JP2011043108A - Exhaust device of internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an exhaust device provided downstream in the discharge direction of exhaust gas to an internal combustion engine and having hollow-shaped exhaust system components with an end of one of them joined to the other hollow-shaped exhaust system component. <P>SOLUTION: A part in an extension direction of an exhaust pipe 18 is formed of a PCCP (Pseudo-Cylindrical Concave Polyhedral) shell 23. The PCCP shell 23 includes surfaces of a polygon 24 connected in such an uneven manner that adjacent surfaces of the polygon 24 have a side in common and the side of adjacent surfaces of the polygon 24 forms the ridgeline 24a of a crest or a trough 24b. The polygon 24 is formed with a depth from the top 24c of the crest to the trough 24b in the PCCP shell 23 set to be α<√2t so that the flexural rigidity of the PCCP shell 23 becomes low. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an exhaust device for an internal combustion engine, and in particular, is provided downstream of the internal combustion engine in the exhaust direction of exhaust gas, and the end of one hollow exhaust system component is connected to another hollow exhaust system component. The present invention relates to an exhaust device for an internal combustion engine to be joined.

In general, as an exhaust device provided in an internal combustion engine of a vehicle such as an automobile, exhaust system parts such as a front pipe, a catalytic converter, a center pipe, a muffler, and a tail pipe are connected. Joining by welding is adopted.
By the way, in an exhaust system in which exhaust system parts are joined by welding, in a severe use environment where vibrations are excessively large, the welded part where exhaust system parts are joined together is caused by external input vibration. Tend to concentrate large stresses.

  In particular, when joining exhaust system parts having different outer diameters by welding, the outer shape of the exhaust system part (muffler, catalytic converter, etc.) with the larger outer diameter is, for example, the larger outer diameter. In many cases, one end portion of the exhaust system component is tapered so that one end portion of the exhaust system component having the smaller outer diameter is joined to the one end portion of the exhaust system component having the larger outer diameter by welding.

In this case, the welded part of the exhaust system part is inserted into one end part of one exhaust system part and then the one end part of the other exhaust system part after inserting the one end part of the other exhaust system part. Are often welded.
At this time, one exhaust system component is inserted into one end of the other exhaust system component and the other end of the other exhaust system component is joined to each other, so that one exhaust system component and the other exhaust system component are externally connected at the joint portion. The diameter will change greatly.

  Thus, when the outer diameter changes greatly in the welded part, a large stress tends to concentrate on the welded part, and the durability of the welded part tends to deteriorate. For this reason, for example, when one end of the muffler is joined to one end of the exhaust pipe by welding, a flexible tube is provided in a part of the exhaust pipe in the axial direction in order to prevent stress from concentrating on the welded portion. In this way, stress concentration on the welded portion is relaxed by the flexible tube (see, for example, Patent Document 1).

  In addition, as shown in FIG. 12, when one end of the exhaust pipe 2 is welded to one end of the muffler 1 (the welding portion is indicated by the welded portion 3), a hollow is formed on the inner peripheral surface of the one end of the exhaust pipe 2. The sleeve member 4 is joined by welding to reinforce the welded part.

JP 2004-176664 A

  In such an exhaust system for a conventional internal combustion engine, a flexible tube or a sleeve member 4 is provided in the exhaust pipe in order to alleviate stress concentration at the joint portion of the exhaust system parts. Therefore, the number of parts of the exhaust system parts increases, and there is a problem that the weight of the exhaust system increases and the manufacturing cost of the exhaust system increases.

  The present invention has been made in order to solve the above-described conventional problems, and prevents an increase in the weight of the exhaust device and an increase in the manufacturing cost of the exhaust device while preventing an increase in the exhaust system component. It is possible to provide an exhaust device for an internal combustion engine that can alleviate stress concentration at a joint part of an exhaust system component when external vibration is input to the exhaust part and can improve durability of the joint part. Objective.

  In order to achieve the above object, an exhaust system for an internal combustion engine according to the present invention is (1) provided downstream of the internal combustion engine in the exhaust direction of exhaust gas, and the end of one hollow exhaust system component is hollow. In the exhaust system joined to another exhaust system component in the shape, the one exhaust system component has a multi-faceted structure along a circumferential direction in at least part of the extending direction of the one exhaust system component The polyhedral structure is constituted by adjacent polygonal surfaces that share one side, and one side of the polygonal surfaces is connected in a concavo-convex shape so as to form a ridgeline or valley of a mountain.

  With this configuration, at least a part of the extending direction of one exhaust system component has a polyhedral structure along the circumferential direction of the one exhaust system component, and the polyhedral structure has one side between adjacent polygonal surfaces. The polygonal shape is formed so that one side of the polygonal surfaces is connected in a concave-convex shape so that one side of the polygonal surface forms a ridgeline or valley of a mountain. By setting, when external vibration is input to the exhaust device, the stress input to the exhaust system component due to the external vibration can be distributed to the multi-face structure of one exhaust system component. For this reason, it can relieve | moderate that stress concentrates on the junction part of exhaust system components, and can improve durability of a junction part.

