The use of improvers of viscosity index mixed with engine oil to enhance film thickness of lubricant, have been tribologically studied by the optical interferometry technique. The viscosity index improvers (PTFE and MoS2) effect on the mixed engine oil, were experimentally studied and compared with benchmark engine oil without added viscosity improvers. The outcome of the improvers, rolling velocity and contact pressure on the engine oil film formation in a steel ball, loaded on a flat glass surface in point contact, was investigated. The two-beam light source optical interferometry principle was used in this experiment. The Hamrock and Dowson's numerical methods for EHL film formation was compared with the tribo-test results. The base engine oil for this study is SAE 30 while PTFE and MoS2 powdered lubricants were blended with the engine oil. The viscosities of the lubricants ranged from 0.0109 Pa s to 0.255 Pa s. The rolling speed and the loads were distinctly selected between 0.189 m/s to 0.641 m/s and 1 N to 2.6 N, respectively. The steady and rolling state was used to evaluate the stability of the film thickness at contact point. The viscosity improvers were observed to have significant positive influence on the film thickness behaviour.
KhonsariMM, BooserER.Applied tribology: Bearing Design and lubrication, Sec Ed.John Wiley & Sons, Ltd. The Atrium, Southern Gate, Chichester, West Sussex P0198SQ, England; 2008.
2.
GelinckERM.Mixed Lubrication of Line Contacts, Ph.D. thesis, Univ. of Twente, The Netherlands (1999).
3.
SchipperDJ.Transitions in the Lubrication of Concentrated Contacts, Ph.D. thesis, University of Twente, The Netherlands (1988).
4.
GoharR.Elastohydrodynamics. Ellis Horwood Series in Mechanical Engineering, 2001.
5.
BraithwaiteER, GreeneAB.A Critical analysis of the performance of molybdenum. Wear. 1978;46:405–433. doi: 10.1016/0043-1648(78)90044-3
6.
GreeneAB, RisdonTJ.Effect of mo-containing oil soluble friction modifiers on engine fuel economy and gear oil efficiency. SAE Tech Paper 811187, (1981).
7.
MitchellPS.Oil-soluble Mo-S compounds as lubricant additives. Wear. 1984;100:281–300. doi: 10.1016/0043-1648(84)90017-6
8.
CooperHS, DamerellVR.Lubricants suitable for various uses. US Patent 2156803 (1939).
9.
RisdonTJ, GrestyDA.An historical review of reductions in fuel consumption of United States and European engines with MoS2. SAE Technical Paper 750674 (1975).
10.
WhiteHS, ZeiD.Static friction tests with various metal combinations and special lubricants. J Res Nat Bur Stand. 46, 292–298 (1951) Tribol Lett (2015) 60:5 Page 23 of 265.
11.
GansheimerJ, HolinskiR.Molybdenum disulfide in oils and greases under boundary conditions. Trans ASME J Tribol. 1973;95:242–246.
12.
GänsheimerJ, HolinskiR.A study of solid lubricants in oils and greases under boundary conditions. Wear. 1972;19:439–449. doi: 10.1016/0043-1648(72)90317-1
13.
GrestyDA, KunzEJ, RisdonTJ.The effect of MoS2 based lubricants on automotive gear efficiency and operating temperatures. SAE Technical Paper 770834 (1977).
14.
BraithwaiteER, GreeneAB.A critical analysis of the performance of molybdenum compounds in motor vehicles. Wear. 1978;46:405–432. doi: 10.1016/0043-1648(78)90044-3
15.
GreeneAB, RisdonTJ.The effect of molybdenum-containing, oil-soluble friction modifiers on engine fuel economy and gear oil efficiency. SAE Technical Paper 811187 (1981).
16.
YakovE, ThomasJR.Molybdenum disulfide in lubricant applications – a review, Presented at the 12 Lubricating Grease Conference, NLGI-India Chapter, 28–30 January 2010.
17.
LansdownAR.Molybdenum disulphide lubrication, tribology series, vol. 35, 1st ed., Elsevier, Amsterdam; New York, p.380 28th May 1999.
18.
BenningtonJE, ColeDE, GhirlaPJ, Stable colloid additives for engine oils - potential improvement in fuel economy. SAE Techn. Paper 750677 (1975).
19.
ReickFG.Lubricant oil containing polytetrafluoroethylene and fluorochemical surfactant. U.S. Patent No. 4,224,173. Sep. 23, 1980.
20.
