JP2005146285A - Lubricating oil composition - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a lubricating oil composition improving the cleanliness of pistons and having ≤1.0 mass% sulfated ash content. <P>SOLUTION: This lubricating oil composition is obtained by comprising, or is made by admixing a major amount of lubricating viscosity oil, and minor amounts of (A) a dispersant additive composition and (B) a detergent additive composition, wherein the oil composition gives a sulfated ash content of at most 1.0 mass%, for instance, 0.3-0.9 mass%, preferably 0.5-0.7 mass%; has a total base number (TBN) of 4-9.5, for instance, 5-9, preferably 6-8.5; has at least 0.08 mass%, for instance, 0.085-0.115 mass%, preferably, 0.09-0.10 mass% of nitrogen derived from the dispersant additive composition, based on the mass of the oil composition; and has at least 25 mmol, concretely, at least 28 mmol, for instance, ≤35 mmol of soap derived from the detergent additive composition per 1000 g of the oil composition. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to improved additives and lubricating oil compositions, such as multigrade lubricants, particularly those that exhibit good piston cleanliness.

Internal combustion engine crankcase lubricant compositions (or lubricants) are well known, and additives (or additive components) may be included in them to enhance their properties and performance. Are known.
Due to environmental concerns, constant efforts have been made to reduce particulate emissions in vehicle internal combustion engines, particularly compression ignition (diesel) internal combustion engines. One technique that has been used to reduce particulate emissions in diesel engines is a particulate collection device, which is designed to meet the requirements of the Euro IV emissions legislation. Introduced in all passenger cars and heavy-duty diesel vehicles. As the lubricant is consumed during use of the engine, the ash resulting from the metal-containing additives in the lubricant, primarily metal-containing detergents and antiwear agents, accumulates in the particulate matter collector. This ash cannot be removed without washing by either removing the collector from the engine and washing or blowing off the ash from the particulate collector with compressed air. The ash accumulated in the particulate matter collecting device may increase the pressure (back pressure) on the back surface of the collecting device. If this back pressure becomes severe, internal exhaust gas recirculation may result, resulting in fuel economy losses and ultimately engine failure. Lubricants require acid neutralization (provided by detergents) and lower wear protection performance (provided by ZDDP), so metal-containing additions that form ash in engine use The agent cannot simply be removed. The movement to reduce sulfate ash in the lubricant affects at least the available detergents that can be included, especially overbased detergents, and consequently the piston cleanliness, especially in high temperature diesel engines. High temperature piston cleanliness in diesel engines may be measured by the VWTDi test (according to CEC L-78-T-99 method). This test also gives an indication of the degree of piston ring sticking (called ring-sticking).

Therefore, formulators must carefully control the choice and amount of additives and base stocks in lubricating oil compositions to meet the limits set by governments and automotive organizations while achieving the required performance. .
US-A-5,102,566 describes a low sulfate ash lubricating oil composition comprising an ashless dispersant, an oil soluble antioxidant and an oil soluble dihydrocarbyl dithiophosphate.
EP-A-1167497 describes a lubricating oil composition having a low P content, a low sulfate ash content and a low sulfur content.
EP-A-1 266 955 describes the use of an ester base stock to improve piston cleanliness. EP-A-1 087 008 describes a method for improving a “ring-stick” by supplying a molybdenum-containing additive component to a lubricating oil composition.

Surprisingly, however, Applicants have found that an increased amount of soap and an increased amount of dispersant combination results in improved piston cleanliness in lubricating oil compositions having a sulfate ash content of 1.0% or less. I found out.
Thus, in a first aspect, the present invention comprises a major amount of lubricating oil and a minor amount of (A) a dispersant additive composition and (B) a detergent additive composition. Or a lubricating oil composition produced by mixing, wherein the oil composition provides 1.0% by weight or less of sulfate ash, for example 0.3 to 0.9% by weight, preferably 0.5 to 0.7% by weight, and the total base number (TBN ) 4 to 9.5, such as 5 to 9, preferably 6 to 8.5, and nitrogen derived from the dispersant additive composition is at least 0.08% by weight, for example 0.085 to 0.115% by weight, preferably based on the weight of the oil composition Wherein 0.09 to 0.10% by weight and the soap from the detergent additive composition has at least 25 millimoles (mmol), specifically at least 28 or 30 millimoles, such as 35 millimoles or less, per 1000 g of oil composition An oil composition is provided.

  The data contained herein indicates that the use of increased amounts of soap and dispersant unexpectedly improves the performance of the lubricating oil composition and provides less than 1.0 wt% ash. Further, a detergent additive based on mmol of soap per 1000 g of oil composition in the lubricating oil composition in an amount of dispersant additive composition (A) based on ppm of nitrogen in the lubricating oil composition A preferred ratio to the amount of composition (B) is 22: 1 to 46: 1, specifically 25: 1 to 40: 1, such as 27: 1 to 30: 1. This allows control of the disadvantages associated with: Dispersant additives (eg, collapse of elastomer seals) and detergent additives, specifically salicylate-based additives (eg, smoke control) possibility).

In a second aspect, the present invention provides a method of lubricating a compression ignition internal combustion engine comprising operating the engine and lubricating the engine with the lubricating oil composition of the first aspect.
In a third aspect, the present invention provides a method for improving the piston cleanliness and reducing the ring-stick tendency of a compression ignition internal combustion engine comprising adding the lubricating oil composition of the first aspect to the engine. .
In a fourth aspect, the present invention provides a combination comprising a compression ignition internal combustion engine, preferably a crankcase having a specific output of 25 kW / liter or more, and the lubricating oil composition of the first aspect.

In a fifth aspect, the present invention provides (1) a dispersant additive composition in an amount that provides at least 0.085 wt.% Nitrogen and (2) an amount of detergent that provides at least 25 mmol of soap per 1000 g of oil composition. Use of an additive composition in a lubricating oil composition for improving piston cleanliness of an internal combustion engine, wherein the oil composition provides a sulfate ash content of 1.0% by weight or less and a TBN of 4 to 9.5. I will provide a.
In a sixth embodiment, the present invention relates to 10 or 13.5 to 30% by weight, preferably 16 to 27% by weight, for example 18 to 25% by weight, based on the weight of the oil composition. If the oil composition contains a modifier and pour point depressant additive), the oily carrier liquid, the dispersant additive composition and An additive concentrate for the manufacture of a lubricating oil composition comprising a detergent additive composition is provided.

The features of the invention are described in detail below:
Lubricating Oil Composition The lubricating oil composition of the present invention is for lubricating the crankcase of an internal combustion engine, preferably a compression ignition (diesel) engine, more preferably a compression ignition passenger car engine. Crankcase lubricating oil compositions for diesel, particularly passenger cars, must be specifically formulated to meet performance requirements in such applications.
The lubricating oil composition of the present invention is a viscous grade SAE 5W-X or SAE 0W-X multi-grade oil composition, where X represents 20 and 30, and the characteristics of the different grades are SAE J300 classification Can be found.
In another embodiment of the present invention, the lubricating oil composition of the first embodiment has a NOACK volatility of 15% by weight or less, such as less than 13% by weight, preferably 11 as measured by CEC L-40-A-93. It is less than mass%. Generally, the NOACK volatility of the lubricating oil composition is 4 or more, for example 5 or more.

