JPS58119914A - Exhaust of v-type engine for autobicycle - Google Patents

Abstract

PURPOSE:To prevent the drop of output from an engine while to facilitate the assembling, by bending an exhaust tube at the rear cylinder side of a V-type engine at the outside of a collecting chamber and connecting to the collecting chamber. CONSTITUTION:A rear exhaust tube 20 is dropped linearly while slightly holding the upper section toward the rear of a cylinder head cover 17a of a rear section cylinder unit 17 while at the midway it is bent forward from the lower section of a collecting chamber 19 through a joint 21 and further bent in semi-circle at the front of the chamber 19 then finally connected to the right side front section of the chamber 19. The exhaust gas produced from an engine 14 will pass through front and rear exhaust tubes 18, 20 then combined in said chamber 19 where it is branched by left and right mufflers 22, 22.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improvement in an exhaust system for a motorcycle equipped with a V-type engine.

When a motorcycle is equipped with a V-type engine in which the crankshaft is placed horizontally, that is, in the width direction of the vehicle, and the cylinders are V-shaped on the sides, each exhaust pipe of the engine runs from the front downward and to the rear of the front cylinder. It extends and is connected to the collecting chamber, and in the rear cylinder, it hangs downwardly and is connected to the collecting chamber.

In such an exhaust pipe, the length of the exhaust pipe extending from the rear cylinder is necessarily shorter than that of the exhaust pipe extending from the front cylinder due to space considerations. Unfavorable for utilizing pulsation effect.

Therefore, in order to equalize the length of the exhaust pipes of both cylinders, the exhaust pipe on the rear cylinder side was bent to match the required length of the exhaust pipe in the collecting chamber, but due to the space in the chamber, the exhaust pipe was bent. The number of bends increases, the radius of curvature of the bends decreases, the bending loss of the exhaust pipe increases, and as a result, the exhaust resistance increases, leading to a reduction in the output of the rear engine.

Furthermore, it is troublesome to assemble an exhaust pipe that includes many bends, and this reduces assembly work efficiency.

In view of the above-mentioned problem in the exhaust system of a V-type engine, the present inventor has devised the present invention to effectively solve the problem. By bending the exhaust pipe outside the collecting chamber and connecting it to the collecting chamber, the number of bent parts of the exhaust pipe can be reduced, and at the same time, the radius of curvature of the bent parts can be kept large, reducing bending loss of exhaust gas and reducing exhaust resistance. An object of the present invention is to provide an exhaust system for a V-type engine for a motorcycle, which can prevent a decrease in engine output, and can simplify assembly and improve assembly workability.

A preferred embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 is an overall side view of a motorcycle equipped with an exhaust system according to the present invention, and FIG. 2 is a plan view of a collecting chamber portion of the exhaust system.

In the motorcycle 1 shown in FIG. 1, a front fork 5 that supports a front wheel 4 via a head tube 3 at the front of a body frame 2 is pivotably supported by upper and lower bridges 6.7, and an upper bridge 6. A 71 handle 8 is provided on the top.

A fuel tank 9 is provided behind the handle 8, and a seat 10 is provided further behind this 9.

Also, a bracket 1 is attached to the body frame 2 at the lower center of the vehicle body.
A front end of a rear fork 13 which rotatably supports a rear wheel 12 is pivotally attached to the rear end of the rear fork 1 through a rear fork 1 .

On the other hand, a V-type engine 14 is mounted on the vehicle body frame 2, and this engine 44 has two front and rear cylinders (22) 16.1" r on the crankcase 15, each having a V-shaped side surface that is inclined diagonally in the front and rear directions. It is equipped with

From the front cylinder unit 16 to the cylinder, a front exhaust pipe 18 extends downward from the front of the cylinder unit 16 and backward, and curves backward so as to pass under the side of the crankcase 15. As shown in Figure 2, it is connected to the front left side of the assembly channel 19. On the other hand, a rear exhaust pipe 20 hangs down substantially linearly from behind the rad cover 171L and downward to the cylinder of the rear cylinder unit 17, with its upper part bent slightly, and connects to the collection chamber 19 via a joint 21 midway. As shown in FIG. The pipe length is front exhaust pipe 1
It is set equal to that of 8.

