JPH06106068A - Electrical heating type honeycomb body - Google Patents

Abstract

PURPOSE:To provide the electric heating type honeycomb body which can be heated up at the time of cold starting by regulating the section from the central part electrode material in the axial direction of the honeycomb body to the outer periphery, providing this section with a space region and brazing the contact parts of the flat planar band materials and corrugated band materials within the space region. CONSTITUTION:The flat planar band materials 1 and corrugated band materials 2 made of thin metallic sheets are so wound and laminated as to come into contact with each other to form many mesh-like vent hole paths 3. The one section 5 inclusive of the plane from the central part electrode material B1 in the axial direction to the outer peripheral surface of the honeycomb body H is regulated in the honeycomb body H. The space region Z of a desired width W inclusive of this section 5 is regulated and the contact parts 12 of the flat planar band materials 1 and corrugated band materials 2 existing within the space region Z are brazed. The current densities flowing in the respective band materials 1, 2 and contact parts 12 are approximately uniformized respectively near the electrode material B2 of the outer peripheral part and the electrode material B1 of the central part, by which the honeycomb body H is internally uniformly heated up.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention generally relates to an exhaust gas purifying apparatus which is used as an exhaust gas purifying means for an automobile by being interposed in an exhaust pipe system. More specifically, the present invention provides
The present invention relates to an electrically heated honeycomb body incorporated in an exhaust gas purification device in order to solve a major drawback of this type of exhaust gas purification device, that is, a problem of a low purification rate of exhaust gas at engine start (cold start). .

[0002]

2. Description of the Related Art Conventionally, as a catalyst supporting base which is a main component of this type of exhaust gas purifying apparatus, a monolith type of Ceramox using a Ceramox material such as cordierite and a metal (metal) type are used. A monolith type is known. Particularly in recent years, a metal monolith type has been actively studied from the viewpoints of mechanical strength, durability, electric resistance, purification efficiency, downsizing of a device, and the like. In the following description, for convenience of description, the latter metal monolith type will be mainly described. A metal monolith type exhaust gas purifying apparatus generally stacks a flat plate-shaped strip made of a heat-resistant thin steel plate and a corrugated strip made by corrugating the thin steel plate so as to have mutual contact portions. Then, a honeycomb laminated body (hereinafter referred to as a honeycomb body) having a large number of mesh-like vent holes (hereinafter referred to as cells) for the exhaust gas passage in the axial direction, which is manufactured by stacking and stacking them in a spiral shape .) And a cylindrical metal case with both ends open for filling and fixing the honeycomb body. The honeycomb body and the metal case are formed so as to withstand thermal expansion and thermal stress that occur in the high temperature of the exhaust gas itself and the high temperature atmosphere due to the exothermic reaction between the exhaust gas and the purification catalyst, and to drive the vehicle. It is firmly fixed by brazing or welding so that it can withstand severe vibrations. It goes without saying that the abutting portions of the flat plate-shaped band member and the corrugated plate-shaped band member forming the honeycomb body are fixed by various methods.

The major problems in this type of exhaust gas purifying apparatus are as follows. That is, when the engine is started (at the time of cold start), the optimum temperature at which the exhaust gas purifying catalyst such as Pt, Pd, and Rh carried on the wall surface of the metal honeycomb body efficiently causes a catalytic reaction with the exhaust gas. This means that the conditions have not been reached, and most harmful substances such as CO (carbon monoxide) and HC (hydrocarbon compounds) emitted from the engine are not purified but are released into the atmosphere. . And this point is going to be a problem from the viewpoint of pollution control.

Various proposals have been made in order to solve the problems at the time of starting the engine (at the time of cold starting). For example, (i) Japanese Utility Model Application Laid-Open No. 63-67609 discloses a converter using a ceramic monolith type as a main catalyst supporting base, which is manufactured in advance in a honeycomb shape in the vicinity of the exhaust gas upstream side of the main catalyst supporting base. A method of coating a metal carrier with alumina, and disposing a metal monolith catalyst capable of energization, (ii) Actual Kaihei 2-94
No. 316 is a system in which a far-infrared heater is arranged on the outer peripheral portion of the catalyst body, and (iii) No. 3-1022 of Kaikaihei is a heater on the front surface (upstream side of exhaust gas) of a monolith type catalyst. A method of arranging a rectifying plate for rectifying exhaust gas on the front surface of the heater, (iv) JP-A-2-277916 discloses that a desired number of corrugated strips are folded in a bellows shape to form a bundle. As a body, a method has been proposed in which an electrical insulator is arranged between adjacent layers of the bundle and an electric contact is fixed to each end of the bundle. However, these conventional proposals have an insufficient heating temperature and a heating temperature in view of the demand for heating the honeycomb body having a heater function sufficiently high to efficiently perform the catalytic reaction. The distribution is not uniform, the cost is increased to solve the problem, and the strength of the honeycomb body itself is insufficient.

