Use of Detailed Hydrocarbon Emission Analysis to Identify Synergistic Effects in Renewable Gasoline Fuel Blends for Significant Reduction of Aromatic Hydrocarbon As Well As Total Hydrocarbon Emissions of a Small Gasoline-Powered ICE

With rising awareness of man-made climate change the interest in measures to reduce CO₂ and other greenhouse gas (GHG) emissions increases. The use of renewable liquid fuels is one way to achieve reduction of GHG emissions. Due to their different chemical composition, gasoline fuels containing significant shares of renewable components also produce different pollutant emissions including hydrocarbon (HC) emissions amongst others such as particular matter, carbon monoxide, and nitrogen oxides. In this study the effects of renewable fuel components on amount and type of individual hydrocarbon components in exhaust emissions of a small gasoline-powered internal combustion engine were investigated via gas chromatographic analyses. Therefore, three different gasoline fuels with varying degrees of sustainable components and their respective HC exhaust emissions were investigated in single compound resolution. HC emissions could be categorized into combustion side products and unburned fuel fractions according to their origin. Both fractions showed significantly different sensitivity on change of engine operation. Whilst combustion side product emissions showed little sensitivity, unburned fuel emissions proved to be highly sensitive on engine operation. The combustion rates of the unburned fuel fraction of HC exhaust emissions were investigated via comparison to the composition of the fuels used. Thereby, large differences in combustion rates of different fuel components could be identified with aromatics generally showing poorest conversion. Promising synergies between renewable gasoline compounds such as EtOH or EtBE and the hydrocarbon part of fuels (be it synthetic or conventional gasoline) could be identified which showed significant reduction of both total hydrocarbon emissions as well as especially dangerous aromatic hydrocarbon emissions.