Patent ID: 8623799

Claim:
A method for lubricating a cylinder of a marine diesel engine, comprising supplying to said cylinder a lubricant having a total base number (TBN) of at least about 25, which lubricant comprises an oil of lubricating viscosity and a metal-containing detergent component, which detergent component comprises a multiplicity of detergent species; wherein about 55 to about 80 percent of the TBN derived from the metal-containing detergent component is provided by one or more calcium detergents; about 6 to about 15 percent of such TBN is provided by one or more sodium detergents; and about 10 to about 35 percent of such TBN is provided by one or more magnesium detergents; wherein at least about 50 weight percent of the total detergent substrate in the lubricant is sulfonate detergent substrate and less than about 50 weight percent of the total detergent substrate in the lubricant is a monomeric or oligomeric substrate comprising one or more units of alkyl-substituted phenol which in turn comprises at least one alkyl group of about 8 to about 14 carbon atoms; and wherein said marine diesel engine is fueled with a liquid fuel which contains at least about 2 parts per million by weight vanadium.