Staggered Engine Speed Control for Multi-Engine Aircraft Vibration
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Solution Overview
Problem
Existing aircraft engine vibration monitoring systems fail to effectively manage engine speed to prevent excessive vibrations caused by certain weather conditions, leading to cabin noise, comfort issues, and pilot workload fluctuations.
Innovation Solution
A method and system for controlling engine speed in multi-engine aircraft by monitoring thrust requests and determining corresponding engine speeds, allowing one engine to transition through a selected speed range while holding the other outside of it, using staggered thresholds and operation modes dependent on flight phase and ambient conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If engine speed is controlled to avoid certain speed bands to minimize vibrations, then engine vibration levels are reduced, but cabin noise and aircraft speed fluctuations increase
Solution Approach 1:
The patent segments the engine fleet into multiple groups (e.g., left engine and right engine) and applies different speed control strategies to each group. When one engine is restricted from operating in a problematic speed band, the other engine can operate freely, ensuring thrust compensation is possible without excessive cabin noise or aircraft speed fluctuations.
Solution Approach 2:
The patent dynamically changes the operating parameters (speed limits, thrust restrictions) of individual engines based on real-time conditions. By adjusting which engine is constrained and by how much, the system minimizes vibrations while maintaining acceptable cabin noise levels and aircraft performance.
2Reliability
If engine speed is restricted to avoid high fan imbalance, then engine vibrations are minimized, but pilot workload and operational complexity increase
Solution Approach 1:
The patent implements an automated engine speed control system that independently manages engine operations without requiring pilot intervention. The FADEC (Full Authority Digital Engine Control) systems automatically adjust engine speeds, apply thrust restrictions, and coordinate between engines to avoid problematic speed bands, thereby reducing pilot workload while maintaining vibration control.
Solution Approach 2:
The system continuously monitors engine performance parameters, vibration levels, and speed band conditions, then uses this feedback to automatically adjust engine operating parameters. This closed-loop control eliminates the need for manual pilot adjustments and reduces operational complexity.
3Productivity
If both engines are allowed to operate freely, then aircraft thrust and speed are maintained, but excessive vibrations occur in certain weather conditions
Solution Approach 1:
The patent divides the engine control into segmented groups where one engine can be restricted while the other operates freely. This segmentation allows the system to maintain overall aircraft thrust by compensating for the restricted engine's limitations with the other engine, while still avoiding the harmful vibrations that would occur if both engines operated in the problematic speed band simultaneously.
Solution Approach 2:
The system dynamically adjusts engine operating parameters based on real-time conditions including weather, aircraft speed, and vibration levels. This dynamic control allows the aircraft to maintain required thrust levels while adaptively avoiding speed bands that would cause excessive vibrations under current operating conditions.
Data Source
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AI summary
Method (500) and system for controlling engine speed in a multi-engine aircraft, comprising monitoring a request for a first engine (100A) and a second engine (100B) to generate a given thrust and determining a corresponding engine speed (306) for the first engine (100A) and the second engine (100B) in accordance with the given thrust. When the corresponding engine speed (306) is outside of a selected speed range, a first engine speed (308) and a second engine speed (310) are allowed to track the corresponding engine speed (306). When the corresponding engine speed (306) is within the selected speed range, a transition of the first engine speed (308) and the second engine speed (310) through the selected speed range is staggered by allowing one of the first engine speed (308) and the second engine speed (310) to transition through the selected speed range while holding the other of the first engine speed (308) and the second engine speed (310) outside of the selected speed range.