An intake noise reduction device that can mitigate deformation of a flow-regulating net portion made of an elastic body. The intake noise reduction device 100 is made of an elastic body that is disposed downstream of a throttle valve and includes an annular gasket portion 110 and a flow-regulating net portion 120 provided inside the gasket portion 110 integrally with the gasket portion 110, constituted by a linear portion having a mesh shape. The linear portion having the mesh shape constituting the flow-regulating net portion 120 includes first linear parts 121 that extend radially and second linear parts 122 that extend circumferentially. One of any given two parts of the first linear part 121 on a radially outer side has a width larger than or equal to that of the other part on a radially inner side, and a radially outermost part of the first linear part has a larger width than a radially innermost part.

A variable noise attenuation element is disclosed that comprises a tube, at least one valve seat, at least one valve body and a wire connected to the valve body. The tube has an overall length that defines a first effective length for noise attenuation. The valve seat is disposed in the tube. Retraction of the wire brings the valve body into engagement with the valve seat to selectively define a second effective length of the tube that is less than the overall length.

Intake noise suppression techniques for a forced-induction engine having a low pressure exhaust gas recirculation (LPEGR) system configured to recirculate exhaust gas produced by the engine to an intake system of the engine via an EGR port comprise receiving, from a mass air flow (MAF) sensor of the engine, a MAF signal indicative of measured airflow through the intake system, detecting, based on the MAF signal, intake system conditions that are indicative of audible noise, and in response to detecting the detected intake system conditions that are indicative of audible noise, at least partially closing a differential pressure (dP) valve to mitigate or eliminate the intake system conditions and the corresponding audible noise, wherein the MAF sensor is disposed in the intake system upstream from the dP valve.

An air intake device with a variable-length intake duct, comprising: a base duct component with a base duct, configured for the passage of intake air through the base duct component, an extension duct component with an extension duct, configured for the passage of intake air through the extension duct component, a guidance arrangement which guides the extension duct component and the base duct component to relative movement between a first operating position and a second operating position, wherein in the first operating position the base duct and the extension duct form, in mutually prolonging abutment, a continuous duct section, and wherein in the second operating position the extension duct is arranged at a distance from the base duct, and a first centering arrangement which when the duct components approach the first operating position is configured to decrease a radial distance in relation to a virtual base duct path conceived as passing centrally through the base duct between an end section of the base duct facing towards the extension duct component and an end section of the extension duct facing towards the base duct component, wherein the first centering arrangement is configured as separate from the base duct and from the extension duct.

An air cleaner assembly can contain an air filter element to filter contaminant material out of an air stream. In some examples, the air cleaner assembly includes a housing with an integrated noise suppression chamber for supplying air to a downstream compressor. The housing forms a cavity into which an air filter element is inserted. Contaminated air enters the housing and passes through the air filter. Filtered air can discharge from the housing through a first opening supplying air to a combustion engine and a second opening supplying air to a compressor. Air supplied to the compressor passes from the interior of the housing containing the filter element and through the integrated noise suppression chamber before being discharged. The acoustic energy released by the filtered air stream exiting the air cleaner assembly may be reduced by passing through the noise suppression chamber.

A negative pressure control valve (44) is disposed in a part of an intake passage (12) upstream of a confluence (30) of an EGR passage (27) and the intake passage (12). When in an EGR region (Regr) where an EGR gas is recirculated to the intake passage (12) through the EGR passage (27), the negative pressure control valve (44) is controlled in a manner to ensure a differential pressure between an exhaust passage (13) and the intake passage (12). When in an operation region (R2) lower in load than the EGR region (Regr), the negative pressure control valve (44) is controlled in a closing direction so as to suppress occurrence of noise.

An air intake device with a variable-length intake duct, comprising: a base duct component with a base duct, configured for the passage of intake air through the base duct component, an extension duct component with an extension duct, configured for the passage of intake air through the extension duct component, a guidance arrangement which guides the extension duct component and the base duct component to relative movement between a first operating position and a second operating position, wherein in the first operating position the base duct and the extension duct form, in mutually prolonging abutment, a continuous duct section, and wherein in the second operating position the extension duct is arranged at a distance from the base duct, and a first centering arrangement which when the duct components approach the first operating position is configured to decrease a radial distance in relation to a virtual base duct path conceived as passing centrally through the base duct between an end section of the base duct facing towards the extension duct component and an end section of the extension duct facing towards the base duct component, wherein the first centering arrangement is configured as separate from the base duct and from the extension duct.

Intake noise suppression techniques for a forced-induction engine having a low pressure exhaust gas recirculation (LPEGR) system configured to recirculate exhaust gas produced by the engine to an intake system of the engine via an EGR port comprise receiving, from a mass air flow (MAF) sensor of the engine, a MAF signal indicative of measured airflow through the intake system, detecting, based on the MAF signal, intake system conditions that are indicative of audible noise, and in response to detecting the detected intake system conditions that are indicative of audible noise, at least partially closing a differential pressure (dP) valve to mitigate or eliminate the intake system conditions and the corresponding audible noise, wherein the MAF sensor is disposed in the intake system upstream from the dP valve.

A cold air intake system is provided for actively controlling airflow based upon user input and/or demand conditions. Two air inlets are provided into a sealed air box with the secondary air intake including an air control valve for modulating intrusion of intake air. The valve has a valve seat formed the housing sidewall and a flap door valve member actively actuated via a controller. The mass air flow sensor indicates total demand. A pressure sensor and a temperature sensor provide additional input from the airbox. The controller modifies the valve position based upon pressure, temperature and mass air flow. Control is biased to increase secondary air intake when airbox pressure decreases and biased to decrease secondary air intake when airbox temperature increases. Controller biasing occurs between 30° F. to 160° F. and over pressure ranges between 0.01″ H.sub.2O to 5″ H.sub.2O.

An air cleaner assembly can contain an air filter element to filter contaminant material out of an air stream. In some examples, the air cleaner assembly includes a housing with an integrated noise suppression chamber for supplying air to a downstream compressor. The housing forms a cavity into which an air filter element is inserted. Contaminated air enters the housing and passes through the air filter. Filtered air can discharge from the housing through a first opening supplying air to a combustion engine and a second opening supplying air to a compressor. Air supplied to the compressor passes from the interior of the housing containing the filter element and through the integrated noise suppression chamber before being discharged. The acoustic energy released by the filtered air stream exiting the air cleaner assembly may be reduced by passing through the noise suppression chamber.