  In addition, since at least a part of one exhaust system part has a multi-face structure, durability of the joining portion can be improved, so that a flexible tube, a sleeve member, and the like can be made unnecessary as in the related art. It is possible to prevent an increase in weight and to prevent an increase in the manufacturing cost of the exhaust device.

  In addition, by making a part of one exhaust system part into a multi-face structure, the elastic vibration of the exhaust system is reduced against the vibration characteristics transmitted from the internal combustion engine to the exhaust system and the vibration characteristics transmitted from the vehicle body to the exhaust system. The vibration characteristics can be adjusted, and resonance between the exhaust device and the internal combustion engine or the vehicle body can be prevented.

  In the exhaust system for an internal combustion engine according to the above (1), (2) the polyhedral structure has a depth from a peak to a valley formed by one side of the polygonal surface as α, When the plate thickness is t, α <√2 · t.

  With this configuration, α <√2 · t, where α is the depth from the top of the mountain formed by one side of the polygonal surface to the valley, and t is the thickness of the polyhedral structure. Compared to a hollow pipe having a uniform outer diameter in the direction, the cross-sectional secondary moment of the polyhedral structure can be reduced, and the bending rigidity of the polyhedral structure can be reduced.

  In the exhaust system for an internal combustion engine according to the above (1) or (2), (3) the other exhaust system component is constituted by a muffler or a catalytic converter, and the one exhaust system component is the muffler or the catalyst. It is comprised from the exhaust pipe with which the edge part of a converter is joined.

  With this configuration, when external vibration is input to the exhaust pipe, the catalytic converter, and the exhaust pipe, the stress input to the exhaust pipe, the catalytic converter, and the muffler due to the external vibration can be dispersed in the multi-face structure of the exhaust pipe. For this reason, it is possible to alleviate stress concentration at the joint portion between the muffler and the exhaust pipe or the joint portion between the catalytic converter and the exhaust pipe, and the durability of the joint portion can be improved.

  In the exhaust system for an internal combustion engine according to the above (1) or (2), (4) the other exhaust system component is configured by an exhaust pipe, and the other exhaust system component has an end portion of the exhaust pipe. It consists of a muffler or a catalytic converter to be joined.

  With this configuration, when external vibration is input to the exhaust pipe, the catalytic converter, and the muffler, the stress input to the exhaust pipe, the catalytic converter, and the muffler due to the external vibration can be dispersed in the multi-face structure of the catalytic converter or the muffler. For this reason, it is possible to alleviate stress concentration at the joint portion between the muffler and the exhaust pipe or the joint portion between the catalytic converter and the exhaust pipe, and the durability of the joint portion can be improved.

  In the exhaust system for an internal combustion engine according to (1) or (2), (5) the other exhaust system component includes at least one of an exhaust pipe, a catalytic converter, and a muffler, and the one exhaust system The component is composed of at least one support bracket having one end joined to at least one of the exhaust pipe, the catalytic converter, and the muffler and the other end supported by a support member.

With this configuration, when external vibration is input to the exhaust pipe, the catalytic converter, and the muffler, the stress input to the exhaust pipe, the catalytic converter, and the muffler due to the external vibration can be dispersed in the multi-face structure of the support bracket.
For this reason, it can relieve | moderate that stress concentrates on the junction part of an exhaust pipe, a catalytic converter or a muffler, and a support bracket, and can improve durability of a junction part.

  According to the present invention, when an external vibration is input to the exhaust system component while preventing an increase in the weight of the exhaust system and an increase in the manufacturing cost of the exhaust system, the joint portion of the exhaust system component is prevented. Therefore, it is possible to provide an exhaust device for an internal combustion engine that can alleviate stress concentration and improve durability of the joint portion.

1 is a view showing a first embodiment of an exhaust device for an internal combustion engine according to the present invention, and is a side view of the exhaust device. FIG. 1 is a diagram illustrating a first embodiment of an exhaust device for an internal combustion engine according to the present invention, and is a diagram illustrating a cross section of a main muffler and a part of an exhaust pipe connected to the main muffler. It is a figure which shows 1st Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, and is a front view of a PCCP shell. It is a figure which shows 1st Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, (a) is a figure which shows the cutting | disconnection direction of a PCCP shell, (b) is the cutting | disconnection of the figure (a) It is a figure which shows the cross section of the PCCP shell cut | disconnected by plane AA. It is a figure which shows 1st Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, (a) is a figure which shows the cutting direction of a general hollow pipe, (b) is the figure ( It is a figure which shows the cross section of the hollow pipe cut | disconnected by the cut surface BB of a). 1 is a diagram illustrating a first embodiment of an exhaust device for an internal combustion engine according to the present invention, and is a diagram illustrating a mounting structure for a main muffler and a vehicle body. It is a figure which shows 2nd Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the downstream of a main muffler, and the attachment structure of a vehicle body. It is a figure which shows 2nd Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, and is a top view of the upstream of an exhaust apparatus. It is a figure which shows 2nd Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, and is a front view of the PCCP shell provided in a support bracket. It is a figure which shows 3rd Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, and is a side view of an exhaust apparatus. It is a figure which shows 3rd Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention, and is a figure which shows the cross section of a main muffler and a part of exhaust pipe connected to a main muffler in a cross section. It is a figure which shows the cross section of a conventional muffler, and a part of exhaust pipe connected to a muffler in a cross section.

