A1 Journal article (refereed), original research

Performance of a Direct-Liquid-Cooled Motor in an Electric Bus Under Different Load Cycles

Open Access publication

Publication Details
Authors: Lindh Pia, Petrov Ilya, Immonen Paula, Pyrhönen Juha, Niemelä Markku, Anttila Joel, Paakkinen Marko, Scherman Eero
Publisher: Institute of Electrical and Electronics Engineers (IEEE): OAJ / IEEE
Publication year: 2019
Language: English
Related Journal or Series Information: IEEE Access
Volume number: 7
Start page: 86897
End page: 86905
Number of pages: 9
eISSN: 2169-3536
JUFO-Level of this publication: 2
Open Access: Open Access publication


In this paper, a direct liquid cooling method is proposed for a radial-flux permanent-magnet motor. To demonstrate the feasibility of the cooling method, a test motor with a rated output of 205 kW was designed, constructed, and tested in an actual vehicle application, an electric city bus. The energy consumption tests were conducted by applying a heavy-duty chassis dynamometer capable of simulating the inertia, weight, and road loads that the buses are subjected to in the normal on-road operation. The electricity consumption on the real bus route of the Espoo line 11 in Finland was 0.61 kWh/km. The test results of the cooling solution show that the motor is capable of meeting the most challenging requirements of the load cycle even with a full payload. The highest winding temperature rise in the test driving cycles was only 26 °C, which proves the effectiveness of direct-liquid-cooled coils in a vehicle motor.

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Last updated on 2020-20-03 at 10:03