JP2021042678A - Exhaust device for saddle-ride type vehicle - Google Patents

Abstract

To provide an exhaust device for a saddle-ride type vehicle which enables compact arrangement while securing the length of an exhaust passage.SOLUTION: An exhaust device 35 of a two-cylinder engine E mounted on a saddle-ride type vehicle includes an exhaust pipe 24 extending downward in front of the engine E from an exhaust port 20a of each of cylinders, a collecting pipe 26 in which the exhaust pipes 24 are collected, a catalyst pipe 30 which is arranged in the downstream side of the collecting pipe 26 and in which a catalyst converter 28 is stored, and a muffler 34 which is located in the downstream side of the catalyst pipe 30. The catalyst pipe 30 has a front end 30a connected to a downstream end 26b of the collecting pipe 26, is extended in a longitudinal direction of the vehicle, and has a rear end 30b connected to the muffler 34. The muffler 34 is formed to have the longitudinal dimension and the vehicle width dimension larger than those of the catalyst pipe 30, and muffles exhaust G. Downstream ends 24b of the two exhaust pipes 24 are aligned in the longitudinal direction.SELECTED DRAWING: Figure 1

Description

The present invention relates to an exhaust device for a two-cylinder engine mounted on a saddle-mounted vehicle.

In a saddle-mounted vehicle such as a motorcycle, there is a muffler that silences the exhaust gas and contains a catalytic converter that purifies the exhaust gas (for example, Patent Document 1). In such a vehicle, the exhaust device can be compactly configured and arranged.

Japanese Patent No. 4267690

However, in Patent Document 1, the muffler becomes large and its structure becomes complicated, and the degree of freedom in design tends to be limited. If the catalytic converter is extended to the upstream side outside the muffler, the structure of the muffler will be simplified, but the collecting pipe on the upstream side of the catalytic converter needs a certain length to sufficiently mix the exhaust gas, so it will be assembled. The length of the exhaust passage from the inlet of the pipe to the muffler via the catalytic converter becomes large, which makes it difficult to arrange the exhaust device compactly.

An object of the present invention is to provide an exhaust device for a saddle-type vehicle that can be arranged compactly while ensuring the length of the exhaust passage.

In order to achieve the above object, the exhaust device of the saddle-type vehicle of the present invention is an exhaust device of a two-cylinder engine mounted on the saddle-type vehicle, and the front of the engine is downward from the exhaust port of each cylinder. It is provided with an exhaust pipe extending to, a collecting pipe in which the exhaust pipes are gathered, a catalyst pipe arranged on the downstream side of the collecting pipe and accommodating a catalyst converter, and a muffler arranged on the downstream side of the catalyst pipe. ing. The catalytic converter purifies the exhaust, and the muffler silences the exhaust. The front end of the catalyst pipe is connected to the downstream end of the collecting pipe, extends in the front-rear direction of the vehicle, and the rear end is connected to the muffler. The muffler is formed so that its front-rear direction dimension and vehicle width direction dimension are larger than those of the catalyst tube. The downstream ends of the two exhaust pipes are lined up in the front-rear direction. Here, "upstream" and "downstream" mean upstream and downstream in the exhaust flow direction.

According to this configuration, since the catalytic converter is arranged outside the muffler, the structure of the muffler is simplified and the muffler can be miniaturized. Further, the downstream ends of the two exhaust pipes are arranged side by side in the front-rear direction and connected to the collecting pipe. By arranging the downstream ends of the two exhaust pipes side by side in the front-rear direction, the space in front of the engine can be effectively used and the length of the exhaust pipes can be secured. Further, since the downstream ends of the two exhaust pipes are arranged side by side in the front-rear direction and connected to the collecting pipe, the upstream ends of the collecting pipes open substantially upward. Therefore, it is possible to increase the length of the exhaust passage in the collecting pipe while suppressing the increase in the front-rear dimension of the collecting pipe. As a result, the exhaust gas can be sufficiently mixed in the collecting pipe. As described above, according to the present invention, the exhaust device can be arranged compactly while increasing the length of the exhaust passage.

