Propulsion Thermal Management for Fuel Economy Improvement of Mild Hybrid Vehicles

Date of Award


Publication Type


Degree Name



Mechanical, Automotive, and Materials Engineering

First Advisor


Second Advisor

N.Van Englen

Third Advisor



Electric vehicles, Thermal management system, Low temperature recirculation loop



Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.


Over the years, reducing the emission pollutants coming from transportation vehicles has been one of the main targets. As a counter, vehicle manufacturers have been spending a lot of time in research and development for electric vehicles (EV) and hybrid electric vehicles (HEV). With the increased number of electronics, auxiliary components, design complexity and weight increase introduced to vehicles, the thermal management system (TMS) can be of great positive influence. The management system can target improvements in fuel economy, range, comfort, and safety. Its function consists of maintaining and controlling temperatures, pressures, and load ranges of the system. The focus of this thesis is to design three distinct cooling loops. The first loop is the high temperature cooling loop taking care of the engine cooling. The secondary loop takes care of the low temperature components and electronics. Lastly, the refrigerant loop which ensure drivers and passenger comfort was testing by implementing a cool down test and demonstrated the ability to follow real life results and by remaining in the set error ranges. After executing the analysis of the model, it has shown that the Low Temperature Recirculation Loop’s highest exergy destruction comes from the heat sink since the battery module has a loss of about 0.16 kW. Furthermore, having investigated the electrical pumps and fan, the state of charge of the battery from its initial charge percentage to shows close to a 20% reduction of change of power by maintaining the 80 W pump around 50% activation and 20W pump around 20% activation and remaining in desired component temperature ranges.