JP2020075199A - Exhaust gas purification filter, and method for manufacturing the same - Google Patents

Abstract

To provide an exhaust gas purification filter that can improve tradeoff between strength and porosity of partition wall parts, and a method for manufacturing the filter.SOLUTION: An exhaust gas purification filter 1 has a honeycomb structure 11 equipped with an outer wall part 2 which provides a cylindrical shape and partition wall parts 3 which extend along an axial direction of the outer wall part 2 and partition the inside of the outer wall part 2 into a plurality of cylindrical spaces C. The exhaust gas purification filter 1 has: first cells C1 which consist of the cylindrical spaces C closed by a first stopper part 12; and second cells C2 which consist of the cylindrical spaces C closed by second stopper parts 13 and arranged adjacent to the first cells C1. The partition wall parts 3 have: a plurality of first openings 31 which open on the first cell C1 side; and second openings 32 which open on the second cell C2 side. Each first opening 31 is connected to at least one second opening 32 via a communication path 33, and each second opening 32 is connected to at least one first opening 31 via a communication path 33.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an exhaust gas purification filter and a method for manufacturing the same.

  An exhaust gas purifying filter for removing harmful components and particulate matter in exhaust gas is provided in an exhaust pipe of an internal combustion engine such as an automobile engine. The exhaust gas purification filter has a honeycomb structure made of porous ceramics. Inside the honeycomb structure, a large number of cylindrical cells partitioned by partition walls are formed.

  This type of exhaust gas purifying filter has an end on the inlet side of some of the cells and an end on the outlet side of the remaining cells that are open, and the ends of the other cells are closed by plugs. May have a different structure. A cell having an opening on the inlet side and a cell having an opening on the outlet side are arranged adjacent to each other.

  In the exhaust gas purifying filter having such a structure, the exhaust gas flows into the cell having the opening on the inlet side, passes through the pores of the partition wall, and is then discharged from the cell having the opening on the outlet side. The exhaust gas purification filter can remove harmful components and particulate matter contained in the exhaust gas from the exhaust gas when the exhaust gas passes through the pores of the partition wall.

  Conventionally, an exhaust gas purifying filter has a step of producing a honeycomb-shaped molded body including ceramic particles as a raw material of a honeycomb structure, a binder, and water by extrusion molding, a step of firing the molded body, and And a step of closing a predetermined end of the cell with a stopper. For example, Patent Document 1 describes a honeycomb filter including partition walls that form a plurality of cells extending in one direction and a plugging portion that alternately plugs the cells at an end portion.

JP, 2006-95352, A

  In the conventional manufacturing method including Patent Document 1, since the molded body is manufactured by extrusion molding, the arrangement of the ceramic particles and the binder in the molded body cannot be controlled. Therefore, when the molded body is fired, randomly extending pores are formed in the partition wall portion. These pores include bottomed pores, that is, those that are open in either the cell having the opening on the inlet side or the cell having the opening on the outlet side, but not the other.

  Such bottomed pores cannot guide the exhaust gas from the inlet side to the outlet side of the exhaust gas purification filter. Therefore, if the number of bottomed pores increases, there is a possibility that the pressure loss of the exhaust gas purification filter increases and the removal performance of harmful components and the like deteriorates.

  In order to reduce the pressure loss of the exhaust gas purifying filter and improve the performance of removing harmful components and the like, for example, a method of increasing the porosity of the partition wall portion can be considered. In this case, since it is possible to increase the number of pores opened in both the cell opened on the inlet side and the cell opened on the outlet side, reduction of pressure loss and improvement of removal performance of harmful components can be expected. .. However, in this case, the strength of the partition wall may be reduced.

  As described above, in the conventional exhaust gas purifying filter, the strength of the partition wall and the porosity are in a trade-off relationship. Then, in order to further improve the performance of the exhaust gas purifying filter, it is required to improve the trade-off between the strength of the partition wall portion and the porosity.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide an exhaust gas purification filter that can improve the trade-off between the strength of the partition wall and the porosity, and a method for manufacturing the same.

One aspect of the present invention is an outer wall portion (2) having a tubular shape, and a partition wall portion extending along an axial direction of the outer wall portion and partitioning an inner side of the outer wall portion into a plurality of tubular spaces (C). (3) and a honeycomb structure (11) including:
A first plug part (12) closing one end of a part of the cylindrical spaces among the plurality of cylindrical spaces, and a second plug part (13) closing the other end of the remaining cylindrical spaces;
A first cell (C1) composed of the cylindrical space closed by the first plug portion;
The second cell (C2), which is composed of the cylindrical space closed by the second plug portion and is arranged adjacent to the first cell,
The partition wall has a plurality of first openings (31) opened to the first cell side, a second opening (32) opened to the second cell side, the first opening and the second opening. And a communication passage (33, 341, 342, 343, 344, 35, 36, 37, 38, 39) for connection,
Each of the first openings is connected to at least one of the second openings via the communication passage,
Each of the second openings is connected to at least one first opening via the communication passage, and an exhaust gas purification filter (1, 102, 103, 104, 105, 106, 107, 108, 121, 121, 122, 123).

Another aspect of the present invention is a cylindrical outer wall portion (2) and a partition wall extending along the axial direction of the outer wall portion and partitioning the inside of the outer wall portion into a plurality of cylindrical spaces (C). A honeycomb structure (11) including a part (3),
A first plug part (12) closing one end of a part of the cylindrical spaces among the plurality of cylindrical spaces, and a second plug part (13) closing the other end of the remaining cylindrical spaces;
A first cell (C1) composed of the cylindrical space closed by the first plug portion;
The second cell (C2), which is composed of the cylindrical space closed by the second plug portion and is arranged adjacent to the first cell,
The partition wall has a plurality of first openings (31) opened to the first cell side, a second opening (32) opened to the second cell side, the first opening and the second opening. A method of manufacturing an exhaust gas purifying filter, comprising: connecting passages (33, 341, 342, 343, 344, 35, 36, 37, 38, 39) to be connected,
A mold (4, 402) having cavities (S, S2) corresponding to the shape of the honeycomb structure is prepared,
The raw material (110) for the honeycomb structure is filled in the cavity,
An exhaust gas purifying filter manufacturing method comprises heating the raw material together with the mold to burn out the mold and fire the raw material to form the exhaust gas purifying filter.

