CHARACTERIZATION OF THE LEAN MISFIRE LIMIT

Cycle by cycle variations in combustion are investigated as a means to characterize the lean misfire limit of a spark ignited, internal combustion engine. The cyclic variations are represented as parameters of the cylinder pressure versus crankangle curves. The specific parameters investigated are peak pressure, maximum rate of pressure rise, crankangle of maximum pressure, crankangle of maximum rate of rise, indicated mean effective pressure, and area of the pressure curve. The variations are statistically analyzed on a digital computer. Exhaust gas analysis is performed to determine the correlation between the misfire limit and emissions of hydrocarbons, carbon dioxide, carbon monoxide, nitric oxide, and formaldehyde. Imep and area variations are found to be the most promising as an indicator of the lean misfire limit. As the equivalence ratio decreases from stoichiometric, the variations stay constant, until a sharp linear increase is achieved. Correlation with hydrocarbon emissions shows a strong combustion change occurs at this point of rapid variation increase. This point is adopted as the definition of the lean misfire limit.

• Supplemental Notes:
  • Prepared for the SAE meeting February 27-March 3, 1978.
• Corporate Authors:

  Society of Automotive Engineers (SAE)

  400 Commonwealth Drive
  Warrendale, PA  United States  15096
• Authors:
  • Shiomoto, G H
  • SAWYER, R F
  • Kelly, B D
• Publication Date: 1978

Media Info

• Features: References;
• Pagination: 13 p.

Subject/Index Terms

• TRT Terms: Air pollution; Biodegradability; Carbon dioxide; Carbon monoxide; Combustion; Control; Correlation analysis; Exhaust gases; Formaldehyde; Fuel conservation; Hydrocarbons; Induction heating; Internal combustion engines; Performance; Pressure; Variables; Vehicle power plants
• Uncontrolled Terms: Cylinders
• Old TRIS Terms: Automobile engines; Cycles; Variations
• Subject Areas: Data and Information Technology; Energy; Highways; Safety and Human Factors; Vehicles and Equipment;

Filing Info

• Accession Number: 00177343
• Record Type: Publication
• Source Agency: Engineering Index
• Report/Paper Numbers: SAE 780235 Proceeding
• Files: TRIS
• Created Date: Sep 27 1978 12:00AM