Thrust Reverser Hydraulic Control Valve Pressure Management
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Solution Overview
Problem
Existing thrust reverser control systems for nacelles suffer from undesirable closure cycles and structural fatigue due to over-stowing mechanisms, particularly in hydraulic locking systems, which lead to excessive load on locking devices during operation.
Innovation Solution
A hydraulic control system for thrust reversers that eliminates over-stowing by using a central control valve, first and second control valves, and a spool control valve to manage pressure differences, allowing parallel actuation of maneuvering actuators and locking/unlocking devices without direct pressurization, thereby reducing fatigue and load on locking mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If over-stowing mechanism is used in hydraulic locking system, then locking device can be unlocked under load, but structural fatigue and operational loads increase
Solution Approach 1:
The patent extracts and eliminates the over-stowing mechanism from the hydraulic control system. By removing this component and its associated pressurization step, the system achieves direct parallel actuation of maneuvering actuators and locking/unlocking devices without the harmful over-stowing action that causes structural fatigue and excessive operational loads.
Solution Approach 2:
The patent implements preliminary parallel actuation where maneuvering actuators and locking/unlocking devices are actuated simultaneously rather than sequentially. This preliminary parallel action eliminates the need for over-stowing and prevents the closure cycle that causes fatigue, while still ensuring reliable locking under load through the locking device's inherent capability.
2Reliability
If sequential actuation with over-stowing is used, then locking device operates reliably, but closure cycle causes excessive load on locking devices
Solution Approach 1:
The patent applies preliminary parallel actuation where both maneuvering actuators and locking/unlocking devices are activated simultaneously at the beginning of the operation sequence. This preliminary parallel action ensures that locking devices are not subjected to excessive closure cycle loads, while maintaining reliable locking operation through the locking device's design that allows operation under load without requiring over-stowing.
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 effectively controls thrust reverser doors without over-stowing, reducing structural fatigue and operational loads, ensuring efficient and reliable operation by decoupling pressurization from unlocking steps and utilizing a spool control valve to manage pressure differences between control valves.
Implementation Method 1
The spool control valve is configured so that the pressure difference between the two inlets of the first and second control valves provides the displacement of the spool of the spool control valve between a first stable position and a second stable position
Implementation Method 2
A hydraulic control system for thrust reversers that eliminates over-stowing by using a central control valve, first and second control valves, and a spool control valve to manage pressure differences
Data Source
AI summary
A control system includes an actuator, a locking/unlock device, a central control valve, first and second control valves, and a spool control valve. The actuator is arranged so as to move a door of a thrust reverser between direct jet and reverse jet positions. The locking/unlocking device unlockable under load allowing locking and/or unlocking of the door. The locking/unlocking device is movable between a closure position in which it holds the door in the direct jet position and an opening position in which the door is released. The first and second control valves each fed by the central control valve. The spool control valve fed at least by the first and second control valves. The spool control valve is configured so that a pressure difference between two inlets of the first and second control valves provides a displacement of the spool control valve between first and second stable positions.