A snap-action valve assembly for an exhaust system is provided with a conduit that defines an exhaust passageway. A valve flap is disposed within the exhaust passageway for controlling exhaust flow. A shaft supports the valve flap in the exhaust passageway and allows the valve flap to rotate between closed and open positions. A mass damper, positioned outside the conduit, includes a longitudinal segment that is rotatably coupled to the shaft and that extends between first and second coiled ends. The longitudinal segment includes an inboard side and an outboard side. The first and second coiled ends include a series of overlapping layers arranged in either a folded serpentine shape or a spiral shape.

A sound generation assembly unit, for an exhaust system of an internal combustion engine, includes a sound generation module (16) with a sound generation module housing to be arranged at an exhaust gas guide element (12) of the exhaust system (14). At least one loudspeaker unit (20) is arranged in the sound generation module housing (18). A rear volume module (30) includes a rear volume module housing (32) and a rear volume (34) formed in the rear volume module housing (32). The rear volume module housing (32) is connected or can be connected to the sound generation module housing (18) for the acoustic coupling of the rear volume (34) to the at least one loudspeaker unit (20).

A device for controlling an exhaust sound of a vehicle includes a sound tunnel mounted near a muffler and an exhaust pipe so as to transmit exhaust sound to an interior of a vehicle, a sound introduction hole formed in the sound tunnel, and a catalytic assembly mounted in the sound tunnel so as to clog the sound introduction hole, the catalytic assembly functioning to reduce high-frequency noise and to filter exhaust gas, thereby reducing high-frequency noise included in the exhaust sound transmitted to the interior of the vehicle and thereby filtering the exhaust gas so as to prevent introduction of the exhaust gas into the interior of the vehicle.

A vehicle exhaust component includes a body with an open inner cavity providing a fixed volume and a neck having one end associated with the fixed volume and an opposite end associated with an exhaust gas flow path. A flexible membrane separates the fixed volume into a first chamber and a second chamber. An actuator is used to vary a tension of the flexible membrane.

A snap-action valve assembly for an exhaust system is provided with a conduit that defines an exhaust passageway. A valve flap is disposed within the exhaust passageway for controlling exhaust flow. A shaft supports the valve flap in the exhaust passageway and allows the valve flap to rotate between closed and open positions. A mass damper, positioned outside the conduit, includes a longitudinal segment that is rotatably coupled to the shaft and that extends between first and second coiled ends. The longitudinal segment includes an inboard side and an outboard side. The first and second coiled ends include a series of overlapping layers arranged in either a folded serpentine shape or a spiral shape.

An exhaust gas system for an internal combustion engine includes a first exhaust gas line leading into a first muffler; a second exhaust gas line arranged fluidly parallel to the first exhaust gas line and leading into a second muffler, wherein the first and second exhaust gas lines are respectively connected upstream of the first and second muffler at a branch to a common exhaust gas feed line; a control valve arranged in the first exhaust gas line upstream of the first muffler; and a damping device fluidly arranged between the branch and the control valve and adapted for damping exhaust gas resonance vibrations.

An exhaust-gas aftertreatment device (10) for an internal combustion engine, particularly for a marine diesel internal combustion engine operated using heavy fuel oil, includes a housing (11); an exhaust-gas chamber (12) defined by the housing (11), for permitting exhaust gas to flow continuously through the housing (11), an inlet (13) for permitting exhaust gas to flow into the housing and an outlet (14) for permitting exhaust gas to flow out of the housing (11); a sound damping chamber (15), defined by the housing (11) and coupled with the exhaust-gas chamber (12). The sound dampening chamber (15) is constructed to receive a fluid or a pourable solid at a fill level depending on the frequency of an exhaust sound to be damped.

A noise suppression apparatus and a fan module using the same are provided. The noise suppression apparatus includes a resonator, a status indication unit, and a first thermoelectric component. The resonator is disposed on a sound transmission tube of a noise generation source, and includes a chamber and a clapboard disposed in the chamber. The status indication unit generates a control signal according to an operational status of the noise generation source. The first thermoelectric component is disposed in the resonator, and has a first terminal fixed on a sidewall of the chamber and a second terminal connected to the clapboard. The first thermoelectric component deforms in response to the control signal as the operational status of the noise generation source changes, so as to move the clapboard to change resonance volume of the resonator, and thus resonance frequency of the resonator approaches noise frequency of the noise generation source.

A slip-type active noise control muffler reducing exhaust noise of a vehicle may include at least two guides connected to an inner wall of a housing accommodating exhaust gas in the muffler and formed in a pipe shape in a longitudinal direction of the muffler, and a baffle positioned in a plane shape partitioning the interior of the housing and including an electromagnet on the plane shape to control an interval of the baffles through a movement signal by current applied to the electromagnet according to frequency calculated from the exhaust gas, in which the interval of the baffles may be controlled and the exhaust noise may be reduced by controlling the number of wavelengths depending on the frequency.

The gas turbine engine includes a fluid system fluidly connecting at least two components of the gas turbine engine, and a tunable resonator in fluid flow communication with the fluid system. The tunable resonator has a resonating volume that varies as a function of a volume of an inflatable member located inside the tunable resonator. The inflatable member having a means for varying the volume of the inflatable member, to thereby tune the resonating volume to a selected frequency of pressure fluctuations or acoustic waves within the fluid system.