JP6507315B2 - Exhaust pipe - Google Patents

Description

  The present disclosure relates to an exhaust pipe that allows exhaust gas to flow down toward a purification device.

  The arrangement section of the purification device in the exhaust pipe may be wider than the section upstream of the arrangement section. Further, in order to reduce the space for arranging the exhaust pipe, the path of the exhaust pipe may be complicated or the width of the exhaust pipe may be reduced. In these cases, exhaust gas may flow into the purification device in a state of being biased to a specific area. As a result, the purification action of the exhaust gas by the purification device may be reduced.

  On the other hand, Patent Document 1 describes that a recessed portion that protrudes toward the inner peripheral side is provided on the outer peripheral side of the curved introduction portion that causes the exhaust gas to flow down the selective reduction catalyst. The recessed portion guides the exhaust gas flowing down on the outer peripheral side of the introduction portion to the inner peripheral side. As a result, the exhaust gas flows into the selective reduction catalyst in a more uniform state.

Patent No. 4920532 gazette

  However, in the technique described in Patent Document 1, the exhaust gas is induced toward the opposite side of the position of the recess. Depending on the shape of the exhaust pipe, it may be difficult to adjust the flow of exhaust gas even if such a recess is used.

  It is desirable to allow the exhaust gas to flow into the purification device so that the purification action of the purification device is fully exhibited.

  An exhaust pipe, which is an aspect of the present disclosure, allows exhaust gas to flow down. The exhaust pipe comprises an upstream part, a connection and at least one projection. The upstream portion is a tubular portion that allows the exhaust gas to flow down. Further, the connection portion is a tubular portion which allows the exhaust gas to flow down, and is connected to the downstream side of the upstream portion. Also, at least one projection projects from the inner wall of the upstream portion and / or the connection portion.

  Moreover, it is a tubular site | part where exhaust gas purification apparatus is arrange | positioned, Comprising: Let an upstream opening be a site | part which has a part wider than an upstream part as a purification part. The connection part is connected to the purification part located downstream of the connection part. Further, in at least one protrusion, a direction from the top to the root side is taken as a guiding direction. At least one projection is curved in a streamlined cross-section along the flow-down direction of the exhaust gas so that the path of the exhaust gas flowing into the region adjacent to the downstream side of the projection is inclined in the induction direction .

  According to such a configuration, the exhaust gas flowing down the vicinity of the at least one protrusion does not separate from the protrusion and flows down along the protrusion. For this reason, the exhaust gas that has flowed into the area adjacent to the downstream side of the projecting portion has its path inclined in the induction direction. As a result, the exhaust gas is inclined at the junction in the guiding direction. Thereby, the flow of the exhaust gas can be suitably adjusted. Therefore, exhaust gas can be made to flow into the purification device so that the purification action of the purification device is sufficiently exhibited.

  In the above configuration, the boundary between the region inside the upstream portion and the region inside the connection portion may be used as the connection port. Further, a region in which at least one protrusion on the inner wall is provided may be a protrusion region. The projecting region may be provided in a state of crossing the connection port, or in a state in which a part of the edge is located along the connection port on the downstream side or upstream side of the connection port.

  According to such a configuration, the path of the exhaust gas is adjusted immediately before or after the timing at which the exhaust gas enters the connecting portion. Therefore, the flow of exhaust gas in the connection portion can be adjusted more suitably. Therefore, exhaust gas can be made to flow into the purification device so that the purification action of the purification device is sufficiently exhibited.

  Further, in the above configuration, the section including the downstream end in the upstream portion may extend in a linear extension direction. Moreover, when the connection port is moved to the downstream side along the extension direction, a region through which the connection port passes may be used as a front area. The top of at least one projection provided in the projecting area located downstream of the connection port and in which a part of the edge is located along the connection port may reach the front area.

