JPH08215582A - Highly durable metal carrier for exhaust gas purification - Google Patents

Abstract

(57) [Abstract] [Objective] The present invention is manufactured by applying a normal manufacturing process to a honeycomb body made of materials having different foil strengths or thicknesses, and has sufficient strength against the compressive stress of the flat foil. Provided is a highly durable metal carrier for purifying exhaust gas, which is not damaged. [Configuration] A honeycomb body formed by alternately winding and laminating a metal flat foil and a metal corrugated foil is inserted into a metal outer cylinder,
Exhaust gas characterized in that, in a metal carrier configured by being appropriately joined, the high-temperature tensile strength σ1 of the flat foil and the high-temperature tensile strength σ2 of the corrugated foil constituting the honeycomb body are configured to satisfy σ1> σ2. It is a highly durable metal carrier for purification, and in the above metal carrier, the plate thickness t1 and the high temperature tensile strength σ1 of the flat foil constituting the honeycomb body and the plate thickness t2 and the high temperature tensile strength σ2 of the corrugated foil are expressed by the following equations. It is configured to have the relationship shown. 1 <(t1 × σ1) / (t2 × σ2)

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a highly durable metal carrier for a catalyst, which is installed in an exhaust gas system for purifying exhaust gas discharged from an engine such as an internal combustion engine.

[0002]

2. Description of the Related Art Recently, a metal carrier has been used as a catalyst carrier installed to purify engine exhaust gas of an automobile or a two-wheeled vehicle. The metal carrier is composed by stacking a flat foil made of heat-resistant metal and a corrugated foil obtained by processing this into a corrugated form, and inserting a honeycomb body that is wound and laminated in a spiral shape into an outer cylinder made of the heat-resistant metal. The flat foil and the corrugated foil, and the honeycomb body and the outer cylinder are mainly joined with a brazing material. Such a honeycomb body carries a catalytic metal such as Pt, which comes into contact with exhaust gas and purifies gas components.

A metal carrier installed in an exhaust gas system of an automobile or a two-wheeled vehicle must appropriately join a flat foil and a corrugated foil forming a honeycomb body, and a honeycomb body and an outer cylinder in order to withstand vibration during operation. I have to. Further, the honeycomb body comes into direct contact with high-temperature exhaust gas, and the temperature becomes high due to heat generation due to the catalytic reaction, but the outer cylinder is exposed to the outside air and radiates heat. It becomes relatively low temperature. That is, in the case where the central portion of the metal carrier has a high temperature, therefore, thermal stress is generated on the inside and outside in the radial direction due to the temperature difference, and when the outer cylinder having a large wall thickness and the honeycomb body are integrally joined, The honeycomb body near the outer cylinder, which is weak in strength, may be damaged by thermal strain.

In order to prevent the occurrence of such damage, in Japanese Utility Model Laid-Open No. 2-25028, flat plates (foil) are lap-wound at the inner peripheral portion of the annular member of the core portion and the portion located in the vicinity thereof. Japanese Patent Laid-Open No. 5-20030
No. 9 discloses that a front end of a honeycomb carrier is coated with a water-repellent masking agent over a predetermined length, and then the carrier is dipped in a coating liquid to impregnate a catalyst, and a predetermined length from the front end of the honeycomb body is reached. It is disclosed that the thermal stress repeatedly applied is reduced and the occurrence of cracks is prevented by the catalyst metal carrier which constitutes the portion where the catalyst is not exposed.

However, there is a problem in that it is difficult to reliably bond the flat foils when the former two flat foils are wound, and the latter water-repellent masking treatment is a common manufacturing process. On the other hand, a process is added, the cost burden becomes large, and practical problems such as peeling of the masking agent remain.

The damage of the honeycomb body is based on the thermal strain acting on the honeycomb body restrained by the outer cylinder. For example, as shown in FIG. 2, the flat foil 1 is applied to the flat foil 1 rather than the flexible corrugated foil 2. A compressive stress causes a crack in the form of division 3.

[0007]

SUMMARY OF THE INVENTION The present invention is intended to solve such a conventional problem, in which a honeycomb body is manufactured by using materials having different foil strengths or foil thicknesses and applying ordinary manufacturing processes. However, it is an object of the present invention to provide a highly durable metal carrier for exhaust gas purification that has sufficient strength against the compressive stress of a flat foil and is not damaged.

