JP2008095101A - Lubricating oil with enhanced piston deposit controlling capability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To propose a lubricating composition exhibiting at least either one of enhanced piston deposit controlling capability and viscosity control, because the lubricating composition satisfying higher performance level as a new-generation engine requires is needed. <P>SOLUTION: The lubricating composition comprises a major amount of a base oil and a small amount of an additive composition containing an overbasic detergent and a low-base detergent, wherein the ratio of a salt to a metal which the lubricating composition has is within a range of about 3.0 to about 8.0. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present disclosure relates to lubricating compositions, methods of making and using the same. More particularly, the present disclosure relates to a lubricating composition comprising an overbased detergent and a low-base detergent.

  Lubricants suitable for use in modern engines need to meet industrial performance specifications such as ILSAC GF-4 and API SM. One of the requirements for ILSAC GF-4 and API SM is to pass the Sequence IIIG test. The Sequence IIIG test measures oil thickening and piston deposits during high temperature conditions. For a test oil to meet the minimum criteria for GF-4 / SM, it must have a maximum Sequence IIIG viscosity increase of 150% and a weighted piston deposit (WPD) of at least 3.5. However, certain OEMs require that their particular family of engines exhibit higher performance levels as defined by these internal specifications. For example, General Motors GM4718M requires a Sequence IIIG viscosity increase of up to 90% and a WPD of at least 5.5.

  Accordingly, there is a need for a lubricating composition that can satisfy higher performance levels as required by new generation engines. The present disclosure proposes a lubricating composition that may exhibit at least one of improved piston deposit control capability and viscosity control.

Summary In accordance with the present disclosure, a base oil and a minor amount of an additive composition comprising an overbased detergent and a low base detergent, wherein the salt to metal ratio is from about 3.0 to about 8 A lubricating composition that is in the range of 0.0 is disclosed.

  In accordance with another aspect of the present teachings, a method for improving piston cleanliness is taught, the method comprising adding a major amount of base oil to at least one piston and containing an overbased detergent and a low base detergent. Providing a lubricating composition comprising a minor amount of the agent composition, wherein the ratio of salt to metal ranges from about 3.0 to about 8.0.

  In accordance with yet another aspect of the present teachings, a method for passing a combustion system to the Sequence IIIG test is taught, the method comprising a major amount of base oil in the combustion system and containing an overbased detergent and a low base detergent. Providing a lubricating composition comprising a minor amount of the additive composition, wherein the salt to metal ratio ranges from about 3.0 to about 8.0.

  In accordance with another aspect of the present teachings, a method for dispensing lubricating oil to a moving part of a machine is taught, the method comprising at least one moving part containing a major amount of base oil and an overbased detergent and a low base detergent. Contacting with a lubricating composition comprising a minor amount of the additive composition, wherein the ratio of salt to metal ranges from about 3.0 to about 8.0.

  Additional advantages of the present disclosure will be set forth in part in the following description, or may be learned by practice of the disclosure. Such advantages can be realized and achieved using the elements and combinations particularly pointed out in the appended claims.

It is to be understood that both the general description provided above and the detailed description provided below are merely exemplary and explanatory and are not intended to limit the present disclosure as claimed.

DESCRIPTION OF EMBODIMENTS Although the numerical ranges and parameters representing the broad range of this disclosure are approximate, the numerical values given in the specific examples are reported as accurately as possible. Any numerical value, however, inherently contains certain errors, which are necessarily the result of standard deviation found in individual testing measurements. Moreover, the ranges disclosed herein are to be understood to encompass all and any sub-ranges that are all included therein. For example, a “less than 10” range may include all and any of the subranges between the lowest value of zero and the highest value of 10 (inclusive), ie, equal to zero. All or any of a small range having a minimum value greater than that and a maximum value equal to or less than 10 may be included, such as a range of 1 to 5, for example.

  The lubricating composition of the present disclosure may comprise a major amount of base oil and a small amount of an additive composition comprising an overbased detergent and a low base detergent, wherein the lubricating composition The salt to metal ratio is in the range of about 3.0 to about 8.0. The term “major amount” as used herein is understood to mean an amount equal to or greater than 50% by weight, such as from about 80 to about 98% by weight, based on the total weight of the lubricating composition. . Moreover, the term “small amount” as used herein is understood to mean an amount of less than 50% by weight, based on the total weight of the lubricating composition.

