ENGINE CONTROL PARAMETER TRIMMING

• US 20140123625A1
• Filed: 10/02/2013
• Published: 05/08/2014
• Est. Priority Date: 11/05/2012
• Status: Abandoned Application

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: SNELL, Robert John
• Application Number:
  US14/044,182
• Publication Number:
  US 20140123625A1
• Time in Patent Office: Days
• US Class Current: 60/204
• CPC Class Codes: F02C 9/00 Controlling gas-turbine plants; Controlling fuel supply in air- breathing jet-propulsion plants controlling air intakes F02C7/057; controlling turbines F01D; controlling compressors F04D27/00; controlling in general G05
• CPC Class Codes: F02C 9/28 Regulating systems responsive to plant or ambient parameters, e.g. temperature, pressure, rotor speed F02C9/30 - F02C9/38, F02C9/44 take precedence
• CPC Class Codes: F02K 1/18 automatic
• CPC Class Codes: F02K 3/06 with front fan
• CPC Class Codes: F05D 2270/051 Thrust
• CPC Class Codes: F05D 2270/54 by electronic means, e.g. electronic tubes, transistors or IC's within an electronic circuit
• CPC Class Codes: F05D 2270/708 with comparison tables
• CPC Class Codes: F05D 2270/71 synthesized, i.e. parameter computed by a mathematical model

Abstract

A method of re-trimming an engine control parameter. Measure an engine parameter over time. Calculate change in the measured parameter per engine cycle. Determine change of thrust due to the calculated change in the measured parameter from a reference database. Define a new trim value for the engine control parameter that is a function of the change of thrust. Apply the new trim value to the engine control parameter.

Claims

1. A method of re-trimming an engine control parameter of a gas turbine engine comprising steps to:

a measure an engine parameter over time;

b calculate change in the measured parameter per engine cycle;

c determine change of thrust due to the calculated change in the measured parameter from a reference database;

d define a new trim value for the engine control parameter that is a function of the change of thrust; and

e apply the new trim value to the engine control parameter.

2. A gas turbine engine comprising the method as claimed in claim 1.

3. A gas turbine engine as claimed in claim 2 wherein the gas turbine engine comprises two shafts.

4. A gas turbine engine as claimed in claim 2 wherein the gas turbine engine comprises three shafts.

5. A method as claimed in claim 1 wherein the control parameter is selected from the group comprising:

shaft speed;

turbofan power ratio;

engine pressure ratio.

6. A method as claimed in claim 1 wherein the measured engine parameter is selected from the group comprising:

turbine gas temperature;

compressor exit pressure;

total engine temperature;

engine gas temperature;

difference between modelled shaft speed and measured shaft speed.

7. A method as claimed in claim 1 wherein the reference database comprises a graph relating the change of thrust to the calculated change in the measured parameter.

8. A method as claimed in claim 1 wherein the reference database comprises at least one equation relating the change of thrust to the calculated change in the measured parameter.

9. A method as claimed in claim 1 wherein the reference database comprises a look up table and a method to interpolate between values.

10. A method as claimed in claim 1 wherein step 1e comprises applying the new trim value automatically.

11. A method as claimed in claim 1 wherein step 1e comprises applying the new trim value manually.

12. A method as claimed in claim 1 wherein step 1e comprises applying the new trim value in response to the determined change of thrust exceeding a threshold.

13. A method as claimed in claim 1 wherein step 1e comprises applying the new trim value in response to changing an engine component.

14. A method as claimed in claim 13 wherein the engine component comprises a subsystem or module of the engine.

15. A method as claimed in claim 14 wherein the subsystem or module comprises one of the group comprising:

an engine core;

an engine fan assembly;

a compressor module;

a turbine module.