Saddle type vehicle

Abstract

A saddled vehicle is provided with a vehicle body frame F, a unit swing engine P swingably supported by the vehicle body frame F via a link member 11, and an exhaust device 50 equipped with an exhaust pipe 51 and a catalyst device 53. An exhaust pipe 51 extends downward from the unit swing engine P, and includes a catalyst device housing exhaust pipe 100, an upstream exhaust pipe 80, and a downstream exhaust pipe 90. An exhaust gas sensor S1 is arranged in the downstream exhaust pipe 90. In a vehicle body side view, an exhaust gas sensor S1 and a catalyst device 53 are located in a region between a first virtual line L1 connecting a rotation center CL of a crankshaft 21 and a link member connection portion 13 connecting a link member 11 to a vehicle body frame F, and a second virtual line L2 connecting the link member connection portion 13 and an exhaust pipe connection portion 24c to which an end of an exhaust pipe 51 is connected. Therefore, the saddle-type vehicle can preheat the exhaust gas sensor earlier, suppress the turbulence of the exhaust gas in the duct, and improve the accuracy of the exhaust gas sensor.

Description

Technical Field

[0001] The present utility model relates to a saddle-riding type vehicle on which a unit swing engine is mounted. Background Art

[0002] As a traditional saddle-riding type vehicle, a vehicle is disclosed in which a unit swing type engine is mounted, a catalyst device is arranged in the middle of an exhaust pipe connected to an internal combustion engine of the unit swing type engine, and an exhaust gas sensor is provided on the upstream side of the catalyst device in the exhaust pipe (see Patent Document 1).

[0003] Prior Art Documents

[0004] Patent Documents

[0005] Patent Document 1: WO 2018 / 025652 Summary of the Utility Model

[0006]

Fundamental Problem to be Solved by the Present Utility Model

[0007] In a traditional saddle-riding type vehicle, an exhaust gas sensor is attached to the exhaust pipe on the upstream side of the catalyst device, and the oxygen concentration of the exhaust gas before passing through the catalyst device is measured. However, by measuring the exhaust gas after passing through the catalyst device, the oxygen concentration in the exhaust gas can be detected more precisely. On the other hand, when the exhaust gas sensor is provided on the exhaust pipe on the downstream side of the catalyst device, the distance from the internal combustion engine increases according to the attachment position of the exhaust gas sensor, and it is difficult to quickly preheat the exhaust gas sensor. In addition, when the exhaust gas sensor is arranged at a position close to the atmospheric opening port of the exhaust pipe, when the pressure in the exhaust pipe becomes negative, the flow of the exhaust gas in the exhaust pipe is disturbed by the external air flowing in from the atmospheric opening port, resulting in a problem that the detection accuracy of the exhaust gas sensor is affected.

[0008]

Means for Solving the Problem

[0009] The present utility model is made in view of the above problems. A saddle-riding type vehicle includes: a body frame, a cylinder portion having a cylinder axis facing forward, a crankcase, a crankshaft, and a unit swing engine swingably supported by the body frame via a connecting rod member; and

[0010] an exhaust device connected to the unit swing engine and including an exhaust pipe and a catalyst device arranged in the middle of the exhaust pipe, wherein

[0011] the exhaust pipe extends downward from the unit swing engine,

[0012] The exhaust pipe includes a catalyst device accommodating exhaust pipe in which a catalyst device is accommodated, an upstream side exhaust pipe connected to the upstream side of the catalyst device accommodating exhaust pipe, and a downstream side exhaust pipe connected to the downstream side of the catalyst device accommodating exhaust pipe.

[0013] An exhaust gas sensor disposed on the downstream side exhaust pipe.

[0014] In a side view of the vehicle body, the exhaust gas sensor and the catalyst device are located in a region between a first virtual line and a second virtual line.

[0015] The first virtual line connects a link member connecting portion to the rotation center of the crankshaft, and the link member connecting portion connects the link member to the vehicle body frame.

[0016] The second virtual line connects an exhaust pipe connecting portion of the unit swing engine to the link member connecting portion, and the exhaust pipe connecting portion is connected to the end of the exhaust pipe.

[0017] According to the above configuration, the exhaust gas sensor is provided on the downstream side exhaust pipe on the downstream side of the catalyst device, so that the oxygen concentration in the exhaust gas can be more accurately detected by measuring the exhaust gas after passing through the catalyst device. In addition, the distance between the exhaust gas sensor and the internal combustion engine is made closer to each other, so that the exhaust gas sensor can be quickly preheated. In addition, the exhaust gas sensor is disposed at a position away from the atmospheric opening port of the exhaust pipe. When the pressure in the exhaust pipe becomes negative, even if the flow of the exhaust gas in the exhaust pipe is disturbed by the outside air flowing in from the atmospheric opening port, the detection accuracy of the exhaust gas sensor will not be affected, and the accuracy of the exhaust gas sensor can be improved.

[0018] In addition, in the present utility model, in a bottom view of the vehicle, at least a part of the downstream side exhaust pipe is located on an extension line of the vehicle body frame, and

[0019] In a front view of the vehicle, at least a part of the exhaust gas sensor overlaps with the vehicle body frame.

