Electrical Conductivity of New and Used Automatic Transmission Fluids 2016-01-2205
Hybrid drivetrain hardware combines an electric motor and a transmission, gear box, or hydraulic unit. With many hybrid electric vehicle (HEV) hardware designs the transmission fluid is in contact with the electric motor. Some OEMs and tier suppliers have concerns about the electrical properties of automatic transmission fluids (ATFs). Lubrizol has conducted a fundamental research project to better understand the electrical conductivity of ATFs. In this paper, we will present conductivity data as a function of temperature for a range of commercially available ATFs. All fluids had conductivities ranging from 0.9 to 8x10-9 S/cm at 100 °C and can be considered insulators with the ability to dissipate static charge. Next we will deconstruct one ATF to show the relative impact of the various classes of lubricant additives. We find that more polar additives have a larger effect on conductivity on a normalized (per weight %) basis. Finally, we will show conductivity data for ATFs taken from field trial vehicles and present data to demonstrate that the increase in conductivity is due to oil oxidation and a reduction in viscosity, not the presence of metallic wear particles or dissolved metals.
Citation: McFadden, C., Hughes, K., Raser, L., and Newcomb, T., "Electrical Conductivity of New and Used Automatic Transmission Fluids," SAE Int. J. Fuels Lubr. 9(3):519-526, 2016, https://doi.org/10.4271/2016-01-2205. Download Citation
Author(s):
Chris McFadden, Kevin Hughes, Lydia Raser, Timothy Newcomb
Affiliated:
Lubrizol Corporation (The)
Event:
SAE 2016 International Powertrains, Fuels & Lubricants Meeting
ISSN:
1946-3952
e-ISSN:
1946-3960
Also in:
SAE International Journal of Fuels and Lubricants-V126-4, SAE International Journal of Fuels and Lubricants-V125-4, SAE International Journal of Fuels and Lubricants-V125-4EJ
Related Topics:
Transmission fluids
Hybrid electric vehicles
Automatic transmissions
Conductivity
Electric motors
Lubricant additives
Wear
Transmissions
Corrosion
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