Internal-combustion engines – Charge forming device – Crankcase vapor used with combustible mixture
Reexamination Certificate
2000-08-31
2001-08-28
McMahon, Marguerite (Department: 3747)
Internal-combustion engines
Charge forming device
Crankcase vapor used with combustible mixture
Reexamination Certificate
active
06279555
ABSTRACT:
TECHNICAL FIELD
This invention relates generally to engines, and more particularly to removing oil vapor and/or reclaiming oil from engine crankcase blow-by.
BACKGROUND ART
Potentially harmful pollutants are often produced within a crankcase of an internal combustion engine during operation. These pollutants are present in combustion waste gases, known as “blow-by” gases, that leak past the engine piston rings into the crankcase, where they mix with air that usually includes oil vapor from the engine.
These gases must be allowed to leave the crankcase, to prevent oil vapor from leaking back past the piston rings. The gases increase pressure in the crankcase if left therein. The excess pressure can cause seals to leak and affects normal engine operation in a negative manner.
If the blow-by is merely vented through a road draft tube for example into the atmosphere, the pollutants contribute to air pollution, and engine oil is lost as well.
An alternative approach in handling blow-by has been to pass it through a positive crankcase ventilation (PCV) valve into the intake manifold for recombustion in the engine's combustion chamber, in response to a changing pressure within the crankcase. This can cause different pollutants to be generated by the engine, which also contributes to air pollution. In addition, diverting blow-by into the intake system causes the oily mixture to stick along the walls of the intake manifold and head. Additionally, the oily mixture can cause valve fouling.
Various solutions have been tried. One approach is to route blow-by gases through a filter to remove oil in the oil vapor and other pollutants, such as taught in U.S. Pat. No. 5,722,376 to Sweeten for example. The filter must be periodically changed, however, and oil is lost when the used filter is discarded.
This invention is directed to addressing one or more of the above concerns.
DISCLOSURE OF THE INVENTION
In a first aspect of the invention, a blow-by gas evacuation and oil reclamation system includes an engine compartment, a pump, and an oil separation chamber. The engine compartment has a pump inlet leading to the pump. The pump has a pump outlet leading to the oil separation chamber. The oil separation chamber includes an oil vapor separator, a gas outlet, and a liquid outlet leading to the engine compartment.
In another aspect of the invention, a blow-by gas evacuation and oil reclamation method for an engine includes routing oil-laden air from a crankcase of the engine to an oil separation chamber; separating the oil-laden air into separated oil and separated air that is cleaner than the oil-laden air; and returning the separated oil to the crankcase.
In yet another aspect of the invention, a method for reclaiming oil and evacuating blow-by gases from an engine compartment includes evacuating engine air from the engine compartment, the engine air including a mixture of the blow-by gases and oil vapor; cleaning the evacuated engine air, including reclaiming liquid oil from the evacuated engine air by removing oil vapor from the engine air, resulting in cleansed air having a reduced oil vapor content; diverting the cleansed air to be reused in engine combustion; and diverting the reclaimed liquid oil to an oil receptacle and using the reclaimed liquid oil to lubricate the engine.
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Crowell Thomas J.
Wilson Douglas E.
Bram Eric M.
Caterpillar Inc.
McMahon Marguerite
Roberson Keith P.
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