Saddle-riding type vehicle

Abstract

To provide a saddle-riding type vehicle which enables improvement of flexibility of the layout of a space for placing a catalyst.SOLUTION: A saddle-riding type vehicle includes: a vehicle body frame including an engine mounting frame; an internal combustion engine mounted on the engine mounting frame and having an intake port and an exhaust port; a swing arm extending rearward from the engine mounting frame, the swing arm having a front end which is pivotally supported by a pivot shaft at a rear part of the engine mounting frame; a rear wheel connected to a rear end of the swing arm; and at least one exhaust assembly having an exhaust pipe connected to the exhaust port of the internal combustion engine, a muffler connected to the exhaust pipe, and at least one catalyst housed in an intermediate part of the exhaust pipe at the upstream side of the muffler. The pivot shaft is disposed at a higher level than a lower part of the engine mounting frame. The catalyst is disposed forward of the rear wheel, rearward of the internal combustion engine, and below the swing arm.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present disclosure relates to a saddle-ride vehicle having an exhaust pipe containing a catalyst. [Background technology]

[0002] Patent Document 1 discloses a saddle-ride vehicle having an exhaust pipe extending downward from an internal combustion engine and then rearward in the longitudinal direction of the vehicle. The saddle-ride vehicle of Patent Document 1 has an exhaust system in the exhaust pipe that includes a catalyst for purifying exhaust gas and an exhaust gas sensor for detecting the characteristics of the exhaust gas. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2019-194449 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the saddle riding vehicle disclosed in Patent Document 1, the exhaust pipe extends downward from the internal combustion engine and then extends along the front-rear direction of the vehicle, so the space for arranging the catalyst may be limited, which may limit the size of the catalyst to be arranged, and therefore the purification performance of the exhaust gas.

[0005] Therefore, an object of one aspect of the present disclosure is to provide a saddle-ride vehicle that allows for greater freedom in layout of the space in which the catalyst is disposed. [Means for solving the problem]

[0006] The saddle-riding vehicle of the present disclosure comprises a body frame including an engine mounting frame, an internal combustion engine mounted on the engine mounting frame and having an intake port and an exhaust port, a swing arm extending rearward from the engine mounting frame and having a front end supported by a pivot shaft on a rear portion of the engine mounting frame, a rear wheel connected to the rear end of the swing arm, and at least one exhaust assembly having an exhaust pipe connected to the exhaust port of the internal combustion engine, a muffler connected to the exhaust pipe, and at least one catalyst housed in an intermediate portion of the exhaust pipe upstream of the muffler, wherein the pivot shaft is positioned higher than a lower portion of the engine mounting frame, and the catalyst is positioned in front of the rear wheel, rear of the internal combustion engine, and below the swing arm. Effect of the Invention

[0007] According to the present disclosure, the catalyst is positioned in the space forward of the rear wheel, rear of the engine mounting frame, and below the swing arm, thereby improving the freedom of layout related to the catalyst even when a large catalyst is used. [Brief description of the drawings]

[0008] [Figure 1] 1 is a side view of a saddle riding vehicle according to a first embodiment of the present disclosure. [Diagram 2] 2 is a perspective view of the exhaust pipe and its periphery in the saddle riding vehicle of FIG. 1, as viewed obliquely from above. [Diagram 3] 2 is a perspective view of the periphery of an exhaust pipe of the saddle riding vehicle of FIG. 1, as viewed obliquely from below. [Figure 4] 2 is a perspective view of the periphery of an intermediate portion of an exhaust pipe of the saddle riding vehicle of FIG. 1, as viewed obliquely from above. [Diagram 5] 2 is a perspective view of the periphery of an intermediate portion of an exhaust pipe of the saddle riding vehicle of FIG. 1, as viewed from below. [Figure 6] 2 is a cross-sectional view of an intermediate portion of an exhaust pipe of the saddle riding vehicle of FIG. 1, as viewed from the left-right direction of the vehicle. [Figure 7]2 is a perspective view of the periphery of a middle portion of an exhaust pipe of the saddle riding vehicle of FIG. 1 with a step and a foot brake attached, as viewed obliquely from above. [Figure 8] FIG. 11 is a plan view showing a schematic view of only the exhaust assembly in a saddle riding vehicle according to a second embodiment of the present disclosure. [Figure 9] FIG. 11 is a plan view showing a schematic view of only the exhaust assembly in a saddle riding vehicle according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a saddle riding vehicle according to an embodiment will be described with reference to the attached drawings. In this specification, the front-rear direction, the left-right direction (lateral direction), and the up-down direction refer to directions seen from a rider when the rider is seated on the vehicle.

[0010] (First embodiment) FIG. 1 is a side view of a saddle riding vehicle 1 according to a first embodiment. As shown in FIG. 1, in this embodiment, the saddle riding vehicle 1 is a motorcycle. The saddle riding vehicle 1 is not limited to a motorcycle, and may be any vehicle on which a rider rides by straddling a seat, for example, a three-wheeled motor vehicle. The saddle riding vehicle 1 includes a front wheel 2, a rear wheel 3, and a body frame 4. The body frame 4 is supported by the front wheel 2 and the rear wheel 3. The body frame 4 includes a head pipe 4a, an engine mounting frame 4b connected to the head pipe 4a and disposed rearward of the head pipe 4a, and a seat support frame 4c connected to the engine mounting frame 4b and disposed rearward of the engine mounting frame 4b.

[0011] Specifically, the engine mounting frame 4b includes a main frame portion 4d extending rearward from the head pipe 4a, a down frame portion 4e extending downward from the head pipe 4a, a lower frame portion 4f extending rearward from a lower end portion of the down frame portion 4e, and a pivot frame portion 4g connecting the rear end portion of the main frame portion 4d to the rear end portion of the lower frame portion 4f. The saddle riding vehicle 1 includes a front fork 5 that connects the front wheel 2 and the body frame 4 and is provided between the front wheel 2 and the body frame 4. The front fork 5 is provided below the steering shaft 7 and connected to a bracket 8. The front fork 5 extends obliquely upward and rearward.

[0012] A front suspension 6 is provided on the front fork 5, and the front fork 5 is configured to be able to expand and contract in the longitudinal direction by elastic deformation of a spring inside the front suspension 6. The front fork 5 reduces shocks transmitted to the body frame 4 by expanding and contracting in the longitudinal direction. A steering shaft 7 connected to a bracket 8 is supported on a head pipe 4c that is a part of the body frame 4 so as to be able to change its angle. The saddle riding vehicle 1 also has a rear suspension 9 that connects the rear wheel 3 to the rear part of the body frame 4. The rear suspension 9 is configured to be able to absorb shocks input to the rear wheel 3 via a swing arm 10. The swing arm 10 that supports the rear wheel 3 and extends in the fore-and-aft direction is supported on the body frame 4 so as to be able to change its angle.

