| 摘要 |
<p>A lubricating oil composition comprising: a base oil; at least one boron-free ashless dispersant selected from hydrocarbyl substituted succinimides, hydrocarbyl substituted succinic acids and hydrocarbyl substituted succinamides; at least one sulfur source selected from sulfurized polyisobutylenes and polysulfides; and at least one phosphorus source selected from oil-soluble amine salts of formula: <CHEM> in which R<6> is a hydrocarbyl group having 2 to 12 carbon atoms, each X is independently S or O, Y is selected from a hydrocarbyl group having 2 to 12 carbon atoms, <+>NH3R<7> or H, R<7> is a hydrocarbyl group having 4 to 30 carbon atoms, Z is selected from a hydrocarbyl group having 2 to 12 carbon atoms, <+>NH3R<8> or H and R<8> is a hydrocarbyl group having 4 to 30 carbon atoms, provided that Y is <+>NH3R<7> and/or Z is <+>NHR<8>; wherein the total amount of the ashless dispersant, sulfur source and phosphorus source is 1 to 10 percent by weight of the lubricating oil composition and wherein the proportions of the dispersant, the sulfur source and the phosphorus source are selected such that the lubricating oil composition has an L-60-1 carbon/varnish rating of at least about 7.5 and an L-60-1 sludge rating of at least about 9.4.</p> |
