Globally, the demand of eco-friendly cars is increasing, and various researches on the electric vehicles are being conducted. Different from internal combustion engines, thermal management system of electric vehicle adopts electric water pump. Since the lifespan of battery is very sensitive to very narrow temperature band, cooling system provides key solutions. Electric water pump is core component of cooling system which satisfies performance and durability criteria. Since, local hot spot of motor casing results in degradation of motor lifespan, it is necessary to design motor casing for effective heat rejection. In this study, two different motor casing designs are applied to reject joule heating of motor efficiently. The temperature distribution of each casing is investigated with the IR camera. The IR camera was used to identify the local hot spot where the heat was most generated in the pump. Since the joule heating is proportional to pump power, it is necessary to understand the operating characteristics of electric water pump. Experimental apparatus includes water reservoir, bypass valve, pressure and temperature sensors, DAQ and IR camera. The water reservoir is included the heating rod to control the temperature. First, the IR camera was used to identify the portion where the heat was most generated in the pump. Afterwards, the temperature of the pump was analyzed to determine the steady state time. Through the experiment, it was found that the temperature reached the steady state after about 1 hour, and it showed a temperature up to 55 degrees. To check the degree of heat generation the pump temperature and performance for the presence or absence of the motor casing was analyzed. Also, the pump performance curve and max temperature at 2500, 3000, 3500, 4000 rpm was compared and analyzed. Afterwards, experiments were conducted by adjusting the flow rate and the internal water temperature in order to obtain the external temperature distribution at various motor loads. The external temperature of the pump was determined when the flow load was increased from 0 to 100 at 10% intervals. The external temperature of the pump was measured when the internal water temperature was increased from ordinary temperature to 30 degrees at the 10 degree intervals. As a result, the local hot spot is strongly depended to pump load and it is mainly observed near cable connector. Since the temperature distribution on the casing surface is also affected by the local hot spot, it is necessary to optimize heat rejection by extended surface.


Local Hot Spots of Electric Water Pump Casing Over Various Pumping Loads

Division / Sponsors: 
Aerospace, Bioengineering, Applied Mechanics, Design Engineering Division, Advanced Energy Systems, Manufacturing Engineering Division, Noise Control and Acoustics, Nondestructive Evaluation, Diagnosis, and Prognosis (NDPD), Nuclear Engineering Division, Process Industries Division, Fluids Engineering, Heat Transfer, Materials, Microelectromechanical Systems, Safety Engineering and Risk Analysis, Computers & Information in Engineering


Paper Proceedings: https://asmedigitalcollection.asme.org/IMECE/IMECE2020/volume/84478

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