JPH081011A - Self-heating type catalyst convertor - Google Patents

Abstract

PURPOSE:To obtain both of high resistance and low heat capacity of a honeycomb carrier, to activate the catalyst with small electric power in a short time, and to improve its durability. CONSTITUTION:This catalyst convertor is a self-heating type one to be disposed in the route of exhaust gas from an engine. The honeycomb carrier which carries the catalyst material consists of flat plates and wavy plates of metal foils. Slits 2a, 3a as a mesh-like aperture are formed in at least a part of these plates. The honeycomb body is provided with electrodes 12 (12a, 12c), 22 (22a, 22c) which enable application of an electric current on the slit part in the axial direction of the honeycomb body. These electrodes are joined with rings 8, 9 attached around the honeycomb body. A part of the electrode is formed as a rod electrode 12a which projects outside through an engaging hole of an outer cylinder 13 and fixed to the outer cylinder 13 with insulating members 14a, 14b and gasket members 15a, 15b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a catalytic converter as an exhaust gas purifying device for automobiles, and more particularly to self-heating the catalyst carrier itself to generate heat in order to accelerate activation of a substance that performs a catalytic action. Type catalytic converter.

[0002]

2. Description of the Related Art Conventionally, for example, a catalytic converter is interposed in an exhaust path of an automobile engine to convert harmful components such as CO, HC and NOx contained in exhaust gas into harmless gas or water. Has been done. However, when only the catalytic converter is used, there is a problem that the exhaust gas is hard to be purified because the catalytic substance is not activated when the temperature of the exhaust gas is low at the initial stage of engine startup.

Therefore, in JP-A-2-223622 and JP-A-5-277379, a self-heating honeycomb filter is separately supported on a honeycomb carrier of a catalytic converter on which the catalyst is carried, and a self-heating honeycomb filter is supported on the honeycomb carrier. It has been proposed to provide a catalytic converter composed of a heat-generating honeycomb carrier to electrically heat the self-heat-generating honeycomb carrier to activate the catalyst substance.

In these self-heating type honeycomb carriers, corrugated metal plates in the form of strips formed by continuously bending corrugations and flat metal plates in the form of flat strips are alternately stacked. It is formed by winding or laminating.

When heating these catalytic converters, an electrode is provided at the center and the outer peripheral surface to allow a current to flow from the central portion toward the outer surface, or one on each of the opposing outer peripheral surfaces, a total of two. A self-heating type honeycomb carrier has been proposed in which an electrode is provided and an electric current is passed across a radial cross section of the honeycomb carrier to generate heat.

Further, in joining between these honeycomb carriers made of metal and the outer peripheral ring supporting the honeycomb carriers, in JP-A-5-253493, the outer layer on the same radial cross section as the joining portion between the honeycomb carrier and the ring is disclosed. There has been proposed a method of providing a bonded portion of the honeycomb carrier itself in the portion.

[0007]

However, in such a self-heating type honeycomb carrier, it is necessary to give a predetermined resistance value to the corrugated plate and the flat plate in order to generate heat by heating the carrier itself by heating. In the case of a self-heating type honeycomb carrier in which a current is passed from the center electrode toward the outer surface as in the prior art, the length of the strip-shaped corrugated sheet material and the flat sheet material is made sufficiently long to secure the resistance value. There is a need.

In the conventional honeycomb carrier, it is necessary to make the length of the metal foil very long for the above-mentioned reason.
As a result of the increase in the heat capacity of the honeycomb carrier itself, the rate of temperature rise during energization becomes extremely slow, and the temperature does not rise rapidly unless a large current is applied.Therefore, the catalyst is sufficiently activated immediately after the engine is started and high purification performance is achieved. Hard to get.

Further, in order for the catalytic converter to have sufficient strength against engine vibration, the contact portions between the corrugated plate material and the flat plate material of the honeycomb carrier must be mechanically joined by a method such as welding. Although desirable, it is very difficult to join while maintaining electrical insulation. In particular, when a current is passed from the center electrode toward the outer surface, if the end surfaces are joined by welding, the required resistance value cannot be obtained at all. For this reason, since it is not possible to simply weld the end faces of the honeycomb carrier, it is extremely difficult to electrically maintain insulation while maintaining sufficient strength.

Further, in the conventional catalytic converter, the heat generated by the metal foil forming the corrugated plate and the flat plate when the self-heating honeycomb carrier is heated to increase the temperature inside the honeycomb carrier by heat conduction. Since it spreads, there is a problem that it takes a very long time to raise the temperature of the catalyst to the activation temperature. Further, there is a problem that the honeycomb carrier is damaged due to thermal stress and vibration during repeated heating and cooling cold and heat cycles.

As described above, it is extremely difficult to satisfy all the conditions of securing the resistance value of the honeycomb carrier and reducing the heat capacity and improving the durability. In view of such problems of the conventional technology, the present invention makes both high resistance and low heat capacity of the honeycomb carrier compatible with each other, reduces heat conduction, improves durability, and quickly and sufficiently with a small amount of electric power. It is an object of the present invention to obtain a self-heating type catalytic converter capable of raising the temperature of a honeycomb carrier to any temperature.

[0012]

In order to achieve this object, the present invention is directed to a self-heating metal catalytic converter arranged in an exhaust path of an engine, wherein a honeycomb carrier carrying a catalytic substance is made of metal. Of the flat plate and the corrugated plate, at least a part of the flat plate and / or the corrugated plate is provided with a slit as an opening, and the flat plate and the corrugated plate are alternately laminated and / or wound. A part of the layers formed by turning is joined, and a current inflow / outflow portion is provided to allow a current to flow in the axial direction of the honeycomb carrier with respect to the slit portion of the flat plate and / or the corrugated plate. The current inflow / outflow portion has a rod-shaped electrode that is joined to a ring that is joined around the honeycomb carrier and that protrudes to the outside through the mounting hole of the outer cylinder, and the rod-shaped electrode is opposed to the outer cylinder. It is intended to provide a self-heating type catalytic converter, characterized in that fixed through the insulating member and the gasket member Te.

