JPS6036710A - Exhaust apparatus for motor cycle - Google Patents

Abstract

PURPOSE:To enable to arrange accessory parts of an engine around the engine body compactly, by disposing exhaust pipes connected to respective cylinders and a member for pivotal support of a swing arm for supporting a rear wheel in a space defined by an oil pan and a cylinder of a horizontally opposed engine. CONSTITUTION:Intake ports 23 of a horizontally opposed type water-cooled 4-cylinder engine 8 are formed in the upper surface of the engine 8 while exhaust ports 24 are formed in the lower surface of the engine 8. The exhaust ports 24 are connected to a silencer via exhaust pipes 28a-28h. Here, exhaust pipes 28s-28h connected to respective cylinders are concentrated by concentrated pipes 28a, 28b which are disposed in a space S defined substantially between the rear surface of an oil pan 20a and a virtual horizontal plane V passing the rear surface of rear cylinders 22 and between the lower surface of the rear cylinders 22 and a virtual horizontal plane H passing the lower surface of the oil pan 20a. Further, a member 15 for pivotally supporting a swing arm 14 on the vehicle frame is disposed also in the above mentioned space S being located near the lower surface of the rear cylinders 22 and in a gap 29 between an exhaust pipe 28d and a crankcase 20.

Description

[Detailed description of the invention] The present invention relates to an exhaust system for a motorcycle.

2. Description of the Related Art Recently, motorcycles have been considered to be equipped with horizontally opposed engines having cylinders projecting from the crankcase in the front and rear horizontal directions of the vehicle body. In this case, it is conceivable that the configuration related to the cylinders is as follows. That is, an exhaust pipe is extended from the exhaust port of each cylinder, each extending end of this exhaust pipe is connected at a collecting part, and this collecting part and a muffler at the rear of the engine are connected by another exhaust pipe. On the other hand, the front end pivot portion of the swing arm that supports the rear wheel is located behind the engine.

By the way, in the above configuration, since each cylinder protrudes from the crankcase in the longitudinal horizontal direction, the space formed below the engine can be utilized for arranging each device. However, on the other hand, within the limited overall length of the vehicle, the front and rear dimensions of the engine become longer, increasing restrictions in this front and rear direction.

In addition, the exhaust pipe in the above configuration is not suitable for engine performance.
It is required to make the dimensions from the front and rear cylinders to the gathering part as equal as possible, and it is also necessary to avoid heating the engine due to the exhaust pipe. Furthermore, the swinging arm is
It is desirable to make the length as long as possible while avoiding interference with the vehicle running performance 1-1 cylinder.

Therefore, it is necessary to provide the exhaust pipe, the gathering part, the swing arm, etc. so that they can individually perform their functions in a limited space as shown in (-). Moreover, in addition to these points, in order to facilitate assembly, it is also required to connect these engine-related devices with other devices in a simple manner.

However, it is not easy to construct a device that satisfies many of these conditions within a limited space.

This invention was made in view of the above-mentioned circumstances, and consists of arranging the devices around the engine body so that each device can perform a sufficient function, and using these devices as one block to connect the devices around the engine body. The purpose is to simplify the related configuration of equipment and other equipment, to facilitate the assembly of each equipment, and to maintain the length of the swinging arm at a specified length.
The purpose is to make effective use of space between rooms.

” - A feature of this invention to achieve the above object is that the exhaust pipe, etc. of the part connected to the cylinder is arranged in a space partitioned between the oil pan and the cylinder at the bottom of the crankcase. In addition, the pivot portions of the swinging arms supporting the rear wheels are arranged in the same space.

Embodiments of the present invention will be described below with reference to the drawings.

1 to 6, the body frame 2 of the motorcycle 1 is a diamond-shaped frame, which includes a -1-1 lower frame 4°6 extending from the steering shaft tube 3, and a -1 partial frame 4°6.
-1
-5 An engine 8 is installed at the rear end of the lower frames 4 and 6. A front fork 12 having a handle 9 and a front wheel 11 is supported on the steering shaft tube 3 . A swinging arm 14 for supporting a rear wheel 13 is movably supported on a bracket 4a at the rear end of the upper frame 4 behind the engine 8 via a pivot 15, and the engine 8 and the rear wheel 13 are connected by a chain transmission. They are interlocked in the device IO. Further, a shock absorber 16 is installed between the swing arm 14 and the rear frame 7. 1
7 is a fuel tank, 18 is a seat, 19R is a right silencer placed on the right side of the rear wheel 13, and 19L is a left side silencer placed on the left side of the rear wheel 13.

