Aeroengine starter/generator arrangement

• US 8,350,398 B2
• Filed: 10/28/2009
• Issued: 01/08/2013
• Est. Priority Date: 11/28/2008
• Status: Active Grant

• Current Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Original Assignee: Rolls-Royce PLC (Rolls-Royce Holdings Plc)
• Inventors: Butt, David C.
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US12/588,810
• Publication Number:
  US 20100133832A1
• Time in Patent Office: 1,168 Days
• Field of Search: 290/52, 60/391.63, 607/88
• US Class Current: 290/52
• CPC Class Codes: B64C 11/48 Units of two or more coaxial propellers
• CPC Class Codes: B64D 27/026 comprising different types of power plants, e.g. combination of a piston engine and a gas-turbine Hybrid electric aircraft B64D27/33
• CPC Class Codes: F02C 7/275 Mechanical drives
• CPC Class Codes: F02C 7/36 Power transmission arrangements between the different shafts of the gas turbine plant, or between the gas-turbine plant and the power user F02C3/107 - F02C3/13 and F02C7/32 take precedence; couplings for transmitting rotation F16D; gearing in general F16H
• CPC Class Codes: F02K 3/025 the by-pass flow being at least partly used to create an independent thrust component
• CPC Class Codes: F02K 3/072 with counter-rotating , e.g. fan rotors
• CPC Class Codes: F05D 2220/324 to drive unshrouded, low solidity propeller
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

An open-rotor gas turbine engine comprising a starter/generator, a first spool and a second spool, the second spool is of a lower pressure than the first spool; wherein the starter/generator is connected to the first and second spools via first and second clutches respectively. The method of operating the open-rotor engine comprises the step of supplying power to the starter/generator to drive the first spool via the first clutch to start the engine and, once the engine is self-propelling, a step of driving the starter/generator from the second spool via the second clutch to generate electricity.

Claims

1. An open-rotor gas turbine engine comprising a starter/generator, a first spool and a second spool, the second spool is of a lower pressure than the first spool;

wherein the starter/generator is connected to the first and second spools via one-way and oppositely driving first and second clutches respectively, wherein in a starting mode the starter/generator drives the first spool to start the engine and in a generating mode the starter/generator is driven by the second spool to generate electricity.

2. An open-rotor gas turbine engine as claimed in claim 1 wherein the first spool is a low pressure spool and the second spool is a free power turbine spool which drives at least one propeller.

3. An open-rotor gas turbine engine as claimed in claim 1 wherein the engine comprises two contra-rotating propellers.

4. An open-rotor gas turbine engine as claimed in claim 1 wherein the engine comprises a gearbox arranged to connect the clutches to the starter/generator.

5. An open-rotor gas turbine engine as claimed in claim 1 wherein at least one clutch is a sprag-type clutch.

6. An open-rotor gas turbine engine as claimed in claim 1 wherein at least one clutch is electrically controllable via a controller.

7. An open-rotor gas turbine engine as claimed in claim 1 wherein the second spool has a speed range between 1.1 and 2.0.

8. An open-rotor gas turbine engine as claimed in claim 1 wherein the first spool has a speed range between 2.0 and 10.0.

9. A method of operating an open-rotor gas turbine engine comprising a starter/generator, a first spool and a second spool, the second spool is of a lower pressure than the first spool;

wherein the starter/generator is connected to the first and second spools via first and second clutches respectively, wherein the method comprises a first step of supplying power to the starter/generator to drive the first spool via the first clutch to start the engine and, once the engine is self-propelling, a second step of driving the starter/generator from the second spool via the second clutch to generate electricity.

10. A method of operating an open-rotor gas turbine engine as claimed in claim 9 wherein the two clutches are each one-way and oppositely driveable first and second clutches.

11. A method of operating an open-rotor gas turbine engine as claimed in claim 9 wherein the two clutches are each electrically controllable.

12. A method of operating an open-rotor gas turbine engine as claimed in claim 11 wherein the first clutch is engaged during engine starting and is then disengaged once the engine is self-propelling.

13. A method of operating an open-rotor gas turbine engine as claimed in claim 11 wherein the second clutch is disengaged during engine starting and is then engaged once the engine is self-propelling.

14. A method of operating an open-rotor gas turbine engine as claimed in claim 9 wherein the second spool is kept within a speed range between 1.1 and 2.0.

15. A method of operating an open-rotor gas turbine engine as claimed in claim 9 wherein the first spool is kept within a speed range between 2.0 and 10.0.