JP2021156225A - Manufacturing method of exhaust emission control system, and exhaust emission control system - Google Patents

Abstract

To propose a technique for suppressing influence of thermal stress.SOLUTION: A manufacturing method of an exhaust emission control system is provided. The exhaust emission control system includes a metallic cylindrical bent pipe portion as a flow channel of an exhaust gas. This method includes a load application process to keep a state that a load pulled toward an upstream side and a downstream side of the flow channel is applied to at least a bent part of the bent pipe portion.SELECTED DRAWING: Figure 5

Description

The present disclosure relates to an exhaust gas purification system provided in an internal combustion engine.

The internal combustion engine may vibrate during operation. Therefore, it is desired that the exhaust gas purification system arranged in the vicinity of the internal combustion engine has improved resistance to vibration. Patent Document 1 below discloses an exhaust gas purification device that holds a three-way catalyst and a gasoline particulate filter (hereinafter, GPF) in a case including a tubular member bent in an L shape. In this case, the three-way catalyst and the GPF are arranged adjacent to each other at different angles of 90 degrees. As a result, the case becomes compact, so that it can be arranged close to the engine or the transmission, and the length of the stay for fixing the case can be shortened. The shorter the stay, the easier it is to improve the support rigidity of the case.

Japanese Patent No. 6418263

The exhaust gas discharged from the internal combustion engine has a higher temperature as it is closer to the internal combustion engine, and the piping closer to the internal combustion engine tends to have a higher temperature due to the heat of the exhaust gas and tends to expand thermally. When the support rigidity of the case is high as in Patent Document 1 described above, the stress corresponding to the thermal strain tends to be large. In particular, in the case of an L-shape, stress is concentrated on the bent portion, which can be one of the factors such as deformation and breakage of the case.

An object of the present disclosure is to propose a technique for suppressing the influence of thermal stress.

One aspect of the present disclosure is a method of manufacturing an exhaust gas purification system. This exhaust gas purification system includes a bent metal tubular bent pipe portion that serves as an exhaust gas flow path. This method includes a loading step that maintains a state in which a load that is pulled toward the upstream side and the downstream side of the exhaust gas flow path is maintained at least at the bent portion in the bent pipe portion.

The exhaust gas purification system manufactured by such a manufacturing method is in a state in which a load is applied so as to be pulled toward the upstream side and the downstream side with respect to the bent portion of the bent pipe portion by the applied load process. When the bent pipe portion is heated by the operation of an internal combustion engine or the like, the bent portion thermally expands. Here, the thermal stress generated by the thermal elongation in the direction opposite to the upstream side and the downstream side of the exhaust gas flow path when viewed from the bent portion is in the opposite direction to the above-mentioned load applied to the bent portion in advance. Since it is a force, the thermal stress is canceled by the above-mentioned load and becomes smaller. That is, the bent portion of the bent pipe portion can be in a state in which the thermal stress due to thermal strain is suppressed. When the internal combustion engine is in operation, heat and vibration are applied to the bent pipe portion. However, since the bent pipe portion described above can receive its vibration in a state where the thermal stress is suppressed, it is possible to suppress the occurrence of deformation and breakage due to the vibration as compared with the case where it is strongly affected by the thermal stress. ..

In the manufacturing method described above, the bent pipe portion may include an inner peripheral side member and an outer peripheral side member. The inner peripheral side member constitutes the inner peripheral side of the bent portion. The outer peripheral side member constitutes the outer peripheral side of the bent portion. The applied load step includes welding the outer peripheral side member and the inner peripheral side member with a load applied to at least one of the inner peripheral side member and the outer peripheral side member toward the upstream side and the downstream side of the flow path. It may be. The exhaust gas purification system manufactured by such a manufacturing method can be in a state in which the above-mentioned load is applied to the bent pipe portion at the stage of manufacturing the bent pipe portion.

