Change search
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • 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
Ageing properties of car fuel-lines;accelerated testing in “close-to-real” service conditions
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
KTH, School of Chemical Science and Engineering (CHE), Fibre and Polymer Technology, Polymeric Materials.
2010 (English)In: Polymer testing, ISSN 0142-9418, E-ISSN 1873-2348, Vol. 29, no 1, 41-48 p.Article in journal (Refereed) Published
Abstract [en]

The use of ethanol-based fuels and tougher restrictions on fuel emissions put a higher demand on car fuel-line (pipe) systems. In this context, it is important to be able to establish and predict properties based on measurements on pipes exposed to real or “close-to-real” environments. This paper presents a new method to age pipes in accelerated “close-to-real” conditions. In this method, the pipe is exposed to circulating fuel on the inside and to air on the outside. The method/equipment allows for non-destructive mechanical testing on “continuous” pipes. The usefulness of the ageing method/system was illustrated on polyamide-12 (PA12) pipes exposed to fuels with varying ethanol content at 50 °C and 110 °C for a maximum of, respectively, ca 3 years and 100 days. “Non-destructive” three-point bending as well as tensile testing was used to assess the ageing-induced changes in mechanical properties. The most conclusive information was that the lowest pipe extensibility (ductility) of dried, previously fuel-exposed pipes was observed at the end of the ageing periods and at the higher ethanol contents. In fact, optical microscopy showed that the tensile fractured pipes, exposed to 25/30 vol. % ethanol at 110 °C (100 h), showed no signs of macroscopic yielding. The trends were interpreted, based also on findings from previous work, as being due to the loss of plasticiser (possibly also PA12 monomers/oligomers) and material “degradation/annealing” processes, the latter involving possibly stabiliser issues.

 

Place, publisher, year, edition, pages
Elsevier , 2010. Vol. 29, no 1, 41-48 p.
Keyword [en]
Pipe; Fuel; Polyamide-12; Ageing; Ethanol
National Category
Other Materials Engineering
Identifiers
URN: urn:nbn:se:kth:diva-12038DOI: 10.1016/j.polymertesting.2009.09.003ISI: 000274562800008Scopus ID: 2-s2.0-72449202605OAI: oai:DiVA.org:kth-12038DiVA: diva2:299997
Note
QC 20110210Available from: 2010-02-25 Created: 2010-02-24 Last updated: 2017-12-12Bibliographically approved
In thesis
1. The Ageing of Fuel Lines Based on Polyamide-12
Open this publication in new window or tab >>The Ageing of Fuel Lines Based on Polyamide-12
2010 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Today, the use of bio-fuels for cars is increasing. There is a wide range of biofuelsavailable world wide, in Sweden ethanol containing fuels are favoured.For car manufacturers there is a need to be able to predict short and long termproperties of fuel lines subjected to ethanol containing fuels to ensure properlong term behaviour. The presented method for ageing in “close to real”environment involved circulating fuel inside the tubes and air on the outside attwo temperatures, 50°C and 110°C. The exposure time was extensive in the50°C case, almost 3 years, and the ageing at 110°C was conducted for 100days. Polyamide-12 was chosen as pipe material, which is also used in realparts. Tensile testing was used to assess the mechanical changes caused byageing. Long ageing times and high ethanol levels resulted in low extensibility.In the case of fuel with 25 vol.% ethanol at 110°C (100 days) the samplesshowed no macroscopic yielding. Even at 50°C a time induced loss ofextensibility was observed (80 vol.% ethanol). However, at ethanol levels of 0and 22 vol.% the extensibility was not reduced even after the 3 years of ageing.The changes at short times were interpreted as being due to loss of plasticizer.The changes at long ageing times were thoroughly investigated. The change incrystallinity, pipe swelling, leaching and the decrease in extensibility were allgreatest in the pipes subjected to ethanol. As expected, the molar massdecreased as the ethanol level increased and a good correlation between molarmass and extensibility was observed. A method for determining the fuelpermeation properties was developed. Fuel lines were subjected to circulatingfuels in the same manner as in the ageing tests and the surrounding air wasanalysed for fuel components with a flame ionisation detector. Higher level ofethanol increased the individual fuel component fluxes as well as the total fluxand also the temperature effect on the flux was significant. Finally it should bementioned, that ethanol was not always an unwanted ingredient; adding a smallamount of ethanol to the ethanol-free fuel prevented premature pipe failure at110°C.

Place, publisher, year, edition, pages
Stockholm: KTH, 2010. 71 p.
Series
Trita-CHE-Report, ISSN 1654-1081 ; 2010:6
Keyword
pipes, ethanol
National Category
Other Materials Engineering
Identifiers
urn:nbn:se:kth:diva-12050 (URN)978-91-7415-552-5 (ISBN)
Public defence
2010-03-19, F3, KTH, Stockholm, 10:00 (Swedish)
Opponent
Supervisors
Note
QC20100722Available from: 2010-02-26 Created: 2010-02-26 Last updated: 2010-07-22Bibliographically approved

Open Access in DiVA

No full text

Other links

Publisher's full textScopusPolymer testing

Search in DiVA

By author/editor
Kallio, Kai J.Hedenqvist, Mikael S.
By organisation
Polymeric Materials
In the same journal
Polymer testing
Other Materials Engineering

Search outside of DiVA

GoogleGoogle Scholar

doi
urn-nbn

Altmetric score

doi
urn-nbn
Total: 90 hits
CiteExportLink to record
Permanent link

Direct link
Cite
Citation style
  • apa
  • harvard1
  • ieee
  • modern-language-association-8th-edition
  • 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