Multi-Engine Motoring Synchronization via FADEC Control
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Solution Overview
Problem
Gas turbine engines face challenges in synchronizing the timing of starter use during multi-engine motoring, leading to variations that can cause maintenance concerns and potential damage from bowed rotor conditions due to thermal expansion and resonance issues.
Innovation Solution
A method is implemented where a controller adjusts the motoring time of one engine relative to others based on a tolerance, using a dry motoring process to maintain spool speed below resonance, synchronizing timing across engines through FADEC systems and engine control interfaces to ensure consistent motoring times and mitigate bowed rotor risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If motoring is performed separately for each engine at different times, then each engine can be cooled individually to mitigate bowed rotor conditions, but timing variations occur that are distracting to flight crews and raise unwarranted maintenance concerns
Solution Approach 1:
The patent combines the motoring operations of multiple engines to occur simultaneously rather than separately. The system coordinates the starter systems of multiple engines to perform motoring at the same time, eliminating timing variations between engines while maintaining the bowed rotor mitigation benefits. This merging approach ensures uniform timing across all engines without requiring separate sequential operations.
2Adaptability or versatility
If motoring times are not synchronized across multiple engines, then each engine can operate independently, but variations in motoring demands between engines create operational inconsistencies
Solution Approach 1:
The system uses feedback mechanisms where each engine's FADEC monitors its own motoring requirements and communicates with other engine control systems. The controllers exchange information about motoring status and adjust timing to achieve synchronization. This feedback loop allows the system to maintain independent engine operation capabilities while achieving coordinated timing through continuous monitoring and adjustment based on real-time engine conditions.
3Reliability
If extended motoring time is used to cool engines and prevent bowed rotor conditions, then engine safety is improved, but the motoring sequence becomes more complex to coordinate across multiple engines
Solution Approach 1:
The patent implements a universal control approach where the FADEC systems of multiple engines perform the same motoring coordination function simultaneously. Each engine's control system is designed to handle both its own motoring requirements and the coordination with other engines, making the system multi-functional. This universal design simplifies the overall coordination complexity by using identical control logic across all engines rather than requiring complex centralized scheduling.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively synchronizes motoring times across multiple engines, reducing the risk of bowed rotor conditions and maintaining engine safety by ensuring all engines perform motoring for the same duration, thus preventing damage and minimizing maintenance concerns.
Implementation Method 1
When the gas turbine engine of an airplane has been shut off for example, after an airplane has landed at an airport, the engine is hot and due to heat rise, the upper portions of the engine will be hotter than lower portions of the engine. When this occurs thermal expansion may cause deflection of components of the engine which may result in a 'bowed rotor' condition.
Data Source
AI summary
An aspect includes a method for motoring control for multiple engines of an aircraft is provided. A controller can determine a motoring time of a first engine starting system to cool a first engine. The controller can compare the motoring time of the first engine starting system with a motoring time of one or more other engine starting systems of one or more other engines of the aircraft. The motoring time of the first engine starting system can be controlled relative to a tolerance of the motoring time of the one or more other engine starting systems by adjusting the motoring time of the first engine starting system relative to the one or more other engine starting systems in a motoring sequence based on comparing the motoring time of the first engine starting system with the motoring time of the one or more other engine starting systems.