  The exhaust gas purifying filter has a plurality of first openings opened on the side of the first cell and a second opening opened on the side of the second cell in a partition wall partitioning the first cell and the second cell. And a communication passage that connects the first opening and the second opening. Further, each first opening is connected to at least one second opening via a communication passage, and each second opening is connected to at least one first opening via a communication passage. There is.

  That is, the exhaust gas purifying filter does not have a bottomed hole-like fine hole through which exhaust gas cannot flow. Therefore, when the exhaust gas purifying filter has the same porosity as that of the conventional exhaust gas purifying filter, the partition wall portion can be increased in strength because it does not have bottomed pores. Further, when the exhaust gas purifying filter has a partition wall strength that is similar to that of a conventional exhaust gas purifying filter, the porosity can be increased because it does not have bottomed pores.

  Therefore, according to the exhaust gas purifying filter, the trade-off between the strength of the partition wall and the porosity can be improved. As a result, the exhaust gas purification filter can reduce the pressure loss while improving the performance of purifying harmful substances and the like while ensuring the same strength of the partition wall as that of the conventional one. Further, it is possible to further increase the strength of the partition wall portion while ensuring the same level of pressure loss and performance of removing harmful components.

  In the manufacturing method of the above aspect, a mold having a cavity corresponding to the shape of the honeycomb structure is used, and the raw material of the honeycomb structure filled in the mold is fired together with the mold. Therefore, by previously providing the mold with a structure corresponding to the communication passage, the communication passage having a desired shape can be accurately formed. As a result, it is possible to easily manufacture the exhaust gas purifying filter having no bottomed pores as described above.

As described above, according to the above aspect, it is possible to provide the exhaust gas purification filter and the manufacturing method thereof, which can improve the trade-off between the strength of the partition wall and the porosity.
In addition, the reference numerals in parentheses described in the claims and the means for solving the problems indicate the correspondence with the specific means described in the embodiments described later, and limit the technical scope of the present invention. Not a thing.

FIG. 1 is a perspective view of an exhaust gas purification filter according to the first embodiment. FIG. 2 is a cross-sectional view showing a main part of the exhaust gas purification filter according to the first embodiment. FIG. 3 is an enlarged view of the partition wall portion in FIG. FIG. 4 is a sectional view showing a main part of a mold used for producing the exhaust gas purifying filter of the first embodiment. FIG. 5 is an enlarged view of a portion corresponding to the partition wall portion in FIG. FIG. 6 is a cross-sectional view showing a main part of the mold of Embodiment 1 in which the raw material is filled. FIG. 7 is a cross-sectional view showing an essential part of an exhaust gas purification filter in which the first plug portion and the second plug portion are integrally formed with the outer wall portion and the partition wall portion in the second embodiment. FIG. 8 is a sectional view showing a main part of a mold used for producing the exhaust gas purifying filter of the second embodiment. FIG. 9 is a partially enlarged cross-sectional view showing a partition wall portion of an exhaust gas purification filter including a communication passage having no bottomed hole according to the third embodiment. FIG. 10 is an example of another aspect of the communication passage having no bottomed hole in the third embodiment. FIG. 11 is an example of another aspect of the communication passage having no bottomed hole in the third embodiment. FIG. 12 is an example of still another mode of the communication passage having no bottomed hole in the third embodiment. FIG. 13 is a plan view of a partition wall portion of an exhaust gas purification filter having a communication passage provided with a connection portion as viewed from the first cell side in the fourth embodiment. 14 is a sectional view taken along the line XIV-XIV of FIG. 15 is a sectional view taken along the line XV-XV of FIG. FIG. 16 is a partial cross-sectional view of an exhaust gas purification filter showing another aspect of the communication passage provided with the connection portion in the fifth embodiment. 17 is a sectional view taken along the line XVII-XVII of FIG. FIG. 18 is a partial cross-sectional view showing one mode of a communication passage having a plurality of connecting portions on the path from the first opening to the second opening in the sixth embodiment. FIG. 19 is a partial cross-sectional view showing another aspect of the communication passage having a plurality of connecting portions on the path from the first opening to the second opening in the sixth embodiment. FIG. 20 is a partial cross-sectional view showing still another aspect of the communication passage having a plurality of connecting portions on the path from the first opening to the second opening in the sixth embodiment. FIG. 21 is a partially enlarged cross-sectional view showing a main part of a conventional exhaust gas purification filter in a comparative form.

(Embodiment 1)
Embodiments of the exhaust gas purification filter and the method for manufacturing the same will be described with reference to FIGS. As shown in FIGS. 1 and 2, the exhaust gas purification filter 1 is provided with a tubular outer wall portion 2 and an axially extending outer wall portion 2, and the inner wall of the outer wall portion 2 has a plurality of tubular spaces C. The honeycomb structure 11 is provided with the partition walls 3 that are partitioned into. As shown in FIG. 2, one end of a part of the tubular spaces C among the plurality of tubular spaces C is closed by the first plug portion 12, and the other end of the remaining tubular space C is the second plug portion. It is closed by 13.

  Further, as shown in FIG. 2, the exhaust gas purifying filter 1 includes a first cell C1 formed of a cylindrical space C closed by a first plug portion 12 and a cylindrical space C closed by a second plug portion 13. And a second cell C2 arranged adjacent to the first cell C1.

  As shown in FIG. 3, the partition wall portion 3 includes a plurality of first openings 31 opened on the first cell C1 side, a second opening 32 opened on the second cell C2 side, a first opening 31 and a second opening. And a communication passage 33 that connects 32 to each other. Each first opening 31 is connected to at least one second opening 32 via a communication passage 33, and each second opening 32 is connected to at least one first opening 32 via the communication passage 33. It is connected to the opening 31.

  Hereinafter, an example of the configuration of the exhaust gas purification filter 1 will be described in more detail. The exhaust gas purification filter 1 of this embodiment has a columnar shape as shown in FIG. The exhaust gas purifying filter 1 is configured so that even if the exhaust gas is introduced from either of the two end faces 14 and 15, the exhaust gas can be discharged to the opposite end faces 15 and 14. Has been done. Hereinafter, for convenience, one end surface 14 of the exhaust gas purification filter 1 is referred to as a “first end surface 14”, and the other end surface 15 is referred to as a “second end surface 15”. The shape of the exhaust gas purification filter 1 is not limited to the shape of this embodiment, and can be set as appropriate according to the shape of the exhaust pipe of the internal combustion engine.

