Air Cycle Machine Speed Monitoring for Bearing Failure Shutdown
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Solution Overview
Problem
Air cycle machines in aircraft systems face issues with abnormal speed fluctuations and potential surface contact due to overloading, leading to material wear and emissions that require immediate shutdown to prevent aircraft landing.
Innovation Solution
A method and apparatus that utilize a speed sensor and processor to monitor rotational speed and deceleration rates, comparing them to thresholds to prevent air cycle machine failure by shutting it down before significant wear occurs, using a system that measures rotational speed 20 times per second and determines crossing counts and sign changes to indicate impending failure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the air bearing is monitored to detect abnormal speed fluctuations, then the reliability of the air cycle machine is improved, but the device complexity increases due to additional sensors and processing systems
Solution Approach 1:
The patent implements a feedback mechanism where a speed sensor continuously monitors the rotational speed of the air cycle machine, and a processor analyzes the speed fluctuations to detect abnormal conditions. The system provides feedback by comparing measured speed variations against threshold values and triggers alerts or shutdowns when abnormal patterns are detected, enabling proactive maintenance before catastrophic failure occurs.
2Measurement precision
If the rotational speed is measured at high frequency (20 times per second), then the measurement precision of speed fluctuations is improved, but the use of energy increases due to continuous high-rate sampling
Solution Approach 1:
The patent applies partial action by measuring speed at a high rate (20 Hz) only when necessary for detecting abnormal fluctuations, rather than continuously at maximum precision. The system uses a processor to analyze whether the measured fluctuations exceed threshold values, enabling energy-efficient operation by maintaining high measurement precision only when abnormal conditions are detected or suspected.
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
Effectively prevents air cycle machine failure by accurately detecting erratic speed fluctuations and deceleration spikes, allowing for timely shutdown to avoid material wear and emissions, ensuring safe operation and preventing unnecessary aircraft landings.
Implementation Method 1
An air cycle machine includes an air bearing that uses a film of pressurized air to provide a low-friction load-bearing interface between two surfaces
Data Source
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AI summary
A method and apparatus for operating an air cycle machine is disclosed. The apparatus includes a detector 104 for measuring a rotational speed of a component of the air cycle machine 102. A processor 106 estimates a rate of change of rotational speed of the component from the measured rotational speed and shuts down the air cycle machine when the estimated rate of change of the rotational speed of the component is greater than a selected rate threshold.