JP5053224B2 - Exhaust purification filter - Google Patents

Description

  The present invention relates to an exhaust purification filter, and more particularly to a filter that collects particulates (particulate matter) discharged from an internal combustion engine.

  A technique of providing an exhaust gas purification filter for collecting particulates in an exhaust system of an internal combustion engine to reduce the amount of particulate emissions is widely used. In recent years, so-called wall flow type filters are mainly used as exhaust purification filters. The wall flow type exhaust gas purification filter includes a honeycomb structure in which a plurality of cells serving as exhaust gas flow paths are partitioned by a porous wall, and particulates are collected by the porous wall. The collected particulates are burned by raising the temperature of the exhaust purification filter.

  For example, when silicon carbide (SiC) is used as the material for such an exhaust purification filter, cracks are likely to occur in the porous wall due to thermal stress generated when the particulates are burned. Therefore, a technique for forming a honeycomb structure as an aggregate of a plurality of segments has been proposed in order to reduce thermal stress (see Patent Document 1).

FIG. 8 is a partial cross-sectional view showing the configuration of the exhaust purification filter 9.
FIG. 9 is a top view showing the configuration of the exhaust purification filter 9, that is, the view of the exhaust purification filter 9 as viewed from the upstream side of the exhaust gas.
The exhaust purification filter 9 is formed by housing a columnar honeycomb structure 91 in a cylindrical casing 92. Here, the honeycomb structure 91 is formed by preparing a plurality of segments 94 in which a plurality of cells 93 are formed as described above, and joining these segments 94. Further, in order to stably fix the honeycomb structure 91 inside the casing 92, a band-shaped holding material 95 is wound around the outer peripheral surface of the honeycomb structure 91, and circular shapes are formed on both ends of the honeycomb structure 91. An annular mesh ring 96 is attached and inserted into the casing 92.
International Publication WO2003-31371

  However, as shown in FIG. 9, in the conventional exhaust purification filter 9, when the honeycomb structure 91 is fixed to the inside of the casing 92 by the mesh ring 96, the cells 93 on the outer peripheral surface side of the honeycomb structure 91 become the mesh ring 96. The exhaust gas is unlikely to flow into these cells 93. That is, the cell 93 processed on the outer peripheral surface side is not effectively used, and the cost for processing is wasted.

FIG. 10 is a partial cross-sectional view showing the configuration of the end side of the exhaust purification filter 9.
As described above, since the honeycomb structure 91 is formed by joining a plurality of segments 94, unevenness may be formed on the end surface of the honeycomb structure 91. Therefore, for example, when the segment 94 on the outer peripheral surface side of the honeycomb structure 91 protrudes greatly, the load is likely to concentrate on the end surface of the segment 94 protruding from the mesh ring 96 as shown by an arrow 97 in FIG. End up. For this reason, the honeycomb structure 91 is likely to be cracked or chipped by vibration. In particular, if a crack occurs in the porous wall that partitions the cell 93, the exhaust gas easily flows from the cracked portion to the downstream side, so that the collection ability of the exhaust purification filter may be greatly reduced.

  The present invention has been made in view of the above-described problems, and provides an exhaust gas purification filter that can uniformly flow exhaust gas into a processed cell and that is less likely to crack or chip in a honeycomb structure. Objective.

  In order to achieve the above object, an invention according to claim 1 is an exhaust purification filter (1, 1A, 1B) that is disposed in an exhaust passage of an internal combustion engine and collects particulates discharged from the internal combustion engine. , A plurality of segments (21) having a plurality of cells (22) partitioned by a porous wall (23), and a columnar honeycomb structure (2, 2A, 2) formed by joining the plurality of segments 2B), and at least part of the outer peripheral portion of the honeycomb structure is provided with thick portions (25, 25A) in which no cells are formed, and the thickness (T) of the thick portion is The honeycomb structure is characterized by being 1% or more and 5% or less with respect to the diameter (L) of the portion where the cells are formed.

  According to a second aspect of the present invention, there is provided an exhaust purification filter (1B) according to the first aspect, wherein a plurality of segments (215) constituting the outer peripheral portion of the honeycomb structure (2B) are joined together ( The thickness of 261B) is larger than the thickness of the joint portion (262B) that joins the plurality of segments (216) that constitute other than the outer peripheral portion of the honeycomb structure.