  The disclosed lubricating and additive compositions are used in a variety of applications, such as spark ignition and compression ignition internal combustion engines (automobile and truck engines, two-cycle engines, aviation piston engines, marine engines and low-load diesel engines, rotary engines, For example, a crankcase lubricating composition for a hybrid engine).

  Base oils suitable for use in formulating the disclosed compositions can be selected from either synthetic or mineral oils or mixtures thereof. Mineral oils include animal and vegetable oils (eg, castor oil, lard oil) as well as other lubricating mineral oils such as liquid petroleum and solvent treated or acid treated paraffinic, naphthenic or paraffinic-naphthenic mixed types Of mineral oil for lubrication. Oils derived from coal or shale are also suitable. Furthermore, oils obtained by a gas-to-liquid process are also suitable.

  The viscosity of such base oils at 100 ° C. can typically be, for example, from about 2 to about 15 cSt, and as a further example, from about 2 to about 10 cSt. Accordingly, the viscosity of such base oils can usually range from about SAE 50 to about SAE 250, and more usually from about SAE 70W to about SAE 140. Suitable automotive oils also include cross grades such as 75W-140, 80W-90, 85W-140, 85W-90 and the like.

  Non-limiting examples of synthetic oils include hydrocarbon oils such as olefin polymers and copolymers (eg polybutylene, polypropylene, propylene and isobutylene copolymers); polyalphaolefins [eg poly (1-hexene), Poly- (1-octene), poly (1-decene) and the like and mixtures thereof]; alkylbenzene [eg, dodecylbenzene, tetradecylbenzene, di-nonylbenzene, di- (2-ethylhexyl) benzene, etc.]; polyphenyl ( For example, biphenyl, terphenyl, alkyl-substituted polyphenyl, etc.); alkyl-substituted diphenyl ethers and alkyl-substituted diphenyl sulfides, and derivatives, analogs and homologues thereof.

They constitute another class of known synthetic oils in which alkylene oxide polymers and copolymers and derivatives whose terminal hydroxyl groups have been modified by esterification, etherification, etc. can be used. Examples of such oils include oils made by polymerization of ethylene oxide or propylene oxide, alkyl and aryl ethers of such polyoxyalkylene polymers (eg, methyl-polyisopropylene glycol ether having an average molecular weight of about 1000, Diphenyl ether of polyethylene glycol having a molecular weight of about 500-1000, diethyl ether of polypropylene glycol having a molecular weight of about 1000-1500, etc.) or their mono- and polycarboxylic acid esters, for example acetate of tetraethylene glycol, mixed C _3-8 It may be a fatty acid ester or a C ₁₃ oxo acid diester.

  Other types of synthetic oils that can be used include dicarboxylic acids (eg phthalic acid, succinic acid, alkyl succinic acid, alkenyl succinic acid, maleic acid, azelaic acid, suberic acid, sebacic acid, fumaric acid, adipic acid, linoleic acid. Esters of dimers, malonic acid, alkylmalonic acid, alkenylmalonic acid, etc.) and various alcohols (eg butyl alcohol, hexyl alcohol, dodecyl alcohol, 2-ethylhexyl alcohol, ethylene glycol, diethylene glycol monoether, propylene glycol, etc.) included. Specific examples of such esters include dibutyl adipate, di (2-ethylhexyl) sebacate, di-n-hexyl fumarate, dioctyl sebacate, diisooctyl azelate, diisodecyl azelate, dioctyl phthalate, didecyl phthalate And dieicosyl sebacate, 2-ethylhexyl diester of linoleic acid dimer, complex ester formed by reacting 1 mol of sebacic acid, 2 mol of tetraethylene glycol and 2 mol of octylic acid, and the like.

Also useful esters for use as synthetic oils were made from C _5-12 monocarboxylic acids and polyols and polyol ethers such as neopentyl glycol, trimethylolpropane, pentaerythritol, dipentaerythritol, tripentaerythritol, etc. Esters are also included.

