As I mentioned before, the researchers would be the first ones to point out that the results are preliminary, but they are interesting. The above bar graph reveals the results of their tests showing that two models showed an increase of 1% in fuel economy for the E30 blend over conventional gasoline (the Camry and the Fusion), and the flex-fuel vehicle saw an amazing 15% increase in its E20 blend over conventional gasoline. Although unexpected, the researchers believe that some engines might have 'sweet spots' at which a certain blend might have the optimum combination of ethanol and gasoline to allow for a high mileage.
But what might be even more interesting is that all of the models of cars in all of the blends outperformed their calculated MPG based on their penalties for decreased energy densities. In other words, ethanol's energy density should result in a decrease in mileage by 2.7% for every 10 percent of ethanol blended into the gasoline. Below is an example from the sited study to reveal how the data bumped above the calculated energy density for the Toyota Camry.
As you can see above, the apparent 'sweet spot' in the Camry is around E30. Even though these tests need to be corroborated, they agree with similar results seen in 2005 in the study found at http://www.ethanol.org/pdf/contentmgmt/ACEFuelEconomyStudy_001.pdf.
While these studies show that E20 and E30 could be incorporated into non-flex fuel vehicles, a better potential benefit of this study is the realization that it may be possible to engineer a car engine to favor ethanol over gasoline, thereby relieving any potential MPG dip due to lower energy density. This would seem to parallel the finding in the previous post that a turbocharged engine built with ethanol in mind might be able to alleviate several of the potential negative aspects of ethanol.