Rheological Properties of Engine Oil with Nano-Additives Based on MoS₂ Materials

To enhance oil's tribological and rheological properties, various nano-additives are used. An example of such a nano-additive is nanosized molybdenum disulfide (MoS₂). Due to its unique properties, MoS₂-based materials used as lubricants have attracted significant attention. In our previous work, we developed a novel, scalable, and low-cost method for MoS₂-based materials production using an impinging jet reactor. Hybrid nanostructures based on MoS₂ and carbon nanomaterials (MoS₂/CNMs) decreased the friction factor of the base oil. In the present study, a mathematical model that accounts for the viscous heating effects in rheograms was formulated. The model was used to interpret the results of rheological measurements conducted for the base oil 10W40 and its mixtures with different nanosized lubricant additives. The model of the non-isothermal Couette flow allowed us to correct the rheograms of the engine oils in the region of high shear rates where viscous heating effects become significant. The temperature correlations for the consistency and flow behavior indexes were proposed. The nanohybrid suspensions of MoS₂ in the base oil were found to have the lowest apparent viscosity at low temperatures, typical for the cold engine startup.