| abstract |
A fully formulated lubricating oil composition has a dispersant mixture derived from a reaction product of polyalkylene compound, a carboxylic acylating agent, and a polyamine. The polyalkylene compound of at least one dispersant in the dispersant mixture has a number average molecular weight of at least about 1200 and at least one dispersant in the dispersant mixture contains boron such that a weight ratio of boron to nitrogen (B/N) in the dispersant mixture ranges from above about 0.25 to about 1.0. The dispersant can be of the Mannich type, the succinimide type, the amine type or the Koch type, and may be boronated. A metal-containing detergent (e.g. an overbased calcium sulfonate) may also be present. |