CN112351935A

CN112351935A - Oxygen sensor arrangement structure of motorcycle

Info

Publication number: CN112351935A
Application number: CN201880095140.8A
Authority: CN
Inventors: 仓泽侑史; 久保俊博
Original assignee: Honda Motor Co Ltd
Current assignee: Honda Motor Co Ltd
Priority date: 2018-08-15
Filing date: 2018-08-15
Publication date: 2021-02-09
Anticipated expiration: 2038-08-15
Also published as: BR112021001721A2; DE112018007907T5; WO2020035921A1; BR112021001721B1; CN112351935B

Abstract

An arrangement structure of an oxygen sensor (25) of a motorcycle (1), wherein the motorcycle (1) is provided with a catalyst (14) in the middle of an exhaust pipe (13) extending from an engine (12), and the oxygen sensor (25) is mounted on the exhaust pipe (13) at the downstream side of the catalyst (14), and the following structure is adopted as the arrangement structure of the oxygen sensor (25): the oxygen sensor (25) is disposed on the inside of the exhaust pipe (13) in the vehicle width direction and at a position overlapping the engine (12) in a plan view, and a protective wall (29) for protecting the oxygen sensor (25) is attached to the exhaust pipe (13) in front of the oxygen sensor (25). Thus, an oxygen sensor arrangement structure for a motorcycle is provided, which can protect the oxygen sensor from the influence of the disturbance of flying stones and the like in all motorcycles regardless of the form of the motorcycle.

Description

Oxygen sensor arrangement structure of motorcycle

Technical Field

The present invention relates to an arrangement structure of an oxygen sensor for detecting an oxygen concentration of exhaust gas discharged from an engine of a motorcycle.

Background

In a motorcycle, in order to improve properties of exhaust gas discharged from an engine and to improve fuel consumption, the following are performed: the oxygen concentration of the exhaust gas is detected by an oxygen sensor, and the amount of fuel supplied to the engine is controlled so that the air-fuel ratio (A/F) calculated based on the detected oxygen concentration becomes the target air-fuel ratio.

In addition, the deterioration of the catalyst provided in the middle of the exhaust pipe is also detected by the oxygen sensor. In this case, the oxygen sensor is disposed on the downstream side of the catalyst in the exhaust pipe (on the downstream side in the exhaust gas flow direction), and the degree of deterioration of the catalyst is detected from the oxygen concentration in the exhaust gas detected by the oxygen sensor.

However, patent document 1 proposes a structure for protecting an oxygen sensor mounted on an exhaust pipe from flying stones and the like. Specifically, the following structure is proposed: an oxygen sensor is mounted on a collection portion where a plurality of exhaust pipes extending from a multi-cylinder engine are collected, and the oxygen sensor is disposed on an upper wall portion of a rear extension portion (exhaust passage inclined portion) of the collection portion of the exhaust pipes, the upper wall portion being located behind a cross member and the engine that connect a pair of left and right frame members to each other.

According to the above configuration, since the lower side of the oxygen sensor is covered by the rear extension portion of the exhaust pipe collecting portion or the large stay located at the storage time position, and the front side is covered by the engine and the cross member, the oxygen sensor can be protected from flying stones and the like and prevented from being damaged.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 2008-069705

Disclosure of Invention

Problems to be solved by the invention

However, the rear extension portion of the exhaust pipe collecting portion, the large stay at the storage position, the engine, and the cross member in patent document 1 partially cover the oxygen sensor only at a position away from the oxygen sensor, and therefore the oxygen sensor cannot be effectively protected. Further, the structure proposed in patent document 1 has the following problems: the present invention is not applicable to a motorcycle having a structure other than the above-described one, but is limited to a motorcycle provided with a multi-cylinder engine having a plurality of exhaust pipes extending therethrough and a cross member connecting left and right frame members to each other. The oxygen sensor in patent document 1 detects the oxygen concentration in the exhaust gas in order to calculate the air-fuel ratio.

