JPH02253825A - Exhaust gas cleaning device - Google Patents

Abstract

PURPOSE:To relieve the deformation force by forming protruding parts in the crest part and the trough part of the wave shape of corrugated strip. CONSTITUTION:In the corrugated strip 11 which is the constituent of a honeycomb core body 1, the protruding parts are formed in a specified distance between each other at least in either of the crest part and the trough part of the wave shape of the corrugated strip 11 in order to absorb and relieve the deformation force due to thermal expansion and thermal stress in the axial direction of the honeycomb core body 1. When the honeycomb core body is made, the protruding parts 2 periodically provided are formed in the direction parallel to the axial direction of honeycomb core body on the side in contact with a plain strip 12. By this method, the deformation force is efficiently absorbed and relieved by nonfixing parts.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention is directed to a method of supporting an exhaust gas purifying catalyst, which is generally inserted in the middle of an exhaust pipe as a means for purifying automobile exhaust gas. The present invention relates to an exhaust gas purification device comprising a metal honeycomb core body.

More specifically, 1. The present invention relates to an exhaust gas purification device of this type used under harsh conditions, which has improved durability against deformation and breakage due to thermal expansion and thermal stress as a metal honeycomb core body. It is related to.

(Prior Art) Conventionally, this type of exhaust gas purification device generally consists of a flat strip made of a heat-resistant thin steel plate and a corrugated strip made by corrugating the thin steel plate, so that the abutting portions of the thin steel plate are corrugated. intussusception,
A honeycomb-like laminate (hereinafter referred to as "honeycomb core") having a large number of mesh-like ventilation holes for exhaust gas passages in the axial direction is produced by winding and stacking this into a PS winding shape, or by stacking it in a layered manner. The honeycomb core body is comprised of a cylindrical metal case with both ends open for loading and fixing the honeycomb core body.

The honeycomb core body and the metal case are designed to withstand thermal expansion and thermal stress caused by the high temperature of the exhaust gas itself and the exothermic reaction between the exhaust gas and the purification catalyst, and to withstand vibrations when the car is running. It is firmly fixed by brazing or welding to ensure durability. It goes without saying that the abutting portions of the flat band material and the corrugated band material constituting the honeycomb core body may be fixed by various methods.

In addition, recently, due to price competition with conventional cordierite ceramic carriers, products that do not use a metal case to load and firmly fix the honeycomb core body, in other words, only a metal honeycomb core body is used to emit exhaust gas. There is a movement to construct a purification system. In this case, since a metal case is not used, manufacturing costs for the metal case, loading and fixing costs for the metal case and the metal honeycomb core body, so-called canning costs, etc. are reduced, resulting in significant cost benefits. Of course.

(Problems to be Solved by the Invention) However, the above-described conventional exhaust gas purification device composed only of a honeycomb core body, or an exhaust gas purification device composed of a honeycomb core body and a metal case,
It cannot withstand long-term use, especially in the axial direction of the honeycomb core body (i.e., the direction of inflow and passage of exhaust gas) under the atmosphere of high temperature of the exhaust gas itself or heat generation due to the catalytic reaction of unburned gas. The deformation force due to thermal expansion and thermal stress that occurs in the honeycomb core body is concentrated near the outer circumference of the honeycomb core body or near the contact surface between the outer circumference surface of the honeycomb core body and the inner wall surface of the metal case. The flat strips and/or corrugated strips constituting the honeycomb core body are severely cracked and damaged near the outer periphery of the honeycomb core body. There is a drawback that peeling of the abutting portion and separation of the bodies occur.

This idea was revised to the idea that it is only necessary to firmly fix the gap between the flat strip material and the corrugated strip material that make up the honeycomb core body, or the outer peripheral surface of the honeycomb core body and the inner wall surface of the metal case. It is a matter of urgency.