[0005]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention has been made to solve the problems found in the above-described conventional honeycomb body having a heater function. The present inventors have made various studies on a technique for raising the temperature of the honeycomb body, particularly the entire inside of the honeycomb body, to a uniform and sufficiently high temperature during cold start. In particular, the inventors have earnestly studied to improve the electrically heated honeycomb body for an exhaust gas purifying apparatus proposed in Japanese Utility Model Laid-Open No. 63-67609 described in the prior art.

As a result, the inventors of the present invention applied the heat-resistant thin metal plate flat plate-shaped strip material and corrugated plate-shaped strip material proposed in Japanese Utility Model Laid-Open No. 63-67609 described above. Stacked so as to be in contact with each other, and wound to form a wound-type honeycomb body, and an electrode material is arranged at the center and the outer periphery of the honeycomb body to form a preheater (the above-mentioned prior art , Furthermore, the wall surface of the honeycomb body is coated with alumina, which is recognized to support the exhaust gas purification catalyst in the formed coating layer.)
Found the following drawbacks. For example,
In the honeycomb body as an electric heating type preheater having the above structure, the outer peripheral electrode material of the honeycomb body is a + (positive) electrode and the central electrode material is a-(negative) electrode with respect to an external power source (battery, etc.) (A) Outer peripheral electrode material (when the honeycomb body is fixed in, for example, a conductive cylindrical metal case, the entire metal case becomes the outer peripheral electrode material). The ratio of the current-carrying area formed by the flat plate-shaped band material and the corrugated plate-shaped material per unit volume in the outer peripheral portion of the honeycomb body and the vicinity thereof to the surface area of the honeycomb body (in other words, the ratio of the current density in the portion. I can.)
(B) Ratio of the current-carrying area formed by the flat plate-shaped strip and the corrugated strip-shaped strip per unit volume in the central portion of the honeycomb body and the vicinity thereof to the surface area of the central electrode material (for example, Ni round bar material) ( In the ratio of the current density at the site),
Since the former (a) is overwhelmingly larger, the current density flowing through the walls of each cell of the former is extremely smaller than that of the latter, in other words, by the energization, in the outer peripheral portion of the honeycomb body and the vicinity thereof. The amount of heat generated by resistance heating is
The heat generation amount is smaller than the heat generation amount obtained by resistance heating in the central portion of the honeycomb body and its vicinity. As a result, the temperature inside the honeycomb body as the preheater becomes uneven.

Therefore, an exhaust gas purifying apparatus incorporating an electrically heated honeycomb body having a conventional preheater function (the outline of the entire apparatus is the same as that shown in FIG. 11 to be described later, the following description will be given). 11 is referred to in Fig. 11), the inside is not heated and heated uniformly due to energization, and the exhaust gas passing through the inside is heated non-uniformly to the main catalyst (MC: Main Converter) on the downstream side. Reach That is, the exhaust gas flows into the main catalyst (MC) without being uniformly heated to the optimum temperature for the catalytic reaction, and as a result, optimum exhaust gas purification cannot be achieved.
Further, in the conventional electrically heated honeycomb body, when the central portion is heated to an appropriate temperature due to the difference in the current density, the outer peripheral portion becomes low temperature, but when the outer peripheral portion is heated to an appropriate temperature in order to eliminate this, the central portion, particularly the central portion. Areas near the electrode material overheat, and in extreme cases melt down
As a result, the vibration resistance durability (mechanical strength) of the honeycomb body is greatly impaired.

On the other hand, in the structure of the conventional honeycomb body having the preheater function, the present inventors have described the electrode material (the center electrode material B) as described in (a) and (b) above.
₁ , energization area (current density) for the outer peripheral electrode material B ₂ )
It has been found that the inside of the honeycomb body is uniformly heated and that a high exhaust gas purification rate is achieved when a means for making the above is substantially the same is taken. An object of the present invention is to provide an exhaust gas purifying apparatus based on the above knowledge, and in particular an electric heating type honeycomb body which is a main constituent element thereof and has excellent heater characteristics.

As is well known, an exhaust gas purifying device incorporating an electrically heated honeycomb body is an EHC in the industry.
(Electrically Heated Converter) is called. This is the overall name including the main catalyst (MC).
On the other hand, the present invention particularly improves the structure of the electrically heated honeycomb body, and in the following description, the EHC
In connection with the electric heating type honeycomb body, EHH (Electric
ally Heated Honeycomb). The honeycomb body itself may be abbreviated as H (Honeycomb).

