JP3269646B2 - Exhaust gas purification device - Google Patents

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 used as an exhaust gas purifying means for an automobile, which is interposed in an exhaust pipe. More specifically, the present invention incorporates a heating means which can greatly improve the major drawback of this type of exhaust gas purification apparatus, namely, the problem of low exhaust gas purification rates at the time of engine start (cold start). It relates to an exhaust gas purification device.

[0002]

2. Description of the Related Art Heretofore, as a catalyst supporting base which is a main component of this type of exhaust gas purifying apparatus, a ceramic monolith type using a ceramic material such as cordierite and a metal (metal) type have been used. Monolith type is known. Particularly recently, metal monolith type devices have been actively researched and developed from the viewpoint of mechanical strength, durability, ventilation resistance, purification efficiency, miniaturization of devices, and the like. In the following description, the latter metal monolith type is mainly described for convenience of description. In general, a metal monolith type exhaust gas purifying apparatus stacks a flat strip made of a heat-resistant thin steel sheet and a corrugated strip formed by corrugating the thin steel sheet so as to have an abutting portion. A plurality of mesh-shaped vent passages (hereinafter also referred to as cells) for exhaust gas passages in the axial direction, which are formed by spirally winding and laminating them in a lump or by laminating them in a layered manner. The honeycomb structure includes a honeycomb-shaped laminate (hereinafter, referred to as a honeycomb body) and a cylindrical metal case having both ends opened for loading and fixing the honeycomb body. The honeycomb body and the metal case are designed to withstand thermal expansion and thermal stress generated under a high temperature of the exhaust gas itself and a high temperature atmosphere due to an exothermic reaction between the exhaust gas and the purification catalyst. It is firmly fixed by brazing or welding so that it can endure severe vibration during running. It goes without saying that the contact portions between the flat band material and the corrugated band material constituting the honeycomb body are fixed by various methods.

A major problem with this type of exhaust gas purifier is as follows. That is, at the time of starting the engine (at the time of cold start), the optimum temperature at which the exhaust gas purifying catalyst such as Pt, Pd, Rh supported on the wall surface of the metallic honeycomb body efficiently causes a catalytic reaction with the exhaust gas. The condition is not reached, and most of the harmful substances such as CO (carbon monoxide) and HC (hydrocarbon compounds) emitted from the engine are released to the atmosphere without being purified. .

[0004] Various proposals have been made to solve the problems at the time of starting the engine (at the time of cold start). For example, (i) Japanese Utility Model Application Laid-Open No. 63-67609 discloses that a converter using a ceramic monolith type as a main catalyst supporting matrix is manufactured in advance in a honeycomb shape at a portion near the exhaust gas upstream side of the main catalyst supporting matrix. Coating the coated metal support with alumina and disposing an energizable metal monolith catalyst, (ii) Japanese Utility Model Application
No. 4316 discloses a method in which a far-infrared heater is disposed on the outer peripheral portion of the catalyst body. (Iii) Japanese Utility Model Laid-Open No. 3-10022 discloses a heater on the front surface (upstream of exhaust gas) of a monolithic catalyst, and There has been proposed a method in which a rectifying plate for rectifying exhaust gas is disposed in front of the heater. However, these conventional proposals are required to raise the temperature of the honeycomb body that performs the heater function sufficiently high to perform the catalytic reaction efficiently.
This is not satisfactory because the temperature for raising the temperature is insufficient or the cost is increased for the solution.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems of the conventional honeycomb body. The present inventors have made various investigations on a technique for uniformly and sufficiently raising the temperature of the honeycomb body, particularly the entire inside of the honeycomb body at the time of cold start. In particular, Japanese Utility Model Application Laid-Open No.
The present inventors have enthusiastically studied the improvement of a current-carrying-type honeycomb body for an exhaust gas purifying device proposed in, for example, -67609.

