Propeller Blade Orientation Circuit for Rapid Thrust Reversal Protection
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Solution Overview
Problem
Existing protection systems for aircraft engine propeller blades take approximately one second to react and prevent accidental thrust reversal during flight, which is insufficiently rapid.
Innovation Solution
A hydraulic control circuit with an amplification valve and protection valves, each equipped with return springs, rapidly changes the propeller blade orientation by connecting high-pressure and low-pressure lines to activation and deactivation inlets, ensuring quick reorientation to propulsion mode upon detection of a drift towards thrust reversal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If existing protection systems are used to prevent accidental thrust reversal, then the blades are protected from dangerous orientation drift, but the reaction time is approximately one second which is insufficiently rapid
Solution Approach 1:
The patent replaces the conventional slow mechanical/electrical protection system with a hydraulic system that uses fluid pressure to actuate protection valves. The hydraulic amplification valve rapidly redirects high-pressure fluid to the protection valves, achieving a reaction time of one-tenth of a second by exploiting the rapid compressibility and flow characteristics of hydraulic fluid rather than relying on mechanical linkages or electrical actuation speeds.
Solution Approach 2:
The invention employs a hydraulic circuit with high-pressure and low-pressure lines, an amplification valve, and protection valves that use hydraulic pressure differential to rapidly change state. When the amplification valve opens, high-pressure hydraulic fluid instantly acts on the protection valves, forcing them to switch from closed to open state in one-tenth of a second, thereby rapidly correcting blade orientation.
2Loss of time
If the hydraulic circuit is designed with amplification valve and protection valves for rapid response, then the reaction time is reduced to one-tenth of a second, but the device complexity increases
Solution Approach 1:
The amplification valve serves multiple functions: it acts as a control element that responds to pilot pressure, functions as a pressure amplifier that converts low-pressure control signals into high-pressure actuation, and serves as a timing mechanism that enables rapid response. This multi-functionality reduces the need for separate components and simplifies the overall hydraulic circuit despite the rapid response requirement.
Solution Approach 2:
The amplification valve acts as an intermediary between the low-pressure control system and the high-pressure protection valve actuation system. It mediates the transition by using a small amount of control pressure to regulate a large amount of high-pressure hydraulic fluid, thereby enabling rapid protection valve actuation without requiring a complex direct high-pressure control system.
3Reliability
If protection valves are continuously monitored and rapidly actuated, then accidental thrust reversal is prevented, but the energy consumption increases
Solution Approach 1:
The hydraulic system maintains high-pressure fluid continuously available in the high-pressure line, and the protection valves are pre-positioned and spring-loaded for immediate actuation. The amplification valve is designed to open rapidly when needed, utilizing the pre-stored hydraulic energy rather than requiring energy-intensive active control during the protection event. This preliminary preparation enables rapid response with minimal additional energy consumption.
Solution Approach 2:
The protection valves are equipped with springs that automatically return them to the closed position after actuation, and the hydraulic system self-regulates through the amplification valve's pressure differential mechanism. The system uses its own hydraulic pressure to both actuate and reset the protection valves without requiring external energy input for each cycle, thereby reducing overall energy consumption while maintaining continuous safety protection.
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 achieves a reaction time of one-tenth of a second, significantly reducing the risk of accidental thrust reversal during flight by ensuring rapid reorientation of propeller blades.
Implementation Method 1
an amplification valve (32) being able to assume a deactivated position or an activation position wherein it connects the high-pressure line (23) to each activation inlet (37, 41) and the low-pressure line (24) to each deactivation inlet (38, 42) to activate the protection valves
Implementation Method 2
a protection solenoid valve (31) being able to assume a deactivation position or an activation position wherein it connects the control inlet (46) of the amplification valve (32) to the low-pressure line (24) in order to activate it
Implementation Method 3
each protection valve (33, 34) being equipped with a return spring (36, 39) continuously tending to return it to the activation position thereof
Data Source
AI summary
A hydraulic control circuit of a steering actuator having a first and a second chamber, for orienting the blades of an aircraft engine propeller, this circuit comprising a high-pressure line and a low-pressure line, a first protection valve being able to assume a deactivated position or an activated position for placing the first chamber in communication with the high-pressure line, a second protection valve being able to assume a deactivated position or an activated position for placing the second chamber in communication with the low-pressure line, each protection valve comprising a hydraulic activation inlet and a hydraulic deactivation inlet which can be pressurised in order to activate or deactivate these valves. The circuit includes a solenoid protection valve controlling an amplification valve connected to the inlets of the protection valves in order to activate them upon the activation of the solenoid protection valve.