[0010]

The present invention will be summarized as follows.
According to the present invention, the casing and the central portion are used as the outer peripheral electrode material and the central electrode material, respectively, and the flat metal strip and the corrugated metal strip made of a thin metal plate are contacted with each other around the central metal material. In an electric heating type honeycomb body having a structure in which a honeycomb body manufactured by stacking the honeycomb body is fixed in the casing, as the honeycomb body, a flat plate-shaped band member and a corrugated plate-shaped band member forming the honeycomb member are brought into contact with each other. For the brazing of the part, at least one cross section including a flat surface or a curved surface extending from the central electrode material in the axial direction of the honeycomb body to the outer peripheral part of the honeycomb body is selected, and the cross section is preferably included on the front surface of the honeycomb body. Width (W)
An electric heating type honeycomb body, wherein the cross section is moved in parallel within the desired width (W) to form a space locus, and a contact portion in the space locus is brazed. It is about. In other words, in the electrically heated honeycomb body of the present invention, the honeycomb body has (i) a cross section made of a flat surface or a curved surface extending from the central electrode material in the axial direction of the honeycomb body to the outer peripheral portion of the honeycomb body. (Ii) at least two space regions (Z) having a desired width (W) including the cross section are defined in the honeycomb body, and (iii) a flat plate shape in the space region (Z) An electrically heated honeycomb body, characterized in that a contact portion between a strip material and a corrugated strip material is brazed.

The technical construction and embodiments of the present invention will be described below with reference to the drawings. Needless to say, the present invention is not limited to the illustrated one.

First, the relationship between the electrically heated honeycomb body (EHH) of the present invention and the exhaust gas purifying device (A) will be described. Generally, the electric heating type honeycomb body (EHH) having the preheater function of the present invention is used by being incorporated in the exhaust gas purifying device (A) in the mode shown in FIG. FIG. 11 shows an electrically heated honeycomb body (EHH)
It is sectional drawing which abbreviate | omitted a part of exhaust gas purification apparatus (A) incorporating. As shown in the figure, the exhaust gas purifying apparatus (A) has an electrically heated honeycomb body (EHH) on the upstream side of the exhaust gas and Pt, Pd, Rh on the downstream side with respect to the exhaust gas flow direction (F). A metal case (C ₁ ) for the main catalyst (MC) carrying a catalyst for purification of exhaust gas such as
It is arranged inside. The electrically heated honeycomb body (EHH) is composed of the honeycomb body (H), the central electrode material (B ₁ ), and the outer peripheral electrode material (B ₂ ), and these electrode materials (B ₁ , B ₂ ) is connected to the external power source section (4) by the conducting wires (41, 42). It should be noted that in the arrangement of the electrically heated honeycomb body (EHH), it is necessary to pay attention to the insulation from other members, but this is omitted in FIG. 11 for simplification. In the present invention, a catalyst may be supported on the honeycomb body (H) in order to improve the heater characteristics of the EHH as described later, but in such a case, the main catalyst (MC) may be excluded. Needless to say. That is, in such a case, EHH
Will also have the function of MC.

FIG. 12 is a front view of the honeycomb body (H) portion of the electrically heated honeycomb body (EHH) shown in FIG. As shown in FIG. 12, the honeycomb body (H), which is a main component of the electric heating type honeycomb body (EHH) of the present invention, is generally a flat metal strip (1) made of a thin metal plate and a corrugated plate shape. It is manufactured by winding and laminating the strips (2) so as to abut each other. As a result, a large number of abutting portions (12) of both strips (1, 2) and a large number of exhaust gas mesh vent holes (cells) (3) are automatically formed. The outer peripheral electrode material (B ₂ ) also plays the role of the casing (C ₂ ) of the honeycomb body (H) (B ₂ = C ₂ ).

Next, the electrically heated honeycomb body of the present invention (E
In HH), the technical means for uniformly heating the inside of the honeycomb body (H), which is the main component of the HH) when energized, will be described.

