Consideration of Test Parameters in Reciprocating Tribometers Used to Replicate Ring-On-Liner Contact

The use of horizontal reciprocating tribometers to model ring-on-liner contact in engines is common practice. The steady reduction of lubricant viscosity to improve fuel economy has produced a consequential reduction in film thicknesses at these interfaces. As a result reciprocating tribometer tests are now more often testing the resultant surface film formed in the contact by the lubricant additive package as opposed to the bulk lubricant. This has made understanding the interlinked nature of the parameters that can be set on the tribometer more essential than previously due to the increasing complexity of the tribochemistry. In this article, the parameters that can be set on these reciprocating tribometers are discussed, how they potentially impact upon the test, the interactions between the parameters and the level of representation of the engine conditions that can be achieved.