JPH0243887B2 - - Google Patents

Description

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

In motorcycles equipped with V-type engines, the cylinders protrude in different directions, so
Unlike parallel multi-cylinder engines, it is difficult to concentrate the carburetors in one place, and conventionally the carburetors are arranged close to each other for each cylinder. As a result, there are various restrictions in terms of space layout, and it is difficult to equalize the intake resistance, which causes variations in the output between the front and rear cylinders.When installing an air cleaner, the connection route with the air cleaner becomes complicated, or the connection path with the carburetor becomes difficult. There were problems such as the need to install multiple air cleaners. A vehicle in which a carburetor is disposed between a front cylinder and a rear cylinder has also been proposed, but in this case, the carburetor faces toward the front of the vehicle body and is susceptible to the influence of traveling wind pressure due to differences in traveling speed.

The present invention has been devised in view of the above-mentioned circumstances, and an object of the present invention is to concentrate the carburetor in a V-type engine in one place without being affected by the influence of strike direction wind pressure, and to improve the suction pressure. To provide an intake system for a motorcycle equipped with a V-type engine, which can equalize the output of each cylinder, prevent variations in output from each cylinder, and improve engine performance.

In order to achieve the above object, the present invention is a two-cycle crankcase reed valve engine in which the crankshaft is arranged in the vehicle width direction, and the intake passages of the front cylinder and rear cylinder are separated from each other in the crankcase. It communicates with the crank chamber, which is the primary compression chamber, through a reed valve.
The vehicle is characterized in that the rear cylinders have respective openings facing toward the rear of the vehicle body on the rear side, and a carburetor is connected to each of the openings.

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

FIG. 1 shows a left side view of the motorcycle, and FIG. 2 shows an enlarged left side view of the engine.

The body frame 2 of the motorcycle 1 includes a head tube 3 at the front end, and the front fork 4 that supports the front wheel 5 in a freely steerable manner has a top and a bottom bridge 4.
a, 4b to the head tube 3, and above the front fork 4 there is a handle 6.
will be established.

The body frame 2 includes a main tube 11 extending rearward from the upper end of the head tube 3, a subtube 12 extending rearward from the lower end, and a down tube 13 extending downward from the subtube 12.
A down tube blower 14 extends rearward from the lower end of the down tube blower 13, a center tube 15 extends diagonally upward from the rear end of the down tube blower 14 and connects to the main tube 11, and the main tube 1
A seat rail 16 extending rearward from the middle portion of
Consists of etc.

A rear fork 22 supporting a rear wheel 21 is pivotally supported by the center tube 15, a chamber cover 23 is provided over the main tube 11, and a seat 24 is placed on the seat rail 16.

The main tube 11, the sub tube 12,
Down tube 13, down tube blower 14,
An engine 31 is mounted in the space surrounded by the center tube 15, and in the embodiment, it is a V-type two-stroke engine with a horizontal crankshaft and two cylinders in the front and rear, and the engine output is transmitted to the rear wheels 21 by a chain drive. do.

The front cylinders 32, 32 and the rear cylinders 33, 33 are, as shown in Figs. 3 and 4, cylinder blocks 36 and 36, respectively, which are attached to a crankcase 34 and have a cylinder 35 formed therein.
a cylinder head 3 fitted with a plug 37;
The front cylinders 32, 32 protrude diagonally forward of the vehicle body, the rear cylinders 33, 33 protrude diagonally upward, and each cylinder 35 is fitted with a piston 39, respectively. .

The crank case 34 has the cylinder 35
Crank chambers 41 are respectively defined corresponding to the respective crank chambers 41, and a crank shaft 42 is provided by passing through each crank chamber 41, and a crank pin 43 and left and right crank webs 44, 4 are provided.
4 is housed in each crank chamber 41, and the piston 39 and crank pin 43 are connected by a connecting rod 45.

As shown in FIG. 5, the cylinder block 36 and crankcase 34 are provided with scavenging passages 46 and 4 so as to communicate each cylinder 35 with the crank chamber 41.
As shown in FIG. 3, the cylinder block 36 forming the front cylinder 32 has an exhaust passage 47 that communicates with the cylinder 35 and opens diagonally upward.
As shown in FIG. 4, an exhaust passage 47 is formed which communicates with the cylinder 35 and opens diagonally forward.