[0013] The steering shaft 7 is provided with a handlebar 11 that is gripped by the rider's hands. A fuel tank 22 is provided behind the handlebar 11. A seat 13 on which a rider sits is provided behind the fuel tank 22. The saddle riding vehicle 1 is provided with an internal combustion engine E as a drive source that generates power transmitted to the wheels. The internal combustion engine E is supported by an engine mounting frame 4a between the front wheel 2 and the rear wheel 3. Specifically, the internal combustion engine E is disposed below the main frame portion 4d, behind the down frame portion 4e, above the lower frame portion 4f, and in front of the pivot frame portion 4g. In this embodiment, the internal combustion engine E functions as a prime mover that generates a rotational drive force that is transmitted to the rear wheel 3.

[0014] The internal combustion engine E includes a cylinder Ea and a crankcase Eb disposed below the cylinder Ea. The crankcase Eb houses a transmission 14 that changes the speed of the power output from the internal combustion engine E. The transmission 14 has an input shaft 14a, an output shaft 14b, and a plurality of gear trains (not shown) with different reduction ratios. The transmission 14 is configured to be able to transmit power from the input shaft 14a to the output shaft 14b via the gear train, and selects an arbitrary one of the gear trains to change the speed. The power output from the internal combustion engine E via the transmission 14 is transmitted to the rear wheel 3 via an output transmission structure 15 such as a chain or a belt. Note that the driving force output from the internal combustion engine E is not necessarily transmitted to the rear wheel 3 via a chain, but may be transmitted by another power transmission member such as a belt.

[0015] The swing arm 10 extends in the vehicle front-rear direction and extends rearward from a pivot shaft 12 connected to the rear of the engine mounting frame 4a. Specifically, the front end of the swing arm 10 is journaled by the pivot shaft 12 supported by the pivot frame portion 4g. The pivot shaft 12 is disposed rearward of the internal combustion engine E. The swing arm 10 swings up and down about the portion journaled by the pivot shaft 12. The rear wheel 3 is journaled by the rear end of the swing arm 10 and connected to the swing arm 10. The pivot shaft 12 is disposed at a position higher than the lower portion of the engine mounting frame 4a. Specifically, the pivot shaft 12 is disposed at a position higher than the lower end of the lower frame portion 4f. More specifically, the pivot shaft 12 is disposed at a position higher than the lower end of the crankcase Eb.

[0016] The internal combustion engine E has an intake port 16 and an exhaust port 17. When the internal combustion engine E is driven, it takes in intake air from the intake port 16 and discharges exhaust gas from the exhaust port 17. For example, a case where the internal combustion engine E has one cylinder will be described. Since the internal combustion engine E has one cylinder, the internal combustion engine E has one intake port and one exhaust port corresponding to the one cylinder. In addition, when the internal combustion engine E has multiple cylinders, each cylinder may have an intake port and an exhaust port. For example, when the internal combustion engine E has four cylinders, the internal combustion engine E may have four intake ports and four exhaust ports. The number of cylinders of the internal combustion engine E may be five or more, or may be two or three. In that case, the internal combustion engine E may have the number of intake ports and exhaust ports corresponding to the number of cylinders.

[0017] The saddle riding vehicle 1 includes an exhaust assembly 18. The exhaust assembly 18 includes an exhaust pipe 20, a muffler 21, and a catalyst 23. The exhaust pipe 20 extends downward from an exhaust port 17 of the internal combustion engine E, turns rearward in the front-rear direction below the internal combustion engine E, and then extends rearward from there. The exhaust pipe 20 guides exhaust gas discharged from the exhaust port 17 of the internal combustion engine E rearward. In this embodiment, the exhaust pipe 20 is configured by one pipe, but when the internal combustion engine E has multiple cylinders, an exhaust manifold having a branch portion configured by pipes in a number corresponding to the number of cylinders of the internal combustion engine E may be used as the exhaust pipe 20.

[0018] A side cover 23 is disposed on the outer lateral side of the exhaust pipe 20 in the left-right direction so as to cover the outer lateral side of the exhaust pipe 20 in a part of the front-rear direction of the exhaust pipe 20. A muffler 21 is connected to a downstream end 20b of the exhaust pipe 20. That is, the muffler 21 muffles exhaust noise of exhaust gas that flows from the internal combustion engine E through the exhaust pipe 20 into the muffler 21. An exhaust port 21d is provided at the downstream end 21b of the muffler 21. The exhaust gas that passes through the muffler 21 is discharged into the atmosphere from the exhaust port 21d.

[0019] Fig. 2 shows an enlarged perspective view of the periphery of exhaust pipe 20 as viewed from diagonally above. In Fig. 2, side cover 29, which will be described later, is indicated by a two-dot chain line so that the side cover 29 can be seen through. Fig. 3 shows an enlarged perspective view of the periphery of exhaust pipe 20 as viewed from below.

[0020] 2 and 3, the exhaust pipe 20 includes an upstream portion 20d, an intermediate portion 20e, and a downstream portion 20f. The upstream portion 20d of the exhaust pipe 20 extends in the front-rear direction of the saddle riding vehicle 1 upstream of the intermediate portion 20e, and connects the exhaust port 17 of the internal combustion engine E to the intermediate portion 20e. The upstream portion 20d of the exhaust pipe 20 passes below the internal combustion engine E. The downstream portion 20f of the exhaust pipe 20 extends in the front-rear direction of the saddle riding vehicle 1 downstream of the intermediate portion 20e, and connects the intermediate portion 20e to the muffler 21. The downstream end of the upstream portion 20d and the upstream end of the downstream portion 20f are disposed outside the body frame 4 in the left-right direction of the vehicle.

[0021] The intermediate portion 20e is disposed at a position closer to a center line L1 extending in the front-rear direction passing through the center in the left-right direction of the saddle riding vehicle 1 than at least one of the upstream portion 20d and the downstream portion 20f in the left-right direction of the saddle riding vehicle 1. The intermediate portion 20e is disposed at a position closer to the center in the left-right direction than both the upstream portion 20d and the downstream portion 20f in the left-right direction of the saddle riding vehicle 1. The intermediate portion 20e protrudes from the upstream portion 20d and the downstream portion 20f toward the inside in the left-right direction of the saddle riding vehicle 1.

[0022] At the upstream portion 20d, the exhaust pipe 20 extends downward from a position connected to the exhaust port 17 of the internal combustion engine E, and then extends rearward in the fore-and-aft direction. At the intermediate portion 20e, the exhaust pipe 20 is bent so as to extend from the upstream portion 20d toward the center in the left-right direction of the saddle riding vehicle 1. The intermediate portion 20e of the exhaust pipe 20 extends from the upstream portion 20d toward the center in the left-right direction of the saddle riding vehicle 1, then bends toward the outside in the opposite direction, extends toward the outside in the left-right direction of the saddle riding vehicle 1, and is connected to the downstream portion 20f. In other words, the intermediate portion 20e of the exhaust pipe 20 has a U-shape.

[0023] A catalyst 23 is housed inside the intermediate portion 20e of the exhaust pipe 20. The catalyst 23 is disposed in front of the rear wheel 3, behind the internal combustion engine E, and below the swing arm 10. In particular, in this embodiment, the catalyst 23 is disposed behind the engine mounting frame 4a.

