Rapid thrust response control logic for shaft-driven lift fan STOVL engine
AssigneeUnited Technologies Corporation
InventorsRichard A. Freese, Eric T. Meyers
Life of this patent
Estimating the term…
Abstract
A short take-off and vertical landing (“STOVL”) aircraft has a conventional gas turbine engine that is selectively mechanically connected to a vertically-oriented lift fan by a drive shaft when the aircraft operates in a vertical flight mode. An engine control provides for rapid response thrust control of the lift fan and low rotor spool when the pilot initiates desired changes in thrust. The control achieves the rapid thrust response by varying the inlet guide vanes of the lift fan, together with selective fuel flow scheduling. These variations result in a substantially constant low rotor speed, which facilitates the desired rapid thrust response and corresponding aircraft control.
Claims12
A control system for a gas turbine engine selectively coupled to a device during operation in a predetermined operating mode of an apparatus embodying the gas turbine engine and the device, the gas turbine engine having a burner with fuel being controllably provided thereto, the gas turbine engine also having a compressor and a turbine connected together in a spool, the device having airflow passing therethrough in a controlled manner, the control system comprising:
- means for sensing a parameter indicative of a corresponding operating condition of the engine and for providing a sensed engine signal indicative thereof;
- means for sensing a parameter indicative of a corresponding operating condition of the device and for providing a sensed device signal indicative thereof;
- means, responsive to a desired change in an amount of thrust to be provided for by the engine and the device selectively coupled to the engine during operation in the predetermined operating mode of the apparatus, for providing a desired thrust signal indicative of the desired change in the amount of thrust;
- and
- signal processing means, responsive to the sensed engine signal and to the sensed device signal and to the desired thrust signal, for controlling the amount of fuel provided to the engine and for controlling the amount of airflow passing through the device, wherein the amount of fuel provided to the engine and the amount of airflow passing through the device are both in an amount to keep substantially constant a speed of the compressor and turbine spool, wherein by keeping substantially constant the speed of the compressor and turbine spool the control system provides for relatively rapid response of the engine and device selectively coupled together during operation in the predetermined operating mode of the apparatus to the desired change in the amount of thrust.
A control system for an aircraft selectively operable in a vertical mode of flight and having a gas turbine engine and a lift fan and a control system, the gas turbine engine being selectively coupled to the lift fan during the vertical mode of flight, the gas turbine engine having a burner with fuel being controllably provided thereto, the gas turbine engine also having a compressor and a turbine connected together in a spool, the lift fan having airflow passing therethrough in a controlled manner, the control system comprising:
- first processing means, responsive to a signal indicative of an engine operating parameter and responsive to a signal indicative of a lift fan operating parameter and responsive to a signal indicative of a commanded thrust output of the engine, for controlling the amount of fuel provided to the engine;
- and
- second processing means, responsive to a signal indicative of an engine operating parameter and responsive to a signal indicative of a lift fan operating parameter and responsive to a signal indicative of a commanded thrust output of the engine, for controlling the amount of airflow passing through the lift fan;
- wherein the amount of fuel provided to the engine and the amount of airflow passing through the lift fan are both in an amount to keep substantially constant a speed of the compressor and turbine spool;
- wherein by keeping substantially constant the speed of the compressor and turbine spool the control system provides for relatively rapid response of the engine and lift selectively coupled together during vertical flight of the aircraft to the commanded thrust output of the engine.
Dependencies are inferred from the claim text.