Induction system with low pass filter for turbo charger applications

This invention relates to a flow tube having a low pass filter positioned in the flow path. Specifically a noise attenuation plate cooperates with ribs formed on internal surfaces of the flow tube to reduce high frequency whistle generated by a turbo charger. A flow tube for an induction system with a turbo charger defines a longitudinal flow path and includes a noise attenuation plate positioned within the flow tube. A plurality of ribs formed on an internal surface of the tube. The ribs are spaced apart from one another and are tuned to a desired frequency. The noise attenuation plate includes a plurality of holes having varying diameter and depths. When acoustic energy created by the turbo charger encounters the noise attenuation plate and the ribs, the change in impedance results in acoustic reflections back toward the turbo charger. Thus the noise attenuation plate cooperates with the ribs to serve as a low pass filter that attenuates high frequencies while allowing lower frequencies through.