Lubricating Oil Composition

Abstract

A lubricating oil composition having a phosphorus content of up to 0.12 wt %, a sulfated ash content of up to 1.2 wt % comprising (a) a major amount of an oil of lubricating viscosity; (b) an alkali metal or alkaline earth metal alkyl salicylate lubricating oil detergent providing from 7-15 mmol salicylate soap per kilogram of lubricating oil composition; (c) one or more dispersants providing the lubricating oil composition with from at least 0.12 wt % to 0.20 wt % atomic nitrogen, based on the weight of the lubricating oil composition, and (d) a dispersant-viscosity modifier.

Description

[0001]The present invention relates to lubricating oil compositions. More particularly, the present invention relates to lubricating oil compositions for use in engines comprising emission control systems.BACKGROUND OF THE INVENTION[0002]Environmental concerns have led to continued efforts to reduce the CO, hydrocarbon and nitrogen oxide (NOx) emissions of compression ignited (diesel-fueled) and spark ignited (gasoline-fueled) light duty internal combustion engines. Further, there have been continued efforts to reduce the particulate emissions of compression ignited light duty internal combustion engines. To meet the current and upcoming emission standards for vehicles, original equipment manufacturers (OEMs) rely on the use of exhaust gas after-treatment devices. Such exhaust gas after-treatment devices may include exhaust gas recirculation arrangements and cooled exhaust gas recirculation arrangements, catalytic converters, which can contain one or more oxidation catalysts, NOx st...

AI Technical Summary

Benefits of technology

[0048]Antioxidants reduce the tendency of base stocks to deteriorate in service which deterioration can be evidenced by the products of oxidation such as sludge and varnish-like deposits on the metal surfaces and by viscosity growth. In the present invention they are suitably present in amount of from 0.1 to 5.0 wt. %, Suitable oxidation inhibitors include hindered phenols, alkaline earth metal salts of alkylphenolthioesters having preferably C5 to C12 alkyl side chains, calcium nonylphenol sulfide, ashless oil soluble phenates and sulfurized phenates, phosphosulfurized or sulfurized hydrocarbons, alkyl substituted diphenylamine, alkyl substituted phenyl and napthylamines, phosphorous esters, metal thiocarbamates, ashless thiocarbamates and oil soluble copper compounds as described in U.S. Pat. No. 4,867,890. Most preferred are the dialkyl substituted diphenylamines, wherein the alkyl is C4-C20, such as dinonyl diphenylamine and the hindered phenols, such as isooctyl-3,5-di-tert-butyl-4-hydroxycinnamate and mixtures of same.Zinc Dihydrocarbyldithiophosphates

[0065]Pour point depressants, otherwise known as lube oil flow improvers, lower the minimum temperature at which the fluid will flow or can be poured. Such additives are well known. Typical of those additives which improve the low temperature fluidity of the fluid are C8 to C18 dialkyl fumarate / vinyl acetate copolymers, polyalkylmethacrylates and the like. These may be used in amounts of from 0.01 to 5.0 wt. %, preferably about 0.1 to 3.0 wt. %. They are preferably used when mineral oil base stocks are employed but are not generally required when the base stock is a PAO or synthetic ester,

Problems solved by technology

Oxidation catalysts can become poisoned and rendered less effective by exposure to certain elements / compounds present in engine exhaust gasses, particularly by exposure to phosphorus and phosphorus compounds introduced into the exhaust gas by the degradation of phosphorus-containing lubricating oil additives.

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