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Lubricants Formulation Technology for Fuel Saving Performance in Automatic Transmissions
ISSN: 0148-7191, e-ISSN: 2688-3627
Published September 01, 2015 by SAE International in United States
Annotation ability available
The use of Automatic Transmission Fluids (ATFs) with lower viscosity and excellent anti-shudder durability for wet clutch system will be effective for improving fuel saving performance in automatic transmissions. In this study, two ATF formulation techniques were examined. The first trial formulation is to improve fatigue life in gear components even if a lower viscosity ATF is used. The second one is to improve anti-shudder durability for wet lock-up clutch system in AT units. As to fatigue life performance, the relation between molecular weight of Viscosity Index Improver (VII) and film formation property in EHL contact regions were experimentally investigated. ATFs containing VIIs with lower molecular weight tend to increasing EHL film thickness, resulting in a longer gear pitting fatigue life. Calcium detergents and ashless friction modifiers in ATFs were found to give a great impact on the anti-shudder performance. The trial ATF containing these additives demonstrated 1.5 times longer anti-shudder durability compared with a commercial ATF.
|Technical Paper||Friction and Stick-Slip Durability Testing of ATF|
|Technical Paper||A New Automatic Transmission Fluid with Extended Friction Durability and Minimal Temperature Dependence|
CitationYokomizo, M., Iwai, T., Narita, K., and Kudo, M., "Lubricants Formulation Technology for Fuel Saving Performance in Automatic Transmissions," SAE Technical Paper 2015-01-2037, 2015, https://doi.org/10.4271/2015-01-2037.
- Yamamori K. , saitou K. , Kobiki Y. and Ogawa A. Study of Viscosity Index Improver for Fuel Economy ATF SAE Paper 2003-01-3258
- Kurosawa O. , Matsui S. , Komiya K. , Morita E. and Kawasaki Y. Development of New Automatic Transmission Fluid for Fuel Economy SAE Paper 2003-01-3257
- Umamori N. and kugimiya T. Study of Low Viscosity Index Improver for Fuel Economy ATF SAE Paper 2003-01-3256
- Fujita H. , Takakura Y. and Ikeda T. Study of Low Viscosity ATF with Extending Gear Fatigue Life 2007 JSAE/SAE International Fuels and Lubricants Meeting Kyoto 2007
- Jonston G. J. , Wayte R. and Spikes H. A. The measurement and study of very thin lubricant films in concentrated contacts Tribology Transactions 1991 187 194
- Kugimiya T. , Yoshimura N. , Kuribayashi T. , and Mitsui J. Tribology of automatic transmission fluid Tribology Letters 5 1998 49 56
- Jafri , F. , Fuß , M. , Bailey , G. , Kao , C. et al. Shudder Durability of a Wet Launch Clutch Part I - Thermal Study and Development of Durability Test Profile SAE Technical Paper 2009-01-0329 2009 10.4271/2009-01-0329