-1- The engine 8 is a four-cylinder horizontally opposed water-cooled engine, and includes a right front cylinder 21R and a left front cylinder 21L that protrude forward from the crankcase 20, and a right rear cylinder 22R and a left rear cylinder that protrude rearward. It has 22L cylinders, and the front and rear cylinders are configured to operate with a phase of 360°C. Each of these cylinders has an intake port 23 on its top surface.
However, an exhaust port 24 is formed on the bottom surface, and each intake port 2
3 is communicated with the carburetor 27 via the intake pipe 26, and
Each exhaust port 24 and each of the mufflers 19R, 19L are communicated through an exhaust pipe 28.

The exhaust pipe 28 will be explained. A front collecting pipe 28a and a rear collecting pipe 28b, which are collecting parts, are provided at the rear of the oil pan 20a projecting from the lower part of the crankcase 20. The first exhaust pipe 28c is the right front cylinder 21R.
After once extending downward, it is sequentially bent outward, backward, and inward of the vehicle body, and connected to the right end of the front collecting pipe 28a. In addition, the second exhaust pipe 28d extends from the right rear cylinder 22R to the rear of the cylinder 22R and downward to the inside of the vehicle body so as to have a gap 29 between it and the crankcase 20, and then sequentially extends outward, forward, and inward from the vehicle surface. The front collecting pipe 28a is bent and connected to the right end of the front collecting pipe 28a to join the first exhaust pipe 28c. And the front collecting pipe 28a
The left end of the left muffler 19L is connected to the third exhaust pipe 28e. On the other hand, a fourth exhaust pipe 28f that connects the left front cylinder 21L and the rear collecting pipe 28b, a fifth exhaust pipe 28g that connects the left rear cylinder 22L and the rear collecting pipe 28b, and a right silencer 19R of the rear collecting pipe 28b. The sixth exhaust pipe 28 connects the
h are provided, and these fourth to sixth exhaust pipes 28f to 28h are provided.
are formed almost symmetrically with the first to third exhaust pipes 28c to 28e with respect to the center of the vehicle body. Further, a seventh exhaust pipe 28 is connected to the third exhaust pipe 28e and the sixth exhaust pipe 28h in order to communicate these two.
i is constructed.

In the above case, each of the collecting pipes 28a, 28b and the second and fifth exhaust pipes 28d, 28g are located between the rear surface of the oil pan 20a and the virtual vertical plane V passing through the rear surface of the rear cylinders 22R, 22L, and the lower surface of the oil pan 20a. The rear cylinders 22R and 22L are disposed in a space S substantially surrounded by a virtual horizontal plane H passing through the rear cylinders 22R and 22L.

Then, in order to extend the swinging arm 14 forward, a pivot portion 15 of the swinging arm 14 relative to the vehicle body frame 2 is installed near the lower surfaces of the left and right rear cylinders 22L and 22R and in the gap 29. Placed. Also, rear frame 7
A footless 31 is fixed to the hood 31 via a bracket 7a, and by bending the second and fifth exhaust pipes 28d and 28g inward to the vehicle body, the hoodless 31 is fixed at a predetermined position and these second and fifth exhaust pipes are bent. Interference with 28d and 28g is avoided.

In addition, in the case of "-", the seventh exhaust pipe 28i may not be provided.

According to the configuration of the above embodiment, since the exhaust pipe of the cylinder on the negative side is connected to the muffler on the other side across the vehicle body, the exhaust pipe can be made sufficiently long, which is beneficial for cooling the exhaust gas.

