Analysis of the Operational Wear of the Combustion Engine Piston Pin

This article presents the results of research into the causes of the wear of the piston pin mounted in piston bosses by means of a hinge joint and in the connecting rod small end by means of the thermocompression bond. Changes in geometry and in the pin-top surface structure, which are caused by the mutual influence of the mating surfaces in variable lubrication conditions, are presented. The progress of scuffing as a result of insufficient lubrication of the mating elements or oil film breaking is demonstrated. The state of destruction was confirmed by the results of surface roughness measurements showing the formation of build-ups. The loss of the thermocompression bond surface, caused by the penetration of sintered engine oil fractions containing biofuel additive components and spent engine oil improver packages, was noted. The progressing forms of wear are the cause of engine failures due to the pin movement towards the cylinder wall, and due to boss breakage in the piston.

Automated summary

This article presents the causes of wear in piston pin and connecting rod small end due to hinge joint and thermocompression bond respectively. It discusses the changes in geometry and pin-top surface caused by the influence of mating surfaces in different lubrication conditions. The progression of scuffing due to insufficient lubrication or oil film breaking is demonstrated, along with the confirmation of wear through surface roughness measurements. The loss of thermocompression bond surface is noted, caused by the penetration of sintered engine oil with biofuel additive components and spent engine oil improver packages. The progressing wear forms are leading to engine failures.