5), and at the downstream end 202, the hexagonal cell 41 is closed by the plug portion 5 (illustrated). Abbreviation).

  As shown in the figure, the hexagonal cells 41 are regularly arranged in the same direction in the vertical and horizontal directions. In this example, it is arranged so as to be positioned at each grid point 831 on the virtual quadrangular grid line 83. And in one direction, the hexagonal cell 41 faces the adjacent hexagonal cell 41 and shares the side cell wall 32 which is the cell wall 3 constituting the side, and in the other direction, The adjacent hexagonal cells 41 and the vertices face each other, and are arranged so as to share only the vertex cell wall 31 that is the cell wall 3 constituting the vertex.

The triangular cells 42 are arranged in a region formed between the hexagonal cells 41 as shown in FIG. Two triangular cells 42 of this example are arranged in a diamond-shaped region S3 formed by being surrounded by four hexagonal cells 41. The triangular cell 42 is configured to be surrounded by a cell wall 3 constituting the hexagonal cell 41 and a divided cell wall 30 provided so as to divide the region S3.
In addition, the relationship between the inflow side flow path cross-sectional area A and the discharge side flow path cross-sectional area B in this example is A / B = 5.
The other configuration is the same as that of the first embodiment and is manufactured by the same manufacturing method.

In the exhaust gas purification filter 1 of this example, as described above, the hexagonal cell 41 that is the inflow side cell and the triangular cell 42 that is the discharge side cell are arranged with regularity without gaps, and are surrounded by the hexagonal cell 41. Two triangular cells 42 are arranged in the region S3. By setting it as such a structure, the flow-path cross-sectional area by the side of discharge can fully be ensured, and a pressure loss can be suppressed.
In other respects, the same effects as those of the first embodiment can be obtained.

  Here, in the exhaust gas purification filter 1, since the side cell wall 32 sharing the side with the adjacent hexagonal cell 41 does not perform the PM collecting function, the initial pressure loss may be increased. However, if the pressure loss can be effectively suppressed by the above configuration, the pressure loss can be suppressed as a whole.

Example 4
In this example, the shape and arrangement of the inflow side cell 41 and the discharge side cell 42 are changed.
In this example, as shown in FIG. 6, the inflow side cell 41 is a circular cell configured to be surrounded by a circular cell wall 3, and the discharge side cell 42 is surrounded by a quadrilateral cell wall 3. This is a four-pointed star cell. The circular cell 41 and the four-pointed star cell 42 are regularly arranged without gaps.
In addition, at the upstream end 201 of the honeycomb structure 2, the four-pointed star cell 42 is closed by the plug portion 5 (FIG. 6), and at the downstream end 202, the circular cell 41 is closed by the plug portion 5. (Not shown).

  As shown in the figure, the circular cells 41 are regularly arranged in the vertical and horizontal directions. In this example, they are arranged so as to be positioned at the respective lattice points 841 on the virtual rectangular lattice lines 84. The circular cell 41 is arranged so as to share only the contact cell wall 33 which is the cell wall 3 constituting the vicinity of the contact point with the adjacent circular cell 41.

The four-pointed star cell 42 is arranged in a region formed between the circular cells 41 as shown in FIG. The four-pointed star cell 42 of this example is arranged in a four-pointed star-shaped region S4 formed by being surrounded by four circular cells 41. The four-pointed star cell 42 is configured so as to be surrounded by the cell walls 3 constituting the circular cell 41, and has a shape with a sharp corner.
In addition, the relationship between the inflow side flow path cross-sectional area A and the discharge side flow path cross-sectional area B in this example is A / B = 5.
The other configuration is the same as that of the first embodiment and is manufactured by the same manufacturing method.

In the exhaust gas purification filter 1 of this example, as described above, the circular cell 41 that is the inflow side cell and the four-pointed star cell 42 that is the discharge side cell are regularly arranged without gaps and are surrounded by the circular cells 41. A four-pointed star cell 42 with sharp corners is arranged in the region S4. By setting it as such a structure, the area of the cell wall 3 which fulfill | performs PM collection function, ie, the filtration area of waste gas, can be ensured more largely. Therefore, the initial pressure loss can be kept low.
In other respects, the same effects as those of the first embodiment can be obtained.

