Acoustic protection system for motor vehicle, has fiber-like material layer presenting progressive density variation so that layer has high and low average density zones for presenting mass and spring behaviors

摘要

The system has a fiber-like material layer (1) presenting a progressive density variation according to its thickness. The density variation is such that the layer has a high average density zone (3) for presenting a mass behavior and a low average density zone (2) for presenting a spring behavior. The layer has charges dispersed within fibers in the form of mineral or metallic powder. Independent claims are also included for the following: (A) a method of producing a fiber-like material layer of an acoustic protection system (B) a motor vehicle liner such as carpet, fire wall or engine compartment sound damper, trunk liner or headlining, including an acoustic protection system.