Onishi, Y., Ramsay, T., Juan, T., and McKillen, J., "The Thermal and Aerodynamic Development of a Cooling and Heat Resistance Package for a New Hybrid Sports Car," SAE Int. J. Passeng. Cars - Mech. Syst. 8(1):155-164, 2015, doi:10.4271/2015-01-1526.
A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept. The experimental and computational developments of ten air cooled-heat exchangers are described with the tradeoffs that were required during the development process. Since the cooling and heat resistance package was being developed as the vehicle concept and styling were coming together, CFD played a large role in the heat exchanger size, location, heat resistance package and performance. Specific correlation tests were conducted to gain a greater understanding of the performance of some of the heat exchangers. Ultimately, the flow through all of the heat exchangers was confirmed as meeting all the targets at the first wind tunnel test and also heat resistance package was fixed with significant CFD support.