The present invention has been made in view of the above problems, and an object of the present invention is to provide an oxygen sensor arrangement structure for a motorcycle, which can protect an oxygen sensor from disturbance such as flying stones in all motorcycles regardless of the form of the motorcycle.

Means for solving the problems

In order to achieve the above object, the present invention provides an oxygen sensor arrangement structure for a motorcycle having a catalyst provided in an exhaust pipe extending from an engine and an oxygen sensor mounted on the exhaust pipe downstream of the catalyst, wherein the oxygen sensor is disposed at a position on the inside of the exhaust pipe in a vehicle width direction and overlapping the engine in a front view, and a protective wall for protecting the oxygen sensor is mounted on the exhaust pipe in front of the oxygen sensor.

A second feature of the present invention is that, in addition to the first feature, the protective wall has a curved shape.

A third aspect of the present invention is summarized as the first or second aspect, wherein a sensor boss is attached to the exhaust pipe from the exhaust pipe toward an inside in a vehicle width direction, the sensor boss is disposed at a position overlapping with the engine in a plan view, and the oxygen sensor is attached to the sensor boss.

A fourth aspect of the present invention is summarized as that in any one of the first to third aspects, a cover member is attached to the exhaust pipe so as to cover an outer portion of the exhaust pipe, and the cover member is disposed at a position overlapping with the oxygen sensor in a side view.

In addition to the fourth feature, according to a fifth feature of the present invention, the cover member is attached to the exhaust pipe at two locations, i.e., a front and a rear, via fastening portions, and the oxygen sensor is disposed between the fastening portions in a front-rear direction.

A sixth aspect of the present invention is summarized as that in any one of the first to fifth aspects, wherein the oxygen sensor is disposed on an inner side of a brake pedal in a vehicle width direction.

A seventh aspect of the present invention is summarized as that in any one of the first to sixth aspects, in which the catalyst is disposed in front of the engine in a side view, and the oxygen sensor is disposed below the engine.

An eighth aspect of the present invention is summarized as the any one of the first to seventh aspects, wherein the oxygen sensor is disposed on an innermost side of the exhaust pipe in a plan view.

A ninth aspect of the present invention is summarized as any one of the first to eighth aspects, wherein an angle formed by a central axis of the oxygen sensor and a horizontal plane is 45 degrees or less.

The second oxygen sensor 25 of the embodiment corresponds to the oxygen sensor of the present invention.

Effects of the invention

According to the first aspect of the present invention, the oxygen sensor is disposed on the vehicle width direction inner side of the exhaust pipe and at a position overlapping the engine in a plan view, and the protection wall for protecting the oxygen sensor is attached to the exhaust pipe in front of the oxygen sensor. In particular, since the front portion of the oxygen sensor is protected by the protective wall, damage to the oxygen sensor due to interference of stones (flying stones) or water jumping from the front wheel can be effectively prevented.

Further, since the oxygen sensor is disposed on the vehicle width direction inner side of the exhaust pipe, the oxygen sensor does not protrude laterally, and the oxygen sensor can be disposed compactly.

Further, since the oxygen sensor is disposed in a portion of the exhaust pipe surrounding the high-temperature engine, which overlaps with the engine in a plan view, the oxygen concentration of the high-temperature exhaust gas that is not rapidly cooled can be detected. In addition, in the case where the deterioration of the catalyst is detected by the oxygen sensor, it is desirable to detect the oxygen concentration of the exhaust gas in a high temperature state.

The above effects can be obtained for all motorcycles regardless of the form of the motorcycle (for example, the engine form, the body frame structure, and the like).

According to the second feature of the present invention, since the protection wall has a curved shape, the oxygen sensor can be protected from interference from outside (for example, below) the front. In addition, since the rigidity of the protection wall is improved, the deformation of the protection wall can be prevented.

According to the third aspect of the present invention, the sensor boss is attached to the exhaust pipe from the exhaust pipe toward the inside in the vehicle width direction, and the oxygen sensor is attached to the sensor boss, so that the side of the oxygen sensor is protected by the exhaust pipe. Further, since the sensor boss is disposed at a position overlapping the engine in a plan view, the oxygen sensor mounted on the sensor boss is protected from above by the engine.

