JP2577021B2 - Exhaust system for motorcycle - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exhaust system for a motorcycle that discharges exhaust gas from an engine to the rear of a vehicle, and more particularly, to a drain that is formed by condensing water vapor in exhaust gas. The present invention relates to a structure for preventing accumulation in a pipe.

[Prior Art] Exhaust gas from an engine contains a large amount of water vapor, and a part of the water vapor is discharged to the outside as vapor. As the temperature drops while flowing to the rear of the vehicle, it condenses and accumulates near the rear end of the exhaust pipe without being discharged to the outside.
In particular, in the case of a two-stroke engine, since the high gas temperature is low and the exhaust gas contains a large amount of oil, a black-brown drain mixed with oil in steam condensed water tends to accumulate. If this drain is left standing, when the engine starts running after waiting for a traffic light, when the engine is running at a high speed and under a high load, the drain will be blown out at once to the rear, which may cause a problem that the following vehicle is stained. There is.

Therefore, conventionally, a drain discharge hose is connected to the exhaust pipe so that the drain does not accumulate in the exhaust pipe, and the hose is vertically connected between the main pipe and the seat rail of the body frame. There is an exhaust device that is arranged so as to open near the pivot portion of the rear arm along the installed backstay. According to this exhaust device, since the drain hardly accumulates in the exhaust pipe, the drain does not blow out at the same time from the rear end of the exhaust pipe to the rear, so that the problem of fouling a following vehicle or the like can be solved.

[Problems to be solved by the invention]

However, in the above-described conventional exhaust device, the exhaust hose is opened near the pivot of the rear arm, so that the rear arm, the drive chain, the rear wheel, and the like are easily stained.
In the case of a motorcycle for personal use, there is a problem that the feet of rear passengers are easily stained. Further, since the discharge hose is routed along the back stay, the discharge hose is easily noticeable, and there is a problem that the appearance is deteriorated.

SUMMARY OF THE INVENTION An object of the present invention is to provide an exhaust system for a motorcycle that can prevent not only the following vehicle but also the motorcycle itself from being stained in view of the above-described problems of the conventional exhaust system, and can also suppress a reduction in appearance. .

[Means for solving the problem]

According to the present invention, the exhaust pipe 15 connected to the engine 14 is extended to the rear of the vehicle through the upper portion of the vehicle side, and a silence pipe 17 for silencing exhaust gas and discharging the exhaust gas to the rear of the vehicle is provided at the rear end of the exhaust pipe 15. In the exhaust device for a motorcycle provided with the license bracket 11, a license bracket 11 is integrally formed on a mudguard 10 that covers an upper part of the rear wheel 8, and a license support portion 11b of the license bracket 11 is provided.
Is extended downward and positioned at the rear end of the vehicle, and is formed into a substantially U-shaped cross section.
12, the direction indicator 26 is attached, and the license plate 13 is attached to the center of the rear surface of the license support portion 11b, and the muffler tube 17 is arranged to be inclined slightly upward and the rear end of the muffler tube 17 is License Support Department 11
b, a plurality of expansion chambers 21b to 21c partitioned by partitions 20a and 20b in the muffler pipe 17 are provided.
Or the lower wall of 21c and the front partition 2 of the expansion chamber 21b or 21c.
A short tube 24 bent backward is connected to the vicinity of the rear surface of 0a or 20b, and a drain discharge hose 25 is connected to the rear end of the short tube 24,
The drain discharge hose 25 is inclined rearwardly upward along the lower surface of the muffler pipe 17, extended rearward, and routed downward in the U-shape of the license support portion 11b following the extended end, A rear end opening 25a of the drain discharge hose 25 is positioned near the lower end of the license support portion 11b, and the drain discharge hose 25 is
It is characterized by being fixed to.

[Action]

The muffler pipe 17 was disposed with a slight upward inclination, and was bent rearward on the lower surface of the expansion chamber 21b or 21c in the muffler pipe 17 and near the rear surface of the front partition 20b or 20a of the expansion chamber. Since the short pipe 24 is connected and the drain discharge hose 25 is connected to the rear end of the short pipe 24, the drain generated in the expansion chamber is located in the lower surface where the expansion chamber is inclined upward (downward). The water flows along the short pipe 24 and is discharged to the outside via the drain discharge hose 25, and therefore, hardly accumulates in the expansion chamber.

Further, since the rear end opening 25a of the drain discharge hose 25 is located near the lower end of the license support portion 11b located at the rear end of the vehicle, the drain does not adhere to the rear arm or the like or the rear seat occupant.