Furthermore, the lubricating oil composition of the present invention has a phosphorus content, preferably less than 0.09% by weight, such as less than 0.08% by weight, preferably less than 0.08% by weight, based on the weight of the oil composition, preferably from one or more zinc dithiophosphate additives. Is 0.01 to 0.07% by mass, particularly 0.03 to 0.06% by mass.
Regardless of other embodiments, the sulfur content of the lubricating oil composition of the present invention is preferably 0.25 wt% or less, more preferably 0.2 wt% or less, such as 0.05 to 0.15 wt%, based on the weight of the oil composition. It is.
The molybdenum content of the lubricating oil composition may be 300 ppm or less, preferably 10 to 200 ppm, particularly 50 to 175 ppm (mass) based on the mass of the oil composition.

Boron-containing additives may also be present in the lubricating oil composition. In such cases, the boron content in the oil composition is 150 ppm or less, preferably 10 to 100 ppm, in particular 25 to 75 ppm (mass), based on the weight of the oil composition.
The amounts of phosphorus, sulfur, molybdenum and boron are measured by the method of ASTM D5185, “TBN” is the total base number measured by ASTM D2896, the amount of nitrogen is measured by the method of ASTM D4629, and Sulfate ash is measured by the method of ASTM D874.
The lubricating oil composition preferably meets the performance requirements of at least ACEA B2-98, more preferably at least ACEA B1-98, such as at least ACEA B3-98, especially at least ACEA B4-98, for light diesel engines.

Lubricating viscous oil Lubricating viscous oil is the main liquid component of a lubricating oil composition. Lubricating viscous oils include (a) oil added to the additive concentrate or additive package, and (b) oil present in the additive concentrate or additive package.
The lubricating viscous oil may be a synthetic or mineral oil selected from the group consisting of Group I, II, III, IV and V basestocks, and mixtures thereof.
Base stocks may be manufactured using a variety of different methods, including but not limited to distillation, solvent purification, hydrogen processing, oligomerization, esterification and repurification. is not.

The American Petroleum Institute (API) 1509 “Engine Oil Licensing and Certification System” 14th edition, December 1996 states that all base stocks fall into five general categories:
Group I base stocks have a saturation of less than 90% and / or a sulfur content of greater than 0.03% and a viscosity index of 80 or more and less than 120;
Group II base stock has a saturation of 90% or more, a sulfur content of 0.03% or less, and a viscosity index of 80 or more and less than 120;
Group III base stocks have a saturation level of 90% or higher, a sulfur content of 0.03% or lower, and a viscosity index of 120 or higher;
Group IV base stocks are polyalphaolefins (PAO); and Group V base stocks include all other base stocks not included in Group I, II, III, or IV.
Group IV base stocks, or polyalphaolefins (PAOs), are generally hydrogenated oligomers of alpha olefins, with the most important methods of oligomerization being free radical processes, Ziegler catalysts, cationic and Friedel-Craft catalysts. is there.

Group V base stocks are preferred in ester formation and tend to be commercially available. Examples include polyol esters such as pentaerythritol ester, trimethylolpropane ester and neopentylglycol ester; diesters; 36 carbon dimer acid ester; trimellitic acid ester, ie 1,2,4-benzenetricarboxylate; And phthalic acid esters, ie 1,2-benzenedicarboxylate. The acid from which the ester is produced is preferably a monocarboxylic acid of the general formula RCO ₂ H, where R represents a branched, linear or mixed alkyl group. Such acids may have, for example, 6 to 18 carbon atoms.

Preferably, the oil of lubricating viscosity is selected from any one of Group I-V base stocks and mixtures thereof, provided that the sulfur content of the oil is 0.1% by weight or less, for example 0.05, based on the weight of the oil. It is on condition that it is below mass%, More preferably, it is 0.005-0.03 mass%.
Particularly preferred are lubricating viscous oils conveniently comprising a Group III base stock in an amount of at least 20% by weight, for example at least 40% by weight, more preferably 55-90% by weight, based on the weight of the oil composition. is there.
In a preferred embodiment, the lubricating oil comprises a Group III base stock and a Group V base stock in the form of an ester. The amount of group V base stock in the form of an ester, based on the weight of the oil composition, is not more than 15% by weight, such as 0.5-15% by weight, more preferably 1 or 2-15% by weight, specifically 3 -15% by weight, more specifically 3-10% by weight, conveniently 3-8% by weight, for example 5-8% by weight, is preferred. Group I, Group II or Group IV base stocks or mixtures thereof are used as lubricating oils as diluent or carrier liquids for additive components and additive concentrates used in making the lubricating oil compositions of the present invention. May be present in minor amounts.

More preferably, the lubricating oil consists essentially of a Group III base stock and a Group V base stock in the form of an ester, but a small amount, eg, 25 wt% or less, such as 20 wt%, based on the weight of the total basestock. %, Preferably 10% by weight or less, conveniently 5% by weight or less of other base stocks, such as Group I, Group II or Group IV base stocks or mixtures thereof.
The test method used to define the above group is one of ASTM D2007 for saturation, ASTM D2270 for viscosity index, and ASTM D2622, 4294, 4927 and 3120 for sulfur.
Dispersant additive composition

Dispersants (or dispersant additives), e.g. ashless (i.e. metal-free) dispersants, hold solid and liquid contaminants resulting from oxidation during use in the suspension, and thus metal parts. Prevent sludge agglomeration and sediments or deposits at the bottom; they contain long-chain hydrocarbons at the polar tip that can be combined with the dispersed particles to provide oil solubility. A notable group is a hydrocarbon-substituted succinimide.
In general, ashless dispersants do not substantially form ash upon combustion, in contrast to metal-containing (and thus ash-forming) dispersants. Also, the borate metal-free dispersant is considered herein as an ashless dispersant. “Substantially no ash” means that the dispersant may give a trace amount of ash in combustion, but the amount does not actually or obviously affect the performance of the dispersant.
The dispersant additive composition may contain one or more dispersants.

  The ashless dispersant of the present invention comprises an oil-soluble polymeric long-chain backbone having functional groups that can bind to the particles to be dispersed. In general, such dispersants often have an amine, amine-alcohol or amide polar component attached to the polymer backbone through a bridging group. Ashless dispersants may be selected, for example, from the following: oil-soluble salts, esters, amino-esters, amides, imides and oxazolines of long chain hydrocarbon-substituted mono- and poly-carboxylic acids or their anhydrides A thiocarboxylate derivative of a long chain hydrocarbon; a long chain aliphatic hydrocarbon having a polyamine directly attached thereto; and a Mannich condensation product formed by condensing a long chain substituted phenol with formaldehyde and a polyalkylene polyamine. Suitable dispersants include, for example, derivatives of long chain hydrocarbyl substituted carboxylic acids whose hydrocarbyl groups tend to have a number average molecular weight of less than 15,000, such as less than 5,000; examples of such derivatives As derivatives of high molecular weight hydrocarbyl-substituted succinic acid. Such hydrocarbyl-substituted carboxylic acids may be derivatized with, for example, nitrogen-containing compounds, conveniently polyalkylene polyamines or amine alcohols or amides or esters. Particularly preferred dispersants are reaction products of polyalkyleneamines and alkenyl succinic anhydrides. Examples of specifications disclosing dispersants of the last mentioned type include US-A-3 202 678, 3 154 560, 3 172 892, 3 024 195, 3 024 237, 3 219 666, 3 216 936 and There is BE-A-662 875.

