Nowadays, due to the more and more important environmental issues and strict emission regulations, the electric vehicles are becoming popular and appearing in each type of transport, also in the aircraft industry. In this field, light weight, compact size, high power, and efficiency are the major design aspects. These criteria cause higher power density, thus the losses generated by the active parts are concentrated in a smaller volume. To handle the high thermal load, heat has to be effectively removed. The aim of this article is to improve the air-cooling system of a radial flux electric motor with the help of computational fluid dynamics (CFD) simulation. The stator is cooled by a water jacket, and the rotor is cooled by air in the closed housing. Several closed concepts are examined, with the different rotor and housing geometry. During the simulations, motor with a full load at maximal rotating speed is modelled. The results are compared with the base motor in the aspects of the critical parts’ temperature, cooling performance, losses, weight, and manufacturability. More than 40 °C magnet temperature reduction can be reached with geometry modification on the housing
