Patent ID: 7585820

Claim:
A low sulfur, low sulfated ash and low phosphorus lubricating oil composition for low emission heavy duty diesel engines comprising: (a) a major amount of an oil of lubricating viscosity; (b) a detergent composition comprising (i) a mixture of a metal salt of an alkyl hydroxyaromatic carboxylic acid and a metal salt of an alkyl phenol, and (ii) a metal salt of a Mannich condensation product; and wherein the sulfur content is in the range of 0.0 weight percent to 0.4 weight percent, the sulfated ask content is in the range of 0.2 weight percent to 4.0 weight percent, and the phosphorus content is in the range of 0.005 weight percent to 0.06 weight percent; wherein in (b) the ratio of (i) the mixture of a metal salt of an alkyl hydroxyaromatic carboxylic acid and a metal salt of an alkyl phenol to (ii) the metal salt of a Mannich condensation product is in the range of 80:20 weight percent to 20:80 weight percent based on the total weight of the detergent composition; and wherein in (b)(i), the ratio of the metal salt of an alkyl hydroxyaromatic carboxylic acid to the metal salt of an alkyl phenol is in the range of 80:20 weight percent to 20:80 weight percent based on the total weight of (i).