[0020] According to the above configuration, in a bottom view of the vehicle, at least a part of the downstream side exhaust pipe is located on an extension line of the vehicle body frame, and in a front view of the vehicle, at least a part of the exhaust gas sensor overlaps with the vehicle body frame. Therefore, the vehicle can be protected from the influence of obstacles (such as flying stones, etc.) on the front side of the vehicle.

[0021] In addition, in the present utility model, in a bottom view of the vehicle, the downstream side exhaust pipe is located at a position more outside in the vehicle width direction than the crankcase,

[0022] The crankcase includes an oil filter that can be removed toward the vehicle side surface direction, and

[0023] In a side view of the vehicle, the exhaust gas sensor is disposed on the downstream side exhaust pipe on the vehicle front side with respect to the oil filter.

[0024] According to the above configuration, when removing the oil filter 66 toward the lateral side of the vehicle, it is possible to operate without the exhaust gas sensor S1 becoming an obstacle.

[0025] In addition, in the present utility model, it further includes a fan that introduces external air into the unit swing engine; and a fan cover that covers the fan from the lateral side of the vehicle, wherein

[0026] In a side view of the vehicle, the downstream exhaust pipe does not overlap with the external air inlet port of the fan cover.

[0027] According to the above configuration, in a side view of the vehicle, the downstream exhaust pipe is arranged at a position where it does not overlap with the external air inlet port of the fan cover. Therefore, the warm air around the downstream exhaust pipe is less likely to be sucked into the power unit, and the cooling efficiency of the fan in the power unit can be improved.

[0028] In addition, in the present utility model, a mesh portion is provided on the outer edge of the fan cover.

[0029] According to the above configuration, the air in the fan cover is discharged by the fan from the mesh portion at the outer edge of the fan cover, so that the downstream exhaust pipe can be cooled by blowing the wind to the downstream exhaust pipe near the fan cover, and the rigidity of the metal constituting the exhaust pipe can be improved.

[0030] In addition, in the present utility model, the exhaust pipe includes a split structure in at least a part thereof.

[0031] According to the above configuration, the exhaust pipe has a split structure, which is easy to form a bent portion with a small curvature and reduces the limitation on the curvature of the pipe.

[0032] In addition, in the present utility model, the exhaust pipe includes a split structure in at least two positions,

[0033] In at least one split structure, the split end edges of the splits are joined together in a butt joint structure to be integrated into a split structure, and

[0034] In another split structure, the split end edge of one split includes a tenon portion that protrudes outward to cooperate with the split end edge of the other split, and one split end edge and the other split end edge are joined together in a tenon joint structure to be integrated into a split structure.

[0035] According to the above configuration, the joint area between the split parts in the split structure joined by the mortise joint structure is larger than the joint area in the split structure joined by the butt joint structure. Therefore, in the case where all two or more split structures only have the split structure with the mortise joint structure, the joint between the semi-bodies is stronger than the joint between the semi-bodies of the split structure with the butt joint structure. However, if the bent portion of the exhaust pipe made of metal is thermally damaged and subjected to a force to return to a linear shape, stress will concentrate on the joint portion between the split parts. A part of the multiple split structures provided in the exhaust pipe has a butt joint structure, so that the rigidity can be reduced and the stress can be dispersed.

[0036]

Technical effects of the utility model

[0037] According to the present utility model, an exhaust gas sensor is provided on the downstream exhaust pipe on the downstream side of the catalyst device, so that the oxygen concentration in the exhaust gas can be detected more accurately by measuring the exhaust gas after passing through the catalyst device. In addition, the distance between the exhaust gas sensor and the internal combustion engine is made closer to each other, so that the exhaust gas sensor can be preheated quickly. In addition, the exhaust gas sensor is arranged at a position far from the atmospheric opening port of the exhaust pipe. When the pressure in the exhaust pipe becomes negative, even if the flow of the exhaust gas in the exhaust pipe is disturbed by the external air flowing in from the atmospheric opening port, the detection accuracy of the exhaust gas sensor will not be affected, and the accuracy of the exhaust gas sensor can be improved. Description of the drawings

[0038] Figure 1 is a left side view of an entire motorcycle applying an intake structure of an internal combustion engine according to an embodiment of the present utility model.

[0039] Figure 2 is Figure 1 an enlarged right side view of a main part of the vehicle.

[0040] Figure 3 is Figure 1 a left side view of a power unit, an intake structure device, and an exhaust device in

[0041] Figure 4 is Figure 2 a plan view of

[0042] Figure 5 is a bottom view of a main part of the motorcycle.

[0043] Figure 6 is a partial cross-sectional view taken along the crankshaft of the internal combustion engine of the power unit.

[0044] Figure 7 is a view showing Figure 2 an enlarged left side view of a main part of the state in which the internal combustion engine in the vehicle is suspended on the body frame.

[0045] Figure 8 is a front view of the main part of the vehicle when viewed from the front side, with the cover removed from this part.

[0046] Figure 9 is a perspective view showing a part of the exhaust pipe.

[0047] Figure 10 is a front view of the exhaust pipe in a state where the first upstream exhaust pipe is indicated by a virtual line.

