Title: Noise attenuation of the engine compartment of a vehicle

Authors: David Ibarra

Addresses: Tecnológico de Monterrey, Escuela de Ingeniería y Ciencias, Calle del Puente 222, Ejidos de Huipulco, Tlalpan, 14380, Mexico City, Mexico

Abstract: Road traffic noise amounts to roughly half of the overall ambient noise. Usual noise control techniques have not been enough to decrease the noise annoyance by road traffic along the last decades. In order to relate the noise levels generated by the vehicle at near field with the usual levels radiated to the far field, it is necessary to characterise the noise reduction produced by the engine hood. Here, preliminary results on such characterisation are presented. Insertion loss and transmission loss have been measured in several locations around the vehicle. Besides the microphone inside the engine compartment, another microphone is needed outside the vehicle. The responses between a loudspeaker and both microphones were measured using the maximum length sequence method. Preliminary results show that noise reduction provided by the engine hood depends on the microphone location, varying from 16 dB to 27 dB at vertical and lateral positions.

Keywords: engine noise; vehicle noise; engine compartment; transmission loss; insertion loss.

DOI: 10.1504/IJVNV.2017.086029

International Journal of Vehicle Noise and Vibration, 2017 Vol.13 No.1, pp.66 - 72

Received: 20 Aug 2016
Accepted: 23 Jan 2017

Published online: 08 Aug 2017 *

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