LASER SHADOWGRAPHIC ANALYSIS OF KNOCKING IN S.I. ENGINE

High-speed laser shadowgraph cinematography synchronized with measurement of the pressure in the combustion chamber was employed in order to observe the location and magnitude of autoignition that causes cylinder gas oscillation. The use of a laser light source enabled the exposure time to be set at 0.8 microseconds with a high film speed of 30,000 f.p.s.. An image processing system was also used to determine the exact location of autoignited gases. The results clarified that the location of autoignition varied cycle-by-cycle. In some cycles it occurred in the vicinity of the cylinder wall, in some cycles it originated in the middle of the end gas and just in front of the propagating flame. It was also made clear that the occurrence of autoignition at a traceknock spark timing did not always bring about an oscillation in the chamber gases in case where the speed of the autoignited gas did not exceed a certain value.

• Supplemental Notes:
  • Twentieth FISITA Congress, (SAE P-143), The Automotive Future, Volume 1, Austria, 6-11 May 1984.
• Corporate Authors:

  Society of Automotive Engineers (SAE)

  400 Commonwealth Drive
  Warrendale, PA  United States  15096
• Authors:
  • Nakagawa, Y
  • Takagi, Y
  • Itoh, T
  • Iijima, T
• Publication Date: 1984-5

Media Info

• Features: Figures; References; Tables;
• Pagination: p. 1.9
• Serial:
  • Publication of: Society of Automotive Engineers, Incorporated
  • Publisher: Society of Automotive Engineers (SAE)

Subject/Index Terms

• TRT Terms: Engine knock; Lasers; Photography; Spark ignition engines
• Old TRIS Terms: Laser applications; Shadow photography
• Subject Areas: Safety and Human Factors;

Filing Info

• Accession Number: 00392463
• Record Type: Publication
• Source Agency: National Highway Traffic Safety Administration
• Report/Paper Numbers: SAE 845001, HS-037 419
• Files: HSL, USDOT
• Created Date: Feb 28 1985 12:00AM