JPS6260914A - Exhaust device for motorbicycle - Google Patents

Abstract

PURPOSE:To improve the balance of exhaust and to facilitate assembling work by connecting the exhaust pipe for the righthand cylinder of the rear cylinder block to the exhaust pipe for the left-hand cylinder of the front cylinder block in a side-view V-type four cylinder engine. CONSTITUTION:The exhaust pipe 21 from the righthand cylinder V3 of a rear cylinder block 6b is connected to the exhaust pipe 20 from the lefthand cylinder V2 of a front cylinder block 6a, and further the exhaust pipe 23 from the lefthand cylinder V4 of the rear cylinder block 6b is connected to the exhaust pipe 19 from the righthand cylinder V1 of the front cylinder block 6a. Thus, the length of each of the exhaust pipes from the rear cylinder block 6b can be made sufficiently long, enabling exhaust to maintain a good balance. Further, by making the connecting directions of exhaust pipes from the rear cylinder block to be nearly at right angles to the axis of the vehicle, assembling workability can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to an exhaust system having features in the arrangement and connection of exhaust pipes from a type II engine.

(Prior Art) As an engine mounted on a motorcycle, a four-cylinder engine is known, which has a V-shaped side surface formed by a cylinder block at the front and a cylinder block at the rear.

Exhaust systems applied to such four-cylinder engines generally connect the exhaust pipes from the right cylinders of the front and rear cylinder blocks to the right side muffler, and then connect the exhaust pipes from the left cylinders of the front and rear cylinder blocks to the right side muffler. The two merge in the middle and connect this to the left muffler.

(Problems to be Solved by the Invention) With the exhaust pipe structure as described above, it is not possible to make the length of the exhaust pipe extending from the cylinder of the rear cylinder block sufficiently long. If an attempt is made to lengthen the exhaust pipe that tends to cause imbalance, and extends from the cylinder of the rear cylinder block, the exhaust pipe must be curved in a complicated manner, which causes problems in terms of exhaust resistance and space.

(Means for Solving the Problems) In order to solve the above problems, the present invention provides a four-cylinder engine with a V-shaped side surface, in which the exhaust pipes from the left and right cylinders of the front cylinder block are directed rearward along the engine. The exhaust pipe from the right cylinder of the rear cylinder block is connected to the exhaust pipe from the left cylinder of the front cylinder block.
By connecting the exhaust pipes from the left cylinder of the rear cylinder block to the exhaust pipes from the right cylinder of the front cylinder block, the length of the exhaust pipes from the rear cylinders is lengthened.
Furthermore, the direction in which the exhaust pipe from the rear cylinder is connected is approximately perpendicular to the vehicle axis, making assembly easier.

(Example) Embodiments of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 is an overall side view of a motorcycle to which an exhaust system according to the present invention is applied, FIG. 2 is a side view of the exhaust system, and FIG. 3 is a plan view of the exhaust system.

First, to explain the outline of a motorcycle, the frame of a motorcycle is a front frame (1), a catcher frame (2), and a rear frame (2).
The front frame (1) is made of Herad tube (
3), a pair of left and right main frames (4) whose front ends are fixed to the head tube (2) and extend rearward and downward; and whose upper ends are fixed to the head tube (3) and which extend rearward and downward. It consists of a pair of left and right town frames (5) and an engine (6) installed between the main frame (4) and down frame (5).

The fixation of the front end of the main frame (4) and the front end of the down frame (5) to the Herad tube (3) is reinforced by the gusset plate (7), and
The steering shaft inserted into the head tube (3) has an upper bridge (8) and a lower bridge (9).
Attach the handle (10) to the upper bridge (8).
Install the upper bridge (8) and lower bridge (
9) supports the upper part of the front fork (11), and the lower end of this front fork (11) supports the front wheel (12).
) is rotatably supported.

A fuel tank (13) is located above the front of the main frame (4).
), the bottom surface of this fuel tank (13) is made into four parts upward, and an air cleaner (14) is arranged in this recess,
A carburetor (15), (
15) are placed. In addition, a radiator (18) is attached to the top of the down frame (5), and a footstep mounting bracket (17) is attached to the bottom end of the engine (6).
It is stuck between.

Here, the engine (8) is connected to the front cylinder block (8).
a) is tilted forward, and the rear cylinder block (8b) is tilted backward to form a V-shaped side surface, and each cylinder block (Eta
), (8b) Pair of left and right cylinders (V+), (V2
).

