This invention relates to a lubricating oil composition having a phosphorus content of less than 800 ppm, such as less than or about 500 ppm, and a SASH content of less than 0.9%, such as less than or about 0.5%, comprising a dispersant mixture, the dispersant mixture comprising (1) 0.01-15 mass % based upon the total mass of the dispersant mixture, of an amide, imide, and/or ester functionalized partially or fully saturated polymer comprising C4-5 olefins having: i) an Mw/Mn of less than 2, ii) a Functionality Distribution (Fd) value of 3.5 or less, and iii) an Mn of 10,000 g/mol or more (GPC-PS) of the polymer prior to functionalization; and (2) 50-90 mass % based upon the total mass of the dispersant mixture, of one or more poly(alkenyl) succinimide(s), which is derived from a polyalkenyl-substituted succinic anhydride prepared using a chlorine-assisted alkylation process and a polyamine; and (3) 10-30 mass % based upon the total mass of the dispersant mixture, of one or more poly(alkenyl)succinimide(s), which is derived from a polyalkenyl succinic anhydride prepared using a halogen-free thermal alkylation process and a polyamine.

This invention relates to a lubricating oil composition having a phosphorus content of less than 800 ppm, such as less than or about 500 ppm, and a SASH content of less than 0.9%, such as less than or about 0.5%, comprising a dispersant mixture, the dispersant mixture comprising (1) 0.01-15 mass % based upon the total mass of the dispersant mixture, of an amide, imide, and/or ester functionalized partially or fully saturated polymer comprising C4-5 olefins having: i) an Mw/Mn of less than 2, ii) a Functionality Distribution (Fd) value of 3.5 or less, and iii) an Mn of 10,000 g/mol or more (GPC-PS) of the polymer prior to functionalization; and (2) 50-90 mass % based upon the total mass of the dispersant mixture, of one or more poly(alkenyl) succinimide(s), which is derived from a polyalkenyl-substituted succinic anhydride prepared using a chlorine-assisted alkylation process and a polyamine; and (3) 10-30 mass % based upon the total mass of the dispersant mixture, of one or more poly(alkenyl)succinimide(s), which is derived from a polyalkenyl succinic anhydride prepared using a halogen-free thermal alkylation process and a polyamine.