  The honeycomb structure 11 in the exhaust gas purification filter 1 has an outer wall portion 2 having a tubular shape and a partition wall portion 3 partitioning the inner side of the outer wall portion 2, and the inner wall of the outer wall portion 2 is divided by the partition wall portion 3 into a plurality. Is divided into a cylindrical space C. The form of the cylindrical space C is not particularly limited. For example, the tubular space C may have a polygonal cross-sectional shape such as a square shape, a pentagonal shape, and a hexagonal shape in a cross section perpendicular to the axial direction of the outer wall portion 2.

  Further, all of the plurality of tubular spaces C may have the same cross-sectional shape, or some of the tubular spaces C may have different cross-sectional shapes from the other tubular spaces C. Good. Furthermore, the cross-sectional areas of all the tubular spaces C in the cross section perpendicular to the axial direction of the outer wall portion 2 may be the same, or the cross-sectional areas of some of the tubular spaces C may be the same as those of other tubular spaces C. It may be different from the area.

  As shown in FIG. 1, in the exhaust gas purifying filter 1 of the present embodiment, the inner side of the outer wall portion 2 is partitioned by the partition wall portions 3 arranged in a grid pattern. Each of the cylindrical spaces C has a quadrangular cross-sectional shape in a cross section perpendicular to the axial direction of the outer wall portion 2.

The honeycomb structure 11 may be made of ceramic, for example. As the ceramic, for example, cordierite composed of 45 to 55% by mass of SiO ₂ , 33 to 42% by mass of Al ₂ O ₃ , and 12 to 18% by mass of MgO, silicon carbide, silicon-silicon carbide system is used. A composite material, mullite, alumina, spinel, a silicon carbide-cordierite composite material, lithium aluminum silicate, aluminum titanate, or the like can be adopted. Among these, the honeycomb structure 11 is preferably made of cordierite having a small thermal expansion coefficient and excellent thermal shock resistance.

  Further, the honeycomb structure 11 may carry a catalyst containing a noble metal such as platinum, palladium, or rhodium. In this case, the exhaust gas purification filter 1 can remove harmful components such as hydrocarbons, carbon monoxide, and nitrogen oxides together with the particulate matter in the exhaust gas.

  As shown in FIGS. 1 and 2, the plurality of cylindrical spaces C are configured as either the first cell C1 or the second cell C2. As shown in FIG. 2, the first cell C1 has a bottomed hole shape that is open to the second end surface 15 and has the first end surface 14 closed by the first plug portion 12. The second cell C2 has a bottomed hole shape that is open to the first end surface 14 and has the second end surface 15 closed by the second plug portion 13. The first cell C1 and the second cell C2 are arranged adjacent to each other with the partition wall 3 interposed therebetween.

  The first plug portion 12 and the second plug portion 13 may be made of, for example, ceramic. As the ceramic, similar to the honeycomb structure 11, cordierite, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, aluminum titanate, etc. Can be adopted.

  The formation of the first plug portion 12 and the second plug portion 13 may be performed at the same time when the honeycomb structure 11 is manufactured, or the first plug portion 12 and the second plug portion 13 are formed after the honeycomb structure 11 is manufactured. You can also do it. The first plug portion 12 and the second plug portion 13 in this embodiment are formed after the honeycomb structure 11 is manufactured.

  As shown in FIG. 3, the partition walls 3 partitioning the first cells C1 and the second cells C2 include a plurality of first openings 31 opened on the first cell C1 side and a plurality of first openings 31 opened on the second cell C2 side. The second opening 32 and the communication path 33 connecting the first opening 31 and the second opening 32. Each first opening 31 is connected to one or more second openings 32 via a communication passage 33, and each second opening 32 is connected to one or more first openings 31 via the communication passage 33. It is connected to the. In the present embodiment, one first opening 31 and one second opening 32 are connected via a communication passage 33.

  Each first opening 31 in the exhaust gas purification filter 1 of the present embodiment is connected to one second opening 32, and each second opening 32 is connected to one first opening 31. Therefore, the partition wall portion 3 of the present embodiment does not have a bottomed hole-shaped pore that does not allow exhaust gas to pass through either the surface on the first cell C1 side or the surface on the second cell C2 side. Therefore, when the exhaust gas purifying filter 1 has the same porosity as that of the conventional exhaust gas purifying filter, the partition wall portion 3 can be increased in strength because it does not have bottomed pores. Further, when the exhaust gas purifying filter 1 has the strength of the partition wall portion 3 similar to that of the conventional exhaust gas purifying filter 1, the porosity can be increased because it does not have bottomed pores.

  As described above, according to the exhaust gas purification filter 1, it is possible to improve the trade-off between the strength of the partition wall portion 3 and the porosity.

  The aspect of the manufacturing method of the exhaust gas purification filter 1 of the present embodiment is exemplified below. First, as shown in FIGS. 4 and 5, a mold 4 having a cavity S corresponding to the shape of the honeycomb structure 11 is prepared. Next, as shown in FIG. 6, the raw material 110 of the honeycomb structure 11 is filled in the cavity S of the mold 4. Then, by heating the raw material 110 together with the mold 4, the mold 4 is burned off and the raw material 110 is fired to form the honeycomb structure 11.

  The mold 4 is made of a material that burns off at a temperature lower than the firing temperature of the raw material 110. For example, the material of the mold 4 may be resin.

  The template 4 can be produced by, for example, a layered manufacturing method, that is, a method of stacking layered partial structures to form a desired shape. As the layered modeling method, for example, an optical modeling method of forming a layered partial structure by irradiating a liquid photocurable resin with light to locally cure the resin, or a powder of a mold 4 spread in a layered manner. It is possible to employ a method such as a powder method in which the layered partial structure is formed by locally melting or adhering.

