Analysis of big-end bearing having non-Newtonian fluids

Abstract

This paper deals with analysis of a big-end bearing of an I.C. engine having non-Newtonian lubricants. To account for the variation of viscosity across the film thickness, the three dimensional momentum and continuity equations of fluid flow have been used in the analysis instead of the traditional Reynolds equation. The bearing center motion trajectory, minimum film thickness and peak pressure results have been obtained for a non-Newtonian fluid whose constitutive equations are defined by a cubic shear stress law. There are also commercial oils (non-Newtonian) whose viscosity variation as a function of shear rate may be expressed by fitting a polynomial between the known viscosity and shear rate values. In this paper, it is named as 'curve-fit model.' For a finite crank rotation of the same big-end bearing, the values of ε, β (coordinates of bearing center) have also been obtained with such a commercial oil (SAE 10 W-40 with styrene-ester as VI, C-2) by wing curve fit model.