JPH0114732Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an exhaust system for a motorcycle, and more particularly, to an exhaust system for a motorcycle equipped with a transverse V-type engine.

Generally, some motorcycles equipped with a multi-cylinder engine have an exhaust structure that collects exhaust gas and discharges it from the viewpoint of vehicle body design, vehicle weight, production cost, and the like. However,
When the exhaust gases are collected, the cylinders interfere with each other, causing the exhaust gas to flow backwards or deteriorate, resulting in a so-called exhaust interference phenomenon, which sometimes reduces exhaust efficiency. Therefore, in a conventional motorcycle equipped with a horizontal V-type engine, as shown in the conceptual diagram of the main parts of the motorcycle 1 and its plan view shown in FIGS. 1a and 1b,
Cylinder heads 2a, 2 of horizontal V-type engine 2
The exhaust pipes 3, 4, 5, and 6 arranged for each of the cylinders b, 2c, and 2d are connected to a chamber body 8 located below the swing arm 7 and between the crankcase 2c and the pivot shaft 7a of the engine 2. connect,
After the exhaust gas is collected in the chamber body 8, it is discharged to the atmosphere through mufflers 9 and 10 connected to the chamber body 8. In this conventional exhaust structure, by connecting the exhaust pipes 3, 4, 5, and 6 to the chamber body 8, which is a rapidly expanding section, pressure fluctuations in the exhaust gas are attenuated by the chamber body 8, and the exhaust pipes 3, 4, 5, 6
This reduces mutual exhaust interference. In addition, the second
The figure is a partially cutaway perspective view showing the exhaust structure of the conventional motorcycle mentioned above, and the same parts as in FIG. 1 are designated by the same reference numerals. In addition, in FIG. 1, the reference numeral 11 indicates the exhaust pipe 3,
4, 5, and 6 to the chamber body 8, respectively.

By the way, in the conventional exhaust system described above, each cylinder head 2 of the horizontal V-type engine 2
Exhaust pipes 3, 4 connected to a, 2b, 2c, 2d,
5 and 6 are all connected to the chamber body 8 formed from one space 8a (FIG. 2),
In particular, exhaust interference between exhaust gases discharged from cylinders whose exhaust timings are close to each other among multiple cylinders cannot be sufficiently reduced even by the chamber body, and therefore, in some rotational ranges of the engine. The disadvantage was that the output decreased.

Furthermore, in a motorcycle equipped with a transversely mounted V-type engine as shown in FIG. Due to the engine layout, it is extremely short, and as a result, a large exhaust pipe volume cannot be secured, making it impossible to effectively utilize exhaust pulsation in the low speed range, reducing exhaust efficiency and making it impossible to increase engine torque in the low speed range. There were also drawbacks.

SUMMARY OF THE INVENTION In view of the above-mentioned problems with conventional exhaust systems, an object of the present invention is to provide an exhaust system that improves the output and low-speed torque of a transverse V-type engine mounted on a motorcycle.

In order to achieve the above-mentioned object, this invention connects the exhaust pipes connected to each cylinder head of a horizontal V-type engine to a single chamber body, and collects the exhaust gas from the engine in the chamber body. In the exhaust system for a motorcycle, the chamber body is defined into an upper space part and a lower space part which are isolated and sealed from each other, and the forward tilting cylinder is disposed in the upper space part. and connect the exhaust pipes of the backward tilting cylinder to the lower space, and connect a muffler that communicates only to the upper space and a muffler that communicates only to the lower space to the lower space. This improves output by eliminating exhaust interference caused by exhaust gas that approaches the exhaust timing of the V-type engine, and increases the exhaust pipe volume by ensuring a longer pipe length for each exhaust pipe of the backward-tilting cylinder. This improves the exhaust efficiency in the low speed rotation range of the transversely mounted V-type engine mounted on the motorcycle, thereby improving the torque in the low speed range.

Hereinafter, one embodiment of the exhaust system for a motorcycle according to the present invention will be described in detail.

3a and 3b are conceptual diagrams of main parts of a motorcycle 1, respectively, showing an exhaust system for a motorcycle according to the present invention;
In the plan view, the same parts as in FIGS. 1 and 2 are designated by the same reference numerals.

