THE EFFECT OF MIXING RATE, END OF INJECTION, AND SAC VOLUME ON HYDROCARBON EMISSIONS FROM A D.I. DIESEL ENGINE

Some results of a systematic analysis of important sources of hydrocarbon emissions from a direct injection diesel engine are presented. The following sources are considered and investigated: (1) local overmixing, (2) poor end of injection, (3) fuel emptying from sac volume. The analysis uses systematic engine experiments and an existing two-dimensional thick evaporating spray model to determine the contribution of various hydrocarbon sources to the total hydrocarbon emissions in the exhaust. The results show that at idle and light load conditions, local overmixing is the major source of hydrocarbon emissions. The amount of fuel overmixed is directly controlled by mixing rate, ignition delay, and the lean limit of combustion. Mixing rate calculations show that the injection rate shape and nozzle geometry are more important than the physical properties of the fuel in determining the amount of fuel overmixed. The results also show that for a low emission engine using timing advance at light loads for overmixing control, poor end of injection and fuel emptying from the sac volume can be important sources of hydrocarbons. The characterization of these sources and their effect on fuel evaporation and hydrocarbon emissions are discussed.

  • Supplemental Notes:
    • A Worldwide View of Diesel Combustion Emissions and Analysis, P-130. International Off-Highway Meeting and Exposition Milwaukee, Wisconsin, September 12-15, 1983.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • YU, R C
    • Kuo, T-W
    • SHAHED, S M
    • Chang, T W
  • Publication Date: 1983-9

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00382403
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Files: HSL, USDOT
  • Created Date: Mar 30 1984 12:00AM