Effects of braking conditions on nanoparticle emissions from passenger car friction brakesстатья
Статья опубликована в высокорейтинговом журнале
Информация о цитировании статьи получена из
Web of Science,
Scopus
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 7 июля 2021 г.
Аннотация:Automobile friction brakes generate, in addition to coarse particles generated by mechanical processes, highlyvariable amount of nanoparticles fromhigh temperature processes. The effects of braking conditions – speed, decelerationrate, brake rotor temperatures – on nanoparticle productionwere investigated here, aiming to providepractical guidance for reducing emissions through driving style and traffic management. Typical brake pads and arotor from a common passenger car were subjected, on a brake dynamometer, to three runs of the WLTP brakecycle developed for brake wear particle measurements. Additionally, four sets of common brake pads were subjectedto those parts of standardized brake performance tests believed to be reasonably realistic for commondriving. Particle size distributions (5.6–560 nm electric mobility diameter, without removal of volatiles) showa dominant peak at 10 nmcommensurate to the severity of braking and a non-linear increase of the total particlenumber at higher braking powers and higher total energy dissipated. The average emissions for three runs of theWLTP brake cycle were 3.3 × 1010 particles/km, while the harshest deceleration, 175–100 km/h at 5.28 m·s−2,has produced 8.4 to 38 × 1013 particles, corresponding to 2.5–11.5 thousands of km of WLTP-like driving.While previous studies have correlated higher PN production with higher average brake rotor temperature, amore complex relationship between nanoparticle emissions and a combination of initial rotor temperature,total energy dissipated and braking power has been observed here. From a driver behavior and regulatory perspective, it appears limiting harsh braking and braking from high speeds, possibly through improved drivingpractices, road design and trafficmanagement, may potentially reduce brake wear nanoparticles. Fromthe measurementperspective, it appears that “off-cycle” braking, even if relatively infrequent,may be associated with exponentiallyhigher emissions and non-negligible share of the total emissions, and therefore should not beneglected.