Low viscosity lubricating oil

Abstract

A lubricating oil composition for an internal combustion engine having a roller follower type valve train is disclosed. The composition comprises: a large amount of an oil of lubricating viscosity; one or more magnesium detergents in an amount to provide from 100 to 1000 ppm magnesium to the lubricating oil composition; 0.1 wt% to 0.5 wt% of an organic friction modifier; and d) optionally a viscosity modifier present in no more than 0.5% by weight. The composition is substantially free of molybdenum friction modifiers and has a total boron content ranging from 20 to 200 ppm.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 321,791, filed on March 21, 2022, which is hereby incorporated by reference herein. Technical Field

[0003] The present disclosure relates to low viscosity lubricating oil compositions that improve fuel economy. Background Art

[0004] The goal of modern automobile and engine design is to improve fuel economy without sacrificing performance or durability. Therefore, the use of roller follower type valve trains has become common in modern automobiles because this new design greatly reduces friction losses in the valve train compared to older designs.

[0005] While these performance gains are encouraging, new lubricant formulations are being designed to further improve fuel efficiency and meet the demands of new engine designs.

[0006] One potential area for improvement involves the use of friction modifiers. It is well known that conventional friction modifiers, such as molybdenum dithiocarbamate (MoDTC), reduce the surface friction of lubricating oils and allow for better fuel economy. However, these friction modifiers may cause undesirable side effects. For example, MoDTC may increase deposit formation and seal degradation. MoDTC may also defeat anti-wear components in terms of surface sites (which may be limited), thereby not allowing the formation of anti-wear films, which may lead to increased wear. Summary of the invention

[0007] In one aspect, a lubricating oil composition for an internal combustion engine having a roller follower type valve train is provided, the lubricating oil composition comprising: a) a major amount of oil of lubricating viscosity; b) one or more magnesium detergents in an amount to provide 100 to 1000 ppm of magnesium to the lubricating oil composition; c) 0.1 wt % to 0.5 wt % of an organic friction modifier; and d) optionally a viscosity modifier present in an amount not exceeding 0.5 wt %, wherein the lubricating oil composition is substantially free of molybdenum friction modifiers and has a total boron content in the range of 20 to 200 ppm.

[0008] In another aspect, a method for improving the fuel efficiency of an internal combustion engine is provided, wherein the method comprises: lubricating the internal combustion engine with a lubricating oil composition, the lubricating oil composition comprising: a) a major amount of oil of lubricating viscosity; b) one or more magnesium detergents in an amount to provide 100 to 1000 ppm of magnesium to the lubricating oil composition; c) 0.1 wt % to 0.5 wt % of an organic friction modifier; and d) an optional viscosity modifier present in an amount not exceeding 0.5 wt %, wherein the lubricating oil composition is substantially free of molybdenum friction modifiers and has a total boron content in the range of 20 to 200 ppm. DETAILED DESCRIPTION

[0009] In this specification, the following words and expressions if and when used have the following ascribed meanings.

[0010] The term "oil soluble" means that for a given additive, the amount required to provide the desired activity or performance level can be incorporated by dissolving, dispersing or suspending in an oil of lubricating viscosity. Typically, this means that at least 0.001 wt. % of the additive can be incorporated into the lubricating oil composition.

[0011] "Major amounts" means greater than 50% by weight of the composition, based on the total lubricating oil composition.

[0012] "Minor amount" means less than 50% by weight of the composition, based on the total lubricating oil composition.

[0013] An "engine" or "combustion engine" is a heat engine in which the combustion of fuel occurs in a combustion chamber. An "internal combustion engine" is a heat engine in which the combustion of fuel occurs in a confined space (the "combustion chamber").

[0014] It has now been discovered that significant improvements in fuel economy can be achieved in internal combustion engines, including engines having roller follower type valve trains, via low viscosity lubricating oil compositions without the use of molybdenum friction modifiers.

[0015] Lubricating oil compositions generally comprise 1) a major amount of oil of lubricating viscosity, 2) a magnesium detergent, 3) an organic friction modifier, and 4) an optional viscosity modifier. Lubricating oil compositions are characterized by containing limited or substantially no (less than about 50 ppm) molybdenum friction modifiers.

[0016] The lubricating oil composition is characterized by relatively low viscosity, and has a kinematic viscosity at 100° C. in the range of 4.0 cSt and 4.5 cSt, such as 4.1 cSt to 4.4 cSt, and 4.2 cSt to 4.3 cSt. Such low viscosity is achieved in the absence of a viscosity modifier or with a very small amount of a viscosity modifier, as compared to some or many conventional lubricants.

