JPH09170429A - Metal carrier catalytic converter for controlling emission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of dislocation in a catalytic converter where an outer cylinder having a honeycomb body of which outer circumference is connected at an inner circumferential surface is connected to an exhaust pipe by connecting by welding the outer cylinder and the honeycomb body at a position other than the part where the honeycomb body and the outer cylinder is connected, thereby alleviating stress in the connection part between the honeycomb body and the outer cylinder. SOLUTION: A metal carriage 1 of a catalytic converter has an outer cylinder 3 in which a honeycomb body 2 is set, the outer circumference of the honeycomb body 2 and the inner circumferential surface of the outer cylinder 3 is connected at a downstream position 12. The honeycomb body 2 is formed of a laminated structure of a flat foil and a corrugated foil. For example one to which joining member is adhered is pressure fitted in the connection part, then soldering powder is supplied to the contact part between the flat and corrugated foil sheets and the outer cylinder 3, and it is subjected to high temp. to connect the honeycomb body 2 and the outer cylinder 3. In the metal carrier 1 the outer cylinder 3 and cone parts 4, 5 of exhaust pipe are connected 10, 11 by welding in this way, and in this case the position of the connection part 11 is taken into consideration so that no connection part 11 exist on the cross sectional surface of the connection part 12.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal carrier catalytic converter which is provided in an engine exhaust gas system such as an automobile and purifies harmful components contained in the exhaust gas.

[0002]

2. Description of the Related Art A ceramic carrier carrying a catalyst is installed in an exhaust gas system in order to purify nitrogen oxides and sulfur oxides contained in engine exhaust gas. Therefore, the use of metal carriers is increasing.

This metal carrier is connected to an exhaust gas system (pipe) by combining several members, one example of which is shown in FIG. That is, in the figure, numeral 21 is a metal carrier, and a honeycomb body 22 formed by stacking a flat plate made of a heat-resistant metal foil and a corrugated plate obtained by corrugating the flat plate and spirally winding the flat plate is press-fitted into an outer cylinder 23. The foil constituting the honeycomb body, and the outer periphery of the honeycomb body and the inner peripheral surface of the outer cylinder are fixed to each other at appropriate portions by means of a brazing material or heat diffusion. A catalyst is supported on this honeycomb body. Reference numerals 24 and 25 denote cone portions arranged in front of and behind the metal carrier 21, respectively, and the connecting pipe 2 having a predetermined diameter.
6, 27. Reference numerals 28 and 29 are flanges arranged so as to be located at the connecting portion with the exhaust gas pipe. As shown in FIG. 8 (b), each of the above-mentioned members has a cone 2 arranged in front of and behind the metal carrier 21 carrying the catalyst.
4, 25 are joined by welding, and flanges 28, 29 are joined to the tips of the connecting pipes 26, 27 of the respective cones to be integrated.

The metal carrier has an outer cylinder 21 and a cone portion 2.
4, 25 and are joined (welded) as shown in FIG. 7,
At this time, the joint 30 between the outer cylinder 21 and the cone portions 24, 25,
One or both positions of 31 are usually located at a position corresponding to the cross-sectional portion of the joint 32 between the honeycomb body 22 and the outer cylinder 21. In this way, when the joint portions 32 and 31 have the same cross section, it varies depending on the members of the cone portion and the outer cylinder due to repeated heating and cooling during operation of the engine.
Due to the difference in thermal expansion, the outer cylinder joined by the cone portion is pulled to the outside, and therefore a tensile external force is repeatedly applied between the outer cylinder and the honeycomb body, and a crack is generated in the joint portion 32 of the outer cylinder-honeycomb body. However, this gradually progresses, and the joining portion 32 is broken and peeled off, which causes a problem that the honeycomb body is displaced from the outer cylinder.

[0005] In order to solve such a problem, the actual Kaihei 3
In Japanese Patent Publication No. 1318, as shown in FIG. 6, collars 21a, 21b which are continuous with both axial ends of the outer cylinder 21 and extend axially from both ends of the honeycomb body are installed.
A catalytic converter having a structure in which 21b and the cone portions 24 and 25 are joined is proposed. However, providing the collars at both ends of the outer cylinder makes the carrier structure large, which is disadvantageous in terms of structural design and also increases the cost.

[0006]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned problems of the prior art, in which a honeycomb body is formed by selecting the joining position between the outer cylinder of the metal carrier and the cone portion or the material. An object of the present invention is to provide an inexpensive metal carrier catalytic converter for exhaust gas purification, which relieves stress at the joint of the outer cylinder and prevents the occurrence of displacement.

