JPH0899042A - Metal carrier for electrically heated catalytic converter - Google Patents

Abstract

(57) [Abstract] [Object] The present invention provides a metal carrier for an electrically heated catalyst device that forms a roll-shaped honeycomb body, has a simple structure and is easy to manufacture without using an electrically insulating structure, and has a low temperature and a required temperature. Provided is a heatable metal carrier. [Structure] A corrugated plate material 1 and a flat plate material 2 are superposed with an elongated brazing foil-shaped amorphous brazing material 3 and rolled to form a honeycomb body 9 which is inserted into an outer cylinder 4 to bond the contact portions. To form the metal carrier 10. Four outer peripheral electrodes 6 are provided on the outer surface of the outer cylinder 4 at equal intervals, and a voltage is applied between the outer electrode 4 and the central electrode 5 provided in the central portion of the honeycomb body 9 to heat the metal carrier 10 forming the honeycomb body 9. To be done. By increasing or decreasing the number of outer peripheral electrodes 6, a heating element having an electric resistance value corresponding to the outer diameter or axial length of the metal carrier 10 can be obtained. The metal carrier 10 does not require an electrically insulating layer.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalyst carrier metal carrier used in an exhaust gas purifying apparatus for an internal combustion engine, and more particularly to an electrically heated metal carrier carrier.

[0002]

2. Description of the Related Art A metal carrier for a catalyst device used in a conventional exhaust gas purifying apparatus has a brazing filler metal interposed between a thin metal flat plate and a corrugated plate, and the flat plate and the corrugated plate are superposed and rolled into a roll from the center. A honeycomb body is formed, a brazing material is melted using a high vacuum furnace, and joining is performed at a contact portion of the plate materials. A Ni-based brazing material was used as the brazing material, and a ferritic stainless steel material was used as the flat plate and the corrugated plate. A honeycomb carrier formed in such a manner and housed in a metal outer cylinder is known as a metal carrier for a catalyst device. (For example, JP-A-56-4373).

A catalyst supporting layer is formed on the surface of the honeycomb passage of the honeycomb body, and a noble metal catalyst is supported on the catalyst supporting layer to serve as an exhaust gas purifying catalyst. HC, CO, NO _x in the exhaust gas is provided in the exhaust passage of the internal combustion engine.
Etc. Since it is necessary to secure as large a honeycomb passage area as possible in a limited volume, the thickness of the flat plate and the corrugated plate is as thin as possible within a range in which the strength can be maintained.

Since the catalytic reaction of the noble metal catalyst supported on the catalyst supporting layer described above is promoted in a high temperature environment to a certain extent, the catalyst device is exposed to the exhaust gas at a temperature as high as possible. It is installed near the valve.

However, since the temperature of the exhaust gas is low at the time of starting the internal combustion engine, even such a catalyst device does not sufficiently perform the catalytic reaction, and therefore HC and C in the exhaust gas are not generated.
The ability to purify O, NO _x, etc. becomes insufficient. To eliminate this drawback, an electrically heated catalyst device as shown in FIG. 3 is disclosed.

In FIG. 3, a plurality of layers 53 in which a plurality of flat plate materials and corrugated plate materials are stacked are spirally wound to form a honeycomb body 5.
2, a gap 54 is present between the adjacent plural layers 53, and a plurality of rod-shaped supports 57 are arranged in the plural layers 53 to maintain the gap. The outer surface of the honeycomb body 52 is covered with an outer cylinder 56 with an electric insulating layer 55 interposed therebetween. The two conductor connecting portions A and B penetrating the outer cylinder 56 are electrically connected to both ends A ₁ and B ₁ of the spiral of the plurality of layers 53 of the honeycomb body, respectively. With the power source connected to the conductor connecting portions A and B, the honeycomb body 52 is heated by Joule heat at the time of starting the engine so that the catalytic reaction of the low-temperature exhaust gas passing through the honeycomb body is easily performed. .

As another example, as shown in FIG. 4, a large number of curved and flat bending members 32 extend radially from the central portion, and between two bending members, the wave height gradually increases from the central portion. The formed corrugated sheet materials 31 are joined together to form a cylindrical honeycomb body 30, and the outer peripheral electrodes are arranged at the same number and at equal intervals as the corrugated sheet materials on the outer peripheral surface of the honeycomb body intersecting the plane perpendicular to the axis. By applying a voltage between the center electrode 35 and one reverse center electrode 35 provided in the central portion, an electric current is caused to flow between the center electrode 35 and each outer peripheral electrode 36 on the outer circumference of the cylinder, and Joule heat is generated. There is disclosed a metal carrier for generating the heat and heating the entire honeycomb body.