(First embodiment)
Embodiments of an exhaust device for an internal combustion engine according to the present invention will be described below with reference to the drawings.
FIGS. 1-6 is a figure which shows 1st Embodiment of the exhaust apparatus of the internal combustion engine which concerns on this invention.
First, the configuration will be described.
In FIG. 1, an exhaust device 11 for an internal combustion engine exhausts exhaust gas exhausted from an engine 12 as an internal combustion engine to the outside. From an exhaust system component downstream of the engine 12 in the exhaust direction of exhaust gas It is composed.

  An exhaust manifold 13 is connected to an exhaust port communicating with a combustion chamber provided in a cylinder block of the engine 12. This exhaust manifold 13 is provided inside the engine 12 for a four-cylinder engine, for example. The four combustion chambers are configured to include four branch pipes connected via an exhaust port provided in the cylinder head of the engine 12 and a collecting pipe that collects the branch pipes.

One end of an exhaust pipe 14 constituting a front pipe is connected to the exhaust manifold 13, and one end of a catalytic converter 15 is joined to the other end of the exhaust pipe 14 by welding. The catalytic converter 15 has a built-in three-way catalyst, which is oxidized by carbon monoxide, hydrocarbons, and nitrogen in exhaust gas discharged from the engine 12 through the exhaust manifold 13 and the exhaust pipe 14. It is designed to purify things.
One end of an exhaust pipe 16 constituting a center pipe is joined to the other end of the catalytic converter 15 by welding, and one end of a main muffler 17 is joined to the other end of the exhaust pipe 16 by welding. .

  The outer diameter of the central portion of the main muffler 17 is formed larger than the outer diameter of the exhaust pipe 16, and an expansion chamber 17a (see FIG. 2) is formed inside the main muffler 17. Therefore, the exhaust gas introduced into the main muffler 17 from the exhaust pipe 16 is expanded, resonated, interfered with, etc. in the expansion chamber 17a of the main muffler 17, so that the exhaust sound of the engine 12 is silenced.

One end of an exhaust pipe 18 constituting a rear pipe is joined to the other end of the main muffler 17 by welding, and one end of a sub muffler 19 is joined to the other end of the exhaust pipe 18 by welding. Yes.
The outer diameter of the central portion of the sub muffler 19 is formed larger than the outer diameter of the exhaust pipe 18, and an expansion chamber is formed inside the sub muffler 19. Therefore, the exhaust gas introduced from the exhaust pipe 18 into the sub muffler 19 is expanded, resonated, interfered with, etc. in the expansion chamber of the sub muffler 19, so that the exhaust sound of the engine 12 is further silenced.

  In FIG. 2, one end 17 b of the main muffler 17 is tapered, and the outer peripheral portion of the other end 16 a of the exhaust pipe 16 is joined to the inner peripheral surface of the one end 17 b of the main muffler 17. One end portion 17b of the exhaust pipe 17 and the other end portion 16a of the exhaust pipe 16 are joined by a welded portion 25a.

  The other end portion 17 c of the main muffler 17 is tapered, and the outer peripheral portion of the one end portion 18 a of the exhaust pipe 18 is inserted into the inner peripheral surface of the other end portion 17 c of the main muffler 17. The other end portion 17c of the exhaust pipe 18 and the one end portion 18a of the exhaust pipe 18 are joined by a welded portion 25b.

  For this reason, the outer diameters of the exhaust pipes 16 and 18 are smaller than the outer diameters of the one end portion 17 b and the other end portion 17 c of the main muffler 17.

  One end of the tail pipe 20 is joined to the other end of the sub-muffler 19 by welding, and the other end of the tail pipe 20 communicates with the outside air. Therefore, the exhaust gas exhausted from the engine 12 to the exhaust manifold 13 is exhausted to the outside through the exhaust pipe 14, the catalytic converter 15, the exhaust pipe 16, the main muffler 17, the exhaust pipe 18, the sub muffler 19, and the tail pipe 20. .

  In the present embodiment, the exhaust manifold 13, the exhaust pipe 14, the catalytic converter 15, the exhaust pipe 16, the main muffler 17, the exhaust pipe 18, the sub muffler 19 and the tail pipe 20 constitute a hollow exhaust system component. These exhaust system components constitute the exhaust device 11 of the engine 12.

  Further, the catalytic converter 15 has a hollow outer cylinder containing the Yamamoto catalyst. Further, the exhaust pipes 14, 16 and 18 constitute one exhaust system part, and the catalytic converter 15, the main muffler 17 and the sub muffler 19 constitute other exhaust system parts.

  On the other hand, a part of the extending direction of the exhaust pipes 14, 16, 18 has PCCP shells (Pseudo-Cylindrical Converged Polyshells) 21 to 23 as a polyhedral structure.

