JP4413877B2 - Exhaust gas purification catalytic converter - Google Patents

Description

  The present invention relates to an exhaust gas purifying catalytic converter, and more particularly to an assembly structure of a holding seal body.

  Conventionally, as shown in FIG. 4 to be described later, an exhaust gas purifying catalytic converter mainly mounted on a vehicle includes a catalyst carrier 1, a metal shell 95 covering the outside thereof, and an inorganic fiber mat-like material disposed between the two. The holding seal body 2 is made of.

The catalyst carrier 1 carries a catalyst component such as platinum. As the catalyst carrier 1, for example, there is a honeycomb body made of cordierite. The exhaust gas purification catalytic converter 90 is disposed in the middle of an exhaust pipe 99 connected to the engine E.
The shell 95 has the catalyst carrier 1 and the holding seal body 2 disposed therein, and then the inlet-side connecting portion 97 and the outlet-side connecting portion 98 are coupled to the front and rear openings.

  Next, the holding seal body 2 made of the inorganic fiber mat-like material prevents the exhaust gas from leaking between the catalyst carrier 1 and the shell 95, and the catalyst carrier 1 is a shell when the automobile is running. Used to prevent contact with 95 and damage.

As a means for disposing the holding seal body 2 between the catalyst carrier 1 and the shell 95, for example, the shell 95 is divided into two semicircular parts, and the holding seal body is placed on the outer periphery of the catalyst carrier 1 therein. There is a method in which an integral product wound with 2 is put, and then the two shells 95 are joined in a cylindrical shape.
Alternatively, there is a method in which the shell 95 has a C shape and a U shape in cross section, the above-mentioned integrated product is put therein, and then the shell 95 is closed into a cylindrical shape.
In recent years, for example, JP-A-7-197813 discloses an attachment method in which a plate-like ceramic fiber is inserted into an airtight sheet for the purpose of preventing damage and deterioration of the holding seal body. In order to improve workability and simplify the process, as shown in FIG. 2 described later, a cylindrical shell 95 is prepared from the beginning, and a press-fit assembly method in which the integrated product 20 is press-fitted therein is adopted. ing.

  By the way, conventionally, as a method for winding and holding the holding seal body 2 around the catalyst carrier 1, as shown in FIG. In addition, a recess 87 is formed at one end of the recess, and a protrusion 88 having a size that fits into the recess 87 is formed at the other end by cutting.

That is, the concave portion 87 is formed by cutting one end of the inorganic fiber mat-like material 89, and the projecting portion 88 is disposed around the other end of the inorganic fiber mat-like material 89 so that the projecting portion 88 remains. It is formed by excising.
The holding seal body 2 processed in this way is wound around the outer periphery of the catalyst carrier 1 as shown in FIG. 7B, and the protruding portion 88 is inserted into the recess 87. The holding seal body 2 is fixed to the outer periphery of the catalyst carrier 1 with a tape and an adhesive and assembled in the shell 95.

  In the exhaust gas purifying catalytic converter 90, a gap is formed at the mating portion of the inorganic fiber mat-like material 89, exhaust gas enters this portion, and the surface temperature of the outer wall of the catalyst carrier 1 varies depending on whether the mat is present or not. There will be a difference. This temperature difference may cause cracking of the catalyst carrier 1. In order to prevent this, it is effective to eliminate the gap.

On the other hand, conventionally, after a catalyst component such as a noble metal is supported on a catalyst carrier, it is mounted on a shell to form an exhaust gas purifying catalytic converter. However, in recent years, there has been a movement to reduce the thickness of the catalyst carrier wall in order to improve the exhaust gas purification performance, and in order to prevent damage to the catalyst carrier, it has been studied to handle it in a state where it is assembled in the shell via a holding seal body. ing.
In addition, in order to comply with exhaust gas regulations, studies have been made to burn off organic components in the holding seal body in advance.
In order to cope with these, a method in which an unsupported carrier on which a catalyst component is not yet supported is assembled in a shell via a holding seal body, and then a catalyst solution is attached to the inner wall of the unsupported carrier, heated and fired, and supported. Is being considered. According to this method, the organic component in the holding sealing body can be simultaneously burned off during heating and baking.

