Novel Exergy-wise predictive control of Internal Combustion Engines

Abstract

Exergy is an effective metric to evaluate the performance of energy systems. Exergy analysis has been extensively used to study and understand loss mechanisms of Internal Combustion Engines (ICEs). However knowledge from exergy analysis has not been used for control of ICEs. This paper presents the first application of exergy-based control to ICEs. In this paper, an exergy model is developed for an advanced ICE with low temperature combustion mode that has higher efficiency compared to conventional diesel and spark ignition engines. The exergy model is based on quantification of the Second Law of Thermodynamic (SLT) and irreversibilities which are not identified in commonly used First Law of Thermodynamics (FLT) analysis. An optimal control method is developed based on minimizing irreversibilities and exergy losses. The new controller finds the optimum combustion phasing at every given engine load to minimize exergy destruction/loss. Application of the new developed control algorithm is demonstrated for a Combined Heat and Power (CHP) case study. The results show that by using the exergy-based optimal control strategy, the engine output power and exhaust exergies are maximized.