JPH04358544A - Catalyst carrier - Google Patents

Abstract

PURPOSE:To provide a catalyst carrier generating no crack or release by the temp. gradient at the time of the passage of exhaust gas. CONSTITUTION:A catalyst carrier is constituted by laminating corrugated plates 1 and flat plates 2 gas passages permitting exhaust gas to pass are formed to the corrugated plates 2. The corrugated plates 1 and flat plates 2 are mutually soldered and fixed only at one places in the passage direction (S-parts) and the fixed parts S are positionally shifted in the laminating direction. Even when a temp. gradient is generated in the passing direction of exhaust gas, the corrugated plates and the flat plates 2 respectively independently and freely extend to generate no crack. With respect to the temp. gradient in the laminating direction, the flat plates 2 are elastically deformed to prevent the generation of stress to avoid the generation of a crack.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst carrier supporting an exhaust gas purification catalyst for a vehicle.

0002

[Prior Art] In FIG. 5, an exhaust pipe E1 of an engine E is shown.
An exhaust gas purification device C is installed in the middle of the exhaust gas purification device C, which has a honeycomb-shaped catalyst carrier 3 supporting a three-way catalyst for exhaust gas purification in a large-diameter case C1. It is something. The details of the structure of the catalyst carrier 3 are shown in FIG. 6, in which a metal corrugated sheet 1 and a flat plate 2, each carrying a catalyst on the plate surface, are laminated, and the entire upper and lower tops of the corrugated sheet 1 are placed on the surface of the flat plate 2, respectively. It is fixed by brazing. Thus, the exhaust gas flowing through the numerous channels P formed between the corrugated plate 1 and the flat plate 2 is purified by the catalyst.

0003

[Problems to be Solved by the Invention] By the way, there is a carrier 3 constructed by winding a corrugated plate 1 of a constant width and a flat plate 2 in a racetrack shape (Fig. 7), and when examining the temperature distribution of such a carrier, The temperature of the inner circumferential portion is high due to the circulation of exhaust gas, and the temperature of the outer circumferential portion rapidly decreases due to cooling by the running wind (in the x direction in the figure). Furthermore, a temperature difference occurs from the inlet side to the outlet side of the carrier 3 (in the y direction in the figure) due to the reaction heat of the catalyst. The temperature difference between these temperatures sometimes reaches 300°C.

[0004] In the conventional structure in which the corrugated sheet 1 is fixed to the flat plate 2 on the entire top surface, a difference occurs in the amount of thermal expansion in areas where there is a temperature gradient, and cracks occur in the corrugated sheet 1 and the flat sheet 2 due to the generation of stress. There was a problem that buckling occurred. The present invention solves this problem, and aims to provide a catalyst carrier that prevents the generation of stress due to temperature gradients and does not cause functional deterioration.

[0005]

[Means for Solving the Problems] To explain the structure of the present invention, a catalyst is supported on the plate surfaces of metal corrugated plates 1 (FIG. 1) and flat plates 2 which are laminated alternately, and an air flow flows through the corrugated plate space. A catalyst carrier 3 with a channel P, in which the top of the corrugated plate 1 is fixed to the flat plate 2 at one point in the flow path direction, and each fixed part S is shifted from each other in the stacking direction at least in the upper and lower adjacent layers. It is set in the position.

In the catalyst carrier 3 having such a structure, when exhaust gas flows through the air flow path P, the corrugated plate 1 constituting the carrier
A temperature gradient is generated along the flow path in the stacking direction of the flat plates 2 or from the inlet side to the outlet side, and the flat plates 1 and the corrugated plates 2 exhibit different expansion amounts at each part. Here, in the direction along the flow path, each of the plates 1 and 2 is fixed at only one place, so that they can each freely expand and contract in this direction, thereby preventing the generation of stress. Furthermore, since the fixed portions S are offset in at least the upper and lower adjacent layers in the stacking direction, the plates 1 and 2 can freely expand and contract in this direction as well, thereby preventing the generation of stress.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1(a) shows a main part of a catalyst carrier 3 according to the present invention, and shows one layer of metal corrugated plates 1 and flat plates 2 which are alternately laminated. An air flow path P having a chevron-shaped cross section is formed by the corrugated plate 1 sandwiched between the flat plates 2, and a catalyst is carried on the wall of the air flow path P to purify the exhaust gas flowing therethrough.

The top of the corrugated plate 1 is brazed and fixed to the flat plate 2 at one point in the direction of the flow path (section S in the figure), and the length m of this brazed section S (FIG. 1(b)) is It is set at 2% to 20% of the total length in the flow path direction. Furthermore, the positions of the brazed portions are shifted in the stacking direction as shown in FIG. 1(c).

