| 摘要 |
PROBLEM TO BE SOLVED: To obtain a lubricating oil compsn. which hardly causes the problems due to ash by compounding a lube base oil with a phosphorus-contg. additive and an alkaline earth metal-contg. additive in a specified ratio. SOLUTION: A lube base oil is compounded with at least one phosphorus- contg. additive selected from among zinc dialkyl (or aryl) dithiophosphates and phosphorus-contg. extreme-pressure molybdenum compds. and at least one alkaline earth metal-contg. additive selected from among basic sulfonates, phenates, salicylates, carboxylates, and phosphonates so that the ratio (M/P) of an alkaline earth metal content (M wt.%) to phosphorus content (P wt.%) is 3.5-7. Thus, a lubricating oil compsn. is obtd. which can be suitably used not only in a gas engine wherein the operating load fluctuates greatly but also in an engine which is required to withstand similarly severe load conditions. |