[0013]

According to the present invention, since the flat plate or the corrugated plate forming the honeycomb carrier is provided with the slit portion, it is possible to obtain the flat plate or the corrugated plate having a higher electric resistance than the conventional one. Therefore, unlike the conventional case, a long material is not required for the flat plate or the corrugated plate, so that the heat capacity of the honeycomb carrier becomes extremely small, and it is possible to raise the temperature up to the activation temperature of the catalyst within a short time even with low power. .

Further, since the heat conduction in the axial direction can be extremely reduced by the slit portion provided on the flat plate or the corrugated plate, the heat at the time of temperature rise is accumulated in the catalytic converter,
The temperature rising rate can be increased. Therefore, the input power can be small due to this heat storage effect.

Further, the joint portion inside the honeycomb carrier, the joint portion between the ring and the honeycomb carrier, and the joint portion between each electrode and the ring and the honeycomb carrier, or the joint portion inside the honeycomb carrier have the same diameter of the honeycomb carrier. By avoiding providing in the direction cross section, and by displacing them in the direction of the central axis, it is possible to prevent the heat of the electrode and the ring from directly flowing into the joint portion of the honeycomb carrier, and the same as the joint portion of the honeycomb carrier. The temperature gradient in the radial cross section can be reduced.
Therefore, the thermal stress generated in the honeycomb carrier is extremely small.

Further, when the number of electrodes supporting the honeycomb carrier is three or more, radial vibration can be suppressed. Further, by dividing the outer cylinder containing the honeycomb carrier into the same number as the number of + and / or-electrodes,
The outer cylinder member can be easily inserted from the axial direction of the electrode, and it is possible to prevent unreasonable stress from acting on the honeycomb carrier during assembly.

[0017]

By carrying out the present invention, a self-heating type that is extremely durable and can activate the catalyst by raising the temperature in a short time with a small amount of electric power to obtain high purification performance. It is possible to provide a catalytic converter.

[0018]

The first embodiment of the present invention will be described in detail below.
FIG. 1 is a perspective view of a self-heating honeycomb carrier in which a catalyst is supported on a self-heating honeycomb filter. The self-heating type honeycomb carrier 1 of the first embodiment has a flat plate 2 and a corrugated plate in which slits are formed in a portion excluding a downstream end 1a which is a current inflow portion and an upstream end 1b which is a current outflow portion. 3 and 3 are overlapped and rolled up in a spiral shape. A power source 4 and a switch 5 are connected to the downstream end 1a of the self-heating honeycomb carrier 1 so that electricity can be conducted between the upstream end 1b and the downstream end 1a. The upstream end 1b is grounded.

FIG. 2 is a development view showing in detail the shape of the flat plate slit portion 2a formed on the flat plate 2 used in the honeycomb carrier 1 of the first embodiment. In the flat plate slit portion 2a of the first embodiment, the length in the spiral direction is b, and the length in the axial direction is d.
Is formed in a positional relationship that is shifted in the spiral direction by half (b + c) / 2 of the spiral direction pitch (b + c). It is provided at a portion of width g between 1b and the downstream end 1a of width h. In addition, as for the material of the flat plate 2, Cr is 18 to 2
4% by weight, 4.5 to 5.5% by weight of Al, 0.01 to 0.2% by weight of rare earth metal (REM), the balance being Fe-Cr-Al composition consisting of Fe, and its plate thickness is t
= 0.03 to 0.05.

Further, the corrugated plate 3 also has a corrugated plate slit portion 3 having the same shape as the flat plate slit portion 2a formed on the flat plate 2.
a is formed, and unevenness is continuously formed.
Flat slit part 2a or corrugated plate slit part 3
Since a has many openings, that part looks like a mesh.

Next, a method of manufacturing the self-heating converter of the embodiment will be described with reference to FIG. First, as shown in FIG. 3, the honeycomb carrier 1 of the first embodiment is superposed so that the corrugated plate slit portions 3a of the corrugated plate 3 face the flat plate slit portions 2a formed on the flat plate 2. Then, the end portion is sandwiched by a pair of semi-cylindrical winding jigs 7a and 7b. Then, the winding jigs 7a and 7b are wound to a predetermined size, and when the predetermined size is reached, the winding jigs 7a and 7b are removed. After that, after being further wound to a predetermined size, the flat plate 2 and the corrugated plate 3 are welded and joined by laser welding so that the contact portions on both end faces of the flat plate 2 and the corrugated plate 3 are electrically short-circuited. .

Then, this structure is set at 800 ° C. to 1200 ° C.
Heat for 1 to 10 hours to deposit Al oxide on the metal surface.
Then, the entire surface of the contact portion between the flat plate 2 and the corrugated plate 3 is oxidized with Al.
Joined by objects. And this structure is γ-Al₂
O₃It is impregnated into a slurry containing
Perform the washcoat process. Then a catalytic metal, for example
Impregnate into an aqueous solution of Pt and Ph and sinter again
You. As a result, γ-Al ₂O₃And the catalytic substance adhere to
The self-heating type honeycomb carrier 1 can be obtained. like this
The honeycomb carrier 1 manufactured as described above is housed in a casing.
Mounted in the exhaust path of the car by this casing
Is done.

