A survey of the history of lubricants for diesel engines is presented. Early research programs on ring sticking and scuffing introduced additives to the previously used straight mineral crankcase oils, and also initiated engine testing to measure lubricant performance. The classification systems which evolved from this testing are described in their various stages of development.
The influence of lubricant on engine performance or ring action is examined, and current oil-related problems such as ring belt deposits and ring sticking, oil consumption, and valve train wear are discussed. The question of oil-drain period is also reviewed.
Current research efforts concerning the development of a universal diesel fuel and the evaluation of test results are also described in the paper.