A new method for determining antioxidant capacity of lubricants was used for monitoring initial antioxidant capacities in various engine oils and antioxidant decay during laboratory and fleet testing of selected oils. The method involves the quantitative determination of antioxidant species present in oil by titration with peroxy radicals formed at a known and constant rate from the decomposition of a free radical initiator at 60 degrees C in the presence of oxygen. A general correlation between initial antioxidant capacities of engine oils and an oil thickening characteristic from Sequence IIIC testing was obtained for engine oils containing conventional additive technologies. Monitoring the decay of antioxidant capacity during laboratory beaker, Sequence IIIC, and long drain fleet testing provided information on lubricant oxidative deterioration in the early period of testing when no other performance characteristics showed appreciable changes. New insights into the nature of engine oils' oxidative deterioration, as a function of antioxidant type and concentration, base oil type, and test or engine severity, were obtained. This was achieved by combining results derived from the new method with those obtained from conventional analysis.

  • Availability:
  • Supplemental Notes:
    • Presented at SAE International Fuels and Lubricants Meeting, Toronto, 13-16 November 1978.
  • Corporate Authors:

    Society of Automotive Engineers (SAE)

    400 Commonwealth Drive
    Warrendale, PA  United States  15096
  • Authors:
    • Korcek, S
    • Mahoney, L R
    • JOHNSON, M D
    • Hoffmann, S
  • Publication Date: 1978

Media Info

Subject/Index Terms

Filing Info

  • Accession Number: 00399215
  • Record Type: Publication
  • Source Agency: National Highway Traffic Safety Administration
  • Report/Paper Numbers: SAE 780955, HS-025 901U
  • Files: HSL, USDOT
  • Created Date: Oct 31 1985 12:00AM