Black Carbon Emissions from Light-duty Passenger Vehicles Using Ethanol Blended Gasoline Fuels

Abstract

Vehicular emissions of soot vary with the driving conditions and fuel properties. In 2017, China's central government released a policy to promote ethanol blended gasoline fuels, and this policy will be rolled out nationwide in 2020. It is necessary to characterize the emission differences between traditional vehicular fuels used in China and ethanol blended fuels. In this study, black carbon (BC) emissions from three gasoline light-duty passenger vehicles (LDPVs) were measured using the New European Driving Cycle (NEDC) and the Worldwide harmonized Light vehicles Test Cycle (WLTC). This study utilized three fuels, namely, two E10 fuels and a traditional gasoline (E0). The experimental results showed that the use of E10 blends (gasoline containing 10% ethanol) reduced BC emissions by 7-38%. Based on phaseseparated analysis, BC emissions in the initial driving phase and the high-speed phase (e.g., the 1 st ECE-15 phase in the NEDC and the extra-high speed phase in the WLTC) represented the majority (86-96%) of the total BC emissions, and the emission factors during the 1 st ECE-15 phase (NEDC) and the low-speed phase (WLTC) were 0.36 mg km -1 and 0.37 mg km -1 lower, respectively, for the ethanol-blended fuels than the ethanol-free fuel. Furthermore, we found that using ethanol-blended fuels could reduce the mass concentration of the BC emitted during cold starts, which lasted 53-95 s for the tested vehicles, by 4.28 ± 4.19 mg km -1 and 2.06 ± 0.17 mg km -1 in the NEDC and the WLTC, respectively.