Availability analysis of n-heptane/iso-octane blends during low-temperature engine combustion using a single-zone combustion model

• A zero-dimensional single-zone combustion model is developed for LTC engines.
• The effects of intermediates and fuel compositions are examined.
• Chemical availability of reactants, intermediates and products differ greatly.
• Octane content shows profound effects on availability variation.

A zero-dimensional single-zone combustion and an availability balance model for low temperature combustion (LTC) engines have been developed combined with skeleton mechanism of primary reference fuel and the first and second law of thermodynamics. The variation of system availability is analyzed, and the effects of nine major species (OH, CH2O, H2O2, C3H6, C8H18, C7H16, CO, CO2, H2O) on availability conversion are studied. The influences of fuel octane number on the availability of LTC process are studied to investigate the effects of fuel characteristics on availability destruction of HCCI combustion process. The irreversibility increases and heat transfer availability decreases with the rise of iso-octane volume fraction in primary reference fuels (PRFs).