JP2007032555A - Exhaust pipe assembly structure - Google Patents

Abstract

An exhaust pipe assembly structure capable of improving the degree of freedom of layout is provided.
SOLUTION: A first exhaust pipe 8 and a second exhaust pipe 10 that communicate with a plurality of exhaust ports 2 provided in an engine 1 and outside air, a first exhaust pipe 8 that communicates with the exhaust port 2, and a first exhaust pipe. 8, a first expansion chamber 12 that communicates with the second exhaust pipe 10, a second expansion chamber 14 that communicates with the second exhaust pipe 10, a merge chamber 16 having a discharge pipe 30 that communicates with outside air, a first expansion chamber 12, and a merge chamber 16. And a second additional pipe 20 that communicates the second expansion chamber 14 and the merging chamber 16, and the first exhaust pipe 8 is located from the center position of the vehicle body 6 in the lateral direction of the vehicle. Are arranged eccentrically on the right side in the vehicle left-right direction, and the second exhaust pipe 10 is arranged eccentrically on the left side in the vehicle left-right direction with respect to the center position of the vehicle body 6 in the vehicle left-right direction. The second exhaust pipe 10, the first additional pipe 18, and the second additional pipe 20 have the same pipe length and opening area. It is formed so as to.
[Selection] Figure 1

Description

  The present invention relates to an exhaust pipe assembly structure capable of improving, for example, layout flexibility.

2. Description of the Related Art Conventionally, for example, an engine having a plurality of exhaust ports is mounted in front of a vehicle, and an exhaust pipe that exhausts engine exhaust to the outside air is attached to the rear of the vehicle. An exhaust passage is provided.
As an exhaust pipe assembly structure provided with such an exhaust passage, for example, there is an exhaust pipe assembly structure described in Patent Document 1. In this exhaust pipe assembly structure, the exhaust passage has two exhaust pipes communicating with the engine and a junction pipe communicating these exhaust pipes and exhaust pipes. The two exhaust pipes and the merging pipe are attached to the center position in the left-right direction of the vehicle under the floor of the vehicle body, and the merging pipe is arranged at a position closer to the engine than the exhaust pipe.
Japanese Patent No. 3151965 (FIG. 1)

However, in the exhaust pipe assembly structure described in Patent Document 1, the two exhaust pipes and the merging pipe are attached to the center position in the left-right direction of the vehicle under the floor of the vehicle body, and the merging pipe is closer to the engine side than the exhaust pipe. Therefore, the space in the passenger compartment is reduced and the degree of freedom in layout is reduced. In addition, since a gasoline tank or the like is disposed at the center position of the vehicle body in the left-right direction of the vehicle, it is difficult to attach the exhaust passage to the center position of the vehicle body in the left-right direction of the vehicle, reducing the degree of freedom in layout. End up.
The present invention has been made paying attention to the above problems, and it is an object of the present invention to provide an exhaust pipe assembly structure capable of improving the degree of freedom of layout by making the structure of the exhaust passage appropriate. And

In order to solve the above problems, the present invention is an exhaust pipe assembly structure including an exhaust passage that communicates a plurality of exhaust ports provided in an engine and outside air,
The exhaust passage communicates with at least one of the plurality of discharge ports, and is disposed eccentrically on one side of the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body; Of the plurality of exhaust ports, the exhaust port communicates with an exhaust port other than the exhaust port that communicates with the first exhaust pipe, and is eccentrically arranged on the other side in the vehicle left-right direction with respect to the center position in the vehicle left-right direction of the vehicle body. A second exhaust pipe, a first expansion chamber communicating with the first exhaust pipe, a second expansion chamber communicating with the second exhaust pipe, a merge chamber having a discharge pipe communicating with the outside air, and the first A first additional pipe that communicates the expansion chamber and the merge chamber; and a second additional pipe that communicates the second expansion chamber and the merge chamber;
The first exhaust pipe and the second exhaust pipe have the same pipe length and opening area,
The first additional pipe and the second additional pipe provide an exhaust pipe assembly structure in which a pipe length and an opening area are the same.

  According to the present invention, the exhaust passage can be divided into two passages. For example, these exhaust passages can be arranged eccentrically on the left side and the right side of the center position of the vehicle body in the left-right direction of the vehicle. This makes it possible to secure a space at the center position of the vehicle body in the left-right direction of the vehicle. As a result, layout flexibility can be improved.

