Anti-sound system for exhaust systems and method for controlling the same

摘要

Based on sound measured in the interior of an exhaust system components of an ideal control signal are calculated, the components comprising sine wave oscillations comprising amplitudes phase-shifted by 90° relative to each other. From the amplitudes, an overall amplitude is calculated. If the overall amplitude is greater than a reference amplitude, calculating a correction factor from the reference amplitude and the overall amplitude, weighting the amplitudes with the correction factor to obtain weighted amplitudes, and forming the sum of the products of the weighted amplitudes with the associated sine wave oscillations and outputting the sum as control signal to a loudspeaker, follows. Otherwise, if the overall amplitude is smaller or equal to the reference amplitude, forming the sum of the products of the amplitudes of the ideal control signal with the associated sine wave oscillations and outputting the sum as control signal to the loudspeaker, follows.

主权项

1. A method for controlling an anti-sound system for an exhaust system of a combustion engine-operated vehicle for generating an airborne sound in the exhaust system by means of measured sound, in order to at least partially cancel airborne sound generated by the combustion engine and conducted in the exhaust system in the region of the location in the exhaust system, in which the sound is measured, comprising the following steps:
(S1) measuring sound in the interior of the exhaust system; (S2) calculating components of a first ideal control signal by means of the measured sound, wherein the components comprise two first sine wave oscillations with first amplitudes phase-shifted by 90 degrees relative to each other; (S3) calculating a first overall amplitude from the first amplitudes; (S4) comparing the first overall amplitude with a predetermined reference amplitude in order to determine if the first overall amplitude is greater than the reference amplitude; (S5) calculating a correction factor from the reference amplitude and the first overall amplitude if the first overall amplitude is greater than the reference amplitude; (S6) weighting of the first amplitudes with the correction factor, in order to obtain weighted first amplitudes, if the first overall amplitude is greater than the reference amplitude; and (S7) forming the sum of the products of the weighted first amplitudes with the associated first sine wave oscillations phase-shifted by 90 degrees relative to each other and outputting the sum as control signal on at least one loudspeaker, if the first overall amplitude is greater than the reference amplitude; or (S8) forming the sum of the products of the first amplitudes of the first ideal control signal with the associated first sine wave oscillations phase-shifted by 90 degrees and outputting the sum as control signal to the at least one loudspeaker, if the first overall amplitude is smaller or equal to the reference amplitude.