Development and Implementation of an Optimal Torque Split Strategy on a Parallel Hybrid Vehicle

In this study, an alternate way of development and implementation of control strategy for torque split of a Hybrid Electric Vehicle (HEV) is proposed. The control strategy evaluates each and every operating point for Internal Combustion Engine (ICE) and electric motor-generator (E-machine) corresponding to all possible torque split combinations at present time instant and finally chooses one combination with the least cost function, which is estimated by converting electrical energy into equivalent fuel consumption[2]. Henceforth, the control strategy is able to perform real time iterations to choose the E-machine and ICE torque combinations with least effective fuel consumption also referred herein to as the optimal operating points. As a result, by running the vehicle at optimal operating points, overall fuel consumption over the complete drive cycle is reduced. Once such a strategy is formulated and verified, the same is implemented in a hybrid vehicle using dSPACE Microautobox, a rapid control prototyping toolbox. To incorporate the same, changes in vehicle CAN architecture along with the base strategy in the Hybrid Control Unit (HCU) are made. Once the set-up is complete, the vehicle with the new control strategy is tested over Modified Indian Drive Cycle (MIDC) and on-road and the results of the same are presented in this paper.