JPH0245003B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an exhaust system for a two-wheeled motor vehicle equipped with a V-type engine, and particularly to an exhaust pipe routing structure thereof.

[Prior Art] A V-shaped engine, in which a front cylinder and a rear cylinder are installed vertically in a V-shape on the crankcase, has multiple cylinders but can keep the engine width narrow. A two-wheeled motor vehicle equipped with a type engine has the advantage that the body structure is narrow and compact.

[Problems to be Solved by the Invention] By the way, in a motorcycle equipped with this main V-type engine, the plurality of exhaust pipes extending from the front cylinder and the rear cylinder are guided to the rear of the crankcase, and then Connected to the silencer on the side of the rear wheel.

In this case, if the front cylinder is used as a front exhaust and multiple exhaust pipes are connected to the front of this front cylinder, and the rear cylinder is used as a rear exhaust and exhaust pipes are connected to the rear of this rear cylinder, then Since the rear cylinder is closer to the rear wheel than the front cylinder, the distance from the rear cylinder to the muffler is shorter.

For this reason, the length of the rear cylinder exhaust pipe is shorter than the front cylinder exhaust pipe, so
Discrepancies tend to occur in the output characteristics and performance between the front and rear cylinders, which has the disadvantage of adversely affecting engine performance.

Additionally, since a large number of exhaust pipes pass through both the front and rear sides of the crankcase and are guided below the crankcase, the routing of these exhaust pipes becomes complicated and a large amount of space is required for the exhaust pipes to pass through. be.

The present invention was made based on these circumstances, and it is possible to equalize the pipe lengths of the front exhaust pipe and the rear exhaust pipe, thereby eliminating variations in performance in the output characteristics of the front and rear cylinders. To provide an exhaust system for a two-wheeled motor vehicle, which allows pipes to be easily routed, allows a gathering part of exhaust pipes to be contained within the width of a cylinder, and is compact and well-organized as a whole.

[Means for Solving the Problem] Therefore, in the present invention, a front cylinder and a rear cylinder are erected in a substantially V-shape in the longitudinal direction of the vehicle body on a crankcase housing a crankshaft, and these front cylinders A cylinder and a rear cylinder are provided offset from each other in the axial direction of the crankshaft, and the front cylinder serves as a front exhaust and connects a plurality of front exhaust pipes extending downward to the front surface of the front cylinder. as rear exhaust,
In a two-wheeled motor vehicle, a plurality of rear exhaust pipes extending downward are connected to the rear surface of the rear cylinder, and an output section for extracting engine power is provided on one rear side of the crankcase on the rear cylinder side, A plurality of rear exhaust pipes extending from the rear cylinder are led to a side opposite to the output section at the rear of the crankcase and opposite to the offset direction of the rear cylinder, and are then brought together at the lower rear of the crankcase. The collecting portion is located on the opposite side to the offset direction of the rear cylinder, and the plurality of front exhaust pipes extending from the front cylinder are arranged so that the front of the crankcase is located opposite to the offset direction of the front cylinder. After guiding them to the side, they are brought together below the crankcase, and this gathering part is located on the opposite side to the offset direction of the front cylinder, and the joining part of the front exhaust pipe and the joining part of the rear exhaust pipe are are arranged side by side below the crankcase.

[Function] According to this configuration, the rear exhaust pipe is once led to the opposite side of the output part at the rear of the crankcase, so the length of the rear exhaust pipe from the cylinder to the collecting part is determined by the length of the rear exhaust pipe from the cylinder to the collecting part. This can be secured at the rear of the case, making it possible to lengthen the rear exhaust pipe accordingly. Therefore, the lengths of the front exhaust pipe and the rear exhaust pipe can be equalized, and variations in exhaust pulsation can be eliminated.

Moreover, multiple front exhaust pipes and rear exhaust pipes,
Since each exhaust pipe is assembled below the crankcase, there is no need for many exhaust pipes to intersect in a complicated manner below the crankcase. Therefore, less space is required for the exhaust pipe to be inserted, and the exhaust pipe can be routed easily.

Further, the collecting parts of the front and rear exhaust pipes do not protrude toward the sides of the cylinder, and the collecting parts can be easily accommodated within the width of the cylinder, making it possible to form the entire exhaust system compactly.

[Example] The present invention will be described below based on an example shown in the drawings.

FIG. 1 shows a two-wheeled motor vehicle, in which reference numeral 1 designates a frame constituting a vehicle body, 2 a front fork, 3 a front wheel, 4 a fuel tank, and 5 a seat.

The frame 1 mainly includes a head pipe 6 that supports a front fork 2, a pair of left and right down tubes 7, a main pipe 8, and a back stay 9 (only one of which is shown), and has a double cradle shape as a whole. and,
A bracket 10 (only one of which is shown) is attached to the lower end of the main pipe 8, and between these brackets 10 is pivotally supported the front end of a rear arm 12 which pivotally supports a rear wheel 11.

