JP2015157730A - honeycomb structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a honeycomb structure that has good collection efficiency and suppresses an increase in pressure loss when ash is accumulated.SOLUTION: A honeycomb structure 100 comprises a honeycomb substrate 10 having partition walls 1 partitioning and forming a cell 2 extending an inflow end surface 11 to an outflow end surface 12, and sealing parts 25. The honeycomb structure 100 includes at least one set of cell groups 5 comprising three cells consisting of a both ends sealed cell 2b, an inlet cell 2a neighboring the both ends sealed cell 2b, and an outlet cell 2c neighboring the both ends sealed cell 2b. The partition wall 1 that partitions and forms the both ends sealed cell 2b has: a first common partition wall 1a which is a common partition wall 1 partitioning and forming both the inlet cell 2a and the both ends sealed cell 2b; and a second common partition wall 1b which is a common partition wall 1 partitioning and forming both the outlet cell 2c and the both ends sealed cell 2b. A first circulation hole 7 is formed at an outflow end surface 12 side end part of the first common partition wall 1a, and a second circulation hole 8 is formed at an inflow end surface 11 side end part of the second common partition wall 1b.

Description

  The present invention relates to a honeycomb structure. More specifically, the present invention relates to a honeycomb structure having a good collection efficiency and suppressing an increase in pressure loss when ash is accumulated.

  Conventionally, an exhaust gas purification apparatus provided with a honeycomb structure filter (honeycomb structure) to purify exhaust gas by removing particulates (hereinafter also referred to as PM (Particulate Matter)) contained in exhaust gas discharged from various engines or the like Is used. The honeycomb structure is disposed in a honeycomb base material having a honeycomb structure, an opening portion on an outflow end face side of an inlet cell which is a predetermined cell of the honeycomb base material, and an opening portion on an inflow end face of an outlet cell which is a remaining cell. What is provided with the plugging part is known (for example, refer patent document 1, 2). Specifically, the honeycomb base material has porous partition walls that partition and form a plurality of cells serving as exhaust gas flow paths.

  In the honeycomb structure, when exhaust gas containing fine particles is introduced from the inflow end portion side which is one end portion, the fine particles are filtered by the partition walls, and the purified gas is discharged from the outflow end portion side which is the other end portion. . In this way, the honeycomb structure purifies the exhaust gas.

  When exhaust gas flows into the inlet cell of the honeycomb structure, the inlet cell is plugged at the opening on the outflow end face side, so that the exhaust gas passes through the partition wall that defines the inlet cell and flows into the outlet cell. . And since the exit cell is plugged in the opening part at the inflow end face side, the purified gas is discharged from the opening part at the outflow end face side. The PM accumulated inside the honeycomb structure is burned by raising the temperature of the exhaust gas at appropriate intervals or heating it with an electric heater or the like. In this way, PM is prevented from accumulating too much inside the honeycomb structure.

  Moreover, as a honeycomb structure, in order to prevent an increase in pressure loss, a structure in which plugging portions are provided only at one end portion or the other end portion has been reported (for example, Patent Document 3). , 4).

JP 49-38266 A JP 56-148607 A JP 2003-35126 A JP 2004-108203 A

  However, the honeycomb structures described in Patent Documents 1 and 2 have a large increase in pressure loss because one or the other of the cell openings is plugged. Moreover, when the ash (ash) which is incombustible content contained in PM accumulates, the accumulated ash is hard to be discharged | emitted from a honeycomb structure. Therefore, the increase in pressure loss when ash accumulates is also large. Since the honeycomb structure described in Patent Document 3 has cells in which no plugging portions are disposed, ash accumulation is less than that of the honeycomb structures described in Patent Documents 1 and 2, and pressure loss is reduced. Although the increase is small, the PM collection efficiency is low. As in the case of Patent Document 3, the honeycomb structure described in Patent Document 4 has a cell in which no plugging portions are arranged, so that the increase in pressure loss is small. The PM collection efficiency is lower than that of the honeycomb structure. Further, in the honeycomb structure described in Patent Document 4, since the plugging portion is disposed on the outflow end portion side of the cell, ash is easily deposited on the outflow end portion of the honeycomb structure. Is difficult to be discharged. Therefore, the pressure loss increases unless the accumulated ash is discharged. On the other hand, it takes time to discharge ash.

  For these reasons, it has been desired to develop a honeycomb structure that has good collection efficiency and suppresses an increase in pressure loss when ash is accumulated.

  The present invention has been made in view of such problems of the prior art. An object of the present invention is to provide a honeycomb structure having good collection efficiency and suppressing increase in pressure loss when ash is accumulated.

  According to the present invention, the following honeycomb structure is provided.

[1] A honeycomb substrate having partition walls that form a plurality of cells that form a flow path of fluid and extend from an inflow end surface that is one end surface into which the fluid flows in to an outflow end surface that is the other end surface from which the fluid flows out; A plugging portion disposed in the opening of the cell of the honeycomb base material, wherein the plurality of cells are arranged in both the inflow end surface side and the outflow end surface side. The both-end plugged cells provided, the inlet cell adjacent to the both-end plugged cells, and the plugged portion disposed only in the opening on the outflow end face side, and adjacent to the both-end plugged cells The both-end plugged cells comprising at least one set of three cell groups, each including an outlet cell in which the plugging portion is disposed only in the opening on the inflow end face side, and constituting the cell group The partition wall forming the partition is formed by sealing the inlet cell and the both-end plugged cell. A first common partition that is a common partition that partitions both the first and second partitions, and a second common partition that is a common partition that partitions both the outlet cell and the plugged cells at both ends. The first common partition wall is formed with a first flow hole at the end portion on the outflow end surface side, and the second common partition wall is formed with a second flow hole at the end portion on the inflow end surface side. Structure.

