Brake wear emissions can be reduced by altering the surface of brake disks. A parametric study using a gray cast iron and a laser-cladded brake disk was performed in a pin-on-disk experiment with integrated optical pin surface characterization and particle emission measurement. Significant differences in the friction, wear and emission behavior are present. The high wear-resistance of the laser-cladded disk led to a reduction of 70% of the particle number emission relative to the gray cast iron disk, but the coefficient of friction was unstable. The surface of the pin used with the gray cast iron showed an initial large debris extension and protruding patches that were removed at high braking energies, exposing white patches and creating holes. These observations correspond to known processes from the plateau theory. The surface of the pin used with the laser-cladded disk showed a topography dominated by holes with almost no protruding patches. The braking condition did not influence the pin surface, implying that the disk and not solely the pin surface might be governing the friction process, and therefore challenging the applicability of the plateau theory to laser-cladded disks. To further study this aspect, a segmentation method was developed for the pin surface images and topographical data to extract and quantify different features on the pin, such as debris, patches, holes and the tribolayer. The correlation of the surface coverage ratios of the feature classes with the braking conditions (speed and applied pressure), the coefficient of friction and the emissions confirmed the differences between the gray cast iron and laser-cladded brake disk.
The focus of this article is on the measurement of tire and road wear particles (TRWPs) during vehicle operation. The long-term objective is to determine the sources of particulate matter. Consequently, the development of sustainable tires can be supported in the future by identifying factors influencing the concentration of particulate matter in vehicle-based tire tests. In an initial campaign, a test vehicle was equipped with a total of seven low-cost sensors (LCSs) for measurement campaigns on an isolated outdoor test track. The purpose of this was to evaluate the particle measurements in combination with GNSS data and driving data such as acceleration and speed. The potential observed in the initial investigation led to further investigations with an advanced, interconnectable modular particle and environmental sensor system (iMPES), which was developed in-house. The iMPES records measurement data for PM10 via the PMS7003 and PM100 via the SDS198 at 1 Hz over a period of up to 6 h, using a mobile power supply. The findings of the study indicate a robust characterization of the particle concentrations over the temporal and local course of the campaign drives. The results demonstrate the potential of the method to be part of a methodology to differentiate the particle sources and to derive influencing factors on the particulate matter concentration. The paper proposes a methodology for the mapping and analysis of lap-based data on a normalized route. Consequently, an inquiry into the local and driving-dependent dynamics is conducted, alongside a comparison with driving data.