  The invention according to claim 3 is the exhaust purification filter (1A) according to claim 1 or 2, wherein the thick portion (25A) includes a plurality of segments (212, 212) constituting an outer peripheral portion of the honeycomb structure. 213), it is provided only on the outer peripheral portion of the segment (212) whose sectional area of the section perpendicular to the cell extending direction is small.

  The invention according to claim 4 is the exhaust purification filter according to any one of claims 1 to 3, wherein the upstream side and the downstream side of the honeycomb structure, or the upstream side and the downstream side, It further includes an annular mesh member (5, 6) that is locked to the thick portion and supports the honeycomb structure.

  In order to achieve the above object, an invention according to claim 5 is an exhaust purification filter (1, 1A, 1B) disposed in an exhaust passage of an internal combustion engine and collecting particulates discharged from the internal combustion engine. , A plurality of segments (21) having a plurality of cells (22) partitioned by a porous wall (23), and a columnar honeycomb structure (2, 2A, 2) formed by joining the plurality of segments 2B) and an annular mesh member (5, 6) that is engaged with and supported by the outer peripheral portion of the honeycomb structure, and at least part of the outer peripheral portion of the honeycomb structure Is provided with thick portions (25, 25A) in which cells are not formed, and the mesh member is locked to the thick portions and does not block the cells of the honeycomb structure.

According to the first aspect of the present invention, the thick portion where the cells are not formed is provided in at least a part of the outer peripheral portion of the columnar honeycomb structure. Further, the thickness of the thick portion was set to be 1% or more and 5% or less with respect to the diameter of the portion where the cells were formed in the honeycomb structure.
Here, in the honeycomb structure formed as an assembly of a plurality of segments, the segments constituting the outer peripheral portion of the honeycomb structure are more susceptible to vibration transmission than the segments constituting the central portion of the honeycomb structure. , Cracks and chips are likely to occur. By providing a thick portion at the outer peripheral portion of such a honeycomb structure, the strength of the segment on the outer peripheral portion side can be improved, and the honeycomb structure can be less likely to be cracked or chipped.

  Here, it is assumed that the honeycomb structure is fixed inside the casing by the mesh ring as described above. In this case, in the present invention, a thick portion having a thickness of 1% or more and 5% or less with respect to the diameter of the portion where the cells are formed in the honeycomb structure is provided on at least a part of the outer peripheral portion of the honeycomb structure. The mesh ring can be locked only to the thick portion so as not to block the cells of the honeycomb structure. This allows exhaust gas to flow evenly into the processed cells and prevents the vibration of the casing from being transmitted directly to the segment via the mesh ring, making it difficult for cracks and chips to occur in the honeycomb structure. can do. Further, for example, even when a crack or a chip occurs in the thick part, no cell is formed in the thick part, so that the particulate collection ability of the exhaust purification filter is not greatly reduced. .

  According to the second aspect of the present invention, the thickness of the joined portion that joins the plurality of segments that constitute the outer peripheral portion of the honeycomb structure is set, and the plurality of segments that constitute other than the outer peripheral portion of the honeycomb structure are set. It was larger than the thickness of the joined part to be joined. Thereby, the intensity | strength of the segment by the side of an outer peripheral part can further be improved.

  According to the third aspect of the present invention, only the outer peripheral portion of the segment having a small cross-sectional area of the cross section perpendicular to the cell extending direction among the plurality of segments constituting the outer peripheral portion of the honeycomb structure is a thick portion. Was provided. Here, in a honeycomb structure configured as an aggregate of a plurality of segments, a segment having a small cross-sectional area has particularly low strength compared to other segments. By providing the thick portion only on the outer peripheral portion of the segment having such a small cross-sectional area, the strength of the segment on the outer peripheral portion side can be improved without waste.

  According to the fourth aspect of the present invention, the annular structure that is engaged with the thick portion and supports the honeycomb structure on either the upstream side and the downstream side of the honeycomb structure, or the upstream side and the downstream side. A mesh member was provided. Thereby, the honeycomb structure can be supported without blocking the cells.

  According to the fifth aspect of the present invention, the thick part in which the cells are not formed is provided in at least a part of the outer peripheral part of the columnar honeycomb structure. Thereby, the strength of the segment on the outer peripheral portion side can be improved, and the honeycomb structure can be less likely to be cracked or chipped.

