JP5280922B2 - Plugged honeycomb structure and diesel particulate filter using the same - Google Patents

Description

  The present invention relates to a honeycomb structure and a diesel particulate filter using the honeycomb structure. More specifically, while having improved erosion resistance, it has an end shape that equalizes the distribution of thermal stress during DPF regeneration, problems of wear and strength reduction during production, reduction of regeneration limit during DPF regeneration, pressure The present invention relates to a plugged honeycomb structure in which problems such as an increase in loss are also improved, and a diesel particulate filter using the plugged honeycomb structure.

  Conventionally, a catalyst carrier utilizing catalytic action such as an internal combustion engine, a boiler, a chemical reaction device, and a reformer for a fuel cell, and a filter for collecting particulates in exhaust gas, particularly diesel particulates (diesel particulate filter: In some cases, a honeycomb structure made of ceramics is used.

  A honeycomb structure used for such a purpose generally has a plurality of cells serving as fluid flow paths partitioned by porous partition walls, and particularly when used as a particulate collection filter, the end face Has a structure in which adjacent cells are plugged at opposite ends so that a checkered pattern is formed. In the honeycomb structure having such a structure, the fluid to be treated flows into a cell in which the end surface on the inflow hole side is not sealed, that is, a cell in which the end surface on the outflow hole side is sealed, and passes through the porous partition wall. It discharges | emits from the cell by which the adjacent cell, ie, the inflow hole side end surface, is sealed, and the outflow hole side end surface is not sealed. At this time, the partition wall serves as a filter, and for example, when used as a DPF, particulate matter (particulate matter: hereinafter referred to as “PM”) such as soot discharged from a diesel engine is separated from the partition wall. And is deposited on the partition wall.

  In a diesel engine, the honeycomb structure as described above is usually disposed as a DPF in the exhaust gas flow path on the downstream side of the engine, and functions to pass and purify the exhaust gas discharged from the engine. At this time, the rust on the inner wall of the flow passage that flows from the upstream side of the exhaust gas, welding debris, solids such as dust that entered the flow passage when the DPF is assembled, or liquid such as condensed water, together with the exhaust gas, at high speed By colliding with the inner wall of the flow passage or the honeycomb structure disposed in the flow passage, these may be worn out. FIG. 3 is a perspective view schematically illustrating a problem with such a conventional plugged honeycomb structure. For example, when the region A, which is the edge of the inflow hole side end face 11 in FIG. 3, is disposed below such that the axial direction 8 of the DPF is lateral, particularly solid foreign matter is caused by the engine vibration due to engine vibration. Since it bounces at the side end face, it may go through the plugged portion of the lower portion such as the region A of the DPF, leading to a decrease in collection efficiency. This action is usually called erosion, and has been a serious problem from the viewpoint of maintaining the long-term durability of the flow passage and the honeycomb structure.

  In order to solve the erosion problem, conventionally, a metal net or a baffle plate has been provided on the inner wall of the flow passage which may be subject to wear or on the upstream side of the honeycomb structure to prevent foreign matter from directly colliding at high speed. Solid or liquid foreign matter could not be removed to a sufficient level, and there was a problem in long-term durability. That is, the foreign matter flying from the upstream side of the exhaust gas flow may cause damage to the inner wall surface of the flow passage or wear of the honeycomb structure. Thus, there is a need for a device that can more reliably prevent wear caused by foreign matter in the flow passage and enhance the durability of the purification device. For example, Patent Document 1 discloses a method for improving the flow passage on the upstream side of the honeycomb structure. In addition, a flow passage provided with exhaust gas flow changing means and a foreign matter collecting part is disclosed.

JP-A-9-206526

  The gas flow passage disclosed in Patent Document 1 has an opening facing the upstream direction of the exhaust gas, which is installed on the inner wall of the flow passage, with the exhaust gas flow changing means directing the flow of the exhaust gas toward the outer periphery of the flow passage. The pocket-shaped foreign matter collecting part physically collects foreign matter in the exhaust gas, and is effective against the erosion problem caused by foreign matter splashing in the flow passage. There is a problem that the entire exhaust gas purification device becomes large. In addition, if the pocket is attached without changing the flow passage diameter, the flow passage cross section becomes smaller and pressure loss increases, and there is a concern that the engine output may decrease.If the pocket is made with a larger flow passage diameter, the flow passage cross section becomes larger. In order to secure the minimum ground clearance when mounted under the vehicle floor, the vehicle height must be raised. Considering that the space for mounting on the vehicle body is limited, it is desirable that the exhaust gas purification device be designed as small as possible, and the flow passage disclosed in Patent Document 1 is not sufficient in that sense.

  The present invention has been made in view of the problems of the prior art, and the problem is that the present invention is used in an exhaust gas purification apparatus that achieves both an erosion suppressing effect and a size reduction, and purification performance and strength by shape processing. It is an object of the present invention to provide a plugged honeycomb structure in which a decrease in the above is suppressed, and which is excellent in terms of raw material yield and cost, and a DPF using the plugged honeycomb structure.

  As a result of diligent studies to solve the above problems, the present inventors have a plurality of cells serving as fluid flow paths partitioned by porous partition walls, and one end portion where adjacent cells are opposite to each other. In the plugged honeycomb structure in which a plurality of adjacent honeycomb segments are integrally bonded via a bonding material layer, the plugged honeycomb structure is formed on the end surface of the fluid inflow hole. By adopting a configuration in which the inclined segment has at least a part of an inclined surface inclined so as to reduce the axial length of the plugged honeycomb structure from the center side to the outer peripheral side of the body, The present inventors have conceived that a cut-out portion having an inclined surface can effectively save space corresponding to the volume of the cut-out portion while effectively working to suppress erosion.

  Furthermore, the present inventors are assumed to be caused by forming a notch in the plugged honeycomb structure, such as a decrease in regeneration limit and an increase in pressure loss at the time of DPF regeneration due to turbulent flow of the inflowing gas. We have also studied various problems and conceived that turbulent flow of the inflowing gas at the notch can be suppressed and solved by providing a rectifying action with at least a part of the shape of the notch as an inclined surface. Completed the invention. That is, according to the present invention, a plugged honeycomb structure having sufficient purification performance and strength and having a desired end face shape and a DPF using the plugged honeycomb structure, that is, the following plugged honeycomb structure and the following are used. DPF was provided.

