Aircraft Engine Thrust Control in No Dwell Zone
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft engines face issues with vibration resonance modes in no dwell zones, leading to potential engine damage and thrust reduction, necessitating a system to control engines and thrust continuously across the entire operational range without increasing vibrations.
Innovation Solution
An engine electronic controller system that communicates with both engines to adjust compressor fan speeds, directing one engine to operate below the lower boundary and the other above the upper boundary of the no dwell zone, ensuring the overall average thrust remains within the zone, thereby preventing increased vibrations and allowing continuous operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the engine operates continuously within the no dwell zone to maintain average thrust, then the aircraft can operate across the entire thrust range as required by FAA regulations, but the individual engine compressor fan speeds will be at the boundaries of the no dwell zone where vibration resonance modes occur
Solution Approach 1:
The system divides the thrust production task between two engines, with each engine operating at different compressor fan speeds. One engine operates below the no dwell zone while the other operates above it, segmenting the operation to avoid the harmful resonance zone while maintaining the required average thrust
Solution Approach 2:
Each engine is assigned a different operational characteristic (one below NDZ, one above NDZ) to achieve the desired local effect. This asymmetric assignment allows the pair to produce average thrust within the NDZ while individual engines operate in safer zones, addressing the local vibration issue through differentiated engine operation
2Object-affected harmful factors
If the engine avoids operating in the no dwell zone by staying at compressor fan speed boundaries, then vibration resonance is reduced, but the engine cannot produce thrust levels corresponding to speeds within the no dwell zone range
Solution Approach 1:
The system merges the thrust output of two engines operating at different speeds to achieve the desired average thrust level. By combining one engine operating below the NDZ with another operating above the NDZ, the system produces an average thrust that corresponds to speeds within the NDZ while avoiding the harmful resonance effects
Solution Approach 2:
The thrust production system uses a composite approach by combining two different engine operating modes (one below NDZ, one above NDZ) to create a composite thrust output that achieves the desired performance characteristics without the harmful effects of operating individually within the resonance zone
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
Enables the aircraft to operate continuously within the no dwell zone without experiencing increasing vibrations, maintaining stable thrust and preventing engine damage, as demonstrated by the graphical representation of engine thrust versus compressor fan speed.
Implementation Method 1
the compressor spools of turbojet engines will experience one or more vibration resonance modes that occur in one or more operating ranges or zones between engine idle and maximum thrust
Data Source
Figure 1~2
Figure 3~4
Figure 5
AI summary
Aircraft, engine electronic controller systems, and methods for controlling thrust in a no dwell zone are provided. An aircraft includes a first engine that includes a first compressor fan rotating at a first speed and a second engine that includes a second compressor fan rotating at a second speed. First and second engine electronic controllers receive engine thrust commands and are in communication with the first and second engines, respectively. When the engine thrust commands correspond to an engine response within a no dwell zone, the first engine electronic controller directs the first engine to have the first speed at or below a compressor fan speed lower boundary and the second engine electronic controller directs the second engine to have the second speed at or above the compressor fan speed upper boundary to produce an overall average thrust within the no dwell zone.