  Accordingly, the base oils that can be used in making the compositions as described herein can be selected from any of the base oils in Group IV as specified by the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. It is. Such base oil groups are as follows:

  Group I has a saturate content of less than 90% and / or a sulfur content greater than 0.03% and a viscosity index equal to or greater than 80 and less than 120, Group II has a saturate content The amount is equal to or greater than 90% and the sulfur content is equal to or less than 0.03% and the viscosity index is equal to or greater than 80 and less than 120; III has a saturate content equal to or greater than 90% and a sulfur content equal to or less than 0.03% and a viscosity index equal to or greater than 120 Group IV is a polyalphaolefin (PAO), and other base stocks that do not enter Group V, Group I, II, III, or IV Parts are included.

  The test method used in the group limitation is one of ASTM D2007 for saturates, ASTM D2270 for viscosity index, and ASTM D2622, 4294, 4927 and 3120 for sulfur.

Group IV base stocks, or polyalphaolefins (PAOs), include hydrogenated alpha-olefin oligomers, the most important methods of oligomerization being free radical methods, Ziegler catalysis, and cationic, free It is a Del Crafts catalytic reaction.

  The viscosity of such polyalphaolefins at 100 ° C is typically in the range of about 2 to about 100 cSt, such as about 4 to about 8 cSt at 100 ° C. They may be, for example, branched or linear alpha-olefin oligomers having from about 2 to about 30 carbon atoms, including, but not limited to, polypropene, polyisobutene, poly-1-butene, poly-1- Hexene, poly-1-octene and poly-1-decene are included. Homopolymers, copolymers and mixtures are included.

  With respect to the balance of base stocks shown above, “Group I base stock” also includes Group I base stocks that may be mixed with one or more base stocks of one or more other groups. Are included, provided that the resulting mixture has characteristics within the specified characteristics for the Group I basestock.

  Typical base stocks include Group I base stocks and mixtures of Group II bases and Group I base stocks.

  Base stocks suitable for use herein can be produced using a wide variety of methods including, but not limited to, distillation, solvent purification, hydroprocessing, oligomerization, Esterification and repurification are included.

Such base oils may be oils derived from Fischer-Tropsch synthetic hydrocarbons. Fischer-Tropsch synthesized hydrocarbons can be produced from synthesis gas containing H ₂ and CO using a Fischer-Tropsch catalyst. Such hydrocarbons typically require further processing in order to make it useful as a base oil. For example, such hydrocarbons may be hydroisomerized using the methods disclosed in US Pat. No. 6,103,099 or 6,180,575, or US Pat. It may be hydrocracked and hydroisomerized using the methods disclosed in US Pat. No. 4,943,672 or 6,096,940 or disclosed in US Pat. No. 5,882,505. May be dewaxed using the methods described, or use the methods disclosed in US Pat. Nos. 6,013,171, 6,080,301 or 6,165,949. Hydroisomerization and dewaxing may be performed.

  Unrefined, refined, and rerefined oils of the type of mineral or synthetic oil disclosed above (as well as mixtures of any two or more thereof) can be used as the base oil. Unrefined oils are oils obtained directly from mineral oils or synthetic sources without further purification. For example, shale oil obtained directly from retort harvesting operations, petroleum oil obtained directly from primary distillation, or ester oil obtained directly from the esterification process (used without further treatment) would be unrefined oil. Refined oils are similar to unrefined oils except that they have undergone further processing in one or more purification stages to improve one or more properties. Many such purification techniques are known to those skilled in the art, such as solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, and the like. The re-refined oil is an oil obtained by applying a treatment similar to the treatment used for obtaining a refined oil to a refined oil that has already been used in practice. Such rerefined oils are also known as reclaimed or reprocessed oils, and often they undergo additional processing using techniques aimed at removing spent additives, contaminants and oil breakdown products. ing.

  A detergent may be present in the disclosed composition for the purpose of keeping the insoluble material in suspension, thereby preventing its deposition which may be harmful. The cleaning agent also has the ability to redisperse deposits that have already occurred. Detergents can typically have the property of neutralizing acids. The lubricating and additive compositions disclosed herein can comprise at least one detergent. In one aspect, the lubricating and additive composition may contain at least two detergents, one of which may be an overbased detergent and the other is a low base detergent. There may be.

  The cleaning agent used in the present specification may be any cleaning agent. Non-limiting examples of detergents include sulfonates such as metals, especially alkali or alkaline earth metals such as barium, sodium, potassium, lithium, calcium and magnesium, phenates, sulfide phenates, carboxylates, salicylates, thiophosphones. Acid salts, naphthenic acid salts, and combinations thereof.