[1] A plurality of cells having a plurality of cells that serve as fluid flow paths partitioned by porous partition walls, and the adjacent cells are plugged at one end opposite to each other. A plugged honeycomb structure for a diesel particulate filter in which a plurality of the honeycomb segments are adjacent to each other, and are integrally bonded to each other at a bonding surface between the adjacent honeycomb segments via a bonding material layer, At least a part of the honeycomb segment arranged on the outer peripheral side of the plugged honeycomb structure is directed to the end surface on the fluid inflow hole side from the central side of the plugged honeycomb structure to the outer peripheral side. the axial length of the plugged honeycomb structure is a ramp segment having at least a portion inclined inclined surface so as to reduce Te, the inclined surface A plugged honeycomb structure provided on a part of the outer peripheral portion of the plugged honeycomb structure.

[2] The plugged honeycomb structure according to [1], wherein one or more inclined segments are provided adjacent to each other.

[3] The inclination start position where the inclined surface starts is formed on the joining surface, and the distance from the inclination starting position to the outer peripheral wall of the honeycomb structure along the joining surface where the inclination starting position is formed The plugged honeycomb structure according to the above [1] or [2], wherein the ratio H / L between L and the height H of the inclined surface is in the range of 0.05 to 1.5.

[4] The inflow hole side end surface of the inclined segment includes the inclined surface and a flat surface, and the flat surface is provided on the center side of the plugged honeycomb structure, and the inclined surface is the outer peripheral portion. The plugged honeycomb structure according to any one of [1] to [3], provided on a side.

[5] The inflow hole side end surface of the inclined segment includes the inclined surface and a flat surface, the flat surface is provided on the outer peripheral portion side, and the inclined surface is provided on the central portion side. ] The plugged honeycomb structure according to any one of [3] to [3].

[6] The plugged honeycomb structure according to any one of [1] to [5], wherein the inclined surface has a streamline shape for rectifying the fluid.

[7] The plugged honeycomb structure according to [6], wherein the inclined surface is a concave curved surface that is retracted toward the outflow hole.

[8] The plugged honeycomb structure according to [6], wherein the inclined surface is a convex curved surface protruding in the direction of the end surface on the inflow hole side.

[9] A diesel particulate filter in which the plugged honeycomb structure according to any one of [1] to [8] is loaded with a catalyst component for exhaust gas purification.

[10] The method for manufacturing a plugged honeycomb structure according to any one of [1] to [8], wherein the plugged depth corresponding to the inclined surface, which is to be the inclined segment After bonding the honeycomb segment in which the long plugging portion is formed to the flat segment in which the plugging portion having a depth smaller than the long plugging portion is formed and having the same axial length, A method for manufacturing a plugged honeycomb structure in which a plugged honeycomb structure having the inclined surface is formed by cutting an end portion on the long plugged portion forming side of the honeycomb segment according to the shape of the inclined surface.

[11] The method for manufacturing a plugged honeycomb structure according to any one of [1] to [8], wherein an inclined segment having the inclined surface on the flat segment having an equal axial length in advance is provided. A method for manufacturing a plugged honeycomb structure in which a plugged honeycomb structure having a notch with the inclined surface is formed by joining to the flat segment.

  The plugged honeycomb structure of the present invention and the DPF using the same form a notch having an inclined surface at the end surface on the fluid inflow hole side as a measure against erosion, and the turbulent flow of the inflowing gas by the rectifying action of the inclined surface And has an end shape that equalizes the distribution of thermal stress at the time of DPF regeneration by preventing the uneven deposition distribution of PM at the notch due to gas turbulence, increasing pressure loss, DPF Problems such as lowering of the reproduction limit during reproduction can be improved.

1 is a perspective view schematically showing an embodiment of a plugged honeycomb structure of the present invention. 1 is a partially enlarged perspective view schematically showing one embodiment of an inclined segment having an inclined surface of a plugged honeycomb structure of the present invention. FIG. 3 is a partially enlarged perspective view schematically showing another embodiment of an inclined segment having an inclined surface of the plugged honeycomb structure of the present invention. It is a perspective view which shows typically one Embodiment of the conventional plugged honeycomb structure. It is a perspective view which shows typically an example of the plugged honeycomb structure which has a notch part. 1 is a cross-sectional view schematically showing an embodiment of an exhaust gas purification apparatus equipped with a plugged honeycomb structure of the present invention. It is sectional drawing which shows typically another embodiment of the exhaust gas purification apparatus carrying the plugged honeycomb structure of this invention. [Fig. 6] Fig. 6 is a cross-sectional view schematically showing still another embodiment of an exhaust gas purifying apparatus equipped with a plugged honeycomb structure of the present invention. It is sectional drawing which shows typically a mode that waste gas flows into an example of the plugged honeycomb structure which has a flat notch part. FIG. 3 is a partially enlarged cross-sectional view of the periphery of a notch portion schematically showing how exhaust gas flows into an example of a plugged honeycomb structure having a flat notch portion. It is sectional drawing which shows typically a mode that waste gas flows into other embodiment of the plugged honeycomb structure of this invention. It is a partially expanded sectional view along the joining surface for demonstrating the dimension of the inclination segment which has the inclined surface of the plugged honeycomb structure of this invention. 1 is a schematic cross-sectional view showing an embodiment of an inclined surface of a cutout portion of a plugged honeycomb structure of the present invention. 1 is a schematic cross-sectional view showing an embodiment of an inclined surface of a cutout portion of a plugged honeycomb structure of the present invention. 1 is a schematic cross-sectional view showing an embodiment of an inclined surface of a cutout portion of a plugged honeycomb structure of the present invention. 1 is a schematic cross-sectional view showing an embodiment of an inclined surface of a cutout portion of a plugged honeycomb structure of the present invention. 1 is a schematic cross-sectional view showing an embodiment of an inclined surface of a cutout portion of a plugged honeycomb structure of the present invention. 1 is a schematic cross-sectional view showing an embodiment of an inclined surface of a cutout portion of a plugged honeycomb structure of the present invention. It is a fragmentary sectional view in the direction of an axis showing typically a plugged honeycomb structure before cutting a long plugged part formation side edge part. It is a fragmentary sectional view in the direction of an axis showing typically a plugged honeycomb structure after cutting a long plugged part formation side edge part. 1 is a schematic front view of an embodiment of a plugged honeycomb structure of the present invention as viewed from a notch formation direction. It is the typical front view which looked at another embodiment of the plugged honeycomb structure of this invention from the notch part formation direction. It is process drawing which shows the process which piles up a honeycomb segment typically. 1 is a perspective view schematically showing an embodiment of a honeycomb segment laminate.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The present invention is not limited to the following embodiments, and changes, modifications, and improvements can be added without departing from the scope of the invention.

