Integrated Solutions for Noise & Vibration Control in Vehicles

A strong issue on the development of new vehicles is the weight reduction, required for the reduction of the fuel consumption and the CO2 emissions. The current vehicles have already a structure optimised to have low weight without reducing the required performances. However, there are some components of the structure that can be further reduced in weight still matching the resistance, crash and fatigue performances, but giving a poor performance in terms of noise and vibrations and increasing both the structure-borne and air-borne sound transmission.In the European FP7 project Green City Car, flexible, integrated passive and active solutions are developed permitting noise and vibration attenuation in vehicles equipped with the next generation of highly fuel-efficient two- or three cylinder internal combustion engines (ICE). Among others, shunted piezoelectric patches and electro-magnetic actuation as well as smart Helmholtz resonators are considered. Additionally, dedicated active noise control systems for the control of broadband rolling noise are developed. Besides, Green City Car addresses and implements novel damping materials and acoustic treatments as well as design approaches for tyres which are an important acoustic source for exterior and interior noise. This holistic approach should lead to a reduction in noise and vibrations levels in the order of 10 dB(A) and more measurable in the city car provided (not on component level). Currently, Green City Car finished its second year and first results are presented and discussed in this paper.