Embodiments of the present invention will be described below with reference to the drawings.
First, the configuration of the first embodiment of the present invention will be described with reference to FIGS. 1 to 3.
As shown in FIG. 1, the exhaust pipe assembly structure of the first embodiment of the present invention includes an exhaust passage 4 that allows a plurality of exhaust ports 2 provided in the engine 1 to communicate with outside air.
The engine 1 is a V-type 8-cylinder engine, and four discharge ports 2 are provided on the right and left sides of the vehicle body 6 in the left-right direction of the vehicle. In the present embodiment, a V-type 8-cylinder engine is used as an example of the engine 1, but the configuration of the engine 1 is not limited to this.

The exhaust passage 4 includes a first exhaust pipe 8 and a second exhaust pipe 10, a first expansion chamber 12 and a second expansion chamber 14, a merging chamber 16, a first additional pipe 18, and a second additional pipe 20. ing.
The first exhaust pipe 8 and the second exhaust pipe 10 are formed of a cylindrical pipe, and are formed so that the pipe line length and the opening area are the same.
The first exhaust pipe 8 is arranged eccentrically on the right side in the vehicle left-right direction from the center position of the vehicle body 6 in the vehicle left-right direction, and has four exhaust ports 2 provided on the right side in the vehicle left-right direction of the engine 1. The first branch part 22 communicates with the first branch part 22 and the first collecting part 24 communicates with the first branch part 22.

The second exhaust pipe 10 is arranged eccentrically on the left side in the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body 6, and has four exhaust ports 2 provided on the left side in the vehicle left-right direction of the engine 1. The second branch portion 26 communicates with the second branch portion 26 and the second collecting portion 28 communicates with the second branch portion 26.
The first expansion chamber 12 and the second expansion chamber 14 are hollow boxes that are airtightly isolated from the outside, and have a function of reducing noise that occurs with the exhaust operation of the engine 1. The first expansion chamber 12 communicates with the first exhaust pipe 8 and is smaller than the second expansion chamber 14. The second expansion chamber 14 communicates with the second exhaust pipe 10.

  The merge chamber 16 is a hollow box that is airtightly isolated from the outside, and has a function of reducing noise generated by the exhaust operation of the engine 1, similarly to the first expansion chamber 12 and the second expansion chamber 14. Have. The merge chamber 16 is formed of a cylindrical tube and has a discharge tube 30 that communicates with the outside air. The merge chamber 16 and the first expansion chamber 12 are integrally formed so that the outer peripheral surface shape thereof is the same as the outer peripheral surface shape of the second expansion chamber 14. The space formed in this is the same shape as the space formed in the second expansion chamber 14. Further, the merge chamber 16 and the first expansion chamber 12 are hermetically separated by a partition wall 32.

  The first additional pipe 18 is formed of a cylindrical pipe and communicates the first expansion chamber 12 and the merge chamber 16. The first expansion chamber 12 side of the first additional pipe 18 is inserted into the first expansion chamber 12, and one bending portion 34 is provided in the inserted portion. In the curved portion 34, the interval between the opening end 18 a of the first additional pipe 18 on the first exhaust pipe 8 side and the opening end 8 a of the first exhaust pipe 8 on the first expansion chamber 12 side is such that the first additional pipe 18 protrudes. When the curved portion 34 is not provided in the portion, that is, when the first additional pipe 18 is linear, the distance between the opening end 18a of the first additional pipe 18 and the opening end 8a of the first exhaust pipe 8 Is also formed to be large. Further, as shown in FIGS. 1 and 2, the central axis CLa of the first additional pipe 18 and the central axis CLe of the discharge pipe 30 are at different positions in the vehicle left-right direction and the vehicle vertical direction as seen from the vehicle front-rear direction. Has been placed. That is, the central axis CLa of the first additional pipe 18 and the central axis CLe of the discharge pipe 30 are eccentric from each other.

The second additional pipe 20 is formed of a cylindrical pipe and communicates the second expansion chamber 14 and the merge chamber 16. The center axis CLc of the second additional pipe 20 is eccentric and orthogonal to the center axis CLe of the discharge pipe 30.
The first additional pipe 18 and the second additional pipe 20 have the same pipe length and opening area, and the total area of the opening area of the first additional pipe 18 and the opening area of the second additional pipe 20. However, it is formed to be less than the opening area of the discharge pipe 30.

  As shown in FIG. 3, the first additional pipe 18, the second additional pipe 20, and the discharge pipe 30 have a distance L <b> 1 between the first additional pipe 18 and the discharge pipe 30 of the second additional pipe 20 and the discharge pipe 30. The extension pipe 36 is attached so that the length in each merging chamber 16 is extended to be equal to the distance L2. In the drawing, the extension pipe 36 attached to the first additional pipe 18 is called an extension pipe 36a, the extension pipe 36 attached to the second additional pipe 20 is called an extension pipe 36b, and the extension pipe 36 attached to the discharge pipe 30 is shown. The extension pipes 36c are indicated by broken lines.

