Hybrid Aircraft Propulsion Speed Control After Main Regulation Failure

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Solution Overview

Problem

Existing parallel hybrid propulsion systems for aircraft face challenges in regulating propulsion device rotational speed when the main regulation system of the heat engine fails, particularly in cases of total regulation failure, leading to the need for emergency maneuvers without the full power output of the main engine.

Innovation Solution

A method and device for controlling the rotational speed of a propulsion device using a backup regulation system for the heat engine and an electric motor, where the backup system adjusts fuel flow to modulate power output based on the electric motor's instantaneous power, ensuring continued regulation even in the event of main regulation system failure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the main regulation system of the heat engine fails, then the engine continues to run and output power, but the power output cannot be regulated

Engineering Contradiction:

Improveengine operation continuityVSAvoidpower regulation capability

Core Design Contradiction:

ReliabilityVSEase of operation

Solution Approach 1:

The patent introduces a backup regulation system as an intermediary component that takes over power regulation functions when the main regulation system fails. This backup system uses alternative sensors and control mechanisms to regulate the fuel injection quantity, thereby maintaining power regulation capability despite main system failure.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent changes the operational parameters of the fuel injection system by switching from the main regulation system's control mode to the backup regulation system's control mode. This involves changing the control signal source and the fuel injection quantity parameters to maintain regulated operation under failure conditions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If only the auxiliary electric motor is used after main engine failure, then the aircraft can perform emergency maneuvers, but the flight duration is limited and battery power is consumed rapidly

Engineering Contradiction:

Improveemergency maneuver capabilityVSAvoidflight duration

Core Design Contradiction:

ReliabilityVSDuration of action of moving object

Solution Approach 1:

The patent prepares the backup regulation system in advance during normal operation, ensuring it is ready to take over immediately upon main system failure. This preliminary preparation includes maintaining standby control mechanisms and fuel management systems that can be activated without delay, enabling seamless transition and extended operational duration.

Inventive Principle:

Principle #10Preliminary action

3Reliability

If the main regulation system is completely locked, then the engine runs at fixed power output, but the propulsion device rotational speed cannot be maintained within acceptable range

Engineering Contradiction:

Improveengine operation stabilityVSAvoidpropulsion device rotational speed control

Core Design Contradiction:

ReliabilityVSSpeed

Solution Approach 1:

The patent implements a feedback mechanism in the backup regulation system that continuously monitors the propulsion device rotational speed and adjusts the fuel injection quantity accordingly. This closed-loop control uses speed feedback to maintain the rotational speed within the acceptable range, compensating for the main system's complete lock.

Inventive Principle:

Principle #23Feedback

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

Enables continued modulation of power output by both motors, maintaining propulsion device stability and safety during emergency conditions, extending flight duration and minimizing battery power consumption.

Implementation Method 1

the heat engine being provided with a fuel circuit capable of supplying fuel into a combustion chamber of the heat engine

Methodology Applied

Scientific EffectCombustion: Combustion

Implementation Method 2

an electric secondary motor (so-called motor 2), connected to the MGB and arranged so as to output mechanical power PM2 to the MGB

Methodology Applied

Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Data Source

PatentUS12460587B2Method for regulating the speed of rotation of a propulsion device of a hybrid propulsion unit for an aircraft, in the event of a failure of the main regulation system of the heat engine of the hybrid propulsion unit

Publication Date: 2025.11.04 SAFRAN HELICOPTER ENGINES

AI summary

A method for regulating the speed of a propulsion device of an aircraft including: the propulsion device and a gearbox MGB; the heat engine and at least one electric motor, mounted in parallel on the MGB, the heat engine having a fuel circuit; main and backup regulation systems, and a regulation system, each capable of regulating the speed of the heat engine or the electric motor, respectively; a control system of the aircraft, capable of sending a speed or power setpoint to each of the regulation of the heat engine and the electric motor. The method includes: sending a speed setpoint NM2ref to the regulation system of the electric motor, the regulation system sending a power command PM2*, to obtain an instantaneous power PM2m; simultaneously, sending a speed or power command to the backup regulation system of the heat engine, the backup regulation system sending a selected fuel flow command QCarbAux* to the fuel circuit of the heat engine.