Lubricating oil composition

摘要

A lubricating oil composition employable in combination with a low sulfur content fuel oil is preferably composed of a base oil having a sulfur content of at most 0.2 wt. %, an ashless dispersant comprising an alkenyl- or alkyl-succinimide or a derivative thereof, a metal-containing detergent containing an organic acid metal salt, a zinc dialkyldithiophosphate, a zinc dialkylaryldithiophosphate, and an oxidation inhibitor selected from the group consisting of a phenol compound, an amine compound, and a molybdenum-containing compound, wherein a ratio of the phosphorus content of the zinc dialkyldithiophosphate to the phosphorus content of the zinc dialkylaryldithiophosphate is in the range of 20:1 to 2:1.

主权项

1. A motor-driven vehicle lubricating oil composition, comprising:
a) a major amount of a base oil having a sulfur content of at most 0.2 wt. %; b) an ashless dispersant comprising an alkenyl- or alkyl-succinimide or a derivative thereof in an amount of 0.01 to 0.3 wt. % in terms of the nitrogen atom content; c) a metal-containing detergent that contains an organic acid metal salt, having a TBN of 10 to 350 mg KOH/g, and a sulfur content of at most 3.5 wt. %, in an amount of 0.1 to 1 wt. % in terms of a sulfated ash content with the proviso that the organic acid metal salt is incorporated into the oil composition in an amount of 0.2 to 7 wt. %; d) a zinc dialkyldithiophosphate in an amount of 0.01 to 0.06 wt. % in terms of a phosphorus content; e) a zinc dialkylaryldithiophosphate in an amount of 0.002 to 0.015 wt. % in terms of the phosphorus content; and f) an oxidation inhibitor selected from the group consisting of a phenol compound, an amine compound, and a molybdenum-containing compound in an amount of 0.01 to 5 wt. %,wherein:
i) the ratio of the phosphorus content of the zinc dialkyldithiophosphate to the phosphorus content of the zinc dialkylaryldithiophosphate in the motor-driven vehicle lubricating oil composition is in the range of 10:1 to 2:1; and ii) the motor-driven vehicle lubricating oil composition has a sulfur content of 0.01 to 0.5 wt. %, a phosphorus content of 0.01 to 0.1 wt. %, and a sulfated ash in the range of 0.1 to 1 wt. %.