Further, in the manufacturing method described above, in the applied load step, the bent pipe portion is fixed to an external device so that a load is applied to the bent pipe portion toward the upstream side and the downstream side of the flow path. It may be included. In the exhaust gas purification system manufactured by such a manufacturing method, the above-mentioned load is applied to the bent pipe portion at the stage of fixing the bent pipe portion to an external device such as a vehicle engine, transmission, or body. Can be in a state.

The bent pipe portion described above holds at least two purifying devices for purifying the exhaust gas, and at least one purifying device may be arranged on each of the upstream side and the downstream side of the bent portion. The exhaust gas purification system manufactured by such a manufacturing method can hold two purification devices at an angle in the bent pipe portion.

Further, the manufacturing method described above may further include fixing a portion of the bent pipe portion on the upstream side and a portion on the downstream side of the bent portion to an external device. In the exhaust gas purification system manufactured by such a manufacturing method, when the bent pipe portion is heated, heat elongation occurs in the bent portion in the upstream side and the downstream side. Then, the thermal stress due to the generated thermal elongation can be canceled and reduced by the load applied by the applying load process.

Another aspect of the present disclosure is an exhaust gas purification system. The exhaust gas purification system includes a bent metal tubular bent pipe portion that serves as a flow path for exhaust gas. The bent pipe portion is in a state in which a load pulled toward the upstream side and the downstream side of the flow path is applied to at least the bent portion in the bent pipe portion.

With such a configuration, the bent portion of the bent pipe portion is in a state in which a load is applied so as to be pulled toward the upstream side and the downstream side. Therefore, similarly to the exhaust gas purification system manufactured by the above-mentioned manufacturing method, the thermal stress generated based on the operation of the internal combustion engine or the like cancels out the above-mentioned load and becomes small, and the bent portion of the bent pipe portion is thermally strained. The thermal stress due to the above can be suppressed. As a result, it is possible to suppress the occurrence of deformation and breakage due to vibration.

It is a perspective view which shows the exhaust gas purification system of 1st Embodiment. It is a top view which shows the exhaust gas purification system of 1st Embodiment. It is an enlarged view of FIG. It is a figure explaining the manufacturing method of the bent pipe part of 1st Embodiment. It is a figure explaining the manufacturing method of the bent pipe part of 1st Embodiment. It is a figure explaining the manufacturing method of the bent pipe part of 1st Embodiment. It is a figure explaining the stress applied in the applied load process by the bent pipe part of 1st Embodiment. It is a figure explaining the stress generated by thermal expansion in the bent pipe part of 1st Embodiment. It is a figure explaining the stress which a bent pipe part of 1st Embodiment has during engine operation. It is a figure explaining the stress applied to the bent pipe part of 1st Embodiment. It is a figure explaining the manufacturing method of the bent pipe part of 2nd Embodiment.

Hereinafter, embodiments of the present disclosure will be described with reference to the drawings.
[1. First Embodiment]
[1-1. Exhaust gas purification system configuration]
The exhaust gas purification system 10 includes a purification device 1 as shown in FIGS. 1 to 3. Further, the exhaust gas purification system 10 is arranged adjacent to the engine 2 and the transmission 3. The engine 2 and the transmission 3 are arranged in a substantially L shape as a whole in the range shown in the drawing. The purification device 1 is arranged along the engine 2 and the transmission 3 inside the bent portion having a substantially L-shape described above.

The engine 2 is provided with a connection portion 11. By connecting the purification device 1 to the connection portion 11, the purification device 1 is fixed to the engine 2. The transmission 3 is provided with a first fixed base 12 and a second fixed base 13. A first stay 14 is provided on the first fixing base 12. A second stay 15 is provided on the second fixing base 13. The purification device 1 is fixed to the first stay 14 and the second stay 15 using bolts and nuts (not shown), and as a result, the purification device 1 is fixed to the transmission 3.