Next, functions and effects of this embodiment will be described.
When the engine 1 is driven, the exhaust discharged from each discharge port 2 along with the exhaust operation of the engine 1 passes through the first branch portion 22 and the second branch portion 26, and in the first collecting portion 24 and It moves into the second collecting portion 28 and flows into the first expansion chamber 12 and the second expansion chamber 14. That is, the exhaust gas discharged from each exhaust port 2 in accordance with the exhaust operation of the engine 1 passes through the first exhaust pipe 8 and the second exhaust pipe 10 to pass through the first expansion chamber 12 and the second expansion chamber. 14 flows in.

  The exhaust gas flowing into the first expansion chamber 12 is reduced in volume in the first expansion chamber 12 by the noise reduction function of the first expansion chamber 12 and then passes through the first additional pipe 18 to enter the merge chamber 16. Flow into. The exhaust gas flowing into the second expansion chamber 14 is reduced in volume in the second expansion chamber 14 by the noise reduction function of the second expansion chamber 14, and then passes through the second additional pipe 20 to enter the merge chamber 16. Flow into. Exhaust gas flowing from the first expansion chamber 12 through the first additional pipe 18 and flowing into the merge chamber 16 and exhaust gas flowing from the second expansion chamber 14 through the second additional pipe 20 and into the merge chamber 16 are After merging in the merging chamber 16, it passes through the discharge pipe 30 and is discharged to the outside air.

  Therefore, in the exhaust pipe assembly structure of the present embodiment, the first exhaust pipe 8 is arranged at a position on the right side in the vehicle left-right direction of the vehicle body 6 with respect to the vehicle left-right center position, and the second exhaust pipe 10 is The vehicle body 6 is disposed at a position on the left side in the vehicle left-right direction with respect to the center position in the vehicle left-right direction. For this reason, it is possible to secure a space at the center position of the vehicle body 6 in the left-right direction of the vehicle, and to improve the degree of freedom of layout.

  Further, in the exhaust pipe assembly structure of the present embodiment, the first exhaust pipe 8 and the second exhaust pipe 10 have the same pipe length and opening area, and the first additional pipe 18 and the second additional pipe 20 are pipes. The path length and opening area are the same. Therefore, the exhaust gas that has flowed from the first expansion chamber through the first additional pipe 18 into the merge chamber 16 and the exhaust gas that has flowed from the second expansion chamber 14 through the second additional pipe 20 and has flowed into the merge chamber 16. However, the occurrence of exhaust interference in the merge chamber 16 is prevented, and the exhaust efficiency of the engine 1 is improved.

Furthermore, in the exhaust pipe assembly structure of the present embodiment, since the central axis CLa of the first additional pipe 18 is eccentric with respect to the central axis CLe of the discharge pipe 30, the first additional pipe 18 and the discharge pipe 30 are used. And the noise reduction function of the merging chamber 16 is improved. This is because the noise reduction function is improved when the distance between the exhaust inlet and the exhaust outlet is increased.
Further, in the exhaust pipe assembly structure of the present embodiment, the curved portion 34 is provided in the portion inserted into the first expansion chamber 12 of the first additional pipe 18, so that the inside of the merging chamber 16 having a small volume. Even in this space, the pipe length of the first additional pipe 18 can be made the same as the pipe length of the first exhaust pipe 8.

In the exhaust pipe assembly structure of the present embodiment, the curved portion 34 causes the opening 18a of the first additional pipe 18 on the first exhaust pipe 8 side and the opening of the first exhaust pipe 8 on the first expansion chamber 12 side. The distance from the end 8a is increased, and the noise reduction function of the first expansion chamber 12 is improved.
Further, in the exhaust pipe assembly structure of the present embodiment, the first additional pipe 18 is provided with only one curved portion 34 in the portion inserted into the first expansion chamber 12. It is possible to reduce the pressure loss that occurs when the exhaust gas passes through the pipe 18, and it is possible to suppress a decrease in exhaust efficiency.

In the exhaust pipe assembly structure of the present embodiment, since the central axis CLc of the second additional pipe 20 is eccentric with respect to the central axis CLe of the discharge pipe 30, the second additional pipe 20 and the discharge pipe 30 are used. And the noise reduction function of the merging chamber 16 is improved.
Further, in the exhaust pipe assembly structure of the present embodiment, the first additional pipe 18 and the second additional pipe 20 have a total area of the opening area of the first additional pipe 18 and the opening area of the second additional pipe 20. It is formed to be less than the opening area of the discharge pipe 30. For this reason, since the amount of exhaust discharged from the merge chamber 16 is larger than the amount of exhaust flowing into the merge chamber 16, the exhaust efficiency can be improved.