  In addition, an annular mesh member for supporting the honeycomb structure was provided by engaging the thick portion so as not to block the cells of the honeycomb structure. This allows exhaust gas to flow evenly into the processed cells and prevents the vibration of the casing from being transmitted directly to the segment via the mesh ring, making it difficult for cracks and chips to occur in the honeycomb structure. can do. Further, for example, even when a crack or a chip occurs in the thick part, no cells are formed in the thick part, so that the collection ability of the exhaust purification filter does not greatly decrease.

[First Embodiment]
Hereinafter, a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is an exploded perspective view showing a configuration of an exhaust purification filter 1 according to the present embodiment.
FIG. 2 is a partial cross-sectional view showing the configuration of the exhaust purification filter 1.
The exhaust purification filter 1 is a filter that is disposed in an exhaust passage of an internal combustion engine and purifies exhaust gas by collecting particulates contained in the exhaust discharged from the internal combustion engine. This exhaust purification filter 1 is particularly preferably used for purification of exhaust discharged from a diesel internal combustion engine, and is hereinafter referred to as “DPF” (Diesel Particulate Filter).

  The DPF 1 includes a columnar honeycomb structure 2, a cylindrical casing 3 in which the honeycomb structure 2 is accommodated, a holding member 4 that fixes the honeycomb structure 2 inside the casing 3, and an upstream side as a net-like member A mesh ring 5 and a downstream mesh ring 6 are included.

FIG. 3 is a top view showing the configuration of the honeycomb structure 2, that is, the honeycomb structure 2 as viewed from the upstream side of the exhaust gas.
The honeycomb structure 2 has a honeycomb shape including a plurality of substantially square cells 22. The honeycomb structure 2 includes a plurality of columnar segments 21 having the plurality of cells 22.

FIG. 4 is a cross-sectional view showing the configuration of the segment 21. In FIG. 4, the left side shows the upstream side of the exhaust gas, and the right side shows the downstream side of the exhaust gas.
The segment 21 includes a plurality of porous walls 23 extending along the direction in which the exhaust gas flows, and a plurality of cells 22 that are partitioned by the porous walls 23 and serve as exhaust gas flow paths. In the following, the direction in which the cells 22 extend is defined as the axial direction of the honeycomb structure 2.

As shown in FIG. 4, the cell 22 is divided into an upstream cell 221 and a downstream cell 222, and the upstream cell 221 and the downstream cell 222 are alternately arranged.
On the downstream side of the upstream cell 221, a downstream seal 242 that prevents exhaust gas from flowing out of the upstream cell 221 to the downstream side of the segment 21 is provided. Further, on the upstream side of the downstream cell 222, an upstream seal 241 that prevents the exhaust gas from flowing from the upstream side of the segment 21 into the downstream cell 222 is provided. The porous wall 23 is formed with a plurality of pores so that exhaust gas can pass through.

  That is, the exhaust gas flowing into the segment 21 first flows into the upstream cell 221, passes through the porous wall 23, flows into the downstream cell 222, and flows out of the segment 21. Here, when the exhaust gas passes through the porous wall 23, the particulates contained in the exhaust gas accumulate on the upstream surface of the porous wall 23 and the holes formed in the porous wall 23.

  As shown in FIG. 3, the honeycomb structure 2 is formed by joining a plurality of segments 21 as described above together at a joining portion 26 and integrating them. Further, a thick portion 25 having a thickness T in which the cells 22 are not formed is provided on the outer peripheral portion of the honeycomb structure 2 over the entire periphery. Such a thick portion 25 is formed by, for example, integrally forming a plurality of segments 21 to form a columnar segment assembly, and then applying a material of the thick portion 25 to the outer peripheral surface of the segment assembly. It is formed by coating with a thickness.

  Here, it is preferable to use a material mainly composed of ceramics for the segment 21, the joint portion 26, and the thick portion 25 constituting the honeycomb structure 2. More specifically, the segment 21, the joining portion 26, and the thick portion 25 are selected from the group including alumina, mullite, lithium aluminum silicate, silicon carbide, silicon nitride, alumina titanate, cordierite, and the like. It is preferable to use seeds or two or more kinds. In order to particularly improve the strength of the honeycomb structure 2, it is preferable to use the same material for the segment 21, the joint portion 26, and the thick portion 25. It may be used.

