Title: A model based approach for the optimisation of gearshifting in automatic transmissions

Authors: A. Haj-Fraj, F. Pfeiffer

Addresses: Institute of Applied Mechanics, Technische Universitat Munchen, 85748 Garching, Germany. Institute of Applied Mechanics, Technische Universitat Munchen, 85748 Garching, Germany

Abstract: In this paper, an approach for the optimisation of gear shift operations in automatic transmissions based on a verified mechanical model for a powertrain is presented. The control data for the clutch pressure in the gearbox and the engine load-reduction are used as optimisation parameters. The objective of the optimisation is to determine an optimal set of control data, so that the performance of the automatic transmission with respect to passengers comfort and gear shift duration is improved. Two sets of optimisation criteria are developed. The first one consists of three different cost functions for the description of the passengers comfort, whereas the second one contains two cost functions for the evaluation for the evaluation of the operating life of the shift elements. The nonlinear optimisation problem is solved with a sequential quadratic programming algorithm. The results show a significant improvement in terms of the optimisation criteria for different load cases.

Keywords: powertrain dynamics; automatic transmission; gear shift process; comfort; optimisation; pareto-optimal solution.

DOI: 10.1504/IJVD.2002.001985

International Journal of Vehicle Design, 2002 Vol.28 No.1/2/3, pp.171-188

Published online: 15 Aug 2003 *

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