[0048] Figure 11 is along Figure 9 a cross-sectional view taken along the line XI-XI in

[0049] Figure 12 is along Figure 9 a cross-sectional view taken along the line XII-XII in

[0050] Figure 13 is a view showing another attachment position of the exhaust gas sensor.

[0051] Figure 14 is a view showing yet another attachment position of the exhaust gas sensor. DETAILED DESCRIPTION

[0052] Hereinafter, a saddle-riding type vehicle according to an embodiment of the present invention will be described with reference to Figures 1 - 14 The saddle-riding type vehicle in this embodiment is a scooter 1, and its left side view is shown in Figure 1 .

[0053] Note that in the description of this specification, the front, rear, left, right, up, and down directions correspond to the normal reference, and the straight-ahead direction of the motorcycle 1 according to this embodiment is the front side. In the drawings, FR indicates the front side, RE indicates the rear side, LH indicates the left side, RH indicates the right side, UP indicates the upper side, and DW indicates the lower side.

[0054] As Figure 1 shown, in the motorcycle 1, the front part 1F of the vehicle body and the rear part 1R of the vehicle body are interconnected by a low floor part 1C, and the vehicle body frame F forming the frame of the vehicle body mainly includes a lower pipe 3 and a main pipe 4.

[0055] That is to say, the lower pipe 3 extends downward from the head pipe 2 of the front part 1F of the vehicle body, the lower pipe 3 is horizontally bent at its lower end, and extends backward under the floor part 1C, and at its rear end, a pair of left and right main pipes 4 are connected. In each main pipe 4, an inclined part 4a that extends obliquely upward backward from this connection part is formed, and the upper part of the inclined part 4a is further bent to form a horizontal part 4b that extends horizontally backward.

[0056] Between these pair of main pipes 4, a storage box 5 is supported on the front side, and a fuel tank (not shown) is supported on the rear side. The upper sides of the storage box 5 and the fuel tank are covered with a seat 7. In the front part 1F of the vehicle body, a handlebar 8 is provided on the upper side and pivotally supported by a head pipe 2. A front fork 9 extends downward, and a front wheel 10 is pivotally supported at the lower end of the front fork 9.

[0057] In the front part 1F of the vehicle body, the vertically oriented portions of the head pipe 2 and the down tube 3 are covered from the front and rear sides by a front cowl 1a and leg shields 1b. In the floor part 1c, the front and rear oriented portion of the down tube 3 is covered by a lower cowl 1c. In the rear part 1R of the vehicle body, the left, right, and rear sides of the main pipe 4 are covered by a body cowl 1d.

[0058] In the motorcycle 1, a power unit P located below the main pipe 4 is installed, and the power unit P functions as a unit swing engine. As Figure 3 shown, at the front part of the power unit P, a single-cylinder, four-stroke, air-cooled internal combustion engine 20 is arranged, and a belt-type continuously variable transmission is arranged at the rear part.

[0059] As Figure 7 shown, the power unit P is provided with a pair of left and right engine hangers 22h that project forward from the upper part of the crankcase 22. A link member 11 is provided to project at the rear side of the main pipe 4, and the end of the engine hanger 22h is coupled to the link member 11 via a pivot 12, and the power unit P is swingably coupled to the vehicle body frame F and supported by the vehicle body frame F.

[0060] As Figure 3 shown, by sequentially overlapping from the crankcase 22, the cylinder block 23, the cylinder head 24, and the valve cover 25, the internal combustion engine 20 is provided in a state of projecting forward in a substantially forwardly inclined attitude to a substantially horizontal state where the cylinder axis C faces forward. The crankshaft 21 is oriented in the vehicle width direction and rotatably supported by the crankcase 22.

[0061] As Figure 1 shown, an intake port 24a is formed on the upper surface side of the cylinder head 24, and an intake pipe 31 serving as an intake pipe extends upward from the intake port 24a. An exhaust port 24b is formed on the lower surface side of the cylinder head 24, and an exhaust pipe 51 extends downward from the exhaust port 24b.

[0062] Furthermore, as Figure 3 shown, a spark plug 26 is installed and inserted into the cylinder head 24 to be close to the valve cover 25 located at the center. In addition, as Figure 2 shown, an oxygen concentration sensor 27 is installed and inserted at the position where the exhaust pipe 51 extends.

[0063] Refer to Figure 6, the crankcase 22 includes a left crankcase portion 22L and a right crankcase portion 22R that are divided into left and right. The left crankcase portion 22L and the right crankcase portion 22R are respectively pivotally supported for rotation via main bearings 21b, 21b by a crankshaft 21 oriented in the vehicle width direction.

[0064] An alternator 55 is provided on the right shaft portion of the crankshaft 21, and a centrifugal cooling fan 56 is integrally attached to the outer rotor 55r of the alternator 55.

[0065] A fan cover 57 that covers the right crankcase portion 22R from the right side houses the centrifugal cooling fan 56 inside. Also refer to Figure 2 , a grille 57g that faces the centrifugal cooling fan 56 and serves as an external air inlet port is formed on the fan cover 57. As Figure 2 shown, in the fan cover 57, a mesh portion 57f is formed in a region diagonally rearward and downward around the outer edge 57e of the grille 57g, and the external air that has been introduced from the grille 57g is discharged from the mesh portion 57f to the outside of the fan cover 57 by the rotational force of the centrifugal cooling fan 56.