Next, details of a method of attaching the catalyst solution to the inner wall of the unsupported carrier after the unsupported carrier is assembled in the shell via the holding seal body will be described.
The unsupported carrier 11 having the holding seal body 2 wound around the outer periphery is assembled in the shell 95, and then supports the catalyst component on the unsupported carrier 11 as shown in FIG.
That is, the pipes 71 and 72 are pressed against the lower and upper sides of the integrated product after assembling, and the slurry-like catalyst solution 70 is supplied into the unsupported carrier 11 in the axial direction from above and below. As a result, the catalyst solution 70 adheres to the honeycomb wall of the unsupported carrier 11.

Thereafter, the pipes 71 and 72 are removed, and the assembly of the catalyst carrier 1, the holding seal body 2, and the shell 95 is heated to high temperature and fired. Thereby, the catalyst solution 70 attached to the catalyst carrier 1 becomes a catalyst component and is supported on the catalyst carrier 1. Thereby, the exhaust gas purifying catalytic converter 90 is completed.
After that, as shown in FIG. 4 to be described later, it is arranged in the middle of the exhaust pipe 99.

However, the conventional exhaust gas purifying catalytic converter 90 has the following problems.
That is, as shown in FIG. 9, since the catalyst carrier 1 and the holding seal body 2 have a dimensional tolerance, when they are wound, a gap C is formed between the end portions 881 and 871. Therefore, when the catalyst solution 70 is supplied to the unsupported carrier 11 (see FIG. 8), the catalyst solution 70 leaks out from the mating gap C. Since the catalyst metal is a noble metal, there has been a problem that leakage or adhesion to other than the catalyst carrier 1 leads to an increase in cost as a product.

  In view of the conventional problems, the present invention provides an exhaust gas purifying catalyst capable of supporting a catalyst component on the catalyst carrier without causing the catalyst solution to leak from the gap between the holding seal bodies when the catalyst solution is supplied to the catalyst carrier. An object of the present invention is to provide a converter and a holding seal body used therefor.

Next, the invention of claim 1 is directed to an exhaust gas purifying catalytic converter having a catalyst carrier and a shell covering the outside of the catalyst carrier, the inorganic fiber mat being disposed between the shell and the catalyst carrier. A holding seal body formed by winding a material around the outer periphery of the catalyst carrier,
When performing the winding arrangement, at least one end of the inorganic fiber mat is an oblique end formed obliquely with respect to the thickness direction,
The holding seal body is characterized in that when the oblique end portion is overlapped with the other end portion, it is longer than the outer peripheral length of the catalyst carrier, and a convex portion is formed by overlapping .

  The most notable point in the present invention is that at least one end of the inorganic fiber mat-like material is an oblique end formed obliquely with respect to the thickness direction, and the oblique end is used as the other end. The holding seal body is formed so as to overlap the portion.

  In the present invention, at the time of performing the winding arrangement, at least one end portion of the inorganic fiber mat-like material is cut obliquely with respect to the thickness direction to form an oblique end portion. Then, the inorganic fiber mat-like material is wound around the catalyst carrier so that the oblique end portion is positioned on the outer periphery of the other end portion and the inclined surface is superimposed on the other end portion, A holding seal body is formed. That is, the inclined end portion is intentionally overlapped with the other end portion so that the above-mentioned gap is not formed.

By the way, a convex part may be formed on the surface of the holding sealing body due to the above-described overlap. However, this convex portion can be squeezed by the shell when it is assembled inside the shell, and can be stored inside the shell.
That is, the thickness of the inclined end portion is smaller than the thickness of the inorganic fiber mat-like material. Therefore, even if it overlaps intentionally, a holding seal body can be stored in the inside of a shell and an alignment gap can be eliminated. Therefore, according to the present invention, the catalyst converter for exhaust gas purification that can carry the catalyst component on the catalyst carrier without the leakage of the catalyst solution from the gap between the holding seal bodies when the catalyst solution is supplied to the catalyst carrier can be retained. A seal body can be provided.

