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Patent Searching and Data

Document Type and Number:
Japanese Patent JP2002521601
Kind Code:
The invention relates to a device and a method for actively reducing the noise emissions of internal combustion engines (1) in an exhaust pipe (2) which guides a stream of exhaust gas (3). To this end, the device has at least one first electroacoustic transducer (3) for converting the sound waves (30) into first signals (31) which are a measure of the frequency, amplitude and phase of the sound waves (30). An electronic control unit (14) converts the first signals (31) into second signals (32). At least one second electroacoustic transducer (15), which is situated centrally in the stream of exhaust gas (3), converts the second signals (32) into compensating sound waves (33) which have a frequency, amplitude and phase so that the sound waves (30) and the compensating sound waves (33) at least partially cancel each other out. The device can also be used for diagnosing the status or functioning of the internal combustion engine and to this end, has a comparison unit (23) in which the first signals (31) of the first electroacoustic transducer (13) are compared with specified signals.

Nagel, friedtomund
Application Number:
Publication Date:
July 16, 2002
Filing Date:
July 22, 1999
Export Citation:
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Nagel, friedtomund
International Classes:
F01N1/00; F01N1/06; F01N3/20; F01N3/28; F02C7/045; G10K11/178; (IPC1-7): F01N1/00; F01N1/06; F01N3/20; F01N3/28
Attorney, Agent or Firm:
Masutoshi Hosoda (2 outside)