The inventors of the present invention have made extensive studies in order to eliminate the drawbacks of the conventional exhaust gas purification devices described above. As a result, among the flat band material and the corrugated band material constituting the honeycomb core body, as the corrugated band material, at least one of the peaks and troughs of the waveform is formed, preferably in the axial direction of the honeycomb core body. The present invention has been completed based on the discovery that the deformation force due to thermal expansion and thermal stress described above can be alleviated very effectively when using a structure in which convex portions are formed at desired intervals in a direction parallel to the above. reached.

[Structure of the invention]

(Means for Solving the Problems) To briefly summarize the present invention, the present invention is directed to a shaft manufactured by stacking a flat strip of thin metal plate and a corrugated strip so as to abut each other. In an exhaust gas purification device comprising a honeycomb core body for supporting an exhaust gas flocculant catalyst having a large number of mesh-like vent passages in a direction, the corrugated sheet-like strip material is arranged so that the crests and troughs of the corrugation are The present invention relates to an exhaust gas spoofing device characterized in that convex portions are formed at a desired interval on at least one side and on the side that abuts the flat strip material.

Hereinafter, the configuration of the present invention will be explained in detail.

In an exhaust gas purification device using a metal honeycomb core body, it is extremely important to have sufficient durability against deformation forces due to thermal expansion and thermal stress (strain).

In other words, this type of exhaust gas removal system is not only exposed to the alternating heat load of the heating and cooling cycle during operation, stop, and restart, but also exposed to a harsh thermal environment while driving, so it has no resistance to heat. The issue of durability is an extremely important issue. In this regard, when considering the situation during driving, the exhaust gas purification device can be Due to the catalytic reaction (exothermic reaction) between the exhaust gas purifying catalyst such as , Rh, etc. and the exhaust gas, the central portion of the honeycomb core body is exposed to a higher temperature than the peripheral portion. Incidentally, the temperature inside this type of exhaust gas purification device is generally between 700 and 80.
The temperature is 0°C, but if a large amount of HC (hydrocarbons) is discharged, the temperature can reach around too much°C.

Looking at the temperature gradient inside the honeycomb core body in more detail, the temperature gradient between the outer circumferential portion of the honeycomb core body and a portion slightly inside the honeycomb core body is significantly larger than the temperature gradient near the central portion. This is further promoted because the outer circumferential surface of the honeycomb core body is in direct contact with the outside air, or because the honeycomb core body is fixed in a cylindrical metal case that is in contact with the outside air.

Therefore, due to this, in an exhaust gas purification device consisting only of a honeycomb core body (of a type that does not use a metal case) or an exhaust gas purification device consisting of a honeycomb core body and a metal case, the honeycomb core body Strong deformation forces (hereinafter also referred to as thermal deformation forces) based on thermal expansion and thermal stress of the constituent members of the honeycomb core body are concentrated near the outer peripheral surface, particularly in the axial direction. This is because, as described above, even if a large temperature difference occurs inside the honeycomb core body, the elongation of the honeycomb core body in the axial direction tends to be the same.

In other words, even if the abutting portions of the structural members (flat strip material and corrugated strip material) near the outer circumferential surface of the honeycomb core body are firmly fixed, they may peel off from each other over time due to the deformation force caused by the heat described above. Otherwise, each component may crack or break.

In conjunction with these peeling, cracking, and damage, the expensive catalyst layer supported on the surface of each component also peels off, leading to a decrease in exhaust gas purification ability. The above-mentioned situation is also the same in an exhaust gas purification device in which the honeycomb core body is loaded and the outermost peripheral surface of the honeycomb core body is firmly fixed to the inner wall surface of the metal case.

Therefore, in order to eliminate or suppress the above-mentioned defects such as peeling, it is essential to take measures to alleviate the deformation force due to thermal expansion and thermal stress in the structure of the honeycomb core body.