  FIG. 1 is a perspective view schematically showing an embodiment of the plugged honeycomb structure of the present invention, and FIG. 2A shows one of the inclined segments having the inclined surfaces of the plugged honeycomb structure of the present invention. It is a partial expansion perspective view showing an embodiment typically. FIG. 2B shows another implementation of the inclined segment in the plugged honeycomb structure of the present invention having an inclined surface with the depth D from the end surface on the inflow hole side of the plugged honeycomb structure as an inclination start position. It is a partially expanded perspective view which shows a form typically. FIG. 3 is a perspective view schematically showing a conventional plugged honeycomb structure.

  Conventionally, as a plugged honeycomb structure used as a DPF in an exhaust gas purification apparatus, for example, as shown in FIG. 3, a honeycomb segment having a plurality of cells 5 serving as fluid flow paths partitioned by porous partition walls 6 is used. A plurality of (flat segments 1b) are integrally bonded via the bonding material layer 3 and formed into a desired shape, and then the adjacent cells 5 are plugged at the flow ends opposite to each other, A cylindrical plugged honeycomb structure 150 having no irregularities at its eight axial ends is used, such as a plugged honeycomb structure 150 in which the plugged portions 25 are formed.

  In the present specification, the axial direction 8 of the plugged honeycomb structure refers to the central axis direction of the plugged honeycomb structure from the inflow hole side end surface to the outflow hole side end surface of the plugged honeycomb structure. Say.

  As the plugged honeycomb structure of the present invention, for example, as shown in FIG. 1, the plugged honeycomb structure has a plurality of cells 5 serving as fluid flow paths partitioned by porous partition walls 6, and adjacent cells 5 are mutually connected. A plurality of honeycomb segments 1 (1a, 1b) in which plugged portions 25 plugged at one end on the opposite side are formed are integrally bonded via a bonding material layer 3 to have a desired shape. The plug-type honeycomb structure 100 of the joining type formed in the above has a notch portion 2 having an inclined surface 7 on a part of the end surface 11 on the fluid inflow hole side to constitute the notch portion 2. Also in the predetermined cell 5, there is a plugged honeycomb structure 100 in which adjacent cells 5 are plugged at one end opposite to each other. And this inclined surface 7 inclines so that the length of the axial direction 8 of a plugged honeycomb structure may decrease toward the outer peripheral part side from the center part side of a plugged honeycomb structure.

  FIG. 2A is a partially enlarged perspective view schematically showing the cutout portion 2 of the inclined segment 1 a having the inclined surface 7. By providing the inclined surface 7, it has a rectifying action of exhaust gas and prevents the occurrence of turbulent flow, thereby preventing the pressure loss from decreasing and the occurrence of cracks during regeneration processing due to the uneven distribution of PM deposition distribution. it can.

  FIG. 9 is a partially enlarged cross-sectional view along the joining surface for explaining the dimensions of the inclined segment having the inclined surface of the plugged honeycomb structure of the present invention. In the plugged honeycomb structure of the present invention, for example, as shown in FIG. 9, when the inclination start position 40 where the inclined surface starts is formed on the joining surface, the inclination start position 40 is formed from the inclination start position. The ratio H / L of the distance L to the outer peripheral wall of the honeycomb structure along the bonding surface and the height H of the inclined surface is preferably in the range of 0.05 to 1.5. In the DPF in which the exhaust gas purification catalyst is supported on the plugged honeycomb structure, the catalyst only slightly increases the size in the honeycomb wall thickness direction. The H / L regulations are all valid for the DPF after supporting the catalyst.

  The overall shape of the plugged honeycomb structure 100 of the present invention is a desired shape such as a cylindrical shape or an oval shape suitable as an exhaust gas purification filter, and has an inclined surface 7 on the end surface on the fluid inflow hole side. It can be set as the shape which has the notch part 2. FIG. In the plugged honeycomb structure 100 of the present invention, the notch 2 and the inclined surface 7 thereof are formed in a desired position and a desired size according to the application and purpose, and at the same time, the inflow including the notch 2. A predetermined cell 5 is plugged in the entire end surface on the hole side, and a decrease in purification performance due to shape processing is suppressed. The cutout portion 2 having the inclined surface 7 is preferably provided as an inclined segment in units of honeycomb segments constituting the outer peripheral portion of the plugged honeycomb structure 100.

  The material of the honeycomb segment 1 constituting the bonded and plugged honeycomb structure 100 is preferably ceramic, and silicon carbide, silicon-silicon carbide based composite material, cordierite, mullite, alumina, spinel, silicon carbide. -It is preferable that it is at least 1 sort (s) selected from the group which consists of a cordierite type composite material, lithium aluminum silicate, an aluminum titanate, and an iron-chromium-aluminum type alloy. In particular, among these materials, silicon carbide or silicon-silicon carbide based composite material suitable for DPF in terms of high melting point and excellent heat resistance is preferably used. Silicon carbide has a relatively large coefficient of thermal expansion among the above materials. For this reason, when the honeycomb structure formed using silicon carbide as an aggregate has a large outer diameter, the honeycomb structure may have defects due to thermal shock during use. In the structure bonded integrally through the material layer 3, the expansion and contraction of silicon carbide is buffered by the bonding material layer 3, and the occurrence of defects in the honeycomb segment 1 can be prevented.

  Moreover, as a material for the bonding material layer 3, a material in which a filler such as inorganic fiber, colloidal silica, clay, SiC particles, an organic binder, and a foamed resin is dispersed in a dispersion medium such as water is used. it can.

  5A to 5C are cross-sectional views schematically showing embodiments of the exhaust gas purifying apparatus equipped with the plugged honeycomb structure of the present invention. 5A and 5B, the left side in the figure is the exhaust gas inflow hole side end face, and the right side in the figure is the exhaust gas outflow hole side. In the exhaust gas purifying apparatus 110 shown in FIG. 5A, the plugged honeycomb structure 100 in which the notch portion 2 having an inclined surface is formed is installed as the DPF 18 at the subsequent stage of the honeycomb catalyst body 9 in the container 15. At this time, in the DPF 18, the notch 2 having an inclined surface faces the upstream side of the exhaust gas flow when the exhaust gas purification device is mounted on the vehicle body, and faces the lower side (ground side) of the exhaust gas purification device 110. It is preferable to be positioned as described above.

