Abstract :
This paper characterizes the exergy
(availability) analysis in bi-fuel (CNG and gasoline)
spark ignition engines. The engine is modeled based on a
thermodynamic quasi-dimensional (QD) two-zone model.
It solves the differential equations related to compression,
combustion and expansion. By an approximation method,
intake and exhaust processes are modeled. Using a
turbulent combustion model, the engine model has
capable to simulate burn rate, and compared to
computational fluid dynamic (CFD) models is faster. To
meet this objective, this model is developed based upon
the second law, and exergy analysis terms. These terms
are including thermo-mechanical availability, chemical
availability, heat transfer availability, work availability,
and the irreversible processes that are the source of
availability destroyed. Finally, in this paper the effect of
equivalence ratio, ignition time and engine of speed upon
the terms of availability, the first law of thermodynamics
(FLT) and the second law of thermodynamics (SLT)
efficiency are presented and are discussed.