In the honeycomb body (H) produced by laminating the flat strip (1) made of a thin metal plate and the corrugated strip (2) so as to be in contact with each other, the flat strip ( When brazing (brazing) the contact portion (12) between the corrugated plate material (1) and the corrugated strip (2), a brazed portion (brazing portion) and a non-brazing portion (non-brazing portion) When provided, a large difference in electrical resistance occurs between the two. Needless to say, the plate-shaped strip (1) and the corrugated strip (2) are mechanically abutted in the non-brazing part,
The electrical resistance is higher than that of a case where both strip materials (1, 2) are completely joined by a brazing material. When the honeycomb body (H) manufactured by such a brazing mode is energized, most of the electric current flows to the brazed portions, and resistance heating occurs in the channels of these brazed portions. become. Further, in the strip material (1, 2) of the non-brazing portion of the present invention, when an electrically insulating layer, for example, an insulating layer of Al ₂ O ₃ is provided on the outer surface of the strip material (1), the brazing portion is surely subjected to a Since it is possible to flow the heat, the amount of resistance heat generation can be accurately controlled in relation to the size of the brazing portion.

In the present invention, the inside of the honeycomb body (H) is uniformly and electrically heated by utilizing the difference in resistance heating inside the honeycomb body (H) manufactured under the above brazing mode. I am trying. Hereinafter, a brazing mode applied to the honeycomb body (H) according to the present invention for uniformly heating the inside of the honeycomb body (H) during energization will be described with reference to the drawings.

1 and 2 show the honeycomb body (H) of the present invention.
It is a figure for demonstrating the brazing aspect of 1st Example applied to. FIG. 1 is a cross-sectional view through the central electrode material (B ₁ ) of the electrically heated honeycomb body (EHH) of the present invention, from the central electrode material (B ₁ ) to the outer peripheral portion of the honeycomb body (H). A cross section (5) is shown. FIG. 2 is a front view of the electrically heated honeycomb body (EHH) shown in FIG. In FIG. 2, the shaded portion of the width (W) indicates the brazing portion (6), and the white background portion indicates the non-brazing portion (7). The brazing part (6) extends over the entire width (l _o ) of the honeycomb body including the cross section (5) (in the direction perpendicular to the paper surface in FIG. 2).

That is, the honeycomb body (H) is brazed in the following manner. First, as shown in FIG. 1, the central electrode material (B ₁ ) in the axial direction of the honeycomb body (H)
And a cross section (5) including a flat surface extending to the outer peripheral surface of the honeycomb body (H) and having a desired width (W) including the cross section (5) as shown in FIG. Stipulates
The abutting portion (12) of the flat strip (1) and the corrugated strip (2) existing in the space region (Z) is brazed. Needless to say, the brazing portion (6) shown by the hatched portion in FIG. 2 coincides with the space region (Z). By the brazing mode as described above, the outer peripheral electrode material (B ₂ ) is supplied by the power supply from the external power source part (4).
And the current densities flowing through the strip members (1, 2) and the contact portions (12) of the strip members (1, 2) in the vicinity of the central electrode material (B ₁ ) are substantially the same. Therefore, the inside of the honeycomb body (H) can be uniformly heated and heated.

In the present invention, it goes without saying that the cross section (5) may be a flat surface or a curved surface having a desired shape. In addition, as shown in FIG. 2, four planar cross-sections (5) are defined in the honeycomb body, and the space region (Z) is centered on the central electrode material.
It is specified at a symmetrical position of °. In the present invention, the angle (α) formed by the symmetrical space region (Z) is defined by 360 ° / n (where n = 2, 3 ...), where n corresponds to the number of cross sections. Is. In the present invention, needless to say, the spatial regions (Z) may be arranged not only symmetrically but also asymmetrically, as shown in Examples described later. .

[0020] In the present invention, the outer diameter (d) and the honeycomb body of the relationship between the outer diameter (d) of the desired width (W) and the center electrode member (B _1), and the center electrode member (B ₁₎ ( Regarding the relationship between the outer diameter (D) of H) (see FIG. 2), it has been found from experiments by the present inventors that it is preferable to establish the relationship by the following equations (1) and (2). This allows W to be set reasonably. d / 5 ≤ W ≤ 5d (1) D / 15 ≤ d ≤ D / 5 (2) Note that the above relational expression is a tentative guideline for the central electrode material (B ₁ ). If a large width (W) value is adopted with respect to the outer diameter (d), the current density in the region near the central electrode material (B ₁ ) increases, which causes abnormal heating and melting damage of the region. You have to be careful. The brazing mode of the honeycomb body (H) of the present invention shown in FIGS.
It is related to d.

In the present invention, the flat metal strip (1) used for producing the honeycomb body (H) constituting the electric heating type honeycomb body (EHH) is an ordinary metal monolith type main catalyst. Strips used in the production of the carrier matrix (MC), such as chrome steel (chrome 13-25
%), Heat-resistant stainless steel such as Fe-Cr 20% -Al 5%, or heat-resistant stainless steel in which a rare earth element is added to improve the oxidation resistance.
Use strips of 4 mm to 0.1 mm. As the corrugated strip material (2), the corrugated plate material (1) corrugated so as to have a predetermined substantially sine wave or substantially trapezoidal wave is used. In addition, Ni-Cr alloys, Ni-Cr-Fe alloys, Ni-Cr-Al-Fe alloys, and the like are also used in consideration of the electrical conductivity of the honeycomb body (H) at high temperatures.