[0017] The total boron content of the lubricating oil composition ranges from 20 to 200 ppm.

[0018] Magnesium detergent

[0019] The lubricating oil composition comprises one or more magnesium detergents to provide 100 to 1000 ppm of magnesium to the lubricating oil composition, such as 100 to 900 ppm, 100 to 800 ppm, 100 to 700 ppm, 100 to 600 ppm, 100 to 500 ppm, 200 to 1000 ppm, 200 to 900 ppm, 200 to 800 ppm, 200 to 700 ppm, 200 to 600 ppm, 200 to 500 ppm, 300 to 1000 ppm, 300 to 900 ppm, 300 to 800 ppm, 300 to 700 ppm, 300 to 600 ppm, 300 to 500 ppm, 400 to 1000 ppm, 400 to 900 ppm, 400 to 800 ppm, 400 to 700 ppm ppm, 400 to 600 ppm, 400 to 500 ppm.

[0020] Any detergent that can be coordinated with magnesium is generally compatible with the present invention. Particularly useful detergents include oil-soluble sulfonates (e.g., alkylaryl sulfonates), hydroxyaromatic carboxylates (e.g., salicylates, alkylhydroxybenzoates, etc.), and phenates. The detergents of the present invention can have a wide range of TBN values. For example, the detergent can be a neutral detergent, a slightly overbased detergent, a moderately overbased detergent, a highly overbased detergent, etc.

[0021] The synthesis of various magnesium detergents is generally known and disclosed, for example, in U.S. Publication No. 20110136711, which is incorporated herein by reference. For example, magnesium sulfonate can be prepared by reacting alkyltoluene sulfonic acid with a magnesium source (e.g., magnesium oxide, magnesium hydroxide, magnesium alkoxide, etc.) in the presence of an organic solvent and a low molecular weight alcohol. The reaction product is contacted with at least one promoter and water, and then contacted with an overbased acid and distilled.

[0022] Sulfonates can be prepared from sulfonic acids, which are generally obtained by sulfonation of alkyl-substituted aromatic compounds (such as those obtained from petroleum fractionation) or by alkylation of aromatic compounds. Examples include those obtained by alkylating benzene, toluene, xylene, naphthalene, biphenyl or their halogen derivatives. Alkylation can be carried out with an alkylating agent having from about 3 to more than 70 carbon atoms in the presence of a catalyst. Each alkyl-substituted aromatic moiety of the alkylaryl sulfonate generally contains from about 9 to about 80 or more carbon atoms, preferably from about 16 to about 60 carbon atoms, preferably from about 16 to about 30 carbon atoms, and more preferably from 20 to 24 carbon atoms.

[0023] According to one embodiment, the detergent may include one or more magnesium salts of hydroxyaromatic carboxylates. Suitable hydroxyaromatic compounds include mononuclear monohydroxy and polyhydroxy aromatic hydrocarbons having 1 to 4 and preferably 1 to 3 hydroxyl groups. Suitable hydroxyaromatic compounds include phenol, catechol, resorcinol, hydroquinone, pyrogallol, cresol, etc.

[0024] According to one embodiment, the detergent may include one or more magnesium salts of phenates. Suitable phenates may be prepared by reacting magnesium hydroxide or magnesium oxide with an alkylphenol or a sulphurized alkylphenol. Useful alkyls include straight or branched C1 to C30 (e.g., C4 to C20) alkyls or mixtures thereof. Examples of suitable phenols include isobutylphenol, 2-ethylhexylphenol, nonylphenol, dodecylphenol, etc. It should be noted that the starting alkylphenol may contain more than one alkyl substituent that is independently straight or branched. When non-sulphurized alkylphenol is used, sulphurized products may be obtained by methods well known in the art. These methods include heating a mixture of an alkylphenol and a sulphurizing agent (e.g., elemental sulphur, sulphur halides such as sulphur dichloride, etc.), and then reacting the sulphurized phenol with a magnesium base.

[0025] Organic friction modifiers

[0026] The lubricating oil composition is substantially free of molybdenum friction modifiers. Examples of molybdenum friction modifiers include, for example, molybdenum dithiocarbamates, molybdenum dithiophosphates, and sulfur-containing trinuclear molybdenum compounds, such as those described in U.S. Pat. No. 6,232,276, which is incorporated herein by reference.

[0027] In contrast, the lubricating oil composition of the present invention comprises an organic friction modifier. In some embodiments, the organic friction modifier is borated (borated organic friction modifier) ​​and contributes to the total boron content of the lubricating oil composition. In other embodiments, the organic friction modifier is not borated. In the case of using a non-borated organic friction modifier, other borated components (e.g., a borated dispersant) are required to meet the boron content requirements of the lubricating oil composition.

