To provide a lubricating oil particularly useful for an internal combustion engine (particularly, Diesel engine) using a hydrocarbon type fuel of low sulfur content, comprising a lubricating oil composition of low sulfuric acid ash content, low sulfur content and low phosphoric acid content.
A lubricating oil composition comprises mainly a base oil of 85 mass% or more of a saturated ingredient, a viscosity index of 110 or more and a sulfur content of 0.01 mass% or less, which also contains 0.01-0.4 mass% of a cleaning agent containing an alkaline earth metal in terms of an alkaline earth metal content, 0.01-0.3 mass% of a polymeric nitrogen-containing non-ash dispersing agent in terms of nitrogen content, 0.1-5 mass% of a phenol anti-oxidant and/or an amine anti-oxidant, and 0.3-2.0 mass% of an oxy-molybdenum complex of a basic nitrogen compound, wherein the sulfuric acid ash content is 0.1-1.1 mass%, the sulfur content is 0.01-0.3 mass%, the phosphoric acid content is 0.08 mass% or less and a zinc content is 0.07 mass% or less.
COPYRIGHT: (C)2008,JPO&INPIT
Yoshinao Takeuchi
Muramatsu Takahiro
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