In the present invention, in particular, in order to improve the heater characteristics of the electric heating type honeycomb body (EHH) as will be described later, an exhaust gas purifying catalyst is used by being supported on the wall surface of the honeycomb body (H). be able to. In such a case, a member forming the honeycomb body (H), that is, a flat strip (1) and a corrugated strip (2) containing Al, or an Al layer was provided on the surface thereof. Heat treat things,
It is preferable to deposit a whisker-like or mushroom-like alumina (Al ₂ O ₃ ) layer on the surface thereof.
The whisker-like alumina layer is preferable because it can firmly hold the washcoat layer for carrying the exhaust gas purifying catalyst such as Pt, Pd, and Rh as described later.

As described above, in the electric heating type honeycomb body (EHH) of the present invention, in order to improve the heater characteristic (heating characteristic), the electric heating type honeycomb body (EHH) is used.
The exhaust gas purifying catalyst can be used by supporting it on the wall surface of the honeycomb body (H), which is a main component of (H). As is well known, HC (hydrocarbon compound) and CO (carbon monoxide) in the exhaust gas are oxidant (Pt,
C due to an exothermic reaction under Pd, Cr, V, Cu, etc.)
It is rendered harmless by O ₂ and H ₂ O. Further, an oxidation-reduction (three-way) catalyst (Pt-Rh system, Pt-) that simultaneously purifies HC, CO, and NOx discharged into the exhaust gas near the stoichiometric air-fuel ratio
(Pd-Rh system, etc.) is well known, and these exhaust gas components are oxidized to CO ₂ or H ₂ O or N ₂
Will be reduced to. Even in the three-way catalyst system, the catalytic reaction progresses exothermically as a whole.

In the present invention, the meaning of carrying the exhaust gas purifying catalyst on the side of the honeycomb body (H) is to improve the purifying ability of the exhaust gas purifying apparatus (A) as a whole, and to carry out the catalytic reaction as described above. The effective amount of heat generation is based on this, and this heat generation amount is used to improve the heater characteristics. In the present invention, as the catalyst to be supported on the wall surface of the honeycomb body (H), an oxidation catalyst is preferable in view of the amount of heat generation, as can be seen from the above-mentioned catalytic reaction, but a redox (three-way catalyst) (a three- way catalyst). In addition,
The method of supporting these catalyst components will be described in the main catalyst (MC) described later.

Electric heating type honeycomb body (EHH) of the present invention
The arrangement relationship (energization connection) between the external power source section (4) and the external power source section (4) may be as shown in FIG. 1, and when viewed from the exhaust gas purifying apparatus (A) as a whole, as shown in FIG. In the present invention, although not shown, the power supply from the external power supply unit (4) to the electrode materials (B ₁ , B ₂ ) may be performed with a timer for a limited period of time, or a desired honeycomb body may be provided. The temperature of the honeycomb body and the temperature of the exhaust gas may be measured by a sensor (thermocouple or the like) attached to the portion so that the honeycomb body is turned on and off at a desired set value, and the mode is not limited in any way. Also, the external power supply unit (4)
Although the DC power supply is illustrated as an example, it goes without saying that an AC power supply may be used.

FIG. 3 is a view for explaining the brazing mode of the second embodiment applied to the honeycomb body (H) of the present invention, and corresponds to FIG. 2 described above. The second embodiment is
Compared with the first embodiment, two planar cross-sections (5) shown in FIG. 1 are set, and the angle formed by the space region (Z), α
= 180 °, the other technical configurations are the same. By such a brazing mode, it is possible to make the current densities in the vicinity of the two electrode materials (B ₁ , B ₂ ) substantially the same during energization. Therefore, the inside of the honeycomb body (H) can be uniformly heated and heated by such a brazing mode.

FIG. 4 is a view for explaining the brazing mode of the third embodiment applied to the honeycomb body (H) of the present invention, and corresponds to FIG. The third embodiment is
Compared to the first embodiment, the first embodiment has W> d.
In contrast, the third embodiment is different in that W <d, but the other technical configurations are the same. With such a brazing mode, both electrode materials (B ₁ , B ₂ ) are energized when electricity is applied.
The current densities in the vicinity of can be made substantially the same.

