Aircraft Engine Synchronization via Dual-Spool Trim
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Solution Overview
Problem
Existing engine synchronization methods for gas-turbine engines in aircraft fail to effectively synchronize low-pressure and high-pressure compressor spool speeds, leading to annoying noise beats due to slight speed differences, which are not easily adjustable and require pilot selection of synchronization methods.
Innovation Solution
A method that calculates speed differences for both low-pressure and high-pressure compressor spools, using the auto throttle trim computer to adjust settings without affecting the electronic engine controller, and utilizes the T20 value to control high-pressure spool speeds through the stator vanes, allowing synchronization without changing thrust or speed settings, and is applicable under all engine and flying conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If only low-pressure compressor spool speed is synchronized, then synchronization is achieved, but high-pressure spool runs with speed difference causing noise beats
Solution Approach 1:
The synchronization process is divided into two independent stages: first synchronizing the low-pressure compressor spool speeds, then synchronizing the high-pressure compressor spool speeds. This segmentation allows each spool to be optimized independently, eliminating the compromise required when synchronizing only one spool, thereby preventing noise beats while maintaining reliable synchronization.
2Adaptability or versatility
If pilot selects synchronization method, then adaptability is improved, but operational complexity increases
Solution Approach 1:
The aircraft's control system automatically determines and executes the appropriate synchronization method without requiring pilot selection. The system self-adjusts to synchronize both low-pressure and high-pressure spools based on operating conditions, eliminating the need for pilot intervention while maintaining adaptability to different flight regimes.
3Measurement precision
If thrust or speed settings are changed for synchronization, then synchronization precision is improved, but control loop stability is affected
Solution Approach 1:
The invention introduces an intermediary trimming value that adjusts the reference speed for synchronization without directly modifying thrust or speed settings. This intermediary parameter allows precise synchronization of both spools while maintaining the stability of the existing control loops, as the adjustment is made at the reference level rather than directly affecting the controlled variables.
Data Source
AI summary
This invention relates to an engine synchronization method for aircraft equipped with at least two gas-turbine engines, where the respective speeds N1 of the low-pressure compressor spools of the gas-turbine engines are determined and a difference value N1 is calculated and subsequently on the basis of this difference value at least one trim value is calculated, on the basis of which, at least on one gas-turbine engine, a change of the setting is made, with subsequently the respective speeds N2 of the high-pressure compressor spools of the gas-turbine engines being determined and a difference value N2 being calculated and subsequently on the basis of this difference value, at least on one gas-turbine engine, the inlet temperature value T20, which is fed to the engine controller, being changed for synchronization.