Abstract
Most efthe lubricating oil from Internal Combustion Engine (ICE) is lost through piston rings. Hence, in order to optimally reduce ICE oil consumption, a better insight into tribology of the ring pack is required. This can only be achieved by an inwroved characterization of the lubricant behaviour within the opelating environment of the engine. In The present ieork, an optical tcchnique using laser- induced fluorescence was employed to measure oil film thickness within the ring pack. The experiment was conducted on a Phaser 1000 Series engine, whereby optical access to the ring pack was achieved by a fused silica-window positioned flush with the inside surface of the liner. It has been observed that for a given engine operating condition there are significant cyclic variations in oil film thickness. For example. for an engine torque of Nm at 1250 revs/min, oil film thickness around rhe top ring varied by up to 230% between two consecutive strokes. The scune trend was obsen'edfor all other rings whereby compression rings were lubricated by a Illickerfibn during expansion and intake s!rokes than during compression and exhaust, whilst it was rhe opposite for the Oil control ring. Furthermore, oil filnl Thickness under compression rings was observed to be virtually unaffected by increasing engine speed and load. On the other hand, lower engine speeds and torque yielded Thicker lubrication films on the oil control ring, inrespecr of rhe fact That the lubrication regime was hydrodynamic. This is explained by the decrease in oil viscosity due to the observed increase in Oil temperature within the ring pack as engine speed was increased. Generally, the largest net oil flows occurred during the power cycle to indicate the dominance of the scrapping action of rhe second compression and the oil control rings. Although the results of Ellis study have shed some new lights in the understanding of lubricant behaviour within the ring pack under operating environment of the engine, more work is still required to improve the in-situ calibration adopted in this experiment or relate the fluorescence intensity and oiifilm thickness. While it was anticipated that the grooves in the calibration cell will be completely filled with oil, the same did not happen all the time as the filling of grooves was stochastic in nature to call for numerous preliminary attempts before any reliable measurement could be made
Recommended Citation
Mshoro, I. (1998). A STUDY ON RING PACK LUBRICATION IN INTERNAL COMBUSTION ENGINE. Tanzania Journal of Engineering and Technology (TJET), 22(2), 231-246. https://doi.org/https://doi.org/10.52339/tjet.v22i2.281
Publisher Name
University of Dar es Salaam