On the influence of car brake system parameters on particulate matter emissions

Alemani, Mattia; Wahlström, Jens; Olofsson, Ulf

doi:10.1016/j.wear.2017.11.011

Cited by 58 publications

(65 citation statements)

References 27 publications

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“…The conventional brake material was replaced by a novel material composition developed in the EU project LOWBRASYS. The new system-not yet at a series production status-consists of a novel cast-iron rotor coated by an approximately 70 µm thin surface of WC-CoCr using high-velocity oxygen fuel (HVOF) coatings [29][30][31]. The lining of the novel friction material contained geopolymers that were based on alkaline-activated blast furnace slag [42].…”

Section: Methodsmentioning

confidence: 99%

“…Open system [37] Closed system [28] Closed system [29] Closed system [30] Closed system [31] Closed system [32] Closed system [38] Brake Dyno…”

Section: Referencementioning

confidence: 99%

“…Brake wear particles can be studied in a relatively controlled environment in the laboratory or under uncontrolled real-world conditions on the road [19,20]. Laboratory studies can be carried out at full vehicle level on a roller chassis bench [21], at brake couple level on a brake dynamometer [11,[22][23][24][25][26][27], or at brake component level on a pin-on-disc configuration [28][29][30][31][32]. Table 1 gives an overview of different methods applied by different researchers for sampling and measuring brake wear particles.…”

mentioning

confidence: 99%

“…Testing conditions at pin-on-disc configurations are considerably different from the real conditions of the automotive brakes operation. This includes the size of the tested friction couple, the adopted sliding velocity and deceleration, and the particle generation rate as well as the airflow regime [28,30]. According to Kukutschová et al [33], these differences result in lower energy generated per area which can also influence parameters of wear particles [30].…”

mentioning

confidence: 99%

“…This includes the size of the tested friction couple, the adopted sliding velocity and deceleration, and the particle generation rate as well as the airflow regime [28,30]. According to Kukutschová et al [33], these differences result in lower energy generated per area which can also influence parameters of wear particles [30]. Overall, pin-on-disc configurations seem to be the ideal solution for investigating the underlying phenomena but not for studying the levels of brake particle emissions at vehicle level.…”

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Brake Wear Particle Emissions of a Passenger Car Measured on a Chassis Dynamometer

et al. 2019

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Brake wear emissions with a special focus on particle number (PN) concentrations were investigated during a chassis dynamometer measurement campaign. A recently developed, well-characterized, measurement approach was applied to measure brake particles in a semi-closed vehicle setup. Implementation of multiple particle measurement devices allowed for simultaneous measurement of volatile and solid particles. Estimated PN emission factors for volatile and solid particles differed by up to three orders of magnitude with an estimated average solid particle emission factor of 3·10 9 # km −1 brake −1 over a representative on-road brake cycle. Unrealistic high brake temperatures may occur and need to be ruled out by comparison with on-road temperature measurements. PN emissions are strongly temperature dependent and this may lead to its overestimation. A high variability for PN emissions was found when volatile particles were not removed. Volatiles were observed under high temperature conditions only which are not representative of normal driving conditions. The coefficient of variation for PN emissions was 1.3 without catalytic stripper and 0.11 with catalytic stripper. Investigation of non-braking sections confirmed that particles may be generated at the brake even if no brakes are applied. These "off-brake-event" emissions contribute up to about 30% to the total brake PM 10 emission.EFs depend on parameters like the type of the friction material, the type of the brake assembly, and the applied driving conditions [11]. Following the development of a WLTP-based braking cycle in 2018 [7], most studies focused on the application of realistic braking patterns, but still the range of reported EFs remained relatively wide [12][13][14]. Similarly, experimentally measured brake wear PM 2.5 EFs vary from 0.1 mg·km −1 to 5 mg·km −1 per vehicle [8,11,13]. Finally, particle number (PN) EFs reported by various researchers also appear to be inconsistent [12,[14][15][16]. This is probably due to more variations on the setup and measurement protocols when PN related studies are examined. One has to keep in mind that traffic related PN emissions, particularly ultrafine particle emissions, are becoming more relevant due to demonstrated negative health effects [17,18].One important reason for the observed inconsistencies in the measurement of PM and PN EFs is the lack of a standardized methodology for sampling and measuring brake wear particle emissions [7]. Indeed, in most references provided previously, different sampling and measurement setups were employed. Brake wear particles can be studied in a relatively controlled environment in the laboratory or under uncontrolled real-world conditions on the road [19,20]. Laboratory studies can be carried out at full vehicle level on a roller chassis bench [21], at brake couple level on a brake dynamometer [11,[22][23][24][25][26][27], or at brake component level on a pin-on-disc configuration [28][29][30][31][32]. Table 1 gives an overview of different methods applied by different researchers...

