JPH0780326A - Metal honeycomb body - Google Patents

Abstract

PURPOSE:To improve the purifying power for exhaust gas and to prevent the conventional scooping phenomenon in a metal honeycomb body by providing small sections into which honeycomb bodies are divided by notch parts successively in the form of a meander and arranging the notch parts of the honeycomb body so that the notch parts may not coincide with those of a honeycomb body provided with them respectively before and after this honeycomb body. CONSTITUTION:In a metal honeycomb body H whose plate-shaped belt materials 1 and corrugated belt materials 2 are piled up and on which a purification catalyst for exhaust gas is carried, the flow of exhaust gas passed through notch parts S1, S2 of the 1st metal honeycomb body H1 impinges the front of the 2nd metal honeycomb body H2 to turn into turbulence, and also it is forcibly mixed with the other flow of exhaust gas in a clearance part D and flows into the 2nd metal honeycomb body H2 of the next stage and is purified. Through this process, the total purification rate for exhaust gas is kept high, and also the internal temp. of the 1st and the 2nd metal honeycomb bodies H1, H2 are made more uniform and, by the uniformizing, the generation of thermal stress accompanying the uniformizing is prevented.

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 device installed in the middle of an exhaust system as a means for purifying exhaust gas of an automobile, and more particularly to supporting an exhaust gas purifying catalyst which is a main component thereof. Regarding the metal honeycomb body of.

More specifically, the present invention promotes turbulence of exhaust gas to improve purification efficiency, and makes the temperature distribution inside the metal honeycomb body more uniform to prevent scoping as well as to prevent The present invention relates to an exhaust gas purifying metal honeycomb body capable of effectively preventing damage to constituent members.

[0003]

2. Description of the Related Art This type of exhaust gas purifying catalyst (for example, P
As a metal carrier for supporting t, Rh, Pd, etc.), increase the amount of catalyst supported per unit volume (effective contact between exhaust gas per unit volume and purification catalyst). In consideration of such things as maximizing the area), reducing back pressure (exhaust resistance), and reducing the weight of the metal supporting base as much as possible, it is possible to use heat-resistant and thin-walled metal plates. A metal carrier matrix (in the present invention, referred to as a metal honeycomb body) having a honeycomb structure by stacking a flat band member and a corrugated plate member having a predetermined width so as to abut each other is well known. Has been.

The above-mentioned metal honeycomb body has, for example,
A flat strip made of heat-resistant thin steel plate with a thickness of 1 mm or less (preferably 50 μm or less) and a corrugated strip made by corrugating the thin steel plate are stacked so as to have mutual contact portions. Then, this is collectively wound into a spiral shape to form a honeycomb body having a honeycomb structure having a large number of mesh-like vent holes (cells) for exhaust gas passages in the axial direction. Then, the wound and laminated metal honeycomb bodies are housed in a cylindrical metal case having both ends opened as needed and fixed to each other to form an exhaust gas purifying device having a vibration-proof structure.

There are various types of metal honeycomb bodies other than the above-mentioned wound type, depending on the difference in the method of manufacturing the metal honeycomb body from the flat band material and the corrugated plate material. For example, a layered type in which both strips are layered in layers, and in addition to this, Japanese Patent Laid-Open Nos.
3051, JP 1-218637, JP-A 3-502660, JP
No. 4-227855 and the like disclose metal honeycomb bodies of radial type, S-shaped type, tongue-shaped type, X-wrap (swastoid) type and the like.

As is well known, since this type of exhaust gas purifying apparatus is used under severe thermal environment conditions such as an exhaust gas system, the metal honeycomb body, which is a main component thereof, has a high temperature resistance. Touchability (gas corrosion resistance in exhaust gas system around 1000 ° C), resistance to cold heat (durability under repeated thermal cycles of low temperature and high temperature), high temperature oxidation resistance (durability against abnormal oxidation at high temperature) It is preferable to use a heat-resistant steel foil material having excellent physical properties such as). As a material for manufacturing this kind of honeycomb carrier, Fe-Cr-Al system (20C
(r-5Al series) heat-resistant steel rolled into a foil with a thickness of several tens of μm is used. In addition, a small amount of rare earth element component (REM) is added to the heat resistant steel in order to improve high temperature oxidation resistance.
The one with added is also used.

