Abstract
When employed as an engine fuel, ethanol can accumulate in the lubricant during use. Previous work has shown that ethanol contamination affects friction and elastohydrodynamic lubrication (EHL) film formation, and also the growth and stability of anti-wear tribofilms. The present work uses spacer-layer ultrathin interferometry and MTM tests to investigate how ethanol (both hydrated and anhydrous) interacts with friction modifiers in model lubricants. Small proportions (5 wt %) of ethanol were added to solutions of friction modifiers (one MoDTC and three organic friction modifiers) in a Group I base oil. For the three organic friction modifiers, the presence of ethanol promoted the formation of thick viscous boundary films so that very low friction coefficients were measured at low entrainment speeds. For the MoDTC additive, the presence of ethanol prevented the formation of a low friction film at low speeds at 70 °C, but this effect disappeared at 100 °C, probably due to ethanol evaporation.
Highlights
The threats of climate change and depletion of fossil fuels have urged the adoption of policies that can reduce greenhouse gas emissions and dependency on gasoline and diesel
For the three organic friction modifiers, the presence of ethanol promoted the formation of thick viscous boundary films so that very low friction coefficients were measured at low entrainment speeds
Stribeck curves are presented for the blends with the different organic friction modifiers without ethanol contamination, to evaluate how they work at the different test temperatures
Summary
The threats of climate change and depletion of fossil fuels have urged the adoption of policies that can reduce greenhouse gas emissions and dependency on gasoline and diesel. The most widely used such renewable fuel is ethanol. The presence of particulates in the exhaust system is reduced when the fuel contains ethanol [7,8]. It is common knowledge among users that engine parts running on fuels containing large proportions of ethanol tend to suffer more severe wear when compared with gasoline-fueled engines. For this reason, recent work measured the thickness of boundary films formed by the antiwear additive zinc dialkyldithiophosphate (ZDDP)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