<Purification device>
The purification device 1 has a bent pipe portion 5 as shown in FIGS. 1 to 4. The bent pipe portion 5 holds at least two purification devices that purify the exhaust gas. As the purification member, for example, as shown in FIG. 4, a three-way catalyst 7a on the upstream side and a GPF 7b on the downstream side may be arranged.

The bent pipe portion 5 is a bent metal tubular member that serves as a flow path for exhaust gas, and has an inflow portion 21, an outflow portion 22, and a connecting portion 23. The bent pipe portion 5 introduces the exhaust gas discharged from the engine 2, purifies it with a purification member, and discharges it to a pipe on the downstream side (not shown).

The inflow portion 21 is a cylindrical member as a whole. An upstream side of the inflow portion 21, that is, an end portion on the engine 2 side, is provided with a connecting port 21a extending in a direction intersecting the axial direction of the inflow portion 21. The connecting port 21a is connected to the connecting portion 11, and the exhaust gas of the engine 2 is introduced into the purification device 1 via the connecting port 21a. Further, on the downstream side of the inflow portion 21, a first insertion portion 21b that is inserted into the connecting portion 23 and is connected to the connecting portion 23 is provided.

The outflow portion 22 is a cylindrical member as a whole. An exhaust port 22a for guiding the exhaust gas to the downstream is provided at the downstream end of the outflow portion 22. Further, on the upstream side of the outflow portion 22, a second insertion portion 22b that is inserted into the connecting portion 23 and is connected to the connecting portion 23 is provided.

The connecting portion 23 has a bent tubular shape that connects the inflow portion 21 and the outflow portion 22. The connecting portion 23 includes an inner peripheral side member 32 that constitutes the inner peripheral side of the bent portion (hereinafter, also referred to as a bent portion), and an outer peripheral side member 31 that constitutes the outer peripheral side of the bent portion. A tubular member is formed by the inner peripheral side member 32 and the outer peripheral side member 31. The first insertion portion 21b is inserted into the opening on the upstream side of the connecting portion 23, and the second insertion portion 22b is inserted into the opening on the downstream side.

[1-2. Manufacturing method of exhaust gas purification system]
First, a method of manufacturing the purification device 1 will be described. As shown in FIG. 4, the welding region 31a located at the upstream end of the outer peripheral member 31 is welded to the inflow portion 21, and the welding region 31b located at the downstream end is welded to the outflow portion 22. do.

Next, as shown in FIG. 5, the inflow portion 21 is held by the first clamp 81, and the outflow portion 22 is held by the second clamp 82. Then, the first clamp 81 is pulled in the axial direction of the inflow portion 21 and away from the outflow portion 22, and the second clamp 82 is pulled in the axial direction of the outflow portion 22 and in the direction away from the inflow portion 21. As a result, a load is applied to the outer peripheral side member 31 toward the upstream side and the downstream side of the exhaust gas flow path. If the above-mentioned load is applied to the outer peripheral side member 31, the pulling directions of the first clamp 81 and the second clamp 82 are not particularly limited. Further, only one of the first clamp 81 and the second clamp 82 may apply a load.

Subsequently, with the load applied as described above, the inner peripheral side member 32 is welded in the welding region 32a as shown in FIG. The welded region 32a is a portion where the inner peripheral side member 32 abuts or overlaps with the outer peripheral side member 31, the inflow portion 21, and the outflow portion 22. Therefore, the outer peripheral side member 31 and the inner peripheral side member 32 are welded by the above operation. The inner peripheral side member 32 is also welded to the inflow portion 21 and the outflow portion 22. Welding of each member may be performed after the purification member is placed at a predetermined position. As described above, the step of welding with the inner peripheral side member 32 in a state where the load is applied to the outer peripheral side member 31 corresponds to the applied load step.