[2] In a cross section orthogonal to the cell extending direction of the honeycomb substrate, a first center that is the center of the inlet cell, a second center that is the center of the plugged cells at both ends, and the center of the outlet cell The honeycomb structure according to [1], wherein the inlet cell, the both-end plugged cells, and the outlet cell are arranged so that the third center is located on the same straight line.

[3] In the cross section perpendicular to the cell extending direction of the honeycomb base material, the inlet cells, the both-end plugged cells, and the outlet cells constituting one cell group are L-shaped. The honeycomb structure according to [1], which is disposed in

[4] The opening area of the first flow hole is 0.3 to 3.5 times the average cross-sectional area of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group. The honeycomb structure according to any one of [1] to [3].

[5] The opening area of the second flow hole is 0.3 to 3.5 times the average cross-sectional area of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group. The honeycomb structure according to any one of [1] to [4].

[6] The honeycomb structure according to any one of [1] to [5], which is made of a porous ceramic.

[7] The honeycomb structure according to any one of [1] to [6], wherein the honeycomb base material is integrally formed.

[8] The honeycomb structure according to any one of [1] to [6], wherein the honeycomb base material has a segment structure including a plurality of honeycomb segments.

  The honeycomb structure of the present invention has a collection efficiency comparable to that of a conventional honeycomb structure. That is, the honeycomb structure of the present invention has good collection efficiency. Further, the honeycomb structure of the present invention has a cell group composed of three specific cells, and the first flow hole and the second flow hole are formed in a predetermined partition wall. That is, in the honeycomb structure of the present invention, there are two spaces where ash accumulates, that is, the end portion on the outflow end surface side and the end portion on the inflow end surface side (see symbols X and Y in FIG. 2). Further, in the honeycomb structure of the present invention, the ash accumulated inside the honeycomb structure is appropriately carried on the flow of the exhaust gas and discharged to the outside according to the route of the inlet cell, the both end plugged cells, and the outlet cell. Therefore, in the honeycomb structure of the present invention, an increase in pressure loss when ash is accumulated is suppressed. As a result, the number of maintenance operations when ash is accumulated is small, and the maintenance operations need not be performed. In other words, it is so-called maintenance-free for ash accumulation.

1 is a perspective view schematically showing an embodiment of a honeycomb structure of the present invention. Fig. 3 is a cross-sectional view schematically showing a cross section parallel to the cell extending direction in one embodiment of the honeycomb structure of the present invention. FIG. 3 is an enlarged view schematically showing an enlarged part of a cross section orthogonal to the cross section shown in FIG. 2. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 3 is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. It is explanatory drawing which shows typically the manufacturing process of one Embodiment of the honeycomb structure of this invention. It is explanatory drawing which shows typically the manufacturing process of one Embodiment of the honeycomb structure of this invention. It is explanatory drawing which shows typically the manufacturing process of one Embodiment of the honeycomb structure of this invention.

  Embodiments of the present invention will be described below. The present invention is not limited to the following embodiments, and appropriate modifications and improvements are added to the following embodiments on the basis of ordinary knowledge of those skilled in the art without departing from the spirit of the present invention. It should be understood that what has been described also falls within the scope of the invention.

[1] Honeycomb structure:
One embodiment of the honeycomb structure of the present invention is a honeycomb structure 100 shown in FIG. The honeycomb structure 100 includes a honeycomb base material 10 having partition walls 1 for partitioning and forming a plurality of cells 2, and a plugging portion 25 disposed in the opening of the cells 2 of the honeycomb base material 10. Yes. The partition wall 1 serves as a fluid flow path and defines a plurality of cells 2 extending from an inflow end surface 11 that is one end surface into which fluid flows in to an outflow end surface 12 that is the other end surface from which fluid flows out. The plurality of cells 2 are adjacent to the both-end plugged cells 2b in which the plugged portions 25 are disposed in the openings on both the inflow end face 11 side and the outflow end face 12 side, At least one set of the cell group 5 which consists of three cells of the entrance cell 2a and the exit cell 2c is included. The inlet cell 2a is adjacent to the plugged cells 2b at both ends, and the plugged portion 25 is disposed only at the opening on the outflow end face 12 side. The outlet cell 2c is adjacent to the both-end plugged cell 2b, and the plugged portion 25 is disposed only in the opening on the inflow end face 11 side. That is, the inlet cell 2a and the outlet cell 2c are adjacent to one double-sided plugged cell 2b. A partition wall 1 that partitions both end plugged cells 2b constituting the cell group 5 includes a first common partition wall 1a and a second common partition wall 1b. The first common partition wall 1a is a common partition wall 1 that partitions both the inlet cell 2a and the both end plugged cells 2b. The second common partition wall 1b is a common partition wall 1 that partitions both the outlet cell 2c and the both-end plugged cells 2b. A first flow hole 7 is formed at the end of the first common partition wall 1a on the outflow end surface 12 side, and a second flow hole 8 is formed at the end of the second common partition wall 1b on the inflow end surface 11 side. Yes.

