Patent ID: 8485222

Claim:
An engine lubrication system for use in conjunction with an engine, the engine lubrication system comprising: a gearbox; a shaft disposed at least partially in the gearbox; an oil reservoir in flow communication with the gearbox; an oil supply pump in flow communication with the oil reservoir and coupled to the shaft, wherein the oil supply pump is configured to supply oil to the gearbox when the shaft rotates; an oil scavenge pump coupled to the shaft and configured to pump oil from the gearbox to the oil reservoir when the shaft rotates; an oil cooler in flow communication with and disposed between the oil scavenge pump and the oil reservoir; a bypass drain line disposed between the oil reservoir and the oil supply pump; a drain valve disposed in the bypass drain line configured to close when the pressure of the oil discharged by the oil supply pump exceeds a first predetermined pressure, the pressure of the oil discharged by the oil supply pump exceeding the first predetermined pressure as the engine becomes operational; and a first check valve disposed between the oil supply pump and the gearbox, the first check valve configured to open when the pressure of the oil discharged by the oil supply pump exceeds a second predetermined pressure substantially equal to or greater than the first predetermined pressure.