  The solid or liquid foreign matter flowing from the upstream side of the exhaust gas flow descends to the lower side of the exhaust gas purification device 110 according to gravity. Therefore, damage tends to concentrate particularly on the inner wall of the container 15 and the end surface 11 on the inflow hole side of the DPF 18. By installing the DPF 18 with the notch 2 facing downward, a space for allowing foreign matter to bounce at the bottom of the container 15 is created, reducing the frequency of foreign matter directly colliding with the end surface of the DPF 18 and reducing the impact at the time of collision. There is an effect to. That is, if the plugged honeycomb structure 100 of the present invention is used, the durability deterioration due to erosion can be prevented even if an extra facility such as a wire mesh or a foreign matter collecting pocket is not provided on the flow path of the exhaust gas purifying device as in the prior art. Therefore, it is possible to realize space saving and cost saving in the exhaust gas purification apparatus.

  In the exhaust gas purifying apparatus 120 shown in FIG. 5B, the structure 100 having the notched portion 2 having the inclined surface 7 is installed as the DPF 18 at the subsequent stage of the honeycomb catalyst body 9 of the container 15. In addition, a foreign matter collecting pocket 13 is provided for collecting foreign matter that flows from upstream and causes wear of the DPF 18, and the notch 2 of the DPF 18 functions as a guide path for letting the foreign matter escape to the foreign matter collecting pocket 13. ing. By adopting such a configuration, it is possible to collect a large amount of foreign matter flowing into the foreign matter collecting pocket 13 without colliding with the inflow hole side end surface 11 of the DPF 18. At this time, like the exhaust gas purification device 110 shown in FIG. 5A, the DPF 18 has the notch 2 facing the upstream side of the flow of exhaust gas when the exhaust gas purification device 120 is mounted on the vehicle body, and the bottom of the exhaust gas purification device 120. It is preferable to be positioned to face the side (ground side).

  Further, the plugged honeycomb structure 100 of the present invention not only exhibits an erosion suppressing effect in a limited space, but also can be applied to a specially shaped container 15 as shown in FIG. 5C. Have advantages. For example, when the space that can be used is limited, such as at the bottom of the vehicle body, the exhaust gas purification device itself is designed to be small, and at the same time, no dead space is generated around the exhaust gas purification device after being mounted on the vehicle body. This is an effective measure. In other words, when the exhaust gas purification device is mounted on the vehicle body, if the container shape of the exhaust gas purification device is deformed in advance according to the space shape of the mounting location, no wasteful space is generated and the limited space is maximized. However, for this purpose, a honeycomb structure having a shape corresponding to the container shape is required, and the plugged honeycomb structure 100 of the present invention is preferably used.

  FIG. 4 is a perspective view schematically showing an example of a plugged honeycomb structure having a flat cutout 2 having no inclined surface. FIG. 6 is a cross-sectional view schematically showing how exhaust gas flows into an example of a plugged honeycomb structure 151 having notches 2 as shown in FIG. 4, and FIG. It is sectional drawing which shows typically a mode that exhaust gas flows into one Embodiment of a stop honeycomb structure. Thus, by providing the notch part 2, the problem of erosion can be avoided. However, at this time, in the plugged honeycomb structure 151 shown in FIG. 6, a turbulent flow is generated in the exhaust gas by the end portion of the cutout portion 2, and the corner portion 14 of the cutout portion 2 is avoided. Since it flows, in FIG. 6, it becomes difficult for exhaust gas to flow into the cell located below the corner 14 of the notch 2. Therefore, the PM deposition on the partition walls of the cell 5 is reduced, and the PM deposition amount in the short segment 1c may be non-uniform. In severe operation, where the amount of accumulated PM is expected to increase, when the accumulated PM is burned and the filter is regenerated, the uneven thermal stress caused by the difference in the amount of accumulated PM leads to the generation of cracks. May lead to

  FIG. 7 is a partially enlarged cross-sectional view of the periphery of the notch portion, showing how cracks are generated around the notch portion 2 in FIG. 6 when the DPF regeneration process is performed. As shown in FIG. 7, in the cutout portion 2, there is little accumulation of PM in the porous partition wall between the flat segment 1 b and the short segment 1 c, causing a temperature imbalance during the DPF regeneration process. It becomes. Further, at this time, cracks 50 are generated due to uneven distribution of thermal stress generated in the region 51 not in contact with the short segment 1c and the region 52 in contact with the short segment 1c having the notch portion through the bonding material layer 3. Conceivable.

  However, the provision of the inclined surface 7 in the notch 2 as shown in FIG. 8 gives the exhaust gas rectification action, and the occurrence of exhaust gas turbulence and the accompanying PM deposition distribution are non-uniform. It can be suppressed. For this reason, the uneven distribution of thermal stress between the flat segment and the 1b inclined segment 1a and the occurrence of cracks associated therewith can be prevented. By adopting such a design, it is possible to minimize the reduction of the filter area, adjust the uneven distribution of soot deposition due to the turbulent flow of exhaust gas during use, and suppress an increase in pressure loss.

  As shown in FIGS. 11 and 12, a bonded plugged honeycomb structure 100 in which a plurality of honeycomb segments 1 (1a, 1b) of the present invention are integrally bonded through a bonding material layer 3 is as shown in FIGS. The honeycomb segment 1 in which the long plugging portion 24 scheduled to be the inclined segment 1a is joined to the flat segment 1b in which the plugging portion 25 having a depth smaller than that of the long plugging portion 24 is formed. Then, it can manufacture by cutting the long sealing part formation side edge part of the honeycomb segment 1 in the shape corresponding to a desired inclined surface. FIG. 11 is a partial cross-sectional view in the axial direction schematically showing the plugged honeycomb structure before cutting the end portion of the long plug portion forming side, and FIG. 12 shows the end portion of the long plug portion forming side. FIG. 3 is a partial cross-sectional view in the axial direction schematically showing a plugged honeycomb structure after cutting. In FIG.11 and FIG.12, although the plugging part 25 in the edge part opposite to a notch part formation plan side was abbreviated from the figure on account of drawing, in any honeycomb segment 1 (1a, 1b), Adjacent cells 5 are plugged at the flow end portions opposite to each other, and the plugged portion depth by the honeycomb segment 1 (1a, 1b) is formed at the end portion opposite to the notch forming scheduled side. There is no difference, and the plugged portion 25 having a certain depth is formed.

