JP2004100598A - Exhaust emission control device of engine and joint pipe for controlling emissions having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust emission control device of an engine that can be easily welded to an exhaust pipe and can stably maintain the junction state for a long time, and to provide a joint pipe for controlling emissions that has the exhaust emission control device, can improve manufacturing efficiency and stability in a junction state, can be installed at the exhaust pipe closer to the engine, and can improve emission control performance. <P>SOLUTION: The exhaust emission control device 1 has a cylindrical structure 2 for accommodating a metal carrier 3 carrying an exhaust emission control catalyst. The cylindrical structure 2 has a plurality of concentric cylindrical bodies 4, 5 that are made of different kinds of materials being mutually joined by brazing or physical contact. The cylindrical body 5 welded to at least the exhaust pipe is formed by the same quality of material as the welded site of the exhaust pipe. A joint pipe 11 for controlling emissions forms bellows-shaped cylindrical bodies 14 that are welded each other and a cylindrical body 20 at the side of the exhaust emission control device 13. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an exhaust gas purifying apparatus for purifying exhaust gas of an engine, and an exhaust gas purifying joint pipe having the exhaust gas purifying apparatus.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, in vehicles equipped with an engine, an exhaust gas purifying device is provided in the exhaust pipe to purify exhaust gas, thereby reducing NOx, HC, CO, and the like.
[0003]
Examples of this type of exhaust gas purifying apparatus include those shown in perspective views and cross sectional views in FIGS. 4 and 5, respectively. This exhaust gas purifying device 51 is formed by laminating or winding a flat metal foil (flat foil) made of, for example, stainless steel foil and a corrugated metal foil (corrugated foil) to form an exhaust gas purifying catalyst. (See, for example, Patent Document 1).
[0004]
Further, there is an exhaust gas purifying device as shown in a vertical sectional view in FIG. This exhaust gas purifying device 55 is different from the exhaust gas purifying device 51 shown in FIGS. 4 and 5 in that a tubular body 56 is provided between a metal carrier 52 and a tubular body 53 to form a double pipe structure. 52 is brazed at a brazing portion 57 on the inner peripheral side at one end of the inner cylindrical body 56, and the inner cylindrical body 56 is brazed to the outer cylindrical body 53 at a brazing portion 58 on the outer periphery at the other end. Things. The space between the metal carrier 52 except the brazing portion 57 and the inner tubular body 56 and the space between the inner tubular body 56 except the brazing portion 58 and the outer tubular body 53 are respectively provided. Is formed (for example, Patent Document 2).
[0005]
According to this exhaust gas purifying device 55, the metal carrier 52 is brazed at the brazing portion 57 at one end of the inner tubular body 56, and the inner tubular body 56 is brazed at the brazing portion 58 at the other end. Since the metal carrier 52 is heated to a high temperature and thermally expanded, the brazed portion 57 at one end of the inner cylindrical body 56 is thermally expanded because the metal carrier 52 is brazed to the cylindrical body 53. However, since the brazed portion 58 at the other end is not in contact with the metal carrier 52, it does not expand, and the thermal expansion of the metal carrier 52 is not transmitted to the outer cylindrical body 53. The metal carrier 52 can expand without being restrained by the outer tubular body 53.
[0006]
Therefore, generation of thermal stress is suppressed, the heat-resistant fatigue characteristics of the metal carrier 52 can be improved, and the life of the metal carrier 52 can be extended. In addition, because of the double tube structure, the heat insulation properties of the metal carrier 52 can be improved, and the sound radiated from the metal carrier 52 to the outside can be reduced.
[0007]
The above-described exhaust gas purifying device is usually provided at a plurality of locations in the exhaust pipe. In recent years, however, the exhaust gas purifying catalyst carried on the metal carrier is activated immediately after the engine because of activation at high temperatures. It may be installed in the exhaust pipe.
[0008]
In this case, since the place where the exhaust gas purifying device is installed becomes hot immediately after the engine, and the tubular body thermally expands, the main purpose is to absorb the thermal expansion thereof, and generally, at the inlet side of the exhaust gas purifying device. 2. Description of the Related Art An exhaust gas purification joint pipe provided with a bellows-shaped tubular body welded to a tubular body is used.
