General Electric Company

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

Ira E Marvin

Andrew A Saunders, Jr

Richard S Beitler

Jack E Cornett

Joseph R Cowgill

Control of a gas turbine engine, suitable for powering an aircraft, is accomplished by varying outlet nozzle cross section and/or a mixing of bypass air with exhaust gas at an inlet to the nozzle. The engine includes a core engine having a combustion chamber and high and low pressure turbines followed by an exhaust plenum. High and low pressure compressors driven by the turbine assembly direct air into the combustion chamber and into a bypass duct. The bypass duct extends from an outlet of the low pressure compressor. Pressure of fluid (air or exhaust) is measured at an inlet to the high pressure compressor, in the bypass duct, and in the exhaust plenum. Ratios of the pressure of the duct pressure or of the pressure at the inlet of the high-pressure compressor, to the plenum pressure are employed in a feedback loop for control of nozzle size, and also of mixing valve position in an alternate embodiment of the invention. The feedback loop includes computation of a desired pressure ratio based on desired power and inlet temperature to the low-pressure compressor.

Pressure-ratio control of gas turbine engine

Method of pressure-ratio control of gas turbine engine

Gas turbine engine thrust is controlled by automatically adjusting compressor rotational speed with novel functions of engine inlet temperature to hold thrust to rated values for varying engine inlet temperature conditions. Furthermore, compressor rotational speed is automatically adjusted as a function of inlet pressure to provide a thrust rating schedule which varies with altitude. Compressor corrected rotational speed is limited through a novel function of engine inlet temerature to protect against turbine overtemperature when the engine inlet temperature exceeds the flat thrust rating point.

Method and apparatus for controlling thrust in 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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Fairfield, OH, United States of America

Ira E Marvin