Propeller Control Assembly Using Two-Position Solenoid Valve
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Solution Overview
Problem
Existing propeller control systems for aircraft engines, particularly constant speed propellers, rely heavily on costly and weight-increasing overspeed governors for backup control, necessitating a more efficient and lightweight solution.
Innovation Solution
A propeller control assembly utilizing a two-position solenoid valve and a controller that regulates fluid flow to adjust blade angles, allowing for precise control of propeller speed and preventing overspeed by selectively adding or removing fluid, with the two-position solenoid valve acting as a primary or secondary control mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an overspeed governor is used as a backup control mechanism, then propeller overspeed protection is improved, but system weight and cost increase
Solution Approach 1:
The patent extracts the essential backup control function from the traditional overspeed governor and implements it through a simplified two-position solenoid valve system. The solenoid valve selectively connects the propeller dome to either the oil supply or drain, providing the necessary overspeed protection without the complex mechanical components of a traditional governor, thereby reducing weight while maintaining reliability
Solution Approach 2:
The patent replaces the mechanical overspeed governor system with an electrically-controlled two-position solenoid valve system. The solenoid valve uses electromagnetic actuation instead of mechanical linkages and centrifugal mechanisms, eliminating the need for heavy mechanical components while achieving the same backup control function for propeller overspeed protection
2Reliability
If an overspeed governor is used as a backup control mechanism, then propeller overspeed protection is improved, but system cost increases
Solution Approach 1:
The patent employs a two-position solenoid valve that is inherently simpler and less expensive to manufacture than a traditional overspeed governor. The solenoid valve has fewer moving parts, requires less precision machining, and can be produced using standard electromagnetic component manufacturing processes, thereby reducing system cost while maintaining the necessary overspeed protection function
3Measurement precision
If a proportional valve is used to control oil flow, then propeller speed control precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the continuous control function of a proportional valve into discrete two-position control stages. The solenoid valve provides distinct positions for oil addition and oil drainage, with the controller managing the sequencing and timing of these discrete actions to achieve precise propeller speed control without requiring the continuous adjustment mechanism of a proportional valve, thereby reducing device complexity
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 solution provides precise control of propeller speed, prevents overspeed, and reduces system weight and cost by using a solenoid valve to manage fluid flow, offering a reliable and efficient alternative to traditional backup control methods.
Implementation Method 1
a two-position solenoid valve (208) used to regulate fluid flow to and from the propeller
Data Source
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AI summary
A method (400) for controlling an aircraft propeller (130) comprises obtaining a measurement of a speed (NP) of the propeller (130), comparing the propeller speed (NP) to a first threshold (NP Thresh), responsive to determining that the propeller speed (NP) exceeds the speed threshold (NP Thresh), outputting a valve control signal for opening a two-position solenoid valve (208) coupled to the propeller (130), the two-position solenoid valve (208) configured for controlling fluid flow to and from the propeller (130) to control propeller blade angle, computing a rate of change of the propeller speed (NPdot), comparing the rate of change of the propeller speed (NPdot) to a second threshold, and responsive to determining that the rate of change of the propeller speed (NPdot) is below the second threshold, outputting the valve control signal for closing the two-position solenoid valve (208). A system for controlling an aircraft propeller (130) and an aircraft propeller control assembly (200) are also provided.