  According to such a configuration, it is possible to incline more exhaust gas paths in the induction direction at the connection portion. Therefore, exhaust gas can be made to flow into the purification device so that the purification action of the purification device is sufficiently exhibited.

Furthermore, in the above configuration, the at least one protrusion may be provided in a state of laterally surrounding the flow path of the exhaust gas.
According to such a configuration, the exhaust gas flowing down the edge of the flow path is inclined outward after entering the connection. That is, it is possible to diffuse the path of the exhaust gas to the outside at the connection portion. This makes it possible to flow the exhaust gas into the purification device in a more uniform state. As a result, it is possible to fully exhibit the purification action of the purification device.

FIG. 1A is a front view of the exhaust pipe of the first embodiment. 1B and 1C are side views of the exhaust pipe of the first embodiment. FIG. 1D is a 1D-1D cross-sectional view of the exhaust pipe of the first embodiment. FIG. 2A is a front view of the exhaust pipe of the second embodiment. 2B and 2C are side views of the exhaust pipe of the second embodiment. FIG. 2D is a 2D-2D cross-sectional view of the exhaust pipe of the second embodiment. FIG. 3A is a front view of an exhaust pipe of a third embodiment. 3B and 3C are side views of the exhaust pipe of the third embodiment. FIG. 3D is a 3D-3D cross-sectional view of the exhaust pipe of the third embodiment. FIG. 4A is a side view of the exhaust pipe of the fourth embodiment. 4B and 4C are cross-sectional views of the exhaust pipe in another embodiment as viewed from the side. FIG. 4D is a side view of the exhaust pipe in another embodiment.

  DESCRIPTION OF SYMBOLS 1 ... exhaust pipe, 2 ... purification part, 3 ... exhaust pipe, 4 ... purification part, 5-8 ... exhaust pipe, 10 ... connection part, 10a ... front area, 11, 12 ... protrusion part, 15 ... connection port, 16 ... upstream, 17 ... upstream, 20 ... purification device, 30 ... connection portion, 30 e ... front area, 31, 32 ... projection, 35 ... connection port, 36 ... upstream portion 40, purification device 50 ... connection portion , 50e: front area, 51 to 54: projection, 55: connection port, 56: upstream portion, 60: connection portion, 61: projection portion, 65: connection port, 66: upstream portion, 70: connection portion, 71, 72 ... Protrusion, 75 ... Connection port, 76 ... Upstream part, 80 ... Connection part, 81, 82 ... Projection part, 85 ... Connection port, 86 ... Upstream part.

  Hereinafter, embodiments of the present disclosure will be described using the drawings. The embodiments of the present disclosure are not limited to the following embodiments at all, and may take various forms within the technical scope of the present disclosure.

First Embodiment
[Description of configuration]
The exhaust pipe 1 of the first embodiment shown in FIGS. 1A to 1D is included in a member that constitutes an exhaust gas flow path that allows the exhaust gas to flow down. As one example, the exhaust gas channel may be mounted on a vehicle and may be for discharging exhaust gas from an engine. Also, as an example, the exhaust gas may be emitted from a gasoline engine or a diesel engine. Of course, the exhaust gas channel may be provided other than the vehicle. In addition, the exhaust gas may be emitted from other than the engine.

  Hereinafter, the direction in which the exhaust gas flows down in the exhaust pipe 1 will be referred to as the flow down direction. Further, the upstream side and the downstream side in the flow path of the exhaust gas are simply referred to as the upstream side and the downstream side. Further, the openings forming the upstream end and the upstream end in the tubular member are referred to as an inlet and an outlet.

  The exhaust pipe 1 is connected to the purification unit 2 located on the downstream side of the exhaust pipe 1. The purification unit 2 is a tubular member. Moreover, the purification | cleaning part 2 becomes cylindrical shape, and the cross section orthogonal to the downflow direction is circular or substantially circular. The inlet of the purification unit 2 is wider than the upstream portion 16 of the exhaust pipe 1 described later. In the purification unit 2, a purification device 20 for purifying the exhaust gas is disposed. The purification device 20 may be, for example, DPF (abbreviation of Diesel Particulate Filter), DOC (abbreviation of Diesel Oxidation Catalyst), SCR (abbreviation of Selective Catalytic Reduction), or the like. The purification device 20 is cylindrical.

