JP6154421B2 - Exhaust pipe structure - Google Patents

Description

  The present invention relates to an exhaust pipe structure constituting an exhaust system of an internal combustion engine.

  2. Description of the Related Art Conventionally, a configuration is known in which an exhaust system is made compact by connecting a plurality of exhaust pipes extending in different directions.

  FIG. 4 of Patent Document 1 shows a first exhaust pipe (referred to as a first casing in Patent Document 1) extending along the first direction, and a downstream of the exhaust gas flow direction from the first exhaust pipe. A second exhaust pipe (referred to as a second casing in Patent Document 1) located on the side and extending along a second direction orthogonal to the first direction is connected to a connecting member (in Patent Document 1). The connection structure is disclosed in the following. In addition, a DPF (Diesel Particle Filter) and a selective catalytic reduction catalyst are disposed inside these exhaust pipes.

JP 2013-185529 A

  By the way, as schematically shown in FIG. 9, the exhaust system is further reduced in size by inserting the upstream end portion of the second exhaust pipe 200 into the downstream end portion of the first exhaust pipe 100 (first A configuration in which these exhaust pipes are connected to each other is conceivable so that the first exhaust pipe 100 and the second exhaust pipe 200 overlap each other when viewed from the direction in which the exhaust pipe 100 extends. In other words, the exhaust system can be made more compact by this insertion dimension (dimension t in FIG. 9) (for example, when the left-right direction in FIG. 9 is the vehicle width direction, the vehicle width direction of the exhaust system) It is possible to shorten the dimensions of 9, an NSR (NOx Storage Reduction) catalyst 101 is disposed in the first exhaust pipe 100, and a DPF 201 is disposed in the second exhaust pipe 200, respectively.

  However, in this case, the exhaust gas distribution area (exhaust gas distribution area in the portion s in FIG. 9) in the connection portion between the first exhaust pipe 100 and the second exhaust pipe 200 is reduced by the insertion dimension. become. For this reason, if the exhaust pipes are simply connected to each other so that the upstream end portion of the second exhaust pipe 200 is inserted into the downstream end portion of the first exhaust pipe 100, the exhaust gas at the connecting portion is not affected. There is a possibility that the discharge performance deteriorates and the pressure in the exhaust pipe increases.

  The present invention has been made in view of such a point, and an object of the present invention is to connect the exhaust pipes to each other with respect to the configuration of the exhaust pipes that connect a plurality of exhaust pipes extending in different directions. It is in providing the structure which can suppress the pressure rise of exhaust gas.

  In order to achieve the above-mentioned object, the solution means of the present invention includes a first exhaust pipe extending along a first direction, the downstream of the first exhaust pipe in the exhaust gas flow direction, and the first exhaust pipe. The second exhaust pipe extending along a second direction intersecting the direction of the first exhaust pipe, the first exhaust pipe and the second exhaust pipe so that they overlap each other when viewed from the first direction. And a connecting member for connecting the two. An opening for communicating the inside of the first exhaust pipe and the inside of the second exhaust pipe to the connecting member; the opening adjacent to the opening as viewed from the first direction; And a bottom plate portion formed to correspond to a region where the second exhaust pipe overlaps when viewed from the first direction. And the groove | channel extended toward the said opening along the outer edge part of this bottom plate part is formed in the surface which faces the inner side of said 1st exhaust pipe in the said bottom plate part.

  Due to this specific matter, a part of the exhaust gas flowing into the connecting member from the first exhaust pipe flows along a groove formed in the bottom plate portion of the connecting member, and the inside of the second exhaust pipe through the opening through the groove. Will flow into. In other words, the flow of exhaust gas is guided by this groove, so that even if the first exhaust pipe and the second exhaust pipe are connected so as to overlap each other, the exhaust gas exhaust performance at this connecting portion is ensured satisfactorily. Thus, it is possible to suppress the pressure of the exhaust gas from increasing at this connecting portion.

  In addition, the first exhaust purification device is disposed inside the first exhaust pipe, while the second exhaust in a region where the first exhaust pipe and the second exhaust pipe overlap when viewed from the first direction. It is preferable to position the second exhaust purification device inside the pipe.

  Accordingly, the inside of the second exhaust pipe in the region where the first exhaust pipe and the second exhaust pipe overlap as viewed from the first direction can be effectively used as an arrangement space for the second exhaust purification device, and a plurality of exhaust pipes can be used. The exhaust gas purification performance can be improved by arranging the purification device.