[0006] As a result, the present inventors applied the heat-resistant thin metal sheet flat and corrugated strips proposed in Japanese Utility Model Application Laid-Open No. 63-67609 described as a prior art. A wound type honeycomb body is manufactured by stacking so as to be in contact with each other, and an electrode material is disposed on the center and the outer periphery thereof to form a pre-heater. Coating with alumina, which is recognized to support a catalyst for purifying exhaust gas on the formed coating layer) has been found to have the following disadvantages. For example, in a honeycomb body as an energization-type preheater having the above-described structure, the outer peripheral electrode material of the honeycomb body is connected to a positive pole and the central electrode material is connected to a negative pole with respect to an external power supply unit (such as a battery). When current is supplied, (a) the outer peripheral electrode material (the honeycomb body is fixed in the conductive cylindrical metal case, so the entire metal case becomes the outer peripheral electrode material). The ratio of the energizing area formed by the flat band material and the corrugated band material per unit volume in the outer peripheral portion and the vicinity thereof,
(B) In the ratio of the current-carrying area formed by the flat band material and the corrugated band material per unit volume in the central part and the vicinity part of the honeycomb body to the surface area of the central electrode material (for example, Ni round bar material), Since the former (a) is overwhelmingly more numerous, the current density flowing through the walls of the former cells is much smaller than the latter, in other words, the current at the outer peripheral portion of the honeycomb body and the vicinity thereof due to energization. The calorific value obtained by the resistance heating is smaller than the calorific value obtained by the resistance heating at the central portion of the honeycomb body and the vicinity thereof. As a result, the temperature inside the honeycomb body as the preheater becomes non-uniform.

As is well known, this type of energized heat-generating honeycomb body (H ') having a pre-heater function is used by being incorporated in an exhaust gas purifying apparatus (A) in a manner shown in FIG. . FIG. 8 is a cross-sectional view in which a part of an exhaust gas purifying apparatus (A) incorporating a conventional energized and heated honeycomb body (H ′) is omitted. As shown, in the exhaust gas flow direction (F), an energized heat-generating honeycomb body (H ′) is carried upstream of the exhaust gas, and a catalyst for purifying exhaust gas such as Pt, Pd, Rh or the like is carried downstream. The main (main) catalyst (M) is disposed in the metal case (C) and the exhaust gas purification device (A)
Is configured. And the energized and heated honeycomb body (H ')
The central electrode material (B ₁ ) and the outer peripheral electrode material (B ₂ ) are connected to the external power supply section (4) by conducting wires (5, 6). In the arrangement of the honeycomb body (H '), attention must be paid to the insulating property from other members, but this is omitted in FIG. 8 for simplification.

As described above, in the conventional exhaust gas purifying apparatus (A) shown in FIG. 8, the energized and heated type honeycomb body (H ') having the pre-heater function is not uniformly heated and heated inside by the energization. The exhaust gas passing through the inside is heated unevenly and reaches the downstream main catalyst (M). That is, the exhaust gas flows into the main catalyst (M) without being uniformly heated to the optimal temperature for the catalytic reaction, and as a result, it is not possible to achieve optimal exhaust gas purification. Further, in the conventional energized and heated honeycomb body (H ′),
When the central portion is set to an appropriate temperature due to the difference in current density described above, the outer peripheral portion becomes low in temperature.However, when the outer peripheral portion is set to an appropriate temperature in an attempt to solve this, the central portion, especially the portion near the central electrode material overheats, and in extreme cases, In this case, the honeycomb body (H ′) is melted down (melted), and the vibration resistance durability (mechanical strength) of the honeycomb body (H ′) is greatly impaired.

On the other hand, the present inventors have proposed a conventional pre-
In the structure of the honeycomb body (H ′) having a data function,
As described in (a) and (b) above, the electrode material (the central electrode)
Material B ₁, Outer electrode material B_Two))
If the means to make is taken, the inside of the honeycomb body is heated uniformly
And thus high exhaust gas purification efficiency
Is achieved. The present invention provides the above knowledge
Heat-generating exhaust gas purifier based on
Provide honeycomb body with excellent heater characteristics, which is an essential component
It is intended to be offered.

[0010]

SUMMARY OF THE INVENTION In summary of the present invention,
The present invention relates to an exhaust gas purifying apparatus comprising an energized heating type honeycomb body (H) and a main catalyst disposed at the rear of the honeycomb body, wherein the energized heating type honeycomb body (H) comprises: (i) a thin metal plate; A honeycomb-shaped structure manufactured by stacking a flat plate-shaped strip and a corrugated strip-shaped strip made of aluminum so as to abut each other, and the exhaust gas flow from the center to the outer periphery of the honeycomb-shaped structure. The honeycomb body (H ₁ ) has a width (l) whose width in the direction sequentially decreases, and (ii) the honeycomb body (H ₁ ) is connected to an external power supply at a center portion and an outer peripheral portion. The present invention relates to an exhaust gas purifying apparatus provided with an electrode material.

