The influence of driving procedures and extraneous car noise on perception of engine knock has been studied with a random sample of 1975 and 1977 U.S. and imported cars, all but one with automatic transmissions. Test fuels were blended from unleaded, commercial gasolines of low, intermediate, and high octane quality; they provided a range of Research Octane Number (RON) from 81 to 100. Year-to-year changes in reports of knock by both customers and raters and changes in octane requirements were also considered. Customers generally accelerated cars less vigorously and tended to perceive knock less often than raters. In cars that had maximum octane requirements at part-throttle, customers perceived knock about as frequently as raters. Octane requirements, as determined by raters, were reduced by about 2 RON's when the car radio was turned on and the windows closed. Both customers and raters reported more knock with 1975-1977 model cars than with earlier models. Since 1975, octane requirements of certain car models tended to be adjusted to the octane quality of available gasoline. More information is needed to determine whether the differences between customer and rater perception of knock change significantly from winter to summer.

  • Supplemental Notes:
    • Presented at the SAE Congress and Exposition, Detroit, 27 February-3 March 1978.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • Bettoney, W W
    • Rogers Jr, J D
    • Riegel, J E
  • Publication Date: 1978

Media Info

  • Features: References;
  • Pagination: 32 p.

Subject/Index Terms

Filing Info

  • Accession Number: 00395650
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: SAE 780323, HS-025 420U
  • Files: HSL, USDOT
  • Created Date: Jun 30 1985 12:00AM