Brake and Clutch Emissions Generated During Vehicle Operation

This review article comprises of three parts. Firstly, reports of brake manufacturers on the beneficial impact of solid lubricants for pad formulations are surveyed. Secondly, since tribofilms were identified to play a crucial role in friction stabilization and wear reduction, the knowledge about tribofilm structures formed during automotive braking was reviewed comprehensively. Finally, a model for simulating the sliding behavior of tribofilms is suggested and a review on modelling efforts with different model structures related to real tribofilms will be presented. Although the variety of friction composites involved in commercial brake systems is very broad, striking similarities were observed in respect to tribofilm nanostructures. Thus, a generalization of the tribofilm nanostructure is suggested and prerequisites for smooth sliding performance and minimal wear rates have been identified. A minimum of 13 vol % of soft inclusions embedded in an iron oxide based tribofilm is crucial for obtaining the desired properties. As long as the solid lubricants or their reaction products are softer than magnetite, the main constituent of the tribofilm, the model predicts smooth sliding and minimum wear.

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“…Methods Observations Authors' Interpretation Comments [43] 1973 LM TEM Much less coarse and fine asbestos fibers observed, as expected.…”

Section: Referencementioning

confidence: 58%

The Role of Solid Lubricants for Brake Friction Materials

Österle

Дмитриев

2016

Lubricants

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“…This matrix material serves to increase the sedimentation rate and could, therefore, alter the potential respirability of this type of dust. The opportunity for workplace exposure during this aspect of automotive servicing (with new brake components) can be appreciated by an example offered by Jacko et al [1973] who projected that in 1973 as much as 15% of asbestos material could be lost during grinding and drilling of new brake friction products. Based on the amount of asbestos utilized in these products during 1973 this assumption would extrapolate to some 15 tons of asbestos containing materials that would be generated by mechanics during the traumatic physical processes of crushing, abrading, and drilling the original material.…”

Section: Introductionmentioning

confidence: 99%

“…This DHHS (NIOSH) publication noted that ''chrysotile is used almost exclusively and comprises from 40 to 50% of brake linings'' in asbestos containing brakes. To give an indication of the historical magnitude of asbestos consumption in these applications Jacko et al [1973] reported that the calculated annual use was 118 million pounds (prior to grinding and drilling) in brake products and 4.5 million pounds in clutch friction material.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the size and type of free particulates collected from unused asbestos‐containing brake components as related to potential for respirability

Atkinson

O’Sullivan

Zuber

et al. 2004

American J Industrial Med

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We conclude that any manipulation of new asbestos containing brake components would be expected to yield free dust containing chrysotile asbestos of respirable size. That the vast majority of these fibers and particulates would not be counted as regulated fibers rendering assessment of potential exposures in the work place, based on data of Permissible Exposure Limits or Regulated Fibers, questionable.

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“…There is no data or chemical testing showing that amphibole asbestos was ever used in the manufacture of brakes. In fact, virtually all of the scientific data demonstrate that chrysotile was the mineral form universally used for this purpose in the United States and Europe (Rosato, 1959;Lynch, 1968;Anderson et al, 1973;Langer and McCaughey, 1982;Weir et al, 2001;Blake et al, 2003;Madl et al, 2008;Sheehy et al, 1989;Jacko et al, 1973).…”

mentioning

confidence: 99%