Hereinafter, a technical configuration and an embodiment of the present invention will be described with reference to the drawings. It goes without saying that the present invention is not limited to the illustrated one.

FIG. 1 is a sectional view of a first embodiment of the present invention, in which a part of a current-carrying-type honeycomb body (H) having a heater function is omitted, and FIG. 2 is a perspective view. The electric heating type honeycomb body (H) of the present invention is used in place of the conventional electric heating type honeycomb body (H ′) shown in FIG. That is, it is disposed and used as a preheater on the upstream side of the main catalyst (M) with respect to the exhaust gas flow direction (F). Electric heating type honeycomb body (H) of the present invention
Differs greatly from the conventional honeycomb body (H ′) in the following points.

(A) A conventional energized heating type honeycomb body (H
8) is a flat strip (1) having a predetermined width (l ') made of a heat-resistant thin metal plate as described above and as shown in FIG.
And a corrugated strip (2) are stacked so that they are in contact with each other, and are wound together in a spiral to produce a wound type honeycomb body. (B ₁ , B
₂ ) is arranged. In addition, as shown in FIG. 2, a large number of exhaust gas reticulated vent passages (cells) (3) are automatically formed by winding and laminating the flat band material and the corrugated band material. Therefore, as shown in FIG. 8, the thickness of the width of the honeycomb body (H ′), that is, the width (l ′) in the exhaust gas flow direction (F) is constant. (B) On the other hand, the honeycomb body (H ₁ ) constituting the energized heating type honeycomb body (H) of the present invention is the same as the conventional one in the sense that it is a honeycomb-shaped structure.
As shown in FIGS. 1 and 2, the width (l) in the exhaust gas flow direction (F) gradually increases (gradually decreases) from the center to the outer periphery of the honeycomb body (H ₁ ) from the center to the outer periphery. Is what you are doing. The electrode material is disposed at the center and the outer periphery of the honeycomb body (H ₁ ), respectively. The width of the electrode material (B ₁ ) at the center and the width of the electrode material (B ₂ ) at the outer periphery are also The difference (B ₁ > B ₂ ) in the width (l) between the central portion and the outer peripheral portion of the honeycomb body (H ₁ ) may be made to correspond.

The differences described above have significant significance. That is, for example, when electricity is supplied in the embodiment shown in FIG. 1, more specifically, the outer peripheral electrode material (B) of the honeycomb body (H) is connected to the external power supply section (4) by the lead wires (5, 6). ₂ ) is connected to the positive electrode side and the central electrode material (B ₁ ) is connected to the negative electrode side, and when energized, the wall of each cell from the outer peripheral electrode material (B ₂ ) to the central electrode material (B ₁ ) (This is, of course, composed of a flat strip (1) and a corrugated strip (2)).
B ₁ in the width of the electrode material itself to reflect that were gradually increases throughout the width of ₁₎ (l) in the outer peripheral portion → center> B ₂
Holds, electricity of substantially the same density flows in any part inside the honeycomb body (H ₁ ).
In other words, electricity flows through conductors (each cell wall) having substantially the same resistance value in the current-carrying path, so that uniform resistance heating can be obtained. This is an advantage that the width of the central portion of the honeycomb body (H ₁ )> the width of the outer peripheral portion, that is, B ₁ > B ₂ correspondingly. The above-mentioned point is the outer peripheral portion electrode material (B) described in the above (a) and (b).
₂ ) The surface area of the central electrode material (B ₁ ) and the ratio of the energization area in the vicinity thereof and the ratio of the energization area in the vicinity thereof and the ratio of the energization area in the vicinity thereof to the surface area of the center electrode material (B ₁ ) are substantially the same in the present invention. It is understandable.

In the present invention, as the flat strip material (1) used for manufacturing the honeycomb body (H ₁ ) constituting the above-mentioned energized and heated type honeycomb body (H), an ordinary metal monolith type main body is used. Strips used in the production of the catalyst carrier, such as chromium steel (chromium 13-25%), Fe-Cr
Use a 0.04 mm to 0.1 mm thick strip of heat-resistant stainless steel such as 20% -Al 5% or heat-resistant stainless steel to which rare earth is added to improve oxidation resistance. Further, as the corrugated sheet material (2), the flat sheet material may be used.
From (1), a corrugated one having a predetermined substantially sinusoidal or trapezoidal wave is used. In addition, Ni-Cr alloy, Ni-
A Cr-Fe alloy, a Ni-Cr-Al-Fe alloy or the like is also used.

