Energy management of HEV to optimize fuel consumption and pollutant emissions

Electric hybridization of vehicles propelled by gasoline engine proved to be a solution to reduce fuel consumption. Indeed, in Hybrid Electric Vehicle (HEV), the electrical machine and battery offer an additional freedom degree to ensure vehicle displacements, through the control structure, more particularly the energy management system (EMS). Another constraint is to respect more and more stringent standards of pollutant emissions. In this paper, several energy management strategies are proposed to optimize jointly the fuel consumption and pollutant emissions. An accurate simulation HEV model, with parallel architecture and spark-ignition engine, is built with its corresponding control structure and EMS in order to test the different strategies. Some heuristic strategies are proposed, then a mixed criterion is formulated, and Dynamic Programming, for on-line minimization, and on-line strategies, borrowed from optimal control, are described. The dfferent strategies are compared from simulation results on the HEV model. Conclusions for setting the criterion and tuning the on-line strategy are given.