Abstract
Brake particle emissions (BPE) have become more and more relevant during the discussions of non-exhaust emissions of road vehicles. Since this topic is still quite young, only poor experiences exist in terms of different friction couples and the impact of various test cycles. After introducing a reliable measurement setup which considers a brake dynamometer, a comparison of the peculiarities of two different low steel brake lining materials in combination with a standard grey cast iron disc is shown. This presentation includes beside the typical tribological parameters (like coefficient of friction, wear and temperature behaviour) also the particle emission behaviour which is characterized by particle number concentration and particle size distributions. Another issue of the presented paper deals with a copper-free NAO lining material, again combined with a standard cast iron disc. It is shown, that the brake load determines the particle emissions in a crucial way. A direct comparison to a standard low steel material is given additionally. Last but not least the particle emission and tribological behaviour of a hard-metal coated brake disc is investigated. For that reason a brake pad with a formulation optimized for carbon-ceramic brakes is used. Since it was observed that the brake load plays a crucial role for BPE, the above mentioned friction couples were characterized by using different dynamometer test cycles, namely the New European Driving Cycle (NEDC) and a modified AK Master. It can be concluded that friction couples can be optimized for certain operating parameters, but beyond those loads the particle emission can increase significantly.
KEYWORDS Brake particle emissions, Particle number concentration, Hard-metal coated brake disc, Friction behaviour