Because the molecules of ethanol contains oxygen. Making fuel ethanol mixed in a ratio much. Tends to cause complete combustion of fuel other than with the ethanol mix is less. The exhaust emissions from engines using fuel gas gasoline blended with ethanol. The exhaust should not exceed the standard of motorcycle identified in 2552, the year of the experiment, this time the exhaust emissions are not to exceed the standards set. So it shows that the United States can be fueled with. Ethanol is an alternative fuel mixture in the engine, with a little fine tuning.