E20 fuel, which blends 20 percent ethanol with gasoline, reduces the tail pipe emissions of hydrocarbons and carbon monoxide, compared with traditional gasoline or E10 blends, according to a new study in the Journal of Automobile Engineering. In addition, the research found no measurable impact to vehicle drivability or maintenance in conventional internal combustion engines.

E20, the study's authors say, could be used to reduce overall vehicle emissions at a time when many states and the U.S. Department of Transportation are considering policies that would increase the ethanol percentage in standard gasoline. The results are also being used by the Environmental Protection Agency to promote the federal Renewable Fuel Standard program.

The study tested the use of E20 in 10 older gasoline vehicles that had logged over 100,000 miles and were not designed for ethanol fuel mixtures. Researchers analyzed the vehicles running on E20 fuel periodically both for emissions and overall wear and tear.

Results revealed an average emissions reduction for carbon monoxide of 23 percent as well as a 13 percent reduction for hydrocarbon emissions, compared to conventional gasoline, with no measurable stress on vehicle operation or mechanics.

"Currently, numerous commercially available gasoline brands contain 10 percent ethanol," notes Brian Hilton, senior staff engineer at the center, a component of the RIT's Golisano Institute for Sustainability. "There have been concerns raised that any increase in blend would negatively impact standard internal combustion engines, however our data shows that vehicle performance remained constant, while carbon monoxide and hydrocarbon emissions were decreased even over E10 blends."

Citation: B Hilton, B Duddy, 'The effect of E20 ethanol fuel on vehicle emissions. Proceedings of the Institution of Mechanical Engineers, Part D: Journal of Automobile Engineering, 2009; 223(12), 1577; doi: 10.1243/09544070JAUTO1188