According to the fourth aspect of the present invention, since the cover member covering the outer portion of the exhaust pipe is disposed at a position overlapping the oxygen sensor in a side view, the oxygen sensor is also protected from the side by the cover member.

According to the fifth aspect of the present invention, since the oxygen sensor is disposed between the front and rear fastening portions (the reinforced portion of the cover member) for firmly attaching the cover member to the exhaust pipe, the oxygen sensor is further protected by the cover member.

According to a sixth feature of the present invention, the side of the oxygen sensor is also protected by the brake pedal.

According to the seventh aspect of the present invention, since the catalyst and the oxygen sensor are disposed in the vicinity of the engine in a compact manner, the concentration of oxygen contained in the high-temperature exhaust gas can be detected with high accuracy.

According to the eighth aspect of the present invention, since the oxygen sensor is disposed on the innermost side of the exhaust pipe in a front view, the oxygen sensor can be disposed compactly without increasing the width of the motorcycle.

According to the ninth aspect of the present invention, since the angle formed by the center axis of the oxygen sensor and the horizontal plane is set to 45 degrees or less, the vehicle body can be made compact in the vertical direction.

Drawings

Fig. 1 is a right side view of a motorcycle having an oxygen sensor arrangement structure according to the present invention.

Fig. 2 is an enlarged detail view of a main part of the motorcycle shown in fig. 1.

Fig. 3 is a view from the direction of 3 in fig. 2 (bottom view).

Fig. 4 is a cross-sectional view taken along line 4-4 of fig. 3.

Fig. 5 is a perspective view of the oxygen sensor and the protection wall as viewed obliquely from the left rear.

Fig. 6 is a plan view of the exhaust pipe.

Fig. 7 is a side view of the cover member.

Description of the reference numerals

1 Motor two-wheeled vehicle

12 engine

13 exhaust pipe

14 catalyst

23 brake pedal

25 second oxygen sensor (oxygen sensor)

26 cover component

26a mounting part

28 sensor boss

29 protective wall

Detailed Description

Embodiments of the present invention will be described below with reference to the drawings. In the following description, front-back, left-right, and up-down refer to directions viewed from a passenger seated in a motorcycle equipped with an internal combustion engine.

[ integral Structure of motorcycle ]

First, the overall structure of a motorcycle having the oxygen sensor arrangement structure of the present invention will be described below with reference to fig. 1.

That is, fig. 1 is a right side view of the motorcycle 1, and in the motorcycle 1 shown in the figure, 2 is a head pipe positioned at an upper portion in front of a vehicle body (right side in fig. 1 is a front of the vehicle body), and a steering shaft (not shown) is rotatably inserted into the head pipe 2. A steering handle 3 is attached to an upper end of the steering shaft. An upper end of a front fork 4 is attached to a lower end of the steering shaft, and a front wheel WF as a steering wheel is rotatably supported by a lower end of the front fork 4 via a front axle 5.

The main frame 6 extends obliquely downward from the head pipe 2 toward the rear of the vehicle body (leftward in fig. 1) in a side view, and the down tube 7 extends obliquely downward from the head pipe 2 toward the rear of the vehicle body in a side view.

A pair of left and right pivot frames 9 bent into a shape of "く" in side view are integrally continuous with the rear end portions of the main frames 6, and the front ends of a pair of left and right seat rails 8 extending substantially horizontally toward the rear of the vehicle are bonded to the bent portions, respectively. The lower end portions of the left and right pivot frames 9 are bent in a shape of "く" in side view, and a pair of left and right brackets 9' are bonded to the lower end portions thereof, respectively. Further, a pair of left and right seat stays 10 extend obliquely upward in the vehicle body rear direction from the bent portions of the pivot frames 9, and the rear ends of the seat stays 10 are bonded to the pair of left and right seat rails 8, respectively.

The body frame 11 of the motorcycle 1 is constituted by the head pipe 2, the main frame 6, the down tube 7, the seat rail 8, the pivot frame 9, and the seat stay 10 described above.

