Transfer Function Techniques for Automotive Interior Noise Due to the Induction System


Cuschieri, Joseph M. and Glegg, Stewart A. L. and Yeager, David M.


Prediction of the contribution of induction system noise to driver's ear noise in passenger cars and trucks is approached using acoustic transfer functions. Two transfer functions are defined. The induction system transfer function relates the aeroacoustic source at the intake valve to the acoustic pressure at the snorkel inlet. The car body transfer function relates the snorkel acoustic pressure to driver's ear noise. These transfer functions are cascaded to produce a transfer function from the valve to driver's ear acoustic pressure. The induction system transfer function can be obtained by efficient and relatively accurate mathematical models. The car body transfer function is obtained in full throttle acceleration road tests in which the production induction system is replaced by a simple pipe in order to create high acoustic levels at the driver's ear attributable to the induction system. Sound pressure level measurements are made at the snorkel and at the driver's ear and are post processed using an order tracking algorithm to produce an experimental transfer function in one-third octaves. The usefulness of this approach is substantiated by use of the measured car body transfer function for a light truck with measured snorkel noise produced by a production induction system. Predicted driver's ear noise is found to correlate well with measurements.

Meeting Name

Proceedings - National Conference on Noise Control Engineering (1994, Fort Lauderdale, FL, USA)


Mechanical and Aerospace Engineering

Document Type

Article - Conference proceedings

Document Version


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© 1994 Institute of Noise Control Engineering, All rights reserved.

Publication Date

01 Jan 1994

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