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Investigations of airborne tire and brake wear particles using a novel vehicle design

Manuel Löber, Linda Bondorf, Tobias Grein, Sven Reiland, Steffen Wieser, Fabius Epple et al. · 2024 · 8 citationsRead the paper

Non-exhaust emissions have become an increasingly important issue as their levels continue to rise and the health effects of particulate matter (PM) are more widely discussed. To address this issue, a vehicle demonstrator with integrated emission reduction of tires and brakes was developed as part of the Zero Emission Drive Unit Generation-1 (ZEDU-1) project. This novel concept includes the removal of tire road wear particles (TRWP) with a strong ventilation/filtering system and an enclosed multi-disk brake, making it a suitable tool for the investigation of non-exhaust emissions. Particle number (PN) and particle size distribution (PSD) measurements down to 2.5 nm were performed on a chassis dynamometer and on a test track. Due to the low background concentrations on the chassis dynamometer, it is possible to distinguish between tire and brake wear and to characterize even a small number of particle emissions. It could be shown that about 30 % less particles are emitted by the vehicle, when using the novel multi-disk brake instead of the conventional brake. The highest TRWP emissions were collected during acceleration and harsh braking. Characterization of the collected particles using scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS) revealed diverse particle shapes and differences between particles generated on the dynamometer and on a test track.

What the full text shows

Working prototype
  • The novel multi-disk brake reduces total non-exhaust emissions compared to conventional brakes. — 30% lower (Measured on a chassis dynamometer during five braking events of increasing deceleration)
  • Tire road wear particle (TRWP) emission factor for the right front tire on a chassis dynamometer. — 2.1 x 10^10 #/tire km (WLTC cycle, particles 7 nm to 2 µm)
  • Tire road wear particle (TRWP) emission factor for the right front tire on a test track. — 1.0 x 10^10 #/tire km (WLTC cycle, particles 7 nm to 2 µm)
  • TRWP emissions on the test track for the front axle in the coarse size range. — 3.0 x 10^8 #/veh km (WLTC cycle, particles 0.3 to 10 µm)
  • TRWP emissions on the chassis dynamometer for the front axle in the coarse size range. — 4.7 x 10^7 #/tire km (WLTC cycle, particles 0.3 to 10 µm)
  • TRWP particle size distribution (PSD) differs between test environments. — 6-50 nm (dynamometer) vs 60-90 nm (test track) (During acceleration peaks in WLTC cycle)
Setup
ZEDU-1 vehicle demonstrator tested on a DLR chassis dynamometer and the Bosch test facility (oval track) using the WLTC cycle.
How
A battery-electric vehicle demonstrator was equipped with an encapsulated multi-disk brake and a tire housing with a fan-driven suction/filtration system (up to 250 l/s). Emissions were measured using Condensation Particle Counters (CPC), an Engine Exhaust Particle Sizer (EEPS), and an Optical Particle Sizer (OPS), with collected particles analyzed via SEM and EDS.
Limitations
Test track measurements were overlapped by high background concentrations. · EDS chemical assignment is difficult due to road dust covering particles. · Top speed was limited to 120 km/h (below WLTC 131 km/h) to protect the battery.

Summarized by Gemma 4 from the open-access full text · 8 Oct 2026. Read it