Modeling and simulation of oil transport and transformation for studying piston deposits

Abstract

The formation of carbonaceous engine deposits is a long standing and well documented phenomenon limiting the lifetime of diesel engines. Carbon remnants coat the surfaces of the combustion chamber, piston, and valves. As piston deposits thicken, they increase the risk of a power cylinder seizure. More restrictive emission standards require careful power cylinder design to control piston deposits, specifically in the top land and top ring groove. Experimental studies on heavy duty diesel engines show a non-uniform pattern of carbon deposits on the top land. The degradation of engine lubricant is typically understood to be source of deposits. A theoretical study was begun to understand the effects of harsh operating environment that leads to degradation. A thin-film, transient, mass and heat transfer simulation of the top land was formulated, which utilizes the results of a combustion chamber CFD simulation as input data.