Abstract: Disclosed are compositions of a major amount of alkylated aromatics compounds, in particular alkylated naphthalene and alkylated benzene, optionally combined with API Group II, Group III, Group IV and/or ethylene copolymers, showing improved thermo-oxidation performance when containing an additive combination including an alkylated or non-alkylated diarylamine and a sulfur-containing metal passivator. Particularly, the lubricating compositions include at least 55 wt % of a base oil selected from the group consisting of alkylated naphthalene, alkylated benzene and combinations thereof, and from 0 wt % to 45 wt % of another base oil component. The ratio of amine component to sulfur component in the additive combination is from 1:1 to 20:1. The compositions contain an amount of base oil other than alkylated naphthalene, alkylated benzene and API Group II, Group III, Group IV and/or ethylene copolymers of less than 10 wt % based on the total weight of the components comprising the lubricating composition.

Abstract: Disclosed are compositions of a major amount of alkylated aromatics compounds, in particular alkylated naphthalene and alkylated benzene, optionally combined with API Group II, Group III, Group IV and/or ethylene copolymers, showing improved thermo-oxidation performance when containing an additive combination including an alkylated or non-alkylated diarylamine and a sulfur-containing metal passivator. Particularly, the lubricating compositions include at least 55 wt % of a base oil selected from the group consisting of alkylated naphthalene, alkylated benzene and combinations thereof, and from 0 wt % to 45 wt % of another base oil component. The ratio of amine component to sulfur component in the additive combination is from 1:1 to 20:1. The compositions contain an amount of base oil other than alkylated naphthalene, alkylated benzene and API Group II, Group III, Group IV and/or ethylene copolymers of less than 10 wt % based on the total weight of the components comprising the lubricating composition.

Abstract: An apparatus for evaluating deposit formation characteristics of lubricant samples. The apparatus includes a reactor chamber having a closed first end and a second end, said closed first end of said reactor chamber forming a lubricant sump and said second end open to the atmosphere, an electric heater for heating a test coupon positioned thereon, said electric heater positioned within said reactor chamber, above said lubricant sump, an air supply tube, said air supply tube having a first end in fluid communication with a source of air and a second end, said second end positioned adjacent the test coupon, said air supply tube having a sample orifice located between said first end and said second end of said air supply tube and a lubricant supply tube, said lubricant supply tube having a first end positioned within said lubricant sump and in fluid communication with a source of lubricant and a second end, said second end positioned within said sample orifice of said air supply tube.