Washington, D.C. – The U.S. Department of Energy (DOE) has released preliminary results from a test program initiated in August 2007 to assess the potential effects of higher intermediate ethanol blends on conventional vehicles and other engines that rely on gasoline. The program focuses specifically on E15 and E20 (gasoline blended with 15 and 20 per cent ethanol, respectively) on emissions, catalyst and engine durability, driveability and operability.
The tests were performed on 13 popular late-model vehicles and 28 small non-road engines, including lawn equipment and generators.
On vehicles tested with E15 and E20 against regular gasoline, the researchers found that tailpipe emissions were similar, and under normal operations, catalyst temperatures in the cars were largely unchanged. When tested under full-throttle conditions, about half the cars exhibited slightly increased catalyst temperatures with the enthanol blends. Overall, based on informal observations during testing, driveability was unchanged.
When the small non-road engines were tested with E15 and E20 compared with traditional gasoline, the researchers found that the regulated emissions remained largely unchanged, but engine and exhaust temperatures increased as ethanol content increased. Engine performance was inconsistent, even with traditional gasoline, and commercial engines exhibited no particular sensitivity to ethanol from a durability perspective. The effect of E15 and E20 on the durability of smaller, less expensive residential engines such as weed trimmers was not clear, given that a number of these engines failed regardless of fuel type.