  In order to form the plugged portion, first, a mask tape is attached to one end surface of the honeycomb segment 1 after drying (the end surface on the side where the cutout portion is scheduled to be formed), and only at the portion where the plugged portion is to be formed With respect to what becomes a flat segment 1b by opening a hole with a laser, the end of the honeycomb segment 1 on the masked side is immersed in a plugging slurry having a depth in the range of 0.5 to 2.0 mm, A plugging portion 25 is formed. As for the inclined segment 1a, in the same manner as the flat segment 1b, the end of the honeycomb segment 1 on the masked side is dipped in a plugging slurry having a predetermined depth, and the long segment is sealed. A stop 24 is formed. At this time, the depth of the plugging slurry to be immersed can be appropriately determined according to the depth of the notch 2 of the plugged honeycomb structure to be obtained and the gradient of the inclined surface 7.

  Further, in any honeycomb segment 1, the mask tape is also applied to the other end surface (the end surface opposite to the notch forming side) so that the adjacent cells 5 are plugged at the flow end portions on the opposite side. And a hole is formed by a laser only at a place where the plugging portion is to be formed, and the end portion is immersed in a plugging slurry having a depth in the range of 0.5 to 2.0 mm. A portion 25 is formed. Next, the honeycomb segments 1 are stacked according to a desired number and combination, joined to each other so that both ends of the honeycomb segments 1 are aligned, and then pressed and dried to obtain a honeycomb segment laminate 30 (see FIG. 16). . At this time, from the viewpoint of forming the cutout portion 2 for suppressing erosion, the honeycomb segment 1 that becomes the inclined segment 1a is formed in the honeycomb segment laminated body 30 so that the inclined segment 1a forms the corner of the honeycomb structure. It is preferable to arrange at a corner (see FIG. 13). Moreover, when forming the notch part 2 with the some inclination segment 1a, it is preferable that the some honeycomb segment 1 used as the inclination segment 1a is arrange | positioned so that it may mutually adjoin (refer FIG. 14). FIG. 13 is a schematic front view of one embodiment of the plugged honeycomb structure of the present invention viewed from the notch formation direction, and FIG. 14 shows another plugged honeycomb structure of the present invention. It is the typical front view which looked at this embodiment from the notch part formation direction. In FIG. 13 and FIG. 14, the cells 5, the partition walls 6, and the plugging portions 25 are omitted from the drawings for the convenience of drawing.

  Next, the obtained honeycomb segment laminated body 30 is subjected to outer peripheral processing as necessary, and the formation side end portion (notched portion formation planned portion) of the honeycomb segment 1 in which the long plug portions 24 are formed is formed in a desired shape. The inclined segment 1a having the plugging portions 27 is formed by cutting with an end mill 26 in a shape corresponding to the inclined surfaces 7 so that the long plugging portions 24 remain at a predetermined depth, and a desired inclined surface is formed. A plugged honeycomb structure 100 having 7 is obtained. In such a manufacturing method, since the technique in the manufacturing method of the conventional plugged honeycomb structure 103 can be used until joining and outer periphery processing, it is preferable. Further, as shown in FIGS. 13 and 14, it is preferable to provide the outer peripheral wall 41 after the outer periphery processing is performed on the honeycomb segment laminated body 30 (see FIG. 16) for improving the strength.

  Further, in a joint type plugged honeycomb structure 100 in which a plurality of honeycomb segments 1 (1a, 1b) are integrally joined via a joining material layer 3, an inclined surface 7 is previously formed as the inclined segment 1a. The inclined segment 1a thus formed can be manufactured by joining to the flat segment 1b and processing the outer periphery thereof as necessary.

  First, a joining material is applied to each joining surface of the inclined segment 1a and the flat segment 1b on which the inclined surface 7 has been prepared in advance, and sequentially stacked according to a desired number and combination (see FIG. 15), opposite to the notch formation scheduled side. After joining them so that their end faces are aligned, pressurization and drying are performed to obtain a honeycomb segment laminate 30 (see FIG. 16). At this time, from the viewpoint of forming the cutout portion 2 for suppressing erosion, the inclined segment 1a is arranged at the corner of the honeycomb segment laminated body 30 so that the inclined segment 1a constitutes a corner portion of the honeycomb structure 106. It is preferable (see FIG. 13). Moreover, when forming the notch part 2 with the some inclination segment 1a, it is preferable that the some inclination segment 1a is arrange | positioned so that it may mutually adjoin (refer FIG. 14). FIG. 15 is a process diagram schematically showing the process of stacking the honeycomb segments, and FIG. 16 is a perspective view schematically showing one embodiment of the honeycomb segment laminate.

  Next, the obtained honeycomb segment laminated body 30 is subjected to outer periphery processing as necessary to obtain a desired plugged honeycomb structure 100. Such a manufacturing method is preferable in terms of raw material yield and cost because it does not require a post-process such as cutting. At this time, the inclined segment 1a may be manufactured by forming the plugging portion 25 in the honeycomb segment 1 that has been prepared in advance with an axial length suitable for the inclined segment 1a. The long plugging portion 24 is formed in the honeycomb segment 1 having the same axial length as that of the segment 1, and the end of the long plugging portion forming side has an axial length suitable for the inclined segment 1a. You may produce by cut | disconnecting like this.

  According to the method for manufacturing a plugged honeycomb structure of the present invention, according to the use and purpose, at least a part of the plugged surface has an inclined surface and a notch is formed at a desired position and size. A honeycomb structure can be obtained. When such a plugged honeycomb structure is used as a DPF, in addition to exhibiting an erosion suppressing effect in a limited space in the purification device, it can also be used for a specially shaped container. Exhibits various effects. Furthermore, according to the method for manufacturing a plugged honeycomb structure of the present invention, a decrease in purification performance and strength due to shape processing can be suppressed, and a plugged honeycomb structure excellent in terms of raw material yield and cost can be obtained. Can do. Furthermore, the occurrence of cracks can be prevented by suppressing the uneven distribution of the PM deposition distribution during the DPF regeneration process.

