| abstract |
A lubricating oil composition prepared by blending a lube base oil with a molybdenum oxysulfide dithiocarbamate with a specified structure, zinc dialkyl dithiophosphate, sulfur compounds, metallic detergents, and boron compounds. The content of molybdenum originating in the dithiocarbamate, that of phosphorus originating in the dithiophosphate, that of the sulfur originating in the sulfur compounds, that of the detergent, and that of the boron originating in the boron compounds are 200-2,000 ppm, 0.02-0.15 wt.%, 0.02-0.30 wt.%, 1-10 wt.%, and 0.005-0.06 wt.%, respectively, based on the whole composition. The composition is excellent in oxidation resistance, does not undergo deterioration caused by nitrogen oxide gases, and can retain the effect of lowering the friction of engines for long. |