Uncontrolled High Thrust Detection in Turbofan Engines
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Solution Overview
Problem
Current systems rely heavily on crew recognition to detect uncontrolled high thrust conditions in gas turbine engines, which is not always reliable, leading to potential engine damage or loss of power.
Innovation Solution
A system and method that processes data to determine when the commanded fan speed exceeds a predetermined value, generating an alert when the actual engine fan speed exceeds a target speed by a predetermined amount for a preset time, thereby autonomously detecting uncontrolled high thrust conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If crew recognition is used to detect uncontrolled high thrust conditions, then the system complexity is low, but the reliability of detection is insufficient
Solution Approach 1:
The engine control system automatically monitors its own operational parameters (commanded fan speed vs actual fan speed) and self-diagnoses uncontrolled high thrust conditions without requiring external human intervention, thereby improving detection reliability while maintaining reasonable system complexity
Solution Approach 2:
The system continuously compares actual fan speed feedback against commanded fan speed values and generates alerts when discrepancies exceed predetermined thresholds, creating a closed-loop monitoring mechanism that enhances detection reliability through automated feedback analysis
2Reliability
If automated detection system is implemented, then the reliability of detection is improved, but the device complexity increases
Solution Approach 1:
The engine control system performs multiple functions including normal engine control, parameter monitoring, comparison operations, and uncontrolled high thrust detection within a single integrated control unit, thereby improving detection reliability without proportionally increasing overall system complexity
Solution Approach 2:
The system uses predetermined threshold values and target fan speed calculations as intermediary reference points to mediate between raw sensor data and detection decisions, simplifying the detection logic while maintaining high reliability through standardized comparison criteria
3Loss of time
If crew intervention is relied upon, then the response time is dependent on crew recognition, but the loss of power occurs when engine shutdown is necessary
Solution Approach 1:
The system continuously monitors engine parameters in advance and proactively generates alerts before uncontrolled high thrust conditions develop or escalate, enabling early intervention that preserves power availability by avoiding unnecessary engine shutdowns
Solution Approach 2:
The continuous feedback loop between commanded and actual fan speed measurements enables real-time detection and immediate alert generation, reducing response time by eliminating the delay associated with human recognition and decision-making processes
Data Source
AI summary
A system and method of detecting an uncontrolled high thrust (UHT) condition in a turbofan gas turbine engine includes processing data to determine when a current commanded fan speed value is greater than a predetermined speed value. A current UHT commanded fan speed value is processed to determine if it will cause a target fan speed value to increase, remain steady, or decrease. The target fan speed value is set equal to the current UHT commanded fan speed value when the current UHT commanded fan speed value will cause the target fan speed value to increase or remain steady, and to a deceleration threshold value when the current UHT commanded fan speed value will cause the target fan speed value to decrease. An uncontrolled high thrust alert signal is generated when actual engine fan speed exceeds the target fan speed value by a predetermined amount for a preset time period.