Engine exhaust noise silencer - has casing with cells temporarily storing gas under pressure released when pressure falls

摘要

The silencer reduces the exhaust noise from an internal-combustion engine, the gases under pressure being temporarily stored, and released when pressures subsequently fall. Thus pressure is regularised at the core of an acoustic attenuator, the latter operating particularly by reflection, absorption, interference and/or resonance. The silencer used for this system can have a casing containing a large number of interconnected acoustic attenuation sections. These each consist of a chamber incorporating a perforated tube between inlet and outlet. There is also a dead-ended pressure regulation chamber (C4) with no tube, forming a temporary reservoir for gas under pressure, and connected to the casing between two of the sections.