exhaust system

Abstract

To provide an exhaust device capable of maintaining detection accuracy of exhaust gas components while an exhaust gas sensor is disposed in the vicinity of a communication passage that couples right and left exhaust pipes to each other.SOLUTION: An exhaust device (30) includes: a pair of right and left exhaust pipes (T) mounted to a power unit (P) of a vehicle (1) and extending rearward; and a communication passage (35) extending in a vehicle width direction to connect the exhaust pipes (T) to each other. The communication passage (35) is provided on the downstream side in a flow passage direction of exhaust gas (G) of the power unit (P) relative to catalyst devices (C) accommodated in each of the right and left exhaust pipes (T). An exhaust gas sensor (42) for detecting components of the exhaust gas (G) of the power unit (P) is disposed in the exhaust pipe (T) between the catalyst device (C) and the communication passage (35). The exhaust gas sensor (42) is mounted to a position nearer to the vehicle width direction inner side of the exhaust pipe (T), and is disposed so as not to superpose on the communication passage (35) wholly in the vehicle rear face view.SELECTED DRAWING: Figure 4

Description

[Technical Field]

[0001] The present invention relates to an exhaust system, and more particularly to an exhaust system in which a catalytic converter is disposed inside each of a pair of left and right exhaust pipes. [Background technology]

[0002] 2. Description of the Related Art Conventionally, an exhaust system has been known in which a catalytic device is disposed inside each of a pair of left and right exhaust pipes.

[0003] Patent Document 1 discloses an exhaust system in which a catalytic device is disposed inside each of a pair of left and right exhaust pipes, a communication passage is provided connecting the left and right exhaust pipes, and an exhaust gas sensor that detects the components of the exhaust gas is attached near the connection between the exhaust pipes and the communication passage. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-156330 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the exhaust device of Patent Document 1, the exhaust gas sensor is installed near the connection between the exhaust pipe and the connecting passage, so exhaust gas flowing back from the connecting passage could come into contact with the exhaust gas sensor, which could affect the accuracy of detecting the components of the exhaust gas.

[0006] The object of the present invention is to solve the problems of the above-mentioned conventional technology and to provide an exhaust system that can maintain the accuracy of detecting exhaust gas components while arranging an exhaust gas sensor near the connecting passage that connects the left and right exhaust pipes. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides an exhaust system (30) including a pair of left and right exhaust pipes (T) attached to a power unit (P) of a vehicle (1) and extending rearward, and a communication passage (35) extending in the vehicle width direction and connecting the exhaust pipes (T), wherein the communication passage (35) is provided downstream in the flow direction of exhaust gas (G) from the power unit (P) with respect to catalytic devices (C) housed on the left and right sides of the exhaust pipes (T), and an exhaust gas sensor (42) for detecting components of the exhaust gas (G) is disposed in the exhaust pipe (T) at a position between the catalytic devices (C) and the communication passage (35).

[0008] A second feature is that the exhaust gas sensor (42) is attached to the exhaust pipe (T) at a position closer to the inside in the vehicle width direction, and is arranged so as not to overlap the entirety of the communication passage (35) when viewed from the rear of the vehicle.

[0009] A third feature is that the connection portion (41) between the exhaust pipe (T) and the communication passage (35) is provided on the outer side in the vehicle width direction than the attachment portion (36) of the exhaust gas sensor (42).

[0010] Furthermore, an engagement portion (38) that engages with a muffler (M) that silences the exhaust gas (G) is provided behind the communication passage (35), and a fourth feature is that the distance (B) from the connection portion (41) to the engagement portion (38) is longer than the distance (A) from the connection portion (41) to the mounting portion (36). [Effects of the Invention]

[0011] According to a first feature, an exhaust system (30) includes a pair of left and right exhaust pipes (T) attached to a power unit (P) of a vehicle (1) and extending rearward, and a communication passage (35) extending in the vehicle width direction and connecting the exhaust pipes (T), the communication passage (35) is provided downstream of catalytic converters (C) housed on the left and right sides of the exhaust pipes (T) in the flow direction of exhaust gas (G) from the power unit (P), and an exhaust gas sensor (42) for detecting components of the exhaust gas (G) is disposed in the exhaust pipe (T) between the catalytic converters (C) and the communication passage (35). This allows the exhaust gas sensor to detect components of the exhaust gas after passing through the catalytic converter, and prevents exhaust gas flowing back from the communication passage from coming into contact with the exhaust gas sensor. This makes it possible to maintain the detection accuracy of the exhaust gas sensor.

[0012] According to the second feature, the exhaust gas sensor (42) is attached to the exhaust pipe (T) at a position closer to the inside in the vehicle width direction, and is arranged so as not to overlap the entirety of the connecting passage (35) when viewed from the rear of the vehicle. This makes it difficult to see the exhaust gas sensor from the outside, improving the appearance of the vehicle, and also making it possible to prevent the exhaust gas sensor and the connecting passage from interfering with each other when attaching and detaching them, thereby improving maintainability.

