Acoustic baffle system for e.g. internal combustion engine in car, has ambient air layer acoustically coupling subassembly to another subassembly, where latter subassembly has rigid wall provided with perforations and fixed on engine head

摘要

The system has a sub assembly that is constituted of a vehicle bonnet (a) carrying a sound insulating layer (b) made of felt. Another sub assembly is constituted by an ambient air layer (c) acoustically coupling the former subassembly to a third subassembly. The third subassembly e.g. perforated plastic shell or plate, is constituted of a perforated rigid wall (d) provided with perforations (e) and fixed on a head (m) of an internal combustion engine installed in an engine compartment of a motor vehicle.