Next, the invention of claim 2 is directed to a catalyst carrier, a shell covering the outside of the catalyst carrier, and between the shell and the catalyst carrier, and an inorganic fiber mat is placed on the outer periphery of the catalyst carrier. In an exhaust gas purifying catalytic converter having a holding seal body formed by winding,
When the winding arrangement is performed, at least one end of the inorganic fiber mat-like material is an oblique end formed obliquely with respect to the thickness direction, and the oblique end is connected to the other end. The exhaust gas purifying catalytic converter is characterized in that a holding seal body, which is longer than the outer peripheral length of the catalyst carrier when overlapped with the end portion and has a convex portion formed by overlapping, is press-fitted .

Also according to the present invention, as described in the description of the invention of claim 1 , the catalyst solution is not leaked from the gap between the holding seal bodies when the catalyst solution is supplied to the catalyst carrier, and the catalyst component is supported on the catalyst carrier. It is possible to provide an exhaust gas purifying catalytic converter capable of

  Moreover, in the above, as the inorganic fiber mat-like material, it is preferable to use inorganic fibers such as crystalline alumina fibers, alumina-silica fibers or silica fibers, or those containing one or more kinds of these inorganic fibers. In this case, a holding seal body excellent in durability can be formed.

Embodiment 1
An embodiment of the present invention will be described with reference to FIGS.
As shown in FIG. 3, the exhaust gas purifying catalytic converter 10 in this example is disposed between the catalyst carrier 1, a shell 95 that covers the outside of the catalyst carrier 1, and the shell 95 and the catalyst carrier 1. A holding seal body 2 formed by winding an inorganic fiber mat-like material 200 around the outer periphery of the catalyst carrier 1;

  As shown in FIGS. 1A to 1D, when performing the winding arrangement, an inorganic fiber mat-like material 200 longer than the outer peripheral length of the catalyst carrier 1 is wound around the catalyst carrier 1. Then, after cutting one end portion 21 of the inorganic fiber mat-like product 200, the one end portion 21 and the other end portion 22 of the inorganic fiber mat-like product 200 are arranged to face each other to form the holding seal body 2. To do.

This will be described in detail below.
First, the shapes, dimensions, materials, and the like of main components used when manufacturing the exhaust gas purifying catalytic converter 10 will be described.
As the catalyst carrier 1, a honeycomb cordierite monolith having an outer diameter of 130 mm and a length of 100 mm was used. The catalyst carrier 1 is provided with a number of square holes 111 along the axial direction thereof. A large number of honeycomb walls 112 serving as partition walls are formed between the square holes 111, and the wall thickness of the honeycomb walls 112 is 50 μm (see FIG. 2).

The shell 95 is a SUS409 metal cylinder formed in a cylindrical shape. The shell 95 has an outer diameter of 141 mm and a plate thickness of 1.5 mm.
As the inorganic fiber mat-like material 200, crystalline alumina fibers having a thickness of 8 mm and a bulk density of 0.2 g / cm 3 were used. In addition, the inorganic fiber mat-like product 200 before the cutting has a length L. This length L is longer than the outer peripheral length R of the catalyst carrier 1.
Further, as the catalyst solution 70, a solution containing platinum and palladium was used.

Next, a method for manufacturing the exhaust gas purifying catalytic converter 10 will be described.
First, as shown in FIG. 1A, the inorganic fiber mat 200 having a length longer than the outer circumference of the catalyst carrier 1 is prepared. And the shape is provided in both these edge parts 21 and 22 so that the one edge part 21 of the inorganic fiber mat-like thing 200 may fit in the other edge part 22. FIG. That is, one end 21 is cut so that the middle portion in the width direction of the inorganic fiber mat-like product 200 is convex, and the convex 211 is formed. In addition, the other end portion 22 is cut so that the middle portion in the width direction of the inorganic fiber mat-like material 200 becomes a concave shape, and a concave portion 221 having a shape that fits the convex portion 211 is formed.