In the present invention, even if the collecting pipe has a curved portion that is curved so as to protrude forward and diagonally downward from the front upper entrance to the rear lower portion, and a straight portion that extends straight rearward from the curved portion. Good. In this case, the downstream end of the exhaust pipe may be located in front of the upstream end. According to this configuration, the collecting pipe has a substantially L-shape when viewed from the side, so that the length of the exhaust passage can be increased without squeezing the space in front of the engine.

When the collecting pipe has the curved portion and the straight portion, the rear portion of the straight portion of the collecting pipe may bulge downward. According to this configuration, it is possible to suppress the bias of the exhaust flow that tends to concentrate on the lower part in the straight portion by passing through the curved portion of the collecting pipe. As a result, the exhaust gas is effectively purified by the catalytic converter.

When the rear portion of the straight portion of the collecting pipe bulges downward, an exhaust gas sensor for detecting a specific component in the exhaust gas is provided in the front portion in front of the bulging rear portion in the straight portion of the collecting pipe. May be. According to this configuration, since the exhaust gas sensor is attached to the region where the passage area before swelling in the collecting pipe is small, it is possible to accurately sense the exhaust gas in a state where it is not diffused within a small cross-sectional area.

When the exhaust gas sensor is provided, a connecting pipe to which an additional exhaust gas sensor can be attached may be arranged between the catalyst pipe and the muffler. According to this configuration, deterioration of the catalytic converter can be detected when an additional exhaust gas sensor is attached. This makes it possible to grasp the replacement time of the catalytic converter.

When the exhaust gas sensor is provided, the collecting pipe is configured by joining two pipe halves divided into left and right at two joints along the flow direction of the exhaust, and the left and right pipe halves. The joint portion in the above is overlapped in the radial direction of the collecting pipe and extends in the front-rear direction, and the exhaust gas sensor is attached near one joint portion of the two joint portions in one pipe half body. , The one joint portion of the pipe half body to which the exhaust gas sensor is attached may be superposed on the radial outer side of the corresponding joint portion of the other pipe half body. Here, "left and right" means the width direction of the vehicle body. According to this configuration, it is possible to make it difficult for the influence of welding strain between the pipe halves to be applied to the mounting portion of the exhaust gas sensor.

In the present invention, the muffler may be arranged below the engine. In a vehicle where the muffler is placed below the engine, the exhaust passage from the engine to the muffler tends to be short, but the layout of the exhaust pipe and collecting pipe described above ensures a long exhaust passage length and the exhaust device is arranged compactly. can do.

According to the exhaust device of the saddle-type vehicle of the present invention, the exhaust device can be arranged compactly while gaining the length of the exhaust passage.

It is a side view which shows the main part of the motorcycle which is a kind of saddle-type vehicle provided with the exhaust device which concerns on 1st Embodiment of this invention. It is a front view of the exhaust system. It is a top view of the exhaust system. It is sectional drawing along the IV-IV line of FIG. It is sectional drawing along the VV line of FIG. It is a side view which shows the modification of the exhaust device.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. In the present specification, the "left side" and "right side" mean the "left side" and "right side" as seen by the driver in the state of being in the vehicle. Further, "upstream" and "downstream" mean upstream and downstream in the exhaust flow direction.

FIG. 1 is a side view of a motorcycle, which is a kind of saddle-type vehicle provided with an exhaust device according to an embodiment of the present invention. In FIG. 1, the body frame FR of the motorcycle of the present embodiment has a main frame 1 constituting the front half portion and a rear frame 2 constituting the rear half portion. The rear frame 2 is connected to the rear portion of the main frame 1.

A front fork 6 is rotatably supported by a head pipe 4 at the front end of the main frame 1 via a steering shaft (not shown). A front wheel 8 is attached to the lower end of the front fork 6. A handle 10 is attached to the upper end of the front fork 6.

A swing arm bracket 12 is provided at the rear end of the main frame 1. The front end of the swing arm 13 is supported on the swing arm bracket 12 so as to swing up and down around the pivot shaft 14. A rear wheel (not shown) is attached to the rear end of the swing arm 13.

