Aircraft Hybrid Propulsion Descent Control for Noise Reduction
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Solution Overview
Problem
Current hybrid propulsion systems for aircraft face challenges in reducing noise and emissions during descent, particularly due to the operation of internal combustion engines at low power levels, which can lead to increased harmful emissions and noise pollution.
Innovation Solution
A control system for a hybrid propulsion system that operates a gas turbine engine at a higher power level during descent, with the generated electric power being stored in an energy storage device, allowing for reduced engine noise and emissions by increasing engine thermal efficiency and closing handling bleeds, while maintaining thrust levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the gas turbine engine is operated at a lower power level during descent, then fuel consumption is reduced, but harmful emissions and noise level increase
Solution Approach 1:
The system changes the operating parameters of the gas turbine engine by operating it at a higher power level during descent rather than a lower power level. This parameter change increases thermal efficiency and closes handling bleeds, thereby reducing harmful emissions and noise while the generator captures excess energy to offset the increased fuel consumption
Solution Approach 2:
The system converts the normally harmful effect of operating at high power during descent into a beneficial effect by using the generator to capture excess energy. The high power operation, which would normally increase fuel consumption, is transformed into an opportunity to store energy in the electrical energy storage device, thereby reducing overall fuel consumption while maintaining low emissions and noise
2Object-generated harmful factors
If the generator is operated at a higher power level during descent, then engine thermal efficiency increases and emissions reduce, but energy storage capacity requirements increase
Solution Approach 1:
The system applies partial action by operating the generator at a moderate higher power level rather than maximum capacity. This allows sufficient energy capture to offset the increased fuel consumption during high power engine operation, while avoiding the need for excessively large energy storage capacity. The generator operates at optimized power levels that balance emissions reduction with storage requirements
3Object-generated harmful factors
If handling bleeds are closed to increase engine thermal efficiency, then emissions reduce, but engine response time may be affected
Solution Approach 1:
The control system performs preliminary action by pre-positioning the handling bleeds in a closed state during descent operation. This preliminary positioning allows the engine to operate at optimal thermal efficiency points without delay, as the bleeds are already in the correct state to maximize efficiency while maintaining acceptable response characteristics through advance system preparation
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 approach reduces noise and emissions during descent by operating the engine at a higher power level, increasing thermal efficiency, and utilizing stored energy for later phases of flight, thereby enhancing engine performance and reducing fuel consumption.
Implementation Method 1
a gas turbine engine coupled to an electric generator... electric power generated by the electric generator during operation in the second descent mode is stored in the electrical energy storage device
Implementation Method 2
a propulsor coupled to an electric motor
Data Source
AI summary
A control system for an aircraft hybrid propulsion system comprising a gas turbine engine coupled to an electric generator, a propulsor coupled to an electric motor, and an electrical storage device coupled to the motor and the generator. The control system configured to operate the propulsion system in a first descent mode and a second descent mode. In the first descent mode, the gas turbine engine is operated at a first engine power level and the generator is operated at a first generator power level. In the second descent mode, the gas turbine engine is operated at a second engine power level, higher than the first engine power level, and the generator is operated at a second generator power level, higher than the first generator power level. Electric power generated by the electric generator during operation in the second descent mode is stored in the electrical storage device.