Optical Ways to Improve the Tribological System Piston - Ring - Liner

The reliable function of the system piston - piston ring -liner depends strongly on the correct quantity of oil. A balance between the sufficient oil offer and minimum emission is to be found. For this system numerous computation programs exist however their results strongly depends from the boundary conditions. To assist in the understanding of this system it is to be used necessarily optical research methods. So that the lubricating film at the piston and at the piston rings can be examined, a cylinder of an engine had to be completely made of glass. The used glass must have the wetting characteristics of grey cast iron, so that the results are transferable. The used tracers to visualize the oil may not change the characteristics of the oil. Different photograph procedures were necessary, in order to identify the fundamental presence of oil and the bearing oil film. In this paper the test set-ups and results are described.

The results show the change lubricating film at the piston surface over the stroke under different conditions. The influence of the piston rings and the oil transport ways in the ring package is described.