Further, a water-cooled four-stroke V-type four-cylinder engine 13 is supported on the frame 1 . This engine 13 has a front cylinder 15 and a rear cylinder 16 installed vertically in a V-shape in the longitudinal direction of the vehicle body on the upper surface of a crankcase 14.
A single crankshaft 17 is housed inside the vehicle in a horizontal manner along the left-right direction of the vehicle body. The front cylinder 15 and the rear cylinder 16 are offset along the axial direction of the crankshaft 17, as shown in FIG.

As shown in FIG. 3, on one rear side of the crankcase 13 on the side of the rear cylinder 16, there is a drive sprocket 40 as an output section for extracting engine power.
is provided. A chain 42 is stretched between the drive sprocket 40 and the driven sprocket 41 of the rear wheel 11.

The front cylinder 15 and rear cylinder 16 of the engine 13 are composed of cylinder blocks 18a, 19a having a pair of left and right cylinders, and cylinder head parts 18b, 19b that are covered with the cylinder blocks 18a, 19a. Inlet ports 20 and 21 are provided for each cylinder on opposing surfaces of the cylinder head portions 18b and 19b.

Further, an air cleaner 22, an air flow meter 23, and an intake chamber 24 are arranged between the engine 13 and the fuel tank 4. Four intake pipes 25 are led out from the lower surface of the intake chamber 24, and these intake pipes 25 are connected to the intake ports 20, 21 of the engine 13.

Note that each intake pipe 25 is provided with a fuel injection valve (not shown).

On the other hand, the cylinder head portion 1 of the front cylinder 15
A pair of exhaust ports 2 are provided on the front surface of the cylinder head 8b and the rear surface of the cylinder head portion 19b of the rear cylinder 16, respectively.
6 and 27 are open. Therefore, the front cylinder 15 of the engine 13 has a front exhaust, and the rear cylinder 16 has a rear exhaust.

The pair of exhaust ports 26 of the front cylinder 15 include
Front exhaust pipes 28a and 28b are connected, respectively. The front exhaust pipes 28a, 28b are guided downward from the exhaust port 26, and then passed through the front of the crankcase 14 and guided below the crankcase 14. In the case of this embodiment, the exhaust pipe 28a on the right side in the direction of movement of the vehicle body is directed toward the exhaust pipe 28b on the left side as shown in FIG. The crank case 14 is guided diagonally across the front of the crank case 14. These two front exhaust pipes 28
The lower ends of a and 28b are vertically juxtaposed on the left side of the crankcase 14 as shown in FIG. is being taken around. These front exhaust pipes 28a, 28
The rear end part b is collected into one pipe via a collecting pipe joint 33, and this collecting part 33a is connected to the front cylinder 1.
It is located below the crankshaft 17 on the opposite side to the offset direction of the crankshaft 5.

In addition, the exhaust port 27 of the rear cylinder 16 has
Rear exhaust pipes 32a and 32b are connected, respectively. The rear exhaust pipes 32a, 32b are guided downward from the exhaust port 27, and then passed between the rear surface of the crankcase 14 and the rear arm 12 and guided downward. Of these two exhaust pipes 32a, 32b, especially the rear exhaust pipe 32a on the left side in the direction of movement of the vehicle body.
As shown in FIG. 3, the drive sprocket 4
In order to avoid interference with the engine 0 and the chain 42, it is guided toward the right side of the vehicle body, that is, in the opposite direction to the offset direction of the rear cylinder 16, and diagonally crosses the rear of the crankcase 14. . The lower end portions of the rear exhaust pipes 32a and 32b are arranged front and back on the right side of the crankcase 14, and are routed forward under the crankcase 14, with their front ends connected to the collecting pipe joint 34. It is collected into one book through . A gathering portion 34a of the rear exhaust pipes 32a, 32b is located below the crankshaft 17 on the opposite side of the offset direction of the rear cylinder 16.

Therefore, the gathering part 33a of the front exhaust pipes 28a, 28b and the gathering part 34 of the rear exhaust pipes 32a, 32b are arranged.
a are arranged below the crankcase 14 in the left-right direction of the vehicle body.

An oil pan 2 is located below the crankcase 14.
An exhaust chamber 30 is located behind the exhaust chamber 9. The exhaust chamber 30 has a pair of connection ports 31a, 31 extending forward on both sides of its front end.
b, and these connection ports 31a, 3
1b are located on both left and right sides of the oil pan 29. Then, the front exhaust pipe 2 is connected to the left side connection port 31a.
8a, 28b are connected, and the rear exhaust pipe 32 is connected to the right side connection port 31b.
A gathering part 34a of the parts a and 32b is connected.

Therefore, the front exhaust pipes 28a, 28b and the rear exhaust pipes 32a, 32b are guided below the crankcase 14 through both the front and rear sides of the crankcase 14, where they are connected to a common exhaust chamber 30. There will be.

Note that on both sides of the rear end of the exhaust chamber 30,
A pair of left and right silencers 35 (only one is shown) are connected, and these silencers 35 are located on both left and right sides of the rear wheel 11.