The dispersant may comprise polyisobutenyl succinimide made using high vinylidene polyisobutene (PIB), for example, where more than 80% of the terminal olefin groups have only hydrogen groups. When such a dispersant is used, the total chlorine content of the oil composition of the present invention appears to be less than 50 pm as measured by XRF.
The dispersants of the present invention are preferably non-polymeric (eg, mono- or bis-succinimide).

The dispersant of the present invention may be borated as desired. Such dispersants can be borated by conventional methods as generally taught in US Pat. Nos. 3,087,936, 3,254,025 and 5,430,105. The borateization of the dispersant involves the conversion of the acyl nitrogen containing dispersant into a boron compound, such as boron oxide, boron halide boron acid and an ester of boric acid, and a boron atomic ratio for each mole of acylated nitrogen composition. Easily achieved by processing in an amount sufficient to provide from about 0.1 to about 20.
Ashless succinimide or a derivative thereof, obtained from polyisobutenyl succinic anhydride produced from polybutene and maleic anhydride by a thermal reaction method using neither chlorine nor chlorine atom-containing compounds Those are preferred dispersants.
Alternatively or additionally, dispersancy may be provided by polymeric compounds that can provide viscosity index enhancement and dispersibility, such compounds may be added to the dispersant viscosity index improver additive or multiple. It is known as a functional viscosity index improver. Such polymers differ from conventional viscosity index improvers in that they provide performance characteristics such as dispersibility and / or antioxidant properties in addition to viscosity index improvers.

Dispersant olefin copolymers and dispersant polymethacrylates are examples of dispersant viscosity index improver additives. Dispersant viscosity index improver additives are made by chemically combining various functional ingredients such as amines, alcohols and amides to the polymer, which is preferably gel permeation chromatography or light scattering methods. Tends to have a number average molecular weight of at least 15,000, for example 20,000 to 600,000. The polymers used may be those described below in connection with the viscosity modifier. Thus, amine molecules may be included to provide dispersibility and / or antioxidant properties, while phenolic molecules may be included to improve antioxidant properties. Thus, specific examples include ethylene-propylene interpolymers that are post-grafted with an active monomer such as maleic anhydride and then derivatized with, for example, an alcohol or an amine. When a dispersant viscosity modifier is used in the present invention, the nitrogen content of the lubricating oil composition also includes those derived from the dispersant viscosity modifier. An example of a dispersant viscosity modifier is Hitec® 5777 manufactured and sold by Ethyl Corp.
EP-A-24146 and EP-A-0 854 904 describe examples of dispersants and dispersant viscosity index improvers and are therefore included herein.
Conveniently, the dispersant additive composition comprises one or more dispersants, preferably borate and non-borate dispersants.

Detergent additive composition Detergent (or detergent additive) reduces the formation of piston deposits such as hot varnish and lacquer deposits by retaining fine solids in the suspension in the engine; , May have acid neutralizing properties. The detergent comprises a metal salt of an organic acid, referred to herein as soap or surfactant.
The detergent has a polar tip, ie a metal salt of an organic acid, with a long hydrophobic end for oil solubility. Thus, generally organic acids have one or more functional groups for reaction with metals, such as OH or COOH or SO ₃ H and hydrocarbyl substituents. If the detergent contains an excess of metal with respect to the theoretical amount required for neutralization of the organic acid, the detergent may be overbased. This excess is in the form of a colloidal dispersion with metal salts of organic acids in the micellar structure, generally in the form of metal carbonates and / or hydroxides.

(式中、Rはヒドロカルビル基を表し、yは1〜4を表す)。yが1より大きい場合、ヒドロカルビル基は、同じでも異なっていてもよい。
フェノールは、多くの場合、硫化された形態で使用される。硫化方法の詳細は当業者に公知であり、例えばUS-A-4,228,022及びUS-A-4,309,293を参照されたい。 Examples of organic acids include their sulfonic acids, phenols and sulfurized derivatives and carboxylic acids such as aromatic carboxylic acids.
The phenol may be non-sulfurized or preferably sulfurized. Furthermore, as used herein, the term “phenol” includes phenols containing more than one hydroxyl group (eg, alkyl catechol) or fused aromatic rings (eg, alkyl naphthol) and chemically modified phenols such as alkylene. Cross-linked phenols and Mannich base condensed phenols; and saligenin type phenols (produced from the reaction of phenol and aldehyde under basic conditions).
Preferred phenols are represented by the general formula:

(Wherein R represents a hydrocarbyl group and y represents 1 to 4). When y is greater than 1, the hydrocarbyl groups may be the same or different.
Phenol is often used in a sulfurized form. Details of the sulfurization process are known to those skilled in the art, see for example US-A-4,228,022 and US-A-4,309,293.

In the above general formula, the hydrocarbyl group represented by R is conveniently an alkyl group, conveniently having 5 to 100, preferably 5 to 40, in particular 9 to 12, carbon atoms in all R groups. The average carbon number is preferably at least about 9 to ensure a suitable oil solubility. Preferred alkyl groups are nonyl (eg tripropylene) or dodecyl (eg tetrapropylene) groups.
As mentioned above, the term “phenol” as used herein includes phenols modified by chemical reaction with, for example, aldehydes and Mannich base condensed phenols.
Examples of aldehydes that may be modified with phenol include formaldehyde, propionaldehyde, and butyraldehyde. A preferred aldehyde is formaldehyde. Aldehyde-modified phenols suitable for use according to the invention are described, for example, in US-A-5 259 967 and WO 01/74751.

Mannich base condensed phenol is produced by the reaction of phenol, aldehyde and amine. Examples of suitable Mannich base condensed phenols are described in GB-A-2 121 432.
In general, the phenol may contain substituents other than those described above. Examples of such a substituent include a methoxy group and a halogen atom.
Preferred phenols are their sulfurized derivatives.
In general, sulfonic acids are hydrocarbyl substituted, specifically alkyl substituted, sulfonation of aromatic hydrocarbons such as those obtained from fractionation of petroleum by distillation and / or extraction or by alkylation of aromatic hydrocarbons. Is obtained. The alkylaryl sulfonic acid generally has from about 22 to about 100 carbon atoms. The sulfonic acids may be substituted on the aromatic component by more than one alkyl group, for example, they may be dialkylaryl sulfonic acids. Preferably the number average molecular weight of the sulfonic acid is 350 or more, more preferably 400 or more, especially 500 or more, for example 600 or more. The number average molecular weight may be measured by ASTM D3712.

