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.

主权项

1. A method for preventing or inhibiting exhaust valve seat recession in a natural gas fueled engine, the method comprising lubricating a natural gas fueled engine in need of exhaust valve seat recession prevention or inhibition with a natural gas engine lubricating oil composition comprising (a) a major amount of an oil of lubricating viscosity; and (b) about 0.5 to about 4.0 wt. %, based on the total weight of the natural gas engine lubricating oil composition, of a low or medium overbased alkali metal-containing detergent having a BN from about 1 to about 200, wherein the low or medium overbased alkali metal-containing detergent is a potassium alkylhydroxybenzoate detergent and wherein the natural gas engine lubricating oil composition is substantially free of each of any alkaline earth metal-containing detergents and lithium-containing detergents, and further wherein the natural gas engine lubricating oil composition has a sulfated ash content of about 0.1 wt. % to about 0.5 wt. % as determined by ASTM D 874.