Hybrid Aircraft Power Plant With Selective Shaft Torque Coupling
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Solution Overview
Problem
Existing hybrid electric aircraft propulsion systems face challenges in efficiently integrating gas turbine engines with electric motors, particularly in managing torque transmission and rotational speed synchronization for optimal performance and starting capabilities.
Innovation Solution
A hybrid aircraft power plant design incorporating a gas turbine engine with a high-pressure and low-pressure spool, an electric motor, and a torque-transmitting device such as a clutch or continuously variable transmission (CVT) that allows selective engagement and disengagement between the electric motor and the high-pressure and low-pressure shafts, enabling flexible power distribution and synchronization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a hybrid electric aircraft propulsion system combines gas turbine engines with electric motors, then environmental benefits and cost savings are achieved, but challenges arise in managing torque transmission and rotational speed synchronization
Solution Approach 1:
A torque-transmitting device (clutch or CVT) is introduced as an intermediary component between the electric motor and the gas turbine engine shafts. This mediator enables flexible torque transmission while allowing independent control of rotational speeds, thereby managing the complexity of torque transmission and synchronization without compromising the environmental benefits of hybrid propulsion
Solution Approach 2:
The system employs dynamic engagement and disengagement capabilities of the torque-transmitting device, allowing real-time adjustment of power distribution between electric motor and gas turbine. This dynamic control enables optimal synchronization of rotational speeds and torque transmission, resolving the complexity management challenge while maintaining environmental advantages
2Adaptability or versatility
If a torque-transmitting device is used to selectively engage and disengage the electric motor from the high-pressure and low-pressure shafts, then flexible power distribution is enabled, but the device complexity increases
Solution Approach 1:
The torque-transmitting device is designed to perform multiple functions: selective engagement with high-pressure shaft, selective engagement with low-pressure shaft, and independent control of each shaft. This multi-functionality achieves flexible power distribution while consolidating control mechanisms, thereby managing the added complexity through unified design
Solution Approach 2:
The transmission system is segmented into independent control paths for high-pressure and low-pressure shafts, each with its own engagement mechanism. This segmentation allows flexible power distribution to different shafts while maintaining manageable complexity through modular, independent control of each path
3Speed
If the electric motor is drivingly engaged to the high-pressure shaft during starting, then rotational speed synchronization is improved, but torque transmission control becomes more difficult
Solution Approach 1:
The torque-transmitting device serves as a mediator that enables rotational speed synchronization during starting while providing independent torque transmission control. It allows the electric motor to drive the high-pressure shaft at synchronized speeds while maintaining the ability to control torque delivery, thereby resolving the contradiction between synchronization and control ease
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 the efficiency and flexibility of power distribution between the gas turbine engine and electric motor, facilitating smoother engine starting and operation, reducing environmental impact and operational costs.
Implementation Method 1
the clutch is a sprag clutch, the sprag clutch transmitting a torque from the electric motor to the high-pressure shaft when the electric motor rotates at a higher rotational speed than that of the high-pressure shaft
Data Source
Figure 1~2
Figure 3
Figure 4
AI summary
A hybrid aircraft power plant has a gas turbine engine (10) has a high-pressure spool (25) including a high-pressure compressor (25a), a high-pressure turbine (25b), and a high-pressure shaft (25c) drivingly engaging the high-pressure turbine (25b) to the high-pressure compressor (25a), a low-pressure spool (24) including a low-pressure compressor (24a), a low-pressure turbine (24b), and a low-pressure shaft (24c) drivingly engaging the low-pressure turbine (24b) to the low-pressure compressor (24a), an electric motor (32) drivingly engaged to the low-pressure shaft (24c), and a torque-transmitting device operatively connected to the high-pressure shaft (25c) and having an engaged configuration in which the torque-transmitting device drivingly engages the electric motor (32) to the high-pressure shaft (25c) and a disengaged configuration in which the torque-transmitting device disconnects the electric motor (32) from the high-pressure shaft (25c).