  FIG. 6 is a cross-sectional view schematically showing how exhaust gas flows into one embodiment of the plugged honeycomb structure of the present invention, and FIG. 7 shows another embodiment of the plugged honeycomb structure of the present invention. It is sectional drawing which shows typically a mode that waste gas flows in into. At this time, as shown in FIGS. 6 and 7, since the exhaust gas flows so as to avoid the corner 14 of the notch, in FIG. 6, the cell 5 below the corner 14 of the notch As a result, the exhaust gas is less likely to flow, and therefore, the amount of PM deposited on the partition walls of the cells 5 is reduced, and the amount of PM deposited in the honeycomb segment 1 may become uneven. As a result, when the accumulated PM is burned and the filter is regenerated, the uneven distribution of thermal stress resulting from the difference in the amount of PM deposition may lead to the generation of cracks.

  Therefore, in the plugged honeycomb structure of the present invention, as shown in FIG. 8, the inclined segments 1a are arranged so as to constitute the outer peripheral portion of the plugged honeycomb structure. Inclination from the central part side of the plugged honeycomb structure in which the inclination start point 1a is formed to the outer peripheral part side of the plugged honeycomb structure so that the axial length on the outer peripheral part side of the inclined segment 1a is shortened It is supposed to be an inclined surface. That is, FIG. 8 is a cross-sectional view of the honeycomb structure cut in the axial direction, and the end of the inclined segment on the notch portion side is an inclined surface.

  Of the number of segments constituting the outer peripheral portion of the plugged honeycomb structure, the number of inclined segments is preferably 1 to 3. The number of inclined segments is more preferably 1 to 2. Moreover, when there are two or three inclined segments, it is preferable that the inclined segments are adjacent to each other. For example, as shown in a plugged honeycomb structure 107 in FIG. 14, it is preferable to provide a plurality of inclined segments 1a adjacent to each other. When the number of the inclined segments 1a is plural, the inclined surface 7 is preferably provided so as to have a continuous inclination across the plural inclined segments 1a.

  As shown in FIG. 9, the inclination start point at which the inclined surface starts is formed so as to include at least a part of the joining surface, and the inclination start from the inclination start point to the outer peripheral wall 41 of the honeycomb structure is performed. It is preferable that the ratio H / L of the straight line distance L along the joining surface where the points are formed and the height H of the inclined surface satisfies 0.05 to 1.5.

  In the plugged honeycomb structure of the present invention, the structure of the inclined surface is not particularly limited, and may be an inclined surface having a rectifying effect that can suppress the non-uniformity of PM deposition distribution due to the occurrence of turbulence as described above. It ’s fine. As an example, each embodiment of an inclined surface is shown to FIG. 10A to 10E are cross-sectional views in which the honeycomb structure is cut so as to include an inclined surface in the axial direction.

  FIG. 10A shows that the central side surface of the inclined segment 1a of the plugged honeycomb structure 100 substantially coincides with the end face of the flat segment, and the axial direction 8 of the inclined segment is on the outer peripheral side of the plugged honeycomb structure. The end surface is formed as an inclined surface so that the length is shortened.

  FIG. 10B shows that the length 8 in the axial direction of the inclined segment 1a of the plugged honeycomb structure 101 on the center portion side of the plugged honeycomb structure is shorter than that of the flat segment. The end surface is formed as an inclined surface so that the axial length of the inclined segment becomes shorter toward the outer peripheral side of the body.

  FIG. 10C shows that the length 8 in the axial direction of the inclined segment 1a of the plugged honeycomb structure 102 on the center side of the plugged honeycomb structure is shorter than that of the flat segment, and is parallel to the end surface of the flat segment. The end surface is formed as an inclined surface so that the length of the inclined segment 8 in the axial direction becomes shorter on the outer peripheral side surface toward the outer peripheral side surface.

  FIG. 10D shows that the length 8 in the axial direction of the inclined segment 1a of the plugged honeycomb structure 103 on the center side of the plugged honeycomb structure is shorter than that of the flat segment, and the outer peripheral side thereof extends in the axial direction. 8 An inclined surface is formed so that the length is shortened, and a flat surface parallel to the end surface of the flat segment is formed to the outer peripheral side surface.

  FIG. 10E shows that the length 8 in the axial direction of the inclined segment 1a of the plugged honeycomb structure 104 on the central portion side of the plugged honeycomb structure is shorter than that of the flat segment, and the outer peripheral portion as an inclined surface therefrom. A concave curved surface is formed up to the side surface. The curved surface has a concave curved nose with a maximum curvature, which is located on the center side of the plugged honeycomb structure, and has a streamline shape. Since this curved surface has a streamline shape, it has an excellent rectifying action for preventing turbulent exhaust gas flow.

  FIG. 10F shows that the length 8 in the axial direction of the inclined segment 1a of the plugged honeycomb structure 105 on the center side of the plugged honeycomb structure 105 is shorter than that of the flat segment, and the outer periphery as an inclined surface therefrom. A convex curved surface is formed up to the side surface. The curved surface further has a convex curve nose with the maximum curvature located on the outer peripheral side of the plugged honeycomb structure, and has a streamline shape. Since this curved surface has a streamline shape, it has an excellent rectifying action for preventing turbulent exhaust gas flow.

  The DPF in which the above-described exhaust gas purifying catalyst component is supported on the plugged honeycomb structure of the present invention achieves space saving in the exhaust gas purifying device and has the effect of suppressing erosion, but also the heat during DPF regeneration. It has an end shape that equalizes the stress distribution, and problems such as a decrease in regeneration limit and an increase in pressure loss during DPF regeneration under severe operating conditions are also improved.

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

  As Example 1 to Example 12, plugged honeycomb structures having inclined segments with inclined surfaces as cutout portions were prepared. Further, as Comparative Example 1 and Comparative Example 2, plugged honeycomb structures having no inclined surface and having a short segment with a short axial length as a notch were prepared. These plugged honeycomb structures were each subjected to a pressure loss test and a regeneration limit test using a DPF coated with 30 g / L of catalyst.

  As an overall outer diameter dimension not considering the notch portion of the plugged honeycomb structure used in each example and comparative example, the length in the axial direction of the plugged honeycomb structure: 152 mm, the outermost diameter A cylindrical shape having a diameter of 144 mm was used.