[0008]

The above-mentioned conventional metal carrier for an electrically heated catalyst device shown in FIG. 3 is formed by stacking a plurality of flat plate materials and corrugated plate materials in a spiral shape to form a honeycomb body, and adjoining them. A bar-shaped support is disposed in the plurality of layers to provide insulation between the plurality of layers and to maintain the gap. When the conductor connection parts that are electrically connected to both ends of multiple layers of flat plate material and corrugated sheet material are connected to a power source (not shown) and a voltage is applied to heat, the multiple layers become parallel resistors, so the electrical resistance However, there is a drawback that a large current is consumed to heat the entire honeycomb body, and therefore there is a drawback that the conductive wire leading to the power source is burnt out.In addition, a method of holding a plurality of layers by a support to provide a gap is It has the drawback of being susceptible to vibration.

In addition, the metal carrier shown in FIG. 4 has a large number of bending members and corrugated plate members bonded between them, and also has a large number of outer peripheral electrodes arranged outside, which complicates the structure and reduces the manufacturing cost. It has the disadvantage of being expensive.

Further, since a brazing material of powder is used as the brazing material conventionally used for joining the flat sheet material and the corrugated sheet material, as shown in FIG. The distribution of the powdered brazing material 14 in 13 is not uniform. Therefore, the electric resistance values of the joints in the radial direction (X direction) are different, and it is difficult to flow the current uniformly and stably in the X direction. Therefore, the current flow direction is the Y ₁ direction passing through the corrugated sheet material 1. Also, there is a drawback that the metal carrier is heated by flowing in the Y ₂ direction passing through the flat plate material 2, and therefore, the roll-shaped layers must be electrically insulated.

An object of the present invention is to provide a metal carrier for an electric heating type catalytic device, which forms a honeycomb body formed by winding a flat plate material and a corrugated plate material in a roll shape, in which a stable current can be passed in a radial direction, and insulation is achieved. It is an object of the present invention to provide a metal carrier for an electrically heated catalyst device that forms a honeycomb body that does not use a structure, has a simple structure, is easily manufactured, and can be heated to a required temperature with a small current.

[0012]

MEANS FOR SOLVING THE PROBLEMS A metal carrier for an electrically heated catalyst device according to the present invention comprises a corrugated sheet material made of a thin metal plate in which corrugated irregularities are continuously bent and formed in a strip shape, and a flat strip shape. A thin plate made of a thin metal plate is joined by a brazing material at contact portions where they overlap and abut each other, and a honeycomb body wound in a roll shape and coaxially arranged so as to cover the outer periphery of the honeycomb body. In a metal carrier for a catalyst device having a honeycomb body and an outer cylinder joined by a brazing material, a long and narrow foil-shaped brazing material is used as the brazing material, and a single brazing material provided at the center of the honeycomb body is used. It has an electrode and a plurality of reverse electrodes arranged at equal intervals on the outer peripheral surface of the outer cylinder intersecting the plane perpendicular to the axis.

The above metal carrier for an electrically heated catalyst device has a structure in which one electrode arranged at the center of the honeycomb body and a plurality of electrodes arranged at equal intervals on the outer circumference of the outer cylinder. In order to set the electric resistance value of the electrode to a predetermined value, a plurality of electrodes are increased / decreased according to the outer diameter or the axial length of the metal carrier and are evenly arranged on the outer peripheral surface of the outer cylinder. Is preferably provided.

Further, an amorphous brazing filler metal is preferable as the elongated foil-shaped brazing filler metal used for joining the plate materials constituting the metal carrier for the electric heating type catalyst device and for joining the honeycomb body and the outer cylinder.

[0015]

[Function] Since the corrugated sheet material and the flat sheet material are overlapped and wound in a roll form to form a honeycomb body, and a thin foil-shaped brazing material is used at a joint portion, a radial direction joint is made in a cross section perpendicular to the axis of the honeycomb body. Since the electric resistance at the location becomes uniform, a voltage is applied between one electrode provided at the center of the honeycomb body and a plurality of electrodes provided at equal intervals on the outer circumference of the outer tube to form the honeycomb structure. The whole body can be heated evenly in the radial direction.

[0016]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a diagram of an embodiment of a metal carrier for an electrically heated catalyst device of the present invention, FIG. 1 (A) is a schematic perspective view, and FIG.
(B) is a schematic perspective view showing the arrangement of the plate material and the brazing material.

In FIG. 1A, the metal carrier 10 is
As shown in FIG. 1B, the corrugated plate material 1 and the flat plate material 2 are
The honeycomb body 9 is formed by stacking two thin foil-shaped brazing filler metals 3 on each other and winding them in a roll to form a cylindrical outer cylinder 4.
It is inserted in the inside and joined at the contact part.
The outer peripheral electrodes 6 are four electrodes provided at equal intervals on the outer surface including a cross section perpendicular to the axis of the outer cylinder 4, and one electrode provided at the center of the roll-shaped honeycomb body 9. A voltage can be applied to the center electrode 5.

