LUBRICATING OIL COMPOSITIONS FOR INTERNAL COMBUSTION ENGINES

摘要

A lubricating oil composition having a low P content of 0.01 to 0.1 wt.%, and a sulfated ash of 0.1 to 1 wt.%, which is composed of a) a major amount of mineral base oil having a low S content of at most 0.1 wt.%; b) an ashless alkenyl or alkyl-succinimide dispersant; c) a metal-containing detergent (non-sulfurized alkali metal or alkaline earth metal salt of an alkylsalicylic acid and/or non-sulfurized alkali metal or alkaline earth metal salt of an alkylphenol derivative having a Mannich base structure); d) Zn-DTP; e) an oxidation inhibitor (phenol compound and/or amine compound) and wherein the sulfur content is 0.01 to 0.3 wt %. The lubricating oil composition shows good high temperature detergency notwithstanding its low S, P, and sulfated ash content, and is favorably employable in diesel engines using fuel of an extremely low sulfur content.