LUBRICATING OIL COMPOSITION

摘要

A lubricating oil composition comprising: (1) 98.6 to 53% by weight of a base oil having a kinematic viscosity of 3 to 20 centistokes as determined at 100 DEG C.; (2) 0.2 to 5% by weight of a sulfurized oxymetal organophosphorodithioate represented by the formula (I): (I) and/or sulfurized oxymetal dithiocarbamate represented by the formula (II): (II) (3) 0.1 to 7% by weight of at least one zinc dithiophosphate represented by the formula (III): (III) (4) 0.1 to 20% by weight of a calcium alkylbenzenesulfonate and/or a calcium petroleumsulfonate; and (5) 1 to 15% by weight of alkenylsuccinic acid imide and/or boron derivatives thereof. The present lubricating oil composition is superior in reducing the mechanical friction loss of four-cycle engines, particularly small-sized high power four-cycle engines when used as an engine oil.