Abstract: An improved gas turbine engine control system maintains a selected level of engine performance despite the failure or abnormal operation of one or more engine parameter sensors. The control system employs a continuously updated engine model which simulates engine performance and generates signals representing real time estimates of the engine parameter sensor signals. The estimate signals are transmitted to a control computational unit which utilizes them in lieu of the actual engine parameter sensor signals to control the operation of the engine. The estimate signals are also compared with the corresponding actual engine parameter sensor signals and the resulting difference signals are utilized to update the engine model. If a particular difference signal exceeds specific tolerance limits, the difference signal is inhibited from updating the model and a sensor failure indication is provided to the engine operator.

Abstract: A converter is provided for transforming the parallel output of a remotely located gas turbine engine parameter sensor into serial form for transmission to an engine control unit. The converter is comprised of an interrogator which operates to sequentially interrogate a plurality of encoder magnetic cores which contain the sensed digital information. The interrogator is comprised of a plurality of magnetic elements, each of which is connected to a corresponding individual encoder magnetic core. The magnetic elements are normally maintained in a saturated state by two electrical current signals which are applied through appropriate biasing circuitry. The current signals and biasing circuitry also act to sequentially unsaturate individual magnetic elements. A high frequency excitation current is also applied to each of the magnetic elements. As each magnetic element unsaturates, an interrogation current generated by the excitation current is transmitted to a corresponding encoder magnetic core.

Abstract: An improved back-up control for use in an aircraft gas turbine engine is presented and includes a fuel control valve adapted to meter the flow of fluid to the gas turbine engine, first means for providing a mechanical position signal indicative of the magnitude of a desired fuel flow change to the engine and second means for limiting the rate at which a change in the signal is transmitted to the fuel control valve thereby limiting the rate of change in fuel flow to the engine. The second means may limit the transmission rate in response to inlet pressure. A variable geometry control valve is provided for varying the position of the variable elements of the gas turbine engine in response to said mechanical position signal and the second means limits the rate at which a change in the signal is received by the variable geometry control valve.

Abstract: An integrated control system for use with a gas turbine engine is provided wherein the control system includes a fuel control valve adapted to meter the flow of fuel to the engine, variable geometry control valve to control compressor variable stators or bleed, back-up control means for providing signals to the control valves and primary control means for providing bias of the signals. Means are provided for biasing the signals during normal mode of operation and the means may be ineffective to bias the signals during failed mode of operation.

Abstract: An electrical connector for applications where reliability and safety are needed uses transformer couplings made in two separable sections. Upon clamping together the surrounding metal housing halves, each inductively coupled pair of transformer windings is enclosed by the associated cup-type ferrite magnetic core to minimize undesired interference and result in good magnetic coupling.