[0028] As an illustrative, non-limiting example, a borated organic friction modifier (e.g., borated glycerol monooleate) compatible with the present invention can be represented by, for example, Structure 1, wherein each X is independently a hydrocarbon group having 10 to 20 carbon atoms, such as 10 to 18 carbon atoms, 10 to 16 carbon atoms, 12 to 20 carbon atoms, 12 to 18 carbon atoms, 12 to 16 carbon atoms, 14 to 20 carbon atoms, 14 to 18 carbon atoms, and 14 to 16 carbon atoms. X can be saturated or unsaturated. In some embodiments, X is branched. In other embodiments, X is linear.

[0029]

[0030] Structure 1

[0031] The borated organic friction modifier (e.g., borated diolein) can be a diester, such as that represented by the following Structure 2:

[0032]

[0033] Structure 2

[0034] Borated organic friction modifiers, such as those represented by Structures 1 and 2, are generally known and commercially available or prepared using known methods. Conventional synthesis involves the reaction of glycerol, boric acid, and a fatty acid (e.g., oleic acid). A more detailed description of borated friction modifiers can be found in U.S. Pat. Nos. 4,530,771 and 5,629,272, which are incorporated herein by reference.

[0035] Non-borated organic friction modifiers (e.g., glycerol monooleate) can be represented by, for example, structures 3 and 4, wherein each Y is independently a hydrocarbon group having 10 to 20 carbon atoms, such as 10 to 18 carbon atoms, 10 to 16 carbon atoms, 12 to 20 carbon atoms, 12 to 18 carbon atoms, 12 to 16 carbon atoms, 14 to 20 carbon atoms, 14 to 18 carbon atoms, and 14 to 16 carbon atoms. Y can be saturated or unsaturated. In some embodiments, Y is branched. In other embodiments, Y is linear.

[0036]

[0037] Structure 3

[0038]

[0039] Structure 4

[0040] The organic friction modifier is incorporated into the lubricating oil composition in an amount ranging from 0.1 to 0.5 wt %, such as 0.15 to 0.45 wt %, 0.18 to 0.42 wt %, 0.20 to 0.40 wt % and 0.25 to 0.35 wt %, based on the total lubricating oil composition.

[0041] When present, the borated organic friction modifier contributes to the boron content of the lubricating oil composition such that the total boron content of the lubricating oil composition is from 20 to 200 ppm, such as from 20 to 180 ppm, 20 to 160 ppm, 20 to 140 ppm, 20 to 120 ppm, 20 to 100 ppm, 40 to 200 ppm, 40 to 180 ppm, 40 to 160 ppm, 40 to 140 ppm, 40 to 120 ppm, 40 to 100 ppm, 60 to 200 ppm, 60 to 180 ppm, 60 to 160 ppm, 60 to 140 ppm, 60 to 120 ppm, 60 to 100 ppm, 80 to 200 ppm, 80 to 180 ppm, 80 to 160 ppm, 80 to 140 ppm, 80 to 120 ppm, and 80 to 100 ppm.

[0042] Dispersants

[0043] The lubricating oil composition may contain non-borated and / or borated dispersants. Dispersants include, for example, polyalkenyl succinimide dispersants, which may be post-treated with a boron-containing agent to form a borated component that contributes to the total boron content of the lubricating oil composition.

[0044] In one embodiment, the polyalkenyl bissuccinimide can be prepared by reacting a polyalkenyl substituted succinic anhydride of the structure

[0045]

[0046] (wherein R is a polyalkenyl substituent derived from a polyolefin group having a number average molecular weight of about 500 to about 3000) and a polyamine. In one embodiment, R is a polyalkenyl substituent derived from a polyolefin group having a number average molecular weight of about 1000 to about 2500. In one embodiment, R is a polyisobutylene substituent derived from a polyisobutylene having a number average molecular weight of about 500 to about 3000. In another embodiment, R is a polyisobutylene substituent derived from a polyisobutylene having a number average molecular weight of about 1000 to about 2500.

[0047] Suitable polyamines for preparing the bis-succinimide dispersant include polyalkylene polyamines. Such polyalkylene polyamines typically contain from about 2 to about 12 nitrogen atoms and from about 2 to 24 carbon atoms. Particularly suitable polyalkylene polyamines are those having the formula: H2N—(R'NH)x—H, wherein R' is a linear or branched alkylene group having 2 or 3 carbon atoms, and x is 1 to 9. Representative examples of suitable polyalkylene polyamines include ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, and heavy polyamines (e.g., Ethyleneamine E-100, available from Huntsman Company).

