Wear Test Procedure on Inertia Dynamometer for Brake Friction Materials

Mullite reinforced composites were produced by the injection molding technique to develop environmentally friendly friction materials for automotive applications. In order to examine the effect of mullite content on the friction and wear properties, two different specimens containing 10wt% and 30wt% of mullite were respectively fabricated and wear-tested by using the plate-on-disc type sliding friction and wear test machine. The sliding friction and wear test demonstrated that both specimens show similar tendencies at different sliding speeds under a low load of 2.9N. In comparison with common glass fiber reinforced composites, both of the mullite reinforced composites exhibited a lower wear rate at room temperature.

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Testing of Alternative Disc Brakes and Friction Materials Regarding Brake Wear Particle Emissions and Temperature Behavior

Atmosphere ◽

10.3390/atmos12040436 ◽

2021 ◽

Vol 12 (4) ◽

pp. 436

Author(s):

David Hesse ◽

Christopher Hamatschek ◽

Klaus Augsburg ◽

Thomas Weigelt ◽

Alexander Prahst ◽

...

Keyword(s):

Tungsten Carbide ◽

Test Procedure ◽

Wear Particle ◽

Emission Factors ◽

Particle Emission ◽

Particle Emissions ◽

Friction Materials ◽

Disc Brakes ◽

Brake Wear ◽

Carbon Ceramic

In this study, different disc brakes and friction materials are evaluated with respect to particle emission output and characteristic features are derived. The measurements take place on an inertia dynamometer using a constant volume sampling system. Brake wear particle emission factors of different disc concepts in different sizes are determined and compared, using a grey cast iron disc, a tungsten carbide-coated disc and a carbon ceramic disc. The brakes were tested over a section (trip #10) novel test cycle developed from the database of the worldwide harmonized Light-Duty vehicles Test Procedure (WLTP). First, brake emission factors were determined along the bedding process using a series of trip-10 tests. The tests were performed starting from unconditioned pads, to characterize the evolution of emissions until their stabilization. In addition to number- and mass-related emission factors (PM2.5–PM10), the particle size distribution was determined. Another focus was the evaluation of temperature ranges and the associated challenges in the use of temperature readings in a potential regulation of brake wear particle emissions. The results illustrate the challenges associated with establishing a universal bedding procedure and using disc temperature measurements for the control of a representative braking procedure. Using tungsten carbide coated discs and carbon ceramic discs, emission reduction potentials of up to 70% (PM10) could be demonstrated along the WLTP brake cycle. The reduction potential is primarily the result of the high wear resistance of the disc, but is additionally influenced by the pad composition and the temperature in the friction contact area.

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