[0024] The position of the swing arm 10 shown in Fig. 3 is at the lower limit in the up-down direction. The swing arm 10 is configured to be able to rotate upward from the lower limit state shown in Fig. 3 around the pivot shaft 12 as shown by the arrow D1. When the swing arm 10 is at the lower limit position shown in Fig. 3, a gap G1 is secured between the swing arm 10 and the intermediate portion 20e in the up-down direction. Therefore, even if the swing arm 10 rotates around the pivot shaft 12, a gap is secured between the swing arm 10 and the intermediate portion 20e, and they are configured not to interfere with each other.

[0025] Fig. 4 shows an enlarged perspective view of the intermediate portion 20e of the exhaust pipe 20 as viewed obliquely from above. Fig. 5 shows an enlarged perspective view of the intermediate portion 20e of the exhaust pipe 20 as viewed obliquely from below. The catalyst 23 is filled inside a portion of the intermediate portion 20e of the exhaust pipe 20 where flow path axes L2 and L3, which will be described later, extend along the left-right direction of the saddle riding vehicle 1.

[0026] As described above, the upstream portion 20d and the downstream portion 20f of the exhaust pipe 20 are disposed on one side in the left-right direction with respect to the body frame 4. In this embodiment, the upstream portion 20d and the downstream portion 20f of the exhaust pipe 20 are disposed on the right side of the rear wheel 3 in the left-right direction of the saddle riding vehicle 1. The middle portion 20e of the exhaust pipe 20 has a first portion 20g connected to the upstream portion 20d and extending from the upstream portion 20d toward the other side (left side) in the left-right direction, a second portion 20h curved rearward and upward from the first portion 20g, and a third portion 20k extending from the second portion 20h toward one side (right side) in the left-right direction and connected to the downstream portion 20f. The flow path axes of the first portion 20g and the third portion 20k have portions that extend linearly along the left-right direction of the vehicle. 4, the flow path axis of the linearly extending portion of the first portion 20g is designated as L2, and the flow path axis of the linearly extending portion of the third portion 20k is designated as L3. The catalyst housed in the first portion 20g of the intermediate portion 20e is designated as the first catalyst 23a, and the catalyst housed in the third portion 20k of the intermediate portion 20e is designated as the second catalyst 23b. In the region of the intermediate portion 20e where the catalyst 23 is arranged, the exhaust pipe 20 has a straight shape so that the flow path cross-sectional area is constant.

[0027] The first portion 20g and the third portion 20k in the intermediate portion 20e of the exhaust pipe 20 are disposed at different heights. That is, the third portion 20k in the intermediate portion 20e is disposed at a higher position than the first portion 20g. Specifically, in the intermediate portion 20e of the exhaust pipe 20, the third portion 20k is disposed rearward and above the first portion 20g.

[0028] 5, the saddle riding vehicle 1 further includes an oxygen sensor 35 disposed at a position downstream of the catalyst 23. In this embodiment, the oxygen sensor 35 is attached to the middle portion 20e of the exhaust pipe 20. The oxygen sensor 35 is attached by being inserted from the lower surface of the exhaust pipe 20 toward the flow path of the exhaust pipe 20.

[0029] FIG. 6 shows a cross-sectional view of the first portion 20g and the third portion 20k of the intermediate portion 20e of the exhaust pipe 20, taken along a plane perpendicular to the direction in which the exhaust pipe 20 extends. As shown in FIGS. 3 to 6, the saddle riding vehicle 1 includes a heat shielding cover 24 that covers the intermediate portion 20e of the exhaust pipe 20. The heat shielding cover 24 is disposed with a gap G2 from the intermediate portion 20e of the exhaust pipe 20. In this embodiment, the heat shielding cover 24 is disposed with a gap G2 from the intermediate portion 20e over the entire intermediate portion 20e. In this embodiment, a bracket 25 is attached between the intermediate portion 20e of the exhaust pipe 20 and the heat shielding cover 24 so as to be connected to both the intermediate portion 20e and the heat shielding cover 24, thereby supporting the heat shielding cover 24 on the intermediate portion 20e while maintaining the gap G2 between the intermediate portion 20e and the heat shielding cover 24. As shown in FIG. 6, the bracket 25 is connected to the heat shielding cover 24 by fastening a bolt 26 and a nut 27. In this embodiment, the bolt 26 is inserted into the heat shield cover 24 in a rearward-forward direction D2 at a rearward position of the heat shield cover 24, and is fastened to the nut 27 inside the heat shield cover 24. In addition, the bracket 25 is connected to the third portion 20k in the intermediate portion 20e of the exhaust pipe 20 from below by welding, adhesive, or the like.

[0030] The heat shield cover 24 has a plurality of recesses 28 formed on its surface. The heat shield cover 24 has a recess 28a formed on its surface facing upward and a recess 28b formed on its surface facing downward. The plurality of recesses 28 are, for example, a plurality of grooves extending in the front-rear direction of the vehicle. Since the bolt 26 is provided on the lower side of the heat shield cover 24, the recess 28b is formed so as to avoid the position where the bolt 26 is arranged. On the upper side of the heat shield cover 24, the recess 28a is formed at a position close to the center in the front-rear direction. Since the recess 28a and the recess 28b are formed in the heat shield cover 24, the surface area (heat dissipation area) of the portion of the heat shield cover 24 facing the outside can be increased. Therefore, even if the heat from the exhaust gas is transferred to the heat shield cover 24 via the exhaust pipe 20 and the heat shield cover 24 becomes hot, the heat of the heat shield cover 24 can be suitably dissipated to the outside. Therefore, excessive heat accumulation inside the heat shield cover 24 can be suppressed.

[0031] The connection structure between the heat shield cover 24 and the exhaust pipe 20 is not limited to the above embodiment, and other configurations may be adopted for the connection between the heat shield cover and the exhaust pipe as long as the heat shield cover is connected to the exhaust pipe while a gap is secured between the heat shield cover and the exhaust pipe.

[0032] The middle portion 20e of the exhaust pipe 20 is not directly connected to any other components such as the body frame 4. Therefore, the middle portion 20e is not supported by the body frame 4 or other components. In the exhaust assembly 18, the upstream end portion 20a of the exhaust pipe 20 is connected to and supported by the internal combustion engine E, and the muffler 21 is supported by the body frame 4. Since the exhaust pipe 20 is not supported around the middle portion 20e, when vibration occurs in the exhaust pipe 20 including the middle portion 20e, the stress of the exhaust pipe 20 due to the vibration can be released. Therefore, the load acting on the exhaust pipe 20 can be kept small.

[0033] 4 and 5, in this embodiment, the saddle riding vehicle 1 includes a side cover 29 that spans the upstream portion 20d and the downstream portion 20f and covers the upstream portion 20d and the downstream portion 20f from one side in the left-right direction. The side cover 29 covers the gap 30 between the first portion 20g and the third portion 20k in the intermediate portion 20e from one side in the left-right direction. The side cover 29 covers the gap 30 between the first portion 20g and the third portion 20k in the intermediate portion 20e from the right side of the saddle riding vehicle 1.

[0034] Since the side cover 29 spans the upstream portion 20d and the downstream portion 20f, a person looking at the saddle riding vehicle 1 from the side is given the visual impression that the upstream portion 20d and the downstream portion 20f of the exhaust pipe are continuous, thereby improving the design of the saddle riding vehicle 1.

