JPH04290552A - Metallic catalyst carrier - Google Patents

Abstract

PURPOSE:To prevent short-circuit of current in a catalyst carrier provided on exhaust gas line of automobile. CONSTITUTION:The thin plate 2 made from a ceramics such as cordierite is inserted into each layer interphase 1A of a winded metallic corrugated plate 1 and each ceramic thin plate 2 is fixed with each described metallic corrugated plate 1 at each described layer interphase 1A. Brazing or fastening is used as means of fixation to integrate. Plural metallic catalyst carries made by inserting the ceramic thin plate into each layer interphase of the winded metallic corrugated plate and by fixing described metallic plate with each ceramic thin plate is connected with an insulating material.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a metal catalyst carrier installed in an automobile exhaust system, and more particularly to a pre-metallic catalyst carrier for use as a countermeasure against emissions during cold starts.

0002

[Prior Art] Conventionally, metal catalyst carriers installed in the exhaust system of automobiles include, for example, long flat metal plates and long corrugated metal plates that are alternately laminated and wound. There are two methods: one in which flat metal plates of a certain length and corrugated metal plates of a predetermined length are laminated alternately, one in which a flat metal plate is inserted between each layer of a single corrugated metal sheet that is folded in a zigzag manner, It is known that corrugated metal plates are inserted between each layer of a single flat metal plate. In each case, the abutting portions of the flat metal plate and the corrugated metal plate are fixed by spot welding, laser welding, brazing, or the like.

Recently, countermeasures against cold start emissions, especially CH, have been called for, and for example, 19
In 1990, the US SAE publication No. 900503 “Re
cent Developments in Elect
Rally Heated Metal Mono
William A. Whitten
berger CametCo. ) and JP-A-2-223
As disclosed in Publication No. 622, etc., a pre-metallic catalyst carrier placed upstream of a normal catalyst carrier (regardless of whether it is made of metal or ceramics) is electrically heated to increase the catalytic activity during startup. Attempts are being made to do so.

In particular, in the case of metal catalyst carriers, the F of the base material is
Since e, Cr, and Al alloys have been used as heaters for a long time, it is possible to raise the temperature by passing electricity directly to the metal catalyst carrier, and it is now possible to heat it using other heaters or PTC. It can be carried out very efficiently compared to other methods. FIG. 5 shows an example of this, in which an electrode 31 is formed in the center of a honeycomb-shaped metal catalyst carrier 30 made of stainless steel, and an electrode 32 is formed on the outer surface, so that electricity can be passed between these electrodes 31 and 32. is equipped with a power source 33 and a switch 34.

[0005] When the switch 34 is turned on, the metal catalyst carrier 30 itself is energized and can generate heat. Under such circumstances, it is desired that the pre-catalyst carrier be made of a metal catalyst carrier.

[0006]

[Problem to be Solved by the Invention] However, when a pre-catalyst carrier is constructed using a metal catalyst carrier as described above, if the carrier has a certain cell density, the current density in the center becomes large and uniform heating cannot be achieved. There's a problem. However, when heating the entire catalyst through electric current, the problem of insulation is a bottleneck, and a durable insulation structure has not yet been established.

That is, when manufacturing a metal catalyst carrier,
Since the metal flat plate and the metal corrugated plate are fixed together, even if an insulating layer is formed with a wash coat, the current may short-circuit through the fixed part of the metal flat plate and the metal corrugated plate. Alternatively, the insulating layer formed by the wash coat may be destroyed by thermal expansion, causing the flat metal plate and the corrugated metal plate to come into contact, causing a short circuit in the current through this area, and causing damage to all components of the metal catalyst carrier. It is not possible to electrically heat the flat metal plate and the corrugated metal plate. Furthermore, the fixed portion between the flat metal plate and the corrugated metal plate may cause the wash coat to peel off due to thermal expansion during heating.

As a result, it has not been able to function satisfactorily as a pre-catalyst carrier. Therefore, the inventor
Considering the mechanical strength, ease of production, and ease of electrical processing as a metal catalyst carrier, it was discovered that the above-mentioned problems could be solved by using a single metal corrugated sheet folded in a zigzag manner, and the present invention was developed. It has been completed.

