Abstract
The aim of this study is to evaluate the performance and simulate road driving conditions of integrated powertrain cooling system, analyze the battery/inverter cooling system for hybrid electric vehicles(HEV). The prototype electric device’s radiator for powertrain(a motor and power conveter/inverter) cooling was fabricated and the performance was evaluated on the optimum test rig with the variation of coolant flow rate and air inlet velocity. Electric device’s cooling system, such as motor and inverter, needed to be maintained under 75℃ for thermal stability. Under the certain condition, which inlet temperature difference(ITD) between air and coolant is 20℃, optimum coolant flow rate for electric device’s radiator was 10 LPM with heat capacity, 3.5kW at air inlet velocity 4m/s. Moreover, road simulations with powertrain cooling system were performed by UH3D. Consequently, integrated condenser and electric device’s radiator was suitable to satisfy cooling performance in terms of vehicle layout under harsh cooling condition. The analysis of the battery/inverter cooling system has been peformed by applying the computational fluid dynamics (CFD) code to investigate fluid dynamic behavior characteristics and effectively design air flow rate of the system for hybrid electric vehicles (HEV). As a result, at design operating condition, air flow rate of the battery/inverter cooling system was 218.0 m3/h and the corresponding efficiency of the blower motor was predicted about 71.0%. Furthermore, for the battery/inverter cooling system, the average temperature of the battery was about 42.4°C.
Keywords: Hybrid electric vehicle, Electric device’s cooling system, Cooling performance, Battery/inverter cooling system, Computational fluid dynamics