JPH05184938A - Current supply heating type catalyst converter - Google Patents

Abstract

(57) [Abstract] [Purpose] To facilitate electrical connection from the metal catalyst carrier to the outside of the metal case and reduce the flow resistance in the catalytic converter. [Structure] A metal catalyst carrier 3 in which a corrugated plate having insulating coatings formed on both sides and a flat plate are overlapped and rolled up is formed into a metal case 5.
It is inserted into the case 5 and fixed to the case 5 so that it can be energized, and an electrode (not shown) is connected to the outer peripheral surface of the case 5. In the joining region 3b of the catalyst carrier 3, the corrugated plate and the flat plate are joined in a conductive manner, and in the non-joining region 3a, the corrugated plate and the flat plate are not joined. The axial length b of the non-bonded region 3a is the axial length L of the bonded region 3b.
1/2 of that.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrically heated catalytic converter.

[0002]

2. Description of the Related Art U.S. Pat. No. 3,770,389 discloses a metallic catalyst carrier in which a metal corrugated sheet having insulating coatings on both sides and a flat plate are superposed and wound to form alternate layers of the corrugated sheet and the flat plate. The cylindrical electrode is connected to the center of the metal catalyst carrier and the cylindrical electrode is connected to the outer periphery of the metal catalyst carrier, and the ceramic catalyst carrier surrounding the metal catalyst carrier is fitted to the metal catalyst carrier and the ceramic catalyst carrier is fitted. Disclosed is an electrically heated catalytic converter in which a catalyst carrier is fitted in a case of a catalytic converter so that a metal catalyst carrier is energized to generate heat.

[0003]

However, in this catalytic converter, since the pair of electrodes are both arranged in the catalytic converter case, the flow passage cross-sectional area in the catalytic converter is reduced and the exhaust gas flow resistance is increased. At the same time, there is a problem that the electrical connection from the electrode to the outside of the catalytic converter case becomes troublesome.

[0004]

In order to solve the above problems, according to the present invention, only a partial region of the metal catalyst carrier is heated by energizing the metal catalyst carrier made of the same metal material. Then, the metal catalyst carrier is fitted into the metal case of the catalytic converter to be electrically connected to the metal case, and the metal case is provided with an electrode so that the heat capacity of a part of the area can be increased by a metal catalyst other than the part of the area. It is smaller than the heat capacity of the region of the carrier.

[0005]

[Function] Since the metal catalyst carrier is electrically connected to the metal case and the metal case is provided with the electrodes,
The cross-sectional area of the flow path in the catalytic converter increases, and the electrical connection from the metal catalyst carrier to the outside of the metal case becomes easy. Further, since the heat capacity of the partial area that is the heat generating area is made smaller than the heat capacity of the area other than the partial area, the temperature rising rate of the partial area increases, and when the same metal material is used, the heat capacity is small. Since a part of the region has a smaller flow resistance than a region other than the part having a large heat capacity, a large amount of exhaust gas flows in the part of the region.

[0006]

EXAMPLE A first example will be described with reference to FIGS. First, referring to FIG. 3, a thin metal corrugated plate 1 and a flat plate 2 are stacked and wound around a positive electrode 4 as a center to form spiral alternating layers to form a honeycomb metallic catalyst carrier 3 Is formed. The corrugated plate 1 and the flat plate 2 are
For example, it is a foil material having a composition of 20% Cr-5% Al-75% Fe and a plate thickness of about 50 μm. On both sides of the corrugated sheet 1 and the flat plate 2 is coated is Al ₂ O ₃ is an insulating film, a noble metal such as platinum, palladium, rhodium or the like is impregnated in the catalyst on the film of the Al ₂ O _3.

At the positions where the corrugated plate 1 and the flat plate 2 correspond to each other, the axial length of the catalyst carrier 3 increases from b to L. Therefore, as shown in FIG. 1, the axial length b of the central cylindrical region 3a of the catalyst carrier 3 is shorter than the axial length L of the outer peripheral cylindrical region 3b, and b is about 1 of L. / 2. The diameter d of the outer circumference of the central cylindrical region 3a is about ½ of the diameter D of the outer circumference of the outer cylindrical region 3b.

