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ATF Friction Properties and Shift Quality
Technical Paper
2004-01-3027
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Multiple plate disk clutches are used extensively for shifting gears in automatic transmissions. In a shift from one gear to another one or more clutches is engaging or disengaging. In these active clutches the automatic transmission fluid (ATF) and friction material experience large changes in pressure P, temperature T, and sliding speed v. The coefficient of friction, μ, of the ATF and friction material depends on v, P and T, and also changes during clutch engagement. Changes in μ can lead to vibration and poor shift quality if the ATF and clutch friction material are improperly selected.
An in-depth theoretical understanding of the cause of vibration in shifting clutches is crucial in the development of a suitable ATF to work with a particular friction material. To understand the relationship between ATF friction properties and shifting clutch vibration we present a theoretical model that identifies several possible causes: (1) self-excitation instability, (2) a reduction in friction holding torque during engagement, or (3) resonance caused by periodic pressure oscillations.
The ATF and friction material properties that affect these sources of vibration include the friction level, μ, and the friction slopes with respect to sliding speed ∂μ/∂v, pressure ∂μ/∂P, and temperature ∂μ/∂T. These properties must be carefully balanced to ensure that a clutch will deliver good shift quality and high torque capacity with effective vibration suppression.
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Cameron, T., McCombs, T., Devlin, M., Tersigni, S. et al., "ATF Friction Properties and Shift Quality," SAE Technical Paper 2004-01-3027, 2004, https://doi.org/10.4271/2004-01-3027.Data Sets - Support Documents
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References
- Albers A. Herbst D. “Chatter - Causes and Solutions,” 6 th LuK Symposium 19-20 March 1998
- Cameron T. M. Tersigni S. H. McCombs T. Jao T.-C. “Effects of ATF Friction Properties on Shudder in Slipping Torque Converter Clutches,” Proceedings of the 14th International Colloquium on Tribology 12-15 January 2004 Esslingen Germany
- Cameron T. M. Jao T. C. Tersigni S. H. McCombs T. “ATF Friction Effects on Stability in Slip-Controlled Torque Converter Clutches,” SAE Powertrain & Fluid Systems Conference October 27-30 2003 Pittsburgh, PA Paper# 2003-01-3255
- Kotwicki A. “Dynamic Models for Torque Converter,” SAE Paper No. 820393 1982
- Hiramatsu T. Akagi T. Yoneda H. “Control Technology of Minimal Slip-Type Torque Converter Clutch” SAE Paper No. 850460
- Kugimiya T. Mitsui J. Yoshimura N. Kaneko H. Akamatsu H. Ueda F. Nakada T. Akiyama S. “Development of Automatic Transmission Fluid for Slip-Controlled Lock-up Clutch Systems” SAE Paper No. 952348 1995
- Luenberger D. G. Introduction to Dynamic Systems 1979 Wiley New York
- Palm W. J. III Modeling, Analysis, and Control of Dynamic Systems 2nd 2000 Wiley New York