  Next, as shown in FIGS. 1B and 1C, a catalyst carrier 1 that does not yet carry a catalyst component is placed on the inorganic fiber mat 200, and the catalyst carrier 1 is inorganic. The fiber mat 200 is wound once. At this time, the end 21 overlaps the end 22 of the inorganic fiber mat-like material 200. That is, at this time, an excess portion 23 is formed in the longitudinal direction of the inorganic fiber mat-like product 200 due to this overlap. Then, the surplus portion 23 is cut along a dotted line 29.

  Next, as shown in FIG. 1D, the cut-out convex portion 211 is fitted into the concave portion 221, that is, the end surface of one end portion 21 and the end surface of the other end portion 22 are opposed to each other. The fiber mat 200 is placed on the outer periphery of the catalyst carrier 1. In this way, the holding seal body 2 is formed.

  Next, the holding seal body 2 is fixed to the catalyst carrier 1 with a fixing tool such as a tape or an adhesive, so that an integrated product 20 is obtained. At this time, the alignment gap C formed between one end 21 and the other end 22 was 0 to 0.5 mm (see FIG. 3).

Next, as shown in FIG. 2, the unitary product 20 is press-fitted into the shell 95.
Then, in the same manner as shown in FIG. 8 described above, preparations for supporting the catalyst component on the catalyst carrier 1 are made. That is, the press-fitted shell 95 is vertically arranged, and the pipe 71 is pressed against the lower end surface of the catalyst carrier 1 inside the integrated product 20 and the pipe 72 is pressed against the upper end surface of the catalyst carrier 1. Then, a slurry-like catalyst solution 70 is supplied from above the pipe 72 into the catalyst carrier 1 along its axial direction. Thus, the catalyst solution 70 is permeated into the catalyst carrier 1.

Next, the catalyst carrier 1 is dried, and then a baking step is performed, so that the catalyst components are supported on the numerous honeycomb walls 112 in the catalyst carrier 1. In this baking process, the organic component contained in the holding seal body 2 can be burned out.
As shown in FIG. 3, the exhaust gas purifying catalytic converter 10 is thus completed.
And after removing the pipes 71 and 72, as shown in FIG. 4, the inlet side connection part 97 and the outlet side connection part 98 are respectively connected to each end of the shell 95, and welding is performed on this connection part. Integrate. The exhaust gas purification catalytic converter 10 is disposed in the middle of the exhaust pipe 99 of the automobile engine E.

Of course, the surplus portion 23 formed when the inorganic fiber mat-like material 200 is wound around the catalyst carrier 1 may be formed only on the convex portion 211 or only on the end portions 212 on both sides of the convex portion 211 ( (See FIGS. 1A and 1B).
In this example, the end portion 21 side having the convex portion 211 is used as the surplus portion 23, but the end portion 22 side having the concave portion 221 may be used as the surplus portion 23.
When supplying the catalyst solution 70 to the catalyst carrier 1, only the pipe 71 is used and pressed against the lower end surface of the catalyst carrier 1, and the slurry-like catalyst solution 70 is placed in the catalyst carrier 1 from below the pipe 71. May be supplied along the axial direction.

Next, the function and effect of this example will be described.
In this example, after the inorganic fiber mat-like product 200 is aligned with the actual catalyst carrier 1 having a dimensional error, the surplus portion 23 in the inorganic fiber mat-like product 200 is cut. Therefore, the inorganic fiber mat-like product 200 can be cut into any length that is actually required for the holding seal body 2. Therefore, the fitting gap C formed between the one end 21 and the other end 22 of the holding seal body 2 can be almost eliminated.

Therefore, when the catalyst solution 70 is supported on the catalyst carrier 1, the catalyst solution 70 does not leak out from the fitting gap C to the shell 95 side. Therefore, the noble metal contained as a catalyst component in the catalyst solution 70 can be supported on the catalyst carrier 1 without being wasted.
For this reason, the catalyst solution 70 does not leak and adhere to the shell 95. Therefore, there is no inconvenience when welding the inlet side connecting portion 97 or the outlet side connecting portion 98 to each end of the shell 95.

