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

Richard S Beitler

George W Bennett

Ira E Marvin

Frederick J Sellers

Andrew A Saunders, Jr

Jack E Cornett

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.

Control means for a gas turbine engine

An integrated control system for a gas turbine engine of the turbofan type receives signals from a plurality of engine sensors and from the engine operator and generates control signals therefrom. A first control signal regulates the fan exhaust nozzle area in order to control inlet throat Mach number to maintain a low level of engine noise. Additional control signals regulate fuel flow to control engine thrust and fan pitch to control fan speed. A plurality of schedules are utilized to maintain a predetermined relationship between the controlled parameters and a number of fixed and calculated limits can override the control signals to prevent unsatisfactory engine performance.

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Cincinnati, OH, United States of America

Richard S Beitler