  In this embodiment, as shown in FIG. 4, the mold 4 includes a frame body portion 41 arranged on the outer periphery of the cavity S, and a columnar portion 42 continuous with the frame body portion 41 and having a prismatic shape corresponding to the cylindrical space C. And have. Further, as shown in FIG. 5, a thin line portion 43 is arranged in the gap between the columnar portions 42. The frame portion 41 has one or more filling ports 44 that are continuous with the cavity S and open to the external space.

  The end of the thin wire portion 43 is connected to one of the columnar portions 42. That is, the thin line portion 43 has a shape corresponding to a portion of the communication passage 33 excluding the bottomed hole 331 (see FIG. 3) branched from the path connecting the first opening 31 and the second opening 32. .. More specifically, the thin line portion 43 in this aspect extends along a straight line connecting the first opening 31 and the second opening 32.

  In this embodiment, the raw material 110 of the honeycomb structure 11 is injected from the filling port 44 of the mold 4 to fill the hollow S of the mold 4 with the raw material 110 of the honeycomb structure 11 as shown in FIG. You can As the raw material 110 of the exhaust gas purification filter 1, for example, a powder of an inorganic component prepared so that the composition after firing is a desired composition, or a slurry obtained by dispersing the powder of the inorganic component in a solvent such as water is used. can do.

  The raw material 110 does not need to contain a binder. In the conventional manufacturing method, a binder is usually added to the raw material 110 in order to maintain the shape of the molded body from the time of extrusion molding to the time of firing. On the other hand, in the manufacturing method of this aspect, since the raw material 110 in the cavity S can be held by the mold 4, the exhaust gas purification filter 1 having a desired shape can be obtained without adding a binder.

  Further, when the binder is not contained, dimensional shrinkage during firing due to disappearance of the binder can be suppressed. Further, it is possible to suppress the formation of unintended pores in the partition wall portion 3 due to the thermal decomposition gas generated from the binder. As a result, the exhaust gas purifying filter 1 having desired dimensions and characteristics can be manufactured more easily.

  In this way, after the raw material 110 of the exhaust gas purification filter 1 is filled in the mold 4, the raw material 110 is heated together with the mold 4. Since the template 4 burns off at a temperature lower than the firing temperature of the raw material 110, the template 4 disappears when the firing is completed and the honeycomb structure 11 is formed. Therefore, by heating the raw material 110 together with the mold 4, the honeycomb structure 11 can be obtained.

  Then, the raw material of the 1st stopper part 12 and the 2nd stopper part 13 is arrange | positioned at the one end or the other end of the cylindrical space C in the honeycomb structure 11 using a dispenser etc. (illustration omitted). Then, in this state, the honeycomb structure 11 is heated again and the first plug portion 12 and the second plug portion 13 are fired, whereby the exhaust gas purification filter 1 can be obtained.

  In the embodiment described above, when the honeycomb structure 11 is fired, the pyrolysis gas is generated due to the burning of the mold 4. When this pyrolyzed gas stays in the gap between the mold 4 and the raw material 110, for example, as shown in FIG. 3, the communication path 33 has a bottom with a branch from the path from the first opening 31 to the second opening 32. Holes 331 may be formed. Although not shown in the drawing, in some cases, the partition wall 3 may have pores opened only on the first cell C1 side or pores opened only on the second cell C2 side.

  The determination as to whether or not the partition wall portion 3 has pores opened only on the first cell C1 side and pores opened only on the second cell C2 side may be performed as follows. That is, the exhaust gas purifying filter 1 is photographed by computer tomography to obtain a reconstructed image of the exhaust gas purifying filter 1.

  Five observation regions are randomly set on the partition 3 existing in the reconstructed image. Each observation region has a quadrangular prism shape extending in the entire thickness direction of the partition wall portion 3, has an end face facing the first cell C1 or the second cell C2, and having a square shape with a side of 200 μm. It is determined whether or not there are pores opened only on the first cell C1 side and pores opened only on the second cell C2 side in these observation regions. When there are no pores opened only on the first cell C1 side and no pores opened only on the second cell C2 side in the five observation regions, the partition wall portion 3 is the first cell C1. It is determined that there is no pore opened only on the side and the second cell C2 side.

  Further, the determination as to whether or not the communication passage 33 has the bottomed hole 331 branched from the path from the first opening 31 to the second opening 32 can also be performed by the same method as the above-described determination. That is, the exhaust gas purifying filter 1 is photographed by computer tomography to obtain a reconstructed image of the exhaust gas purifying filter 1.

  In the partition wall portion 3 existing in this reconstructed image, the five observation regions having the above-described square pillar shape are randomly set. It is determined whether or not the bottomed hole 331 exists in these observation areas. When the bottomed holes 331 do not exist in the five observation areas, it is determined that the partition wall portion 3 does not have the bottomed holes 331.

  In the manufacturing method of the above-described aspect, the number of pores and bottomed holes 331 that cannot pass the gas formed due to manufacturing is determined by the number of pores in the exhaust gas purification filter manufactured by the conventional manufacturing method. And the number is significantly smaller than the number of bottomed holes 331. Therefore, such a pore or a bottomed hole 331 has a small adverse effect on the trade-off between the strength and the porosity of the partition wall portion 3.

(Embodiment 2)
In the present embodiment, as shown in FIG. 7, an exhaust gas purification filter 102 in which the first plug portion 12 and the second plug portion 13 are integrally formed with the outer wall portion 2 and the partition wall portion 3 will be described. In addition, among the reference numerals used in the present embodiment and thereafter, the same reference numerals as those used in the already-explained embodiment represent the same components as those in the already-explained embodiment unless otherwise specified.

  In the exhaust gas purification filter 102 of this embodiment, the outer wall portion 2, the partition wall portion 3, the first plug portion 12 and the second plug portion 13 are integrally formed. Here, the state in which the first plug portion 12 and the second plug portion 13 are “integrally formed” with the outer wall portion 2 and the partition wall portion 3 means that the first plug portion 12 and the second plug portion 13 and the outer wall portion. 2 and the partition wall 3 have no difference in material and the like, and there is no boundary between them.

  The exhaust gas purification filter 102 of the present embodiment includes, for example, as shown in FIG. 8, a cavity S2 corresponding to a shape in which the honeycomb structure 11, the first plug portion 12 and the second plug portion 13 are integrated. It can be manufactured by the same method as in Embodiment 1 except that the mold 402 is used. Others are the same as those in the first embodiment.