(Example 5)
In this example, the shape and arrangement of the inflow side cell 41 and the discharge side cell 42 are changed.
In this example, as shown in FIG. 7, the inflow side cell 41 is an R square cell surrounded by a rectangular cell wall 3 having an R surface at the corner, and the discharge side cell 42 has a quadrilateral shape. This is a four-pointed star cell surrounded by the cell wall 3. The R square cell 41 and the four-pointed star cell 42 are regularly arranged without gaps.
Further, at the upstream end 201 of the honeycomb structure 2, the four-pointed star cell 42 is blocked by the plug portion 5 (FIG. 7), and at the downstream end 202, the R square cell 41 is blocked by the plug portion 5. (Not shown).

  As shown in the figure, the R square cells 41 are regularly arranged in the vertical and horizontal directions. In this example, it is arranged so as to be positioned at each grid point 851 on the virtual quadrangular grid line 85. The R square cell 41 is arranged so that the sides of the R square cell 41 are opposed to each other and share the side cell wall 32 which is the cell wall 3 constituting the side.

The four-pointed star cell 42 is arranged in a region formed between the R square cells 41 as shown in FIG. The four-pointed star cell 42 of this example is arranged in a four-pointed star-shaped region S5 formed by being surrounded by four R-square cells 41. The four-pointed star cell 42 is configured to be surrounded by the cell wall 3 that forms the R-plane of the R-square cell 41, and has a sharpened corner.
In addition, the relationship between the inflow side flow path cross-sectional area A and the discharge side flow path cross-sectional area B in this example is A / B = 6.
The other configuration is the same as that of the first embodiment and is manufactured by the same manufacturing method.

In the exhaust gas purification filter 1 of this example, as described above, the R square cell 41 that is the inflow side cell and the four-pointed star cell 42 that is the discharge side cell are regularly arranged without gaps, and are surrounded by the R square cell 41. In the region S5 formed in this manner, a four-pointed star cell 42 with sharp corners is arranged. By setting it as such a structure, the area of the cell wall 3 which fulfill | performs a PM collection function, ie, the filtration area of waste gas, can be taken larger. Therefore, the initial pressure loss can be kept low.
Moreover, since the R surface is provided at the corner of the R square cell 41, the strength of the honeycomb structure 2 can be improved.
In other respects, the same effects as those of the first embodiment can be obtained.

(Example 6)
In this example, the shape and arrangement of the inflow side cell 41 and the discharge side cell 42 are changed.
In this example, as shown in FIG. 8, the inflow side cell 41 is a hexagonal star cell surrounded by a hexagonal cell wall 3, and the discharge side cell 42 is surrounded by a circular cell wall 3. It is a constructed circle cell. These hexagonal star cells 41 and circular cells 42 are regularly arranged without gaps.
In addition, at the upstream end 201 of the honeycomb structure 2, the circular cell 42 is closed by the plug portion 5 (FIG. 8), and at the downstream end 202, the hexagonal star cell 41 is closed by the plug portion 5 (illustrated). Abbreviation).

  As shown in the figure, the circular cell 42 is disposed so as to be positioned at each lattice point 861 on the virtual hexagonal lattice line 86. The circular cell 42 is arranged so as to share the contact cell wall 33 which is the cell wall 3 constituting the vicinity of the contact point with the adjacent circular cell 42.

As shown in the figure, the hexagonal star cell 41 is arranged in a region formed by being surrounded by the circular cell 42. The hexagonal star cell 41 of this example is arranged in a hexagonal star-shaped region S6 formed by being surrounded by six circular cells 42. The six-pointed star cell 41 is configured to be surrounded by the cell walls 3 constituting the circular cell 42 and has a shape with a sharp corner.
In addition, the relationship between the inflow side flow path cross-sectional area A and the discharge side flow path cross-sectional area B in this example is A / B = 1.2.
The other configuration is the same as that of the first embodiment and is manufactured by the same manufacturing method.

In the exhaust gas purification filter 1 of this example, as described above, the hexagonal star cell 41 that is the inflow side cell and the circular cell 42 that is the discharge side cell are regularly arranged without gaps and are surrounded by the circular cells 42. A hexagonal star cell 41 with a sharp corner is arranged in the region S6. By setting it as such a structure, the area of the cell wall 3 which fulfill | performs a PM collection function, ie, the filtration area of waste gas, can be taken larger. Therefore, the initial pressure loss can be kept low.
Moreover, by making the discharge side cell 42 into a circular cell, it is possible to sufficiently secure the flow path cross-sectional area on the discharge side and to suppress pressure loss.
In other respects, the same effects as those of the first embodiment can be obtained.

