Hybrid Aircraft Propulsion Coupling for Speed-Dependent Power Split
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Solution Overview
Problem
Conventional propulsion systems for aircraft, whether fixed-wing or rotary-wing, face challenges in balancing power requirements with energy/fuel consumption, weight, and reliability, especially in emergency failure situations, and existing hybrid electrical propulsion systems are complex and costly with high certification efforts.
Innovation Solution
A hybrid electrical propulsion system for aircraft that includes mechanical and electrical machines, with a power transmission device and control system, allowing speed-dependent coupling and optimized working points through a control logic that manages the contribution of both propulsion types based on speed and torque conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional propulsion systems use over-dimensioned thermal engines to ensure emergency failure situations, then reliability is improved, but fuel consumption and weight increase
Solution Approach 1:
The patent implements dynamic working point optimization by continuously adjusting the operating parameters of the thermal engine based on flight conditions. The control system adapts the engine's operating point to maintain optimal efficiency across varying power demands, rather than operating at a fixed over-dimensioned state. This dynamic adjustment resolves the contradiction by enabling the engine to operate efficiently during normal flight while maintaining reliability capabilities when needed.
Solution Approach 2:
The system changes operational parameters by transitioning between different propulsion modes (thermal-only, hybrid, electrical-only) and adjusting the thermal engine's working points. By varying parameters such as power output, fuel flow, and operating temperature according to flight phase and power demands, the system achieves both fuel efficiency and reliability without requiring permanent over-dimensioning of the thermal engine.
2Use of energy by moving object
If hybrid electrical propulsion systems combine thermal engines with electric motors, then fuel consumption is reduced, but device complexity increases
Solution Approach 1:
The electrical machine serves multiple functions: it acts as a motor during takeoff and climb phases, as a generator during descent for energy recovery, and provides auxiliary power for onboard systems. The thermal engine similarly operates in different modes including direct drive and combined cycle configurations. This multi-functionality reduces the need for separate dedicated components for each function, thereby limiting the increase in overall system complexity while achieving fuel savings.
Solution Approach 2:
The patent merges the thermal propulsion system and electrical propulsion system into a unified hybrid architecture with shared components such as the propeller, transmission elements, and control systems. By combining these systems rather than operating them as separate independent units, the patent achieves fuel consumption reduction through coordinated operation while minimizing the complexity increase that would result from fully independent dual systems.
3Use of energy by moving object
If hybrid propulsion systems optimize working points dynamically, then fuel consumption decreases, but control loop complexity increases
Solution Approach 1:
The control system implements feedback mechanisms that continuously monitor flight parameters (power demand, altitude, speed, thermal engine state) and adjust the operating points of both thermal and electrical propulsion components accordingly. This feedback-driven dynamic optimization enables fuel consumption reduction by maintaining optimal working points across varying conditions, while the structured feedback architecture manages control complexity through systematic parameter adjustment rather than requiring overly complex control algorithms.
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
Enhances reliability and safety by optimizing power allocation between mechanical and electrical propulsion, reducing weight and fuel consumption, and minimizing maintenance costs, while ensuring robustness and redundancy in failure scenarios.
Implementation Method 1
at least one thermal engine
Implementation Method 2
at least one electrical machine, wherein the at least one electrical machine is operable in motor mode or generator mode
Implementation Method 3
at least one electrical machine, wherein the at least one electrical machine is operable in motor mode or generator mode
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
The invention relates to a hybrid electrical propulsion system (500), which comprises a mechanical load (510); a thermal engine (520); an electrical machine (530); a power transmission device (540) comprising a first coupling device (545) connected via a first connecting shaft (523) to the thermal engine and via a second connecting shaft (546) to a second coupling device (547); and a control system (560) comprising a control logic (550) to provide a setpoint command (559) to the electrical machine. The first coupling device (545) 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 (547) couples a third connecting shaft (533) with a drive shaft (543) 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.