This content is not included in your SAE MOBILUS subscription, or you are not logged in.
Understanding Base Oils and Lubricants for Electric Drivetrain Applications
ISSN: 0148-7191, e-ISSN: 2688-3627
Published December 19, 2019 by SAE International in United States
This content contains downloadable datasetsAnnotation ability available
The penetration of hybridization and electrification (HEV and EV) technology into automotive powertrain designs is an evolving trend resulting from global regulations intended to reduce transportation-related emissions of greenhouse gases and other pollutants and to improve vehicle fuel efficiency. In many HEV and EV hardware designs, drivetrain fluids have contact with the integrated electric motor (e-motor), which requires electrical and thermal properties to be considered in addition to traditional fluid properties.
This paper discusses new insights gained around electrical and thermal properties of drivetrain fluids, with a specific emphasis on understanding the critical impacts of base oils (BOs). Electrical and thermal properties data as a function of temperature for a range of BOs as well as automatic transmission fluids are shared. We found that BOs and their viscosities play a critical role in cooling performance, while additives play a critical role in electrical conductivity (EC). That being said, we also have observed that additives in BOs can modify cooling performance. We will demonstrate how each component in the additive package affects EC and in some cases cooling performance. The successful utilization of this knowledge is demonstrated on a proof-of-principle basis to show that fluids with appropriate electrical and thermal properties can be designed to meet critical factors for electrification such as cooling capacity and EC, while still maintaining essential performance features for conventional driveline fluids.
- Yungwan Kwak - Afton Chemical Corporation, Richmond, Virginia 23219, USA
- Christopher Cleveland - Afton Chemical Corporation, Richmond, Virginia 23219, USA
- Atanu Adhvaryu - Afton Chemical Corporation, Richmond, Virginia 23219, USA
- Xinggao Fang - Afton Chemical Corporation, Richmond, Virginia 23219, USA
- Susie Hurley - Afton Chemical Limited, Bracknell, UK
- Tsuneo Adachi - Afton Chemical Japan Corporation, Tokyo, Japan
CitationKwak, Y., Cleveland, C., Adhvaryu, A., Fang, X. et al., "Understanding Base Oils and Lubricants for Electric Drivetrain Applications," SAE Technical Paper 2019-01-2337, 2019.
Data Sets - Support Documents
|[Unnamed Dataset 1]|
|[Unnamed Dataset 2]|
- Tang, T., Devlin, M., Mathur, N. et al., “Lubricants for (Hybrid) Electric Transmissions,” SAE Int. J. Fuels Lubr. 6(2):289-294, 2013, doi:10.4271/2013-01-0298.
- Huang, Z., Nategh, S., Lassila. V. et al., “Direct oil cooling of traction motors in hybrid drives,” 2012 IEEE International Electric Vehicle Conference, Greenville, SC, 2012, pp. 1-8. doi:10.1109/IEVC.2012.6183163.
- Mouromtseff, I.E., “Water and Forced Air Cooling of Vacuum Tubes,” Proceedings of the IRE, Vol. 30(4), pp. 190-205, 1942.
- Tsubochi, T., Deshimaru, J., “Research and development of cooling and lubricating oils for HEV/EV motors,” JSAE Pre-Symposium Proceedings, No. 155-10, 2010.
- Bennion, K., Moreno, G., “Convective Heat Transfer Coefficients of Automatic Transmission Fluid Jets with Implications for Electric Machine Thermal Management,” Preprint, 2015 InterPACK, San Francisco, California, 2015.
- “Standard Test Method for Thermal Conductivity, Thermal Diffusivity and Volumetric Heat Capacity of Engine Coolants and Related Fluids by Transient Hot Wire Liquid Thermal Conductivity Method,” ASTM D7896, Published June 2014, DOI:10.1520/D7896-14.
- “Standard Test Method for Kinematic Viscosity of Transparent and Opaque Liquids (and Calculation of Dynamic Viscosity),” ASTM D445, Published November 2018, DOI:10.1520/D0445-18.
- “Standard Test Method for Electrical Conductivity of Liquid Hydrocarbons by Precision Meter,” ASTM D4308, Published July 2013, DOI:10.1520/D4308-13.
- API 1509, Appendix E, Section E.1.3.
- Daisuke, T., Keiich, N., “Lubricants technology for improving the performance in automatic transmission,” Journal of Society of Automotive Engineers of Japan, Vol 71 (11), 2017.
- McFadden, C., Hughes, K., Raser, L. et al., “Electrical Conductivity of New and Used Automatic Transmission Fluids,” SAE Int. J. Fuels Lubr. 9(3):2016, doi:10.4271/2016-01-2205
- Abedian, B., Baker, K. N., “Temperature effects on the electrical conductivity of dielectric liquids,” IEEE Trans. On Dielectrics and Dielectric Insulation 15(3): 888-892, 2008.