  Such detergents may generally contain a long hydrophobic tail in addition to the polar head, said polar head comprising a metal salt of an organic acid. Such salts may comprise a substantial stoichiometric amount of the metal. The total base number (TBN) exhibited by a cleaning agent is the amount of acid necessary to neutralize all of the alkalinity exhibited by the material and can be measured according to ASTM D 2896. As an example, the preparation of an overbased cleaning material having a TBN of 150 or more may comprise a mixture comprising an acidic organic compound and a stoichiometric excess of a metal base and an acidic material (typically an inorganic or lower carboxylic acid, For example, carbon dioxide can be reacted.

  The low base detergent that can be used in the disclosed lubricating compositions can have a TBN of about 150 or less, such as less than about 80, as a further example, less than 50, and as another example, less than about 30.

  The amount of such low base detergent present in the lubricating compositions disclosed herein can be any necessary or effective amount. In one aspect, such a low base detergent is present in the lubricating composition from about 0.1 wt% to about 3.5 wt%, such as about 0.5 wt%, based on the total weight percent of the lubricating composition. % To about 3% by weight, and as a further example, it may be present in an amount ranging from about 1.0% to about 3% by weight. The metal content of such low base detergents is from about 0.005% to about 0.175% by weight, for example from about 0.025% to about 0.00%, based on the total weight percent of the low base detergent. It may range from 15% by weight, further examples from about 0.075% to about 0.15% by weight.

  An overbased detergent suitable for use in the disclosed lubricating composition may have a TBN of about 150 or greater, such as about 250 or greater, and as a further example about 400 or greater. The TBN in one aspect can range from about 150 to about 500.

  The amount of such overbased detergent present in the lubricating compositions disclosed herein can be any necessary or effective amount. In one aspect, such overbased detergent is from about 0.5% to about 3.5%, such as from about 1% to about 2.5% by weight, based on the total weight of the lubricating composition. May be present in amounts ranging from. The metal content of such overbased detergent is from about 0.05% to about 0.7%, such as from about 0.1% to about 0.00%, based on the total weight percent of the overbased detergent. It may be in the range of 5% by weight.

  In various aspects, the weight ratio of low base detergent to overbased detergent in the disclosed lubricating composition is from about 0.1 to about 7, for example from about 0.2 to about 5, further examples being about 0.5. To about 2.5.

  In some aspects, the ratio of salt to metal in the disclosed lubricating composition is from about 3.0 to about 8.0, such as from about 3.5 to about 7.5, as a further example about 4.0. To about 6.5.

  Non-limiting examples of suitable metal-containing detergents include, but are not limited to, lithium phenate, sodium phenate, potassium phenate, calcium phenate, magnesium phenate, barium phenate, lithium sulfide phenate, Barium sulfide phenate, sodium sulfide phenate, potassium sulfide phenate, calcium sulfide phenate and magnesium sulfide phenate (each aromatic group has one or more fatty groups to show hydrocarbon solubility), lithium sulfonate, Barium sulfonate, sodium sulfonate, potassium sulfonate, calcium sulfonate and magnesium sulfonate (each sulfonic acid moiety is bound to an aromatic nucleus, which is usually a fatty substituent so as to exhibit hydrocarbon solubility. 1 or more), Salichi Lithium acid, barium salicylate, sodium salicylate, potassium salicylate, calcium salicylate and magnesium salicylate (the aromatic moiety is generally substituted with one or more fatty substituents to show hydrocarbon solubility), from 10 carbon atoms Lithium, sodium, barium, phosphosulfurized hydrolyzate of 2,000 olefins or hydrolysates of phosphide hydrolysates of alcohols and / or fatty substituted phenolic compounds having 10 to 2,000 carbon atoms, Potassium, calcium and magnesium salts, lithium, sodium, barium, potassium, calcium and magnesium salts of aliphatic carboxylic acids and fatty substituted alicyclic carboxylic acids, and similar alkali salts of various other oil-soluble organic acids. Salts and overbased salts of such substances slightly alkaline earth metal salts include. It is also possible to use a mixture of two or more different alkali and / or alkaline earth metal overbase salts. It is also possible to use an overbased salt of two or more different acids or a mixture of two or more acids of different types (for example, one or more overbased calcium phenates and one or more overbased calcium sulfonates). Is possible.

