An apparatus for reducing flow noise of an air intake system of a vehicle is provided as an assembly of a body member and a cover member. An acoustic metamaterial unit includes a chamber having a predetermined size, an inlet flow path, and an outlet flow path provided therein and is connected to a pipe of an air intake system. The apparatus advantageously reduces or removes high-frequency flow noise occurring in a turbocharger by using the acoustic metamaterial unit. The size and shape of the acoustic metamaterial unit is standardized such that the acoustic metamaterial unit is used compatibly regardless of the type of vehicles, which can make it possible to advantageously reduce costs and improve salability.

A broad-band resonance silencer has an at least two-part housing which is designed to receive an exhaust-or gas-conveying pipe, which defines, with a circumferentially surrounding pipe jacket with acoustic openings formed therein, a pipe interior, wherein the pipe, in its installed position, is enclosed by a damping chamber formed by the housing, which chamber is actively connected to the pipe interior via the acoustic openings, and wherein the housing includes two axially split housing half-shells. In order to broaden the scope of use of such a broad-band resonance silencer, it is proposed that the pipe be designed as an insert which includes a central pipe section with two end-side pipe ends, that the insert be designed such that it can be inserted into the housing half-shells of the housing, and that the broad-band resonance silencer includes at least one acoustic channel.

A resonator includes: an inner pipe having first openings penetrated into an outer peripheral surface thereof from an inner peripheral surface thereof and second openings spaced apart from the first opening; a first cover adapted to allow a first resonant space to be formed between the outer peripheral surface of the inner pipe and the inner peripheral surface thereof, the first resonant space communicating with the internal space of the inner pipe through the first openings; and a second cover adapted to allow a second resonant space to be formed between the outer peripheral surface of the inner pipe and the inner peripheral surface thereof, the second resonant space communicating with the internal space of the inner pipe through the second openings.

A turbocharger includes an acoustic damper for attenuating noise from the compressor. The damper includes inner and outer duct walls defining an annular cavity therebetween, the outer duct being longer than the inner duct. An upstream wall bounds the annular cavity at the upstream end and defines an inlet aperture for fluid to pass through into the inner duct, and a downstream wall is axially spaced from the downstream end of the inner duct so as to define an expansion chamber fluidly connected to the annular cavity. The downstream wall defines an outlet aperture for the fluid. Partition walls between the two ducts partition the annular cavity into at least a first Helmholtz resonator and a first quarter-wave resonator that are axially serially arranged, and a second quarter-wave resonator that is circumferential serially arranged with respect to the first Helmholtz resonator.

A silencer for reducing gas noise in a combustion engine intake system has a tubular casing with a first casing part and a second casing part connected to each other by a weld seam to form an outer casing wall, wherein the weld seam is a part of the outer casing wall. A third part for compensating gas noise is positioned inside the tubular casing. The third part is arranged in the tubular casing such that an annular cavity is formed by the third part and the outer casing wall. A weld flash protrudes from an inner surface of the outer casing wall into the annular cavity and is contained therein. The silencer is produced in a single welding process in which the first and second casing parts are connected to each other to form the outer casing wall and the third part is connected to the tubular casing.

A broad-band resonance silencer has an at least two-part housing which is designed to receive an exhaust-or gas-conveying pipe, which defines, with a circumferentially surrounding pipe jacket with acoustic openings formed therein, a pipe interior, wherein the pipe, in its installed position, is enclosed by a damping chamber formed by the housing, which chamber is actively connected to the pipe interior via the acoustic openings, and wherein the housing includes two axially split housing half-shells. In order to broaden the scope of use of such a broad-band resonance silencer, it is proposed that the pipe be designed as an insert which includes a central pipe section with two end-side pipe ends, that the insert be designed such that it can be inserted into the housing half-shells of the housing, and that the broad-band resonance silencer includes at least one acoustic channel.

A breather device for an outboard motor engine, the outboard motor engine including a breather chamber formed in an engine main body, and an intake passage guiding air into the engine main body, in which an intake port of the intake passage is open inside an engine cover that covers the engine main body, the breather device includes a resonator chamber communicating with an upstream side of the intake passage, and a breather passage extending from the breather chamber and communicating with the resonator chamber.

A straddled vehicle includes an air cleaner and a resonator. The air cleaner includes an air cleaner case, an air-cleaning element arranged inside the air cleaner case, and a duct that is attached to the air-cleaning element. At least a portion of the duct is arranged inside the air cleaner case, and the duct guides the air toward the air-cleaning element. The resonator has an outer wall arranged around the duct. The duct and the outer wall together define at least a portion of a resonance chamber of the resonator.

The invention concerns a device (1) for attenuating intake noise and radiated noise that comprises an internal gas delivery conduit (2) linked to a combustion engine, the conduit (2) having a peripheral wall (23) on at least one portion of which there is disposed at least one element porous to air (4), sound attenuation means comprising at least one tube (3) disposed in the delivery conduit, at least one peripheral chamber (5) being delimited inside the conduit (2) between the tube (3) and the peripheral wall (23) of the conduit (2), the tube (3) comprising at least one portion having an opening (30) allowing the inside of the tube (3) to communicate with the peripheral chamber (5).

A system for reducing noise associated with a compressor of an engine system comprises an intake manifold and a resonator comprising an outlet. The resonator is coupled to, and is positioned adjacent to, the intake manifold. An outlet pipe is in fluid communication with the outlet and the compressor, and a length of the outlet pipe extends from the outlet to the compressor. Positioning the resonator adjacent to the intake manifold reduces the length of the outlet pipe so as to reduce noise associated with air flowing through the outlet pipe.