Delumping Strategy to Infer Lubrication Reaction Pathways in Internal Combustion Engines

Lubricant reactions in internal combustion engines follow complex reaction pathways, in which oil (hydrocarbons) and additives form protecting films (known as tribofilms) on the surfaces of the cylinder-piston couple. Up-to-date there is not a fundamental model useful to describe the chemistry involved in formation of these tribofilms, and degradation of oils and additives as result of working time of the engine. One of the main problems associated is the impossible measuring of the actual phenomena inside the engine, at working conditions. In order to model formation of tribofilms, starting by lumping two main groups of lubricating molecules, anti-shear and anti-wear, the lumped kinetics model for degradation products was solved, based on actual data collected in commercial engine workshops. Later these two-lump reaction schemes were delumped into two new systems, each one consisting of three lumps, in order to infer lubricant reaction pathways that form tribofilms and degrade lubricants. Distribution of anti-shear and anti-wear lubricants in tribofilms was predicted by simulation of these two delumped schemes.