The purification device 1 manufactured as described above is subsequently fixed to the engine 2 and the transmission 3. Specifically, the connecting port 21a is connected to the connecting portion 11 to be fixed to the engine 2, and the bent pipe portion 5 is fixed to the first stay 14 and the second stay 15 to be fixed to the transmission 3. .. That is, a portion of the bent pipe portion 5 on the upstream side and a portion on the downstream side of the bent portion are fixed to an external device of the purification device 1. For example, the first stay 14 and the second stay 15 are fixed to the downstream portion of the exhaust gas in the bent pipe portion 5, but the fixed positions are not limited to this.

The exhaust gas purification system 10 is manufactured through the above-mentioned steps. The bent pipe portion 5 of the purification device 1 is not subjected to a large stress due to attachment to the engine 2 or the transmission 3.

[1-3. Stress applied to purification device]
The bent pipe portion 5 of the exhaust gas purification system 10 manufactured by the above-described manufacturing method is located on the outer peripheral side of the bent portion of the bent pipe portion 5 as shown in FIG. 7 when the engine 2 is not operating and is cold. In particular, a force in the direction indicated by the arrow is applied to the portion (outer peripheral side member 31). That is, a load that is pulled toward the upstream side and the downstream side of the flow path is applied. In other words, the bent pipe portion 5 is in a state in which residual stress in the direction of the arrow is generated. When the engine 2 is operated, the bent pipe portion 5 is heated by the heat of the exhaust gas. Then, the connecting port 21a of the bent pipe portion 5 is fixed to the engine 2, and the first stay 14 and the second stay 15 are also fixed. Therefore, as shown in FIG. 8, a large amount of heat is generated in the flow path direction due to thermal expansion. Elongation occurs and thermal stress in the direction indicated by the arrow occurs. The thermal stress in the direction indicated by the arrow is, that is, the thermal stress in the direction toward the bent portion located at the center of the bent pipe portion 5. As a result, as shown in FIG. 9, in the bent pipe portion 5, the stress remains in the inner peripheral side member 32, but the stress becomes smaller in the outer peripheral side member 31. Note that FIG. 9 shows a state in which the stress applied to the outer peripheral side member 31 is canceled and there is no stress arrow for easy understanding, but it is not necessary to strictly eliminate the stress, and a relatively small stress is present. It may remain in a state.

The stress applied to the bent pipe portion 5 of the present disclosure will be described with reference to the table of FIG. In FIG. 10, the conventional configuration is a purification device having the same configuration as the purification device 1 except that the load-bearing process is not performed. Here, "initial" indicates the stress generated in the cold state in which the engine 2 is not operated. Further, "thermal elongation" indicates a stress generated when only thermal expansion due to engine operation is considered without considering the load applied by the applied load process. Further, "initial + thermal elongation" indicates the sum of stresses of "initial" and "thermal elongation". The compression means a load from the upstream side and the downstream side toward the connecting portion 23, that is, a stress in the direction of compressing the bent pipe portion 5 due to thermal strain due to thermal expansion. Tension means stress in the direction in which the connecting portion 23 is pulled toward the upstream side and the downstream side, contrary to compression. As shown in FIG. 10, in the conventional configuration, only the stress generated by thermal elongation is applied. On the other hand, in the purification device 1 of the embodiment, since the stress directions of the initial heat elongation and the heat elongation are opposite to each other, they are canceled out, and the stress at the time of heat elongation, that is, during the operation of the engine 2 becomes small.

[1-4. effect]
According to the first embodiment described in detail above, the following effects can be obtained.
(1a) In the exhaust gas purification system 10, the purification device 1 is directed toward the upstream side and the downstream side with respect to the outer peripheral side member 31 which is the outer peripheral side portion of the bent portion of the bent pipe portion 5 by the applied load process. The load is maintained so that it is pulled. The thermal stress generated by the heat expansion of the bent pipe portion 5 in the direction opposite to the upstream side and the downstream side due to the heat of the exhaust gas is a force in the direction opposite to the above-mentioned load applied to the bent portion in advance. Therefore, it is canceled by the load given by the applied load process and becomes smaller. That is, the bent portion of the bent pipe portion 5 can be in a state in which the thermal stress due to thermal strain is suppressed. Further, since the engine 2 can be subjected to the vibration in a state where the thermal stress is suppressed during the operation, it is possible to suppress the occurrence of deformation and breakage due to the vibration as compared with the case where the engine 2 is strongly affected by the thermal stress.