Also, since the drain discharge hose 25 is inclined backward and upward to extend along the lower surface of the muffler pipe 17 and extended rearward, and furthermore, it is routed downward in the U-shape of the license support part,
The drain adhering to the wall of the expansion chamber partially collects on the inclined portion of the drain discharge hose 25 after the engine is stopped,
It is possible to prevent the drain from dropping to one place while the vehicle is stopped.

Furthermore, the drain discharge hose 25 is routed from the short pipe 24 connected to the lower surface of the expansion chamber of the silencer 17 to the vicinity of the lower end of the license support 11b. Since the license support portion 11b is arranged near the upper portion and has a short length up and down enough to mount the license plate 13, the drain discharge hose 25 can be shortened, and the drain is easily discharged. In addition, since it is not arranged near the center of the vehicle body where the other vehicle parts are assembled and assembled or near the swinging rear arm, the mounting operation is easy. The drain discharge hose 25 extends rearward along the lower surface of the muffler pipe 17 and from there a license support section.
Since it is routed downward in the U-shape of 11b, it is difficult to see from the outside, and it is possible to suppress the deterioration of the appearance due to the provision of the hose. Moreover, since the drain discharge hose 25 is routed rearward along the lower surface of the expansion chamber where the gas temperature inside is reduced, the durability is not impaired.

Also, mudguard 10, license bracket 11,
The taillight 12, the turn signal 26, and the drain discharge hose 25 are pre-assembled, so-called sub-assembly, and the drain discharge hose 25 can be connected to the short pipe 24 when attached to the vehicle body, so that the assemblability can be improved. .

〔Example〕

 Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

1 to 6 show an exhaust device according to an embodiment of the present invention.

In the figure, reference numeral 1 denotes a motorcycle provided with the exhaust system of the present embodiment, and a body frame 2 of the motorcycle is of a so-called double cradle type. A front fork 4 that rotatably supports the main pipe 2c is rotatably supported left and right, and a front end of a seat rail 2a disposed substantially horizontally is fixed to an upper portion of the main pipe 2c. Main pipe
A back stay 2b is arranged and fixed diagonally between the back stay 2b and the second stay 2b. A fuel tank 5 is provided near the connection of the seat rail 2a.
However, a two-seater seat 6 is mounted behind the seat, and a tail cowl 7 that covers the rear portion of the vehicle is disposed behind the seat 6. A rear arm 9 that pivotally supports the rear wheel 8 at the rear end is pivotally supported at the lower rear end of the main pipe 2c so as to be vertically swingable.

Above the rear wheel 8, a front mudguard 10 and a rear mudguard portion 11a, which is a front half of the license bracket 11, are disposed so as to cover the rear wheel 8, and the rear mudguard portion 11a is located in the tail cowl 7. doing. The license support portion 11b, which is the latter half of the license bracket 11, extends downward so as to be continuous with the tail cowl 7. The license support portion 11b has a substantially U-shaped cross section (see FIG. 4) and is located at the rear end of the vehicle.
13 are attached respectively.

A water-cooled two-cycle two-cylinder engine unit 14 is mounted substantially at the center of the body frame 2.
An exhaust pipe 15 for discharging exhaust gas to the rear of the vehicle is connected to an exhaust port of each cylinder 14a of the engine unit 14. Each of the exhaust pipes 15 includes an expansion pipe 16 connected to the exhaust port and a muffler pipe 17 connected to the expansion pipe 16. The expansion pipe 16 crosses a connection pipe part 16a connected to the exhaust port to the left and right, and a chamber part 16b
The first expansion chamber rises to near the lower edge of the fuel tank 5 and is bent substantially horizontally rearward. 16c is a protector for protecting the thigh of the driver M1.

The muffler pipe 17 is composed of a connecting pipe part 17a extending backward near the lower edge of the seat 6, a tapered pipe part 17b, and a straight pipe part 17c that is inclined slightly upward. It is covered with a side cover 18, and a protector 19 for improving the appearance is mounted on the outside of the straight pipe portion 17c to protect the vicinity of the thigh of the rear passenger M2. A substantially semicircular shielding plate 17d is welded and fixed to the inside of the rear end of the straight pipe portion 17c to prevent the periphery from being contaminated by exhaust gas.

The inside of the straight pipe portion 17c is partitioned by first and second partition walls 20a and 20b. The upstream side of the first partition wall 20a is in the second expansion chamber 21a, and the downstream side of the second partition wall 20b is in the third expansion chamber 21b. In addition, both partition walls 20a, 20b
The intervening portions serve as fourth expansion chambers 21c. The second expansion chamber 21a and the third expansion chamber 21b are connected to a first communication pipe.
22a, the third expansion chamber 21b and the fourth expansion chamber 21c are connected to the second communication pipe 2
2b, and the second partition 20b
The tail pipe 23 fixed to the outside projects from the rear end of the straight pipe part 17c outward. The tail end of the tail tube 23 is slightly bent and substantially horizontal, and the outer peripheral surface is covered with a sound absorbing material (glass wool) 23a.

