The Effect of Ethanol Fuels on the Power and Emissions of a Small Mass-Produced Utility Engine 2018-32-0056
The effect of low level ethanol fuel on the power and emissions characteristics was studied in a small, mass produced, carbureted, spark-ignited engine. Ethanol has been shown to be attractive fuel due to it being renewable, having anti-knock properties, and its potential power and emissions benefits with extensive studies for use in the automotive industry. With increasing availability and the possible mandates of higher ethanol content in pump gasoline, there is interest in exploring the effect of using higher content ethanol fuels in the small utility engine market. In this study, ethanol content was varied from 0% to 25% by mass in 5% increments with a 91 octane gasoline balance. Using a hydraulic dynamometer setup, the engine throttle was set wide open and speed was swept observing engine torque and engine emissions output. Overall, the experimental results showed increasing ethanol content resulting in the engine operating closer to stoichiometric fueling and having a small gain in power output. Additionally, it was found that carbon monoxide and carbon dioxide emissions were reduced with the trade-off of increased oxides of nitrogen emissions.