Design of an FSAE Cooling System for Electric In-hub Motors

Abstract

This thesis explores the design of water cooled electric in-hub motors for use in high power automotive applications such as Formula SAE Electric student racecars. The main components of the drivetrain of the 4WD electric vehicle are the motor and the motor controller. This thesis focuses on designing a reliable cooling system for the motors to ensure that they operate in an optimal temperature range that increases drivetrain efficiency, prevents catastrophic motor damage, and ultimately improves vehicle performance.

During the design process, extensive heat transfer analysis was conducted for liquid cooling, air cooling, and heat pipes. Additionally, CFD was conducted for various water cooling architectures to determine the influence of coolant flow direction and channel dimensions on cooling performance. Results were subsequently analyzed, plotted, and used in the motor cooling architecture selection process.

After determining the motor cooling sleeve architecture and dimensions, detailed CAD was created for both plastic prototype sleeves as well as metal 3D printed sleeves. Testing demonstrated that the cooling sleeve successfully met its target pressure drop of 3-4PSI. More thorough testing and data collection of the cooling sleeve’s thermal performance is still in progress. While details on the CAD, prototyping, testing & validation, and manufacturing, are outside the scope of this thesis, images are included for reference.