Hybrid Aircraft Power Plant Architecture for Independent Dual-Mode Drive
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Solution Overview
Problem
Hybrid aircraft power plants face challenges in optimizing architecture for independent operation of thermal engines and electric motors, while minimizing production and maintenance costs, and achieving weight reduction and increased reliability.
Innovation Solution
The hybrid aircraft power plant incorporates an epicyclic gearing system with an overrunning clutch, allowing the thermal engine and electric motor to operate independently or together, with the overrunning clutch preventing rotation of the ring gear in one direction and allowing it in the other, coupled with a structure that secures the thermal engine and electric motor, optimizing power distribution and reducing complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an epicyclic gearing system with overrunning clutch is used to enable independent operation of thermal engine and electric motor, then operational versatility is improved, but device complexity increases
Solution Approach 1:
The epicyclic gearing system is designed to perform multiple functions: it enables the thermal engine to drive the output shaft directly, allows the electric motor to drive the output shaft independently, and permits both power sources to operate simultaneously. The overrunning clutch automatically engages or disengages based on operational mode, providing universal functionality without requiring separate transmission paths for each operation mode.
Solution Approach 2:
The patent employs a nested configuration where the electric motor is positioned within the epicyclic gearing structure, and the overrunning clutch is integrated into the ring gear assembly. This nesting allows compact arrangement of multiple components in concentric or overlapping spatial relationships, reducing overall system footprint while maintaining functional independence of each component.
2Ease of manufacture
If the number of parts is reduced to limit production and maintenance costs, then manufacturing cost is improved, but operational flexibility deteriorates
Solution Approach 1:
The shared epicyclic gearing structure serves as a universal mechanism that accommodates both thermal engine and electric motor operation modes. Instead of providing separate transmission systems for each power source, the single epicyclic gearset handles all power transmission needs, significantly reducing part count while preserving full operational flexibility for independent and combined operation.
Solution Approach 2:
The overrunning clutch acts as an intermediary element that automatically manages power flow between the two independent power sources and the common output shaft. This single intermediary component enables the system to switch between operational modes without requiring complex control mechanisms or additional parts, maintaining operational flexibility while minimizing component count.
3Device complexity
If active control systems are eliminated to simplify architecture, then device complexity is reduced, but control precision may deteriorate
Solution Approach 1:
The overrunning clutch is designed as a self-regulating passive component that automatically engages or disengages based on the relative rotational speeds and directions of the thermal engine and electric motor. The system self-manages power flow distribution without requiring external sensors, actuators, or control algorithms, achieving mode transition through inherent mechanical characteristics rather than active control.
Solution Approach 2:
The patent replaces active electronic control systems with a passive mechanical overrunning clutch mechanism. The clutch's inherent mechanical properties—allowing free rotation in one direction while preventing rotation in the opposite direction—provide automatic mode selection and power flow management, substituting complex electronic control with simple, reliable mechanical behavior.
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 configuration enables efficient operation in both thermal and electric modes, reducing weight and maintenance costs, and enhancing reliability by simplifying the power plant architecture and eliminating the need for active control systems.
Implementation Method 1
an overrunning clutch coupling the ring gear to the structure, the overrunning clutch allowing rotation of the ring gear in a first direction, and preventing rotation of the ring gear in a second direction
Implementation Method 2
an epicyclic gearing having a sun gear coaxial to a ring gear, a plurality of planet gears meshed between the sun gear and the ring gear, and a carrier coaxial to the sun gear and to the ring gear
Data Source
AI summary
The power plant can have a structure; an output shaft connectable to a load, the output shaft rotatable about an axis relative the structure; a thermal engine secured to the structure, the thermal engine having a thermal engine shaft; an electric motor having a stator and a rotor shaft, the stator secured to the structure; an epicyclic gearing having a sun gear coaxial to a ring gear, a plurality of planet gears meshed between the sun gear and the ring gear, and a carrier coaxial to the sun gear and to the ring gear, the sun gear, carrier, and ring gear being rotatable relative the casing structure, the output shaft and the rotor shaft both coupled to the carrier, and the thermal engine shaft coupled to sun gear and the carrier; and an overrunning clutch operable to prevent the rotation of the ring gear in one angular direction.