Isobutanol outperforms ethanol in small engine test

By Kris Bevill | November 03, 2011

Tests recently conducted by Briggs & Stratton Corp. to evaluate the effects of isobutanol on small engines suggest that it can be used in those engines without any of the problems associated with ethanol-blended fuel.  Tests were conducted on three small engines using gasoline containing 12.5 percent isobutanol provided by Gevo Inc. The results showed no engine or performance issues, maintained horsepower and torque levels and an equivalent or better performance than E10 at temperatures ranging from 40 degrees to 120 degrees Fahrenheit.  It was also noted that because isobutanol does not attract water like ethanol, it would have fewer issues as a result of long storage periods or seasonal use.

“These positive results show that isobutanol is an excellent gasoline additive,” Gevo CEO Pat Gruber said. “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.”

Briggs & Stratton President and CEO Todd Teske said his company is encouraged by the test results. “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,” he stated.

The Outdoor Power Equipment Institute, which represents more than 80 small engine and equipment manufacturers, including Briggs & Stratton, also spoke out in favor of isobutanol after reviewing the test results. “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,” OPEI President and CEO Kris Kiser said. “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.”

OPEI is a plaintiff in federal lawsuits against the U.S. EPA regarding its partial approval of E15 use and has stated many times its desire for alternative fuel blends to be approved with advance notice so that engineers can design equipment able to use the fuel blends. Despite its positive review of isobutanol, Kiser cautioned however, that neither OPEI nor Briggs & Stratton are ready to endorse isobutanol as a replacement for ethanol yet. “We’re not trying to make a policy statement,” he said. “We’re saying that if a dialogue is to be engaged on Capitol Hill, this should be included.”

The Briggs & Stratton test was initiated by Gevo. Jack Huttner, executive vice president of commercial and public affairs at Gevo, confirmed that the company is also currently supplying isobutanol for marine engine testing being conducted by marine group. Results of that test should become available by the end of November. Huttner said Gevo representatives have discussions with many companies that have an interest in alternative fuel performance, from pipeline companies to equipment manufacturers, and “whenever anyone has questions, we offer them to test it.”

One of isobutanol’s largest downfalls to this point has been its cost, but Huttner said Gevo expects to produce at a cost-competitive level as soon as its first commercial plant comes on-line in June.