Effects of Ethanol Evaporative Cooling on Particulate Number Emissions in GDI Engines
Name
4-sae 2018-01-0360; etOH effet on PMI-preprint.pdf
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2.16 MB
Format
Adobe PDF
Checksum (MD5)
14fce8655d581a43ab26890e84b4aebc
Author(s)
Chen, Yu
Zhang, Yihao
Cheng, Wai K.
Date Issued
April 2018
Journal
SAE Technical Papers
Publisher
SAE International
Citation
Chen, Yu, Yihao Zhang, Y., and Wai K. Cheng. “Effects of Ethanol Evaporative Cooling on Particulate Number Emissions in GDI Engines,” SAE Technical Paper 2018-01-0360, 2018.
Version
Author's final manuscript
Abstract
The spark ignition engine particulate number (PN) emissions have been correlated to a particulate matter index (PMI) in the literature. The PMI value addresses the fuel effect on PN emission through the individual fuel species reactivity and vapor pressure. The latter quantity is used to account for the propensity of the non-volatile fuel components to survive to the later part of the combustion event as wall liquid films, which serve as sources for particulate emission. The PMI, however, does not encompass the suppression of vaporization by the evaporative cooling of fuel components, such as ethanol, that have high latent heat of vaporization. This paper assesses this evaporative cooling effect on PN emissions by measurements in a GDI engine operating with a base gasoline which does not contain oxygenate, with a blend of the gasoline and ethanol, and with a blend of the gasoline, ethanol, and a hydrocarbon additive so that the blend has the same PMI as the original gasoline. As such, the dilution and the evaporative cooling effects of the ethanol could be separated. Measurements have also been done with methanol and MTBE. The results show that evaporative cooling effect can significantly change the PN emission. The extent of the change, however, depends on the details of the operating condition such as injection timing, engine coolant temperature, and load.
MIT Department
Massachusetts Institute of Technology. Research Laboratory of Electronics
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution-Noncommercial-Share Alike
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DOI of Published Version
https://doi.org/10.4271/2018-01-0360