  The honeycomb structure 100 shown in FIGS. 1 and 2 has no through-cells that are cells that are not plugged (that is, cells in which both openings are open). It can prevent that collection efficiency falls. That is, it is possible to obtain better collection efficiency than a honeycomb structure in which one or the other of the cell openings is plugged (honeycomb structures as shown in Patent Documents 3 and 4).

  Further, in the honeycomb structure 100, an increase in pressure loss when ash is accumulated is suppressed. As a result, the honeycomb structure 100 has a small number of maintenance operations when ash is accumulated, and the maintenance work may be hardly performed. That is, the honeycomb structure 100 is so-called maintenance-free with respect to ash accumulation. Specifically, in the honeycomb structure 100, the ash is an end portion on the outflow end face 12 side (in FIG. 2) of the flow path formed by the normal path of the inlet cell 2a, the both-end plugged cell 2b, and the outlet cell 2c. , And the end portion on the inflow end face 11 side (indicated by “Y” in FIG. 2). On the other hand, in the conventional honeycomb structure (honeycomb structure as shown in Patent Document 1), ash is easily deposited only at the end portion on the outflow end face side. That is, the honeycomb structure 100 has a wide space in which ash can be deposited. Therefore, the honeycomb structure 100 has a pressure loss as compared with the conventional honeycomb structure even when the same amount of ash that can be deposited under a predetermined condition in the conventional honeycomb structure is accumulated in the honeycomb structure. The degree of increase is small. Furthermore, the ash accumulated in the honeycomb structure 100 is appropriately discharged along with the flow of exhaust gas. For example, ash present in the inlet cell 2a flows into the plugged cells 2b from the first flow holes 7 formed in the partition wall 1 between the inlet cell 2a and the plugged cells 2b. Next, the ash flows into the outlet cell 2c from the second flow hole 8 formed in the partition wall 1 between the both-end plugged cell 2b and the outlet cell 2c. Thereafter, the honeycomb structure 100 is discharged. As described above, the space in which the ash can be stored is wide, and the accumulated ash is appropriately discharged along with the flow of the exhaust gas, so that the flow path of the exhaust gas is not completely blocked, and the ash is accumulated. As a result, the degree of increase in pressure loss is reduced (increase in pressure loss is suppressed).

  FIG. 1 is a perspective view schematically showing one embodiment of a honeycomb structure of the present invention. FIG. 2 is a cross-sectional view schematically showing a cross section parallel to the cell extending direction in one embodiment of the honeycomb structure of the present invention.

  The inlet cell, the both-end plugged cell, and the outlet cell are preferably arranged as follows. That is, in the cross section perpendicular to the cell extending direction of the honeycomb substrate, the center of the inlet cell is the “first center”, the center of the plugged cells at both ends is the “second center”, and the center of the outlet cell is “the first center”. 3 centers ". At this time, it is preferable that the inlet cell, the both-end plugged cell, and the outlet cell are arranged so that the first center, the second center, and the third center are located on the same straight line. In the honeycomb structure 100, the inlet cell 2a, both-end plugged cells 2b, and the outlet cell 2c are the center of the inlet cell 2a (first center), the center of the both-end plugged cells 2b (second center), and the outlet. The centers (third centers) of the cells 2c are arranged on the same straight line.

  Moreover, when the said cell is seen from the cell extension direction, the inlet cell, the both end plugged cells, and the outlet cell may be arranged so as to form an L shape as shown in FIGS. 4A to 4H. This is a preferred embodiment. That is, it is also a preferable aspect that the cell group composed of three cells, one inlet cell, one end-sealed cell, and one outlet cell, is L-shaped as a whole.

  “The inlet cell, the plugged cell at both ends, and the outlet cell are L-shaped” does not mean that the first common partition wall and the second common partition wall are opposed to each other. Each cell is arranged so as to be in a position where two adjacent partition walls are formed.

  FIG. 4A is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4B is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4C is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4D is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4E is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4F is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4G is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention. FIG. 4H is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention.

  The honeycomb structure of the present invention may include at least one set of cell groups. That is, the honeycomb structure of the present invention may partially include a cell group including three cells each including an inlet cell, a both-end plugged cell, and an outlet cell. Even when the cell group partially exists, the effect of the present invention can be expected. When the cell group is partially present, for example, the cell group is arranged in the center part of the honeycomb structure (the central part in the cross section perpendicular to the cell extending direction), and the outer peripheral part (the part other than the center part) is The cell (through cell or conventional type cell) may be arranged. That is, the outer peripheral portion of the honeycomb structure has cells that do not have plugged portions at both ends (through cells), or the plugged portions are staggered at both end surfaces, only the inflow end surface, or only the outflow end surface. A cell (conventional type cell) can be arranged. The latter cell (conventional type cell) is a cell in which plugging portions are arranged like a conventional type honeycomb structure. Further, the above arrangement may be reversed between the center portion and the outer peripheral portion of the honeycomb structure. In the honeycomb structure of the present invention, the “cell group ratio” may be appropriately determined in consideration of the required collection efficiency and pressure loss. It is preferably 10 to 100%, and more preferably 30 to 100%. The “cell group ratio” is the ratio of “number of cell groups” to “the value of 1/3 of the total number of cells (the number of all cells regardless of the presence or absence of plugging portions)”. Note that cells that are deformed by the outer peripheral wall or that have one or more sides (walls) forming the cell as the outer peripheral wall (hereinafter sometimes referred to as “incomplete cells”) are excluded. count.

