Impact of potential and dedicated tyres of electric vehicles on teh tyre-road noise and connection to the EU noise label (paper 283)

With the advent of electric vehicles and their significant lower propulsion noise emission it is possible to assess the tyre-road noise trough cruise-by measurements with an increased accuracy, even at speeds where a combustion engine propulsion system would usually disturb the measurement results. The European project FOREVER (Future OpeRational impacts of Electric Vehicles on European Roads) funded by CEDR between 2013 and 2014, aimed to provide data and information on the potential future noise impacts of electric vehicles (EVs) and hybrid electric vehicles (HEVs) on national roads, more specifically (i) the noise levels generated by electric/hybrid vehicles, (ii) how these vehicles can be effectively included in noise prediction models, and (iii) the likely noise impacts for residents as the number of electric/hybrid vehicles on national roads increases. Within work package 3 of the project, concerned with the noise emission of tyres used on EVs and HEVs, nine different sets of tyres have been selected and compared by carrying out pass-by measurements based on the standard ISO 11819-1. Special attention has been paid to potential and dedicated tyre sets which meet the demands for low energy consumption and a low rolling resistance to optimize the range of electric vehicles. The results have been analysed in order to reveal differences between single tyre sets and to quantify the influence of the tyres on the tyre-road noise. In a second part of the work, the EU tyre labels have been considered. The tyre labels have been introduced by the European Community for informing and helping consumers to choose products according to energy efficiency, safety in wet braking conditions and exterior rolling noise. Minimum requirements are also set in type-approval legislation. In the FOREVER project the exterior noise labels of the nine selected tyres have been compared with the results of the pass-by noise measurements performed on a common real-life road surface. Discrepancies observed on tyre ranking between both approaches have been discussed. Investigations within the concept of "low-noise tyres" have been put forward accordingly. Finally, outcomes for the modelling of rolling noise from electric vehicles in the European noise assessment method CNOSSOS-EU, which is recommended for strategic noise mapping in Europe, have been given. As a complement to the EV propulsion noise component previously specified in the FOREVER project, it turns out that no correction term is required for EV rolling noise. In this paper, the main content as well as the outcomes of work package 3 of the project FOREVER are presented.