Reciprocating piston for internal combustion engines

Details Reciprocating piston for internal combustion engines Reciprocating piston for internal combustion engines

1996-05-17

1998-03-24

Kamen, Noah P.

Internal-combustion engines

Cooling

Internal cooling of moving parts; e.g., hollow valves,...

92186, F01P 104

Patent

active

057300909

DESCRIPTION:

BRIEF SUMMARY
BACKGROUND OF THE INVENTION

1. Field of the Invention
The invention relates to an internal combustion engine with at least one cooling oil injector arranged in the motor housing and at least one reciprocating piston made of light metal.
2. The Prior Art
Such an arrangement is known from Soviet Union Patent No. SU-97300. In the piston described therein, both the inlet opening and the outlet opening are stretched in the circumferential direction of the ring-shaped channel. In order to be as long as possible, the stretched openings have to encompass the entire area disposed between the adjacent hubs of the piston. The long-stretched shape of the inlet opening permits the jet of cooling oil to be injected to impact various zones of the piston head during the reciprocating movement of the piston. For this purpose, a cooling air injector injects the cooling oil from the crank space at an angle against the piston head. Due to the reciprocating movement of the piston, the slanted infeed of the cooling oil causes the point of impact to migrate across the entire longitudinal expanse of the inlet opening during the reciprocating movement of the piston. For reasons of symmetry, the outlet opening discharging the cooling oil from the ring-shaped cooling oil channel has the same shape as the inlet opening.
Such prior art pistons suffer from several drawbacks. Because of the large inlet and outlet openings extending on the pressure side and counter-pressure side of the piston across the entire range disposed between the hubs, the prior art piston is not sufficiently strong, especially when the piston is highly stressed. Furthermore, the prior art pistons do not permit adequate cooling of the cooling oil circulating in the cooling channel. To obtain sufficient cooling, the ring-shaped cooling oil channel must be always partially filled. However, a relatively small discharge opening is required to achieve partial filling of the ring-shaped channel space.
DE-AS 1 191 176 shows a piston in which the cooling oil channels are formed by bores extending wind-tilted to the piston axis. There are always two bores connected to each other in the zenith. The bores do not form a cooling oil channel according to the invention. Due to the bores, the shaft and the piston head are weakened. A sharp ridge is formed at the area where the bores run obliquely into each other. The performance of these cooling oil channels, due to the height differences in their course, also differs from the subject matter of the invention. The prior art does not achieve continuous partial filling during operation of the motor, or a shaker effect resulting therefrom, with a respective good heat flow. In addition, the prior art patent restricts the possibility of an optimal position of the cooling channels relative to the surfaces to be cooled, since the bores can only create straight cooling channels.


SUMMARY OF THE INVENTION

The invention deals with the problem of changing the inlet and outlet openings of the reciprocating piston's ring-shaped cooling oil channel so as to achieve an optimal cooling effect from the cooling oil circulating in the ring-shaped channel, while also assuring adequate strength of the piston under high stresses.
The present invention makes it possible to inject a major portion of a jet of cooling oil at an angle into the ring-shaped cooling oil channel. The funnel-like design of the inlet opening leading into the ring-shaped cooling oil channel enables this operation.
With engines whose pistons do not have a closed ring-shaped cooling oil channel, and where the jet of cooling oil is directly aimed at the zenith zone of the interior of the piston skirt, cooling oil jets positioned directly at an angle are used. Due to the angled alignment of the cooling oil jet, the jet impacts different points of the zenith zone due to the reciprocating motion of the piston. In pistons without a closed ring-shaped cooling oil channel, this effect is obtained by having the two opposite hubs of the piston skirt directly impacted at different position

REFERENCES:
patent: 3189010 (1965-06-01), Isley
patent: 5081959 (1992-01-01), Akiyama

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