Hybrid Electric Engine Power Splitting for Fast Aircraft Thrust Response

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Solution Overview

Problem

Commercial aircraft using auto-throttle control experience fast low-amplitude transients and slow engine response due to turbomachinery and fuel system dynamics, impacting performance and passenger comfort.

Innovation Solution

Implementing a power splitting algorithm between hybrid electric motors connected to the low and high spools of an aircraft engine, utilizing a neural network to determine optimal power splits between fuel and electrical power, enhancing thrust response and maintaining constant fuel flow.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If aggressive fuel throttle command is used to maintain constant flight speed and altitude, then the auto-throttle control response is faster, but fast low-amplitude transients occur in the engine which impact performance and disable turbine active clearance control

Engineering Contradiction:
Improveauto-throttle control response speedVSAvoidengine performance stability
Core Design Contradiction:
SpeedVSReliability

Solution Approach 1:

The invention segments the power delivery system into two independent pathways: a conventional fuel throttle pathway for steady-state power control and a hybrid electric motor pathway for transient response. The hybrid electric motor is connected to the engine spool to provide direct mechanical assistance, while the fuel throttle maintains smooth, stable operation. This segmentation allows the aggressive response to be delivered through the electric motor without causing harmful transients in the fuel system.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The hybrid electric motor acts as an intermediary between the auto-throttle controller and the engine. Instead of directly commanding aggressive fuel flow changes, the controller commands the hybrid electric motor to provide the necessary torque assistance. This intermediary approach delivers the required thrust response while filtering out the harmful transients that would otherwise occur in the fuel system and turbine clearance control.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Speed

If conventional fuel system dynamics are used, then the engine structure is simple, but the engine response is slow due to turbomachinery and fuel system dynamics which impacts ride quality and passenger comfort

Engineering Contradiction:
Improveengine response speedVSAvoidpower system complexity
Core Design Contradiction:
SpeedVSDevice complexity

Solution Approach 1:

The invention merges a hybrid electric motor with the existing turbomachinery engine to create a combined power delivery system. The hybrid electric motor is mechanically coupled to the engine spool, combining its fast electrical response characteristics with the engine's existing structure. This merging provides rapid thrust response for improved ride quality while leveraging the established simplicity and reliability of conventional turbomachinery architecture.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP4620823A1Fast thrust response using optimal power splitting in hybrid electric aircraft
Publication Date: 2025.09.24 RTX CORP
  • EP4620823A1 patent drawingFigure 1
  • EP4620823A1 patent drawingFigure 2
  • EP4620823A1 patent drawingFigure 3

AI summary

A system including a engine (114) having a low spool (112) and a high spool (110), a first hybrid electric motor (106) connected to the low spool (112) and a second hybrid electric motor (108) connected to the high spool (110). An auto-throttle (102) controls an amount of power provided to the engine (114) responsive to at least one aircraft parameter. A power splitting algorithm (104) implemented between the auto-throttle (102) and at least one of the first and second hybrid electric motors (106, 108) determines a power split dividing the total engine power into the power produced by burning fuel and electrical power provided to the at least one of the first and second hybrid electric motors (106, 108) responsive to control signals from the auto-throttle (102).