To describe the first embodiment in more detail, the self-heating honeycomb carrier 1 has dimensions of 66 mm in diameter and 67 mm in length. Further, the flat plate slit portion 2a of the flat plate 2 and the corrugated plate slit portion 3a of the corrugated plate 3 have substantially the same shape, and the size of each portion shown in FIG. 2 is f = 11 mm, h
= 27.65 mm, g = 28.35 mm, e = 0.35
mm, b = 45 mm, and c = 5 mm.

In this way, a plate thickness of 0.05 made of Fe-Cr-Al-REM having the slit shape with the above-mentioned dimensions is obtained.
mm flat plate 2 and this flat plate 2 having a wave height of 1.45 mm,
A corrugated sheet 3 processed into a corrugated sheet material having a wave pitch of 4.75 mm is obtained. Then, the flat plate 2 and the corrugated plate 3 are superposed on each other and wound in a circular shape. FIG. 4 shows a configuration in which this self-heating honeycomb carrier 1 is housed in a casing and attached in the exhaust path.
Shown in

As shown in FIG. 4, an upstream ring 8 and a downstream ring 9 made of stainless steel are joined to the upstream end 1b and the downstream end 1a by laser welding. A flange 11 for attaching to the exhaust manifold 10 is joined to the upstream ring 8 by welding. Further, as is apparent from FIG. 5 showing the cross section AA of FIG. 4, stainless steel support rods 12 (12a, 12b, 12c) are attached to the downstream ring 9.

The support rod 12 includes ceramic gaskets 14a and 14 for maintaining electrical insulation from the outer cylinder 13, gaskets 15a and 15b made of copper, and a nut 16 screwed to the support rod 12. It is fixed airtightly using. Immediately downstream of the self-heating honeycomb carrier 1, a capacity 1300 cc supported by a wire net 18 in a case 17 having an oval cross section.
The main monolith catalyst 19 made of ceramic is held.

In the first embodiment, when the slit shape as shown in FIG. 2 is provided, one foil portion b × e left by forming the slit has a resistance value of about 1.7Ω. Thus, the whole equivalent circuit is as shown in FIG. That is, each of the resistors in FIG. 6 has a resistance of about 1.7Ω, and a high resistance of about 0.3Ω can be realized as a whole.

In the self-heating type honeycomb carrier 1 having the above-described structure, about 30 to 12 V is applied immediately after the engine is started.
When the electric power of 40 A was supplied, the self-heating honeycomb carrier 1 was 400 times in about 8 seconds (the engine was idling).
C. to 500.degree. C. are heated, which activates the catalytic material and purifies the exhaust gas emitted from the engine.

As described above, in the self-heating type honeycomb carrier 1 of the first embodiment, the slits are provided in the flat plate 2 and the corrugated plate 3 so that the height can be easily increased between the upstream end 1b and the downstream end 1a. Since a resistor can be formed and it is not necessary to take a long metal foil to secure a resistance value as in the conventional case, a honeycomb carrier having an extremely low heat capacity can be realized. Therefore, it is possible to raise the temperature in a short time with a low electric power, and the catalyst substance can be rapidly activated.

Further, the slits formed on the flat plate 2 and the corrugated plate 3 are displaced in the axial direction of the self-heating honeycomb carrier 1 by alternating the positions of the slit intervals by approximately half the length of the slits. Therefore, the heat conduction can be made extremely small as compared with the conventional self-heating type honeycomb carrier having no slit.

For example, in the slit size used in the case of FIG. 2, the ratio is about 2.6 × 10 ⁻⁴ times, and the heat generated when the temperature is increased by energizing is stored in the self-heating honeycomb carrier 1. It is easy to be done. Therefore, a portion where the catalytic substance reaches the activation temperature is generated early after the start of the temperature rise, and the other portion is activated by receiving the heat of the catalytic reaction from this portion, so that the input electric power is also small.

Further, since the heat conduction in the axial direction becomes extremely small due to the slits formed in the flat plate 2 and the corrugated plate 3, the heat generated when the current is supplied and heated is easily accumulated in the self-heating honeycomb carrier 1. Has become. Therefore, after the temperature rise is started, there is a place where the activation temperature of the catalytic substance is reached within a short time as compared with the conventional self-heating type honeycomb carrier, and the whole of the catalyst quickly receives the heat of the catalytic reaction started from this part. It will be activated by raising the temperature. In other words, the input power can be small due to this heat storage effect.

Furthermore, since the contact portion between the corrugated plate 3 and the flat plate 2 can be completely welded, a self-heating type honeycomb carrier which is extremely strong against heat load and engine vibration and has excellent durability is realized. be able to. In addition, as another embodiment of the present invention, a self-heating honeycomb carrier is
Instead of winding up as in the embodiment, as shown in FIG. 7, the converter 21 may be formed by alternately stacking the flat plate 2 and the corrugated plate 3 in a substantially flat state.

In the examples shown in FIGS. 4 and 5, the self-heating honeycomb carrier is mounted very close to the exhaust manifold so that the temperature of the self-heating honeycomb carrier can be raised early by receiving the exhaust gas temperature. It can be said that such a place is in a very severe environment because it is exposed to high temperature exhaust gas and engine vibration while the vehicle is running. However, since the corrugated plate and the flat plate of the self-heating honeycomb carrier 1 are mechanically welded and joined to each other, and the flat plate and the corrugated plate are joined to each other by the oxide of Al by the oxidation heat treatment step. , It is extremely strong against heat load and engine vibration and does not cause any problem in durability.

In the first embodiment, not only the self-heating type honeycomb filter is made to support the catalyst to form the self-heating type honeycomb carrier, but also the flat plate and corrugated plate forming the carrier are provided with slits. The point is characteristic. However, it is possible to configure a small self-heating type catalytic converter that can obtain sufficient heat generation even when slits are provided in the flat plate and the corrugated plate that constitute the self-heating type honeycomb filter where the catalyst is not supported. it can.

