A silencer, for example an intake silencer for an internal combustion engine, may include a pipe for conducting a gas mixture. The pipe may be perforated at least in some regions. An absorption layer may at least partially surround the pipe for absorbing a sound transmitted by the gas mixture. An outer casing may encase the pipe. The outer casing may be perforated at least in some regions and may surround the absorption layer.

A resonator (12) for reducing intake air noise is connected to an intake air duct (6) connecting a throttle chamber (5) and an air cleaner case (7). This blow-by gas treatment device is equipped with a fresh air introduction passage comprising a fresh air introduction hose (16), and a blow-by gas passage comprising a blow-by gas hose (20), with the fresh air introduction hose (16) connecting a cylinder head cover (4) and the resonator (12). A connector part (15) of the resonator (12) to which the fresh air introduction hose (16) is connected is provided with an orifice (21) formed integral with a lower body (13) formed of a synthetic resin, as a part thereof. Pulsation is effectively reduced by the throttling effect of the orifice (21) and the expansion effect of the resonator (12).

A method including providing a mold cavity to produce an outer contour of an acoustic resonator and providing a mold core to produce an inner contour of the resonator. The inner contour corresponds to a plenum, and a connecting channel in fluid communication with the plenum. An insert fitting adjacent to the mold core defines a length of the connecting channel during injection molding of the resonator.

A vehicle resonator according to the present invention comprises: an exterior part having an internal space provided therein; an inner pipe part inserted into the internal space and having a hollow part formed penetrating the center; and a resonance part formed between the inner surface of the exterior part and the outer surface of the inner pipe part.

A device for affecting noise, vibration, and harshness (NVH), for instance, reducing the NVH. The device includes a pouch, which further includes a magneto-rheological material. The pouch has a resonance frequency of vibration. The device further includes one or more coils associated with the pouch. The device is configured to activate the one or more coils associated with the pouch, which causes a property of the magneto-rheological material of the pouch to change and thereby shifts the resonance frequency of the pouch.