Device and method for reducing the noise emissions of internal combustion engines and for diagnosing the same

摘要

The exhaust noise reducer for an internal combustion engine has a microphone (4) for sensing a noise wavelength to produce signals with measures of the amplitude and phase of the noise waves. A loudspeaker (7) transposes a compensating noise onto the existing noise for destructive interference. The loudspeaker is centrally mounted in the gas stream.