JP6839326B2 - Exhaust structure of saddle-riding vehicle - Google Patents

Description

The present invention relates to an exhaust structure of a saddle-mounted vehicle.

Conventionally, in a lower link type scooter type vehicle in which the lower part of the power unit is swingably supported by a vehicle body frame via a link, an exhaust structure in which a catalyst is provided in the middle of an exhaust pipe connected to the power unit is disclosed (for example). , Patent Document 1).

Japanese Unexamined Patent Publication No. 2013-36422

In the prior art, the exhaust pipe extends in the front-rear direction on one side in the vehicle width direction, and a catalyst having a large outer diameter is provided in the middle of the exhaust pipe, so that the catalyst protrudes to one side and the bank angle of the vehicle. It becomes difficult to secure. Therefore, in order to increase the bank angle of the vehicle, it is conceivable to arrange the catalyst so as to extend in the vehicle width direction in the vicinity of the connection portion between the power unit and the exhaust pipe. There is a problem that it becomes difficult to activate.
An object of the present invention is to provide an exhaust structure for a saddle-riding vehicle capable of easily activating a catalyst while securing a bank angle of the vehicle.

The exhaust structure of the saddle-riding vehicle is provided by a vehicle body frame (11), a seat (17) supported by the vehicle body frame (11), and a lower portion of the vehicle body frame (11) in front of the seat (17). The footrest portion (63), the fuel tank (56) arranged below the footrest portion (63), and the footrest portion (63) and the fuel tank (56) arranged behind the footrest portion (63). A power unit (14) swingably supported by a vehicle body frame (11) via a link member (38), an exhaust pipe (51) connected to the power unit (14), and the exhaust pipe (51). In the exhaust structure of a saddle-mounted vehicle including a silencer (52) to be connected and a catalytic converter (54) provided in the middle of the exhaust pipe (51) so as to extend in the vehicle width direction, the exhaust pipe ( 51) is an upstream pipe (87) extending downward from the lower surface of the cylinder head (46) and curved to one side in the vehicle width direction to be connected to the other end of the catalytic converter (54). The catalytic converter (54) is provided with a downstream pipe (88) extending unilaterally in the vehicle width direction and curved rearward from one end of the catalytic converter (54), and the longitudinal direction of the catalytic converter (54) is in the vehicle width direction. The catalytic converter (54) is arranged behind the fuel tank (56) so that the entire catalytic converter (54) overlaps the fuel tank (56) when viewed from the front of the vehicle. When the vehicle body vertical center line (111) extending in the vertical direction is drawn through the center of the vehicle body in the vehicle width direction, the catalytic converter (54) is one in the vehicle width direction with respect to the vehicle body vertical center line (111). The oxygen sensor (108) is arranged laterally, and the oxygen sensor (108) is arranged in the middle of the upstream pipe (87) , and the oxygen sensor (108) is arranged so that the longitudinal direction thereof faces the vehicle width direction and is viewed from the bottom. , The catalytic converter (54) is arranged above the catalytic converter (54) so as to overlap at least a part of the catalytic converter (54) , the catalytic converter (54) has a larger cross-sectional shape than the exhaust pipe (51), and the catalyst. cross-sectional shape of the converter (54) has a length axis and characterized that you have been a horizontal or substantially horizontal elliptical or oval.
In the above configuration, the catalytic converter (54) is extended to the front and rear of the vehicle body through the center of the vehicle body in the vehicle width direction (110) and one side surface (56c) of the fuel tank (56) in the vehicle width direction. It may be arranged in the vehicle width direction between and.

Further, in the above configuration, an undercover (64, 124) is arranged below the catalytic converter (54) between the catalytic converter (54) and the fuel tank (56), and the undercover (64) is arranged. , 124) are arranged so as to overlap the catalytic converter (54) in terms of bottom view, and the rear surface (64b) of the rear end portion (64a) of the undercover (64) allows the catalytic converter (54) to be viewed from the front. It is formed so as to wrap around downward and covers the catalytic converter (54), and the link member (38) is arranged above the cylinder portion (44) of the engine (41) constituting the power unit (14). It may have been done.
The exhaust structure of the saddle-riding vehicle is provided by a vehicle body frame (11), a seat (17) supported by the vehicle body frame (11), and a lower portion of the vehicle body frame (11) in front of the seat (17). The footrest portion (63), the fuel tank (56) arranged below the footrest portion (63), and the footrest portion (63) and the fuel tank (56) arranged behind the footrest portion (63). A power unit (14) swingably supported by a vehicle body frame (11) via a link member (38), an exhaust pipe (51) connected to the power unit (14), and the exhaust pipe (51). In the exhaust structure of a saddle-mounted vehicle including a silencer (52) to be connected and a catalytic converter (54) provided in the exhaust pipe (51), the catalytic converter (54) has a longitudinal direction of the vehicle. The catalytic converter (54) is rearward of the fuel tank (56) so that the catalytic converter (54) is arranged so as to face the width direction and the entire catalytic converter (54) overlaps the fuel tank (56) when viewed from the front of the vehicle. When the vehicle body vertical center line (111) that is arranged and extends in the vertical direction through the center of the vehicle body width direction is drawn, the catalytic converter (54) is in the vehicle width direction with respect to the vehicle body vertical center line (111). An undercover (64, 124) is arranged between the catalytic converter (54) and the fuel tank (56) below the catalytic converter (54) so as to be arranged on one side of the undercover. (64, 124) are arranged so as to overlap the catalytic converter (54) in terms of bottom view, and the rear surface (64b) of the rear end portion (64a) of the undercover (64) has the catalytic converter (54). It is formed so as to wrap around from the front to the bottom and covers the catalytic converter (54), and the link member (38) is above the cylinder portion (44) of the engine (41) constituting the power unit (14). It is characterized by being arranged in.
Further, in the above configuration, the cross member (81) is arranged between the catalytic converter (54) and the fuel tank (56), and the undercover (64, 124) is from the cross member (81) side. It may extend backward.

