JPH0550580B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a V-type multi-cylinder engine, particularly a V-type multi-cylinder internal combustion engine for vehicles.

Prior Art In order to shorten the engine width in the crankshaft direction of a multi-cylinder internal combustion engine, the cylinder arrangement can be made into a V-shape, but from the perspective of engine balance, the cylinder angle is usually set at a right angle. , the longitudinal dimension perpendicular to the crankshaft direction becomes longer.

Problems to be Solved In order to improve this, a technology was developed to maintain the balance of the engine by appropriately selecting the mounting position of the crank pin, the mounting position of the balance weight, and its mass (Japanese Patent Application No. 177831/1983). However, in order to simplify the engine's air supply system, if the carburetor is placed on the side of the cylinder angle, as the cylinder angle becomes narrower, the carburetor will be placed higher, making the entire engine smaller. It was difficult to do so.

Means and Effects for Solving the Problems The present invention relates to an improvement of a V-type multi-cylinder internal combustion engine that overcomes the above-mentioned difficulties, in which each cylinder is
In a V-type multi-cylinder internal combustion engine in which the front and rear cylinders are arranged so as to substantially overlap in the longitudinal direction of the vehicle body, and the intake ports of each cylinder are arranged on the cylinder angle side, the engine is located outside the front and rear cylinder angle space. A single carburetor common to the front and rear cylinders is disposed at a position where the intake pipe connected to the carburetor is disposed approximately at the center of the cylinder confined space, which is located approximately equidistant from the front and rear intake ports. The present invention is characterized in that intake branch pipes of approximately equal length are connected to one intake pipe branch and are connected from the one intake pipe branch to the intake ports of each of the cylinders.

Since the present invention is configured as described above,
Although the same carburetor is installed between the front and rear cylinders in order to downsize the internal combustion engine, the distance from the front and rear cylinders to the carburetor is the same, and as a result, the intake air between the cylinders is This makes it possible to prevent timing deviations and enables stable engine operation.

In addition, in the present invention, one carburetor common to the front and rear cylinders is disposed at a position away from the front and rear cylinder included angle space, so even if the internal combustion engine has a narrow cylinder included angle, it will not be affected by this narrow cylinder included angle. This allows the height of the intake system to be set lower than when a carburetor is attached to each of the front and rear cylinders between the cylinders, lowering the center of gravity of the car body, and increasing the temperature when it comes into contact with the cylinders and is heated. By preventing heated air from being applied to the carburetor, the carburetor can be maintained at a low temperature, thereby improving intake efficiency and thus engine efficiency and engine output.

Embodiment An embodiment of the present invention illustrated in FIGS. 1 to 4 will be described below.

Reference numeral 1 denotes a tricycle having two front wheels 2 and one rear wheel 3, and a power unit 6 is mounted in the front body 4 of the tricycle 1.

The power unit 6 also includes a front and rear V-type two-cylinder internal combustion engine 7 whose cylinder angle is set to an acute angle of 90° or less and whose engine is balanced, and which is connected to a crankshaft of the internal combustion engine 7 (not shown). The front wheels 2 are connected to the output shaft 15 of the transmission mechanism, and the output of the internal combustion engine 7 is transmitted to the front wheels 2 at an appropriate rotational speed via the clutch and the transmission mechanism.
The three-wheeled vehicle 1 is now able to travel.

Furthermore, the front cylinder 8a of the front and rear V-type two-cylinder internal combustion engine 7 is moved to the left from the center in the width direction of the engine 7.
The rear cylinder 8 is offset by
b is offset by A to the right from the center in the width direction, and the cylinders 8a and 8b are arranged symmetrically with respect to the 0 point in FIG. Ports 10a and 10b are provided, respectively, and exhaust ports 11a and 11b are provided on the opposite side.

Furthermore, the front and rear cylinder heads 9a are arranged from the left side of the vehicle body toward the center in the vehicle width direction.
An intake pipe 12 is arranged in the middle of the intake pipe 9b.
The second branch 13 is located at the center point 0 of the groove connecting the intake ports 10a and 10b, and a carburetor 14 is interposed in the intake pipe 12.

In the embodiment shown in FIGS. 1 to 4, since the included angle of the cylinders 8a and 8b is set to a narrow angle of 90° or less as described above, the front and rear dimensions of the V-type two-cylinder internal combustion engine 7 are By shortening the length, the power unit 6 can be made smaller.

Further, in the embodiment, an intake pipe 12 is disposed between the front and rear cylinder heads 9a, 9b, oriented from the left side of the vehicle body toward the center in the width direction of the vehicle body, and a line connecting the intake ports 10a, 10b is provided. The branch part 13 of the intake pipe 12 is arranged at the center point 0,
Since the carburetor 14 is installed in the intake pipe 12, the intake system can be prevented from protruding below the cylinder heads 9a, 9b, and as a result, the bonnet 5 of the front body 4 can be lowered to lower the vehicle height. It can be customized with excellent aerodynamics.

Further, the carburetor 14 is connected to the front and rear cylinders 8a,
Since the cylinders are disposed from the angular space between the cylinders 8b toward the outside of the vehicle body width, the heated air that comes into contact with the cylinders 8a and 8b and rises is prevented from hitting the carburetor 14, thereby keeping the carburetor 14 at a low temperature and improving intake efficiency. As a result, it is possible to improve engine efficiency and engine output.

In the embodiment shown in FIGS. 1 to 4, the intake pipe 12 is oriented toward the left side of the vehicle body from the center point 0 of the line connecting the intake ports 10a and 10b, and in the width direction of the vehicle body. As in, intake port 10
The intake pipe 12 may be directed from the center point 0 of the line connecting a and 10b at a right angle to the same line and toward the rear of the vehicle body. In such an embodiment, the intake pipe 12
The air-fuel mixture that has passed through the front and rear intake ports 10a, 10
b can be equally distributed.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of a tricycle equipped with a multi-cylinder internal combustion engine according to an embodiment of the present invention, Fig. 2 is a side view thereof, Fig. 3 is a side view of the embodiment, and Fig. 4 is a cross-sectional view thereof. The plan view, FIG. 5, is a cross-sectional plan view illustrating another embodiment of the present invention. 1...Auto tricycle, 2...Front wheel, 3...Rear wheel, 4...Front body, 5...Bonnet, 6...
Power plant, 7...Front and rear V-type two-cylinder internal combustion engine, 8...
...Cylinder, 9...Cylinder head, 10, 11
...Intake ports 10, 12...Intake pipe, 13...
Intake pipe branch, 14... Carburetor, 15...
output shaft.

Claims (1)

[Claims] 1. In a V-type multi-cylinder internal combustion engine in which each cylinder is arranged in a V-shape in the longitudinal direction of the vehicle body, the front and rear cylinders are arranged so as to substantially overlap in the longitudinal direction of the vehicle body, and the intake port of each cylinder is arranged on the cylinder included angle side, A carburetor common to the front and rear cylinders is disposed at a position apart from the angular space between the front and rear cylinders, and an intake pipe connected to the carburetor is
The intake pipe is connected to one intake pipe branch located approximately at the center of the cylinder-included space, which is located at approximately the same distance from the front and rear intake ports, and extends from the one intake pipe branch to the intake port of each cylinder with approximately equal length. A V-type multi-cylinder internal combustion engine characterized by a connected intake branch pipe.