Lubricating Oil Composition

Abstract

SAE 0W and SAE 5W multigrade crankcase lubricating oil compositions for heavy duty diesel (HDD) engines meeting the performance requirements of at least one of the API CJ-4; API-CI-4, and / or ACEA A7 specifications, having a sulfated ash content of no greater than 1.0 mass %, a sulfur content of no greater than 0.4 mass %, and a phosphorus content of no greater than 0.12 mass %, formulated with a major amount of oil of lubricating viscosity including less than about 30 mass %, based on the total mass of oil of lubricating viscosity, of Group IV and / or Group V base stock, at least 0.3 mass %, of a non-hydrogenated olefin polymer; and greater than about 40 ppm, of boron.

Description

FIELD OF THE INVENTION[0001]The present invention relates to SAE 0W and SAE 5W multigrade crankcase lubricants for heavy duty diesel (HDD) engines that have less than 50 mass % of Group IV and Group V base stock, containing phosphoras-based antiwear agents in an amount introducing no greater than 1200 ppm of phosphorus into the lubricant, which lubricants meet the wear performance requirements of API CJ-4, API CI-4 and / or ACEA E7 specifications.BACKGROUND OF THE INVENTION[0002]Crankcase lubricants comprise base stock and additives that delay degradation of the base stock and improve its performance. Such additives typically include dispersant, overbased and neutral salts of organic acids, corrosion inhibitors, antiwear agents, antioxidants, friction modifiers, antifoamants, and demulsifiers. These additives may be combined in a package, sometimes referred to as a detergent inhibitor (or DI) package. The additives in such a package may include functionalized polymers, but these have ...

AI Technical Summary

Benefits of technology

[0021]In accordance with a seventh aspect of the invention, there is provided a method for improving the fuel economy and wear performance of a heavy duty diesel (HDD) engine, which method comprises the steps of lubricating the engine with a lubricating oil composition as described in any of the first through fifth aspects, and operating the lubricated engine.

[0022]In accordance with a eighth aspect of the invention, there is provided the use of a lubricating oil composition as described in any of the first through fifth aspects to improve the fuel economy and wear performance of a heavy duty diesel (HDD) engine.

Problems solved by technology

However the lubricant should not be too viscous because excessive viscosity may cause unnecessary viscous drag and work to pump the lubricant which in turn can increase fuel consumption.

Merely blending base stocks of different viscosity characteristics may not enable the formulator to meet the low and high temperature viscosity requirements of some multigrade oils.

However, the use of an increased amount of viscosity modifier results in increased low temperature lubricant viscosity.

Alternative means of providing wear protection are particularly critical in low viscosity lubricants formulated with lower viscosity base stocks which, as noted above, are less capable of contributing to antiwear performance at high temperature.

However, Group IV and Group V base stocks are expensive relative to Group I, Group II and Group III mineral oil base stocks.

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