FIG. 5 is a view for explaining the brazing mode of the fourth embodiment applied to the honeycomb body (H) of the present invention and corresponds to FIG. The fourth embodiment is
Compared with the first embodiment, eight planar cross-sections (5) shown in FIG. 1 are set inside the honeycomb body, and α = 45 °, and W <d. Although different in points, the other technical configurations are the same. Even in such a brazing mode, it is possible to make the current densities in the vicinity of the two electrode materials (B ₁ , B ₂ ) substantially the same during energization.

FIG. 6 is a view for explaining the brazing mode of the fifth embodiment applied to the honeycomb body (H) of the present invention,
This corresponds to FIG. In the fifth embodiment, the cross section (5) of the first to fourth embodiments is flat,
The cross section (5) is a curved surface, and the curved surface has a space region (Z)
Is defined. The fifth embodiment has exactly the same configuration as that of the second embodiment shown in FIG. 3 except that the cross section (5) is a curved surface.

FIG. 7 is a diagram for explaining the brazing mode of the sixth embodiment applied to the honeycomb body (H) of the present invention.
The space region (Z) of the first to fifth embodiments has an angle (α) formed by the space regions (Z) of 360 ° / n with the center electrode material (B ₁ ) as the center. It is defined in the target position. On the other hand, the sixth embodiment shown in FIG. 7 is defined in an asymmetrical position. The other technical constitution is exactly the same as that of the first embodiment.

FIG. 8 is a view for explaining the brazing mode of the seventh embodiment applied to the honeycomb body (H) of the present invention.
The seventh embodiment is a spatial region (Z ₁ ) having a predetermined width (W ₁ ) including a predetermined planar cross section (5) defined in the honeycomb body (H).
₁ ) and a spatial region (Z ₂ ) having a predetermined width (W ₂ ) including the other planar cross section (5) are combined (Z = Z ₁ + Z ₂ ) to form (W ₁ ≠ W ₂ ). The other technical constitution is exactly the same as that of the first embodiment.

FIG. 9 shows an eighth embodiment of the present invention. In the eighth embodiment, the cross-sectional shape of the honeycomb body (H) is
The other technical constitution is exactly the same as that of the first embodiment except that it is of a racetrack shape.

FIG. 10 shows a ninth embodiment of the present invention. The ninth embodiment has exactly the same technical configuration as the first embodiment except that the honeycomb body (H) has a substantially triangular cross section.

In the present invention, in order to perform the brazing of the first to ninth embodiments, the brazing material may be supplied to the strips (1, 2) by an appropriate method. For example, when the flat strip (1) and the corrugated strip (2) are roll-formed into a honeycomb body (H), at least one of the strips (1, 2) The brazing material may be supplied by coating to the necessary portions of. Alternatively, the brazing material coating liquid may be supplied to a necessary portion of the strip at the time of winding the strip while synchronizing with the winding speed. From the viewpoint of saving the brazing material, durability of the honeycomb body, and the like, it is preferable to supply the brazing material to a necessary portion of the top portion (mountain or valley) of the corrugated strip (2). In the present invention, in order to enhance the electric insulation of the non-brazing portion other than the brazing portion, the brazed honeycomb body is subjected to an oxidation treatment, or the portion is coated with alumina slurry, and heat-treated to form the portion. An electrically insulating alumina coating layer may be formed on. The above-mentioned formation of the alumina coating layer may be carried out at the same time when the flat strip (1) and the corrugated strip (2) are roll-formed into the honeycomb body (H). For example, the alumina slurry may be applied to the portion to which the brazing material is not supplied at the time of roll forming.

Electric heating type honeycomb body (EHH) of the present invention
Is generally the main catalyst (MC) as shown in FIG.
It is arranged and used in the front part of. The main catalyst (MC) will be described below. Exhaust gas purification device (A)
The other main component of the main catalyst (MC) is
It may be a ceramic monolith type,
Alternatively, it may be of a metal monolith type. These may be manufactured according to a conventional method. For example, a main catalyst supporting base material that is a precursor of the main catalyst (MC) may be manufactured and an exhaust gas purifying catalyst may be supported thereon.
Hereinafter, a method for producing a metal-made monolithic main catalyst supporting base will be described, but the main catalyst supporting base applicable to the present invention is not limited thereto. The method of supporting the catalyst will be described later.

