Hybrid Rotor Power Unit for Fast Thrust Control and Longer Flight
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Solution Overview
Problem
Current aircraft power unit systems face challenges in achieving rapid thrust control and maneuverability due to the slow torque response of internal-combustion engines and the limited power density of electric batteries, which affects the stability and payload capacity of multi-rotor aerial vehicles.
Innovation Solution
A hybrid power unit system combining a primary electric motor and an internal-combustion engine, with a local controller that adjusts throttle setpoints and torque output to achieve rapid rotor speed changes and maintain battery state of charge, utilizing a cooling fan for additional thrust augmentation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If an internal-combustion engine is used for thrust generation, then extended flight time and high energy density are achieved, but rapid torque response and maneuverability are compromised
Solution Approach 1:
The patent combines an internal-combustion engine and an electric motor into a hybrid power unit that drives a common rotor. The internal-combustion engine provides sustained power for extended flight time, while the electric motor delivers rapid torque for maneuverability. This merging allows both power sources to work together to resolve the contradiction between flight duration and response speed.
Solution Approach 2:
The control system dynamically adjusts the torque contribution from each power source based on flight conditions. During maneuvers requiring rapid response, the electric motor provides immediate torque while the internal-combustion engine ramps up. This dynamic allocation optimizes both flight time and maneuverability across different operating phases.
2Speed
If an electric motor is used for rapid torque changes, then maneuverability is improved, but power density and flight time are limited
Solution Approach 1:
The hybrid power unit merges the high power density and rapid response of an electric motor with the high energy density and sustained output of an internal-combustion engine. The electric motor handles transient torque demands for maneuverability, while the internal-combustion engine provides baseline power for extended flight duration, resolving the contradiction between response speed and flight time.
Solution Approach 2:
The electric motor is sized to provide partial power output rather than full thrust. It delivers excessive torque during maneuvers when needed, but operates at reduced capacity during steady-state flight, allowing the internal-combustion engine to carry the load for extended duration while maintaining the electric motor's ability to enhance maneuverability.
3Adaptability or versatility
If a hybrid power unit is implemented, then both rapid torque response and extended flight time are achieved, but system complexity increases
Solution Approach 1:
The patent merges two power sources into a single integrated power unit that shares common components such as the rotor, transmission, and control system. This merging approach achieves versatile thrust control capability while limiting complexity growth by consolidating shared subsystems rather than maintaining entirely separate power trains.
Solution Approach 2:
The control system is designed with multi-functionality to manage both power sources, the clutch mechanism, and thrust distribution. This universal control architecture handles diverse operations including engine starting, torque blending, and maneuver execution, reducing the need for separate dedicated systems and thereby limiting overall complexity despite the hybrid configuration.
4Duration of action of moving object
If the internal-combustion engine is used to drive the rotor, then sustained thrust is achieved, but rapid rotor speed changes are limited
Solution Approach 1:
The hybrid power unit combines the sustained thrust capability of the internal-combustion engine with the rapid power delivery of the electric motor. Both power sources drive the same rotor through a clutch mechanism, allowing the electric motor to supplement or augment engine power during rapid acceleration or maneuvering, thereby achieving both sustained thrust and rapid power delivery.
Solution Approach 2:
The clutch mechanism acts as an intermediary between the internal-combustion engine and the rotor. It enables smooth engagement and disengagement of the electric motor with the engine-driven rotor, allowing rapid power delivery from the electric motor without mechanical shock to the engine, thus achieving rapid rotor speed changes while maintaining sustained thrust capability.
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 enables extended flight times, increased payload capacity, and improved maneuverability by leveraging the high energy density of liquid fuels and rapid torque changes from the electric motor, while maintaining efficient engine operation and battery health.
Implementation Method 1
a cooling fan coupled to the engine shroud and configured to displace air through the engine shroud
Implementation Method 2
a primary electric motor including a motor output; a rotor coupled to the motor output
Implementation Method 3
an internal-combustion engine including an output shaft and a cylinder head
Implementation Method 4
a clutch interposed between the output shaft and the motor output and configured to selectively transfer torque
Data Source
AI summary
One variation of a system for generating thrust at an aerial vehicle includes: a primary electric motor; a rotor coupled to the motor; an internal-combustion engine; a clutch interposed between the motor and an output shaft of the internal-combustion engine; an engine shroud defining a shroud inlet between the rotor and the internal-combustion engine, extending over the internal-combustion engine, and defining a shroud outlet opposite the rotor; a cooling fan coupled and configured to displace air through the engine shroud; and a local controller configured to receive a rotor speed command specifying a target rotor speed, adjust a throttle setpoint of the internal-combustion engine according to the target rotor speed and a state of charge of a battery in the aerial vehicle, and drive the primary electric motor to selectively output torque to the rotor and to regeneratively brake the rotor according to the target rotor speed.