Low and High Temperature Non-Newtonian Behavior of Automatic Transmission Fluids 2002-01-1695
Rheological properties of automatic transmission fluids (ATFs) are typically characterized by their kinematic (ASTM D 445) and Brookfield (ASTM D 2983) viscosities. However, ATFs contain polymeric viscosity modifiers, which often result in non-Newtonian fluid behavior as the polymers align and stretch under the shear stresses experienced in automatic transmissions. Therefore, the standard rheological tests, which are normally run under low shear stresses, may not adequately characterize an ATF's flow properties under the operating conditions of the automatic transmission. This study was designed to characterize the rheological properties of ATFs containing different amounts of viscosity modifiers, different base oil types and different levels of permanent shear stability under the shear and temperature conditions which exist in automatic transmissions. The results indicate that fluids with the same kinematic and Brookfield viscosities can have viscosities under typical transmission operating conditions that differ by as much as 40%.
Citation: Sarkar, R., Devlin, M., Li, S., Glasgow, M. et al., "Low and High Temperature Non-Newtonian Behavior of Automatic Transmission Fluids," SAE Technical Paper 2002-01-1695, 2002, https://doi.org/10.4271/2002-01-1695. Download Citation
Author(s):
Reuben Sarkar, Mark T. Devlin, Shoutian Li, Michael B. Glasgow, Tze-Chi Jao
Affiliated:
General Motors Powertrain, Ethyl Petroleum Additives Inc.
Pages: 15
Event:
Spring Fuels & Lubricants Meeting & Exhibition
ISSN:
0148-7191
e-ISSN:
2688-3627
Related Topics:
Automatic transmissions
Transmission fluids
Transmissions
SAE MOBILUS
Subscribers can view annotate, and download all of SAE's content.
Learn More »