(V3) and (V4) (see Figure 3), and the engine (8) is mounted on the main frame (4) and down frame (5).
8), and in the installed state, the upper part of the rear cylinder block (sb) protrudes beyond the main frame (4) in three directions.

As shown in FIG. 3, the exhaust pipe (19) is connected to the right cylinder (Vl) of the front cylinder block (6a).
) and the left cylinder (v2) are respectively extended rearward along the engine (6), and are connected to the right cylinder (v2) of the rear cylinder block (6b).
3) The exhaust pipe (21) from F
It is connected to the exhaust pipe (20) from the left cylinder (v2) at the front through the pipe (22), which curves further to the left, and joins the exhaust pipe (20) from the left cylinder (v2) at the front. Exhaust pipe (23) from the left cylinder (v4)
) once extends to the right rear, then curves to the left, then curves further to the right, and connects and merges from the front right cylinder (vl) to the exhaust pipe (18) via a joint (24) in the center of the vehicle body. Here is the exhaust pipe (21).

The direction of the facing material for the joints (22) and (24) of (23) is approximately perpendicular to the vehicle body axis (N) to improve ease of assembly.

The exhaust pipe (25) on the downstream side of the confluence of the exhaust pipes (19) and (23) extends rearward along the right side of the vehicle body, and the rear end of this exhaust pipe (25) has a muffler (2B). ) are tied together, and the exhaust pipe (27) on the downstream side of the confluence of the exhaust pipes (20) and (21) extends rearward along the left side of the vehicle body, and the rear end of this exhaust pipe (27) There is a muffler (2
8) is bound.

By the way, the front half of the rear frame (2) consists of an underframe (23) that rises diagonally rearward and upward, and a seat rail (30) that extends horizontally in the V direction, and the front end of the underframe (29) is connected with bolts. holder (31
) from the inside, and the front end of the seat rail (30) is fixed to the main frame (4).

Further, a seat (32) is supported on the seat rail (30), and the seat rail (30) and the under frame (
29) is covered with a cover (33). Furthermore,
Mission case (34) forming the rear part of the engine (6)
The swing arm (35
The front end of the swing arm (
3B) is rotatably supported. A rear wheel shock absorbing mechanism that exhibits progressive characteristics, including a horizontal damper (37), is arranged between the middle part of the swing arm (35) and the transmission case (34).

(Effects of the Invention) As explained above, according to the present invention, in a lateral V-type four-cylinder engine having front and rear cylinder blocks, the exhaust pipe led out from the right cylinder of the rear cylinder block is connected to the front cylinder block. The exhaust pipe leading from the left cylinder of the rear cylinder block is connected to the exhaust pipe leading from the right cylinder of the front cylinder block, so that the exhaust pipe leading from the left cylinder of the rear cylinder block is connected to the exhaust pipe leading from the left cylinder of the rear cylinder block. The length of the exhaust pipe from the cylinder can be made sufficiently long, and the exhaust balance can be made good.

Furthermore, since the direction in which the exhaust pipes from the cylinders of the rear cylinder block are connected is approximately perpendicular to the vehicle body axis, many advantages are achieved, including excellent assembly and maintainability.

[Brief explanation of the drawing]

FIG. 1 is an overall side view of a motorcycle to which an exhaust system according to the present invention is applied, FIG. 2 is a side view of the exhaust system, and FIG. 3 is a plan view of the exhaust system. In the drawings, (6) is the engine, (6a) is the front cylinder block, and (8b) is the rear cylinder block. (19), (20), (21), (23), (25),
(27) is the exhaust pipe, (22), (24) are the joints, (2B), (28) are the mufflers, (N) is the vehicle axis, (V+), (V2), (V3), (V4
) is a cylinder.

Claims (1)

[Claims] In a motorcycle equipped with a four-cylinder engine having a side V-shape formed by a front cylinder block and a rear cylinder block, exhaust pipes extend rearward from the left and right cylinders of the front cylinder block, respectively, along the engine; The exhaust pipe from the right cylinder of the rear cylinder block is connected to the exhaust pipe extending from the left cylinder of the front cylinder block, and the exhaust pipe from the left cylinder of the rear cylinder block is connected to the right cylinder of the front cylinder block. The exhaust pipe is connected to the exhaust pipe extending from the rear cylinder block, and the connection direction of the exhaust pipe from the cylinder of the rear cylinder block to the exhaust pipe from the cylinder of the front cylinder block is approximately perpendicular to the vehicle axis. exhaust system for motorcycles.