An engine (in the illustrated example, an air-cooled four-stroke single cylinder engine) 12 as a driving source is housed and supported in a space sandwiched between the pair of left and right pivot frames 9 and the down tube 7 constituting the vehicle body frame 11. An exhaust pipe 13 is connected to an unillustrated exhaust port provided in a cylinder head 12a of the engine 12, and the exhaust pipe 13 extends obliquely downward in the vehicle body rear direction from the engine 12, and then bends toward the vehicle body rear side and extends substantially horizontally toward the vehicle body rear side. A catalyst 14 for purifying the exhaust gas flowing through the exhaust pipe 13 is provided in an inclined portion 13a of the exhaust pipe 13 extending obliquely downward from the engine 12, and a muffler (muffler) 15 is attached to a rear end portion of a horizontal portion 13b of the exhaust pipe 13 extending substantially horizontally rearward of the vehicle body from the catalyst 14.

A fuel tank 16 supported by the main frame 6 is disposed above the engine 12, and a seat 17 supported by the seat rail 8 is disposed behind the fuel tank 16.

Further, the front end of the swing arm 18 is pivotally supported by a pair of left and right brackets 9' bonded to the lower end of the pivot frame 9 by a pivot shaft 19. The swing arm 18 is supported to be vertically swingable about a pivot shaft 19, and a rear wheel WR as a driving wheel is rotatably supported by a rear axle 20 at a rear end portion of the swing arm 18. The swing arm 18 and the rear wheel WR pivotally supported at the rear end of the swing arm 18 are suspended on the vehicle body by a pair of right and left rear shock absorbers (hydraulic shock absorbers) 21 suspended between the swing arm 18 and the seat stay 10.

In the motorcycle 1 shown in fig. 1, a pair of left and right pedals 22 (only one of which is shown in fig. 1) for placing the driver's feet thereon are provided at lower portions on both sides of the vehicle body, more specifically, at positions above the horizontal portion 13b of the exhaust pipe 13 and between the catalyst 14 and the bracket 9 in the front-rear direction of the vehicle body. Further, in the vicinity of the pedal 22 on the right side (the near side in fig. 1), more specifically, a brake pedal 23 is disposed at a position substantially at the same height as the horizontal portion 13b of the exhaust pipe 13 below the pedal 22, and the brake pedal 23 is supported to be turnable about a pedal shaft 23' for applying braking to the rotation of the rear wheel WR when the driver steps on the brake pedal 23.

However, in the motorcycle 1 of the present embodiment, a first oxygen sensor 24 for detecting the oxygen concentration of the exhaust gas discharged from an unillustrated exhaust port is attached to the exhaust pipe 13 on the upstream side (upstream side in the flow direction of the exhaust gas) of the catalyst 14. The first oxygen sensor 24 is a member that detects the oxygen concentration of the exhaust gas, and the oxygen concentration detected by the first oxygen sensor 24 is sent to an ECU (Electronic Control Unit), not shown. Then, the ECU calculates the air-fuel ratio (A/F) of the mixture based on the detection result of the oxygen concentration, and controls the fuel injection amount to the engine so that the air-fuel ratio becomes the target air-fuel ratio.

Further, a second oxygen sensor 25 different from the first oxygen sensor 24 is mounted on the exhaust pipe 13 on the downstream side (downstream side in the exhaust gas flow direction) of the catalyst 14. The second oxygen sensor 25 is a member that detects the oxygen concentration of the exhaust gas after passing through the catalyst 14, and the oxygen concentration of the exhaust gas detected by the second oxygen sensor 25 is sent to an ECU, not shown. Then, the ECU determines the degree of deterioration of the catalyst 14 based on the oxygen concentration detected by the second oxygen sensor 25.

The present invention relates to the arrangement structure of the second oxygen sensor 25, and details of the structure will be described below with reference to fig. 2 to 7.