First, there is a winding type main catalyst supporting base having a circular cross-sectional shape. This is manufactured by stacking heat-resistant thin metal plate flat strips (1) and corrugated strips (4) so that they come into contact with each other, and winding and stacking them in a spiral shape at once. It The winding lamination automatically forms a large number of mesh-like vent holes (cells) (3) which serve as exhaust gas passages. The wound type honeycomb body (H), which is a main component of the electric heating type honeycomb body (EHH) described above, is also manufactured by this method. More specifically, it may be manufactured as follows. Fe-Cr 20% -Al 5%-
Ce 0.02% heat resistant steel thickness 0.04mm, width 38mm
A flat strip made of thin steel strip is passed between the forming gears to form a corrugated strip with a pitch width (3.0 mm) and a wave height (1.4 mm). Then, the flat strip and the corrugated strip produced by corrugating the flat strip are stacked one on top of the other, and the end portion is inserted into the slit portion of the slit forming rod.
For example, the metal main catalyst supporting base material having an outer diameter of 70 mm and having a large number of mesh-like vent holes (cell density of 300 cpsi) in the axial direction may be laminated in a batch.

Next, there is a hierarchy type main catalyst supporting base material having a circular cross-sectional shape. This is manufactured by stacking heat-resistant flat-plate strips (1) and corrugated strips (2) made of thin metal plates in a layered manner so as to abut each other.

There is a radial type main catalyst supporting base having a circular sectional shape. This is a purification element (E) by abutting the flat band material (1) made of a heat-resistant thin metal plate and the corrugated plate material (2), and fixing a desired number of the purification elements (E). It is manufactured by radially extending from the axis (S) as a starting point.

There is an S-shaped main catalyst carrier having a circular cross section. This is a purification element (E) by bringing a flat band material and a corrugated plate material made of a heat-resistant thin metal plate into contact with each other so that the purification element (E) becomes a flat band material at the outermost surface. The purification elements (E) are stacked in layers and bent in opposite directions about the two fixed points (S ₁ , S ₂ ) set on the upper and lower outermost surfaces, that is, the purification elements (E) ) Is bent into a substantially S-shaped curve.

In order to support the exhaust gas purifying catalyst such as Pt, Pd and Rh on the main catalyst supporting base having various structures manufactured as described above, a usual method may be adopted. For example, first, a catalyst supporting layer for supporting the catalyst on the wall surface of the main catalyst supporting base having a honeycomb structure is formed. To this, a slurry in which activated alumina (γ-Al ₂ O ₃ ) powder and alumina sol are mixed is applied, and 60
The heat treatment may be performed at 0 ° C. Next, in order to support the catalyst such as Pt, Pd, and Rh catalyst on the catalyst supporting layer thus formed, a usual method such as impregnation treatment may be adopted to support the catalyst component. The main catalyst (MC) is manufactured as described above.

Electric heating type honeycomb body (EHH) of the present invention
Is generally fixed in a metal case (C ₁ ) together with the main catalyst (MC) described above to manufacture an exhaust gas purifying apparatus (A) as shown in FIG. 11. Such a metal case (C ₁ ) is also for accommodating and fixing the electric heating type honeycomb body (EHH) and the main catalyst (MC) inside, and if both ends are open. , Its shape is not subject to any restrictions. As the material of the metal case (C ₁ ), heat resistant steel of the same type as the main catalyst supporting base material may be used, or a material having high heat resistance and corrosion resistance may be used. In addition, a double structure with the outer part of the metal material richer in heat resistance and corrosion resistance than the inner part,
Specifically, it is also possible to use one in which ferritic stainless steel is used for the inner part and austenitic stainless steel is used for the outer part.

[0042]

EFFECT OF THE INVENTION The electrically heated honeycomb body (EH of the present invention
H) is generally a metal case (C) as a main component (precatalyzer) of the exhaust gas purification device (A).
_Although it is used by being arranged on the upstream side of the main catalyst (MC) in ₁ ), it can be used in place of the main catalyst (MC) (as a main catalyst). And the electrically heated honeycomb body (EHH) of the present invention
, The main component of which is the honeycomb body (H)
Employs a novel brazing means so that the temperature distribution of the heat generating portion is uniform when energized and sufficient resistance heating is obtained. Further, the honeycomb body (H) can carry an exhaust gas purifying catalyst on the wall surface thereof in order to improve the heater characteristics (heating characteristics).

Therefore, the following excellent effects are achieved in the present invention. (1) Exhaust gas is uniformly heated in an electric heating type honeycomb body (EHH) and heated to a temperature suitable for catalytic reaction. Can be greatly improved. (2) When the catalyst for exhaust gas purification is carried on the honeycomb body (H) of the electrically heated honeycomb body (EHH), not only the heater characteristics are improved but also the exhaust gas purification ability of the entire exhaust gas purification device (A) is improved. Can be made. (3) Since the constituent members of the electrically heated honeycomb body (EHH) are not locally heated, it is possible to prevent the deterioration of the vibration resistance (mechanical strength) due to the deterioration of the members. (4) Since the electric heating type honeycomb body (EHH) itself serves as a heater, it is not necessary to separately manufacture and dispose the heater material. (5) In the honeycomb body (H), which is a main constituent element of the electric heating type honeycomb body (EHH), the flat plate-shaped strip (1) and the corrugated plate-shaped strip (1) at the central portion of the honeycomb body and the vicinity thereof ( The contact part (12) of 2) has a higher rate of brazing than other parts, so that scoping (protrusion) normally found in the central part of this type of honeycomb body is prevented, and it is excellent for a long time. The heater function can be exhibited.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a first embodiment of the present invention.

