Lubricants with good TBN retention

摘要

A lubricant composition containing a metal-containing detergent in an amount to provide at least about 2 TBN to the lubricant, and a dispersant comprising an oleophilic portion comprising at least about 40 carbon atoms and an acid-bearing portion, characterized in having a TAN:TBN ratio of at least about 0.8, exhibits good TBN retention.

主权项

1. A lubricant composition comprising:
(a) an oil of lubricating viscosity; (b) at least one metal-containing detergent in an amount to provide at least about 2 to about 10 TBN to the lubricant, said detergent being present in an amount of about 0.5 to about 2 weight percent; said metal-containing detergent comprising an overbased calcium phenate or an overbased calcium sulfonate or mixtures thereof; (c) a dispersant comprising an oleophilic portion comprising at least about 40 carbon atoms and an acid-bearing portion, wherein said dispersant is present in an amount of at least about 0.1 percent by weight and up to 1.5 percent by weight, and wherein said dispersant provides at least about 0.10 TAN to the lubricant composition; wherein said dispersant is a polyolefin-substituted succinic acid; wherein the lubricant composition has a sulfated ash value of about 0.05 percent up to about 1.1 percent; wherein the weight ratio of the metal containing detergent to the polyolefin-substituted succinic acid dispersant is about 4:1 to about 1:1.