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High Quality Base Oils for Next Generation Automatic Transmission Fluids
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 19, 1998 by SAE International in United States
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Significant changes are occurring in the development of automatic transmission fluids (ATF) which impact the selection of both additive components and lubricant base oils. In particular, the need for improved viscometrics at high and low temperatures, combined with the need for increased oxidation performance and shear stability are moving formulators towards use of higher quality API Group II (100 - 120 VI) and/or Group III base oils.
Several benefits are apparent with the use of API Group III base oils in ATF. Their naturally high Viscosity Index of >120 provides opportunities to use a higher base oil viscosity compared to API Group I and in many instances Group II base oils. This reduces the amount of Viscosity Modifier in the finished ATF and improves overall shear stability. Higher kinematic viscosity also improves volatility which leads to improved oxidation resistance.
Low temperature fluidity can be improved by modifying the amount and type of residual wax in the base oil. This is achieved through two main factors, namely: (i) feed selection and (ii) the type of dewaxing process, isodewaxing being preferred to conventional solvent dewaxing. Finally, the higher concentration of saturated versus aromatic molecules in an API Group II and Group III base oil provide enhanced antioxidant response.
The relationship between base oil composition and ATF performance will be discussed in terms of low temperature Brookfield viscosity, shear stability and oxidation performance. Particular emphasis will be given to API Group II+ and Group III base oils produced by severe hydro-treating and isodewaxing.
CitationHenderson, H. and Swinney, B., "High Quality Base Oils for Next Generation Automatic Transmission Fluids," SAE Technical Paper 982666, 1998, https://doi.org/10.4271/982666.
- Powertrain Quarterly “Electronics Take Control” General Motors Powertrain Group Spring 1994
- Ward W.C. Copes R.G. “The Next ATF Challenge - Meeting Fuel Efficiency Needs and Providing Driver Satisfaction” NPRA Annual Meeting, AM-93-06 1993
- Watts R.F. Bloch R. “The Effect of Basestock Composition on Automatic Transmission Fluid Performance” NPRA Annual Meeting, FL-90- 118 990
- Watts R.F. Szykowski J.P. “Formulating Automatic Transmission Fluids with Improved Low Temperature Fluidity” SAE Paper No. 902144
- Papay A. G. “Formulating Automatic Transmission Fluids” Lubrication Engineering 47 4 271 275 1991
- Hamilton G.D.S. Lanthier R. Markin A.D. “Development of Automatic Transmission Fluids Having Excellent Low Temperature Viscometric and High Temperature Oxidative Properties” SAE Paper No. 902145
- Cornish C.W. Watts R.F. “Basestock Requirements of Evolving Automatic Transmission Fluid Specifications” NPRA Annual Meeting, AM-96-3 4 1996
- Bagnall R.A. Swinney B. “Significant Considerations in Selecting Base Stocks for Automatic Transmission Fluids” SAE Paper No. 821242
- Henderson H.E. Olavesen C. Alexander A.G. Ozubko R.S. “A New High Quality 100 Neutral Basestock for Automotive and Industrial Oil Products” Lubrication Engineering 48 10 777 781 1992
- MacAlpine G.A. May C.J. “Compositional Effects on the Low Temperature Pumpability of Engine Oils” SAE Paper No. 870404
- Wilson M.W. Eiden K.L. Mueller T.A. Case S.D. Kraft G.W. “Commercialization of Isodewaxing - A New Technology for Dewaxing to Manufacture High Quality Lube Base Stocks” NPRA Annual Meeting, FL-94-1 12 1994
- Baker C.L. McGuiness M.P. “Mobil Lube Dewaxing Technologies” NPRA Annual Meeting, AM-95-56 1995
- Andre J.P. Hahn S.K. Min W. “An Economical Route to High Quality Lubricants” NPRA Annual Meeting, AM-96-3 8 1996
- MERCON ® AND MERCON V ® are Ford Motor Company Engineering Material Specifications
- Mack P.D. Zaugg T.D. Cohen S.C. “Severely Hydro-Cracked/Hydro-Isomerized Base Oils - The Key to Enhanced Performance Levels” NPRA Annual Meeting, FL-96- 114 1996
- Henderson H.E. Cohen S.C. “Petro-Canada Base Oils Well Positioned for the 2 1 st Century” Canadian Chemical News 13 16 June 1997
- General Motors Engineering Standard GM 64 17-M
- Chrysler MS7 176E and MS9602 are Chrysler Engineering Material Specifications