| abstract |
An engine oil composition which is excellent in reducing deposits generated in an engine combustion chamber and has a long life. SOLUTION: A calcium detergent is contained in an amount of 0.2 to 0.8% by mass in terms of calcium, and the calcium detergent is a calcium salicylate having a perchloric acid method base number of 50 mgKOH / g or more and the base number of 150 mgKOH / g. A dialkyl having a primary alkyl group having 8 to 12 carbon atoms represented by the following formula (1), wherein both of the above calcium phenates contain a calcium salicylate content of 50 to 90% in terms of base number. An engine oil composition containing zinc dithiophosphate in an amount of 0.02 to 0.2% by mass in terms of phosphorus and having an initial rate of sulfuric acid neutralization of the engine oil composition of 1.0 kPa or less in terms of gas generation pressure. In the following formula, R 1 , R 2 , R 3 and R 4 are primary alkyl groups having 4 to 12 carbon atoms, one or more of which are primary alkyl groups having 8 to 12 carbon atoms, Each may be the same or different. [Selection figure] None |