Also, in the above configuration, the exhaust pipe (51) is fastened by a fastening member (91) wherein the power unit (14), in the under cover (64,124), the tool (97 to turn the fastening member (91) (64k, 124k) is formed, and the notch (64k, 124k) is formed so as to overlap the fastening member (91) and not to overlap with the catalytic converter (54) in bottom view. You may.

The exhaust structure of the saddle-riding vehicle is arranged below the vehicle body frame, the seat supported by the vehicle body frame, the footrest portion provided at the lower part of the vehicle body frame in front of the seat, and the footrest portion. A fuel tank, a power unit arranged behind the footrest and the fuel tank and swingably supported by the vehicle body frame via a link member, an exhaust pipe connected to the power unit, and the exhaust system. In the exhaust structure of a saddle-mounted vehicle including a silencer connected to a pipe and a catalytic converter provided in the exhaust pipe, the catalytic converter is arranged so that its longitudinal direction is directed toward the vehicle width direction. The catalyst converter is arranged behind the fuel tank so that the entire catalyst converter overlaps with the fuel tank when viewed from the front of the vehicle, and draws a vehicle body vertical center line extending in the vertical direction through the center of the vehicle body in the vehicle width direction. At that time, the catalytic converter is arranged on one side in the vehicle width direction with respect to the vehicle body vertical center line. According to this configuration, since the catalytic converter does not protrude outward from the fuel tank in the vehicle width direction, it is possible to easily secure the bank angle of the vehicle. Further, since the fuel tank is located in front of the catalytic converter, it is possible to make it difficult for the running wind to hit the catalytic converter, and it is possible to easily activate the catalytic converter.
In the above configuration, even if the catalytic converter is arranged in the vehicle width direction between the vehicle body front-rear center line extending in the vehicle body front-rear direction through the center of the vehicle body width direction and one side surface of the fuel tank in the vehicle width direction good. According to this configuration, the amount of protrusion of the exhaust pipe toward the vehicle width direction can be reduced, and the bank angle of the vehicle can be secured. Further, the catalytic converter can be compactly arranged in the space, and further, the portion of the space where the catalytic converter is not arranged can be utilized as a space for arranging other parts.

Further, in the above configuration, an undercover is arranged below the catalytic converter between the catalytic converter and the fuel tank, and the undercover is arranged so as to overlap the catalytic converter in a bottom view. The rear surface of the rear end portion of the undercover is formed so as to wrap around the catalytic converter from the front to the lower side to cover the catalytic converter, and the link member is above the cylinder portion of the engine constituting the power unit. It may be arranged. According to this configuration, the undercover can protect the catalytic converter from external factors, and at the same time, the appearance can be improved by covering the front of the catalytic converter.
Further, in the above configuration, a cross member may be arranged between the catalytic converter and the fuel tank, and the undercover may extend rearward from the cross member side. According to this configuration, since the catalytic converter is arranged in the space in front of the crankcase below the cylinder portion, the space can be effectively used and interference with other members can be prevented.

Further, in the above configuration, an oxygen sensor is arranged in the middle of the exhaust pipe, and the oxygen sensor is arranged with its longitudinal direction facing the vehicle width direction, and at least a part of the catalytic converter in bottom view. It may be arranged above the catalytic converter so as to overlap. According to this configuration, the oxygen sensor can be protected from below by a catalytic converter.
Further, in the above configuration, the exhaust pipe is fastened to the power unit by a fastening member, and a notch through which a tool for turning the fastening member is passed is formed in the undercover. It may be formed so as to overlap with the catalytic converter and not to overlap with the catalytic converter. According to this configuration, by providing a notch, the undercover can be brought closer to the catalytic converter to easily protect the catalytic converter, and the exhaust device can be easily attached and detached when the exhaust device is maintained or replaced. Workability can be improved.

FIG. 1 is a right side view (first embodiment) of a motorcycle having an exhaust structure according to the present invention. FIG. 2 is a bottom view showing a motorcycle. FIG. 3 is a perspective view showing an exhaust pipe, a catalytic converter, and its surroundings. FIG. 4 is an enlarged view of a main part of FIG. FIG. 5 is a right side view showing a power unit, a fuel tank, and their surroundings of a motorcycle. FIG. 6 is an enlarged view of a main part of FIG. FIG. 7 is a sectional view taken along line VII-VII of FIG. FIG. 8 is a right side view (second embodiment) of a main part of a motorcycle having an exhaust structure according to the present invention. FIG. 9 is a bottom view showing the catalytic converter, the undercover, and the surroundings thereof.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the explanation, the directions such as front / rear / left / right and up / down are the same as the directions with respect to the vehicle body unless otherwise specified. Further, the reference numeral FR shown in each figure indicates the front of the vehicle body, the reference numeral UP indicates the upper part of the vehicle body, and the reference numeral LH indicates the left side of the vehicle body.
<First Embodiment>
FIG. 1 is a right side view (first embodiment) of a motorcycle 10 having an exhaust structure according to the present invention.
The motorcycle 10 has a front wheel 13 that is steerably supported at the front end of the vehicle body frame 11 via a front fork 12, and a rear wheel 16 that is oscillating up and down via a power unit 14 at the bottom of the body frame 11. And a seat 17 on which the driver sits.
The vehicle body frame 11 is composed of a front frame 21 arranged on the front side, a rear frame 22 attached to the rear end portion of the front frame 21, and a seat frame 23 attached to the upper part of the rear frame 22.
The seat frame 23 supports the seat 17 on its upper portion.