[0048] In general, the polyalkenyl-substituted succinic anhydride is reacted with the polyamine at a temperature of about 130° C. to about 220° C. (e.g., 145° C. to 175° C.). The reaction can be carried out under an inert atmosphere, such as nitrogen or argon. In general, a suitable molar charge of the polyamine to the polyalkenyl-substituted succinic anhydride is about 0.35:1 to about 0.6:1 (e.g., 0.4:1 to 0.5:1). As used herein, "molar charge of polyamine to polyalkenyl-substituted succinic anhydride" means the ratio of the number of moles of polyamine to the number of succinic acid groups in the succinic anhydride reactant.

[0049] One class of suitable polyalkenyl succinimides can be represented by the following structure:

[0050]

[0051] wherein R and R' are as described herein above and y is 1 to 11.

[0052] Post-treatment of polyalkenyl succinimide

[0053] The succinimide dispersant can be post-treated by a reactive boron compound. Suitable boron compounds that can be used as a boron source include, for example, boric acid, borates, boric esters, etc. Representative examples of boric acid include orthoboric acid, metaboric acid, paraboric acid, etc. Representative examples of borates include ammonium borate, such as ammonium metaborate, ammonium tetraborate, ammonium pentaborate, ammonium octaborate, etc. Representative examples of boric esters include monomethyl borate, dimethyl borate, trimethyl borate, monoethyl borate, diethyl borate, triethyl borate, monopropyl borate, dipropyl borate, tripropyl borate, monobutyl borate, dibutyl borate, tributyl borate, etc.

[0054] Viscosity Improver

[0055] The lubricating oil composition may optionally contain a viscosity improver. Well-known viscosity improvers that are compatible with the present invention include polymethacrylates (PMAs), olefin copolymers (OCPs), and hydrogenated styrene-diene type (HSD) polymer viscosity improvers.

[0056] The viscosity modifier may be present at about 0.5 wt % or less, such as 0.4 wt % or less, 0.3 wt % or less, and 0.2 wt % or less.

[0057] In some embodiments, the polymethacrylate may be a non-dispersant comb polymethacrylate, which is described in US 2017 / 0298287A1 and JP2019014802, the disclosures of which are incorporated herein by reference. The non-dispersant comb PMA may be obtained from Viscoplex available from Evonik ® Viscosity index improvers 3-201 and / or 3-162 are provided.

[0058] According to one embodiment, the non-dispersant comb PMA is made of a so-called Viscoplex ® The present invention provides a compound of 3-201, which includes a comb-shaped PMA as a main resin component. The weight average molecular weight (Mw) of the non-dispersant comb-shaped PMA is 420,000 g / mol, the number average molecular weight (Mn) is 70,946 g / mol and Mw / Mn is 5.92. The compound has at least one constituent unit derived from a macromolecular monomer with an Mn of 500 or more. Based on the total weight of the compound, the non-dispersant comb-shaped PMA is present in an amount of 19 weight %.

[0059] According to another embodiment, the non-dispersant comb PMA is made of a so-called Viscoplex ® The compound of 3-162 is provided, which also includes a comb-like PMA as a main resin component. The non-dispersant comb-like PMA has a weight average molecular weight (Mw) of 399,292 g / mol, a number average molecular weight (Mn) of 205,952 g / mol, a Mw / Mn of 1.94 and a shear stability index (SSI) of 0.6.

[0060] According to another embodiment, the non-dispersant comb PMA is provided by a combination of compounds, such as Viscoplex ® 3-201 and Viscoplex ® 3-162 combination.

[0061] Other suitable viscosity modifiers include linear polymethacrylates, which are described in US Pat. Nos. 3,607,749 and 8,778,857, which are incorporated herein by reference.

[0062] Olefin copolymers are also well known and are described, for example, in US Pat. Nos. 7,402,235 and 5,391,617, which are incorporated herein by reference.

[0063] Styrene-diene type viscosity modifiers can be prepared by copolymerizing styrene and butadiene and hydrogenating the unsaturated copolymer and are described in US Pat. Nos. 4,116,917, 3,772,196, and 4,788,316, which are incorporated herein by reference.

[0064] Oil of lubricating viscosity

[0065] Oil of lubricating viscosity (sometimes referred to as "base stock" or "base oil") is the main liquid component of the lubricant, into which additives and possibly other oils are blended to produce the final lubricant (or lubricant composition). Base oils are useful in preparing concentrates and in preparing lubricating oil compositions therefrom, and may be selected from natural and synthetic lubricating oils and combinations thereof.