Figures 7 and 8 show other embodiments, in which the Oil Nokun 20
A box-shaped collection box 28j, which is a collection part, is arranged behind a, and the right,
No. 1.4 exhaust pipe 28c from left front cylinders 21R and 21L
, 28f are connected to the collecting box 28j. In addition, the 2.5 exhaust pipes 28d and 28g are arranged between the right and left rear cylinders so that there is a gap 29 between them and the crankcase 20.
After extending downward from 2R and 22L and into the vehicle body,
It is folded back forward and its end is connected to the collecting box 28j. Then, the both sides of the collection box 28j and the right and left silencers 19
R and 19L are connected by 3.6th exhaust pipes 28e and 28h.

The other configurations are the same as those in the previous embodiment.

The effects of this invention are as follows. In other words, in the case of a horizontally opposed engine, the engine body consisting of the crankcase and cylinders is flat as a whole, and a space is formed below the engine body, but this is because the oil pan is formed under the crankcase. Space is used effectively. Moreover,
In the space formed by this oil pan and cylinder,
Because the exhaust pipes connected to the cylinders have been arranged, the engine body has a compact structure with a single unit, and this makes it possible to relate these to other machines with a simple configuration, making assembly easier. Facilitation is achieved.

Also, each rear cylinder is located closer to the collecting box than each front cylinder, but the exhaust pipes extending from each rear cylinder are
Since the exhaust pipe once extends rearward and downward and then is connected to the collecting part, it is easy to make the length of this exhaust pipe equal to the length of the exhaust pipe extending from each front cylinder to the collecting part. If the exhaust pipes are of equal length in this way, the characteristics of the exhaust pipes for the front and rear cylinders will be equalized, which is beneficial in terms of engine performance. Moreover,
The exhaust pipe connected to the rear cylinder was extended rearward and downward from the exhaust port with a gap between it and the crankcase, which prevented the engine from heating up unnecessarily due to exhaust pipe heating. Ru.

In addition, because the pivot of the swinging arm is located near the bottom surface of the rear cylinder and in the gap between the crankcase and the exhaust pipe connected to the rear cylinder, the pivot can be maintained at a predetermined height. By arranging the swing arm as far forward as possible, the swing arm can be made longer, and the space can be utilized more effectively.

[Brief explanation of drawings]

The figures show an embodiment of the invention, in which Fig. 1 is an overall side view of a motorcycle, Fig. 2 is a partially enlarged view of Fig. 1, and Fig. 3 is a partial enlarged view of a motorcycle.
Fig. 4 is a view taken along the line ■-IV of Fig. 2, Fig. 5 is a view taken along the V-V line of Fig. 1, and Fig. 6 is a perspective view of the exhaust pipe. 7 and 8 show other embodiments, FIG. 7 is a partial sectional view corresponding to FIG. 2, and FIG. 8 is a perspective view of the exhaust pipe. l...Motorcycle, 2...Body frame, 8. Engine, 13..Rear wheel, 14. Fist/swing arm, I5. Pivot arm, 1-9R..Right silencer, 19L..Left. silencer,
20th Race/Crankcase, 21R--Right front cylinder, 21
L-Φ Left front cylinder, 22R...Right rear cylinder, 22L-...
Left rear cylinder, 24-・Exhaust [-1, 28・-Exhaust pipe, 2
9.Gap, ■.Virtual vertical plane, H-.Virtual horizontal plane, S
◆・Space. Patent applicant Yamaha Motor Co., Ltd.

Claims (1)

[Claims] 1. A horizontally opposed engine is provided with cylinders protruding from the crankcase in the front and rear horizontal directions of the vehicle body, and an exhaust pipe extends from the exhaust port on the bottom of each cylinder. They are connected at a gathering part, and this gathering part and a silencer at the rear of the engine are connected by another exhaust pipe, while the front end pivot of the swinging arm that supports the rear wheel is located at the rear of the engine. In a motorcycle, an oil pan is provided protruding from the lower part of the crankcase, and there is a gap between the rear surface of the oil pan and an imaginary vertical plane passing through the rear rear surface of the cylinder, and between an imaginary horizontal plane passing through the bottom surface of the oil pan and the bottom surface of the rear cylinder. The gathering part is arranged in a space that is almost surrounded by the pivot arm of the swing arm is connected to the gathering part after being extended to the rear cylinder, and
An exhaust system for a motorcycle, characterized in that it is disposed in a gap between the crankcase and the exhaust pipe.