The front frame 21 includes a head pipe 25 that rotatably supports the front fork 12, a down frame 26 that extends diagonally downward and rearward from the head pipe 25, and a pair of left and right lower frames 27 that extend rearward from the down frame 26. ..
The rear frame 22 is fixed to a pair of left and right rear pipes 31, front cross pipes 32 and rear cross pipes 33 provided on the left and right rear pipes 31 so as to extend in the vehicle width direction, and front ends of the left and right rear pipes 31, respectively. It is provided with a support frame 34.
The support frame 34 is a member to which the rear ends of the left and right lower frames 27 of the front frame 21 are connected.

A bar handle 36 is attached to the upper end of the front fork 12, and a front wheel 13 is supported at the lower end via an axle 37.
The power unit 14 includes an engine 41 that is swingably supported by a rear frame 22 via a link member 38, and a continuously variable transmission 42 that is integrally provided with the engine 41 so as to extend rearward.
The engine 41 includes a crankcase 43 and a cylinder portion 44 extending forward and upward from the crankcase 43. The cylinder portion 44 includes a cylinder head 46, and an exhaust device 47 is connected to the lower portion of the cylinder head 46. The exhaust device 47 includes an exhaust pipe 51 connected to the cylinder head 46, a catalytic converter 54 provided in the middle of the exhaust pipe 51, and a silencer 52 connected to the rear end of the exhaust pipe 51. ..
The catalyst converter 54 is provided in the middle of the exhaust pipe 51 so as to extend in the vehicle width direction, and purifies the exhaust gas by the catalyst. Fuel tanks 56 (see FIG. 5) are attached to the left and right lower frames 27 in front of the exhaust pipe 51.
The rear wheel 16 of the continuously variable transmission 42 is supported at its rear end via an axle 57.

A part of the vehicle body frame 11 described above is covered with the vehicle body cover 60. The vehicle body cover 60 includes a front cover 61, a front inner cover 62, a floor step 63, an undercover 64, and a rear cover 66.
The front cover 61 covers the upper part of the front fork 12 and the front of the head pipe 25. The front inner cover 62 is attached to the rear portion of the front cover 61 and covers the upper part of the front fork 12, the head pipe 25, and the upper part of the down frame 26 from the rear.
The front cover 61 and the front inner cover 62 form a front case 68, and a battery, a fuse box, and the like are housed in the front case 68.

The floor step 63 is attached to the upper part of the left and right lower frames 27, covers the lower part of the down frame 26 from the rear, and functions as a footrest portion for the driver. The undercover 64 is attached to the left and right lower frames 27, covers the front portion of the exhaust pipe 51 (the portion where the catalytic converter 54 is located) from the front and the bottom, and covers the fuel tank 56 from the bottom. The rear cover 66 is attached to the rear frame 22 and covers the power unit 14 and the rear wheels 16 from above.
The front wheel 13 is covered with the front fender 71 from above. The rear wheel 16 is covered with the rear fender 72 from above.
A main stand 74 is arranged below the crankcase 43. The silencer 52 is covered with a heat shield plate 76 above and to the side of the upper portion.

FIG. 2 is a bottom view showing the motorcycle 10.
The left and right lower frames 27, 27 of the front frame 21 extend from the down frame 26 to the left and right side, curve backward, and further extend in the front-rear direction.
The rear portions of the left and right lower frames 27, 27 are integrally connected by a cross member 81, and undercovers 64 are attached to the left and right lower frames 27, 27 so as to straddle the cross members 81 in the front-rear direction.
The exhaust pipe 51 extends from the cylinder portion 44 in the vehicle width direction (specifically, to the right), further extends rearward, and is connected to the silencer 52. The front and lower portions of the exhaust pipe 51 extending in the vehicle width direction are covered with the rear end portion 64a of the undercover 64. A catalytic converter 54 is provided in a portion of the exhaust pipe 51 extending in the vehicle width direction. The rear end portion 64a of the undercover 64 is arranged in front of and below the catalytic converter 54.

A main stand 74 is fixed to the lower surface of the crankcase 43 of the engine 41 via a lower plate 93. Further, a rear wheel 16 is arranged behind the engine 41. A continuously variable transmission 42 is arranged on one side (specifically, the left side) of the rear wheel 16, and a silencer 52 is arranged on the other side (specifically, the right side) of the rear wheel 16.
The fuel tank 56 includes a tank body (a portion shown by a broken line) 56h for storing fuel, and flanges 56f (see FIG. 5) protruding from the tank body 56h on both sides. The flange 56f is fixed to the left and right lower frames 27, 27, and the tank body 56h is arranged between the left and right lower frames 27, 27.

FIG. 3 is a perspective view showing the exhaust pipe 51, the catalytic converter 54, and the surroundings thereof, and is a view seen from diagonally below on the left side of the vehicle body.
The cylinder portion 44 of the engine 41 includes a cylinder block 83 provided so as to project forward from the crankcase 43, and a cylinder head 46 attached to the front end portion of the cylinder block 83 via a head gasket (not shown). Be prepared.
The exhaust pipe 51 includes a front exhaust pipe 85 connected to the lower surface of the cylinder head 46 and a rear exhaust pipe 86 connected to the rear end of the catalytic converter 54.

