Impacts of Mid-level Biofuel Content in Gasoline on SIDI Engine-Out and Tailpipe Particulate Matter Emissions: Preprint

Research output: Contribution to conferencePaper


The influences of ethanol and iso-butanol blended with gasoline on engine-out and post Three-Way Catalyst (TWC) particle size distribution and number concentration were studied using a GM 2.0L turbocharged Spark Ignition Direct Injection (SIDI) engine. The engine was operated using the production ECU with a dynamometer controlling the engine speed and the accelerator pedal position controllingthe engine load. A TSI Fast Mobility Particle Sizer (FMPS) spectrometer was used to measure the particle size distribution in the range from 5.6 to 560 nm with a sampling rate of 1 Hz. US federal certification gasoline (E0), two ethanol-blended fuels (E10 and E20), and 11.7% iso-butanol blended fuel (BU12) were tested. Measurements were conducted at ten selected steady-state engine operationconditions. Bi-modal particle size distributions were observed for all operating conditions with peak values at particle sizes of 10 nm and 70 nm. Idle and low speed / low load conditions emitted higher total particle numbers than other operating conditions. At idle, the engine-out Particulate Matter (PM) emissions were dominated by nucleation mode particles, and the production TWC reduced thesenucleation mode particles by more than 50%, while leaving the accumulation mode particle distribution unchanged. At engine load higher than 6 bar NMEP, accumulation mode particles dominated the engine-out particle emissions and the TWC had little effect. Compared to the baseline gasoline (E0), E10 does not significantly change PM emissions, while E20 and BU12 both reduce PM emissions under theconditions studied. Iso-butanol was observed to impact PM emissions more than ethanol, with up to 50% reductions at some conditions. In this paper, the issues related to PM measurement using FMPS are also discussed. While some uncertainties are due to engine variation, the FMPS must be operated under careful maintenance procedures in order to achieve repeatable measurement results.
Original languageAmerican English
Number of pages23
StatePublished - 2011
EventSAE 2010 Powertrains, Fuels and Lubricants Meeting - San Diego, California
Duration: 25 Oct 201027 Oct 2010


ConferenceSAE 2010 Powertrains, Fuels and Lubricants Meeting
CitySan Diego, California

NREL Publication Number

  • NREL/CP-5400-49311


  • emissions
  • engine performance
  • ethanol
  • gasoline blends
  • iso-butanol blended fuel


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