Propulsion system for an aircraft

Patent metadata

Field	Value
Publication number	US-10676199-B2
Application number	US-201715619673-A
Country	US
Kind code	B2
Filing date	Jun 12, 2017
Priority date	Jun 12, 2017
Publication date	Jun 9, 2020
Grant date	Jun 9, 2020

Abstract

A hybrid-electric propulsion system for an aircraft includes a propulsor and a turbomachine. The turbomachine includes a high pressure turbine drivingly coupled to a high pressure compressor through a high pressure spool. The hybrid electric propulsion system further includes an electrical system including a first electric machine, a second electric machine, and an electric energy storage unit electrically connectable to the first and second electric machines. The first electric machine is coupled to the high pressure spool of the turbomachine and the second electric machine is coupled to the propulsor for driving the propulsor to provide a propulsive benefit for the aircraft. The hybrid electric propulsion system also includes a controller configured to provide electrical power from an electric power source to the first electric machine to drive the first electric machine to start, or assist with starting, the turbomachine.

First claim

What is claimed is:

1. A hybrid-electric propulsion system for an aircraft comprising:
a propulsor;
a turbomachine comprising a high pressure turbine drivingly coupled to a high pressure compressor through a high pressure spool;
an electrical system comprising a first electric machine, a second electric machine, and an electric energy storage unit electrically connectable to the first and second electric machines, the first electric machine coupled to the high pressure spool of the turbomachine and the second electric machine coupled to the propulsor for driving the propulsor to provide a propulsive benefit for the aircraft; and
a controller configured to provide electrical power from an electric power source to the first electric machine to drive the first electric machine to start, or assist with starting, the turbomachine when an acceleration of the high pressure spool falls below zero.

2. The hybrid-electric propulsion system of claim 1 , wherein the turbomachine is configured as part of a first turbofan engine, and wherein the propulsor is configured as part of a second turbofan engine.

3. The hybrid-electric propulsion system of claim 1 , wherein the turbomachine is configured as part of a turbofan engine, and wherein the propulsor is configured as part of an electric propulsor assembly.

4. The hybrid-electric propulsion system of claim 1 , wherein the high pressure turbine and the high pressure compressor at least partially define a core air flowpath, and wherein the first electric machine is positioned inward of the core air flowpath.

5. The hybrid-electric propulsion system of claim 1 , wherein the electric power source is the electric energy storage unit, wherein the electric energy storage unit is selectively in electrical communication with both the first electric machine and the second electric machine.

6. The hybrid-electric propulsion system of claim 1 , wherein the controller is further configured to extract electrical power from the first electric machine during operation of the turbomachine, wherein the electric energy storage unit is configured to store at least about fifty kilowatt-hours of electrical power, and wherein the first electric machine is configured to generate at least about fifty kilowatts during operation of the turbomachine.

7. The hybrid-electric propulsion system of claim 1 , wherein the electric energy storage unit is configured to store at least about sixty-five kilowatt-hours of electrical power.

8. A method for starting a turbomachine of a hybrid-electric propulsion system of an aircraft, the hybrid-electric propulsion system comprising a propulsor, a turbomachine, and an electrical system, the electrical system comprising a first electric machine coupled to a high pressure system of the turbomachine, a second electric machine coupled to the propulsor, and an electric energy storage unit, the method comprising:
receiving, by one or more computing devices, an engine start command;
providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine to drive the first electric machine and rotate a high pressure system of the turbomachine to at least a minimum threshold speed, wherein the minimum threshold speed is within about fifty-five percent of an idle speed of the turbomachine;
initiating, by the one or more computing devices, an igniting of a combustor of a combustion section of the turbomachine once the high pressure system of the turbomachine is rotating at least at the minimum threshold speed; and
providing, by the one or more computing devices, electrical power from the electric energy storage unit to the second electric machine to drive the propulsor and provide a propulsive benefit for the aircraft.

9. The method of claim 8 , wherein the engine start command is an engine restart command.

10. The method of claim 9 , wherein providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine comprises providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine such that the first electric machine rotates the high pressure system of the turbomachine solely in combination with an ambient airflow through the turbomachine.

11. The method of claim 8 , wherein the electric energy storage unit is configured to store at least about fifty kilowatt hours of electrical power.

12. A method for starting a turbomachine of a hybrid-electric propulsion system of an aircraft, the hybrid-electric propulsion system comprising a propulsor, a turbomachine, and an electrical system, the electrical system comprising a first electric machine coupled to a high pressure system of the turbomachine, a second electric machine coupled to the propulsor, and an electric energy storage unit, the method comprising:
receiving, by one or more computing devices, an engine start command;
receiving, by the one or more computing devices, data indicative of an engine start parameter value, wherein the engine start parameter value is at least one of an exhaust gas temperature value or a stall margin value;
providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine to drive the first electric machine and rotate the high pressure system of the turbomachine in response to the received data indicative of the engine start parameter value; and
initiating, by the one or more computing devices, an igniting of a combustor of a combustion section of the turbomachine.

13. The method of claim 12 , wherein providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine comprises modifying, by the one or more computing devices, an amount of electrical power provided from the electric energy storage unit to the first electric machine to drive the first electric machine and rotate the high pressure system of the turbomachine in response to the received data indicative of the engine start parameter value.

14. The method of claim 12 , wherein receiving, by the one or more computing devices, data indicative of the engine start parameter value comprises determining, by the one or more computing devices, further includes determining a core speed acceleration value is below a desired core speed acceleration threshold for startup, and wherein providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine comprises providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine in response to determining the core speed acceleration value is below the core speed acceleration threshold for startup.

15. The method of claim 12 , wherein receiving, by the one or more computing devices, data indicative of the engine start parameter value comprises determining, by the one or more computing devices, the exhaust gas temperature value is above a exhaust gas temperature threshold for startup, and wherein providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine comprises providing, by the one or more computing devices, electrical power from the electric energy storage unit to the first electric machine in response to determining the exhaust gas temperature value is above the core speed acceleration threshold for startup.

16. The method of claim 12 , wherein receiving, by t

Assignees

• Gen Electric

Inventors

• Hon Robert Charles
• Gansler Michael Thomas

Classifications

• B64D27/24 Primary

  using steam or spring force (jet aircraft B64D27/16) · CPC title

• B64D27/02 Primary

  Aircraft characterised by the type or position of power plants · CPC title

• F02C7/36

  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 title

• B64D31/06

  actuated automatically · CPC title

• B64D31/02

  Initiating means · CPC title