SOME ENGINE OIL ADDITIVES AND THEIR EFFECTS ON ANTIWEAR FILM FORMATION

Engine oils contain several additives dissolved or dispersed in a hydr ocarbon oil base. Each of these additives are meant to perform one or more functions, which may or may not relate directly to friction and w ear. The performance of additive mixtures, however, cannot usually be predicted in a simple fashion, such as, for example, by a rule-of-mixt ures approach. In addition, additives which are meant to perform funct ions unrelated to friction and wear may impact the efficacy of frictio n and wear additives. Many of these effects can be explained by the st udy of additive interactions by various spectroscopic, colligative and other physical chemical methods. This paper presents a review of publ ished information on that topic, with a view to stimulate further work as well as to provide insight on issues facing engine oil formulators .