The engine E, which is a drive source, is attached below the main frame 1 and in front of the swing arm bracket 12. The engine E drives the rear wheels (not shown) via a power transmission member (not shown) such as a chain.

The engine E of the present embodiment is a two-cylinder engine. The 4-cycle engine E has a crankcase 16 that rotatably supports a crankshaft (not shown), a cylinder 18 that projects upward from the crankcase 16, and a cylinder head 20 that is attached to the upper part of the cylinder 18. doing. Further, an oil pan 21 is provided below the crankcase 16, and an oil filter 22 is provided on the front surface of the lower portion of the crankcase 16. The oil filter 22 projects forward from the front surface of the crankcase 16. When the engine E is started, the oil in the oil pan 21 is sucked up by the oil pump 23, filtered by the oil filter 22, and then supplied to each part.

An exhaust port 20a is formed on the front surface of the cylinder head 20, and an intake port 20b is formed on the rear surface. Two exhaust ports 20a and one intake port 20b are provided for each cylinder, for a total of two. An intake system device is connected to each intake port 20b. The intake system equipment supplies external air to the engine E as intake air.

One exhaust pipe 24 is connected to each exhaust port 20a. That is, in this embodiment, there are two exhaust pipes 24. Each exhaust pipe 24 extends downward in front of the engine E and then is assembled by a collecting pipe 26 in front of and below the engine E. In the collecting pipe 26, the two exhaust pipes 24 merge to form a single exhaust passage EP.

A catalyst tube 30 in which the catalyst converter 28 is housed is arranged on the downstream side of the collecting pipe 26. The catalyst converter 28 is, for example, a honeycomb catalyst. However, the catalytic converter 28 is not limited to this. In the present embodiment, two catalyst converters 28 are arranged side by side in the front-rear direction in the catalyst tube 30. When passing through the catalyst tube 30, the catalyst converter 28 purifies the exhaust gas G.

A muffler 34 is connected to the downstream side of the catalyst tube 30 via a connecting tube 32. The muffler 34 of the present embodiment is an inflatable muffler having a plurality of expansion chambers inside. However, the format of the muffler 34 is not limited to this. When passing through the muffler 34, the exhaust G is muted in the muffler 34. The exhaust G is muted in the muffler 34 and then discharged to the outside. The exhaust device 35 of the engine E is composed of the exhaust pipe 24, the collecting pipe 26, the catalyst pipe 30, the connecting pipe 32, and the muffler 34. Each of these pipes 24, 26, 30, 32 and muffler 34 is joined by welding to form an exhaust passage.

The exhaust gas sensor 36 is provided in the collecting pipe 30. That is, the exhaust gas sensor 36 is arranged upstream of the catalytic converter 28. The exhaust gas sensor 36 detects a specific component in the exhaust gas. The exhaust gas sensor 36 is, for example, an oxygen concentration sensor. In this embodiment, the exhaust gas sensor 36 is used to adjust the fuel concentration. The exhaust gas sensor 36 is attached to a mounting seat 37 formed on the collecting pipe 30.

A sensor guard 38 is provided in front of the exhaust gas sensor 36 in the collecting pipe 30. The sensor guard 38 is formed so as to cover the exhaust gas sensor 36 from the front, and protects the exhaust gas sensor 36 from muddy water, pebbles, and the like during traveling. The sensor guard 38 is made of, for example, a plate material, and is fixed to the collecting pipe 30 by welding. However, the structure of the sensor guard 38 is not limited to this. The sensor guard 38 may not be provided.

In the present embodiment, the front half (upstream side portion) of the exhaust pipe 24 and the collecting pipe 26 is arranged in front of the engine E. The latter half (downstream side portion) of the collecting pipe 26 and the catalyst pipe 30 are arranged below the crankcase 16 of the engine E. The muffler 34 is arranged at the lower part of the vehicle body. Specifically, the muffler 34 is located below the crankcase 16 of the engine E and below the swing arm bracket 12.

The front part of the vehicle body, specifically, the front part of the engine E and the area in front of the engine E are covered from the outside by a resin cowling 40. More specifically, the cowling 40 also covers the front half (upstream side portion) of the exhaust pipe 24 and the collecting pipe 26 from the outside.