  The PCCP shells 21 to 23 are so-called pseudo-cylindrical concave polyhedrons. As shown in FIG. 3, the surfaces of the adjacent polygons 24 share one side, and one side between the surfaces of the polygon 24 is It has a polyhedral structure that is connected in a concavo-convex shape so as to form a mountain ridge line 24a (shown by a solid line) or a valley 24b (shown by a broken line).

  Here, the cross-sectional second moment (bending rigidity) of the PCCP shells 21 to 23 is reduced by adjusting the depths of the crests 24c and the valleys 24b formed by one side of the surface of the polygon 24. Can be considered.

また、図５（ａ）に示すように、延在方向に外径が同一である一般的な中空のパイプ２６の矢視Ｂ−Ｂ方向に切断したときの中空のパイプ２６の断面を図５（ｂ）で示したときに、中空のパイプ２６の平板２６ａの軸方向長さをλ、平板２６ａの板厚をｔとしたときに、中空のパイプ２６の断面二次モーメントは、式の（２）で表される。

上記の（１）に基づいて求められるＰＣＣＰシェル２１〜２３の断面二次モーメントを、上記の（２）で求められる中空状のパイプ３６の断面二次モーメントよりも小さくするには、以下のようにすることが考えられる。

上記の式（３）にα＝λｓｉｎθを代入すると、ＰＣＣＰシェル２１〜２３の山の頂部２４ｃから谷２４ｂまでの深さをα＜√２ｔに設定すると、中空のパイプ２６に比べてＰＣＣＰシェル２１〜２３の断面二次モーメントを小さくする、すなわち、ＰＣＣＰシェル２１〜２３の曲げ剛性を小さくすることができるものと考えられる。 Specifically, as shown in FIG. 4A, when the cross sections of the PCCP shells 21 to 23 when the PCCP shells 21 to 23 are cut in the direction of arrow AA are shown in FIG. When the depth of the crest 24c and the valley 24b of the polygon 24 is α, the length of the ridge 24a of the mountain is λ, the thickness of the polyhedral structure is t, and the inclination angle of the ridge λ of the mountain is θ. The average value of the sectional moment of inertia of the PCCP shells 21 to 23 is generally expressed by the following (1).

Further, as shown in FIG. 5 (a), a cross-section of the hollow pipe 26 when the general hollow pipe 26 having the same outer diameter in the extending direction is cut in the direction of arrow BB is shown in FIG. When (b) indicates that the axial length of the flat plate 26a of the hollow pipe 26 is λ and the thickness of the flat plate 26a is t, the sectional moment of inertia of the hollow pipe 26 is expressed by the equation ( 2).

In order to make the cross-sectional secondary moment of the PCCP shells 21 to 23 obtained based on the above (1) smaller than the cross-sectional secondary moment of the hollow pipe 36 obtained in the above (2), it is as follows. Can be considered.

When α = λsinθ is substituted into the above equation (3), the depth from the crest 24c to the valley 24b of the PCCP shells 21 to 23 is set to α <√2t, compared to the hollow pipe 26, the PCCP shell 21 It is considered that the second-order moment of -23 can be reduced, that is, the bending rigidity of the PCCP shells 21-23 can be reduced.

Further, hollow support brackets 32 and 33 are joined to the catalytic converter 15 by welding, and the support brackets 32 and 33 are provided upstream and downstream in the exhaust gas exhaust direction with respect to the catalytic converter 15. Is provided.
In the present embodiment, upstream means upstream in the exhaust direction (circulation direction) of exhaust gas, and downstream means downstream in the exhaust direction of exhaust gas.

  Further, hollow support brackets 34 and 35 are joined to the main muffler 17 by welding, and the support brackets 34 and 35 are provided on the upstream side and the downstream side in the exhaust direction of the exhaust gas with respect to the main muffler 17. It has been.

  As shown in FIG. 6, the support brackets 32 to 35 are attached to a vehicle body 38 such as a side member or a cross member via support rubbers 36 and 41, respectively.

  In FIG. 6, the positional relationship between the main muffler 17 and the vehicle body 38 will be described. The catalytic converter 15 is also attached to the vehicle body 38 with the same structure as the main muffler 17 and will not be described.

  In FIG. 6, one end portions of the support brackets 34 and 35 are joined to the main muffler 17 by welded portions 39 and 40, and the other end portions of the support brackets 34 and 35 are inserted through holes 36a of the support rubbers 36 and 41, 41a is inserted through each.

  In addition, one end portions of the support brackets 42 and 43 are inserted into the insertion holes 36b and 41b of the support rubbers 36 and 41, respectively, and the other end portions of the support brackets 42 and 43 are connected to the vehicle body 38 by the welded portions 44 and 45, respectively. Are joined to each other. Note that the support brackets 34, 35, 42, and 43 may be integrated with the main muffler 17 and the vehicle body 38.

  Therefore, the main muffler 17 is elastically attached to the vehicle body 38 via the support brackets 34 and 35, the support rubbers 36 and 41, and the support brackets 42 and 43, so that the vehicle body 38 and the main muffler 17 are supported by the support rubbers 36 and 41. The vibration is suppressed from being transmitted between the two.

