Title: Further study of the optimisation of the tractive efficiency of all-wheel-drive vehicles
Authors: Wei Huang; J.Y. Wong; Zeljko Knezevic
Automotive and Surface Transportation, National Research Council of Canada, 2320 Lester Road, Ottawa, ON K1V 1S2, Canada
Vehicle Systems Development Corporation, 49 Fifeshire Crescent, Ottawa, ON K2E 7J7, Canada
General Dynamics Land Systems - Canada, 1991 Oxford Street, London, ON N5V 2Z7, Canada
Abstract: This paper examines the tractive efficiency of all-wheel-drive vehicles in general and the slip efficiency in particular. It focuses on the analysis of the conditions for achieving the optimal slip efficiency. Results of detailed theoretical analyses indicate that all drive wheels operating at the same slip will be the necessary and sufficient conditions for achieving the optimal slip efficiency, if their thrust-slip relationships are either linear or nonlinear with similar characteristics. If the thrust-slip relationships of the drive wheels are nonlinear with different characteristics, the optimal slip efficiency will be reached with the slips of the drive wheels not being equal. The basic findings of this investigation are substantiated with experimental data. The results of this study suggest that the requirement for all drive wheels operating at the same slip provides a reasonable basis for a practical control strategy of an active system to distribute torque (thrust) among the drive wheels to achieve the optimal (or close to the optimal) slip efficiency of all-wheel-drive vehicles under most operating conditions.
Keywords: all-wheel-drive vehicles; torque distribution; thrust distribution; linear thrust-slip relationship; nonlinear thrust-slip relationship; off-road wheeled vehicles; optimisation; slip efficiency; tractive efficiency; tractive performance; off-road vehicles; traction.
Int. J. of Heavy Vehicle Systems, 2014 Vol.21, No.2, pp.123 - 151
Available online: 27 May 2014