Avco Corporation

Kimball J Rumford

Richard M Norris

George S Hudson

Stanley G Janik

Douglass S Youd

Avi Ben-Porat

Timothy R Warner

A gas turbine engine which includes a starter/generator mechanically coupled thereto and an electric oil pump motor for driving an oil pump is started in a manner which assures a continuous and uninterrupted supply of lubricating oil to the moving components of the engine. According to one method, first and second motor controllers initiate operation of the oil pump motor. Thereupon, the second motor controller is re-directed to initiate operation of the starter/generator and the gas turbine engine itself, after which, the second motor controller again joins the first motor controller to accelerate the oil pump motor up to idle speed. The oil pump motor may then be electrically coupled to the starter/generator for continued operation. In another mode of operation, a second motor controller may not be used at all. In that event, the alternating electric power supply for the vehicle powered by the gas turbine engine may be used as an interim source for controlling the speed of the oil pump motor.

Gas turbine motor drive

A plurality of accessories operatively associated with a gas turbine engine are driven by electric motors. A first motor controller initiates operation of a starter/generator mechanically coupled to the engine. After the engine has been started, the motor controller is used to accelerate other accessory motors at a predetermined rate after which they are each electrically coupled to the starter/generator for continued operation. Throughout this operation, the first motor controller serves as a back up for a second motor controller which is dedicated to the operation of a fuel pump motor. Other modes of operation can be achieved as well by reason of the flexibility provided by motor driven accessories.

Management of electrically driven engine accessories

A universal torque measuring system for hollow drive shafts which automatically compensates for variations in wall thickness exhibited by different drive shafts having the same nominal dimensions. During a calibration procedure, the drive shaft is subjected to a first predetermined torque which causes a certain amount of twist dependent upon its wall thickness. At this time, target indicia are positioned and affixed to the drive shaft to produce an initial phase shift relative to indicia on a reference shaft. Thereafter, when the drive shaft is incorporated into an engine and rotated under load subjecting it to a second predetermined torque less than the first predetermined torque, there is a resulting second phase shift. This second phase shift and the second predetermined torque define a second operating condition of the drive shaft. In turn, the first and second operating conditions define a characteristic relationship between torque and phase shift for the drive shaft. A sensor is positioned to detect deviations in phase shift of the first and second target teeth from the initial phase shift and generates a signal proportional to such deviations. A microprocessor is responsive to the signal from the sensor for automatically deriving a value of torque being experienced by the drive shaft as a function of each such deviation according to the characteristic relationship.

Self-calibrating torque measuring system

A unique anti-icing management system for a gas turbine engine is disclosed according to which, at all times, only the required amount of heat is applied to inlet surfaces of the engine to prevent the formation of ice. Heated air is bled from the compressor discharge for this purpose and the amount of flow of the heated air is adjusted by a uniquely operated solenoid valve under the direction of an electronic control responsive to any one of a variety of meaningful conditions including, but not necessarily limited to, temperature of an anti-iced surface at the inlet to the engine, rotational speed of the engine, and the presence of an ice producing meteorological condition. The solenoid valve assumes only two operable positions, namely, a fully open position and a fully closed position, and is operated in a pulsed fashion to control flow on a time basis, rather than on a percentage-of-opening basis which is the conventional mode of operation. A switching operation or mechanism within the electronic control, such as a microprocessor, is responsive to any of the aforementioned conditions to cause the solenoid valve to pulsate according to a predetermined pattern which assures a minimally sufficient flow rate of heated air to the regions to be heated.

Method of operating anti-icing valve

Anti-icing valve

An anti-icing management system for a gas turbine engine according to which, at all times, only the required amount of heat is applied to inlet surfaces of the engine to prevent the formation of ice. Heated air is bled from the compressor discharge, or from some other suitable heat source, for this purpose. The amount of flow of the heated air is adjusted by an electronic control responsive to the temperature of the anti-iced engine inlet surfaces directly in the path of incoming air. The electronic control may be effective to admit flow of the heated air to the region to be heated when a separate ice detector determines the presence of ice and so informs the control.

Anti-icing management system

A simple continuity circuit is provided interconnecting the connector bodies of a wiring harness which directs the signal from the computer control of a gas turbine engine to the fuel metering unit of said engine. The continuity circuit forms part of the ignition exciter circuit and acts to de-energize the exciter when the wiring harness is not in place. This prevents ignition when the failure mode of the fuel metering unit is directing a fuel flow to the combustor which is excessive for safe start-up.

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Fairfield, CT, United States of America

Kimball J Rumford