Electrical Conductivity of New and Used Automatic Transmission Fluids

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.

• Record URL:
  • https://doi.org/10.4271/2016-01-2205
• Availability:
  • Find a library where document is available. Order URL: http://worldcat.org/issn/19463952
• Supplemental Notes:
  • Abstract reprinted with permission of SAE International.
• Authors:
  • McFadden, Chris
  • Hughes, Kevin
  • Raser, Lydia
  • Newcomb, Timothy
• Conference:
  • SAE 2016 International Powertrains, Fuels & Lubricants Meeting
  • Location: Baltimore Maryland, United States
  • Date: 2016-10-24 to 2016-10-26
• Publication Date: 2016-10-17

Language

• English

Media Info

• Media Type: Digital/other
• Features: Figures; References;
• Pagination: pp 519-526
• Serial:
  • SAE International Journal of Fuels and Lubricants
  • Volume: 9
  • Issue Number: 3
  • Publisher: SAE International
  • ISSN: 1946-3952
  • EISSN: 1946-3960
  • Serial URL: https://www.sae.org/publications/collections/content/E-JOURNAL-04/

Subject/Index Terms

• TRT Terms: Additives; Automatic transmissions; Electric drives; Electric vehicles; Electrical conductivity; Hybrid vehicles; Hydraulic fluids; Temperature
• Subject Areas: Energy; Highways; Materials; Vehicles and Equipment;

Filing Info

• Accession Number: 01771095
• Record Type: Publication
• Source Agency: SAE International
• Report/Paper Numbers: 2016-01-2205
• Files: TRIS, SAE
• Created Date: May 3 2021 11:48AM