A method for improving wear control of a steel surface lubricated with a lubricating oil through the generation of thick tribofilms. The method includes: (i) using as the lubricating oil a formulated oil, the formulated oil having a composition comprising at least one lubricating oil base stock as a major component; and at least one lubricating oil additive, as a minor component; and (ii) forming a tribofilm on the steel surface. In time-step tribofilm formation measurements of the lubricating oil by a mini-traction machine (MTM) at constant slide-to-roll ratio (SRR), the saturation traction coefficient (f.sub.s), which correlates to tribofilm thickness on the steel surface, is greater than about 0.11. In the method of this disclosure, elongation of timing chain due to wear of chain link pins is less than about 0.07%, as determined by Ford Chain Wear (FCW) test conducted in accordance with ILSAC GF-6 specification. The lubricating oils are useful in internal combustion engines.

A method for improving wear control, while maintaining or improving deposit control and cleanliness, in an engine or other mechanical component lubricated with a lubricating oil by using as the lubricating oil a formulated oil. The formulated oil has a composition including a lubricating oil base stock as a major component, and specific combinations of low soap detergents, dispersants, and/or mixtures thereof, as a minor component. The low soap detergents include alkaline earth metal salicylates, alkaline earth metal sulfonates, or mixtures thereof, all having the same or different total base number (TBN). The total amount of soap delivered by the low soap detergent is less than 0.60 weight percent of the lubricating oil. The dispersants include borated and/or non-borated polyisobutylene succinimide (PIMA) having a basic nitrogen content of 1% or greater. The lubricating oils are useful in internal combustion engines.

A method for improving wear control of a steel surface lubricated with a lubricating oil through the generation of fast-forming tribofilms. The method includes: (i) using as the lubricating oil a formulated oil, the formulated oil having a composition comprising at least one lubricating oil base stock as a major component, and at least one detergent, as a minor component; and (ii) forming a tribofilm on the steel surface. The time for the tribofilm to reach 95% of its saturation coverage (t.sub.95,sat) on the steel surface is less than about 50 minutes, as determined by a high frequency reciprocating rig (HFRR) in accordance with a modified version of ASTM D6079. A lubricating oil including an ester base stock, an alkylated naphthalene base stock, or mixtures thereof, as a major component; and at least one detergent including an alkaline earth metal salicylate, an alkaline earth metal sulfonate, or mixtures thereof, as a minor component.

The present disclosure provides a lubricating composition that includes at least one lubricating base oil, an effective amount of at least one overbased detergent; and an effective amount of at least one thermally stable zinc dialkyl dithiophosphate. The disclosure further provides methods of making and using the same.

The invention provides a method of lubricating a transmission which includes a synchronizer with a non-metallic surface, the method comprising supplying thereto a lubricant comprising: (a) an oil of lubricating viscosity; (b) an alkaline earth metal detergent; and (c) a non-aromatic carboxylic acid or a salt thereof having 8 to 24 carbon atoms.

The invention provides a method of lubricating a transmission which includes a synchronizer with a non-metallic surface, the method comprising supplying thereto a lubricant comprising: (a) an oil of lubricating viscosity; (b) an alkaline earth metal detergent; and (c) a non-aromatic carboxylic acid or a salt thereof having 8 to 24 carbon atoms.

A lubricant composition for a direct injected, boosted, spark ignited internal combustion engine that contains at least one non-sulfur-phosphorus containing zinc compound is disclosed. This disclosure also relates to a method for preventing or reducing low speed pre-ignition in an engine lubricated with a formulated oil. The formulated oil has a composition comprising at least one oil soluble or oil dispersible non-sulfur-phosphorus containing zinc compound.

The invention is directed to a method for reducing low speed pre-ignition events in a spark-ignited direct injection internal combustion engine by supplying to the sump a lubricant composition which contains an oil of lubricating viscosity and a metal overbased detergent. The metal overbased detergent may be selected from sulfonate detergents, phenate detergents, and salicylate detergents, especially sulfonate detergents with a metal ratio of at least 5.

The present invention provides a lubricating oil composition for an internal combustion engine, comprising: a lubricating base oil; an ashless friction modifier; and a boron-containing dispersant.

The present invention provides a lubricating oil composition for an internal combustion engine, comprising: a lubricating base oil; an ashless friction modifier; and a boron-containing dispersant.