Abstract: A variable noise attenuation element includes at least two tube sections that define an overall tube length that defines a first effective length and associated first peak frequency for noise attenuation, and a valve having a valve member. The valve joins the tube sections together and includes openings that permit communication between the tube sections when the valve is in an open configuration. The valve member operates to close the opening in response to a predetermined vacuum level within the tube sections to define a second tube effective length and associated second peak frequency for attenuation that is less than the overall length. A method of attenuating noise in a vehicle using a passive attenuation arrangement operates a valve disposed between two tube sections to change an effective length of the tube and associated peak frequencies for attenuation in response to an engine operating parameter.

Abstract: A variable noise attenuation element includes at least two tube sections that define an overall tube length that defines a first effective length and associated first peak frequency for noise attenuation, and a valve having a valve member. The valve joins the tube sections together and includes openings that permit communication between the tube sections when the valve is in an open configuration. The valve member operates to close the opening in response to a predetermined vacuum level within the tube sections to define a second tube effective length and associated second peak frequency for attenuation that is less than the overall length. A method of attenuating noise in a vehicle using a passive attenuation arrangement operates a valve disposed between two tube sections to change an effective length of the tube and associated peak frequencies for attenuation in response to an engine operating parameter.

Abstract: A variable noise attenuation element includes at least two tube sections that define an overall tube length that defines a first effective length and associated first peak frequency for noise attenuation, and a valve having a valve member. The valve joins the tube sections together and includes openings that permit communication between the tube sections when the valve is in an open configuration. The valve member operates to close the opening in response to a predetermined vacuum level within the tube sections to define a second tube effective length and associated second peak frequency for attenuation that is less than the overall length. A method of attenuating noise in a vehicle using a passive attenuation arrangement operates a valve disposed between two tube sections to change an effective length of the tube and associated peak frequencies for attenuation in response to an engine operating parameter.

Abstract: A variable noise attenuation element includes at least two tube sections that define an overall tube length that defines a first effective length and associated first peak frequency for noise attenuation, and a valve having a valve member. The valve joins the tube sections together and includes openings that permit communication between the tube sections when the valve is in an open configuration. The valve member operates to close the opening in response to a predetermined vacuum level within the tube sections to define a second tube effective length and associated second peak frequency for attenuation that is less than the overall length. A method of attenuating noise in a vehicle using a passive attenuation arrangement operates a valve disposed between two tube sections to change an effective length of the tube and associated peak frequencies for attenuation in response to an engine operating parameter.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A tunable, sound enhancing air induction system for an internal combustion engine includes an air supply duct extending between an air cleaner and a throttle body, and an acoustic amplifier mounted to the air supply duct at an anti-node of a desirable engine induction sound. The acoustic amplifier furnishes the desired sound to the passenger compartment of the vehicle, either through a duct, or by a directional horn.

Abstract: An air induction sound modification system for an internal combustion engine includes a multi-frequency sound suppression unit having Helmholtz resonators and a multi-component expansion chamber. A sound generator, which functions to radiate sound at a desirable, tuned frequency, extends between the multi-function sound suppression unit and a second expansion chamber, such as an air cleaner box.

Abstract: A tunable, sound enhancing air induction system for an internal combustion engine includes an air supply duct extending between an air cleaner and a throttle body, and an acoustic amplifier mounted to the air supply duct at an anti-node of a desirable engine induction sound. The acoustic amplifier furnishes the desired sound to the passenger compartment of the vehicle, either through a duct, or by a directional horn.

Abstract: An air induction sound modification system for an internal combustion engine includes a multi-frequency sound suppression unit having Helmholtz resonators and a multi-component expansion chamber. A sound generator, which functions to radiate sound at a desirable, tuned frequency, extends between the multi-function sound suppression unit and a second expansion chamber, such as an air cleaner box.