NMMA summarizes boat testing for isobutanol-gasoline blends
21 November 2011
The National Marine Manufacturers Association (NMMA) released a report evaluating isobutanol, provided by Gevo, Inc., as a fuel blendstock for the boating industry. Over the summer, NMMA conducted two tests, an emissions test and a product test, to evaluate the effects of butanol-blended fuels in a marine environment. The project aimed to determine if isobutanol could be a better alternative to ethanol blends for the boating industry.
The emissions tests compared a 16.1% isobutanol blend to indolene, the standard gasoline used for engine testing. Among the findings were:
Using an Evinrude E-TEC 175 Stratified Charged Direct Fuel Injection Two-Stroke engine on an 18' Mako Boat, the team found that HC + NOx emissions are virtually the same between the two fuels and CO is reduced using isobutanol.
Using a Rotax 1503 Supercharged Four-stroke engine on a jet-boat, the team found that HC decreased slightly and NOx increased slightly using isobutanol but the total HC+NOx was virtually the same between the two fuels. CO is reduced using isobutanol.
The 16.1% isobutanol blend produced similar engine enleanment as a 10% ethanol-indolene blend.
Isobutanol can be blended into gasoline at higher percentages than ethanol, and unlike ethanol-blended gasoline, isobutanol blends do not cause phase separation when water enters a boat’s fuel system—an important distinction between ethanol and isobutanol blends.
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