Propulsion System Electric Fan Drive for Jet Responsiveness
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Solution Overview
Problem
Military jet engines have low bypass ratios due to performance and weight concerns, making them less efficient and less responsive, which is not suitable for fast jet aircraft that require rapid airspeed variations.
Innovation Solution
A propulsion system that includes an electric motor mechanically coupled to the fan to enhance its rotation speed, allowing for larger fans without reducing performance, using a controller to selectively operate the electric motor in drive or energy generation modes based on thrust demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a larger fan is used to increase efficiency and bypass ratio, then fuel efficiency improves, but engine responsiveness deteriorates
Solution Approach 1:
The patent applies dynamics by making the fan drive system adjustable and flexible. The fan can be driven by either the turbine alone or by both the turbine and electric motor, allowing the system to adapt its configuration based on operational requirements. This dynamic switching capability enables the system to optimize between efficiency and responsiveness as needed.
Solution Approach 2:
The electric motor serves as an intermediary device that bridges the gap between turbine-driven efficiency and direct responsiveness. By introducing this intermediate power source, the system can achieve rapid fan acceleration without being constrained by turbine response characteristics, thus resolving the contradiction between efficiency and responsiveness.
2Use of energy by moving object
If a larger fan is used to increase bypass ratio, then efficiency improves, but power-to-weight ratio deteriorates
Solution Approach 1:
The patent segments the fan drive system into two independent power sources: the turbine and the electric motor. This segmentation allows each component to contribute differently to the overall power output, enabling the system to maintain high efficiency through the turbine while the electric motor provides additional power bursts without adding proportional weight to the turbine system.
Solution Approach 2:
The electric motor is designed to serve multiple functions: it can drive the fan during acceleration, supplement turbine output during high-power demands, and potentially generate electricity during deceleration. This multi-functionality allows the system to achieve improved efficiency with a larger fan while maintaining power-to-weight ratio through a single versatile component rather than multiple dedicated systems.
3Speed
If fan rotation speed is increased to improve responsiveness, then thrust generation improves, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by using the electric motor intermittently rather than continuously. The motor is activated during specific periods when rapid fan acceleration or additional thrust is required, and remains inactive during periods where turbine-driven operation is sufficient. This periodic activation pattern allows the system to achieve improved responsiveness when needed while minimizing energy consumption from the electric motor.
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 achieves increased responsiveness and efficiency by allowing faster fan rotation and thrust generation, enabling more efficient engines with larger fans without compromising performance.
Implementation Method 1
a turbine arranged proximate to the exhaust for driving the at least one fan
Implementation Method 2
an electric motor mechanically coupled to the at least one fan to drive the at least one fan to rotate
Implementation Method 3
at least one fan arranged proximate to the inlet for drawing air into a combustion chamber
Data Source
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AI summary
The present invention provides a propulsion system (1000) for a vehicle. The propulsion system comprises: a jet engine (10) for generating thrust, having a first end and a second end, the jet engine comprising: an inlet (101) arranged at the first end and an exhaust (106) arranged at the second end; at least one fan arranged proximate to the inlet for drawing air into a combustion chamber (104); and a turbine (105) arranged proximate to the exhaust for driving the at least one fan. The propulsion system also comprises an electric motor (20) mechanically coupled to the at least one fan to drive the at least one fan (102) to rotate while the at least one fan is being simultaneously driven by the turbine; and a controller for controlling the electric motor. The present invention also provides an aircraft having at least one propulsion system, and a method of operating a propulsion system.