Drive Systems: Considerations with Engine Applications - Sound Attenuation
Engine exhaust noise is controlled through the use of silencers and mufflers.
Generally, there is no technical distinction between a silencer and muffler and
the terms are frequently used interchangeably. A silencer has been the traditional
name for noise attenuation devices, while a muffler is a smaller, mass-produced
device to reduce engine exhaust noise.
use of an exhaust silencer is prompted by the need to reduce the engine exhaust
noise. In most applications the final selection of an exhaust silencer is based
on a compromise between the predicted acoustical, aerodynamic and structural performance
in conjunction with the cost of the resulting system.
Despite terms and various configurations, the silencer can be broken
into three fundamental types: reactive, absorptive and combination reactive/absorptive.
In addition to the three main silencer types, other functionality such as spark
arresting, emission control, and heat recovery may also be incorporated into the
silencer design. Each type of silencer has specific performance attributes that
can be used independently or in combination to produce the required insertion
loss (IL) for a specific application.
Sound attenuation enclosures are also available or can be manufactured
for indoor and outdoor installations for most engine driven equipment.
Sound absorbing material is designed to be applied on engine enclosures
or walls and ceilings. Sound stop materials will reduce noise levels by minimizing