Here, the allowable width as the alignment gap C is considered as follows.
That is, the inorganic fiber mat-like product 200 is fixed to the catalyst carrier 1 with a fixing tool such as a tape or an adhesive after the excess portion 23 is cut, so that an integrated product 20 is obtained. Next, the integrated product 20 is press-fitted into the shell 95. Then, as described above, the catalyst solution 70 is supplied to the catalyst carrier 1, and the width within the range in which the catalyst solution 70 does not leak to the shell 95 side is considered as the width allowed for the alignment gap C. And it was found that if the width of the alignment gap C is 1 mm or less, leakage can be reliably prevented.

  The inorganic fiber mat-like product 200 may be cut by cutting the surplus portion 23 while aligning the inorganic fiber mat-like product 200 with the catalyst carrier 1. Further, when the inorganic fiber mat-like material 200 is combined with the catalyst carrier 1, the length of the surplus portion 23 may be measured, and cutting may be performed by the length.

Embodiment 2
In this example, as shown in FIG. 5, when the alignment gap C exceeds 1 mm, the alignment gap C is filled with the filling sheet 3 made of the same material as the inorganic fiber mat-like material 200 and the holding seal is used. The body 2 is formed.
Further, when performing the winding arrangement, an inorganic fiber mat-like material 200 shorter than the outer peripheral length of the catalyst carrier 1 is wound around the catalyst carrier 1. Specifically, the alignment gap C was 5 mm. Others are the same as in the first embodiment.

In this example, the filling gap 3 which is a member different from the inorganic fiber mat-like material 200 is filled in the fitting gap C, and the width of the fitting gap C is set to 1 mm or less. Therefore, the alignment gap C can be almost eliminated. Therefore, also in this example, when the catalyst solution 70 is supplied to the catalyst carrier 1, the catalyst solution 70 does not leak from the fitting gap C of the holding seal body 2.
In addition, the same effects as those of the first embodiment can be obtained.

Embodiment 3
In this example, as shown in FIGS. 6 (A) to 6 (C), when the winding arrangement is performed, both ends of the inorganic fiber mat-like product 200 are inclined with respect to the thickness direction. The formed oblique ends 24 and 25 are formed.
That is, as shown in FIG. 6A, one oblique end portion 24 and the other oblique end portion 25 are substantially in the thickness direction in a state where the inorganic fiber mat-like material 200 is spread in a planar shape. It is formed in a parallel oblique shape. One oblique end 24 has a convex portion 241, and the other oblique end 25 has a concave portion 251.

  Then, as shown in FIGS. 6B and 6C, when the winding arrangement is performed, the slanted end 24 is positioned on the outer periphery of the slanted end 25 and is slanted. The inclined surface 242 at the end portion 24 is disposed so as to overlap the inclined surface 252 at the inclined end portion 25. In this manner, the inorganic fiber mat 200 is wound around the catalyst carrier 1 to form the holding seal body 2. Others are the same as in the first embodiment.

  In this example, one inclined end portion 24 is intentionally overlapped with the other inclined end portion 25 so that the above-mentioned alignment gap C is not formed. At this time, when the outer peripheral length of the inorganic fiber mat-like product 200 after being wound is slightly longer than the actual outer peripheral length of the catalyst carrier 1, it protrudes from the surface of the holding seal body 2 due to the overlap. A shaped part 260 is formed. However, the convex portion 260 can be squeezed by the shell 95 and fit into the shell 95 when press-fitting into the shell 95.

That is, the thickness of the convex portion 260 is thinner than the thickness of the inorganic fiber mat-like material 200. Therefore, even if the overlap is intentionally made, the holding seal body 2 can be accommodated in the shell 95 and the above-mentioned alignment gap C can be eliminated. Therefore, also in this example, when the catalyst solution 70 is supplied to the catalyst carrier 1, the catalyst solution 70 does not leak from the fitting gap C of the holding seal body 2.
In addition, the same effects as those of the first embodiment can be obtained.

  In this example, the slanted end portions 24 and 25 are formed in advance before the winding arrangement. However, either one or both of the oblique end portions 24 and 25 are formed in the inorganic fiber mat-like material when the inorganic fiber mat-like material 200 is wound around the catalyst carrier 1 as described in the first embodiment. 200 may be cut and formed.

