Patent ID: 7795192

Claim:
A lubricant composition suitable for lubricating a direct fuel injection two-stroke engine, comprising: (a) at least about 40 percent by weight of an oil of lubricating viscosity; (b-1) 2.5 to about 8 percent by weight of at least one condensation product of a fatty hydrocarbyl monocarboxylic acid having about 12 to about 24 carbon atoms with a polyethylene polyamine, and (b-2) 0.5 to about 8 percent by weight, based on the lubricant composition, of at least one Mannich dispersant wherein the Mannich dispersant is the reaction product of a polybutene-substituted phenol, formaldehyde, and ethylenediamine or dimethylamine; (c) 0 to about 45 percent by weight of a combustible solvent having a viscosity of less than 2 mm 2 s −1 (cSt) at 100° C.; and (d) 0.8 to about 2.0 percent by weight of an aromatic amine antioxidant; provided that the total amount of (b-1) plus (b-2) plus any dispersants in the lubricant composition other than (b-1) and (b-2) is at least about 7.5 percent by weight and at most 12 percent by weight, further provided that the total nitrogen content in the lubricant composition is about 0.25 to about 0.75 percent by weight.