An example of a method for manufacturing such a catalyst carrier 3 is shown in FIG.
Shown below. In the figure, a metal corrugated plate 1 is wound horizontally around a rotating core metal 4 (arrow in the figure), and a metal flat plate 2 is wound vertically to cover this corrugated plate 1. The corrugated plate 1 and the flat plate 2 are laminated and wound in a circle to form a catalyst carrier 3. Containers 5A and 5B holding brazing material are close to both sides of the flat plate 2 supplied from above, and a coating roller (not shown) provided in the container is in contact with the surface of the flat plate 2. The brazing material holding containers 5A and 5B are reciprocated in the left and right directions by a controller 6 via a drive mechanism in synchronization with the rotation of the core metal 4.

As a result, the brazing material is applied to both sides of the flat plate 2 in a sinusoidal manner in the supply direction (section F in the figure), and this brazing material causes the flat plate 2 to be aligned with the top of the corrugated sheet 1 in the flow path direction. It is fixed in places. The width of the brazing material is approximately 120 mm across the flat plate 2.
For example, it is about 20 mm, and the holding container 5A,
By selecting the reciprocating speed of 5B and the rotational speed of the core metal 4 and appropriately setting the period of the sine wave, the position of the brazed portion in the radial direction, that is, the stacking direction, can be shifted between the upper and lower layers.

In the catalyst carrier 3 manufactured continuously in this manner, when high-temperature exhaust gas flows through the air flow path P, a temperature gradient occurs as described above, and the amount of expansion differs in each part. In this case, since the flat plate 2 and the corrugated plate 1 are fixed only at one place in the flow path direction (S in Fig. 1(b)), a difference occurs in the expansion amounts δ and δ' of the corrugated plate 1 and the flat plate 2. Even in the case where the fibers are stretched, they elongate without restriction, and stress generation is prevented.

Furthermore, the difference in expansion due to the temperature gradient in the lamination direction is absorbed by the flat plate 2 being freely elastically deformed by shifting the position of the brazed portion S in this direction (FIG. 1(c)). , stress generation is prevented.

[0013] If the length m of the brazed portion S is 20% or more of the carrier length in the flow path direction, each plate 1,
This is not preferable because it restricts the degree of freedom of expansion of 2. If it is less than 2%, problems in terms of strength such as peeling will occur.

Instead of applying the brazing material to the flat plate 2, it may be applied to the corrugated plate 1, as shown in FIG. In the figure, the corrugated plate 1 supplied from the left side is connected to the guide roller 7.
1, 72, and the lower corrugated sheet 1 is brought into contact with the coating roller 51 of the brazing material holding container 5A provided below, and the upper corrugated sheet 1 is brought into contact with the brazing material holding container provided below. 5
The coating roller 51 of B is in contact with it. Then, each coating
A rotating shaft 52 of the roller 51 is reciprocated in the axial direction by a drive mechanism (not shown).

By this method, brazing filler metal is applied in a sinusoidal manner with a predetermined width on both sides of the corrugated plate 1 (section F in the figure), and by laminating and fixing the corrugated plate 1 to the flat plate 2, the same as in the above embodiment is obtained. A structured catalyst support 3 is produced. According to this method, since the brazing material is applied only to the top of the corrugated sheet 1, which is the fixed portion, there is no wastage of the brazing material compared to the case where the soldering material is applied to the flat plate 2, and costs are reduced.

The application of the brazing material to the corrugated plate 1 or the flat plate 2 is not limited to a sine wave shape, but any repeating shape such as a triangular wave shape as shown in FIGS. 4(a) and 4(b) may be appropriately selected. Can be done.

[0017]

As described above, according to the catalyst carrier of the present invention, internal stress is generated due to the temperature gradient caused by the flow of high-temperature exhaust gas, etc., resulting in cracking, buckling, or peeling, and the function of the catalyst is impaired. No problem of deterioration occurs.

[Brief explanation of the drawing]

FIG. 1 is a perspective view and a side view of a main part of a catalyst carrier.

FIG. 2 is a perspective view of essential parts of a catalyst carrier manufacturing apparatus.

FIG. 3 is a perspective view of main parts showing another example of a catalyst carrier manufacturing apparatus.

FIG. 4 is a plan view of the brazing material coated surface of the flat plate.

FIG. 5 is a partially sectional plan view of an engine exhaust system provided with an exhaust gas purification device.

FIG. 6 is a perspective view of essential parts of a conventional catalyst carrier.

FIG. 7 is a diagram showing the temperature distribution of a catalyst carrier.

[Explanation of symbols]

1 Corrugated plate 2　Flat plate 3 Catalyst carrier 4 Core metal 5A, 5B Brazing material container P　Airflow channel S Fixed part

Claims (1)

[Claims] Claim 1: A catalyst carrier in which a catalyst is supported on the plate surfaces of metal corrugated plates and flat plates stacked alternately, and the corrugated plate space is used as an air flow path, the top of the corrugated plate being aligned in the direction of the flow path. What is claimed is: 1. A catalyst carrier, wherein the catalyst carrier is fixed to a flat plate at one point, and each fixed portion is set at a position offset from each other in the stacking direction in at least upper and lower adjacent layers.