(1b) The exhaust gas purification system 10 can be in a state in which a load pulled toward the upstream side and the downstream side is applied to the outer peripheral side member 31 at the stage of manufacturing the bent pipe portion 5. A force opposite to that of the outer peripheral side member 31 is applied to the inner peripheral side member 32. However, since the influence of thermal stress is greater on the outer peripheral side member 31 having a large thermal elongation range, the deformation or breakage of the outer peripheral side member 31 is suppressed, so that the bending pipe portion 5 as a whole is deformed or damaged. Can be suppressed.

For example, by making the plate thickness of the outer peripheral side member 31 larger than the plate thickness of the inner peripheral side member 32, or by adopting a configuration in which ribs or the like are provided on the outer peripheral side member 31, the outer peripheral side member 31 is thermally stretched. If a configuration that is strong against the generated stress is adopted, as a result, the inner peripheral side member 32 may be more vulnerable to the above stress than the outer peripheral side member 31. In this case, by setting the outer peripheral side member 31 with a load that is pulled toward the upstream side and the downstream side, the stress generated by the thermal elongation generated in the inner peripheral side member 32 can be suppressed, and the inner peripheral side member can be suppressed. It is possible to suppress the occurrence of deformation and breakage of 32.

[1-5. Modification example of the first embodiment]
In the first embodiment, a configuration in which welding is performed with the inner peripheral side member 32 in a state where a load is applied to the outer peripheral side member 31 is illustrated. However, the outer peripheral side member 31 and the inner peripheral side member 32 are configured to be welded in a state where a load is applied to the inner peripheral side member 32 toward the upstream side and the downstream side of the exhaust gas flow path. May be good. In that case, it is possible to suppress the influence of the stress generated by the thermal elongation, which is particularly generated on the inner peripheral side member 32.

[2. Second Embodiment]
[2-1. Exhaust gas purification system configuration]
Since the second embodiment has a configuration common to that of the first embodiment, the description of the common configuration will be omitted, and the differences will be mainly described. The same reference numerals as those in the first embodiment indicate the same configurations, and the preceding description will be referred to.

The exhaust gas purification system of the second embodiment includes a purification device 101. The purification device 101 is arranged in the same manner as the purification device 1 of the first embodiment shown in FIG. In the purification device 101 shown in FIG. 11, the connecting portion 123 of the bent pipe portion 105 has the same basic structure as the connecting portion 23. However, the connecting portion 123 is different from the connecting portion 23 of the purification device 1 in that stress is not applied to the outer peripheral side member 31 on the upstream side and the downstream side when the inner peripheral side member 32 and the outer peripheral side member 31 are welded to each other. It's different.

[2-2. Manufacturing method of exhaust gas purification system]
The purification device 101 is manufactured by the same method as that of the first embodiment except that the pressurization by the first clamp 81 and the second clamp 82 as shown in FIG. 5 is not performed.

Fixing the purification device 101 to an external device will be described. The external device referred to here is a device or body constituting a vehicle on which the purification system is mounted, and in the present embodiment, is an engine 2 and a transmission 3 mounted on the vehicle.

