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Cooling effect of oil cooling method on electric vehicle motors with hairpin winding

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Abstract

The cooling effect of oil cooling method on electric vehicle motors with hairpin winding is analyzed. A 160 kW motor being developed by a commercial vehicle company is applied. Firstly, the flow field of oil was analyzed. In the crown part, 96% of the oil flowed; in the welded part, 90% of the oil flowed. Secondly, an analysis of the heat transfer in the coil and stator was performed. The welded part of the coil exhibited an average temperature 4% higher than that of the crown part. Finally, the parametric study was conducted to understand the effect of the temperature and flow rate of the oil on the temperature distributions of the motor. As the flow rate increases, the maximum temperature decreases. However, there is not a big difference at more than 0.8 LPM/LPM. The results provide important information for understanding the effect of a motor using oil cooling.

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Abbreviations

p :

Density [kg/m3]

V :

Continuum velocity [m/s]

f b :

Body force per unit volume acting on the continuum [W/m3]

p :

Pressure [Pa]

T 1 :

Viscous stress tensor [kg/m2]

E :

Total energy per unit mass [J/kg]

q :

Heat flux [W/m2]

S E :

Energy source per unit volume [W/m3]

μ t :

Turbulent viscosity [kg/m s]

T 2 :

Turbulent time scale [s]

\(\overline V \) :

Average velocity [m/s]

μ :

Dynamic viscosity [kg/m s]

T* :

Normalized temperature

V* :

Normalized velocity

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Acknowledgments

This research was supported by the Chung-Ang University Research Scholarship Grants in 2019. The support received from the Hyundai Mobis Co. is also greatly appreciated.

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Author notes

  1. These authors equally contributed to this work as first author.

Authors and Affiliations

  1. School of Mechanical Engineering, Chung-Ang University, Seoul, 06974, Korea

    Taewook Ha, Yerim Kang, Dong Kyu Kim & Hong Sun Ryou

  2. Hyundai Mobis, Gyenonggi, 16891, Korea

    Nam Seok Kim, So Hee Park & Sang Han Lee

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  1. Taewook Ha
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  2. Yerim Kang
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  4. So Hee Park
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  5. Sang Han Lee
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  7. Hong Sun Ryou
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Corresponding authors

Correspondence to Dong Kyu Kim or Hong Sun Ryou.

Additional information

Taewook Ha obtained his B.S. and M.S. degrees in Mechanical Engineering from Chung-Ang University, Seoul, South Korea. His research interests include thermo-dynamics and cooling of electric vehicle motors.

Yerim Kang obtained her B.S. and M.S. degrees in Mechanical Engineering from Chung-Ang University, Seoul, South Korea. Her research interests include thermo-dynamics and cooling of electric vehicle motors.

Nam Seok Kim is a Mechanical engineer at the Hyundai Mobis Technical Center, Yongin, Gyeonggi, South Korea. He is in charge of the structural design and package layout design of traction motors for the electric vehicle.

So Hee Park is a Mechanical engineer at the Hyundai Mobis Technical Center, Yongin, Gyeonggi, South Korea. She is in charge of NVH analysis and gear drive unit design of traction motors for the electric vehicle.

Sang Han Lee is a Mechanical engineer at the Hyundai Mobis Technical Center, Yongin, Gyeonggi, South Korea. He is in charge of the structural design of traction motors for the electric vehicle as a team leader.

Hong Sun Ryou is a Professor at the Department of Mechanical Engineering, Chung-Ang University, Seoul, Korea. His research interests are fluid dynamics, fire dynamics, evacuation and pedestrian dynamics, bio-medical eng.

Dong Kyu Kim is a Professor at the Department of Mechanical Engineering, Chung-Ang University, Seoul, Korea. His research interests include thermodynamics and polymer electrolyte membrane fuel cell, and fuel cell vehicle.

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Ha, T., Kang, Y., Kim, N.S. et al. Cooling effect of oil cooling method on electric vehicle motors with hairpin winding. J Mech Sci Technol 35, 407–415 (2021). https://doi.org/10.1007/s12206-020-1240-y

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  • DOI: https://doi.org/10.1007/s12206-020-1240-y

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