Dynamic Viscosity-Temperature Characteristics and Models of Various Lubricating Oils

Background: The dynamic viscosity-temperature characteristics of lubricants are the main factors used to determine the oil film thickness and carrying capacity. There are few studies on the factors affecting the dynamic viscosity-temperature characteristics of lubricating oils and the dynamic viscosity-temperature model. Objective: This research aims to analyse the influences of lubricating oil type and initial kinematic viscosity on dynamic viscosity-temperature characteristics and present a new dynamic viscositytemperature model. Methods: The characteristic curves of dynamic viscosity versus temperature of polyol ester oil, paraffinic mineral oil, and five types of PAO (poly α-olefin) oils with different initial viscosities were obtained by using a kinematic viscosity test device and a density test device. The influences of lubricating oil type and lubricating oil viscosity on dynamic viscosity-temperature characteristics were analysed. A new dynamic viscosity-temperature model was presented based on our patent technology and repeated verification. Results: Viscosity-temperature curves of three different types of lubricating oils and viscositytemperature curves of PAO oils with different initial kinematic viscosities were obtained. A new dynamic viscosity-temperature model η = A x e^(-T/n) + η0 was proposed. Conclusion: The dynamic viscosity-temperature characteristics of lubricating oils are not only determined by the type of oils but also determined by the initial kinematic viscosity. The variation of dynamic viscosity of lubricating oils with temperature in the scope of -40~110°C can be described by the following viscosity-temperature model: η = A x exp ^(-T/n) + η0 which can be used in a wider temperature range than the existing models.