A new University of Nebraska study 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 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 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.
“Fuel economy is actually a combination of fuel efficiency and fuel price, and on that point, higher ethanol blends may be the better choice,” said Isom, who is with the University of Nebraska’s Industrial Agricultural Products Center. “It just depends on fuel prices at the time. Specific vehicles may test out differently based on engine design and settings, but increased efficiency from ethanol blends make sense, and for the fuel prices we looked at in the study, e85 was the best choice every time.”