Next, the bonding area between the flat plate and the corrugated plate and the bonding area between the honeycomb carrier and the outer peripheral ring in the honeycomb carrier will be described in detail. FIG. 8 shows a cross-sectional view of the honeycomb carrier of the first embodiment and the portion accompanying it. FIG.
Is a first member that is selectively bonded inside the honeycomb carrier 1 by using a method such as brazing, laser welding, or discharge welding.
Area 23, second area 24, third area 25, fourth area 26
Are shown as thick shaded areas, and
First bonding between the honeycomb carrier and the ring selectively by using a technique such as brazing, laser welding, or discharge welding
The area 31 and the second area 32 are shown as areas with thin diagonal lines.

As shown in FIG. 8, the joint portions 23 to 26 of the honeycomb carrier and the joint portion 3 between the ring and the honeycomb carrier 3 are joined together.
Nos. 1 and 32 are not in the same radial cross section of the honeycomb carrier, and are shifted by mb at the upstream end 1b and by ma at the downstream end 1a in the central axis direction. Specifically, in the first embodiment, mb = 2 mm, ma = 15 m
It has become m. Therefore, the heat of the ring does not directly flow into the joint portions 23 to 26 of the honeycomb carrier, and the distances mb, ma
You just have to detour. Therefore, the temperature gradient inside the honeycomb carrier having the same radial cross section as the joined portion of the honeycomb carrier is small, and the thermal stress generated in the honeycomb carrier can be made extremely small. Moreover, these welding intervals m
By suppressing b and ma to be 30 mm or less, it is possible to suppress the thermal stress in the axial direction that acts on the honeycomb carrier joints 23 to 26.

Further, the honeycomb carrier joints 23 to 26 are formed.
Are provided on 50% or more of the contact portions 33 of the flat plate and the corrugated plate in the same radial cross section of the honeycomb carrier shown in FIG. Therefore, the radial deformation of the cells inside the honeycomb carrier is restricted, and the Young's modulus in the radial direction increases,
It has a strong structure against the radial vibration of the honeycomb carrier.

Further, the mesh-shaped slit portions 2a, 3
At least one bonded portion of the honeycomb carrier is provided in a range of 1 mm or more and 10 mm or less from both ends k1 and k2 of a. Therefore, vibration of the honeycomb carrier at both ends of the mesh-shaped portion is suppressed, and a large gap is formed at the boundary between the mesh-shaped slit portions 2a and 3a and the upstream end 1b and the downstream end 1a in which the configuration of the honeycomb carrier changes. Prevents stress.

Further, the joint portions provided in the same radial cross section of the honeycomb carrier are provided at two or more locations different in the central axis direction. In the first embodiment, the upstream end 1b,
The downstream end 1a is provided at two places each, and the intervals between the joints are nb = 6 mm at the upstream end 1b and na = 3 mm at the downstream end 1a. for that reason,
The axial deformation of the cells inside the honeycomb carrier is restrained to increase the axial Young's modulus, and the structure has a strong structure against the axial vibration of the honeycomb carrier.

Further, as shown in FIG. 10, the joint portions 31 and 32 between the ring and the honeycomb carrier are provided partially on an arbitrary cross section that crosses the honeycomb carrier and the ring. By providing the joining portion on an arbitrary certain cross section, automation of the joining process is facilitated, and by partially providing the joining portion, thermal stress in the circumferential direction between the ring and the honeycomb carrier is relaxed. Also, to prevent the joint from meandering,
It is possible to facilitate the positioning of the joint between the flat plate and the corrugated plate of the honeycomb carrier and the joint between the ring and the honeycomb carrier, and also to facilitate the automation of the bonding process.

Further, the joint portions 31 and 32 between the ring and the honeycomb carrier 31b1 and 31b are located at different positions in the central axis direction at the upstream end portion 1b and the downstream end portion 1a, respectively.
2, 32a1 and 32a2 are provided so as to be on the same radial cross section. At the time of energizing the honeycomb carrier, the current flows in the order of the + electrode 12 (support rod), the downstream ring 9, the rear plate joint 32, the honeycomb carrier 1, the front plate joint 31, the upstream ring 8, and the-electrode 22, By providing a joint between the ring and the honeycomb carrier at two different locations in the central axis direction to increase the joint area, the joints 31, 32
The current flowing through the cells is dispersed to prevent the temperature of the honeycomb carrier at the joint from rising abnormally. Further, by increasing the bonding area between the ring and the honeycomb carrier, the stress generated between the ring and the honeycomb carrier is also reduced. Furthermore,
By providing each joint on the same radial cross section, automation of the joining work is facilitated.

Next, the bonding area of the electrodes will be described in detail. As shown in FIG. 8, the electrode 22, the electrode (supporting rod) 12, and the joint portions 31 and 3 between the ring and the honeycomb carrier.
2 is not in the same radial cross section of the honeycomb carrier, and is pb at the upstream end 1b and pa at the downstream end 1a in the central axis direction.
It is just staggered. In the first embodiment, specifically, pb = 1 mm and pa = 6 mm. For this reason, the heat of the electrodes does not flow directly into the joint portions 23 to 26 of the honeycomb carrier, and must be detoured by the intervals pb + mb and pa + ma. Therefore, the temperature gradient in the honeycomb carrier in the same radial cross section as the honeycomb carrier joint portion is small, and the thermal stress generated in the honeycomb carrier can be made extremely small.