Hereinafter, the exhaust device 35 of the present embodiment will be described in detail with reference to FIGS. 1 to 5. In addition, in FIGS. 2 and 3, the sensor guard 38 is omitted.

As shown in FIG. 1, the upstream end 24a of the exhaust pipe 24 is connected to the exhaust port 20a of the engine E, and the downstream end 24b is connected to the upstream end 26a of the collecting pipe 26. The downstream end 24b of the exhaust pipe 24 is located in front of the upstream end 24a. That is, the exhaust pipe 24 extends downward while being slightly inclined forward. Here, the upstream end portion 24a of the exhaust pipe 24 is a portion connected to the flange 24c at the outlet of the exhaust port 20a, and the downstream end portion 24b of the exhaust pipe 24 is a portion connected to the upstream end portion 26a of the collecting pipe 26. .. The upstream end edge 24aa of the exhaust pipe 24 enters the inside of the exhaust port 20a, and the downstream end edge 24ba of the exhaust pipe 24 enters the inside of the upstream end portion 26a of the collecting pipe 26.

The downstream end portions 24b of the two exhaust pipes 24 are arranged in the front-rear direction. In the present embodiment, the downstream end portion 24b of the exhaust pipe 24 is located in front of the oil filter 22 and inside the cowling 40. In the present embodiment, the exhaust pipe 24-1 of the first cylinder is located in front of the exhaust pipe 24-2 of the second cylinder. As shown in FIG. 2, each exhaust pipe 24 extends downward while being curved in the left-right direction.

As shown in FIG. 1, the upstream end 26a of the collecting pipe 26 is connected to the downstream end 24b of the exhaust pipe 24, and the downstream end 26b is connected to the upstream end (front end) 30a of the catalyst pipe 30. .. The collecting pipe 26 has a curved portion 42 forming the first half portion (upstream portion) and a straight portion 44 forming the second half portion (downstream portion).

The curved portion 42 is curved so as to protrude forward diagonally downward P from the front upper entrance 26c toward the rear lower part. The straight portion 44 extends straight rearward from the curved portion 42. That is, the collecting pipe 26 has a substantially L-shape when viewed from the side. The rear portion of the straight portion 44 of the collecting pipe 26 bulges downward. In other words, a bulging portion 45 that bulges downward is formed at the rear portion of the straight portion 44. The passage area of the bulging portion 45 gradually increases from the front end (upstream end) to the rear end (downstream end). The exhaust gas sensor 36 is provided in a region in front of the bulging portion 45 in the straight portion 44 of the collecting pipe 26.

As shown in FIG. 3, the collecting pipe 26 has a left side pipe half body 46L and a right side pipe half body 46R divided into two left and right. These two pipe halves 46L and 46R are joined by welding, for example, at two upper and lower joints 48 along the flow direction of the exhaust gas G. As shown in FIG. 4, the joint portion 48 is polymerized in the radial direction of the collecting pipe 26 and extends in the front-rear direction.

The two joints 48 are arranged substantially in the front-rear direction at the curved portion 42, and are arranged in the vertical direction at the straight portion 44 as shown in FIG. In the present embodiment, the mounting seat 37 of the exhaust gas sensor 36 is mounted near one of the two joints 48 in one pipe half (left pipe half 46L). Specifically, the mounting seat 37 is mounted closer to the upper joint 48 in the left pipe half body 46L. The screw portion 36a of the exhaust gas sensor 36 is screwed into the screw hole 37a provided in the mounting seat 37.

The upper joint 48L of the left side pipe half body 46L to which the exhaust gas sensor 36 is attached is polymerized on the radial outer side (upper side) of the upper joint portion 48R of the right side pipe half body 46R. In other words, the upper joint 48L of the left side pipe half body 46L provided with the mounting seat 37 of the exhaust gas sensor 36 is polymerized on the radial outer side of the upper joint portion 48R of the right side pipe half body 46R. Since the welded portion W is the side edge of the joint portion 48L, it is far from the mounting seat 37, so that the mounting seat 37 is less susceptible to welding strain. In the present embodiment, the lower joint portion 48L of the left side pipe half body 46L is also polymerized on the radial outer side (lower side) of the lower joint portion 48R of the right side pipe half body 46R.