The front exhaust pipe 85 includes an upstream pipe 87 and a downstream pipe 88. The upstream pipe 87 extends downward from the cylinder head 46 and curves to extend laterally (specifically, to the right). The downstream pipe 88 extends laterally (specifically, to the right) from the end of the catalytic converter 54 connected to the end of the upstream pipe 87, and is curved and extends rearward.
As described above, the catalytic converter 54 is provided between the upstream pipe 87 and the downstream pipe 88, that is, in the middle of the front exhaust pipe 85. The catalytic converter 54 is arranged so that its ends on both sides are connected to the upstream pipe 87 and the downstream pipe 88, respectively, and extend in the vehicle width direction.

The upstream pipe 87 is provided with a flange 87a fastened to connect to the cylinder head 46 at the upstream end, and the diameter is gradually increased from the flange 87a toward the downstream side. The diameter of the downstream pipe 88 gradually decreases toward the downstream, and the downstream end is connected to the rear exhaust pipe 86. That is, the ends of the upstream pipe 87 and the downstream pipe 88 connected to the catalyst converter 54 have the largest diameter, which is substantially the same as the outer diameter of the catalyst converter 54. A pair of stud bolts (not shown) protruding from the mounting surface of the cylinder head 46 are penetrated through the flange 87a when the flange 87a is applied to the mounting surface of the cylinder head 46, and a nut 91 is screwed to the tip of each stud bolt. .. As a result, the exhaust device 47 is fastened to the cylinder head 46.

A lower plate 93 is attached to the lower part of the crankcase 43, and a main stand 74 (see FIG. 2) is attached to the lower plate 93.
The cross member 81 of the front frame 21 is integrally composed of left and right side walls 81a and 81a extending downward from the left and right lower frames 27 and a bottom wall 81b connecting the left and right side walls 81a and 81a.
The rear end portion 64a of the undercover 64 extends in the front-rear direction inside the cross member 81, and further extends from the front to the bottom of the front exhaust pipe 85. The rear end portion 64a is formed so that a notch 64k for passing a tool 97 for turning one nut 91 extends in the front-rear direction and the rear end portion 64a is opened.

The notch 64k divides the rear end portion 64a into a left end portion 64m located below the upstream pipe 87 and a right end portion 64n located below the catalytic converter 54. The right end portion 64n protrudes rearward from the left end portion 64m and covers the catalytic converter 54 from the front and the bottom.
Further, the notch 64k may be an air passage for discharging the air around the catalytic converter 54 having a high temperature together with the traveling wind or supplying the traveling wind to the catalytic converter 54. Therefore, the catalytic converter 54 can be appropriately cooled. Further, the notch 64k may also serve as a drainage portion for preventing rainwater from accumulating at the rear end portion 64a.
By forming the rear end portion 64a of the undercover 64 in this way, the catalytic converter 54 can be covered from the front and the lower side, and the catalytic converter 54 can be protected. Further, the catalytic converter 54 is less likely to be exposed to the outside due to the rear end portion 64a of the undercover 64, and the appearance can be improved.

FIG. 4 is an enlarged view of a main part of FIG.
The catalyst converter 54 includes a columnar carrier on which a catalyst is supported and an outer cylinder 54A into which the carrier is inserted, and the outer cylinder 54A is connected to an upstream pipe 87 (see FIG. 3) and a downstream pipe 88. There is. The carrier has innumerable pores and gaps through which exhaust gas passes, and a catalytic substance made of metal or the like is supported on the inner surface of the pores or gaps.
The radiator 101 is directly attached to the side wall of the crankcase 43 of the engine 41, or the radiator 101 is attached via an intermediate member, and the outer surface of the radiator 101 is covered with the radiator cover 103. Below the radiator 101 and the radiator cover 103, a rear exhaust pipe 86 is arranged so as to extend in the front-rear direction.

The radiator 101 is provided with an upper tank and a lower tank capable of storing cooling water in the upper part and the lower part thereof, and the upper tank and the lower tank are connected by a radiator core. The radiator core includes a plurality of cooling water flow pipes capable of flowing cooling water between the upper tank and the lower tank, and cooling fins provided across the adjacent cooling water flow pipes, and cools the radiator core through the cooling water flow pipes. The cooling water is cooled by dissipating heat from the water to the outside through the cooling fins.

The upper tank of the radiator 101 communicates with a water jacket formed in the cylinder block 83 via a cooling water pipe. A thermostat (not shown) is connected to the lower tank of the radiator 101 via a first radiator hose 104. The thermostat is connected to the water jacket and the water pump in the cylinder head 46 via a pipe (not shown).
The thermostat switches the cooling water flow path between a flow path in which the cooling water flows into the radiator 101 and a flow path in which the cooling water does not flow into the radiator 101, depending on the cooling water temperature.
A water pump is connected to the lower part of the cylinder block 83 via a second radiator hose 106.

In front of the catalytic converter 54 in a side view, a cross member 81 of the front frame 21, a lower end 31a of the rear pipe 31 of the rear frame 22, and a rear end 64a of the undercover 64 are arranged. Further, in view of the side view, the crankcase 43 and the lower plate 93 of the engine 41 are arranged behind the catalytic converter 54. Further, a cylinder portion 44 (specifically, a cylinder head 46), a first radiator hose 104, and a second radiator hose 106 are arranged above the catalytic converter 54 in a side view. Further, a rear end portion 64a of the undercover 64 is arranged below the catalytic converter 54 in a side view. In this way, the catalytic converter 54 is covered in front, rear, above, and below, so that the catalytic converter 54 can be effectively protected.

