The aim of this experimental study was to investigate the effect of addition of methanol and ethanol (5% - 10% and 15%) as a fuel at low rates to gasoline fuel against performance, and emissions characteristics. The experiments were car-ried out in a single cylinder, four-stroke, air-cooled spark plug ignition engine at various engine loads (2 - 2.5 - 3 - 3.5 and 4 Nm) and constant engine speed (2500 rpm). Performance, and emission characteristics of gasoline, methanol-gasoline and ethanol-gasoline blends were evaluated. When the results are examined, with the addition of ethanol and methanol, the specific fuel consumption and specific energy consumption increased, while the brake thermal efficiency decreased. Apart from that, CO and HC emissions have improved. The lowest CO and HC emissions were obtained in G85M15 and G85E15 fuels, respectively. Compared to gasoline, a reduction in CO and HC emissions of over 50% was observed.

In this study; 95 octane unleaded gasoline and bioethanol were tested as fuel in a spark-ignition engine by blending bioethanol with gasoline in certain proportions (2%, 4%, 6%, 8%, 10%). Tests were carried out at five different engine loads for a constant engine speed of 2500 rpm. The variations in engine performance parameters (engine torque, engine power, brake thermal efficiency, brake specific fuel consumption, brake specific energy consumption) and exhaust emissions (exhaust gas temperature, HC, CO, CO 2 and O 2) were investigated on the basis of test fuel and engine load. According to the test results, with the increase of bioethanol ratio in the blend, brake specific fuel consumption values increased by 9.71% and brake thermal efficiency values decreased by approximately 4.97% compared to gasoline. There was decrease up to 35.56% and up to 23.77% in HC and CO emissions respectively, and an increase by 6.01% in CO 2 emissions with bioethanol addition.