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Tribology Letters

, 67:45 | Cite as

Film Forming Capability of Polymer-Base Oil Lubricants in Elastohydrodynamic and Very Thin Film Regimes

  • Pauline Cusseau
  • Philippe VergneEmail author
  • Laetitia Martinie
  • David Philippon
  • Nicolas Devaux
  • Fanny Briand
Original Paper
  • 42 Downloads

Abstract

The development of high-performance lubricants to insure the separation of mechanical parts, to reduce engine friction and consequently fuel consumption remains a major challenge for oil manufacturers. Polymer additives called viscosity index improvers (VII) have been extensively used to reduce the dependency of the lubricant’s viscosity on temperature, to maintain an acceptable hydrodynamic lubrication in extreme conditions. This work focuses on understanding the role of VII in engine lubricants to bridge their tribological response with their rheological behavior. Simplified lubricants are studied, composed of polymers of different chemistries, molecular weights and conformations added to a mineral base oil. Film thickness measurements are carried out in pure rolling and isothermal conditions to quantify and clarify the effect of polymer addition on the lubricants behavior in the elastohydrodynamic (EHD) and very thin film (VTF) regimes. They are compared with accurate analytical predictions based on rheological models which lead to a good agreement with measured film thicknesses in the EHD regime, whereas some polymer solutions present a significant deviation to EHD predictions at lower thickness, i.e. in the VTF regime. Several explanations are considered, among them the non-Newtonian behavior of the lubricants and the adsorption of some polymers on the surface of the solid bodies.

Keywords

Viscosity index improvers Film thickness capability Elastohydrodynamic regime Rheology Very thin film regime Adsorption 

Notes

Acknowledgements

The authors would like to thank TOTAL for its financial and technical support.