[0007]

In order to achieve the above object, the present invention has the following structures. That is, (1)
In a metal-supported catalytic converter in which a honeycomb body formed of a metal foil is charged, and an outer cylinder in which the outer periphery of the honeycomb body is appropriately joined at an inner peripheral surface is connected to an exhaust pipe directly or by welding with a cone connected to the exhaust pipe. A metal carrier catalytic converter for purifying exhaust gas, wherein the outer cylinder and the cone or the exhaust pipe are welded and bonded to each other at a position other than a portion where the honeycomb body and the outer cylinder are bonded. And (2) a metal in which a honeycomb body formed of a metal foil is charged, and an outer cylinder in which the outer periphery of the honeycomb body is appropriately joined at the inner peripheral surface is welded to the exhaust pipe directly or to a cone connected to the exhaust pipe. In the carrier-catalyst converter, at the portion where the honeycomb body and the outer cylinder are joined,
When welding the outer cylinder and the cone or the exhaust pipe, the material of the outer cylinder and the cone or the exhaust pipe has a coefficient of thermal expansion such that the coefficient of thermal expansion of the outer cylinder is A ≧ the coefficient of thermal expansion of the cone or the exhaust pipe B. A metal carrier catalytic converter for purifying exhaust gas, which is characterized in that And (3) the metal carrier catalytic converter for purifying exhaust gas according to the above (1) or (2), wherein the outer cylinder of the metal carrier has a flange portion or a flange portion on only one side.

As described above, by welding the outer cylinder and the cone portion (or the exhaust pipe) at the portion except the cross section of the joint portion between the outer cylinder and the honeycomb body, the stress at the joint portion of the outer cylinder and the honeycomb body is reduced. It is mitigated and the occurrence of misalignment can be prevented. In addition, when at least the joining with the cone portion is performed in the cross-section of the joining portion between the outer cylinder and the honeycomb body, a material having a smaller thermal expansion coefficient than the outer cylinder of the metal carrier or a material having the same thermal expansion coefficient as the cone is used. By using it for the portion (or the exhaust pipe), it is possible to prevent the occurrence of tensile stress in the joint portion and prevent the occurrence of displacement similarly to the above.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail with reference to the drawings. FIG. 1 is a sectional view showing an embodiment of the catalytic converter of the present invention. The metal carrier 1 is made of heat resistant steel (for example, S
The honeycomb body 2 is inserted into the outer cylinder 3 formed of US430), and the outer periphery of the honeycomb body 2 and the inner peripheral surface of the outer cylinder 3 are welded or the like at a position indicated by 12 which is a downstream portion from the central portion. It is joined. The honeycomb body 2 is a heat-resistant flat foil (for example, 20C).
r-5Al) and a corrugated foil obtained by corrugating the same are overlapped and wound or laminated in a spiral shape.
For example, a bonding material such as a brazing material is adhered to the bonding portion by press-fitting, then wax powder is supplied to the contact portion between the flat foil and the corrugated foil of the honeycomb body 2, and the honeycomb body is subjected to high temperature treatment in a vacuum furnace. Join itself and the outer cylinder. The joining method is not limited to the above, and a method using thermal diffusion treatment or high-density energy may be adopted.

In the metal carrier 1, the outer cylinder 3 and the cone portions 4 and 5 or the cone portions 4 and 5 having the exhaust pipes or the connecting pipes 6 and 7 (hereinafter, simply referred to as cone portions) are joined by welding 11. However, at this time, it is necessary to arrange the position of the joint portion 11 so that the joint portion 11 does not exist on the cross section of the joint portion 12 between the honeycomb body 2 and the outer cylinder 3. In FIG. 1, the joint portion 1 with the cone 5 is attached to the outer periphery of the outer cylinder in the non-joint portion 8 behind the joint portion 12 so as not to overlap the joint portion 12.
1 is located. As a result, even if a cone member having a coefficient of thermal expansion larger than that of the outer tubular member is used, the stress on the joint portion 12 is relieved and the joint portion 12 is not separated.

FIG. 2 shows another example of the present invention in which a part of the cone portion is omitted, in which the joint portion 12 between the honeycomb body 2 and the outer cylinder 3 is set downward, while the outer cylinder is 3 shows a state in which the joint portion 11 between the cone 3 and the cone 5 is arranged at an upper position deviated from the cross section of the joint portion 12 and joined.

FIG. 3 shows another example of the present invention in which a part of the cone portion is omitted. The joints 12a and 12b of the honeycomb body 2 and the outer cylinder 3 are set on the upper and lower end sides. On the other hand, a state is shown in which the joint portions 10 and 11 of the outer cylinder 3 and the cones 4 and 5 are arranged and joined at a central upper position deviated from the transverse cross section of the joint portion 12. That is, both FIGS. 2 and 3 are catalytic converters having the same stress relaxation structure as in FIG.

FIG. 4 shows still another example of the present invention. A flange 3a extending from the end of the honeycomb body 2 is provided at one end of the outer cylinder 3 in the axial direction. The joint portion 12 is set on the lower end side of the upper portion of the collar portion, and the joint portion 11 between the outer cylinder 3 and the cone 5 is arranged and joined to the outer cylindrical collar portion 3a deviated from the transverse cross section of the joint portion 12. It shows the state.

