Guest Curators: Dr. Geoff Davis, CSO, HORIBA MIRA; Andrew Everett, Director, A + E Limited; and Dr. Friedrich Wolf-Monheim, Project Manager, Ford Research & Advanced Engineering

Topics & speakers:

• It is all about the plug – Key technology and possibilities of intermodal transportation systems: Univ.-Prof. Dr.-Ing. Kai-Uwe Schröder, Professor, RWTH Aachen University
• Accessible, affordable, self driving technology: Mark Preston, Chief Strategy Officer, StreetDrone
• Cyber resilience and Connected Automated Mobility: Dr. Richard Porter, Technology and Innovation Director, Zenzic

Originally broadcast: 9 July 2020

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.

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.

Non-exhaust emissions in general and brake particle emissions in particular are considered to offer huge potential in the improvement of air quality in densely populated city centers. Legislative authorities started to look into the topic of Brake Dust emissions for a post-Euro 6 regulation. Based on the recommendations of the informal working group of the "particulate measurement program" (PMP) in Europe, HORIBA developed an integrated solution to measure brake particle emissions on a brake dynamometer.

The presentation introduces some of the influencing factors on the particle number emission measurement based on the PMP method. The WLTP-Brake test cycle, dyno settings such as the drafted cooling air adjustement method and other already existing technical requirements are discussed in terms of their influence on the PN emissions. Experimental results outline some of the related challenges before an outlook on the open issues regarding Brake Dust PN is given.