JPH0610133Y2 - Exhaust gas purification device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial field of application) The present invention supports an exhaust gas purifying catalyst, which is generally provided in the middle of an exhaust pipe as a means for purifying exhaust gas of an automobile. The present invention relates to an exhaust gas purification device including a metallic honeycomb core body and a tubular metal case. More specifically, the present invention relates to an exhaust gas purifying apparatus of this type used under severe conditions, and in particular, an exhaust gas that can effectively prevent separation between constituent members and cracking or damage of the members due to thermal stress. The present invention relates to a gas purification device.

(Prior Art) Conventionally, an exhaust gas purifying apparatus of this type has a contact portion between a flat strip made of a heat-resistant thin steel plate and a corrugated strip made by corrugating the thin steel plate. As described above, the honeycomb-shaped laminated body (hereinafter, referred to as a honeycomb core body) having a large number of mesh-like air vent passages for exhaust gas passages, which is manufactured by stacking and stacking them in a spiral shape in a lump, is manufactured. ) And a cylindrical metal case with both ends open.

The honeycomb core body and the metal case are heated by heat transferred from the high-temperature exhaust gas itself and an exothermic reaction between the exhaust gas and the purification catalyst, and thermal stress and heat in a high-temperature atmosphere accompanying this heating. The honeycomb core body and the metal case are firmly fixed to each other by brazing or the like over the entire abutting surface so as to withstand deformation and vibration during traveling of the automobile. Therefore, the heat of the honeycomb core body is quickly transferred to the metal case to be dissipated, and as a result, the thermal stress becomes larger near the outer peripheral surface of the honeycomb core body. It goes without saying that the abutting portions of the flat plate-shaped band member and the corrugated plate-shaped band member that form the honeycomb core body are fixed by various methods.

(Problems to be Solved by the Invention) However, the conventional exhaust gas purifying apparatus composed of the honeycomb core body and the metal case described above cannot endure long-term use. In particular, in the axial direction of the honeycomb core body (that is, the exhaust gas flow direction), due to thermal stress and thermal deformation under the above-mentioned high temperature atmosphere, the outermost peripheral surface and the inner wall surface of the metal case are greatly separated, Also, peeling of the flat plate and / or the corrugated plate forming the honeycomb core body,
It has the drawback of being severely cracked and damaged.

This is a correction to the idea that the honeycomb core body and the metal case may simply be firmly fixed to each other.
The inventor has found that the outermost peripheral surface of the honeycomb core body is separated from the inner wall surface of the metal case, the flat strip material and the corrugated strip material forming the honeycomb core body are separated from each other, and the strip material is cracked. We have diligently studied measures to prevent damage over a long period of time.

As a result, instead of forming a single honeycomb core body, a plurality of honeycomb core bodies are opened at both ends, and are arranged apart from each other in a metal case having a diameter-expanded portion at a key portion, and the outer peripheral surface of the honeycomb core body is formed. When the one end of each honeycomb core body is fixed and the other end is brought into contact with the contact surface between the inner wall surface of the metal case and the non-expanded portion, the end on the contact side is axially moved. Since it can be expanded and contracted, deformation due to thermal expansion can be dispersed and relaxed extremely effectively, and a separating portion formed by separating a plurality of honeycomb core bodies, and a diameter expansion portion of the honeycomb core body and the metal case. It is possible that the voids formed in the chamber can improve the purification efficiency by giving the effect of causing turbulence in the flow of the exhaust gas, and can make the temperature distribution in the device more uniform (this is because the honeycomb core body has an outer peripheral surface with respect to it). Before becoming a heat insulation space It is further promoted by the voids), and the outer peripheral surface of each honeycomb core body is fixed to the inner wall surface of the metal case at one end and abuts at the other end, thereby reducing the vibration resistance. I came to complete the idea.

[Constitution of device]

(Means for Solving Problems) The present invention will be described in brief. The present invention is directed to an axial direction produced by stacking flat metal strips of thin metal plates and corrugated metal strips so as to abut each other. A plurality of honeycomb core bodies having a large number of mesh-like air vent passages at both ends, and a portion that is in contact with the outer peripheral surface in the vicinity of both end portions of each honeycomb core body and a portion that has other diameters In an exhaust gas purifying apparatus for carrying an exhaust gas purifying catalyst, which is fixedly separated in a metal case consisting of, the honeycomb core body and the metal case are fixed to each other at both end portions of the honeycomb core body. The present invention relates to an exhaust gas purifying device, characterized in that, of the contact surfaces between the outer peripheral surface in the vicinity and the inner wall surface of the metal case, one end is fixed and the other end is contacted.