[0009]
[Patent Document 1]
Japanese Utility Model Application No. 1-52419 (Microfilm of Japanese Utility Model Application Laid-Open No. 2-142625, page 8 to page 13, FIGS. 1 and 2)
[Patent Document 2]
JP 2001-179111 A (paragraph number 0022, FIG. 7)
[0010]
[Problems to be solved by the invention]
By the way, in the above-mentioned conventional exhaust gas purifying devices 51 and 55, the tubular bodies 53 and 56 for accommodating the metal carrier 52 are formed of a material having excellent strength (generally, ferritic stainless steel). For this reason, when the cylindrical body 53 is installed by welding to the exhaust pipe, the material differs depending on the constituent material of the exhaust pipe, making the welding operation difficult, and welding due to a difference in expansion coefficient between the materials due to a temperature change. There is a concern that a crack or the like may occur in the portion, and the bonded state cannot be stably maintained for a long period of time.
[0011]
The exhaust gas purifying apparatus 55 having the double pipe structure shown in FIG. 6 is manufactured by inserting the tubular body 56 into the tubular body 53 after accommodating the metal carrier 52 in the tubular body 56. However, since the outer tubular body 53 has a margin for welding to the exhaust pipe, the length thereof is generally longer than that of the inner tubular body 56. For this reason, it becomes difficult to position the tubular body 56 at a predetermined position in the tubular body 53, and the production efficiency is reduced.
[0012]
Further, in an exhaust gas purifying joint pipe having such an exhaust gas purifying device, the bellows-like cylindrical body provided on the inlet side is formed of a material excellent in workability (generally, austenitic stainless steel), The material is different from that of the tubular member on the exhaust gas purification device side to be welded. For this reason, there is a concern that the welding operation becomes difficult, the production efficiency is reduced, and the stability of the joined state is impaired. Furthermore, since there are welded parts of different materials, the exhaust temperature is limited by the allowable temperature of the welded parts, and thus the installation location of the exhaust gas purifying joint pipe is limited, and the exhaust gas purifying catalyst is activated at a higher temperature. There is also a concern that it may become an obstacle in improving the purification performance.
[0013]
As a method of joining the tubular body of the exhaust gas purifying apparatus to an exhaust pipe or a bellows-like tubular body of a different material, in addition to the above-described welding method, a flange is provided at each joint end to provide a bolt or the like. However, in this case, the provision of a flange or the use of a bolt or the like may increase the cost and increase the weight.
[0014]
Accordingly, a first object of the present invention, which has been made in view of the above points, is mainly to provide an exhaust gas of an engine which can be easily welded to an exhaust pipe and which is appropriately structured so that the joined state can be stably maintained for a long period of time. It is to provide a gas purification device.
[0015]
Further, a second object of the present invention is to provide a joint pipe for purifying exhaust gas, which can mainly improve the production efficiency and stability of the joined state, can be installed in an exhaust pipe closer to the engine, and can improve the purification performance. It is in.
[0016]
[Means for Solving the Problems]
An invention of an exhaust gas purifying apparatus according to claim 1 which achieves the first object, in an exhaust gas purifying apparatus joined to an exhaust pipe of an engine by welding, accommodates a metal carrier carrying an exhaust gas purifying catalyst. Having a cylindrical structure, the cylindrical structure has a plurality of concentric cylindrical bodies made of different materials, and the plurality of cylindrical bodies are joined to each other by brazing; The tubular body to be welded to the exhaust pipe is made of the same material as the welding part of the exhaust pipe.
[0017]
According to the first aspect of the present invention, the plurality of cylindrical bodies can be formed of a different appropriate material, at least a cylindrical body welded to the exhaust pipe is made of the same material as the welded portion of the exhaust pipe. It is possible to stably maintain the joined state over a long period of time, and it is possible to maintain the heat insulating property and the sound insulation of the radiated sound of the metal carrier. In addition, the plurality of cylindrical bodies are joined to each other by brazing, and since there is no welded portion of a different material inside, the exhaust gas purifying catalyst is activated at a high temperature without being limited by the exhaust gas temperature, and the purifying performance is improved. It can be improved.