Further, it is desirable that the position of the electrode is not provided in the same radial cross section as the joint portion of the honeycomb carrier, but is displaced in the central axis direction. In the first embodiment, specifically, the downstream end 1a is displaced by qa = 2 mm. Accordingly, it is possible to prevent the heat of the downstream ring 9 around the bonded portions 25 and 26 of the honeycomb carrier from being maintained when the honeycomb carrier is cooled, and suppress the thermal stress of the bonded portion of the honeycomb carrier.

Further, as shown in FIG. 11, the ring-honeycomb carrier joint 31 is not provided on the radial straight line r connecting the center point O of the honeycomb carrier and the electrode 22 at the upstream end 1b. . The same applies to the downstream end 1a. As a result, the upstream ring 8 and the downstream ring 9 around the electrodes 22 and 12 which become hot when the honeycomb carrier is cooled do not have a ring-honeycomb carrier joint.
It is very advantageous in terms of durability.

Next, the support of the honeycomb carrier by the electrodes will be described in detail. As shown in FIG. 4 and FIG. 5, the honeycomb carrier 1 has three electrodes 12a, 12b, 12c, 22a, and
It is supported by 22b and 22c. Moreover, the electrodes provided on each ring are evenly arranged in the circumferential direction.

As shown in Japanese Patent Laid-Open No. 5-277379, when a honeycomb carrier is supported by two electrodes, the position of the honeycomb carrier with respect to the outer cylinder is not uniquely determined, which is difficult to manufacture. was there. However, as shown in FIG. 5, three or more electrodes (support rods) 12a, 1
When the honeycomb carrier 1 is supported by 2b and 12c, the position of the honeycomb carrier 1 is uniquely determined, which facilitates manufacturing. In addition, a vibration resistance effect that suppresses radial vibration is also produced thereby.
Furthermore, by arranging the electrodes evenly in the circumferential direction,
It is possible to evenly disperse the thermal stress in the radial direction and prevent the honeycomb carrier from being deformed. Further, by making the number of the electrodes odd, the electrodes do not exist at the positions facing each other, so that the radial deformation of the honeycomb carrier is not constrained, and the thermal stress in the radial direction can be reduced.

Further, one of the support rods 12 for the + electrode 12
The length a is longer than the support rods 12b and 12c for the other electrodes. Therefore, it is easy to take out the wiring for energization from the support rod 12a of the + electrode, and the structure of the connector portion of the electrode portion and the wiring portion is simplified. Needless to say, the same applies when one of the electrode bolts is made longer than the other electrode bolts.

Furthermore, the bolt (-electrode bolt) 22 for the electrode on the side electrically grounded to the outer cylinder and the flange is the bolt (+ electrode bolt) 12 which is the support rod on the side not grounded.
Is thinner than. Further, the electrode bolt is grounded to the outer cylinder and the flange on the upstream side. in this way,
By reducing the diameter of the grounding side electrode, in which the current is distributed to the three electrodes and the current density per one is low, the heat capacity is reduced and the heat dissipation path from the honeycomb carrier is narrowed to further reduce power consumption. It also enables early temperature rise.
The exhaust heat can be effectively used by configuring the electrode on the upstream side of the honeycomb carrier as described above.

Next, the outer cylinder for housing the honeycomb carrier will be described in detail. As shown in FIG. 12, the outer cylinder 13 for accommodating the honeycomb carrier is divided into the same number as the number of + and-electrodes, and is evenly divided in the circumferential direction. Each of the outer cylinder members has + and-electrodes. Holes for passing through (33a, 33b)
Are provided in each case. Therefore, the same outer cylinder members 13a, 13b, 13c can be easily inserted in the axial direction of the electrodes, and no unreasonable force acts on the honeycomb carrier during assembly. Moreover, since the honeycomb carrier 1 can be easily positioned by the holes provided in the outer cylinder, the assembling property is good.

Further, holes (33
a, 33b) are formed so as to avoid the dividing lines 34 to 36 of the outer cylinder. Therefore, welding between outer cylinder members and electrode-
The outer tubular members can be welded independently, and the outer tubular members can be welded first to prevent deformation of the honeycomb carrier during welding. Furthermore, the + and-electrodes 12 and 22 and the two holes (3
3a, 33b) are arranged on substantially the same line in the direction of the outer cylinder center axis, and positioning is easy at the time of assembly.

As described above, the honeycomb carrier 1 in the first embodiment has both heat fatigue resistance and vibration resistance against thermal stress, and it is possible to obtain a high purification rate as a self-heating type catalytic converter.

Next, the process of manufacturing the honeycomb carrier of the first embodiment, particularly the welding method, will be described in detail with reference to FIG. Strip-shaped flat plate 72 that has been cut to a predetermined size
One of the two stainless foils wound in a roll shape is guided to the corrugated plate forming gears 77a and 77b to form the corrugated plate 73. Then, the formed corrugated plate 73 is used as the other flat plate 7
Roll it on top of 2.

Further, without stopping the winding process while performing this winding, one of the two peaks 78 of the corrugated plate 73 is formed from two directions on a diagonal line in a cross section perpendicular to the axial direction of the honeycomb carrier.
On the other hand, the valley portion 79 of the corrugated plate is joined to the adjacent flat plate 72 by the laser emitted from the YAG laser head.
The position of this laser welding needs to be detected because it needs to be performed at the contact portion between the flat plate 72 and the corrugated plate 73. Therefore, the laser displacement sensor 81 and the eddy current displacement sensor 82 are provided in this manufacturing apparatus. Then, the position is detected, the laser focal length is corrected, and the winding process is performed simultaneously with the winding process without stopping the winding process.

