| 摘要 |
The method involves passing the exhaust through the opening of a first valve into a closed chamber. This confines and attenuates the sound wave before the exhaust gas flow reaches the exhaust pipe. The confinement and attenuation are obtained according to the shape of the soundproofing chamber. This shape may be a funnel type ended in a sharpened point or with an elongated bevel to avoid all risk of echo. Alternatively it can be arranged to offer the sound wave two simultaneous propagation paths which meet frontally and mutually neutralise each other. After passing through the chamber the silenced exhaust gas passes through a second valve to into the exhaust pipe.
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