JP2014113510A - Ceramic honeycomb filter and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a ceramic honeycomb filter, hardly causing melting damage even if the filter is regenerated, hardly causing clogging with ash and reducing an increase in pressure loss, by suppressing the pressure loss when exhaust gas passes, while maintaining collection performance of PM.SOLUTION: A plurality of ceramic honeycomb structures are joined in an exhaust gas-flowing direction on its end surface, and mutual partition walls of at least a part of the plurality of ceramic honeycomb structures are deviatively joined on a cross section orthogonal to the exhaust gas-flowing direction, and in a joined upstream side cell, the cell opening area ratio A=(A/A) being the ratio of the cell opening area Aon the cross section vertical to the exhaust gas-flowing direction and the cell opening area Ain which the cell opening area Aof the cell is reduced by the partition wall of the joined downstream side ceramic honeycomb structure has the average value of 0.9 or less in an optional 5 cells×5 cells=25 cells, and roughness (a maximum height Rz) of a partition wall end surface and a partition wall surface of the downstream side ceramic honeycomb structure is 15 μm or more.

Description

  The present invention relates to a ceramic honeycomb filter used for purifying exhaust gas discharged from an internal combustion engine such as a diesel engine and a method for manufacturing the same.

  Exhaust gas discharged from internal combustion engines such as diesel engines contains a large amount of particulate matter (Particulate Matters, hereinafter referred to as “PM”). When this PM is released into the atmosphere, environmental pollution is caused, so a filter for collecting PM is mounted. For example, as disclosed in Patent Document 1, this filter includes cells 52a and 52b through which a fluid is formed by a porous partition wall 51 shown in FIG. 10, and the end faces of the cells are alternately plugged. A cell 52a in which the fluid inflow end a is opened and the fluid outflow end b is plugged with a plugging material 53b, and the fluid inflow end a is a plugging material 53a. This is a ceramic honeycomb structure 50 having a structure in which cells 52b, which are plugged and whose fluid outlet end b is opened, are alternately arranged. When the exhaust gas flowing into the cell 52a in which the inflow side end a of the ceramic honeycomb structure is opened passes through the porous partition wall 51 to the adjacent cell, PM in the exhaust gas is collected by the partition wall. Collect PM in exhaust gas.

JP 2001-269585 A JP 2004-251137 A

  However, in the ceramic honeycomb structure having a structure for collecting PM as described in Patent Document 1, all the flow holes are plugged at any one end thereof, so that the exhaust gas passes through. Had the problem of increased pressure loss

  Furthermore, if the PM discharged from the diesel engine continues to be collected, the collected PM accumulates in the filter and the filter performance deteriorates. Therefore, the accumulated PM is burned and removed by heating the filter. The filter needs to be regenerated. However, if a large amount of PM is regenerated in a state where a large amount of PM is collected depending on the driving conditions of the vehicle, a large amount of PM burns, heat generation increases, and the partition walls of the ceramic honeycomb structure that is a filter may melt. there were. Furthermore, there is a problem that ash (ash), which is a solid that does not disappear even when the collected PM is burned, gradually accumulates, and the filter is easily clogged.

  In order to solve this, Patent Document 2 discloses that only on one end face b of the ceramic honeycomb structure having cells 62a and 62b through which exhaust gas flows, which is partitioned by a porous partition wall 61, shown in FIG. Disclosed is a ceramic honeycomb structure 60 in which one end b of the cell 62a is plugged 63b, but the cell 62b communicates from one end surface a to the other end surface. It was not enough to maintain the PM collection performance.

  The present invention has been made in view of the above problems, and while maintaining the PM collection performance, suppresses the pressure loss when the exhaust gas passes through, and is difficult to melt even if the filter is regenerated. The object is to obtain a ceramic honeycomb filter in which clogging is unlikely to occur and the increase in pressure loss is low.

  The present inventors have suppressed the pressure loss when exhaust gas passes while maintaining the PM collection performance, are not easily damaged even when the filter is regenerated, and are not easily clogged by ash. As a result of intensive investigations to obtain the above, in the ceramic honeycomb filter of the prior art, the pressure loss when exhaust gas passes increases, and the factor that ash (ash) accumulates and the filter is clogged The plugging material formed at the outflow side end and the inflow side end was found to be present. As a result of intensive studies on the structure of the ceramic honeycomb filter capable of maintaining the PM collection performance without forming the plugging material, the present invention has been conceived.

The ceramic honeycomb filter of the present invention is a ceramic honeycomb filter for removing particulates in exhaust gas, wherein a plurality of ceramic honeycomb structures having cells partitioned by porous partition walls are formed of the ceramic honeycomb structure. The end faces are joined in the direction in which the exhaust gas flows, and the plurality of ceramic honeycomb structures have at least some of the partition walls of the plurality of ceramic honeycomb structures in a cross section orthogonal to the direction in which the exhaust gas flows. A cell opening area A ₀₁ in a cross section perpendicular to the exhaust gas flow direction in the cells of the upstream-side ceramic honeycomb structure in which exhaust gases of the plurality of bonded ceramic honeycomb structures are circulated and flowed. ceramic honeycomb structural cell opening area a ₀₁ of the joined downstream The cell opening area A ₀₂ that is reduced by the partition wall, the specific cell opening area ratio A ₀ = a in (A ₀₂ / A _01), the average value at any desired 5 cells × 5 cells = 25 cells be 0.9 or less Further, the partition wall end face roughness (maximum height Rz) of the downstream ceramic honeycomb structure is 15 μm or more, and the partition wall surface roughness (maximum height Rz) is 15 μm or more.

In the ceramic honeycomb filter of the present invention, the cell opening area ratio (A ₀ ) in the cells and the cell opening area ratios (A ₁ , A ₂ , A ₃ , A ₄ ...) In the cells adjacent to the cells As for the absolute value of the difference, the maximum value in an arbitrary 5 cells × 5 cells = 25 cells is preferably 0.10 or more and less than 1.0.

  In the ceramic honeycomb filter of the present invention, the partition walls of the plurality of ceramic honeycomb structures are joined in the direction of the partition wall thickness so that the shortest distance between the partition walls is shifted by 0.1 to less than 0.5 times the partition wall pitch. Is preferred.

  In the ceramic honeycomb filter of the present invention, it is preferable that the partition walls of the plurality of ceramic honeycomb structures are joined at a position shifted by an angle of 35 to 55 ° with the center of the end face as an axis.

  In the ceramic honeycomb filter of the present invention, the number of the ceramic honeycomb structures is preferably 2 or more and 15 or less.

  In the ceramic honeycomb filter of the present invention, in the cross section orthogonal to the direction in which the exhaust gas flows, the cell has a substantially quadrangular shape, the corner has an arc shape, and the curvature radius of one opposite corner is opposite to the other. It is preferable that the radius of curvature of the corner to be larger is larger.

  In the ceramic honeycomb filter of the present invention, it is preferable that the end surfaces of the plurality of joined ceramic honeycomb structures have an interval of 0.01 to 3.0 mm.

  In the ceramic honeycomb filter of the present invention, it is preferable that an opening ratio of the plurality of ceramic honeycomb structures is 75% or less.

  In the ceramic honeycomb filter of the present invention, it is preferable that the plurality of ceramic honeycomb structures are joined so that the aperture ratios of adjacent ceramic honeycomb structures are different.

  In the plurality of ceramic honeycomb structures, in the cross section parallel to the direction in which the exhaust gas flows, adjacent partition walls are substantially parallel to each other, and 1 to 5 cells in the outer peripheral portion of the ceramic honeycomb structure are It is preferable that a part or end of the cell forms an outer peripheral surface.

  A method for manufacturing a ceramic honeycomb filter of the present invention is a method for manufacturing a ceramic honeycomb filter in which a plurality of ceramic honeycomb structures are joined, and a ceramic clay is extruded into a honeycomb shape, cut into a predetermined length, The dried ceramic honeycomb dried bodies are placed on the end face of the ceramic honeycomb dried body with the partition walls being shifted from each other, and the placed ceramic honeycomb dried bodies are fired to form a plurality of ceramic honeycomb structures. It is characterized by that.

  In the method for manufacturing a ceramic honeycomb filter of the present invention, it is preferable that a coating material is applied to the outer peripheral portions of the plurality of ceramic honeycomb structures after the firing.

  The method for manufacturing a ceramic honeycomb filter of the present invention is a method for manufacturing a ceramic honeycomb filter in which a plurality of ceramic honeycomb structures are joined. The ceramic clay is extruded into a honeycomb shape and cut into a predetermined length. Then, a plurality of dried ceramic honeycomb dried bodies are placed on the end face of the ceramic honeycomb dried body with the partition walls being shifted from each other, and a coating material is applied to the outer peripheral portion of the plurality of ceramic honeycomb dried bodies placed above. And firing.

