Proposing new hybrid nano-engine oil for lubrication of internal combustion engines: Preventing cold start engine damages and saving energy

Abstract

In this paper, viscosity of SAE 5W50 oil enriched by MWCNT and ZnO nanoparticles with combination ratio of 1:4 is experimentally investigated in solid volume fractions of 0.05, 0.1, 0.25, 0.5, 0.75, and 1% and temperature range of 5 to 55 ˚C. It is done with the aim of feasibility study on achieving a modified nano-engine oil that can minimize cold start engine damages using nanoparticles. According to results, produced nano oil with concentrations less than 0.25% selected as modified engine oil. Almost 9% reduction in viscosity of nano-oil with solid volume fraction of 0.05% compared to ordinary engine oil in 5 °C and shear rate of 666.5 (1/sec) was one of the very interesting results of this investigation which makes pumping easier and oil will enter the lubrication cycle faster and this minimizes cold start damages. Moreover, Presence of nanoparticles improves heat transfer from engine parts. The result showed that in temperature range of 35–55 °C, and solid volume fractions less than 0.25%, our proposed nano-oil is more appropriate for high temperature usage too, because of lower dependency of its viscosity to temperature in comparison to pure 5W50 engine oil. A mathematical correlation was proposed to predict viscosity of nano-engine oils used in this research. R-Squared = 0.9685 of this correlation shows its high accuracy.