  Methods for producing overbased detergents containing alkali and alkaline earth metals are well known to those skilled in the art and have been extensively reported in the patent literature. US Pat. Nos. 2,451,345; 2,451,346; 2,485,861; 2,501,731; 2,501,732; 2,585,520; 2,671,758; 904; 2,616,905; 2,616,911; 2,616,924; 2,616,925; 2,617,049; 2,695,910; 3,178,368; 3,367,867; 3,488,284; 3,496,105; 3,629,109; 3,779,920; 3,865,737; 3,907,691; 4,100,085; 129,589; 4,137,184; 4,148,740; 4,212,752; 4,394,277; 4,563,293; 4,617,135; 4,647,387; 4,880 550; 5,075,383; 5,139,688; 5,238,588; 5,652,201; 6,107,257; 6,444,625; 6,869,919; and 6,423,670 No .; British Patent Application No. 2,082,619A and European Patent Application Publication Nos. 121,024 B1 and 259,974 A2 (the disclosures of which are incorporated herein by reference).

  The lubricating compositions of the present disclosure can also be mixed, for example, as described in US Pat. Nos. 6,153,565; 6,281,179; 6,429,178; 6,429,179; and 6,869,919. "Hybrid" detergents generated using surfactant systems such as phenate / salicylate, sulfonate / phenate, sulfonate / salicylate, sulfonate / phenate / salicylate, etc. can also be included It is.

Another type of detergent that can be used in the lubricating compositions of the present disclosure includes US Pat. No. 6,482,77.
Includes zinc-containing detergents such as those disclosed in No. 8 (incorporated herein by reference) such as zinc sulfonate, zinc carboxylate, zinc salicylate, zinc phenate and zinc sulfide phenate and mixtures thereof It is. An overbased zinc-containing detergent can be produced by reacting a neutral zinc-containing detergent with a metal hydroxide. This reaction can typically occur with carbon dioxide in the presence of an accelerator, which is generally an alcohol type material. The promoter dissolves a small amount of metal hydroxide, which later reacts with carbon dioxide to form a metal carbonate. The amount of metal carbonate incorporated into the overbased detergent can vary depending on the application for which the overbased detergent is used. Zinc sulfonate can also be used in the lubricating compositions of the present disclosure, including but not limited to, for example, zinc dihydrocarbyl aromatic sulfonates such as zinc dialkylnaphthalene sulfonates. The sulfonate group of the zinc dialkylnaphthalene sulfonate is attached to one ring in the naphthalene nucleus and the alkyl group is attached to each ring. Each alkyl group may independently contain from about 6 to about 20 carbon atoms, and they may contain from about 8 to 12 carbon atoms. The dialkylnaphthalene sulfonate group is bonded to zinc through the sulfonate group.

  The lubricating composition may further contain other optional additives such as dispersants, antiwear agents, antioxidants, antifoaming agents, diluents, friction modifiers, viscosity index improvers, pour point depressants, etc. Is also possible. Such optional additives may be present in any effective amount necessary so long as they do not interfere with the cleaning agents disclosed herein.

  In accordance with various aspects, a method for improving piston cleanliness is disclosed. As used herein, the term “improves piston cleanliness” increases piston cleanliness, eg, reduces the amount of deposits on the piston as compared to pistons that do not use the lubricating composition disclosed herein. I understand that it means. A method for improving piston cleanliness comprises a base oil in at least one piston and a small amount of an additive composition comprising an overbased detergent and a low base detergent, and a salt for metal. Providing a lubricating composition having a ratio of about 3.0 to about 8.0.

  In another aspect, a method for passing a combustion system to the Sequence IIIG test is disclosed. This method includes a major amount of base oil in the combustion system and a small amount of an additive composition comprising an overbased detergent and a low base detergent, wherein the ratio of salt to metal is from about 3.0 to about Providing a lubricating composition that is in the range of 8.0.

  The “combustion system” shown in the present specification is, for example, but not limited to, a diesel-electric hybrid vehicle, a gasoline-electric hybrid vehicle, a two-cycle engine, a burner or a combustion device and all { For example, but not limited to, stationary burners (house heating, industrial, boilers, furnaces), waste incinerators, diesel fuel burners, diesel fuel engines [unit injected and common rail], It includes jet engines, HCCI engines, automotive diesel engines, gasoline fuel burners, gasoline fuel engines (PFI and DIG), power plant generators, etc.}. Hydrocarbon fuel combustion systems that may benefit from the present disclosure include any combustion apparatus, system, device, and / or engine that combusts fuel. The “combustion system” referred to herein also includes internal combustion and external combustion devices, machines, engines, turbine engines, jet engines, boilers, incinerators that can burn or burn hydrocarbon-based fuels, It also means any and all of evaporative burners, plasma burner systems, plasma arcs, fixed burners and the like.