ReickFG.Energy saving lubricants containing colloidal PTFE. Lub Eng. 1982;38:635–646.
21.
BijweJ, SharmaS, SharmaM, Exploration of potential of solid lubricants and short fibers in Polyetherketone (PEK) composites. Wear. 2013;301(1–2):810–819. doi: 10.1016/j.wear.2013.01.059
22.
SharmaM, BijweJ.Surface designing of carbon fabric polymer composites with nano and micron sized PTFE particles. J Mater Sci. 2012;47:4928–4935. doi: 10.1007/s10853-012-6367-5
FernándezRE, MinondoI, GarcíaCD.The effectiveness of PTFE nanoparticle powder as an EP additive to mineral base oils. Wear. 2007;262(11–12):1399–1406. doi: 10.1016/j.wear.2007.01.022
26.
MukeshKD, JayashreeB, RamakumarSSV.PTFE based nano-lubricants. Wear. 2013;306(80–88).
27.
FernándezER, MinondoI, GarcíaDC.Rolling contact fatigue life of AISI 52100 steel balls with mineral and synthetic polyester lubricants with PTFE nanoparticle powder as an additive. Wear. 2009;266:671–677. doi: 10.1016/j.wear.2008.08.020
28.
MukeshKD, JayashreeB, RamakumarSSV.Nano-PTFE: new entrant as a very promising EP additive. Tribol Int. 2015;87:121–131. doi: 10.1016/j.triboint.2015.01.026
29.
ChinasFC, SpikesHA.Mechanism of action of colloidal solid dispersions. J Tribol. 2003;125(3):552–557. doi: 10.1115/1.1537752
30.
BakuninVN, SuslovYA, KuzminaGN, Recent achievements in the synthesis and application of inorganic nanoparticles as lubricant components. Lubr Sci. 2005;17(2):127–145. doi: 10.1002/ls.3010170202
31.
WuYY, TsuiWC, LiuTC.Experimental analysis of tribological properties of lubricating oils with nanoparticle additives. Wear. 2007;262:819–825. doi: 10.1016/j.wear.2006.08.021
32.
ChoiY, LeeC, HwangY, Tribological behavior of copper nanoparticles as additives in oil. Curr Appl Phys. 2009;9:124–127. doi: 10.1016/j.cap.2008.12.050
33.
YousifAE.Liquid-solid lubricants in conditions pertinent to isothermal elastohydrodynamic line contact lubrication. Tribol Ind. 2009;31:47–52.
34.
SternlichtB, LewisP, FlynnP.Theory of lubrication and failure of rolling contacts. ASME J Basic Eng. 1961;83:213–226. doi: 10.1115/1.3658927
35.
GhoshMK, HamrockBJ.Thermal elastohydrodynamic lubrication of line contacts. Trans ASLE. 1985;28(2):159–171. doi: 10.1080/05698198508981608
36.
SalehizadehH, SakaN.Thermal non-Newtonian elastohydrodynamic lubrication of rolling line contacts. ASME J Tribol. 1991;113:481–491. doi: 10.1115/1.2920649
37.
GreenwoodJA, KauzlarichJJ.Inlet shear heating in elastohydrodynamic lubrication. Trans ASME J Lubr Technol. 1973;95(4):401–416. doi: 10.1115/1.3451843
38.
HuangP.Numerical calculation methods elastohydrodynamic lubrication published 2013 by Tsinghua University Press, Beijing, P. R. China.
GoharR, CameronA.Optical measurement of oil film thickness under elasto-hydrodynamic lubrication. Nature. 1963;200:458–459. doi: 10.1038/200458b0
41.
WestlakeFJ, CameronA.A study of ultra–thin lubricant films using an optical technique. Proc Inst Mech Eng. 1967–1968;182(7):75–78 Pt. 3G.
42.
SpikeHA, GuangtengG.Properties of ultra lubricating film using wedged spacer layer optical interferometry. In: DowsonD, editor. Proceedings of the 14th Leeds-Lyon Symposium on Tribology, Marcel Dekker, Inc., New York, USA. 1988. p. 275–279.
43.
JohnstonGJ, WayteR, SpikesHA.The measurement and study of very thin lubricant films in concentrated contact. STLE Tribol Trans. 1991;34(2):187–194. doi: 10.1080/10402009108982026
44.
CannPM, SpikesHA, HutchinsonJ.The development of a spacer layer imaging method (SLIM) for mapping elastohydrodynamic contacts. STLE Tribol Trans. 1996;39:915–921. doi: 10.1080/10402009608983612
45.
