Comparative Exergy Analysis of Fuel Additives Containing Oxygen and HC Based in a Spark-Ignition (SI) Engine

Abstract

The effects of fuel additives have been investigated based on the second law (exergy analysis) of thermodynamic in an SI engine. Exergy terms such as the total cylinder exergy, exergy transfers via heat transfer and work, fuel chemical exergy and irreversibility were computed for closed part of the engine cycle. Additionally, the exergy distributions, the brake power, brake specific fuel consumption (BSFC), first (energy) and second law (exergy) efficiencies were determined. The experimental data, especially the measured cylinder pressure data, were used to calculate the exergy terms with a home-made code. Test results showed that when compared with gasoline operation, the peak cylinder pressure for M10, E10, and S10 was increased by 18.65%, 12.75% and 15.52%, respectively, and also shifted towards to TDC. In addition, the energy and exergy efficiency decreased with the addition of methanol, ethanol, and solketal. The maximum reduction in the exergy efficiency occurred for the S10, and this reduction was determined as about an 8.42%. The results also revealed that the gasoline blends containing a 10% methanol, ethanol, and solketal were an unfavorable choice from the second-law perspective, due to the reduction in the exergy.