Short pipes 24 are respectively connected to the left and right straight pipe sections 17c near the rear surface of the front partition wall 20a on the lower surface of the fourth expansion chamber 21c. Each short pipe 24 is the straight pipe part
A connecting portion 24a with 17c is formed in a funnel shape, is bent rearward of the vehicle, and a front end of a drain discharge hose 25 is connected to a rear end. The discharge hose 25 extends rearward along the lower surface of the straight pipe portion 17c, that is, above the rear wheel 8 so as to be inclined higher toward the rear and rearward.
The hose 25 is routed inside the U-shaped cross section of the license support 11b, and the rear end opening of the hose 25 is located at the lower end of the license support 11b. Reference numeral 25a denotes a throttle member for restricting exhaust gas from being discharged from the discharge hose 25. The rear end of the discharge hose 25 is a clamp member 27a fixed to the license support portion 11b, and the substantially central portion thereof is fixed by a clamp member 27b fixed to a support bracket 26a of the direction indicator 26. .

 Next, the operation and effect of this embodiment will be described.

The exhaust gas from the engine unit 14 expands in the chamber section 16b (first expansion chamber) of the expansion pipe 16 and contracts in the connection pipe section 17a of the muffler pipe 17, and then expands in the second to fourth expansion chambers 21a to 21c and The expansion and contraction are repeated in the first and second communication pipes 22a and 22b, and are discharged outward from the tail pipe 23.

In such exhaust gas discharge, the exhaust gas is silenced during the expansion and contraction processes and becomes low in temperature. However, the water vapor in the exhaust gas becomes
In particular, it is condensed and drained in the fourth expansion chamber 21c having a low temperature. Then, the drain is guided from the short pipe 24 through the discharge hose 25 to the lower end of the license support portion 1b of the license plate 11, and is discharged downward from the lower end.

As described above, in the present embodiment, since the discharge hose 25 is connected to the lower surface of the fourth expansion chamber 21c where the water vapor in the exhaust gas is easily condensed, most of the drain generated in the exhaust pipe 15 can be discharged to the outside. Thereby, it is possible to prevent the drain from accumulating in the inside and prevent the drain from being blown out at once, and as a result, it is possible to solve the problem of the contamination of the following vehicle and the like. In addition, since the drain generated inside is discharged downward from the lower end of the license plate 11 located at the rear end of the vehicle, the drain adheres to the rear arm 9 and the like and the rear passenger 2 of the motorcycle 1. Not even.

In addition, the discharge hose 25 of this embodiment is a
After the engine is stopped, since the area near the connection of the short pipe 24 is low.
The drain adhering to the wall of the expansion chamber is
Is collected temporarily at the front of the vehicle, and the drain can be prevented from dropping to one place while the vehicle is stopped.

Furthermore, in the present embodiment, the discharge hose 25 is routed between the rear end of the exhaust pipe 15 and the license plate 11 provided near the exhaust pipe 15, so that the discharge hose 25 is short. When viewed from the outside, the front part is located immediately below the straight pipe part 17c of the exhaust pipe 15, and the rear part is hidden inside the direction indicator 26 and the license bracket 11. For this reason, it is hard to be noticeable, and a decrease in appearance can be suppressed.

Further, in the present embodiment, since the throttle member 25a is attached to the rear end of the drain discharge hose 25, smoke exhausted from the hose 25 can be suppressed. In addition, even if such a throttle member is mounted, the drain is discharged without any trouble due to the internal pressure.

Furthermore, when attaching the drain discharge hose 25, the drain discharge hose 25 is attached to the license bracket 11 integrally formed with the mud guard 10 by the taillight 12 and the turn signal indicator 2.
The drain exhaust hose 25 may be connected to the short pipe 24 of the silencer 17 when the mud guard 10 is attached to the vehicle body frame in advance with the sub-assembly 6, thereby improving the assembling workability.

In the above embodiment, the discharge hose 25 is connected to the fourth expansion chamber 21.
Although connected to c, the discharge hose of the present invention may be connected to another position at the rear of the exhaust pipe, for example, to the third expansion chamber 21b. You may connect to both rooms. In this case, after the discharge hoses from both chambers are joined, they may be routed in the license plate. Also,
Although the above-described embodiment is a case of a two-cycle engine, the present invention can of course be applied to an exhaust system of a four-cycle engine.

