Combustion and Emission Characteristics of Ethanol-Methanol-Gasoline Blends in a Spark Ignition Engine

Depletion of fossil fuels and environmental pollution has led researchers to foreseethe need to develop bio-fuels. Alcohols are a major part of bio-fuels. This study debatescombustion performance and exhaust emissions from SI engine fueled with ethanol-methanolgasoline blends. The fuel blends contained %100 gasoline, %80 gasoline and %20 ethanol, %80gasoline and %20 methanol and %80 gasoline, %10 ethanol and %10 methanol by volume. Theexcess air coefficient were kept at the lean (0.9), stoichiometric(1.0) and rich (1.1) conditions.The effects of blended fuels on engine performance were investigated and results showed thatmethanol-gasoline blends presents the highest volumetric efficiency; on the other hand, neatgasoline showed the lowest volumetric efficiency, torque and brake power among all test fuels.Maksimum in-cylinder pressure was occured ethanol-methanol-gasoline blend at richcondition. Results indicated that when the engine was fueled with ethanol-methanol-gasolineblends, the concentrations of CO and HC (unburnt hydrocarbons) emissions were significantlydecreased, compared to the neat gasoline. Ethanol-methanol-gasoline blends presented thelowest emissions of CO and HC at stoichiometric and poor conditions but ethanol-methanolgasoline blend was the lowest at rich conditions among all test fuels. In addition to this NOxemission increased when ethanol and/or methanol contents increased except stoichiometriccondition in the fuel blends.