[0066] Natural oils include animal and vegetable oils, liquid petroleum oils and hydrorefined, solvent treated mineral lubricating oils of the paraffinic, naphthenic and mixed paraffinic-naphthenic types. Oils of lubricating viscosity derived from coal or shale can also be used as base oils.

[0067] Synthetic lubricating oils include hydrocarbon oils such as polymerized and interpolymerized olefins (e.g., polybutene, polypropylene, propylene-isobutylene copolymers, chlorinated polybutene, poly(1-hexene), poly(1-octene), poly(1-decene)); alkylbenzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di(2-ethylhexyl)benzene); polyphenols (e.g., biphenyl, terphenyl, alkylated polyphenols); and alkylated diphenyl ethers and alkylated diphenyl sulfides and derivatives, analogs and homologs thereof. Polymerized olefins may also be derived from biogenic sources, such as terpene olefins, such as myrcene, ocimene and farnesene, which may also be copolymerized with other olefins and, if desired, may be further isomerized.

[0068] Another class of suitable synthetic lubricating oils includes esters of dicarboxylic acids (e.g., malonic acid, alkylmalonic acid, alkenylmalonic acid, succinic acid, alkylsuccinic acid and alkenylsuccinic acid, maleic acid, fumaric acid, azelaic acid, suberic acid, sebacic acid, adipic acid, linoleic acid dimer, phthalic acid) with various alcohols (e.g., butanol, hexanol, dodecanol, 2-ethylhexanol, ethylene glycol, diethylene glycol monoether, propylene glycol). Specific examples of these esters include dibutyl adipate, bis(2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate, 2-ethylhexyl diester of linoleic acid dimer, and complex esters formed by reacting one mole of sebacic acid with two moles of tetraethylene glycol and two moles of 2-ethylhexanoic acid.

[0069] Esters that can be used as synthetic oils also include C5 to C 12 Esters made from monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol and tripentaerythritol.

[0070] Additionally, esters from biogenic sources may also be used as synthetic oils.

[0071] Base oils may be derived from Fischer-Tropsch hydrocarbons. Fischer-Tropsch hydrocarbons are produced from synthesis gas containing H2 and CO using a Fischer-Tropsch catalyst. Such hydrocarbons generally require further processing in order to be useful as base oils. For example, the hydrocarbons may be hydroisomerized; hydrocracking and hydroisomerization; dewaxing; or hydroisomerization and dewaxing using processes known to those skilled in the art.

[0072] Unrefined oils, refined oils and re-refined oils can be used in the lubricating oil composition of the present invention. Unrefined oils are oils obtained directly from natural or synthetic sources without further purification treatment. For example, shale oils obtained directly from retorting operations, petroleum oils obtained directly from distillation, or ester oils obtained directly from esterification processes and used without further treatment will be unrefined oils. Refined oils are similar to unrefined oils, except that they are further treated in one or more purification steps to improve one or more properties. Many such purification techniques such as distillation, solvent extraction, acid or base extraction, filtration and percolation are known to those skilled in the art.

[0073] Re-refined oils are obtained by applying processes similar to those used to obtain refined oils to refined oils that are already in use. Such re-refined oils are also known as reclaimed oils or reprocessed oils and are often additionally processed by technologies that license spent additives and oil breakdown products.

[0074] Therefore, the base oil that can be used to prepare the lubricating oil composition of the present invention can be selected from any base oil in Group IV as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines (API Publication 1509). Such base oils are summarized in the following Table 1:

[0075] Table 1

[0076]

[0077] (a) Groups I-III are mineral oil based stocks.

[0078] (b) Determined according to ASTM D2007.

[0079] (c) Determined according to ASTM D2622, ASTM D3120, ASTM D4294, or ASTM D4927.

[0080] (d) Determined according to ASTM D2270.

[0081] Suitable base oils for use herein are any of the groups corresponding to API Group II, III, IV and V oils and combinations thereof, preferably Group III to V oils due to their excellent volatility, stability, viscometry and cleanliness characteristics.

[0082] The oil of lubricating viscosity (also referred to as base oil) used in the lubricating oil composition of the present disclosure is generally present in a large amount, for example, based on the total weight of the composition, an amount greater than 50% by weight, such as greater than about 70% by weight, greater than about 80% by weight, greater than 90% by weight. The expression "base oil" as used herein should be understood to mean a base stock or base stock blend, which is produced by a single manufacturer to the same specifications (regardless of the feed source or manufacturer location), meets the same manufacturer specifications, and is identified by a unique formulation, product identification number or both. The base oil used herein can be any currently known or later discovered oil of lubricating viscosity for formulating a lubricating oil composition for any and all such applications, such as engine oil, marine cylinder oil, functional fluids such as hydraulic oil, gear oil, transmission fluid, etc. In addition, the base oil used herein may optionally contain additional viscosity improvers or viscosity index improvers, such as comb-like polymethacrylate polymers / polymethacrylate alkyl ester polymers, olefin copolymers, ethylene-propylene copolymers or styrene-butadiene copolymers, etc. and mixtures thereof.

