The invention provides a lubricant composition containing an oil of lubricating viscosity and a boron-containing compound, wherein the boron containing compound comprises a borate ester comprising at least one alkyl group having a branch at the ? position or higher. The invention further relates to a method of lubricating an internal combustion engine with the lubricant composition.

A lubricating oil composition and method of operating a boosted internal combustion engine with reduced low-speed pre-ignition events and corrosion resistance. The oil composition includes a base oil, one or more overbased calcium sulfonate detergents, one or more overbased calcium phenate detergents, and one or more overbased magnesium-containing detergents. A ratio of ppm of calcium to TBN of the oil composition is less than 170; a ratio of ppm of magnesium to total soap content in wt. % is greater than 700; and there are limited amounts of boron and molybdenum, and all weight percentages and ppm values being based on the total weight of the oil composition. The compositions give low LSPI ratios and pass the Ball Rust test.

Fuels, hydraulic fluids and lubricants made of or comprising a portion of renewable hydrocarbon raw materials, as well as biodegradable fuels, hydraulic fluids and lubricants are known to support microbial growth. Highly toxicorganic biocides have been added to reduce microbial growth. The use of such biocides can now be avoided, by instead using a stable solution of boric acid in a solvent, the boric acid being completely dissolved or at least free from any particles larger than 100 nm in size, and adding this solution to the fuel, hydraulic fluid or lubricant to give a final concentration of boron in the range of 1-100 ppm, preferably 1-50 ppm in the product. While preventing microbial growth, the addition of boron also reduces corrosion, in particular microbiologically induced corrosion (MIC).

The invention is directed to a zinc-free lubricating composition for an internal combustion engine containing a phosphorus anti-wear agent, an ashless antioxidant, and an oxyalkylated phenol compound. The lubricating composition provides wear protection, deposit control, and improved acid control with reduced levels of metal-containing additives.

A lubricating oil composition having a sulfated ash content of from greater than 1.0 wt. % to about 2.0 wt. %, a phosphorus content of from about 0.07 to about 0.12 wt. % and a sulfur content of 0.4 wt. % or less, the lubricating oil composition comprising: (a) an oil of lubricating viscosity in a major amount; (b) an overbased magnesium detergent, in an amount providing the lubricating oil composition with at least 600 ppm of magnesium; (c) a boron-containing compound, in an amount providing the lubricating oil composition with at least 250 ppm of boron; and (d) a molybdenum-containing compound, in an amount providing the lubricating oil composition with at least 50 ppm of molybdenum, wherein the composition has a B/Mo mass ratio in a range of 2 to 10 and a S/Mo mass ratio in a range of 10 to 25.

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.

A gas engine lubricating oil composition comprises an oil of lubricating viscosity including at least 90 mass % saturates and no more than 0.03 mass % to sulfur, a metal hydroxybenzoate detergent additive, a dispersant additive, and an aminic or phenolic antioxidant additive, and has a boron concentration, of zero or less than 90 ppm by mass, where boron, if present, is provided at least in part by a boron-containing dispersant additive. The composition exhibits improved lead corrosion properties and no adverse anti-wear properties.

A method of reducing low-speed pre-ignition (LSPI) in a direct-injected spark-ignited internal combustion engine comprising lubricating the crankcase of the engine with a composition comprising a combination of a molybdenum-containing additive and a boron-containing additive. Preferably, the composition comprises a calcium detergent providing a calcium content of at least 0.08 wt %, based on the weight of the lubricating oil composition.