(Example 7)
In this example, the shape and arrangement of the inflow side cell 41 and the discharge side cell 42 are changed.
In this example, as shown in FIG. 9, the inflow side cell 41 is a circular cell that is surrounded by a circular cell wall 3, and the discharge side cell 42 is surrounded by a hexagonal cell wall 3. This is a six-pointed star cell. These hexagonal star cells 41 and circular cells 42 are regularly arranged without gaps.
At the upstream end 201 of the honeycomb structure 2, the hexagonal star cell 42 is closed by the plug portion 5 (FIG. 8), and at the downstream end 202, the circular cell 41 is closed by the plug portion 5 (illustrated). Abbreviation).

  As shown in the figure, the circular cell 41 is arranged so as to be positioned at each lattice point 871 on the virtual hexagonal lattice line 87. The circular cell 41 is arranged so as to share the contact cell wall 33 which is the cell wall 3 constituting the vicinity of the contact point with the adjacent circular cell 41.

The hexagonal star cell 42 is arranged in a region formed by being surrounded by the circular cell 41 as shown in FIG. The hexagonal star cell 42 of this example is arranged in a hexagonal star-shaped region S7 formed by being surrounded by six circular cells 41. The six-pointed star cell 42 is configured to be surrounded by the cell walls 3 constituting the circular cell 41 and has a shape with a sharp corner.
In addition, the relationship between the inflow side channel cross-sectional area A and the discharge side channel cross-sectional area B in this example is A / B = 2.
The other configuration is the same as that of the first embodiment and is manufactured by the same manufacturing method.

As described above, the exhaust gas purification filter 1 of the present example is formed such that the circular cell 41 that is the inflow side cell and the six-pointed star cell 42 that is the discharge side cell are arranged with no regularity and surrounded by the circular cell 41. A hexagonal star cell 42 with sharp corners is arranged in the region S7. By setting it as such a structure, the area of the cell wall 3 which fulfill | performs a PM collection function, ie, the filtration area of waste gas, can be taken larger. Therefore, the initial pressure loss can be kept low.
In other respects, the same effects as those of the first embodiment can be obtained.

(Example 8)
In this example, the pressure loss during actual use was measured using the exhaust gas purification filter of the first embodiment (product of the present invention).
In this example, the exhaust gas purification filter of the present invention having an inflow side channel cross-sectional area A larger than an exhaust side channel cross-sectional area B is installed in a catalytic converter of an automobile exhaust gas purification system, and the catalytic converter has a flow rate of 20 g / sec. The exhaust gas was allowed to pass, and the difference between the inflow side pressure and the exhaust side pressure of the exhaust gas at that time was measured.
For comparison, an exhaust gas purification filter (conventional product) in which the inflow side channel cross-sectional area A and the discharge side channel cross-sectional area B are substantially the same was prepared and measured in the same manner.

The measurement results are shown in FIG. In the figure, the horizontal axis represents the PM deposition amount (g / L), and the vertical axis represents the pressure loss (kPa).
As can be seen from the figure, the product (E) of the present invention has a higher initial pressure loss than the conventional product (C). This is considered to be because the balance of the flow path cross-sectional area between the inflow side and the discharge side is lost because the inflow side flow path cross-sectional area A is made larger than the discharge side flow path cross-sectional area B. However, when the amount of accumulated PM increases, the pressure loss of the conventional product increases rapidly, whereas the pressure loss of the product of the present invention is moderate, and as a result, the pressure loss is lower than that of the conventional product. This tendency is the same in the accumulation of ash.
From the above results, it can be seen that the exhaust gas purification filter of the present invention can effectively suppress an increase in pressure loss during use and keep the pressure loss low overall.

FIG. 3 is an explanatory diagram showing an exhaust gas purification filter in Example 1. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory diagram showing an axial cross section of an exhaust gas purification filter in Example 1; Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell and discharge side cell in Example 1 ((a) upstream end of a honeycomb structure, (b) downstream end). Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell in Example 2, and the discharge side cell. Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell and discharge side cell in Example 3. FIG. Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell in Example 4, and the discharge | emission side cell. Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell and discharge side cell in Example 5. FIG. Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell in Example 6, and the discharge | emission side cell. Explanatory drawing which shows the shape and arrangement | positioning of the inflow side cell and discharge side cell in Example 7. FIG. Explanatory drawing which shows the relationship between PM deposition amount and pressure loss in Example 8. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Exhaust gas purification filter 2 Honeycomb structure 3 Cell wall 4 Cell 41 Inflow side cell 42 Outlet side cell 5 Plug part G Exhaust gas

Claims (9)