Other types of sulfonic acids that may be used in accordance with the present invention include alkylphenol sulfonic acids. Such sulfonic acids may be sulfurized.
Carboxylic acids include mono- and dicarboxylic acids. Preferred monocarboxylic acids are those having 8 to 30 carbon atoms, especially 8 to 24 carbon atoms. (In the present specification, when the number of carbon atoms of a carboxylic acid is indicated, the carbon atom of the carboxyl group is included in the number). Examples of monocarboxylic acids include isooctanoic acid, stearic acid, oleic acid, palmitic acid and behenic acid. If desired, isooctanoic acid may be used in the form of a mixture of C8 acid isomers sold under the trade name “Cekanoic” by Exxon Chemical. Other suitable acids are those having a tertiary substituent at the α-carbon atom and dicarboxylic acids having two or more carbon atoms separating the carboxyl groups. Furthermore, dicarboxylic acids having more than 35 carbon atoms, for example, 36 to 100 carbon atoms are also suitable. Unsaturated carboxylic acids may be sulfided.

A preferred type of carboxylic acid is an aromatic carboxylic acid. The aromatic component of the aromatic carboxylic acid can include heteroatoms such as nitrogen and oxygen. Preferably, the component contains only carbon atoms; more preferably, the component has 6 or more carbon atoms; for example, benzene is a preferred component. The aromatic carboxylic acid may include one or more aromatic components, such as one or more benzene rings, which are fused or linked by alkylene bridges.
The carboxyl component may be bonded directly or indirectly to the aromatic component. Preferably, the carboxylic acid group is directly bonded to a carbon atom on the aromatic moiety, such as a carbon atom on the benzene ring.

More preferably, the aromatic component also includes a second functional group, such as a hydroxy group or a sulfonate group, that can be directly or indirectly bonded to a carbon atom on the aromatic component.
Preferred examples of aromatic carboxylic acids are salicylic acid and their sulfurized derivatives, such as hydrocarbyl substituted salicylic acid and their derivatives.
For example, methods for sulfiding hydrocarbyl substituted salicylic acids are known to those skilled in the art.
In general, salicylic acid is produced by carboxylation of phenoxides, for example by the Kolbe-Schmitt method, in which case it will generally be obtained in a mixture with non-carboxylated phenol in a diluent.
A preferred substituent for oil soluble salicylic acid is an alkyl substituent. In alkyl-substituted salicylic acid, the alkyl group conveniently has 5 to 100 carbon atoms, preferably 9 to 30 carbon atoms, especially 14 to 20 carbon atoms. When more than one alkyl group is present, the average number of carbons in all alkyl groups is preferably at least 9 to ensure adequate oil solubility.

Metal detergents may be neutral or overbased, and such conditions are known in the art. The detergent additive component may include one or more detergent additives, which may be neutral detergents, overbased detergents or a mixture of both.
The total base number (TBN) of the detergent is 15-600.
The detergent of the present invention may be a salt of one type of organic acid or a salt of more than one type of organic acid, for example a hybrid complex detergent.
A hybrid composite detergent is a detergent in which the basic material within the detergent, for example colloidal metal carbonate, is stabilized by more than one type of metal salt of an organic acid. One skilled in the art will recognize that a single type of organic acid may comprise a mixture of the same type of organic acid. For example, the sulfonic acid may include a mixture of sulfonic acids of various molecular weights. Such organic acid compositions are considered one type. Thus, complex detergents are distinguished from a mixture of two or more separate detergents, for example, such a mixture comprising an overbased calcium salicylate detergent and an overbased calcium phenate detergent. It is a mixture.

  There are descriptions in the art of examples of overbased complex detergents. For example, International Patent Application Publication Nos. WO 97/46643/4/5/6 and 7 are included herein with respect to the description and definition of hybrid composite detergents, including more than one acidic organic compound and A hybrid complex is described that is produced by neutralizing a mixture of basic metal compounds and then overbasing the mixture. Thus, the individual basic materials of the detergent are stabilized by many organic acid types. Examples of hybrid composite detergents include calcium phenate-salicylate-sulfonate detergents, calcium-phenate-sulfonate detergents and calcium phenate-salicylate detergents.

EP-A-0 750 659 is a calcium salicylate phenate complex produced by carboxylating calcium phenate, followed by sulfurization and overbasing a mixture of calcium salicylate and calcium phenate. It is described. Such a complex may be referred to as a “phenalate”.
The detergent additive composition may comprise two or more detergents, such as alkali metals, such as sodium, detergents and alkaline earth metals, such as calcium and / or magnesium, detergents. For the avoidance of doubt, the detergent additive composition may contain an ashless detergent, i.e. a metal-free detergent, generally in the form of an organic salt of an organic acid, in which case the soap is organic. A soap derived from such a detergent, corresponding to an acid salt, provides a predetermined amount of soap in the lubricating oil composition of the present invention. Preferably, the detergent is metal-containing and Group 1 and Group 2 metals are preferred as the metals in the detergent, more preferably calcium and magnesium, especially calcium.

Preferably, the detergent composition comprises at least one overbased metal detergent, regardless of whether the detergent comprises one type of organic acid metal salt or more than one type of organic acid metal salt. Contains agents.
A detergent addition comprising, preferably consisting essentially of, at least one metal detergent based on one or more organic acids which do not contain sulfur, such as carboxylic acid, salicylic acid, alkylene bridged phenol and Mannich base condensed phenol An agent composition is preferred. Specifically, salicylic acid based detergents have been found to be particularly effective. Thus, a detergent additive composition comprising only a metal, preferably calcium, salicylate-based detergent, is advantageous whether it is neutral or overbased, for example overbased calcium salicylate. It is.

The detergent additive composition preferably comprises two or more detergents, preferably at least one detergent having a TBN greater than 150 and at least one detergent having a TBN of 150 or less.
Preferably, 35 mmol% or less, for example 5-30 mmol%, preferably 10-25 mmol% soap is derived from one or more detergents with a TBN higher than 150.
Applicants have found that a detergent additive composition comprising a calcium salicylate having a TBN of 150-200 and a calcium salicylate having a TBN of 80 or less is preferred. Preferably, in the detergent additive composition, the amount of calcium salicylate having a TBN of 150-200 is 35 mmol% or less of soap per 1000 g of oil composition relative to the lubricating oil composition, such as 5-30 mmol%, preferably 10-25 mmol% is given.

In another embodiment, a detergent additive composition comprising at least one metal salicylate, preferably calcium salicylate, more preferably a calcium salicylate having a TBN of 150 or less, such as 100 or less, preferably 80 or less, is a high temperature. Especially effective for piston cleanliness.
If the composition comprises a detergent and one or more additive adjuvants, then the detergent may be separated from the additive adjuvant, for example by using dialysis techniques, and then The detergent may be analyzed as described above to determine the metal ratio. Background information on suitable dialysis techniques can be found in “Chromatography in Petroleum Analysis” by Amos, R. and Albaugh, E. W, Altgelt, K. H and Gouw, TH, Eds., Pages 417-421, Marcel Dekker Inc., New York And Basel, 1979.