The exhaust pipe 1 has a connecting portion 10 and an upstream portion 16 which are tubular members, and two projecting portions 11 and 12.
The connection portion 10 is connected to the downstream side of the upstream portion 16. The connection unit 10 is connected to the upstream side of the purification unit 2 and connects the upstream unit 16 and the purification unit 2. That is, the connection unit 10 causes the exhaust gas flowing down from the upstream unit 16 to flow down to the purification unit 2. In the first embodiment, the shape of the connection portion 10 is, for example, a right conical shape, and the diameter of the connection portion 10 becomes larger toward the downstream side (in other words, the width becomes wider). In addition, the inlet and the outlet of the connection portion 10 are both circular or substantially circular. And the outlet is larger than the inlet.

  The upstream portion 16 is connected to the upstream side of the connection portion 10. The upstream portion 16 has a constant or substantially constant width. In the first embodiment, the upstream portion 16 has a cylindrical shape as an example. Here, the boundary between the region inside the upstream portion 16 and the region inside the connection portion 10 is referred to as a connection port 15. The upstream portion 16 linearly extends from the connection port 15 toward the upstream side. Hereinafter, the extending direction of the upstream portion 16 will be referred to as an extending direction. The extension direction is a direction orthogonal to or substantially orthogonal to the connection port 15.

  The two projecting portions 11 and 12 are located in the vicinity of the connection port 15 on the inner wall of the connection portion 10. Here, a region where each protrusion on the inner wall of the connection portion 10 is provided is referred to as a protrusion region. The projecting area is located along the edge of the connection port 15 with a part of the edge (in other words, the upstream edge). In other words, a part of the edge of the projecting area is aligned with the edge of the connection port 15. The two projecting portions 11 and 12 may be provided at positions away from the connection port 15 in the inner wall of the connection portion 10. Further, for example, not only in the vicinity of the connection port 15 but also the two protrusions 11 and 12 may be disposed at a position near the inlet on the inner wall of the connection section 10.

  The two projecting portions 11 and 12 face each other in the width direction of the connecting portion 10 across the region inside the connecting portion 10 (in other words, the flow path of the exhaust gas). More specifically, the two protrusions 11 and 12 face each other across the center line of the connection portion 10. The center line is an imaginary straight line passing through the centers of the openings forming the opposite ends of the connection portion 10.

  Here, the direction in which each of the two projecting portions 11 and 12 protrudes is taken as a protruding direction. The projecting direction is a direction from the inner wall of the connection portion 10 toward the center in the width direction of the connection portion 10. Further, the projecting direction is a direction that intersects with the flow-down direction of the exhaust gas at the connection portion 10. The two projecting portions 11 and 12 are obtained by curving the inner wall of the connecting portion 10 in the projecting direction. The two protrusions 11 and 12 may have the same shape.

Further, in each of the two projecting portions 11 and 12, a direction from the top to the root side is taken as a guiding direction. The guiding direction is opposite to the projecting direction.
As shown in FIG. 1D, each of the two protrusions 11 and 12 has a streamlined cross section along the flow-down direction of the exhaust gas. In other words, the cross section along the flow-down direction of the two protrusions 11 and 12 has the same shape as the upper portion of the blade cross section. For this reason, the exhaust gas flowing down near the two protrusions 11 and 12 does not separate from the protrusions, and flows down along the protrusions. In other words, the two protrusions 11 and 12 have a shape that prevents the exhaust gas flowing down along the protrusions from being separated from the protrusions. As a result, the exhaust gas that has flowed into the area adjacent to the downstream side of each of the two protrusions 11 and 12 has its path inclined in the guiding direction of the protrusions.