Therefore, in the present invention, as a corrugated band material of a heat-resistant thin metal plate which is a member constituting a honeycomb core body,
At least one of the crests and troughs of the waveform of the corrugated strip material,
In addition, a technical configuration is adopted in which a western portion is formed at a desired interval on the side that contacts the flat strip material. That is, when manufacturing a honeycomb core body by winding and laminating a corrugated strip having convex portions and a flat strip as described above according to the present invention C, the corrugated strip and the flat strip have the same shape as described above. They will come into contact with each other at the convex portion, and both strips will be fixed at this location. Therefore, the deformation force due to heat can be absorbed and unified in the non-fixed portions other than the convex portions.

Next, the configuration and embodiments of the present invention will be explained in detail based on the drawings, but it goes without saying that the present invention is not limited to what is shown in the drawings.

In the present invention, the metal honeycomb core body itself is as shown in FIGS. 4 and 8 to 9, and is manufactured by a conventional method.

That is, the honeycomb core body (1) is made of a heat-resistant thin steel plate and has a thickness of 0.03 to 0.1 m, as shown in FIG.
m-sized flat strip material (12) and the flat strip material (]2)
A corrugated strip material (11) which has been corrugated (this has a convex portion on at least one of its peaks and valleys, as will be described later) are stacked together so that they have abutting portions. It is manufactured by stacking the strips and then stacking them together in a spiral shape so that the outermost surface becomes the flat strip material (12). By this winding and lamination, a large number of mesh-like vent passages (13), which serve as passages for exhaust gas, are automatically formed. Moreover, as shown in FIG. 9, the honeycomb core body (1)
A flat strip material (12) and a corrugated strip material (11) (this is
As will be described later, at least one of the peaks and valleys has a convex portion. ) may be stacked so that they are in contact with each other, and then laminated and molded in a layered manner.

1, for example, Fe-Cr2O as the flat strip material (12)
$-Al"d heat-resistant stainless steel, or heat-resistant stainless steel with rare earth added to improve oxidation resistance, with a thickness of 0.04 to 0.1 layer. , and the flat strip material (1) is used as the corrugated strip material (11).
2) is used after being processed into a waveform by passing it through a forming gear.

When stainless steel containing 1 is used for each strip material, whisker-shaped γ-A1203 is precipitated on the surface of the strip material by heat treatment, which is preferable because it firmly supports the exhaust gas purifying catalyst.

In the present invention, the corrugated strip material (11) which is a component of the honeycomb core body (1) is particularly suitable for the honeycomb core body (1).
In order to absorb and alleviate the deformation force due to thermal expansion and thermal stress in the axial direction of 1), at least one of the peaks and troughs of the waveform of the corrugated strip material (11) is made of a honeycomb core body. Convex portions (hereinafter referred to as approximately 6 portions per cycle) are formed at desired intervals in the axial direction (this coincides with the flow direction of exhaust gas) and on the side that contacts the flat strip material (12). be done.

Next, the corrugated strip material (11
), and a corrugated strip material (11) having the periodic convex portions.
A honeycomb core body (1) composed of a flat strip material (12) and a flat strip material (12) will be explained based on the drawings.

Figure 1 shows a corrugated strip (11) with periodic protrusions (2).
FIG.

The periodic convex portions (2) are formed in the peaks and valleys of the corrugated strip material (11) in a direction parallel to the axial direction of the two-force core body when formed into a honeycomb core body, and in a flat plate. They are formed at desired intervals on the side that contacts the shaped strip material (12).

Figure 2 shows the corrugated strip material (
It is a front view of the corrugated strip material (Jl) in which the periodic convex portions (2) formed in the peaks and valleys extend parallel to the axial direction of the honeycomb core body and are discontinuous. It can be seen that the waveform is a repeating trapezoid.

In the present invention, the shape of the periodic convex portions (2) may be arbitrary, for example, as shown in FIGS. 6(a) and 6(b).

