Funnel Membrane Sound Generator for Exhaust Noise Cancellation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing anti-noise systems for internal combustion engine vehicles face challenges in reducing exhaust and intake noises due to the large volume required for effective sound wave cancellation, which increases resistance and fuel consumption, and poses thermal stress issues for loudspeakers.
Innovation Solution
A compact sound generator design featuring a funnel-like or dome-shaped membrane that allows for a reduced enclosure volume while maintaining high sound energy flux, with a bell mouth connection to the exhaust or intake system, protecting sensitive components from thermal stress and corrosive gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a large volume enclosure is used for effective sound wave cancellation, then acoustic performance is improved, but construction volume increases and resistance to exhaust gases increases
Solution Approach 1:
The patent employs a funnel-like membrane with curved surface geometry instead of a conventional planar diaphragm. This curved configuration allows the membrane to expand into the exhaust flow more effectively, increasing the active surface area for sound wave generation without proportionally increasing the enclosure volume. The curvature enables better acoustic coupling with the exhaust gases while maintaining a compact overall structure.
Solution Approach 2:
The invention transitions from a two-dimensional planar membrane to a three-dimensional funnel-like structure that protrudes into the exhaust flow. This dimensional change allows the membrane to utilize the exhaust flow space more efficiently, creating sound waves in a direction that is more effective for noise cancellation while reducing the required enclosure volume.
2Reliability
If a large volume enclosure is used for effective sound wave cancellation, then acoustic performance is improved, but resistance to exhaust gases increases resulting in increased fuel consumption
Solution Approach 1:
The funnel-like curved membrane reduces the enclosure volume required for effective noise cancellation, thereby reducing the resistance to exhaust flow. This lower resistance decreases the energy loss and fuel consumption compared to larger conventional enclosures while maintaining the necessary acoustic performance for effective sound wave cancellation.
3Power
If loudspeaker components are placed close to exhaust system, then sound energy flux is improved, but thermal stress on components increases
Solution Approach 1:
The funnel-like membrane acts as an intermediary between the loudspeaker components and the exhaust flow. It allows the components to be positioned closer to the exhaust system for improved sound energy flux while the funnel geometry provides a degree of thermal management by directing exhaust flow around rather than directly against the sensitive components.
Solution Approach 2:
The membrane serves as a flexible barrier that separates the thermal environment of the exhaust system from the sensitive loudspeaker components. This thin film structure allows acoustic energy to pass through while providing thermal protection to the components.
4Power
If loudspeaker components are placed close to exhaust system, then sound energy flux is improved, but risk of thermal damage to components increases
Solution Approach 1:
The funnel-like membrane and enclosure structure serve as protective intermediaries that enable close positioning of components to the exhaust system for improved sound energy flux while protecting against thermal damage. The geometry allows exhaust gases to flow around the components rather than directly impinging on them.
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 compact design enhances acoustic performance by reducing construction volume while maintaining sound energy flux, improving installation depth and reducing the risk of thermal damage to components.
Implementation Method 1
Respective systems are for instance known from the following documents: U.S. Pat. Nos. 4,177,874, 5,229,556, 5,233,137, 5,343,533,5,336,856, 5,432,857, 5,600,106, 5,619,020
Implementation Method 2
a membrane which is funnel-like (funnel shaped), and in particular non developable
Data Source
AI summary
A sound generator for influencing sound waves propagating in exhaust or intake systems of combustion engine driven vehicles includes: an enclosure having a port opening for communication with an exhaust and/or intake system; a loudspeaker basket supported by the enclosure; a membrane and a permanent magnet supported by the loudspeaker basket; and a voice coil supported by a voice coil carrier. The voice coil is disposed in a constant magnetic field created by the permanent magnet and is connected to the membrane. The membrane is located between the port opening and the permanent magnet. The membrane is funnel-like or dome-like, with the top or top face of the funnel-like membrane or the geometric center of the dome-like membrane facing away from the permanent magnet. An anti-noise system using the sound generator, and a vehicle using the anti-noise system are also provided.