  In the exhaust pipe assembly structure of the present embodiment, the extension pipes 36a to 36c are attached to the first additional pipe 18, the second additional pipe 20, and the discharge pipe 30, respectively. A distance L1 from the discharge pipe 30 is equal to a distance L2 between the second additional pipe 20 and the discharge pipe 30. For this reason, the effect of preventing exhaust interference in the merge chamber 16 is improved, and the exhaust efficiency of the engine 1 is further improved.

  Further, in the exhaust pipe assembly structure of the present embodiment, the merge chamber 16 and the first expansion chamber 12 are integrally formed so that the outer peripheral surface shape thereof is the same as the outer peripheral surface shape of the second expansion chamber 14. Therefore, the configuration of the vehicle can be symmetric, and deterioration of the weight balance and rigidity balance can be prevented. Moreover, it becomes possible to prevent the usability in the vehicle interior from being lowered. Furthermore, since the positions of the first expansion chamber 12 and the second expansion chamber 14 in the left-right direction of the vehicle can be changed to arbitrary positions, they can be easily applied to different vehicle types. As a result, the parts can be diverted, and the cost can be reduced.

Further, in the exhaust pipe assembly structure of the present embodiment, the first exhaust pipe 8, the second exhaust pipe 10, the first additional pipe 18, the second additional pipe 20, and the discharge pipe 30 are formed from cylindrical pipes. Therefore, the exhaust gas smoothly passes through each pipe, and it is possible to prevent a decrease in pressure loss in each pipe.
In the exhaust pipe assembly structure of the present embodiment, the first additional pipe 18 and the second additional pipe 20 are formed so that the pipe length and the opening area of the first additional pipe 18 and the second additional pipe 20 are the same. However, the present invention is not limited to this, and the first additional pipe 18 and the second additional pipe 20 are formed so that the opening area of the second additional pipe 20 is less than the opening area of the first additional pipe 18. Also good. In this case, since the amount of exhaust gas flowing into the merge chamber 16 from the first additional pipe 18 is larger than the amount of exhaust gas flowing into the merge chamber 16 from the second additional pipe 20, the inside of the first additional pipe 18 Part of the exhaust that passes through stays in the curved portion 34, so that the amount of exhaust that flows into the merge chamber 16 from the first additional pipe 18 is less than the exhaust that flows into the merge chamber 16 from the second additional pipe 20. Even in this case, it is possible to avoid the effect of exhaust interference being reduced.

Further, in the exhaust pipe assembly structure of the present embodiment, the central axis CLa of the first additional pipe 18 is eccentric with respect to the central axis CLe of the exhaust pipe 30, but the present invention is not limited to this. The central axis CLa of the first additional pipe 18 may be parallel to the central axis CLe of the discharge pipe 30.
Furthermore, in the exhaust pipe assembly structure of the present embodiment, the curved portion 34 is provided at one portion in the portion inserted into the first expansion chamber 12 of the first additional pipe 18, but the present invention is limited to this. It is not a thing. In other words, the curved portion 34 may not be provided in the portion of the first additional pipe 18 that is inserted into the first expansion chamber 12, and the first additional pipe 18 is inserted into the first expansion chamber 12. It is good also as a structure which provided the curved part 34 of the multiple places in the part which has.

Further, in the exhaust pipe assembly structure of the present embodiment, the center axis CLc of the second additional pipe 20 is eccentric with respect to the center axis CLe of the discharge pipe 30, but the present invention is not limited to this. The central axis CLc of the second additional pipe 20 may be parallel to the central axis CLe of the discharge pipe 30.
Further, in the exhaust pipe assembly structure of the present embodiment, the first additional pipe 18 and the second additional pipe 20 are configured such that the total area of the opening area of the first additional pipe 18 and the opening area of the second additional pipe 20 is the discharge pipe. Although it formed so that it might become less than 30 opening areas, it is not limited to this. That is, the first additional pipe 18 and the second additional pipe 20 are formed such that the total area of the opening area of the first additional pipe 18 and the opening area of the second additional pipe 20 is equal to or larger than the opening area of the discharge pipe 30. May be.

  Further, in the exhaust pipe assembly structure of the present embodiment, the extension pipes 36 are attached to the first additional pipe 18, the second additional pipe 20, and the discharge pipe 30, respectively. The extension pipe 36 may not be attached to the pipe 18, the second additional pipe 20, and the discharge pipe 30. Further, the extension pipe 36 may be attached to one or two of the first additional pipe 18, the second additional pipe 20, and the discharge pipe 30.