First, the connecting port 21a is attached to the connecting portion 11 and fixed. After that, using bolts and nuts, the first stay 14 previously attached to the outflow portion 22 is fixed to the first fixing base 12, and the second stay 15 is fixed to the second fixing base 13. Here, the bolts and nuts are fastened so that the first stay 14 and the second stay 15 are pulled toward the downstream side where the exhaust port 22a is located. This operation is an operation of fixing the bent pipe portion 105 to an external device so that a load is applied to the bent pipe portion 105 toward the upstream side and the downstream side of the flow path. In the present embodiment, the bent pipe portion 105 is slightly deformed at the time of fixing, and the upstream end and the downstream end of the bent pipe 105 are on the upstream side in a state where no load is applied to the bent pipe 105. The distance is wider than the distance between the end of the pipe and the end on the downstream side. However, the bent pipe portion 105 does not have to be deformed as long as a load is applied. As described above, the step of attaching the purification device 1 to the external device in a state where the load is applied to the purification device 1 corresponds to the load application step. The second stay 15 may be fixed to the second fixing base 13, and the first stay 14 may be fixed to the first fixing base 12, and the first stay 14 and the second stay 15 are located at the connecting port 21a. It may be fixed so as to be pulled toward the upstream side.

The exhaust gas purification system of the second embodiment is manufactured through the steps described above. Stress is generated in the purification device 101 due to attachment to the engine 2 and the transmission 3. On the other hand, the purification device 101 does not generate a large residual stress due to its own production.

[2-3. effect]
According to the second embodiment described in detail above, the following effects can be obtained in addition to the effect (1a) of the first embodiment described above.

(2a) In the exhaust gas purification system of the second embodiment, the bent pipe portion 105 is upstream and downstream of the bent pipe portion 5 at the stage of fixing the bent pipe portion 105 to an external device such as an engine 2, a transmission 3, or a body of a vehicle. The load can be applied so as to be pulled toward the side.

[2-4. Modification example of the second embodiment]
In the second embodiment, the configuration in which the connecting portion 123 includes the inner peripheral side member 32 and the outer peripheral side member 31 is illustrated, but the specific mode and manufacturing method of the connecting portion 123 are not particularly limited. For example, the connecting portion 123 is not composed of a plurality of members, but may be configured as one cylindrical member.

Further, in the above embodiment, the configuration in which the purification device 101 is fixed by the connecting portion 11 and the first fixing base 12 and the second fixing base 13 is illustrated, but the purification device 101 may be fixed to other parts. For example, the configuration may be such that the load is maintained by the members such as the first clamp 81 and the second clamp 82 shown in FIG.

[3. Other embodiments]
Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above embodiments, and it goes without saying that various embodiments can be taken as long as they belong to the technical scope of the present disclosure.

(3A) In the above embodiment, as an example of the applied load process, a step of welding with the inner peripheral side member 32 in a state where a load is applied to the outer peripheral side member 31 and fixing with the first stay 14 and the second stay 15 are performed. The step of applying a load to the bent pipe portion 105 at the time was illustrated. However, the load-bearing process is not limited to these processes.

For example, the bent pipe portion may be provided with a new component for maintaining the state in which the bent pipe portion is pulled to the upstream side and the downstream side. For example, a member that connects the inflow portion 21 and the outflow portion 22 while applying a load so as to increase the distance between the inflow portion 21 and the outflow portion 22 is welded to the inflow portion 21, the outflow portion 22, and the connecting portion 23. After that, it may be provided in the bent pipe portion.

Further, in order to bring the bent pipe portion 105 into a state of being pulled to the upstream side and the downstream side as in the second embodiment, the purification device 101 is attached to the vehicle body by using parts other than the first stay 14 and the second stay 15. It may be configured to be fixed. The bent pipe portion 105 may be fixed to the transmission 3 by a stay first, and then a load may be applied to the bent pipe portion 5 when the connecting port 21a is fixed to the connecting portion 11.

(3B) It may be configured to perform both the load-bearing process of the first embodiment and the load-bearing process of the second embodiment. In this case, the magnitude of the load applied to the bent pipe portion can be adjusted, or the load can be made larger than when only one of the steps is executed. Further, for example, it may be combined with another load-bearing process as described in 3A.

