Accession Number : ADA330105

Title :   Test Method to Evaluate Cylinder Liner-Piston Ring Coatings for Advanced Heat Engines.

Descriptive Note : Technical rept.,

Corporate Author : NATIONAL AERONAUTICS AND SPACE ADMINISTRATION CLEVELAND OH LEWIS RESEARCH CEN TER

Personal Author(s) : Radil, Kevin C.

PDF Url : ADA330105

Report Date : AUG 1997

Pagination or Media Count : 13

Abstract : A tribological test method has been developed to assess candidate high temperature piston ring and cylinder liner coatings for advanced heavy duty diesel engines. A reciprocating test rig is employed to reproduce the boundary lubricated conditions existing at the piston ring-cylinder liner interface during top ring reversal (TRR). The test specimens are fabricated from commercially available piston rings and cylinder liners to facilitate direct comparisons with current diesel engines. A data acquisition system is used to collect coefficient of friction values. Coating performance is based upon calculated volumetric wear factors of the ring and liner as well as the friction coefficient. Baseline tests were conducted with chrome coated piston rings sliding on pearlitic gray cast iron cylinder liners while in the presence of a fully formulated engine oil. Friction measurements exhibited excellent repeatability throughout the entire test with average values ranging from 0.079 to 0.082. The mean of the ring and liner wear factors was 7.28 x 10 to the minus 10th power mm 3/N*m and 2.62xl0 to the minus 8th power mm3/N*m, respectfully and are in good agreement with values reported in the literature. These results indicate that the test method is capable of reproducing TRR conditions at the ring-liner interface of a diesel engine.

Descriptors :   *DIESEL ENGINES, *TEST METHODS, *PROTECTIVE COATINGS, LININGS, WEAR, FRICTION, TRIBOLOGY, LUBRICATING FILMS, PISTON RINGS.

Subject Categories : Coatings, Colorants and Finishes
      Lubricants and Hydraulic Fluids

Distribution Statement : APPROVED FOR PUBLIC RELEASE