  Further, in the exhaust pipe assembly structure of the present embodiment, the merge chamber 16 and the first expansion chamber 12 are integrally formed so that the outer peripheral surface shape thereof is the same shape as the outer peripheral surface shape of the second expansion chamber 14, It is not limited to this. That is, the merge chamber 16 and the first expansion chamber 12 may be integrally formed so that the outer peripheral surface shape thereof is different from the outer peripheral surface shape of the second expansion chamber 14. Further, the merge chamber 16 and the first expansion chamber 12 may be formed independently.

  In the exhaust pipe assembly structure of the present embodiment, the first exhaust pipe 8, the second exhaust pipe 10, the first additional pipe 18, the second additional pipe 20, and the discharge pipe 30 are formed from cylindrical pipes. It is not limited. That is, at least one of these tubes may be formed from a cylindrical tube, and all the tubes may be formed by, for example, a tube having a square cross section.

  Further, in the exhaust pipe assembly structure of the present embodiment, the first exhaust pipe 8 is disposed at a position on the right side in the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body 6, and the second exhaust pipe 10 is disposed on the vehicle body 6. However, the positions at which the first exhaust pipe 8 and the second exhaust pipe 10 are disposed are limited to this. is not. In other words, the first exhaust pipe 8 is disposed at a position on the left side of the vehicle left-right direction with respect to the center position of the vehicle body 6 in the left-right direction of the vehicle, and the second exhaust pipe 10 It is good also as a structure arrange | positioned in the position of the right side of the left-right direction.

Next, with reference to FIG.4 and FIG.5, the structure of 2nd embodiment of this invention is demonstrated. In addition, about the structure similar to 1st embodiment mentioned above, the same code | symbol is attached | subjected and demonstrated.
As shown in FIG. 4, the exhaust pipe assembly structure of the present embodiment includes an exhaust passage 4 that allows a plurality of exhaust ports 2 provided in the engine 1 to communicate with outside air.
As in the first embodiment described above, the engine 1 is provided with four discharge ports 2 on the right and left sides of the vehicle body 6 in the left-right direction of the vehicle.

The exhaust passage 4 includes a first exhaust pipe 8 and a second exhaust pipe 10, a first extension chamber 12 and a second extension chamber 14, a first additional pipe 18, a second additional pipe 20, a discharge pipe 30, A junction 38 is provided.
The first exhaust pipe 8 and the second exhaust pipe 10 are formed of a cylindrical pipe, and are formed so that the pipe line length and the opening area are the same.
The first exhaust pipe 8 is arranged eccentrically on the right side in the vehicle left-right direction from the center position of the vehicle body 6 in the vehicle left-right direction, and has four exhaust ports 2 provided on the right side in the vehicle left-right direction of the engine 1. The first branch part 22 communicates with the first branch part 22 and the first collecting part 24 communicates with the first branch part 22.

The second exhaust pipe 10 is arranged eccentrically on the left side in the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body 6, and has four exhaust ports 2 provided on the left side in the vehicle left-right direction of the engine 1. The second branch portion 26 communicates with the second branch portion 26 and the second collecting portion 28 communicates with the second branch portion 26.
The first expansion chamber 12 and the second expansion chamber 14 are hollow boxes that are airtightly isolated from the outside, and have a function of reducing noise that occurs with the exhaust operation of the engine 1. The first expansion chamber 12 and the second expansion chamber 14 are formed so that the outer peripheral surface shapes thereof are the same, and the space formed in the first expansion chamber 12 and the second expansion chamber 14 are formed. The space formed inside has the same shape. The first expansion chamber 12 communicates with the first exhaust pipe 8, and the second expansion chamber 14 communicates with the second exhaust pipe 10.

  The first additional pipe 18 is formed of a cylindrical pipe and communicates the first expansion chamber 12 and the merging portion 38. A curved portion 34 is provided between the open end portions of the first additional pipe 18. The curved portion 34 has an interval between the opening end 18a of the first additional pipe 18 on the first exhaust pipe 8 side and the opening end 8a of the first exhaust pipe 8 on the first expansion chamber 12 side. When the curved portion 34 is not provided between the end portions, that is, when the first additional pipe 18 is linear, the opening end 18a of the first additional pipe 18 and the opening end 8a of the first exhaust pipe 8 It is formed so as to be larger than the interval.