(3C) The configuration of the purification member and the bent pipe portion is not limited to the configuration disclosed in the above embodiment. For example, the bent pipe portion may have a shape different from that of the above-described embodiment as long as it has a bent portion. The bent pipe portion may have a shape other than the bent cylindrical shape, for example, a tubular shape having a polygonal cross section. The purification component is not limited to the combination of the three-way catalyst 7a and the GPF7b, and other catalysts and the like may be used. Further, three or more purification members may be held in the bent pipe portion, or one purification member may be held. Further, a member other than the purification member may be arranged. For example, another pipe may be connected to the bent pipe portion, such as a pipe for recirculating EGR gas. A manifold may be arranged at the connecting portion between the engine 2 and the connecting port 21a.

(3D) A plurality of functions possessed by one component in the above embodiment may be realized by a plurality of components, or one function possessed by one component may be realized by a plurality of components. .. Further, a plurality of functions possessed by the plurality of components may be realized by one component, or one function realized by the plurality of components may be realized by one component. Further, a part of the configuration of the above embodiment may be omitted. In addition, at least a part of the configuration of the above embodiment may be added or replaced with the configuration of the other above embodiment.

1,101 ... Purification device, 2 ... Engine, 3 ... Transmission, 5,105 ... Bending pipe part, 7a ... Three-way catalyst, 7b ... GPF, 10 ... Exhaust gas purification system, 11 ... Connection part, 12 ... First fixed Table, 13 ... 2nd fixed base, 14 ... 1st stay, 15 ... 2nd stay, 21 ... Inflow part, 21a ... Connecting port, 21b ... 1st insertion part, 22 ... Outflow part, 22a ... Exhaust port, 22b ... Second insertion portion, 23, 123 ... connecting portion, 31 ... outer peripheral side member, 31a, 31b, 32a ... welding region, 32 ... inner peripheral side member, 81 ... first clamp, 82 ... second clamp.

Claims (6)

It is a manufacturing method of the exhaust gas purification system.
The exhaust gas purification system includes a bent metal tubular bent pipe portion that serves as an exhaust gas flow path.
A method for manufacturing an exhaust gas purification system, which comprises a load-applying step of maintaining a state in which a load pulled toward the upstream side and the downstream side of the flow path is applied to at least the bent portion of the bent pipe portion. The method for manufacturing an exhaust gas purification system according to claim 1.
The bent pipe portion includes an inner peripheral side member constituting the inner peripheral side of the bent portion and an outer peripheral side member forming the outer peripheral side of the bent portion.
In the loading step, the outer peripheral side member and the inner peripheral side member are subjected to a state in which a load is applied to at least one of the inner peripheral side member and the outer peripheral side member toward the upstream side and the downstream side of the flow path. A method of manufacturing an exhaust gas purification system, including welding. The method for manufacturing an exhaust gas purification system according to claim 1.
The load-bearing process
A method for manufacturing an exhaust gas purification system, which comprises fixing the bent pipe portion to an external device so that a load is applied to the bent pipe portion toward the upstream side and the downstream side of the flow path. The method for manufacturing an exhaust gas purification system according to any one of claims 1 to 3.
The bent pipe portion holds at least two purifying devices for purifying exhaust gas, and at least one of the purifying devices is arranged on each of the upstream side and the downstream side of the bent portion to purify the exhaust gas. How the system is manufactured. The method for manufacturing an exhaust gas purification system according to any one of claims 1 to 4.
A method for manufacturing an exhaust gas purification system, which comprises fixing a portion upstream and a portion downstream of the bent portion of the bent pipe portion to an external device. Exhaust gas purification system
The exhaust gas purification system includes a bent metal tubular bent pipe portion that serves as an exhaust gas flow path.
The bent pipe portion is an exhaust gas purification system in which a load pulled toward the upstream side and the downstream side of the flow path is applied to at least the bent portion in the bent pipe portion.

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