Methods for measuring the amount of soap are known to those skilled in the art. EP-A-0 876 449 describes a method for determining the number of moles of calcium salt of an organic acid, the disclosure of which is included here.
Those skilled in the art will also know from the information about the raw materials used to produce the detergent (eg, the amount and type of organic acid) and the information about the amount of detergent used in the final oil composition, The amount of soap in the object can be calculated. Analytical methods (eg potentiometric titration and chromatography) can be used to determine the amount of soap.
It is well recognized by those skilled in the art that the method of measuring the amount of metal salt of an organic acid (also known as soap) is at best an approximation and that different methods are not always considered to give the same result accurately. However, they are accurate enough to allow the practice of the present invention.

Additive concentrates Additive concentrates are a convenient means of handling more than one additive prior to their use and to facilitate dissolution or dispersion of the additive in the lubricant composition. . When producing a lubricant composition that contains more than one type of additive (sometimes referred to as an “additive component”), each additive is placed separately. However, in many cases, it is convenient to include the additive as an additive concentrate that includes two or more additives (so-called additive “packages” (also referred to as “adpacks”)).

  In the manufacture of lubricating oil compositions, it is common practice to introduce additives, and therefore in the form of additive concentrates containing additives. If many additives are used, it may be desirable, but not essential, to produce one or more additive concentrates (also known as additive packages) containing the additive. In general, several additives, except for viscosity modifiers, multifunctional viscosity modifiers and pour point depressants, can be added simultaneously to the lubricating oil to form a lubricating oil composition. The dissolution of the additive concentrate in the lubricating oil may be facilitated by diluents or solvents and by mixing with gentle heating, but it is not essential. Generally, when an additive concentrate is combined with a predetermined amount of lubricating oil, the additive concentrate will be formulated to include the additive in an appropriate amount that provides the desired concentration in the final composition. Let's go. If necessary, the viscosity modifier, multifunctional viscosity modifier, and pour point depressant are then added separately to form a lubricating oil composition.

Examples of other additives include rust inhibitors, antiwear agents, antioxidants, corrosion inhibitors, friction modifiers, pour point depressants, antifoaming agents, viscosity modifiers and surfactants. .
The additive concentrate may contain 1 to 90% by weight of additive, for example 10 to 80% by weight, preferably 20 to 80% by weight, more preferably 40 to 70% by weight, based on the active ingredient, The remainder is an oily carrier or diluent (eg, a viscous oil). The final lubricating oil composition may generally contain 5-40% by weight of additive concentrate.

  The amount of additive in the final lubricating oil composition generally depends on the type of oil composition, e.g. heavy duty diesel engine lubricating oil compositions are based on the weight of the oil composition and the additive 10-40 % By weight, more preferably 15 to 35% by weight, for example 25 to 30% by weight (including diluent). Passenger car engine lubricating oil compositions, such as gasoline or diesel engine oil compositions, are based on the weight of the oil composition, for example additive 10 or 13.5 to 30% by weight, preferably 16 to 27% by weight, for example 18 to 25% by weight. Tend to have%. The above amounts represent other than viscosity modifiers and pour point depressant additives.

In general, the viscosity of the additive concentrate is higher than that of the lubricating oil composition. In general, the kinematic viscosity at 100 ° C. of the additive concentrate is at least 50 mm ² s ⁻¹ , for example 100 to 200 mm ² s ⁻¹ , preferably 120 to 180 mm ² s ⁻¹ (or cSt). .
Accordingly, the method of producing the lubricating oil composition of the present invention comprises mixing a lubricating viscous oil and an additive concentrate comprising one or more additives or two or more additives and then other additive components such as Mixing the viscosity modifier, the multifunctional viscosity modifier and the pour point depressant may be included.

  Viscosity index improvers (or viscosity modifiers) impart high and low temperature operability to lubricating oils, enable shear stability to be maintained at high temperatures, and exhibit acceptable viscosity or fluidity at low temperatures. Compounds suitable for use as viscosity modifiers are generally high molecular weight hydrocarbon polymers such as polyisobutylene, copolymers of ethylene and propylene and higher alpha olefins; polyesters such as polymethacrylate; hydrogenated poly (styrene-co- Butadiene or -isoprene) polymers and modifications (eg, star polymers); and esterified poly (styrene-co-maleic anhydride) polymers. Generally, the oil-soluble viscosity adjusting polymer has a number average molecular weight of at least 15,000 to 1,000,000, preferably 20,000 to 600,000, as measured by gel permeation chromatography or light scattering. The disclosure of Chapter 5 of “Chemistry & Technology of Lubricants”, 1st edition by R.M. Mortier and S.T. Orzulik, 1992, Blackie Academic & Professional, is hereby included. The VM used may have a single function or be multifunctional.

  Friction modifiers include boundary additives that lower the coefficient of friction and thus improve fuel economy. Examples include oil-soluble amines, amides, imidazolines, amine oxides, amidoamines, nitriles, alkanolamides, alkoxylated amines and ether amines and polyol esters, polycarboxylic acid esters, and glycerol monoesters of higher fatty acids such as Glycerol monooleates; butanediol esters of dimerized unsaturated fatty acids; oxazoline compounds; and ethoxylated tallow amines and ethoxylated tallow ether amines. Molybdenum-containing compounds are examples of friction modifiers. Conventionally, one or more organic friction modifiers are used in an amount of 0.1-0.5% by weight, for example 0.2-0.4% by weight, based on the weight of the oil composition.

Antiwear agents reduce friction and excessive wear and are usually based on compounds containing sulfur or phosphorus or both. Dihydrocarbyl dithiophosphate metal salts are often used as antiwear and antioxidant agents. The metal may be an alkali or alkaline earth metal, or aluminum, lead, tin, molybdenum, manganese, nickel or copper. Zinc salts (ZDDP) are most commonly used in lubricating oils in amounts of 0.1 to 10% by weight, preferably 0.2 to 2% by weight, based on the total weight of the lubricating oil composition. They form, according to known techniques, firstly dihydrocarbyl dithiophosphate (DDPA) by reaction of one or more alcohols or phenols with P ₂ S ₅ and then neutralizing the formed DDPA with a zinc compound. You may manufacture by. For example, dithiophosphoric acid may be produced by reacting a mixture of primary and secondary alcohols having 1 to 18 carbon atoms, preferably 2 to 12 carbon atoms. Alternatively, multiple dithiophosphoric acids can be prepared when one hydrocarbyl group is completely secondary in character and the other hydrocarbyl group is completely primary in character. To make the zinc salt, basic or neutral zinc compounds can be used, but hydroxides and carbonates are most commonly used. Commercial additives often contain excess zinc due to the use of excess basic zinc compounds in the neutralization reaction.

  ZDDP provides excellent wear protection and antioxidant function at a relatively low cost. Preferably, the zinc dithiophosphate composition comprising one or more zinc dithiophosphates specifically comprises a mixture of primary and secondary alkyl groups, wherein the secondary alkyl groups are in a majority molar ratio based on the amount of alkyl groups, For example, those that are at least 60 mol%, conveniently at least 75 mol%, more specifically at least 85 mol% are useful in the present invention. Preferably, the zinc dithiophosphate composition has 90 mol% secondary alkyl groups and 10 mol% primary alkyl groups.