SpikesHA, CannPM.The development and application of the spacer layer imaging method for measuring lubricant film thickness. Proc Inst Mech Eng Tribol. 2001;215(J3):261–277. doi: 10.1243/1350650011543529
46.
GlovneaRP, ForrestOAV, SpikesHA.Measurement of sub-nanometer lubricant films using ultra-thin film interferometry. Tribol Lett. 2003;15:217–230. doi: 10.1023/A:1024809102533
47.
BornM, WolfE.Principle of Optics. 5th ed.Pergamon Press, Oxford; 1975; p. 257–270.
48.
ZhuangSL, QianZB.Optical transfer function. Beijing: China Machine Press; 1981.
49.
TheoM, GeorgL.Lubricants and lubrication. 2nd ed. Edited by Th. Mang and W. Dresel, Willey-VCH Verlag GmbH & Co. KGaA, Weinheim, Germany; 2007.
50.
GyimahKG.Study of TEHL point contact lubricated with two-phase (liquid-solid) lubricants [PhD dissertation]. South China University of Technology, Guangzhou, China; 2014.
51.
MoesH.Lubrication and Beyond, Lecture Notes, Code 115531. Enschede: Twente University Press; 2000; 366 p.
52.
VennerCH.Multilevel solution of the EHL line and point contact problems [PhD dissertation]. Twente University, Netherlands; 1991, 318 pp.
53.
HookeCJ.Minimum film thickness in lubricated point contacts operating in the elastic piezoviscous regime. Proc IMechE Part C J Mech Eng Sci. 1988;202(C2):73–84. doi: 10.1243/PIME_PROC_1988_202_092_02
54.
HamrockBJ, DowsonD.Isothermal elastohydrodynamic lubrication of point contacts: part 1 – theoretical formulation. Trans ASME J Lubr Technol. 1976;98:223. doi: 10.1115/1.3452801
55.
HamrockBJ, DowsonD.Isothermal elastohydrodynamic lubrication of point contacts: part 2 – ellipticity parameter results. Trans ASME J Lubr Technol. 1976;98:375. doi: 10.1115/1.3452861
56.
HamrockBJ, DowsonD.Isothermal elastohydrodynamic lubrication of point contacts: part 3 – fully flooded results. Trans ASME J Lubr Technol. 1977;99:264. doi: 10.1115/1.3453074
57.
HamrockBJ, DowsonD.Isothermal elastohydrodynamic lubrication of point contacts: part 4 – starvation results. Trans ASME J Lubr Technol. 1977;99:15. doi: 10.1115/1.3452973
58.
ZhangC, LuoJ, WenS.Exploring micro polar effects in thin film lubrication, Science in China Ser. G Physics. Mech Astron. 2004;47:65–71. doi: 10.1360/03yb0230
59.
LiranM, ZhangC.Discussion on the technique of relative optical interference intensity for the measurement of lubricant film thickness. Trib Lett. 2009;36:239–245. doi: 10.1007/s11249-009-9479-6
60.
DumitruMF.Study of film formation in EHD contacts using a novel method based on electrical capacitance, Submitted for the degree of PhD. Brunel University; 2011.
61.
LordJ, LarssonR.Effects of slide-roll ratio and lubricant properties on elastohydrodynamic lubrication film thickness and traction. Proc IMechE Part J Mech Eng Trib. 2001;215(3):301–308. doi: 10.1243/1350650011543556
62.
WestlakeFJ, CameronA.A study of ultra-thin lubricant film using an optical technique. Proc Inst Mech Eng. 1967-8;182(3G):75–78.
63.
ChaomleffelJP, DalmazG, VergneP.Experimental results and analytical film thickness predictions in EHD rolling point contacts. Tribol Int. 2007;40(10-12):1543–1552. doi: 10.1016/j.triboint.2007.02.005
64.
ChittendenRJ, DowsonD, DunnJF, A theoretical analysis of the isothermal elastohydrodyamic lubrication of concentrated contacts I: direction of lubricant entrainment coincident with the major axis of the contact ellipse. Proc R Soc London. 1985;A397:345–369.
65.
HookeCJ.An interpolation procedure for the minimum film thickness in point contacts. Proc IMechE Part C J Mech Eng Sci. 1990;204:199–206. doi: 10.1243/PIME_PROC_1990_204_095_02
