Hybrid electric taxi system (HETS) or full electric taxi system (FETS)

Patent metadata

Field	Value
Publication number	US-11623757-B2
Application number	US-201916435212-A
Country	US
Kind code	B2
Filing date	Jun 7, 2019
Priority date	Jun 8, 2018
Publication date	Apr 11, 2023
Grant date	Apr 11, 2023

Abstract

For aircraft taxiing, an aircraft is equipped with an electric machine installed in a propulsor gearbox (PGB), in parallel to the gas turbine, working in motor mode during taxi, and in generator mode during flight phases (such as take-off, climb, cruise, descent, approach and landing). Typical current systems which use an electric machine in the PGB do not use the electric machine in motor mode for taxi operations (i.e., it is only an additional generator). An optimized power supply providing a combination of a thermal engine such as an Auxiliary Power Unit (APU) and an electric energy storage system such as a battery provides power to the PGB electric machine even when the gas turbine is off.

First claim

The invention claimed is:

1. An aircraft propulsion system for an aircraft of the type including a gas turbine engine having a single power turbine shaft, the system comprising:
a gearbox directly coupled to the gas turbine engine single power turbine shaft, and also coupled to a second shaft and a third shaft;
a propulsor directly coupled to the gas turbine engine single power turbine shaft through the third shaft of the gearbox, the propulsor being configured to use rotational energy the gas turbine engine single power turbine shaft provides to propel the aircraft during some phases of flight of the aircraft such as takeoff and being further configured to act as a wind turbine during descent and/or landing flight phases of the aircraft;
an electric machine mechanically operatively coupled to the second shaft of the gearbox, the electric machine and the gas turbine engine single power turbine shaft being coupled to parallel to the propulsor through the gearbox, the electric machine being configured to work in a motor mode to power the propulsor through the second and third shafts of the gearbox during taxiing and to work in a generator mode to convert to electricity, rotational energy the propulsor acting as a wind turbine produces during the descent and/or landing flight phases; and
a power supply operatively coupled to the electric machine, the power supply supplying stored electrical power to the electric machine operating in the motor mode during taxiing and receiving and storing electrical power from the electric machine operating in the generator mode during the descent and/or landing flight phases to thereby contain harvested kinetic energy from the propulsor incoming airflow during a descent phase and subsequently discharge the captured energy to reuse it in the motor mode for aircraft taxi.

2. The system of claim 1 wherein the power supply is configured to provide a combination of a thermal engine such as an Auxiliary Power Unit (APU) and an electric energy storage system such as a battery to provide power to the electric machine during taxi-out when the gas turbine engine is off.

3. The system of claim 1 wherein the electric machine is also configured to rotate the gas turbine engine to start it.

4. The system of claim 1 further including a controller that switches the electric machine between the motor mode and the generator mode.

5. The system of claim 1 further including a controller that selectively charges the power supply with power produced by the electric machine during the descent and/or landing phases.

6. The system of claim 1 wherein the gearbox selectively mechanically couples the electric machine to the propulsor when the electric machine is operating in the motor mode.

7. The system of claim 1 wherein the electric machine comprises an electric motor that has an efficiency of 85% or more when operating in the motor mode to power the propulsor to produce thrust for taxiing.

8. The system of claim 1 wherein the propulsor comprises a propeller, and the electric machine is operable to regenerate power obtained from the propeller acting as a wind turbine engine during descent and/or landing phases for storage and powering the electric machine operating as a motor during subsequent taxiing without turning on the gas turbine engine.

9. A method for taxiing of an aircraft of the type including a gas turbine engine having a single power turbine shaft that is directly coupled to a gearbox, the method comprising:
controlling the gas turbine engine to directly provide rotational energy through the single power turbine directly coupled shaft and a gearbox to a propulsor to propel the aircraft during some phases of flight of the aircraft such as takeoff;
mechanically coupled an electric machine to the propulsor through a second shaft of the gearbox so the electric machine and gas turbine engine are coupled in parallel to the propulsor;
opening the electric machine in a motor mode to provide rotational energy to the propulsor during taxing while also turning the gas turbine single power turbine shaft;
operating the electric machine in a generator mode to convert to electricity, rotational energy the propulsor acting as a wind turbine produces during descent and landing;
supplying stored electrical power from (a) a power supply that is operatively coupled to the electric machine, (b) to the electric machine operating in the motor mode during taxiing; and
receiving and storing electrical power from the electric machine operating in the generator mode during the descent and/or landing flight phases, thereby containing harvested kinetic energy from the propulsor incoming airflow during a descent phase and subsequently discharging the captured energy and reusing it to apply to the electric machine operating in the motor mode for taxing.

10. The method of claim 9 including configuring the power supply to provide a combination of a thermal engine such as an Auxiliary Power Unit (APU) and an electric energy storage system such as a battery to provide power to the electric machine during taxi-out when the gas turbine engine is off.

11. The method of claim 9 wherein the electric machine comprises a starter/generator and the method includes opertaing the starter/generator to rotate the gas turbine engine to start it.

12. The method of claim 9 further including using a controller to switch the electric machine between the motor mode and the generator mode.

13. The method of claim 9 further including using a controller to selectively charge the power supply with power produced by the electric machine during flight phases.

14. The method of claim 9 further including selectively connecting the electric machine to the propulsor via the gearbox when operating in the motor mode.

15. The method of claim 9 wherein the electric machine comprises an electric motor/generator having an efficiency of 85% or more when operating in the motor mode to power the propulsor to produce thrust for taxiing.

16. The method of claim 9 further including the electric machine regenerating power obtained from the propulsor comprising a propeller acting as a wind turbine during descent and/or landing phases and storing the regenerated power for powering the electric machine operating as an electric motor during subsequent taxiing without turning on the gas turbine engine.

Assignees

• Embraer Sa

Inventors

• Ribeiro Raphael Felipe Gama
• Neto Francisco Palazzo

Classifications

• B64D35/024

  of series type · CPC title

• B64D35/025

  of parallel type · CPC title

• B64D35/022

  of hybrid-electric type · CPC title

• B64D27/33

  Hybrid electric aircraft · CPC title

• F02C6/20 Primary

  Adaptations of gas-turbine plants for driving vehicles · CPC title