Influence of Ethanol and MTBE Proportion in China VIB Gasoline on Vehicle Particulate Emissions 2021-01-0540
With the implementation of the China VI gasoline standards, the use of ethanol is expanding and is intended to further reduce vehicle criteria gaseous and particulate emissions. However, due to the constraints of biomass ethanol production, petroleum derived Methyl tert-Butyl Ether (MTBE) is being used in addition to ethanol to improve fuel octane and maintain oxygen content. The impact of these mixed oxygenates on vehicle emissions are studied in this paper. The correlation of fuel characteristics to vehicle particulate emissions and their predictive indices has been investigated. The results from this study suggest some alternatives to existing fuel indices due to oxygenate contribution. Additionally, this paper studies, the emissions of three direct-injection turbocharged vehicle models focusing on particulate emissions from the Worldwide Harmonized Light Vehicles Test Cycle (WLTC). The test fuels were China VIb gasoline, blended with different ratios of ethanol and MTBE. The results show the current PMI equation does not correlate well to vehicle PM emission due to oxygenates impact, while showing good correlation when the fuel contains oxygenates. Two out of three vehicles show positive particulate emissions correlation to ethanol and negative correlation to MTBE.