[0013] According to the third feature, the connection portion (41) between the exhaust pipe (T) and the communication passage (35) is provided on the outer side in the vehicle width direction than the mounting portion (36) of the exhaust gas sensor (42), so that exhaust gas flowing back from the communication passage can be prevented from coming into contact with the exhaust gas sensor.

[0014] According to the fourth feature, an engagement portion (38) that engages with a muffler (M) that silences the exhaust gas (G) is provided behind the communicating passage (35), and the distance (B) from the connecting portion (41) to the engagement portion (38) is longer than the distance (A) from the connecting portion (41) to the mounting portion (36). This makes it possible to increase the distance between the exhaust gas sensor and the muffler, and even if a drain hole is provided at a position closer to the front of the muffler, it is possible to prevent outside air entering through the drain hole from affecting the detection accuracy of the exhaust gas sensor. [Brief explanation of the drawings]

[0015] [Figure 1] 1 is a left side view of a motorcycle to which an exhaust system according to an embodiment of the present invention is applied. [Figure 2] FIG. 2 is an enlarged view of a portion of FIG. [Figure 3] FIG. [Figure 4] FIG. 4 is a partially enlarged view of FIG. 3. [Figure 5] FIG. 5 is a cross-sectional view taken along line VV in FIG. [Figure 6] FIG. 6 is a cross-sectional view taken along line VI-VI in FIG. 4. DETAILED DESCRIPTION OF THE INVENTION

[0016] Preferred embodiments of the present invention will now be described in detail with reference to the drawings. Fig. 1 is a left side view of a motorcycle 1 to which an exhaust device 30 according to one embodiment of the present invention is applied. Fig. 2 is a partially enlarged view of Fig. 1. Fig. 2 shows the state in which a cover member 32 that covers a portion of the exhaust device 30 has been removed. The motorcycle 1 is a straddle-type vehicle that travels by transmitting the driving force of a power unit P, which is an integrated configuration of an internal combustion engine and a transmission, to a rear wheel WR via a shaft drive mechanism (not shown).

[0017] An arm member 7, which rotatably supports the front wheels WF and constitutes a front suspension, is supported so as to be movable up and down at the front ends of a pair of left and right main frames F1 that constitute the body frame F. In front of a steering handle 2 that steers the arm member 7, a front cowl 6 is disposed that supports a windscreen 4, a pair of left and right rearview mirrors 3, and a headlight 5.

[0018] A pivot frame F2 supporting a pivot 9 that pivotally supports a swing arm (not shown) for swinging is connected to the rear of the main frame F1, which extends rearward and downward. A rear wheel WR is pivotally supported at the rear end of the swing arm for free rotation. A fuel tank 14 extending below the seat 13 is disposed above the main frame F1, and a rear cowl 11 supporting a taillight device 10 is disposed behind the seat 13. A pair of left and right pannier cases 12 are provided below the rear cowl 11.

[0019] A power unit P including a horizontally opposed six-cylinder internal combustion engine is suspended from a main frame F1. An exhaust system 30 having a pair of left and right mufflers M (ML, MR) is attached to the power unit P. The exhaust system 30 comprises six cylinder connecting pipes 31, a collecting pipe 33 connected to the rear of the cylinder connecting pipes 31, a catalyst housing section 34 connected to the rear of the collecting pipe 33, a curved pipe 40 connected to the rear of the catalyst housing section 34, a muffler M connected to the rear of the curved pipe 40, and a communication passage 35 oriented in the vehicle width direction and connecting the left and right curved pipes 40. The rear ends of the curved pipes 40 and the front ends of the mufflers M are connected by an engaging band 38 as an engaging section.

[0020] FIG. 3 is a plan view of the exhaust device 30. FIG. 4 is a partially enlarged view of FIG. 3, and FIG. 5 is a cross-sectional view taken along line VV in FIG. 4. The same reference numerals as those used above indicate the same or equivalent parts. As described above, the exhaust pipe T of the exhaust device 30 is composed of the cylinder connecting pipe 31, the collecting pipe 33, the catalyst housing 34, the curved pipe 40, and the communication passage 35. The mounting portions 36 (36L, 36R) of the exhaust gas sensor 42 that detects the components of the exhaust gas G are provided on the inner side of the curved pipe 40 in the vehicle width direction. The muffler M (MR) is composed of an outer shell member 48 that houses an inlet member 44, a first inner pipe 46, a second inner pipe 47 supported by a partition wall 45, and the like. A drain hole 50 is formed in the lower part of the outer shell member 48 near the front.

[0021] The exhaust system 30 according to this embodiment is characterized in that the communication passages 35 are provided rearward of the catalytic converters C housed on the left and right sides of the exhaust pipe T, and the exhaust gas sensor 42 is disposed in the exhaust pipe T at a position between the catalytic converters C and the communication passages 35. This allows the exhaust gas sensor 42 to detect the components of the exhaust gas G after it has passed through the catalytic converters C, and prevents the exhaust gas G flowing back from the communication passages 35 from coming into contact with the exhaust gas sensor 42, thereby maintaining the detection accuracy of the exhaust gas sensor 42.

