LUBRICANTS WITH TITANIUM AND/OR TUNGSTEN AND THEIR USE FOR IMPROVING LOW SPEED PRE-IGNITION

摘要

A lubricating oil composition and method of operating a boosted internal combustion engine. The lubricating oil composition includes a major amount of a base oil, one or more overbased calcium-containing detergents having a total base number of greater than (225) mg KOH/gram, to provide greater than (900) ppm by weight to less than (2400) ppm by weight of calcium to the lubricating oil composition, and a low speed pre-ignition reducing amount of one or more titanium-containing compounds to provide from (10) ppm to (3000) ppm titanium and/or one or more tungsten-containing compounds to provide from (125) ppm to (3000) ppm tungsten, all based on the total weight of the lubricating composition. The low speed pre-ignition events in the boosted internal combustion engine may be reduced relative to a number of low speed pre-ignition events in the same engine lubricated with the same lubricating oil without the titanium- and/or tungsten-containing additive.