Solution of a hybrid optimal control problem for parallel hybrid vehicles subject to thermal constraints

The class of dynamical systems that exhibit both continuous and discrete dynamics can be referred to as hybrid systems. One example of hybrid systems constitute nowadays parallel hybrid electric vehicle (HEV) configuration, that provide continuous dynamics, such as the torque-split between motor/generator and the internal combustion engine, as well as discrete decisions, such as choice of driving mode and catalytic converter heat-up. In this paper, an algorithm that combines the advantages of direct and indirect methods for solving optimal control problems is proposed. The applicability of the proposed algorithm is demonstrated on a simulated parallel HEV.