  When a plurality of cell groups are included, the arrangement pattern of these cell groups is not particularly limited. For example, the plurality of cell groups can be arranged as shown in FIGS. 5A to 11D. In FIG. 5A to FIG. 11D, “1” indicates an entrance cell. “2” indicates a plugged cell at both ends. “3” indicates an exit cell. 5A to 11D schematically show the arrangement pattern of the cell group. For convenience of explaining the arrangement pattern of the cell group, a part of the honeycomb structure is extracted and shown. Moreover, description is abbreviate | omitted about the plugging part in FIG. 5A-FIG. 11D.

  Each of FIGS. 5A to 11D is a plan view schematically showing an example of an array pattern of cell groups in the honeycomb structure of the present invention.

  5A and 5B show an example in which a cell group in which an inlet cell, both-end plugged cells, and an outlet cell are arranged on the same straight line is arranged in the same order. FIGS. 6A and 6B show an example in which the arrays shown in FIGS. 5A and 5B are shifted by one cell for each column (on the left or right side of the figure, or on the upper or lower side of the figure). 7A, FIG. 7B, and FIG. 8 show an example in which the number of cells to be shifted for each column (on the left or right side in the figure) is changed based on the arrangement shown in FIG. 5A. 9 and 10 show an example in which the cell groups shown in FIGS. 4A, 4B, and 4E are alternately arranged.

  Moreover, in the honeycomb structure of the present invention, as shown in FIGS. 11A to 11D, a cell group in which the inlet cells, the plugged cells at both ends, and the outlet cells are arranged on the same straight line is reduced to 1/2. You may arrange | position by shifting by the horizontal direction of a figure for every cell (the left side or the right side of a figure).

  5A to FIG. 8 and FIG. 11A to FIG. 11D, FIG. 5A and FIG. 5B are manufactured so that the inlet cell, the both-end plugged cell, and the outlet cell are in a straight line, so that the plugged portion can be easily formed. Is easy.

  In FIG. 6A, FIG. 6B, and FIG. 8, since all four partition walls of the inlet cell are adjacent to the both-side plugged cells or the outlet cells, the exhaust gas also flows through these partition walls. Therefore, in the arrangements (array patterns) shown in FIGS. 6A, 6B, and 8, the pressure loss is about 5% lower than other array patterns.

  5A to 11D may be combined and arranged in combination.

  The opening area of the first flow hole is preferably 0.3 to 3.5 times the average value of the cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group, It is more preferable that it is ˜3 times. If the “opening area of the first flow hole” is less than the lower limit, the pressure loss may increase. If the “opening area of the first flow hole” exceeds the upper limit, the iso-strength may be reduced. “Cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell” refer to the area of each cell in a cross section orthogonal to the cell extending direction. In this specification, “the average value of the cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group” refers to the following values. That is, the average value is 1/3 of the sum of the “cross-sectional area of the inlet cell”, the “cross-sectional area of the plugged cells at both ends”, and the “cross-sectional area of the outlet cell” constituting one cell group. It is a value obtained by multiplying. When calculating the opening area, a plurality of cell groups are selected as appropriate.

  Specifically, the “end portion on the outflow end face side” where the first flow hole is formed is from the outflow end face of the honeycomb structure to a position that is 1/3 of the length in the cell extending direction of the honeycomb structure. It is a portion (first flow hole forming region). The first flow hole is preferably formed in the first flow hole formation region. Among the first flow hole formation region, the length of the honeycomb structure cell in the extending direction from the outflow end surface of the honeycomb structure is also included. More preferably, it is formed in a portion up to 1/5 position.

  The opening area of the second flow hole is preferably 0.3 to 3.5 times the average value of the cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group, It is more preferable that it is ˜3 times. If the “opening area of the second flow hole” is less than the lower limit, the pressure loss may increase. If the “opening area of the second flow hole” exceeds the upper limit, the iso strength may be reduced.

  Specifically, the “end portion on the inflow end face side” where the second flow hole is formed is from the inflow end face of the honeycomb structure to a position that is 1/3 of the length in the cell extending direction of the honeycomb structure. It is a portion (second flow hole forming region). The second flow hole is preferably formed in the second flow hole formation region, but among the second flow hole formation region, the length in the direction in which the cells of the honeycomb structure extend from the inflow end surface of the honeycomb structure. More preferably, it is formed in a portion up to 1/5 position.

  The shape of each opening of the first and second flow holes is not particularly limited, and the shape of the opening of each flow hole may be the same or different. Examples of the shape of the opening of each flow hole include a circular shape, a semi-circular shape, an elliptical shape, a semi-elliptical shape (a shape obtained by cutting an ellipse with a short diameter), a triangular shape, and a rectangular shape. FIG. 3 shows the first flow hole 7 in an enlarged manner, and the shape of the opening of the first flow hole 7 is a semi-elliptical shape. Thus, an opening having a semi-elliptical shape is easy to form. FIG. 3 is an enlarged view schematically showing an enlarged part of a cross section orthogonal to the cross section shown in FIG. 2.