  In Comparative Example 1 and Examples 1 to 6, the position and the number of the honeycomb segments constituting the notch portions are one so as to be the same position as the inclined segment 1a of the plugged honeycomb structure 106 in FIG. did. Further, in Comparative Example 2 and Examples 7 to 12, two segments constituting the cutout portion are positioned at the same position as the two inclined segments 1a adjacent to the outer peripheral portion of the plugged honeycomb structure 107 in FIG. It was. Table 1 shows details of the dimensional conditions of each example and each comparative example.

  Specific dimensions of D, L, and H will be described with reference to cross-sectional views at the joint surface 42 as shown in FIGS. 2A, 2B, and 9. In Table 1, D in Examples indicates the depth from the inflow hole side end face 11 of the plugged honeycomb structure to the inclination start position 40. In the case of the cutout portion 2 having no inclined surface 7 as in Comparative Examples 1 and 2 having the cutout portion 2 without the inclined surface 7 having the shape as shown in FIG. 4, the inflow hole of the cutout portion 2. The depth from the side end face 11 is assumed to be D. In Table 1, L represents a distance from the inclination start position 40 to the outer peripheral wall 41 of the plugged honeycomb structure along the joining surface 42 where the inclination start position 40 is formed. Specifically, of the two side lengths of the side lengths L and L ′ of the inclined segment 1a in the plan view as seen from the end surface 11 on the inlet side of the plugged honeycomb structure 106 as shown in FIGS. , L is the shorter one. In the case of Comparative Examples 1 and 2 having the notched portion 2 having no inclined surface as the short segment 1c, the inclined segment 1a in FIGS. 13 and 14 is replaced with the segment 1c in which the notched portion 2 is formed. Of the side lengths L and L ′ to the outer peripheral wall, the shorter side length is L. As shown in FIG. 9, the height difference H of the inclined surface 7 indicates the inclination start position on the joint surface 42 and the height to the bottom surface of the notch. For Comparative Examples 1 and 2 having no inclined surface, the height difference H is set to 0 mm.

  As the honeycomb segment constituting the plugged honeycomb structure used in each example and comparative example, a square columnar honeycomb segment having a cross section perpendicular to the axial direction and a square having a side length of 36 mm was used. In addition, as the plugged honeycomb structures used in the examples and comparative examples, honeycomb segments having cutout portions are arranged at the corners. A total of 16 flat segments and honeycomb segments (inclined segments, short segments) having cutout portions arranged at the corners are adjacent to each other and laminated through a bonding material layer in which a bonding material is applied to the bonding surface, and pressed. However, the honeycomb segment laminate was obtained by drying at 140 ° C. for 2 hours. Further, this honeycomb segment laminate was cut into a cylindrical shape, coated with a coating material, dried and cured at 700 ° C. for 2 hours to obtain a plugged honeycomb structure. Specifically, it is described below.

  SiC powder and metal Si powder were mixed at a mass ratio of 80:20, and a pore former, an organic binder, a surfactant and water were added thereto to obtain a plastic clay. This kneaded material was extruded and dried to obtain a honeycomb-shaped formed body that was a honeycomb segment. After the honeycomb formed body is dried, the honeycomb formed body is degreased at about 400 ° C. in an air atmosphere, and further fired at about 1450 ° C. in an Ar atmosphere, so that SiC particles in the formed body are made of Si. A honeycomb segment was obtained by bonding.

Next, a base material is applied to the outer wall of the honeycomb-shaped fired body, and is naturally dried. The partition wall thickness is 12 mil (305 μm), the cell shape is square, and the cell density is about 46.5 cells / cm ² (300 cells). / Square inch), a square column-shaped honeycomb segment having a cross-sectional square shape of 36 mm on a side and an axial length of 152 mm was obtained. The base material is a mixture of SiC powder, silica sol aqueous solution and water.

  The inclined segments constituting the notch portions used in Examples 1 to 12 were manufactured by cutting the above-described square columnar honeycomb segments with an end mill in order to obtain a desired inclined surface as described later. As the short segment having the notch used in Comparative Examples 1 and 2, the above-described flat segment was manufactured by the same manufacturing method except that the length in the axial direction was 122 mm by cutting.

  [Preparation of slurry for plugging] Silicon carbide powder and metal silicon powder were mixed at a mass ratio of 75:25, and methyl cellulose, hydroxypropoxyl methyl cellulose, a sintering aid, a pore former and water were added thereto. The mixture was kneaded to obtain a plugging slurry. Strontium carbonate was used as a sintering aid. A foamed resin was used as the pore former.

  [Preparation of Plugged Honeycomb Segment] Masks were alternately formed in a checkered pattern (staggered pattern) in the opening of the cell on one end face of the flat segment, the short segment, and the inclined segment. Specifically, an adhesive film was attached to the entire end face of the honeycomb structure, and only a portion corresponding to a cell in which the plugging portion was to be formed was punched with a laser. And the end surface side which gave the mask was immersed in the slurry for plugging put in the container, and the plugging slurry was filled in the cell of the position corresponding to the hole. At this time, the inclined segment was immersed in the liquid surface in a state where the liquid level of the plugging slurry and the inclined surface were parallel, and filled with the plugging slurry. For the other end face, in the same manner, a mask was formed with a film so that the cells where the plugged portion was not formed on one end face would be in a position corresponding to the opened hole. The side was immersed in a plugging slurry containing silicon carbide, and the plugging slurry was filled into the cells at positions corresponding to the holes. Thereafter, the honeycomb segment filled with the plugging slurry was dried with a hot air dryer.

  [Preparation of bonded honeycomb segment] Next, a slurry for bonding formed by kneading aluminosilicate fiber, colloidal silica, polyvinyl alcohol, and silicon carbide was applied to the peripheral surface of each honeycomb segment, and flat segments and notches were cut. The honeycomb segments having parts were assembled and pressure-bonded to each other, and then dried by heating to obtain a bonded honeycomb segment assembly having an overall shape of a quadrangular prism.

  Then, after the honeycomb segment bonded body is ground into a cylindrical shape, the peripheral surface thereof is covered with an outer peripheral coat layer made of the same material as the honeycomb segment molded body, and is cured by drying, so that the cylindrical shape having a segment structure is formed. A plugged honeycomb structure was obtained.