Further, in FIG. 1, reference numeral 36 indicates a radiator supported by the down tube 7, and 37 indicates a shock absorber for suspending the rear arm 12.

According to such a configuration, the two rear exhaust pipes 32a, 3 led out from the rear surface of the rear cylinder 16
2b is led to the rear of the crankcase 14 on the opposite side of the drive sprocket 40 and then routed below the crankcase 14, so the length of the rear exhaust pipes 32a and 32b is determined by the length of the rear exhaust pipes 32a and 32b. 14, and the substantial length of the pipe from the exhaust port 27 to the gathering portion 34a can be increased.

Therefore, the pipe lengths of the front exhaust pipes 28a, 28b and the rear exhaust pipes 32a, 32b can be equalized, eliminating variations in exhaust pulsation and minimizing variations in output characteristics of the front and rear cylinders 15, 16. can be suppressed to

Furthermore, the two front exhaust pipes 28a, 28b and the rear exhaust pipes 32a, 32b are combined into one pipe below the crankcase 14 via the collecting pipe joints 33, 34. Therefore, the large number of exhaust pipes 28a, 28b, 32a, and 32b do not intersect in a complicated manner.

Moreover, in this case, the front and rear exhaust pipes 28a, 28
The gathering parts 33a and 34a of b, 32a and 32b are as follows:
Since it is located on the opposite side to the offset direction of the respective cylinders 15 and 16, these gathering parts 33a and 3
4a does not protrude significantly to the sides of the front and rear cylinders 15, 16 below the crankcase 14, and can be comfortably accommodated within the width of these cylinders 15, 16.

Therefore, the lower part of the crankcase 14 is neatly tied together, which is convenient in terms of appearance, and the exhaust pipes 28a, 28b, 32a, and 32b can be easily routed.

Additionally, an exhaust pipe 28 is provided below the crankcase 14.
a, 28b, 32a, 32b, there is no need to secure a large space for passing these exhaust pipes 28.
There is an advantage that the wires a, 28b, 32a, and 32b can be routed easily.

Note that the engine according to the present invention is not limited to a V-type four-cylinder engine, but can be similarly implemented with a V-type six-cylinder engine, for example, and the cooling method is not limited to a water-cooled type, but may be an air-cooled type.

[Effects of the Invention] According to the present invention described in detail above, the pipe lengths of the front exhaust pipe and the rear exhaust pipe can be made equal, so that
This eliminates variations in exhaust pulsation between the front and rear cylinders, making it possible to equalize their performance and output characteristics.

In addition, there is no need for many exhaust pipes to intersect in a complicated manner under the crankcase, or for the collection part of the front and rear exhaust pipes to protrude significantly to the side of the cylinder. can be easily accommodated.

Therefore, the lower part of the crankcase is neatly connected, and there is no need to secure a space below the crankcase for the exhaust pipe to pass through.
This has the advantage that the exhaust pipe can be easily and easily routed.

[Brief explanation of drawings]

The drawings show an embodiment of the present invention, in which Fig. 1 is a side view of a motorcycle, Fig. 2 is a front view of a V-type engine, Fig. 3 is a rear view of a V-type engine, and Fig. 4 is a side view of a motorcycle.
FIG. 3 is a bottom view of the engine. 1...Vehicle body (frame), 13...Engine, 14
...Crankcase, 15...Front cylinder, 16...
Rear cylinder, 17...crankshaft, 28a, 28
b...Front exhaust pipe, 32a, 32b...Rear exhaust pipe,
33a, 34a...Aggregation part.

Claims (1)

[Claims] 1. On the crankcase housing the crankshaft,
A front cylinder and a rear cylinder are erected in a substantially V shape in the longitudinal direction of the vehicle body, and the front cylinder and rear cylinder are offset from each other in the axial direction of the crankshaft, and the front cylinder is used as a front exhaust. A plurality of front exhaust pipes extending downward are connected to the front surface of the front cylinder, and the rear cylinder is connected to a plurality of rear exhaust pipes extending downward to the rear surface of the rear cylinder as rear exhaust, and In a motorcycle that is provided with an output section for extracting engine power on one side of the rear side of the rear cylinder side of the crankcase, a plurality of rear exhaust pipes extending from the rear cylinder are connected to the opposite side of the output section at the rear of the crankcase. side, and is guided to the opposite side to the offset direction of the rear cylinder, and then gathered at the lower rear of this crankcase, and this gathering part is located on the opposite side to the offset direction of the rear cylinder, and the front The plurality of front exhaust pipes extending from the front cylinder guide the front of the crankcase in the opposite direction to the offset direction of the front cylinder, and then gather together below the crankcase, and connect this gathering part to the front side of the front cylinder. The exhaust of a two-wheeled motor vehicle is located on the opposite side to the offset direction of the cylinder, and the front exhaust pipe collecting part and the rear exhaust pipe collecting part are arranged side by side below the crankcase. Device.