Keywords: spark ignition engines, modelling, second law of thermodynamics, exergy analysis, availability, irreversibilities, exergy destruction, compression ratio, fuel-air equivalence ratio, spark timing
Exergy analysis of SI engines
In this study, exergy (availability) analysis of a Spark Ignition (SI) engine has been performed theoretically during compression, combustion and expansion processes of the engine cycle. For this purpose, a thermodynamic-based engine cycle model is developed without considering the geometric features of fluid motion. Through the analysis, the effects of changing some design and operating parameters, such as compression ratio, fuel-air equivalence ratio and spark timing on the variation and destruction of exergy have been investigated. It was obtained that design and operation conditions have considerable effects on the variation of exergy and irreversibilities during investigated parts of the cycle.