US-12618385-B2 - Hybrid-electric propulsion system equipped with a coupler for switching between modes of operation

Abstract

A propulsion assembly includes a first torque source coupled with a first shaft and a second torque source coupled with a second shaft. A coupler selectively couples the first and second torque sources. When the first and second torque sources are coupled via the coupler, in response to a command to decouple the first torque source, an unloading operation is performed to decrease the torque output provided by the first torque source to a threshold, and when reached, the first shaft is decoupled from the coupler. When the first torque source is coupled with the coupler but the second torque source is not, in response to a command to couple the second torque source, a speed matching operation is performed to increase the speed of the second shaft to match a speed of the first shaft, and when the speeds are matched, the second shaft is coupled to the coupler.

Inventors

• Darek Tomasz Zatorski
• Kurt David Murrow
• Paul Robert Gemin
• Philip M. Cioffi
• John Russell Yagielski

Assignees

• GENERAL ELECTRIC COMPANY

Dates

Publication Date

20260505

Application Date

20230713

Claims (20)

1. 1 . A method, comprising: providing, by a power turbine, a torque output with a power turbine shaft of a gas turbine engine on a coupler mechanically coupled with a propulsor shaft to drive a propulsor; generating, with an electric machine mechanically coupled to the coupler at least partially via an electric machine shaft, an electric power at least partially by the torque output from the power turbine, wherein the coupler includes a transmission shaft that extends along an axis of rotation between a first end at least partially mechanically coupled to the propulsor shaft and a second end at least partially mechanically coupled to the power turbine shaft and the electric machine shaft, and wherein the propulsor shaft, the power turbine shaft, and the electric machine shaft rotate about the axis of rotation; ceasing, in response to a turbine decouple command, generating the electric power with the electric machine; performing, in response to the turbine decouple command, an unloading operation, wherein performing the unloading operation comprises, over an unloading period, increasing a motor torque output provided by the electric machine to increase mechanical power transmission from the electric machine to the propulsor and decreasing the torque output provided by the power turbine on the coupler to decrease mechanical power transmission from the power turbine to the propulsor; and when the torque output provided by the power turbine on the coupler reaches a predetermined threshold, decoupling the power turbine from the coupler.
2. 2 . The method of claim 1 , wherein when the torque output provided by the power turbine on the coupler reaches the predetermined threshold and the power turbine is decoupled from the coupler, the method comprises: providing, by the electric machine, the motor torque output on the coupler to drive the propulsor to a commanded operating point.
3. 3 . The method of claim 1 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased linearly over the unloading period.
4. 4 . The method of claim 1 , wherein in performing the unloading operation, the torque output provided by the power turbine on the coupler is decreased linearly over the unloading period.
5. 5 . The method of claim 1 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased linearly over the unloading period and the torque output provided by the power turbine on the coupler is decreased linearly over the unloading period.
6. 6 . The method of claim 1 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased over the unloading period and the torque output provided by the power turbine on the coupler is decreased over the unloading period so that a net torque provided by the electric machine and the power turbine on the coupler is maintained within a predetermined margin of a commanded torque.
7. 7 . The method of claim 1 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased over the unloading period and the torque output provided by the power turbine on the coupler is decreased over the unloading period so that a net torque provided by the electric machine and the power turbine on the coupler is maintained at a constant torque over the unloading period.
8. 8 . The method of claim 1 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased over the unloading period at a rate and the torque output provided by the power turbine on the coupler is decreased over the unloading period at or substantially at the rate.
9. 9 . The method of claim 1 , wherein decoupling the power turbine from the coupler comprises modulating one or more actuators to move a coupler turbine shaft of the coupler so that torque transmitting features of the coupler turbine shaft disengage from torque transmitting features of the power turbine shaft.
10. 10 . The method of claim 1 , further comprising mechanically decoupling the electric machine from the coupler by modulating one or more actuators to move a coupler electric machine shaft of the coupler so that the coupler electric machine shaft disengages the electric machine shaft.