In the present invention, electrode materials (B ₁ , B ₂ ) are arranged in the axial direction at the central portion and the outer peripheral portion of the honeycomb body (H ₁ ) which constitutes the above-mentioned energized heating type honeycomb body (H). Is done. As such an electrode material (B ₁ , B ₂ ), a material having a desired shape may be used according to the structure of the honeycomb body (H ₁ ). For example, as the electrode material (B ₁ , B ₂ ), a wire, a bar, a plate, or the like such as heat-resistant steel or nickel is used. In the present invention, the honeycomb body having a heater function (H), it being used a honeycomb body winding type as shown in Figures 1-2 is fixed in the metal case (C ₁₎ Since it is a normal state, it goes without saying that the metal case (C ₁ ) may be used as an external electrode material (C = B ₂ ). However, as described above, a separate electrode material (B ₂ ) can be used.

The arrangement relationship (energized connection) between the energized and heated honeycomb body (H) of the present invention and the external power supply section (4) is as shown in FIG. 8 when viewed from the entire exhaust gas purifying apparatus (A). In addition, when the honeycomb body (H) is viewed as a center, FIGS.
What is necessary is just to perform as shown in FIG. In the present invention, although not shown, the electrode materials (B ₁ , B ₂ ) are supplied from the external power source (4).
The power supply to the honeycomb may be performed for a limited time by a timer, or a desired setting may be made by measuring the temperature of the honeycomb body or the exhaust gas temperature with a sensor (such as a thermocouple) attached to a desired portion of the honeycomb body. It may be turned on and off by a value, and the mode is not limited in any way. FIGS. 1 and 2 show the on / off switching (7) of the power supply. Also, external power supply (4)
However, it is needless to say that an AC power supply may be used as shown in other embodiments.

A second embodiment of the energized and heated honeycomb body (H) of the present invention will be described with reference to FIG. In the second embodiment shown in FIG. 3, the honeycomb body (H ₁ ) constituting the energized heating type honeycomb body (H) is composed of two honeycomb bodies (H ₁ , H ₂ ). H ₁ , H ₂ ) are arranged in series, and their respective structures are basically the same as those of the single honeycomb body (H ₁ ) shown in FIGS. However,
Each honeycomb body (H _1, H ₂₎ that is varied nonlinearly not linear (concave curve manner) differs width (l) of the. Whether the width (l) of each honeycomb body is changed linearly or non-linearly depends on the manufacturing process of the honeycomb body.

A third embodiment of the honeycomb structure (H) according to the present invention will be described with reference to FIG. In the third embodiment, FIG.
Is substantially the same as that of the second embodiment shown in FIG. ₁ , and two honeycomb bodies (H ₁ , H ₂ ) are arranged in parallel. In the third embodiment, the point that the width of the honeycomb body is changed non-linearly (convex curve) and the common metal case (C ₁ ) of each honeycomb body is connected to the external electrode material (B ₂₎ ) Is different from that of the second embodiment.

A fourth embodiment of the honeycomb structure (H) according to the present invention will be described with reference to FIG. In the fourth embodiment, FIG.
Is substantially the same as that of the third embodiment, except that the width (l) of the honeycomb body is changed in a non-linear manner (stepwise), and an AC power supply is used as the external power supply section (4). They differ in that they do.

A fifth embodiment of the honeycomb structure (H) according to the present invention will be described with reference to FIG. In the fifth embodiment, a honeycomb body (H ₁ ) constituting a current-carrying / heating type honeycomb body (H) is used.
As the one having both ends having an outwardly convex shape,
Thus, the width (l) of the honeycomb body (H ₁ ) in the exhaust gas flow direction is adjusted. The external power supply (4) is an AC power supply. In the fifth embodiment, there is an advantage that the flow velocity distribution of the exhaust gas flow can be adjusted due to the shape of the honeycomb body (H ₁ ).

A sixth embodiment of the honeycomb structure (H) according to the present invention will be described with reference to FIG. In the sixth embodiment, a honeycomb body (H ₁ ) constituting a current-carrying / heating type honeycomb body (H) is used.
A honeycomb body (H ₁ ) having one end face convex outward and the other end face concave.
Is adjusted in the width (l) in the exhaust gas flow direction. In the sixth embodiment as well, the flow velocity distribution of the exhaust gas flow can be adjusted as in the fifth embodiment.

