A novel real-world braking cycle for studying brake wear particle emissions

Until now, a wide range of braking conditions has been applied in non-exhaust emissions related studies. This often led to incomparable results and contradictory conclusions. Furthermore, there is no industry-wide accepted brake cycle available that represents real-world braking conditions. In this study a novel braking cycle is presented aiming towards a commonly accepted methodology for sampling and measuring brake wear particles. The cycle is based on the WLTP reference database, which includes in-use driving data from five different world regions with a total mileage of 740,000 km. The cycle development and statistical match to the WLTP database is presented. Experimental testing of the cycle both on the brake dynamometer and vehicle level are shown. Brake disc temperature behaviour on the real vehicle and dynamometer level is compared. It is shown that below a disc temperature of 160 degrees C, particle number emission is at background and sharply increases at brake temperatures above.