uu.seUppsala University Publications
Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf
The importance of oil and particle flow for exhaust valve wear - An experimental study
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Tribomaterial)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Tribomaterial)
Uppsala University, Disciplinary Domain of Science and Technology, Technology, Department of Engineering Sciences, Applied Materials Sciences. (Tribomaterial)
2014 (English)In: Tribology International, ISSN 0301-679X, E-ISSN 1879-2464, Vol. 69, 176-183 p.Article in journal (Refereed) Published
Abstract [en]

Oil residue particles have a large impact in protecting the sealing surfaces of heavy duty exhaust valves. To increase the understanding of the mechanism behind this, the wear behavior of exhaust valves subjected to a flow of hot air with controlled amounts of oil particles of three different compositions has been investigated. Air flow without addition of oil was used as a reference. The degree and mechanisms of surface damage proved to be sensitive to the test parameters. Residues from the oils containing additives proved to form protective tribofilms, while the oil without additives promoted agglomeration of wear debris on the sealing surfaces. The dry reference showed severe wear with debris scattered over the surfaces.

Place, publisher, year, edition, pages
2014. Vol. 69, 176-183 p.
National Category
Tribology
Research subject
Engineering Science with specialization in Tribo Materials; Engineering Science with specialization in Materials Science
Identifiers
URN: urn:nbn:se:uu:diva-204467DOI: 10.1016/j.triboint.2013.09.009ISI: 000328183100020OAI: oai:DiVA.org:uu-204467DiVA: diva2:639151
Available from: 2013-08-06 Created: 2013-08-06 Last updated: 2017-12-06Bibliographically approved
In thesis
1. Combustion Valve Wear: A Tribological Study of Combustion Valve Sealing Interfaces
Open this publication in new window or tab >>Combustion Valve Wear: A Tribological Study of Combustion Valve Sealing Interfaces
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

The exhaust valve system of combustion engines experiences a very complex contact situation of frequent impact involving micro sliding, high and varying temperatures, complex exhaust gas chemistry and possible particulates, etc. In addition, the tribological situation in the exhaust valve system is expected to become even worse due to strict future emission regulations, which will require enhanced combustion and cleaner fuels. This will substantially reduce the formation of combustion products that might ease the contact conditions by forming tribofilms on the contacting surfaces. The lack of protective films is expected to result in increased wear of the contact surfaces.

The aim of the work presented in this thesis has been to increase the tribological understanding of the valves. The wear that takes place in the valve sealing interface and how the change in operating conditions affects it have been studied. Such understanding will facilitate the development of future valve designs.

A test rig has been developed. It has a unique design with the ability to insert ppm amounts of media into a hot air flow, in order to simulate different environmental changes, e.g. varying amount and composition of combustion residue particles.

PVD coated valves were evaluated in a dry atmosphere. It was concluded that although some of the coatings showed potential, the substrate could not support the thin, hard coatings.

Investigations with an addition of different oils have been performed. Fully formulated oils proved to build up a protective oil residue tribofilm. This tribofilm has been in-depth analysed and proved to have similar composition and appearance as tribofilms found on low wear field tested valves. With a non-additivated oil, wear particles from the valve seat insert formed a wear particle tribofilm on top of the valve sealing surface. Without any oil the surfaces showed severe wear with wear particles spread over the surfaces.

The results presented give a hint about what to be expected in the future, when the engine oils are replaced with ash less oils with reduced amount of additives and the consumed amount of oil within the cylinders are reduced. 

Place, publisher, year, edition, pages
Uppsala: Acta Universitatis Upsaliensis, 2013. 57 p.
Series
Digital Comprehensive Summaries of Uppsala Dissertations from the Faculty of Science and Technology, ISSN 1651-6214 ; 1058
Keyword
Combustion valves, wear, tribofilm, test rig, combustion residue
National Category
Tribology
Research subject
Engineering Science with specialization in Tribo Materials
Identifiers
urn:nbn:se:uu:diva-204636 (URN)978-91-554-8715-7 (ISBN)
Public defence
2013-09-20, Häggsalen, Ångströmlaboratoriet, Lägerhyddsvägen 1, Uppsala, 10:15 (English)
Opponent
Supervisors
Available from: 2013-08-30 Created: 2013-08-07 Last updated: 2014-01-07

Open Access in DiVA

No full text

Other links

Publisher's full text

Authority records BETA

Forsberg, PeterElo, RobinJacobson, Staffan

Search in DiVA

By author/editor
Forsberg, PeterElo, RobinJacobson, Staffan
By organisation
Applied Materials SciencesApplied Materials Sciences
In the same journal
Tribology International
Tribology

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 891 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • ieee
  • modern-language-association
  • vancouver
  • Other style
More styles
Language
  • de-DE
  • en-GB
  • en-US
  • fi-FI
  • nn-NO
  • nn-NB
  • sv-SE
  • Other locale
More languages
Output format
  • html
  • text
  • asciidoc
  • rtf