In addition, since the exhaust gas purifying device is used under severe vibration, the metal honeycomb body, which is a main component of the exhaust gas purifying device, is one of the abutting portions of the strip materials constituting the honeycomb body. A part or the whole is fixed by welding, brazing, mechanical joining means or the like to have a vibration resistant structure.

As described above, in the metal honeycomb body which is a main constituent element of the exhaust gas purifying apparatus, in order to improve its durability, from the surface of the material (development of the material) or the surface of the vibration-proof structure (fixing means). Efforts have been made, but they are not sufficient. In particular, under the severe thermal environment conditions described above, the non-uniform temperature distribution inside the metal honeycomb body (because the exhaust gas flow velocity distribution in the central portion of the metal honeycomb body and in the vicinity thereof is faster than that in other portions, Due to the exothermic reaction with, the site is exposed to a higher temperature than other sites.), And there is a disadvantage that the central part of the metal honeycomb body and the vicinity thereof are scoped. Such a scoping phenomenon occurs along with a cooling / heating cycle of the internal combustion engine such as start, operation, stop, etc., and severe vibration is added to this, so that the durability of the metal honeycomb body is greatly impaired. . For example, the durability of the metal honeycomb body is deteriorated, such as the peeling of the welded portion or the brazed portion of the flat plate and the corrugated plate forming the metal honeycomb body and the damage of the flat plate and the corrugated plate due to the peeling.

Various means have been proposed as means for solving the above-mentioned drawbacks caused by the uneven temperature distribution inside the metal honeycomb body. For example, as a method of making the exhaust gas flow turbulent inside the metal honeycomb body to make the temperature distribution inside the honeycomb body uniform and to improve the purification efficiency, either one of a flat strip and a corrugated strip is used. To
There is a honeycomb body in which one or more stripes (holes) are provided in the longitudinal direction of the strip material at a predetermined interval in the flow direction of exhaust gas (Japanese Patent Publication No. 62-4531).
issue). The above-mentioned ones are effective in that the exhaust gas is turbulent in the stripe portion, and the expansion due to the thermal stress in the axial direction of the honeycomb body is absorbed and alleviated. However, since the strip material having the striped portion formed on either the flat strip material or the corrugated strip material is used, the strip portion is further provided in terms of firm fixation with other strip materials. For example, the amount of catalyst carried decreases.
I have another problem.

Many other turbulent flow imparting means have been proposed, such as those in which a small hole is formed in the strip or a small projection having a hole in the top is provided. (Actual Kokoku Sho 52-19047, Actual Kaisho Sho 63-258647, Japanese Unexamined Patent Publication Sho 6
3-258647), its effect is not sufficient.

[0011]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention The present invention has been devised to solve the above-mentioned problems of the conventional metal honeycomb body. In particular, the present invention comprises (1) a metal honeycomb body not composed of a single body, and composed of two or more of the same or different types, and (2) in each of the two or more metal honeycomb bodies, The two or more notches having a predetermined width are provided in a predetermined manner (in each metal honeycomb body, the notches are formed in such a manner that regions (subsections) sectioned by the notches are arranged in a zigzag manner. (3) When a configuration is adopted in which two or more metal honeycomb bodies are arranged in such a manner that most of the cut portions provided in each of the metal honeycomb bodies do not overlap (do not overlap). It is based on the finding that the exhaust gas flow is effectively turbulent inside the metal honeycomb body.

Further, although the amount of catalyst carried decreases due to the formation of the notch, the above-mentioned turbulent effect maintains the exhaust gas purifying ability. In other words, the amount of catalyst carried does not decrease. It is based on the finding that they are offset and do not pose a problem. Furthermore, each metal honeycomb body is based on the finding that high strength can be maintained even if the above-mentioned cut portion is provided, in other words, it can exhibit excellent durability for a long period of time. is there. According to the present invention, since the exhaust gas flow is effectively turbulent inside the metal honeycomb body, the exhaust gas purification performance is improved, and the main configuration of the exhaust gas purification device in which the conventional scoping reduction is improved. An element, a metal honeycomb body, is provided.

