Study of Brake Wear Particle Emissions: Impact of Braking and Cruising Conditions
A novel measurement setup is designed, constructed, and validated by theoretical simulations and by experiments enabling sensitive and loss-free brake particle emission investigations. With the goal to simulate realistic driving, a 3 h subsection of the Los Angeles City Traffic (LACT) cycle is selec...
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Veröffentlicht in: | Environmental science & technology 2019-05, Vol.53 (9), p.5143-5150 |
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Format: | Artikel |
Sprache: | eng |
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Zusammenfassung: | A novel measurement setup is designed, constructed, and validated by theoretical simulations and by experiments enabling sensitive and loss-free brake particle emission investigations. With the goal to simulate realistic driving, a 3 h subsection of the Los Angeles City Traffic (LACT) cycle is selected as test cycle. The tests are performed with the front brake of a midsize passenger vehicle under both static laboratory and more dynamic realistic conditions that include parasitic drag and vehicle brake temperatures (advanced vehicle simulations). A PM10 emission factor of around 4.6 mg km–1 brake–1 is determined. During five cycle runs the emission factor in terms of particle number decreases by 1 order of magnitude. This decrease is accompanied by a shift of the critical brake temperature T crit, at which ultrafine particle emissions occur, from 140 to 170 °C. Investigations with advanced vehicle simulations generate brake temperatures below T crit and consequently do not show ultrafine particle emissions above background level. A particle number emission factor of approximately 4.9 × 1010 km–1 brake–1 is estimated for realistic vehicle brake temperatures. Particle formation during cruising is clearly identified. The brake drag is estimated to contribute about 34% to the total airborne particle mass emission. |
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ISSN: | 0013-936X 1520-5851 |
DOI: | 10.1021/acs.est.8b07142 |