HYBRID POWERTRAIN SYSTEM

• US 20140010652A1
• Filed: 07/09/2013
• Published: 01/09/2014
• Est. Priority Date: 07/09/2012
• Status: Active Grant

• Current Assignee: Enedym Inc.
• Original Assignee: Mcmaster University
• Inventors: Suntharalingam, Piranavan, Emadi, Ali
• Granted Patent: US 9,174,741 B2
• Time in Patent Office: Days
• US Class Current: 416/1
• CPC Class Codes: B64D 2027/026 comprising different types of power plants, e.g. combination of an electric motor and a gas-turbines
• CPC Class Codes: B64D 27/02 Aircraft characterised by the type or position of power plants fuselages specially adapted for mounting power plants B64C1/16; wings specially adapted for power plants B64C3/32
• 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: B64D 35/08 characterised by the transmission being driven by a plurality of power plants
• CPC Class Codes: Y02T 50/40 Weight reduction
• CPC Class Codes: Y02T 50/60 Efficient propulsion technologies, e.g. for aircraft

Abstract

A hybrid powertrain for an aircraft may include a drive shaft, the drive shaft, an internal combustion engine to selectably drive the drive shaft, a propeller coupled to the drive shaft and an electric motor having a stator and a rotor and operable to selectably drive the drive shaft. The drive shaft may extend through the electric motor. The rotor may be coupled to the drive shaft to rotate with the drive shaft and the rotor is a flywheel for the internal combustion engine.

Claims

1. A hybrid powertrain for an aircraft, the powertrain comprising.

a) a drive shaft, the drive shaft rotatable about a drive axis;

b) an internal combustion engine to selectably drive the drive shaft;

c) a propeller coupled to the drive shaft;

d) an electric motor having a stator and a rotor and operable to selectably drive the drive shaft, the drive shaft extending through the electric motor, the rotor coupled to the drive shaft to rotate with the drive shaft, the rotor is a flywheel for the internal combustion engine.

2. The powertrain of claim 1, wherein the rotor is between the internal combustion engine and the propeller.

3. The powertrain of claim 1, wherein the electric motor is between the internal combustion engine and the propeller.

4. The powertrain of claim 1, wherein the internal combustion engine comprises an output shaft that is coupled to the drive shaft.

5. The powertrain of claim 4, wherein the output shaft is fixedly coupled to the drive shaft.

6. The powertrain of claim 4, wherein the output shaft is detachably coupled to the drive shaft.

7. The powertrain of claim 6, further comprising a clutch provided between the output shaft and the drive shaft, when the clutch is engaged the output shaft is coupled to the drive shaft and when the clutch is disengaged the output shaft is decoupled from the drive shaft and the drive shaft can rotate relative to the output shaft.

8. The powertrain of claim 1, wherein the electric motor has sufficient power to independently drive the propeller when the clutch is disengaged and the internal combustion engine is not driving the drive shaft.

9. The powertrain of claim 4, wherein the output shaft is coaxial with and rotates about the drive shaft.

10. The powertrain of claim 4, further comprising a first gear mechanism coupled between the output shaft and the drive shaft so that the output shaft rotates at a first speed and the drive shaft rotates at a second speed that is different than the first speed.

11. The powertrain of claim 10, wherein the first gear mechanism comprises a first planetary gear system having a first sun gear driven by the output shaft, a non-rotatable first outer ring gear and at least two first planet gears rotatably mounted on a first planet carrier and disposed radially between the first sun gear and the first outer ring gear, the first planet carrier non-rotatably coupled to the drive shaft.

12. The powertrain of claim 1, wherein the rotor is rotatable relative to the drive shaft and is coupled to the drive shaft via a second gear mechanism, so that the drive shaft rotates at the second speed and the rotor rotates at a third speed that is different than the second speed.

13. The powertrain of claim 12, wherein the second gear mechanism comprises a second planetary gear system having a second sun gear coupled to the rotor, a non-rotatable second outer ring gear and at least two second planet gears rotatably mounted on a second planet carrier and disposed between the second sun gear and the second outer ring gear, the second planet carrier non-rotatably coupled to the drive shaft.

14. The powertrain of claim 1, further comprising a third gear mechanism connecting the propeller to the drive shaft, so that the drive shaft rotates at the second speed and the propeller rotates at a fourth speed that is different than the second speed

15. The powertrain of claim 14, wherein the third gear mechanism comprises a third planetary gear system having a third sun gear driven by the drive shaft, a non-rotatable third outer ring gear and at least two third planet gears rotatably mounted on a third planet carrier and disposed between the third sun gear and the third outer ring gear, the third planet carrier non-rotatably coupled to the propeller.

16. The powertrain of claim 1 wherein the rotor is fixedly and non-rotatably connected to the drive shaft and rotates in unison with the drive shaft.

17. The powertrain of claim 1, wherein internal combustion engine and the electric motor are disposed within a powertrain housing.

18. The powertrain of claim 1, wherein the stator has a stator length in a first direction and the space between the internal combustion engine and the electric motor in the first direction is between about 5% and about 200% of the stator length,

19. The powertrain of claim 1, wherein the electric motor is a starter motor for the internal combustion engine.

20. The powertrain of claim 1, wherein the rotor is the only flywheel in the powertrain.

21. The powertrain of claim 1, wherein the powertrain is operable to drive the propeller at least a takeoff power output when the aircraft is taking off and a cruising power output when the aircraft is cruising, and a maximum power output of the internal combustion engine is less than the takeoff power output.

22. The powertrain of claim 21, wherein the maximum power output of the internal combustion engine is equal to or greater than the cruising power output.

23. The powertrain of claim 21, wherein a maximum power output of the electric motor is less than the takeoff power output.

24. The powertrain of claim 23, wherein the maximum power output of the electric motor is equal to or greater than the cruising power output.

25. The powertrain of claim 1, wherein the internal combustion engine and the electric motor are operable to simultaneously drive the drive shaft.

26. The powertrain of claim 1, wherein the electric motor is configurable in an energized state in which it drives the drive shaft and a non-energized state in which it does not drive the drive shaft, and wherein the rotor rotates with the drive shaft and relative to the stator when the electric motor is in either the energized state or the non-energized state.

27. The powertrain of claim 1, wherein the powertrain is selectably operable in a first configuration in which both the internal combustion engine and the electric motor cooperate to drive the drive shaft, a second configuration in which only the internal combustion engine drives the drive shaft and a third configuration in which only the electric motor drives the drive shaft.

28. A method of operating a hybrid powertrain in an aircraft, the method comprising:

a) driving a propeller with both an internal combustion engine and an electric motor during an aircraft takeoff phase;

b) transitioning from the takeoff phase to an aircraft cruising phase and driving the propeller with only one of the internal combustion engine and the electric motor during at least a portion of the cruising phase.

29-37. -37. (canceled)

38. A method of reducing detectability of an aircraft having a hybrid powertrain, the method comprising:

a) driving a propeller with both an internal combustion engine and an electric motor during a first flight phase in which the powertrain generates a first thermal output;

b) shutting off the internal combustion engine and driving the propeller with only the electric motor during a second flight phase in which the powertrain generates a second thermal output that is less than the first thermal output.