  It is preferable that the connecting member is molded by lost wax casting of stainless steel.

  According to this, while being able to raise the freedom degree of the shape of a connection member, improvement of corrosion resistance can be aimed at.

  In the present invention, the first exhaust pipe and the second exhaust pipe having different extending directions are connected by the connecting member so that they overlap each other, and a groove for guiding the flow of the exhaust gas is formed in the bottom plate portion of the connecting member. . As a result, the exhaust gas pressure can be prevented from increasing at the connecting portion while the exhaust system is made compact.

It is the figure which looked at the exhaust system containing a manipulator and its periphery from the back of a vehicle. It is the II arrow directional view in FIG. FIG. 3 is a view taken along arrow III in FIG. 1. It is a front view which shows a connection member. It is a top view which shows a connection member. It is a figure for demonstrating the area | region where a 1st exhaust pipe and a 2nd exhaust pipe overlap. It is sectional drawing along the VII-VII line in FIG. It is sectional drawing which shows the exhaust pipe connection part by a connection member. It is sectional drawing which shows the outline of the structure which inserted the upstream end part of the 2nd exhaust pipe in the downstream end part of the 1st exhaust pipe.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. This embodiment demonstrates the case where this invention is applied to the exhaust system of the diesel engine (internal combustion engine) mounted in the vehicle.

-Outline configuration of exhaust system-
FIG. 1 is a view of a part of an exhaust system including a manipulator and its periphery as seen from the rear of the vehicle. FIG. 2 is a view taken in the direction of arrow II in FIG. 1 (viewed from above). 3 is a view taken in the direction of arrow III in FIG. 1 (viewed from the right side of the vehicle).

  As shown in these drawings, in the exhaust system, a manifold connection pipe 1, a first maniverter 2, a connecting member 3, and a second maniverter 4 are arranged in this order from the upstream side to the downstream side in the exhaust gas flow direction. .

(Manifold connection piping)
The manifold connection pipe 1 is made of stainless steel, and connects the exhaust manifold (not shown) and the first manifold 2. The manifold connecting pipe 1 has an upstream portion in the exhaust gas flow direction extending in a substantially horizontal direction (vehicle width direction), and a downstream portion in the exhaust gas flow direction in a substantially vertical direction (more specifically, predetermined with respect to the vertical direction). Are inclined so as to extend at an inclination angle (for example, a direction inclined by about 15 °).

  A flange 11 is provided at the upstream end of the manifold connection pipe 1 in the exhaust gas flow direction. This flange 11 is connected to an exhaust manifold (not shown). In the case of an engine equipped with a turbocharger, the flange 11 is connected to a turbine housing of a turbocharger (not shown).

(First maniverter)
The first maniverter 2 includes a substantially cylindrical first exhaust pipe 21 and an NSR catalyst (see a broken line in FIG. 1) 22 accommodated in the first exhaust pipe 21.

  The first exhaust pipe 21 is made of stainless steel, and extends along the direction in which the downstream portion of the manifold connection pipe 1 in the exhaust gas flow direction extends. The direction in which the first exhaust pipe 21 extends (the direction along the center line O1 (see FIG. 1) of the first exhaust pipe 21) corresponds to the first direction in the present invention.

  Further, the outer diameter of the upstream end of the first exhaust pipe 21 in the exhaust gas flow direction substantially matches the inner diameter of the downstream end of the manifold connection pipe 1 in the exhaust gas flow direction. The upstream end of the first exhaust pipe 21 in the exhaust gas flow direction is inserted into the downstream end of the manifold connection pipe 1 in the exhaust gas flow direction, and the manifold connection pipe 1 and the first exhaust pipe 21 Are joined by means such as welding. Note that a plurality of brackets (not shown) for fixing the first maniverter 2 to a vehicle body or the like are attached to a plurality of locations on the outer peripheral surface of the first exhaust pipe 21.

  The NSR catalyst 22 (the first exhaust purification device in the present invention) occludes NOx in the exhaust when the oxygen concentration of the exhaust gas flowing into the first maniverter 2 is high, and the exhaust gas flowing into the first maniverter 2 When the oxygen concentration is reduced and a reducing agent is present, the stored NOx is reduced. Thereby, HC, CO and NOx in the exhaust gas can be purified.

(Second maniverter)
The second manipulator 4 will be described before describing the connecting member 3 which is a feature of the present embodiment.

