| 摘要 |
<p>PURPOSE: To improve the silencing effect to exhaust sounds by increasing the sound pressure level of the sound waves emitted from a speaker and more particularly the sound pressure level in a low compass. CONSTITUTION: This silencer of an active type includes a branch pipe 2 coupled to an exhaust duct 1 in which exhaust gases flow and the speaker which is disposed on the side of this branch pipe 2 on the side opposite to the side coupled to this exhaust duct 1 and Cod emits the sound waves into the branch pipe 2. The silencer described above silences the exhaust sounds by emitting the sound waves having the magnitude equal to the magnitude of the exhaust sounds of the exhaust gases from the speaker 3 and antiphases. A speaker of a drone cone system having a speaker unit 3b and a drone cone 3c on one side wall of an enclosure 3a is used as the speaker 3. The speaker unit 3b and the drone cone 3c are disposed in the state of exposing both in the hollow part of the branch pipe 2. Then, the sound waves from the speaker unit 3b and drone cone 3c of the speaker 3 are radiated within the hollow part of the branch pipe 2 and eventually the exhaust duct 1.</p> |