[0035] 5, the side cover 29 is detachably attached to the exhaust pipe 20. For example, a clamp 31 fixed to a front part of the inner surface of the side cover 29 is engaged with the upstream portion 20d of the exhaust pipe 20, and a clamp 32 fixed to a rear part of the inner surface of the side cover 29 is engaged with the downstream portion 20e of the exhaust pipe 20.

[0036] The catalyst 23 purifies the exhaust gas by contacting it with the exhaust gas flowing inside the exhaust pipe 20. To use the catalyst 23 efficiently, it is preferable that the flow of the exhaust gas is uniform and there is no bias in the flow rate in the cross section of the exhaust pipe 20. If there is a local bias in the flow rate of the exhaust gas in the cross section of the exhaust pipe, the catalyst may exceed the limit of its exhaust gas purification processing capacity in a portion where a large amount of exhaust gas flows, and may not be able to sufficiently purify all the exhaust gas in that portion. Also, in a portion where the exhaust gas flow rate is low, the catalyst may purify only a small amount of exhaust gas compared to the purification processing capacity of the catalyst, and the catalyst may not be used sufficiently.

[0037] As shown in FIG. 4, in this embodiment, in order to ensure that the exhaust gas flows toward the catalyst 23 uniformly and without bias in the radial direction, the flow path cross-sectional area at the corner portion 20m of the exhaust pipe 20 increases toward the downstream side at least in a portion along the flow path axis of the corner portion 20m.

[0038] The flow passage cross-sectional area of ​​the curved corner portion 20m connecting the upstream portion 20d to the intermediate portion 20e of the exhaust pipe 20 increases toward the downstream side at least in a portion along the flow passage axis of the corner portion 20m. In this embodiment, the flow passage cross-sectional area of ​​the corner portion 20m increases toward the downstream side along the entire flow passage axis of the corner portion 20m. The corner portion 20m of the exhaust pipe 20 is configured so that the rate of increase in the flow passage cross-sectional area is largest at a position where the flow passage axis of the corner portion 20m is bent at 45 degrees with respect to the flow passage axis of the upstream portion 20d. When the flow passage axis of the corner portion 20m passes the position where it is bent at 45 degrees with respect to the flow passage axis of the upstream portion 20d, the rate of increase in the flow passage cross-sectional area gradually decreases.

[0039] In this embodiment, the curved corner portion 20m connecting the upstream portion 20d to the intermediate portion 20e is configured to be bent at 90 degrees, and the flow path cross-sectional area increases at the corner portion 20m, and the rate of increase in the flow path cross-sectional area becomes largest when the exhaust pipe 20 is bent at 45 degrees, which is half the bending angle of the corner portion 20m. However, the bending angle of the corner portion 20m is not limited to 90 degrees. The bending angle of the corner portion 20m may be an angle other than 90 degrees. In that case, it is sufficient that the flow path cross-sectional area of ​​the corner portion 20m is configured to gradually increase toward the downstream side and the rate of increase in the flow path cross-sectional area becomes largest at the middle position of the corner portion 20m. For example, when the corner portion 20m is 120 degrees, the flow path cross-sectional area of ​​the corner portion 20m may be configured to gradually increase toward the downstream side and the rate of increase in the flow path cross-sectional area becomes largest when the exhaust pipe 20 is bent at 60 degrees.

[0040] FIG. 4 shows a flow section S1 of the exhaust pipe 20 at a position bent at 0 degrees with respect to the flow axis of the upstream portion 20d, a flow section S2 of the exhaust pipe 20 at a position bent at 45 degrees with respect to the flow axis of the upstream portion 20d, and a flow section S3 of the exhaust pipe 20 at a position bent at 90 degrees with respect to the flow axis of the upstream portion 20d. Comparing the flow section S1, the flow section S2, and the flow section S3, the corner portion 20m is configured so that the cross-sectional area of ​​the flow section gradually increases toward the downstream side, so that the cross-sectional area of ​​the flow section S2 is larger than the cross-sectional area of ​​the flow section S1, and the cross-sectional area of ​​the flow section S3 is larger than the cross-sectional area of ​​the flow section S2. In addition, after the flow section S2, the cross-sectional area increases toward the downstream side, but the rate at which the cross-sectional area increases decreases toward the downstream side. By forming the shape of the corner portion 20m in this way, the centrifugal force acting on the exhaust gas when the exhaust gas passes through the corner portion 20m can be reduced. This allows the exhaust gas to flow inside the exhaust pipe 20 while preventing the exhaust gas from becoming biased within the cross section of the flow path when the exhaust gas passes through the straight pipe portion after passing through the corner portion 20m.

[0041] FIG. 7 is a perspective view showing the periphery of the middle portion 20e of the exhaust pipe 20 with the step 33 and the foot brake 34 attached. In this embodiment, the saddle riding vehicle 1 further includes the step 33 on which the rider places his / her foot and the foot brake 34 operated by the rider's foot. As shown in FIG. 7, in this embodiment, the foot brake 34 is disposed outside the side cover 29 in the left-right direction and disposed on one side (right side) of the side cover 29 in the left-right direction. In addition, the step 33 is disposed outside the foot brake 34 in the left-right direction and disposed on one side (right side) of the foot brake 34 in the left-right direction. Therefore, the step 33 is disposed on one side (right side) of the side cover 29 in the left-right direction. In addition, the step 33 is disposed vertically above the side cover 29 in a side view of the vehicle.

[0042] According to the configuration described above, the catalyst 23 is disposed in the space below the swing arm 10, in front of the rear wheel 3 and behind the internal combustion engine E, so that even when a large catalyst 23 is used, the catalyst 23 can be mounted on the saddle riding vehicle 1 while preventing the exhaust pipe 20 housing the catalyst 23 from interfering with other components. This improves the degree of freedom in the layout related to the catalyst 23.

[0043] In addition, since the middle portion 20e of the exhaust pipe 20 is disposed closer to the center in the left-right direction of the vehicle than the upstream portion 20d and the downstream portion 20f, the portion of the exhaust pipe 20 that houses the catalyst 23 is less likely to be seen from outside the vehicle, thereby improving the appearance of the saddle riding vehicle 1. Furthermore, in the case where the saddle riding vehicle 1 is a lean vehicle, it is possible to prevent the middle portion 20e of the exhaust pipe 20 from interfering with the ground when the vehicle is lean.

[0044] In addition, the flow passage axes L2 and L3 of the portion of the intermediate portion 20e of the exhaust pipe 20 filled with the catalyst 23 are aligned along the left-right direction of the saddle riding vehicle 1, so that the space in front of the rear wheel 3, behind the engine mounting frame 4a and below the swing arm 10 can be fully utilized in the left-right direction of the saddle riding vehicle 1. Therefore, the layout efficiency of the saddle riding vehicle 1 can be improved.

[0045] In addition, because the middle section 20e of the exhaust pipe 20 has a U-shape, a sufficient volume of catalyst can be accommodated while maintaining a compact layout of the exhaust pipe 20. Because the middle section 20e of the exhaust pipe 20 has a U-shape, the straight section can be made long without making the entire middle section 20e long in the left-right direction of the vehicle, and the volume of the section in which the catalyst 23 can be disposed can be increased accordingly.