  The second manipulator 4 includes an exhaust pipe unit 41, and an NSR catalyst 42 and a DPF 43 (see the broken lines in FIG. 1 respectively) housed in the exhaust pipe unit 41.

  The exhaust pipe unit 41 includes a second exhaust pipe 44 made of stainless steel, a first side cover 45, and a second side cover 46.

  The second exhaust pipe 44 is a cylindrical pipe extending in a substantially horizontal direction (vehicle width direction). The direction in which the second exhaust pipe 44 extends (substantially horizontal direction) corresponds to the second direction in the present invention. That is, the second exhaust pipe 44 extends along a second direction that intersects the first direction.

  The outer diameter dimension of the second exhaust pipe 44 is set larger than the outer diameter dimension of the first exhaust pipe 21 of the first maniverter 2. Further, the NSR catalyst (second exhaust purification device in the present invention) 42 accommodated in the second exhaust pipe 44 is more exhaust gas than the DPF 43 similarly accommodated in the second exhaust pipe 44. Arranged upstream in the flow direction.

  The NSR catalyst 42 accommodated in the second exhaust pipe 44 is larger than the NSR catalyst 22 provided in the first maniverter 2. The function is the same as that of the NSR catalyst 22 provided in the first maniverter 2. Further, the DPF 43 is made of, for example, a porous ceramic structure, and collects PM (Particulate Matter) contained in the exhaust gas when the exhaust gas passes through the porous wall. ing.

  As a feature of the second exhaust pipe 44, the upstream end of the second exhaust pipe 44 in the exhaust gas flow direction overlaps the first exhaust pipe 21. That is, when viewed from the direction in which the first exhaust pipe 21 extends (when viewed from the first direction), the first exhaust pipe 21 and the upstream end of the second exhaust pipe 44 in the exhaust gas flow direction are overlapping. More specifically, the exhaust pipes 21 and 44 overlap each other so that the center line O1 of the first exhaust pipe 21 intersects the outer peripheral surface of the second exhaust pipe 44 (see from the first direction). overlapping). The NSR catalyst 42 is accommodated in the second exhaust pipe 44 at the upstream end in the exhaust gas flow direction. For this reason, the center line O <b> 1 of the first exhaust pipe 21 also intersects with the outer peripheral surface of the NSR catalyst 42. That is, a part of the NSR catalyst 42 is disposed inside the second exhaust pipe 44 in a region where the first exhaust pipe 21 and the second exhaust pipe 44 overlap when viewed from the first direction.

  A plurality of brackets (not shown) for fixing the second manipulator 4 to a vehicle body or the like are attached to a plurality of locations on the outer peripheral surface of the second exhaust pipe 44.

  The first side cover 45 is disposed between a connecting member 3 and a second exhaust pipe 44, which will be described later, and forms an exhaust gas circulation space between the connecting member 3 and the second exhaust pipe 44. Is. The joining structure of the first side cover 45, the connecting member 3, and the second exhaust pipe 44 will be described later.

  The second side cover 46 covers the opening of the downstream end portion of the second exhaust pipe 44 in the exhaust gas flow direction. The second side cover 46 is provided with an exhaust pipe connecting portion 46a (see FIGS. 2 and 3), and the downstream side exhaust pipe 5 is connected to the exhaust pipe connecting portion 46a. The downstream exhaust pipe 5 extends along the vehicle width direction (the right direction in FIG. 1) from the exhaust pipe connection portion 46a and then bends toward the rear of the vehicle.

(Connecting member)
Next, the connecting member 3 will be described.

  The connecting member 3 is made of stainless steel, and is a member that connects the first exhaust pipe 21 of the first maniverter 2 and the exhaust pipe unit 41 of the second maniverter 4. The connecting member 3 is formed by stainless lost wax casting.

  An example of this lost wax casting will be described. First, wax (wax) is poured into a mold, a wax model is prepared, a coating is applied to the model, and the mold is sufficiently dried to prepare a mold. By applying heat to the mold, the wax in the coating is melted and discharged to create a cavity, which is baked and hardened in a firing furnace to produce a mold. A cast product (the connecting member 3) is produced by injecting molten metal into the completed mold and cooling it.

  FIG. 4 is a front view showing the connecting member 3 (as viewed from the rear of the vehicle as in FIG. 1). FIG. 5 is a plan view showing the connecting member 3 (viewed from the first direction). FIG. 7 is a cross-sectional view taken along line VII-VII in FIG. FIG. 8 is a cross-sectional view showing an exhaust pipe connecting portion by the connecting member 3.

