Fuel Metering Device Sensor Redundancy Control
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Solution Overview
Problem
The existing fuel metering systems in turbomachines face issues with sudden power drops due to sensor malfunctions, leading to temporary deviations in fuel flow rates and power delivery, which are undesirable for optimal performance.
Innovation Solution
A method and system for controlling a fuel metering device with a movable metering element that detects changes in sensor states, calculates instantaneous fuel flow rates, and adjusts the flow rate setpoints to maintain consistent position setpoints, preventing deviations and ensuring constant power delivery by averaging or selecting functional sensor measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If two position sensors are used to measure the slide position, then measurement reliability is improved through redundancy, but system complexity increases
Solution Approach 1:
The system divides the measurement function into two independent position sensors, each measuring the slide position separately. This segmentation provides redundancy so that if one sensor fails, the other can still provide measurements, thereby improving reliability without requiring a completely different measurement approach
Solution Approach 2:
The control system continuously monitors both sensor measurements and compares them to detect discrepancies before they cause significant control errors. By performing this comparison in advance, the system can identify sensor malfunctions early and switch to using only the functional sensor, preventing power drops before they occur
2Reliability
If sensor malfunction detection is implemented, then system reliability is improved, but control loop complexity increases
Solution Approach 1:
The system implements a feedback mechanism where the measured slide position is continuously compared against the commanded position. When a discrepancy exceeds a threshold, the system detects a potential sensor malfunction and adjusts the control strategy accordingly. This feedback loop enables automatic detection and response to sensor failures without requiring complex external monitoring systems
Solution Approach 2:
The control system dynamically changes its operating parameters based on sensor health status. When both sensors are functional, the system uses averaged measurements for improved accuracy. When a malfunction is detected, the system switches to using only the functional sensor and adjusts the control law accordingly, thereby maintaining stability without requiring a complete redesign of the control architecture
3Measurement precision
If slide position determination uses sensor averaging, then measurement accuracy is improved, but response time decreases when sensor malfunction occurs
Solution Approach 1:
The system dynamically adjusts its measurement strategy based on real-time sensor performance. When both sensors are functioning normally, the system uses averaged measurements from both sensors to improve precision. When a sensor malfunction is detected, the system immediately switches to using only the functional sensor, thereby maintaining adequate measurement precision while avoiding the delays that would occur with gradual fallback mechanisms
Data Source
AI summary
A method for controlling a fuel metering device with a movable metering element, comprising at least two iterations of the following steps:a detection (E1) of a possible change in the operating state among two position sensors of the metering element, if no change in the operating state is detected, a determination (E2_1) of the position of the metering element from an average of the measurements of the sensors or otherwise a determination (E2_2) from the non-defective sensor,a determination (E4) of a fuel flow rate setpoint, a conversion (E5) of the flow rate setpoint,a determination (E6) of a command of displacement of the metering element, a control (E7) of the position of the metering element, andif a change in the operating state is detected, the calculation of an instantaneous fuel flow rate from the position of the metering element, and, during the second iteration of the method, the determination of the flow rate setpoint according to instantaneous flow rate to match the position setpoint to the position of the metering element.