The mounting seat 37 of the exhaust gas sensor 36 is formed so as not to overlap the joint portion 48. Specifically, as shown in FIG. 4, in the vicinity of the mounting seat 37 of the exhaust gas sensor 36, the joint portion 48 is curved in the circumferential direction of the collecting pipe 26 so as to bypass the mounting seat 37.

As shown in FIG. 3, the upstream end (front end) 30a of the catalyst pipe 30 is connected to the downstream end 26b of the collecting pipe 26, extends in the front-rear direction of the vehicle, and the downstream end (rear end) 30b is connected. It is connected to the muffler 34 via a pipe 32. The muffler 34 is formed such that the front-rear direction dimension L1 and the vehicle width direction dimension W1 are larger than the front-rear direction dimension L2 and the vehicle width direction dimension W2 of the catalyst tube 30 (L1> L2, W1> W2).

As shown in the modified example of FIG. 6, the connecting pipe 32 may be provided with a mounting seat 52 for mounting an additional exhaust gas sensor 50. The additional exhaust gas sensor 50 detects a specific component in the exhaust gas. The additional exhaust gas sensor 50 is, for example, an oxygen concentration sensor. An additional exhaust gas sensor 50 is located downstream of the catalytic converter 28 and is used to detect deterioration of the catalytic converter 28. This makes it possible to grasp the replacement time of the catalytic converter 28.

Next, the operation of the exhaust device 35 of the present embodiment will be described. When the engine E of FIG. 1 is started, the exhaust G of the engine E flows into the exhaust pipe 24 from the exhaust port 20a of the cylinder head 20. The exhaust G that has flowed into the exhaust pipe 24 merges with the collecting pipe 26 and then flows into the catalyst pipe 30. The exhaust G is purified by the catalyst converter 28 while flowing through the catalyst tube 30. The exhaust G purified by the catalytic converter 28 flows into the muffler 34, is muted in the muffler 34, and then is discharged to the outside.

In the above configuration, since the catalytic converter 28 is arranged outside the muffler 34, the structure of the muffler 34 can be simplified and the muffler 34 can be miniaturized. Further, since the catalyst converter 28 is taken out of the muffler 34, an additional exhaust gas sensor 50 can be attached to the downstream side of the catalyst converter 28 shown in FIG.

As shown in FIG. 1, by arranging the catalyst converter 28 in front of the muffler 34, there is a concern that the exhaust pipe 24 and the collecting pipe 26 on the upstream side of the catalyst pipe 30 may press the space in front of the engine E. Specifically, it is necessary to prevent the exhaust pipe 24 and the collecting pipe 26 from interfering with the cowling 40, the front wheel 8, and the like. Further, it is necessary to secure the lengths of the exhaust pipe 24 and the collecting pipe 26 while avoiding interference with them. Specifically, unless the lengths of the exhaust pipe 24 and the collecting pipe 26 are to some extent, the exhaust G is not sufficiently mixed by the time it comes into contact with the exhaust gas sensor 36 and the catalytic converter 28.

As shown in FIG. 2, the exhaust pipe 24 extends downward while being curved in the left-right direction. As a result, the length of the exhaust pipe 28 can be increased. Further, the downstream end portions 24b of the two exhaust pipes 24 are arranged side by side in the front-rear direction and connected to the collecting pipe 26. By arranging the two exhaust pipes 24 side by side in the front-rear direction, it is possible to secure the length of the exhaust pipe 24 by effectively utilizing the space in front of the engine E while preventing interference with the cowling 40. As shown in FIG. 1, the exhaust pipe 24 is greatly bent in the front-rear direction, and the downstream end portion 24b of the exhaust pipe 24 is located in front of the upstream end portion 24a.