Further, the space 95 formed in front of the crankcase 43 and below the cylinder portion 44 is a space formed behind the cross member 81 of the front frame 21, the lower end portion 31a of the rear frame 22, and the rear end portion 64a of the undercover 64. Is. By arranging the catalytic converter 54 so as to extend in the vehicle width direction, the space 95 can be effectively utilized.
As described above, by arranging the catalytic converter 54 below the cylinder portion 44 and in front of the crankcase 43 and the lower plate 93, the space 95 surrounded by the cylinder portion 44 and the crankcase 43 and the lower plate 93. Can be used effectively.

FIG. 5 is a right side view showing the power unit 14, the fuel tank 56, and their surroundings of the motorcycle 10, and the front frame 21 (see FIG. 1) is omitted.
The lower end 54b of the catalytic converter 54 is at the same height as the lower end 56b of the lower surface 56a of the fuel tank 56 or above the lower end 56b when the vehicle is empty and the driver is in the vehicle. Is located in. Reference numeral 107 is a horizontal line extending from the lower end 56b of the fuel tank 56.
By setting the height of the catalytic converter 54 in this way, the ground clearance of the catalytic converter 54 can be increased, and the catalytic converter 54 can be protected from protrusions from the ground, stepping stones, and the like.

One end 104a of the first radiator hose 104 is connected to the lower tank of the radiator 101, and the other end 104b is connected to the thermostat. Further, the thermostat is connected to the water pump and communicates with the water pump of the cylinder head 46.
The second radiator hose 106 has one end 106a connected to the water pump and the other end 106b communicating with the water jacket of the cylinder block 83. The water jacket of the cylinder block 83 and the water jacket of the cylinder head 46 communicate with each other.

The flow of the cooling water around the radiator 101 described above will be described below.
During normal operation after warming up the engine 41, the cooling water discharged from the water pump flows into the water jacket of the cylinder block 83 through the second radiator hose 106, and further, in the water jacket in the cylinder head 46. Inflow to. Then, it further flows into the upper tank of the radiator, and then flows from the upper tank through the radiator core into the lower tank. When the cooling water flows through the radiator core, the heat of the cooling water is released to the outside, and the temperature of the cooling water drops.
Further, the cooling water reaches the thermostat from the lower tank through the first radiator hose 104 as indicated by an arrow. In this case, since the thermostat is switched to the flow path to the water pump, the cooling water flows from the thermostat to the water pump and repeats the above circulation.

Further, during the warm-up operation immediately after the engine 41 is started, the cooling water discharged from the water pump flows into the water jacket of the cylinder block 83 through the second radiator hose 106 as shown by the arrow. Further, the cooling water flows into the water jacket in the cylinder head 46. Then, by switching the flow path by the thermostat, the cooling water flows from the water jacket in the cylinder head 46 to the thermostat through a pipe (not shown), further reaches the water pump from the thermostat, and repeats the above circulation. Therefore, the cooling water does not flow into the radiator 101 and is not cooled. Therefore, the cooling water temperature tends to rise, and warm-up is promoted.

As shown in FIGS. 4 and 5, the link member 38 is arranged above the cylinder portion 44 of the engine 41 constituting the power unit 14. The catalytic converter 54 is arranged below the cylinder portion 44 and in front of the crankcase 43 of the engine 41.
According to this configuration, since the catalytic converter 54 is arranged in the space 95 in front of the crankcase 43 below the cylinder portion 44, the space 95 can be effectively used and interference with other members can be prevented. Further, by arranging the catalytic converter 54 in the space 95 so as to extend in the vehicle width direction, the space 95 can be used more effectively, and the catalytic converter 54 can be compactly arranged in the space 95.

FIG. 6 is an enlarged view of a main part of FIG.
Draw a vehicle body front-rear center line (that is, a center line passing through the center of the width direction of the front wheels 13 (see FIG. 2) and the rear wheels 16) 110 extending forward and backward through the center of the vehicle body of the motorcycle 10 in the vehicle width direction. At that time, most of the connection portion 46A of the cylinder head 46 with the exhaust pipe 51 is arranged on one side (specifically, on the left side) of the vehicle body front-rear center line 110. Further, the catalytic converter 54 is arranged on the other side (specifically, on the right side) of the vehicle body front-rear center line 110. Further, the end portion 54c of the catalyst converter 54 outside in the vehicle width direction is located inside in the vehicle width direction with respect to one side surface 56c of the tank body 56h of the fuel tank 56.
In this way, by arranging the catalytic converter 54 between the vehicle body front-rear center line 110 and one side surface 56c of the fuel tank 56, the amount of protrusion of the front exhaust pipe 85 toward the vehicle width direction is reduced. It is possible to secure the bank angle of the vehicle. Further, the catalyst converter 54 can be compactly arranged in the space 95, and further, the portion of the space 95 where the catalyst converter 54 is not arranged can be utilized as a space for arranging other parts.

