| abstract |
In diesel engines, soot is produced by combustion and enters into the engine oil, preventing the engine lubricant from fully exercising its lubricity. The present invention provides a lubricating composition comprising a lubricating basestock, an organic molybdenum compound (A) and succinimide (B) having 0.01 or less of an IR spectrum absorbance peak intensity ratio .alpha./.beta., wherein .alpha. represents an absorbance peak intensity at 1,550~10cm-1 and .beta. represents an absorbance peak intensity at 1,700~10cm-1. Preferably, the organic molybdenum compound is the compound represented by the following formula (1) or formula (2): (SEE FORMULA 1) (SEE FORMULA 2) (wherein R1 to R8 each independently represent a hydrocarbon, and X1 to X8 each independently represent a sulfur atom or an oxygen atom), or a reaction product of an amine and a molybdenum compound having at least one pentavalent or hexavalent molybdenum atom. |