  As in the present embodiment, the first plug portion 12 and the second plug portion 13 are integrated with the honeycomb structure 11, whereby the honeycomb structure 11 is manufactured and the first plug portion 12 and the second plug portion 13 form a cylinder. The work of closing the space C can be performed in the same step. As a result, it is possible to avoid an increase in the number of steps and further improve the productivity of the exhaust gas purification filter 102. In addition, the exhaust gas purification filter 102 of the present embodiment can exhibit the same operational effects as those of the first embodiment.

(Embodiment 3)
In the present embodiment, as shown in FIGS. 9 to 12, communication passages 341 to 344 having no bottomed holes 331 (see FIG. 3) branched from the path from the first opening 31 to the second opening 32 are provided. The exhaust gas purification filters 103 to 106 will be described.

  As in the exhaust gas purification filter 103 shown in FIG. 9, when one first opening 31 and one second opening 32 are connected via the communication passage 341, the communication passage 341 is There is no branch on the path from the opening 31 to the second opening 32.

  The mode of connection between the first opening 31 and the second opening 32 is not limited to the mode shown in FIG. 9. For example, like the exhaust gas purifying filter 104 shown in FIG. 10, a plurality of first openings 31 and one second opening 32 may be connected via a communication passage 342, or the exhaust gas shown in FIG. Like the purification filter 105, the first opening 31 at one place and the plurality of second openings 32 may be connected via the communication passage 343.

  Further, like the exhaust gas purification filter 106 shown in FIG. 12, the plurality of first openings 31 and the plurality of second openings 32 may be connected via the communication passage 344. When the communication passage is branched on the path from the first opening 31 to the second opening 32 like the communication passages 341 to 343, the branch destination is either the first opening 31 or the second opening 32. It is connected to the.

  The partition wall portion may have only one type of these communication passages 341 to 344, or may have two or more types. Others are the same as those in the first embodiment.

  As in the present embodiment, by providing the communication passages 341 to 344 having no bottomed hole 331 on the path from the first opening 31 to the second opening 32, the exhaust gas stays in the bottomed hole 331 on the path. Can be avoided. As a result, the effect of improving the trade-off between the strength of the partition 3 and the porosity can be further enhanced.

(Embodiment 4)
In the present embodiment, as shown in FIG. 14, a first communicating portion 351 extending from the first opening 31, a connecting portion 352 connecting the plurality of first communicating portions 351 to each other, and a connecting portion 352 to a second portion. The exhaust gas purification filter 107 having the communication passage 35 including the second communication portion 353 extending to the opening 32 side will be described.

  As shown in FIGS. 13 and 14, the partition wall portion 3 of the exhaust gas purifying filter 107 of the present embodiment has a plurality of first openings 31 arranged on the wall surface of the first cell C1 side and spaced from each other. It has an opening group 310. As shown in FIG. 13, the partition wall portion 3 has a plurality of first opening groups 310, and the first opening groups 310 are arranged at intervals. The arrangement of the first opening group 310 is not limited to the arrangement of this embodiment.

  The 1st opening 31 which comprises the 1st opening group 310 is arrange | positioned so that it may show a hexagon in planar view seen from the 1st cell C1 side in the thickness direction of the partition part 3. The arrangement of the first openings 31 included in each first opening group 310 is not limited to the arrangement of this embodiment. For example, the first openings 31 included in each first opening group 310 have a shape such as a circle, an oval, an ellipse, or a polygon in a plan view viewed from the first cell C1 side in the thickness direction of the partition wall portion 3. It may be arranged to present. In addition, the first openings 31 included in each first opening group 310 may be randomly arranged.

  As shown in FIG. 14, the first communication portion 351 extends from the first opening 31 to the connection portion 352. The arrangement and shape of the first communication portion 351 are not particularly limited. For example, the first communication portion 351 of the present embodiment extends from the first opening 31 in a direction parallel to the thickness direction of the partition wall portion 3. In addition, the cross-sectional shape of the first communication portion 351 in the cross section orthogonal to the thickness direction of the partition wall portion 3 is circular. The cross-sectional shape of the first communication portion 351 is not limited to this embodiment, and may have various shapes such as an ellipse, an oval, and a polygon.

  The partition wall portion 3 has a second opening group 320 including a plurality of second openings 32 arranged at intervals on the wall surface on the second cell C2 side. The partition part 3 has a plurality of second opening groups 320, and the second opening groups 320 are arranged at intervals. The arrangement of the second opening group 320 of this embodiment is the same as the arrangement of the first opening group 310. The arrangement of the second opening group 320 is not limited to the arrangement of this embodiment.

  Although not shown in the drawing, the second openings 32 forming the second opening group 320 have a hexagonal shape in a plan view seen from the second cell side in the thickness direction of the partition wall portion 3 as in the first opening group 310. Are arranged to exhibit. Note that the arrangement of the second openings 32 included in each second opening group 320 is not limited to the arrangement of this embodiment, and various aspects can be adopted like the first openings 31.

  As shown in FIG. 14, the second opening 32 of this embodiment is directly connected to the second communication portion 353. That is, the second communication portion 353 extends from the second opening 32 to the connection portion 352. The second communicating portion 353 may be extended from the connecting portion 352 and directly connected to the second opening 32 as in the present embodiment, or may be between the second communicating portion 353 and the second opening 32. It may be connected to the second opening 32 via another connecting portion and a communicating portion provided on the.

  The arrangement and shape of the second communicating portion 353 are not particularly limited. For example, the second communication portion 353 of this embodiment extends from the connection portion 352 in a direction parallel to the thickness direction of the partition wall portion 3. Further, the cross-sectional shape of the second communication portion 353 in the cross section orthogonal to the thickness direction of the partition wall portion 3 is circular. The cross-sectional shape of the second communication portion 353 is not limited to this embodiment, and may have various shapes such as an ellipse, an oval, and a polygon. Others are the same as those in the first embodiment.

  The exhaust gas purification filter 107 of the present embodiment has a plurality of connecting portions 352 arranged inside the partition wall portion 3. A plurality of first communication portions 351 extending from the first openings 31 included in the first opening group 310 are connected to each connection portion 352. In addition, a plurality of second communication portions 353 extends from each connection portion 352 toward the second opening 32.