The rear end portion 64a of the undercover 64, specifically, the right end portion 64n of the rear end portion 64a covers the entire catalytic converter 54 from below in a bottom view. Therefore, the catalytic converter 54 can be protected more reliably.
The notch 64k formed in the rear end portion 64a of the undercover 64 is formed at a position overlapping with one of the pair of nuts 91 and 91 when viewed from the bottom. As a result, when the exhaust device 47 is attached to and detached from the engine 41, when one of the nuts 91 is turned by the tool 97, the tool 97 can be hung on the nut 91 through the notch 64k, which improves workability. it can.

Further, the gap between the crankcase 43 and the rear surface 64b (see FIG. 5) of the rear end portion 64a of the undercover 64 in the space 95 in the front-rear direction is larger than the outer diameter of the catalytic converter 54. Therefore, the outer diameter of the catalyst converter 54 can be increased as long as the catalyst converter 54 does not interfere with the crankcase 43 and the undercover 64, and the amount of catalyst can be increased to improve the purification performance of the catalyst converter 54.
Further, by making the cross-sectional shape of the catalytic converter 54 an ellipse or an ellipse whose major axis is horizontal or substantially horizontal, the minimum ground height of the catalytic converter 54 is made the same as that of the catalytic converter 54 having a circular cross section. Can be raised. As a result, the catalytic converter 54 can be more advantageously protected from protrusions from the ground, flying stones, and the like.

As shown in FIGS. 5 and 6, an undercover 64 is arranged below the fuel tank 56 and between the fuel tank 56 and the catalytic converter 54, respectively, and the undercover 64 has a rear end 64a as a catalyst. It is arranged in front of and below the converter 54.
According to this configuration, the undercover 64 can protect the catalytic converter 54 from external factors, and at the same time, the appearance can be improved by covering the front of the catalytic converter 54. Further, the undercover 64 makes it difficult for the running wind to hit the catalyst converter 54, and can promote the activation of the catalyst in the catalyst converter 54.

FIG. 7 is a sectional view taken along line VII-VII of FIG.
The left and right lower frames 27, 27 of the front frame 21 include a frame groove 27a formed on the upper surface so as to extend in the front-rear direction, and an outer flange portion 27b extending outward in the vehicle width direction from the upper edge of the outer surface.
The rear frame 22 includes a rear pipe 31 that is inclined downward and forward, and a support frame 34 that is attached to the upper part of the rear pipe 31. The rear pipe 31 is made of a round pipe, and the support frame 34 is a member having a cross-section channel shape including a bottom wall and a pair of side walls raised from both edges of the bottom wall. The left and right support frames 34, 34 are fastened with bolts and nuts at the rear ends of the left and right lower frames 27, 27, respectively.

The undercover 64 includes a center cover portion 64c having a cup-shaped cross section provided in the central portion, and mounting flange portions 64d and 64d extending from the upper portion of the center cover portion 64c to both sides.
The center cover portion 64c includes a bottom wall 64e forming a bottom portion and a pair of left and right side walls 64f and 64f raised from both ends of the bottom wall 64e. The mounting flange portion 64d includes an inner flat portion 64g extending outward in the vehicle width direction from the upper edge of the side wall 64f, a downward protruding portion 64h protruding downward from the outer edge of the inner flat portion 64g, and an outer surface upper edge of the downward protruding portion 64h. An outer flat portion 64j extending outward in the vehicle width direction is integrally formed.

The undercover 64 is mounted with the downward protrusions 64h and 64h of the left and right mounting flanges 64d and 64d inserted into the frame groove 27a of the lower frame 27 of the front frame 21. The bottom wall 64e of the undercover 64 is located above the cross member 81 of the front frame 21.
Further, the floor step 63 is supported by the mounting flange portions 64d and 64d of the undercover 64. Specifically, in the floor step 63, a plurality of columnar portions 63a projecting downward are integrally formed on the lower surface thereof, and the lower ends of the columnar portions 63a are mounting flange portions 64d and 64d of the undercover 64 (specifically, the outer flat portion 64j). , 64j) is applied to the upper surface. Then, screws penetrating the outer flange portions 27b, 27b and the outer flat portions 64j, 64j of the front frame 21 are screwed into the columnar portion 63a from below. That is, the floor step 63 is supported by the front frame 21 via the undercover 64.

When the vehicle body vertical center line (center line extending in the vertical direction through the vehicle body front-rear center line 110 (see FIG. 6)) 111 extending in the vertical direction through the center of the vehicle body in the vehicle width direction is drawn, the catalytic converter 54 It is arranged on one side (specifically, on the right side) of the vehicle body vertical center line 111. Further, the catalytic converter 54 is arranged horizontally or substantially horizontally. Thereby, the minimum ground clearance of the catalytic converter 54 can be increased.
_{An oxygen sensor (O 2} sensor) 108 that detects the oxygen concentration in the exhaust is attached to the upstream pipe 87 of the front exhaust pipe 85 so as to extend in the vehicle width direction on the outer peripheral surface thereof and on the side where the catalytic converter 54 is located. Has been done. In this way, the oxygen sensor 108 is covered from below by the upstream pipe 87 extending downward and to the right from the lower surface of the cylinder head 46 and the catalytic converter 54, so that the oxygen sensor 108 is protected from flying stones and the like. Can be done.
The catalyst converter 54 is arranged as a whole in front view inside the contours of the front frame 21, the fuel tank 56, and the undercover 64. Thereby, the catalytic converter 54 can be protected from external factors from the front of the vehicle (for example, an object lying on the ground, an object protruding from the ground, an object scattered from the front of the vehicle).