Further, since the two exhaust pipes 24 are connected to the collecting pipe 26 side by side in the front-rear direction, the inlet 26c of the collecting pipe 26 opens substantially upward. Therefore, the length of the collecting pipe 26 can be secured while suppressing the increase in the front-rear dimension of the collecting pipe 26. Specifically, when the exhaust pipes 24 are arranged in the vertical direction and connected to the collecting pipe 26, the inlet 26c of the collecting pipe 26 opens forward. Therefore, if an attempt is made to secure the same length of the collecting pipe 26 as in the present embodiment, the length of the collecting pipe 26 in the front-rear direction becomes large, and the exhaust pipe 24 and the collecting pipe 26 may interfere with the cowling 40.

By arranging the downstream end portions 24b of the exhaust pipe 24 in the front-rear direction and connecting them to the collecting pipe 26 as in the above configuration, the length of the collecting pipe 26 is secured while avoiding interference with the cowling 40, and the collecting pipe is secured. Exhaust G can be sufficiently mixed in 26. As a result, the detection accuracy of the exhaust gas sensor 36 is improved. Further, by attaching the exhaust gas sensor 36 to the collecting pipe 26, it is not necessary to separately provide a pipe dedicated to detection, and it is easy to reduce the size of the exhaust device 35.

As shown in FIG. 2, the cowling 40 has a smaller distance in the vehicle width direction toward the lower side. Therefore, there is little space on the lower side in the width direction. Therefore, when the exhaust pipes 24 are arranged side by side in the left-right direction and connected to the collecting pipe 26, they easily interfere with the cowling 40. Further, it is necessary to consider the influence on the bank angle, and there is a restriction that the downstream end portions 24b of the exhaust pipe 24 are arranged in the left-right direction. From such a surface, the advantage of arranging the downstream end portions 24b of the exhaust pipe 24 in the front-rear direction is great.

The engine E of the present embodiment is an engine of non-equidistant explosions. Specifically, the interval from the explosion of the first cylinder to the explosion of the second cylinder is short, and the interval from the explosion of the second cylinder to the explosion of the first cylinder is long. In the present embodiment, as shown in FIG. 1, the exhaust pipe 24-1 of the first cylinder is connected to the collecting pipe 26 in a state of being arranged in front of the exhaust pipe 24-2 of the second cylinder. As a result, the flow of the exhaust gas G from the exhaust pipe 24-1 of the first cylinder is hit against the flow of the exhaust gas G from the exhaust pipe 24-2 of the second cylinder to be uniformly mixed.

In this embodiment, the muffler 34 is arranged below the engine E. In a vehicle in which the muffler 34 is arranged below the engine E, the length of the exhaust passage from the engine E to the muffler 34 tends to be short, but the exhaust passage length is sufficient due to the configuration of the exhaust pipe 24 and the collecting pipe 26 described above. Therefore, the catalyst tube 30 and the muffler 34 can be compactly arranged below the engine E. As described above, according to the above configuration, the exhaust device 35 can be arranged compactly while increasing the length of the exhaust passage.

Further, the collecting pipe 26 has a curved portion 42 that is curved so as to protrude forward and diagonally downward P from the inlet 26c toward the rear lower side, and a straight portion 44 that extends straight rearward from the curved portion 42. In this way, by forming the collecting pipe 26 in a substantially L-shape when viewed from the side, the length of the exhaust passage can be increased without squeezing the space in front of the engine E.

Further, a bulging portion 45 that bulges downward is formed at the rear portion of the straight portion 44 of the collecting pipe 26. By providing such a bulging portion 45, it is possible to suppress the bias of the flow of the exhaust G that tends to concentrate on the lower part in the straight portion 44 by passing through the curved portion 42 of the collecting pipe 26, and also to be large. It can be connected to a catalyst tube 30 having a diameter. As a result, the exhaust gas G is effectively purified by the catalytic converter 28. Also,. An exhaust gas sensor 36 is provided in front of the bulging portion 45 in the straight portion 44 of the collecting pipe 26. In this way, by attaching the exhaust gas sensor 36 to the region of the collecting pipe 26 where the passage area before swelling is small, it is possible to accurately sense the exhaust G in a state where it is not diffused within a small cross-sectional area.

