Extended drain intervals for crankcase lubricants

Abstract

The various approaches to achieving extended drain intervals in vehicle crankcase lubricants are described, with particular emphasis on commercial diesel engines. The various lubricant contaminants include soot, water, acids and particulate metals. Lubricant life may be prolonged by suitable design of the lubricant and of the engine, but more particularly by reducing the levels of contaminant in the lubricant such that the performance of the lubricant may be maintained. At the same time, wear rates within the engine must be within acceptable levels. The various options for reducing the levels of contaminant include lubricant by‐pass filtration systems, including barrier filters, refiners and centrifugal filters.

Effect of Fuel Adulteration on Engine Crankcase Dilution

“…Crankcase dilution to a limited extent is allowed for an engine long in service. Typically this is less than 5% of the lubricating oil volume for an internal combustion engine before oil replacement is needed [2,3]. On the other hand, some consumption of lubricating oil is common during engine blow-by, but its amount is very small as long as the engine components like piston rings or valve guides do not wear out.…”