  The method for manufacturing a ceramic honeycomb filter of the present invention is a method for manufacturing a ceramic honeycomb filter in which a plurality of ceramic honeycomb structures are joined. The ceramic clay is extruded into a honeycomb shape and cut into a predetermined length. A plurality of ceramic honeycomb structures after drying and firing are placed on the end face of the ceramic honeycomb structure with the partition walls being shifted from each other, and a coating material is applied to the outer peripheral portion of the plurality of ceramic honeycomb structures placed as described above It is characterized by applying.

  In the method for manufacturing a ceramic honeycomb filter of the present invention, it is preferable that a bonding material is disposed on a peripheral portion of an end face of the ceramic honeycomb structure, and the plurality of ceramic honeycomb structures are placed via the bonding material.

  In the method for manufacturing a ceramic honeycomb filter of the present invention, an arbitrary partition wall formed from one outer peripheral end to the other outer peripheral end on the end face of one ceramic honeycomb structure of the plurality of ceramic honeycomb structures. Then, after substantially aligning the positioning members, the one ceramic honeycomb structure is moved in the X direction or the Y direction, or moved in both the X direction and the Y direction, or the center of the end face is used as an axis. When the other ceramic honeycomb structure is placed on the end surface of the moved one ceramic honeycomb structure, the outer periphery of the other ceramic honeycomb structure is moved from one outer peripheral end to the other outer periphery. By placing the positioning member approximately in line with any partition formed up to the end, the partitions are shifted from each other. It is preferably location.

  In the method for manufacturing a ceramic honeycomb filter of the present invention, the positioning member is preferably a linear member made of a metal and / or a non-metal, or a light beam.

  According to the present invention, while maintaining the PM collection performance, the pressure loss when exhaust gas passes is kept low, and it is difficult to melt even if regenerated and clogging is difficult to occur in ash, thereby obtaining a ceramic honeycomb filter. be able to.

(a) A schematic cross-sectional view showing a ceramic honeycomb filter as an example of the present invention. (b) The figure which looked at (a) from the end surface side. The cross-sectional enlarged arrow line view in the BB part of Fig.1 (a). (a) A schematic cross-sectional view showing a ceramic honeycomb filter according to another embodiment of the present invention. (b) The figure which looked at (a) from the end surface side. FIG. 4 is an enlarged cross-sectional view taken along the line CC in FIG. The figure which shows the partition intersection part of the ceramic honeycomb structure which concerns on this invention. The figure which looked at the nozzle | cap | die used when extrusion-molding the ceramic honeycomb structure which concerns on this invention from the exit side of the molded object. FIG. 16 is a schematic cross-sectional view showing a ceramic honeycomb filter according to Example 17 of the present invention. Fig. 25 is a schematic sectional view showing a ceramic honeycomb filter according to Example 25 of the present invention. In this invention, the cell of the outer peripheral part of a ceramic honeycomb structure WHEREIN: The schematic cross section which showed that a part or edge part of the flow path formed the outer peripheral surface. The schematic cross section which showed the ceramic honeycomb filter described in patent document 1 which is a prior art. The schematic cross section which showed the ceramic honeycomb filter described in patent document 2 which is a prior art. (a) Schematic diagram showing the cell opening area of an arbitrary cell of the upstream ceramic honeycomb structure 11 through which exhaust gas flows in the present invention. (b) A schematic view showing the cell opening area reduced by the partition wall 121 of the bonded ceramic honeycomb structure 12 on the downstream side. (a) (c) The schematic cross section which showed the ceramic honeycomb filter which is an Example of this invention. (b) The figure which looked at (d) from the end surface side. The schematic diagram which showed the method in which the partition was shifted in the direction of partition wall thickness in the end surface, and the some ceramic honeycomb structure in this invention was mounted | worn. The schematic diagram which showed the method by which the partition was rotated centering on the center of an end surface, and shifted | deviated to the some ceramic honeycomb structure in this invention.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described. However, the present invention is not limited to the following embodiments, and may be appropriately selected based on ordinary knowledge of a person skilled in the art without departing from the gist of the present invention. Needless to say, design changes and improvements can be made.

FIG. 1, FIG. 2, FIG. 3 and FIG. 4 show an example of an embodiment of the ceramic honeycomb filter of the present invention. In the ceramic honeycomb filter 10 of the present invention, a plurality of ceramic honeycomb structures 11 and 12 having cells partitioned by porous partition walls are joined in the direction in which exhaust gas flows at the end face of the ceramic honeycomb structure, In the plurality of ceramic honeycomb structures 11 and 12, in the cross section perpendicular to the direction in which the exhaust gas flows, at least some of the partition walls of the plurality of ceramic honeycomb structures are bonded to each other in a shifted manner. In the cells of the ceramic honeycomb structure 11 on the upstream side through which the exhaust gas of the ceramic honeycomb structures 11 and 12 flows, the cell opening area A ₀₁ in the cross section perpendicular to the exhaust gas flowing direction and the cell opening area A ₀₁ of the cell in but a cell opening area a ₀₂ that is reduced by the partition wall 121 of the ceramic honeycomb structure 12 of the joined downstream, the ratio of That cell opening area ratio A ₀ = has (A ₀₂ / A _01), and the average value is 0.9 or less at any 5 cells × 5 cells = 25 cells, crude partition wall end surface of the downstream ceramic honeycomb structure 12 of The height (maximum height Rz) is 15 μm or more, and the roughness of the partition wall surface (maximum height Rz) is 15 μm or more. As a result, the partition wall 121 of the downstream ceramic honeycomb structure 12 exists at the outlet of the cell of the upstream ceramic honeycomb structure 11, and the flow path through which the exhaust gas flows is narrowed at the joint. Become. Therefore, when the exhaust gas flowing into the ceramic honeycomb filter flows into the cells of the upstream ceramic honeycomb structure 12 after flowing into the cells of the upstream ceramic honeycomb structure 11, the joint portion narrows. Due to the flow path, a pressure difference is generated between adjacent cells, and the roughness (maximum height Rz) of the partition wall end face and the partition wall surface is 15 μm or more, so that the PM in the exhaust gas is reduced by the exhaust gas. It is captured by the partition wall end face and partition wall surface of the downstream ceramic honeycomb structure existing in the circulating cell. In addition, since the flow path communicates from the inlet side end face to the outlet side end face of the ceramic honeycomb filter, the pressure loss when the exhaust gas flows can be kept low while maintaining the PM collection performance.
Furthermore, PM in the exhaust gas is trapped on the partition wall end face and partition wall surface of the joined downstream ceramic honeycomb structure, and a small part of the PM that is not trapped is discharged from the cell. Even if PM is burned to regenerate the filter without accumulating, the heat generated by the combustion does not increase, and the ceramic honeycomb structure is difficult to melt. Furthermore, since the ash remaining after PM burns easily flows out of the ceramic honeycomb filter, clogging hardly occurs.
In the ceramic honeycomb filter 10 of the present invention, the strength of the ceramic honeycomb filter is improved by forming the outer peripheral wall 5 on the outer periphery of the plurality of ceramic honeycomb structures 11 and 12 in which the partition walls are displaced from each other. This is preferable.

The cell opening area ratio is calculated as follows. Light is transmitted from the end face of the joined ceramic honeycomb filter, and the opening of the cell is photographed at the other end face. Or, cut in the range within 10mm in both directions parallel to the direction in which exhaust gas flows from the joint, perpendicular to the direction in which exhaust gas flows, and transmit light from one of the cut end faces, and the other cut Take a picture of the opening of the cell at the end face. The photographed photograph is used to calculate the cell opening area A ₀₁ of the cell and the cell opening area A ₀₂ reduced by the partition wall of the downstream ceramic honeycomb structure to which the cell opening area A ₀₁ of the cell is joined. Then, the aperture area ratio of each cell is calculated as (A ₀₂ / A ₀₁ ).

Here, when the exhaust gas flowing into the ceramic honeycomb filter flows into the cells of the upstream ceramic honeycomb structure 12 after flowing into the cells of the upstream ceramic honeycomb structure 11, the joint portion is narrowed. The flow path creates a pressure difference between adjacent cells, and PM in the exhaust gas is easily trapped on the partition wall end face and partition wall surface of the downstream ceramic honeycomb structure existing in the cell through which the exhaust gas flows. For this purpose, the cell opening area ratio A ₀ = (A ₀₂ / A ₀₁ ) is preferably 0.85 or less in average for any 5 cells × 5 cells = 25 cells, and the roughness (maximum height) of the partition wall end face The thickness Rz) is preferably 20 μm or more, and the partition wall surface roughness (maximum height Rz) is preferably 20 μm or more. More preferably, the cell opening area ratio A ₀ = (A ₀₂ / A ₀₁ ) has an average value of 0.80 or less for any 5 cells × 5 cells = 25 cells, and the roughness (maximum height) Rz) is 25 μm or more. Furthermore, it is preferable that the roughness of the partition wall surface is larger than the roughness of the partition wall end face because PM is easily captured on the partition wall surface.