  The honeycomb structure of the present invention is preferably made of a porous ceramic. That is, it is preferable that the honeycomb substrate and the plugging portion constituting the honeycomb structure are made of a porous ceramic. Thus, if it consists of porous ceramics, it will be easy to carry | support a catalyst. The honeycomb structure of the present invention may be made of sintered metal or metal foil obtained by sintering metal powder after forming.

  When made of ceramic, specifically, cordierite, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, aluminum titanate, silicon nitride, and silicon carbide-corge from the viewpoint of excellent strength and heat resistance. More preferred is at least one selected from the group consisting of light composite materials. Among these, cordierite and silicon carbide are preferable.

  The honeycomb substrate of the honeycomb structure of the present invention preferably has a segment structure composed of a plurality of honeycomb segments. By having such a segment structure, it is possible to manufacture a product that is difficult to manufacture integrally (for example, a large product).

  Specifically, the honeycomb substrate having the segment structure can be a bonded body having a plurality of honeycomb segments and a bonding layer that bonds the plurality of honeycomb segments to each other.

  In addition, the honeycomb base material of the honeycomb structure of the present invention is preferably integrally formed. Thus, the manufacturing process is simplified by being integrally formed. “Integrally molded” means that the honeycomb substrate is composed of one member. That is, the whole honeycomb substrate is formed at once by a method such as extrusion.

  Each member of the honeycomb structure of the present invention will be further described below.

[1-1] Honeycomb substrate:
The thickness of the partition walls of the honeycomb substrate 10 is preferably 40 to 600 μm, more preferably 80 to 500 μm, and particularly preferably 100 to 400 μm. If the partition wall thickness is less than 40 μm, the partition wall strength may be insufficient. On the other hand, if it exceeds 600 μm, the pressure loss may increase.

  The porosity of the partition walls of the honeycomb substrate 10 is preferably 25 to 80%, more preferably 30 to 75%, and particularly preferably 30 to 70%. If the porosity is less than 25%, pressure loss may increase. On the other hand, if it exceeds 80%, the strength of the partition may be lowered. Here, in this specification, “porosity” is a value measured with a mercury porosimeter.

  The average pore diameter of the partition walls of the honeycomb substrate 10 is preferably 5 to 100 μm, more preferably 7 to 80 μm, and particularly preferably 7 to 60 μm. There exists a possibility that a pressure loss may increase that the said average pore diameter is less than 5 micrometers. On the other hand, if it exceeds 100 μm, the exhaust gas purification performance may be reduced. Here, the “average pore diameter” in the present specification is a value measured with a mercury porosimeter.

The cell density of the honeycomb substrate 10 is preferably 12 to 200 cells / cm ² , more preferably 15 to 150 cells / cm ² , and particularly preferably 20 to 120 cells / cm ² . If the cell density is less than 12 cells / cm ² , the iso strength may be reduced. On the other hand, if it exceeds 200 cells / cm ² , the pressure loss may increase.

  The shape of the cell 2 in the cross section orthogonal to the extending direction of the cell 2 of the honeycomb substrate 10 can be a square shape, a hexagonal shape, or the like.

  The length of the honeycomb substrate 10 (honeycomb structure 100) in the cell extending direction can be 50 to 1000 mm or more (over 1000 mm). Moreover, when the end surface of the honeycomb structure 100 is circular, the diameter of the end surface can be 25 to 600 mm or more (over 600 mm).

  The shape of the honeycomb substrate 10 can be an arbitrary shape such as a cylindrical shape, an elliptical column shape, a quadrangular column shape, or a hexagonal column shape. Among these, a cylindrical shape and a quadrangular prism shape are preferable.

[1-2] Plugging portion:
The depth of the plugging portion (the length in the cell extending direction) is preferably 0.3 to 10 mm, more preferably 0.5 to 8 mm, and particularly preferably 1 to 7 mm. . If the depth of the plugged portion is less than the above lower limit value, the plugged portion may easily fall off due to vibration or the like. When the depth of the plugged portion is more than the above upper limit value, when used as a filter, there is a possibility that the portion functioning as a filter is reduced.

  The material of the plugging portion can be the same as that of the partition wall. In particular, the material of the plugging portion is preferably a porous ceramic.

  Although the honeycomb structure 100 shown in FIG. 1 has the outer peripheral wall 26, the outer peripheral wall 26 may not be provided. The outer peripheral wall 26 can be formed by applying a peripheral coating material to the outer periphery of the honeycomb structure with a ceramic material. In the case where the honeycomb base material is integrally formed by extrusion molding or the like, the outer peripheral wall 26 may be formed simultaneously with the partition walls in the process of manufacturing the honeycomb base material 10.

[2] Manufacturing method of honeycomb structure:
The honeycomb structure of the present invention can be manufactured as follows, for example. A honeycomb structure in which the honeycomb base material is integrally formed will be described.

  First, a kneaded material for preparing a honeycomb base material is prepared, and this kneaded material is formed to prepare a honeycomb formed body (forming step).

  Next, the obtained honeycomb formed body (or the dried honeycomb dried body as necessary) is fired to produce a honeycomb fired body (honeycomb fired body producing step).

