Brake Particles Emissions Characterization During Novel Real-World Driving Cycle

Abstract

This innovative project is addressing the topic, "Brake dust emissions measurement"; specifically, the further investigation of non-exhaust emissions coming from the brake system during the novel WLTP Cycle establish by the PMP Group. Road transport is one of the most important sources of urban pollutant emissions. The upcoming trend of vehicle electrification is enhancing the non-exhaust emissions, with the brake wear particles as the most important part of it. Moreover, the health effects of PM are also proved that it is an important issue to mitigate. Hence, the need to study brake dust emissions behaviour as well as standardize a procedure and methodology to measure them has rocked. This project aims to contribute in this new study; specifically, the main objectives are, on the one hand, to establish a measurement protocol to measure brake particles emissions during the novel WLTP cycle and, on the other hand, to understand brake wear particles behaviour (among PN and PM concentration, speed and brake temperature influence in the measurements, the impact of brake pressure conditions and pad materials on the results, etc.). Furthermore, emission measurements under standardized technical conditions to harmonize aspects of hardware, enhance the accuracy and definition of the measurement protocol. According to the previous studies in that topic, a Sealed House for Emissions Determination (SHED) with a constant HEPA filtered airflow and a defined extraction has been used to collect the dust coming from the brake system. In addition, a brake dynamometer adapted to the aim of the project has been used, with different particles measurement equipment such as Horiba OBS-ONE PN 23 nm, Dekati HRELPI+ size distributor and eFilter (PM measurements) or PEGASOR Particle Sensor.</p> Along the different testing campaigns performed, interesting events has been found, for instance, the influence of the air flow rate in the SHED system to the final PN and PM concentration results or the particles emitted while the brake system is not acting (brake-off events). In this paper, the most relevant results will be presented: the testing procedure defined for measuring brake dust emissions and the main findings about the particles behaviour. All in all, this study will help finding the conditions where the emissions events are mainly being triggered, leading to possible countermeasures that mitigate their effect.