The second additional pipe 20 is formed of a cylindrical pipe and communicates the second expansion chamber 14 and the merging portion 38.
The discharge pipe 30 is formed of a cylindrical pipe, and one opening end is inserted into the joining portion 38 in the first expansion chamber 12, and the other opening end is disposed outside the first expansion chamber 12.
The junction 38 is a hollow box that is airtightly isolated from the outside, and is disposed in the first expansion chamber 12. An opening end 18 b of the first additional pipe 18 on the discharge pipe 30 side and an opening end 20 a of the second additional pipe 20 on the discharge pipe 30 side are inserted into the junction 38. That is, the junction 38 joins the first additional pipe 18 and the second additional pipe 20 to communicate with the discharge pipe 30.

As shown in FIG. 5, the opening end 18 b on the discharge pipe 30 side of the first additional pipe 18 and the opening end 20 a on the discharge pipe 30 side of the second additional pipe 20 are formed in a substantially semicircular shape. In the part 38, it arrange | positions in parallel and merges.
The first additional pipe 18 and the second additional pipe 20 have the same pipe length and opening area, and the opening area of the opening end 18b of the first additional pipe 18 and the opening end of the second additional pipe 20 are the same. The total area with the opening area of 20a is less than the opening area of the discharge pipe 30.
Other configurations are the same as those of the first embodiment described above.

Next, functions and effects of this embodiment will be described.
When the engine 1 is driven, the exhaust discharged from each discharge port 2 along with the exhaust operation of the engine 1 passes through the first branch portion 22 and the second branch portion 26, and in the first collecting portion 24 and It moves into the second collecting portion 28 and flows into the first expansion chamber 12 and the second expansion chamber 14. That is, the exhaust gas discharged from each exhaust port 2 in accordance with the exhaust operation of the engine 1 passes through the first exhaust pipe 8 and the second exhaust pipe 10 to pass through the first expansion chamber 12 and the second expansion chamber. 14 flows in.

  The exhaust gas flowing into the first expansion chamber 12 is reduced in volume in the first expansion chamber 12 by the noise reduction function of the first expansion chamber 12 and then passes through the first additional pipe 18 to enter the junction 38. Flow into. The exhaust gas flowing into the second expansion chamber 14 is reduced in volume in the second expansion chamber 14 by the noise reduction function of the second expansion chamber 14, and then passes through the second additional pipe 20 to enter the junction 38. Flow into. Exhaust gas that flows from the first expansion chamber 12 through the first additional pipe 18 and flows into the merge section 38 and exhaust gas that flows from the second expansion chamber 14 through the second additional pipe 20 and flows into the merge section 38 After joining in the joining part 38, it passes through the inside of the discharge pipe 30 and is discharged to the outside air.

  Therefore, in the exhaust pipe assembly structure of the present embodiment, the exhaust gas that has flowed from the first expansion chamber 12 through the first additional pipe 18 into the junction 38 and the second expansion chamber 14 to the second additional pipe 20. In the exhaust pipe assembly structure of the first embodiment described above, the exhaust gas that has flowed into the merging portion 38 after passing through the vortex merges in the merging portion 38 and then passes through the discharge pipe 30 and is discharged to the outside air. It is possible to prevent the noise reduction effect that may occur from being hindered. This is because in the exhaust pipe assembly structure of the first embodiment described above, when the exhaust gas whose volume is reduced in the first expansion chamber 12 and the exhaust gas whose volume is reduced in the second expansion chamber 14 merge in the merge chamber. This is because the noise reduction effect will be hindered if the pressure fluctuation phases deviate from the opposite phase relationship.

  Further, in the exhaust pipe assembly structure of the present embodiment, the first exhaust pipe 8 and the second exhaust pipe 10 have the same pipe length and opening area, and the first additional pipe 18 and the second additional pipe 20 are pipes. The path length and opening area are the same. Therefore, the exhaust gas that has flowed from the first expansion chamber through the first additional pipe 18 into the merge portion 38 and the exhaust gas that has passed from the second expansion chamber 14 through the second additional tube 20 and has flowed into the merge portion 38. However, the occurrence of exhaust interference in the junction 38 is prevented, and the exhaust efficiency of the engine 1 is improved.

  Furthermore, in the exhaust pipe assembly structure of the present embodiment, the first additional pipe 18 and the second additional pipe 20 have a total area of the opening area of the first additional pipe 18 and the opening area of the second additional pipe 20. It is formed to be less than the opening area of the discharge pipe 30. For this reason, since the amount of exhaust discharged from the confluence 38 is larger than the amount of exhaust flowing into the confluence 38, the exhaust efficiency can be improved.