  Next, as shown in FIG. 12A, the manufactured honeycomb fired body 50 is arranged with the end on the outflow end face 112 side facing upward. Thereafter, the resin member is pushed into the partition wall 3 forming the first flow hole. Thereafter, the honeycomb fired body 50 is inverted and disposed with the end on the inflow end surface 111 side facing upward. Thereafter, as shown in FIG. 12B, the resin member 20 is pushed into the partition wall 3 forming the second flow hole. By pushing the resin member 20, the portion of the partition wall 3 into which the resin member 20 is pushed is destroyed. In addition, since the partition 3 is very thin, the resin member 20 can be pushed in by human power. By using the resin member in this way, it is possible to reliably form a desired size of flow holes (first flow hole, second flow hole). In other words, when the resin member serves as a spacer and the resin member disappears by firing, flow holes (first flow hole, second flow hole) are formed.

  The physical properties of the resin member are not particularly limited as long as it functions as a spacer and disappears upon firing. The resin member may be hard enough to break a part of the partition wall. In addition, when destroying a partition, you may carry out separately using a needle | hook, a laser beam, etc., without pushing in a resin member directly. In this case, the hardness of the resin member can be set freely and does not have to be hard enough to break the partition wall.

  Specifically, a polyethylene member, a nylon member, or the like can be used as the resin member.

  Next, as shown in FIG. 12C, the plugged material 23 is filled into the space formed by pushing the resin member 20 of the honeycomb fired body 50 into which the resin member 20 is pushed (plugging material filling step). .

  In the method for manufacturing a honeycomb structure of the present invention, a method that does not use a resin member may be employed. That is, by increasing the viscosity of the plugging material, a portion that becomes a flow hole when the plugging material is filled may not be blocked by the plugging material.

  Next, the honeycomb fired body filled with the plugging material is fired again to form a plugged portion (plugged portion forming step). The resin member disappears by this baking, and the portion where the resin member is disposed becomes the first flow hole and the second flow hole. In this way, a honeycomb structure can be manufactured.

  Also, the partition walls of the dried honeycomb body dried after forming are ground or burned off with a laser beam to form flow holes of a desired size so that the portions that become the flow holes are not blocked. The honeycomb structure may be fabricated by firing after filling with the stop material.

  EXAMPLES Hereinafter, although this invention is demonstrated concretely based on an Example, this invention is not limited to these Examples.

Example 1
A pore former, an organic binder and water were added to the cordierite forming raw material to obtain a molding raw material. The forming raw materials were mixed and kneaded to prepare a cylindrical clay. As an organic binder, methylcellulose was used and 5 mass parts was added with respect to 100 mass parts of cordierite forming raw materials. Water was added as a dispersion medium and added so as to be 10% by mass with respect to the entire forming raw material. The cordierite raw material is a raw material that becomes cordierite by firing. Specifically, the chemical composition is such that silica (SiO ₂ ) is in the range of 42 to 56 mass%, alumina (Al ₂ O ₃ ) is in the range of 30 to 45 mass%, and magnesia (MgO) is in the range of 12 to 16 mass%. Is a ceramic raw material mixed with “predetermined raw material”. The “predetermined raw material” is a raw material selected from talc, kaolin, calcined kaolin, alumina, aluminum hydroxide, and silica.

  Next, the kneaded material was extruded using a predetermined die, and a honeycomb formed body having partition walls that partitioned a plurality of cells and an outer peripheral wall that was integrally extruded simultaneously with the partition walls was obtained. The honeycomb formed body had a square cell shape (a cell shape in a cross section perpendicular to the cell extending direction) and a cylindrical shape as a whole.

  Next, the obtained honeycomb formed body was dried by dielectric drying and hot air drying, and then fired at a maximum temperature of 1420 ° C. for 100 hours to prepare a honeycomb fired body.

The obtained honeycomb fired body had a partition wall thickness of 100 μm and a cell density of 45 cells / cm ² . Further, the porosity of the partition walls of the honeycomb fired body was 50%. Moreover, the average pore diameter of the honeycomb fired body was 18 μm. The honeycomb fired body had a cylindrical shape with a bottom diameter of 320 mm and a length of 300 mm in the cell extending direction. The porosity and average pore diameter are values measured with a mercury porosimeter.

  Next, a polyethylene resin member is pushed into the honeycomb structure along the cell extending direction from the inflow end face side so as to destroy the end of the predetermined partition wall, and a part of the partition wall (inflow end part) is lost. It was. Thereafter, in the same manner, a part of the partition wall (outflow end portion) on the outflow end face side was omitted.

  Next, a plugging material was filled in a part of a region formed by removing a part of the partition so that a hole communicating with an adjacent cell was left. That is, the plugging material was filled in the cell shallower than the depth of the missing part. Thereafter, firing was performed again. In this way, a honeycomb structure made of porous ceramic was produced.

  The manufactured honeycomb structure was a honeycomb structure as shown in FIG. The arrangement pattern of the cell group was as shown in FIG. 5A. That is, the inlet cell, the both-end plugged cell, and the outlet cell are arranged so that the centers of the three cells constituting the cell group are located on the same straight line. There are a plurality of cell groups, which are arranged vertically and horizontally.

  The opening area of the first flow hole was 0.3 times the average value of the cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group. Moreover, the opening area of the 2nd through-hole was 0.3 times the average value of the cross-sectional area of the inlet cell which comprises a cell group, a both-ends plugged cell, and an outlet cell. In calculating the opening area, 20 cell groups were selected randomly (randomly).