[0018]
The invention of an exhaust gas purifying device according to claim 2 is an exhaust gas purifying device joined to an exhaust pipe of an engine by welding, comprising a tubular structure accommodating a metal carrier carrying an exhaust gas purifying catalyst, The tubular structure has a plurality of concentric tubular bodies made of different materials, and the plurality of tubular bodies are joined to each other by physical contact and at least welded to the exhaust pipe. The body is made of the same material as the welding portion of the exhaust pipe.
[0019]
According to the second aspect of the invention, in addition to the same operation and effect as the first aspect of the invention, since the plurality of cylindrical bodies are mutually joined by physical contact, it is possible to easily join them by press-fitting or the like. .
[0020]
According to a third aspect of the present invention, in the exhaust gas purifying apparatus according to the first or second aspect, the outer peripheral cylindrical body other than the innermost peripheral cylindrical body of the cylindrical structure accommodating the metal carrier includes: A peephole for observing the position of the tubular body on the inner peripheral side is formed, and the peephole is closed after the observation.
[0021]
According to the third aspect of the present invention, in manufacturing the exhaust gas purifying apparatus, when the cylindrical body containing the metal carrier is inserted into the outer cylindrical body, a peephole formed in the outer cylindrical body is used. Since the insertion position of the inner tubular body can be observed, the inner tubular body can be easily positioned at a predetermined position of the outer tubular body, and the production efficiency can be improved.
[0022]
Further, the invention of the joint pipe for purifying exhaust gas according to claim 4, which achieves the second object, is a joint pipe for purifying exhaust gas which is coupled to an exhaust pipe of an engine, wherein the bellows-shaped cylinder is provided. A bellows-shaped structure having a cylindrical body, and an exhaust gas purifying device containing a metal carrier carrying an exhaust gas purifying catalyst in a cylindrical structure having a cylindrical body welded to the bellows-shaped cylindrical body, The bellows-shaped tubular body and the tubular body on the exhaust gas purifying apparatus side to be welded thereto are formed of the same material.
[0023]
According to the fourth aspect of the present invention, since the tubular body on the exhaust gas purifying device side welded to the bellows-like tubular body is formed of the same material as the bellows-like tubular body, it can be easily welded, and the production efficiency can be improved. And the bonding state can be stably maintained over a long period of time. Further, since there is no welded portion of a different material, the exhaust temperature is not limited, so that it is possible to further improve the purification performance by installing the exhaust pipe closer to the engine.
[0024]
According to a fifth aspect of the present invention, in the exhaust gas purifying joint pipe of the fourth aspect, the exhaust gas purifying apparatus has a plurality of concentric cylindrical bodies made of different materials as the cylindrical structure, At least one of the plurality of cylindrical bodies welded to the bellows-like cylindrical body is formed of the same material as the bellows-like cylindrical body.
[0025]
According to the fifth aspect of the present invention, since the metal carrier is surrounded by the plurality of cylindrical bodies, it is possible to improve the heat insulating property and the sound insulation of the radiated sound of the metal carrier.
[0026]
According to a sixth aspect of the present invention, in the exhaust gas purifying joint pipe of the fifth aspect, the bellows-like tubular body is made of austenitic stainless steel, and the tubular structure is an inner tubular body made of ferritic stainless steel. And an outer tubular body made of austenitic stainless steel, and the outer tubular body and the bellows-like tubular body are welded to each other.
[0027]
According to the invention of claim 6, the bellows-like cylindrical body can be easily processed, and on the exhaust gas purification device side, since the inner cylindrical body is made of ferritic stainless steel, sufficient strength can be secured. It becomes.
[0028]
According to a seventh aspect of the present invention, in the exhaust gas purifying joint pipe according to the sixth aspect, a peephole for observing a position of the inner cylindrical body is formed in the outer cylindrical body, and after the observation, the peephole is formed. The hole is closed.
[0029]
According to the seventh aspect of the invention, the same operation and effect as the third aspect of the invention can be obtained in manufacturing the exhaust gas purifying apparatus.
[0030]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to FIGS.