[0046] Furthermore, since the middle portion 20e of the exhaust pipe 20 has a U-shape, and the catalyst 23 is housed in each of the first portion 20g and the second portion 20k extending in the left-right direction of the middle portion 20e, it is possible to house a sufficient volume of catalyst in the middle portion 20e of the exhaust pipe 20, while not having to house the catalyst 23 in the curved portion of the exhaust pipe 20, thereby promoting a stable and uniform catalytic reaction.

[0047] In addition, since the first portion 20g and the third portion 20k in the intermediate portion 20e of the exhaust pipe 20 are disposed at different heights, the first portion 20g and the third portion 20k can be disposed close to each other in the vehicle longitudinal direction, and the clearance between the intermediate portion 20e of the exhaust pipe 20 and the rear wheel 3 in the vehicle longitudinal direction can be increased. Therefore, the degree of freedom in the layout of the saddle riding vehicle 1 can be further improved.

[0048] Furthermore, since the downstream third portion 20k of the intermediate portion 20e of the exhaust pipe 20, which is the upstream first portion 20g and the downstream third portion 20k, is disposed higher than the upstream first portion 20g, the downstream side of the exhaust pipe 20 can be disposed higher without causing strain on the layout of the exhaust pipe 20. Therefore, the muffler 21 can be disposed higher while the exhaust pipe 20 is laid out efficiently.

[0049] In addition, since the side cover 29 covers the gap 30 between the first portion 20g and the third portion 20k of the intermediate portion 20e from one side (the right side) in the left-right direction of the saddle riding vehicle 1, the side cover 29 can hide the gap 30 between the first portion 20g and the third portion 20k of the intermediate portion 20e from the outside in the left-right direction of the vehicle. Therefore, when the exhaust pipe 20 is viewed from the outside in the left-right direction of the vehicle, the upstream portion 20d and the downstream portion 20f appear to be continuous with each other, thereby improving the external appearance of the vehicle.

[0050] In addition, because the step 33 is located to one side (right side) of the side cover 29 in the left-right direction, when the rider places his / her feet on the step 33, the side cover 29 is positioned between the rider's feet and the exhaust pipe 20. Therefore, the side cover 29 functions as a heat guard to protect the rider's feet from the heat of the exhaust pipe 20.

[0051] In addition, because the flow path cross-sectional area of ​​the corner portion 20m in the exhaust pipe 20 increases toward the downstream side at least in a portion along the flow path axis of the corner portion 20m, the flow speed of the exhaust gas that reaches the corner portion 20m from the upstream portion 20d is slowed down due to the increase in the flow path cross-sectional area, and the centrifugal force of the exhaust gas passing through the corner portion 20m is weakened. Therefore, it is possible to prevent the occurrence of bias in the flow speed of the exhaust gas passing through the corner portion 20m within the cross section of the corner portion 20m, and thereby it is possible to prevent the exhaust gas that flows from the corner portion 20m to the intermediate portion 20e from partially passing through the catalyst 23 and biasing the catalytic reaction.

[0052] In addition, because the heat shielding cover 24 covers the intermediate portion 20e and is disposed with the gap G2 from the intermediate portion 20e, it is possible to prevent the heat of the catalyst 23 from being directly transferred to the surrounding components through heat transfer. This makes it possible to prevent localized heat transfer from the catalyst 23 to the outside of the heat shielding cover 24. For example, even if electronic components or the like that are sensitive to heat are disposed above the position where the catalyst 23 is disposed, the heat shielding cover 24 can protect those components from heat.

[0053] In addition, since the oxygen sensor 35 is attached to the middle portion 20e of the exhaust pipe 20, the oxygen sensor 35 is attached to a position of the exhaust pipe 20 close to the center in the left-right direction of the saddle riding vehicle 1. Therefore, when the saddle riding vehicle 1 is viewed from the side, the oxygen sensor 35 is less likely to be visible from outside the vehicle, and the external appearance of the vehicle can be improved.

[0054] In the above embodiment, the corner portion 20m where the upstream portion 20d is connected to the intermediate portion 20e is configured so that the flow cross-sectional area increases toward the downstream and the rate of increase in the flow cross-sectional area is maximized at the intermediate position where the upstream portion 20d is bent at 45 degrees. However, the present invention is not limited to the above embodiment. In addition to the corner portion 20m where the upstream portion 20d is connected to the intermediate portion 20e, other corner portions may be configured so that the flow cross-sectional area increases toward the downstream and the rate of increase in the flow cross-sectional area is maximized at the intermediate position of the corner portion. For example, in the intermediate portion 20e of the exhaust pipe 20, the corner portion from the second portion 20h to the third portion 20k after passing through the first catalyst 23a may be configured so that the flow cross-sectional area increases toward the downstream and the rate of increase in the flow cross-sectional area is maximized at the intermediate position of the corner portion. In this way, the flow velocity of the exhaust gas flowing into the second catalyst 23b can be made uniform without bias within the cross section of the exhaust pipe 20, the second catalyst 23b can be used efficiently throughout the entire cross section of the exhaust pipe 20, and the exhaust gas purification ability can be improved. Also, in other portions of the exhaust pipe 20, the flow passage cross-sectional area may be configured to increase toward the downstream side, with the rate of increase in the flow passage cross-sectional area being greatest at the middle position of the corner portion.

[0055] Second embodiment Next, a saddle riding vehicle according to a second embodiment will be described. Descriptions of parts common to the first embodiment will be omitted. The second embodiment differs from the first embodiment in that exhaust assemblies are provided on both the left and right sides of the vehicle in the left-right direction, and both exhaust assemblies are provided with intermediate portions of exhaust pipes.

[0056] 8 shows a plan view of only the exhaust assembly of the saddle riding vehicle 1a in the second embodiment. In the second embodiment, for example, the internal combustion engine E has two cylinders, and therefore the internal combustion engine E has two exhaust ports. Therefore, in the second embodiment, the saddle riding vehicle 1a has a first exhaust assembly 37 and a second exhaust assembly 38 that correspond to the two exhaust ports of the internal combustion engine E and are disposed on the left and right sides of the saddle riding vehicle 1a, respectively.

[0057] The first exhaust assembly 37 is connected to the exhaust port of the internal combustion engine E, and guides exhaust gas discharged from the exhaust port of the internal combustion engine E rearward. The first exhaust assembly 37 has an exhaust pipe 39, a muffler 40, and a catalyst 41. The exhaust pipe 39 is connected to the exhaust port of the internal combustion engine E, extends downward from the exhaust port, turns rearward in the front-to-rear direction below the internal combustion engine E, and extends rearward from there.

[0058] The exhaust pipe 39 includes an upstream portion 39a, an intermediate portion 39b, and a downstream portion 39c. The upstream portion 39a of the exhaust pipe 39 extends in the front-rear direction of the saddle riding vehicle 1a upstream of the intermediate portion 39b. The downstream portion 39c of the exhaust pipe 39 extends in the front-rear direction of the saddle riding vehicle 1a downstream of the intermediate portion 39b. The upstream portion 39a and the downstream portion 39c are disposed at approximately the same position in the left-right direction of the saddle riding vehicle 1. The intermediate portion 39b is disposed at a position upstream of the muffler 40.

