THE PROFILE DEVELOPMENT OF A TWIN-LAND OIL-CONTROL RING DURING RUNNING-IN

This paper presents experimental results of motored engine tests on th e wear and profile development of a twin-land oil-control ring. It is shown that the roughness height of the plateau honed liner decreases d uring running-in, indicating that the deeper grooves remain unaffected . The piston lands are much smoother, and do not show a significant ov erall change in surface roughness. The profile development results are compared with computer predictions in order to verify the theoretical modeling. It is indicated that the worn land profiles remain tapered, with an inclination resembling the twist angle of the ring. However, there remains a difference in the experimental and the numerically pre dicted land inclinations. This is probably due to the piston tilt, whi ch was not included in the theoretical model.