V-type engine

Details V-type engine V-type engine

1999-10-20

2001-01-30

Dolinar, Andrew M. (Department: 3747)

Internal-combustion engines

Multiple cylinder

Cylinders radiating

C123S197100, C123S197300, C123S197400

Reexamination Certificate

active

06178932

ABSTRACT:

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a V-type engine including a first bank and a second bank which are disposed in a V-shape on opposite sides of a vertical line passing through the center of a crankshaft carried in a crankcase, the banks being formed continuously with the crankcase, and a first piston and a second piston which are fitted in cylinder blocks of the first and second banks, respectively and which are connected to a common crank pin of the crankshaft through first and second connecting rods, respectively.
2. Desription of the Related Art
Such V-type engines are known, as disclosed, for example, in Japanese Patent Application Laid-open No.61-291734.
Such V-type engine is effective to suppress the entire height of the engine to a low level, while permitting the number of cylinders to be increased by virtue of the inclined attitude of each of the banks, but if the lower portion of the crankcase can be formed at a small depth, the entire height of the engine can be further lowered.
However, a defined amount of oil corresponding to the capacity of the engine is generally stored in the lower portion of the crankcase. For this reason, there is a certain limit to forming the lower portion of the crankcase at a small depth. Especially, when it is desired that the surface of the oil does not contact with a large end of the connecting rod in order to eliminate the loss of power due to the agitation of the oil during rotation of the engine, it is further difficult to decrease the depth of the lower portion of the crankcase.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to ensure that the defined amount of oil stored in the lower portion of the crankcase is not agitated by the large end of the connecting rod, thereby preventing the loss of power, and the lower portion of the crankcase can be formed at a small depth, thereby lowering the entire height of the engine and providing a compactness of the engine.
To achieve the above object, according to a first aspect and feature of the present invention, there is provided a V-type engine including a first bank and a second bank which are disposed in a V-shape on opposite sides of a vertical line passing through the center of a crankshaft carried in a crankcase, said banks being formed continuously with the crankcase, and a first piston and a second piston which are fitted in cylinder blocks of the first and second banks, respectively and which are connected to a common crank pin of a crankshaft through first and second connecting rods, respectively, wherein large ends of the connecting rods, which are connected to the crank pin, are formed so that their lower faces assume a substantially horizontal attitude at a most-lowered position of the crank pin, and a defined amount of oil is stored in a lower portion of the crankcase, so that the oil does not contact with the large ends of the connecting rods.
With the first feature, the large ends of the connecting rods cannot contact with the surface of the oil stored in the lower portion of the crankcase, thereby making it possible to avoid a loss of power due to the agitation of the oil and to contribute to an enhancement in power performance. Moreover, when the crank pin is brought into the most-lowered position, the distance between a horizontal plane tangent to the lowermost end points of the large ends of the connecting rods and the center of the crank pin can be minimized, and the lower portion of the crankcase for storing the defined amount of oil can be formed at a corresponding decreased depth, thereby lowering the entire height of the engine and providing a compactness of the engine.
According to a second aspect and feature of the present invention, each of the large ends is comprised of a large end half formed integrally on a connecting rod body and having a semi-circumferential bearing surface conformed to a semi-circumferential surface of the crank pin, and a cap bolted to the large end half and having a semi-circumferential bearing surface conformed to the other semi-circumferential surface of the crank pin, a joint face between the large end half and the cap being formed in parallel to the lower surface of the large end.
With the second feature, even if the joint face is inclined with respect to an axis of the rod body due to the construction of the large end of the connecting rod, the cap can be maintained in a laterally symmetric shape as in the conventional cap, and the formation and the machining thereof can be achieved easily.
The above and other objects, features and advantages of the invention will become apparent from the following description of the preferred embodiment taken in conjunction with the accompanying drawings.


REFERENCES:
patent: 4656991 (1987-04-01), Fukuo et al.
patent: 5513601 (1996-05-01), Benson
patent: 5537971 (1996-07-01), Pong
patent: 5615642 (1997-04-01), Coughlin
patent: 5941205 (1999-08-01), Hiraoka et al.
patent: 6044818 (2000-04-01), Decuir
patent: 61-291734 (1986-12-01), None

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