[0059] The intermediate portion 39b protrudes from the upstream portion 39a and the downstream portion 39c toward a center line L4 extending in the front-rear direction of the saddle riding vehicle 1a in the left-right direction of the saddle riding vehicle 1a. The shape of the intermediate portion 39b is substantially the same as that of the intermediate portion 20e of the first embodiment, but the entire intermediate portion 39b is disposed on one side in the left-right direction of the center line L4. In other words, the intermediate portion 39b has a size in the left-right direction of the vehicle such that it does not straddle the center line L4.

[0060] A catalyst 41 is accommodated inside the intermediate portion 39b of the exhaust pipe 39. The catalyst 41 is filled inside a portion of the intermediate portion 39b of the exhaust pipe 39 where the flow path axes L5 and L6 extend along the left-right direction of the saddle riding vehicle 1a. The intermediate portion 39b of the exhaust pipe 39 is covered with a heat insulating cover 42 with a gap therebetween.

[0061] The second exhaust assembly 38 has a shape symmetrical to the first exhaust assembly 37. The second exhaust assembly 38 has an exhaust pipe 43, a muffler 44, and a catalyst 45. The exhaust pipe 42 is connected to an exhaust port of the internal combustion engine E, extends downward from the exhaust port, turns rearward in the front-to-rear direction below the internal combustion engine E, and extends rearward from there.

[0062] The intermediate portion 43b protrudes from the upstream portion 43a and the downstream portion 43c toward the center line L4 in the left-right direction of the saddle riding vehicle 1a. The shape of the intermediate portion 43b is substantially the same as that of the intermediate portion 20e of the first embodiment, but the entire intermediate portion 43b is disposed on the other side in the left-right direction from the center line L4. In other words, the intermediate portion 43b has a size in the left-right direction of the vehicle such that it does not straddle the center line L4.

[0063] A catalyst 45 is housed inside the intermediate portion 43b of the exhaust pipe 43. In this embodiment, the catalyst 45 is filled inside a portion of the intermediate portion 43b of the exhaust pipe 43 where the flow path axes L7 and L8 extend along the left-right direction of the saddle riding vehicle 1a. The intermediate portion 43b of the exhaust pipe 43 is covered with a heat insulating cover 46 with a gap therebetween.

[0064] In this embodiment, the heat insulating cover 42 of the first exhaust assembly 37 and the heat insulating cover 46 of the second exhaust assembly 38 abut against each other at a position close to the center in the left-right direction of the saddle riding vehicle 1a, but they do not have to abut against each other. Also, the middle portion 39b of the exhaust pipe 39 of the first exhaust assembly 37 and the middle portion 43b of the exhaust pipe 43 of the second exhaust assembly 38 face each other in the left-right direction of the saddle riding vehicle 1.

[0065] According to this embodiment, the first exhaust assembly 37 and the second exhaust assembly 38 are arranged symmetrically, so that the middle portion 39b of the exhaust pipe 39 in the first exhaust assembly 37 and the middle portion 43b of the exhaust pipe 43 in the second exhaust assembly 38 can be arranged at the same position in the front-rear direction. Therefore, the space of the saddle riding vehicle 1a can be used efficiently, and even when the saddle riding vehicle 1a is provided with a pair of left and right exhaust assemblies, the degree of freedom of layout related to the catalysts 41, 45 can be improved.

[0066] Third embodiment Next, a saddle riding vehicle according to a third embodiment will be described. Descriptions of parts common to the first and second embodiments will be omitted. The third embodiment differs from the first and second embodiments in that two exhaust assemblies are provided and arranged so that the exhaust pipes of the two exhaust assemblies intersect.

[0067] 9 is a plan view showing only the exhaust assembly of a saddle riding vehicle 1b in the third embodiment. In the third embodiment, as in the second embodiment, the internal combustion engine E has two exhaust ports. Therefore, in the third embodiment, the saddle riding vehicle 1b also has a first exhaust assembly 47 and a second exhaust assembly 48 corresponding to the two exhaust ports of the internal combustion engine E.

[0068] The first exhaust assembly 47 is connected to the exhaust port of the internal combustion engine E, and guides exhaust gas discharged from the exhaust port of the internal combustion engine E rearward. The first exhaust assembly 47 has an exhaust pipe 49, a muffler 50, and a catalyst 51. The exhaust pipe 49 is connected to the exhaust port of the internal combustion engine E, extends downward from the exhaust port, turns rearward in the front-to-rear direction below the internal combustion engine E, and extends rearward from there.

[0069] The exhaust pipe 49 includes an upstream portion 49a, an intermediate portion 49b, and a downstream portion 49c. The upstream portion 49a of the exhaust pipe 49 extends in the front-rear direction of the saddle riding vehicle 1b upstream of the intermediate portion 49b. The upstream portion 49a of the first exhaust assembly 47 is disposed on the left side of the saddle riding vehicle 1b. The downstream portion 49c of the exhaust pipe 49 is disposed on the opposite side of the upstream portion 49a with respect to the center line L9 of the saddle riding vehicle 1b in the left-right direction of the saddle riding vehicle 1b, and extends in the front-rear direction of the saddle riding vehicle 1b downstream of the intermediate portion 49b. The downstream portion 49c is disposed on the right side of the saddle riding vehicle 1b. The intermediate portion 39b is disposed in a position upstream of the muffler 50. The muffler 50 is connected to the downstream end of the downstream portion 49c of the exhaust pipe 49. Therefore, the muffler 50 is disposed at a position opposite to the upstream portion 49a with respect to the center line L9 of the saddle riding vehicle 1b in the left-right direction of the saddle riding vehicle 1b.

[0070] The intermediate portion 49b passes through the center line L9 and extends from one side to the other side of the saddle riding vehicle 1b, and in this embodiment, the intermediate portion 49b extends from the left side to the right side of the saddle riding vehicle 1b as it approaches the downstream side. As a result, the intermediate portion 49b extends in the left-right direction to bridge between the upstream portion 49a and the downstream portion 49c.

[0071] In this embodiment, the exhaust pipe 49 is connected to the exhaust port of the internal combustion engine E at a position on the left side in the left-right direction, extends downward from there, and then extends toward the rear in the front-rear direction of the saddle riding vehicle 1b. When the exhaust pipe 49 reaches a middle position in the front-rear direction, it bends so as to extend from the left side to the right side in the left-right direction of the saddle riding vehicle 1b as it heads downstream. In addition, the exhaust pipe 49 extends toward the right side in the left-right direction of the saddle riding vehicle 1b, and when it reaches the position of a downstream portion 49c, it bends so as to extend toward the rear in the front-rear direction of the saddle riding vehicle 1b.

[0072] A catalyst 51 is accommodated inside the intermediate portion 49b of the exhaust pipe 49. In the present embodiment, the catalyst 51 is filled inside a portion of the intermediate portion 49b of the exhaust pipe 49 where the flow path axis L10 extends along the left-right direction of the saddle riding vehicle 1b.

[0073] The second exhaust assembly 48 has an exhaust pipe 52, a muffler 53, and a catalyst 54. The exhaust pipe 52 is connected to an exhaust port of the internal combustion engine E, extends downward from the exhaust port, turns rearward in the front-to-rear direction below the internal combustion engine E, and then extends rearward from there.