[0031]
(1st Embodiment)
1 and 2 show a first embodiment of the present invention. FIG. 1 is a front view of an exhaust gas purifying apparatus, and FIG. 2 is a longitudinal sectional view thereof. The exhaust gas purifying apparatus 1 has a cylindrical structure 2 in which a metal carrier 3 carrying an exhaust gas purifying catalyst is accommodated. The cylindrical structure 2 has a concentric inner cylindrical body 4 and an outer cylindrical body 4. A metal pipe 3 is accommodated in an inner tubular body 4 of the double tubular structure, and the outer tubular body 5 is welded to an exhaust pipe of an engine (not shown).
[0032]
The metal carrier 3 is formed into a honeycomb shape by laminating or winding a flat metal foil (flat foil) made of, for example, stainless steel foil and a corrugated metal foil (corrugated foil). It is brazed and fixed at the brazing portion 6 on the inner circumference. Note that a space is formed between the metal carrier 3 excluding the brazing portion 6 and the inner cylindrical body 4.
[0033]
The outer tubular body 5 is formed of the same material as the material of the welded portion of the exhaust pipe to which the outer tubular body 5 is welded and joined, and the inner tubular body 4 is formed of a different material from the outer tubular body 5. For example, when the welded portion of the exhaust pipe is made of iron, the outer tubular body 5 is formed of iron, and the inner tubular body 4 is formed of another material such as aluminum or ferritic stainless steel. When the portion is made of austenitic stainless steel, the outer tubular body 5 is formed of austenitic stainless steel, and the inner tubular body 4 is formed of another material such as ferritic stainless steel. The inner cylindrical body 4 and the outer cylindrical body 5 are fixed by brazing at a brazing portion 7 on the outer periphery of the end opposite to the brazing portion 6 at one end of the inner cylindrical body 4. Note that a space is also formed between the inner cylindrical body 4 and the outer cylindrical body 5 excluding the brazing portion 7.
[0034]
In addition, the outer cylindrical body 5 is formed with a peephole 8 (shown by a broken line in FIG. 1) for visually observing and determining the insertion position of the inner cylindrical body 4 housed therein, and after positioning, This viewing hole 8 is preferably closed with the same material as the outer cylindrical body 5.
[0035]
According to the exhaust gas purifying apparatus 1 of the present embodiment, since the outer tubular body 5 to be welded to the exhaust pipe is formed of the same material as the welded portion of the exhaust pipe, the outer tubular body 5 can be easily welded to the exhaust pipe. The joined state can be stably maintained over a long period of time, and the heat insulating property and the sound insulation of the radiated sound of the metal carrier 3, which are the features of the double pipe structure, can be stably maintained.
[0036]
Further, the metal carrier 3 is brazed at a brazing portion 6 at one end of the inner cylindrical body 4, and the inner cylindrical body 4 is brazed to the outer cylindrical body 5 at a brazing portion 7 at the other end. Therefore, when the metal carrier 3 is heated to a high temperature and thermally expanded, even if the brazing portion 6 at one end of the inner cylindrical body 4 expands in accordance with the thermal expansion of the metal carrier 3, The brazing portion 7 at the other end of the body 4 does not expand because it is not in contact with the metal carrier 3, the thermal expansion of the metal carrier 3 is not transmitted to the outer tubular body 5, and the metal carrier 3 It can expand without being restricted by the tubular body 5. Therefore, the generation of thermal stress is suppressed, the thermal fatigue resistance of the metal carrier 3 can be improved, and the life of the metal carrier 3 can be extended.
[0037]
Further, the inner tubular body 4 and the outer tubular body 5 are joined to each other by brazing, and since there is no welded portion of a different material inside, there is no restriction on the exhaust temperature. Therefore, the exhaust gas purification catalyst can be activated at a high temperature, and the purification performance can be improved.
[0038]
Further, a peephole 8 for observing the position of the inner cylindrical body 4 is formed in the outer cylindrical body 5 and, after positioning, the peephole 8 is closed. When the inner cylindrical body 4 containing the metal carrier 3 is inserted into the outer cylindrical body 5 during manufacturing, the insertion position of the inner cylindrical body 4 can be visually confirmed through the viewing hole 8. It can be easily positioned at a predetermined position of the outer cylindrical body 5, and the manufacturing efficiency can be improved.