Furthermore, an intake passage 51 is provided in the crankcase 34.
will be established.

As shown in FIGS. 3 to 5, the intake passage 51 extends obliquely upward at the rear of the vehicle body, and its front end is defined between the left and right crank webs 44, 44 in each crank chamber 41. It is opened to face the space 52, and its rear end is opened 53 diagonally rearward behind the rear cylinder 33, and connected to the rear end opening 53 to mount a carburetor 54.

In the rear end opening 53 of the intake passage 51, there is a reed valve 5 that opens and closes the intake passage 51 according to pressure changes in the crank chamber 41 and restricts backflow of the air-fuel mixture.
5, and the valve body 56 of the reed valve 55 is formed to open and close along the substantially axial direction of the crankshaft 42.

In addition, 61 in the drawing is an exhaust pipe.

Since the present invention is configured as described above, the carburetor 54 connected to the front and rear cylinders 32, 32, 33, 33...
can all be arranged centrally on the rear side of the rear cylinder 33,
This is extremely advantageous in terms of space layout compared to the conventional arrangement of individual carburetors for each cylinder, and space efficiency can be increased by using multiple carburetors.

In addition, since the carburetor 54 can be concentrated on the rear side of the rear cylinder 33 and can be disposed toward the rear, it is less susceptible to the influence of strike wind pressure due to differences in traveling speed, and the suction pressure can be equalized for each cylinder 32, 32, It is possible to prevent variations in the output between 33 and 33.

Also, when installing the air cleaner 62, the first
As shown by the imaginary lines in the figure, only one air cleaner 62 is required, and the connections between the air cleaner 62 and each carburetor 54 can be made simple and uniform, and each cylinder 32, 32, 3
The engine performance can be improved by equalizing the outputs at 3 and 33.

Also, the valve body 56 of the reed valve 55 is connected to the crankshaft 4.
Since the crank webs 44, 44 in the crank chamber 41 are formed to open and close in the axial direction of the crank chamber 41,
The space 52 between can be effectively used as a suction passage,
The flow of the air-fuel mixture can be further smoothed, and the lateral width of the engine 31 can be reduced without being restricted by the width of the valve body 56.

In the embodiment, the cylinder 35 and the carburetor 54 are
Although the case where the cylinder 35 and the carburetor 54 are communicated with each other via the suction passage 51 and the crank chamber 41 has been described, the present invention can be similarly applied to the case where the cylinder 35 and the carburetor 54 are directly communicated with each other through a suction pipe or the like. Further, in the embodiment, a four-cylinder engine has been described, but the present invention can be similarly applied to an engine with two or more cylinders.

As is clear from the above explanation, according to the present invention, the carburetor in a V-type engine can be concentrated in one place without being affected by the influence of wind pressure in the direction and direction due to differences in running speed, so that the output of each cylinder varies. It has a number of excellent effects, such as preventing this and improving engine performance, and making it possible to connect to the air cleaner easily and evenly.

[Brief explanation of the drawing]

Figure 1 is a left side view of the motorcycle, Figure 2 is an enlarged left side view of the engine, Figure 3 is a sectional view of the engine along the front cylinder, Figure 4 is a sectional view of the engine along the rear cylinder, FIG. 5 is a developed view of the engine showing the relationship between cylinders, intake passages, etc. In the drawing, 31 is the engine, 32 is the front cylinder, and 33 is the engine.
34 is a rear cylinder, 34 is a crankcase, 35 is a cylinder, 46 is a scavenging passage, 47 is an exhaust passage, 51 is an intake passage, and 54 is a carburetor.

Claims (1)

[Claims] 1. In an intake system for a motorcycle equipped with a V-type engine that has cylinder portions connected to a carburetor through intake passages in the longitudinal direction of the vehicle body, the V-type engine has a crankcase reed with a crankshaft arranged in the width direction of the vehicle. It is a valve type two-stroke engine, and the intake passages of the front cylinder and the rear cylinder are connected to the crank chamber, which is an independent primary compression chamber in the crankcase, through a reed valve, and the intake passages of the front cylinder and the rear cylinder are connected to the crank chamber, which is an independent primary compression chamber, through a reed valve. An intake system for a motorcycle equipped with a V-type engine, characterized in that each opening faces toward the rear of the vehicle body, and a carburetor is connected to each of the openings.