Fuel control system for gas turbine engine

Claim 2

A fuel control system for a gas tubine engine comprising: means for generating an actual speed signal proportional to the actual turbine speed of the gas turbine engine; means for generating a scheduled speed signal proportional to a desired engine output power; means for generating a demanded speed signal proportional to the time integral of a difference signal; means for generating said difference signal proportional to the difference between said scheduled speed signal and said demanded speed signal; means for generating an error signal proportional to the difference between said demanded speed signal and said actual speed signal; and means for controlling the fuel flow to the gas turbine engine as a function of said error signal.

Claim 3

A fuel control system as defined in claim 1, further including: means for limiting said difference signal before integration by said demanded signal generating means between an upper limit and a lower limit.

Claim 4

A fuel control system as defined in claim 2 wherein: said upper limit is variable.

Claim 5

A fuel control system as defined in claim 3 wherein: said lower limit is variable.

Claim 6

A fuel control system as defined in claim 1, wherein: said error signal is generated as a function of Wf/Pc where Wf is the fuel flow delivered to the engine; and Pc is the compressor output pressure.

Claim 7

A fuel control system as defined in claim 5, wherein said fuel controlling means includes: means for multiplying said error signal by said pressure signal to yield the fuel flow input to the engine.

Claim 8

A fuel control system for a gas turbine engine of the free turbine type having a gas generator and a power turbine, characterized by: means for generating an actual speed signal proportional to the actual turbine speed of the gas generator of the engine; means for generating a scheduled speed signal proportional to the desired output power of the power turbine of the engine; means for generating a demanded speed signal proportional to the time integral of a difference signal; means for generating said difference signal proportional to the difference between said scheduled speed signal and said demanded speed signal; means for generating an error signal proportional to the difference between said demanded speed signal and said actual speed signal; and means for controlling the fuel flow to the gas generator of the free turbine engine as a function of said error signal.

Claim 9

A fuel control system for a gas turbine engine of the free turbine type having a gas generator and a power turbine, characterized by: means for generating an actual speed signal proportional to the actual turbine speed of the gas generator of the engine; means for generating a scheduled speed signal proportional to the desired output power of the power turbine of the engine; means for generating a demanded speed signal proportional to the time integral of a difference signal; means for generating said difference signal proportional to the difference between said scheduled speed signal and said demanded speed signal; means for generating an error signal proportional to the difference between said demanded speed signal and said actual speed signal; and means for controlling the fuel flow to the gas generator of the free turbine engine as a function of said error signal.

Claim 10

A fuel control system as defined in claim 7, further including: means for limiting said difference signal before integration by said demanded signal generating means between an upper limit and a lower limit.

Claim 11

A fuel control system as defined in claim 8, wherein: said upper limit is variable.

Claim 12

A fuel control system as defined in claim 9, wherein: said lower limit is variable.

Claim 13

A fuel control system as defined in claim 10, wherein: said error signal is generated as a function of Wf/Pc where Wf is the fuel flow delivered to the engine; and Pc is the compressor output pressure.

Claim 14

A fuel control system as defined in claim 11, wherein said fuel controlling means includes: means for multiplying said error signal by said pressure signal to yield the fuel flow input to the engine.

Claim 15

A fuel control system as defined in claim 7 wherein: said power turbine operably powers a rotor of a helicopter.

Claim 16

A fuel control system defined in claim 13, wherein: said rotor speed is substantially constant and wherein said desired output power is demanded as a function of the pitch angle of the rotor.

Claim 17

A fuel control system for a gas turbine engine including an integrator for generating a demanded speed signal which is proportional to the time integral of an acceleration term; means for generating an error signal proportional to the difference between the demanded speed signal and an actual speed signal indicative of the actual speed of the engine; and means for controlling the fuel flow to the engine as a function of said error signal; said fuel control system characterized by: means for generating said acceleration term as the difference between said demanded speed signal and a scheduled speed signal indicative of a desired engine output power.

Claim 18

A fuel control system for a gas turbine engine including an integrator for generating a demanded speed signal which is proportional to the time integral of an acceleration term; means for generating an error signal proportional to the difference between the demanded speed signal and an actual speed signal indicative of the actual speed of the engine; and means for controlling the fuel flow to the engine as a function of said error signal; said fuel control system characterized by: means for generating said acceleration term as the difference between said demanded speed signal and a scheduled speed signal indicative of a desired engine output power.