  Antioxidants increase the composition's resistance to oxidation and may work by combining and modifying the peroxide, harming them by decomposing the peroxide or by deactivating the oxidation catalyst. To. They are classified as radical scavengers (eg, sterically hindered phenols, secondary aromatic amines and organic copper salts); hydroperoxide decomposers (eg, organic sulfur and organophosphorus additives); and multifunctional agents. Also good. Such antioxidants (or antioxidants) are hindered phenols, aromatic amine compounds, alkaline earth metals and metal-free alkylphenol thioesters, preferably having an alkyl side chain of 5 to 12 carbon atoms Ashless alkylene-bridged phenols, phosphosulfurized and sulfurized hydrocarbons, phosphorus esters, metals and metal-free thiocarbamates and their derivatives, oil-soluble copper compounds described in US 4,867,890, and molybdenum-containing compounds. It is done. In the practice of the present invention, the use of certain antioxidants or otherwise may provide certain advantages. For example, in one embodiment, an antioxidant comprising a secondary aromatic amine and a hindered phenol having an ester group is preferably used.

Preferably, aromatic amines such as diphenylamine and hindered phenol compounds such as 3,5-bis (alkyl) -4-hydroxyphenyl carboxylic acid esters such as IRGANOX® L135 sold by Chiba Specialty Chemicals. Useful. Usually, one or more antioxidants are used in an amount of 0.1 to 0.8% by weight, for example 0.2 to 0.6% by weight, preferably 0.3 to 0.5% by weight, based on the weight of the oil composition.
Molybdenum-containing compounds useful in the present invention, preferably molybdenum-sulfur compounds, may be mononuclear or polynuclear. If the compound is polynuclear, the compound comprises a molybdenum core consisting of non-metallic atoms such as sulfur, oxygen and selenium, preferably consisting essentially of sulfur.
In order to make the molybdenum-sulfur compound oil soluble or oil dispersible, one or more ligands are attached to the molybdenum atoms in the compound. Ligand binding includes binding by electrostatic interactions in the case of counterions and forms of binding intermediate between covalent and electrostatic binding. Ligands within the same compound may be bound differently. For example, the ligand may be a covalent bond and the other ligand may be electrostatically bound.

Preferably, the or each ligand is monoanionic and examples of such ligands are dithiophosphates, dithiocarbamates, xanthates, carboxylates, thioxanthates, phosphates and their hydrocarbyls, preferably alkyl derivatives. Is mentioned. Preferably, when the molybdenum-sulfur compound is a polynuclear compound, the ratio of the number of molybdenum atoms to the number of monoanionic ligands in the core (which can make the compound oil-soluble or oil-dispersible) is greater than 1. Pair 1, for example at least 3 to 2.
The oil solubility or oil dispersibility of molybdenum-sulfur compounds may be influenced by the total number of carbons present in the ligands of all compounds. The total number of carbons present in all of the hydrocarbyl groups of the ligand of the compound will generally be at least 21, such as 21 to 800, such as at least 25, at least 30 or at least 35. For example, the number of carbons in each alkyl group will generally be 1-100, preferably 1-40, more preferably 3-20.

(式中、R₁〜R₄は、独立して炭素数1〜24の直鎖、分岐鎖又は芳香族ヒドロカルビル基を示し；X₁〜X₄は、独立して酸素原子又は硫黄原子を示す)。4つのヒドロカルビル基、R₁〜R₄は互いに同じでも異なっていてもよい。 Examples of molybdenum-sulfur compounds include dinuclear molybdenum-sulfur compounds and trinuclear molybdenum-sulfur compounds.
Examples of dinuclear molybdenum-sulfur compounds are represented by the following general formula:

(In the formula, R _{1 to} R ₄ independently represent a linear, branched or aromatic hydrocarbyl group having 1 to 24 carbon atoms; X _{1 to} X ₄ independently represent an oxygen atom or a sulfur atom. ). The four hydrocarbyl groups, R _{1 to} R _4, may be the same or different from each other.

  In a preferred embodiment, the molybdenum-sulfur compound is an oil-soluble or oil-dispersible trinuclear molybdenum-sulfur compound. Examples of trinuclear molybdenum-sulfur compounds are disclosed in WO98 / 26030, WO99 / 31113, WO99 / 66013, EP-A-1 138 752, EP-A-1 138 686 and European Patent Application No. 02078011, Each of which is hereby incorporated by reference, particularly with respect to the properties of the molybdenum compounds or additives disclosed herein.

Preferably, the trinuclear molybdenum-sulfur compound is represented by the general formula Mo ₃ S _k E _x L _n A _p Q _z , where:
k is an integer of at least 1;
E represents a nonmetallic atom selected from oxygen and selenium:
x may be 0 or an integer, preferably k + x is at least 4, more preferably 4-10, such as 4-7, most preferably 4 or 7;
L represents a ligand that confers oil solubility or oil dispersibility on the molybdenum-sulfur compound, preferably L is a monoanionic ligand;
n is an integer from 1 to 4,
A represents an anion other than L if L is an anionic ligand;
p can be 0 or an integer;
Q represents a neutral electron donor compound;
z is 0 to 5 and includes non-theoretical values.

  Formation of the trinuclear molybdenum-sulfur compound requires, for example, the selection of a suitable ligand (L) and other anions (A) depending on the number of sulfur and E atoms present in the core, i.e. sulfur atoms, One skilled in the art will recognize that the total anion number provided by the E atom, if present, and L and A, if present, must be -12. If the anion number is greater than -12, the trinuclear molybdenum-sulfur compound may have other than molybdenum, for example (alkyl) ammonium, amine or sodium.

Examples of Q include water, alcohol, amine, ether and phosphine. The electron donor compound, Q, is believed to be present merely to fill the empty coordination site on the trinuclear molybdenum-sulfur compound.
Examples of A may be any valence, for example, monovalent and divalent, and include disulfides, hydroxides, alkoxides, amides and thiocyanates or derivatives thereof, with preferred A being a disulfide ion. .
Preferably, L is a monoanionic ligand, such as dithiophosphate, dithiocarbamate, xanthate, carboxylate, thioxanthate, phosphate and hydrocarbyl, preferably alkyl, derivatives thereof. When n is 2 or more, the ligands may be the same or different.

In certain embodiments, independent of other embodiments, k is 4 or 7, n is 1 or 2, L is a monoanionic ligand, p is electrically neutral on an anionic charge-based compound on A X and z are 0 respectively.
In a further embodiment, independent of other embodiments, k is 4 or 7, L is a monoanionic ligand, n is 4, and p, x, and z are 0, respectively.

Molybdenum-sulfur cores, such as the structures shown in (I) and (II) above, are linked together by one or more multidentate ligands, i.e. ligands with more than one functional group capable of binding to a molybdenum atom. And oligomers may be formed. Molybdenum-sulfur additives containing such oligomers are considered within the scope of the present invention.
Other examples of molybdenum containing compounds include molybdenum carboxylate and molybdenum nitrogen complex, both of which may be sulfided.
In some embodiments, molybdenum-containing compounds such as trinuclear molybdenum dithiocarbamates are preferred.

