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Ethanol fuels reduce emissions of a flex-fuel vehicles

Ethanol fuels reduce emissions of a flex-fuel vehicles

Finnish Meteorological institute conducted a study on how ethanol content of flex-fuel vehicle influences exhaust emissions.

Results of this measurement campaign indicate that alcohol fuels (E85, E100) significantly reduce both primary particulate emissions as well as subsequent secondary aerosol formation in the atmosphere when compared emissions of gasoline fuels.

In this study emissions were measured for flex-fuel vehicle using different ethanol content fuels (E10, E85, E100). Results indicate that when the ethanol content of the fuel increased, the emissions of gaseous organic compounds increased whereas the amount of aromatic compounds such as benzene and toluene decreased. Particulate emissions were largest for E10 fuel. "A clear decrease in both primary and secondary particle emissions were observed as the amount of alcohol in the fuel increased" summarizes FMI researcher Hilkka Timonen.

Air quality is influenced also by secondary particulate matter emissions

Primary particulate emissions typically consists of soot and organic compounds whereas secondary aerosol formed from gaseous compounds typically consist of organic compounds, sulfate, nitrate and ammonium. Both, primary emissions and secondary aerosol emitted by vehicles have an influence to air quality in urban areas.

"Emissions limits set for light-duty vehicles only apply to primary particulate emissions. However, it is important to understand the secondary aerosol formation and its influence to air quality, in order to take it into account when new emission limits for vehicles are set and thus improve air quality in tightly populated urban areas." Says research scientist Hilkka Timonen.  

Emissions were characterized during a New European Driving Cycle (NEDC) using a comprehensive set-up of high time-resolution instruments. A detailed chemical composition of the exhaust particulate matter (PM) was studied using a soot particle aerosol mass spectrometer (SP-AMS), and secondary aerosol formation was studied using a potential aerosol mass (PAM) chamber.

Study was conducted in co-operation with VTT and Tampere University of Technology at the VTT engine laboratory. This research was part of the Cluster for Energy and Environment (CLEEN Ltd); Measurement, Monitoring and Environmental Assessment (MMEA), work package 4.5.2. Car measurements belonged to Annex 44 of Advanced Motor Fuels (AMF) Technology Collaboration Programme of the International Energy Agency (IEA).

For more information:

Researcher Hilkka Timonen, Hilkka.timonen@fmi.fi

Timonen, H., Karjalainen, P., Saukko, E., Saarikoski, S., Aakko-Saksa, P., Simonen, P., Murtonen, T., Dal Maso, M., Kuuluvainen, H., Bloss, M., Ahlberg, E., Svenningsson, B., Pagels, J., Brune, W. H., Keskinen, J., Worsnop, D. R., Hillamo, R., and Rönkkö, T.: Influence of fuel ethanol content on primary emissions and secondary aerosol formation potential for a modern flex-fuel gasoline vehicle, Atmos. Chem. Phys., 17, 5311-5329, doi:10.5194/acp-17-5311-2017, 2017.


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