Internal-combustion engines – Vibration compensating device – Balancing arrangement
Reexamination Certificate
1999-06-30
2001-01-09
Wolfe, Willis R. (Department: 3747)
Internal-combustion engines
Vibration compensating device
Balancing arrangement
Reexamination Certificate
active
06170453
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to the discharge of fluid from a housing without the use of a separate pump. More particularly, the present invention relates to a scavenging system for discharging oil from the interior of a housing through the rotation of at least one balance shaft.
BACKGROUND ART
Fluid pumps such as centrifugal pumps and vane pumps are well known in the art for their ability to pump fluid from one location and transfer it to another location. These pumps are utilized in many conventional structures, including automobiles. Their use in automobiles includes use as oil pumps, fuel pumps and power steering pumps. These pumps all typically utilize their own housing and have a separate fluid inlet, a fluid outlet and a mechanism for drawing fluid into the inlet of the pump and discharging fluid through the outlet of the pump for delivery to a source.
Many automobile engines utilize one or more balance shafts to minimize any noise, vibration, and harshness (“NVH”) generated by the reciprocation of the engine pistons and other engine operations. These balance shafts rotate or counter-rotate within the engine on bearings fed by lubricating oil. These balance shafts are typically located within housings to prevent sump oil from continually flooding the rotating shafts with resultant oil aeration, oil heating, and net losses of engine power. Oil is pumped from an oil pan both to the bearings of the balance shafts and also to the engine, creating an excess of oil within the balance shaft housing. If this excess oil is allowed to build up within the housing, the same problems of aeration of the oil, oil heating, and engine motoring losses will result from repeated contact between the rotating shafts and the residual unscavenged oil.
It is known in the art that discharge openings must be provided to enable the escape of the oil which is fed to the bearings as well as any oil that may have entered the interior of the housing through openings or unsealed joints of the housing. It is also known that the provision of an inlet air opening is beneficial towards creating air flow out of a discharge opening, which in turn aids the flow of discharge oil. Current inlet and discharge openings suffer from a variety of disadvantages in that they do not minimize oil aeration, oil heating, and motoring losses.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an oil scavenging system for the housings of engine balance shafts that minimizes engine oil aeration, oil heating, and power consumption by the balance shafts.
It is a further object of the present invention to provide an oil scavenging system that rapidly purges accumulated oil from the housing interior upon engine startup, thereby minimizing fuel consumption.
It is still a further object of the present invention to provide an oil scavenging system that minimizes or eliminates entry of sump oil into the interior of the housing when the surface of the sump oil becomes elevated, whether by accelerations, vehicle inclination, or engine stoppage.
It is yet another object of the present invention to provide an oil scavenging system that reduces the overall cost of the engine.
In accordance with the objects of the present invention, an oil scavenging system for a vehicle engine's balance shaft housing is provided. The oil scavenging system is for use with a vehicle engine having at least one rotating balance shaft in communication therewith for minimizing engine noise, vibration, and harshness. The at least one balance shaft is disposed within a cavity in the shaft housing. The shaft housing has a top surface, a bottom surface, and side surfaces forming an enclosure for the at least one rotating balance shaft. The shaft housing is typically either secured to the bottom of the engine, or is integral to its cylinder block. The shaft housing has at least one inlet opening formed in the top surface of the housing for drawing air into the shaft housing as the at least one balance shaft rotates. The shaft housing has at least one outlet opening formed in the top surface of the housing such that air and oil are forced out of the shaft housing into the engine as the at least one balance shaft rotates.
REFERENCES:
patent: 4523553 (1985-06-01), Backlund
patent: 4703724 (1987-11-01), Candea et al.
patent: 4703725 (1987-11-01), Weertman
patent: 4741303 (1988-05-01), Kronich
patent: 4766857 (1988-08-01), Lain{acute over (e)}
patent: 5511523 (1996-04-01), Masuda
Ali Hyder
Simpson Industries Inc.
Wolfe Willis R.
LandOfFree
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