Energy management of plug-in hybrid electric vehicles (HEVs) has different challenges from non-plug-in
HEVs, due to bigger batteries and grid recharging. Instead of tackling it to pursue energetic efficiency, an
approach minimizing the driving cost incurred by the user – the combined costs of fuel, grid energy and
battery degradation – is here proposed. A real-time approximation of the resulting optimal policy is then
provided, as well as some analytic insight into its dependence on the system parameters. The advantages
of the proposed formulation and the effectiveness of the real-time strategy are shown by means of a
thorough simulation campaign.