11. 11 . A controller, comprising: one or more memory devices; one or more processors configured to: cause a power turbine to provide a torque output with a power turbine shaft of a gas turbine engine on a coupler mechanically coupled with a propulsor shaft to drive a propulsor; cause an electric machine mechanically coupled to the coupler partially via an electric machine shaft to generate an electric power at least partially by the torque output from the power turbine, wherein the coupler includes a transmission shaft that extends along an axis of rotation between a first end at least partially mechanically coupled to the propulsor shaft and a second end at least partially mechanically coupled to the power turbine shaft and the electric machine shaft, and wherein the propulsor shaft, the power turbine shaft, and the electric machine shaft rotate about the axis of rotation; cause, in response to a turbine decouple command, the electric machine to cease generating the electric power; cause, in response to the turbine decouple command, an unloading operation to be performed, wherein performing the unloading operation comprises, over an unloading period, increasing a motor torque output provided by the electric machine on the coupler to increase mechanical power transmission from the electric machine to the propulsor and decreasing the torque output provided by the power turbine on the coupler to decrease mechanical power transmission from the power turbine to the propulsor; and when the torque output provided by the power turbine on the coupler reaches a predetermined threshold, cause the power turbine to decouple from the coupler.
12. 12 . The controller of claim 11 , wherein when the torque output provided by the power turbine on the coupler reaches the predetermined threshold and the power turbine is decoupled from the coupler, the one or more processors further configured to: provide, by the electric machine, the motor torque output on the coupler to drive the propulsor to a commanded operating point.
13. 13 . The controller of claim 11 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased linearly over the unloading period.
14. 14 . The controller of claim 11 , wherein in performing the unloading operation, the torque output provided by the power turbine on the coupler is decreased linearly over the unloading period.
15. 15 . The controller of claim 11 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased linearly over the unloading period and the torque output provided by the power turbine on the coupler is decreased linearly over the unloading period.
16. 16 . The controller of claim 11 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased over the unloading period and the torque output provided by the power turbine on the coupler is decreased over the unloading period so that a net torque provided by the electric machine and the power turbine on the coupler is maintained within a predetermined margin of a commanded torque.
17. 17 . The controller of claim 11 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased over the unloading period and the torque output provided by the power turbine on the coupler is decreased over the unloading period so that a net torque provided by the electric machine and the power turbine on the coupler is maintained at a constant torque over the unloading period.
18. 18 . The controller of claim 11 , wherein in performing the unloading operation, the motor torque output provided by the electric machine on the coupler is increased over the unloading period at a rate and the torque output provided by the power turbine on the coupler is decreased over the unloading period at or substantially at the rate.
19. 19 . A propulsion assembly, comprising: a gas turbine engine that includes a power spool having a power turbine and a power shaft mechanically coupled with the power turbine; a propulsor assembly that includes a propulsor shaft mechanically coupled with a propulsor; an electric machine; a coupler; and the controller of claim 11 .
20. 20 . A non-transitory computer readable medium comprising computer-executable instructions, which, when executed by one or more processor of a controller of an aircraft, cause the one or more processors to: cause a power turbine to provide a torque output with a power turbine shaft of a gas turbine engine on a coupler mechanically coupled with a propulsor shaft to drive a propulsor; cause an electric machine mechanically coupled to the coupler partially via an electric machine shaft to generate an electric power at least partially by the torque output from the power turbine, wherein the coupler includes a transmission shaft that extends along an axis of rotation between a first end at least partially mechanically coupled to the propulsor shaft and a second end at least partially mechanically coupled to the power turbine shaft and the electric machine shaft, and wherein the propulsor shaft, the power turbine shaft, and the electric machine shaft rotate about the axis of rotation; cause, in response to a turbine decouple command, the electric machine to cease generating the electric power; cause, in response to the turbine decouple command, an unloading operation to be performed, wherein performing the unloading operation comprises, over an unloading period, increasing a motor torque output provided by the electric machine on the coupler to increase mechanical power transmission from the electric machine to the propulsor and decreasing the torque output provided by the power turbine on the coupler to decrease mechanical power transmission from the power turbine to the propulsor; and when the torque output provided by the power turbine on the coupler reaches a predetermined threshold, cause the power turbine to disconnect from the coupler.

