JPH0776527B2 - Motorcycle exhaust system - Google Patents

Description

The present invention relates to an exhaust system for a motorcycle equipped with a 4-cycle engine.

[Conventional technology]

For example, in a motorcycle equipped with a V-type 4-cycle engine, in order to enhance engine output and noise reduction effect, exhaust pipes led out from the front and rear cylinders are connected to a common exhaust chamber, and the exhaust chamber has a cylindrical shape. The two silencers are connected to each other, the exhaust gas from each cylinder is once guided to the exhaust chamber, and then distributed to both silencers.

By the way, recently, due to the external design requirements, two silencers are vertically arranged on one side of the vehicle body, and the exhaust pipe of the rear cylinder is guided to the side of the engine. There is a demand to emphasize the line leading from the exhaust pipe to the rear and flowing from the exhaust pipe to the silencer as one of the appearance elements.

[Problems to be solved by the invention]

However, in the exhaust device including the exhaust chamber,
Since the exhaust chamber is installed at a deep position in the vehicle body, the rear end of the exhaust pipe connected to the exhaust chamber has to be bent toward the inside of the vehicle body in front of the silencer.

Therefore, the handling of the exhaust pipe becomes complicated, and it is extremely difficult to design the exhaust pipe and the silencer in a continuous manner.

[Means for solving problems]

Therefore, in the present invention, a plurality of exhaust pipes derived from the engine are guided to one side of the vehicle body and arranged vertically, and the rear ends of these exhaust pipes are bent toward the inside of the vehicle body to form a common exhaust gas. When connecting a plurality of cylindrical silencers that are vertically stacked behind the exhaust pipe to the exhaust outlet of the exhaust chamber while connecting to the chamber, exhaust the exhaust gas to the outer circumference of each exhaust pipe. At least the rear end of the pipe is covered from the side, and an exhaust cover shaped like an exhaust pipe that passes through the side of the connection between the exhaust pipe and the exhaust chamber and is continuous to the front end of the silencer is provided. It is characterized by that.

[Action]

According to this structure, the exhaust cover that covers the rear end of the exhaust pipe extends toward the rear silencer side regardless of the bending direction of the rear end of the exhaust pipe. It is possible to obtain the appearance as if it is directly connected to the exhaust pipe, and the lines from the exhaust pipe to the silencer can be incorporated as one of the appearance elements.

Further, since the connecting portion between the exhaust pipe and the exhaust chamber is also covered with the exhaust cover, a plurality of exhaust systems are neatly packed and the appearance is improved.

Example of Invention

The present invention will be described below based on an embodiment shown in the drawings.

In FIG. 8, reference numeral 1 is a frame constituting a vehicle body, and a steering head pipe 2 at its front end is connected to a main member 3 having a box-shaped cross section. A four-cycle V-type two-cylinder engine 4 is suspended below the main member 3. In this engine 4, a front cylinder 6 and a rear cylinder 7 are arranged on a crankcase 5 in a substantially V shape in a side view, and a carburetor 8 is arranged between these cylinders 6, 7.

In FIG. 8, reference numeral 9 is a front fork, 10 is a frame cover in the shape of a fuel tank, and 11 is a seat.

By the way, in the engine 4, the front cylinder 6 has front exhaust and the rear cylinder 7 has rear exhaust, and exhaust pipes 13 and 14 are led out from exhaust ports 12 of these cylinders 6 and 7, respectively. The exhaust pipe 13 of the front cylinder 6 is led out downward through the front of the crankcase 5, and the lower end thereof is led substantially rearward through the lower right side of the crankcase 5. Further, the exhaust pipe 14 of the rear cylinder 7 is led to the right side immediately after the exhaust port 12, and then is guided obliquely downward and forward substantially parallel to the axis of the rear cylinder 7, and is led to the right end of the rear end of the crankcase 5. ing. And this exhaust pipe
The reference numeral 14 is bent to the rear on the right side of the crankcase 5 in a substantially U-shape, and is then guided rearward over the exhaust pipe 13 from the front cylinder 6 as shown in FIGS. And the rear ends of these exhaust pipes 13 and 14 are crankcase 5
Is bent toward the left side of the vehicle body.

A large-capacity exhaust chamber 16 in the shape of a flat tank is arranged in a portion where the rear ends of the exhaust pipes 13 and 14 are exposed, that is, in the space between the crankcase 5 and the rear wheel 15. Exhaust gas inlet 17 provided on the upper surface of this exhaust chamber 16
The rear ends of the exhaust pipes 13 and 14 are welded to each other.

Further, behind the exhaust pipes 13 and 14, a pair of cylindrical silencers 1
8,19 are arranged. These mufflers 18 and 19 extend parallel to each other in the front-rear direction and are arranged one above the other, and their front ends are closed by a front plate 20. The front ends of the mufflers 18 and 19 are located on the right side of the exhaust chamber 16, and exhaust inlets 21 and 21 are formed on the inner surface of the front ends. The exhaust inlets 21 and 21 are connected to the exhaust outlet 22 provided on the upper surface of the exhaust chamber 16 via a communication pipe 23. Therefore, the exhaust from the cylinders 6 and 7 is exhausted from the exhaust pipe 13. After being once introduced into the exhaust chamber 16 via 14 and 14, it is distributed to both silencers 18 and 19 from here.

The silencers 18, 19 are formed to have an outer diameter larger than that of the exhaust pipes 13, 14.

