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A unique combination of boundary lubricant and surfactant chemistries has produced significant benefits in ring and bearing wear control. This chemistry is added as an engine treatment to current quality engine lubricants. Microscopic wear studies employing radioactive tracer and metal surface analysis techniques have helped define optimum chemistry for enhanced bearing and ring wear control in a running engine. These studies have also served to further our understanding of the wear protection mechanism. Results from macroscopic engine wear studies, carried out in Sequence IIIE engines/stands using modified ASTM IIIE protocols, paralleled data obtained from the radioactive wear studies. They confirmed the positive wear protection benefits of this unique chemistry. Vehicle emission evaluations using the Federal Test Procedure (FTP) for light duty vehicles with this unique chemistry showed no detrimental effects either as added pollutants or catalyst degradation.

A mechanism was proposed in SAE Paper #941983, (October, 1994) to explain why “Unique Boundary Chemistry” (UBC) described in said paper (1) required an extended conditioning period for its full antiwear benefits to be realized and (2) why the UBC Chemistry produced a strong antiwear carryover effect, even after relatively short exposure to the engine. This paper will document and discuss results from several metal surface studies employing a variety of metal surface analysis techniques (XPS, Profilometry, and AFM) to support various aspects of the earlier proposed antiwear mechanism. These surface analysis studies were carried out with pertinent boundary lubricated parts from (a) bench tests, (b) engines tested under modified protocol Sequence IIIE conditions described in SAE Paper 941983 and (c) standard ASTM Sequence IIIE and VE tests exposed to the UBC Chemistry.