In the ceramic honeycomb filter of the present invention, when the exhaust gas flowing into the ceramic honeycomb filter flows into the cells of the ceramic honeycomb structure 12 on the downstream side after flowing into the cells of the ceramic honeycomb structure 11 on the upstream side, The pressure difference generated between adjacent cells is increased by the flow path having a narrow joint, and the PM in the exhaust gas is separated from the partition wall end face of the downstream ceramic honeycomb structure existing in the cell through which the exhaust gas flows. In order to be easily captured on the partition wall surface, the cell opening area ratio (A ₀ ) in the cell and the cell opening area ratio (A ₁ , A ₂ , A ₃ , A ₄ ...) In the cell adjacent to the cell. The absolute value of the difference between the maximum value in any 5 cells × 5 cells = 25 cells is preferably 0.10 or more and less than 1.0, and more preferably 0.20 or more and 0.5 or less.

Here, the cell opening area ratio in the cell adjacent to the cell, for example, in the case of square cells, as shown in FIG. 12, in the ceramic honeycomb structure 11 on the upstream side, adjacent to the cell having a cell opening area A ₀₁ Cell opening areas A ₁₁ , A ₂₁ , A ₃₁ , A _{41 of} the cells to be reduced are reduced by the partition walls 121 of the joined ceramic honeycomb structure 12 on the downstream side, A ₁₂ , A ₂₂ , A ₃₂ , A ₄₂ , ie, A ₁ = (A ₁₂ / A ₁₁ ), A ₂ = (A ₂₂ / A ₂₁ ), A ₃ = (A ₃₂ / A ₃₁ ), A ₄ = (A ₄₂ / A ₄₁ ) Means that. The absolute value of the difference between the cell opening area ratio (A ₀ ) in the cell and the cell opening area ratio (A ₁ , A ₂ , A ₃ , A ₄ ) in the cell adjacent to the cell is (A ₀ -A ₁ ), (A ₀ -A ₂ ), (A ₀ -A ₃ ), (A ₀ -A ₄ ) absolute values, and among these values, arbitrary 5 cells × 5 cells = 25 cells It is preferable that the maximum value of is 0.10 or more and less than 1.0.

In the ceramic honeycomb filter of the present invention, as a specific embodiment in which the cell opening area ratio A ₀ = (A ₀₂ / A ₀₁ ) is an average value of 0.9 or less in any 5 cells × 5 cells = 25 cells, FIG. As shown in FIG. 2, the partition walls of the plurality of ceramic honeycomb structures are joined in the direction of the partition wall thickness, with the shortest distance between the partition walls being shifted by 0.1 to less than 0.5 times the partition wall pitch. be able to. The partition walls of the plurality of ceramic honeycomb structures are joined in the direction of the partition wall thickness so that the shortest distance between the partition walls is shifted by not less than 0.1 times and less than 0.5 times the partition wall pitch as shown in FIG. The interval X or Y between the partition walls 111 and 121 of the plurality of ceramic honeycomb structures 11 and 12 is 0.1 times or more and less than 0.5 times the partition wall pitch. After the partition walls of the plurality of ceramic honeycomb structures flow into the cells of the ceramic honeycomb structure on the upstream side because the shortest distance between the partition walls is shifted by not less than 0.1 times the partition wall pitch in the partition wall thickness direction. When flowing to the cells of the joined ceramic honeycomb structure on the downstream side, the pressure difference generated between adjacent cells is increased due to the narrow flow path of the joined portion, and the PM in the exhaust gas is reduced by the exhaust gas. This is preferable because it can be easily captured on the partition wall end face or partition wall surface of the downstream ceramic honeycomb structure existing in the circulating cell. On the other hand, since the maximum shortest distance between the partition walls is less than 0.5 times the partition wall pitch, the shortest distance between the partition walls is preferably 0.1 times or more and less than 0.5 times the partition wall pitch.

As another specific mode in which the cell opening area ratio A ₀ = (A ₀₂ / A ₀₁ ) has an average value of 0.9 or less in any 5 cells × 5 cells = 25 cells, FIG. 3 and FIG. As shown, the partition walls of the plurality of ceramic honeycomb structures can be joined at a position shifted by an angle of 35 to 55 ° with the center of the end face as an axis. The partition walls of the plurality of ceramic honeycomb structures are joined at a position shifted by an angle of 35 to 55 ° with the center of the end face as an axis, as shown in FIGS. 3 and 4. This means that the partition walls 111 and 121 of 11 and 12 are joined with an angle θ = 35 to 55 °.

  Further, the partition walls of the plurality of ceramic honeycomb structures are shifted by not less than 0.1 times and less than 0.5 times the partition wall pitch in the direction of the partition wall thickness, and further, 35 to It is assumed that the bonding is performed at a position shifted by an angle of 55 °, or the bonding is performed at a position shifted by an angle of 35 to 55 ° about the center of the end face of a plurality of ceramic honeycomb structures having different partition wall pitches. It is also possible to do.

  The partition walls of the plurality of ceramic honeycomb structures are shifted in the direction of the partition wall thickness by the shortest distance between the partition walls being 0.1 times or more and less than 0.5 times the partition wall pitch, and 35 to 55 ° about the center of the end face. Are joined at an angle shifted position of 35 to 55 ° around the center of the end faces of the plurality of ceramic honeycomb structures. In this state, the end faces of the plurality of ceramic honeycomb structures are This means that the centers are shifted from 0.1 to less than 0.5 times the partition wall pitch.

  When the exhaust gas flowing into the ceramic honeycomb filter flows into the cells of the upstream ceramic honeycomb structure after flowing into the cells of the bonded ceramic honeycomb structure on the upstream side, the exhaust gas is adjoined by the flow path narrowed at the joint. A pressure difference occurs between the cells and the PM in the exhaust gas is trapped on the partition wall end face and the partition wall surface of the downstream ceramic honeycomb structure existing in the cell through which the exhaust gas flows. Two or more honeycomb structures need to be joined. When the number of the plurality of ceramic honeycomb structures to be joined increases, the partition wall end face portion of the joined downstream ceramic honeycomb structure that can capture PM increases, and thus the PM collection performance is improved. It is. However, if the number of the plurality of ceramic honeycomb structures to be joined increases, the pressure loss when the exhaust gas flows increases. Therefore, the number of the ceramic honeycomb structures may be 2 or more and 15 or less. preferable. More preferably, it is 2 or more and 12 or less. In addition, the ceramic honeycomb structures to be joined do not have to be displaced all at the same, but combinations of displacement amounts with different minimum distances between the partition walls, or displacements with different angles rotated about the center of the end face. Combinations of quantities or combinations thereof may be used.

In the ceramic honeycomb filter of the present invention, the corners of the cells have an arc shape in a cross section perpendicular to the direction in which the exhaust gas flows, whereby the strength at the joint is improved. When the exhaust gas flowing into the ceramic honeycomb filter flows into the cells of the upstream ceramic honeycomb structure after flowing into the cells of the upstream ceramic honeycomb structure, the downstream ceramic honeycomb structure Since the area of the partition wall end face increases, PM is easily captured. Furthermore, a pressure difference between adjacent cells is likely to occur due to the flow path with a narrow joint, and the partition wall end face of the downstream ceramic honeycomb structure in which PM in the exhaust gas exists in the cell through which the exhaust gas flows And is easily trapped on the partition wall surface. Further, as shown in FIG. 5, in the cross section orthogonal to the direction in which the exhaust gas flows, the cell has a substantially square shape, the corner has an arc shape, and the curvature radius R ₁ of one opposing corner has the other Is larger than the radius of curvature R _{2 at} the opposite corners, the pressure difference generated between adjacent cells increases, PM in the exhaust gas is easily captured by the partition walls, and the PM collection performance is improved. Can be maintained.

  In the ceramic honeycomb filter of the present invention, the interval between the end faces of the plurality of bonded ceramic honeycomb structures can be 0.01 to 3.0 mm. Thereby, a space for capturing PM in the exhaust gas is wider between the cell outlet portion of the upstream ceramic honeycomb structure and the partition wall end face and partition wall surface of the joined downstream ceramic honeycomb structure. Since it is formed, the PM collection performance is improved. Furthermore, it is preferable because the pressure loss when the exhaust gas flows can be kept low. However, when the distance between the end faces of the plurality of bonded ceramic honeycomb structures exceeds 3.0 mm, the pressure difference generated between the adjacent cells due to the narrow flow path of the bonded portion is reduced, and the PM in the exhaust gas is separated from the partition wall. This is not preferable because it may be difficult to be trapped and the function of maintaining good PM trapping performance may be deteriorated. The formation of the 0.01 to 3.0 mm interval will be described later.

  In the ceramic honeycomb filter of the present invention, the aperture ratio of the plurality of ceramic honeycomb structures is preferably 75% or less. Thereby, the pressure loss at the time of exhaust gas distribution can be suppressed low, maintaining PM collection performance. When the opening ratio exceeds 75%, the strength of the ceramic honeycomb structure is lowered, and it becomes difficult to join a plurality of ceramic honeycomb structures, which is not preferable. In order to suppress the pressure loss when the exhaust gas flows, the opening ratio is preferably 40% or more.

