Abstract: A method for attenuating the low-frequency noise generated at the outlet (18) of an exhaust line (14). A signal representing the noise to be attenuated is defined; a first high-frequency acoustic wave (F1) is emitted from a first transducer (22) into an attenuation region (26) of the exhaust line (14), the first acoustic wave having a carrier frequency higher than 50 kHz; and a second high-frequency acoustic wave (F1+?fcb) is emitted by a second transducer (24) into the attenuation region (26) of the exhaust line, the second acoustic wave having the carrier frequency of the first high-frequency acoustic wave (F1) and containing a low-frequency counter-noise signal (?fcb) which is out of phase with the signal representing the noise to be attenuated.

Abstract: A method for attenuating the low-frequency noise generated at the outlet (18) of an exhaust line (14). A signal representing the noise to be attenuated is defined; a first high-frequency acoustic wave (F1) is emitted from a first transducer (22) into an attenuation region (26) of the exhaust line (14), the first acoustic wave having a carrier frequency higher than 50 kHz; and a second high-frequency acoustic wave (F1+?fcb) is emitted by a second transducer (24) into the attenuation region (26) of the exhaust line, the second acoustic wave having the carrier frequency of the first high-frequency acoustic wave (F1) and containing a low-frequency counter-noise signal (?fcb) which is out of phase with the signal representing the noise to be attenuated.

Abstract: The invention relates to a method and device for avoiding the deposition of particles of soot (3) on the insulating components (2) in an electrostatic filter (1), which comprises the insulating components (2). The method comprises the method step of creating a repulsive electrostatic field (4) around said insulating components (2), by placing at least one repulsive electrode (8) in or on at least one of the insulating components (2) and applying an adequate voltage to the repulsive electrode (8). The voltage difference between the repulsive electrode (8) and the central electrode (6) and the voltage difference between the repulsive electrode (8) and the peripheral electrode (7) creates an electrical repulsive field (4), which repulses the particles of soot having an electrical charge. The formation of a conducting channel (5) on the surface of said insulating components (2) between the central electrode (6) and the peripheral electrode (7) can thus be avoided.