The Effect of Lubricant Viscosity-Temperature Characteristics on the Performance of Plain Journal Bearings

Experimental and analytical results of bearing friction loss, operating temperature, and oil gap thickness are presented comparing performance characteristics of bearings operating with the different lubricants. The lubricants were blended using a variety of mineral and synthetic base stocks to achieve a range of viscosity-temperature characteristics. The results show that the test bearings running with higher viscosity index (VI) lubricants generated slightly lower bearing surface temperatures than those generated using a low VI lubricant. The high VI lubricant also reduced the total power losses by up to 10%. These gains are achieved with little or no change in the minimum oil film thickness.