In accordance with the present invention, there are provided ashless heavy duty diesel lubricating oil compositions which comprise an oil of lubricating viscosity as the major component and as the minor component (A) at least 3 wt.% of at least one ashless dispersant, (B) at least 2 wt.% of at least one sulfurized alkyl phenol, and (C) at least 0.1 wt.% of at least one organo-sulfur compound of the formula
wherein R⁴ and R⁵ are straight or branched chain alkyl, cyclic, alicyclic, aryl, alkylaryl or arylalkyl radicals having from 2 to about 30 carbon atoms, and w and z are numbers from 1 to about 8 wherein the lubricating oil is characterized by a total sulfated ash (SASH) level of less than 0.01 wt.%.
根据本发明,提供了无灰重型柴油润滑油组合物,该组合物包括作为主要成分的润滑 粘度油和作为次要成分的 (A) 至少 3 重量%的至少一种无灰分散剂,(B) 至少 2 重量%的 至少一种
硫化烷基
酚,和 (C) 至少 0.1 重量%的至少一种式中的
有机硫化合物
其中 R⁴ 和 R⁵ 是直链或支链烷基、环烷基、脂环烷基、芳基、烷芳基或芳烷基,具有 2 至 30 个左右碳原子,w 和 z 是 1 至 8 的数字,其中润滑油的总
硫酸盐灰分 (
SASH) 含量小于 0.01 重量百分比。