  Further, the catalytic converter 15 is also elastically attached to the vehicle body 38 via the support brackets 32 and 33, a support rubber (not shown) and a support bracket on the vehicle body 38 side, so that the support rubber is used between the vehicle body 38 and the catalytic converter 15. Transmission of vibration is suppressed. In this way, by attaching the exhaust device 11 to the vehicle body 38, vibrations are suppressed from being transmitted between the vehicle body 38 and the exhaust device 11.

Next, the operation will be described.
When external vibration is input from the engine 12 or the vehicle body 38 to the exhaust device 11, the external vibration is concentrated on the welded portion where the outer diameter changes greatly. In FIG. 2, focusing on the welded part (joined part) 31 a of the other end 17 c of the main muffler 17 and the one end 18 a of the exhaust pipe 18, one end of the exhaust pipe 18 is formed on the inner peripheral surface of the other end 17 c of the main muffler 17. Since the outer peripheral portion of the portion 18a is inserted and the other end portion 17c of the main muffler 17 and the one end portion 18a of the exhaust pipe 18 are joined by the welded portion 25b, the cross-sectional area of the welded portion 31a is the same as that of the main muffler 17. It becomes the same as the outer diameter of the other end portion 17c and becomes larger than the outer diameter of the one end portion 18a of the exhaust pipe 18, and the stress is easily concentrated on the welded portion 31a. The same applies to the welding part (joining part) 31b between the one end 17b of the main muffler 17 and the other end 16a of the exhaust pipe 16.

  In the present embodiment, the exhaust pipe 18 has a PCCP shell 23 in a part of the extending direction of the exhaust pipe 18, and the polygonal surface 24 of the polygon 24 is shared by the faces of the polygon 24. One side of each of these surfaces is connected in a concavo-convex shape so as to form a ridge line 24a or a valley 24b of a mountain.

  Therefore, by setting the depth from the crest 24c to the valley 24b of the PCCP shell 23 to α <√2t, the polygon 24 is formed so that the bending rigidity of the PCCP shell 23 is lowered, thereby extending the length. Compared to a hollow pipe 26 having a uniform outer diameter in the direction of the direction, the secondary moment of section of the PCCP shell 23 can be reduced, and the bending rigidity of the PCCP shell 23 can be reduced.

  For this reason, when external vibration is input to the exhaust device 11, the stress input to the exhaust pipe 16, the main muffler 17, and the exhaust pipe 18 by the external vibration is applied to the PCCP shell 22 of the exhaust pipe 16 and the PCCP shell 23 of the exhaust pipe 18. And can be dispersed. As a result, it is possible to alleviate stress concentration on the welded part 31b between the exhaust pipe 16 and the main muffler 17 and the welded part 31a between the main muffler 17 and the exhaust pipe 18, and the durability of the welded parts 31a and 31b. Can be improved.

  In the present embodiment, since exhaust pipe 14 has PCCP shell 21 in a part in the extending direction of exhaust pipe 14, stress is applied to the welded portion of the other end of exhaust pipe 14 and one end of catalytic converter 15. Can be mitigated, and the durability of the welded portion can be improved.

  Thus, in this Embodiment, durability of the welding parts 31a and 31b etc. can be improved by comprising a part of extension direction of the exhaust pipes 14, 16, and 18 from the PCCP shells 21-23. Therefore, a flexible tube, a sleeve member, etc. can be made unnecessary as in the prior art, and an increase in the weight of the exhaust device 11 can be prevented, and an increase in manufacturing cost of the exhaust device 11 can be prevented. .

  In the present embodiment, the exhaust pipes 14, 16, and 18 are partially configured from the PCCP shells 21 to 23, so that vibration characteristics transmitted from the engine 12 to the exhaust device 11 and the vehicle body 38 can be reduced. Since the vibration characteristic of the elastic vibration of the exhaust device 11 can be adjusted with respect to the vibration characteristic transmitted to the exhaust device 11, the exhaust device 11 and the engine 12 resonate, or the exhaust device 11 and the vehicle body 38 Resonance can be prevented.

  Further, in the present embodiment, as shown in FIG. 1, since the exhaust pipe 18 has a bent portion 18b, input vibrations from the engine 12 and the vehicle body 38 may be concentrated on the bent portion 18b. Conceivable.

  However, in the present embodiment, the stress input to the bent portion 18b due to external vibration can be dispersed in the PCCP shell 23 of the exhaust pipe 18, so that the stress concentration on the bent portion 18b can be reduced. The durability of the exhaust pipe 18 can be improved.

  Further, in order to avoid interference between the exhaust device 11 and peripheral members when external vibration is input to the exhaust device 11, for example, an arbitrary portion of the exhaust pipe 18 is crushed to change the outer diameter shape of the exhaust pipe 18. In this way, a gap may be secured between the exhaust pipe 18 and the peripheral member.

  In this case, it is conceivable that the input vibration is concentrated on the crushed portion. However, since the stress input to the crushed portion by the external vibration can be dispersed in the PCCP shell 23 of the exhaust pipe 18, It is possible to alleviate the concentration of stress on the part, and the durability of the exhaust pipe 18 can be improved.