  Moreover, the ratio of the cell group was 100%. The cell group ratio is the ratio of “number of cell groups” to “value of 1/3 of the total number of cells”. Also, when counting the “number of cell groups”, the same cell is not counted twice. That is, the “number of cell groups” can also be referred to as the number of plugged cells at both ends. It should be noted that cells are deformed by the outer peripheral wall, or cells in which one or more sides forming the cell are part of the outer peripheral wall (hereinafter referred to as “incomplete cells”) are counted. Moreover, the shape of the opening part of the 1st circulation hole and the 2nd circulation hole was a rectangle. The widths of the openings of these flow holes were the same as the inner dimensions of the cells. That is, as described above, a part of the partition wall which was destroyed by pushing the polyethylene resin member into the honeycomb structure did not remain like a so-called burr. For example, in FIG. 3, it can be said that a part of the partition wall remains like a so-called burr.

  Next, the obtained honeycomb structure was evaluated by measuring “collection efficiency”, “initial pressure loss”, and “pressure loss after ash deposition” by the following methods. The results are shown in Table 1.

[Collection efficiency]
Exhaust gas (200 ° C.) containing soot of “a soot generator that generates soot by burning diesel fuel (light oil)” was passed through the honeycomb structure. Soot contained in the exhaust gas before passing through the honeycomb structure was collected with a filter paper, and the weight (W1) of the soot was measured. Soot contained in the exhaust gas that passed through the honeycomb structure was collected with a filter paper, and the weight (W2) of the soot was measured. The obtained (W1) and (W2) were substituted into the following equation (1) to obtain the collection efficiency (%).
Formula (1): ((W1-W2) / W1) × 100

  Thereafter, the collection efficiency was evaluated according to the following criteria. Corresponding to each, when the collection efficiency of the comparative example having only the inflow end face or only the outflow end face has a plugging portion (indicated as “TE1 to TE6” in Table 2) is improved by 15% or more. A ”. “B” is defined as 10% or more and less than 15%. “C” is defined as 5% or more and less than 10%. When it was less than 5%, it was set as “D”. In general, the improvement of the collection efficiency is good if it is 5% or more (practical). The results are shown in Table 1.

[Initial pressure loss]
“Initial pressure loss” was measured by flowing air at atmospheric pressure (1 atm) and room temperature (20 ° C.) at 15 m ³ / min through the honeycomb structure. Thereafter, the initial pressure loss was evaluated according to the following criteria.

  When the pressure loss is reduced by 30% or more compared to the pressure loss of the comparative example (indicated in Table 2 as “PD1 to PD3”) having plugged portions on both the inlet side and the outlet side corresponding to each Is “A”. When it is less than 30% and decreases by 15% or more, it is defined as “B”. When it is less than 15% and decreases by 5% or more, it is defined as “C”. In the case of a decrease of less than 5%, “D” was assigned. In general, the reduction in the initial pressure loss is good if it is 5% or more (that is, it is practical). The results are shown in Table 1.

[Pressure loss after ash deposition]
The ash discharged from the engine in an evaluation test or the like was previously collected and prepared, and the ash was used. First, 100 g of ash from the inflow end face was put into the honeycomb structure with the inflow end face of the honeycomb structure facing upward. Next, this honeycomb structure was mounted on an exhaust pipe of a 6-cylinder, 6000 cc diesel engine and operated under conditions of 2000 rpm and 100 Nm. Then, “initial pressure loss after ash deposition” was measured 10 minutes after starting the engine. Thereafter, the initial pressure loss after ash deposition was evaluated according to the following criteria. The case where “initial pressure loss after ash deposition” is an increase of 5% or less from “initial pressure loss” is defined as “A”. “B” indicates that the increase is more than 5% and 10% or less. “C” indicates that the increase is more than 10% and 20% or less. When the increase was more than 20%, “D” was assigned. Any increase of 20% or less is practical. The results are shown in Table 1.

  The honeycomb structure of the present example has an evaluation of “collection efficiency” of “A”, an evaluation of “initial pressure loss” of “C”, and an evaluation of “pressure loss after ash deposition”. Was “B”.

  In Tables 1 and 2, “integral” in the “structure” column indicates that the honeycomb structure is composed of one extruded structure as in this example. “Segment” in the “Structure” column indicates that the honeycomb structure is formed by joining a plurality of segment honeycomb structures with a bonding material.

(Examples 2 to 22, Comparative Examples 1 to 9)
First, for Examples 2 to 18, honeycomb structures satisfying the conditions shown in Tables 1 and 2 were produced in the same manner as in Example 1.

  For Examples 19 to 22, segment honeycomb structures having a cross section of 40 mm long × 40 mm wide and 300 mm long were prepared. A manufactured segment honeycomb structure bonded with a bonding material (honeycomb bonded body) was manufactured, and the outer periphery of the honeycomb bonded body was ground. Thereafter, an outer peripheral coating material having a thickness of 1 mm was further applied to produce a honeycomb structure having a diameter of 320 mm and a length of 300 mm. Note that the thickness of the bonding material was 1 mm.

  Comparative Examples 1 to 9 were honeycomb structures having no flow holes communicating with adjacent cells and plugged cells at both ends plugged. In addition, these honeycomb structures are conventional honeycomb structures having plugged portions on both end faces, only the inflow end face, or only the outflow end face in a staggered manner. Comparative Examples 1-3 are comparative examples corresponding to Examples 1-8, 11, 12, and 15-18. Comparative Examples 4 to 6 are comparative examples corresponding to Examples 9, 10, 13, and 14. Comparative Examples 7-9 are comparative examples corresponding to Examples 19-22.