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

As described above, in the conventional exhaust gas purifying apparatus, generally, one honeycomb core body is packed in a tubular metal case having open both ends, and the outer peripheral surface of the honeycomb core body and the inner wall surface of the metal case are firmly fixed to each other. Manufactured. However, the exhaust gas purifying device having such a structure cannot endure long-term use.

In particular, the exhaust gas purification device is susceptible to deformation (distortion) due to thermal stress, which is a major factor that reduces durability.

That is, it goes without saying that the exhaust gas purifying device undergoes large thermal stress and thermal deformation due to the heating / cooling cycle depending on the start / stop and load level. .

In this respect, when considering the situation during traveling, the exhaust gas purification device shows that the exhaust gas flow rate distribution is different (the flow rate at the central portion is higher than that at the peripheral portion), and the exhaust gas purification apparatus carried on the surface portion of the honeycomb core body. The central portion of the honeycomb core body is exposed to a higher temperature than the peripheral portion due to the contact reaction (exothermic reaction) between the exhaust catalyst (catalyst such as Pt, Pd, Rh) and the exhaust gas.

When the temperature gradient inside the above-mentioned honeycomb core body is examined in more detail, the temperature gradient between the outer peripheral surface of the honeycomb core body and a portion slightly inward thereof is significantly larger than the temperature gradient in the same distance in the vicinity of the central portion. . This is because the outer peripheral surface of the honeycomb core body is fixed to the tubular metal case that is in contact with the outside air, so that the heat transferred from the honeycomb core body through the fixed contact surface with the metal case to the outside. Since the heat is dissipated, it is further promoted.

Therefore, due to this, strain due to large thermal stress occurs, and even if the outermost peripheral surface of the honeycomb core body is fixed to the inner wall surface of the metal case by brazing, etc. And both try to peel off.

Similarly, the honeycomb core body is formed between the outer peripheral surface of the honeycomb core body which is fixed to the inner wall surface of the metal case by brazing or the like by the deforming force (strain) based on the above-mentioned thermal stress and the portion slightly inside thereof. The contact between the flat strip and the corrugated strip is peeled off, and the strip is cracked or damaged.

In order to suppress or prevent the above-mentioned peeling and the like, it is necessary to take measures to alleviate the deforming force (strain) based on the thermal stress, especially in the vicinity of the outer peripheral surface of the honeycomb core body.

For this reason, in the present invention, a plurality of honeycomb core bodies are arranged with a desired width apart in a metal case having both ends opened and a large-diameter portion in a key portion, and the two are bonded by brazing or the like. Adopt a technical structure of sticking. In the present invention, as the above-mentioned metal case, a metal case having a diameter-expanded portion at a portion excluding the portions in the vicinity of both ends of each of the honeycomb core bodies to be fitted and fixed is used. In the present invention, the metal case is not limited to the one having the above-described expanded diameter portion, and the expanded case having the above-described structure and having the expanded diameter portion extending over the central portion except both ends of the metal case. Can also be used.

In the present invention, the above-mentioned fixing of both, that is, the fixing of the respective honeycomb core bodies to the inner wall surface of the metal case having the expanded diameter portion is performed by fixing the outer peripheral surface of one end of each honeycomb core body to the non-expanding state of the metal case. It is done so that it adheres to the inner wall surface of the diameter part. On the other hand, the outer peripheral surface of the other end of the honeycomb core body is brought into contact with the inner wall surface of the non-expanded portion of the metal case (not fixed by brazing or the like) to form a non-fixed portion. It can be expanded and contracted in the direction.

