Using the most ideal packages of additives in engine oils does not enable one to avoid the development of mechanical admixtures of particulate contaminants from fuel combustion byproducts and airborne contaminants. In this connection, one must modernize the engine design to accommodate the removal of harmful particulate contaminants, which exist in particle sizes of 3-5 micrometers or greater .*It should be noted that even the most active ashless dispersants cannot accommodate higher and higher concentrations of sludge, soot, and airborne contaminants without eventually losing their ability to suspend these contaminants [2, 3]. As more and more contaminants continue to concentrate in the crankcase, it becomes necessary to change the engine oil.It is known that polar-active species (asphalt-resins) can be absorbed on non-organic particulates . These agglomerates may then be physically separated from the oil with the use of a centrifugal cleaner. The portion of the deposits on the centrifugal filter which are the result of fuel combustion has been quantified at 40-50 percent .Therefore, it is possible to employ an effective centrifugal cleaner to maintain oil purity for a reasonable time. Improving engine design and using an effective centrifugal cleaner may improve engine operation by decreasing abrasive wear rates while providing an extension to oil service life.In this work the issue of self-regulation of the engine lubrication system was considered. Particular attention was given to determining the required efficiency of the engine air filter and oil centrifugal cleaner to establish an acceptably low steady-state concentration of particulate contaminants in the crankcase.It has been demonstrated that engines with a series of SPE «Qualitet» air filters and a high-speed centrifugal oil cleaner were able to maintain the particulate contaminant level close to that of fresh (Virgin) engine oil.