The Effectiveness of Esters in Cooling and Lubricating Transmission Systems in Electric Vehicles-Dielectric Fluids

Energy conservation and emissions reduction have become increasingly significant for automobiles due to high energy demand, fuel economy and environmental concerns. Hybrid
Electric Vehicle (HEV) technology and fully Electric Vehicles (EV) are one of the most promising solutions offering a much lower fuel consumption and considerably low emissions. Emerging new driveline configurations bring new challenges in developments of HEV/EV fluids. Many different configurations have been conceived which use different methods of cooling and lubrication. Not only are these fluids essentials for lubricating and cooling the new types of powertrains and transmissions, but they are also needed to regulate the temperature of the vehicle's battery and power electronics. As hybrids and EVs become increasingly powerful and their battery ranges and charging speeds improve, standard fluids are unable to keep up in terms of robustness, heat resistance and cooling capacity. These conditions could be controlled by base fluid or advanced additive technology.
New technical constraints for the electrification of vehicles require the development of new
fluids with long lasting dielectric properties in harsh operating conditions such as high
temperatures, oxidation, humidity and particle abrasion. The fluid should also be compatible
with components of the electric/hybrid vehicles such as copper as key component in electrical wiring. In addition, the fluid needs to have an excellent thermal properties to cool the high heat generation in electric motor often exceeding 180oC. Last but not least, the fluid needs to fulfil the standard lubrication properties to reduce friction, wear, oxidation and corrosion in mechanical parts.
The overall aim of the project is to investigate the thermal properties of esters and how they
could be used to both cool and lubricate areas such as gears and electric motors used in
hybrid and fully electric vehicles. It is also possible that they could be used to cool sensitive
components such as electronics, regulating temperature and allowing better efficiency.
The specific objectives are:
- To assess thermal properties of Easters by rigorous numerical and experimental studies.
- To investigate the tribological and tribochemical performance of Easters in lubricating electric transmission systems.

The relationship with Croda has been established since 2016 and maintained over the past few years with one ongoing CDT project sponsored by them at present. The proposed project could further cement the ongoing relationship between the two and the proposed research sits across several EPSRC Research priority areas including End-Use Energy Demand, Surface Science, Advanced materials engineering, 21st Century Products and Materials for Energy Applications and thus could lead to new lines of research.