[0074] The exhaust pipe 52 includes an upstream portion 52a, an intermediate portion 52b, and a downstream portion 52c. The upstream portion 52a of the exhaust pipe 52 extends in the front-rear direction of the saddle riding vehicle 1b upstream of the intermediate portion 52b. The upstream portion 52a of the second exhaust assembly 48 is disposed on the right side of the saddle riding vehicle 1b. The downstream portion 52c of the exhaust pipe 52 is disposed in a position opposite to the upstream portion 52a with respect to the center line L9 of the saddle riding vehicle 1b in the left-right direction of the saddle riding vehicle 1b, and extends in the front-rear direction of the saddle riding vehicle 1b downstream of the intermediate portion 52b. In this embodiment, the downstream portion 52c is disposed on the left side of the saddle riding vehicle 1b. The intermediate portion 52b is disposed in a position upstream of the muffler 53. The muffler 53 is connected to the downstream end of the downstream portion 52c of the exhaust pipe 52. Therefore, the muffler 53 is disposed at a position opposite to the upstream portion 52a with respect to the center line L9 of the saddle riding vehicle 1b in the left-right direction of the saddle riding vehicle 1b.

[0075] The intermediate portion 52b passes through the center line L9 and extends from the other side to the one side of the saddle riding vehicle 1b. In this embodiment, the intermediate portion 52b extends from the right side to the left side of the saddle riding vehicle 1b as it moves downstream. As a result, the intermediate portion 52b extends in the left-right direction to bridge between the upstream portion 52a and the downstream portion 52c. The intermediate portion 52b of the exhaust pipe 52 is disposed offset in the vehicle front-rear direction with respect to the intermediate portion 49b of the exhaust pipe 49. The intermediate portion 52b of the exhaust pipe 52 may be disposed offset in the vehicle up-down direction with respect to the intermediate portion 49b of the exhaust pipe 49. The intermediate portion 52b of the exhaust pipe 52 may be disposed offset in both the vehicle up-down direction and the vehicle front-rear direction with respect to the intermediate portion 49b of the exhaust pipe 49.

[0076] In this embodiment, the exhaust pipe 52 is connected to the exhaust port of the internal combustion engine E at a right position in the left-right direction, extends downward from there, and then extends toward the rear in the front-rear direction of the saddle riding vehicle 1b. When the exhaust pipe 52 reaches a middle position in the front-rear direction, it bends so as to extend from the right side to the left side in the left-right direction of the saddle riding vehicle 1b as it heads downstream. In addition, the exhaust pipe 52 extends toward the left side in the left-right direction of the saddle riding vehicle 1b, and when it reaches the position of the downstream portion 52c, it bends so as to extend toward the rear in the front-rear direction of the saddle riding vehicle 1b.

[0077] A catalyst 54 is accommodated inside the intermediate portion 52b of the exhaust pipe 52. In the present embodiment, the catalyst 54 is filled inside a portion of the intermediate portion 52b of the exhaust pipe 52 where the flow path axis L11 extends along the left-right direction of the saddle riding vehicle 1b.

[0078] According to this embodiment, the exhaust pipe 49 of the first exhaust assembly 47 and the exhaust pipe 52 of the second exhaust assembly 48 are arranged so as to intersect as a whole, which improves the degree of freedom in layout related to the catalysts 51, 54. Also, the middle portion 49b of the exhaust pipe 49 in the first exhaust assembly 47 and the middle portion 52b of the exhaust pipe 52 in the second exhaust assembly 48 can be arranged at approximately the same position in the front-rear direction. Therefore, the space of the saddle riding vehicle 1b can be used efficiently.

[0079] As described above, the above embodiment has been described as an example of the technology disclosed in this application. However, the technology in this disclosure is not limited to this, and can be applied to embodiments in which modifications, replacements, additions, omissions, etc. have been made as appropriate. In addition, it is also possible to combine the components described in the above embodiment to create a new embodiment. For example, a part of the configuration or method in one embodiment may be applied to another embodiment, and a part of the configuration in an embodiment can be separated from other configurations in that embodiment and arbitrarily extracted. In addition, the components described in the attached drawings and detailed description include not only components essential for solving the problem, but also components that are not essential for solving the problem in order to exemplify the technology.

[0080] Each of the following sections is a disclosure of a preferred embodiment.

[0081] [Item 1] A vehicle body frame including an engine mounting frame; an internal combustion engine mounted on the engine mounting frame and having an intake port and an exhaust port; a swing arm extending rearward from the engine mounting frame and having a front end supported by a pivot shaft at a rear portion of the engine mounting frame; A rear wheel connected to a rear end of the swing arm; at least one exhaust assembly including an exhaust pipe connected to the exhaust port of the internal combustion engine, a muffler connected to the exhaust pipe, and at least one catalyst housed in an intermediate portion of the exhaust pipe upstream of the muffler; The pivot shaft is disposed higher than a lower portion of the engine mounting frame, A saddle-type vehicle, wherein the catalyst is disposed in front of the rear wheel, behind the internal combustion engine, and below the swing arm.

[0082] [Item 2] The exhaust pipe further includes an upstream portion extending in a front-rear direction of the vehicle upstream of the intermediate portion, and a downstream portion extending in a front-rear direction of the vehicle downstream of the intermediate portion, 2. The saddle riding vehicle according to claim 1, wherein the intermediate portion is disposed in a position closer to a center line extending in a front-rear direction of the vehicle than at least one of the upstream portion and the downstream portion in a left-right direction of the vehicle.

[0083] [Item 3] 3. The saddle riding vehicle according to claim 2, wherein a flow path axis of the portion of the intermediate portion of the exhaust pipe filled with the catalyst is aligned along a left-right direction of the vehicle.

[0084] [Item 4] The upstream portion and the downstream portion are disposed on one side in the left-right direction, The intermediate portion of the exhaust pipe is a first portion connected to the upstream portion and extending from the upstream portion toward the other side in the left-right direction; a second portion curved from the first portion toward the one side in the left-right direction; 4. The saddle riding vehicle according to any one of items 1 to 3, further comprising: a third portion extending from the second portion toward the one side in the left-right direction and connected to the downstream portion.

[0085] [Item 5] 5. The saddle riding vehicle according to item 4, wherein the at least one catalyst includes a first catalyst housed in the first portion of the intermediate portion and a second catalyst housed in the third portion of the intermediate portion.

[0086] [Item 6] 6. The saddle riding vehicle according to item 4 or 5, wherein the first portion and the third portion are disposed at different heights from each other.

[0087] [Item 7] Item 7. The saddle riding vehicle according to item 6, wherein the third portion is positioned higher than the first portion.

[0088] [Item 8] a side cover that covers the upstream portion and the downstream portion from the one side in the left-right direction across the upstream portion and the downstream portion, 8. The saddle riding vehicle according to any one of items 4 to 7, wherein the side cover covers a gap between the first portion and the third portion from the one side in the left-right direction. [Item 9] Further provided with a step on which the rider places his / her foot, 9. The saddle riding vehicle according to item 8, wherein the step is disposed on the one side of the side cover in the left-right direction and is disposed vertically above the side cover in a side view of the vehicle.

