Clemens Schlegel
Schlegel Simulation GmbH, Freising, Germany
Andreas Hösl
BMW Group, Munich, Germany
Sergej Diel
University of Applied Sciences Landshut, Landshut, Germany
Download article
http://dx.doi.org/10.3384/ecp09430059Published in: Proceedings of the 7th International Modelica Conference; Como; Italy; 20-22 September 2009
Linköping Electronic Conference Proceedings 43:48, p. 434-443
Published: 2009-12-29
ISBN: 978-91-7393-513-5
ISSN: 1650-3686 (print), 1650-3740 (online)
Drag torques of gearboxes are an important part of the overall losses in today’s vehicle drive trains. From measurements it is well known that overall drag torques of vehicle gearboxes vary significantly over the range of operating points and speeds; depending on the interaction of the losses of the single gearbox elements like bearings; gearings; etc. Because today’s vehicle emission regulations are becoming stricter and stricter "drag torque design" of gearboxes will be even more important in the future. Prediction of losses helps to save cost (e.g. drag torque measurements); speeds up the development and allows to assess many concepts in short time.
We collected detailed semi-analytical drag models for the common gearbox components from literature and from manufacturer information and implemented them in a Modelica library. This library contains models for radial shaft seals; rotary unions; synchronizers; multi-disc clutches; helical gearings; planetary gearings; various kinds of bearings; lubrication systems and lubricant characteristics. Using this library drag torques of any vehicle gearbox may be computed for any operating condition (engaged gear;
speed; torque; temperature). Simulation results for a 7 speed double clutch transmission show good correlation with measurements.