  In the ceramic honeycomb filter of the present invention, the plurality of ceramic honeycomb structures may be joined such that adjacent ceramic honeycomb structures have different aperture ratios. As a result, the pressure difference generated between the adjacent cells is increased due to the narrow flow path of the joint, and the pressure loss when exhaust gas flows can be kept low while PM is well collected. preferable.

As shown in FIGS. 9 (a) and 9 (b), the ceramic honeycomb filter of the present invention has a structure in which adjacent partition walls 1 are substantially parallel to each other in a cross section parallel to the direction in which exhaust gas flows, and the ceramic honeycomb structure. 1 to 5 cells 2 _out of the outer peripheral part of the cell may have a part or an end of the cell open to the outer peripheral surface 4. Thereby, since the partition wall is inclined with respect to the direction in which the exhaust gas flows, PM is easily trapped on the partition wall end face and the entire partition wall surface of the downstream ceramic honeycomb structure. Therefore, it is preferable because the pressure loss when exhaust gas flows can be kept low while PM is well collected. However, it is not preferable that six or more cells in the outer peripheral portion have a part or end of the cell opened in the outer peripheral surface because the pressure loss when the exhaust gas flows increases.

  The ceramic honeycomb filter of the present invention has a porosity of 50 to 80%, a partition wall thickness of 0.20 to 0.50 mm, and a cell pitch of 1.0 to 3.0 mm. This is preferable because PM is easily captured on the end face of the partition wall of the ceramic honeycomb structure on the side and the surface of the partition wall. More preferably, the porosity is 55 to 70%, the partition wall thickness is 0.25 to 0.45 mm, and the cell pitch is 1.2 to 2.0 mm.

The ceramic honeycomb filter of the present invention can be manufactured as follows.
(Manufacture of ceramic honeycomb structure)
A binder, a lubricant, a pore former, and water are added to a ceramic raw material, mixed and kneaded to prepare a plasticized ceramic clay. Ceramic raw materials are cordierite, cordierite forming raw material, silicon carbide, silicon-silicon carbide based composite material, silicon nitride, mullite, alumina, spinel, silicon carbide-cordierite based composite material, lithium aluminum silicate, aluminum titanate It is preferable that it is at least 1 sort (s) selected from the group which consists of. Among these, a cordierite forming raw material is preferable. The cordierite forming material means a raw material which becomes cordierite by firing, SiO ₂ is 42 to 56 wt%, Al ₂ O ₃ is 30 to 45 wt%, the chemical that MgO is in the range of 12 to 16 wt% It is a ceramic raw material blended to have a composition. Specific examples include those containing a plurality of inorganic raw materials selected from talc, kaolin, calcined kaolin, alumina, aluminum hydroxide, and silica in a proportion such that the above chemical composition is obtained. At this time, by using a material having an average particle diameter of 5 to 70 μm for the pore former, a ceramic honeycomb member having a partition wall end face or partition wall surface roughness (maximum height Rz) of 15 μm or more can be obtained. The pore former is not particularly limited as long as it is a material that can have a roughness of 15 μm or more by forming pores on the partition wall end face and the partition wall surface of the fired ceramic honeycomb structure. Resin, foamed resin, foamed resin, ceramic coating resin, corn starch, flour and the like can be used.

  Next, the ceramic clay is extruded using a honeycomb-shaped extrusion mold to produce a ceramic honeycomb molded body having a predetermined length. Then, the ceramic honeycomb formed body is dried in a hot air furnace, a heat treatment furnace, a microwave, or the like to obtain a ceramic honeycomb dried body.

Here, as shown in FIG. 6, the extrusion mold is formed with curved surfaces (R portions) R ₁ and R ₂ at the corners of the molding groove 32 formed in the extrusion die 31. The cell corner that is the intersection of the partition walls 111 of the ceramic honeycomb molded body shown in FIG. 5 has an arc shape, and the radius of curvature R ₁ of one opposing corner is larger than the radius of curvature R _{2 of the} other opposing corner. can do.

(Manufacture of ceramic honeycomb filters)
Next, the end faces of the dried ceramic honeycomb dried bodies are ground with a grindstone so as to be substantially orthogonal to the direction in which the exhaust gas flows. For the end face of the ceramic honeycomb member manufactured using the pore former, a grindstone having a grain size of about # 50 to # 270 may be used so that the roughness (maximum height Rz) of the partition wall end face is 15 μm or more. preferable. Then, on the end face, the partition walls are shifted and placed, and a plurality of ceramic honeycomb dried bodies in the mounted state are fired, whereby a ceramic honeycomb filter in which the partition walls are shifted and joined can be obtained.

After firing, a coating material is applied to the outer peripheral portions of the plurality of ceramic honeycomb structures, so that the plurality of ceramic honeycomb structures are integrated, and are less likely to be damaged at the joint where the plurality of ceramic honeycomb structures are placed. .
As the coating material, a ceramic raw material mixed with a binder and water can be used. The ceramic raw material may be the same material as the ceramic honeycomb structure or a different material. Cordierite, cordierite forming raw material, silicon carbide, silicon-silicon carbide based composite material, silicon nitride, mullite, alumina, At least one selected from the group consisting of silica, spinel, silicon carbide-cordierite composite material, lithium aluminum silicate, and aluminum titanate can be used.

Moreover, the plurality of dried ceramic honeycomb dried bodies are placed with their partition walls being shifted from each other on the end face, and the coating material is applied to the outer peripheral portions of the plurality of ceramic honeycomb dried bodies in the placed state and fired. Thus, it is possible to obtain a ceramic honeycomb filter in which the partition walls are displaced and joined. In this case, since the ceramic honeycomb structure and the coating material are fired and integrated, the ceramic honeycomb filter in which the partition walls are displaced from each other and bonded is more preferable.
As the coating material, a ceramic raw material mixed with a binder and water can be used. The ceramic raw material may be the same material as the ceramic honeycomb structure or a different material, such as cordierite forming raw material, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, silica, spinel, silicon carbide At least one selected from the group consisting of cordierite-based composite materials, lithium aluminum silicate, and aluminum titanate can be used.

  Moreover, the plurality of dried ceramic honeycomb dried bodies are fired, and the fired ceramic honeycomb structures are placed on their end faces with the partition walls being shifted from each other. By applying a coating material to the outer peripheral part of the ceramic honeycomb filter, the partition walls can be displaced and joined together.

Moreover, as shown in FIG. 7, after forming the chamfer 6 or the R portion 7 at the corners of the end faces of the plurality of ceramic honeycomb structures 11, 12, 13, and 14, the partition walls are shifted and placed, By applying a coating material to the outer peripheral portions of the plurality of ceramic honeycomb structures that are placed, it is possible to obtain a ceramic honeycomb filter in which the partition walls are displaced and joined. Thereby, since the coating material is formed thicker than the outer peripheral portion at the joint portion where the plurality of ceramic honeycomb structures are placed, it is preferable because the joint portion is strengthened.
Note that the chamfering formed on the end faces of the plurality of ceramic honeycomb structures or the R portion may be formed either after drying or firing the plurality of ceramic honeycomb structures.

Further, as shown in FIG. 9, the ceramic honeycomb structure in which 1 to 5 cells 2 _{out in} the outer peripheral part and the part or the end of the cell form the outer peripheral surface 4 is, for example, It is obtained in this way. The extruded ceramic honeycomb molded body is dried to obtain a dried ceramic honeycomb body, and then the outer peripheral portion of the dried body is processed and removed. At this time, the honeycomb dried body after processing and removal is processed so that the outer peripheral surface 4 is inclined with respect to the partition wall 1, and a part or end of the 1 to 5 cells 2 _out of the outer peripheral portion Process to form. Next, both ends of the dried body are processed so as to be substantially perpendicular to the outer peripheral surface 4.
Alternatively, it can be obtained as follows. In the process of extruding the ceramic honeycomb formed body in the longitudinal direction (gravity direction) with an extruder, the direction and size of the holding force applied to support the weight is adjusted at the lower end of the extruded ceramic honeycomb formed body. Thus, a ceramic honeycomb formed body in which the cells are curved with respect to the direction in which the exhaust gas flows is manufactured. The ceramic honeycomb formed body thus obtained is dried to obtain a ceramic honeycomb dried body. Then, the outer peripheral portion of the dried body is processed so that the outer peripheral surface 4 of the dried honeycomb body after processing is inclined with respect to the partition wall 1, and a part or end of 1 to 5 cells 2 _out of the outer peripheral portion. The part is processed so as to form the outer peripheral surface 4. Next, both ends of the dried body are processed so as to be substantially perpendicular to the outer peripheral surface 4. In addition, although the example which processes and removes the outer peripheral part of a ceramic honeycomb dried body was shown above, it cannot be overemphasized that it can obtain by processing and removing the outer peripheral part of the sintered body after baking a ceramic honeycomb dried body.

