10th International Aerosol Conference September 2 - September 7, 2018 America's Center Convention Complex St. Louis, Missouri, USA
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Investigating the Effect of Varying Ethanol Content and Driving Conditions on FFV-GDI Vehicle Emissions with the Addition of an Anthropogenic Surrogate
PATRICK ROTH, Jiacheng Yang, Ayla Moretti, Thomas D. Durbin, David R. Cocker III, Georgios Karavalakis, Akua Asa-Awuku, University of California, Riverside
Abstract Number: 1580 Working Group: Combustion
Abstract GDI technology has become the preferred standard to PFI engines in the US and European markets due to its increased specific output and improved fuel economy. GDI vehicles have displayed increased PM emissions, meaning manufacturers of GDI engines may have difficulty meeting the new two phase LEV III PM Standard set at 3 mg/mile by 2017, and 1 mg/mile by 2025. One measure to meet the strict PM emissions standards is utilizing alternative fuel formulations (i.e., high ethanol blends). Currently commercial gasoline blends contain 10% ethanol but previous vehicle studies evaluating the effects of additional ethanol in fuels have found reductions in PM formation, however, the secondary aerosol formation is not understood.
Many previous studies have explored the secondary formation from vehicle exhaust in a clean chamber environment, however, simulating a dirtier urban environment is much more difficult. To execute this, an anthropogenic reactive organic gas (ROG) surrogate was designed to mimic the LA Basin. Emissions data was lumped into categories, and in each category species were weighted by abundance. The surrogate was designed to provide a base chemical reactivity while forming a minimal amount of SOA mass. The surrogate has been utilized in many previous studies at UCR, exploring ozone incremental reacting and SOA formation from single compound experiments, however this is the first study using the surrogate with a complex vehicle exhaust mixture. The goal of the surrogate mixture is to control the gas-phase chemical environment within the chamber system enabling one to explore SOA formation from the mixture.
For this study, the SOA and ozone forming potential for one FFV-GDI’s was analyzed. The vehicle were operated on four different fuels with varying ethanol content (E10, E10 high aromatic, E30, and E78). The vehicles were tested on a cold and hot start, LA-92 driving cycle, both in triplicate. The exhaust was measured to certification standards, and subsequently collected in CE-CERT’s 30m3 Mobile Atmospheric Chamber (MACh) for the entirety of the driving cycle. The emissions were then photochemically aged and real-time particle and gaseous phase measurements were analyzed. Particle instruments include an SMPS, HR-ToF-AMS, VTDMA, and APM. One test in each subset analyzed the secondary aerosol formation of the vehicle exhaust alone. The other two tests, included 1 ppmV of the ROG surrogate in addition to the vehicle exhaust. Results explore secondary aerosol differences due to varying ethanol content, as well as variations due to driving conditions in a simulated anthropogenic environment.