[0013]

The present invention will be described in brief. The present invention is directed to an exhaust gas purifying catalyst produced by stacking a flat metal strip and a corrugated metal strip. In the metal honeycomb body (H) for supporting, the metal honeycomb body (H) is (i) two or more metal honeycomb bodies (H =
H ₁ + H ₂ ...... H _n , n ≧ 2), and (ii) each metal honeycomb body has two or more notches (S) having a desired width (w) (S = S ₁ + S ₂ ...... S). _n , n ≧ 2), and the subsections of the respective metal honeycomb bodies that are divided by the notches (S ₁ , S ₂ , ..., S _n ) are divided so as to be connected in a meandering shape. iii) Each metal honeycomb body is arranged so that the notch (S) of the metal honeycomb body does not coincide with the notch of the metal honeycomb body arranged at the front and rear (including the case of only the front side or only the rear side). And a metal honeycomb body.

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

FIG. 1 is a perspective view of a metal honeycomb body (H) according to the first embodiment of the present invention. As shown in the figure, the metal honeycomb body (H) of the present invention is composed of two metal honeycomb bodies (H = H ₁ + H ₂ ). Each metal honeycomb body (H ₁ , H ₂ ) is a laminated type in which flat plate-shaped strips (1) and corrugated plate-shaped strips (2) are alternately laminated in a layered manner. By laminating both strips, a mesh-like vent hole (cell) (3) which becomes a passage for exhaust gas is automatically formed. It should be noted that FIG. 1 shows only a part of the laminated structure for simplifying the drawing. In the present invention, the metal honeycomb body (H) is composed of two or more (H = H ₁
+ H ₂ ... H _n , n represents an integer of 2 or more. )

The first metal honeycomb body (H₁) Is the width
Two notches (S) in (w) (S = S₁+ S₂)
It has been burned. The notch (S = S₁+ S₂)
Tal honeycomb body (H₁) Is provided in the cut portion
The small area (H₁₁, H
₁₂, H ₁₃) Is H₁₁→ H₁₂→ H₁₃Are connected in a meandering order
It is of the embodiment described above. In other words, metal honeycomb body
(H₁) Is H₁₁, H₁₂, H₁₃Spelled in small areas
It is arranged in a folded shape. Like this
The advantage of providing the notch is that the metal honeycomb body (H₁)
From the viewpoint of overall strength and stability of
It In the present invention, the number of notches (S) is different.
Anything you want (S = S₁+ S₂…… S_n, N is arbitrary
Indicates an integer).

Similarly, the second metal honeycomb body (H ₂ ) has _two notches (S) as shown in the drawing.
= S ₁ + S ₂ ). However, in FIG.
₂ of S ₂ is shadowed by H _1. In the present invention, a cut portion (S = S ₁ + S) having a predetermined width (w) and a predetermined length (l) in the first to second metal honeycomb bodies (H _{1 to} H ₂ ).
_The method of providing ₂ ) may be arbitrary. For example, a flat strip (1) is used which has been previously processed by a predetermined method so that the cut portion is formed when the corrugated strip (2) is laminated, or both strips which have not been processed are used. The (1 and 2) may be alternately laminated and then the cut portion may be formed by a cutting tool, an electric discharge machine, a laser machine, or the like. In the present invention, the predetermined width (w) is set appropriately, but both strips (1,
When viewed from the size of the cell (3) formed by 2), it is preferably within 5 times the average diameter of the cell from the viewpoint of the effect of imparting turbulence to the exhaust gas and the purifying ability. The average diameter of the cells may mean that the cells formed by both strips (1, 2) do not have a single diameter or have a uniform diameter between cells. Therefore, it is an averaged meaning.

The metal honeycomb body of the present invention (H = H ₁ + H
_{In 2} ), the next major feature is the arrangement method of the metal honeycomb bodies (H ₁ , H ₂ ). As shown, the first metallic honeycomb body (H ₁₎ and the second metallic honeycomb body (H ₂₎ is part cuts formed in each of the (H ₁ S = the S ₁ + S _2, H ₂ S = S ₁ + S ₂₎ when the attention, of S ₁ and H ₂ of the H ₁ S ₂ as well as H ₁ S
₂ and S _{2 of} H ₂ are arranged so as to be orthogonal to each other.
Needless to say, when the cut portions (S = S ₁ + S ₂ ) provided in each of H ₁ and H ₂ overlap with each other, the exhaust gas passing through the cut portions is transferred to the metal honeycomb body. The chances of contact with the supported catalyst are reduced, and the purification rate deteriorates. Therefore, in the present invention, such a disposition relationship of each metal honeycomb body is eliminated. That is, in the present invention, each metal honeycomb body (H
₁ and H ₂ ) are arranged such that the cut portions (S) formed in each metal honeycomb body do not match (are not overlapped) between the metal honeycomb bodies. It is characterized by that. In the present invention, the meaning that the cut portions (S) do not match between the metal honeycomb bodies means that the cut portions (S) do not match in most regions (do not overlap). Is. In the embodiment of FIG. 1, S ₂ of S ₁ and H ₂ of an H ₁ is in an orthogonal relationship,
Both of them overlap (overlap) at orthogonal positions, but such an arrangement mode is not excluded in the present invention.

