| abstract |
Disclosed herein is a method of lubricating an internal combustion engine by lubricating the engine with a lubricant composition selected from the group of lubricants consisting of: (i) a lubricant composition comprising (a) a mixture of about 3 wt% to about 30 wt% pentaerythritol esters in a base stock wherein said lubricating composition contains more than about 18 wt% saturates; (b) 0 to 2 wt% of at least one triol ester; (c) 0.33 to about 3.3 wt% of a borated hydrocarbyl succinimide (active ingredient) and wherein the percentages are based upon the total lubricating composition; (ii) a lubricant composition comprising (a) about at least 20 wt% of one or more base stocks selected from the group consisting of Group II base stocks, Group III base stocks, and wax isomerates; (b) about at least 4 wt% of a hydrocarbyl aromatic; (c) 0.33 to 3.3 wt% of a borated hydrocarbyl succinimide (active ingredient), and wherein the percentages are based upon the total lubricating composition; and, (iii) a lubricant composition comprising (a) one or more base stocks selected from the group consisting of Group II base stock, Group III base stocks and wax isomerates; (b) an amorphous olefin copolymer; and (c) 0.33 to 3.3wt% of a borated hydrocarbyl succinimide. These compositions can provide substantial reductions in the coefficient of friction and fuel economy improving benefits when admixed to lubricating oils without deleterious effects such as instability, undesirable high viscosities and deposits. Pentaerythritol esters and optionally triol esters are added to lubricating oil compositions to provide reduced friction and improved fuel economy. Preferably the borated hydrocarbyl succinimide used in a lubricating oil composition comprising paraffinic base oil stocks are a borated polyisobutenyl succinimide ashless dispersant. |