Closed loop fuel control method
First Claim
1. A method for regulating the flow rate of fuel to a gas turbine engine during the initial stages of startup comprising the steps of:
- providing a fuel flow signal, from a preselected schedule, to a function generator that generates a control signal for a fuel control unit that regulates the flow of fuel to said gas turbine engine;
measuring the actual fuel flow from said fuel control unit to said engine, and generating a signal thereof;
producing a first trim signal having a magnitude proportionally related to the magnitude of said measured signal;
combining said measured signal with said scheduled signal to form an error signal;
producing a second trim signal having a magnitude related to the integral as function of time of said error signal;
combining said first and second trim signals to form a third trim signal;
combining said third trim signal with said scheduled signal before said function generator; and
repeating said previous steps until said third trim signal is substantially zero.
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Accused Products
Abstract
A fuel control system for accurately controlling the fuel flow rate to a gas turbine engine during the initial stages of startup is provided. The fuel control system has a novel, closed control loop that measures the actual fuel flow rate to the primary nozzles of the engine, and uses this measurement to trim the commanded fuel flow rate signal generated by preprogrammed schedules in the engine'"'"'s electronic control unit. By the novel arrangement of proportional and integral controllers, the fuel control system maintains a forward path gain of unity while permitting the independent adjustment of the gain of the controllers to achieve the system stability and response necessary for quick correction of fuel flow rate errors.
36 Citations
8 Claims
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1. A method for regulating the flow rate of fuel to a gas turbine engine during the initial stages of startup comprising the steps of:
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providing a fuel flow signal, from a preselected schedule, to a function generator that generates a control signal for a fuel control unit that regulates the flow of fuel to said gas turbine engine; measuring the actual fuel flow from said fuel control unit to said engine, and generating a signal thereof; producing a first trim signal having a magnitude proportionally related to the magnitude of said measured signal; combining said measured signal with said scheduled signal to form an error signal; producing a second trim signal having a magnitude related to the integral as function of time of said error signal; combining said first and second trim signals to form a third trim signal; combining said third trim signal with said scheduled signal before said function generator; and repeating said previous steps until said third trim signal is substantially zero. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8)
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Specification