[ arrangement Structure of second oxygen sensor ]

Fig. 2 is an enlarged detail view of a main part of the motorcycle shown in fig. 1, fig. 3 is a view from the direction of 3 in fig. 2 (bottom view), fig. 4 is a cross-sectional view taken along line 4-4 in fig. 3, fig. 5 is a perspective view of the second oxygen sensor and the protective wall as viewed from the oblique rear left, fig. 6 is a plan view of the exhaust pipe, and fig. 7 is a side view of the cover member.

In the present embodiment, as shown in fig. 2 to 6, the second oxygen sensor 25 for detecting degradation of the catalyst 14 is disposed at a position on the exhaust pipe 13 on the vehicle width direction inner side of the exhaust pipe 13 on the downstream side of the catalyst 14 and overlapping the engine 12 in a plan view.

As shown in fig. 2 to 5, a semi-cylindrical cover member 26 is attached to the horizontal portion 13b of the exhaust pipe 13 so as to cover the outer side portion of the horizontal portion 13 b. Here, as shown in fig. 7, mounting portions 26a having a substantially circular shape and a concave shape are formed at two positions in the vehicle body longitudinal direction of the cover member 26, and a mounting hole 26b having a circular hole shape is formed at the center of each mounting portion 26 a. The cover member 26 is attached to the exhaust pipe 13 by bolts 27 inserted through the attachment holes 26b at two positions in the vehicle body longitudinal direction while covering the horizontal portion 13b of the exhaust pipe 13 from the outside, and covers and protects the outer side surface of the horizontal portion 13b of the exhaust pipe 13. As shown in fig. 7, a recess 26c for avoiding interference with the right pedal 22 (see fig. 1) in a state where the cover member 26 is attached to the exhaust pipe 13 is formed in an upper portion of the cover member 26.

Here, the positional relationship between the cover member 26 and the second oxygen sensor 25 will be described, and the cover member 26 is disposed at a position overlapping the second oxygen sensor 25 in a side view. In other words, the second oxygen sensor 25 is disposed inside the cover member 26 at a position overlapping the cover member 26 in a side view, more specifically, between the mounting portions 26a at two positions in the front-rear direction of the vehicle body, which are the mounting positions of the cover member 26 to the exhaust pipe 13.

Next, a mounting structure of the second oxygen sensor 25 will be explained.

As shown in fig. 4 to 6, a cylindrical sensor boss 28 is attached to the inner surface of the horizontal portion 13b of the exhaust pipe 13 so as to be inclined obliquely upward from the exhaust pipe 13 toward the inside, and the sensor boss 28 is disposed at a position overlapping the engine 12 in a bottom view. The second oxygen sensor 25 is attached to the sensor boss 28 so as to be inclined obliquely upward. Here, a screw hole (not shown) communicating with the inside of the exhaust pipe 13 is formed in the sensor boss 28, and the second oxygen sensor 25 is attached to the sensor boss 28 by screwing the second oxygen sensor 25 into the screw hole of the sensor boss 28 in a state where a detection portion (not shown) at the tip end of the second oxygen sensor 25 passes through the screw hole and faces the inside of the exhaust pipe 13. A signal cable 25 'is led out from the second oxygen sensor 25, and the signal cable 25' is connected to an ECU not shown. When the vehicle body is oriented in the vertical direction, the angle α formed by the central axis l of the second oxygen sensor 25 and the horizontal plane H is set to 45 degrees or less.

As described above, as shown in fig. 3 to 5, the second oxygen sensor 25 attached to the inner surface of the horizontal portion 13b of the exhaust pipe 13 via the sensor boss 28 so as to be inclined obliquely upward toward the inside is disposed on the vehicle width direction inside of the brake pedal 23, that is, on the innermost side of the horizontal portion 13b of the exhaust pipe 13 in a plan view. Further, the second oxygen sensor 25 is disposed between the pedal 22 and the brake pedal 23 in the up-down direction as shown in fig. 2, and is disposed so as to overlap the vehicle body center line CL as shown in fig. 4. Thus, the second oxygen sensor 25 is disposed near the center of the vehicle without protruding to the left and right.

