A fuel and oil system comprising a fuel pump; an oil pump. A first electric motor controller configured to supply a variable electrical drive. A second electric motor controller configured to supply a variable electrical drive. A fixed electrical drive. The fuel pump is selectively connected to and driven by the first electric motor controller or the second electric motor controller. The oil pump is selectively connected to and driven by the second electric motor controller or the fixed electrical drive.

A fuel system includes a fuel gathering system in fluid communication with a fuel storage container, and a fluid pump assembly in fluid communication with the fuel gathering system. The fluid pump assembly includes a main gear pump stage and a first flow attenuator. A main driven gear is meshed with a main drive gear in a main pump conduit, and a main pump bearing assembly rotatably supports the main drive gear and the main driven gear. The first flow attenuator is disposed around the main pump conduit, and includes a substantially polygonal fluid opening. Edges of the opening are substantially aligned with an undercut bearing portion on at least one of an inlet side and an outlet side of the main pump conduit to define a non-round fluid boundary.

A fuel system includes a fuel gathering system in fluid communication with a fuel storage container, and a fluid pump assembly in fluid communication with the fuel gathering system. The fluid pump assembly includes a main gear pump stage and a first flow attenuator. A main driven gear is meshed with a main drive gear in a main pump conduit, and a main pump bearing assembly rotatably supports the main drive gear and the main driven gear. The first flow attenuator is disposed around the main pump conduit, and includes a substantially polygonal fluid opening. Edges of the opening are substantially aligned with an undercut bearing portion on at least one of an inlet side and an outlet side of the main pump conduit to define a non-round fluid boundary.

An engine fuel control system is provided, including a supply line for the supply of fuel to a fuel metering valve which controls the flow of fuel to burners of an engine. Fuel is delivered at a first high pressure to the supply line by a pump arrangement. The engine fuel control system includes a restrictor located in the supply line for passage of the fuel delivered by the pump arrangement therethrough. The restrictor is configured such that fuel exiting the restrictor for onward supply to the fuel metering valve is at a second high pressure which is lower than the first high pressure. The engine fuel control system includes pressure limiting valves which actuate when the pressure difference between the first high and low pressure reaches a predetermined level to open a flow path for fuel on the supply line to by-pass the restrictor, thereby limiting the pressure difference.

An engine fuel control system is provided, including a supply line for the supply of fuel to a fuel metering valve which controls the flow of fuel to burners of an engine. Fuel is delivered at a first high pressure to the supply line by a pump arrangement. The engine fuel control system includes a restrictor located in the supply line for passage of the fuel delivered by the pump arrangement therethrough. The restrictor is configured such that fuel exiting the restrictor for onward supply to the fuel metering valve is at a second high pressure which is lower than the first high pressure. The engine fuel control system includes pressure limiting valves which actuate when the pressure difference between the first high and low pressure reaches a predetermined level to open a flow path for fuel on the supply line to by-pass the restrictor, thereby limiting the pressure difference.

An engine fuel system is disclosed for managing drainage of fuel in response to an engine shut-down condition. For normal operation, a piston of a piston assembly is maintained in a first position by pressurized fuel in a volume on a first side of the piston. In response to engine shut-down, pressure is removed from the first side of the piston and fuel in the volume on the first side of the piston is drained into a return conduit that is part of the fuel system's thermal management system. Displacement of the piston in response to removal of pressure on the first side of the piston creates a volume on a second side of the piston for drainage of fuel from a fuel manifold.

An engine fuel system is disclosed for managing drainage of fuel in response to an engine shut-down condition. For normal operation, a piston of a piston assembly is maintained in a first position by pressurized fuel in a volume on a first side of the piston. In response to engine shut-down, pressure is removed from the first side of the piston and fuel in the volume on the first side of the piston is drained into a return conduit that is part of the fuel system's thermal management system. Displacement of the piston in response to removal of pressure on the first side of the piston creates a volume on a second side of the piston for drainage of fuel from a fuel manifold.

A system and method for supplementing fuel feed pressure and flow within an aircraft fuel system. The fuel system includes boost and override fuel pumps delivering fuel from the tanks to a fuel manifold, and a jettison fuel pump. The method includes the steps of: (a) sensing whether the aircraft engine is operating near maximum power; (b) upon sensing the condition, operating the jettison fuel pump in fluid interconnection with the override fuel pump to deliver fuel to the fuel manifold; and (c) upon sensing the cessation of the condition, deactivating the jettison fuel pump. The system includes a monitoring circuit signaling when the aircraft engine speed is greater than a predetermined threshold, and a fuel system control circuit operating a jettison fuel pump enable circuit portion in response to the signal while omitting other jettisoning operations. The jettison fuel pump consequently functions as an override fuel pump assist.

A system and method for supplementing fuel feed pressure and flow within an aircraft fuel system. The fuel system includes boost and override fuel pumps delivering fuel from the tanks to a fuel manifold, and a jettison fuel pump. The method includes the steps of: (a) sensing whether the aircraft engine is operating near maximum power; (b) upon sensing the condition, operating the jettison fuel pump in fluid interconnection with the override fuel pump to deliver fuel to the fuel manifold; and (c) upon sensing the cessation of the condition, deactivating the jettison fuel pump. The system includes a monitoring circuit signaling when the aircraft engine speed is greater than a predetermined threshold, and a fuel system control circuit operating a jettison fuel pump enable circuit portion in response to the signal while omitting other jettisoning operations. The jettison fuel pump consequently functions as an override fuel pump assist.

A fuel pump system for a turbomachine engine can include a boost pump driven by an electric motor and configured to be in fluid communication with a fuel tank, a primary pump configured to be driven by a shaft connected to the turbomachine engine, wherein the primary pump is in fluid communication with the boost pump downstream of the boost pump by a boost branch, a bypass flow branch that connects the boost branch to a downstream branch that is downstream of the primary pump, the downstream branch is in fluid communication with one or more metering valves and/or one or more fuel nozzles, and a bypass valve disposed in the bypass flow branch and/or the downstream branch and configured to selectively directly fluidly communicate the boost branch and the downstream branch.