Effects of ethanol and aromatic compositions on regulated and unregulated emissions of E10-fuelled China-6 compliant gasoline direct injection vehicles

This research examined the effects of ethanol and aromatic compositions in E10 match-blends on the exhaust regulated, greenhouse gases, and unregulated toxic emissions of five China-6 compliant gasoline direct injection vehicles at room and low ambient temperatures. Emissions of a China-6 compliant gasoline and four E10 match-blends having roughly the same total aromatic concentration but containing different aromatic compositions were measured using Fourier transform infrared spectrometer, gas chromatogram-mass spectrometer, and high-performance liquid chromatogram. The results show that ethanol content decreases the fleet-averaged regulated gas and particulate mass (PM) emissions and increases the particulate number (PN), benzene, and toluene emissions. As the aromatic compositions in E10 match-blends shift from toluene to C8 and C9 aromatics, PM and PN emissions significantly increase. The low temperature leads to higher emission factors than the room temperature, especially the emissions from the fuel with more toluene content. C8 and C9 aromatics are found to have larger impacts on PM emissions but smaller impacts on PN emissions than the C10 and C10+ aromatics. It is noticed that benzene emissions at the low temperature heavily depend on the fuel toluene concentration.