That is, the laser displacement sensor 81 detects a gap between the laser head 80 and the metal honeycomb carrier 71, and sends a signal to a servo motor (not shown) for moving the laser head 80. In addition, the eddy current displacement sensor 8
1 detects the peak 78 or the valley 79 of the corrugated plate 73,
The YAG laser is emitted based on the detection signal. By the above control, the flat plate 72 and the corrugated plate 73 can be accurately laser-welded.

FIG. 14 is an explanatory view showing the vicinity of the portion where laser welding is performed. That is, FIG. 14 shows a case where laser bonding is performed at four points in the axial direction. In this case, the YAG laser is divided into four by the half mirror 83 in order to enable four-point bonding. Then, each of the divided parts is irradiated through the fiber cable 84 and the laser head 80 to the joining portion.

The other steps in the manufacturing method, such as the method of supporting the catalyst on the honeycomb carrier 71, are carried out by the same method as the above-mentioned example. Reference numeral 76 in the drawing denotes a mesh portion, that is, a slit portion formed in a part of the flat plate 72 and the corrugated plate 73. By dividing the laser light as described above,
The number of joining points can be easily increased in the axial direction.

Next, a second embodiment of the present invention will be described. This embodiment is characterized in that the honeycomb carrier has a bonding position different from that of the first embodiment. That is, in the first embodiment, the self-heating type catalytic converter in which the respective joints of the honeycomb carrier provided in the same radial cross section of the honeycomb carrier are located on the upstream side of the joint between the ring and the honeycomb carrier will be described. However, the second embodiment is a self-heating type catalytic converter in which a joint between the ring and the honeycomb carrier is provided at an intermediate position of the joint between the adjacent honeycomb carriers provided in the same radial cross section. This point will be described in detail with reference to FIGS. 15 and 16.

FIG. 15 is a sectional view of the honeycomb carrier of the second embodiment and the portion accompanying it. In the second embodiment, the welding position of the rear plate 41a of the honeycomb carrier 41 is different from that in the first embodiment. FIG. 15 shows a third region 45 and a fourth region 46, which are selectively joined by using a technique such as brazing, laser welding, and discharge welding inside the honeycomb carrier 41, respectively, and a third region 45 and a fourth region 46, which are indicated by thick diagonal lines, and the honeycomb carrier. The second, shown by the thin diagonal lines, selectively joined between the rings using techniques such as brazing, laser welding or discharge welding.
A region 47 is shown.

As shown in FIG. 15, the joint portions 45 and 46 of the honeycomb carrier and the joint portion 47 between the ring and the honeycomb carrier are not on the same radial cross section of the honeycomb carrier, but are on the downstream side in the central axis direction. The end portion 41a is displaced by ma. Specifically, ma = 10 mm in the second embodiment. Therefore, the heat of the ring 49 does not directly flow into the joint portions 45 and 46 of the honeycomb carrier, but the heat bypasses the gap ma and flows. Therefore, the temperature gradient in the honeycomb carrier in the same radial cross section as the joined portion of the honeycomb carrier becomes small, and the thermal stress generated in the honeycomb carrier can be made extremely small. Moreover, by suppressing the welding distance ma to 30 mm or less, it is possible to suppress the axial thermal stress acting on the joint portions 45 and 46 of the honeycomb carrier.

Furthermore, the joint portions 45, 4 of the respective honeycomb carriers are
6 is provided in 50% or more of the contact portion 33 between the flat plate and the corrugated plate in the same radial cross section of the honeycomb carrier as shown in FIG. Therefore, the radial deformation of the cells in the honeycomb carrier is restricted, the Young's modulus in the radial direction increases, and the honeycomb carrier has a strong structure against vibration in the radial direction.

Further, the joints formed in the same radial cross section in the honeycomb carrier are provided at two or more locations different in the central axis direction. Also in the second embodiment, the downstream end portion 41a is provided at two places, and the distance between the joint portions is na =
It is 23 mm. Therefore, the axial deformation of the cells in the honeycomb carrier is restricted, the Young's modulus in the axial direction increases, and the honeycomb carrier has a strong structure against vibration in the axial direction.

Further, as shown in FIG. 16, the joint 47 between the ring and the honeycomb carrier is provided on an arbitrary cross section that crosses the honeycomb carrier and the ring, and is partially provided.
The joining process is facilitated by providing the joining unit on any given cross section, and the partial provision of the joining unit reduces the thermal stress in the circumferential direction between the ring and the honeycomb carrier.

Further, the joint portion 47 between the ring and the honeycomb carrier is provided on the same cross-section, such as 47a1 and 47a2, at two locations on the downstream side end portion 41a, each of which has a different position in the central axis direction. When the honeycomb carrier is energized, the current is positive electrode 42, downstream ring 4
9, the joint portion 47 at the downstream end, the honeycomb carrier 41, the joint portion at the upstream end, the upstream ring, and the electrode flow in this order, but the joint portion between the ring and the honeycomb carrier is different in the central axis direction. By providing the bonding area at the location to increase the bonding area, the current flowing through the bonding portion 47 is prevented from being dispersed and the temperature of the honeycomb carrier at the bonding portion is prevented from abnormally rising. Further, by increasing the bonding area between the ring and the honeycomb carrier, the stress generated between the ring and the honeycomb carrier is also reduced. Further, the joining process is facilitated by providing each joining portion in the same radial cross section.

Next, the electrode bonding area will be described in detail. As shown in FIG. 15, the + electrode 42 and the joint 47 between the ring and the honeycomb carrier are not in the same radial cross section of the honeycomb carrier, and are displaced by pa in the central axis direction at the downstream end 41a. Specifically, in the second embodiment, pa = 2 mm. Therefore, the heat of the + electrode does not directly flow into the joining portions 45 and 46 of the honeycomb carrier, but the heat flows by bypassing the interval pa + ma.
As a result, the temperature gradient in the honeycomb carrier having the same radial cross section as the joined portion of the honeycomb carrier becomes small, and the thermal stress generated in the honeycomb carrier can be made extremely small.