  As shown in these drawings, the connecting member 3 includes a first exhaust pipe joint portion 31, a vertical wall portion 32, and a bottom plate portion 33.

  The first exhaust pipe joint portion 31 is a substantially cylindrical portion having a relatively short height dimension, and the inner diameter dimension thereof is the outer diameter dimension of the downstream end portion of the first exhaust pipe 21 in the exhaust gas flow direction. It is almost coincident. The downstream end portion of the first exhaust pipe 21 in the exhaust gas flow direction is inserted into the first exhaust pipe joint portion 31, and the first exhaust pipe 21 and the connecting member 3 (first exhaust pipe joint portion) are inserted in this insertion portion. 31) are joined by means such as welding.

  The vertical wall portion 32 is continuous to the lower side of the first exhaust pipe joint portion 31, and is a front vertical wall portion 32a (see FIG. 5) positioned on the vehicle front side and a rear vertical wall positioned on the vehicle rear side. Part 32b (see FIGS. 1 and 5). Inner side surfaces of the front vertical wall portion 32a and the rear vertical wall portion 32b (inner surface facing the outer peripheral surface of the second exhaust pipe 44 in a state where the connecting member 3 and the second exhaust pipe 44 are joined; FIG. 7, the inner side surface of the front vertical wall portion 32 a is indicated by reference numeral 32 e) and has a shape along the outer peripheral surface of the second exhaust pipe 44. The inner side surfaces 32e of the front vertical wall portion 32a and the rear vertical wall portion 32b are overlapped with the outer peripheral surface of the second exhaust pipe 44, and the connecting member 3 (the respective vertical wall portions 32a, 32b of the connecting member 3) is overlapped with this overlapping portion. ) And the second exhaust pipe 44 are joined together by means such as welding.

  Moreover, as shown in FIG. 4, the vertical wall part 32 is not formed in the vehicle right side. In other words, the lower portion of the first exhaust pipe joint portion 31 located on the right side of the vehicle is opened to the right side of the vehicle from the lower end edge (lower end edge 31a in FIG. 4). That is, the portion below the lower end edge 31a is an opening 34 that opens toward the right side of the vehicle. The opening 34 is used as a space for allowing the exhaust gas flowing into the connecting member 3 to flow toward the second manipulator 4. That is, the opening 34 communicates the inside of the first exhaust pipe 21 and the inside of the second exhaust pipe 44.

  Further, the edge portions near the opening 34 in the front vertical wall portion 32a and the rear vertical wall portion 32b are joined portions 32c having substantially flat outer surfaces to which the first side cover 45 of the second maniverter 4 is joined. It is formed as 32d.

  As shown in FIG. 5, the bottom plate portion 33 is located in the inner space of the first exhaust pipe joint 31, and in the exhaust gas flow direction in the second exhaust pipe 44 (shown by an imaginary line in FIG. 5). It is comprised with the board | plate material of the shape in alignment with the outer peripheral surface of an upstream end part. Specifically, as shown in FIG. 5, the bottom plate portion 33 corresponds to a region adjacent to the opening 34 when viewed from the first direction and where the first exhaust pipe 21 and the second exhaust pipe 44 overlap. It is composed of a shaped plate. Therefore, the bottom plate portion 33 has a shape including an end edge 33 a facing the opening 34 and a substantially arc-shaped outer edge 33 b connected to the inner surface of the first exhaust pipe joint portion 31.

  Here, the “region where the first exhaust pipe 21 and the second exhaust pipe 44 overlap” is shown in FIG. 6 (the first exhaust pipe 21 and the second exhaust pipe 44 viewed from the first direction, and the connecting member 3 is a region indicated by a broken line in FIG. The bottom plate portion 33 has a shape substantially corresponding to the shape of this region.

  Further, as shown in FIGS. 1 and 8, and in the state where the second exhaust pipe 44 is joined with the second exhaust pipe 44 in FIG. 4 and FIG. The bottom plate portion 33 is overlapped on the upper surface of the second exhaust pipe 44, and the connecting member 3 and the second exhaust pipe 44 are joined also in this overlapping portion.