[0089] [Item 10] 10. The saddle riding vehicle according to any one of items 1 to 9, wherein a flow path cross-sectional area of ​​a curved corner portion of the exhaust pipe connecting the upstream portion to the intermediate portion increases toward the downstream side in at least a portion along a flow path axis of the corner portion.

[0090] [Item 11] a heat insulating cover that covers the middle portion of the exhaust pipe, 11. The saddle riding vehicle according to any one of items 1 to 10, wherein the heat insulating cover is disposed with a gap from the intermediate portion.

[0091] [Item 12] Further comprising an oxygen sensor disposed downstream of the catalyst; 12. The saddle riding vehicle according to any one of items 1 to 11, wherein the oxygen sensor is attached to the intermediate portion of the exhaust pipe.

[0092] [Item 13] the at least one exhaust assembly includes a first exhaust assembly and a second exhaust assembly disposed on a left side and a right side, respectively, of the vehicle; 13. The saddle riding vehicle according to any one of items 1 to 12, wherein the intermediate portion of the exhaust pipe of the first exhaust assembly and the intermediate portion of the exhaust pipe of the second exhaust assembly face each other in the left-right direction of the vehicle.

[0093] [Item 14] the at least one exhaust assembly includes a first exhaust assembly and a second exhaust assembly; In the exhaust pipe of the first exhaust assembly, the upstream portion is disposed on a left side of the vehicle, the downstream portion is disposed on a right side of the vehicle, and the intermediate portion extends in a left-right direction of the vehicle; 4. The saddle riding vehicle according to item 3, wherein in the exhaust pipe of the second exhaust assembly, the upstream portion is disposed on the right side of the vehicle, the downstream portion is disposed on the left side of the vehicle, and the intermediate portion extends in the left-right direction of the vehicle. [Explanation of symbols]

[0094] 1 Saddle riding vehicle 2 Front wheels 3 Rear wheel 4 Body frame 4a Engine Mounting Frame 10 Swingarm 12 Pivot Axis 16 Intake port 17 Exhaust port 18. Exhaust assembly 20, 39, 43, 49, 52 Exhaust pipe 20d, 39a, 43a, 49a, 52a upstream part 20e, 39b, 43b, 49b, 52b middle part 20f, 39c, 43c, 49c, 52c downstream 20g 1st portion 20h 2nd part 20k 3rd part 20m corner section 21, 40, 44, 50, 53 Muffler 23, 41, 45, 51, 54 Catalyst 23a 1st catalyst 23b 2nd catalyst 24, 42, 46 Heat shield cover 29 Side cover 33 Steps 35 Oxygen Sensor 37 No. 1 Exhaust Assembly 38 Second Exhaust Assembly E. Internal combustion engine G2 Gap L1, L4, L9 center line L2, L3, L5, L6, L7, L8, L10, L11 Channel axis S1, S2, S3 flow passage cross section

Claims

1. A vehicle body frame including an engine mounting frame; an internal combustion engine mounted on the engine mounting frame and having an intake port and an exhaust port; a swing arm extending rearward from the engine mounting frame and having a front end portion pivotally supported by a pivot shaft at a rear portion of the engine mounting frame; A rear wheel connected to a rear end of the swing arm; at least one exhaust assembly including an exhaust pipe connected to the exhaust port of the internal combustion engine, a muffler connected to the exhaust pipe, and at least one catalyst housed in an intermediate portion of the exhaust pipe upstream of the muffler; The pivot shaft is disposed higher than a lower portion of the engine mounting frame, A saddle-type vehicle, wherein the catalyst is disposed in front of the rear wheel, behind the internal combustion engine, and below the swing arm.

2. The exhaust pipe further includes an upstream portion extending in the front-rear direction of the vehicle upstream of the intermediate portion, and a downstream portion extending in the front-rear direction of the vehicle downstream of the intermediate portion, The saddle riding vehicle according to claim 1 , wherein the intermediate portion is disposed in a position closer to a center line extending in a front-rear direction of the vehicle than at least one of the upstream portion and the downstream portion in a left-right direction of the vehicle.

3. 3. The saddle riding vehicle according to claim 2, wherein a flow passage axis of the portion of the intermediate portion of the exhaust pipe filled with the catalyst is aligned along a left-right direction of the vehicle.

4. The upstream portion and the downstream portion are disposed on one side in the left-right direction, The intermediate portion of the exhaust pipe is a first portion connected to the upstream portion and extending from the upstream portion toward the other side in the left-right direction; a second portion curved from the first portion; The saddle riding vehicle according to claim 1 , further comprising: a third portion extending from the second portion toward the one side in the left-right direction and connected to the downstream portion.

5. The saddle riding vehicle according to claim 4 , wherein the at least one catalyst includes a first catalyst housed in the first portion of the intermediate portion and a second catalyst housed in the third portion of the intermediate portion.

6. The saddle riding vehicle according to claim 4 , wherein the first portion and the third portion are disposed at different heights from each other.

7. The saddle riding vehicle according to claim 6 , wherein the third portion is positioned higher than the first portion.

8. a side cover that covers the upstream portion and the downstream portion from the one side in the left-right direction across the upstream portion and the downstream portion, The saddle riding vehicle according to claim 4 , wherein the side cover covers the gap between the first portion and the third portion from the one side in the left-right direction.

9. Further provided with a step on which the rider places his / her foot, 9. The saddle riding vehicle according to claim 8, wherein the step is disposed on the one side of the side cover in the left-right direction and vertically above the side cover in a side view of the vehicle.

10. 4. The saddle riding vehicle according to claim 1, wherein a flow passage cross-sectional area of ​​a curved corner portion of the exhaust pipe connecting the upstream portion to the intermediate portion increases toward the downstream side in at least a portion along a flow passage axis of the corner portion.

11. a heat insulating cover that covers the middle portion of the exhaust pipe, The saddle riding vehicle according to claim 1 , wherein the heat insulating cover is disposed with a gap therebetween with respect to the intermediate portion.

12. Further comprising an oxygen sensor disposed downstream of the catalyst; 4. The saddle riding vehicle according to claim 1, wherein the oxygen sensor is attached to the intermediate portion of the exhaust pipe.

13. the at least one exhaust assembly includes a first exhaust assembly and a second exhaust assembly disposed on a left side and a right side, respectively, of the vehicle; 4. The saddle riding vehicle according to claim 1, wherein the intermediate portion of the exhaust pipe of the first exhaust assembly and the intermediate portion of the exhaust pipe of the second exhaust assembly face each other in the left-right direction of the vehicle.

14. the at least one exhaust assembly includes a first exhaust assembly and a second exhaust assembly; In the exhaust pipe of the first exhaust assembly, the upstream portion is disposed on a left side of the vehicle, the downstream portion is disposed on a right side of the vehicle, and the intermediate portion extends in a left-right direction of the vehicle, 4. The saddle riding vehicle according to claim 3, wherein in the exhaust pipe of the second exhaust assembly, the upstream portion is located on the right side of the vehicle, the downstream portion is located on the left side of the vehicle, and the intermediate portion extends in the left-right direction of the vehicle.

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