Hybrid Electric Propulsion Coupling for Engine-Failure Redundancy
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Solution Overview
Problem
Conventional propulsion systems in aircraft, whether fixed-wing or rotary-wing, face challenges in meeting power and energy efficiency requirements while ensuring safety and reliability, particularly in the event of engine failure, leading to over-dimensioned energy stores and non-ideal operational points.
Innovation Solution
A hybrid electrical propulsion system combining mechanical and electrical propulsion units with a power transmission device and control system that enables speed-dependent coupling, allowing optimized working points and redundancy for enhanced reliability and safety, using a control logic to manage power allocation between thermal engines and electric motors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional propulsion systems use overpowered jet engines to ensure operational continuity during engine failure, then safety and reliability are improved, but weight and energy consumption increase due to over-dimensioned energy stores
Solution Approach 1:
The propulsion system is segmented into multiple independent propulsion units (jet engines and electric motors), where each unit can independently provide thrust. This segmentation allows the aircraft to maintain operational capability with reduced energy store requirements, as the electric motors can compensate for jet engine failure without requiring excessive fuel reserves.
Solution Approach 2:
Electric motors are introduced as intermediary propulsion units that can bridge the gap during engine failure scenarios. These motors act as mediators between the primary jet engines and the aircraft's energy stores, providing supplemental thrust that reduces the need for over-dimensioned fuel reserves while maintaining safety.
2Reliability
If thermal engines are over-dimensioned to ensure emergency failure situations, then safety is improved, but fuel consumption increases during normal flight operations
Solution Approach 1:
The propulsion system dynamically adjusts the contribution of thermal engines and electric motors based on operational requirements. During normal flight, the system operates at optimal points with reduced thermal engine load, while during emergency situations, the electric motors dynamically compensate to maintain safety margins without requiring permanent over-dimensioning of the thermal engines.
Solution Approach 2:
The system changes operational parameters by switching between different propulsion configurations (thermal engine only, thermal engine with electric motor support, electric motor only). This allows the thermal engines to operate at efficient points during normal flight while still providing emergency capability through parameter changes in the overall propulsion mix.
3Use of energy by moving object
If hybrid propulsion systems combine thermal engines and electric motors, then power and energy efficiency are improved, but device complexity increases
Solution Approach 1:
The electric motors serve multiple functions: they provide supplemental thrust during takeoff and climb, compensate for jet engine failure, and can operate independently for certain flight phases. This multi-functionality justifies the added complexity by providing energy efficiency improvements across multiple operational scenarios without requiring separate systems for each function.
4Use of energy by moving object
If hybrid propulsion systems implement speed-dependent coupling with control logic, then working point optimization is improved, but control system complexity increases
Solution Approach 1:
The control logic implements feedback mechanisms that continuously monitor the operational state of the propulsion system and adjust the coupling between thermal engines and electric motors accordingly. This feedback-based control optimizes working points by automatically adjusting power distribution based on real-time conditions, achieving energy efficiency improvements that justify the control system complexity through automated optimization rather than manual intervention.
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
The system optimizes power and energy management, reduces wear and tear, minimizes fuel consumption, and enhances safety by sharing power between mechanical and electrical propulsion paths, improving overall aircraft reliability and reducing maintenance costs.
Implementation Method 1
at least one thermal engine (520) configured to drive a first connecting shaft (523) with a first rotational speed (N_TO) in a first rotational direction (524)
Implementation Method 2
at least one electrical machine (530), which is operable in motor mode or generator mode
Data Source
AI summary
A hybrid electrical propulsion system, which comprises a mechanical load; a thermal engine; an electrical machine; a power transmission device comprising a first coupling device connected via a first connecting shaft to the thermal engine and via a second connecting shaft to a second coupling device; and a control system comprising a control logic to provide a setpoint command to the electrical machine. The first coupling device couples the first connecting shaft with the second connecting shaft in a driving manner if a first speed-dependent driving condition is fulfilled. The second coupling device couples a third connecting shaft with a drive shaft in a driving manner if the control logic provides the setpoint command for operating the electrical machine in motor mode and a second speed-dependent driving condition is fulfilled.