Exhaust noise reduction device

Abstract

Abstract PURPOSE:To remarkably reduce an exhaust noise level through a simple construction, by offsetting a noise from the outlet of exhaust tube with the sound from a speaker having a reverse phase and the same amplitude. CONSTITUTION:An acoustic tube 10 is provided adjacent to the outlet 3a of exhaust tube 3 placed in position below the floor panel 4 of vehicle body for covering the exhaust tube 3 to present a double tubular structure. The sonic tube 10 is connected via a heat resistant rubber bellows 11 with a speaker 12. The speaker 12 is placed in position above the opening 4a of floor panel 4 and provided at its circumference with a speaker casing 15 having a sound absorbing material 14 coated around the inner periphery thereof. The energization of speaker 12 is preset by means of a control circuit 16 so that the sound of speaker 12 may have a reverse phase and the same amplitude relative to a noise from the outlet 3a of exhaust tube 3. The exhaust frequency noise is thus cancelled, and thereby eliminating the exhaust noise.

Inventors

• 👤 Toshiyuki Kaminaga
• 👤 神長　俊之

Bibliographic Details