Further, it is desirable that the electrodes are not provided in the same radial cross section as the joint portion of the honeycomb carrier, but are displaced in the central axis direction. In the second embodiment, the end 41a on the downstream side is displaced by qa = 2 mm. This prevents heat from being maintained in the downstream ring 49 around the joints 45, 46 of the honeycomb carrier during cooling of the honeycomb carrier, and suppresses thermal stress generated in the joints of the honeycomb carrier.

Further, similarly to the first embodiment shown in FIG. 11, the downstream end 41a of the second embodiment also has a radial straight line connecting the center point of the honeycomb carrier and the electrode 42. No ring-to-honeycomb carrier joint 47 is provided. As a result, no joint between the ring and the honeycomb carrier is provided in the downstream ring 49 around the electrode 42, which becomes hot when the honeycomb carrier is cooled, which is extremely advantageous in terms of durability.

In addition, also in the second embodiment, for example,
The supporting of the honeycomb carrier by the electrodes, the outer cylinder for housing the honeycomb carrier, the welding method of the inside of the honeycomb carrier, and the like are the same as in the first embodiment. As described above, also in the second embodiment, the honeycomb carrier has both thermal fatigue resistance and vibration resistance against thermal stress, and it is possible to obtain a high purification rate as a self-heating type catalytic converter.

[Brief description of drawings]

FIG. 1 is a perspective view of a self-heating type catalyst carrier according to a first embodiment.

FIG. 2 is a development view of a flat plate according to the first embodiment.

FIG. 3 is a perspective view showing a joined state of a flat plate and a corrugated plate.

FIG. 4 is a cross-sectional view of the self-heating catalytic converter of the first embodiment arranged in the exhaust path of the engine.

5 is a cross-sectional view taken along the line AA of FIG.

FIG. 6 is an equivalent circuit diagram of the honeycomb carrier of the first embodiment.

FIG. 7 is a perspective view showing a modification of the first embodiment.

[Fig. 8] Fig. 8 is a perspective view showing a bonded state of the honeycomb carrier, the outer peripheral ring, and the electrodes in the first embodiment by cutting them.

FIG. 9 is an enlarged sectional view showing a contact portion between a flat plate and a corrugated plate.

FIG. 10 is a perspective view showing a bonded state of the honeycomb carrier, the outer peripheral ring, and the electrodes in the first embodiment.

FIG. 11 is a radial cross-sectional view showing a bonded state of the honeycomb carrier, the outer peripheral ring, and the electrodes in the first embodiment.

FIG. 12 is a perspective view illustrating a structure of an outer cylinder portion in the first embodiment.

FIG. 13 is a conceptual diagram of an apparatus for manufacturing the carrier of the first embodiment.

FIG. 14 is a perspective view of an apparatus for joining carriers according to the first embodiment.

[Fig. 15] Fig. 15 is a perspective view showing a joined state of a honeycomb carrier, an outer peripheral ring, and electrodes in a second embodiment in a cut state.

FIG. 16 is a perspective view showing a bonded state of the honeycomb carrier, the outer peripheral ring, and the electrodes in the second embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Self-heating type honeycomb carrier (1st Example) 1a ... Downstream end 1b ... Upstream end 2 ... Flat plate 2a ... Flat plate slit 3 ... Corrugated plate 3a ... Corrugated plate slit 6 ... Opening 7a, 7b ... Winding jig 8 ... Upstream side ring 9 ... Downstream side ring 12 (12a to 12c) ... Support rod (electrode member) 13 ... Outer cylinder 13a to 13c ... Outer cylinder member 14a, 14b ... Ceramic gasket 15a, 15b ... Gasket 16 ... Nut 19 ... Ceramic monolith catalyst 21 ... Converter (modification) 22 ... Electrodes 23 to 26 ... Joining part in honeycomb carrier 31, 32 ... Joining part between ring and honeycomb carrier 33 ... Contact part 41 ... Self Exothermic type honeycomb carrier (second embodiment) 42 ... Electrodes 45, 46 ... Bonding part in honeycomb carrier 47 ... Ring-honeycomb carrier bonding part 49 ... Downstream ring 71 ... Meta Le honeycomb carrier 72 ... Flat plate 73 ... Corrugated plate 79 ... Corrugated plate trough 80 ... Laser head 81, 82 ... Laser displacement sensor

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location B01D 53/94 B01J 35/02 ZAB G F01N 3/20 ZAB K

Claims (33)

