Hybrid Electric Torque Balancing for Takeoff and Cruise Efficiency

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Solution Overview

Problem

Conventional aircraft engines are oversized for cruising, leading to inefficiencies in power usage and potential weight and size issues that impact performance and fuel efficiency.

Innovation Solution

A hybrid electric engine control module (ECU) that manages torque output between a heat engine system and an electric motor system, allowing for adaptive power splitting based on real-time parameters such as battery state and sensor data.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If conventional aircraft engines are sized to provide maximum thrust for takeoff, then takeoff performance is improved, but engine efficiency during cruising deteriorates due to oversized capacity

Engineering Contradiction:
Improvetakeoff thrustVSAvoidengine efficiency during cruise
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The patent divides the power delivery function into two separate systems: a heat engine system for baseline power and an electric motor system for supplemental power during high-demand phases. This segmentation allows each system to operate in its optimal efficiency range - the heat engine at steady-state cruising efficiency and the electric motor during transient takeoff phases, resolving the contradiction between takeoff thrust and cruise efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent implements dynamic power splitting where the proportion of power from the heat engine versus electric motor changes continuously based on flight conditions. During takeoff, the electric motor provides a higher proportion of power; during cruise, the heat engine operates at optimal efficiency. This dynamic adjustment resolves the contradiction by adapting the power mix to match instantaneous performance requirements.

Inventive Principle:
Principle #15Dynamics

2Power

If engine size is increased to meet peak power demands, then maximum power capability is improved, but aircraft weight increases

Engineering Contradiction:
Improvemaximum power capabilityVSAvoidaircraft weight
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The patent segments the power generation into two lighter components (heat engine and electric motor) rather than requiring one oversized heat engine. The electric motor system can be sized to provide only the supplemental power needed during peak demand, reducing the size and weight of the primary heat engine while maintaining maximum power capability through combined output.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent changes the operational parameters of the heat engine by allowing it to operate continuously at or near its optimal efficiency point rather than being oversized to handle peak loads. The electric motor system compensates for the reduced heat engine size during high-power phases, enabling weight reduction while maintaining maximum power capability.

Inventive Principle:
Principle #35Parameter changes

3Power

If engine size is increased to provide excess power for takeoff, then takeoff performance is improved, but device complexity increases

Engineering Contradiction:
Improvetakeoff powerVSAvoidpowerplant system complexity
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent makes the electric motor system multi-functional: it provides supplemental power during takeoff, enables the heat engine to operate at optimal efficiency during cruise, and can serve as a starter motor. This universality allows the system to achieve improved takeoff performance without proportionally increasing complexity, as the electric motor performs multiple roles rather than requiring dedicated systems for each function.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent introduces a control system as an intermediary that manages power distribution between the heat engine and electric motor based on flight conditions. This intermediary control system automates the complex coordination required, reducing the operational burden on pilots and managing the complexity of coordinating multiple power sources while achieving improved takeoff performance.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP3931096B1Torque balancing for hybrid electric propulsion systems and aircraft utilizing hybrid electric propulsion systems
Publication Date: 2025.01.29 PRATT & WHITNEY CANADA CORP
  • EP3931096B1 patent drawingFigure 1
  • EP3931096B1 patent drawingFigure 2
  • EP3931096B1 patent drawingFigure 3A

AI summary

A hybrid electric engine control module (ECU) configured to be operatively connected to a hybrid electric aircraft powerplant having a heat engine system and an electric motor system to control a torque output from each of the heat engine system and the electric motor system. The ECU can be configured to receive a torque command and split output power between the electric motor system and the heat engine system. Additionally and/or alternatively, the ECU can be configured to balance a total torque against a second total torque of a second aircraft powerplant.