10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Gasoline Aromatic and Oxygen Content Impact on Formation of Secondary Aerosols from a GDI Vehicle
PATRICK ROTH, Jiacheng Yang, Ayla Moretti, Thomas D. Durbin, David R. Cocker III, Akua Asa-Awuku, Georgios Karavalakis, University of California, Riverside
Abstract Number: 1584 Working Group: Combustion
Abstract Gasoline powered motor vehicles have been identified as the dominant PM contributor (primarily in the form of SOA) surrounding heavily urbanized areas. Future scenarios indicate that the largest impact on premature mortality in California will be attributable to transportation emissions, particularly vehicular exhaust. Gasoline vehicles emit a variety of volatile organic compounds (VOCs), and deviating concentrations of NOx, CO, CO2, and PM. The PM that is emitted from gasoline vehicles is a complex mixture of black carbon (BC), organic aerosols (POA), and inorganic salts which varies with engine technology, age, and fuel used.
As of 2015, GDI engines accounted for approximately 45%, and 60% of the North American and European market respectively. PFI vehicles have significant advantages (low PM), but are expected to struggle meeting future legislation and fuel economy regulations. GDI engines, on the other hand, have improved fuel economy through an increased compression ratio and better air/fuel ratio accuracy. Another major driving force to differing emissions is variations in fuel content. Studies have shown that by varying ethanol and aromatic content, several regulated emissions also change. These differences can greatly affect both the tailpipe pollutant measurements and also the potential secondary aerosol formation from the exhaust.
For this study, eight gasoline fuels were blended to simulate high and low aromatic fuels (20% and 30% by volume) along with varying ethanol content (0 to 20% by volume). These fuels were tested with one MY-2017 GDI vehicle over a cold start LA92 driving cycle, in duplicate. The tailpipe emissions were measured to certification standards, while simultaneously injecting the tailpipe emissions into UCR’s 30m3 Mobile Atmospheric Chamber (MACh). The emissions were injected through the full driving cycle, and then subsequently aged for approximately eight hours. While the emissions were aging, the aerosol and gasses were monitored in real time with a host of gas phase and particle instruments. The presented work will explore the effects of low vs high aromatic fuel blends for E0, E10, E15, and E20 fuels, while also examining the differences in fuel blending techniques (match vs splash).