  Further, in the exhaust pipe assembly structure of the present embodiment, the first expansion chamber 12 and the second expansion chamber 14 are formed so that the outer peripheral surface shapes thereof are the same. It becomes possible to make it symmetrical, and it becomes possible to prevent deterioration of weight balance and rigidity balance. Moreover, it becomes possible to prevent the usability in the vehicle interior from being lowered. Furthermore, since the positions of the first expansion chamber 12 and the second expansion chamber 14 in the left-right direction of the vehicle can be changed to arbitrary positions, they can be easily applied to different vehicle types. As a result, the parts can be diverted, and the cost can be reduced.

Further, in the exhaust pipe assembly structure of the present embodiment, since the merging portion 38 is disposed in the first expansion chamber 12, it is not necessary to secure a space for disposing the merging chamber 38 in the vehicle body 6, and the layout. The degree of freedom can be improved.
Other actions and effects are the same as those of the first embodiment described above.
In the exhaust pipe assembly structure of the present embodiment, the merging portion 38 is disposed in the first expansion chamber 12, but is not limited thereto, and the merging portion 38 is disposed outside the first expansion chamber 12. May be. However, as in the exhaust pipe assembly structure of the present embodiment, it is preferable to arrange the merging portion 38 in the first expansion chamber 12 because the degree of freedom in layout can be improved.

  Further, in the exhaust pipe assembly structure of the present embodiment, the first additional pipe 18 and the second additional pipe 20 are divided into the opening area of the opening end 18 b of the first additional pipe 18 and the opening area of the opening end 20 a of the second additional pipe 20. However, the present invention is not limited to this. That is, the first additional pipe 18 and the second additional pipe 20 are configured such that the total area of the opening area of the opening end 18 b of the first additional pipe 18 and the opening area of the opening end 20 a of the second additional pipe 20 is equal to that of the discharge pipe 30. You may form so that it may become more than an opening area.

It is a figure which shows the structure of the exhaust pipe assembly structure of 1st embodiment of this invention. It is the II-II sectional view taken on the line of FIG. It is a figure which shows the structure of the 1st expansion chamber and merge room of 1st embodiment of this invention. It is a figure which shows the structure of the exhaust pipe assembly structure of 2nd embodiment of this invention. It is the VV sectional view taken on the line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Engine 2 Discharge port 4 Exhaust passage 6 Car body 8 1st exhaust pipe 10 2nd exhaust pipe 12 1st expansion chamber 14 2nd expansion chamber 16 Junction chamber 18 1st additional pipe 20 2nd additional pipe 22 1st branch part 24 1st One collecting portion 26 Second branch portion 28 Second collecting portion 30 Discharge pipe 32 Bulkhead 34 Bending portion 36 Extension tube 38 Merge portion CLa Central axis of first additional pipe CLe Central axis of discharge pipe CLc Central axis of second additional pipe L1 Distance between first additional pipe and discharge pipe L2 Distance between second additional pipe and discharge pipe

Claims (14)

