Lonni, A. and Tanneau, O., "Acoustic Control of Rubber Ducts’ Emissivity," SAE Technical Paper 2016-01-1792, 2016, doi:10.4271/2016-01-1792.
Nowadays, downsizing and turbochargers are more frequently used, mostly for petrol engines. It can lead to an increase of NVH issues related to the turbos, such as the hiss noise propagation in the air ducts. Hutchinson, among all its activities, supplies rubber and plastic parts for the car industry, especially in fluid management systems. The turbocharger’s airborne noise issue has now been tackled for ten years by implementing acoustic devices in the line and providing solutions to car manufacturers with our hot-side rubber ducts. In this paper, will be first presented the main HP air loop NVH issues, and then explained an approach to design technical solutions. Generally speaking, the noise propagates inside the hot side air hoses, crosses the weakest parts of the system by acoustic emissivity to reach finally the driver and passengers’ ears. In order to characterize the hose emissivity under working pressure and temperature conditions, a specific innovative test bench has been developed over the past few years. This tool allows: (i) a better understanding of the material behavior and the radiating properties; (ii) innovative works concerning hoses via material and shape optimization; (iii) a better definition of the targets for silencers and (iv) a more global dimensioning of HP loops aiming at minimizing the impact of the NVH attenuation function on other ones like cost, size, pressure drops or vibration decoupling.