  Returning to FIGS. 1 and 2, the casing 3 holds the honeycomb structure 2 so that the axial direction of the honeycomb structure 2 coincides with the flow direction of the exhaust gas. The casing 3 is made of, for example, stainless steel or Ni—Cr alloy.

  The holding material 4 has a band shape and is wound along the outer peripheral surface of the honeycomb structure 2. In addition, the holding material 4 is housed in the casing 3 together with the honeycomb structure 2 in a compressed state between the outer peripheral surface of the honeycomb structure 2 and the inner peripheral surface of the casing 3. As the holding material 4, for example, a material formed from heat-resistant fibers such as alumina fibers and mullite fibers is used.

  Each of the upstream mesh ring 5 and the downstream mesh ring 6 has an annular shape, and is engaged with the upstream side and the downstream side of the honeycomb structure 2 to support the honeycomb structure 2 from both ends.

More specifically, each of the mesh rings 5 and 6 has an inner diameter substantially equal to the outer diameter of the honeycomb structure 2 on the honeycomb structure 2 side, and an upstream end portion of the honeycomb structure 2. And the recessed parts 51 and 61 which the edge part of a downstream side latches are formed.
As shown in FIG. 2, when the upstream side of the honeycomb structure 2 is engaged with the concave portion 51 of the upstream mesh ring 5, the upstream mesh ring 5 is located upstream of the outer peripheral surface and the upstream side of the honeycomb structure 2. The honeycomb structure 2 is supported from the upstream side in contact with the two end surfaces.
Further, when the downstream side of the honeycomb structure 2 is locked to the concave portion 61 of the downstream mesh ring 6, the downstream mesh ring 6 is formed between the outer peripheral surface and the downstream end surface on the downstream side of the honeycomb structure 2. The honeycomb structure 2 is supported from the downstream side in contact with the two surfaces.

  Each of these mesh rings 5 and 6 is made of a metal mesh material formed into an annular shape, and can be slightly expanded and contracted. The mesh rings 5 and 6 are accommodated in the casing 3 together with the honeycomb structure 2 in a compressed state between the outer peripheral surface of the honeycomb structure 2 and the inner peripheral surface of the casing 3. For these mesh rings 5 and 6, for example, SUS310 steel or the like is used.

  By using the holding material 4 and the mesh rings 5 and 6 as described above, the honeycomb structure 2 can be stably fixed inside the casing 3.

Next, with reference to FIG. 3 and FIG. 5, the preferable form of the thick part 25 of the honeycomb structure 2 is demonstrated.
FIG. 5 is a partial cross-sectional view showing configurations of the honeycomb structure 2 and the mesh ring 5.

  As described above, the mesh rings 5 and 6 are engaged with the upstream side and the downstream side of the honeycomb structure 2, respectively. When the mesh rings 5 and 6 are locked to the honeycomb structure 2 as described above, the mesh rings 5 and 6 and the meat are so arranged that the plurality of cells 22 of the honeycomb structure 2 are not blocked by the mesh rings 5 and 6. It is necessary to design the dimension of the thick part 25.

  For example, when the length of the mesh ring 5, 6 that is in contact with the upstream end face of the honeycomb structure 2 is W, the thickness T of the thick portion 25 is substantially equal to the length W of the mesh ring 5. It is preferable to design so as to be equal to or slightly smaller than the length W. Thus, the mesh rings 5 and 6 can be locked to the thick portion 25 so as not to block the cells 22 of the honeycomb structure 2.

  As described above, the thickness T of the thick portion 25 can be designed in comparison with the length W of the mesh rings 5 and 6, but can also be designed in comparison with the diameter of the honeycomb structure 2. In this case, as shown in FIG. 3, when the diameter of the portion where the cells 22 are formed in the honeycomb structure 2 is L, the thickness T of the thick portion 25 is 1% or more and 5% or less of the diameter L. It is preferable that By forming the thick portion 25 having such a thickness T, it is possible to secure a surface for engaging the mesh rings 5 and 6 so as not to block the cells 22 of the honeycomb structure 2.