[0039]
(2nd Embodiment)
FIG. 3 is a partial cross-sectional view illustrating a configuration of an exhaust gas purifying joint pipe according to a second embodiment of the present invention. The exhaust gas purifying joint pipe 11 has a bellows-like structure 12 and an exhaust gas purifying device 13 welded thereto.
[0040]
The bellows-like structure 12 has a bellows-like tubular body 14 and an inner tubular body 15 provided inside the bellows-like tubular body 14, and the bellows-like tubular body 14 and the inner tubular body 15 are on the inlet side thereof. At one end, it is fixed to the flange 16 by brazing. In the present embodiment, the bellows-like cylindrical body 14 is formed of austenitic stainless steel having excellent workability, and the inner cylindrical body 15 is formed of, for example, ferritic stainless steel having excellent heat resistance.
[0041]
Further, the exhaust gas purifying device 13 is configured by housing a metal carrier 18 supporting an exhaust gas purifying catalyst in a tubular structure 17. In the present embodiment, the tubular structure 17 is And a double tube structure having an outer cylindrical body 20. Here, the inner cylindrical body 19 is formed of, for example, a ferritic stainless steel having excellent heat resistance, and the metal carrier 18 is fixed therein by brazing in the same manner as in the first embodiment.
[0042]
Further, the outer tubular body 20 is formed of the same austenitic stainless steel as the bellows-like tubular body 14, and the inner tubular body 19 accommodating the metal carrier 18 therein is formed in the same manner as in the first embodiment. It is fixed by brazing, and one end serving as the inlet side of the outer tubular body 20 is welded to the other end serving as the outlet side of the bellows-shaped tubular body 14, and the other end serving as the outlet side of the outer tubular body 20 is provided. The part is provided with a flange 21 by brazing. Note that, similarly to the first embodiment, a peephole 22 (shown by a broken line in FIG. 3) for visually confirming the insertion position of the inner cylindrical body 19 housed therein is provided in the outer cylindrical body 20. After being formed and positioned, this viewing hole 22 is preferably closed with the same material as the outer tubular body 20.
[0043]
This exhaust gas purification joint pipe 11 is used by connecting the flange 16 to the upstream exhaust pipe near the engine and connecting the flange 21 to the downstream exhaust pipe near the engine.
[0044]
According to the exhaust gas purifying joint pipe 11 of the present embodiment, the outer tubular body 20 on the side of the exhaust gas purifying device 13 welded to the bellows-like tubular body 14 is made of the same austenitic stainless steel as the bellows-like tubular body 14. Therefore, welding can be easily performed, manufacturing efficiency can be improved, and the joined state can be stably maintained for a long period of time. In addition, since there is no welded portion of a different material, the exhaust temperature is not limited, and the exhaust temperature can be further improved by installing the exhaust pipe closer to the engine. Further, since the exhaust gas purifying device 13 is formed in the same manner as in the first embodiment, the same effect can be obtained.
[0045]
The present invention is not limited to the above-described embodiment, but can be variously modified without departing from the spirit of the invention. For example, in the first and second embodiments, each of the tubular structures constituting the exhaust gas purifying device is not limited to the double pipe structure, and may have a multi-layer structure of three or more pipes. In the embodiment, the tubular structure of the exhaust gas purifying apparatus may be formed of one tubular body made of the same material as the bellows tubular body. Further, when the tubular structure of the exhaust gas purifying device has a structure of a double pipe or more, the fixing method of the tubular members is not limited to brazing, and may be fixed by physical contact such as press fitting. it can. This eliminates the need for a brazing operation, and allows for easier and more efficient manufacture. Furthermore, the viewing hole of the exhaust gas purifying device can be omitted.
[0046]
【The invention's effect】
As described above, according to the exhaust gas purifying apparatus of the present invention, the tubular structure accommodating the metal carrier includes a plurality of concentric tubular bodies made of different materials, and at least the engine Since the tubular body to be welded to the exhaust pipe is made of the same material as the welded portion of the exhaust pipe, it can be easily welded to the exhaust pipe, and the joined state can be stably maintained for a long period of time. Therefore, it is possible to stably maintain characteristics such as a heat insulating property of the metal carrier and a sound insulation property of radiated sound by the multi-tube structure.