Obviously, the oblique ends 24 and 25 may be formed in an oblique shape opposite to the present example with respect to the thickness direction. At this time, the inclined end 25 is positioned on the outer periphery of the inclined end 24, and the inclined surface 252 at the inclined end 25 overlaps the inclined surface 242 at the inclined end 24. Is done.
Further, either one of the oblique end portions 24 and 25 may be formed in a right-angle shape as in the first embodiment.

  As described above, according to the present invention, there is no leakage of the catalyst solution from the gap between the holding seal bodies when the catalyst solution is supplied to the catalyst carrier, and the exhaust gas purifying catalytic converter that can carry the catalyst component on the catalyst carrier. Can be provided.

In the example of Embodiment 1, it is a figure which shows the method of forming a holding | maintenance sealing body, (A) Perspective view which shows the inorganic fiber mat-like thing before winding arrangement | positioning, (B) Winding an inorganic fiber mat-like thing around a catalyst support | carrier The perspective view which shows a state, (C) The explanatory view which shows the state which cut | disconnects the excess part made to the inorganic fiber mat-like thing, (D) The perspective view which shows the state which formed the holding seal body. The perspective view which shows the state which press-fits the integral goods which fixed the holding seal body to the catalyst carrier in Embodiment 1 to a shell. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing an exhaust gas purifying catalytic converter in Embodiment 1; Explanatory drawing which shows the state which has arrange | positioned the exhaust gas purification catalytic converter in the middle of the exhaust pipe of the engine in Embodiment 1. FIG. Explanatory drawing which shows the catalytic converter for exhaust gas purification in Embodiment Example 2. FIG. FIG. 5 is a view showing a method for forming a holding seal body in Embodiment 3; (A) a perspective view showing an inorganic fiber mat-like material before winding arrangement; (B) winding the inorganic fiber mat-like material around a catalyst carrier; The perspective view which shows the state which showed, (C) The perspective view which shows the state which formed the holding | maintenance seal body. It is a figure which shows the method of forming a holding | maintenance sealing body in a prior art example, (A) The perspective view which shows the inorganic fiber mat-like thing before winding arrangement | positioning, (B) The perspective view which shows the state which formed the holding sealing body. Explanatory drawing which shows the method to supply a catalyst solution to the catalytic converter for exhaust gas purification | cleaning in a prior art example. Explanatory drawing which shows the catalytic converter for exhaust gas purification | cleaning in a prior art example.

Explanation of symbols

1. . . Catalyst support,
10. . . Exhaust gas catalytic converter,
2. . . Holding seal body,
21,22. . . edge,
23. . . Surplus part,
200. . . Inorganic fiber mat,
95. . . shell,

Claims (2)

In an exhaust gas purifying catalytic converter having a catalyst carrier and a shell covering the outside of the catalyst carrier, the inorganic fiber mat is disposed between the shell and the catalyst carrier and wound around the outer periphery of the catalyst carrier. A holding seal body formed by being arranged in a turn,
When performing the winding arrangement, at least one end of the inorganic fiber mat is an oblique end formed obliquely with respect to the thickness direction,
A holding seal body characterized in that when the oblique end portion is overlapped with the other end portion, it is longer than the outer peripheral length of the catalyst carrier, and a convex portion is formed by overlapping . A catalyst carrier, a shell that covers the outside of the catalyst carrier, and a holding member that is disposed between the shell and the catalyst carrier and is formed by winding an inorganic fiber mat around the periphery of the catalyst carrier. In an exhaust gas purifying catalytic converter having a seal body,
When the winding arrangement is performed, at least one end of the inorganic fiber mat-like material is an oblique end formed obliquely with respect to the thickness direction, and the oblique end is connected to the other end. A catalytic converter for purifying exhaust gas, wherein a holding seal body, which is longer than the outer peripheral length of the catalyst carrier when overlapped with an end portion and has a convex portion formed by overlapping, is press-fitted .

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