abstract |
A lubricating oil composition having a low sulfated ash content, a low P content, a low S content and a low Cl content and being favorably employable for lubricating a diesel engine operated using a hydrocarbon fuel oil having a low S content, comprises the following components a) to d) dissolved or dispersed in a base oil having a low S content: a) an ashless dispersant such as alkenyl- or alkylsuccinimide or its derivative, b) a calcium alkylsalicylate detergent having a low S content and containing an organic acid calcium salt, which is a mixture of an unsulfurized calcium alkylsalicylate detergent having a C14-C18 alkyl group and an unsulfurized calcium alkylsalicylate detergent having a C20-C28 alkyl group, c) a zinc phosphate anti-wear agent, and d) an oxidation inhibitor. |