[0083] As will be readily appreciated by those skilled in the art, the viscosity of the base oil depends on the application. Generally speaking, a base oil used alone as an engine oil will have a kinematic viscosity range of about 4 cSt to about 8 cSt at 100°C and will be selected or blended depending on the desired end use and additives in the finished oil to give a desired grade of engine oil, such as lubricating oil compositions having SAE viscosity grades of 0W, 0W-8, 0W-12, 0W-16, 0W-20, 0W-30, 0W-40, 0W-50, 0W-60, 5W, 5W-16, 5W-20, 5W-30, 5W-40, 5W-50, 5W-60, 10W, 10W-20, 10W-30, 10W-40, 10W-50, 15W, 15W-20, 15W-30, 15W-40, 30, 40, etc. The lubricating oil composition also has a viscosity index of about 200 or less.

[0084] Lubricant Additives

[0085] The lubricating oil composition of the present invention may also contain conventional lubricant additives for imparting auxiliary functions to obtain a finished lubricating oil composition in which these additives are dispersed or dissolved. For example, the lubricating oil composition may be blended with antioxidants, ashless dispersants, antiwear agents, detergents (such as metal detergents), rust inhibitors, demisters, demulsifiers, friction modifiers, metal deactivators, pour point depressants, viscosity modifiers, defoamers, cosolvents, packaging extenders, corrosion inhibitors, dyes, extreme pressure agents, etc. and mixtures thereof. A variety of additives are known and commercially available. These additives or their analogous compounds may be employed to prepare the lubricating oil composition of the present invention by conventional blending procedures.

[0086] When used, each of the aforementioned additives is used in a functionally effective amount to impart the desired properties to the lubricant. Thus, for example, if the additive is an ashless dispersant, the functionally effective amount of such an ashless dispersant will be an amount sufficient to impart the desired dispersion characteristics to the lubricant. Generally speaking, unless otherwise indicated, when used, the concentration of each of these additives may range from about 0.001% by weight to about 20% by weight, such as from about 0.010% by weight to about 10% by weight.

[0087] Example

[0088] The following non-limiting examples are provided.

[0089] Example 1

[0090] SAE 0W-8 lubricating oil is prepared by blending the following components together in a Group III base oil with a KV100 of 4 cSt:

[0091] a) 3.3 wt% of a mixture of borated and non-borated succinimide dispersants

[0092] b) A mixture of neutral calcium sulfonate (TBN = 17 mg KOH / g), overbased calcium sulfonate (TBN = 410 mg KOH / g) and overbased calcium phenate (TBN = 260 mg KOH / g) with a calcium content of 1240 ppm

[0093] c) Overbased magnesium sulfonate with 450 ppm magnesium content (TBN = 400 mg KOH / g)

[0094] d) A mixture of primary and secondary alkyl ZnDTPs with a phosphorus content of 660 ppm

[0095] e) 270 ppm molybdate succinimide as molybdenum

[0096] f) 0.3 wt% of an organic friction modifier (borated glycerol monooleate)

[0097] g) Small amounts of antioxidants, foam inhibitors and pour point depressants

[0098] Example 2

[0099] SAE 0W-8 lubricating oil is prepared by blending the following components together in a Group III base oil with a KV100 of 4 cSt:

[0100] a) 3.3 wt% of a mixture of borated and non-borated succinimide dispersants

[0101] b) A mixture of neutral calcium sulfonate (TBN = 17 mg KOH / g), overbased calcium sulfonate (TBN = 410 mg KOH / g) and overbased calcium phenate (TBN = 260 mg KOH / g) with a calcium content of 1240 ppm

[0102] c) Overbased magnesium sulfonate with 450 ppm magnesium content (TBN = 400 mg KOH / g)

[0103] d) A mixture of primary and secondary alkyl ZnDTPs with a phosphorus content of 660 ppm

[0104] e) 270 ppm molybdate succinimide as molybdenum

[0105] f) 0.3 wt% of an organic friction modifier (non-borated glycerol monooleate)

[0106] g) Small amounts of antioxidants, foam inhibitors and pour point depressants