  Further, in the area inside the connection portion 10, the area through which the connection port 15 passes when the connection port 15 is moved to the downstream side along the extension direction is taken as a front area 10a. The tops of the two projections 11, 12 reach the front area 10a. That is, the top of each of the two protrusions 11 and 12 faces the connection port 15 along the extension direction. The top of both or one of the two protrusions 11 and 12 may not reach the front area 10a.

[effect]
(1) According to the exhaust pipe 1 of the first embodiment, the exhaust gas flowing down the vicinity of the two protrusions 11 and 12 does not separate from the protrusions but flows down along the protrusions. For this reason, the exhaust gas that has flowed into the area adjacent to the downstream side of the projecting portion has its path inclined in the induction direction. As a result, on the downstream side of the two projecting portions 11 and 12 in the connection portion 10, the exhaust gas is diffused to the outside of the flow path. This makes it possible to flow the exhaust gas into the purification device 20 in a more uniform state. Therefore, the exhaust gas can be made to flow into the purification device 20 so that the purification action of the purification device 20 is sufficiently exhibited.

Further, since the cross sections along the flow-down direction of the two protrusions 11 and 12 are streamlined, it is possible to suppress an increase in pressure loss when the exhaust gas flows down the exhaust pipe 1.
(2) Further, in the first embodiment, the two projecting portions 11 and 12 are provided in the vicinity of the connection port 15 in the inner wall of the connection portion 10. For this reason, at the timing immediately after the exhaust gas enters the connection portion 10, the path of the exhaust gas is adjusted. Therefore, the flow of exhaust gas in the connection portion can be adjusted more suitably. Therefore, the exhaust gas can be made to flow into the purification device 20 so that the purification action of the purification device 20 is sufficiently exhibited.

  (3) Also, in the first embodiment, the tops of the two protrusions 11 and 12 reach the front area 10 a of the connection port 15. For this reason, the course of more exhaust gas can be inclined in the induction direction at the connection portion 10. Therefore, the exhaust gas can be made to flow into the purification device 20 so that the purification action of the purification device 20 is sufficiently exhibited.

Second Embodiment
[Description of configuration]
The exhaust pipe 3 of 2nd Embodiment shown to FIG. 2A-2D is contained in the member which comprises an exhaust gas flow path similarly to 1st Embodiment. The exhaust pipe 3 is connected to the purification unit 4 located on the downstream side of the exhaust pipe 3. The purification unit 4 is a tubular member, and the purification device 40 similar to that of the first embodiment is disposed. The purification section 4 has a rectangular cross section orthogonal to the flow-down direction (more specifically, a rounded rectangle), and is wider than the upstream portion 36 of the exhaust pipe 3 described later. Hereinafter, the longitudinal direction and the latitudinal direction of the cross section will be referred to simply as the longitudinal direction and the latitudinal direction, respectively. Specifically, the inlet of the purification unit 4 has a width in the longitudinal direction and the width direction larger than that of the upstream portion 36. However, the width in the longitudinal direction of the inlet of the purification unit 4 may be wider than the width of the upstream portion 36, and the width in the short direction may be smaller than the width of the upstream portion 36. That is, the inlet of the purification unit 4 may be wider than the upstream portion 36 at least in the longitudinal direction. In addition, the shape of the purification device 40 is prismatic like the outer wall of the purification unit 4.

The exhaust pipe 3 has a connecting portion 30 and an upstream portion 36 which are tubular members, and two projecting portions 31 and 32.
The connection portion 30 is connected to the downstream side of the upstream portion 36. The connection unit 30 is connected to the upstream side of the purification unit 4 and connects the upstream unit 36 and the purification unit 4. That is, the connection unit 30 causes the exhaust gas flowing down from the upstream unit 36 to flow down to the purification unit 4. Moreover, the inlet of the connection part 30 is circular or substantially circular. On the other hand, the outlet of the connecting portion 30 has a rectangular shape similar to the inlet of the purifying portion 4.

