A comb polymer can be used for reducing a Noack evaporation loss of a lubricant composition, especially of an engine oil composition. Application of the comb polymer to the lubricant composition can bring about the desired reduction. The comb polymer can include specified amounts of macromonomer and alkyl acrylates. Resulting lubricant compositions can include the comb polymer.

This disclosure provides a method for improving high temperature antifoaming performance of a lubricating oil in an engine or other mechanical component lubricated with the lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition with a lubricating oil base stock as a major component, and at least one silicone antifoaming agent, as a minor component. The silicone antifoaming agent is delivered to the lubricating oil by contacting the lubricating oil with a cured silicone (e.g., room temperature vulcanized (RTV) silicone) at a temperature, and for a period of time, sufficient to deliver silicone to the lubricating oil. The delivered silicone is soluble in the lubricating oil. The lubricating oils are useful as passenger vehicle engine oils (PVEO) and commercial vehicle engine oils (CVEO).

This disclosure relates to a low viscosity lubricating turbine oil having a composition comprising a lubricating oil base stock, as a major component, and one or more lubricating oil additives, as minor components. The lubricating turbine oil has a kinematic viscosity of about 16 cSt to about 22 cSt at 40 C., a density of about 0.8 g/ml to about 0.9 g/ml, and an absolute evaporation loss at 150 C. of less than about 4%. This disclosure also relates to a method for improving energy efficiency in a turbomachine lubricated with the low viscosity lubricating turbine oil. This disclosure further relates to a method for improving energy efficiency while maintaining or improving deposit control and lubricating oil additive solvency in a turbomachine lubricated with the low viscosity lubricating turbine oil. This disclosure yet further relates to a method for improving solubility, compatibility and dispersancy of polar additives in the low viscosity lubricating turbine oil.

A lubricating oil composition comprising a GTL (Gas to-Liquid) base oil synthesized by the Fischer-Tropsch process and a viscosity index improver, wherein the content of the viscosity index improver is 0.1 to 20 mass %, and at least HTHSV 50 C./HTHSV 150 C. is 6.50 or less and KV 50 C./HTHSV 150 C. is 8.00 or less.

A lubricant composition contains a lubricant base oil, (A) a detergent containing magnesium, (B) a compound containing boron, and (C) a zinc dialkyl dithiophosphate. The amount of component (A) is in the range of 200 to 1200 mass ppm [Mg] based on the mass of the lubricant composition, and the amount of component (C) is in the range of 300 to 1000 mass ppm [P] based on the mass of the lubricant composition. Component (C) includes a zinc dialkyl dithiophosphate having a primary alkyl group or a secondary alkyl group; the lubricant composition includes zinc dialkyl dithiophosphate having a secondary alkyl group; the mass ratio of the zinc dialkyl dithiophosphate having a primary alkyl group and the zinc dialkyl dithiophosphate having a secondary alkyl group is from 70:30 to 0:100; and the concentration of [B] is from 100 to 300 mass ppm based on the mass of the lubricant composition.

Provided is a method for improving oxidation resistance and deposit resistance of a lubricating oil for use in lubricating a mechanical component. The method includes the step of providing the lubricating oil to the mechanical component and measuring the improved oxidation and deposit resistance. The lubricating oil includes a lubricating oil base stock at from 0 to 80 wt %, at least one branched isoparaffin having a mole % of epsilon carbon as measured by C.sub.13 NMR of less than or equal to 10% at from 20 to 80 wt %, at least one viscosity modifier at from 5 to 20 wt %, and one or more other lubricating oil additives. The oxidation resistance in the CEC L-109 oxidation resistance test is improved to greater than 310 hours to achieve a 100% viscosity increase and the deposit resistance in the TEOST 33C is improve to total deposits of less than 45 mg as compared to oxidation resistance and deposit resistance achieved using a lubricating oil not containing the at least one branched isoparaffin.

The invention relates to a seal swell agent which is a substituted sulfonyldibenzene compound, and lubricating compositions containing the seal swell agent. The substituents on the benzene rings may be hydrocarbyl groups of 4 to 20 carbon atoms or alkylene groups of 1-2 carbon atoms with further functional groups.

Provided is a lubricating oil composition and method of using such a composition that provides for improved high temperature deposit resistance. The composition includes a lubricating oil base stock at from 20 to 95 wt % of the composition, at least one ashless organic friction modifier at from 0.1 to 20 wt % of the composition, and at least one overbased detergent at from 0.1 to 20 wt % of the composition. The remainder of composition includes one or more other lubricating oil additives. The deposit resistance of the lubricating oil composition as measured by TEOST 33C total deposits is at least 20% lower than the deposit resistance for a comparable lubricating oil composition not including the combination of the at least one ashless organic friction modifier and the at least one overbased detergent.

A comb polymer can be used for reducing a Noack evaporation loss of a lubricant composition, especially of an engine oil composition. Application of the comb polymer to the lubricant composition can bring about the desired reduction. The comb polymer can include specified amounts of macromonomer and alkyl acrylates. Resulting lubricant compositions can include the comb polymer.

Use of a nitrogen-containing ashless dispersant in a lubricating composition for the purpose of reducing wear in the presence of ZDTP and soot wherein the nitrogen-containing ashless dispersant has a Functionality (F) of greater than 1.4.