JP4465783B2 - Exhaust gas purification catalytic converter and method of manufacturing the same - Google Patents

Description

[0001]
【Technical field】
The present invention relates to an exhaust gas purification catalytic converter used for an internal combustion engine such as an automobile and a method for manufacturing the same, and more particularly to a method for assembling a holding seal material.
[0002]
[Prior art]
An exhaust gas purifying catalytic converter mounted on a vehicle includes a catalyst holding body carrying a catalyst for purifying exhaust gas, a metal shell covering the outside of the catalyst holding body, and a holding sealing material disposed therebetween. .
The holding sealing material is mainly composed of a mixture of vermiculite and ceramic fibers. However, in recent years, the holding seal material consists only of inorganic fibers with excellent heat resistance in consideration of environmental impact and exhaust gas temperature rise. Sealing materials are also used.
The holding sealing material prevents the catalyst holding body from being damaged when the catalyst holding body comes into contact with the outer metal shell while the vehicle is running. Further, the exhaust gas is prevented from leaking from between the metal shell and the catalyst carrier.
Here, since the holding sealing material made of inorganic fibers is extremely bulky in the initial state, the assemblability is significantly lowered.
[0003]
In view of this, the inventors have proposed to improve the assembling property of the catalyst holding body to the metal shell by vacuum-packing the holding sealing material using an organic film and reducing the thickness (Japanese Patent Laid-Open No. 57-146554). No. 59, No. 59-126033). In addition, a method has also been proposed in which a holding sealing material is wound around a catalyst holding body and vacuum packed together with the catalyst holding body (Japanese Patent Laid-Open No. 50-63549).
[0004]
In order to improve workability, it is conceivable to use a metal pipe as the metal shell and insert a holding seal material wound around the catalyst holder. In this case, when inserting the holding sealing material into the metal pipe, a method of reducing the thickness by vacuum-packing the holding sealing material with an organic film in advance, or a method of adding an organic binder to the holding sealing material and molding to a predetermined thickness in advance. Can be taken.
[0005]
[Problems to be solved]
However, the organic film and the organic binder generate combustion gas, so there is concern about the impact on the environment. Therefore, it is necessary to make the organic amount as close to “0” as possible.
However, in this case, a problem arises in the airtightness of the organic film, and it becomes difficult to adjust the thickness of the holding sealing material. For this reason, the assembly | attachment property to the metal shell of a holding sealing material will worsen.
[0006]
In view of the conventional problems, the present invention is intended to provide an exhaust gas purifying catalytic converter excellent in assembling property of a catalyst holder to a metal pipe and considering the influence on the environment, and a method for manufacturing the same.
[0007]
[Means for solving problems]
The invention according to claim 1 is a catalyst holding body in which a catalyst for purifying exhaust gas is supported on a carrier, a metal pipe covering the outside of the catalyst supporting body, and between the catalyst supporting body and the metal pipe. In a manufacturing method of a catalytic converter for purifying exhaust gas comprising a holding sealing material interposed in
Cutting one end face in the width direction of the holding sealing material made of an inorganic fiber mat so as to have an angle, and winding the holding sealing material around the outer periphery of the catalyst holding body to obtain a wound body;
Arranging two metal pipes having one end portion expanded in a funnel shape on both sides of the wound body with the expanded side of the metal pipe facing the wound body;
Press-fitting the wound body into the metal pipe;
A method of manufacturing a catalytic converter for purifying exhaust gas, comprising the step of fixing the expanded sides of the metal pipe.
[0008]
In the present invention, after a holding sealing material is wound around the catalyst holder to obtain a wound body, two metal pipes are arranged on both sides of the wound body, and the wound body is press-fitted into the metal pipe. ing. Therefore, it is possible to press-fit with less force than when the wound body is press-fitted into one metal pipe.
The metal pipe is press-fitted into the wound body from the expanded opening side. Therefore, the wound body can be press-fit smoothly.
Therefore, according to this manufacturing method, the catalyst holder can be easily assembled to the metal pipe.
[0009]
Further, although the holding sealing material made of the inorganic fiber mat is bulky, it can be easily press-fitted into the metal pipe as described above. Therefore, it is not necessary to use an organic binder or an organic film for reducing the thickness. Therefore, combustion gas of the organic binder is not generated from the holding sealing material, and the influence on the environment is reduced.
[0010]
The metal pipe 2 may be expanded with a gradient on the entire side surface (FIG. 4), or may be expanded from the middle of the side surface (FIG. 5). The expanded portion may be a linear gradient or a curved gradient.
[0011]
The inner diameter of the expanded side of the metal pipe may be equal to or larger than the diameter of the wound body, and the inner diameter of the metal pipe opposite to the expanded side may be smaller than the diameter of the wound body. preferable. Thereby, it becomes easy to press-fit the wound body into the metal pipe.
[0012]
As in the invention of claim 2, it is preferable that the filling density of the holding sealing material before the metal pipe is press-fitted is 0.1 to 0.2 g / cm ³ . When it exceeds 0.2 g / cm ³ , the force of holding the catalyst holder of the holding sealing material may be reduced. If it is less than 0.1 g / cm ³ , the wrapping property around the catalyst holder may be lowered.
[0013]
The holding sealing material is preferably not impregnated with a binder. Thereby, the organic component is not discharged as exhaust gas from the holding sealing material, and the amount of exhaust gas can be reduced.
[0014]
The inorganic fiber mat constituting the holding sealing material can be produced from inorganic fibers such as alumina, silica, and alumina-silica. In addition, glass fiber metal can be used depending on the operating temperature range. Since the inorganic fiber mat is in an extremely bulky state in the initial state, the one subjected to needle punching from the viewpoint of workability is preferable.
[0015]
As in the invention of claim 3, the inorganic fiber mat constituting the holding sealing material is preferably made of crystalline alumina fibers. Thereby, the heat resistance of the holding sealing material is improved.
[0016]
The catalyst supported on the catalyst holder may be any catalyst that can purify the exhaust gas. For example, platinum, panadium, rhodium, or the like can be used. The carrier carrying the catalyst can be made of cordierite, alumina, metal or the like.
The metal pipe is, for example, a cylinder having an oval cross section and is made of a heat resistant material such as SUS409.
[0017]