In FIGS. 3a and 3b, exhaust pipes 10, 11, 12, and 13 extending from the cylinder heads 2a, 2b, 2c, and 2d of the horizontal V-type engine 2 are located below the swing arm 7 and below the swing arm 7, respectively. Front side 14a
is the chamber body 1 located below the pivot shaft 7a.
4 are connected to each other. Of the exhaust pipes, the exhaust pipe 1 extends from the rearwardly inclined cylinder heads 2c and 2d located at the rear of the V-type engine 2.
2 and 13 are swing arms 7 as shown in FIG.
The pivot shaft 7a and the stem 7b of the swing arm 7 are connected to a chamber body 14 located below the pivot shaft 7a. As shown in FIG. 4, this chamber body 14 has two spaces separated and sealed from each other by a partition plate 15, namely an upper space 14b located above the motorcycle body and a lower space 14b. Lower space part 1 located on the side
It is divided into 4c. On the other hand, the cylinder heads 2a, 2 of the above-mentioned V-type engine 2 (FIG. 3b)
The firing order in b, 2c, and 2d is 2, respectively.
In the order of a → 2c → 2b → 2d → 2a, and the crank rotation angle interval between them is 270° between 2a → 2c,
90° between 2c → 2b, 270° between 2b → 2d,
If the angle is 90° between 2d and 2a, cylinder head 2
Since the ignition interval between cylinder head 2b and cylinder head 2b is short, and the ignition interval between cylinder head 2d and cylinder head 2a is short, the exhaust timing of exhaust pipe 11 and exhaust pipe 12 communicating with these cylinder heads, and the exhaust pipe 10 are The exhaust timings of the exhaust pipe 13 and the exhaust pipe 13 will be close to each other. By the way, the chamber body 1 shown in FIG.
4, the space 14b, 1 formed in the chamber body 14
4c, an exhaust pipe 10 and an exhaust pipe 11 which are separated in exhaust timing from the front side surface 14a of the chamber body 40 communicate with the upper space part 14b, and one end thereof 10a, 11
a is attached to protrude into the upper space portion 14b. Further, the exhaust pipes 12 and 13 have one end 12
a and 13a pass through the upper surface 14d of the chamber body 14,
Furthermore, it passes through the partition plate 15 and communicates with the inside of the space 14c. Note that the upper space 1 of the chamber body 14
4b and the lower space 14c are fitted with mufflers 16 and 17 that communicate only with the respective spaces. Note that one end portions 16a and 17a of these mufflers 16 and 17 are attached to protrude from the rear side surface 14e of the chamber body 14 into the space portion 14b and the space portion 14c, respectively. Therefore, in the above configuration, the exhaust pipes whose exhaust times are close to each other communicate with different spaces formed in the chamber body 14 separately, and the influence of mutual exhaust interference due to exhaust gas whose exhaust times are close to each other is reduced. removed.

Further, as shown in FIGS. 3 and 4, exhaust pipes 1 extending from the rearwardly inclined cylinder heads 2c and 2d
2 and 13 pass above the pivot shaft 7a of the swing arm 7, and further into the lower space 1 of the chamber body 14.
4c, the length of the exhaust pipe becomes longer, and this ensures a large volume of the exhaust pipe for the backward-inclined cylinder head, making it possible to effectively utilize exhaust pulsation in the low rotation range. Therefore, the exhaust efficiency in the low-speed rotation range is improved, and the engine torque in the low-speed rotation range is improved.

As mentioned above, this idea connects the exhaust pipes that guide the exhaust gas whose exhaust timing is close to each other to different spaces among the plurality of spaces formed in the chamber body, and further connects each of the exhaust pipes to each of these spaces. Since the exhaust gas is released into the atmosphere through an independently communicating muffler, interference between exhaust gases that are close to each other during exhaust timing is eliminated, thereby improving exhaust efficiency. The output characteristics of the type engine can be made even flatter and the output can be increased. In particular, the chamber body is defined into an upper space part and a lower space part, and a horizontal V
The exhaust pipe extending from the rearward-tilting cylinder head of the type engine is connected via the upper part of the pivot shaft of the swing arm, so the length of the exhaust pipe extending from the rearward-tilting cylinder head is longer than before. Therefore, it is possible to expand the exhaust pipe volume and effectively utilize the exhaust pulsation in the low speed range, thereby improving the torque of the transversely mounted V-type engine installed in a motorcycle, especially in the low speed range. I can do it.

[Brief explanation of drawings]

Figures 1a and b are a conceptual front view and a plan view of a motorcycle showing a conventional exhaust system for a motorcycle, respectively, and Figure 2 is a partially cutaway perspective view showing the main parts of a conventional exhaust system for a motorcycle. Figures 3a and 3b are a conceptual front view of a motorcycle showing an exhaust system for a motorcycle according to the present invention, and a plan view thereof, respectively;
FIG. 4 is a partially cutaway enlarged perspective view showing the main parts of the exhaust system for a motorcycle according to the present invention. 1... Motorcycle, 2a, 2b... Forward tilting cylinder head, 2c, 2d... Backward tilting cylinder head,
10, 11, 12, 13... Exhaust pipe, 14... Chamber body, 14b... Upper space part, 14c... Lower space part,
16, 17...muffler.

Claims (1)

[Claims for Utility Model Registration] A plurality of forward-slanting cylinder heads that slope toward the front of the vehicle body and whose ignition timings are separated from each other, and a plurality of backward-slanted cylinder heads that slope toward the rear of the vehicle body and whose ignition timings are separated from each other. It is equipped with a horizontally mounted V-type engine having a horizontal V-type engine, and the exhaust pipes connected to each cylinder head are connected to a single chamber body disposed below the swing arm, and the exhaust gas from the engine is collected in the chamber body. In the exhaust system for a motorcycle, the exhaust gas is discharged from the chamber body to the atmosphere via a muffler, wherein the chamber body is separated into an upper space section located above and a lower space section located below with respect to the vehicle body. The cylinder head is hermetically defined, and only the exhaust pipes of the forward tilting cylinder head are connected to the upper space, and only the exhaust pipes of the rearward tilting cylinder head are connected to the lower space beyond the pivot shaft of the swing arm. An exhaust system for a motorcycle, characterized in that a muffler that extends downward from a position and is connected to the chamber body, and a muffler that communicates only with the upper space and a muffler that communicates only with the lower space. Device.