The DPF 1 according to the present embodiment has the following effects.
A thick portion 25 in which the cells 22 are not formed is provided on the outer peripheral portion of the columnar honeycomb structure 2 over the entire periphery. Further, the thickness T of the thick portion 25 is set to be 1% or more and 5% or less with respect to the diameter L of the portion of the honeycomb structure 2 where the cells 22 are formed. Accordingly, by providing the thick portion 25 on the outer peripheral portion of the honeycomb structure 2, the strength of the segment 21 on the outer peripheral portion side can be improved, and the honeycomb structure 2 can be made less likely to be cracked or chipped.

  Further, by providing a thick portion 25 having a thickness T of 1% or more and 5% or less with respect to the diameter L of the portion of the honeycomb structure 2 where the cells 22 are formed, the honeycomb structure 2 is provided with an outer peripheral portion. The mesh rings 5 and 6 can be locked only to the thick portion 25 so as not to block the cell 22 of the body 2. As a result, exhaust gas can be made to flow uniformly into the plurality of processed cells 22, and vibration of the casing 3 is prevented from being directly transmitted to the segment 21 via the mesh rings 5, 6. It can be made difficult to generate cracks and chips. Further, for example, even when a crack or a chip occurs in the thick portion 25, since the cell 22 is not formed in the thick portion 25, the particulate collection ability of the DPF 1 may be greatly reduced. Absent.

[Second Embodiment]
Hereinafter, a second embodiment of the present invention will be described with reference to the drawings.
In the following description of the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 6 is a front view showing a configuration of the honeycomb structure 2A of the DPF 1A according to the present embodiment. As shown in FIG. 6, in the present embodiment, the configuration of the thick portion 25A of the honeycomb structure 2A is different from that of the first embodiment.

  The honeycomb structure 2 </ b> A is formed by joining a plurality of segments to each other by a joining portion 26 and integrating them. Here, in order to form a cylindrical honeycomb structure 2A as an aggregate of a plurality of segments, a plurality of segments 211 constituting the central part of the honeycomb structure 2A and an outer peripheral part of the honeycomb structure 2A are constituted. It is necessary to use a plurality of segments 212 and 213 having different shapes. In particular, the segments 212 and 213 constituting the outer peripheral portion of the honeycomb structure 2A are divided into a segment 212 having a small cross-sectional area perpendicular to the axial direction of the honeycomb structure 2A and a segment 213 having a large cross section.

  As shown in FIG. 6, the thick portion 25A of the present embodiment is provided only on the outer peripheral portion of the segment 212 having a small cross-sectional area among the segments 212 and 213 constituting the outer peripheral portion of the honeycomb structure 2A.

According to the DPF 1A of the present embodiment, in addition to the same effects as the DPF 1 of the first embodiment, the following effects can be obtained.
Of the plurality of segments 212 and 213 constituting the outer peripheral portion of the honeycomb structure 2A, the thick portion 25A is provided only on the outer peripheral portion of the segment 212 having a small cross-sectional area in the cross section perpendicular to the axial direction of the honeycomb structure 2 It was. Here, in the honeycomb structure 2 </ b> A configured as an aggregate of a plurality of segments 211, 212, and 213, the segment 212 having a small cross-sectional area has particularly low strength compared to the other segments 211 and 213. By providing the thick portion 25A only on the outer peripheral portion of the segment 212 having such a small cross-sectional area, the strength of the segment on the outer peripheral portion side can be improved without waste.

[Third Embodiment]
Hereinafter, a third embodiment of the present invention will be described with reference to the drawings.
In the following description of the third embodiment, the same constituent elements as those in the first embodiment are denoted by the same reference numerals, and the description thereof is omitted or simplified.

  FIG. 7 is a front view showing the configuration of the honeycomb structure 2B of the DPF 1B according to the present embodiment. As shown in FIG. 7, in the present embodiment, the configuration of the honeycomb structure 2B is different from that of the first embodiment.

  In the honeycomb structure 2B of the present embodiment, the thickness of the joining portion 261B that joins the plurality of segments 215 constituting the outer peripheral portion of the honeycomb structure 2B is equal to the plurality of segments constituting the central portion of the honeycomb structure 2B. It is larger than the thickness of the joint part 262B that joins 216 together.