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Section: Methodsmentioning

confidence: 99%

“…Open system [37] Closed system [28] Closed system [29] Closed system [30] Closed system [31] Closed system [32] Closed system [38] Brake Dyno…”

Section: Referencementioning

confidence: 99%

mentioning

confidence: 99%

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confidence: 99%

mentioning

confidence: 99%

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Brake Wear Particle Emissions of a Passenger Car Measured on a Chassis Dynamometer

et al. 2019

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Characterization of benzoxazine resins for brake pad friction materials manufacturing

Carlevaris

Menapace

Straffelini

et al. 2022

J Therm Anal Calorim

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Phenolic resins are the most commonly used binders in brake pads for automotive disc brake systems owing to their affordability and thermal properties. However, they also show some limitations related to their crosslinking mechanism. Benzoxazine resins present themselves as possible alternatives for this application by providing enhanced thermal properties as well as other industrially attractive characteristics such as lower moisture absorption and unlimited shelf life. This study investigates the thermal properties of two different benzoxazine resins, with the aim of assessing their capabilities as binder for brake pad and of understanding how to process them in order to actually employ them as such. DSC, TGA, hardness and tribological analyses were carried out on neat resin samples and on friction materials containing them as binder. The presence of several concurring reactions was detected during the crosslinking reaction of benzoxazine resins. The benzoxazine resins showed lower mass loss respect to a phenolic resin in the temperature range of interest for commercial brake pads application. Friction material containing benzoxazine resin binder showed promising tribological results.

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The Impact of Composition in Non-steel and Low-Steel Type Friction Materials on Airborne Brake Wear Particulate Emission

Kim

Shim

Kwon³

et al. 2020

Tribol Lett

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In this work, airborne brake wear particulate matter (PM) emissions from a brake system were investigated by time-resolved and temperature-dependent measurement using a dynamometer. The measurement was performed for representative friction materials, 3 low-steel (LS) and 4 non-steel (NS), which are currently in worldwide use. The PM emission factor was found to be varied as large as by one order of magnitude depending on the composition of friction materials(pads). The airborne particle mass emissions from the LS materials ranged from 1.88 to 3.14 mg/km/vehicle, while the emissions from the NS ranged from 0.3 to 2.34 mg/km/vehicle, which is, in general, smaller than the LS. The time-resolved data imply that particle emissions in the extra-high-speed region of the WLTC cycle, where friction occurs at high temperature (T disk > 150 °C), is much higher than in the low-speed region, and determines the total PM mass emission factor. It was found that the friction materials containing metals such as Cu and Sn (LS-2/-3 and NS-4/-5) exhibited a lower PM emission factor. This result suggests that copper and tin, which forms an effective lubricating tribolayer in the interface between the pad and disk at high temperature, remarkably reduces PM emissions. It has been also found that the surface roughness of worn brake pads is positively proportional to PM emissions according to surface topography analysis, which is consistent with composition effect. These findings suggest that tribological engineering to provide sliding frictional behavior at elevated temperature is crucial to reducing PM emissions.

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On the influence of car brake system parameters on particulate matter emissions

Cited by 58 publications

References 27 publications

Brake Wear Particle Emissions of a Passenger Car Measured on a Chassis Dynamometer

Brake Wear Particle Emissions of a Passenger Car Measured on a Chassis Dynamometer

Characterization of benzoxazine resins for brake pad friction materials manufacturing

The Impact of Composition in Non-steel and Low-Steel Type Friction Materials on Airborne Brake Wear Particulate Emission

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