  For this reason, the connection portion 30 has a rounded square pyramid shape. Therefore, the connecting portion 30 widens in the downstream direction. Moreover, let two parts extended along the short direction in the connection part 30 be the short parts 30a and 30c. The two short parts 30a, 30c face in the longitudinal direction. Moreover, let two parts extended along the longitudinal direction in the connection part 30 be the longitudinal parts 30b and 30d. The two longitudinal portions 30b and 30d face in the lateral direction.

  The upstream portion 36 is connected to the upstream side of the connection portion 30 and has the same configuration as the upstream portion 16 of the first embodiment. Here, the boundary between the region inside the upstream portion 36 and the region inside the connection portion 30 is referred to as a connection port 35. The upstream portion 36 extends upstream from the connection port 35 in the same manner as in the first embodiment.

  The two protrusions 31 and 32 are located in the vicinity of the connection port 35 on the inner wall of the connection portion 30. More specifically, the projecting region provided with each of the two projecting portions 31 and 32 has a part of its edge (in other words, the upstream edge) located along the edge of the connection port 35 Do. In other words, a part of the edge of the projecting area is aligned with the edge of the connection port 35. The two projecting portions 31 and 32 may be provided at positions away from the connection port 35 in the inner wall of the connecting portion 30. Also, for example, not only in the vicinity of the connection port 35, but also the two protrusions 31, 32 may be disposed at a position near the inlet on the inner wall of the connection section 30.

  The two protrusions 31 and 32 are respectively located at the two short parts 30 a and 30 c in the connecting part 30. The two protrusions 31 and 32 face each other in the longitudinal direction across the region inside the connection portion 30 (in other words, the flow path of the exhaust gas). More specifically, the two protrusions 31 and 32 face each other across the center line of the connection portion 30. The center line is a virtual straight line passing through the center of the entrance of the connection 30 and the center of the exit. For this reason, the protrusion direction of the two protrusion parts 31 and 32 turns into a longitudinal direction.

  The two protrusions 31 and 32 are configured in the same manner as the two protrusions 11 and 12 in the first embodiment. That is, the two protrusions 31 and 32 have a streamlined cross section along the flow-down direction. For this reason, in the connection portion 30, the exhaust gas flowing down the vicinity of the two protrusions 31, 32 is diffused to the outside of the flow path of the exhaust gas on the downstream side of the protrusions. The two protrusions 31 and 32 may have the same shape.

  Also, the top of each of the two protrusions 31, 32 reaches the front area 30 e in the area inside the connection 30. The front area 30e is determined in the same manner as in the first embodiment. That is, the tops of these face the connection port 35 in the flow-down direction. The top of both or one of the two protrusions 31, 32 may not reach the front area 30e.

[effect]
According to the exhaust pipe 3 of the second embodiment, the same effects as (1) to (3) in the first embodiment can be obtained.

Third Embodiment
[Description of configuration]
Although the exhaust pipe 5 of 3rd Embodiment shown to FIG. 3A-3D is comprised similarly to 2nd Embodiment, the structure of a protrusion part differs from 2nd Embodiment. In the following, differences from the second embodiment will be mainly described.

  The exhaust pipe 5 of the third embodiment has a connection portion 50 and an upstream portion 56. The upstream portion 56 is configured in the same manner as the upstream portion 36 of the second embodiment. Moreover, the connection part 50 is comprised similarly to the connection part 30 of 2nd Embodiment, and is connected with the purification part 4 similar to 2nd Embodiment. The connection part 50 has two short parts 50a and 50c and two long parts 50b and 50d similar to the second embodiment. However, the connecting portion 50 is different from the connecting portion 30 of the second embodiment in that the connecting portion 50 has four projecting portions 51 to 54.