  The number, arrangement and shape of the connecting portions 352 can take various aspects. For example, as shown in FIG. 15, the connecting portion 352 of this embodiment has a circular shape in a cross section orthogonal to the thickness direction of the partition wall portion 3. The connecting portion 352 may be a straight line, an ellipse, an ellipse, a polygon, or the like in a cross section orthogonal to the thickness direction. Further, in the present embodiment, some of the first communication portions 351 of the plurality of first communication portions 351 are connected to the individual connection portions 352, but all the first communication portions 351 have a single connection. It may be connected to the section 352.

  As shown in FIG. 14, the connection part 352 has a first connection port 354 that is an open end of the first communication part 351 and a second connection port 355 that is an open end of the second communication part 353. There is. The second connection port 355 of this embodiment is arranged so as to face the first connection port 354.

  By providing the connection portion 352 in the communication passage 35 as in the present embodiment, the exhaust gas that has flowed in from either the first communication portion 351 or the second communication portion 353 can be diffused in the connection portion 352. As a result, the exhaust gas can be brought into contact with the inner surface of the communication passage 35 more efficiently, and the effect of removing harmful components and particulate matter in the exhaust gas can be further enhanced.

  Further, as shown in FIGS. 14 and 15, the connection portion 352 of the present embodiment has the first communication portion 351 arranged on the outermost side of the first communication portion 351 and the second communication portion 353 which are continuous with the connection portion 352. Further, it has an extending portion 356 extending outward from the second communication portion 353. The extension part 356 can disturb the flow of the exhaust gas flowing from either the first communication part 351 or the second communication part 353 and can stir the exhaust gas. Therefore, the exhaust gas purification filter 107 of the present embodiment can bring the exhaust gas into contact with the inner surface of the communication passage 35 more efficiently by stirring the exhaust gas at the connection portion 352. As a result, the effect of removing harmful components and particulate matter in the exhaust gas can be further enhanced.

  The exhaust gas purification filter 107 of the present embodiment has the same effects as those of the first embodiment in addition to the effect of providing the connecting portion 352 and the effect of providing the extending portion 356 in the connecting portion 352 described above. it can.

(Embodiment 5)
In this embodiment, another mode of arrangement of the first connection port 364 and the second connection port 365 will be described. As shown in FIG. 16, the partition wall portion 3 of the exhaust gas purification filter 108 of the present embodiment has a communication passage 36 including a first communication portion 361, a connection portion 362, and a second communication portion 363. The connection part 362 has a first connection port 364 that is an open end of the first communication part 361, a second connection port 365 that is an open end of the second communication part 363, and an extension part 366. .. Then, as shown in FIGS. 16 and 17, a part of the first connection port 364 and a part of the second connection port 365 are arranged to face each other. That is, the first connection port 364 of the present embodiment is arranged so that a part thereof faces the second connection port 365 and the remaining part faces the inner surface of the connection part 362. Similarly, the second connection port 365 is arranged so that a part thereof faces the first connection port 364 and the remaining part faces the inner surface of the connection part 352. Others are the same as in the fourth embodiment.

  As described above, the second connection port 365 of the present embodiment is arranged at a position slightly displaced from the front surface of the first connection port 364. Similarly, the first connection port 364 is arranged at a position slightly displaced from the front surface of the second connection port 365. By arranging the first connection port 364 and the second connection port 365 as described above, a part of the exhaust gas flowing into the connection portion 362 from either the first connection port 364 or the second connection port 365 is connected. The flow of exhaust gas can be disturbed by hitting the inner surface of the portion 362. Therefore, the exhaust gas purifying filter 108 of the present embodiment can stir the exhaust gas at the connection portion 362 and can effectively bring the exhaust gas into contact with the inner surface of the communication passage 36.

  Further, in the exhaust gas purification filter 108 of the present embodiment, as shown in FIG. 16, a part of the communication passage 36 is arranged along a straight line connecting the first opening 31 and the second opening 32. That is, the partition wall portion 3 has a through hole 367 formed of a part of the communication passage 36 as shown in FIG. 17 in a plan view when viewed from the thickness direction. Therefore, a part of the exhaust gas flowing into the communication passage 36 from either the first opening 31 or the second opening 32 is guided to the other through the through hole 367 and discharged to the outside of the communication passage 36. You can Therefore, the exhaust gas purification filter 108 of the present embodiment can reduce the pressure loss due to the turbulence of the exhaust gas flow in the communication passage 36.

  As described above, the exhaust gas purifying filter 108 of the present embodiment stirs the exhaust gas in the connecting portion 352 while reducing the pressure loss by the through hole 367, and is more effective in removing harmful components and particulate matter in the exhaust gas. Can be removed. In addition, the exhaust gas purification filter 108 of the present embodiment can achieve the same effects as those of the fourth embodiment.

(Embodiment 6)
In this embodiment, as shown in FIGS. 18 to 20, communication paths 37, 38, 39 having a plurality of connecting portions 372, 382, 392 are provided on the path from the first opening 31 to the second opening 32. The exhaust gas purification filters 121, 122, 123 will be described.

  The number and arrangement of the connecting portions 372, 382, 392 can take various forms. For example, the exhaust gas purification filters 121 to 123 shown in FIGS. 18 to 20 have four connecting portions 372 (372a to 372d) and 382 (382a to 382d) on the path from the first opening 31 to the second opening 32. , 392 (392a to 392d). Further, the adjacent connecting portions 372, 382, 392 on each path are connected via a plurality of communicating portions 371 (371a to 371e), 382 (382a to 382e), 392 (392a to 392e). Note that the number of the connecting portions 372, 382, 392 is not limited to the aspect of this embodiment, and can be changed as appropriate depending on desired characteristics.

  Further, the connecting portions 372, 382, 392 of this embodiment have extending portions 376, 386, 396.