By the way, exhaust covers 24 and 25 made of sheet metal are attached to the outer peripheries of the exhaust pipes 13 and 14 led out from the cylinders 6 and 7, respectively. As shown in FIGS. 4 and 6, the exhaust cover 24 of the front exhaust pipe 13 is formed in a substantially semicircular cross section so as to cover the rear end portion of the exhaust pipe 13 from the outside by about a half circumference. After passing through the side of the exhaust chamber 16 from the rear end portion of the exhaust pipe 13, it is extended in a smooth curve toward the front end portion of the lower muffler 18. Moreover, the curvature R of the exhaust cover 24 is gradually widened to the same as the outer diameter of the front end portion of the exhaust cover 24 as it goes to the rear silencer 13 side. Therefore, the exhaust cover 24 is viewed from the side. It is shaped like an exhaust pipe.

Such an exhaust cover 24, by press-fitting the exhaust pipe 13 into the ring 26 welded to the inner periphery of the front end thereof, by butt welding the end member 27 welded to the inner periphery of the rear end to the front plate 20, It is integrated with the exhaust pipe 13 and the silencer 18, and covers the space between the exhaust pipe 13 and the silencer 18 from the side.

On the other hand, the exhaust cover 25 of the rear exhaust pipe 14 is provided over the entire length of the exhaust pipe 14, and has a substantially semicircular cross section that laterally covers the portion of the exhaust pipe 14 that extends to the right side of the vehicle body. Is formed in. The rear end portion of the exhaust cover 25 is extended above the exhaust cover 24 toward the front end portion of the upper muffler 19 in a smooth curve, and the curvature R of the rear end portion is one of the upper side. Rear silencer as well as the exhaust cover 24
It gradually widens as it progresses to side 19. Then, the exhaust cover 25 is inserted through the exhaust pipe 14 into the retaining rings 29, 30 welded to the inner periphery of the front end portion and the inner periphery of the intermediate portion, and while welding the intermediate retaining ring 30 and the exhaust pipe 14, The end member 31 welded to the inner circumference of the rear end of the exhaust cover 25 is butt-welded to the front plate 20 of the silencer 19 to be integrated with the exhaust pipe 14 and the silencer 19, and the exhaust pipe 14 and the silencer are integrated. It covers the space between it and the container 19 from the side.

According to such a configuration, the exhaust covers 24, 25 attached to the outer peripheries of the exhaust pipes 13, 14 are directly attached to the rear silencers 18, 19 regardless of the bending direction of the rear ends of the exhaust pipes 13, 14. Since it extends in a smooth curved line toward, the two exhaust pipes 13 and 14 are disposed even though the exhaust chamber 16 is located between the exhaust pipes 13 and 14 and the silencers 18 and 19. The appearance is obtained as if it were directly connected to the silencers 18 and 19. Therefore,
The line from the exhaust pipes 13 and 14 to the silencers 18 and 19 can be emphasized as one of the appearance elements, which is convenient in design.

Further, due to the existence of the exhaust covers 24, 25, the exhaust pipes 13, 14
Since the connection part between the exhaust chamber 16 and the exhaust chamber 16 is also covered,
It also has the advantage that the complicated exhaust system can be neatly filtered and the appearance and product value can be improved.

The engine according to the present invention is not limited to the V-type two-cylinder engine, but may be, for example, a parallel two-cylinder engine, a four-cylinder engine, or a four-cylinder engine.
A single cylinder engine may be used as long as two exhaust pipes are derived from one cylinder like a valve engine.

〔The invention's effect〕

According to the present invention described in detail above, it is possible to obtain an appearance as if the exhaust pipe is directly connected to the muffler, and the line from the exhaust pipe to the muffler is emphasized and incorporated as one of the appearance elements. be able to. In addition, it has the advantage that the complicated exhaust system can be neatly filtered and the appearance and product value can be improved.

[Brief description of drawings]

The drawings show one embodiment of the present invention. FIG. 1 is a side view of the entire exhaust system, FIG. 2 is a plan view of the same, and FIG. 3 is a side view showing the positional relationship between the exhaust pipe, the exhaust cover, and the silencer. 4 and 5 are plan views of the exhaust cover, and FIG. 5 is V in FIG.
Fig. 6 is a sectional view taken along line VI-VI in Fig. 4, Fig. 7 is a sectional view taken along line VII-VII in Fig. 2, and Fig. 8 is a side surface of the motorcycle. It is a figure. 1 …… Body (frame), 4 …… Engine, 13,14 ……
Exhaust pipe, 16 ... Exhaust chamber, 18, 19 ... Silencer, 24,
25 ... Exhaust cover.

Claims (1)

[Claims] 1. A plurality of exhaust pipes derived from an engine are guided to one side of a vehicle body and arranged in parallel vertically, and the rear ends of these exhaust pipes are bent toward the inside of the vehicle body to form a common exhaust chamber. While connecting, to the exhaust outlet of this exhaust chamber,
An exhaust device in which a plurality of cylindrical silencers arranged vertically above the exhaust pipe are connected, wherein at least the rear end of the exhaust pipe is laterally covered on the outer circumference of each of the exhaust pipes. At the same time, an exhaust device having a shape of an exhaust pipe passing through the side of the connecting portion between the exhaust pipe and the exhaust chamber and continuing to the front end of the silencer is provided. .