  In the present embodiment, cylindrical PCCP shells 21 to 23 are provided as part of the extending direction of the exhaust pipes 14, 16, and 18 as a multi-sided structure. It is not necessary to be a thing, and a rectangular tube shape may be sufficient.

  Further, the exhaust pipes 14, 16, and 18 may be composed of PCCP shells 21 to 23. That is, you may comprise the outer peripheral part of the exhaust pipes 14, 16, and 18 from the PCCP shells 21-23 over the extending direction.

  Moreover, in this Embodiment, although some exhaust pipes 14, 16, and 18 are comprised from the PCCP shells 21-23, any one or more parts of the exhaust pipes 14, 16, and 18 are comprised. You may comprise from a PCCP shell.

(Second Embodiment)
FIGS. 7 to 9 are views showing a second embodiment of the exhaust system for an internal combustion engine according to the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and described. Omitted.

  In the present embodiment, a part of the support brackets 32 to 35 and the support brackets 42 and 43 in the extending direction is constituted by a PCCP shell.

In FIG. 7, the support brackets 35 and 43 provided with PCCP shells 46 and 47 are shown. In this embodiment, PCCP shells are also provided in the support brackets 32 to 34 and 42 shown in FIG.
The configurations of the PCCP shells 46 and 47 are the same as those of the PCCP shells 21 to 23 of the first embodiment.
In the present embodiment, the support brackets 32 to 35 constitute one exhaust system part, and the catalytic converter 15 and the main muffler 17 constitute another exhaust system part.

  That is, the support bracket 43 of the present embodiment constitutes an exhaust system component, and one end portion is joined to the main muffler 17 by the welded portion 40 and the other end portion is a support rubber 41 that is a support member. The support bracket 43 and the vehicle body 38 are supported.

  Here, when the main muffler 17 is joined to the support bracket 35 by the welded portion 40, stress is likely to concentrate on the welded part (joined part) 48 of the small-diameter support bracket 35 and the large-diameter main muffler 17.

  In the present embodiment, the support brackets 35 and 43 have PCCP shells 46 and 47 in a part of the extending direction of the support brackets 35 and 43. As shown in FIG. The surfaces of the polygons 24 share one side, and the sides of the polygons 24 are connected in an uneven shape so as to form a ridge line 24a or a valley 24b.

  For this reason, the polygon 24 is formed so that the bending rigidity of the PCCP shells 46 and 47 is lowered by setting the depth from the crest 24c to the valley 24b of the PCCP shells 46 and 47 to α <√2t. As a result, compared to the hollow pipe 26 having a uniform outer diameter in the extending direction, the cross-sectional secondary moment of the PCCP shells 46 and 47 can be reduced, and the bending rigidity of the PCCP shells 46 and 47 is lowered. be able to.

  For this reason, even when external vibration is input from the vehicle body 38 to the main muffler 17, the stress input to the main muffler 17 due to the external vibration can be distributed to the PCCP shells 46 and 47 of the support brackets 35 and 43. .

  As a result, it is possible to alleviate stress concentration on the welded part 48 of the main muffler 17 and the support bracket 35 and the welded part (joined part) 49 of the support bracket 47 and the vehicle body 38, and the durability of the welded parts 48 and 49 is improved. Can be improved.

  Also, by providing the PCCP shell 46 on the support brackets 32 to 35, the coupling rigidity of the support brackets 32 to 35 (the degree of behavior following the catalytic converter 15 and the main muffler 17 with respect to the vehicle body 38 when the vehicle body 38 behaves) is adjusted. be able to.

  In the present embodiment, if a part of the extending direction of the support bracket 35 is composed of the PCCP shell 46, it is possible to alleviate stress concentration on the welded portion 48 between the main muffler 17 and the support bracket 35. Therefore, it is not necessary to provide the PCCP shell 47 in the support bracket 43. The same applies to the support brackets 32 to 34.

  Further, if the PCCP shell 46 is provided in the support brackets 32 to 35, stress concentration on the welded portions 31a and 31b between the main muffler 17 and the exhaust pipes 16 and 18 can be reduced. , 16 and 18 can be made unnecessary to provide the PCCP shells 21 to 23.

  In the present embodiment, the support brackets 32 to 35, 42, and 43 are partially formed from the PCCP shells 46 and 47. However, the support brackets 32 to 35, 42, and 43 are formed from the PCCP shell 46. , 47. That is, you may comprise the outer peripheral part of the support brackets 32-35, 42, 43 from the PCCP shell 46 over the extending direction.

  Further, depending on the layout of the exhaust device 11 and the magnitude of vibration, the exhaust pipe 14 is connected to a transmission case 51 as a support member connected to the engine 12 via a support bracket 52 as shown in FIG. It may be.

  In FIG. 8, one end of a hollow support bracket 52 as an exhaust system component is joined to the exhaust pipe 14 by a welded portion 53, and the other end of the support bracket 52 is joined to the transmission case 51 by a welded portion 54. It is joined to. The outer diameter of the support bracket 52 is smaller than the outer diameter of the exhaust pipe 14.

