In the context of the PMP Inter-Laboratory Study (ILS), several brake systems were circulated at different laboratories to characterize their brake-wear particulate emissions following the recently developed PMP measurement methodology. Each laboratory is required to employ its own dynamometer, sampling system and measurement instrumentation, including PM2.5, PM10, 10 nm total particle number (PN) and optionally 10 nm solid particle number. The absence of reference measurement instrumentation circulated to the participating laboratories was mainly due to time constraints. Given the challenges associated with the characterization of brake-wear particles and the limited experience with the application of the new methodology, it is important to also assess the contribution of the measurement instrumentation on the repeatability and reproducibility of the novel methodology. To this end, a set of measurement instrumentation was circulated in three laboratories participating in the ILS. The instrumentation included two AVL PM samplers and the associated cyclones for PM2.5 and PM10 quantification, as well as two AVL Particle Counters (APCs). One APC was unmodified and fully compliant with the Global Technical Regulation (GTR) 15 as recently updated for 10 nm measurements. This includes the use of a full-flow CPC with a cut-off size at 10 nm, and a catalytic stripper at 350ºC. The second APC was a modified 10 nm version operating with its heaters deactivated, and the catalytic stripper removed. Both the APCs and the internal CPCs were calibrated in an iso-certified calibration line before the start of the campaign. Their calibration was also validated at the end of the measurement campaign. All three laboratories performed measurements with the two reference brake systems, one of which was tested with two different types of brake-pads. Some additional investigations were performed at each lab. These included testing of two different brake systems, one of which used drum-brakes, as well as investigations of an alternative bedding-in procedure. In this talk an overview of the measured particulate emissions including both mass and number, is presented. The reference brake systems allowed for the assessment of the repeatability and the reproducibility of the measurement results for each metric. These figures when compared to the official statistics of the entire ILS will help assess the contribution of measurement instrumentation on the overall accuracy or the measurement methodology. The talk will also address the robustness as well as improvement potential in the methodology, based on the results with the additional brake systems and the alternative bedding-in procedure.

AVL List GmbH: Dr. Athanasios Mamakos, Dr. Michael Arndt, BMW Group: Mrs. Katharina Kolbeck, Mr Thomas Schroeder; TU Ilmenau: Mr. Christopher Hamatschek, Dr. David Hesse