  Boron may also be present in the lubricating oil composition of the present invention. Boron-containing additives may be produced by reacting boron compounds with oil-soluble or oil-dispersible additives or compounds. Examples of boron compounds include boron oxide, boron oxide hydrate, boron trioxide, boron trifluoride, boron tribromide, boron trichloride, boron acid, such as boronic acid. ), Boric acid, tetraboric acid and metaboric acid, borohydride, boron amide and various esters of boric acid. Examples of boron-containing additives include borate dispersant; borate dispersant VI improver; alkali metal or mixed alkali metal or alkaline earth metal borate; borate overbased metal detergent; borate epoxide; borate ester; Boric acid esters; and boric acid amides. A preferred boron-containing additive is a borate dispersant.

A rust inhibitor selected from the group consisting of nonionic polyoxyalkylene polyols and esters thereof, polyoxyalkylene phenols and anionic alkyl sulfonic acids may be used.
Copper and lead supported corrosion inhibitors may be used, but they are generally not required for the formulations of the present invention. In general, such compounds are thiadiazole polysulfides having 5 to 50 carbon atoms, derivatives thereof and polymers thereof. Derivatives of 1,3,4-thiadiazole are common, such as those disclosed in US Pat. Nos. 2,719,125, 2,719,126 and 3,087,932. Other similar materials are described in U.S. Pat. Nos. 3,821,236, 3,904,537, 4,097,387, 4,107,059, 4,136,043, 4,188,299 and 4,193,882. Other additives are thiadiazole thio and polythiosulfenamides, such as those described in British Patent Specification 1,560,830. Benzotriazole derivatives are also included in this class of additives. When these compounds are included in the lubricant composition, they are preferably present in an amount not exceeding 0.2% by weight of the active ingredient.

A small amount of a demulsifier component may be used. A preferred demulsifier component is described in EP 330,522. It is obtained by reacting an alkylene oxide with an adduct obtained by reacting a bis-epoxide with a polyhydric alcohol. The demulsifier should be used in an amount not exceeding 0.1% by weight of the active ingredient. A treat rate of 0.001 to 0.05% by weight of active ingredient is convenient.
Pour point depressants, also known as lubricant improvers, lower the minimum temperature at which a liquid can flow or pour. Such additives are well known. Common additives that improve the low temperature fluidity of the liquid are C8 and C18 dialkyl fumarate / vinyl acetate copolymers, polyalkyl methacrylates, and the like.

Foam control can be provided by several compounds including anti-foaming agents of the polysiloxane type, such as silicone oil or polydimethylsiloxane.
When used in lubricating oil compositions, typical effective amounts of such additives are as follows:

^*最終潤滑油組成物をベースとした活性成分の質量％

^* Mass% of active ingredient based on final lubricating oil composition

The amount of nitrogen from the dispersant additive composition that is generally present in the additive concentrate is 0.33 to 0.47% by weight, for example 0.37 to 0.41% by weight, based on the weight of the additive concentrate.
The amount of soap from the detergent additive composition that is typically present in the additive concentrate is 103-145 millimoles, for example 116-125 millimoles per 1000 grams of concentrate.
Accordingly, a method for producing a lubricating oil composition according to the present invention comprises the steps of mixing a lubricating viscous oil and one or more additives or additive concentrates (including two or more additives), and then the desired Can include the step of mixing other additive components, such as viscosity modifiers, multifunctional viscosity modifiers, and pour point depressants.

Conveniently, the phosphorus and sulfur content of the lubricating oil composition is derived from additives in the lubricating oil composition, such as zinc dithiophosphate.
Lubricating oil compositions may be used by adding lubricating oil to machine engine components, specifically internal combustion, such as compression ignition, to lubricate the engine. As a specific example of a compression ignition engine, which has been developed in recent years, the specific power is increased to about 5 kW / liter or more, for example, 25 kW / liter or more, preferably at least 30 kW / liter, particularly 40 kW / liter or more. Therefore, the top ring groove temperature may exceed 150 ° C, and preferably may exceed 250 ° C. Preferably, the maximum specific output is about 60 kW / liter. These engines are more prone to ring stick problems during their operation.

  It will be appreciated that after two or more additives containing two or more detergents are placed in the oil composition, an interaction may occur between them. The interaction may occur either in the mixing process or in the subsequent conditions that the composition undergoes, including the use of the composition in the work environment. Interaction may also occur when supplemental additives are added to the composition or oil component of the present invention. Such interactions may include interactions that change the chemical constituents of the additive. Thus, the compositions of the present invention include, for example, compositions in which interaction between any of the additives occurs and compositions in which no interaction occurs, for example, between ingredients mixed in the oil.

In this specification,
As used herein, the term “hydrocarbyl” means that the group concerned is composed primarily of hydrogen and carbon atoms and is bonded to the rest of the molecule through the carbon atom, but the substantial hydrocarbon of that group. It does not exclude the presence of other atoms or groups in a ratio insufficient to impair the properties.
As used herein, the term “comprising” or “comprising” is used to identify the presence of a stated feature, integer, step or ingredient, but one or more of those other features, integer, step Does not exclude the presence or addition of ingredients or groups. As used herein, the term “comprising” or “comprising” is a preferred embodiment of the term “consisting essentially of” and its cognate language, while the term “consisting of” and its cognate language are termed “ Is a preferred embodiment of “consisting essentially of”.

As used herein, the term “oil-soluble” or “oil dispersible” does not mean that the additive is soluble, soluble, miscible or suspendable in all proportions to the oil. However, they indicate that the additives are soluble or stably dispersible in oil, for example, to the extent that they are effective in the environment in which they are used. means. Furthermore, further introduction of other additives, such as those described above, may affect the solubility or dispersibility of the additive.
“Major amount” means greater than 50% by weight of the composition, for example 70% by weight, preferably 75-97% by weight, in particular 80-95 or 90% by weight.
“Minor amount” means less than 50% by weight of the composition, for example less than 30% by weight, for example 3 to 25% by weight, preferably 5 or 10 to 20% by weight.

The term “molybdenum-sulfur compound” refers to a compound having one or more molybdenum atoms and at least one sulfur atom, preferably bonded to one or more molybdenum atoms, and one or more non-molybdenum atoms, such as carbon. A compound having at least one sulfur atom bonded to, more preferably at least one sulfur atom bonded only to one or more molybdenum atoms, such as the core [Mo ₂ S ₄ ], [Mo ₃ S ₄ ] and It means a compound represented by [Mo ₃ S ₇ ]. An atom selected from oxygen and selenium may replace one or more sulfur atoms in such a core. Conveniently, the core consists only of molybdenum and sulfur atoms. Thus, the term “molybdenum-sulfur additive” means an additive comprising one or more molybdenum-sulfur compounds.
All percentages stated are weight percentages based on active ingredient, unless otherwise specified, i.e. independent of carrier or diluent oil.
The abbreviation SAE stands for Automotive Engineers Association, which classifies lubricants by viscosity grade.
The invention will now be described specifically by way of example as follows:

  Lubricating oil compositions that meet SAE 5W-30 grade are manufactured by methods known in the art and engine tests used to study sediment formation (particularly the VWTDi CEC-L-78-T-99 test). Base and also known as PV1452 test). The test relates to industry standards and stringent assessments of lubricant work capacity.

