Performance and Emissions of Acetone-Butanol-Ethanol (ABE) and Gasoline Blends in a Port Fuel Injected Spark Ignition Engine

Acetone-Butanol-Ethanol (ABE), an intermediate product in the ABE fermentation process for producing bio-butanol, is considered a promising alternative fuel because it not only preserves the advantages of oxygenated fuels which typically emit fewer pollutants, but also lowers the cost of fuel recovery for each individual component during fermentation. An experiment was conducted using a Ford single-cylinder spark-ignition (SI) research engine to investigate the potential of ABE as an SI engine fuel. Blends of pure gasoline and ABE, ranging from 0% to 80% vol. ABE, were created and the performance and emission characteristics were compared with pure gasoline as the baseline. Measurements of brake torque and exhaust gas temperature along with in-cylinder pressure traces were used to study the performance of the engine and measurements of emissions of unburned hydrocarbons, carbon monoxide, and nitrogen oxides were used to compare the fuels in terms of combustion byproducts. Experiments were performed at a constant engine speed and a comparison was made on the basis of similar power output (Brake Mean Effective Pressure (BMEP)). In-cylinder pressure data showed that the peak pressure of all the blends was slightly lower than that of gasoline, except for ABE80 which showed a slightly higher and advanced peak relative to gasoline. ABE showed an increase in brake specific fuel consumption (BSFC); while exhaust gas temperature and nitrogen oxide measurements show that ABE combusts at a lower peak temperature. The emissions of unburned hydrocarbons were higher compared to those of gasoline but the CO emissions were lower. Of particular interest is the combined effect of the higher laminar flame speed (LFS) and higher latent heat of vaporization of ABE fuels on the combustion process.