  The exergy, or availability, is a thermodynamic concept representing the
useful work that can be extracted from a system which moves from a given state
to an equilibrium point with the environment. It is also a system metric,
formulated from the first and the second law of thermodynamics, encompassing
the interactions between subsystems and their irreversibilities. Thus, an
exergy-based analysis allows to identify the valuable portion of a system's
energy, which can be converted into useful work. Within this framework, an
exergy-based analysis for ground vehicles, namely, Electric Vehicles (EVs) and
Hybrid Electric Vehicles (HEVs), is proposed. This study, a first to the
authors' knowledge, builds a comprehensive modeling framework, accounting for
the different energy storage/conversion devices of the powertrain, which can be
employed to quantify how efficiencies and inefficiencies are distributed among
the components of the propulsion system and drivetrain. This information is of
paramount importance and can be employed for further optimization of the
vehicle design or for the development of exergy management strategies aiming at
minimizing inefficiencies, rather than fuel consumption. Eventually, the
effectiveness and potentialities of the proposed approach are shown considering
two case studies based on an EV and a parallel HEV, respectively.
