The Case of Flex-Fuel Vehicles

While most automotive fuel sold in the United States contains 10% ethanol, it is also possible to power the vehicle on a blend that is primarily ethanol. The optimum blend sold in both the U.S. and European markets for flexible-fuel vehicles is E85 (mixture of gasoline containing 85% of ethanol). In Brazil, flex-fuel vehicles can operate with ethanol mixtures up to ElOO. The Brazihan 2008 Honda Civic flex-fuel car is built with a secondary reservoir gasoline tank. In March 2009 the first Polo E-Hex was launched in Brazil without the auxiliary gasoline tank. Ethanol-based engines can be used to power automobiles, tractors, city buses, distribution trucks, and waste collectors. 

As with any other combustion reaction, ethanol reacts with oxygen to form carbon dioxide and water, releasing significant amounts of heat  

The high temperature that is generated from combustion and the large volume of combustion gases cause substantial pressure accumulation in the engine cylinder chamber, which pushes back on the piston through the transfer of work. 

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