ABSTRACT
The environmental effects of crankcase- and mixed lubrication are evaluated by following the lubricant in its path through the engine and into the environment. In a crankcase-lubricated engine, the oil is subjected to changes: it absorbs other substances, it also supplies substances to particulate emissions in the exhaust. The contaminated oil then reaches the environment in various ways of which many are uncontrolled. Often, these uncontrolled immissions lead to high concentration of dangerous substances in the environment. In mixed-lubricated engines, there are no significant changes and no cumulative effects in the engine. The oil returns to the environment in a well-defined and finely dispersed way and in extremely low concentrations. In addition, most of the oils used in mixed-lubricated engines are biologically degradable (some are designed to be very well degradable) and no negative environmental effects have been found.
The presentation concludes with a recommendation for engine builders to reconsider the application of mixed-lubrication in all types of engines.