In the present invention, each metal honeycomb body (H
The distance (d) between the gaps (D) of ( ₁ , H ₂ ) may be set as desired. The interval (d) does not have to be provided in particular, and when it is provided, it may be an optimal gap from the viewpoint of the turbulent flow imparting effect and the exhaust gas purifying ability. Generally, a gap (d) of 10 mm or less is set.

In the metal honeycomb body (H = H ₁ + H ₂ ) of the present invention shown in FIG. 1, the exhaust gas flow passing through the cut portion (S = S ₁ + S ₂ ) of the first metal honeycomb body (H ₁ ). Collide with the front surface of the second metal honeycomb body (H ₂ ) and become turbulent, and are forcibly mixed with other exhaust gas flow in the gap (D), and the second metal honeycomb body (H It will flow into the inside of ₂ ) and be purified.
Through this process, the overall purification rate of exhaust gas is kept high and the metal honeycomb body (H = H ₁ + H
_Since the internal temperature of ₂ ) is more uniform, the scoping phenomenon does not occur unlike in the past. Further, since the internal temperature of the metal honeycomb body is made more uniform, the occurrence of thermal stress due to the nonuniformity is prevented, and thus the durability of the metal honeycomb body is improved.

FIG. 2 is a perspective view of the metal honeycomb body (H) according to the second embodiment of the present invention. The metal honeycomb body (H) of the second embodiment is basically the same as that of the first embodiment, but n metal honeycomb bodies (H ₁ + H ₂ +
... H _n , n ≧ 2) is the only difference. Of course, in each of the metal honeycomb bodies, the formed notches (S = S ₁ + S ₂ ) have the most notches between the metal honeycomb bodies between the metal honeycomb bodies as in the first embodiment. Are arranged so as not to coincide with each other.

FIG. 3 is a perspective view of the metal honeycomb body (H) according to the third embodiment of the present invention. The metal honeycomb body (H) of the third embodiment is basically the same as that of the first embodiment, but two wound type metal honeycomb bodies (H = H ₁ + H ₂ ) each having a circular cross section. ), And three cuts (S = S ₁ + S ₂ ) on each metal honeycomb body.
The difference is that + S ₃ ) is formed.

In the present invention, although not shown, the structure of the two or more metal honeycomb bodies forming the metal honeycomb body (H) is not limited to the above-mentioned laminated type or wound type. For example, the radial type known in the art, S
Character-shaped type, tongue-shaped type, X-wrap (swastika) type and the like are used. Further, it goes without saying that as these various types of metal honeycomb bodies, the same kind or different kinds may be used.
When two or more types of metal honeycomb bodies are used as the two or more metal honeycomb bodies, the exhaust gas flow is more nonuniform than that of the same type.

In the present invention, the flat plate-shaped strip material (1) used for producing the above-mentioned various types of metal honeycomb bodies is a strip used for producing a normal metal monolith type honeycomb body. Materials such as chrome steel (chrome 13-25%), Fe-Cr 20% -Al 5%
A band material having a thickness of 0.04 mm to 0.1 mm, such as a heat resistant stainless steel or a heat resistant stainless steel to which a rare earth element is added to improve the high temperature oxidation resistance, is used. As the corrugated strip (2), the flat strip (1) is used.
Is used which is corrugated so as to have a predetermined substantially sine wave or substantially trapezoidal wave. In addition, flat strip (1)
The corrugated strip material (2) and the corrugated strip material (2) may have different plate thicknesses or different materials. In particular, a flat strip (1) and a corrugated strip (2) containing Al,
Or heat-treating the one with Al layer on its surface,
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 composed of Pt, Pd, R
This is preferable because the washcoat layer for supporting the exhaust gas purifying catalyst such as h can be firmly held.