According to the DPF 1B of the present embodiment, in addition to the effects exhibited by the DPF 1 of the first embodiment, there are the following effects.
Of the honeycomb structure 2B, the thickness of the joint portion 261B joining the plurality of segments 215 constituting the outer peripheral portion is set to be equal to the thickness of the joint portion 262B joining the plurality of segments 216 constituting the honeycomb structure 2B other than the outer peripheral portion. It was larger than the thickness. Thereby, the intensity | strength of the segment 215 by the side of an outer peripheral part can further be improved.

The present invention is not limited to the embodiment described above, and various modifications can be made.
In the above-described embodiment, the columnar honeycomb structure has been described as an example, but the present invention is not limited to this. For example, the honeycomb structure may have an elliptical or triangular cross section perpendicular to the cell extending direction.

  In the embodiment described above, the mesh rings 5 and 6 are provided on both the upstream side and the downstream side of the honeycomb structure 2, but the present invention is not limited to this. For example, a mesh ring may be provided only on either the upstream side or the downstream side of the honeycomb structure.

  In 1st Embodiment mentioned above, although the thick part 25 was formed over the perimeter of the outer peripheral part of the honeycomb structure 2, it does not restrict to this. For example, like the thick portion 25A of the honeycomb structure 2A of the second embodiment, it may be provided only on a part of the outer peripheral portion of the honeycomb structure.

It is a disassembled perspective view which shows the structure of DPF which concerns on 1st Embodiment of this invention. It is a fragmentary sectional view showing composition of a DPF concerning the above-mentioned embodiment. It is a top view which shows the structure of the honeycomb structure which concerns on the said embodiment. It is sectional drawing which shows the structure of the segment which concerns on the said embodiment. It is a fragmentary sectional view showing composition of a honeycomb structure and a mesh ring concerning the above-mentioned embodiment. It is a top view which shows the structure of the honeycomb structure which concerns on 2nd Embodiment of this invention. It is a top view which shows the structure of the honeycomb structure which concerns on 3rd Embodiment of this invention. It is a fragmentary sectional view which shows the structure of an exhaust gas purification filter. It is a top view which shows the structure of an exhaust gas purification filter. It is a fragmentary sectional view which shows the structure by the side of the edge part of an exhaust gas purification filter.

Explanation of symbols

1,1A, 1B ... DPF (exhaust gas purification filter)
2, 2A, 2B ... honeycomb structure 21, 211, 212, 213, 215, 216 ... segment 22 ... cell 23 ... porous wall 25, 25A ... thick part 26, 261B, 262B ... joined part 5 ... upstream mesh Ring 6 ... Downstream mesh ring

Claims (5)

An exhaust purification filter that is disposed in an exhaust passage of an internal combustion engine and collects particulates discharged from the internal combustion engine,
A plurality of segments having a plurality of cells partitioned by a porous wall;
A columnar honeycomb structure formed by joining the plurality of segments;
A cylindrical casing in which the honeycomb structure is stored;
A holding material that is housed inside the casing in a state wound around the outer periphery of the honeycomb structure, and that fixes the honeycomb structure inside the casing ,
At least a part of the outer peripheral portion of the honeycomb structure is provided with a convex thick portion that is not formed with cells and protrudes in the radial direction when viewed along the extending direction of the cells ,
The exhaust purification filter according to claim 1, wherein a thickness of the thick portion is 1% or more and 5% or less with respect to a diameter of a portion of the honeycomb structure where cells are formed. The honeycomb structure is cylindrical,
The exhaust purification filter according to claim 1, wherein four convex thick portions are provided at equal intervals along a circumferential direction of an outer peripheral portion of the honeycomb structure.   The thick portion is provided only in an outer peripheral portion of a segment having a small cross-sectional area of a cross section perpendicular to a cell extending direction among a plurality of segments constituting the outer peripheral portion of the honeycomb structure. Item 3. The exhaust gas purification filter according to Item 1 or 2.   The upstream side and the downstream side or the upstream side and the downstream side of the honeycomb structure further includes an annular mesh member that is locked to the thick portion and supports the honeycomb structure. The exhaust gas purification filter according to any one of claims 1 to 3. The holding material is a member formed in a belt shape with heat-resistant fibers, and is compressed with the honeycomb structure in a state compressed between the outer peripheral surface of the honeycomb structure and the inner peripheral surface of the casing. The exhaust purification filter according to any one of claims 1 to 4, wherein the exhaust purification filter is housed inside a casing.

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