  With the exception of the dispersant and detergent additive compositions, each lubricating oil composition contained the same additive in the same amount. Oils A, B, C, and 1 included borate and non-borate dispersant dispersant additive compositions, respectively, and oils C and 1 included higher amounts of non-borate dispersant. Oils A and C contained TBN168 calcium salicylate, while Oils B and 1 contained TBN168 calcium salicylate and TBN64 calcium salicylate detergent additive composition. The base stock used in each lubricating oil composition was a Group III base stock. The characteristics of the lubricating oil composition are shown in Table 1.

Test and results
The VWTDI test used a 4-cylinder, 1.9 liter, 81kW passenger car diesel engine. It was a direct injection engine and a turbocharger system was used to increase the output of the unit. Industrial test methods consist of repeated cycles of hot and cold operating conditions, so-called PK cycles. This includes a 30 minute idle period at zero load followed by a 180 minute full load and 4150 rpm. The entire cycle was then repeated for a total of 54 hours. During this 54 hour period, the initial oil charge of 4.5 liters of the test lubricant was not replenished.

  At the end of the 54 hour test, the engine was drained, the engine was disassembled, and the piston was evaluated for piston deposits and piston ring sticks. This gave results related to the industry reference oil (RL206) for defining pass or fail performance.

The piston was evaluated against what is known as a DIN evaluation system. The three piston ring grooves and the two piston lands between the grooves were evaluated on a merit scale for deposits and scored from 100 by methods known to those skilled in the art. In summary, the higher the number, the better the performance: 100 indicates completely clear and 0 indicates complete coverage with sediment. After that, the five scores were averaged and the overall piston cleanliness merit evaluation was shown. The scores for each of the four pistons were then averaged to give total piston cleanliness for the test.
The results are shown in Table 1 below.

The data in Table 1 shows that Oil B and Oil C, each having an increased soap content or dispersant content compared to Oil A, resulted in improved piston cleanliness. However, oil 1 with increased soap content and dispersant content showed a clear improvement in piston cleanliness compared to oils A, B and C. Therefore, the use of increased amounts of dispersants and detergents in lubricating oil compositions that give 1.0% by weight or less of sulfated ash was useful to achieve acceptable performance in the VWTDi engine test.

Claims (18)

  A lubricating oil composition produced by containing or mixing a large amount of lubricating oil and a small amount of (A) a dispersant additive composition and (B) a detergent additive composition, the oil composition Gives a sulfate ash content of 1.0 mass% or less, such as 0.3 to 0.9 mass%, preferably 0.5 to 0.7 mass%, and has a total base number (TBN) of 4 to 9.5, such as 5 to 9, preferably 6 to 8.5. Having at least 0.08% by weight of nitrogen from the additive composition, based on the weight of the oil composition, for example 0.085 to 0.115% by weight, preferably 0.09 to 0.10% by weight, and soap from the detergent additive composition, The above lubricating oil composition having at least 25 mmol, specifically at least 28 mmol, such as 35 mmol or less per 1000 g of oil composition.   The lubricating oil of claim 1 comprising a large amount of Group III base stock, preferably at least 20% by weight, for example at least 40% by weight, more preferably 45-90% by weight, based on the weight of the oil composition. The oil composition as described.   The oil composition according to claim 1 or 2, wherein the dispersant additive composition comprises a borate dispersant and a non-borate dispersant.   A soap according to any one of claims 1, 2 or 3, wherein 35 mmol% or less, for example 5-30 mmol%, preferably 10-25 mmol%, of the soap in the lubricating oil composition is derived from a detergent having a TBN higher than 150. Oil composition.   The detergent additive composition comprises at least one metal detergent based on one or more organic acids that do not contain sulfur, specifically at least one metal salicylate, preferably calcium salicylate, more preferably TBN. The oil composition according to any one of claims 1 to 4, comprising a calcium salicylate of 150 or less, such as 100 or less, preferably 80 or less.   The oil composition according to any one of claims 1 to 5, wherein the detergent additive composition comprises calcium salicylate having a TBN of 150 to 200 and calcium salicylate having a TBN of 80 or less.   The oil composition of any one of the preceding claims, further comprising one or more antioxidant compositions comprising an aromatic amine, a hindered phenol and a molybdenum compound.   The oil composition according to any one of claims 1 to 7, further comprising a zinc dialkyldithiophosphate comprising secondary alkyl groups in a majority molar ratio based on the amount of alkyl groups.   The sulfur content of the oil composition is 0.25% by weight or less, preferably 0.2% by weight or less, for example 0.05 to 0.15% by weight, based on the weight of the oil composition. Oil composition.   The phosphorus content of the oil composition is 0.09 wt% or less, such as 0.08 wt% or less, preferably 0.01 to 0.07 wt%, such as 0.03 to 0.06 wt%, based on the weight of the oil composition. The oil composition according to any one of the above.   11. The oil composition according to any one of claims 1 to 10, wherein the molybdenum content of the oil composition is 300 ppm or less, preferably 10 to 200 ppm, in particular 50 to 175 ppm, based on the mass of the oil composition.   The oil composition according to any one of claims 1 to 11, wherein the boron content in the oil composition is 150 ppm or less, preferably 10 to 100 ppm, in particular 25 to 75 ppm, based on the mass of the oil composition. .   13. The oil composition according to any one of claims 1 to 12, wherein the dispersant comprises polyisobutenyl succinimide made using high vinylidene polyisobutene.   A method of lubricating a compression ignition internal combustion engine comprising operating the engine and lubricating the engine with the lubricating oil composition of any one of claims 1-13.   A method for improving piston cleanliness and reducing ring-stick tendency of a compression ignition internal combustion engine comprising adding the lubricating oil composition of any one of claims 1-13 to the engine.   A combination comprising a compression ignition internal combustion engine, preferably a crankcase having a specific output of 25 kW / liter or more, and a lubricating oil composition according to any one of claims 1-13.   An internal combustion engine piston in an amount of (1) a dispersant additive composition that provides at least 0.085 wt% nitrogen and (2) an amount of detergent additive composition that provides at least 25 mmol soap per 1000 g of oil composition. Use in a lubricating oil composition for improving cleanliness, wherein the oil composition provides a sulfate ash content of 1.0 wt% or less and a TBN of 4 to 9.5.   10 or 13.5-30% by weight, preferably 16-27% by weight, for example 18-25% by weight, based on the weight of the oil composition (in the above additives the viscosity modifier and pour point depressant additive are Not included) in an amount that provides the lubricating oil composition of any one of claims 1 to 3 in a ratio that provides the lubricating oil composition of any one of claims 1-3. An additive concentrate for the production of a lubricating oil composition comprising the composition.