[0047]
Further, according to the joint pipe for purifying exhaust gas of the present invention, since the tubular body on the exhaust gas purifying device side welded to the bellows-like tubular body is formed of the same material as the bellows-like tubular body, it is easy to use. Welding can improve the production efficiency, and can stably maintain the joining state over a long period of time.Also, since there is no welding portion of a different material, the exhaust temperature is not limited, and It can be installed in an exhaust pipe close to the engine to further improve purification performance.
[Brief description of the drawings]
FIG. 1 is a front view of an exhaust gas purification device according to a first embodiment of the present invention.
FIG. 2 is a longitudinal sectional view of FIG.
FIG. 3 is a partial cross-sectional view illustrating a configuration of an exhaust gas purifying joint pipe according to a second embodiment of the present invention.
FIG. 4 is a perspective view illustrating a configuration of an example of a conventional exhaust gas purification device.
FIG. 5 is a cross-sectional view of FIG.
FIG. 6 is a longitudinal sectional view showing the configuration of another example of a conventional exhaust gas purification device.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Exhaust gas purifier 2 Cylindrical structure 3 Metal carrier 4 Inner cylindrical body 5 Outer cylindrical body 6, 7 Brazing part 8 Peephole 11 Exhaust gas purifying joint pipe 12 Bellows-like structure 13 Exhaust gas purifier 14 Bellows-like cylindrical body 15 Inner cylindrical body 17 Cylindrical structure 18 Metal carrier 19 Inner cylindrical body 20 Outer cylindrical body 22 Peephole

Claims (7)

In an exhaust gas purification device that is joined to the exhaust pipe of an engine by welding,
A cylindrical structure accommodating a metal carrier supporting an exhaust gas purifying catalyst, the cylindrical structure having a plurality of concentric cylindrical bodies made of different materials; An exhaust gas purifying apparatus for an engine, wherein the tubular body is joined to each other by attachment and at least a tubular body welded to the exhaust pipe is made of the same material as a welded portion of the exhaust pipe. In an exhaust gas purification device that is joined to the exhaust pipe of an engine by welding,
A cylindrical structure accommodating a metal carrier supporting an exhaust gas purification catalyst, the cylindrical structure having a plurality of concentric cylindrical bodies made of different materials, and the plurality of cylindrical bodies being physical; An exhaust gas purifying apparatus for an engine, wherein the cylindrical body is joined to each other by a mechanical contact and at least a tubular body welded to the exhaust pipe is made of the same material as a welded portion of the exhaust pipe. Forming a peephole for observing the position of the inner cylindrical body in the outer cylindrical body excluding the innermost cylindrical body of the cylindrical structure that houses the metal carrier, and observing 3. The exhaust gas purifying apparatus for an engine according to claim 1, wherein the sight hole is closed thereafter. In an exhaust gas purification joint pipe that purifies exhaust gas by coupling to the exhaust pipe of the engine,
A bellows-like structure having a bellows-like cylindrical body,
An exhaust gas purification device containing a metal carrier carrying an exhaust gas purification catalyst in a tubular structure having a tubular body welded to the bellows-like tubular body,
An exhaust gas purifying joint pipe, wherein the bellows-like tubular body and the tubular body on the exhaust gas purifying device side to be welded thereto are formed of the same material. The exhaust gas purifying apparatus has a plurality of concentric cylindrical bodies made of different materials as the cylindrical structure, and at least one of the plurality of cylindrical bodies welded to the bellows cylindrical body. The joint pipe for purifying exhaust gas according to claim 4, wherein the body is formed of the same material as the bellows-like cylindrical body. The bellows-shaped tubular body is made of austenitic stainless steel, and the tubular structure has two tubular bodies, an inner tubular body made of ferritic stainless steel and an outer tubular body made of austenitic stainless steel, 6. The exhaust gas purifying joint pipe according to claim 5, wherein the outer tubular body and the bellows-like tubular body are welded. 7. The exhaust gas purification apparatus according to claim 6, wherein a peephole for observing the position of the inner cylindrical body is formed in the outer cylindrical body, and the peephole is closed after the observation. For joint pipe.

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