An air induction system includes an air duct and an air permeable membrane. The air duct is configured to deliver intake air to an engine. The air duct includes a cylindrical wall defining a bore and an enclosure projecting from an outer radial surface of the cylindrical wall and defining a cavity therein. The cylindrical wall has an opening extending therethrough that enables airflow from the bore to the cavity in the enclosure. The air permeable membrane is configured to cover the opening in the cylindrical wall.

An air intake duct includes a peripheral wall, which is formed by a compressed fiber portion made of a compression molded fiber material. The compressed fiber portion includes high-compression portions having a high compression ratio and low-compression portions having a relatively low compression ratio. The high-compression portions include circumferentially extending sections. Each circumferentially extending section is located in a plane that is perpendicular to an extension direction of the peripheral wall with part of the circumferentially extending section disposed between the low-compression portions. Each circumferentially extending section extends continuously over the entire circumference of the peripheral wall.

A duct includes a circumferential wall. At least part of the circumferential wall is a fibrous portion that includes fibers. The fibrous portion includes a breathable inner layer located on an inner circumferential side in the circumferential wall and an outer layer located on an outer circumferential side of the inner layer in the circumferential wall. The outer layer is less breathable than the inner layer. A boundary between the inner layer and the outer layer is breathable.

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.

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 air intake duct includes a peripheral wall, which is formed by a compressed fiber portion made of a compression molded fiber material. The compressed fiber portion includes high-compression portions having a high compression ratio and low-compression portions having a relatively low compression ratio. The high-compression portions include circumferentially extending sections. Each circumferentially extending section is located in a plane that is perpendicular to an extension direction of the peripheral wall with part of the circumferentially extending section disposed between the low-compression portions. Each circumferentially extending section extends continuously over the entire circumference of the peripheral wall.

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.

Methods and systems are provided for a foam sleeve circumferentially surrounding an engine passage. In one example, a system may include a collapsible foam sleeve including cuts on its surface that may be fit onto the engine passage. The foam sleeve may be stacked and transported in a collapsed state and then expanded prior to the fitting to the engine passage.

The present disclosure relates to a pipeline for supplying a gas to an internal combustion engine, with a pipeline cross section forming a passage for the gas and a gas mass measuring device for measuring a gas mass flow. The pipeline is characterized in particular in that it comprises a mixing element made from a wire structure upstream from the gas mass measuring device and in that the mixing element serves for the thorough mixing of the gas in order to homogenize an inhomogeneous flow profile which is present upstream from the mixing element.

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.