A study of the viscosity-temperature relationship of synthetic lubricants

Various workers have developed different viscosity -temperature relationships for fluids for many years. These relationships are suitable for a narrow temperature range, but they are unsuitable over the wide temperature ranges of synthetic lubricants. This paper describes a modified ASTM 0341 viscosity-temperature relationship developed by a least-squares treatment of large amount of available experimental viscosity data for synthetic lubricants. The modified relationship reads: . The relationship can adequately describe viscosity-temperature characteristics of synthetic lubricants over a wide temperature range. The relationship was examined for various synthetic lubricants. It was found capable of correlating the available experimental viscosity data with an average absolute error of less than 2% between calculated values and experimentally determined values over the temperature ranges studied for 14 synthetic lubricants.