Aircraft Brake Return-Line Pressurization to Prevent Cavitation
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Solution Overview
Problem
Hydraulic systems in aircraft brake systems experience false fault reports and inefficiencies due to cavitation in return lines, particularly during pre-land tests, which can lead to unnecessary maintenance and operational delays.
Innovation Solution
A method and system that increase the pressure and/or volume of hydraulic fluid in the return line before activating the brake system, using valves and accumulators to prevent cavitation and ensure adequate fluid retention, thereby reducing false fault reports and improving system reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic fluid pressure is increased in the return line, then cavitation is prevented, but additional system complexity is required
Solution Approach 1:
The system uses existing hydraulic components (valves and accumulators already present in the brake system) to increase fluid pressure in the return line. The brake system itself provides the means to prevent cavitation without requiring external or additional specialized equipment, thereby maintaining simplicity.
2Quantity of substance
If the return line is pressurized before testing, then fluid retention is improved, but test timing and procedure complexity increases
Solution Approach 1:
The system increases fluid pressure in the return line as a preliminary step before the actual brake test. This ensures adequate fluid retention and prevents cavitation during testing, while the automated nature of the process minimizes the time penalty associated with this preparation step.
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
Enhances the reliability of brake system tests by preventing cavitation in return lines, reducing false fault indications, and ensuring efficient brake operation during critical phases.
Implementation Method 1
a step of increasing the pressure and/or volume of hydraulic fluid in at least a portion of the return line
Implementation Method 2
Return lines 38 (not all of which being shown in Figure 1) for the releasing of pressure from the brakes 16 are provided. Hydraulic fluid passes via the return lines 38 through the valves, at lower pressure, to the aircraft's hydraulic circuits
Data Source
Figure 1
Figure 2
Figure 3
AI summary
An aircraft brake system (210) comprises a supply line for supplying hydraulic fluid to wheel brakes (216), and an associated return line (238). Hydraulic fluid is replenished in at least a portion of the return line both (a) before applying a braking force to the one or more wheels of the aircraft during landing and (b) before an intervening, optional, step if so performed of testing the brake system before landing of the aircraft. Replenishing the hydraulic fluid may be conducted by a control unit (214) automatically and/or in response to a pressure drop in the return line measure by a transducer (244).