〔The invention's effect〕

As described above, according to the exhaust system for a motorcycle according to the present invention, the muffler is arranged to be inclined slightly backward and upward, and the lower surface of the expansion chamber in the muffler and the front partition wall of the expansion chamber are formed. Since the short pipe bent backward was connected to the vicinity of the rear face, and the drain discharge hose was connected to the rear end of the short pipe, the drain generated in the expansion chamber flows into the short pipe along the inclined lower surface and the drain discharge hose is connected to the short pipe. Therefore, drainage is reliably prevented from accumulating in the expansion chamber.

Further, since the rear end opening of the drain discharge hose is located at the lower end of the license support portion located at the rear end of the vehicle, it is possible to prevent the drain from adhering to the rear arm or the like or the rear seat occupant.

In addition, the drain discharge hose was inclined upward and rearward along the lower surface of the muffler pipe, and extended rearward.From here, the cable was routed downward in the U-shape of the license support. The drain that has accumulated temporarily on the inclined portion of the discharge hose after the engine is stopped, and has the effect of preventing the drain from dropping to one place while the vehicle is stopped.

The drain discharge hose is routed from the short pipe connected to the lower surface of the expansion chamber of the silencer to the lower end of the license support, but the rear end of the silencer is located near the upper part of the license support and Since the portion has a short vertical length enough to mount the license plate, the hose can be shortened, and the drain is easily discharged. In addition, since the cable is not routed near the center of the vehicle body where the other vehicle parts are assembled and assembled or near the swinging rear arm, the mounting operation is easy. In addition, the drain discharge hose extends rearward along the lower surface of the muffler tube, and is routed downward in the U-shape of the license support from here, so it is difficult to see from the outside,
There is an effect that the deterioration of the appearance due to the provision of the hose can be suppressed. Moreover, the drain discharge hose extends rearward along the lower surface of the expansion chamber where the gas temperature inside is reduced, so that the durability is not impaired.

Also, in assembling, the taillight, turn signal, and drain discharge hose are pre-assembled on the license bracket integrated with the mudguard, and after attaching the mudguard to the body frame, the drain discharge hose is connected to the short pipe of the silencer. The connection can be performed, and there is an effect that the assembly workability can be improved.

[Brief description of the drawings]

1 to 6 are views for explaining an exhaust system according to an embodiment of the present invention. FIG. 1 is a side view of a rear part of an exhaust pipe, FIG. 2 is a sectional side view of the rear part, 3 and 4 are sectional views taken along the line III-III and IV-IV of FIG. 1, respectively.
FIG. 5 is a front view of the exhaust system of the embodiment, and FIG. 6 is a side view of a motorcycle to which the embodiment is applied. In the figure, 14 is an engine, 15 is an exhaust pipe, 17 is a silence pipe,
8 is a rear wheel, 11 is a license bracket, 11b is a license support, 13 is a license plate, 20a and 20b are bulkheads, 2
1b to 21c are expansion chambers, 24 is a short pipe, 25 is a drain discharge hose, 2
5a is a rear end opening (aperture member).

Claims (1)

(57) [Claims] 1. An automatic exhaust system, comprising: an exhaust pipe connected to an engine extending to a rear portion of a vehicle through an upper portion on a side of a vehicle, and a silence pipe at a rear end of the exhaust pipe for silencing exhaust gas and discharging the exhaust gas to the rear of the vehicle. In a motorcycle exhaust device, a license bracket is integrally formed on a mudguard that covers the upper part of a rear wheel, and a license support portion of the license bracket is extended downward to be positioned at the rear end of the vehicle and formed into a substantially U-shaped cross section. A tail light and a direction indicator are attached to the license bracket, and a license plate is attached to a central portion of a rear surface of the license support portion, and the muffler is disposed to be inclined slightly upward and a rear end of the muffler is attached. A plurality of expansion chambers are provided in the vicinity of the upper portion of the license support portion and partitioned by a partition in the muffler pipe, and a lower surface of the expansion chamber and a front side of the expansion chamber. A short tube bent backward is connected to the vicinity of the rear surface of the wall, a drain discharge hose is connected to the rear end of the short tube, and the drain discharge hose is inclined upward and rearward along the lower surface of the sound deadening tube. It extends rearward, is routed downward in the U-shape of the license support portion following the extension end, and positions the rear end opening of the drain discharge hose at the lower end portion of the license support portion, and An exhaust device for a motorcycle, wherein a discharge hose is fixed to a license bracket.