An exhaust pipe assembly structure having an exhaust passage communicating with a plurality of exhaust ports provided in the engine and outside air,
The exhaust passage communicates with at least one of the plurality of discharge ports, and is disposed eccentrically on one side of the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body; Of the plurality of exhaust ports, the exhaust port communicates with an exhaust port other than the exhaust port that communicates with the first exhaust pipe, and is eccentrically arranged on the other side in the vehicle left-right direction with respect to the center position in the vehicle left-right direction of the vehicle body. A second exhaust pipe, a first expansion chamber communicating with the first exhaust pipe, a second expansion chamber communicating with the second exhaust pipe, a merge chamber having a discharge pipe communicating with the outside air, and the first A first additional pipe that communicates the expansion chamber and the merge chamber; and a second additional pipe that communicates the second expansion chamber and the merge chamber;
The first exhaust pipe and the second exhaust pipe have the same pipe length and opening area,
The exhaust pipe assembly structure characterized in that the first additional pipe and the second additional pipe have the same pipe length and opening area. An exhaust pipe assembly structure having an exhaust passage communicating with a plurality of exhaust ports provided in the engine and outside air,
The exhaust passage communicates with at least one of the plurality of discharge ports, and is disposed eccentrically on one side of the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body; Of the plurality of exhaust ports, the exhaust port communicates with an exhaust port other than the exhaust port that communicates with the first exhaust pipe, and is eccentrically arranged on the other side in the vehicle left-right direction with respect to the center position in the vehicle left-right direction of the vehicle body. A second exhaust pipe, a first expansion chamber communicating with the first exhaust pipe, a second expansion chamber communicating with the second exhaust pipe, a merge chamber having a discharge pipe communicating with the outside air, and the first A first additional pipe that communicates the expansion chamber and the merge chamber; and a second additional pipe that communicates the second expansion chamber and the merge chamber;
The first exhaust pipe and the second exhaust pipe have the same pipe length and opening area,
The first additional pipe and the second additional pipe have the same pipe length,
An exhaust pipe assembly structure, wherein an opening area of the second additional pipe is less than an opening area of the first additional pipe.   The exhaust pipe assembly structure according to claim 1 or 2, wherein the central axis of the first additional pipe is eccentric with respect to the central axis of the discharge pipe.   The exhaust pipe assembly structure according to any one of claims 1 to 3, wherein a central axis of the second additional pipe is eccentric with respect to a central axis of the discharge pipe.   At least one of the first additional pipe, the second additional pipe, and the discharge pipe so that the distance between the first additional pipe and the discharge pipe and the distance between the second additional pipe and the discharge pipe are equal in the merge chamber. The exhaust pipe assembly structure according to any one of claims 1 to 4, further comprising an extension pipe attached to extend the pipe length in the merge chamber.   The exhaust pipe assembly structure according to any one of claims 1 to 5, wherein the first expansion chamber and the merging chamber are integrally formed.   The exhaust pipe assembly structure according to claim 6, wherein the outer peripheral surface shape of the integrally formed first expansion chamber and the merge chamber is the same shape as the outer peripheral surface shape of the second expansion chamber. An exhaust pipe assembly structure having an exhaust passage communicating with a plurality of exhaust ports provided in the engine and outside air,
The exhaust passage communicates with at least one of the plurality of discharge ports, and is disposed eccentrically on one side of the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body; Of the plurality of exhaust ports, the exhaust port communicates with an exhaust port other than the exhaust port that communicates with the first exhaust pipe, and is eccentrically arranged on the other side in the vehicle left-right direction with respect to the center position in the vehicle left-right direction of the vehicle body. The second exhaust pipe, the first expansion chamber communicating with the first exhaust pipe, the second expansion chamber communicating with the second exhaust pipe, the first additional pipe communicating with the first expansion chamber, A second additional pipe that communicates with the second expansion chamber, a discharge pipe that communicates with the outside air, and a joining portion that joins the first additional pipe and the second additional pipe to communicate with the discharge pipe,
The first exhaust pipe and the second exhaust pipe have the same pipe length and opening area,
The exhaust pipe assembly structure characterized in that the first additional pipe and the second additional pipe have the same pipe length and opening area. An exhaust pipe assembly structure having an exhaust passage communicating with a plurality of exhaust ports provided in the engine and outside air,
The exhaust passage communicates with at least one of the plurality of discharge ports, and is disposed eccentrically on one side of the vehicle left-right direction with respect to the vehicle left-right center position of the vehicle body; Of the plurality of exhaust ports, the exhaust port communicates with an exhaust port other than the exhaust port that communicates with the first exhaust pipe, and is eccentrically arranged on the other side in the vehicle left-right direction with respect to the center position in the vehicle left-right direction of the vehicle body. The second exhaust pipe, the first expansion chamber communicating with the first exhaust pipe, the second expansion chamber communicating with the second exhaust pipe, the first additional pipe communicating with the first expansion chamber, A second additional pipe that communicates with the second expansion chamber, a discharge pipe that communicates with the outside air, and a joining portion that joins the first additional pipe and the second additional pipe to communicate with the discharge pipe,
The first exhaust pipe and the second exhaust pipe have the same pipe length and opening area,
The first additional pipe and the second additional pipe have the same pipe length,
An exhaust pipe assembly structure, wherein an opening area of the second additional pipe is less than an opening area of the first additional pipe.   The exhaust pipe assembly structure according to claim 8 or 9, wherein the merging portion is disposed in the first expansion chamber.   The exhaust pipe assembly structure according to any one of claims 8 to 10, wherein the outer peripheral surface shapes of the first expansion chamber and the second expansion chamber are the same. The first expansion chamber side of the first additional pipe is inserted into the first expansion chamber, and one or a plurality of curved portions are provided in the inserted portion,
The distance between the opening end on the first expansion chamber side of the first additional pipe and the opening end on the first expansion chamber side of the first exhaust pipe is such that the curved portion is not provided on the first additional pipe. The gap between the end of the first additional pipe on the first expansion chamber side and the end of the first exhaust pipe on the first expansion chamber side is greater than any one of claims 1 to 11. The exhaust pipe assembly structure described in the section.   The total area of the opening area of the first additional pipe and the opening area of the second additional pipe is less than the opening area of the discharge pipe, according to any one of claims 1 to 12. Exhaust pipe assembly structure.   14. At least one of the first exhaust pipe, the second exhaust pipe, the first additional pipe, the second additional pipe, and the discharge pipe is a cylindrical pipe. Exhaust pipe assembly structure described in 1.

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