Referring to FIGS. 1 and 2, the catalyst carrier 3
The positive electrode 4 is arranged along the axis of the center of the
The positive electrode 4 is electrically connected to the catalyst carrier 3. The catalyst carrier 3 is inserted into a metal cylindrical case 5 and fixed to the case 5 by brazing, for example, and the catalyst carrier 3 can be electrically connected to the case 5. As shown in FIG. 2, the negative electrode 6 is connected to the side surface of the case 5. As shown in FIG. 1, the positive electrode 4 extends in the axial direction of the case 5, is then bent into an L-shape, extends in the diameter direction of the case 5, and penetrates the side surface of the case 5. The positive electrode 4 is electrically insulated from the case 5 by the insulating material 7.

In the outer peripheral cylindrical region 3b of the catalyst carrier 3, the peaks and troughs of the corrugated plate 1 and the flat plate 2 are electrically connected to each other by, for example, brazing, discharge welding or laser welding. On the other hand, in the central cylindrical region 3a, the corrugated plate 1 and the flat plate 2 are not joined, and therefore the corrugated plate 1 and the flat plate 2 are insulated by the insulating coating Al ₂ O ₃ .
Therefore, in the following, the central and outer peripheral cylindrical regions 3a, 3 will be described.
b are referred to as a non-bonding region 3a and a bonding region 3b, respectively.

The non-bonded regions 3a and the bonded regions 3b are made of the same metal material, and the number of passages (hereinafter referred to as "cells") formed by the corrugated plate 1 and the flat plate 2 per unit cross-sectional area. (Hereinafter, "Number of cells per unit cross-sectional area")
"), The non-bonding region 3a and the bonding region 3b are almost equal. Therefore, as is clear from FIG. 1, the mass of the non-bonding region 3a is about 1/6 of the mass of the bonding region 3b, and the heat capacity of the non-bonding region 3a is about 1/6 of the heat capacity of the bonding region 3b.

Further, since the axial length b of the non-bonding region 3a is about 1/2 of the axial length L of the bonding region 3b, the flow resistance of the non-bonding region 3a is greater than that of the bonding region 3b. As shown in the left side of FIG. 1, the exhaust gas flow velocity distribution becomes higher in the non-bonding region 3a. Therefore, a large amount of exhaust gas flows in the non-bonding area 3a. In the joining region 3b, since the corrugated plate 1 and the flat plate 2 are connected so as to be able to conduct electricity, the electric resistance value is low, and therefore almost no heat is generated. On the other hand, in the non-bonding region 3a, since the corrugated plate 1 and the flat plate 2 are insulated, the current path is formed in a spiral shape along the corrugated plate 1 and the flat plate 2 and becomes long, so that the electric resistance value is growing. Therefore, the non-bonding region 3a generates heat when energized and becomes a heat generating portion.

Therefore, when a voltage is applied between the positive electrode 4 and the negative electrode 6, the non-junction region 3a generates heat. As described above, since the heat capacity of the non-bonding region 3a is small, the temperature rising rate of the non-bonding region increases and the temperature rises rapidly. Further, as described above, since a large amount of exhaust gas flows in the non-bonding region 3a,
This also heats the non-bonded area. As a result, the exhaust gas can be purified early and effectively. Further, since the heat generating portion (non-bonding area 3a) has a small heat capacity, it is possible to reduce power consumption.

As described above, according to this embodiment, the catalyst carrier 3 is inserted into the metal case 5 and fixed to the metal case 5 so that electricity can be conducted, and the negative electrode 6 is connected to the side surface of the metal case 5. Therefore, as compared with the case where the negative electrode is provided in the case 5, the flow passage cross-sectional area can be increased and the flow resistance can be reduced, and the electrical connection from the catalyst carrier 3 to the outside of the case 5 becomes easy.

Further, since the non-bonding region 3a has a smaller heat capacity and a larger exhaust gas flow rate per unit cross-sectional area than the bonding region 3b, the exhaust gas can be purified early and effectively, and the power consumption is reduced. It can be reduced. Further, since the outer peripheral portion of the catalyst carrier 3 where a relatively large thermal stress is generated is joined, the catalyst carrier 3 is less likely to be displaced in the axial direction and the strength can be improved.

Next, a second embodiment will be described with reference to FIGS. 4 and 5. The second embodiment is similar to the first embodiment except that the structure of the catalyst carrier 3 is different from that of the first embodiment. Referring to FIGS. 4 and 5, the inner peripheral portion 3c is a non-bonding region and the outer peripheral portion 3d is a bonding region. Figure 5
As shown in (3), both the non-bonding region 3c and the bonding region 3d have the same axial length of l.