(Joining material)
The plurality of ceramic honeycomb structures placed with the partition walls being shifted can also be placed via a bonding material, the joint portions of the plurality of ceramic honeycomb structures are strengthened, and the plurality of ceramic honeycomb structures are placed. It becomes difficult to break at the placed joint.
As shown in FIGS. 13 (a) and 13 (b), the bonding material 21 is disposed at the peripheral edge portion of the end faces of the plurality of ceramic honeycomb structures 11 and 12, and the plurality of ceramic honeycomb structures are placed via the bonding material. can do. The bonding material 21 may be disposed on the dried ceramic honeycomb structure or may be disposed on the fired ceramic honeycomb structure. The peripheral edge portion of the end face of the ceramic honeycomb structure in which the bonding material is disposed refers to a range of 5 times the cell pitch from the outermost peripheral portion of the end face. Further, as shown in FIGS. 13 (c) and 13 (d), the bonding material does not need to be disposed over the entire peripheral portion, and is disposed at a desired portion of the peripheral portion according to the degree to which the bonding portion is not easily damaged. May be.

  As the bonding material, for example, the following can be used. Ceramic materials mixed with ceramic fibers and inorganic binders, or ceramic fibers having heat resistance, ceramic particles, cement, and the like can be used alone or in combination. Furthermore, an organic binder, an inorganic binder, etc. can also be mixed as needed. The ceramic raw material may be the same material as the ceramic honeycomb structure or a different material. Cordierite, cordierite forming raw material, silicon carbide, silicon-silicon carbide based composite material, mullite, alumina, silica, spinel At least one selected from the group consisting of silicon carbide-cordierite composite material, lithium aluminum silicate, and aluminum titanate can be used.

  As shown in FIG. 13, a plurality of ceramic honeycomb structures 11 and 12 are placed via the bonding material 21 so that a gap between the end faces of the plurality of ceramic honeycomb structures 11 and 12 is 0.01 to 3.0 mm. It can be. The bonding material 21 is disposed on the end surface, but can also be disposed in the cells on the end surface, whereby a plurality of ceramic honeycomb structures can be firmly bonded.

(Method of placing the partition walls while shifting them)
Next, a method for placing a plurality of ceramic honeycomb structures with the partition walls shifted from each other on the end surfaces will be described.
The end face of the ceramic honeycomb structure is cut or ground to make the total length of the ceramic honeycomb structure a predetermined length. Here, the total length can be determined as appropriate depending on the number of ceramic honeycomb structures to be joined, and it is preferable that all ceramic honeycomb structures to be joined have the same overall length. It is not necessary for the overall length to be the same, and ceramic honeycomb structures having different overall lengths may be joined. Needless to say, the ceramic honeycomb structure whose end face is processed may be either unfired after drying or fired.

  FIG. 14 and FIG. 15 show a joining device 80 for mounting and joining a plurality of ceramic honeycomb structures with their partition walls shifted from each other at their end faces. The joining apparatus 80 includes a table 81 for placing a plurality of ceramic honeycomb structures and a positioning member. As the positioning member, a linear member made of metal and / or non-metal, or a light beam can be used, and as a linear member made of metal and / or non-metal, steel wire, copper wire, ceramic fiber wire, Nylon fiber, thread, string or the like can be used as a light beam, such as a beam beam, a laser beam, or the like. 14 and 15 includes two laser light sources 82 and 83 as positioning members. The table 81 can move in the X and Y directions on the horizontal plane, and can rotate around the center of the table 81 as an axis. The two laser light sources 82 and 83 are arranged at positions where the optical axes 821 and 831 of the respective laser beams are orthogonal to each other. The laser light sources 82 and 83 are supported by the respective columns 84 and 85 and can move in the vertical direction, and can be fixed at arbitrary positions.

Next, a method will be described in which a plurality of ceramic honeycomb structures are placed with their partition walls shifted from each other in the direction of the partition wall thickness at the end faces.
(a ₁ ) First, the laser light sources 82 and 83 are fixed at a position substantially coincident with the length of the first ceramic honeycomb structure 11 to turn on the power. On the table 81, an arbitrary partition wall 111-2 formed on the end surface of the first ceramic honeycomb structure 11 from one outer peripheral end to the other outer peripheral end, and an optical axis 821 of the laser beam. Further, the partition wall 111-3 in a direction perpendicular to the arbitrary partition wall 111-2 and the optical axis 831 of the laser beam are mounted so as to substantially match (FIG. 14 (a)).
(b ₁ ) Next, the table 81 is moved in the X direction, the Y direction, or both the X direction and the Y direction within a range not less than 0.1 times and less than 0.5 times the partition wall pitch (FIG. 14 (b)). .
(c ₁ ) Next, the laser light sources 82 and 83 are moved and fixed to positions that substantially coincide with the total length of the second ceramic honeycomb structure 12. Then, on the end face of the second ceramic honeycomb structure 12, an arbitrary partition wall 121-2 formed from one outer peripheral end to the other outer peripheral end and the optical axis 821 of the laser beam substantially coincide with each other. Furthermore, the partition 121-3 in a direction perpendicular to the arbitrary partition 121-2 and the optical axis 831 of the laser beam are mounted so as to substantially coincide (FIG. 14 (c)).
(d ₁ ) Next, the table 81 is moved in the X direction, the Y direction, or both the X direction and the Y direction within a range not less than 0.1 times and less than 0.5 times the partition wall pitch (FIG. 14 (d)). .
(e ₁ ) Next, the laser light sources 82 and 83 are moved and fixed to positions that substantially coincide with the total length of the third ceramic honeycomb structure 13. Then, on the end surface of the third ceramic honeycomb structure 13, an arbitrary partition wall 131-2 formed from one outer peripheral end to the other outer peripheral end and the optical axis 821 of the laser beam substantially coincide with each other. Furthermore, the partition 131-3 in the direction perpendicular to the arbitrary partition 131-2 and the optical axis 831 of the laser beam are placed so as to substantially coincide (FIG. 14 (e)).
When four or more ceramic honeycomb structures are mounted, a desired number of ceramic honeycomb structures can be mounted by repeating (b ₁ ) to (e ₁ ) in the same manner.

In the case where a plurality of ceramic honeycomb structures are mounted with the partition walls being rotated and displaced with the center of the end surface as an axis at the end surface, the following is performed.
(a ₂ ) The laser light source 82 is fixed at a position substantially coincident with the total length of the first ceramic honeycomb structure 11 and the power is turned on. On the table 81, an arbitrary partition wall 111-2 formed on the end surface of the first ceramic honeycomb structure 11 from one outer peripheral end to the other outer peripheral end, and an optical axis 821 of the laser beam. It is mounted so as to substantially match (FIG. 15 (a)).
(b ₂ ) Next, the table 81 is rotationally moved within an angle range of 35 to 55 ° (FIG. 15 (b)).
(c ₂ ) Next, the laser light source 82 is moved and fixed to a position substantially coincident with the total length of the second ceramic honeycomb structure 12. Then, on the end face of the second ceramic honeycomb structure 12, an arbitrary partition wall 121-2 formed from one outer peripheral end to the other outer peripheral end and the optical axis 821 of the laser beam substantially coincide with each other. Place it (Fig. 15 (c)).
(d ₂ ) Next, the table 81 is rotated and moved within an angle range of 35 to 55 ° (FIG. 15 (d)).
(e ₂ ) Next, the laser light source 82 is moved and fixed to a position substantially coincident with the total length of the third ceramic honeycomb structure 13. Then, on the end surface of the third ceramic honeycomb structure 13, an arbitrary partition wall 131-2 formed from one outer peripheral end to the other outer peripheral end and the optical axis 821 of the laser beam substantially coincide with each other. Place it (Fig. 15 (e)).
When four or more ceramic honeycomb structures are mounted, a desired number of ceramic honeycomb structures can be mounted by repeating (b ₂ ) to (e ₂ ) in the same manner.

  In the above description, an example in which a laser light source is used as the positioning member is shown. However, on the end face of the ceramic honeycomb structure, it is substantially matched with an arbitrary partition formed from one outer peripheral end to the other outer peripheral end. For example, a thread, a string, a steel wire, a light beam, or the like can be used as long as it can be used.

EXAMPLES Hereinafter, although this invention is demonstrated in detail using an Example, this invention is not limited to these Examples.
Cordierite-type ceramic honeycomb structure in which kaolin, talc, silica, and alumina powder are prepared and the mass ratio is SiO ₂ : 48 to 52%, Al ₂ O ₃ : 33 to 37%, MgO: 12 to 15% Prepare body forming ceramic raw material, and add binder of methylcellulose, hydroxypropylmethylcellulose, etc. to ceramic raw material 8%, lubricant and foamed hollow resin pore former with average particle size of 40μm added 7.0% Then, after thoroughly mixing in a dry method, a specified amount of water was added and sufficient kneading was performed to produce a plasticized ceramic clay. Next, the clay is extruded and molded using an extrusion mold having a curved surface (R portion) at the corner of the molding groove, cut to a total length of 300 mm, an outer diameter of 270 mm, and a length of 300 mm. A ceramic honeycomb formed body is prepared and dried by a microwave dryer for 20 minutes to obtain a dried body. Then, the outer peripheral portion of the dried body is processed by changing the inclination of the outer peripheral surface and the partition so that a part or end of 0 to 8 cells of the outer peripheral portion forms the outer peripheral surface. . Then, this dried body was cut into lengths of 150 mm, 75 mm, 37.5 mm, and 25 mm to obtain unfired ceramic honeycomb dried bodies A to L having the number of cells shown in Table 1. Further, this unfired dried body was fired in a firing furnace at a maximum temperature of 1410 ° C. on an 8-day schedule to obtain fired ceramic honeycomb structures A to L.