[0066] As Figure 2 and Figure 6 shown, a shroud 70 surrounds the cylinder block 23 and the cylinder head 24, and the shroud 70 is coupled to the fan cover 57 on the right side.

[0067] As Figure 6 shown, the left crankcase portion 22L extends rearward and also serves as a transmission case portion. A transmission case cover 65 covers this transmission case portion (left crankcase member) 22L from the left side, and a belt-type continuously variable transmission 60 is arranged inside. A drive sprocket 58 is provided adjacent to the main bearing 21b in the left shaft portion of the crankshaft 21, and a drive pulley 61 of the belt-type continuously variable transmission 60 is provided in the left shaft end portion. Power is transmitted to the valve mechanism on the cylinder head 24 side through a cam chain 59, and the cam chain 59 is wound around the drive sprocket 58.

[0068] Refer to Figure 1 and Figure 3 , the reduction gear output shaft of a reduction mechanism 64 provided at the rear of the belt-type continuously variable transmission 60 serves as a rear wheel shaft 28a, and a rear wheel 28 is provided on the rear wheel shaft 28a. A rear buffer (not shown) is interposed between the upper end of the rear portion of the transmission case portion 22L that houses the reduction mechanism 64 and the upper bent portion of the main pipe 4.

[0069] As Figure 3As shown, the driven pulley 63 of the belt-type continuously variable transmission 60 is pivotally supported by the reduction gear input shaft 64a of the reduction mechanism 64. The belt 62 is wound around the drive pulley 61 provided on the crankshaft 21 and the driven pulley 63 provided on the reduction gear input shaft 64a. The power of the internal combustion engine 20 is transmitted to the driven pulley 63 through the belt 62. The rotation of the driven pulley 63 is transmitted to the reduction gear input shaft 64a of the reduction mechanism 64 through a centrifugal clutch (not shown), decelerated by the reduction mechanism 64, and the power is transmitted to the rear wheel 28. As Figure 6 shown, an external intake fan 61F is formed in the pulley half body on the left side of the drive pulley 61.

[0070] As Figure 2 shown, an oil filter 66 is arranged below the crankcase 22 and can be removed toward the vehicle side surface direction, and the oil supplied to various positions of the internal combustion engine 20 is filtered by the oil filter 66.

[0071] Referring to Figure 1 , the intake device 30 is connected to the intake port 24a of the internal combustion engine 20, and the intake device 30 sucks in external air and sends the external air to the internal combustion engine 20. Also referring to Figure 4 , the intake device 30 includes: an air filter device 40 that sucks in and purifies external air; a connecting pipe 36 that is coupled to the air filter device 40; a throttle body 33 that is coupled to the downstream side of the connecting pipe 36; and an intake pipe 31 that is connected to the upstream side of the throttle body 33. A butterfly throttle valve (not shown) is provided inside the throttle body 33, so that these components constitute an intake system. As Figure 4 shown, a fuel injection valve 37 that injects fuel into the intake passage is provided on the intake port 24a and the intake pipe 31.

[0072] The intake device 30 will be further described. As Figure 4 shown, in the air filter device 40 of the intake device 30, an air filter housing 41 (where the unpurified chamber housing 42 on the left and the purified chamber housing 43 on the right are integrated with each other) is separated by a partition portion 45 provided between the unpurified chamber housing 42 and the purified chamber housing 43, and an air filter element 44 is provided therein, so that the air filter element 44 is divided into an unpurified chamber Ca on the unpurified chamber housing 42 side and a purified chamber Cb on the purified chamber housing 43 side.

[0073] As Figure 3As shown, in the unpurified chamber housing 42, the air introduction pipe 47 is arranged with the opening 47a facing forward, and traveling air and the like are sucked into the air introduction pipe 47. The intake air that has been introduced from the opening 47a is purified by passing through the air filter element 44 inside the unpurified chamber Ca, and is sent to the purified chamber Cb. The purified chamber Cb of the air filter device 40 communicates with the throttle body 33 through the connecting pipe 36, and the connecting pipe 36 is made of rubber and can be elastically deformed.

[0074] As Figure 1 shown, the exhaust device 50 is connected to the downstream end of the exhaust port 24b of the cylinder head 24. Referring to Figure 5 , the exhaust pipe connection portion 24c to which the upstream of the exhaust device 50 is connected is provided on the lower surface of the cylinder head 24. The exhaust device 50 includes: an exhaust pipe 51 that is connected to the exhaust port 24b of the internal combustion engine 20 and discharges exhaust gas; a catalyst device 53 that is arranged midway inside the exhaust pipe 51 and purifies the exhaust gas; and a muffler 52 that is connected to the downstream of the exhaust pipe 51, so that these components constitute an exhaust system.

