US Patent 10393313 Oil circuit of an aircraft engine

An oil circuit of an aircraft engine, includes a tank, a lubricant pump and a recirculation pump. The lubricant pump supplies oil via a supply line from the tank to a load of the engine and to an accessory gearbox. Oil is resupplied via a recirculation conduit to the tank by the recirculation pump. The recirculation conduit is connected to the accessory gearbox via a further recirculation conduit. A valve is provided that can be switched between an open switching state and a closed state. In the open switching state of the valve, oil is supplied to the tank via the recirculation conduit. In the closed state of the valve device, an oil feed to the tank via the recirculation conduit is blocked, and oil from the recirculation conduit is supplied to the accessory gearbox via the further recirculation conduit.