  As shown in FIG. 9, the support bracket 52 has a PCCP shell 55 in a part in the extending direction of the support bracket 52, and the PCCP shell 55 is the PCCP shells 21 to 23 of the first embodiment. It has the same configuration. In the present embodiment, the support bracket 52 constitutes one exhaust system part, and the exhaust pipe 14 constitutes another exhaust system part.

  In the present embodiment, a part of the extending direction of the support bracket 52 has a PCCP shell 55, and the PCCP shell 55 has one side shared by the faces of the polygon 24, and one side of the faces of the polygon 24. Are formed in such a manner that they are connected in a concavo-convex shape so as to form a ridge line 24a or a valley 24b.

  For this reason, by setting the depth from the crest 24c to the valley 24b of the PCCP shell 55 to α <√2t, the polygon 24 is formed so that the bending rigidity of the PCCP shell 55 is lowered. Compared to the hollow pipe 26 having a uniform outer diameter in the present direction, the cross-sectional secondary moment of the PCCP shell 55 can be reduced, and the bending rigidity of the PCCP shell 55 can be reduced.

  Therefore, when external vibration is input from the transmission case 51 to the exhaust pipe 14, the stress input to the exhaust pipe 14 by the external vibration can be dispersed in the PCCP shell 55 of the support bracket 52.

  As a result, it is possible to alleviate stress concentration on the welded part (joined part) 56 between the exhaust pipe 14 and the support bracket 52 and the welded part 57 between the transmission case 51 and the support bracket 52, and the welded part 56, The durability of 57 can be improved.

  Further, by providing the support bracket 52 with the PCCP shell 55, the coupling rigidity of the support bracket 52 can be adjusted.

  In the present embodiment, a part of the extending direction of the support bracket 52 is constituted by the PCCP shell 55, but the support bracket 52 may be constituted by the PCCP shell 55. That is, you may comprise the outer peripheral part of the support bracket 52 from the PCCP shell 55 over the extending direction.

(Third embodiment)
FIGS. 10 and 11 are views showing a third embodiment of the exhaust system for an internal combustion engine according to the present invention. The same components as those in the first embodiment are denoted by the same reference numerals and described. Omitted.

10 and 11, the main muffler 17 has a PCCP shell 61 in a part of the extending direction of the main muffler 17, and the PCCP shell 61 is the PCCP shells 21 to 23 of the first embodiment. It has the same configuration.
However, since the outer diameter of the main muffler 17 is larger than the outer diameter of the exhaust pipes 14, 16, 18, the polygon 24 of the PCCP shell 61 is larger than the polygon 24 of the PCCP shells 21 to 23. The number is increasing or the area is increasing.

Further, the catalytic converter 15 and the sub muffler 19 have a PCCP shell 61 in a part of the extending direction of the catalytic converter 15 and the sub muffler 19, respectively. Since the function of the PCCP shell 61 is the same as that of the PCCP shell 61 of the main muffler 17, the main muffler 17 will be described with reference to FIG.
In the present embodiment, the catalytic converter 15, the main muffler 17 and the sub muffler 19 constitute one exhaust system component, and the exhaust pipes 14, 16, and 18 constitute other exhaust system components.

  In the present embodiment, the main muffler 17 has a PCCP shell 61 in a part of the extending direction of the main muffler 17, and the PCCP shell 61 shares one side of the polygon 24, and the polygon 24 One side of each of the surfaces is configured to be connected in a concavo-convex shape so as to form a ridge line 24a or a valley 24b of a mountain.

  Therefore, by setting the depth from the crest 24c to the valley 24b of the PCCP shell 61 to α <√2t, by forming the shape of the polygon 24 so that the bending rigidity of the PCCP shell 61 is reduced. Compared with the hollow pipe 26 having a uniform outer diameter in the extending direction, the sectional moment of inertia of the PCCP shell 61 can be reduced, and the bending rigidity of the PCCP shell 61 can be reduced.

  For this reason, when external vibration is input to the exhaust device 11, the stress input to the exhaust pipe 16, the main muffler 17, and the exhaust pipe 18 due to the external vibration can be dispersed in the PCCP shell 61 of the main muffler 17.

  As a result, it is possible to alleviate stress concentration on the welded part 31b between the exhaust pipe 16 and the main muffler 17 and the welded part 31a between the main muffler 17 and the exhaust pipe 18, and the durability of the welded parts 31a and 31b can be reduced. Can be improved.

  In addition, since a part of the extending direction of the catalytic converter 15 and the sub-muffler 19 is constituted by the PCCP shell 61, the welded part between the other end of the exhaust pipe 14 and one end of the catalytic converter 15 and the other end of the exhaust pipe 18. It is possible to alleviate the concentration of stress on the welded portion of the sub-muffler 19 and one end of the sub-muffler 19 and improve the durability of the welded portion.

As described above, in the present embodiment, by configuring part of the extending direction of the catalytic converter 15, the main muffler 17 and the sub muffler 19 from the PCCP shell 61, it is possible to improve the durability of the welded portions 31a, 31b and the like. it can.
For this reason, a flexible tube, a sleeve member, etc. can be made unnecessary conventionally, and it can prevent that the weight of the exhaust apparatus 11 increases, and can prevent that the manufacturing cost of the exhaust apparatus 11 increases. it can.