(Examples 1 and 2)
The unfired honeycomb structure C having a length of 150 mm is placed on the joining device 80, and the two unfired honeycomb structures C are put through the joining material so that the deviation amount shown in Table 2 is obtained. Abutted. The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, the ceramics of Examples 1 and 2 having an outer diameter of 270 mm and an overall length of 300 mm, coated with a slurry made of cordierite, binder, and water on the outer peripheral portion of the ceramic honeycomb structure abutted after firing, and dried. A honeycomb filter was obtained. Two ceramic honeycomb filters were produced.

(Examples 3, 9, and 15)
The unfired honeycomb structure C having a length of 150 mm is placed on the joining device 80, and the two unfired honeycomb structures C are pressed through the joining material so as to have the displacement shown in Table 2. Touched. Cordierite-forming raw materials, binders, and water were used as bonding materials, and they were disposed only on the end surfaces within the range of twice the cell pitch from the outermost periphery of the ceramic honeycomb structure. The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, ceramic honeycomb filters of Examples 3, 9, and 15 having an outer diameter of 266.7 mm and a total length of 301 mm were obtained. Two ceramic honeycomb filters were produced.

(Examples 4, 10, and 16)
The unfired honeycomb structure C having a length of 150 mm is placed on the joining device 80, and the two unfired honeycomb structures C are pressed through the joining material so as to have the displacement shown in Table 2. Touched. Cordierite-forming raw materials, binders, and water were used as bonding materials, and they were disposed only on the end surfaces within the range of twice the cell pitch from the outermost periphery of the ceramic honeycomb structure. The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, a slurry made of cordierite, a binder, and water is coated on the outer peripheral portion of the ceramic honeycomb structure that has been abutted after firing, and after drying, Examples 4, 10, and 16 having an outer diameter of 270 mm and an overall length of 301 mm A ceramic honeycomb filter was obtained. Two ceramic honeycomb filters were produced.

(Examples 5 and 11)
The unfired honeycomb structure D having a length of 150 mm is placed on the joining device 80, and the two unfired honeycomb structures D are pressed through the joining material so as to have the displacement shown in Table 2. Touched. The two honeycomb structures were arranged only on the end face within the range of twice the cell pitch from the outermost periphery of the honeycomb structure using a cordierite forming raw material as a bonding material. The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, a ceramic slurry of Examples 5 and 11 having an outer diameter of 270 mm and an overall length of 301 mm is coated on the outer peripheral portion of the ceramic honeycomb structure abutted after firing with a slurry made of cordierite, a binder, and water and dried. A honeycomb filter was obtained. Two ceramic honeycomb filters were produced.

(Examples 6 and 7)
An unfired honeycomb structure D having a length of 75 mm is placed on the joining device 80, and two unfired honeycomb structures D and two unfired honeycomb structures D are set so as to have the deviation amounts shown in Table 2. A total of four honeycomb structures J were brought into contact with each other through a bonding material. The four honeycomb structures were arranged on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face by using a cordierite forming raw material as a bonding material. The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, a ceramic slurry of Examples 6 to 7 having an outer diameter of 270 mm and an overall length of 303 mm is coated on the outer peripheral portion of the contacted ceramic honeycomb structure after firing with a slurry made of cordierite, a binder, and water. A honeycomb filter was obtained. Two ceramic honeycomb filters were produced.

(Example 8)
An unfired honeycomb structure D having a length of 75 mm is placed on the joining device 80, and a total of four of the unfired two honeycomb structures D and the unfired two honeycomb structures J are obtained. It contact | abutted through the joining material in order of DDJJ. At the time of contact, the displacement amount between the honeycomb structures D and D is 0.1 times the partition wall pitch, and the displacement amount between the honeycomb structures D and J is 0.3 times the partition wall pitch, and the honeycomb structures J and J The amount of deviation between them was 0.1 times the partition wall pitch. Then, the four honeycomb structures were arranged on the end face within the range of twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face, using cordierite forming raw material as a bonding material. . The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, a ceramic honeycomb filter of Example 8 having an outer diameter of 270 mm and an overall length of 303 mm is coated on the outer peripheral portion of the fired ceramic honeycomb structure after contact with a slurry made of cordierite, a binder, and water. Got. Two ceramic honeycomb filters were produced.

(Examples 12 to 13)
An unfired honeycomb structure D having a length of 75 mm is placed on the joining device 80, and two unfired honeycomb structures D and two unfired honeycomb structures D are set so as to have the deviation amounts shown in Table 2. A total of four honeycomb structures I were brought into contact with each other through a bonding material. The four honeycomb structures were arranged on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face by using a cordierite forming raw material as a bonding material. The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, a ceramic slurry of Examples 12 to 13 having an outer diameter of 270 mm and an overall length of 303 mm is coated on the outer peripheral portion of the contacted ceramic honeycomb structure after firing with a slurry made of cordierite, a binder, and water, and after drying. A honeycomb filter was obtained. Two ceramic honeycomb filters were produced.

(Example 14)
An unfired honeycomb structure D having a length of 75 mm was placed on the joining device 80, and a total of four fired honeycomb structures D and two unfired honeycomb structures I were It contact | abutted through the joining material in order of -D-I-I. At the time of joining, the shift amount between the honeycomb structures D and D is an angle of 10 ° with the center of the end face as an axis, and the shift amount between the honeycomb structures D and J is 45 ° with the center of the end face as an axis. The angle and the amount of deviation between the honeycomb structures I and I were 10 ° with the center of the end face as the axis. Then, the four honeycomb structures were arranged on the end face within the range of twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face, using cordierite forming raw material as a bonding material. . The abutted ceramic honeycomb structure was fired at a maximum temperature of 1410 ° C. in a firing furnace on an 8-day schedule. Then, a ceramic honeycomb filter of Example 14 having an outer diameter of 270 mm and an overall length of 303 mm is coated on the outer peripheral portion of the contacted ceramic honeycomb structure after firing with a slurry made of cordierite, a binder, and water, and dried. Got. Two ceramic honeycomb filters were produced.

(Examples 17, 21-22)
The fired honeycomb structure D having a length of 75 mm is placed on the joining device 80, and the four fired honeycomb structures D are pressed through the joining material so as to have the displacement shown in Table 2. Touched. The four honeycomb structures were arranged using cordierite as a bonding material on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face. Then, a slurry made of silica, binder, and water was coated on the outer peripheral portion of the abutted ceramic honeycomb structure, and after drying, Example 17 having an outer diameter of 270 mm and an overall length of 303 mm, an outer diameter of 270 mm and an overall length of 301.5 mm A ceramic honeycomb filter of Example 22 having an outer diameter of 270 mm and an overall length of 307.5 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 18)
The fired honeycomb structure E having a length of 75 mm is placed on the joining device 80, and the four fired honeycomb structures E are pressed through the joining material so as to have the displacement shown in Table 2. Touched. The four honeycomb structures were arranged using cordierite as a bonding material on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face. And the slurry which consists of a silica, a binder, and water was coated on the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, a ceramic honeycomb filter of Example 18 having an outer diameter of 270 mm and a total length of 303 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 19)
The fired honeycomb structure F having a length of 75 mm is placed on the joining apparatus 80, and the four fired honeycomb structures F are pressed through the joining material so as to have the displacement shown in Table 2. Touched. The four honeycomb structures were arranged using cordierite as a bonding material on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face. And the slurry which consists of a silica, a binder, and water was coated to the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, the ceramic honeycomb filter of Example 19 having an outer diameter of 270 mm and an overall length of 303 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 20)
The fired honeycomb structure G having a length of 75 mm is placed on the joining device 80, and the four fired honeycomb structures G are pressed through the joining material so as to have the displacement shown in Table 2. Touched. The four honeycomb structures were arranged using cordierite as a bonding material on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face. And the slurry which consists of a silica, a binder, and water was coated on the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, a ceramic honeycomb filter of Example 20 having an outer diameter of 270 mm and a total length of 303 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 23)
The fired honeycomb structure B having a length of 75 mm is placed on the joining device 80, and the fired honeycomb structures D, H, and J are placed through the joining material so as to have the deviation amounts shown in Table 2. Abutted. The four honeycomb structures were arranged using cordierite as a bonding material on the end face within a range twice the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face. And the slurry which consists of a silica, a binder, and water was coated to the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, the ceramic honeycomb filter of Example 23 having an outer diameter of 270 mm and an overall length of 303 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 24)
The corners of both end faces of the fired honeycomb structures A, B, D, H, I, J, K, and L having a length of 37.5 mm were chamfered by 3 mm. Then, the fired honeycomb structure A is placed on the joining device 80, and the fired honeycomb structures B, D, H, I, J, K, and L are set so as to have the deviation amounts shown in Table 2. A total of 8 pieces were brought into contact with each other through the bonding material. The eight honeycomb structures were arranged using cordierite as a bonding material on the end face within a range of three times the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face. And the slurry which consists of a silica, a binder, and water was coated on the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, a ceramic honeycomb filter of Example 24 having an outer diameter of 270 mm and a total length of 307 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 25)
The corners of both end faces of the fired honeycomb structure D having a length of 25 mm were chamfered by 3 mm. Then, the fired honeycomb structure D was placed on the joining device 80, and the 12 fired honeycomb structures D were brought into contact with each other through the joining material so as to have a deviation amount shown in Table 2. The twelve honeycomb structures were arranged on the end face within a range of three times the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face using cordierite as a bonding material. Then, a slurry made of silica, binder, and water was coated on the outer peripheral portion of the abutted ceramic honeycomb structure, and after drying, a ceramic honeycomb filter of Example 25 having an outer diameter of 270 mm and a total length of 311 mm was obtained (FIG. 8). Two ceramic honeycomb filters were produced.

