An important contribute to terrestrial vehicles noise emission is due to the rolling phenomena of tyres on the pavement. Such a contribute is particularly strong into 50-150 Km/h vehicle speed range. An ANC system for rolling noise attenuation has been already proposed; furthermore an experimental facility has been built at Perugia University Acoustics Lab. in order to test the ANC system on steady (not travelling) condition. The ANC system is made up by two original acoustical emitters (front and posterior emitter) which are to be installed on a vehicle mudguard: the front emitter (posterior emitter) serves to attenuate acoustical emission due to air compression (rarefaction) which occurs when the tyre superposes (gives up) the pavement. Two control units whose input data are tyre r.p.s and an error signal drive the emitters. This paper reports the proposed ANC system performances which have been found by means of the mentioned experimental facilities. The experimental facility allowed to carry out power measurement of rolling noise emission; thus power levels and emission diagram were found both when ANC system is OFF and when is ON. Results show that the proposed ANC system produces robust attenuation of rolling noise into 200-500 Hz frequency range.
Tyre-pavement Noise Active Control System: A Laboratory Prototype Performances
ROSSI, Federico
2000
Abstract
An important contribute to terrestrial vehicles noise emission is due to the rolling phenomena of tyres on the pavement. Such a contribute is particularly strong into 50-150 Km/h vehicle speed range. An ANC system for rolling noise attenuation has been already proposed; furthermore an experimental facility has been built at Perugia University Acoustics Lab. in order to test the ANC system on steady (not travelling) condition. The ANC system is made up by two original acoustical emitters (front and posterior emitter) which are to be installed on a vehicle mudguard: the front emitter (posterior emitter) serves to attenuate acoustical emission due to air compression (rarefaction) which occurs when the tyre superposes (gives up) the pavement. Two control units whose input data are tyre r.p.s and an error signal drive the emitters. This paper reports the proposed ANC system performances which have been found by means of the mentioned experimental facilities. The experimental facility allowed to carry out power measurement of rolling noise emission; thus power levels and emission diagram were found both when ANC system is OFF and when is ON. Results show that the proposed ANC system produces robust attenuation of rolling noise into 200-500 Hz frequency range.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
