A novel algorithm for computing the torque split for vehicles with multiple torque actuators will be presented. This technique is intended to be generic and easily extended to vehicles of different architectures. The usefulness of the approach taken will be shown for torque delivery under typical driving profiles (launch, acceleration, braking and cruising), as well as under racing conditions.
An open-loop torque model developed for a prototype supercar with a combustion engine and two electric motors will be outlined. This particular example describes the front- rear torque distribution, followed by the rear engine-motor torque split. In order to parameterize the formulation, the system constraints need to be addressed. Since there are three independent torque sources, at part-load conditions there are an infinite number of ways to distribute torque. A clear choice has to be made taking into account vehicle dynamics, energy management/fuel consumption, performance and thermal states.
Simulation results will demonstrate the benefits of this control model and the capability to define powertrain modes (electric only, minimize / maximize engine). Vehicle results will show how this approach can be used to adjust the torque split to maintain performance but distribute thermal loading between the front and rear motors. Finally, further applications of these algorithms will be summarized.