[0107] Example 3

[0108] SAE 0W-8 lubricating oil is prepared by blending the following components together in a Group III base oil with a KV100 of 4 cSt:

[0109] a) 3.3 wt% of a mixture of borated and non-borated succinimide dispersants

[0110] b) A mixture of neutral calcium sulfonate (TBN = 17 mg KOH / g), overbased calcium sulfonate (TBN = 410 mg KOH / g) and overbased calcium phenate (TBN = 260 mg KOH / g) with a calcium content of 1240 ppm

[0111] c) Overbased magnesium sulfonate with 450 ppm magnesium content (TBN = 400 mg KOH / g)

[0112] d) A mixture of primary and secondary alkyl ZnDTPs with a phosphorus content of 660 ppm

[0113] e) 150 ppm molybdate succinimide expressed as molybdenum

[0114] f) 0.255 wt% of an organic friction modifier (borated glycerol monooleate)

[0115] g) Small amounts of antioxidants, foam inhibitors and pour point depressants

[0116] Comparative Example 1

[0117] SAE 0W-8 lubricating oil is prepared by blending the following components together in a Group III base oil with a KV100 of 4 cSt:

[0118] a) 3.3 wt% of a mixture of borated and non-borated succinimide dispersants

[0119] b) A mixture of neutral calcium sulfonate (TBN = 17 mg KOH / g), overbased calcium sulfonate (TBN = 410 mg KOH / g) and overbased calcium phenate (TBN = 260 mg KOH / g) with a calcium content of 1240 ppm

[0120] c) Overbased magnesium sulfonate with a magnesium content of 450 ppm (TBN = 400 mg KOH / g)

[0121] d) A mixture of primary and secondary alkyl ZnDTPs with a phosphorus content of 660 ppm

[0122] e) 270 ppm molybdate succinimide as molybdenum

[0123] f) 0.3 wt% of an organic friction modifier (borated glycerol monooleate)

[0124] g) 0.7 wt% MoDTC (10 wt% Mo)

[0125] h) Small amounts of antioxidants, foam inhibitors and pour point depressants

[0126] Comparative Example 2

[0127] SAE 0W-8 lubricating oil is prepared by blending the following components together in a Group III base oil with a KV100 of 4 cSt:

[0128] a) 3.3 wt% of a mixture of borated and non-borated succinimide dispersants

[0129] b) A mixture of neutral calcium sulfonate (TBN = 17 mg KOH / g), overbased calcium sulfonate (TBN = 410 mg KOH / g) and overbased calcium phenate (TBN = 260 mg KOH / g) with a calcium content of 1690 ppm

[0130] c) A mixture of primary and secondary alkyl ZnDTPs with a phosphorus content of 660 ppm

[0131] d) 150 ppm molybdate succinimide expressed as molybdenum

[0132] e) 0.255 wt% of an organic friction modifier (borated glycerol monooleate)

[0133] f) Small amounts of antioxidants, foam inhibitors and pour point depressants

[0134] Comparative Example 3

[0135] SAE 0W-8 lubricating oil is prepared by blending the following components together in a Group III base oil with a KV100 of 4 cSt:

[0136] a) 3.3 wt% of a mixture of borated and non-borated succinimide dispersants

[0137] b) A mixture of neutral calcium sulfonate (TBN = 17 mg KOH / g), overbased calcium sulfonate (TBN = 410 mg KOH / g) and overbased calcium phenate (TBN = 260 mg KOH / g) with a calcium content of 1690 ppm

[0138] c) A mixture of primary and secondary alkyl ZnDTPs with a phosphorus content of 660 ppm

[0139] d) 150 ppm molybdate succinimide expressed as molybdenum

[0140] e) 0.255 wt% of an organic friction modifier (borated glycerol monooleate)

[0141] f) 0.7 wt% MoDTC

[0142] g) Small amounts of antioxidants, foam inhibitors and pour point depressants

[0143] Fuel Economy Testing

[0144] The above lubricating oil compositions were tested for their fuel economy performance in 1) a gasoline powered engine (Toyota 2ZR-FXE) having a roller follower valve train and 2) a mechanical powered engine (Nissan MR20) having a direct acting valve train.

[0145] The detailed equipment configuration and conditions for the Toyota 2ZR-FXE test can be found in SAE paper 2019-01-2296. The test oil was preconditioned for 10 hours at an oil temperature of 88°C in an engine running at 1350 rpm. The fuel consumption of the test oil was measured over a 4-hour period in an engine running at 2100 rpm and 100 Nm for 15 minutes at an oil temperature of 85°C and compared to the fuel consumption of the baseline calibration (BC) oil. The viscosity determination values ​​of the BC oil used in the test method are as follows:

[0146] Table 2

[0147]

[0148] For the candidate oil tests, the fuel economy improvement (FEI) was calculated as the relative improvement (% change) over the average of the two BC oils as shown below. Higher FEI values ​​indicate better overall fuel economy performance.

