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Wet Clutch Drag Loss Simulation for Different Clutch Patterns
Technical Paper
2022-01-1118
ISSN: 0148-7191, e-ISSN: 2688-3627
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English
Abstract
Wet clutches drag loss simulation is essentially linked to the clutch friction surface patterns in addition to the main geometry and conditions of the interface (relative speed, separation, inner and outer radius, viscosity and boundary pressures). The clutch patterns promote cooling flow and micro-hydrodynamic effects to aid clutch separation but greatly complicate the simulation of drag loss during separation. These drag losses are important in understanding the system losses as well as finding the most effective clutch cooling strategy. Typical clutch models either only consider simple patterns, such as radial grooves, or require significant simulation efforts to evaluate. Additionally, many simple models require calibration to measurement of the actual clutch they try to model before they provide a useful model.
A methodology utilizing smooth particle CFD (PreonLab) will be demonstrated to provide a fast and effective solution to any given clutch pattern, capturing the fundamental viscous drag region and film rupture point and subsequent reducing curve and the operating temperature effect on drag losses. A post-processing solution will be shown in which a segment of the overall clutch interface area is discretized, and surface wetted area is extracted to allow a calculation of the resulting lubricant shear stresses. The methodology easily compliments other simulation for the flow rate and distribution of lubricant in single or dual wet clutch packs within transmission systems. It will be shown that the proposed method provides reasonable results in comparison to literature and existing analytical models of simple clutch geometry.
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Citation
Szalai, G., Ray, R., Bansal, H., and Leighton PhD, M., "Wet Clutch Drag Loss Simulation for Different Clutch Patterns," SAE Technical Paper 2022-01-1118, 2022, https://doi.org/10.4271/2022-01-1118.Also In
References
- Fischer , R. , Küçükay , F. , Jürgens , G. , Najork , R. et al. The Automotive Transmission Book Springer 2015 10.1007/978-3-319-05263-2
- Crolla , D. Automotive Engineering - Powertrain, Chassis, System and Vehicle Body Butterworth-Heinemann 2009 ISBN: 978-1-85617-577-7
- Rahnejat , H. Tribology and Dynamics of Engine and Powertrain - Fundamentals, Applications and Future Trends Woodhead publishing 2010 978-1-84569-993-2
- Ribbens , W. Understanding Automotive Electronics - An Engineering Perspective Butterworth-Heinemann 2017 ISBN: 978-0-12-810434-7
- Chen , Y. Automotive Transmissions; Design, Theory and Applications Springer 2021 10.1007/978-981-15-6703-2
- Morris , N. , Patel , R. , and Rahnejat , H. Hydrodynamic Lubricant Film Separation During Codirectional and Counter-Directional Rotations of Disengaged Wet Clutch Packs Journal of Fluids Engineering 2019 10.1115/1.4044443
- Morris , N. , Davies , J. , Leighton , M. , King , P. et al. Oil Film Separation and Drag Torque in Disengaged Wet Brakes Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering 2019 10.1177/0954407019844358
- Leighton , M. , Morris , N. , Trimmer , G. , King , P. et al. Efficiency of Disengaged Wet Brake Packs Proceedings of the Institution of Mechanical Engineers Part D Journal of Automobile Engineering 2018 10.1177/0954407018758567
- Leighton , M. , Davies , J. , Morris , N. , Rahnejat , H. and Trimmer , G. 2017
- Leighton , M. , Morris , N. , Rahmani , R. , et al. A Combined Numerical and Experimental Investigation of Disengaged Wet Brake Plate Power Loss 3rd Biennial International Conference on Powertrain Modelling and Control (PMC) 2016
- Humphrey , E. , Gkinis , T. , Morris , N. , et al. Clutch Lining Frictional Characteristics under Thermal Tribodynamic Conditions 3rd Biennial International Conference on Powertrain Modelling and Control (PMC) 2016
- AVL n.d. https://www.avl.com/fifty2-preonlab
- Halling , J. Introduction to Tribology Wykeham Publications 1976 ISBN 0 85109 061 3
- Thomas , N. , Elisabeth , B. , and Dirk , B. Parameter Study on the Influence of a Radial Groove Design on the Drag Torque of Wet Clutch Discs in Comparison with Analytical Models Tribology International 2018 10.1016/j.triboint.2017.12.005
- Dowson , D. Inertia Effects in Hydrostatic Thrust Bearings Journal of Basic Engineering 83 2 1961 227 234 10.1115/1.3658931
- Thomas , N. and Dirk , B. High-resolution 3D CFD Multiphase Simulation of the Flow and the Drag Torque of Wet Clutch Discs Considering Free Surfaces Tribology International 129 January 2019 283 296 10.1016/j.triboint.2018.08.031
- Liu , H. Numerical Modelling of Oil Distribution and Churning Gear Power Losses of Gearboxes by Smoothed Particle Hydrodynamics Proc IMechE Part J: J Engineering Tribology 233 1 2019 74 86 10.1177/1350650118760626
- Zhang , C. , Zhu , Y. , Wu , D. , and Hu , X.