Airacraft hydraulic system for improved reliability of integrated hydraulic propulsion controls

摘要

A system (10) is provided for maintaining continuity of hydraulic power from an aircraft engine-driven hydraulic pump (28) to a first set of propulsion control hydraulic loads for controlling the aircraft engine (30). The engine-driven hydraulic pump provides hydraulic power to a second set of airframe hydraulic loads. The engine-driven hydraulic pump has a pump suction (26) having a first pressure and a pump discharge (34) having a second pressure that is greater than the first pressure. The system includes an accumulator (16) coupled to the engine- driven hydraulic pump suction, and the accumulator is chargeable at a third pressure that is less than the first pressure. A relief valve (18) is coupled to the engine-driven hydraulic pump suction, and the relief valve has a relief setpoint at a fourth pressure that is greater than the second pressure. An isolation valve (12) has first ports (36, 38) coupled to the first set of propulsion control hydraulic loads, second ports (46, 50, 54) coupled to the second set of airframe hydraulic loads, and third ports (24, 32) coupled to the hydraulic pump. The isolation valve has a first state and a second state. The isolation valve places the third ports in fluid communication with the first and second ports when the isolation valve is in the first state. The isolation valve isolates the second ports from the third ports when the isolation valve is in the second state, and the isolation valve maintains the first ports in fluid communication with the third ports when the isolation valve is in the second state. The present invention thus maintains a supply of hydraulic fluid to the first set of propulsion control hydraulic loads when the second set of airframe hydraulic loads has been isolated.