(Example 26)
The corners of both end faces of the fired honeycomb structure D having a length of 25 mm were chamfered by 3 mm. Then, the fired honeycomb structure D was placed on the joining device 80, and the 13 fired honeycomb structures D were brought into contact with each other through the joining material so as to have a deviation amount shown in Table 2. Thirteen honeycomb structures were arranged on the end face within a range of three times the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end face, using cordierite as a bonding material. And the slurry which consists of a silica, a binder, and water was coated to the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, an Example 26 ceramic honeycomb filter having an outer diameter of 270 mm and an overall length of 337 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 27)
The corners of both end faces of the fired honeycomb structure D having a length of 25 mm were chamfered by 3 mm. Then, the fired honeycomb structure D was placed on the joining device 80, and the 12 fired honeycomb structures D were brought into contact with each other through the joining material so as to have a deviation amount shown in Table 2. Twelve honeycomb structures are arranged using cordierite as a bonding material on the end surface within the range of three times the cell pitch from the outermost periphery of the honeycomb structure and in a cell 3 mm from the end surface. The gaps between them were 3.0 mm, 3.0 mm, 3.0 mm, 3.0 mm, 2.0 mm, 2.0 mm, 2.0 mm, 2.0 mm, 1.0 mm, 1.0 mm and 1.0 mm in order from the upstream side. And the slurry which consists of a silica, a binder, and water was coated to the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, the ceramic honeycomb filter of Example 27 having an outer diameter of 270 mm and a total length of 323 mm was obtained. Two ceramic honeycomb filters were produced.

(Example 28)
The corners of both end faces of the fired honeycomb structure D having a length of 25 mm were chamfered by 3 mm. Then, the fired honeycomb structure D was placed on the joining device 80, and the six fired honeycomb structures D were brought into contact with each other through the joining material so as to have a deviation amount shown in Table 2. The six honeycomb structures are made of cordierite as a bonding material so that the gap between the honeycomb structures is 2 mm, and on the end face within the range of three times the cell pitch from the outermost periphery of the honeycomb structure. An upstream member of the ceramic honeycomb filter of Example 28 was disposed in a cell 3 mm from the end face. Similarly, the fired honeycomb structure D having a length of 25 mm with chamfered corners of both end faces of 25 mm is placed on the joining device 80, and the fired six pieces so as to have the deviation shown in Table 2 are obtained. The honeycomb structure D was brought into contact with the bonding material. The six honeycomb structures are made of cordierite as a bonding material so that the gap between the honeycomb structures is 1 mm, and on the end face within the range of three times the cell pitch from the outermost periphery of the honeycomb structure. Arranged in a cell 3 mm from the end face, a downstream member of the ceramic honeycomb filter of Example 28 was obtained. Then, the upstream member and the downstream member were brought into contact with each other through the bonding material so as to have a deviation amount shown in Table 2. Cordierite is used as the bonding material so that the gap between the upstream member and the downstream member is 3.0 mm, and 3 mm from the end surface within the range of 3 times the cell pitch from the outermost periphery of the honeycomb structure. Placed in the cell. And the slurry which consists of a silica, a binder, and water was coated to the outer peripheral part of the contacted ceramic honeycomb structure, and after drying, the ceramic honeycomb filter of Example 28 having an outer diameter of 270 mm and a total length of 318 mm was obtained. Two ceramic honeycomb filters were produced.

With respect to the ceramic honeycomb filter obtained above, PM collection rate, pressure loss, melt resistance, and clogging due to ash were measured.
The PM collection rate is the carbon collected by the honeycomb filter when carbon powder with a particle size of 0.042μm was added at 3g / h for 2 hours with a fine particle generator at a flow rate of 10Nm ³ / min. The collection rate was calculated from the weight of the powder and the weight of the charged carbon powder. And the collection efficiency is
In the case of 85% or more (◎◎),
70% or more and less than 85% (◎),
50% or more and less than 70% (○),
(△) when 30% or more and less than 50%, and
Less than 30% (×)
The collection efficiency was evaluated as
The pressure loss was evaluated on the pressure loss test stand using the differential pressure between the inlet side and the outlet side of the honeycomb filter when the air flow rate was 7.5 Nm ³ / min as the pressure loss. And the pressure loss is
When exceeding 1.0 kPa (×),
(0.8) when 0.8 kPa and 1.0 kPa
(0.6) when 0.6 kPa and 0.8 kPa
When the pressure is 0.6 kPa or less (◎)
As an initial pressure loss was evaluated. The evaluation results are shown in Table 2.

In the measurement of the PM collection rate, the carbon powder is continuously added to the ceramic honeycomb filter until the fine particles collected in the honeycomb filter become 6 g / L. The sample was mounted on an exhaust test device (not shown), and the carbon powder was ignited by combustion gas from a burner, and the presence or absence of melting damage was confirmed and evaluated. The heating rate at this time is set to 1.6 ° C. per second, and after reaching 600 ° C., the introduction of the combustion gas is stopped and self-combustion with the collected carbon powder is performed. After confirming the presence or absence of internal melting damage by X-rays on the honeycomb filter after the combustion was finished and after cooling, the carbon powder to be collected was 2g / The increase in L was repeated, and the erosion test was repeated until erosion occurred, and the maximum value of the amount of carbon that did not cause erosion was expressed as an index of erosion resistance as the refractory carbon collection. And the index of the erosion resistance is
In case of 20g or more (◎)
Cases of 14g to 18g (○)
In the case of 8g to 12g (△)
For cases of 6g or less (×)
The melt resistance was evaluated. The evaluation results are shown in Table 2.

For evaluation of clogging by ash, the honeycomb filter that has been subjected to the erosion resistance test is cut in a direction parallel to the direction in which the exhaust gas circulates and photographed. Among these, for any 10 cells, the ash deposition amount was calculated as an image area by image analysis, and the ash deposition amount in Comparative Example 1 was relatively evaluated as 100. And, the amount of ash deposited relative to Comparative Example 1,
For cases below 70 (◎)
Cases exceeding 70 and 80 or less (○)
When over 80 and below 90 (△)
When exceeding 90 and 100 or less (×)
As clogging due to ash was evaluated. The evaluation results are shown in Table 2.

A test piece was cut out from the remaining one of the ceramic honeycomb filters produced in each Example, and the porosity, average pore diameter, partition wall end face and partition wall roughness of the ceramic honeycomb structures A to L were measured.
The porosity and average pore diameter were measured by mercury porosimetry. A test piece (10 mm × 10 mm × 10 mm) cut out from the ceramic honeycomb filter was set in a measurement cell of Autopore III manufactured by Micromeritics, and the inside of the cell was decompressed, and mercury was introduced and pressurized. From the relationship between the pressure during pressurization and the volume of mercury pushed into the pores present in the test piece, the relationship between the pore diameter and the cumulative pore volume was determined. The pressure for introducing mercury was 0.5 psi (0.35 × 10 −3 kgf / mm 2), and the constants for calculating the pore diameter from the pressure were a contact angle = 130 ° and a surface tension of 484 dyne / cm. At this time, the porosity was obtained by calculation from the measured value of the total pore volume, assuming that the true specific gravity of cordierite was 2.52 g / cm 3. Then, from the relationship between the pore diameter determined by the mercury intrusion method and the cumulative pore volume, the pore diameter at which the cumulative pore volume is 50% was defined as the average pore diameter of the pores.
The maximum height Rz, which is the roughness of the partition wall end face and the partition wall surface, was measured with a Mitutoyo surface roughness meter SURFTEST over the 2 mm longitudinal direction of the partition wall end face and the partition wall surface using a stylus with a tip radius of curvature of 5 μm. Then, it was obtained according to JIS B 0601-2001, and was taken as the average of the measured values at three locations. These results are shown in Table 3.