  The four protrusions 51 to 54 are located in the vicinity of the connection port 55 on the inner wall of the connection unit 50. More specifically, the projecting region provided with each of the four projecting portions 51 to 54 has a portion of its edge (in other words, the upstream edge) located along the edge of the connection port 55 Do. In other words, a part of the edge of the projecting area is aligned with the edge of the connection port 55. The four projecting portions 51 to 54 may be provided at positions away from the connection port 55 on the inner wall of the connecting portion 50. Further, for example, not only in the vicinity of the connection port 55, but also the four protrusions 51 to 54 may be disposed at a position near the inlet on the inner wall of the connection section 50.

  Each of the four projecting regions is located in a state of crossing the boundary between the short side and the long side. That is, each of the four projecting regions is located at the rounded corner portion of the substantially square pyramidal connecting portion 50. Here, a direction diagonally crossing the outlet of the connection portion 50 is taken as a diagonal direction. The protruding directions of the four protruding portions 51 to 54 are diagonal directions.

  Moreover, two protrusion parts 51 and 54 among the four protrusion parts 51-54 face the diagonal direction on both sides of the area | region inside the connection part 50 (in other words, the flow path of waste gas). More specifically, the two protrusions 51 and 54 face each other across the center line of the connection portion 50. The remaining two protrusions 52, 53 also face diagonally in the same manner.

  The four protrusions 51 to 54 are configured in the same manner as the two protrusions of the first and second embodiments. That is, as for the four protrusion parts 51-54, the cross section which followed the flow-down direction becomes streamline shape. Therefore, in the connection portion 50, the exhaust gas flowing down near the four protrusions 51 to 54 is diffused to the outside of the flow path of the exhaust gas on the downstream side of the protrusions. The four protrusions 51 to 54 may have the same shape.

  In addition, the top of each of the four protrusions 51 to 54 reaches the front area 50 e in the area inside the connection 50. The front area 50e is determined in the same manner as in the first and second embodiments. That is, the tops of these face the connection port 55 along the flow-down direction. The tops of all or part of the two protrusions 51 to 54 may not reach the front area 50 e.

[effect]
According to the exhaust pipe 5 of the third embodiment, the same effect as (1) to (3) in the first and second embodiments can be obtained.

Fourth Embodiment
[Description of configuration]
Although the exhaust pipe 6 of 4th Embodiment shown to FIG. 4A is comprised similarly to 1st Embodiment, the structure of a protrusion part differs from 1st Embodiment. In the following, differences from the first embodiment will be mainly described.

  The exhaust pipe 6 of the fourth embodiment has a connection portion 60 and an upstream portion 66. The upstream portion 66 is configured in the same manner as the upstream portion 16 of the first embodiment. The connection portion 60 is configured in the same manner as the connection portion 10 of the first embodiment, but differs from the connection portion 10 of the first embodiment in that it has one protrusion 61.

  The protruding portion 61 is disposed in a state of laterally surrounding the region inside the connection portion 60 (in other words, the flow path of the exhaust gas). In other words, the protrusion 61 makes a round of the inner wall of the connection portion 60 along the direction intersecting with the flow-down direction of the exhaust gas. The protruding portion 61 is located in the vicinity of the connection port 65 on the inner wall of the connection portion 60. More specifically, in the projecting area provided with the projecting portion 61, a part of the edge (in other words, the upstream edge) is located along the edge of the connection port 65. In other words, a part of the edge of the projecting area is aligned with the edge of the connection port 65. The projecting portion 61 may be provided at a position away from the connection port 65 on the inner wall of the connecting portion 60. Further, for example, the projecting portion 61 may be disposed at a position near the inlet on the inner wall of the connecting portion 60 without limiting to the vicinity of the connection port 65.

  The protrusion part 61 is comprised similarly to the protrusion part of 1st-3rd embodiment. That is, the protrusion 61 has a streamlined cross section along the flow-down direction. For this reason, in the connection portion 60, the exhaust gas flowing down the vicinity of one protrusion 61 is diffused to the outside of the flow path of the exhaust gas on the downstream side of the protrusion.

