Linear Motor Propeller Transmission for Precise Aircraft Speed Ratio
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Solution Overview
Problem
Current aircraft propulsion systems using rotary engines and propellers lack precision in speed ratio, which is desirable for improved performance.
Innovation Solution
A propulsion system incorporating linear electric motors with a unique transmission system, including a main gear, secondary gears, and connecting rods, along with a fuel cell-powered electric generator and a cooling system using dihydrogen for efficient energy and heat management, allowing for precise speed control and efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a rotary engine and propeller system is used, then the aircraft can achieve propulsion, but the speed ratio precision is insufficient
Solution Approach 1:
The patent replaces the traditional rotary engine with a linear electric motor, substituting a mechanical rotary system with an electric linear system. This substitution enables more precise control of the speed ratio between the propeller and the driving mechanism, directly addressing the speed ratio precision issue while maintaining propulsion functionality.
Solution Approach 2:
The transmission system is segmented into distinct functional components: the linear electric motor generates linear motion, the first converting mechanism (connecting rod and crank) converts linear motion to rotary motion, and the second converting mechanism (bevel gears) converts the rotary motion direction. This segmentation allows each component to be optimized for its specific function, improving overall speed ratio precision.
2Measurement precision
If linear electric motors are used with a transmission system, then speed ratio precision is improved, but the device complexity increases
Solution Approach 1:
The linear electric motor serves multiple functions: it generates linear motion directly, acts as the primary driving mechanism, and integrates the functions previously separated between engine and transmission components. This multi-functionality reduces the need for additional complex transmission elements while maintaining speed ratio precision.
Solution Approach 2:
The transmission system incorporates dynamic converting mechanisms that can adapt their motion conversion ratios. The first converting mechanism uses a connecting rod with adjustable articulation points, and the second uses selectable bevel gear combinations, allowing the system to dynamically adjust speed ratios for different operating conditions without requiring a completely different mechanical structure.
3Use of energy by moving object
If a fuel cell and cooling system are added, then energy efficiency is improved, but the system complexity increases
Solution Approach 1:
The fuel cell system is integrated to serve the dual purpose of generating electrical energy for the linear electric motor and providing cooling through its thermal management system. The waste heat from the fuel cell is utilized to cool the linear electric motor, creating a self-service arrangement where one subsystem supports another, thereby improving energy efficiency while minimizing the addition of separate cooling infrastructure.
Solution Approach 2:
The patent merges the fuel cell's electrical power generation function with its thermal management function into a unified system that simultaneously powers the linear electric motor and provides cooling. This combining of functions reduces the overall system complexity compared to having separate power and cooling systems, while improving overall energy efficiency.
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 a precise speed ratio and efficient energy use, with the cooling system effectively managing heat to maintain optimal performance of the linear electric motors, enhancing the aircraft's propulsion efficiency.
Implementation Method 1
at least one linear electric motor electrically powered by the electric generator and comprising a fixed element fixed to the chassis and a slide movable in translation along the fixed element
Implementation Method 2
a cooling system arranged to cool each linear electric motor... a delivery pipe which is arranged to ensure a heat exchange between the linear electric motor and the hydrogen circulating in the delivery pipe
Implementation Method 3
the electric generator is a fuel cell
Data Source
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AI summary
The invention relates to a propulsion system (250) for an aircraft comprising a frame, a propeller (152) rotatable about an axis of rotation (X), a main gear (220) fixed to the propeller (152), an electric generator (202), at least one linear electric motor (208a-b) comprising a fixed element (210) and a sliding element (212) movable in translation, for each linear electric motor (208a-b), a secondary gear (214a-b) meshing with the main gear (220) and mounted to rotate about an axis of rotation perpendicular to the axis of rotation (X), and a connecting rod (216) one end of which is articulated on the corresponding sliding element (212) and the other end of which is articulated on the corresponding secondary gear (214a-b) at a joint offset from the axis of rotation of said secondary gear (214a-b).With such a transmission system, it is possible to use linear electric motors and a gear train with a precise speed ratio.