Isobutanol Fuel Blends Show Promise in Outdoor Power Equipment Engines
Dec 15, 2011
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New testing results show that isobutanol fuel blends do not cause irregular or unstable engine or performance issues in small engines such as those used in outdoor power equipment, according to the Outdoor Power Equipment Institute (OPEI). OPEI recently commissioned testing of on Briggs & Stratton small engines for a side-by-side evaluation of the performance, durability, and emissions of ethanol and isobutanol fuel blends. The results suggest isobutanol could help meet the renewable fuel mandate with minimal to no impact on existing equipment and off-road vehicles.

"It shows us that isobutanol could be a biofuel alternative that can be introduced into the existing supply chain without the potential disruption and harm to our outdoor power equipment engines,” said Kris Kiser, OPEI president and CEO. “In the economic interest of our members and the safety interest of consumers, we need to be open to a biofuel that can perform reliably in the millions of products on the market - lawnmowers, chainsaws, motorcycles, snowmobiles, ATVs and UTVs, boats, and older cars.”

After testing three different Briggs & Stratton engine models on gasoline containing 12.5% isobutanol, the following results were recorded:
• No engine or performance issues were found while running on isobutanol.
• Horsepower and torque levels remained the same while running on isobutanol.
• Equivalent or better performance than E10 at temperatures ranging from 40°F to 120°F.
• No significant change in emissions (HC+NOx) levels.

On advantage is that isobutanol does not absorb water like ethanol. This will lead to fewer problems in the seasonal use conditions and long storage periods that are common with small engine applications.

OPEI has been engaged in an ongoing battle to keep ethanol blends of gasoline fuels from being sold as auto fuels. A consortium of companies and organizations, including OPEI, fear that consumers may suffer equipment damage when E15 fuels are used in outdoor power equipment and other equipment that has not been designed for its use. Despite their efforts E15 fuels – containing 15% ethanol – were allowed to go on-sale in the United States.

Briggs & Stratton ran a test program with isobutanol provided by Gevo, a leading renewable chemicals and advanced biofuels company. Isobutanol, which can be produced out of corn starch, cellulosic materials, agricultural residues, and other ethanol feedstocks is an alcohol that acts like a hydrocarbon. It is a four-carbon molecule that could function as a “drop-in” product to allow customers to replace petroleum-derived raw materials with isobutanol-derived raw materials without modification to their equipment or production processes.

"We are very interested in alternative fuels that do not cause damage to the substantial number of engines in use today while lessening the country's dependency on foreign oil,” said Todd Teske, Chairman, President & CEO of Briggs & Stratton Corp.

“These positive results show that isobutanol is an excellent gasoline additive,” said Pat Gruber, CEO of Gevo. “If isobutanol blends run well in small engines, they should run well in all engines without the need for flex fuel retrofits, blender pumps or new infrastructure as our own, previous testing, has shown. Renewable isobutanol should therefore make it easier for the nation to gain energy independence and meet mandated biofuel targets.”

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