  Further, as shown in FIG. 8, the first side cover 45 is joined across the second exhaust pipe 44 and the connecting member 3. Specifically, the first side cover 45 covers the opening 34 of the connecting member 3 and the opening of the upstream end portion of the second exhaust pipe 44 in the exhaust gas flow direction. As for this 1st side cover 45, the outer edge part is the 1st exhaust pipe joint part 31 of the said connection member 3, each vertical wall part 32a, 32b (the said joint part 32c formed in these vertical wall parts 32a, 32b, 32d) and over the opening edge of the upstream end portion of the second exhaust pipe 44 in the exhaust gas flow direction, and this overlapped portion is joined by means such as welding. Thereby, the internal space of the connection member 3 and the internal space of the second exhaust pipe 44 are communicated with each other via a space formed between the opening 34 of the connection member 3 and the first side cover 45.

  As shown in FIGS. 5 and 7, the connecting member 3 is characterized in that the bottom plate portion 33 of the connecting member 3 has a groove extending toward the opening 34 along the outer edge portion (the outer edge 33 b) of the bottom plate portion 33. 35 is formed.

  Specifically, the outer edge portion of the bottom plate portion 33, that is, the region along the substantially arc-shaped outer edge 33 b connected to the inner surface of the first exhaust pipe joint portion 31 in the bottom plate portion 33 is lower than the other regions. A recessed portion is formed on the side, and the recessed portion is formed as a groove 35. That is, the cross-sectional shape of the groove 35 at the cross-sectional position shown in FIG. 7 extends to the opening 34 along the upper surface of the bottom plate portion 33 (the surface facing the inner side of the first exhaust pipe 21) (see FIG. 5). reference).

  As described above, since the groove 35 is formed in the bottom plate portion 33, a part of the exhaust gas flowing into the connecting member 3 from the first exhaust pipe 21 of the first manipulator 2 flows along the groove 35. (The flow is guided by the groove 35), and flows from the open end (portion facing the opening 34) of the groove 35 into the second manipulator 4 through the opening 34.

  As described above, the exhaust pipe structure according to the present invention is formed.

(Exhaust gas flow)
Next, the flow of exhaust gas during engine operation will be described.

  The exhaust gas discharged from the engine flows into the first maniverter 2 through the exhaust manifold and the manifold connection pipe 1. The exhaust gas flowing into the first manipulator 2 is purified by the NSR catalyst 22 and then flows into the connecting member 3.

  Of the exhaust gas flowing into the connecting member 3, the exhaust gas flowing relatively to the right of the vehicle inside the connecting member 3 is along the center line O1 of the first exhaust pipe 21 (along the first direction). ) The inside of the connecting member 3 flows toward the opening 34. Therefore, the exhaust gas passes through the opening 34 as it is and flows toward the second manipulator 4 as indicated by an arrow A in FIGS. 7 and 8. That is, after flowing downward in the connecting member 3, the flow passes through the opening 34, and the flow direction is changed to the horizontal direction (the vehicle left side direction) along the inner surface shape of the first side cover 45. And a flow toward the DPF 43.

  On the other hand, of the exhaust gas flowing into the connecting member 3, a part of the exhaust gas flowing toward the bottom plate portion 33 is part of the groove 35 along the bottom plate portion 33 as indicated by an arrow B in FIGS. 5 and 8. Will flow into. As described above, the groove 35 extends along the outer edge portion of the bottom plate portion 33. That is, the groove 35 has an arc shape toward the opening 34. Therefore, the exhaust gas flowing along the groove 35 flows in an arc shape centering on the center line of the first exhaust pipe joint portion 31 of the connecting member 3 as shown by arrows C and D in FIG. It becomes. Then, the exhaust gas flows into the opening 34 from the open end (portion facing the opening 34) of the groove 35 to form an arc-shaped flow (as shown in FIG. 5, the arc-shaped when viewed from the first direction). And flow into the second manipulator 4.

  Specifically, the exhaust gas that has flowed through the front portion of the vehicle (upper portion in FIG. 5) of the groove 35 is the open end (opening 34) of the groove 35 as shown by an arrow E in FIGS. 5 flows into the inside of the second exhaust pipe 44 through the opening 34 and along the inner surface on the rear side of the second exhaust pipe 44 (the inner surface located on the rear side of the vehicle) (arrow E in FIG. 5). Among them, as shown by the broken line portion and the arrow E in FIGS. 7 and 8, it goes around the bottom plate portion 33 and flows into the second exhaust pipe 44). On the other hand, the exhaust gas that has flown through the rear portion of the vehicle (the lower portion in FIG. 5) of the groove 35 opens from the open end (portion facing the opening 34) of the groove 35 as indicated by an arrow F in FIG. 34 and flows into the second exhaust pipe 44 along the front inner surface (the inner surface located on the front side of the vehicle) of the second exhaust pipe 44 (as indicated by the broken line portion of the arrow F in FIG. 5). , Wrap around the bottom plate 33 and flow into the second exhaust pipe 44). For this reason, the exhaust gas flows smoothly from the opening 34 into the second manipulator 4, and the exhaust gas discharge performance is ensured satisfactorily. As a result, it is possible to suppress the pressure of the exhaust gas from increasing at the connecting portion between the first exhaust pipe 21 and the second exhaust pipe 44.