  In the following, for convenience, the first connecting portion 372a, 382a, 392a, the second connecting portion 372b, 382b, 392b, and the third connecting portion 372, 382, 392 will be described in order from the connecting portion closest to the first opening 31. The connecting portions 372c, 382c, 392c and the fourth connecting portions 372d, 382d, 392d are referred to as. Further, the communication portions that connect the first opening 31 and the first connection portions 372a, 382a, 392a are referred to as first communication portions 371a, 381a, 391a. Hereinafter, the second communication portions 371b, 381b, 391b, the third communication portions 371c, 381c, 391c, the fourth communication portions 371d, 381d, 391d, and the fifth communication portions 371e, 381e, 391e are referred to in the order of being closer to the first opening 31. ..

  That is, the second communicating portions 371b, 381b, 391b connect the first connecting portions 372a, 382a, 392a and the second connecting portions 372b, 382b, 392b, and the third communicating portions 371c, 381c, 391c are the second connecting portions. The connection portions 372b, 382b, 392b are connected to the third connection portions 372c, 382c, 392c, and the fourth communication portions 371d, 381d, 391d are the third connection portions 372c, 382c, 392c and the fourth connection portion 372d, 382d and 392d are connected, and the fifth communication portions 371e, 381e, and 391e connect the fourth connection portion and the second opening 32.

  For example, like the exhaust gas purification filter 121 shown in FIG. 18, the first communication part 371a to the fifth communication part 371e may be extended in a direction parallel to the thickness direction of the partition wall part 3. Further, like the exhaust gas purifying filter 123 shown in FIG. 20, the first communication portion 391a to the fifth communication portion 391e may be extended in a direction inclined with respect to the thickness direction of the partition wall portion 3.

  Further, as shown in FIG. 18, the first communication portion 371a to the fifth communication portion 371e are located at the same position in a plan view viewed from a direction parallel to a straight line connecting the first opening 31 and the second opening 32. It may be arranged.

  In the first connecting portion 372a shown in FIG. 18, the opening of the first communicating portion 371a is arranged in front of the opening of the second communicating portion 371b. Similarly, in the second connecting portion 372b, the opening of the second communicating portion 371b is arranged in front of the opening of the third communicating portion 371c, and in the third connecting portion 372c, the opening of the third communicating portion 371c is the fourth. It is arranged in front of the communication part 371d, and in the fourth connection part 372d, the opening of the fourth communication part 371d is arranged in front of the fifth communication part 371e.

  As in the exhaust gas purifying filter 122 shown in FIG. 19, in each of the connecting portions 382a to 382d, a part of the opening of the communicating portion 381 connected to the first opening 31 side and the communicating portion connected to the second opening 32 side. It is preferably arranged so as to face a part of the opening of 381. That is, in the first connecting portion 382a, it is preferable that a part of the opening of the first communicating portion 381a is arranged at a position facing a part of the opening of the second communicating portion 381b. Similarly, in the second connecting portion 382b, it is preferable that a part of the opening of the second communicating portion 381b is arranged at a position facing a part of the opening of the third communicating portion 381c, and in the third connecting portion 382c. It is preferable that a part of the opening of the third communication part 381c is arranged at a position facing a part of the opening of the fourth communication part 381d, and the opening of the fourth communication part 381d is formed in the fourth connection part 382d. It is preferable that a part thereof is arranged at a position facing a part of the opening of the fifth communication portion 381e.

  Thus, in each connection portion 382, a part of the opening of the communication portion 381 connected to the first opening 31 side and a part of the opening of the communication portion 381 connected to the second opening 32 side face each other. In such a case, the exhaust gas can be stirred in each connection portion 382 to more effectively remove harmful components and particulate matter in the exhaust gas.

  Further, a part of the communication passage 38 shown in FIG. 19 is arranged along a straight line connecting the first opening 31 and the second opening 32. More specifically, in the exhaust gas purification filter 122, the first communication portion 381a, the third communication portion 381c, and the fifth communication portion 381e are parallel to a straight line connecting the first opening 31 and the second opening 32, That is, they are arranged on the same straight line in the thickness direction of the partition wall portion 3. Further, the second communication portion 381b and the fourth communication portion 381d are on the same straight line in the thickness direction of the partition wall portion 3, and are different from the first communication portion 381a, the third communication portion 381c, and the fifth communication portion 381e. It is located in a position. Thereby, in a plan view viewed from the thickness direction of the partition wall portion 3, the through hole 387 is formed in a region where the first communication portion 381a to the fifth communication portion 381e and the first connection portion 382a to the fourth connection portion 382d overlap. There is.

  As described above, the partition wall portion 3 of the exhaust gas purification filter 122 has the through hole 387 formed of a part of the communication passage 38 in a plan view viewed from a direction parallel to the straight line connecting the first opening 31 and the second opening 32. Have Therefore, the exhaust gas purification filter 122 can further reduce the pressure loss while exhibiting the above-described effects.

  By providing a plurality of connecting portions 372, 382, 392 in the communication passages 37, 38, 39 as in the present embodiment, the exhaust gas is agitated in each of the connecting portions 372, 382, 392, and the inner surface of the communication passage is more efficiently Can make good contact. As a result, the effect of removing harmful components and particulate matter in the exhaust gas can be further enhanced. In addition, the exhaust gas purification filter of this embodiment can achieve the same effects as those of the fourth embodiment.

  In order to confirm the action and effect of the exhaust gas purifying filter of this embodiment, a simulation was performed as follows. First, a structural model of the exhaust gas purifying filter 121 shown in FIG. 18 and a structural model of the exhaust gas purifying filter 122 shown in FIG. 19 were produced. In addition, in these structural models, the diameters of the communicating portions 371 and 381 were 2 μm, and the diameters of the connecting portions 372 and 382 were 13.5 μm. Further, the number of communicating portions 371, 381 connected to each connecting portion 372, 382 was set to 19. The porosity of these structural models, that is, the ratio of the volume of the communication passages 37 and 38 to the volume of the partition wall portion 3 including the communication passages 37 and 38 was 70%.

  For comparison with these structural models, as shown in FIG. 9, a structural model in which the first opening 31 and the second opening 32 were connected via a linear communication path 341 was produced. The diameter of the communication passage 341 in this structural model was 13.5 μm. Further, the number of communication passages 341 was appropriately set so that the porosity of the structural model was 70%.

  The collection rate of the particulate matter when the exhaust gas containing the particulate matter was passed through these three structural models was calculated. As a result, the collection rate in the structural model shown in FIG. 18 is 6.1 times the collection rate in the structural model shown in FIG. 9, and the collection rate in the structural model shown in FIG. It was 6.7 times the collection rate.

