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On the running-in of brake pads and discs for dyno bench tests
KTH, School of Industrial Engineering and Management (ITM), Machine Design (Dept.). System- o Komponentdesign.ORCID iD: 0000-0003-0696-7506
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2017 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 115, p. 424-431Article in journal (Refereed) Published
Abstract [en]

Running-in process of low metallic brake pads and cast iron discs are investigated using full scale inertia brake dynamometer designed for particle emission studies. The airborne particles are measured using ELPI+ and collected on filters. The pads and disc contact surfaces are studied using microscopy techniques. It is observed that the particle emissions from the new pads and discs are significantly higher compared with the used ones and indicates importance of proper running-in of the pads and disc for wear particle emission tests. The results also indicate that pads and disc pairs which are able to stabilize friction behavior faster will produce less particle emissions which could influence the strategies of brake material formulations or steps during their production.

Place, publisher, year, edition, pages
Elsevier Ltd , 2017. Vol. 115, p. 424-431
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Identifiers
URN: urn:nbn:se:kth:diva-210263DOI: 10.1016/j.triboint.2017.06.008ISI: 000407187900041Scopus ID: 2-s2.0-85020758752OAI: oai:DiVA.org:kth-210263DiVA, id: diva2:1118242
Funder
EU, FP7, Seventh Framework Programme, 324385
Note

QC 20170630

Available from: 2017-06-30 Created: 2017-06-30 Last updated: 2024-03-18Bibliographically approved
In thesis
1. Laboratory measurements of airborne emissions from car brakes for clean air
Open this publication in new window or tab >>Laboratory measurements of airborne emissions from car brakes for clean air
2020 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Brake systems are used to safely stop vehicles. The brake pads are pressed against the brake disc, transforming the kinetic energy of the vehicle into heat to be dissipated. In this process a tribological contact causing wear takes place at the interface of the pads and disc: particles are generated, a fraction of which is airborne and therefore creates an aerosol. To meet demands on air quality and sustainable transport, significant challenges are to find means to measure particles, and provide solutions able to decrease such source of emissions.

Paper A proposes a test cycle executed in an inertia brake dynamometer during which a measurement of the airborne particles is carried out: the sampling point is close to the source of emissions. The experimental results are then analysed to determine how many particles are generated per test section.

Paper B presents a redesign of an inertial disc brake dynamometer with the aim to have clean air while measuring particles, and isokinetic sampling. A comparison in terms of number and size distributions of the brake emissions with and without control of the cleanness of the intake air is studied.

Paper C is the ranking, from the non-exhaust brake emissions point of view, of five different current brake pair materials using the novel redesigned inertia disc brake dynamometer. Particles are both counted, collect on filters and weighed.

Paper D investigates the evolution of the friction performance in terms of friction coefficient and emissions, over five repetitions of the same test procedure – so considering the running-in effect. The friction performance is discussed as a consequence of the dominating wear mechanisms.

Paper E conducts a study on real driving data that are transformed into a brake dynamometer testing procedure by an energy–temperature approach. The consequent emissions study allows the calculation of brake emission factors.

Paper F presents a comparison of the brake particle emissions measurement when volatile and semi-volatile organic compounds (if any), as for exhaust emissions, are thermal treated before being measured.

Paper G illustrates a holistic approach, developed within the REBRAKE EU-financed project, for reducing airborne emissions for car brakes by 50% integrating different perspectives: the tribological testing of the friction pair at different scale levels, the analysis of the relevant wear products and correlated wear mechanisms, the development of specific contact mechanics simulation approaches, and the optimisation of the friction pair materials.

Abstract [sv]

Mekaniska bromsar används för att stoppa fordon på ett säkert sätt. I en skivbroms pressas bromsbeläggen mot bromsskivan och förvandlar fordonets kinetiska energi till värme. I denna process finns en tribologisk kontakt som orsakar slitage i gränssnittet mellan belägg och skiva: partiklar alstras då, av vilka en bråkdel blir luftburna och skapar en aerosol. För att möta krav på luftkvalitet och hållbara transporter är viktiga utmaningar: att utveckla metoder för att mäta luftburna partiklar och att lösningar utvecklas som kan minska utsläppen av luftburna partiklar vid källorna.

Papper A presenterar en testcykel som utförs i en skivbromsdynamometer under vilken en mätning av luftburna partiklarna utförs: provtagningspunkten är nära källan till utsläppen. De experimentella resultaten analyseras för att bestämma antalet luftburna partiklar som genereras per testsektion.

Papper B presenterar en ny design av skivbromsdynamometern (Papper A) med syftet att ha ren bakgrundsluft vid mätning av partiklar och isokinetisk provtagning. En jämförande studie presenteras när det gäller antalet och storleksfördelningen av de luftburna partiklarna med och utan ren bakgrundsluft.

Papper C presenterar en rankning av fem olika skivbromsmaterial i den nya skivbromsdynamometern (Papper B). I jämförelsen utvärderas antalet generade partiklar och partikelmassan genom uppsamling av luftburna partiklar på filter.

Papper D undersöker inkörningseffekter över fem upprepningar av samma testprocedur. Speciellt studeras utvecklingen av friktionsprestanda i termer av friktionskoefficient, ihop med utsläpp i form av luftburna partiklar. Friktionsprestanda diskuteras också som en konsekvens av de dominerande nötningsmekanismerna.

Papper E presenterar en studie av uppmätt kör data som omvandlas till en testprocedur för prov i en bromsdynamometer genom en energitemperaturmetod. Den efterföljande studien gör det möjligt att beräkna emissionsfaktorer för skivbromsar.

Papper F presenterar en jämförelse av mätningen av bromspartiklarnas utsläpp när volatila och organiska föreningar (i förekommande fall), på samma sätt som för avgasutsläpp, termiskt behandlas innan de mäts.

Papper G illustrerar ett holistiskt tillvägagångssätt, utvecklat inom REBRAKE-projektet, ett EU-finansierat projekt, för att minska massan luftburna inandningsbara partiklar från bilbromsar med 50%. Detta genomförs genom att integrera olika perspektiv: tribologiska tester av friktionsparet i olika storleksskalor, analys av nötningsprodukter som korreleras med slitage mekanismer, utveckling av specifika metoder för kontaktmekanisk simulering och optimering av skivbromsens material i den tribologiska kontakten.

Place, publisher, year, edition, pages
Stockholm: KTH Royal Institute of Technology, 2020. p. 52
Series
TRITA-ITM-AVL ; 2020:21
Keywords
Automotive brake, non-exhaust emissions, inertia brake dynamometer, airborne particles, PM10, PN, isokinetic sampling, Rebrake, volatiles, real driving cycle, car brake emission factors, running-in., Bilbroms, icke-avgasemissioner, skivbromsdynamometer, luftburna partiklar, PM10, PN, isokinetisk provtagning, Rebrake, volatiler, verkliga körcykler, emissionsfaktorer, in-körning.
National Category
Tribology (Interacting Surfaces including Friction, Lubrication and Wear)
Research subject
Machine Design
Identifiers
urn:nbn:se:kth:diva-272858 (URN)978-91-7873-530-3 (ISBN)
Public defence
2020-05-29, https://kth-se.zoom.us/webinar/register/WN_eGW21EuVSbqhyxdKBU6PeQ, Stockholm, 09:00 (English)
Opponent
Supervisors
Available from: 2020-05-08 Created: 2020-05-02 Last updated: 2022-06-26Bibliographically approved

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