According to a fourth aspect of the present invention, the holding sealing material is composed of two members, and the gap between the members when the two members are wound around the catalyst holding body is preferably 3 mm or more. Thereby, the shearing force between the metal pipe and the holding sealing material generated during press-fitting can be released, and deterioration of the holding sealing material due to heat can be prevented when welding the butt portion of the metal pipe. When the gap between the members of the holding sealing material is less than 3 mm, there is a possibility that the holding sealing material interferes and is difficult to press-fit.
Methods for fixing metal pipes include caulking and welding.
[0018]
The invention of claim 5 is an exhaust gas purifying catalytic converter manufactured by the method of any one of claims 1 to 4.
[0019]
Since the exhaust gas purification catalytic converter has the above-described configuration, it can be easily manufactured.
Moreover, the narrow part which is not expanded in the metal pipe compresses the holding sealing material to increase the filling density of the holding sealing material. Therefore, the holding sealing material has a high holding force in a narrow portion, and the catalyst holding body can be held securely.
[0020]
As in the present invention 6, the packing density of the holding sealing material in the metal shell, when it is 0.20~0.60g / cm ³ is less than preferred 0.20 g / cm ^3, the There is a possibility that the holding force of the holding sealing material is reduced. If it exceeds 0.60 g / cm ³ , the fibers constituting the holding sealing material may be crushed, the holding force may be reduced, and the catalyst holder may be displaced due to vibration during use. .
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Reference example 1
An exhaust gas purifying catalytic converter and a manufacturing method thereof according to a reference example of the present invention will be described with reference to FIGS.
As shown in FIG. 1, an exhaust gas purifying catalytic converter 5 of this example includes a catalyst holding body 3 that can purify exhaust gas, a metal pipe 2 that covers the side surface of the catalyst holding body 3, a catalyst holding body 3, and a metal. The holding sealing material 1 is disposed between the pipe 2 and the pipe 2.
The exhaust gas purification catalytic converter 5 is provided in the middle of the exhaust pipe of the engine.
[0022]
The two metal pipes 2 are each made of SUS409 and have a thickness of 1.5 mm and a length of 60 mm. As shown in FIG. 4, the metal pipe 2 is a substantially cylindrical body, and the entire side surface gradually expands from one end to the other end. The inner diameter of the end of the tube expansion side 27 is 146 mm, and the inner diameter of the end of the opposite side 29 is 138 mm.
The holding sealing material 1 is made of a crystalline alumina fiber mat, has a thickness of 12 mm, and a bulk density of 0.1 g / cm ³ .
[0023]
The catalyst holding body 3 is a cordierite monolith that is a kind of ceramic, and supports a catalyst such as platinum that can purify the exhaust components of the exhaust gas. The outer shape of the catalyst carrier 3 is 130 mm and the length is 100 mm.
The catalyst holding body 3 is a honeycomb structure composed of an aggregate of a large number of cells that are open on the upstream side or downstream side of the exhaust system and closed on the other side. The catalyst holder allows exhaust gas to pass through the porous cell wall from the upstream open cell to the downstream open cell. At this time, exhaust gas components contained in the exhaust gas are purified by the catalyst.
[0024]
Next, a method for manufacturing the exhaust gas purifying catalytic converter of this example will be described.
As shown in FIG. 2, the holding sealing material 1 is cut into a long body having a width of 40 mm and a length of 445 mm, and recesses that engage with each other when the catalyst holding body is wound on both ends thereof. 11 and the convex part 12 are formed.
[0025]
Next, as shown in FIG. 3, the two holding sealing materials 1 are wound around the outer periphery of the catalyst holding body 3, and the concave portion 11 and the convex portion 12 are abutted to form a wound body 6. The concave portion 11 and the convex portion 12 are fixed with the adhesive tape 4. The gap C between the two holding sealing materials 1 is about 10 mm.
[0026]
Next, as shown in FIG. 4, the metal pipe 2 is expanded in a funnel shape, and the entire side surface is defined as an expanded portion 28. The gradient D of the expanded portion 28 with respect to the axial direction of the metal pipe 2 is 4 °. The expanded side 27 of the two metal pipes 2 faces the wound body 6, and these are arranged on both sides of the wound body 6.
[0027]
Next, as shown in FIG. 1, using a hydraulic press, the two metal pipes 2 are advanced to the tube expansion side 27, the wound body 6 is press-fitted therein, and the tube expansion sides 27 of the metal pipe 2 are butted together. . The press-fit load was 1960 N, and the packing density of the holding sealing material 1 after the press-fit was 0.3 g / cm ³ .
Thus, the exhaust gas purifying catalytic converter 5 is obtained.
[0028]
Embodiment 1
In this example, as shown in FIG. 6, one end face 19 in the width direction of the holding sealing material 1 is cut off at an angle of 45 °, and this is wound around the catalyst holding body 3 in the same manner as in the first embodiment. Press fit into two metal pipes.
The press-fitting load is 1764 N, and the filling density of the holding sealing material after press-fitting is 0.3 g /
[0029]
Reference example 2
The width of the holding sealing material was 90 mm, and only one member, not two members, was wound around the catalyst holder and press-fitted into the two metal pipes as in the first embodiment. Although the catalyst holder could be press-fitted into the metal pipe, the holding seal material protruded outward from the expanded side of the metal pipe during the press-fitting, and the press-fitting workability was higher than in the first and second embodiments. It was low.
[0030]
Comparative Example 1
Although the press-fitting operation was performed without expanding one side of the metal pipe, the end of the holding sealing material on the press-fitting side was turned up and could not be press-fitted.
[0031]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, it is excellent in the assembly | attachment property of the catalyst holding body to a metal pipe, and can provide the catalytic converter for exhaust gas purification which considered the influence on an environment, and its manufacturing method.
[Brief description of the drawings]
1 is a cross-sectional explanatory view of an exhaust gas purifying catalytic converter of Reference Example 1. FIG.
FIG. 2 is a development view of a holding sealing material in Reference Example 1.
3 is a perspective view of a wound body in Reference Example 1. FIG.
FIG. 4 is a perspective view of a metal pipe whose entire side surface is expanded in the present invention.
FIG. 5 is a perspective view of a metal pipe expanded from the middle of a side surface in the present invention.
6A is a plan view and FIG. 6B is a side view of a holding sealing material according to Embodiment 1;
[Explanation of symbols]
1. . . Holding sealing material,
19. . . End face,
2. . . Metal pipes,
27. . . Expansion side,
28. . . Expansion section,
29. . . The other side,
3. . . Catalyst support,
4). . . Adhesive tape,
5). . . Exhaust gas catalytic converter,
6). . . Wound body,

