Hybrid Aircraft Propulsion Charging via Engine Load Control

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Solution Overview

Problem

Existing hybrid aircraft propulsion systems face challenges in achieving dynamic fuel efficiency and in-flight recharging of energy storage systems, particularly due to oversized engines and lengthy ground-based charging times.

Innovation Solution

A parallel hybrid propulsion system that utilizes the excess capacity of the thermal combustion engine to generate additional in-flight electric power, optimizing fuel efficiency by adjusting the load on the thermal combustion engine and using the generated power to recharge energy storage systems.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the thermal combustion engine is oversized for peak power requirements during takeoff and climb, then the engine can provide sufficient power for all flight phases, but the engine operates at below peak fuel efficiency during cruise and descent phases

Engineering Contradiction:
Improveengine power outputVSAvoidfuel efficiency
Core Design Contradiction:
PowerVSUse of energy by moving object

Solution Approach 1:

The propulsion system is segmented into two independent power sources: a thermal combustion engine and an electric motor with energy storage system. This allows each component to be sized optimally for its specific function - the thermal engine for cruise efficiency and the electric system for takeoff/climb power bursts - eliminating the need for an oversized engine that operates inefficiently during light-load phases.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The patent combines thermal and electric propulsion systems in a parallel hybrid architecture where both power sources can operate simultaneously or independently. The mechanical outputs are combined to drive the propulsor, allowing the thermal engine to operate at optimal efficiency points while the electric motor supplements power during high-demand phases.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of manufacture

If the battery is recharged through a ground based charger after landing, then the hybrid system can be reset for the next flight, but the charging time is much longer and may take several hours to fully recharge

Engineering Contradiction:
Improvecharging infrastructureVSAvoidcharging time
Core Design Contradiction:
Ease of manufactureVSLoss of time

Solution Approach 1:

The system performs recharging actions during the flight itself by utilizing excess thermal engine power to generate electricity and charge the battery while airborne. This preliminary charging action during cruise phases reduces or eliminates the need for lengthy ground-based charging, enabling faster turnaround times between flights.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The battery charging process continues uninterrupted during cruise phases of flight rather than being confined to ground operations. The thermal engine continuously generates excess power that is converted to electricity and stored in the battery, maintaining continuous useful action throughout the flight duration.

Inventive Principle:
Principle #20Continuity of useful action

3Use of energy by moving object

If parallel hybrid propulsion architectures are used for short flights in the region of 185-370 km, then fuel efficiency can be improved during cruise, but the charging time needed to fully recharge the batteries does not allow sufficient turnaround time

Engineering Contradiction:
Improvefuel efficiencyVSAvoidturnaround time
Core Design Contradiction:
Use of energy by moving objectVSProductivity

Solution Approach 1:

The system dynamically adjusts the power distribution between thermal engine and electric motor based on real-time flight conditions. During cruise phases, the thermal engine operates at optimal efficiency points and simultaneously charges the battery. This dynamic operation allows the system to maintain fuel efficiency while reducing ground charging time, improving overall productivity and turnaround capability.

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This system enhances fuel efficiency by operating the thermal combustion engine at peak efficiency, reduces ground-based charging times, and provides additional power reserves for emergency situations.

Implementation Method 1

the electric motor may be used as a generator to charge the battery

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3895993B1Charging scheme for electric propulsion systems
Publication Date: 2025.01.29 HAMILTON SUNDSTRAND CORP
  • EP3895993B1 patent drawingFigure 1~2
  • EP3895993B1 patent drawingFigure 3~4
  • EP3895993B1 patent drawingFigure 5~6

AI summary

An engine system (30) for an aircraft (1) comprising a propulsor (10) configured to drive the aircraft (1), a thermal combustion engine (14) configured to drive the propulsor (10), an electric motor (16) connected to the thermal combustion engine (14) and configured to drive the propulsor (10), a power converter (18) configured to apply a torque to the electric motor (16) and generate electric energy from the torque applied to the electric motor (16), and an engine controller (24), the engine controller (24) being configured to determine a current power output (P) of the thermal combustion engine (14), determine an optimum power output (P2) of the thermal combustion engine (14) based on current operating conditions, and vary the torque applied to the electric motor (16) so as to vary a load on the thermal combustion engine (14), wherein the torque may be varied by an amount required to vary the power output of the thermal combustion engine (14) to the determined optimum power output (P2).