[Claims] 1. A self-heating type metallic catalytic converter arranged in an exhaust path of an engine, wherein a honeycomb carrier carrying a catalytic substance comprises a metallic flat plate and a corrugated plate. / Or at least a part of the corrugated sheet is formed with a slit portion as an opening, and a part of the layers formed by alternately laminating and / or winding the flat plate and the corrugated sheet are joined, A current inflow / outflow portion that allows an electric current to flow in the axial direction of the honeycomb carrier is provided in the slit portion of the flat plate and / or the corrugated plate, and the current inflow / outflow portion is bonded around the honeycomb carrier. A rod-shaped electrode that is joined to the ring and protrudes to the outside through the mounting hole of the outer cylinder, and the rod-shaped electrode is fixed to the outer cylinder via an insulating member and a gasket member. A self-heating catalytic converter characterized in that 2. The self-heating catalytic converter according to claim 1, wherein the joint portion of the honeycomb carrier and the joint portion between the ring and the honeycomb carrier are not provided in the same radial cross section of the honeycomb carrier, and the central axis is not provided. A self-heating type catalytic converter, which is provided so as to be displaced in the direction. 3. The self-heating catalytic converter according to claim 2, wherein the joint portions provided in the same radial cross section of the honeycomb carrier occupy 50% or more of the flat plate and corrugated plate contact portions. A self-heating catalytic converter characterized by. 4. The self-heating catalytic converter according to claim 2 or 3, wherein the joints in the same radial cross section of the honeycomb carrier are provided at two or more positions different in the central axis direction. The self-heating type catalytic converter is characterized in that 5. The self-heating type catalytic converter according to claim 4, wherein an interval between two joining portions provided in adjacent honeycomb carriers in the same radial cross section is 2 mm.
A self-heating catalytic converter characterized by the above. 6. The self-heating catalytic converter according to claim 2, wherein a gap between the joint portion inside the honeycomb carrier and the joint portion between the ring and the honeycomb carrier is 2.
A self-heating catalytic converter characterized by having a diameter of not less than 30 mm and not more than 30 mm. 7. The self-heating catalytic converter according to claim 2, wherein the joint between the ring and the honeycomb carrier is provided on an arbitrary cross section that crosses the honeycomb carrier and the ring. Characteristic self-heating catalytic converter. 8. The self-heating catalytic converter according to claim 7, wherein the joint between the ring and the honeycomb carrier is partially provided on the ring. 9. The self-heating catalytic converter according to claim 7, wherein the joint between the ring and the honeycomb carrier is provided at two or more positions different in the central axis direction. A self-heating catalytic converter. 10. The self-heating catalyst according to claim 9, wherein two or more different ring-honeycomb carrier joints are provided in the same radial cross section. converter. 11. The self-heating type catalytic converter according to claim 2, wherein the honeycomb carrier is provided with a joining portion by laser beam joining. 12. The self-heating catalytic converter according to claim 2, wherein the joint portion between the ring and the honeycomb carrier is provided by laser beam joining. 13. The self-heating catalytic converter according to claim 1, wherein the electrodes are provided at positions displaced in the central axis direction, avoiding the same radial cross section as the joint between the ring and the honeycomb carrier. A self-heating type catalytic converter characterized by having 14. The self-heating catalytic converter according to claim 1, wherein the electrodes are provided at positions displaced in the central axis direction while avoiding the same radial cross section as the joint portion of the honeycomb carrier. Characteristic self-heating catalytic converter. 15. The self-heating catalytic converter according to claim 1, wherein the joint portion between the ring and the honeycomb carrier is provided so as to avoid the radial straight line connecting the center point of the honeycomb carrier and the electrode. A self-heating catalytic converter characterized by. 16. The self-heating catalytic converter according to claim 1, wherein the front and rear rings are supported by three or more rod-shaped electrodes, respectively. 17. The self-heating catalytic converter according to claim 16, wherein the number of rod-shaped electrodes supporting each ring is an odd number. 18. The self-heating catalytic converter according to claim 16 or 17, wherein rod-shaped electrodes provided in each ring are evenly arranged in the circumferential direction. . 19. The self-heating catalytic converter according to any one of claims 16 to 18, wherein each one of + and-electrode bolts is longer than the other electrode bolts. . 20. The self-heating type catalytic converter according to claim 16, wherein one of the + electrode bolts is used.
A self-heating catalytic converter characterized in that the book is longer than the other electrode bolts. 21. The self-heating catalytic converter according to claim 16, wherein one of the negative electrode bolts is used.
A self-heating catalytic converter characterized in that the book is longer than the other electrode bolts. 22. The self-heating catalytic converter according to any one of claims 16 to 21, wherein front and rear rod-shaped electrodes are installed on substantially the same radial surface in the central axis direction of the honeycomb carrier. A self-heating catalytic converter. 23. In the self-heating catalytic converter according to claim 16, the electrode bolt on the side electrically grounded to the outer cylinder and the flange is thinner than the electrode bolt on the side not grounded. A self-heating catalytic converter characterized by. 24. The self-heating catalytic converter according to claim 23, wherein the upstream electrode bolt is grounded to the outer cylinder and the flange. 25. The self-heating catalytic converter according to claim 1, wherein the outer cylinder is divided into the same number as the number of + and / or-electrodes. 26. The self-heating catalytic converter according to claim 25, wherein the outer cylinder is evenly divided into a plurality of portions in the circumferential direction. 27. The self-heating type catalytic converter according to claim 25 or 26, wherein the outer cylinder member is provided with a hole through which an electrode is inserted. 28. The self-heating catalytic converter according to claim 27, wherein a hole is provided at a position avoiding the dividing line of the outer cylinder. 29. The self-heating catalytic converter according to claim 27, wherein the outer cylinder member is provided with two holes for + electrode and − electrode. Self-heating catalytic converter. 30. The self-heating catalytic converter according to claim 29, wherein the two holes provided in the outer cylinder member are arranged substantially on the same line in the direction of the central axis of the outer cylinder. Type catalytic converter. 31. The self-heating catalytic converter according to claim 2, wherein the honeycomb carrier has at least one bonded portion within a range of 1 mm or more and 10 mm or less from both ends of the mesh formed by the slits. A self-heating type catalytic converter characterized by being provided in more than one place. 32. The self-heating catalytic converter according to claim 6, wherein a ring-honeycomb carrier joint is provided at an intermediate portion of the honeycomb carrier joints provided in two axially adjacent radial cross sections. A self-heating catalytic converter characterized by being provided. 33. The self-heating catalytic converter according to claim 6, wherein the honeycomb carrier joints provided in the same radial cross section of the honeycomb carrier are located upstream of the joint between the ring and the honeycomb carrier. A self-heating catalytic converter characterized by being located.