Methods and apparatus for trimming engine control systems
First Claim
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1. A method for controlling an aircraft engine using a control system, the control system including a processor coupled to the aircraft engine, said method comprising the steps of;
- receiving a throttle command from the aircraft;
determining a reference value for a controlled variable from an engine power schedule;
generating a trim output based for the reference value based on current engine conditions;
adding the trim to the reference value to obtain a modified reference value;
comparing the modified reference value to a feedback value; and
determining a commanded fuel flow for a corresponding amount of thrust in response to the controlled variable.
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Abstract
A control system trims a gas turbine engine in real-time to provide a desired amount of thrust. The control system includes a controller coupled to the engine for receiving inputs from the engine regarding a status of the engine. The controller includes a processor and a non-volatile memory coupled to the processor. The processor is programmed to execute control logic. An engine power schedule representing values for a controlled variable is stored in the memory.
45 Citations
17 Claims
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1. A method for controlling an aircraft engine using a control system, the control system including a processor coupled to the aircraft engine, said method comprising the steps of;
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receiving a throttle command from the aircraft;
determining a reference value for a controlled variable from an engine power schedule;
generating a trim output based for the reference value based on current engine conditions;
adding the trim to the reference value to obtain a modified reference value;
comparing the modified reference value to a feedback value; and
determining a commanded fuel flow for a corresponding amount of thrust in response to the controlled variable. - View Dependent Claims (2, 3, 4, 5)
receiving an engine sensor value representing an exhaust gas temperature of the engine; and
receiving an engine sensor value representing a fan speed of the engine.
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4. A method in accordance with claim 3 wherein said step of generating a trim output further comprises the step of using steady-state detection logic and at least one of a look-up table, a curve fit, and a physics model to generate the trim.
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5. A method in accordance with claim 1 wherein said step of generating a trim output further comprises the steps of:
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receiving a thrust demand value;
receiving a thrust estimate value; and
generating a trim in response to the thrust demand value and the thrust estimate value.
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- 6. A control system for controlling an aircraft engine, said control system coupled to the aircraft engine for receiving a reference input from engine sensors coupled to the engine, said control system comprising a schedule memory storing an engine power schedule representing reference values for a controlled variable, said control system configured to generate a trim output for a reference value, said control system further configured to add the trim output to an engine power schedule reference value to produce a commanded fuel flow for a corresponding amount of thrust in response to the controlled variable and the engine sensor values.
- 12. An aircraft engine trim system, said system coupled to the aircraft engine to receive reference inputs from the engine to determine a state of the aircraft engine, said system configured to generate a trim output in response to a thrust demand value and a thrust estimate value, said system comprising a schedule memory for storing an engine power schedule representing reference values for a controlled variable.
Specification