A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a hexagonal cell that is a cell surrounded by the hexagonal cell wall,
The hexagonal cells are arranged with regularity so that the vertices of the adjacent hexagonal cells are opposed to each other at each vertex, and only the cell walls constituting the vertices are shared.
In the region formed between the hexagonal cells, a triangular cell that is a cell surrounded by the triangular cell wall is arranged,
The exhaust gas purification filter, wherein the hexagonal cell is the inflow side cell, and the triangular cell is the exhaust side cell. A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a hexagonal cell that is a cell surrounded by the hexagonal cell wall,
The hexagonal cells are regularly arranged in the same direction in the vertical and horizontal directions, and in one direction, the adjacent hexagonal cells are opposed to each other, share the cell wall constituting the side, and the other In the direction, the adjacent hexagonal cells and vertices are opposed to each other, and are arranged so as to share only the cell walls constituting the vertices,
In the region formed between the hexagonal cells, a square cell that is a cell surrounded by the rectangular cell wall is arranged,
The exhaust gas purification filter, wherein the hexagonal cell is the inflow side cell, and the square cell is the exhaust side cell. A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a hexagonal cell that is a cell surrounded by the hexagonal cell wall,
The hexagonal cells are regularly arranged in the same direction in the vertical and horizontal directions, and in one direction, the adjacent hexagonal cells and the sides face each other, share the cell wall constituting the side, and the other In the direction, the adjacent hexagonal cells and vertices are opposed to each other, and are arranged so as to share only the cell walls constituting the vertices,
In the region formed between the hexagonal cells, two triangular cells, which are triangular cells composed of the rectangular cell wall and the divided cell wall provided so as to divide the region, are arranged. ,
The exhaust gas purification filter, wherein the hexagonal cell is the inflow side cell, and the triangular cell is the exhaust side cell. A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a circular cell that is a cell surrounded by the circular cell wall,
The circular cells are regularly arranged in the vertical and horizontal directions, and are arranged so as to share the cell walls forming the vicinity of the contact points with the adjacent circular cells,
In the region formed between the circular cells, a quadrilateral cell that is a cell surrounded by the cell wall of the quadrilateral shape is arranged,
The exhaust gas purification filter, wherein the circular cell is the inflow side cell and the four-pointed star cell is the exhaust side cell. A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has an R square cell that is a cell surrounded by a rectangular cell wall having an R surface at a corner,
The R square cells are regularly arranged in the same direction in the vertical and horizontal directions, and are arranged so as to face the R square cells adjacent to each other and share the cell walls constituting the sides,
In a region formed between the R square cells, a quadrilateral cell that is a cell surrounded by the cell wall of a quadrilateral shape is arranged,
The exhaust gas purification filter, wherein the R square cell is the inflow side cell, and the four-pointed star cell is the discharge side cell. A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a circular cell that is a cell surrounded by the circular cell wall,
The circular cell is arranged at the position of each lattice point on the virtual hexagonal lattice line, and arranged so as to contact or share the adjacent circular cell and the cell wall constituting the vicinity of the mutual contact point. And
In the region formed surrounded by the circular cells, hexagonal cells that are cells surrounded by the hexagonal star-shaped cell wall are arranged,
The exhaust gas purification filter, wherein the hexagonal star cell is the inflow side cell and the circular cell is the discharge side cell. A honeycomb structure having a plurality of cells provided with a porous cell wall arranged in a honeycomb shape, and among the cells, a downstream end of an inflow side cell serving as an inflow side passage through which exhaust gas flows, and the cell wall In the exhaust gas purification filter formed by closing the upstream end of the discharge side cell that becomes the discharge side passage for discharging the exhaust gas that has passed through the plug portion,
The honeycomb structure has a cross-sectional area perpendicular to the length direction, the sum of the flow path cross-sectional areas based on the hydraulic diameter of the inflow side cells is larger than the sum of the flow path cross-sectional areas based on the hydraulic diameter of the discharge side cells,
The cell has a circular cell that is a cell surrounded by the circular cell wall,
The circular cell is arranged at the position of each lattice point on the virtual hexagonal lattice line, and arranged so as to contact or share the adjacent circular cell and the cell wall constituting the vicinity of the mutual contact point. And
In the region formed surrounded by the circular cells, hexagonal cells that are cells surrounded by the hexagonal star-shaped cell wall are arranged,
The exhaust gas purifying filter, wherein the circular cell is the inflow side cell and the hexagonal star cell is the exhaust side cell.   The exhaust gas purification filter according to any one of claims 1 to 7, wherein the honeycomb structure is made of ceramics whose main component is cordierite.   The exhaust gas purification filter according to any one of claims 1 to 8, wherein the honeycomb structure has a porosity of 30 to 70%.

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