A University of Nebraska¹ study published in September 2009 finds that higher ethanol blends increase engine efficiency.

The study, which was funded by the Nebraska Corn Board, found that high ethanol blends provide better energy conversion within an engine than other fuels, meaning they used less energy to travel further. The report says that E85 improved energy conversion by 13, 9 and 14 percent respectively when compared to E10, for the light, medium and heavy loaded vehicles tested.

Vehicles went through chassis dynamometer? testing as part of the study. The dynamometer simulated different road and vehicle operating conditions, allowing researchers to fully measure a number of important data points to measure the performance of different ethanol blends.

The researchers acknowledged that higher ethanol blends like E85 have a lower energy density, or fewer BTUs per gallon, than E10. That often leads to fewer miles per gallon or MPG? for higher ethanol blends, but that gets partly offset by ethanol’s improved efficiency.

“While fewer BTUs typically means fewer miles per gallon, energy density is only part of the equation when considering fuel economy,” said Loren Isom, one of the researchers in the study.

Isom said that fuel economy is a combination of fuel efficiency and fuel price. On this point, higher ethanol blends may be the better choice. It depends on fuel prices at the time and also specific vehicles may test out differently based on engine design and settings. Because of increased efficiency from ethanol, for the fuel prices looked at in the study, e85 was the best choice every time.

References:

¹Mid-level Ethanol Blend Study: Chassis Dynamometer Study of Flex Fuel Vehicles

External links:

University of Nebraska-Lincoln Industrial Products Center