Title:
NOISE REDUCTION DEVICE
Document Type and Number:
Japanese Patent JPH05195746
Kind Code:
A
Abstract:
PURPOSE:To reduce noise to a great extent with good responsiveness regardless of noise frequencies by absorbing the noise generated in a fluid passage using a Helmholtz resonator with variable resonance frequency. CONSTITUTION:A cavity 4 is connected through a communication pipe 3 to the exhaust passage 1 of internal combustion engine, and a Helmholtz resonator 5 is formed from these pipe 3 and cavity 4. In the pipe 3 a piston 8 with variable resonance frequency is installed which is moved in the axial direction of the pipe 3 by a linear actuator 10. The inner all of the pipe 3 is formed cylindrically, and the outer wall of the piston 8 is embodied in bullet head form so that the resonance frequency of the resonator 5 varies linearly in accordance with the insertion length L of the piston 8, which is inserted in the pipe 3. The insertion length L of the piston 8 is controlled so that the resonance frequency of the resonator 5 is identical to the primary frequency of the exhaust noise generated by combustion in the body of the engine.
Inventors:
OGAWA SUMIO
Application Number:
JP639292A
Publication Date:
August 03, 1993
Filing Date:
January 17, 1992
Export Citation:
Assignee:
TOYOTA MOTOR CORP
International Classes:
F01N1/02; F02M35/12; (IPC1-7): F01N1/02; F02M35/12
Attorney, Agent or Firm:
Aoki Akira (4 outside)
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