Aircraft Engine Air Flow Rate Determination Method
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Solution Overview
Problem
Current methods for evaluating air flow from an aircraft engine lack precision, leading to potential engine malfunction during air sampling for cabin pressurization or de-icing, as they do not accurately adjust the fuel injection flow, risking engine unscrewing or loss of pumping protection.
Innovation Solution
A method that combines real-time estimation of air flow using physical quantity measurements, error correction, and hybridization of flow data to determine the most accurate air flow rate, ensuring precise air flow evaluation and adjustment of fuel flow thresholds to maintain a safe acceleration margin.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If air flow rate is overestimated, then the acceleration stop is overly raised, but this causes loss of pumping protection during acceleration
Solution Approach 1:
The system continuously monitors the actual air flow rate and compares it with the estimated value, using feedback to adjust the acceleration stop threshold dynamically. This ensures that the threshold is always appropriate for current operating conditions, preventing both overestimation and underestimation errors.
Solution Approach 2:
The system performs preliminary estimation of air flow rate using available sensors and models before finalizing the acceleration stop threshold. This preliminary action allows for proactive adjustment of the threshold before acceleration events occur, ensuring safety margins are maintained.
2Measurement precision
If air flow rate is underestimated, then the acceleration stop is not sufficiently raised, but this leads to risk of engine unscrewing during acceleration
Solution Approach 1:
The system uses feedback from multiple sensors and real-time monitoring to continuously refine the air flow rate estimation, ensuring that the acceleration stop threshold is never set too low. This feedback mechanism prevents underestimation errors that could lead to engine unscrewing.
Solution Approach 2:
The system incorporates safety margins and cushioning factors into the acceleration stop calculation to account for potential underestimation of air flow rate. This beforehand cushioning ensures that even if the estimation is slightly off, the engine remains protected from unscrewing conditions.
3Power
If fuel injection flow rate is increased to compensate for air bleeding, then engine thrust is maintained, but this may exceed fuel flow limits and cause engine malfunction
Solution Approach 1:
The system monitors fuel flow rate in real-time and uses feedback to adjust the injection strategy, ensuring that thrust is maintained while staying within safe fuel flow limits. This prevents engine malfunction by avoiding excessive fuel injection.
Solution Approach 2:
The fuel injection flow rate is dynamically adjusted based on current operating conditions, air flow rate estimation, and acceleration demands. This dynamic control allows the system to optimize thrust while adapting to changing conditions to avoid exceeding fuel flow limits.
Data Source
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AI summary
The invention relates to a method and to a device for determining, in real time, the flow rate of air collected from an aircraft engine (39) by a system (1) for collecting air from the engine, comprising: acquisition means (33) for acquiring, at consecutive times, the measurements of physical quantities of temperature, pressure and load loss, which are specific to the air collection system (1); calculating means (35) for evaluating, at each current time of said consecutive times, a first current estimation (Wi) of the flow of air collected from the aircraft engine (39) on the basis of said physical quantities; acquisition means (33) for acquiring at said current time a current data item (WECS) for the minimum air flow rate defined on the basis of the predetermined flow rate tables and as a function of the altitude of the aircraft; calculation means (35) suitable for selecting, at said current time, the first current estimation of the air flow rate or said current data item of the minimum air flow rate in order to form a second current air flow rate estimation (W2), said selection being performed as a function of the precision of the first current estimation.