The honeycomb structure (H) according to the present invention comprises:
As described above, it is disposed and used in front of the main catalyst (M) which is a main component of the exhaust gas purification device (A). Next, the main catalyst (M) will be described. The main catalyst (M), which is a main component of the exhaust gas purification device (A), may be a ceramic monolith type or a metal monolith type. These may be manufactured according to a conventional method. For example, a main catalyst supporting base which is a precursor of the main catalyst (M) may be manufactured, and an exhaust gas purifying catalyst may be supported on this. A method for producing the main catalyst-supporting base of a monolith type made of metal will be described below. The honeycomb bodies (H _{1 to} H _n ) constituting the above-mentioned energized and heated honeycomb body (H) are described.
May be manufactured in the manner described below. The method for supporting the catalyst will be described later.

The main catalyst supporting base having a circular cross section shown in FIG. 9 is made of a heat-resistant, thin metal plate made of a flat strip (1) and a corrugated strip (2) so as to abut each other. It is manufactured by stacking and stacking this in a spiral form. Numerous mesh-shaped vent channels (cells) that become exhaust gas routes by winding and laminating (3)
Are automatically formed. The above-mentioned wound type energized and heated honeycomb body (H) is also manufactured by this method. More specifically, it may be manufactured as follows. A flat strip made of a thin steel strip having a thickness of 0.04 mm and a width of 38 mm made of a heat-resistant steel of Fe-Cr 20% -Al 5% -Ce 0.02% is passed between the forming gears to obtain a pitch width (3.0 mm). A corrugated strip with a wave height (1.4 mm). Next, the flat band material and the corrugated band material are stacked one on top of the other, their ends are inserted into the slits of a slit-formed wound forming rod, and are collectively wound and laminated. Reticulated vents (cell density 3
A metal main catalyst supporting body having an outer diameter of 70 mm having a diameter of 70 cpsi may be used.

The main catalyst supporting base having a circular cross section shown in FIG. 10 has a heat-resistant, thin metal plate-like flat band (1) and a corrugated band (2) so as to abut each other. It was manufactured by stacking in a shape.

The main catalyst supporting base having a circular cross section shown in FIG. 11 is made of a heat-resistant, thin metal plate made of a flat strip (1) and a corrugated strip (2) brought into contact with each other. (E), and the desired number of the purifying elements (E) is
And is radially extended from the starting point.

The main catalyst supporting base having a circular cross section shown in FIG. 12 is made into a purification element (E) by abutting a flat plate made of a heat-resistant thin metal plate and a corrugated plate. The purifying elements (E) are stacked in layers so that the outermost surface is a flat strip, and each purifying element is centered on two fixed points (S ₁ , S ₂ ) set on the upper and lower outermost surfaces. (E) is bent in the opposite direction, that is, each purification emergent (E) is bent into a substantially S-shaped curve.

In order to carry a catalyst for purifying exhaust gas such as Pt, Pd, Rh or the like on the main catalyst carrier 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 (r-Al ₂ O ₃ ) powder and alumina sol are applied is applied,
What is necessary is just to heat-process to 0 degreeC. Next, in order to support a catalyst such as a Pt, Pd, Rh catalyst or the like on the catalyst supporting layer formed in this manner, a catalyst component may be supported by a normal method such as impregnation. The main catalyst (M) is manufactured as described above.

The honeycomb structure (H) according to the present invention has the following characteristics.
As shown in FIG. 8, the exhaust gas purifying device (A) is fixed together with the main catalyst (M) in a metal case (C) to manufacture the exhaust gas purifying device (A). Such a metal case (C) is for accommodating and fixing the honeycomb body (H) having the heater function and the main catalyst (M) therein, provided that both ends are open. However, there is no restriction on its shape. As the material of the metal case (C), the same type of heat-resistant steel as that of the main catalyst-carrying base may be used, or a material having higher heat-resistant corrosion resistance may be used. In addition, using a double-structured metal material with a higher heat resistance and corrosion resistance than the inner part, specifically using a ferritic stainless steel for the inner part and an austenitic stainless steel for the outer part Is also good.

