JP2594478B2 - V-type engine intake system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an intake device for a V-type engine.

[0002]

2. Description of the Related Art In a V-type engine, it is general to arrange an intake system in a space between two cylinder banks. In this case, it is common to arrange the carburetor at the center and connect the end of the intake pipe distributed to each of the left and right banks to the facing surface between the two cylinder heads or the end surface in the crankshaft direction. is there.

[0003]

When an intake port is provided between the two cylinder heads, the opening of the intake port is located at a position deviated in the crankshaft direction with respect to the cylinder center due to the arrangement of the valves. I have no choice.
On the other hand, the carburetor is preferably provided on the non-output side of the crankshaft in consideration of its maintainability.

[0004] From these facts, in the case of a V-type engine,
The carburetor inevitably protrudes in the direction of the crankshaft,
It was difficult to reduce the overall size of the engine.

[0005] The present invention has been devised to address such a problem, and its main purpose is to promote the downsizing of the engine without impairing the maintainability of the carburetor. It is an object of the present invention to provide an intake device for a V-type engine.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided an intake manifold having ends connected to opposing surfaces between a pair of cylinder banks arranged in a V-shape. The intake device of a V-type engine having a carburetor connected to the center of the intake manifold is curved such that the output side of the crankshaft is convex at the center of the intake manifold, and the carburetor is connected to the recessed side. This is achieved by configuring as follows.

[0007]

According to such a structure, the amount of the carburetor projecting in the crankshaft direction can be reduced while being provided on the side opposite to the output of the crankshaft.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The construction of the present invention will be described below in detail with reference to specific embodiments shown in the accompanying drawings.

FIG. 1 and FIG. 2 show an air-cooled V-type engine constructed according to the present invention. The engine body 1
It has a horizontally disposed crankshaft 2 and a pair of cylinder banks 4a and 4b provided in a V-shape integrally with the crankcase 3. These two cylinder banks 4
Each end of an intake manifold 6 whose central portion is curved so as to protrude toward the output side of the crankshaft 2 is connected to intake ports 5a and 5b that are opened on the inner side surfaces of the head portion at the a and 4b. Have been. And this intake manifold 6
A carburetor 7 is attached to the recessed side in the middle part. The inlet end of the carburetor 7 is connected via an elbow pipe 9 to an air cleaner 8 provided in a portion between the two cylinder banks 4a and 4b above the engine body 1.

A centrifugal fan 10 for cooling the engine is fixed to a shaft end of the crankshaft 2 on the side opposite to the output side. The fan cover 11 is attached so as to cover substantially this side.

In order to efficiently guide the air flow generated by the centrifugal fan 10 around the cylinder block, a scroll shape may be provided to the fan cover. However, in order to equalize the cooling air for the two cylinder banks 4a and 4b. An airflow guide rib 12 is provided upright on the inner surface of the fan cover corresponding to the right bank 4b located on the right side as viewed from the fan side. The ribs 12 provide a scroll shape suitable for the cooling air passage for the right bank 4b. A part of the cooling air obtained by the rotation of the centrifugal fan 10 is guided by the fan cover 11 and is sucked through an air inlet (not shown) provided on the lower surface of the case of the air cleaner 8. ing.

As shown in FIG. 1, the two cylinder banks 4a and 4b are offset from each other in the crankshaft direction, and the left bank 4a is
It is biased away from An operating device 13 for controlling the engine rotation speed is provided at a position adjacent to the end face of the left bank 4a on the fan cover 11 side.

The operating device 13 includes a main operating lever 16 connected to a governor arm 15 connected to a throttle lever 14 of the carburetor 7 and a choke knob 18 connected to a choke lever 17. A centrifugal governor (not shown) inside the engine is provided. In conjunction with the tilting movement of the governor arm 15 attached to the governor shaft 19 connected to the output portion of the motor, the rotation speed set by the main operation lever 16 is set to the same value as the known governor device. It functions to keep it constant according to the load.

The operating device 13 is subassembled on a bracket 20 formed by bending a sheet metal.
The left bank 4a is fixed to the head portion with bolts 21. At the position corresponding to the main operation lever 16, a finger-holding plate 22 for holding a finger during operation to suppress camera shake is provided. As a result, the operation is stabilized, and precise control of the rotation speed can be performed.

In order to reduce the overall size of the V-type engine, it is effective to move the carburetor inside the V-bank as much as possible. However, in consideration of maintainability, the carburetor is completely vaporized inside the V-bank. It is not practical to house the vessel.
In practice, it is desirable that the degree of freedom in setting the position of the carburetor in the crankshaft direction is high. Therefore, in the present invention, the central portion of the intake manifold is curved so that the output side of the crankshaft is convex, and the carburetor is connected to the concave side.

[0016]

As described above, according to the present invention, the carburetor can be immersed in a desired size toward the inside of the two cylinder banks. The protrusion dimension in the crankshaft direction can be reduced. Therefore, a great effect can be obtained in making the configuration of the entire engine compact without impairing the maintainability of the carburetor.

[Brief description of the drawings]

FIG. 1 is a plan view partially showing an air-cooled V-type engine according to the present invention.

FIG. 2 is an elevational view of the air-cooled V-type engine shown in FIG. 1 as viewed from a fan cover side.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Engine main body 2 Crankshaft 3 Crankcase 4a / 4b Cylinder bank 5a / 5b Intake port 6 Intake manifold 7 Vaporizer 8 Air cleaner 9 Elbow tube 10 Centrifugal fan 11 Fan cover 12 Guide rib 13 Operating device 14 Throttle lever 15 Governor arm 16 Main operating lever 17 choke lever 18 choke knob 19 governor shaft 20 bracket 21 bolt 22 finger plate

Claims (1)

(57) [Claims] 1. A V-type engine comprising: an intake manifold having ends connected to opposing surfaces between a pair of cylinder banks arranged in a V-shape; and a carburetor connected to a center portion of the intake manifold. A V-type engine, characterized in that a central portion of the intake manifold is curved so that an output side of a crankshaft is convex, and the carburetor is connected to a concave side of the intake manifold. Intake device.