Jun 29, 2020
Posted by Michael Gahagan, Technology Manager - Driveline
This article highlights the key takeaways from our recent Lubricants for e-Mobility webinar, part of our Lubrizol360 Webinar Series featuring Lubrizol experts discussing important industry trends. You can view the full webinar, and register for upcoming webinars here.
Hybrid electric vehicle technology is evolving at a rapid pace, and it’s vitally important that the fluid and lubricant additive technology keep up. Whether it’s in full-hybrid, plug-in hybrid, or all-electric vehicles, new hardware configurations have heightened demands for critical fluids and lubricants—and some of them are entirely new.
Following are some of these new demands:
Electrical interactivity. In an increasing amount of new hybrid designs, the e-motor and electronics can come into contact with the lubricant and, in some cases, may even be immersed in lubricant. Many e-motors are operating at higher and higher voltages in electrified vehicles, and for fluids and lubricants therefore, there is an increasing demand for lubricating fluid thermal management of the e-motor.
New materials. Electrified vehicles incorporate a large amount of copper and power electronics into their designs, along with new plastic materials used for insulation or to replace traditional metallic materials for lightweighting. Some of these materials have not been a part of traditional transmission architecture. For fluids and lubricants, this means new considerations around chemical compatibility with these materials in order to prevent issues like corrosion or degradation of the material.
Different temperatures. Lubricating fluids must account for different operational conditions in hybrid transmissions. For example, transmission temperature profiles differ from the traditional internal combustion engine (ICE) vehicle transmission operation, with localized temperature spikes occurring when there is a large sudden current draw on the e-motor. Dynamic viscosity, density, specific heat capacity and thermal and oxidative stability of fluids are all increasingly important attributes for these reasons.
New friction requirements. Noise, vibration and harshness (NVH) during operation is an increasingly important concern for manufacturers of electrified vehicles in order to provide a more satisfying experience for the driver. The right driveline fluid formulation can provide outstanding friction performance by designing beneficial friction behavior in components requiring friction to operate effectively, such as clutches immersed in the lubricating fluid. Unsuitably-designed transmission fluid, can generate clutch shuddering, gear and bearing vibration.
Lower viscosities. For the same reason that lower-viscosity lubricants have become more popular in traditional transmissions, the same is happening in the world of electric vehicles. Thinner fluids generate less resistance to moving mechanical parts, therefore leading to more efficient operation. Formulations of fluids and lubricants for electric applications must balance this demand with all others.
EVs need different lubricants. Hardware efficiency and durability in a growing number of applications are best enabled by specialized, custom fluids designed and formulated specifically for electric applications. New lubricant and fluid technology must deliver:
- Proper electrical characteristics
- Superior corrosion protection
- Suitable thermal management
- Compatibility with new plastics
- Smooth friction performance for NVH benefits
For more information on the evolving needs of hybrid and electric vehicles, contact your Lubrizol representative, and watch the full in-depth webinar on lubricants for e-mobility here.