Assessing the effects of ethanol additive and driving behaviors on fuel economy, particle number, and gaseous emissions of a GDI vehicle under real driving conditions

Abstract Gasoline direct injection (GDI) vehicles operating on real roads produce particle number (PN) emissions. Ethanol, which is a vehicle oxygenated fuel, can meet stringent PN and gaseous emission regulations owing to its low carbon content, green sustainability, and clean combustion benefits. In this study, the fuel consumption (FC), PN, and gaseous emissions of a GDI vehicle were experimentally investigated using a chassis dynamometer following real driving emission (RDE). Two driving behaviors, the normal and aggressive driving modes, were tested with different ethanol fractions of gasoline (G100), 5% volume content in the blended fuel (G95E5), and 10% volume content in the blended fuel (G90E10). The results indicated that under the RDE test procedure, the FC, exhaust gas temperature (EGT), PN, carbon monoxide (CO), carbon dioxide (CO2), and nitrogen oxide (NOX) emissions in the aggressive driving mode were higher than those in the normal driving mode. When ethanol was added to gasoline, the FC and CO2 emissions of the blended fuels were higher than those of G100, whereas the CO and EGT of the blends decreased. The addition of small amounts of ethanol had little effect on the NOX emissions. As for PN, the PN emission of G95E5 was higher than that of G100. As the ethanol fraction further increased, the PN emission of G90E10 was the smallest among the three fuels. The GDI vehicles fueled with 10% ethanol achieved lower PN and CO emissions at a slight sacrifice in FC under real driving conditions.