As shown in FIG. 5, the mounting seat 37 of the exhaust gas sensor 36 is attached closer to the upper joint 48 of the left pipe half body 46L, and the upper joint 48L of the left pipe half body 46L is the right pipe half body 46R. It is polymerized on the radial outer side of the upper joint 48R of the above. As a result, the mounting seat 37 of the exhaust gas sensor 36 is separated from the welded portion between the pipe halves 46L and 46R, so that the mounting seat 37 is affected by the welding strain, and its position and mounting angle, that is, the angle of the screw hole 37a. It is possible to prevent an error from occurring.

The present invention is not limited to the above embodiments, and various additions, changes, or deletions can be made without departing from the gist of the present invention. For example, in the above embodiment, an example in which the exhaust device of the present invention is applied to an engine of a motorcycle has been described, but the exhaust device of the present invention is a saddle-type vehicle other than a motorcycle, for example, a tricycle, a four-wheel buggy, or the like. It can also be applied to the engine of. The exhaust device of the present invention can also be applied to a two-cycle engine. Therefore, such things are also included within the scope of the present invention.

20a Exhaust port 24 Exhaust pipe 24a Upstream end of exhaust pipe 24b Downstream end of exhaust pipe 26 Collective pipe 26a Upstream end of collecting pipe 26b Downstream end of collecting pipe 26c Inlet of collecting pipe 28 Catalytic converter 30 Catalyst pipe 30a Catalyst Front end of pipe 30b Rear end of catalyst pipe 32 Connecting pipe 34 Muffler 35 Exhaust device 36 Exhaust gas sensor 42 Curved part 44 Straight part 46L Left side pipe half body (one pipe half body)
46R Right tube half (the other tube half)
48 Joint 50 Additional exhaust gas sensor E Engine G Exhaust

Claims (8)

It is an exhaust system for a two-cylinder engine mounted on a saddle-mounted vehicle.
An exhaust pipe that extends downward from the exhaust port of each cylinder in front of the engine,
The collecting pipe where the exhaust pipes gather and
A catalyst tube arranged on the downstream side of the collecting pipe and containing a catalyst converter for purifying exhaust gas,
A muffler, which is arranged on the downstream side of the catalyst tube and silences the exhaust gas, is provided.
The front end of the catalyst pipe is connected to the downstream end of the collecting pipe, extends in the front-rear direction of the vehicle, and the rear end is connected to the muffler.
The muffler is formed so that its front-rear direction dimension and vehicle width direction dimension are larger than those of the catalyst tube.
An exhaust device for a saddle-mounted vehicle in which the downstream ends of the two exhaust pipes are lined up in the front-rear direction. In the exhaust device for a saddle-mounted vehicle according to claim 1, the collecting pipe is curved so as to protrude forward and diagonally downward from the front upper entrance toward the rear lower part, and the curved portion is straight rearward. An exhaust system for saddle-mounted vehicles that has a straight part that extends to. The exhaust device for a saddle-type vehicle according to claim 2, wherein the downstream end of the exhaust pipe is located in front of the upstream end. The exhaust device for a saddle-type vehicle according to claim 2 or 3, wherein the rear portion of the straight portion of the collecting pipe bulges downward. In the exhaust device for a saddle-mounted vehicle according to claim 4, an exhaust gas sensor provided in the front portion in front of the bulging rear portion in the straight portion of the collecting pipe to detect a specific component in the exhaust is further provided. Exhaust system for saddle-mounted vehicles. The exhaust device for a saddle-type vehicle according to claim 5, further comprising a connecting pipe arranged between the catalyst pipe and the muffler to which an additional exhaust gas sensor can be attached. .. In the exhaust device for a saddle-mounted vehicle according to claim 5 or 6, the collecting pipe is configured by joining two pipe halves divided into left and right at two joints along the flow direction of the exhaust. ,
The joints in the left and right pipe halves are polymerized in the radial direction of the collecting pipe and extend in the front-rear direction.
The exhaust gas sensor is attached near one of the two joints in one pipe half body.
The one joint portion of the pipe half body to which the exhaust gas sensor is attached is an exhaust device for a saddle-type vehicle that is polymerized on the radial outer side of the corresponding joint portion of the other pipe half body. The exhaust device for a saddle-type vehicle according to any one of claims 1 to 7, wherein the muffler is arranged below the engine.

Images