Here, as shown in fig. 2, the catalyst 14 is disposed in front of the engine 12 in a side view, and the second oxygen sensor 25 attached to the horizontal portion 13b of the exhaust pipe 13 on the downstream side of the catalyst 14 is disposed below the engine 12.

Next, a protective structure of the second oxygen sensor 25 will be explained.

As shown in fig. 3, 4, and 6, a protective wall 29 for protecting the second oxygen sensor 25 is attached to the horizontal portion 13b of the exhaust pipe 13 in front of the second oxygen sensor 25 by welding or the like. The protective wall 29 is attached obliquely along the attachment angle of the second oxygen sensor 25, and in the present embodiment, the protective wall 29 has a shape curved in an L shape in side view, and is configured by a front wall 29a for covering the second oxygen sensor 25 from the front to protect the protective wall 29 and a lower wall 29b for covering the second oxygen sensor 25 from below to protect the protective wall 29 (see fig. 6). That is, since the second oxygen sensor 25 is disposed so as to overlap the protective wall 29 when the vehicle is viewed from the front and from the bottom, the second oxygen sensor 25 can be protected.

As described above, in the arrangement structure of the second oxygen sensor 25 according to the present embodiment, the second oxygen sensor 25 is arranged at the position on the vehicle width direction inner side of the exhaust pipe 13 and overlapping the engine 12 in a plan view, and the protective wall 29 for protecting the second oxygen sensor 25 is attached to the exhaust pipe 13 in front of the second oxygen sensor 25, so that the second oxygen sensor 25 is protected from both the left and right sides, the upper side, and the front side. In particular, since the front and lower sides of the second oxygen sensor 25 are protected by the front wall 29a and the lower wall 29b of the protection wall 29, respectively, damage to the second oxygen sensor 25 due to interference of stones (flying stones) or water jumping from the front wheel WF can be effectively prevented.

Further, since the second oxygen sensor 25 is disposed on the vehicle width direction inner side of the exhaust pipe 13, the second oxygen sensor 25 does not protrude laterally, and the second oxygen sensor 25 can be disposed compactly. Further, since the second oxygen sensor 25 is disposed obliquely upward from the horizontal portion 13b of the exhaust pipe 13 toward the inside, the distance from the second oxygen sensor 25 to the road surface can be obtained. Further, since the angle α formed by the central axis l of the second oxygen sensor 25 and the horizontal plane H is set to 45 degrees or less when the vehicle body is oriented in the vertical direction, the vehicle can be made compact in the vertical direction.

Further, since the second oxygen sensor 25 is disposed in a portion overlapping the engine 12 when the exhaust pipe 13 surrounding the high-temperature engine 12 is viewed from above, the oxygen concentration of the high-temperature exhaust gas that is not rapidly cooled can be detected, and the degree of deterioration of the catalyst 14 can be detected with high accuracy by the second oxygen sensor 25.

Further, the above-described effects can be obtained for all motorcycles regardless of the form of the motorcycle (for example, the engine form, the vehicle body frame structure, and the like), and therefore the arrangement structure of the second oxygen sensor 25 of the present invention has high versatility.

In the present embodiment, since the protection wall 29 is formed in an L-shape in side view by bending the front wall 29a and the lower wall 29b, the rigidity of the protection wall 29 is improved and deformation thereof can be prevented.

In the present embodiment, the sensor boss 28 is attached to the exhaust pipe 13 from the exhaust pipe 13 toward the inside, and the second oxygen sensor 25 is attached to the sensor boss 28, so that the side of the second oxygen sensor 25 is protected by the exhaust pipe 13. Since the sensor boss 28 is disposed at a position overlapping the engine 12 in a bottom view, the second oxygen sensor 25 attached to the sensor boss 28 is protected from above by the engine 12.

