Emissions and fuel economy of a large volume prechamber, fuel injected, stratified charge engine with gasoline and a gasoline/20% methanol blend are measured. The engine is a modified CFR cetane test engine operating with MBT spark timing and 8. 4:1 compression ratio. The effect of both prechamber and main chamber mixture ratio on engine operation and emissions is investigated. Lowest overall emissions are achieved simultaneously with low fuel consumption at a prechamber equivalence ratio of 1. 10. The stratified charge engine when operated on the gasoline/methanol blend shows significant improvement over gasoline in NO emissions but also with higher exhaust CO and HC. Fuel economy is not significantly different for the two fuels so long as the prechamber is not overly rich. The interpretation of the HC emissions measurements is aided by a study of quenching distances of methanol and methanol blends. A constant volume, flanged electrode test bomb is used to measure quenching distances of reactive gas mixtures. Experiments are performed with methane, methanol, iso-octane and iso-octane/methanol blends over a range of equivalence ratios for several mixture initial temperatures and pressures. The fuel blends are found to have larger quenching distances than either pure fuel which is consistent with the observation of slightly higher HC emissions in the engine study when using the methanol blend

Media Info

  • Pagination: p. 115-121

Subject/Index Terms

Filing Info

  • Accession Number: 00153233
  • Record Type: Publication
  • Source Agency: Engineering Index
  • Report/Paper Numbers: SAE 769021 Proceeding
  • Files: TRIS
  • Created Date: Oct 29 1977 12:00AM