[0030]

According to the present invention, a honeycomb body (H) of an energized and heat generating type is provided.
Is disposed upstream of the main catalyst (M) in the metal case (C) as a main component of the exhaust gas purification device. The current-carrying-type honeycomb body (H) has a structure in which the temperature distribution is uniform and sufficient resistance heating is obtained inside. Therefore, in the present invention, since the exhaust gas is heated and heated to a sufficiently high temperature suitable for the catalytic reaction, the exhaust gas is heated uniformly to a sufficiently high temperature suitable for the catalytic reaction during the cold start which is particularly problematic in the exhaust gas treatment. Can significantly improve the exhaust gas purification capacity. Further, in the electrically-heated honeycomb body (H) of the present invention, the constituent members are not locally heated at the time of heating, and it is possible to prevent the deterioration of the vibration resistance (mechanical strength) due to the deterioration of the members. it can. Further, since the honeycomb body (H) itself serves as a heater, it is not necessary to separately prepare and arrange a heater material.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention, in which a part of a current-carrying-type honeycomb body (H) is omitted.

FIG. 2 is a perspective view of the electrically-heated honeycomb body (H) shown in FIG.

FIG. 3 is a cross-sectional view of a second embodiment of the present invention, in which a part of an electrically-heated honeycomb body (H) is omitted.

FIG. 4 is a cross-sectional view of a third embodiment of the present invention, in which a part of a heat-generating honeycomb body (H) is omitted.

FIG. 5 is a cross-sectional view of a fourth embodiment of the present invention, in which a part of a current-carrying and heating type honeycomb body (H) is omitted.

FIG. 6 is a cross-sectional view of a fifth embodiment of the present invention, in which a part of a heat-generating honeycomb body (H) is omitted.

FIG. 7 is a cross-sectional view of a sixth embodiment of the present invention, in which a portion of a current-carrying-type honeycomb body (H) is omitted.

FIG. 8 is a cross-sectional view in which a part of a conventional exhaust gas purification device (A) is omitted.

FIG. 9 is a sectional view of the first embodiment of the main catalyst (M).

FIG. 10 is a sectional view of a second embodiment of the main catalyst (M).

FIG. 11 is a sectional view of a third embodiment of the main catalyst (M).

FIG. 12 is a sectional view of a fourth embodiment of the main catalyst (M).

[Explanation of symbols]

H ......... energization heating type honeycomb body H _1, H _n ...... honeycomb body A ......... exhaust gas purification device F ......... exhaust gas flow direction B _1, B ₂ ......... electrode material C ......... exhaust Metal case of gas purifier C ₁ Metal case of honeycomb body (H ₁ ) M Main catalyst 1 Flat strip 2 Corrugated strip 3 Cell (Mesh-shaped air passage) 4... External power supply 5, 6... Lead wire

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Moraya Awasaka 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (72) Toshiyuki Nishida 1-4-1 Chuo, Wako-shi, Saitama Inside Honda R & D Co., Ltd. (72) Inventor Atsushi Takahashi 1-4-1 Chuo, Wako-shi, Saitama Prefecture Inside Honda R & D Co., Ltd. (56) References JP-A-5-115794 (JP, A) JP-A-4 −284852 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 53/86 B01J 21/00-37/36 F01N 3/20, 3/28

Claims (6)

(57) [Claims] 1. An exhaust gas purifying apparatus comprising an energized heat generating type honeycomb body (H) and a main catalyst disposed at a rear portion of the honeycomb body (H), wherein the energized heat generating type honeycomb body (H) comprises: i) A honeycomb-shaped structure manufactured by stacking a flat metal strip made of a thin metal plate and a corrugated metal strip so as to abut each other, and from the center to the outer periphery of the honeycomb-shaped structure. The honeycomb body (H ₁ ) has a width (1) having a width which gradually decreases in the direction of exhaust gas flow as it goes, and (ii) the honeycomb body (H ₁ ) has a central portion and an outer peripheral portion. An exhaust gas purifying apparatus, comprising: an electrode member connected to an external power supply. 2. A honeycomb body (H ₁₎ is exhaust gas purifying apparatus according to claim 1, which has been divided into a plurality of honeycomb bodies (H ₁ ~H _n). 3. A honeycomb body (H ₁₎ is, the honeycomb body (H ₁₎ exhaust gas purifying apparatus according to claim 1 in which are secured in a metal case for. 4. The exhaust gas purifying apparatus according to claim 1, wherein the width (l) of the honeycomb body (H ₁ ) changes linearly from the center to the outer periphery. 5. The exhaust gas purifying apparatus according to claim 1, wherein the width (l) of the honeycomb body (H ₁ ) changes non-linearly from the center to the outer periphery. 6. The exhaust gas purifying apparatus according to claim 3, wherein the metal case of the honeycomb body (H ₁ ) serves as an outer peripheral electrode material (B ₂ ).