References

  1. 1.
    Holmberg, K., Andersson, P., Erdemir, A.: Global energy consumption due to friction in passenger cars. Tribol. Int. 47, 221–234 (2012)CrossRefGoogle Scholar
  2. 2.
    Stambaugh, R.L., Kinker, B.G.: Viscosity index improvers and thickeners. Chemistry and Technology of Lubricants, pp. 153–187. Springer, Dordrecht (2009)Google Scholar
  3. 3.
    Habchi, W., Vergne, P., Bair, S., Andersson, O., Eyheramendy, D., Morales-Espejel, G.E.: Influence of pressure and temperature dependence of thermal properties of a lubricant on the behaviour of circular TEHD contacts. Tribol. Int. 43, 1842–1850 (2010)CrossRefGoogle Scholar
  4. 4.
    Doki-Thonon, T., Fillot, N., Morales Espejel, G.E., Querry, M., Philippon, D., Devaux, N., Vergne, P.: A dual experimental/numerical approach for film thickness analysis in TEHL spinning skewing circular contacts. Tribol. Lett. 50, 115–126 (2013)CrossRefGoogle Scholar
  5. 5.
    Glass, J.E., Schulz, D.N., Zukoski, C.F.: Polymers as Rheology Modifiers. American Chemical Society, New York (1991)CrossRefGoogle Scholar
  6. 6.
    Bair, S., Vergne, P., Querry, M.: A unified shear-thinning treatment of both film thickness and traction in EHD. Tribol. Lett. 18(2), 145–152 (2005)CrossRefGoogle Scholar
  7. 7.
    Luo, J., Wen, S., Huang, P.: Thin film lubrication part I: study on the transition between EHL and thin film lubrication using a relative optical interference intensity technique. Wear 194, 107–115 (1996)CrossRefGoogle Scholar
  8. 8.
    Hu, Y.Z., Granick, S.: Microscopic study of thin film lubrication and its contributions to macroscopic tribology. Tribol. Lett. 5, 81–88 (1998)CrossRefGoogle Scholar
  9. 9.
    Ma, L., Luo, J.: Thin film lubrication in the past 20 years. Friction 4(4), 280–302 (2016)CrossRefGoogle Scholar
  10. 10.
    Molimard J.: Etude expérimentale du régime de lubrification en film mince - application aux fluides de laminage, PhD thesis (in French). Institut National des Sciences Appliquées de Lyon. No d’ordre: 99ISAL0121 (1999)Google Scholar
  11. 11.
    Gunsel S., Smeeth M., Spikes H.: Friction and Wear Reduction by Boundary Film-Forming Viscosity Index Improvers. In: Proceedings of the SAE International Fall Fuels & Lubricants Meeting and Exhibition, San Antonio (Texas), 14–17 October 1996Google Scholar
  12. 12.
    Martini, A., Ramasamy, U.S., Len, M.: Review of viscosity modifier lubricant additives. Tribol. Lett. 66(2), 58 (2018)CrossRefGoogle Scholar
  13. 13.
    Cusseau, P., Bouscharain, N., Martinie, L., Philippon, D., Vergne, P., Briand, F.: Rheological considerations on polymer-based engine lubricants: viscosity index improvers versus thickeners—generalized Newtonian models. Tribol. Trans. 61(3), 437–447 (2018)CrossRefGoogle Scholar
  14. 14.
    Mary, C., Philippon, D., Devaux, N., Fillot, N., Laurent, D., Bair, S., Vergne, P.: Bridging high pressure rheology and film-forming capacity of polymer-base oil solutions in EHL. Tribol. Int. 93, 502–510 (2016)CrossRefGoogle Scholar
  15. 15.
    Shimizu Y.: Overview of future lubricants for fuel saving in passenger car. In: 2nd International workshop ‘Superlubricity in the automotive real world’, São Paulo (Brasil), May 8–9, 2018Google Scholar
  16. 16.
    ASTM D4741: Standard Test Method for Measuring Viscosity at High Temperature and High Shear Rate by Tapered-Plug Viscometer, ASTM International, West Conshohocken, PA (2017)Google Scholar
  17. 17.
    Bair, S., Mary, C., Bouscharain, N., Vergne, P.: An improved Yasutomi correlation for viscosity at high pressure. Proc. Inst. Mech. Eng. Part J 227(9), 1056–1060 (2013)CrossRefGoogle Scholar
  18. 18.
    Bair, S.: A rough shear-thinning correction for EHD Film thickness. Tribol. Trans. 47, 361–365 (2004)CrossRefGoogle Scholar
  19. 19.
    Westlake, Cameron A.: A study of ultra-thin lubricant films using an optical technique. Proc Inst. Mech. Eng. 182, 75–78 (1967)Google Scholar
  20. 20.
    Albahrani, S., Philippon, D., Vergne, P., Bluet, J.: A review of in situ methodologies for studying elastohydrodynamic lubrication. Proc. Inst. Mech. Eng. J. 230(1), 86–110 (2016)CrossRefGoogle Scholar
  21. 21.
    Hartl, M., Krupka, I., Poliscuk, P., Liska, M., Molimard, J., Querry, M., Vergne, P.: Thin film colorimetric interferometry. Tribol. Trans. 44(2), 270–277 (2001)CrossRefGoogle Scholar