There is something like the one shown in (C). Figure 8(a)-(
In c), the cross-sectional shape of the periodic convex portion is a sinusoidal waveform, and in Fig. 6(b)
) shows a waveform in which rectangles are connected, and FIG. 6(C) shows a waveform in which triangles are connected. In addition, Fig. 7 (a
)(b) shows the external shape of the periodic convex portion, FIG. 7(a) shows a spherical shape, and FIG. 7(b) shows a conical shape. , the cross-sectional shape and external shape of the periodic convex portions are not limited to those described above;
For example, there are pyramid-shaped ones. These periodic convex portions may be formed by any method. For example, a flat strip (12) may be passed through a forming gap to form a corrugated strip (12).
11), the periodic protrusions may also be formed at the same time.The height of the periodic protrusions (2) may be set appropriately, but from the viewpoint of workability etc. It may be 1/2 to 1/10 of the wave height (height between peaks and troughs) of the corrugated strip material (11).

In the present invention, the corrugated strips (11) having the above-mentioned periodic convex portions (2) are stacked so that the flat strips (12) have abutting portions, and are collectively spirally formed. A honeycomb core body is manufactured by winding and stacking or stacking in layers. An example of this is shown in FIG.

FIG. 4 shows a corrugated strip (11) having periodic convex portions (2) shown in FIG. 1 and a flat strip (12) shown in FIG.
) is a diagram illustrating a method of manufacturing a honeycomb core body (+) by winding and stacking them in a spiral shape all at once while stacking them. In addition,
Fig. 5 omits a part of the exhaust gas purification device of the present invention in which the honeycomb core body (1) manufactured as shown in Fig. 4 is loaded and fixed in a metal case (3) to be described later. This is a vertical cross section. In FIG. 5, the period of approximately 6f in the axial direction of the honeycomb core body is shown at the peaks of the waveform of the corrugated strip (11).
l! (2) is shown (note that the convex portions of the valleys are not shown because their cross-sectional positions are different).

A corrugated strip (11) and a flat strip (12) are fixed to the honeycomb core body (1) via periodic convex portions (2). In addition, in the present invention, there are no restrictions on the means or method for fixing the two strips, and any means or method known in the art may be adopted.
, 12) are firmly fixed through the periodic protrusions (2), but since the protrusions (2) are periodic, the corrugated strip material (11)
In the peaks and troughs of , regions are formed that are not fixed to the flat strip material (12). Therefore, the corrugated strip material (1
In the non-fixed portions other than the periodic convex portions (2) of 1), it is possible to effectively absorb and alleviate the deformation force due to heat, which is a large load particularly in the axial direction of the honeycomb core body (1).

In the present invention, a winding type exhaust gas purification method as shown in FIG. tW is produced, in which case the following can be used as a corrugated strip (11) with one periodic protrusion (2). That is, the center part of the winding and its vicinity are made of a corrugated strip material (11) that does not have periodic protrusions (2), and the other area (near the outer circumferential surface) is made of a corrugated band material (11) that does not have periodic protrusions (2). It may also be configured by having

The honeycomb core body (1) manufactured using such a corrugated strip material (11) is designed to reduce the deformation force caused by heat that concentrates particularly on the outer circumference of the honeycomb core body (1) and its vicinity. It is possible to effectively absorb and absorb the liquid in the non-fixed portions of the plate-shaped strip (II) other than the periodic convex portions (2). In addition to the above-mentioned advantages, it is possible to relatively increase the amount of the exhaust gas purifying catalyst in this part, which promotes the catalytic reaction (exothermic reaction) with the exhaust gas. The temperature difference with the center can be made more uniform.

In the undeveloped IJJ, the flat strip material (+2) has been explained as being flat in the literal sense, but it absorbs the deformation force due to heat in the axial direction of the honeycomb core body (1),
In order to achieve this, the flat strip material (12) may have a small corrugated shape. may be formed so that the advancing direction of the waveform is parallel to the axial direction of the honeycomb core body (1). In this case, the minute waveform formed on the flat band material also causes the axis of the honeycomb core body to It is possible to absorb and alleviate large deformation forces caused by heat in the direction.

Corrugated strip material (11) having periodic convex portions (2) of the present invention
Honeycomb core body (1) made from flat strip material (12)
) can be used by itself as an exhaust gas purification device a. At that time, a flat band material (12) may be wound around the outermost periphery of the honeycomb core body (1) a desired number of times in place of the metal case. In addition, 4 separate cylindrical metal cases /
\4The cam core body (1) may be loaded and fixed to form an exhaust gas purification device.