As shown in FIGS. 1, 5 and 7, the motorcycle 10 as a saddle-riding vehicle includes a body frame 11, a seat 17 supported by the body frame 11, and a body frame 11 in front of the seat 17. It is provided with a floor step 63 as a footrest provided at the lower part.
Further, the motorcycle 10 is swingably supported by the fuel tank 56 arranged below the floor step 63 and the vehicle body frame 11 arranged behind the floor step 63 and the fuel tank 56 via the link member 38. The power unit 14 is provided. Further, the motorcycle 10 includes an exhaust pipe 51 connected to the power unit 14, a silencer 52 connected to the exhaust pipe 51, and a catalytic converter 54 provided in the exhaust pipe 51.
The catalytic converter 54 is arranged behind the fuel tank 56 so that the longitudinal direction of the catalytic converter 54 faces the vehicle width direction and the entire catalytic converter 54 overlaps the fuel tank 56 when viewed from the front of the vehicle. To.

According to this configuration, since the catalytic converter 54 does not protrude outward from the fuel tank 56 in the vehicle width direction, it is possible to easily secure the bank angle of the motorcycle 10. Further, since the fuel tank 56 is located in front of the catalyst converter 54, it is possible to make it difficult for the running wind to hit the catalyst converter 54, and it is possible to easily activate the catalyst converter 54. Further, by arranging the entire catalytic converter 54 behind the fuel tank 56, the catalytic converter 54 is not exposed from the fuel tank 56, so that the fuel tank 56 can protect the catalytic converter 54 from external factors.

Further, as shown in FIGS. 6 and 7, an oxygen sensor 108 is arranged in the middle of the exhaust pipe 51, specifically, in the upstream pipe 87 attached to the cylinder head 46, and the oxygen sensor 108 has a vehicle width in the longitudinal direction thereof. Arranged in the direction. Further, in bottom view, it is arranged above the catalytic converter 54 so as to overlap the upstream pipe 87 and at least a part of the catalytic converter 54.
According to this configuration, the oxygen sensor 108 can be protected by covering it from below with the catalytic converter 54 and the upstream pipe 87.

<Second Embodiment>
FIG. 8 is a right side view (second embodiment) of a main part of a motorcycle 120 having an exhaust structure according to the present invention. The same components as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.
In front of the catalytic converter 54, an undercover 124 that covers the lower part of the fuel tank 56 (see FIG. 5) is arranged.
The undercover 124 differs from the undercover 64 of the first embodiment (see FIGS. 4 and 5) only in the rear end portion 124a.
That is, the rear end portion 124a of the undercover 124 is arranged in front of the catalyst converter 54 and covers a part of the front side of the catalyst converter 54 from below. The catalytic converter 54 is located above the lower end 124b of the rear end 124a. By providing the rear end portion 124a of the undercover 124 in this way, the catalytic converter 54 can be protected from the front and the lower side by the rear end portion 124a of the undercover 124.

FIG. 9 is a bottom view showing the catalytic converter 54, the undercover 124, and the surroundings thereof.
The rear end portion 124a of the undercover 124 covers the front portion of the catalytic converter 54 from below. A notch 124k is formed at the center of the rear end portion 124a in the vehicle width direction so as to overlap one of the pair of nuts 91 and 91 when viewed from the bottom.
The notch 124k is a portion through which a tool 97 used for turning the nut 91 is passed, and is formed so as to open to the rear of the vehicle.
Further, the notch 124k does not overlap with the catalyst converter 54 when viewed from the bottom, and the notch 124k is offset in the vehicle width direction (specifically, to the left) with respect to the catalyst converter 54. Therefore, it is possible to prevent stepping stones and the like from hitting the catalyst converter 54 through the notch 124k from the front of the vehicle.

In this way, the front exhaust pipe 85 is fastened to the cylinder head 46 of the engine 41 with the nut 91 as a fastening member, and the undercover 124 is formed with a notch 124k through which the tool 97 for turning the nut 91 is passed. From the bottom view, the notch 124k is formed so as to overlap the nut 91 and not to overlap the catalytic converter 54.
By providing the notch 124k, the exhaust device 47 can be moved closer to the catalytic converter 54 without removing the undercover 124 and the like when performing maintenance or replacement of the exhaust device 47 (see FIG. 1). It can be easily attached and detached. As a result, workability can be improved while making it easier to protect the catalytic converter 54.

The above-described embodiment shows only one aspect of the present invention, and can be arbitrarily modified and applied without departing from the gist of the present invention.
For example, in the above embodiment, as shown in FIG. 6, the catalytic converter 54 is arranged so as to extend in the vehicle width direction, but if the catalytic converter 54 is arranged in the space 95, the catalytic converter 54 is arranged in the vehicle width direction. You may tilt against. Further, as shown in FIG. 7, the catalytic converter 54 is arranged horizontally or substantially horizontally, but if the entire catalytic converter 54 overlaps with the fuel tank 56 when viewed from the front of the vehicle, the catalytic converter 54 is placed horizontally. You may tilt it greatly.
The present invention is not limited to the case where it is applied to motorcycles 10, 120 which are saddle-riding vehicles, but is also applicable to saddle-riding vehicles other than motorcycles 10, 120. The saddle-riding type vehicle includes all vehicles that ride across the vehicle body, and is not only a motorcycle (including a motorized bicycle) but also a three-wheeled vehicle or an four-wheeled vehicle classified as an ATV (rough terrain vehicle). It is a vehicle including.