  Also, the top of the protrusion 61 reaches the front area in the area inside the connection 60. The front area is defined in the same manner as in the first to third embodiments. That is, the tops of these face the connection port 65 along the flow-down direction. The top of the protrusion 61 may not reach the front area.

[effect]
According to the exhaust pipe 6 of the fourth embodiment, the same effect as (1) to (3) in the first to third embodiments can be obtained.

  Moreover, in the fourth embodiment, one protrusion 61 is provided in a state of surrounding the flow path of the exhaust gas from the side. Therefore, the exhaust gas flowing down the edge of the connection portion 60 has its path inclined outward after entering the connection portion 60. That is, it is possible to diffuse the path of the exhaust gas to the outside at the connection portion 60. This makes it possible to flow the exhaust gas into the purification device 20 in a more uniform state.

[Other embodiments]
(1) At least one protrusion in the exhaust pipe of the first to fourth embodiments is configured by curving the connection portion in the protrusion direction. However, the present invention is not limited to this, and for example, at least one protrusion may be configured by arranging an object in the protrusion area.

(2) In the first to fourth embodiments, at least one protrusion is provided in the vicinity of the connection port on the inner wall of the connection portion.
However, for example, as shown in FIG. 4B, in the exhaust pipe 7, two protrusions 71 and 72 may be provided on the inner wall of the connection portion 70 and the upstream portion 76 at a position intersecting the connection port 75. In addition, the exhaust pipe 7 has the connection part 70 and the upstream part 76 similar to 1st Embodiment. In other words, the projecting region in which each of the two projecting portions 71 and 72 is provided may be provided across the connection portion 70 and the inner wall of the upstream portion 76 in a state of intersecting the connection port 75.

  Further, for example, as shown in FIG. 4C, in the exhaust pipe 8, the two projecting portions 81 and 82 may be provided in the vicinity of the connection port 85 in the inner wall of the upstream portion 86. The exhaust pipe 8 has a connecting portion 80 and an upstream portion 86 similar to those of the first embodiment. At this time, a part (in other words, the edge on the downstream side) of the projecting area where the two projecting parts 81 and 82 are provided is in a state along the connection port 85. In other words, a part of the edge of the projecting area is aligned with the connection port 85.

  Also in the second to fourth embodiments, at least one protrusion may be provided in a state of crossing the connection port. Similarly, at least one protrusion may be provided in the vicinity of the connection port on the inner wall of the upstream portion.

  In addition, at least one protrusion may be provided at a position away from the connection port on the inner wall of the upstream portion. Even in such a case, the path of the exhaust gas that has entered the area adjacent to the downstream side of the protrusion inclines in the guiding direction of the protrusion. As a result, the path after the exhaust gas flows into the connecting portion can be inclined in the guiding direction.

Further, the plurality of projecting portions may be provided at at least two of the position intersecting the connection port, the inner wall of the connecting portion, and the inner wall of the upstream portion.
In addition, also when arrange | positioning at least one protrusion part in the position mentioned above, you may provide this protrusion part in the state which enclosed the flow path of exhaust gas from the side similarly to 4th Embodiment.

  (3) In the exhaust pipe of the first and second embodiments, the two projecting portions are provided in the state of facing in the width direction. Further, in the exhaust pipe of the third embodiment, four projecting portions are provided facing each other in the width direction. However, the number and position of the protrusions are not limited to the contents described above.

