This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Shifting from Automatic to Continuously Variable Transmissions: A Look at Fluid Technology Requirements
ISSN: 0148-7191, e-ISSN: 2688-3627
Published October 25, 1999 by SAE International in United States
Annotation ability available
New technologies are being commercialized across the automotive industry to address demands for improved fuel economy, emissions reductions, and improved customer satisfaction. Push-belt continuously variable transmissions (b-CVTs) are beginning to command a significant percentage of the market now dominated by manual and conventional automatic transmissions. In addition, automobile manufacturers plan to introduce the first traction drive toroidal-CVTs to the market place within the next five years. A review of the relative benefits and limitations of each of these automatic transmissions exists in the literature. In this paper we consider how the performance requirements of each of these automatic transmission systems impact automatic transmission fluid technology.
The physical characteristics and screen test performance of two commercial ATFs, a b-CVTF, and two traction fluids were examined. The overall performance characteristics of the b-CVT fluid were comparable to that of a modern ATF illustrating the evolutionary relationship betweenATF and b-CVTF technology. Commercial traction fluids had poor wet clutch and low temperature performance while the commercial ATFs and b-CVTF had low traction coefficients. This illustrates the separate paths on which these fluid technologies were developed. Lastly, results from two experimental fluids suggest that it may be possible to formulate a traction fluid for automotive use that exhibits wet clutch friction stability without significantly compromising traction performance.
- Michael E. Huston - The Lubrizol Corporation
- Craig D. Tipton - The Lubrizol Corporation
- Farrukh Qureshi - The Lubrizol Corporation
- James L. Sumiejski - The Lubrizol Corporation
- Thomas S. Derevjanik - The Lubrizol Corporation
- Christopher A. Flask - The Lubrizol Corporation
- David J. Whitticar - The Lubrizol Corporation
- William C. Ward - The Lubrizol Corporation
CitationHuston, M., Tipton, C., Qureshi, F., Sumiejski, J. et al., "Shifting from Automatic to Continuously Variable Transmissions: A Look at Fluid Technology Requirements," SAE Technical Paper 1999-01-3614, 1999, https://doi.org/10.4271/1999-01-3614.
SAE 1999 Transactions - Journal of Fuels and Lubricants
Number: V108-4; Published: 2000-09-15
Number: V108-4; Published: 2000-09-15
- Willermet P. A. “Topics in Transmission Tribology” Journal of the Society of Tribologists and Lubrication Engineers February 1999 39 43
- Kemp S. P. Linden J. L. “Physical and Chemical Properties of a Typical Automatic Transmission Fluid” SAE Paper 902148 1990 Skrobul A. P. Megnin L. L. “Automatic Transmission Fluids - A Primer” LUBRICATION 81 1 1995
- DEXRON®-III Automatic Transmission Fluid Specification April 1993 MERCON® Automatic transmission Fluid Specification Ford Motor Company, Livonia Transmission Product Engineering Livonia, MI, 48151 1992
- Watts, R. F. Richard, K. M. “CVT Lubrication: The Effect of Lubricants on the Frictional Characteristics of the Belt-Pulley Interface”” Fifth CEC International Symposium on the Performance Evaluation of Automotive Fuels and Lubricants May 13-15 1997 Goteborg, Sweden
- Ishikawa, T. Murakami, Y. Yauchibara, R. Sano, A. “The Effect of Belt-Drive CVT Fluid on the Friction Coefficient Between Metal Componenets” SAE Paper # 972921 Ward, W. C. Jr. Sumiejski, J. L. Derevjanik, T. S. Fewkes, R. Ikeda, M. “Belt Drive CVT Fluid Evaluation” '98 International Symposium of Tribology of Vehicle Transmissions February 4-6 1998
- The history of Torotrak Torotrak Sales Literature
- Winer, W.O. Cheng, H.S. “Film Thickness, Contact Stress and Surface Temperatures,” Wear Control Handbook Peterson, M.B. Winer, W.O. ASME 1981 81 141
- Bair, S. Winer, W. O. “Regimes of Traction in Concentrated Contact Lubrication,” Transactions of ASME, Journal of Lubrication Technology 104 July 1982 382 386
- Tipton, C. D. Schiferl, E. A. “Fundamental Studies on ATF Friction SAE 971621 Tipton, C. D. M. E. Wetsel, W. R. “Fundamental Studies on ATF Friction SAE 982670