The Effects of Ethanol–gasoline Blend on Performance and Exhaust Emission Characteristics of Spark Ignition Engines

The effects of unleaded gasoline and unleaded gasoline–ethanol blends on engine performance and pollutant emissions were investigated experimentally in a single cylinder, four-stroke spark-ignition engine with variable engine speeds (2600–3500 rpm). Four different blends on a volume basis were applied. These are E0 (0% ethanol + 100% unleaded gasoline), E3 (3% ethanol + 97% unleaded gasoline), E7 (7% ethanol + 93% unleaded gasoline) and E10 (10% ethanol + 90% unleaded gasoline). Results of the engine test indicated that using ethanol–gasoline blended fuels improve output torque, power, volumetric efficiency and fuel consumption of the engine it was also noted that fuel consumption depends on the engine speed rather than the ethanol content for ethanol less than 10% blended ratio. CO and unburned hydrocarbons emissions decrease dramatically as a result of the leaning effect caused by the ethanol addition CO2 emission increases because of the improved combustion.