By using the long and thin foil-shaped brazing filler metal 3 at the joint between the corrugated plate material 1 and the flat plate material 2, uniform and stable brazing can be performed, so that the electric resistance between the plate materials at each joint 13 is increased. The values become uniform and X shown in FIG.
A predetermined electric current can be passed in the direction, that is, the radial direction. Therefore, when a voltage is applied between the central electrode 5 and the four outer peripheral electrodes 6, four heating zones a, b, c, d are generated as shown in FIG. The metal carrier 10 forming the is heated uniformly in the cross section perpendicular to the axis.

To set the electric resistance value between the center electrode 5 and the outer peripheral electrodes 6 to a predetermined value corresponding to the outer diameter or the axial length of the metal carrier 10, the number of the outer peripheral electrodes 6 is increased or decreased. You can deal with it. It is preferable to use an amorphous brazing material for the elongated foil-shaped brazing material 3.

Further, although FIG. 1A shows the case where the outer peripheral electrode 6 is provided on one cross section perpendicular to the axis of the metal carrier 10, it is shown on a plurality of cross sections perpendicular to the axis of the metal carrier. A peripheral electrode can also be provided.

[0021]

As described above, according to the present invention, the corrugated plate material, the flat plate material, and the outer cylinder of the metal carrier forming the roll-shaped honeycomb body are bonded to each other using the elongated foil-shaped brazing material. Since the brazing between the plate materials at each joint is performed uniformly, the electric resistance in the radial direction becomes uniform, and the center electrode provided at the center of the metal carrier and the plurality of electrodes provided at equal intervals on the outer circumference of the outer cylinder. When a voltage is applied between the outer peripheral electrode and the outer peripheral electrode, the entire honeycomb body can be heated uniformly. Therefore, the insulating structure for forming the honeycomb body becomes unnecessary, and the structure is simplified, so that the electrically heated metal carrier can be easily manufactured by the conventional manufacturing method of the honeycomb body. The produced metal carrier has the effects of high durability and low cost. Furthermore, the metal carrier of the present invention is different from the conventional metal carrier in which the electric resistance value is changed depending on the thickness of the plate material or the number of layers, and the outer diameter and the axial length of the metal carrier change as well as the outer peripheral electrode. The electric resistance value of the metal carrier can be easily changed by changing the number.

[Brief description of drawings]

FIG. 1 is a view of a metal carrier for an electrically heated catalyst device of the present invention, FIG. 1 (A) is a schematic perspective view, and FIG. 1 (B) is a schematic perspective view showing an arrangement of a plate material and a brazing material.

FIG. 2 is an explanatory diagram showing a heating zone of a honeycomb body formed by electrodes.

FIG. 3 is a schematic cross-sectional view perpendicular to the axis of a conventional metal carrier for an electrically heated catalyst device.

FIG. 4 is a schematic cross-sectional view perpendicular to the axis of another conventional metal carrier for an electrically heated catalyst device according to the prior art.

[Fig. 5] Fig. 5 is a schematic partial cross-sectional view of a honeycomb body showing a state of a joint portion by a powder brazing material according to a conventional technique.

[Explanation of symbols]

1, 31 Corrugated plate material 2 Flat plate material 3 Brazing material 4, 56 Outer cylinder 5, 35 Center electrode 6, 36 Outer peripheral electrode 9, 30, 52 Honeycomb body 10 Metal carrier 13 Joining point 14 Powder brazing material 32 Curving material 53 Multiple layers 54 Gap 55 Electric Insulation Layer 57 Supports a, b, c, d Heat Generation Zones X, Y ₁ , Y ₂ Current Direction

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location F01N 3/28 301 Q

Claims (3)

[Claims] 1. A corrugated sheet material made of a strip-shaped thin metal plate in which corrugations are continuously bent and formed, and a flat sheet material made of a flat strip-shaped thin metal plate overlap and abut each other. A honeycomb body having a large number of mesh-like ventilation passages, which are joined by a brazing material at the contact portion and are wound into a roll, and coaxially arranged so as to cover the outer periphery of the honeycomb body. In a metal carrier for a catalyst device having a honeycomb body and an outer cylinder joined to the honeycomb body, an elongated foil-shaped brazing material is used as the brazing material, and one electrode arranged in the center of the honeycomb body, A metal carrier for an electrically heated catalyst device, comprising a plurality of electrodes arranged at equal intervals on an outer peripheral surface of the outer cylinder that intersects a plane perpendicular to the axis, and having a plurality of electrodes opposite to the electrodes. 2. A unit arranged at the center of the honeycomb body.
In order to set the electric resistance value between the individual electrodes and the plurality of electrodes arranged at equal intervals on the outer circumference of the outer cylinder to a predetermined value, the outer diameter or the axial length of the metal carrier is set. The metal carrier for an electrically heated catalyst device according to claim 1, wherein the metal carrier for an electrically heated catalyst device has a plurality of electrodes that are increased / decreased according to the height and are arranged at equal intervals on the outer peripheral surface of the outer cylinder. 3. The metal carrier for an electrically heated catalyst device according to claim 1, wherein an amorphous brazing material is used as the brazing material.