Moving towards more environmental-friendly brake systems requires the mass and number reduction of their emissions. Moreover, limiting the emissions eco-toxicological behaviour is an additional strategy to reduce their environmental impact. This can be reached by increasing the overall dimensions of the emitted particulates as well as by suitably tailoring their chemical composition. As far as the latter point is concerned, sound understanding of both the chemical modifications occurring at the tribological interface and the emissions chemical composition is needed. Furthermore, to achieve reliable eco-toxicological assessments of specific braking pairs, the reproducibility of the chemical composition of their emissions has to be verified as stable and constant at least over the time and the testing sites. Therefore, this work proposes a first example of inter-laboratory assessment of the chemical composition of emissions generated by brakes. More in detail, the same friction couple composed by a standard grey cast-iron braking disc and a standard copper-free ECE R90 friction material is tested at the dynamometric bench in two different testing laboratories over the same braking cycle (WLTP). The generated PM10 emissions are then collected by the mean of suitable sampling lines and analyzed for both their elemental and phase composition, respectively by the mean of Energy Dispersive Spectroscopy (SEM-EDS) and X-Ray Diffraction (XRD). Finally, the emissions compositional results are compared to evaluate their variability level. Notably, the results shown in the contribution represent a first example of inter-laboratory assessment of the chemical composition of the emissions generated by brakes, thus widening the field of standardization also to the chemistry of such emissions.

Brembo S.p.A: Dr. Alessandro Mancini, Ms. Bozhena Tsyupa, Dr. Matteo Federici, Dr. Andrea Bonfati; ITT Friction Technology: Dr. Simone Analoni, Dr. Agusti Sin