Further, in the present embodiment, since the cover member 26 covering the outer portion of the exhaust pipe 13 is disposed at a position overlapping the second oxygen sensor 25 in a side view, the second oxygen sensor 25 is also protected from the side by the cover member 26. Further, since the second oxygen sensor 25 is disposed between the two front and rear attachment portions 26a for firmly attaching the cover member 26 to the exhaust pipe 13 (the reinforced portion of the cover member 26), the second oxygen sensor 25 is more reliably protected by the cover member 26. In particular, in the present embodiment, the second oxygen sensor 25 is disposed between the pedal 22 and the brake pedal 23 in the vertical direction, so that the second oxygen sensor 25 can be disposed compactly. In addition, since the second oxygen sensor 25 is disposed on the innermost side of the exhaust pipe 13 in a front view, the second oxygen sensor 25 can be disposed compactly without increasing the width of the motorcycle 1.

In the present embodiment, since the second oxygen sensor 25 is disposed on the vehicle width direction inner side of the brake pedal 23, the side of the second oxygen sensor 25 is also protected by the brake pedal 23.

In the present embodiment, since the catalyst 14 and the second oxygen sensor 25 are disposed in the vicinity of the engine 12 in a compact manner, the oxygen concentration contained in the high-temperature exhaust gas can be detected, and the degree of deterioration of the catalyst 14 can be determined with high accuracy based on the detected oxygen concentration.

In the above embodiment, as the protective wall 29 for protecting the second oxygen sensor 25, a member bent in an L shape in a side view is used to protect the second oxygen sensor 25 from the front and from below, but as the protective wall 29, a flat plate-shaped protective wall capable of protecting at least the second oxygen sensor 25 from the front may be used.

The application of the present invention is not limited to the above-described embodiments, and it is needless to say that various modifications can be made without departing from the scope of the invention.

Claims

1. An oxygen sensor arrangement structure for a motorcycle in which a catalyst (14) is provided in an exhaust pipe (13) extending from an engine (12), and an oxygen sensor (25) is attached to the exhaust pipe (13) on the downstream side of the catalyst (14),

the oxygen sensor (25) is disposed on the vehicle width direction inner side of the exhaust pipe (13) and at a position overlapping the engine (12) in a plan view,

a protective wall (29) for protecting the oxygen sensor (25) is attached to the exhaust pipe (13) in front of the oxygen sensor (25).

2. The oxygen sensor arrangement structure for a motorcycle according to claim 1,

the protective wall (29) has a curved shape.

3. The oxygen sensor arrangement structure of a motorcycle according to claim 1 or 2,

a sensor boss (28) is attached to the exhaust pipe (13) from the exhaust pipe (13) toward the inside in the vehicle width direction, the sensor boss (28) is disposed at a position overlapping the engine (12) in a plan view, and the oxygen sensor (25) is attached to the sensor boss (28).

4. The oxygen sensor arrangement structure for a motorcycle according to any one of claims 1 to 3,

a cover member (26) that covers the outside of the exhaust pipe (13) is attached to the exhaust pipe (13), and the cover member (26) is disposed at a position that overlaps the oxygen sensor (25) in a side view.

5. The oxygen sensor arrangement structure for a motorcycle according to claim 4,

the cover member (26) is attached to the exhaust pipe (13) at two front and rear positions thereof via attachment portions (26a), and the oxygen sensor (25) is disposed between the attachment portions (26a) in the front-rear direction.

6. The oxygen sensor arrangement structure for a motorcycle according to any one of claims 1 to 5,

the oxygen sensor (25) is disposed on the inside of the brake pedal (23) in the vehicle width direction.

7. The oxygen sensor arrangement structure for a motorcycle according to any one of claims 1 to 6,

the catalyst (14) is disposed in front of the engine (12) in a side view, and the oxygen sensor (25) is disposed below the engine (12).

8. The oxygen sensor arrangement structure for a motorcycle according to any one of claims 1 to 7,

the oxygen sensor (25) is disposed on the innermost side of the exhaust pipe (13) in a plan view.

9. The oxygen sensor arrangement structure for a motorcycle according to any one of claims 1 to 8,

an angle (alpha) formed by the central axis (l) of the oxygen sensor (25) and a horizontal plane (H) is 45 degrees or less.