This study discusses performance and exhaust emissions from spark-ignition engine fueled with ethanol emethanolegasoline blends. The test results obtained with the use of low content rates of ethanol emethanol blends (3e10 vol.%) in gasoline were compared to ethanolegasoline blends, methanol egasoline blends and pure gasoline test results. Combustion and emission characteristics of ethanol, methanol and gasoline and their blends were evaluated. Results showed that when the vehicle was
fueled with ethanolemethanolegasoline blends, the concentrations of CO and UHC (unburnt hydrocarbons) emissions were significantly decreased, compared to the neat gasoline. Methanolegasoline blends presented the lowest emissions of CO and UHC among all test fuels. Ethanolegasoline blends showed a moderate emission level between the neat gasoline and ethanolemethanolegasoline blends, e.g., ethanolegasoline blends presented lower CO and UHC emissions than those of the neat gasoline but higher emissions than those of the ethanolemethanolegasoline blends. In addition, the CO and UHC decreased and CO2 increased when ethanol and/or methanol contents increased in the fuel blends. Furthermore, the effects of blended fuels on engine performance were investigated and results showed that methanolegasoline blends presents the highest volumetric efficiency and torque; ethanolegasoline blends provides the highest brake power, while ethanolemethanolegasoline blends showed a moderate level of volumetric efficiency, torque and brake power between both methanolegasoline and ethanol egasoline blends; gasoline, on the other hand, showed the lowest volumetric efficiency, torque and brake power among all test fuels