Experimental investigation on rotational oscillating heat pipe for in-wheel motor cooling of urban electric vehicle

Abstract

To address the flexible functions and better driving experience of future urban electric vehicles, the wheel corner module (WCM) that integrates traction motors into each wheel has become a hotspot in recent years. Traditional cooling solutions of the motor generally used auxiliary cooling systems, which increase the cost of the WCM with multiple motors. It is necessary to cool each motor with low cost, good thermal performance solution and without auxiliary systems. A novel cooling solution based on a 3D rotational oscillating heat pipe (ROHP) is proposed, which depends on the gravity, centrifugal force and cooling air generated by motor rotation to ensure its thermal performance. The thermal performance is investigated experimentally. The result shows that the ROHP can operate normally under the extremely low rotation speed of 1 r/min. As the speed increases, the heat transfer performance is stable. Even at the maximum heating power of 300 W and the maximum speed of 450 r/min, the ROHP shows excellent thermal performance. The maximum temperature under the real driving cycles of the New European Driving Cycle and the World Light Duty Vehicle Test Cycle are 87.4 °C and 115.4 °C respectively, which are lower than the demagnetization temperature of 180 °C.