The present invention was made based on the findings of the present inventors, and its purpose is to provide a metal catalyst carrier that can prevent short circuits of current.

0010

[Means for Solving the Problems] Claim 1 is a method of interposing a ceramic thin plate between each layer of a single corrugated metal plate, and connecting each ceramic thin plate and the metal corrugated plate. , which are fixedly bonded between each of the above layers. According to a second aspect of the present invention, in the first aspect, the ceramic thin plate is made of cordierite.

[0011] According to a third aspect of the present invention, in the first or second aspect, the metal corrugated plate and each ceramic thin plate are brazed. According to a fourth aspect of the present invention, in the first or second aspect, the metal corrugated plate and each ceramic thin plate are integrally fixed by lashing. According to a fifth aspect of the present invention, a ceramic thin plate is inserted between each layer of a single corrugated metal plate, and the metal corrugated plate and each ceramic thin plate are fixed between each layer. It consists of a plurality of metal catalyst carriers connected through an insulator.

0012

[Operation] According to claims 1 to 4, the meandering 1
When a current is applied to one end of the corrugated metal sheets, the layers facing each other are electrically insulated by the thin ceramic plates inserted between the layers of the corrugated metal sheets, so the corrugated metal sheets are electrically insulated. It flows through the metal corrugated plate without shorting between each layer.

[0013] In claim 5, when a current is applied from one end side of the single metal corrugated plate folded in a serpentine manner, electric current flows through the zigzag folded metal corrugated plate for each metal catalyst carrier. Current flows without short-circuiting, and no current flows to adjacent metal catalyst carriers.

[0014]

Embodiments Hereinafter, embodiments of the present invention will be explained based on the drawings. FIGS. 1 and 2 show an example of a metal catalyst carrier according to a first aspect of the present invention, and 1 represents one metal corrugated plate that is folded in a zigzag manner. This long metal flat plate 1 is made by folding a long metal flat plate wound in a coil shape by any method and making it into a corrugated sheet shape. It is shaped by processing. The single corrugated metal sheet 1 is made of an alloy of Fe, Cr, and Al, similar to those used for ordinary metal catalyst carriers.

[0015] Also, one piece of metal corrugated plate 1 is folded in a zigzag manner.
A thin ceramic plate 2 made of cordierite or the like having a small thermal expansion is inserted between each layer 1A. Each interlayer 1A of the single corrugated metal plate 1 that has been folded in a zigzag manner and each ceramic thin plate 2 are fixed to each other. Examples of this fixing method include the following. (1) Active brazing or metal brazing containing Ti is applied to the surface of each ceramic thin plate 2, and each ceramic thin plate 2 is fixed to each interlayer 1A of one metal corrugated plate 1 folded in a zigzag manner by brazing. do. (2) Between each layer 1 of one metal corrugated sheet 1 folded in a zigzag manner
After inserting a ceramic thin plate 2 made of cordierite or the like with small thermal expansion into A, each of the metal corrugated plates 1 is folded in a zigzag manner by mechanically pressing and securing the periphery with a band plate or the like. The interlayer 1A and each ceramic thin plate 2 are fixed.

In this embodiment constructed in this manner, when a current is applied from one end side of one corrugated metal sheet 1, the electric current is inserted between each layer 1A of the corrugated metal sheet 1. Since the opposing layers 1a are electrically insulated by the ceramic thin plate 2, the flow flows through the metal corrugated plate 1 without shorting between the opposing layers 1A. As a result, the entire corrugated metal sheet 1 is electrically heated.

Therefore, for example, the metal catalyst carrier 10 according to this embodiment can be used as a normal catalyst carrier (regardless of whether it is made of metal or ceramic) installed in the exhaust system 12, as shown in FIG.
13 on the upstream side. When the metal catalyst carrier 10 is heated by applying electricity when starting the engine 11, the temperature can be raised to 300 to 500° C. in a short time, and the catalyst activity can be increased.

