Acoustic Shield Air Gap Thermal Protection
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Solution Overview
Problem
Existing acoustic protection screens for motor vehicle engines face issues with fluid absorption due to their porous nature, difficult metal sheet fixation leading to thermal bridges, and unprotected heat extraction openings, which can cause degradation and water ingress.
Innovation Solution
A thermo-compressed shell with a metal sheet fixed in a leaktight manner around its periphery to create an air gap, minimizing thermal bridges and preventing fluid penetration, with optional embossing for increased air gap thickness and micro-perforations for sound absorption and fluid impermeability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the metal sheet is fixed directly to the porous shell, then fixation is achieved, but thermal bridges are created causing heat degradation of the shell
Solution Approach 1:
A leaktight sealing element (gasket) is introduced as an intermediary between the metal sheet and the porous shell. This sealing element prevents direct thermal contact while maintaining fixation, thereby eliminating thermal bridges that would otherwise cause heat degradation of the shell material.
Solution Approach 2:
The thermal contact interface is extracted from the fixation system. Instead of fixing the metal sheet directly to the shell, the sheet is fixed to the sealing element, which is then mounted on the shell. This separation removes the harmful thermal conduction path while preserving the mechanical fixation function.
2Reliability
If the shell is made porous for sound absorption, then acoustic properties are improved, but fluid pick-up increases causing degradation
Solution Approach 1:
The leaktight sealing element acts as a protective intermediary that covers the porous surface of the shell at the fixation perimeter. This prevents fluid from penetrating into the porous structure while maintaining the sound absorption properties of the exposed porous areas.
Solution Approach 2:
A flexible leaktight sealing element (gasket) is used to create a fluid barrier over the porous shell surface. This thin film structure prevents fluid ingress into the porous material while allowing the shell to maintain its acoustic absorption functionality in non-sealed areas.
3Volume of moving object
If the air gap is made very thin for minimal thickness, then the screen adapts to small spaces, but heat protection effectiveness is reduced
Solution Approach 1:
The leaktight sealing element serves as a thermal intermediary that blocks direct heat conduction paths. Even with a minimal air gap thickness, the sealing element prevents hot gases or fluids from contacting the shell edge directly, maintaining heat protection effectiveness in compact spaces.
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 protects the shell from heat and fluid ingress, reduces thermal bridge degradation, and ensures robust fixation, even in areas exposed to water, while maintaining sound absorption properties.
Implementation Method 1
preserve, outside the periphery, an air gap 8 between said sheet and said shell, in order to protect said shell from the heat accumulated by said sheet
Implementation Method 2
a thermo-compressed shell based on fibers bonded together by a thermoplastic binder, so as to form a porous shell provided with sound absorption properties
Data Source
Figure 1~2
Figure 3
AI summary
The invention relates to a screen (1) comprising:a thermo-compressed shell (2) based on fibres bound together by a thermoplastic binder so as to form a porous shell that has noise absorption properties, the said shell comprising an internal face (3) and an external face (4); a sheet (5) of metal for thermal protection against the said engine, the said sheet covering all or part of the said internal face, the said sheet being attached in a substantially fluidtight manner, essentially via its periphery (6) to the said shell, so as to create a peripheral seal and maintain, except at the periphery, an air gap (8) between the said sheet and the said shell, so as to protect the said shell from the heat accumulated by the said sheet.