  The exhaust gas flowing into the second manipulator 4 is purified by the NSR catalyst 42, and after PM is collected by the DPF 43, it is released into the atmosphere.

  As described above, in the present embodiment, the exhaust pipes 21 and 44 are connected so as to overlap each other, and the exhaust system is made compact, but the grooves 35 formed in the bottom plate portion 33 of the connecting member 3 are aligned. By flowing the exhaust gas in this manner, the exhaust gas can be smoothly flowed from the opening 34 to the second manipulator 4. For this reason, the exhaust gas discharge performance is ensured satisfactorily, and it is possible to suppress the pressure of the exhaust gas from increasing at the connecting portion between the first exhaust pipe 21 and the second exhaust pipe 44. As a result, the engine performance can be fully exhibited. Further, as described above, since the exhaust gas flowing from the connecting member 3 into the second manipulator 4 has an arc-shaped flow, the exhaust gas mixing property is improved, and the deviation of the exhaust gas flow velocity and temperature is eliminated. This also ensures good exhaust gas discharge performance.

  In the present embodiment, since the NSR catalyst 42 is disposed inside the second exhaust pipe 44 in the region where the first exhaust pipe 21 and the second exhaust pipe 44 overlap as viewed from the first direction, The overlapping portion can be effectively used as a space for disposing the NSR catalyst 42, and exhaust purification performance can be improved by disposing a plurality of NSR catalysts 22,42.

  Moreover, since the connection member 3 which concerns on this embodiment was shape | molded by the lost wax casting of stainless steel, while being able to raise the freedom degree of the shape, improvement of corrosion resistance can be aimed at.

-Other embodiments-
In the embodiment described above, the case where the connecting member 3 is molded by stainless lost wax casting has been described. The material and manufacturing method of the connection member 3 are not limited to this, and can be selected as appropriate.

  In the above embodiment, the case where the present invention is applied to the exhaust system of a diesel engine mounted on a vehicle has been described. The present invention is not limited to this, and can also be applied to an exhaust system of an engine mounted on something other than a vehicle. Further, the present invention is applicable not only to the exhaust system of a diesel engine but also to the exhaust system of a gasoline engine.

  Further, the exhaust gas purification device accommodated in each of the manipulators 2 and 4 is not limited to that of the above embodiment. For example, a selective reduction catalyst (SCR catalyst), a three-way catalyst, or the like can be applied.

  The present invention can be applied to an exhaust pipe structure in which a plurality of exhaust pipes having different extending directions are connected by a connecting member.

21 First exhaust pipe 22 NSR catalyst (first exhaust purification device)
3 connecting member 33 bottom plate portion 34 opening 35 groove 42 NSR catalyst (second exhaust purification device)
44 Second exhaust pipe

Claims (3)

A first exhaust pipe extending along a first direction;
A second exhaust pipe that is located downstream of the first exhaust pipe in the exhaust gas flow direction and extends along a second direction intersecting the first direction;
A connecting member for connecting the exhaust pipes to each other so that the first exhaust pipe and the second exhaust pipe overlap each other when viewed from the first direction;
With
The connecting member includes an opening that communicates the inside of the first exhaust pipe and the inside of the second exhaust pipe, and is adjacent to the opening as viewed from the first direction and the first exhaust pipe and the second exhaust pipe. A bottom plate portion formed corresponding to an area where the exhaust pipe overlaps with the first direction, and a surface of the bottom plate portion facing the inner side of the first exhaust pipe has A structure of an exhaust pipe, wherein a groove extending toward the opening is formed along an outer edge portion of a bottom plate portion. The exhaust pipe structure according to claim 1,
While the first exhaust pipe is provided with a first exhaust purification device,
A second exhaust purification device is located inside the second exhaust pipe in a region where the first exhaust pipe and the second exhaust pipe overlap when viewed from the first direction. The structure of the tube. In the structure of the exhaust pipe according to claim 1 or 2,
The exhaust pipe structure is characterized in that the connecting member is molded by stainless lost wax casting.

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