By the way, an exhaust muffler 22.22 is connected to the left and right rear of the exhaust pipe 19, which is formed by connecting two exhaust pipes 18.20 to the left and right of the front.
Exhaust gas generated at the front and rear exhaust pipes 18.20 merges into the collecting channel (19), from which it is further branched by the left and right mufflers 22.22, and finally reaches the rear end opening of the muffler 22.22. is emitted into the atmosphere.

Since the rear exhaust pipe 20 is bent outside the collection chamber 19 and connected to it as described above, it is possible to reduce the number of bent parts of the exhaust pipe 20, and the radius of curvature of each bent part can be reduced. This can be set to a large value, thereby reducing the flow resistance of the exhaust gas flowing therethrough, that is, the bending loss. As a result, exhaust resistance is reduced,
A decrease in the output on the rear cylinder unit 17 side is avoided, the outputs of the two cylinders 16 and 17 are kept balanced, and smooth operation of the engine 14 is guaranteed. Furthermore, both exhaust pipes18.
Since the lengths of the pipes 20 are the same, it is possible to effectively utilize the pulsation effect and improve the engine output as before.

Furthermore, since the rear exhaust pipe 20 and the rear exhaust pipe 19 can be easily assembled via the joint 21, the assembly work can be improved.

As is clear from the above description, according to the present invention, the exhaust pipe on the rear cylinder side of the V-type engine is bent outside the collecting chamber and connected to the channel, thereby reducing the number of bent parts of the exhaust pipe. At the same time, the radius of curvature of the bent portion can be set large, and exhaust resistance can be minimized to prevent a decrease in engine output.

Since the above-mentioned carbon dioxide is used, the assembly of the exhaust pipe and the collecting chamber can be simplified, thereby contributing to improving the efficiency of assembly work.

[Brief explanation of drawings]

The drawings show one embodiment of the present invention, and FIG. 1 is an overall side view of a motorcycle equipped with an exhaust system according to the present invention, and FIG. 2 is a plan view of a collection chamber portion of the exhaust system. be. In the drawing, 14 is a V-type engine, 16.17 is a front cylinder unit and a rear cylinder unit, respectively, 18.20 is a front exhaust pipe and a rear exhaust pipe, respectively, 19 is a collection chamber, and 2
2 is an exhaust muffler. Patent applicant Honda Motor Co., Ltd. agent Patent attorney 2 1) Prompt question Patent attorney Kunihiko Ohashi Procedural amendment (
Spontaneous) April 6, 1980 Director General of the Japan Patent Office Shima 1) Haruki Tono1, Indication of the case Japanese Patent Application No. 1137-19822, Title of the invention Exhaust system for V-type motorcycle engine 3, person making the amendment Relationship to the case Patent applicant (532) Honda Motor Co., Ltd. 4, agent (1) The detailed description of the invention in the specification is corrected as follows. B. On page 3, line 15, ``Plan view 1'' is corrected to ``transverse plan view''. B. On the 6th line of page 5, after ``It is.'', ``Also, in front of the collecting chamber 19, an oil pan 23 provided on the lower surface of the crankcase 15 is arranged at approximately the same bottom surface height.'' (2) The brief description of the drawings in the specification is corrected as follows. On page 7, line 5, it says, "This is a plan view.""It is a cross-sectional plan view. Figure 3 is a side view of the same, and Figure 4 is a sectional view taken along line 4-4 in Figure 2." (3) Regarding the drawings, we have corrected Figures 1 and 2 as shown in the attached sheet, and have newly added Figure 3.
Add Figure and Figure 4 0 Figure 2 22 Figure 3 U Figure 4

Claims (1)

[Claims] An exhaust system in which a front exhaust pipe led out to the rear and lower part of the front cylinder unit of a V-type motorcycle engine and a rear exhaust pipe led out to the rear and lower part from the rear cylinder unit merge into a collecting chamber. An exhaust system for a V-type motorcycle engine, characterized in that the rear exhaust pipe is bent outside the collecting chamber and connected to the collecting chamber.