[0075] Reference Figure 2 and Figure 5 , the exhaust pipe 51 communicates with the exhaust port 24b, extends downward from the lower surface of the cylinder head 24, bends obliquely forward to the left, further bends backward, then bends to the right, extends from the left side to the right side under the crankcase 22, further bends backward, and then extends backward, and is connected to the muffler 52 arranged on the right side of the rear wheel 28. The catalyst device 53 is provided midway in the exhaust pipe 51, and the exhaust pipe 51 includes: a catalyst device accommodating exhaust pipe 100 in which the catalyst device 53 is accommodated; an upstream side exhaust pipe 80 that is connected to the upstream side of the catalyst device accommodating exhaust pipe 100; and a downstream side exhaust pipe 90 that is connected to the downstream side of the catalyst device accommodating exhaust pipe 100.

[0076] As Figure 5 shown, in the vehicle bottom view, the downstream side exhaust pipe 90 is arranged at least partially on the extension line of the vehicle body frame F and is located at a position more outside than the crankcase 22 in the vehicle width direction. In addition, as Figure 2 shown, in the side view, the downstream side exhaust pipe 90 is arranged at a position not overlapping with the grille 57g, and the grille 57g serves as an external air introduction port of the fan cover 57 and is configured not to introduce warm air into the periphery of the exhaust pipe 51.

[0077] Exhaust gas discharged from the internal combustion engine 20 passes from the exhaust port 24b through the upstream side exhaust pipe 80, is purified while passing through the catalyst device 53 in the catalyst device housing exhaust pipe 100, then passes through the downstream side exhaust pipe 90 and the muffler 52, and is discharged to the outside air from the atmosphere opening port 52a of the muffler 52. The catalyst device 53 is a honeycomb porous structure having a large number of holes extending along its axial direction, and carries catalysts such as platinum, rhodium, and palladium for decomposing exhaust gas components.

[0078] Figure 9 and Figure 10 shows a main part of the exhaust pipe 51.

[0079] The upstream side exhaust pipe 80 of the exhaust pipe 51 includes: a vertical portion 80a that extends downward from the exhaust pipe connection portion 24c of the cylinder head 24; a lateral side extension portion 80b that extends on one side with respect to the crankcase parting surface on the front side of the catalyst device 53; and a bent portion 80c that bends backward from the downstream end of the lateral side extension portion 80b and is on the other side of the crankcase parting surface, and is folded back in a letter U shape. The downstream end of the bent portion 80c is connected to the catalyst device housing exhaust pipe 100.

[0080] Referring to Figure 9 , the upstream side exhaust pipe 80 includes a first upstream side exhaust pipe 81 connected to the exhaust port 24b, and a second upstream side exhaust pipe 82 connected to the downstream end 81b of the first upstream side exhaust pipe 81. The upstream side exhaust pipe 80 is divided into the first upstream side exhaust pipe 81 and the second upstream side exhaust pipe 82 in the middle of the bent portion 80c of the upstream side exhaust pipe 80.

[0081] The diameter of the upstream end 82a of the second upstream side exhaust pipe 82 is larger than the diameter of the downstream end 81b of the first upstream side exhaust pipe 81. After installing the downstream end 81b of the first upstream side exhaust pipe 81 to the upstream end 82a of the second upstream side exhaust pipe 82, the first upstream side exhaust pipe 81 and the second upstream side exhaust pipe 82 are joined together by being welded in the circumferential direction to be integrated into the upstream side exhaust pipe 80.

[0082] The flange portion 80d to be attached to the exhaust pipe connection portion 24c of the internal combustion engine 20 is fixed and adhered to the upstream end 81a of the first upstream side exhaust pipe 81. As Figure 5 shown, a pair of bolt insertion holes 80e are provided in the flange portion 80d, and the flange portion 80d is attached to the exhaust pipe connection portion 24c of the cylinder head 24 with bolts 69. As Figure 9 shown, the downstream end 82b of the second upstream side exhaust pipe 82 is connected to the upstream end 100a of the catalyst device housing exhaust pipe 100.

[0083] As Figure 10As shown, the second upstream exhaust pipe 82 has a split structure that is roughly divided into two parts along the exhaust gas flow direction, and includes a first split 83 and a second split 84. As Figure 11 shown, when the first split 83 and the second split 84 are joined together, the inner peripheral surface 82d of the second upstream exhaust pipe 82 has a substantially circular shape including the inner peripheral surface 83a of the first split 83 and the inner peripheral surface 84a of the second split 84.

[0084] The split end edge 83b of the first split 83 and the split end edge 83b of the second split 84 respectively serve as mating portions 83c and 84c, and the mating portion 83c of the first split 83 projects outward in a step having a size corresponding to the plate thickness of the mating portion 84c of the second split 84 to form a tenon portion 84d extending along the split end edge 84b.

[0085] The first split 83 and the second split 84 are integrated in such a way that the mating portions 83c and 84c form a so-called tenon joint structure, and are joined together integrally by welding.

[0086] Referring to Figure 5 , the downstream exhaust pipe 90 is connected to the downstream end 100b of the catalyst device accommodating exhaust pipe 100, extends to the right lateral side to extend from the catalyst device accommodating exhaust pipe 100, then extends rearward, and is connected to the muffler 52 on the right lateral side of the rear wheel 28. The downstream exhaust pipe 90 is arranged to be at least partially on the extension line of the vehicle body frame F.

