Analysis of the results from a goniometer and tribotester of a diamond derivative coating on the first piston ring of an internal combustion engine

Abstract

The elements creating friction pairs are described to be very difficult in terms of determining all the optimal parameters. The present research on the stability of friction pairs is focused on the surface and the top layer of the surface. The main goal is to find new design solutions and materials which would allow the vehicle to cover a lot of kilometres before the main repair of the combustion engine. The biggest structural difficulties are noticeable in friction pairs where a sliding and returning motion can be observed, which is connected with the sealing function. A typical example of such a pair is that of the piston ring-cylinder. Engineers are working on defining an additional factor that would be able to reduce the tangential force by reducing the friction coefficient in the elements of the friction pair. The molecular structure and nature of the bonds between the molecules present in the material suggest that the free surface energy may be such a factor, because it determines the tribological properties of the material, which is reflected in the stability of the units. The work performs an analysis of the results of investigations carried out by means of a goniometer in the presence of water and diodomethane, which made it possible to measure the wetting drops on the surface, owing to which the surface free energy (SFE) could be calculated. This work will include a study of the energy state of the surface of piston rings with a coating containing a diamond powder. After the analysis of the collected measurements, a conclusion regarding the potential relationship between the free surface energy and the material wear will be developed.