  As for “collection efficiency”, one of the two comparative examples having a plugging portion on “only the inflow end surface” or “only the outflow end surface” corresponding to each example has the better collection efficiency. The evaluation was based on (that is, the one with the higher collection efficiency). For example, the collection efficiency in the honeycomb structure of Example 1 was evaluated based on the better of the collection efficiencies TE1 and TE2 in the honeycomb structures of Comparative Examples 2 and 3.

  Each honeycomb structure was evaluated in the same manner as in Example 1 by measuring “collection efficiency”, “initial pressure loss”, and “pressure loss after ash deposition”. The results are shown in Tables 1 and 2. In FIG. 2, “both end faces” in the column “placement of plugging portions” are plugged portions formed at the end portion of the predetermined cell on the inflow end surface side and the end portion of the remaining cells on the outflow end surface side. This indicates that the plugged portions are arranged so as to form a so-called checkered pattern alternately (staggered) on both end faces. In FIG. 2, “only the inflow end face” in the column “placement of the plugging part” is that the plugging part is disposed only at the end part on the inflow end face side, and the plugging part is provided at the end part on the outflow end face side. This indicates that the plugging portion is disposed so as to form a so-called checkered pattern on the inflow end surface. In FIG. 2, “only the outflow end face” in the column “placement of the plugging part” is that the plugging part is disposed only at the end part on the outflow end face side, and the plugging part is provided at the end part on the inflow end face side. This indicates that the plugging portion is arranged so as to form a so-called checkered pattern on the outflow end surface.

  It was confirmed that the honeycomb structures of Examples 1 to 22 had better initial pressure loss and better collection efficiency than the honeycomb structures of Comparative Examples 1 to 9. Moreover, the increase in pressure loss after ash deposition was small, and it was confirmed that maintenance work to be performed when ash accumulated was unnecessary. In addition, after the test, the honeycomb structure was disassembled and the inside of the cell was observed, but the accumulation of ash was small, and it is considered that most of the ash was discharged together with the exhaust gas from the engine.

  The honeycomb structure of the present invention can be used as a filter for purifying exhaust gas discharged from an automobile or the like.

DESCRIPTION OF SYMBOLS 1,3: Partition, 1a: 1st common partition, 1b: 2nd common partition, 2: Cell, 2a: Inlet cell, 2b: Both-end plugged cell, 2c: Outlet cell, 5: Cell group, 7: First 1 flow hole, 8: second flow hole, 10: honeycomb substrate, 11: inflow end surface, 12, 112: outflow end surface, 20: resin member, 23: plugging material, 25: plugging portion, 26: Outer peripheral wall, 50: honeycomb fired body, 100: honeycomb structure.

Claims (8)

A honeycomb base material having partition walls that define a plurality of cells extending from an inflow end surface, which is one end surface into which the fluid flows, to an outflow end surface, which is the other end surface from which the fluid flows out, serving as a fluid flow path;
A plugging portion disposed in the opening of the cell of the honeycomb substrate,
A plurality of the cells include both-end plugged cells in which the plugging portions are disposed at both the inflow end surface side and the outflow end surface side, and the both end plugged cells are adjacent to the outflow end surface side. An inlet cell in which the plugged portion is disposed only in the opening, and an outlet cell in which the plugged portion is disposed only in the opening on the inflow end surface side adjacent to the both-end plugged cells; Including at least one cell group consisting of the three cells
The partition wall forming the both-end plugged cells constituting the cell group, the first common partition wall being the common partition wall partitioning both the inlet cell and the both-end plugged cells; A second common partition wall that is a common partition wall that partitions both the exit cell and the both-end plugged cells, and
A first flow hole is formed at an end of the first common partition wall on the outflow end surface side,
A honeycomb structure in which a second flow hole is formed at an end of the second common partition wall on the inflow end face side.   In the cross section perpendicular to the cell extending direction of the honeycomb base material, the first center that is the center of the inlet cell, the second center that is the center of the both-end plugged cells, and the center of the outlet cell. The honeycomb structure according to claim 1, wherein the inlet cell, the plugged cells at both ends, and the outlet cell are arranged so that three centers are located on the same straight line.   In the cross section perpendicular to the cell extending direction of the honeycomb substrate, the inlet cells, the both-end plugged cells, and the outlet cells constituting one of the cell groups are arranged in an L shape. The honeycomb structure according to claim 1.   The opening area of the first flow hole is 0.3 to 3.5 times the average value of the cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group. The honeycomb structure according to any one of 1 to 3.   The opening area of the second flow hole is 0.3 to 3.5 times the average value of the cross-sectional areas of the inlet cell, the both-end plugged cell, and the outlet cell constituting the cell group. The honeycomb structure according to any one of 1 to 4.   The honeycomb structure according to any one of claims 1 to 5, comprising a porous ceramic.   The honeycomb structure according to any one of claims 1 to 6, wherein the honeycomb substrate is integrally formed.   The honeycomb structure according to any one of claims 1 to 6, wherein the honeycomb base material has a segment structure including a plurality of honeycomb segments.

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