Differentiation of lubricant degradation in the piston ring groove and crown land by multivariate data analysis

Abstract

The degradation of a ‘bridged’ set of three lubricant formulations using different base oils and additive packs was investigated at two positions on the piston of an operating petrol engine. Chemical and physical analysis of the lubricants obtained from the two sampling positions generated two corresponding databases for each position. Principal component and partial least-squares—discriminant data analyses of these databases demonstrate that the chemical and physical degradation of lubricants is dominated by different components of their formulation, the base oil and the additive pack at the different sampling points on the piston.