Mean-Value Exergy Modeling of Internal Combustion Engines: Characterization of Feasible Operating Regions

In this paper, a novel mean-value exergy-based modeling framework for internal combustion engines is developed. The characterization of combustion irreversibilities, nonstoichiometric combustion, and thermal exchange between the in-cylinder mixture and the cylinder wall allows for a comprehensive description of the availability transfer and destruction phenomena in the engine. The model is applicable to internal combustion engines operating both at steady-state and over a sequence of operating points and is used to create maps describing the exergetic static behavior of the engine as a function of speed and load. The application of the proposed modeling strategy is shown for a turbocharged diesel engine. Ultimately, the static maps, while providing insightful information about inefficiencies over the operating range of the engine, are the enabling step for the development of exergy-based control strategies aiming at minimizing the overall operational losses of hybrid electric vehicles.