FIG. 2 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of the first embodiment of the present invention.

FIG. 3 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a second embodiment of the present invention.

FIG. 4 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a third embodiment of the present invention.

FIG. 5 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a fourth embodiment of the present invention.

FIG. 6 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a fifth embodiment of the present invention.

FIG. 7 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a sixth embodiment of the present invention.

FIG. 8 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a seventh embodiment of the present invention.

FIG. 9 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing aspect of an eighth embodiment of the present invention.

FIG. 10 is a front view of an electrically heated honeycomb body (EHH) for explaining a brazing mode of a ninth embodiment of the present invention.

FIG. 11: Electric heating type honeycomb body (EHH) of the present invention
It is sectional drawing which abbreviate | omitted a part of exhaust gas purification apparatus incorporating.

FIG. 12: Electric heating type honeycomb body (EHH) of the present invention
FIG.

[Explanation of symbols]

A ……………… Exhaust gas purifying device MC ………… Main catalyst EHH ………… Electric heating type honeycomb body H ……………… Honeycomb body constituting electric heating type honeycomb body B ₁ …… ………… Center electrode material B ₂ ……………… Peripheral electrode material C ₁ , C ₂ …… Casing F ……………… Exhaust gas flow direction 1 ……………… Flat plate strip 2… …………… Corrugated strip 12 ……………… Abutting part between flat strip and corrugated strip 3 ……………… Cell (mesh-like vent passage) 4 ………… ...... External power supply section 41,42 ...... Lead wire 5 ……………… Cross section of honeycomb body 6 ……………… Brazed section 7 ……………… Non brazed section

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location F01N 3/24 L H05B 3/00 330 Z Z 8918-3K

Claims (11)

[Claims] 1. A casing and a central portion are used as an outer peripheral electrode material and a central electrode material, respectively, and a flat metal strip and a corrugated metal strip made of a thin metal plate are applied to each other around the central electrode material. In an electric heating type honeycomb body having a structure in which a honeycomb body manufactured by stacking so as to be in contact with each other is fixed in the casing, the honeycomb body is (i) an axial center electrode material of the honeycomb body to the honeycomb body. (Ii) defining at least two or more space regions (Z) having a desired width (W) including the above-mentioned cross section in the honeycomb body, and ) An electrically heated honeycomb body, characterized in that the flat plate-shaped band member and the corrugated plate-shaped band member in the space region (Z) are brazed at their contacting portions. 2. The electrically heated honeycomb body according to claim 1, wherein the outer peripheral electrode material and the central electrode material are connected to an external power source. 3. The spatial region (Z) is defined at a symmetrical position of 360 ° / n (where n = 2, 3, ...) with respect to the central electrode material. The electrically heated honeycomb body according to the item 1. 4. The electrically heated honeycomb body according to claim 1, wherein the space region (Z) is defined at an asymmetric position with respect to the central electrode material. 5. A space region (Z) is provided with a spatial region of the desired width _{(W 1) (Z 1)} , the spatial region (Z another desired width (W ₂₎
The electrically heated honeycomb body according to claim 1, which is a combination of ₂ ). 6. The desired width (W) set on the front surface of the honeycomb body is not less than the outer diameter (d) of the central electrode material (W ≧
The electrically heated honeycomb body according to claim 1, which is d). 7. The electric heating type according to claim 1, wherein the desired width (W) set on the front surface of the honeycomb body is smaller than the outer diameter (d) of the central electrode material (W <d). Honeycomb body. 8. The electrically heated honeycomb body according to claim 1, wherein the surface of the strip material at the non-brazing site of the honeycomb body has an electrically insulating layer. 9. The electrically heated honeycomb body according to claim 8, wherein the electrically insulating layer is composed of Al ₂ O ₃ . 10. The electrically heated honeycomb body according to claim 1, wherein the honeycomb body carries an oxidation catalyst for purifying exhaust gas. 11. The electrically heated honeycomb body according to claim 1, wherein the honeycomb body carries an oxidation-reduction catalyst for purifying exhaust gas.