Variable Pitch Propeller Control Valve for Feather and Reverse
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Solution Overview
Problem
Conventional variable pitch propeller assemblies for aircraft are heavy due to the inclusion of solenoid-operated components, which penalize engine efficiency, and they lack efficient overspeed, feathering, and reverse mode functionalities without increasing weight.
Innovation Solution
A variable pitch propeller assembly incorporating a secondary electrohydraulic servovalve (EHSV) control valve that integrates overspeed protection, feathering, and reverse enabling capabilities, with features like one-way valves and a pitch lock mechanism to manage hydraulic fluid flow during oil starvation conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If solenoid-operated feather valve and ground beta enable solenoid are included, then feathering and reverse mode functionalities are enabled, but weight of the engine increases
Solution Approach 1:
The patent combines multiple control functions (overspeed protection, feathering, reverse enabling) into a single electrohydraulic servovalve (EHSV), eliminating the need for separate solenoid-operated feather valve and ground beta enable solenoid. This integration reduces component count and overall weight while maintaining all required functionalities.
Solution Approach 2:
The electrohydraulic servovalve is designed to perform multiple functions: overspeed protection, feathering mode activation, and reverse mode enabling. This multi-functional component replaces several specialized solenoid-operated components, reducing total weight while providing comprehensive control capabilities.
2Ease of operation
If conventional solenoid-operated components are used, then pitch control functionality is achieved, but engine efficiency is penalized due to increased weight
Solution Approach 1:
The patent integrates multiple pitch control functions into a single electrohydraulic servovalve, reducing the total weight of control components. This weight reduction directly improves engine efficiency by decreasing the rotating mass that the engine must accelerate and decelerate, while maintaining full pitch control functionality.
3Adaptability or versatility
If multiple separate valves and solenoids are used for overspeed protection, feathering, and reverse mode, then comprehensive control is achieved, but device complexity increases
Solution Approach 1:
The patent consolidates three separate control systems (overspeed protection valve, feather valve, ground beta enable valve) into a single electrohydraulic servovalve with multiple ports and control modes. This integration reduces the number of discrete components from four+ valves/solenoids to one unified component, simplifying the overall system architecture.
Solution Approach 2:
The electrohydraulic servovalve is designed as a universal control component that can perform overspeed protection, feathering, and reverse mode activation through different control signals and internal valve positions. This multi-functional design eliminates the need for multiple specialized components, reducing system complexity.
4Ease of operation
If conventional pitch control system is used, then basic pitch adjustment is achieved, but weight reduction and efficiency enhancement are limited
Solution Approach 1:
The patent replaces the conventional pitch control system with an electrohydraulic servovalve-based system that integrates multiple functions. This consolidation reduces the total weight of the propeller assembly by eliminating redundant solenoids and valves, while maintaining full pitch adjustment capability through the multi-functional EHSV.
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 solution provides efficient weight management by reducing the need for solenoids while ensuring propeller assemblies maintain onspeed conditions, enable feathering, and provide reverse thrust, enhancing engine performance and efficiency.
Implementation Method 1
the at least one electrohydraulic servovalve is operable to selectively allow a flow of hydraulic fluid to or from the propeller dome of the pitch actuation assembly
Implementation Method 2
the at least one valve is a one-way valve having an inlet fluidly coupled to the propeller dome and an outlet fluidly coupled to the inlet port of the at least one electrohydraulic servovalve
Data Source
AI summary
A variable pitch propeller assembly operatively coupled with an engine and methods for controlling the pitch of a plurality of propeller blades thereof is provided. In one example aspect, the variable pitch propeller assembly includes features for combining overspeed, feathering, and reverse functionality in a single secondary control valve. The secondary control valve is operable to selectively allow a controlled amount of hydraulic fluid to flow to or from a pitch actuation assembly such that the pitch of the propeller blades can be adjusted to operate the variable pitch propeller assembly in one of a constant speed mode, a feather mode, and a reverse mode.