FIG. 5 is a cross-sectional view showing an example of another invention of the present invention. The joining mode is the same as that of FIG.
2 There is a joint portion 11 between the outer cylinder 3 and the cone 5 on the cross section, but the material used for the outer cylinder 3 and the cone portion 5 (4) is selected. The thermal expansion coefficient A of 3 is equal to or larger than the thermal expansion coefficient B of the cone member 5 (A ≧ B). By thus setting the material so that the thermal expansion is A ≧ B, the generation of tensile stress on the outer cylinder by the cone member is alleviated, the displacement of the honeycomb body is prevented, and a long-life catalytic converter is obtained. .

[0015]

【Example】

[Example 1] 20Cr-5Al-R having a thickness of 50 μm
A flat foil of EM-based heat-resistant steel and a corrugated foil obtained by processing the flat foil into a corrugated shape were overlapped and wound to form a honeycomb body having a diameter of 77 mm and a length of 100 mm. This honeycomb body was inserted into an outer cylinder of SUS430 component having a thickness of 1.5 mm and a diameter of 80 mm, and the honeycomb body and the outer cylinder were brazed by 40 mm downward from a position 40 mm away from the upper end of the outer cylinder, and 20 mm below that. Is the non-bonded part. The cone portion was formed of SUS304 having a thickness of 2 mm, and was welded and joined at a position 10 mm from the upper end and a position 10 mm from the lower end of the outer cylinder. In addition,
The coefficient of thermal expansion of SUS430 is 10 × 10 ⁻⁶ , SUS30
The coefficient of thermal expansion of No. 4 is 16 × 10 ⁻⁶ .

Comparative Example Using the same metal carrier and cone material as in Example 1, the outer cylinder and the cone were welded at a position 30 mm from the lower end of the outer cylinder.

Example 2 The same honeycomb body as in Example 1 was inserted into an outer cylinder made of SUS430, and a cone portion having the same components was welded to the outer cylinder at a position 30 mm from the lower end of the outer cylinder. The catalytic converter of each of the above examples was installed in an automobile engine exhaust gas system, and a cold-heat cyclic durability test was performed at 900 ° C. and room temperature. Examples 1 and 2 are repeated 500
The honeycomb body did not shift even during the cycle, but in the comparative example, the shift occurred after 300 cycles.

[0018]

As described above, according to the present invention, the outer cylinder and the cone portion are bonded at the non-bonded portion between the honeycomb body and the outer cylinder, or the outer cylinder and the cone portion are made of a material having the same coefficient of thermal expansion. Or by selecting and joining so that the outer cylinder is larger, the tensile stress at the joint between the outer cylinder and the honeycomb body is relaxed, and the honeycomb body does not shift from the outer cylinder It is possible to obtain an excellent catalytic converter.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of the catalytic converter of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of the present invention in which a part of a cone portion is omitted.

FIG. 3 is a cross-sectional view showing another embodiment of the present invention in which a part of the cone portion is omitted.

FIG. 4 is a cross-sectional view showing still another embodiment of the present invention in which a part of the cone portion is omitted.

FIG. 5 is a sectional view showing an embodiment of another invention of the present invention in which a part of a cone portion is omitted.

FIG. 6 is a sectional view showing a conventional catalytic converter.

FIG. 7 is an explanatory sectional view showing a conventional catalytic converter.

FIG. 8 is a conventional catalytic converter, in which (a) is an exploded view of constituent parts, and (b) is an explanatory view showing an assembled product.

[Explanation of symbols]

 1: Metal carrier 2: Honeycomb body 3: Outer cylinder 4,5: Cone part 6,7: Connection pipe 8: Non-bonded part 10, 11: Bonded part (outer cylinder-cone part) 12: Bonded part (honeycomb body- Outer cylinder)

Claims (3)

[Claims] 1. A honeycomb body formed of a metal foil is charged,
In a metal carrier catalytic converter in which an outer cylinder in which the outer periphery of the honeycomb body is appropriately joined at the inner peripheral surface is connected to the exhaust pipe directly or by welding to a cone connected to the exhaust pipe, the honeycomb body and the outer cylinder are joined together. A metal carrier catalytic converter for purifying exhaust gas, characterized in that an outer cylinder and a cone or an exhaust pipe are welded and joined at a position other than the portion. 2. A honeycomb body formed of a metal foil is charged,
In a metal carrier catalytic converter in which an outer cylinder in which the outer periphery of the honeycomb body is appropriately joined at the inner peripheral surface is connected to the exhaust pipe directly or by welding to a cone connected to the exhaust pipe, the honeycomb body and the outer cylinder are joined together. When the outer cylinder and the cone or the exhaust pipe are welded to each other at the site, the material of the outer cylinder and the cone or the exhaust pipe has a thermal expansion coefficient, and the thermal expansion coefficient of the outer cylinder is A ≧ the cone or the thermal expansion coefficient of the exhaust pipe B. A metal-supported catalytic converter for purifying exhaust gas, which is configured as follows. 3. The metal carrier catalytic converter for purifying exhaust gas according to claim 1, wherein the outer cylinder of the metal carrier has a flange on only one side.