(Comparative Examples 1-3)
In Comparative Example 1, a ceramic honeycomb filter described in Patent Document 1 in which the end faces of the cells were alternately plugged was produced and evaluated in the same manner as in the example. A ceramic clay is prepared in the same manner as in the examples, and the clay is extruded using an extrusion mold in which the curved surface (R portion) is not formed at the corner of the forming groove, and the outer diameter is 270 mm and the length is 300 mm. The ceramic honeycomb formed body was prepared and dried with a microwave dryer for 20 minutes to obtain a dried body, and an unfired ceramic honeycomb dried body M having the number of cells shown in Table 1 was obtained. This unfired dried body was fired at a maximum temperature of 1410 ° C. in a firing furnace for 8 days to obtain a fired ceramic honeycomb structure M. The both ends of the cells of this ceramic honeycomb structure were plugged alternately with a plugging material to produce a ceramic honeycomb filter of Comparative Example 1 having an outer diameter of 270 mm and a total length of 300 mm.

  In Comparative Example 2, a ceramic honeycomb filter described in Patent Document 2 in which cells were alternately plugged only on one end face of the ceramic honeycomb structure was produced and evaluated in the same manner as in the example. Plugging was alternately carried out with a plugging material only on one end face of the fired ceramic honeycomb structure M to produce a ceramic honeycomb filter of Comparative Example 2 having an outer diameter of 270 mm and a total length of 300 mm.

  In Comparative Example 3, evaluation was performed in the same manner as in Example 17 except that the amount of deviation was set to 0 in Example 17.

  As shown in Table 2, it can be seen that the ceramic honeycomb filter of the present invention can suppress the pressure loss when the exhaust gas passes while maintaining the PM collection performance, whereas the ceramic of Comparative Example 1 The honeycomb filter has a good PM collection rate, but has a problem in pressure loss. The ceramic honeycomb filters of Comparative Examples 2 and 3 have insufficient PM collection performance.

1: partition wall 2: cell 4: outer peripheral surface 5: outer peripheral wall 6: chamfer 7: R portion 10: ceramic honeycomb filter 11: upstream ceramic honeycomb structure 12: downstream ceramic honeycomb structure 21: bonding material 31: Extrusion die 32: Molding groove 50, 60: Conventional ceramic honeycomb filter 51, 61: Partition walls 52a, 52b, 62a, 62b: Cells 53a, 53b, 63b: Plugging portions 80: Joining device 81: Table 82 83: Laser light source 84, 85: Strut 111: Partition wall of upstream ceramic honeycomb structure 121: Partition wall 821 of downstream ceramic honeycomb structure, 831: Optical axis X, Y of laser beam: Plurality of ceramic honeycomb structures Partition space θ between the partition walls: partition wall angles A ₀₁ , A ₁₁ , A ₂ between the partition walls of the plurality of ceramic honeycomb structures ₁ , A ₃₁ , A ₄₁ : Cell opening area in the upstream ceramic honeycomb structure A ₀₂ , A ₁₂ , A ₂₂ , A ₃₂ , A ₄₂ : Cells reduced by the partition walls of the joined downstream ceramic honeycomb structure Opening area R ₁ : radius of curvature of one opposite corner of the cell R ₂ : radius of curvature of the other opposite corner of the cell

Claims (17)

A ceramic honeycomb filter for removing fine particles in exhaust gas, wherein a plurality of ceramic honeycomb structures having cells partitioned by porous partition walls flow in the exhaust gas at the end face of the ceramic honeycomb structure. The plurality of ceramic honeycomb structures are bonded to each other in such a manner that at least some of the partition walls of the plurality of ceramic honeycomb structures are displaced from each other in a cross section perpendicular to the direction in which the exhaust gas flows. Further, in the cells of the upstream ceramic honeycomb structure through which the exhaust gas of the plurality of ceramic honeycomb structures flows, the cell opening area A ₀₁ in the cross section perpendicular to the exhaust gas flowing direction and the cell opening area A ₀₁ of the cell are Cell opening area A reduced by partition walls of bonded downstream ceramic honeycomb structure _The cell opening area ratio A ₀ = (A ₀₂ / A ₀₁ ), which is the ratio of ₀₂ , is an average value of 0.9 or less in an arbitrary 5 cells × 5 cells = 25 cells, and the downstream ceramic honeycomb structure A ceramic honeycomb filter having a partition wall end surface roughness (maximum height Rz) of 15 μm or more and a partition wall surface roughness (maximum height Rz) of 15 μm or more. The absolute value of the difference between the cell opening area ratio (A ₀ ) in the cell and the cell opening area ratio (A ₁ , A ₂ , A ₃ , A ₄ ...) In the cell adjacent to the cell is arbitrary. 2. The ceramic honeycomb filter according to claim 1, wherein a maximum value of 5 cells × 5 cells = 25 cells is 0.10 or more and less than 1.0. The partition walls of the plurality of ceramic honeycomb structures are bonded to each other with a shortest distance between the partition walls in the direction of the partition wall thickness being shifted by 0.1 times or more and less than 0.5 times the partition wall pitch. The ceramic honeycomb filter according to claim 2. The partition walls of the plurality of ceramic honeycomb structures are joined at positions shifted by an angle of 35 to 55 ° with the center of the end face as an axis. A ceramic honeycomb filter as described in 1. The ceramic honeycomb filter according to any one of claims 1 to 4, wherein the plurality of ceramic honeycomb structures is 2 or more and 15 or less. In the cross section orthogonal to the direction in which the exhaust gas flows, the cell has a substantially quadrangular shape, the corners are arcuate, and the radius of curvature of one opposing corner is greater than the radius of curvature of the other opposing corner. The ceramic honeycomb filter according to any one of claims 1 to 5, wherein the ceramic honeycomb filter is provided. The ceramic honeycomb filter according to any one of claims 1 to 6, wherein an interval between the end faces of the plurality of bonded ceramic honeycomb structures is 0.01 to 3.0 mm. The ceramic honeycomb filter according to any one of claims 1 to 7, wherein an opening ratio of the plurality of ceramic honeycomb structures is 75% or less. 9. The ceramic honeycomb filter according to claim 8, wherein the plurality of ceramic honeycomb structures are joined such that adjacent ceramic honeycomb structures have different aperture ratios. In the plurality of ceramic honeycomb structures, in the cross section parallel to the direction in which the exhaust gas flows, adjacent partition walls are substantially parallel to each other, and 1 to 5 cells in the outer peripheral portion of the ceramic honeycomb structure are The ceramic honeycomb filter according to any one of claims 1 to 9, wherein a part or an end of the cell forms an outer peripheral surface.   A method for manufacturing a ceramic honeycomb filter in which a plurality of ceramic honeycomb structures are joined, wherein a ceramic clay is extruded into a honeycomb shape, cut into a predetermined length, and a plurality of dried ceramic honeycomb bodies are dried. A method for manufacturing a ceramic honeycomb filter, comprising: placing a plurality of ceramic honeycomb dried bodies on the end face of the ceramic honeycomb dried body by shifting the partition walls; and firing the plurality of ceramic honeycomb dried bodies to form a plurality of ceramic honeycomb structures .   The method for manufacturing a ceramic honeycomb filter according to claim 11, wherein after the firing, a coating material is applied to an outer peripheral portion of the plurality of ceramic honeycomb structures.   A method for manufacturing a ceramic honeycomb filter in which a plurality of ceramic honeycomb structures are joined, wherein a ceramic clay is extruded into a honeycomb shape, cut into a predetermined length, and a plurality of dried ceramic honeycomb bodies are dried. Production of a ceramic honeycomb filter characterized in that, on the end face of the dried ceramic honeycomb body, the partition walls are shifted from each other, a coating material is applied to the outer peripheral portion of the plurality of dried ceramic honeycomb bodies, and fired Method.   A method for manufacturing a ceramic honeycomb filter in which a plurality of ceramic honeycomb structures are joined, wherein the ceramic clay is extruded into a honeycomb shape, cut into a predetermined length, dried and fired, and then the plurality of ceramic honeycomb structures On the end face of the ceramic honeycomb structure, the partition walls are shifted from each other, and a coating material is applied to the outer periphery of the plurality of ceramic honeycomb structures placed above, .   The bonding material is disposed at a peripheral edge portion of the end face of the ceramic honeycomb structure, and the plurality of ceramic honeycomb structures are placed via the bonding material. A method for producing a ceramic honeycomb filter according to claim 1.   On the end face of one ceramic honeycomb structure of the plurality of ceramic honeycomb structures, after substantially aligning a positioning member to an arbitrary partition formed from one outer peripheral end to the other outer peripheral end, One ceramic honeycomb structure moved in the X direction or Y direction, or moved in both the X direction and the Y direction, or rotated around the center of the end face, and moved. When placing another ceramic honeycomb structure on the end face of the structure, positioning is performed on an arbitrary partition wall formed from one outer peripheral end to the other outer peripheral end on the end face of the other ceramic honeycomb structure. 16. The structure according to claim 11, wherein the members are placed so as to be substantially coincident with each other so that the partition walls are shifted from each other. Method for producing a ceramic honeycomb filter crab according. The method for manufacturing a ceramic honeycomb filter according to claim 16, wherein the positioning member is a linear member made of a metal and / or a non-metal, or a light beam.

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