LUBRICATING OIL COMPOSITIONS

摘要

A method for preventing or inhibiting exhaust valve seat recession in a natural gas fueled engine, the method comprising lubricating the engine with a natural gas engine lubricating oil composition comprising (a) a major amount of an oil of lubricating viscosity, and (b) an alkali metal-containing detergent, wherein the natural gas engine lubricating oil composition is substantially free of each of any alkaline earth metal-containing detergents and lithium-containing detergents is disclosed.