Exhaust silencers with minimum power loss

Based on the principle of reflection free duct termination, silencers were -designed. These silencers were applied to reduce the exhaust noise of internal combustion engines.
Acoustical and mechanical measurements have been taken as a function of engine speed for both full and partial load. For comparison, the same measure¬ments have also been carried out on a conventional dissipative silencer of equal length, and also, for purposes of reference, on the exhaust pipe without a si¬lencer.
A high level of acoustic absorption could be realized over a wide frequency range, without changing both the electric power and the fuel consumption of the applied engine, with respect to those for an untreated pipe.