In the exhaust gas purifying apparatus having the above-described structure of the present invention, each honeycomb core body is arranged in a metal case having a widened portion at a predetermined width with a predetermined width apart, and an outer peripheral surface of the honeycomb core body. Has one end fixed to the inner wall surface of the metal case, but the other end only abuts, so that it effectively absorbs axial deformation due to large thermal stress particularly in the vicinity of the outer peripheral portion of the honeycomb core body. be able to. Further, since the outer peripheral surface of the honeycomb core body in the vicinity of the separated portion is fixed or abutted on the inner wall surface of the metal case, the honeycomb core body has durability against vibration during traveling of the automobile. Further, the separated portions formed between the honeycomb core bodies can provide an effect of causing turbulence in the flow of the exhaust gas, thereby making the exhaust gas purification performance more uniform in each portion of the honeycomb core body. be able to. In addition, the voids formed between the outer peripheral surface of each honeycomb core body and the expanded diameter portion of the metal case perform adiabatic heat retention effect and make the temperature distribution in the metal case more uniform, so thermal stress deformation It is possible to suppress local uneven distribution of the exhaust gas, that is, to improve the durability of the exhaust gas purification device. Incidentally, as the metal case, not only the one having a structure in which the plurality of honeycomb core bodies fixed in the metal case are in contact with the outer peripheral surfaces in the vicinity of both ends thereof and the other portion has the expanded diameter portion, When using the one having the expanded diameter portion spanning the central portion except the vicinity of both ends of the case, it is possible to guide the high temperature exhaust gas of the separated portion to the void portion of the outer peripheral surface of the honeycomb core body, The temperature distribution in the honeycomb core body can be made uniform.

Embodiments of the present invention will be described below with reference to the drawings, but it goes without saying that the present invention is not limited to the illustrated ones.

1 and 2 show an embodiment of an exhaust gas purifying apparatus according to the present invention. FIG. 1 is a partially cutaway perspective view of the exhaust gas purifying apparatus, and FIG. FIG.

As shown in the drawing, an exhaust gas purifying device according to the present invention (1)
The two honeycomb core bodies (2, 2) are open at both ends, and inside the metal case (3) having the expanded diameter portions (31, 32) excluding both end portions and the central portion, The honeycomb core bodies (2, 2) are arranged with a predetermined width apart from each other, and are manufactured by fixing the respective honeycomb core bodies (2, 2) and the metal case (3).

In the fixing, the respective honeycomb core bodies (2, 2) and the metal case (3) are fixed to each other by opening the metal case (3) of the respective honeycomb core bodies (2, 2) as shown in FIG. The outer peripheral surface in the vicinity of the portion is fixed by brazing, while the outer peripheral surface in the vicinity of the separated portion is brought into contact with the inner wall surface of the central portion of the metal case.

The honeycomb core body (2) has a flat strip material (21) made of a heat-resistant thin steel plate and a corrugated strip material (22) obtained by corrugating the flat strip material (21) in contact with each other. It is manufactured by stacking so as to have a part and then winding and laminating both in a spiral shape. By this winding and stacking, a large number of mesh-like ventilation hole passages (23) which become exhaust gas passages are automatically formed.

As the flat strip (21), for example, a heat-resistant steel of Cr20%, Al5% having a thickness of 0.05 mm and a width of 30 mm, and a corrugated strip (22)
As the flat plate-shaped strip material (21), a corrugated material is used. In this example, two honeycomb core bodies having a short axial length, which were manufactured by winding and laminating these members, were used to form a honeycomb core body (2, 2).

FIG. 3 is a partial longitudinal sectional view of an exhaust gas purifying apparatus according to a second embodiment of the present invention. Compared with the first embodiment, only the shape of the expanded diameter portion (31 ', 32') of the metal case is different.

4 to 5 show an exhaust gas purifying apparatus according to a third embodiment of the present invention. FIG. 4 is a perspective view and FIG. 5 is a sectional view taken along the line AA of FIG. is there. In this third embodiment, as a tubular metal case, both ends are open, and a diameter-expanded portion is provided at a portion excluding both ends and the central portion, and further, a diameter-expanded portion is provided over the central portion. Stuff used. In the exhaust gas purifying apparatus of the third embodiment, the high temperature exhaust gas of the separated portion is formed in the expanded diameter portion (31, 32) of the metal case as compared with the first to second embodiments. Since it is guided to the voids, a greater heat insulating and heat retaining effect can be exerted, and the temperature inside the honeycomb core body in the metal case can be made more uniform.

FIG. 6 is a front view of an exhaust gas purifying apparatus according to a fourth embodiment of the present invention. Compared to the first embodiment, this is a honeycomb core body manufactured by stacking flat plate-shaped strips and corrugated strip-shaped strips in a layered manner, and a metal case having a racetrack-shaped cross section. The difference is that is used.