[0008]

In order to achieve the above object, the present invention provides (1) a honeycomb body formed by alternately winding and laminating a metal flat foil and a metal corrugated foil. In the metal carrier which is inserted into the outer cylinder of and is appropriately bonded, the high temperature tensile strength σ1 of the flat foil forming the honeycomb body
And a high temperature tensile strength σ2 of the corrugated foil are configured so that σ1> σ2. (2) A highly durable metal carrier for exhaust gas purification, (2) In the above metal carrier, a honeycomb body is formed. Flat foil thickness t1 and high temperature tensile strength σ
1 is a highly durable metal carrier for purifying exhaust gas, wherein 1 and the plate thickness t2 of the corrugated foil and the high temperature tensile strength σ2 are configured to have the relationship shown in the following formula. 1 <(t1 × σ1) / (t2 × σ2)

[0009]

The present invention will be described in detail below. The corrugated foil forming the honeycomb body is a metal flat foil processed into a wave having a constant pitch, and the corrugated plate and the flat plate are superposed and wound to form a honeycomb body. At this time, the peaks of the crests (valleys) of the corrugated foil contact the surface of the flat foil. When the metal carrier, which is constructed by inserting the honeycomb body into the outer cylinder, is placed in the exhaust gas system and used, the contact portion of the corrugated foil and the flat foil must be joined so that the honeycomb body does not pop out in a telescopic shape. Instead, soldering is usually performed.

According to the present invention, in such a honeycomb structure, the tensile strength of the flat foil, which is easily affected by thermal stress and easily broken, is increased. That is, as shown in FIG. 3, by configuring the honeycomb body so that σ1> σ2 in the relationship between the high temperature tensile strength σ1 of the flat foil 1 and the high temperature tensile strength σ2 of the corrugated foil 2 in the honeycomb body, as shown in FIG. Prevent the flat foil from breaking.

The high temperature tensile strength is the tensile strength when the metal carrier is exposed to a high temperature exhaust gas, and the strength at around 600 ° C. is usually used as a reference. In order to impart such high temperature strength, the solid solution strengthening elements Mo, T
A foil having various strengths can be obtained by adding a, W or the like, or by adding precipitation strengthening elements V, Nb or the like.

On the other hand, by defining the foil thickness, it becomes possible to prevent breakage as in the above-mentioned high temperature tensile strength regulation. That is, as shown in FIG. 1, when the flat foil 1 and the corrugated foil 2 have substantially the same high-temperature tensile strength per unit area, the thickness t1 of the flat foil 1 and the corrugated foil thickness t2 are t1> t2. It is preferable that the honeycomb body is configured such that the relationship is satisfied, or 1 <(t1 × σ1) / (t2 × σ2). In order to increase the absolute strength of the flat foil used for the honeycomb body, the plate thickness may be made larger than that of the corrugated foil.

[0013]

EXAMPLE A flat foil and a corrugated foil having the thickness shown in Table 1 and high temperature tensile strength at 600 ° C. were used. The corrugated foil had a wave height of 1.25 mm and a wave pitch of 2.5 mm. A honeycomb body having a diameter of 100.3 mm was wound and produced. This honeycomb body is pressed into a metal outer cylinder with a plate thickness of 1.5 mm and an inner diameter of 100 mm,
A metal carrier having a diameter of 100.3 mm and a length of 103 mm as shown in FIG. 3 was used.

To evaluate the durability of each metal carrier shown in Table 1, a 2000 cc engine was used and test metal carriers were
1000 cycles of heating at a gas temperature of 850 ° C. for 10 minutes and then cooling to room temperature were carried out. The results are also shown in Table 1.

[0015]

[Table 1]

[0016]

INDUSTRIAL APPLICABILITY As described above, according to the present invention, a honeycomb body is manufactured from materials having different foil strengths or foil thicknesses by applying a normal manufacturing process, and has sufficient strength against the compressive stress of the flat foil. However, it is possible to easily and inexpensively provide a highly durable metal carrier that is not damaged.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a partial cross section of a honeycomb body of the present invention.

FIG. 2 is an explanatory view showing a part of a conventional honeycomb body.

FIG. 3 shows a perspective view of a metal carrier.

[Explanation of symbols]

 1: Flat foil 2: Corrugated foil 3: Broken part (crack) 4: Honeycomb body 5: Outer cylinder 6: Metal carrier

Claims (2)

[Claims] 1. A metal carrier constituted by inserting and appropriately joining a honeycomb body formed by alternately winding and laminating a metal flat foil and a metal corrugated foil into a metal outer cylinder. A high durability metal carrier for exhaust gas purification, characterized in that the flat foil constituting the honeycomb body has a high temperature tensile strength σ1 and a corrugated foil has a high temperature tensile strength σ2 such that σ1> σ2. 2. A metal carrier formed by inserting and appropriately joining a honeycomb body formed by alternately winding and laminating a metal flat foil and a metal corrugated foil into a metal outer cylinder. Exhaust gas purification characterized in that the plate thickness t1 and the high temperature tensile strength σ1 of the flat foil and the plate thickness t2 and the high temperature tensile strength σ2 of the corrugated foil constituting the honeycomb body are configured to have the relationship shown in the following formula. High durability metal carrier for. 1 <(t1 × σ1) / (t2 × σ2)