[0149]

[0150] FEI: Fuel economy improvement (%)

[0151] FCBCB: Fuel consumption of BC oil before candidate test oil (kg / h)

[0152] FCCAN: Fuel consumption of candidate test oil (kg / h)

[0153] FCBCA: Fuel consumption of BC oil after candidate test oil (kg / h)

[0154] The detailed test procedure for the Nissan MR20 test can be found in JASO M365.

[0155] Table 3

[0156]

[0157] The Toyota 2ZR FXE FEI results in Table 3 show that the embodiments of the present invention exhibit excellent fuel economy performance in engines using roller follower type valve trains, even in the absence of MoDTC. In contrast, when MoDTC was added to the formulation, the fuel economy performance deteriorated significantly (compare Examples 1 and 3). Magnesium was also shown to contribute to fuel economy, while the lubricant containing only calcium detergent showed poor performance (compare Examples 2 and 3). When tested in a Nissan MR20 engine using a direct acting valve train rather than a roller follower type valve train, the fuel economy performance was slightly improved by adding MoDTC.

[0158] It should be understood that various modifications may be made to the embodiments disclosed herein. Therefore, the above description should not be interpreted as restrictive, but merely as an example of a preferred embodiment. For example, the functions described above and implemented as the best mode of operating the present invention are only for illustrative purposes. Without departing from the scope and spirit of the present invention, those skilled in the art may realize other arrangements and methods. In addition, those skilled in the art will expect other modifications within the scope and spirit of the appended claims.

Claims

1. A lubricating oil composition for an internal combustion engine having a roller follower type valve train, the lubricating oil composition comprising: a) a large amount of oil of lubricating viscosity; b) one or more magnesium detergents in an amount to provide 100 to 1000 ppm of magnesium to the lubricating oil composition; c) 0.1 wt % to 0.5 wt % of an organic friction modifier; and d) optional viscosity modifiers present in an amount not exceeding 0.5% by weight The lubricating oil composition is substantially free of molybdenum friction modifiers and has a total boron content ranging from 20 to 200 ppm.

2. The lubricating oil composition of claim 1, wherein the oil of lubricating viscosity is a Group III base oil having a kinematic viscosity at 100°C in the range of 4 cSt to 4.5 cSt.

3. The lubricating oil composition according to claim 1, wherein the organic friction modifier is glycerol monooleate or borated glycerol monooleate.

4. The lubricating oil composition of claim 2, wherein the viscosity improver is a non-dispersant comb polymethacrylate, a linear polymethacrylate, an olefin copolymer or a hydrogenated styrene-diene type copolymer.

5. The lubricating oil composition according to claim 1, further comprising a dispersant.

6. The lubricating oil composition of claim 5, wherein the dispersant is borated or non-borated.

7. The lubricating oil composition of claim 5, wherein the dispersant is a succinimide dispersant.

8. A method for improving the fuel efficiency of an internal combustion engine, wherein the method comprises: The internal combustion engine is lubricated with a lubricating oil composition comprising: a) a large amount of oil of lubricating viscosity; b) one or more magnesium detergents in an amount to provide 100 to 1000 ppm of magnesium to the lubricating oil composition; c) 0.1 wt % to 0.5 wt % of an organic friction modifier; and d) an optional viscosity modifier present in an amount not exceeding 0.5 wt. %; The lubricating oil composition is substantially free of molybdenum friction modifiers and has a total boron content ranging from 20 to 200 ppm.

9. The method of claim 8, wherein the oil of lubricating viscosity is a Group III base oil having a kinematic viscosity at 100°C in the range of 4 cSt to 4.5 cSt.

10. The method of claim 8, wherein the organic friction modifier is glyceryl monooleate or borated glyceryl monooleate.

11. The method of claim 8, wherein the viscosity improver is a non-dispersant comb polymethacrylate, a linear polymethacrylate, an olefin copolymer, or a hydrogenated styrene-diene type copolymer.

12. The method of claim 8, wherein the internal combustion engine includes a roller follower type valve train.

13. The method of claim 8, wherein the lubricating oil composition further comprises a dispersant.

14. The method of claim 13, wherein the dispersant is borated or non-borated.

15. The method of claim 15, wherein the dispersant is a succinimide dispersant.

Images