The above-mentioned various types of metal honeycomb bodies (H) of the present invention are the main constituent elements of the exhaust gas purifying apparatus as described above. Generally, an exhaust gas purifying apparatus is manufactured by housing the metal honeycomb body (H) in a metal casing and fixing it. The above-mentioned metal casing is for accommodating and fixing the metal honeycomb body (H) inside, and has any opening as long as it has the same cross-sectional shape as the metal honeycomb body (H). It is not restricted. That is, not only a circular shape, but also a race track, an ellipse, a polygonal shape, or another cross-section may be used. As the material of the metal casing described above,
Band materials (1, 2) constituting the metal honeycomb body (H)
The same type of heat resistant steel may be used, or a double structure with more excellent heat and corrosion resistance, specifically one that uses ferritic stainless steel for the inner part and austenitic stainless steel for the outer part You may use.

[0026]

The metal honeycomb body (H) for carrying the exhaust gas purifying catalyst of the present invention is not constituted by a single body as in the conventional case, but two or more metal honeycomb bodies (H = H). ₁ + H ₂ ... H _n , n ≧ 2), and each metal honeycomb body is formed with a cut portion for promoting turbulence of the exhaust gas flow, and each metal honeycomb body is formed with the cut portion. It is arranged and configured in an optimum positional relationship so as to promote turbulent flow due to. Therefore, in the metal honeycomb body of the present invention, since the exhaust gas flow is efficiently turbulent, the internal temperature of each metal honeycomb body is made more uniform, and an excellent exhaust gas purifying ability is achieved. Further, since the generation of thermal stress due to the nonuniform internal temperature is suppressed by making the internal temperature uniform, the scoping phenomenon is prevented or the members (flat plate member and corrugated plate member) forming the metal honeycomb body are prevented. It is possible to effectively prevent the contact members from being separated from each other and buckling or damage of these members.

[Brief description of drawings]

FIG. 1 is a perspective view of a metal honeycomb body of a first embodiment of the present invention.

FIG. 2 is a perspective view of a metal honeycomb body of a second embodiment of the present invention.

FIG. 3 is a perspective view of a metal honeycomb body of a third embodiment of the present invention.

[Explanation of symbols]

H, H ₁ …… H _n ………… Metal honeycomb body S, S ₁ …… S _n ………… Incision portion D ………… Gap portion d ………… (Gap portion) spacing w ………… (Incision portion) ) Width ………… Length (of the cut portion) 1 ………… Flat plate strip 2 ………… Corrugated strip 3 ………… Reticulated vent passage (cell)

Claims (6)

[Claims] 1. A metal honeycomb body (H) for carrying a catalyst for purifying exhaust gas, which is manufactured by stacking flat plate-shaped strips made of thin metal plates and corrugated strip-shaped strips. (H) is (i) two or more metal honeycomb bodies (H = H ₁ + H ₂ ...... H
_n , n ≧ 2), and (ii) each metal honeycomb body has two or more cut portions (S) having a desired width (w) (S = S ₁ + S ₂ ... S _n , n ≧ 2).
In addition to having each notch (S ₁ , S ₂ , ...
S _n ), the sub-sections of each metal honeycomb body are subdivided so as to be connected in a meandering manner, and (iii) each metal honeycomb body has a notch (S) in front and back (S). The metal honeycomb body is arranged so as not to coincide with the cut portion of the metal honeycomb body arranged only on the front side or only on the rear side. 2. The width (w) of the notch (S) is within 5 times the diameter of the mesh-like ventilation passages (cells) formed when the flat strip and the corrugated strip are stacked. The metal honeycomb body according to claim 1. 3. A metal honeycomb body (H ₁ , H _2, ... H)
The metal honeycomb body according to claim 1, wherein n ₁ and n 2) are filled and fixed in a metal casing made of metal. 4. A metal honeycomb body (H ₁ , H _2, ... H)
2. The metal honeycomb carrier according to claim 1, wherein _n , n ≧ 2) is a laminated type, a wound type, a radial type, an S-shaped type, a tongue-shaped type, and an X-wrap type. 5. A metal honeycomb body (H ₁ , H _2, ... H)
The metal honeycomb body according to claim 4, wherein n ₁ and n 2) are composed of different types. 6. A metal honeycomb body (H ₁ , H ₂ ... H)
The metal honeycomb body according to claim 1, wherein _n ) is provided with a gap or is provided without a gap.