(Evaluation)
Pressure loss measurement test:
Exhaust gas was generated using a diesel engine (TDI) with a direct injection turbo with a displacement of 2000 cc, and a pressure loss test was performed. A DPF having a plugged honeycomb structure coated with 30 g / L of catalyst as shown in each comparative example and example in Table 1 was used. A soot deposition amount of 8 g / L was deposited on each DPF. The engine rotation speed is 3000 rpm, the engine torque is 50 Nm, the gas flow rate is 3.5 to 4.5 m ³ / min, and the soot is deposited on the DPF under the exhaust gas temperature of 250 to 350 ° C. In relation, the pressure loss of the DPF before and after the exhaust gas flow direction was measured. Pressure loss is the pressure loss of Examples 1 to 6 when each pressure loss value (kPa) at the time of depositing soot to 8 g / L is used and the pressure loss value (kPa) of Comparative Example 1 is used as a reference. Table 1 shows the results of the pressure loss change rate [%] of Examples 7 to 12 when the change rate [%] and the pressure loss value (kPa) of Comparative Example 2 are used as a reference.

Regeneration limit test:
The test is performed with the notch part in the downward direction by changing the conditions such as the presence or absence of the inclined surface of the notch part and the position and size of the inclined surface. A DPF having a plugged honeycomb structure coated with 30 g / L of catalyst as shown in each comparative example and example in Table 1 was used. The amount of soot (PM) deposited was increased successively to regenerate the filter (PM combustion), and the limit of cracking was confirmed (PM amount step-up regeneration test). A diesel engine with a direct-injection turbo (TDI) with a displacement of 2000 cc was used, soot was deposited on the DPF while maintaining the engine speed at 2000 rpm and the engine torque at 60 Nm. Next, the gas temperature at the inlet of the DPF was raised to 650 ° C. by post-injection, and when the pressure loss before and after the DPF began to drop, the engine operating condition was set to the idle state, and at the same time, the post-injection was stopped. Thereafter, the internal temperature of the DPF increased rapidly due to the high oxygen concentration and the low exhaust flow rate. The amount of soot deposited on the DPF was varied, and the amount of soot that generated cracks on the DPF outlet end face was compared. Regarding the presence or absence of cracks, the presence or absence of ring-off cracks divided in the cross-sectional direction perpendicular to the axial direction of the DPF was observed using a CT scan. The soot amount when a crack occurred on the end face of the DPF was defined as the regeneration limit value of the DPF. The difference (g / L) from the reference value of Examples 1-6 when the soot accumulation amount (g / L) at the time of crack occurrence in Comparative Example 1 is used as the reference value, and the soot at the time of crack occurrence in Comparative Example 2 The results of the difference (g / L) from the reference values of Examples 7 to 12 when the deposition amount (g / L) is used as the reference value are shown in Table 1.

  As Comparative Examples 1 and 2, a regeneration limit test was performed using a plugged honeycomb structure 151 having a short segment 1c having no inclined surface as shown in FIG. Specifically, those having dimensions as shown in Table 1 were used. In Comparative Example 1 and Examples 1-6, L was 20 mm, in Comparative Example 2 and Examples 7-12, L was 36 mm, and other conditions were changed, and the above-described pressure loss test and regeneration limit test were performed.

  As a result of the pressure loss test and the regeneration limit test, in the case of using the plugged honeycomb structure provided with the notched portion having the inclined surface of Examples 1 to 12, a flat notched portion without the inclined surface is used. Compared with Comparative Example 1 and Comparative Example 2 using the plugged honeycomb structure, the pressure loss was reduced and the regeneration limit was improved.

  Further, in Example 6, as shown in FIG. 1, the start position 40 of the inclined surface 7 is on the end face 11 of the inflow hole of the plugged honeycomb structure 100, and the loss coefficient at this time is minimized, and the regeneration limit test is performed. The amount of soot accumulation at the site was also the largest.

  Thus, as shown in each Example, it is preferable that H / L is 0.05-1.5 as a ratio with the height H of the inclined surface. By setting such a value, while maintaining both the erosion suppressing effect and the size reduction due to the provision of the notch part, the occurrence of turbulent flow at the notch part is prevented, the regeneration limit is lowered during the regeneration of the DPF, the pressure It was shown that problems such as increased loss were also improved.

  The plugged honeycomb structure of the present invention and the DPF using the same equalize the distribution of thermal stress during regeneration of the DPF while achieving space saving and suppressing erosion in the exhaust gas purification device. Since it has an end shape and problems such as a decrease in regeneration limit during DPF regeneration under severe operating conditions and an increase in pressure loss are improved, industrial applicability increases.

1: honeycomb segment, 1a: inclined segment, 1b: flat segment, 1c: short segment, 2: notch, 3: bonding material layer, 4: flat surface, 5: cell, 6: partition wall, 7: inclined surface, 8: Axial direction, 9: Honeycomb catalyst body, 11: Inlet hole side end face, 12: Outlet hole side end face, 13: Foreign substance collecting pocket, 14: Corner part of notch, 15: Container, 18: DPF, 24 : Long-sealed portion, 25: plugged portion, 26: end mill, 27: long-sealed portion. 30: Honeycomb segment laminated body, 40: Inclination start position, 41: Outer peripheral wall, 42: Bonding surface, 50: Crack, 51: Region, 52: Region, 100, 101, 102, 103, 104, 105, 106, 107 : Plugged honeycomb structure, 110, 120, 130: exhaust gas purification device.

Claims (3)

A plurality of cells serving as fluid flow paths partitioned by porous partition walls, the adjacent cells being composed of a plurality of honeycomb segments plugged at one end opposite to each other; A plugged honeycomb structure for a diesel particulate filter in which the honeycomb segments are adjacent to each other, and are integrally bonded via a bonding material layer at the bonding surfaces of the plurality of adjacent honeycomb segments,
At least a part of the honeycomb segment arranged on the outer peripheral side of the plugged honeycomb structure has an end face on the fluid inflow hole side toward the outer peripheral side from the center side of the plugged honeycomb structure. An inclined segment having at least a part of an inclined surface inclined so as to reduce the axial length of the sealed honeycomb structure ,
The inclined surface is a plugged honeycomb structure provided in a part of an outer peripheral portion of the plugged honeycomb structure. An inclination start position where the inclined surface starts is formed on the joint surface,
The ratio H / L of the distance L from the inclination start position to the outer peripheral wall of the honeycomb structure along the joining surface where the inclination start position is formed and the height H of the inclined surface is 0.05 to 1. The plugged honeycomb structure according to claim 1, which is in a range of .5.   A diesel particulate filter in which the plugged honeycomb structure according to claim 1 or 2 is loaded with a catalyst component for exhaust gas purification.

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