[0087] Also referring to Figure 9 , the downstream exhaust pipe 90 includes: a first downstream exhaust pipe 91, whose upstream end 91a is connected to the downstream end 100b of the catalyst device accommodating exhaust pipe 100; and a second downstream exhaust pipe 92, whose upstream end 92a is connected to the downstream end 91b of the first downstream exhaust pipe 91. The downstream exhaust pipe 90 is a bent part and is divided into the first downstream exhaust pipe 91 and the second downstream exhaust pipe 92.

[0088] The diameter of the downstream end b of the first downstream exhaust pipe 91 is larger than the diameter of the upstream end 92a of the second downstream exhaust pipe 92. After installing the upstream end 92a of the second downstream exhaust pipe 92 to the downstream end 91b of the first downstream exhaust pipe 91, the first downstream exhaust pipe 91 and the second downstream exhaust pipe 92 are welded in the circumferential direction and joined together to be integrated into the downstream exhaust pipe 90.

[0089] As Figure 10 shown, the first downstream exhaust pipe 91 has a split structure that is roughly divided into two parts along the exhaust gas flow direction, and includes a first split 93 and a second split 94. As Figure 12As shown, when the first and second split bodies 93 and 94 are joined together, the inner peripheral surface 91 d of the first downstream exhaust pipe 91 has a substantially circular shape including the inner peripheral surface 93 a of the first split body 93 and the inner peripheral surface 94 a of the second split body 94 .

[0090] The split end edge 93b of the first split body 93 and the split end edge 93b of the second split body 94 have a so-called butt joint structure, in which they are folded outward and overlap each other. The first split body 93 and the second split body 94 are integrated in a manner that the split end edges 93b and 94b are formed to have a butt joint structure, in which the overlapping ends are integrally joined together by welding.

[0091] In the present embodiment, there are two split structures, but any number of splits may be used as long as there are two or more splits in the exhaust pipe 51. In addition, it is sufficient to adopt a split structure joined by a butt joint structure in at least one of the plurality of split structures. Another split structure may be a split structure joined by a mortise and tenon joint structure.

[0092] like Figure 2 As shown, the exhaust pipe 90 on the downstream side of the exhaust pipe 51 is provided with an exhaust gas sensor S1 for detecting the oxygen concentration and the like in the exhaust gas after passing through the catalyst device 53 for purifying the exhaust gas. The exhaust gas sensor S1 is a LAF sensor or an O2 sensor.

[0093] The exhaust gas sensor S1 is attached so as to be inserted into the exhaust pipe 51 from the upper surface of the second downstream side exhaust pipe 92. Figure 7 As shown, the exhaust gas sensor S1 is provided in a predetermined area located on the lower right lateral side of the internal combustion engine 20 in the downstream side exhaust pipe 90 in the vehicle side view.

[0094] The exhaust gas sensor S1 and the catalyst device 53 are arranged in the Figure 7 In the area surrounded by the first virtual line L1 and the second virtual line L2 in the vehicle. In the vehicle side view, the first virtual line L1 is a virtual line connecting the connecting rod member coupling portion 13, which is a position where the connecting rod member 11 is joined to the main pipe 4 of the vehicle body frame F, and the rotation center CL of the crankshaft 21 of the internal combustion engine 20. The second virtual line L2 is a virtual line connecting the connecting rod member coupling portion 13 and the exhaust pipe connecting portion 24c, where the exhaust pipe 51 is connected to the internal combustion engine 20.

[0095] The exhaust gas sensor S1 and the catalyst device 53 are arranged in the Figure 7In the region surrounded by the first virtual line L1 and the second virtual line L2 in [description], the exhaust gas sensor S1 and the catalyst device can be arranged in a compact manner. In addition, the exhaust gas sensor S1 and the catalyst device 53 are arranged at a position close to the exhaust port 24b of the internal combustion engine 20, so that the exhaust gas sensor S1 and the catalyst device 53 can be quickly preheated.

[0096] In addition, as Figure 2 shown, in the side view of the vehicle, the exhaust gas sensor S1 is disposed on the downstream exhaust pipe 90 on the front side of the vehicle with respect to the oil filter 66. Therefore, when the oil filter 66 is removed toward the lateral side of the vehicle, the operation can be performed without the exhaust gas sensor S1 becoming an obstacle.

[0097] In addition, as Figure 8 shown, the exhaust gas sensor S1 is arranged at a position that at least partially overlaps with the body frame F, thereby preventing damage caused by obstacles (such as flying stones, etc.) from the front side.

[0098] In the motorcycle 1 of the present embodiment, the exhaust gas sensor S1 is attached to the second downstream exhaust pipe 92 from above. However, it is sufficient to attach the exhaust gas sensor S1 to a position that satisfies the above conditions. For example, the exhaust gas sensor S1 can be attached to the first downstream exhaust pipe 91 from above as Figure 13 shown, or can be attached to the rear side of the first downstream exhaust pipe 91 as Figure 14 shown.

[0099] The motorcycle 1 of the saddle-riding type vehicle according to an embodiment of the present utility model is configured as described above, and achieves the following effects.

