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The Influence of Fuel Composition and Renewable Fuel Components on the Emissions of a GDI Engine
ISSN: 0148-7191, e-ISSN: 2688-3627
To be published on June 23, 2020 by SAE International in United States
Investigations were performed, in which the emission behavior of renewable and conventional fuels of different composition and renewable fuel components was observed. The influence on the emissions of the start of injection at different load points was investigated. This shows how much wall and valve wetting affects the mixture formation of the different fuels. Further, the air fuel ratio in an operating point for catalyst heating, with medium engine temperatures, was varied. The latter shows the ability of evaporation of the fuels at engine warm-up conditions and sub-stochiometric λ-Values. The studied fuels were four fuel mixtures of significantly different composition of which three were compliant with the European fuel standard EN 228. A RON 98 in-field fuel, a Euro 6 reference fuel, an Anti-Spark-Fouling (ASF) fuel (designed for minimum soot production) and a potentially completely renewable and CO2-neural fuel, which is designed by Dr. Ing. h.c. F. Porsche AG, named POSYN (POrsche SYNthetic fuel) were chosen. Additionally, the fuel components Ethanol as classic biofuel, Isopropanol, Isobutanol and methyl tert-butyl ether (MTBE), which were chosen by the possibility of renewable production, were investigated. The properties of MTBE as an ether differ from those of the alcohols, which can be observed in the emissions. Due to the huge difference in the composition of the fuels (oxygen or aromatic content) significant differences could be observed in the particulate matter and hydro carbon emissions, especially when fuel hits the wall of the combustion chamber or the piston during the injection. Nitrogen oxides can also be influenced positively by the fuel composition.