A pre-cleaner for an internal combustion engine is arranged in an intake passage of the internal combustion engine at an upstream side of a filter of an air cleaner. The pre-cleaner includes a casing that includes a cylindrical side wall and swirl generation vanes that swirl intake air about an axis of the casing. The side wall has a portion located next to an upstream side of the swirl generation vanes that is formed from an air-permeable fibrous molded body.

An intake duct for an internal combustion engine includes a plurality of segments coupled together into a tubular shape. The segments include at least a first segment and a second segment. The first segment is formed from a material harder than the second segment. The first segment includes a groove that extends in the extending direction in a portion coupled to the second segment and projections that project from one of two inner surfaces of the groove. The second segment is formed from a material that allows for elastic deformation. The second segment includes a rib. The rib extends in the extending direction and has a projection width that is less than the opening width of the groove. The rib is fitted into the groove so that the projections locally compress the rib in the width direction of the groove.

An inlet duct for an internal combustion engine includes a tubular body portion having an air-permeable side wall and a tubular suction portion that is arranged on an upstream side of the body portion in an intake airflow direction and has an inner peripheral surface that expands radially outward toward the upstream side. The body portion and the suction portion are formed integrally by a compression-molded fiber molding.

A high frequency attenuating device for an air flow induction system of a vehicle employing a thermoformed fibrous mat of any shape that fits robustly inside the duct. The dissipative nature of the fibrous mat helps in achieving broadband attenuation in the high frequency regime. The ability to manufacture the fibrous mat into any shape helps with restriction, targets different attenuation bands, and makes it more feasible to manufacture. Hybrid solutions are possible when combined with low frequency perforated silencers or high frequency QWT arrays injection molded onto them.

A method for manufacturing a waterproof felt duct may include (a) laminating a waterproof film on one side of a first nonwoven fabric and laminating a second nonwoven fabric on the waterproof film laminated on the first nonwoven fabric to form a laminated body; (b) forming a waterproof felt base material by thermally adhering the laminated body; (c) cutting the waterproof felt base material into a desired shape; (d) molding a duct while surrounding the waterproof felt base material cut into the desired shape around the external surface of a molding jig having a worm gear shape; (e) heat-treating the molded duct; (f) cooling the heat-treated duct; and (g) ejecting the cooled duct from the molding jig.

A composite resonator, such as for use in a vehicle air intake system, includes a fiber reinforced contacting a semi-crystalline polymer substrate. The fiber reinforced composite includes a plurality of fibers in a polymer matrix. The composite resonator further includes a particle coating contacting the fiber reinforced composite. The particle coating includes a plurality of particles deposited onto the fiber reinforced composite. In a vehicle air intake system, the composite resonator is connected to the air intake pathway. The vehicle air intake system also includes a turbocharger compressor connected to the air intake pathway.

An intake duct for an internal combustion engine includes a tubular side wall. The side wall includes a first molded body and a second molded body that are separate from each other in a circumferential direction of the side wall. The first molded body includes first and second joints. The second molded body includes first and second joints. The first and second joints of the first molded body and the first and second joints of the second molded body are joined to each other. The first molded body includes a rib protruding toward the second molded body and extending in an axial direction of the side wall. The rib is located inward from the first and second joints of the first molded body. The second molded body includes an accommodation recess that accommodates the rib. The accommodation recess is located outward from the rib.

An air cleaner includes a housing and a filter element located within the housing. The housing includes a housing body and a fiber molding assembly. The housing body is formed by a plastic molding. The housing body has a wall located upstream of the filter element in an air flow direction and a recess, which is an inwardly recessed part of the wall. The fiber molding assembly is fixed to the wall, covers the recess from outside, and forms a part of a side wall of an inlet passage together with the recess. A communication hole for communication between the inlet passage and an interior of the housing body is formed in the recess.

A tunable, noise-attenuating resistive silencer assembly for use with an internal combustion engine is disclosed. The resistive silencer assembly incorporates a resistive silencer material. The assembly includes an intake duct having air inlet and outlet ends, an acoustic absorbing material support structure positioned between the air inlet and air outlet ends, and an acoustic absorbing element supported by the acoustic absorbing material support structure. The acoustic absorbing element has a defined and non-amorphous shape. The air enters the air inlet end, passes by the acoustic absorbing material, and exits the air outlet end. The acoustic absorbing element is formed from a foam material that may be open cell or closed cell. If open cell foam, the material may be either a low density or high density polyurethane foam. If closed cell foam, the material may be crushed, closed-celled ethylene propylene dieme or polyvinyl nitrile foam.

An acoustic damper includes a housing with an inlet aperture and an outlet aperture. The housing is configured to receive a gas flow that enters via the inlet aperture and that exits via the outlet aperture. The acoustic damper also includes a barrier member that is disposed within the housing. The barrier member is configured to be disposed within the gas flow and to dampen acoustic energy that propagates in an upstream direction generally from the outlet aperture toward the inlet aperture. The barrier member includes an outer structure that defines an interior volume of the barrier member. The interior volume is oriented toward the outlet aperture.