[0100] The motorcycle 1 includes: a body frame F, a cylinder part 23 having a forward-facing cylinder axis C, a crankcase 22, a crankshaft 21, and a power unit P swingably supported by the body frame F via a connecting rod member 11; and an exhaust device 50 connected to the power unit P and including an exhaust pipe 51 and a catalyst device 53 disposed midway in the exhaust pipe 51. The exhaust pipe 51 extends downward from the power unit P and includes a catalyst device accommodating exhaust pipe 100 in which the catalyst device 53 is accommodated, an upstream exhaust pipe 80 connected to the upstream side of the catalyst device accommodating exhaust pipe 100, and a downstream exhaust pipe 90 connected to the downstream side of the catalyst device accommodating exhaust pipe 100. An exhaust gas sensor S1 is disposed on the downstream exhaust pipe 90. In a side view of the vehicle body, the exhaust gas sensor S1 and the catalyst device 53 are located in a region between a first virtual line L1 and a second virtual line L2. The first virtual line L1 connects a connecting rod member joint portion 13 to the rotation center CL of the crankshaft 21, and the connecting rod member joint portion 13 connects the connecting rod member 11 to the body frame F. The second virtual line L2 connects an exhaust pipe connection portion 24c of the power unit P to the connecting rod member joint portion 13, and the exhaust pipe connection portion 24c is connected to an end of the exhaust pipe 51.

[0101] According to such a configuration, the exhaust gas sensor S1 is provided on the downstream exhaust pipe 90 on the downstream side of the catalyst device 53, so that the oxygen concentration in the exhaust gas can be more accurately detected by measuring the exhaust gas after passing through the catalyst device 53. In addition, the distance between the exhaust gas sensor S1 and the internal combustion engine 20 is made close to each other, so that the exhaust gas sensor S1 can be quickly preheated. In addition, the exhaust gas sensor S1 is disposed at a position away from the atmospheric opening port 52a of the exhaust pipe 51. When the pressure in the exhaust pipe 51 becomes negative, even if the flow of the exhaust gas in the exhaust pipe 51 is disturbed by the outside air flowing in from the atmospheric opening port 52a, the detection accuracy of the exhaust gas sensor S1 is not affected, and the accuracy of the exhaust gas sensor S1 can be improved.

[0102] In addition, in a bottom view of the vehicle, at least a part of the downstream exhaust pipe 90 is located on an extension line of the body frame F, and in a front view of the vehicle, at least a part of the exhaust gas sensor S1 overlaps with the body frame F. Therefore, the vehicle can be protected from the influence of obstacles (such as flying stones, etc.) from the front side of the vehicle.

[0103] In addition, in a bottom view of the vehicle, the downstream exhaust pipe 90 is located at a position more outside in the vehicle width direction than the crankcase 22. The crankcase 22 includes an oil filter 66 that can be removed toward the vehicle side surface direction, and in a side view of the vehicle, the exhaust gas sensor S1 is disposed on the downstream exhaust pipe 90 on the front side of the vehicle with respect to the oil filter 66. Therefore, when the oil filter 66 is removed toward the vehicle lateral side, the work can be carried out without the exhaust gas sensor S1 becoming an obstacle.

[0104] In addition, it further includes a centrifugal cooling fan 56 for introducing external air into the power unit P and a fan cover 57 that covers the centrifugal cooling fan 56 from the lateral side of the vehicle. In a side view of the vehicle, the downstream exhaust pipe 90 does not overlap with the grille 57g that serves as an external air inlet port of the fan cover 57. Therefore, the warm air around the downstream exhaust pipe 90 is less likely to be sucked into the power unit P, and the cooling efficiency of the centrifugal cooling fan 56 in the power unit P can be improved.

[0105] In addition, a mesh portion 57f is provided at the outer edge 57e of the fan cover 57, and the air in the fan cover 57 is discharged from the mesh portion 57f by the rotation of the centrifugal cooling fan 56. Therefore, the downstream exhaust pipe 90 can be cooled by blowing air onto the downstream exhaust pipe 90 near the fan cover 57, and the rigidity of the metal constituting the exhaust pipe 51 can be improved.

[0106] In addition, the exhaust pipe 51 includes a second upstream exhaust pipe 82 and a first downstream exhaust pipe 91, each of which has a split structure in at least a part thereof. Therefore, it is easy to form a bent portion with a small curvature, and the limitation on the pipe curvature is reduced.

[0107] In addition, the exhaust pipe 51 includes split structures 82 and 91 at at least two positions, at least one of which is a split structure like the first downstream exhaust pipe 91, in which the split end edges 93b and 94b of the first split 93 and the second split 94 are joined together in a butt joint structure to be integrated into a split structure, and the other is a split structure like the second upstream exhaust pipe 82, in which the split end edge 83b of the first split 83 includes a tenon portion 84d that protrudes outward to cooperate with the split end edge 84b of the second split 84, and the split end edge 83b and the split end edge 84b are joined together in a tenon joint structure to be integrated into a split structure.

[0108] The joint area between the splits in the split structure joined by the tenon joint structure is larger than the joint area in the split structure joined by the butt joint structure. Therefore, in the case where all two or more split structures only have the split structure of the tenon joint structure, the joint between the halves is stronger than the joint between the halves of the split structure of the butt joint structure. However, if the bent portion of the exhaust pipe made of metal is thermally damaged and subjected to a force to return to a linear shape, stress will concentrate on the joint portion between the splits. A part of the multiple split structures provided in the exhaust pipe has a butt joint structure, so that the rigidity can be reduced and the stress can be dispersed.