The thicknesses of the corrugated sheet 1 and the flat plate 2 in the non-bonded area 3c are made thinner than those of the corrugated sheet 1 and the flat plate 2 in the bonded area 3d, whereby the heat capacity of the non-bonded area 3c is made considerably smaller than the heat capacity of the bonded area 3d. As a result, the flow resistance also decreases. As a result, it is possible to obtain the same effects as those of the first embodiment. It should be noted that while keeping the plate thicknesses of the non-bonding region 3c and the bonding region 3d equal, the number of cells per unit cross-sectional area in the non-bonding region 3c is set to be smaller than the number of cells per unit cross-sectional area in the bonding region 3d. The flow resistance may be reduced.

FIGS. 6 and 7 show a third embodiment which differs from the second embodiment only in the junction area. Referring to FIGS. 6 and 7, the central portion 3f and the outer peripheral portion 3g are the joining regions, and the annular region 3e between these joining regions is the non-joining region. Also in this embodiment, the plate thickness in the non-bonded region 3e is thinner than the plate thickness in the bonded regions 3f and 3g.

According to this embodiment, purification of exhaust gas is improved particularly in the annular portion of the catalytic converter. Further, as another embodiment, it is possible to heat the bonding region only as the central portion and the outer peripheral portion as the non-bonding region. With such a structure, the exhaust gas can be satisfactorily purified particularly in the outer peripheral portion of the catalytic converter.

In the first to third embodiments described above, the catalyst carrier 3 is formed by winding the pair of corrugated plates 1 and 2 together, but as shown in FIG. The first to third embodiments may be applied to a catalyst carrier formed by winding a plurality of assembled plates 10 each including the plate 1 and the flat plate 2 around the positive electrode 4.

[0020]

The flow resistance in the catalytic converter can be increased by increasing the flow passage cross-sectional area. In addition, electrical connection from the metal catalyst carrier to the outside of the metal case becomes easy. Further, since a part of the heat generating area is rapidly heated, and a large amount of exhaust gas flows in the part of the area, the exhaust gas can be purified early and effectively.

[Brief description of drawings]

FIG. 1 is the first embodiment of the catalytic converter I shown in FIG.
It is sectional drawing seen along the -I line.

FIG. 2 is a view of the catalytic converter of FIG. 1 taken along the arrow II.

FIG. 3 is a view of forming a catalyst carrier in which a corrugated plate and a flat plate are overlapped and rolled up.

FIG. 4 is a view of the catalytic converter of the second embodiment shown in FIG. 5 as seen along the arrow IV.

5 is a cross-sectional view of the catalytic converter of FIG. 4, taken along line VV.

FIG. 6 is a view of the catalytic converter of the third embodiment shown in FIG. 7 as seen along arrow VI.

7 is a cross-sectional view of the catalytic converter of FIG. 6 taken along line VII-VII.

FIG. 8 is a view of forming a catalyst carrier by winding a plurality of assembled plates including corrugated plates and flat plates.

[Explanation of symbols]

 3 ... Metal catalyst carrier 3a ... Non-bonding region 3b ... Bonding region 5 ... Case 6 ... Negative electrode

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor ▲ Yoshi ▼ Ei Naga 14 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Stock Company Japan Auto Parts Research Institute (72) Inventor, Seihiko Watanabe 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Address: Japan Auto Parts Research Institute, Inc. (72) Inventor, Yukihiro Shinohara, 14 Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Prefecture Japan Auto Parts Research Institute, Inc. (72) Inventor, Osamu Fujishiro 14, Iwatani, Shimohakaku-cho, Nishio-shi, Aichi Bachi Stock Company, Japan Automotive Parts Research Institute

Claims (1)

[Claims] 1. A metal catalyst carrier made of the same metal material is energized so that only a partial region of the metal catalyst carrier generates heat, and the metal catalyst carrier is fitted into a metal case of a catalytic converter. At least an electric heating type, which is electrically connected to the metal case and is provided with an electrode on the metal case so that the heat capacity of the partial area is smaller than the heat capacity of the area of the metal catalyst carrier other than the partial area. Catalytic converter.