Effect of Ethanol-Gasoline Blends on Adsorption/Desorption Process in SI Engine

Ethanol is regarded as a potential alternative fuel for combustion engine as it provides lower exhaust emissions, higher efficiency and higher octane rating. However, the solubility of ethanol in oil can effect lubricant quality. The impact of ethanol-blend gasoline on lubricants is a matter of concern that must be addressed. With this in mind, the current study investigates the effect of blending ethanol with gasoline on the oil layer adsorption/desorption mechanism. The blends used for the study are E0, E5, E10, and E15. The study is carried out with the help of a mathematical model that predicts the fuel adsorbed/desorbed in the oil layer of an engine. The mathematical model predictions are compared to experimental results obtained on a single-cylinder gasoline engine. Fuel adsorbed in the oil layer ranges from 0.46% for E0 fuel to 0.35% for E15 fuel. Similarly, the desorbed fuel ranges from 0.45% to 0.29% as the ethanol fraction increases from 0% to 15%. Despite the fact that the amount of fuel adsorbed/desorbed in the oil layer decreases as the ethanol fraction increases, the amount of fuel stored in the oil layer (i.e., the difference between adsorbed and desorbed fuel) increases from 0.01 percent to 0.06 percent which can significantly degrade the lubricant quality.