[0109] As described above, the intake structure of an internal combustion engine according to an embodiment of the present invention has been described. However, various aspects of the present invention are not limited to the above embodiments, and also include implementation manners of various aspects within the scope of the gist of the present invention.

[0110]

List of Reference Marks

[0111] P Power unit

[0112] C Cylinder axis

[0113] CL Crankshaft rotation center

[0114] F Body frame

[0115] S1 Exhaust gas sensor

[0116] 1 Motorcycle

[0117] L1 First virtual line

[0118] L2 Second virtual line

[0119] 11 Connecting rod member

[0120] 13 Connecting rod member connection part

[0121] 20 Internal combustion engine

[0122] 21 Crankshaft

[0123] 22 Crankcase

[0124] 23 Cylinder block

[0125] 24 Cylinder head

[0126] 24c Exhaust pipe connection part

[0127] 50 Exhaust device

[0128] 51 Exhaust pipe

[0129] 53 Catalyst device

[0130] 56 Fan

[0131] 57 Fan cover

[0132] 57e Outer edge

[0133] 57f Mesh part

[0134] 57g Grille

[0135] 80 Upstream exhaust pipe

[0136] 82 Second upstream exhaust pipe

[0137] 83 Split body

[0138] 83b Split body end edge

[0139] 84 Split body

[0140] 84b Split body end edge

[0141] 84d Tenon joint part

[0142] 90 Downstream exhaust pipe

[0143] 91 First downstream exhaust pipe

[0144] 93 Split body

[0145] 93b Split body end edge

[0146] 94 Split body

[0147] 94b Split body end edge

[0148] 100 Catalyst device accommodation exhaust pipe.

Claims

1. A saddle-riding type vehicle, characterized in that, Comprising: a body frame (F), a cylinder part (23) arranged with a forward-facing cylinder axis (C), a crankcase (22), a crankshaft (21), and a unit swing engine (P) swingably supported by the body frame (F) via a connecting rod member (11); and an exhaust device (50) connected to the unit swing engine (P) and including an exhaust pipe (51) and a catalyst device (53) arranged midway in the exhaust pipe (51), wherein the exhaust pipe (51) extends downward from the unit swing engine (P), the exhaust pipe (51) includes a catalyst device accommodating exhaust pipe (100) in which the catalyst device (53) is accommodated, an upstream side exhaust pipe (80) connected to the upstream side of the catalyst device accommodating exhaust pipe (100), and a downstream side exhaust pipe (90) connected to the downstream side of the catalyst device accommodating exhaust pipe (100), an exhaust gas sensor (S1) is arranged on the downstream side exhaust pipe (90), in a side view of the vehicle body, the exhaust gas sensor (S1) and the catalyst device (53) are located in a region between a first virtual line (L1) and a second virtual line (L2), the first virtual line (L1) connects a connecting rod member joint part (13) to the rotation center (CL) of the crankshaft (21), and the connecting rod member joint part (13) joints the connecting rod member (11) to the body frame (F), the second virtual line (L2) connects an exhaust pipe connection part (24c) of the unit swing engine (P) to the connecting rod member joint part (13), and the exhaust pipe connection part (24c) is connected to an end of the exhaust pipe (51), the exhaust pipe (51) includes a split structure (82, 91) in at least one part, the exhaust pipe (51) includes a split structure (82, 91) in at least two positions, in at least one split structure (91), split end edges (93b, 94b) of splits (93, 94) are joined together in a butt joint structure to be integrated into the split structure (91), and in another split structure (82), a split end edge (83b) of one split (83) includes a tenon joint part (84d) protruding outward to cooperate with a split end edge (84b) of another split (84), and one split end edge (83b) and another split end edge (84b) are joined together in a tenon joint structure to be integrated into the split structure (82).

2. The saddle-riding type vehicle according to claim 1, characterized in that, in a bottom view of the vehicle, the downstream side exhaust pipe (90) is at least partially located on an extension line of the body frame (F), and in a front view of the vehicle, the exhaust gas sensor (S1) at least partially overlaps with the body frame (F).

3. The saddle-riding type vehicle according to claim 1 or 2, characterized in that, in a bottom view of the vehicle, the downstream side exhaust pipe (90) is located at a position outside the crankcase (22) in the vehicle width direction, The crankcase (22) includes an oil filter (66) to be removed in the direction of the vehicle side surface, and In a vehicle side view, the exhaust gas sensor (S1) is arranged on a downstream side exhaust pipe (90) on the front side of the vehicle with respect to the oil filter (66).

4. The saddle-riding type vehicle according to any one of the preceding claims 1 to 3, characterized in that, It further includes a fan (56) that introduces external air into the unit swing engine (P); and a fan shroud (57) that covers the fan (56) from the vehicle lateral side, wherein In a vehicle side view, the downstream side exhaust pipe (90) does not overlap with an external air introduction port (57g) of the fan shroud (57).

5. The straddle-type vehicle according to claim 4, wherein A net portion (57f) is provided on an outer edge (57e) of the fan shroud (57).

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