Claims (6)

A catalyst holding body in which a catalyst for purifying exhaust gas is supported on a carrier, a metal pipe covering the outside of the catalyst supporting body, and a holding seal interposed between the catalyst supporting body and the metal pipe In the manufacturing method of the catalytic converter for exhaust gas purification comprising
Cutting off one end face in the width direction of the holding sealing material made of an inorganic fiber mat so as to have an angle, and winding the holding sealing material around the outer periphery of the catalyst holding body to obtain a wound body;
Disposing two metal pipes having one end portion expanded in a funnel shape on both sides of the wound body with the expanded side of the metal pipe facing the wound body;
Press-fitting the wound body into the metal pipe;
A method of manufacturing a catalytic converter for purifying exhaust gas, comprising the step of fixing the expanded sides of the metal pipe.   2. The method for manufacturing an exhaust gas purifying catalytic converter according to claim 1, wherein a filling density of the holding sealing material before press-fitting the metal pipe is 0.1 to 0.2 g / cm <3>.   3. The method for manufacturing an exhaust gas purifying catalytic converter according to claim 1, wherein the inorganic fiber mat constituting the holding sealing material is made of crystalline alumina fibers.   The holding sealing material according to any one of claims 1 to 3, wherein the holding sealing material includes two members, and a gap between the members when the both members are wound around the catalyst holding body is 3 mm or more. Of manufacturing a catalytic converter for purifying exhaust gas.   An exhaust gas purifying catalytic converter produced by the method according to any one of claims 1 to 4.   6. The exhaust gas purifying catalytic converter according to claim 5, wherein a packing density of the holding sealing material in the metal shell is 0.20 to 0.60 g / cm <3>.

Images