As described above, according to the present embodiment, the ceramic thin plates 2 are inserted between each layer 1A of one metal corrugated plate 1 that is folded in a zigzag manner, and the ceramic thin plates 2 and the metal Since the corrugated plate 1 is fixed to the metal corrugated plate 1 with 1A between each of the layers, when electricity is applied, the current flows through the metal corrugated plate 1 and heats the entire body without shorting the 1A between the opposing layers. Can be done. Further, since a thin ceramic plate 2 made of cordierite or the like having a small thermal expansion is inserted as an insulating material, peeling of the wash coat can be reduced. Furthermore, insulation is ensured.

FIG. 4 shows an example of a metal catalyst carrier according to claim 5. In this example, two metal catalyst carriers 10 formed according to the above example are connected via an insulator 20. In this embodiment, when a current is applied from one end side of a single corrugated metal plate 1 that is folded in a zigzag manner, the electric current flows through the corrugated metal plate 1 that is folded in a zigzag manner to each metal catalyst carrier 10. current flows without shorting,
No current flows through adjacent metal catalyst carriers 10. As a result, the entire metal corrugated plate 1 is electrically heated for each metal catalyst carrier 10.

As described above, according to this embodiment, the ceramic thin plate 2 is inserted between each layer 1A of one corrugated metal plate 1 that is folded in a zigzag manner, and the ceramic thin plate 2 is inserted between the metal corrugated plate 1 and each ceramic layer. Since the two metal catalyst carriers 10, which are formed by fixing the thin plates 2 and the thin plates 2 with each other with the interlayer gap 1A, are connected via the insulator 20, in addition to producing the same effects as in the embodiment described above, multiple catalyst carriers can be used simultaneously. Since the metal catalyst carrier 10 can be heated, the emission during cold start, especially the purification performance of CH, can be significantly improved.

In the above embodiment, the case where two metal catalyst carriers 10 are connected has been described, but the number of metal catalyst carriers 10 to be connected can be determined as appropriate, taking into consideration the size, capacity, etc. of the exhaust system.

[0022]

[Effects of the Invention] As explained above, according to claims 1 to 5, the insulation between each layer of a single metal corrugated sheet folded in a zigzag manner is ensured, and current can be passed between each layer without causing a short circuit. This makes it possible to effectively utilize the entire metal catalyst carrier. Further, since the ceramic thin plate inserted between each layer of the single corrugated metal plate has a small thermal expansion, peeling of the wash coat can be reduced.

Further, according to claim 5, it is possible to connect a plurality of metal catalyst carriers, and the catalyst activity at the time of cold start can be improved.

[Brief explanation of the drawing]

FIG. 1 is an explanatory diagram showing essential parts of the metal catalyst carrier shown in FIG. 2. FIG.

FIG. 2 is an end view showing an example of a metal catalyst carrier according to claim 1.

FIG. 3 is an explanatory diagram showing an exhaust system to which the metal catalyst carrier of FIG. 2 is attached.

FIG. 4 is an explanatory diagram showing an example of a metal catalyst carrier according to claim 5.

FIG. 5 is a perspective explanatory view showing an example of a conventional metal catalyst carrier.

[Explanation of symbols]

1 One metal corrugated plate 1A folded in a zigzag manner 2 Between each layer 2 Ceramic thin plate 10 Metal catalyst carrier 20 Insulator

Claims (5)

[Claims] [Claim 1] A single corrugated metal plate (
A ceramic thin plate (2) is inserted between each layer (1A) of 1), and each ceramic thin plate (2) and the metal corrugated plate (1) are fixed between each layer (1A). A metal catalyst carrier characterized by comprising: 2. The metal catalyst carrier according to claim 1, wherein the thin ceramic plate (2) is made of cordierite. 3. The metal catalyst carrier according to claim 1, wherein the metal corrugated plate (1) and each ceramic thin plate (2) are brazed together. 4. According to claim 1 or 2, the metal corrugated plate (1) and each ceramic thin plate (2) are integrally fixed by lashing. Metal catalyst carrier. [Claim 5] A single corrugated metal plate (
A ceramic thin plate (2) is inserted between each layer (1A) of 1), and the metal corrugated plate (1) and each ceramic thin plate (2) are fixed between each layer (1A). A metal catalyst carrier comprising a plurality of metal catalyst carriers (10) connected through an insulator (20).