  Specifically, for example, as shown in FIG. 4D, in the exhaust pipe 1 of the first embodiment, it is assumed that the bent upstream portion 17 is used instead of the linearly extending upstream portion 16. In such a case, the exhaust gas may flow into the connection portion 10 in a state of being biased toward the outer peripheral side of the upstream portion 17. For this reason, one projecting portion 11 similar to that of the first embodiment may be provided on the inner wall of the inner circumferential side of the upstream portion 17 in the connecting portion 10. Thus, in the connection portion 10, the path of the exhaust gas flowing down the inner peripheral side of the upstream portion 17 is inclined to the inner peripheral side. That is, in the connection portion 10, the exhaust gas is diffused to the inner peripheral side. For this reason, it becomes possible to make the exhaust gas which flows down connection part 10 flow in purification device 20 more uniformly.

  (4) In the first to fourth embodiments, the projecting portion is provided for the purpose of causing the exhaust gas flowing down the connection portion to more uniformly flow into the purification device. However, there is also a purifier in which a higher purification action can be obtained when a large amount of exhaust gas is introduced from a partial area (hereinafter referred to as a specific area) of the inlet of the purification section. In the case of using such a purification device, it is preferable to provide one or more projections so as to direct the flow-down direction of the exhaust gas to a specific region.

(5) The shapes, positions, orientations, and the like of the upstream portion, the connection portion, and the purification portion are not limited to the contents exemplified in the first to fourth embodiments, and can be variously determined according to the situation. .
As a specific example, the upstream portion may not have a certain width. Also, the upstream portion may be curved or bent. Further, the upstream portion may extend from the connection port of the connection portion in a direction different from that of the first to fourth embodiments. In addition, the shape of the purification portion may be wider at the inlet than at the upstream portion at least in a predetermined direction. The upstream portion and the purification portion may have the same width.

  In addition, the connection portion can have various shapes according to the shape and position of the upstream portion or the purification portion. Specifically, as in the first to fourth embodiments, the connecting portion may have a shape extending linearly while widening the width. The connection may also be shaped to extend along a curved path while widening.

  And, even if the shape of the upstream part, the connection part, or the purification part is different from the first to fourth embodiments, the position, the number, the shape, etc. of at least one protrusion should be properly determined. Thus, the course of the exhaust gas flowing down the connection can be suitably adjusted. In the case where the upstream portion is curved or the like, the extending direction may be a direction in which a linear section including the outlet of the upstream portion extends. Then, based on the extension direction, the front area may be determined as in the first to fourth embodiments. In addition, when a plurality of protrusions are provided, it may be individually determined whether or not the top reaches the front area for each protrusion. This makes it possible to allow the exhaust gas to flow uniformly into the purification device, or to cause the exhaust gas to flow into the purification device in a state of being biased to the above-described specific region.

Claims (2)

An exhaust pipe for letting down the exhaust gas,
A tubular upstream section which allows the exhaust gases to flow down;
A tubular portion which allows the exhaust gas to flow down, and a connecting portion connected to the downstream side of the upstream portion;
And a plurality of protrusions projecting in different directions from different positions of the inner wall of the connection portion,
A tubular portion where the exhaust gas purification device is disposed, wherein the upstream opening has a shape extending in the longitudinal direction and a portion having a portion wider than the upstream portion is a purification portion.
The connection part is connected to the purification part located downstream of the connection part,
In each of the projecting portions, a direction from the top to the root side is a guiding direction,
Each of the projecting portions has a streamlined cross-section along the flow-down direction of the exhaust gas so that the path of the exhaust gas flowing into the region adjacent to the downstream side of the projecting portion is inclined in the induction direction. Curved and
The boundary between the region inside the upstream portion and the region inside the connection portion is a connection port,
An area in which the plurality of projections are provided on the inner wall is a projection area,
The projecting area is provided on the downstream side of the connection port such that a part of the edge is located along the connection port,
The section including the downstream end of the upstream portion extends in a straight extension direction,
An area through which the connection port passes when the connection port is moved downstream along the extension direction is a front area,
Each of the projections has its top end reaching the front area and faces the other projections in the longitudinal direction. In the exhaust pipe according to claim 1 ,
The plurality of protrusions are provided in a state of laterally surrounding the flow path of the exhaust gas.

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