Description

PRIORITY INFORMATION The present application claims priority to U.S. Provisional Patent Application No. 63/390,327 filed on Jul. 19, 2022, which is incorporated by reference herein in its entirety for all purposes. FIELD The present disclosure relates to hybrid-electric propulsion systems for aircraft. BACKGROUND Hybrid-electric propulsion systems are being developed to improve an efficiency of aircraft. Such propulsion systems can include a gas turbine engine, an electric machine, and a propulsor, such as a fan or propeller. The integration of an electric machine with a gas turbine engine may present certain operational challenges in balancing or shifting the power between the electric machine and the gas turbine engine, maximizing the efficiency of the entire propulsion system, and/or coupling/decoupling these components from one another for safety or other operational purposes. Accordingly, a system designed to address one or more of these challenges would be a welcome addition to the art. BRIEF DESCRIPTION OF THE DRAWINGS A full and enabling disclosure of the present disclosure, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: FIG. 1 is a schematic top view of an exemplary aircraft having a hybrid-electric propulsion system in accordance with an exemplary aspect of the present disclosure; FIG. 2 is a schematic cross-sectional view of a propulsion assembly of the aircraft of FIG. 1; FIG. 3 is a cross-sectional view of a coupler of the propulsion assembly of FIG. 2; FIG. 4 is a schematic view of the coupler of FIG. 3 and depicts a first mode of operation in which a propulsor shaft, a power turbine shaft, and an electric machine shaft are all mechanically coupled with the coupler; FIG. 5 is a schematic view of the coupler of FIG. 3 and depicts a second mode of operation in which the propulsor shaft and the power turbine shaft are mechanically coupled with the coupler while the electric machine shaft is mechanically decoupled from the coupler; FIG. 6 is a schematic view of the coupler of FIG. 3 and depicts a third mode of operation in which the propulsor shaft and the electric machine shaft are mechanically coupled with the coupler while the power turbine shaft is mechanically decoupled from the coupler; FIG. 7 is a schematic view of the coupler of FIG. 3 and depicts a fourth mode of operation in which the power turbine shaft is mechanically coupled with the coupler while the propulsor shaft and the electric machine shaft are mechanically decoupled from the coupler; FIG. 8 is a schematic view of the coupler of FIG. 3 and depicts a fifth mode of operation in which the power turbine shaft and the electric machine shaft are mechanically coupled with the coupler while the propulsor shaft is mechanically decoupled from the coupler; FIG. 9 is a schematic view of the coupler of FIG. 3 and depicts a sixth mode of operation in which the power turbine shaft, the propulsor shaft, and the electric machine shaft are mechanically decoupled from the coupler; FIG. 10 is a data flow diagram depicting an example manner in which the coupler of FIG. 3 can be controlled to couple/decouple various components to or from the coupler; FIG. 11 a flow diagram of a method of decoupling a turbine from a coupler in accordance with an exemplary aspect of the present disclosure; FIG. 12 is a graph corresponding to the method of decoupling the turbine from the coupler set forth in FIG. 11 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time; FIG. 13 a flow diagram of a method of coupling a turbine to a coupler in accordance with an exemplary aspect of the present disclosure; FIG. 14 is a graph corresponding to the method of coupling the turbine to the coupler set forth in FIG. 13 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time; FIG. 15 a flow diagram of a method of decoupling an electric machine from a coupler in accordance with an exemplary aspect of the present disclosure; FIG. 16 is a graph corresponding to the method of decoupling the electric machine from the coupler set forth in FIG. 15 and depicts a speed of the power turbine and a speed of the electric machine as functions of time and a torque output of the power turbine and a torque output of the electric machine as functions of time; FIG. 17 a flow diagram of a method of coupling an electric machine to a coupler in accordance with an exemplary aspect of the present disclosure; FIG. 18 is a graph corresponding to the method of coupling the electric machine to the coupler set forth in FIG. 17 and depicts a speed of the power turbine and a speed of the electric