FADEC Pressure Spike Filter for Gas Turbine Surge Detection
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Solution Overview
Problem
False pressure sensor indications in gas turbine engines can lead to unnecessary operational responses, such as reducing engine thrust, which complicates aircraft operations and should be minimized.
Innovation Solution
A pressure spike filter algorithm is implemented in the Full Authority Digital Engine Control (FADEC) system, where digital pressure sensors from channels A and B communicate across various sections of the engine, filtering out erroneous pressure measurements by dividing the measured pressure rate of change by the average pressure and comparing the result to predetermined values to prevent false surge detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If pressure sensor indications are used for surge detection, then engine surge can be detected and recovery sequence can be triggered, but false pressure sensor indications may cause unnecessary operational responses that reduce engine thrust
Solution Approach 1:
The patent introduces an intermediary filtering algorithm between the pressure sensor and the surge detection logic. This algorithm processes the raw pressure sensor signal and generates a filtered surge detection signal, acting as a mediator that prevents false indications from directly triggering unnecessary operational responses while still allowing genuine surge conditions to be detected.
Solution Approach 2:
The system uses feedback from dual pressure sensors (P1 and P2) to continuously monitor pressure differentials and adjust surge detection decisions. The filtered surge detection signal feeds back into the control system to modulate the command exhaust area, creating a closed-loop control that reduces false activations while maintaining responsive surge protection.
2Reliability
If pressure spike filtering is applied to prevent false surge detection, then false operational responses are minimized, but detection response time may be delayed
Solution Approach 1:
The filtering algorithm applies partial filtering by selectively attenuating certain frequency components of the pressure signal while preserving others. Rather than completely filtering out all high-frequency content, the algorithm applies just enough filtering to reduce false detections while maintaining the response speed necessary for genuine surge detection.
Solution Approach 2:
The filter characteristics are dynamically adjusted based on operating conditions. The filtering algorithm adapts its parameters according to the current engine state, allowing faster response when the engine is in conditions prone to surge while applying stronger filtering when false detections are more likely, thus balancing reliability and response speed.
Data Source
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AI summary
A filter algorithm for a dual channel electronic engine control system according to one disclosed non-limiting embodiment of the present disclosure includes a division function that divides a measured pressure rate of change of one of a FADEC channel A and FADEC channel B by an average pressure of the FADEC channel A and the FADEC channel B to obtain a resultant value; a first comparator function to bound a proper high resultant value from the division function; a second comparator function to bound a proper low resultant value from the division function; and an OR gate in communication with the first comparator and the second comparator such that if an output from either the first comparator function and the second comparator function is true, that one of the FADEC channel A and the FADEC channel B is filtered out for a time period.