[Effect of device]

In the exhaust gas purifying apparatus of the present invention, a plurality of honeycomb core bodies are arranged in a metal case having a predetermined width separated from each other, both ends being open, and a large-diameter portion at a key portion, and It is manufactured by fixing one end and the other end of the contact surface between the outer peripheral surface in the vicinity of both ends of the honeycomb core body and the inner wall surface of the non-expanded portion of the metal case. In the metal case, a space between the honeycomb core bodies and a space between the outer peripheral surface of the honeycomb core body and the expanded diameter portion of the metal case are formed. If the metal case has an enlarged diameter portion at a key portion and further has an enlarged diameter portion extending over the central portion of the metal case, the spacing portion and the void portion can be communicated with each other.

The exhaust gas purifying apparatus of the present invention has the following excellent effects by utilizing the fixing means and forming the space.

(i) Deformation (strain) due to the thermal stress in the axial direction of the honeycomb core body so that the separating portion provided between the plurality of honeycomb core bodies can expand and contract in the axial direction of the honeycomb core body in the vicinity of the separating portions. Can be effectively absorbed. Therefore, not only peeling between the honeycomb core body and the metal case,
In particular, it effectively prevents the peeling between the flat plate-shaped strip and the corrugated strip-shaped strip that form the honeycomb core near the outer peripheral surface of the honeycomb core that is subjected to thermal stress strain, and the cracking and damage of these members. be able to.

(ii) By providing the separated portion between the honeycomb core bodies, it is possible to impart an effect of causing turbulence in the flow of exhaust gas, so that the exhaust gas purification performance is made uniform and the temperature distribution inside the honeycomb core body is Can be made uniform.

(iii) Since the voids provided between the outer peripheral portion of the honeycomb core body and the expanded diameter portion of the metal case perform adiabatic heat retention, the temperature distribution inside the honeycomb core body is made more uniform. Further, when a cylindrical metal case having both ends opened, an enlarged diameter portion at a key portion, and an enlarged diameter portion extending over the central portion is used, the void portion communicates with the spacing portion. As a result, the high temperature exhaust gas in the separated portion is guided to the void portion, so that a greater adiabatic heat retention effect is exhibited and the temperature distribution is further improved. This is an important point in improving the deterioration of durability due to uneven distribution of thermal stress strain of the exhaust gas purification device.

(iv) Since the non-fixed end portion of the honeycomb core body is brought into contact with the inner wall surface of the metal case, the exhaust gas purifying apparatus can be provided in which the vibration resistance does not deteriorate against the vibration during traveling of the automobile.

[Brief description of drawings]

FIG. 1 is a partially cutaway perspective view of an exhaust gas purifying apparatus according to a first embodiment of the present invention, and FIG. 2 is a partial longitudinal sectional view of an exhaust gas purifying apparatus according to the first embodiment. FIG. 3 is a partial vertical cross-sectional view of the exhaust gas purification device of the second embodiment. FIG. 4 is a perspective view of the exhaust gas purifying apparatus of the third embodiment, and FIG.
It is the sectional view on the AA line of a figure. FIG. 6 is a front view of the exhaust gas purification apparatus of the fourth embodiment. DESCRIPTION OF SYMBOLS 1 ... Exhaust gas purifying device 2 ... Honeycomb core body 21 ... Flat strip material 22 ... Corrugated strip material 23 ... Mesh ventilation hole 3 ... Metal case 31, 32 ... Expanded part of metal case

Claims (5)

[Scope of utility model registration request] 1. A plurality of honeycomb core bodies having a large number of mesh-like air vent passages in the axial direction, which are manufactured by stacking flat plate-shaped strips and corrugated strips of thin metal plates so as to abut each other. Exhaust gas that is fixedly spaced apart in a metal case that is open at both ends and that is in contact with the outer peripheral surface in the vicinity of both ends of each honeycomb core body, and that is expanded in other parts In the exhaust gas purifying device for carrying the purifying catalyst, the honeycomb core body and the metal case are fixed to each other at the contact surface between the outer peripheral surface in the vicinity of both ends of each honeycomb core body and the inner wall surface of the metal case. An exhaust gas purifying device, characterized in that one end is fixed and the other end is abutted. 2. The honeycomb core body is manufactured by stacking flat strips and corrugated strips so that they come into contact with each other, and winding and laminating them in a spiral shape. Exhaust gas purifier according to. 3. The exhaust gas purifying apparatus according to claim 1, wherein the honeycomb core body is manufactured by laminating flat plate-shaped strips and corrugated plate-shaped strips in a layered structure. 4. The exhaust gas purifying apparatus according to claim 1, wherein the metal case has a circular cross section. 5. The exhaust gas purifying apparatus according to claim 1, wherein the metal case has a racetrack cross section.