General Electric Company

The United States of America As Represented by the Administrator of the

George W Bennett

Neil Walker

Paul D Collopy

Sridhar Adibhatla

Matthew William Wiseman

Frederick J Sellers

Richard S Beitler

Stanley G Day

Steven A Merrell

Michael J Sum

A control system trims a gas turbine engine in real-time to provide a desired amount of thrust. The control system includes a controller coupled to the engine for receiving inputs from the engine regarding a status of the engine. The controller includes a processor and a non-volatile memory coupled to the processor. The processor is programmed to execute control logic. An engine power schedule representing values for a controlled variable is stored in the memory.

Methods and apparatus for trimming engine control systems

A speed and phase sensor counterrotates aircraft propellers. A toothed wheel is attached to each propeller, and the teeth trigger a sensor as they pass, producing a sequence of signals. From the sequence of signals, rotational speed of each propeller is computer based on time intervals between successive signals. The speed can be computed several times during one revolution, thus giving speed information which is highly up-to-date. Given that spacing between teeth may not be uniform, the signals produced may be nonuniform in time. Error coefficients are derived to correct for nonuniformities in the resulting signals, thus allowing accurate speed to be computed despite the spacing nonuniformities. Phase can be viewed as the relative rotational position of one propeller with respect to the other, but measured at a fixed time. Phase is computed from the signals.

Propeller speed and phase sensor

The invention concerns a control for an aircraft propeller. During operation in reverse pitch, as occurs upon thrust reversal during a landing maneuver, the speed of the propeller is controlled by adjusting pitch of the propeller, in order to prevent overspeeding. Further, during the transition period while the propeller is converting from forward pitch to reverse pitch, the propeller presents a light load to the engine. At this time, fuel flow to the engine is limited in order to restrict delivery of energy to the propeller, again, for the purpose of preventing overspeeding.

Aircraft propeller speed control

An integrated control system for coaxial counterrotating aircraft propulsors driven by a common gas turbine engine. The system establishes an engine pressure ratio by control of fuel flow and uses the established pressure ratio to set propulsor speed. Propulsor speed is set by adjustment of blade pitch.

Aircraft thrust control

Clearance control means is provided for a gas turbine engine. In one embodiment relating to compressor blade clearance, means is provided for developing a first signal representative of the actual compressor casing temperature, a second signal representative of compressor inlet gas temperature, and a third signal representative of compressor speed. Schedule means is provided for receiving the gas temperature and compressor speed signals and developing a schedule output signal. The schedule output signal is representative of a reference casing temperature at which a predetermined compressor blade stabilized clearance is provided. Means is provided for comparing the actual compressor casing temperature signal and the reference casing temperature signal and developing a clearance control signal representative of the difference therebetween. The clearance control signal is coupled to a control valve which controls a flow of air to the compressor casing to control the clearance between the compressor blades and the compressor casing. Means is provided for modification of the clearance control signal to accommodate transient characteristics. Other embodiments are disclosed.

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Cincinnati, OH, United States of America

George W Bennett