10,120 Motorcycles (saddle-riding vehicles)
11 Body frame 14 Power unit 17 Seat 38 Link member 41 Engine 43 Crankcase 51 Exhaust pipe 52 Muffler 54 Catalytic converter 56 Fuel tank 63 Floor step (footrest)
64,124 Undercover 64k, 124k Notch 108 Oxygen sensor 110 Body front and rear center line (body center line)
111 Body top and bottom center line (body center line)

Claims (6)

A vehicle body frame (11), a seat (17) supported by the vehicle body frame (11), and a footrest portion (63) provided in front of the seat (17) and below the vehicle body frame (11). A fuel tank (56) arranged below the footrest portion (63), and a link member (11) arranged behind the footrest portion (63) and the fuel tank (56) and attached to the vehicle body frame (11). A power unit (14) swingably supported via the 38), an exhaust pipe (51) connected to the power unit (14), and a silencer (52) connected to the exhaust pipe (51). In the exhaust structure of a saddle-riding vehicle including a catalytic converter (54) provided in the middle of the exhaust pipe (51) so as to extend in the vehicle width direction.
The exhaust pipe (51) extends downward from the lower surface of the cylinder head (46) and is curved to one side in the vehicle width direction to extend and is connected to the other end of the catalytic converter (54). 87) and a downstream pipe (88) extending from one end of the catalytic converter (54) to one side in the vehicle width direction and curved rearward.
The catalytic converter (54) is arranged so that its longitudinal direction faces the vehicle width direction and the entire catalytic converter (54) overlaps the fuel tank (56) when viewed from the front of the vehicle. (54) is arranged behind the fuel tank (56).
When the vehicle body vertical center line (111) extending in the vertical direction is drawn through the center of the vehicle body in the vehicle width direction, the catalytic converter (54) is on one side in the vehicle width direction with respect to the vehicle body vertical center line (111). Placed on the side,
An oxygen sensor (108) is arranged in the middle of the upstream pipe (87) , and the oxygen sensor (108) is arranged with its longitudinal direction facing the vehicle width direction, and the catalytic converter (54) is viewed from the bottom. ) Above the catalytic converter (54) so as to overlap at least a part of the catalyst converter (54) .
Said catalytic converter (54) is greater cross-sectional shape than the exhaust pipe (51), the cross-sectional shape of the catalytic converter (54), Rukoto major axis is horizontal or substantially horizontal elliptical or oval The exhaust structure of a saddle-mounted vehicle featuring. The catalytic converter (54) is placed between the vehicle body front-rear center line (110) extending to the front and rear of the vehicle body through the center of the vehicle body in the vehicle width direction and one side surface (56c) of the fuel tank (56) in the vehicle width direction. The exhaust structure for a saddle-mounted vehicle according to claim 1, wherein the vehicle is arranged in the vehicle width direction. An undercover (64,124) is arranged below the catalytic converter (54) between the catalytic converter (54) and the fuel tank (56), and the undercover (64,124) is the undercover (64,124). Arranged so as to overlap with the catalytic converter (54) when viewed from the bottom.
The rear surface (64b) of the rear end portion (64a) of the undercover (64) is formed so as to wrap around the catalytic converter (54) from the front to the lower side and covers the catalytic converter (54).
The saddle-riding vehicle according to claim 2, wherein the link member (38) is arranged above the cylinder portion (44) of the engine (41) constituting the power unit (14). Exhaust structure. A vehicle body frame (11), a seat (17) supported by the vehicle body frame (11), and a footrest portion (63) provided in front of the seat (17) and below the vehicle body frame (11). A fuel tank (56) arranged below the footrest portion (63), and a link member (11) arranged behind the footrest portion (63) and the fuel tank (56) and attached to the vehicle body frame (11). A power unit (14) swingably supported via the 38), an exhaust pipe (51) connected to the power unit (14), and a silencer (52) connected to the exhaust pipe (51). In the exhaust structure of a saddle-mounted vehicle including a catalytic converter (54) provided in the exhaust pipe (51).
The catalytic converter (54) is arranged so that its longitudinal direction faces the vehicle width direction and the entire catalytic converter (54) overlaps the fuel tank (56) when viewed from the front of the vehicle. (54) is arranged behind the fuel tank (56).
When the vehicle body vertical center line (111) extending in the vertical direction is drawn through the center of the vehicle body in the vehicle width direction, the catalytic converter (54) is on one side in the vehicle width direction with respect to the vehicle body vertical center line (111). Placed on the side,
An undercover (64,124) is arranged below the catalytic converter (54) between the catalytic converter (54) and the fuel tank (56), and the undercover (64,124) is the undercover (64,124). Arranged so as to overlap with the catalytic converter (54) when viewed from the bottom.
The rear surface (64b) of the rear end portion (64a) of the undercover (64) is formed so as to wrap around the catalytic converter (54) from the front to the lower side and covers the catalytic converter (54).
The exhaust structure of a saddle-riding vehicle, wherein the link member (38) is arranged above the cylinder portion (44) of the engine (41) constituting the power unit (14). A cross member (81) is arranged between the catalytic converter (54) and the fuel tank (56), and the undercover (64, 124) extends rearward from the cross member (81) side. The exhaust structure of the saddle-riding vehicle according to claim 3 or 4. The exhaust pipe (51) is fastened to the power unit (14) with a fastening member (91), and a notch (64k) is passed through the undercover (64, 124) through a tool (97) for turning the fastening member (91). , 124k) is formed, and the notch (64k, 124k) is formed so as to overlap the fastening member (91) and not to overlap the catalytic converter (54) in bottom view. Item 5. The exhaust structure of the saddle-riding vehicle according to item 5.

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