Abstract
Thermal management of a junction box of a passenger car has recently become more challenging due to its smaller size and larger current capacity. Thus, it is essential to perform the thermal optimization of a junction box in its design on an early stage of vehicle design. In this study, 3 dimensional CFD simulation with experimental measurement has been done to study for better thermal management of the junction box. First, the study of thermal characteristics of electric relays in the junction box has revealed that each surface of the relay has very different thermal resistance. In addition, an idea to install a cooling fan on the junction box has been studied and it was found that the forced cooling method was not effective on the system to keep the thermal resistance to the reasonable level of the junction box. Finally, the effect of external flows around the junction box on the temperatures of the relays, fuses, etc. has been studied and the result shows that the installation of the junction box at the proper place in an engine room can avoid any unnecessary overdesign in thermal management.