In the present invention, the shape of the metal case (3) for loading and fixing the honeycomb core body (1) is not limited in any way as long as both ends of the metal case (3) are open. 7 to 8 show one with a circular cross-section and one with a racetrack-like (elliptic) cross-section; however, the present invention is not limited to this. The exhaust gas converting device may be configured using a metal case having a substantially triangular cross section.The material for the metal case may be the same type of heat-resistant steel as the honeycomb core body, or a heat-resistant steel with high heat and corrosion resistance. Alternatively, a double-structured metal material with the outer part made of a metal material with higher heat and corrosion resistance than the inner part, specifically ferritic stainless steel for the inner part and austenitic stainless steel for the outer part. It is also possible to use clad steel using.

(Example) Fe-20%Cr-5%A4-0.02%Ce (1) A flat strip material made of a thin steel strip of heat-resistant steel with a J size of 0.044 and a layer width of 74.5. It was passed through forming gears and processed into a waveform with a pitch of 4.5 mm and a height of 1.8 ts to obtain a corrugated band material. At that time, as shown in Figure 1, the height of the convex parts at the peaks and valleys of the corrugated strip material is 0.
．． Periodic convex portions were simultaneously formed with five layers, a convexity of convex portions of 1.01, a convex length of 5.0 layers, and an interval between convex portions of 5.0 layers.

The flat strip material and the periodically convex corrugated strip material are wound and laminated as shown in FIG. 4 to produce a honeycomb core body with an outer diameter of 70 mm and having a large number of mesh ventilation holes in the axial direction. was produced.

Next, the honeycomb core body is loaded into a metal case made of heat-resistant steel (JIS G4305 5US310) with an inner diameter of 70 s + m, and both i parts of the honeycomb core body and their neighboring parts (an area 10 mm from the end) are coated with nickel. The honeycomb core body and the metal case were immersed in a slurry of brazing filler metal, dried, and then heat-treated in a vacuum furnace to bond the honeycomb core body and metal case together by brazing.

Next, a catalyst support layer was formed on the exhaust gas purification device manufactured as described above in the following manner. That is, activated alumina (γ-A
J1203) A slurry containing powder and alumina sol was applied and heated to 600°C to form a catalyst supporting layer.

(Performance evaluation) The exhaust gas purification device having the catalyst support layer described above was
When a rapid heating/quenching test of 50 cycles between 0°C and 800°C and a vibration test were conducted, the structural members of the honeycomb core body showed cracks in all parts.

No damage was observed, and no peeling or separation of the abutting portion was observed. Furthermore, the catalyst support layer falls.

No peeling was observed.

〔Effect of the invention〕

In the exhaust gas purification device of the present invention, the NIKAMUKO 7 body part is exposed to particularly severe thermal conditions. , is characterized in that a protrusion (periodic protrusion) is formed at a desired interval on at least one of the peaks and valleys of the waveform and on the side that contacts the flat strip material. . Then, the corrugated band material and the flat band material are fixed to each other via the periodic convex portions to form a honeycomb core body.

Therefore, the honeycomb core body of the present invention effectively absorbs the deformation force due to heat, especially the deformation force due to large heat applied in the axial direction of the honeycomb core body, in the non-fixed portions other than the periodic convex portions. It can be relaxed.

This is done in order to improve the ability to follow the thermal expansion and contraction of the constituent members of the honeycomb core body, particularly on the outer circumferential surface of the honeycomb core body where deformation force due to heat is concentrated, and in the vicinity thereof. cracks, damage,
Also, it is possible to prevent the contact portion between the members from separating.

Also, the catalyst supporting layer formed on the wall surface of the honeycomb core body for supporting the exhaust gas purifying catalyst is effectively prevented from falling and peeling off.

