Patent ID: 7820599

Claim:
A lubricating oil composition comprising: a lubricating oil base oil; an organic molybdenum compound (A) having a Mo content of 100 to 1,000 mass ppm; zinc dialkyl dithiophosphate (B) having a P content of 0.03 to 0.20 mass %; at least one compound (C) selected from calcium sulfonate, calcium phenate, and magnesium sulfonate and having a base number obtained through a perchloric acid method of 230 mgKOH/g or more in a Ca and/or Mg content of 0.15 to 0.30 mass %; and an ashless dispersant comprising boron, or a mixture of an ashless dispersant comprising boron and an ashless dispersant comprising no boron (D) in a B content of 0.03 mass % or more and an N content of 0.05 mass % or more, wherein: a mass ratio (P/Mo) of the P content to the Mo content in the composition is 1.5 or more; a mass ratio (CaMg/Mo) of a total content of the Ca and Mg derived from the component (C) to the Mo content in the composition is 3 or more; and a mass ratio (B/N) between B and N derived from the component (D) in the composition is 0.5 or more.