초록 ▼

A back-up control system is implemented in a single engine aircraft to provide the inactivation of a faulty primary system and engagement of a secondary system, and thereby provide a means of maintaining controllable flight sustaining thrust. The aircraft\s hydromechanical main engine control and it

A back-up control system is implemented in a single engine aircraft to provide the inactivation of a faulty primary system and engagement of a secondary system, and thereby provide a means of maintaining controllable flight sustaining thrust. The aircraft\s hydromechanical main engine control and its companion pressure and temperature sensors can develop faults which can result in the inability of the engine to deliver flight sustaining thrust. The electronic control contains logic functions which indicate failure of the main engine control when all of the following exists for a minimum of three seconds: (a) the power lever is at a position requesting a level of dry thrust which exceeds a predetermned threshold; (b) core engine speed is below that required to deliver the predetermined level of dry thrust; (c) core engine speed is not increasing; and (d) turbine temperature is beneath the maximum allowable limit. The back-up system is used in conjunction with a three position cockpit switch having “normal”, “on”and “standby”positions. In the “normal”position the back-up system is off and must be manually activated by switching to the “on”position. In the “standby” position, the back-up system is automaticlly activated when the necessary conditions occur.

대표청구항 ▼

A back-up control system for use with a single engine aircraft powered by a gas turbine engine, said aircraft being controlled by a main control system which activates a servopiston that adjusts a fuel metering valve which controls a flow of fuel to the gas turbine engine, said back-up control syste

A back-up control system for use with a single engine aircraft powered by a gas turbine engine, said aircraft being controlled by a main control system which activates a servopiston that adjusts a fuel metering valve which controls a flow of fuel to the gas turbine engine, said back-up control system being capable of deactivating the main control system when deteacted faults indicate inadequate control of the gas turbine engine by the main control system, said detected faults including an engine temperature which exceeds a maximum allowable temperature of said gas turbine engine, said back-up control system receiving signals that serve as indications of detected faults from engine sensors which serve as a means for detecting performance characteristics of said gas turbine engine, said performance characteristics including the core engine speed, the gas turbine engine\s temperature, an actual power lever angle, and an acceleration signal which indicates if the gas turbine engine\s core engine speed is accelerating, said back up control system comprising: a comparator which is electrically connected with said engine sensors to receive signals therefrom, said signals including a reading of said engine temperature, a reading of said gas turbine engines actual power lever angle, said gas turbine engine\s core engine speed, and said acceleration signal which indicates when said gas turbine engine\s core engine speed is accelerating in response to acceleration signals commanded by a pilot, said comparator also having a stored set of ideal values including a maximum allowable temperature of said gas turbine engine, power lever angles which are associated with said acceleration signals commanded by the pilot, and target core engine speeds associated with said acceleration signals commanded by the pilot, said comparator outputting a first output signal when said actual power lever angle compares unfavorably with said target power lever angle, said comparator outputting a second output signal when said gas turbine engine\s temperature exceeds said maximum allowable temperature, said comparator outputting a third output signal when the actual core engine speed compares unfavorably with the target core engine speed, and said comparator outputting a fourth output signal when said core engine speed is accelerating; an AND gate having a first, second, third and fourth input terminal which are connected with said comparator to respectively receive said first, second, third and fourth output signals, said fourth input terminal of said AND gate being an inverting input terminal, said AND gate having an output terminal which outputs a fault indication signal; a delay circuit which is electrically connected with said AND gate and receives said fault indication signal therefrom, said delay circuit outputting said fault output signal when said fault indication signal is continuously reproduced by said AND gate for a duration of about three seconds, said delay circuit thereby reporting an actual condition of faults in said gas turbine engine and avoiding a false report based upon transient conditions; a back-up computer which receives said inputs from said engine sensors of said gas turbine engine, said inputs including said gas turbine engines actual core engine speed, compressor discharge pressures and turbine temperature, and said measure of the gas turbine engine\s power lever angle, said back-up computer having a memory loaded with a plurality of correlation schedules including a deceleration schedule which correlates the compressor discharge pressure with a deceleration fuel schedule for the gas turbine engine to indicate a first recommended fuel rate which the back-up computer outputs as a first output signal, said memory having an acceleration schedule which correlates said actual engine core speed with an acceleration fuel schedule to indicate a second recommended fuel rate which said back-up computer outputs as a second output signal, said memory having a fuel metering valve schedule which correlates said gas turbine engine\s actual fuel rate with a position required on its fuel metering valve which said back-up computer uses to produce a rate which it outputs as a third output signal, said memory having a core governing schedule which correlates the power lever angle with the core engine speed, which the computer outputs as a fourth output signal; a control logic circuit which is electrically connected with said computer and to a torque motor amplifier which drives said gas turbine engine\s fuel metering valve, said control logic circuit receiving said first, second, third, and fourth output signals form said computer and producing therefrom an electrical signal which is used by said torque motor amplifier to drive the gas turbine engine\s fuel metering valve, said control logic circuit receiving said first, second, third, and fourth output signals from said computer and producing therefrom an electrical signal which is used by said torque motor amplifier to drive the gas turbine engine\s fuel metering valve and thereby provide control of said gas turbine engine; a switch which is electrically connected with said AND gate and said control logic circuit, said switch having a standby setting in which it automatically activates said control logic circuit and deactivates said main control system when said switch receives said fault output signal from said AND gate, and wherein said switch comprises a three-position switch which has a normal position, a standby position, and an on position, said switch electrically connecting aid main control system with said gas turbine engine such that said back-up control system is inactive when said switch is in the normal position, said switch electrically connecting the back-up system with the gas turbine engine and deactivating the main control system when said switch is in the on position, said switch automatically disconnecting the main control system and connecting in its place the back-up control system when it is in the standby position and when it receives said fault output signal from said AND gate; a means for indicating to a pilot that said detected faults are unacceptable, said indicating means being electrically from said AND gate; and a back-up system selector solenoid operated valve which is activated by said switch, and which connects said control logic circuit to said servopiston which adjusts said fuel metering valve so that said back-up computer controls said flow of fuel to said gas turbine engine when said detected faults indicate inadequate control of the gas turbine engine by the main control system.