Furthermore, the flow of exhaust gas is disturbed inside the honeycomb core body due to the gap between the part of the periodic convex part that contacts the flat strip material (fixed part) and the part that does not contact (non-fixed part).
1! (agitation effect), thereby increasing the contact between the exhaust gas and the catalyst layer.

Therefore, the exhaust gas purification device of the present invention can be used safely for a long period of time, and can maintain high purification ability.

[Brief explanation of drawings]

FIG. 1 is a partial perspective view of a corrugated band having periodic convex portions, and FIG. 2 is a partial front view as seen from the direction of arrow A in FIG. FIG. 3 is a partial plan view of a flat band material that is a component of the honeycomb core body. FIG. 4 is a diagram illustrating a process of manufacturing a honeycomb core body from a corrugated strip having periodic convex portions and a flat strip. FIG. 5 is a partially omitted longitudinal cross-sectional view of the exhaust gas purification device of the present invention. FIGS. 6(a), (b), and (c) are views corresponding to the f52 diagram showing other cross-sectional shapes of periodic convex portions, and FIG. 6(a) shows a sine waveform; 6(b) shows a waveform in which squares are connected, and FIG. 6(c) shows a waveform in which triangles are connected. FIGS. 7(a) and (b) show the external appearance of periodic convex portions formed on a corrugated strip, and FIG. 7(a) shows a corrugated sheet having spherical convex portions. FIG. 7(b) shows a partial perspective view of a corrugated band having a conical convex portion. FIG. 8 is a partially omitted front view of a honeycomb core body manufactured by winding and laminating a corrugated band material having periodic convex portions and a flat band material, fixed in a metal case. FIG. 9 is a partially omitted front view of a honeycomb core body manufactured by stacking corrugated strips having periodic convex portions and flat strips in a layered manner and fixed in a metal case. l...Own...Honeycomb core body 11...Flat strip material 12...Corrugated strip material 13...Mesh ventilation hole passage 2...・Periodic convex portion 3...Metal case Fig. 8

Claims (1)

[Scope of Claims] 1. Exhaust gas having a large number of mesh-like ventilation holes in the axial direction, which is manufactured by stacking a flat strip and a corrugated strip of thin metal plates so that they are in contact with each other. In an exhaust gas purification device consisting of a honeycomb core body for supporting a purification catalyst, the corrugated strip material is arranged in at least one of the peaks and troughs of the corrugation and on the side that contacts the flat strip material. An exhaust gas purification device characterized in that convex portions are formed at desired intervals. 2. The exhaust gas purification device according to claim 1, wherein the convex portions are formed intermittently in the axial direction of the honeycomb core body. 3. The exhaust gas purification device according to claim 1, wherein the convex portion is formed to extend parallel to the axial direction of the honeycomb core body. 4. The cross-sectional shape of the convex part is sinusoidal, triangular,
2. The exhaust gas purification device according to claim 1, wherein the exhaust gas purification device has a waveform selected from trapezoidal and rectangular waveforms. 5. The exhaust gas purification device according to claim 1, wherein the convex portion is a spherical, conical, or pyramidal protrusion. 6. The exhaust gas purification device according to claim 1, wherein the flat band material and the corrugated band material are fixed to each other via a convex portion. 7. Claim 1, wherein the honeycomb core body is manufactured by stacking a flat strip material and a corrugated strip material so that they are in contact with each other, and then winding them in a spiral shape and laminating them. The exhaust gas purification device described in . 8. The corrugated strip material constituting the honeycomb core body does not have a convex portion near the center of the winding, but has convex portions in other parts, according to claim 7. Exhaust gas purification device. 9. The exhaust gas purification device according to claim 1, wherein the honeycomb core body is manufactured by stacking flat strips and corrugated strips in a layered manner so as to abut each other. 10. The exhaust gas purification device according to claim 1, wherein the honeycomb core body is fixed within a metal case. 11. The exhaust gas purification device according to claim 10, wherein the metal case has a circular cross section. 12. The exhaust gas purification device according to claim 10, wherein the metal case has a racetrack shape in cross section.