[0022] The curved pipe 40 and the communication passage 35 are connected at a connection portion 41. A fastening band 39 is attached to the left side of the communication passage 35. This embodiment is characterized in that the connection portion 41 between the curved pipe 40 and the communication passage 35 is located outside the mounting portions 36 (36L, 36R) of the exhaust gas sensor 42 in the vehicle width direction. This prevents exhaust gas G flowing back from the communication passage 35 from coming into contact with the exhaust gas sensor 42.

[0023] Furthermore, this embodiment is characterized in that the distance B from the connecting portion 41 to the engaging portion 38 is longer than the distance A from the connecting portion 41 to the mounting portion 36 (36L, 36R). This makes it possible to increase the distance between the exhaust gas sensor 42 and the muffler M, preventing outside air entering through the drain hole 50 from affecting the detection accuracy of the exhaust gas sensor 42.

[0024] Figure 6 is a cross-sectional view taken along line VI-VI in Figure 4. The same reference numerals as those used above indicate the same or equivalent parts. This figure shows the exhaust device 30 attached to the motorcycle 1. A shaft drive mechanism 16 is disposed inside a swing arm 15 that rotatably supports the rear wheel WR. A connecting portion 41 provided in the curved pipe 40 is shaped to be inclined downward so that the straight portion of the communication passage 35 is disposed downward to avoid the swing arm 15, which swings up and down.

[0025] The exhaust gas sensor 42 is attached to a position closer to the inside of the curved pipe 40 in the vehicle width direction, and is arranged so that it does not entirely overlap with the communication passage 35 when viewed from the rear of the vehicle. This makes the exhaust gas sensor 42 less visible from the outside, improving the appearance of the motorcycle 1, and also making it easier to maintain by preventing the exhaust gas sensor 42 and the communication passage 35 from interfering with each other when attaching or detaching them.

[0026] As described above, the exhaust system 30 according to the present invention includes a pair of exhaust pipes T attached to the power unit P of the motorcycle 1 and extending rearward, and a communication passage 35 extending in the vehicle width direction and connecting the exhaust pipes T, in which the communication passage 35 is provided downstream of the catalytic converters C housed on the left and right sides of the exhaust pipes T in the flow direction of exhaust gas G from the power unit P, and an exhaust gas sensor 42 that detects the components of exhaust gas G is disposed in the exhaust pipe T between the catalytic converters C and the communication passage 35. This allows the exhaust gas sensor 42 to detect the components of exhaust gas G after passing through the catalytic converters C, and prevents exhaust gas G flowing back from the communication passage 35 from coming into contact with the exhaust gas sensor 42. This makes it possible to maintain the detection accuracy of the exhaust gas sensor 42.

[0027] The configuration of the motorcycle, the configuration and number of cylinders of the internal combustion engine, the shape and structure of the exhaust system, the position and number of catalytic converters, the shape and structure of the outer shell and partition walls that make up the muffler, the material and shape of each pipe member, the shape and structure of the exhaust gas sensor, the position of the exhaust gas sensor, the position of the drain hole, etc. are not limited to the above-described embodiments and can be modified in various ways. The exhaust system according to the present invention is not limited to motorcycles, but can also be applied to various vehicles that use a power unit including an internal combustion engine as a drive source, such as three-wheeled vehicles and four-wheeled vehicles. [Explanation of symbols]

[0028] 1...motorcycle (vehicle), 30...exhaust system, 35...communicating passage, 36 (36L, 36R)...mounting portion, 38...engagement portion, 41...connection portion, 42...exhaust gas sensor, P...power unit, T...exhaust pipe, C...catalytic device, G...exhaust gas, M (ML, MR)...muffler, A...distance from connection portion to mounting portion, B...distance from connection portion to engagement portion

Claims

1. An exhaust system (30) including a pair of left and right exhaust pipes (T) attached to a power unit (P) of a vehicle (1) and extending rearward, and a communication passage (35) extending in the vehicle width direction and connecting the exhaust pipes (T), the communication passage (35) is provided downstream of catalytic converters (C) housed on the left and right sides of the exhaust pipe (T) in a flow direction of exhaust gas (G) from the power unit (P), an exhaust gas sensor (42) for detecting components of the exhaust gas (G) is disposed in the exhaust pipe (T) at a position between the catalytic device (C) and the communication passage (35); The exhaust gas sensor (42) is attached to the exhaust pipe (T) at a position closer to the inside of the vehicle width direction, and is arranged so as not to overlap the entirety of the exhaust gas sensor (42) with the communication passage (35) when viewed from the rear of the vehicle.

2. 2. The exhaust system according to claim 1, wherein a connection portion (41) between the exhaust pipe (T) and the communication passage (35) is provided on the outer side in the vehicle width direction than a mounting portion (36) of the exhaust gas sensor (42).

3. an engaging portion (38) that engages with a muffler (M) that silences the exhaust gas (G) is provided behind the communication passage (35); 3. The exhaust device according to claim 2, wherein a distance (B) from the connecting portion (41) to the engaging portion (38) is longer than a distance (A) from the connecting portion (41) to the mounting portion (36).

4. An exhaust device as described in Claim 2, characterized in that the mounting portion (36) is arranged in a recess provided in the exhaust pipe (T).

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