Abstract
Nowadays, one of the main pillars of research and development inside the automotive industry is the way to reduce the CO2 emissions that the vehicle produce when running with the final target of protect the environment. So, the Rolling Resistance assessment and research are two basic issues for the OEM’s and the tyre manufacturers.
According to the EC Regulation 661/2009, which establishes requirements for the typeapproval of newly-manufactured tyres with regard to their safety, rolling resistance performance and rolling noise emissions, the EC Regulation 1222/2009 indicates the labelling steps, more restrictive than the ones appearing in the ECE Regulation nº117, dividing the tyres type for vehicles and the limit of the RR coefficient. So, national authorities shall refuse to grant new types of tyre which do not comply with this Regulation from 1 November 2012, and shall forbid the sale of new tyres for new vehicle of categories M, N and O in 1 November 2016 in the first step of values.
Due to this labelling, a high precision RR coefficient measure is needed. As shown in the ISO 28580, four different test methods can be used in order to determinate the Rolling Resistance of a tyre. Those methods are force, torque, power and deceleration.
One of the main issues nowadays being developed is the definition of the European Reference, comparing Rolling resistance test results from different tyres in different machines. Those machines must have a high repeatability of results and a maximum acceptable value of maximum of 0.05 as standard deviation.
This paper describes the development process of this new tyre reference machine inside the field of Rolling Resistance, with the possibility of doing homologation and labelling tests with the four possible methods, which makes that IDIADA type approval agency gives a complete service to the tyres manufacturers.
Applus+ IDIADA and the Applus+ Chair of the Technical University of Catalonia, taking advantage of this new machine, are doing together research activities to achieve a deeper knowledge of the rolling resistance. First results obtained show that an interval exists where the rolling resistance coefficient experiments a local minimum value and at lower and higher speed the rolling resistance increases its value. So, if we are talking about the fuel consumption, an interval of speeds exist where the fuel consumption related to the rolling resistance is minimum and a point of maximum efficiency.
Keywords: Rolling resistance, tyres homologation, regulation