Abstract
In lubricated surfaces of reciprocating engine components, such as piston rings and cylinder liners in marine diesel engines, the effects of surface texturing on lubrication characteristics are considered to be important. In addition, measurement of the electrical contact resistance between the lubricated surfaces of reciprocating components is thought to be effective for lubrication condition monitoring, particularly the existence or absence of oil film. In this study, well-regulated “micro dimples” and “micro grooves” were formed on a flat surface using the method of micro fabrication. A bearing steel (HV760) was used for the specimens with ball-on flat configuration. The friction force, relative movement, and electrical contact resistance between the specimens were measured simultaneously during reciprocation at a stroke of 1 mm under lubricated conditions of 70 and 460 mm2/s oil (non additive mineral oil). The normal load and frequency were varied in the range of 4.9 to 19.6 N, 1 to 5 Hz respectively with comparisons made between specimens with flat surfaces. Furthermore, a direct observation of the contacting surfaces was carried out with a hemispherical sapphire glass using a high speed digital camera. Using these results, the effects of surface texturing of reciprocating component surfaces on the lubrication conditions are discussed.