  In the present embodiment, a part of the catalytic converter 15, the main muffler 17 and the sub muffler 19 in the extending direction is constituted by the PCCP shell 61, so that vibration characteristics transmitted from the engine 12 to the exhaust device 11 and the vehicle body 38 can be obtained. Since the vibration characteristic of the elastic vibration of the exhaust device 11 can be adjusted with respect to the vibration characteristic transmitted from the exhaust device 11 to the exhaust device 11, it is possible to prevent the exhaust device 11 from resonating with the engine 12 or the vehicle body 38. Can do.

  In the present embodiment, a cylindrical PCCP shell 61 is provided as a polyhedral structure in a part of the extending direction of the catalytic converter 15, the main muffler 17 and the sub muffler 19. However, as the polyhedral structure, a cylindrical PCCP shell 61 is provided. It is not necessary to have a rectangular shape, and may be a rectangular tube as long as it has a polyhedral structure.

  In the present embodiment, the catalytic converter 15, the main muffler 17, and the sub muffler 19 may be configured from the PCCP shell 61. That is, the PCCP shell 61 may be provided along the extending direction of the catalytic converter 15, the main muffler 17, and the sub muffler 19.

Further, in the present embodiment, a part of the catalytic converter 15, the main muffler 17 and the sub muffler 19 is constituted by the PCCP shell 61, but at least one of the catalytic converter 15, the main muffler 17 and the sub muffler 19 is included. A part may be composed of a PCCP shell.
In each of the above embodiments, the exhaust system parts are joined by welding, but the joined parts may be joined by a method other than welding.

  The embodiment disclosed this time is illustrative in all respects and is not limited to this embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of the claims, and is intended to include all modifications within the meaning and scope equivalent to the scope of the claims.

  As described above, the internal combustion engine exhaust system according to the present invention prevents an increase in the weight of the exhaust system and an increase in the manufacturing cost of the exhaust system, and external vibration is input to the exhaust system components. In this case, it is possible to alleviate the stress concentration at the joint part of the exhaust system parts, and to improve the durability of the joint part. It is provided on the downstream side, and is useful as an exhaust device or the like in which the end of one hollow exhaust system component is joined to another hollow exhaust system component.

11 Exhaust system 12 Engine (Internal combustion engine)
13 Exhaust manifold (exhaust system parts)
14 Exhaust pipe (other exhaust system parts)
16, 18 Exhaust pipe (one exhaust pipe part, other exhaust system parts)
15 Catalytic converter (one exhaust system component, another exhaust system component)
16a other end 17 main muffler (one exhaust system part, another exhaust system part)
17b, 18a One end 17c Other end 19 Sub-muffler (One exhaust system component, another exhaust system component)
20 Tail pipe (exhaust system parts)
21-23 PCCP shell (polyhedral structure)
24 Polygon 24a Mountain ridge line 24b Valley 24c Mountain top 25a, 25b, 39, 40 Welded portion 31a, 31b Welded part (joined part)
32-35 Support bracket (one exhaust system part)
36, 41 Support rubber (support member)
38 Car body (support member)
42, 43 Support bracket (support member)
46, 47 PCCP shell 48, 49 Welding part (joining part)
51 Transmission case (support member)
52 Support bracket (one exhaust system part)
53 Welding part 55 PCCP shell 56 Welding part (joining part)
61 PCCP shell

Claims (5)

In the exhaust system provided on the downstream side of the exhaust direction of the exhaust gas with respect to the internal combustion engine, the end of one hollow exhaust system component is joined to another hollow exhaust system component,
The one exhaust system component has a polyhedral structure along the circumferential direction in at least a part of the extending direction of the one exhaust system component,
The polyhedral structure is characterized in that adjacent polygonal surfaces share one side, and one side of the polygonal surfaces is connected in a concavo-convex shape so as to form a ridge line or valley of a mountain. Engine exhaust system. In the polyhedral structure, α <√2 · t, where α is the depth from the top of the mountain formed by one side of the polygonal surface to the valley, and t is the plate thickness of the polyhedral structure. The exhaust system for an internal combustion engine according to claim 1. The other exhaust system component is configured by a muffler or a catalytic converter, and the one exhaust system component is configured by an exhaust pipe to which an end of the muffler or the catalytic converter is joined. An exhaust system for an internal combustion engine according to claim 1 or 2. 2. The other exhaust system component is configured by an exhaust pipe, and the other exhaust system component is configured by a muffler or a catalytic converter to which an end of the exhaust pipe is joined. Item 3. An exhaust system for an internal combustion engine according to Item 2. The other exhaust system component includes at least one of an exhaust pipe, a catalytic converter, and a muffler, and the one exhaust system component has at least one or more of the exhaust pipe, the catalytic converter, and the muffler at one end. The exhaust device for an internal combustion engine according to claim 1, wherein the exhaust device is composed of at least one support bracket that is joined to the support member and has the other end supported by the support member.

Images