Active Vibration Cancellation in Aircraft Engine Mounts
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Aircraft cabin tonal noise is generated by engine vibrations due to residual imbalances in rotating components, which propagate through the wing and fuselage, causing low-frequency noise that can lead to passenger fatigue and increased noise penalties, and existing soft engine mounts are unreliable and undesirable for large commercial aircraft.
Innovation Solution
Active vibration mechanisms, such as powered actuators, are attached to engine mounts to monitor and cancel or dissipate tonal vibrations by injecting anti-vibration movements or dynamic energy absorbers, using sensors to determine fundamental frequencies and generate counteracting signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If soft engine mounts are used to reduce vibration transmission, then vibration isolation is improved, but reliability and durability deteriorate
Solution Approach 1:
The system separates the vibration isolation function from the mounting structure by adding independent active vibration mechanisms (actuators) to the existing hard mount, rather than replacing the mount with a soft isolator. This segmentation allows the hard mount to maintain structural reliability while the active mechanisms handle vibration cancellation.
Solution Approach 2:
The patent replaces the passive mechanical vibration isolation of soft mounts with an active control system using powered actuators that generate counter-vibrations. This substitution maintains the mechanical simplicity and reliability of hard mounts while achieving vibration isolation through electronic control and actuation.
2Object-affected harmful factors
If soft engine mounts are used to reduce vibration transmission, then vibration isolation is improved, but displacement during engine speed up increases
Solution Approach 1:
The system separates the static support function (handled by the hard mount with minimal displacement) from the dynamic vibration cancellation function (handled by active actuators). This allows the mount to remain rigid during engine speed-up while active mechanisms cancel vibrations at operating speeds.
Solution Approach 2:
The active vibration mechanisms are dynamically activated based on engine operating conditions, providing vibration cancellation when needed while maintaining the static rigidity of the hard mount during transient operations like engine speed-up.
3Reliability
If hard engine mounts are used to maintain reliability, then reliability is improved, but vibration transmission increases
Solution Approach 1:
The system merges the advantages of hard mounts (reliability, durability, low displacement) with active vibration control mechanisms. The hard mount provides reliable mechanical support while integrated actuators actively cancel vibrations, combining the benefits of both hard and soft mount approaches.
Solution Approach 2:
The patent substitutes the passive mechanical vibration isolation of soft mounts with an active control system that uses sensors and actuators to generate counter-vibrations, thereby maintaining the reliability of hard mounts while eliminating their vibration transmission drawback.
4Object-affected harmful factors
If active vibration mechanisms are added to cancel vibrations, then vibration isolation is improved, but device complexity increases
Solution Approach 1:
The active vibration mechanisms are integrated into the existing engine mount structure, allowing the mount to serve both mechanical support and vibration cancellation functions. This multi-functionality reduces the need for separate components and minimizes overall system complexity.
Solution Approach 2:
The system uses sensors mounted on the engine and fuselage to automatically detect vibrations and triggers the actuators to generate counter-vibrations without external intervention. This self-regulating control system reduces the need for complex external control mechanisms.
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
The solution effectively reduces vibration transmissibility and noise levels by minimizing the amplification of engine vibrations, providing a reliable alternative to traditional soft mounts while maintaining low displacement during engine operation.
Implementation Method 1
powered actuators attached to the structure in the vicinity of, or embedded within, the engine mount to inject anti-vibration movements to cancel the tonal vibrations generated by the engine
Implementation Method 2
vibration sensors are placed on the engine and/or fuselage and/or wing structure to monitor the vibration performance of the engine and engine mount structure
Data Source
AI summary
An engine mount structure is provided with active vibration mechanisms which are attached in the vicinity of the engine mount to prevent engine vibrations from propagating into the engine mounting structure, for example, the wing or fuselage structure of an aircraft. Additionally, sensors are provided on the engine and/or wing/fuselage structure to provide control signals to the active vibration mechanisms so that the active vibration mechanism react to the sensed data to minimize the vibration transmissibility from the engine into the wing/fuselage.