MODELING AND SIMULATION OF TRANSIENT SHEAR HEATING EFFECTS IN EHL OF PISTON SKIRTS DURING

Abstract

Presence of fully established EHL film effectively prevents adhesive wear and reduces friction between piston assembly and cylinder liner under engine normal operating conditions. Absence of the same during initial start up, does affects the lubrication mechanism and may cause significant reduction in engine predicted design life. A comprehensive mathematical model representing EHL phenomenon may lead towards a viable solution of above stated problem. Earlier studies modeled EHL phenomenon but under ideal conditions. This research aims to mathematical model transient piston skirt EHL phenomenon by using 2-D Reynolds equation ( for pressure profiles generation on piston skirt) and 2-D Transient Thermal Energy equation ( for temperature distributions within oil film) during initial engine start up conditions with particular emphasis on shear heating and temperature rise of lubricant film between piston and liner, its effects on the viscosity of lubricant and oil film thickness which, in turn, affects load carrying capacity of the lubricant. This research will analyze temperature dependent viscosity, its variation and effects on EHL. This research will also undertake parametric studies on the subject after duly incorporating pressure-temperature- viscosity relationship in the developed model.