The crosshead bearings in large two-stroke diesel engines operate under severe lubrication conditions, because the bearings oscillate within a small angle at a low speed and are subject to a high specific load. Crosshead bearings have several axial oil-grooves on the loaded surface to promote oil film exchange with bearing oscillation. However, because the development of a thick oil film by hydrodynamic action is impaired by these oil grooves, the bearings become prone to damage by seizure and fatigue cracking. This manuscript describes the lubrication characteristics of the crosshead bearings. A decrease in the clearance ratio is generally effective at enhancing the squeeze action on the entirety of the bearing pads. However, this degrades the formation of an adequate wedge film and reduces the load carrying capacity. Incorporating oil-grooves with tapered geometry and an externally pressurized lubrication system promotes a thicker oil film, achieving a significant enhancement of the load carrying capacity. The aluminum-tin bearing coated with a tin-copper overlay improves running-in properties, enhancing the load carrying capacity.