  From these results, by providing the connecting portions 372 and 382 on the path from the first opening 31 to the second opening like the communication passages 37 and 38, the harmful components and particulate matter in the exhaust gas can be more effective. Understand that it can be removed. In addition, as shown in FIG. 19, in each connection portion 382, a part of the opening of the communication portion 381 connected to the first opening 31 side and the opening of the communication portion 381 connected to the second opening 32 side. In the case where they are arranged so as to face each other, as shown in FIG. 18, the opening of the communication part 371 connected to the first opening 31 side is connected to the communication part 371 connected to the second opening 32 side. It can be understood that the effect of removing harmful components and particulate matter in the exhaust gas can be further enhanced as compared with the case of being arranged in front of the opening.

(Comparative form 1)
In this embodiment, the structure of the exhaust gas purification filter 9 manufactured by the conventional manufacturing method will be described. The conventional exhaust gas purifying filter 9 prepares a kneaded material containing ceramic particles 91 as a raw material of the exhaust gas purifying filter 9 and a binder, and then forms a kneaded material compact by extrusion molding and sinters the compact. It is produced by

  In the conventional manufacturing method, the ceramic particles 91 existing in the molded body are randomly arranged. Therefore, as shown in an example in FIG. 21, pores 93 that are randomly extended from the gaps between the ceramic particles 91 are formed in the partition wall portion 92 after sintering. Then, these pores 93 include pores having a bottom, that is, pores 931 opened on only one surface of the partition wall portion 92.

  Therefore, in the conventional exhaust gas purification filter 9, when the porosity is the same, the exhaust gas purification filters 1, 102 to 106 of Embodiments 1 to 3 are exhausted by the amount of the pores 931 through which the exhaust gas cannot flow. Gas flow rate is reduced. As a result, pressure loss may increase. Further, when the pressure loss is the same, the conventional exhaust gas purification filter 9 has a porosity higher than that of the exhaust gas purification filters 1 and 102 to 106 of Embodiments 1 to 3 by the amount of the pores 931 through which the exhaust gas cannot flow. Becomes higher. As a result, the strength of the partition wall portion 92 may be reduced.

  The present invention is not limited to the above-described embodiments, and can be applied to various embodiments without departing from the spirit of the invention.

1, 102-106, 121-123 Exhaust gas purifying filter 11 Honeycomb structure 2 Outer wall part 3 Partition part 31 1st opening 32 2nd opening 33, 341-344, 35-39 Communication path C Cylindrical space C1 1st cell C2 2nd cell

Claims (7)

An outer wall portion (2) having a tubular shape, and a partition wall portion (3) extending along an axial direction of the outer wall portion and partitioning an inner side of the outer wall portion into a plurality of tubular spaces (C). A honeycomb structure (11),
A first plug part (12) closing one end of a part of the cylindrical spaces among the plurality of cylindrical spaces, and a second plug part (13) closing the other end of the remaining cylindrical spaces;
A first cell (C1) composed of the cylindrical space closed by the first plug portion;
The second cell (C2), which is composed of the cylindrical space closed by the second plug portion and is arranged adjacent to the first cell,
The partition wall has a plurality of first openings (31) opened to the first cell side, a second opening (32) opened to the second cell side, the first opening and the second opening. And a communication passage (33, 341, 342, 343, 344, 35, 36, 37, 38, 39) for connection,
Each of the first openings is connected to at least one of the second openings via the communication passage,
Each of the second openings is connected to at least one first opening via the communication passage, and an exhaust gas purification filter (1, 102, 103, 104, 105, 106, 107, 108, 121, 121, 122, 123).   The exhaust gas purification filter (1) according to claim 1, wherein each of the communication passages (341, 342, 343, 344) does not have a bottomed hole (331) branched from a path from the first opening to the second opening. 103, 104, 105, 106).   The communication passages (35, 36, 37, 38, 39) include a first communication portion (351, 361, 371a, 381a, 391a) extending from the first opening and a plurality of the first communication portions. A connecting portion (352, 362, 372a, 382a, 392a) connecting to each other, and a second communicating portion (353, 363, 371b, 381b, 391b) extended from the connecting portion to the second opening side, An exhaust gas purification filter (107, 108, 121, 122, 123) according to claim 1 or 2, which has.   The connection part has a first connection port (364) which is an open end of the first communication part and a second connection port (365) which is an open end of the second communication part, and The exhaust gas purification filter (108, 122) according to claim 3, wherein a part of the first connection port and a part of the second connection port are arranged to face each other.   The connecting portion extends outwardly beyond the outermost communicating portion (351a, 353a, 361a, 363a) of the first communicating portion and the second communicating portion that are connected to the connecting portion. The exhaust gas purification filter (107, 108, 121, 122, 123) according to claim 3 or 4, which has a portion (356, 366, 376, 386, 396). An outer wall portion (2) having a tubular shape, and a partition wall portion (3) extending along an axial direction of the outer wall portion and partitioning an inner side of the outer wall portion into a plurality of tubular spaces (C). A honeycomb structure (11),
A first plug part (12) closing one end of a part of the cylindrical spaces among the plurality of cylindrical spaces, and a second plug part (13) closing the other end of the remaining cylindrical spaces;
A first cell (C1) composed of the cylindrical space closed by the first plug portion;
The second cell (C2), which is composed of the cylindrical space closed by the second plug portion and is arranged adjacent to the first cell,
The partition wall has a plurality of first openings (31) opened to the first cell side, a second opening (32) opened to the second cell side, the first opening and the second opening. A method of manufacturing an exhaust gas purifying filter, comprising: connecting passages (33, 341, 342, 343, 344, 35, 36, 37, 38, 39) to be connected,
A mold (4, 402) having cavities (S, S2) corresponding to the shape of the honeycomb structure is prepared,
The raw material (110) for the honeycomb structure is filled in the cavity,
A method of manufacturing an exhaust gas purification filter, comprising heating the raw material together with the mold to burn out the mold and fire the raw material to form the exhaust gas purification filter.   The method for manufacturing an exhaust gas purification filter according to claim 6, wherein the mold is manufactured by a layered manufacturing method.

Images