  22. 22.
    Smeeth, M., Spikes, H., Gunsel, S.: Boundary film formation by index improvers’. Tribol. Trans. 39(3), 726–734 (1996)CrossRefGoogle Scholar
  23. 23.
    Mitsui H., Spikes H.A., Suita Y.: Boundary film formation by low molecular weight polymers. In: Proceedings of the 23rd Leeds-Lyon Symposium on Tribology “Elastohydrodynamics”, Leeds 10–13 September 1996, D. Dowson et al. (Editors), Elsevier, Tribology Series 32, 487–500 (1997)Google Scholar
  24. 24.
    Wheeler, J.-D., Vergne, P., Fillot, N., Philippon, D.: On the relevance of analytical film thickness EHD equations for isothermal point contacts: qualitative or quantitative predictions? Friction 4(4), 369–379 (2016)CrossRefGoogle Scholar
  25. 25.
    Chittenden, R.J., Dowson, D., Dunn, J.F., Taylor, C.: A theoretical analysis of the isothermal elastohydrodynamic lubrication of concentrated contacts—Part II. General case, with lubricant entrainment along either principal axis of the Hertzian contact ellipse or at some intermediate angle. Proc. R. Soc. Lond. A 397, 271–294 (1985)CrossRefGoogle Scholar
  26. 26.
    Nijenbanning, G., Venner, C.H., Moes, H.: Film thickness in elastohydrodynamically lubricated elliptic contacts. Wear 176, 217–229 (1994)CrossRefGoogle Scholar
  27. 27.
    Chevalier F., Modélisation des conditions d’alimentation dans les contacts élastohydrodynamiques ponctuels, PhD Thesis (in French), Institut National des Sciences Appliquées de Lyon, No d’ordre 96ISAL0124 (1996)Google Scholar
  28. 28.
    Chaomleffel, J.-P., Dalmaz, G., Vergne, P.: Experimental results and analytical film thickness predictions in EHD rolling point contacts. Tribol. Int. 40(10–12), 1543–1552 (2007)CrossRefGoogle Scholar
  29. 29.
    Hamrock, B.J., Dowson, D.: Isothermal elastohydrodynamic lubrication of point contacts: part IV—Starvation results. J. Lubr. Tech. 99(1), 15–23 (1977)CrossRefGoogle Scholar
  30. 30.
    Wedeven, L.D., Evans, D., Cameron, A.: Optical analysis of ball bearing starvation. J. Lubr. Tech. 93(3), 349–363 (1971)CrossRefGoogle Scholar
  31. 31.
    Tallian, T.E.: On competing failure modes in rolling contacts. ASLE Trans. 10(4), 418–439 (1967)CrossRefGoogle Scholar
  32. 32.
    Luo, J.B., Lu, X.C., Wen, S.Z.: Developments and unsolved problems in nano-lubrication. Prog. Nat. Sci. 11(3), 173–183 (2001)Google Scholar
  33. 33.
    Young, R.J., Lovell, P.A.: Introduction to Polymers, 3rd edn. CRC Press, Boca Raton (2011)CrossRefGoogle Scholar
  34. 34.
    Cann, P.M., Spikes, H.A.: The behavior of polymer solutions in concentrated contacts: immobile surface layer formation. Tribol. Trans. 37(3), 580–586 (1994)CrossRefGoogle Scholar
  35. 35.
    de Gennes, P.-G.: Simple Views on Condensed Matter, 3rd edn. World Scientific, River Edge, NJ (2003)CrossRefGoogle Scholar
  36. 36.
    Müller, M., Topolovec-Miklozic, K., Dardin, A., Spikes, H.A.: The design of boundary film-forming PMA viscosity modifiers. Tribol. Trans. 49, 225–232 (2006)CrossRefGoogle Scholar
  37. 37.
    Krupka, I., Hartl, M.: The influence of thin boundary films on real surface roughness in thin film, mixed EHD contact. Tribol. Int. 40, 1553–1560 (2007)CrossRefGoogle Scholar
  38. 38.
    Muraki, M., Nakamura, K.: Film-forming properties and traction of non- functionalized polyalkylmethacrylate solutions under transition from elastohydrodynamic lubrication to thin-film lubrication. Proc. Inst. Mech. Eng. Part J. 224(1), 55–63 (2010)CrossRefGoogle Scholar
  39. 39.
    Cosimbescu, L., Vellore, A., Ramasamy, U.S., Burgess, S.A., Martini, A.: Low molecular weight polymethacrylates as multi-functional lubricant additives. Eur. Polym. J. 104, 39–44 (2018)CrossRefGoogle Scholar
  40. 40.
    Spikes, H.A., Cann, P.M.: The thickness and rheology of boundary lubricating films. Proc. Int. Tribol. Conf. YOKOHAMA’95 2, 1089–1094 (1995)Google Scholar

Copyright information

© Springer Science+Business Media, LLC, part of Springer Nature 2019

Authors and Affiliations

  1. 1.Univ Lyon, INSA Lyon, CNRS, LaMCoS - UMR5259VilleurbanneFrance
  2. 2.TOTAL, Centre de Recherche de SolaizeSolaizeFrance

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