In accordance with various aspects, a method for dispensing lubricating oil to a moving part of a machine is disclosed, the method comprising at least one moving part comprising a major amount of base oil and an overbased detergent and a low base detergent. Contacting with a lubricating composition comprising a minor amount of the additive composition and having a salt to metal ratio ranging from about 3.0 to about 8.0. In some aspects, the machine in the method of dispensing lubricant to the moving part may be selected from the group consisting of spark ignition and compression ignition internal combustion engines, including automobile and truck engines, gas engines, diesel engines, Includes turbine engines, aviation piston engines, marine engines, rotary engines and hybrid engines.

  Three different lubricating compositions as shown in Table 1 were prepared: A, B and C. The A and B formulations used a similar dispersant / cleaner inhibitor (DI) system, but different mixtures of base fluids. The base fluids used in the B and C formulations were similar but differed in the ratio of overbased detergent to low base detergent.

  Table 2 shows the elemental analysis of the three types of formulations.

  By subjecting the three types of formulations A, B and C as described in Table 1 to the Sequence IIIG test, oil density and high temperature piston deposits are measured and valve mechanism wear information is provided. Obtained. Table 3 shows the results of the Sequence IIIG test.

  As can be seen from Table 3, A and B passed the Sequence IIIG requirement for GF-4 / SM, but did not pass the more stringent WPD performance for GM4718M (WPD minimum of 5.5) . Moreover, it should be noted that the performance shown by C for WPD is better than that shown by B. B and C were prepared using essentially the same base fluid mixture, but because of the different ratio of overbased detergent to low base detergent, C showed better performance. This may be due to the difference in the mixture of agent and low base detergent. Table 2 also shows the elemental analysis of A, B and C, which are the three types of preparations. It should be noted that the ratio of salt to metal that A and B have is the same, but that C has a higher value.

  At numerous places throughout this specification, reference has been made to a number of US patents, published foreign patent applications and published technical papers. All such presented materials are expressly incorporated into this disclosure as if set forth in detail herein.

For purposes of this specification and the appended claims, unless otherwise stated, numerical values representing amounts, percentages, or ratios and other numerical values used in this specification and claims are subject to the term “about” modification in all cases. Should be understood. Accordingly, unless indicated to the contrary, the numerical parameters set forth in this specification and the appended claims are approximations that may vary depending upon the desired properties sought to be obtained with this disclosure. At a minimum, each numerical parameter is interpreted by applying the usual rounding technique in the light of the number of significant figures reported, rather than as an attempt to limit the application of the equivalent principle applied to the scope of the claims. It should be.

  It should be noted that the singular forms “a”, “an” and “the” as used herein and in the appended claims encompass a plurality of indicating objects unless clearly and clearly limited to one indicating object. Thus, for example, reference to “an antioxidant” includes one or more different antioxidants. The term “inclusion” as used herein and grammatical variations thereof are not intended to be limiting, and enumerating items in a list may be used in place of or in addition to the listed items. It does not exclude other similar items that can be.

  The present invention is susceptible to considerable variations in this implementation. Accordingly, the above description is not intended and should not be construed as limiting the invention to the particular examples shown above. Rather, what is intended to be protected is the matter as set forth in the claims and their equivalents as permitted by law.

  Applicants do not intend to dedicate all disclosed aspects to the public, and any of the disclosed modifications or variations may not literally fall within the scope of the claims, but that To the extent they are also considered part of this invention under the principle of equivalents.

Claims (20)

A lubricating composition comprising:
A minor amount of an additive composition comprising a major amount of base oil, and an overbased detergent and a low base detergent,
A lubricating composition comprising, wherein the ratio of salt to metal ranges from about 3.0 to about 8.0.   The overbased detergent and the low base detergent are selected from the group consisting of metal sulfonates, phenates, sulfurized phenates, carboxylates, salicylates, thiophosphonates, naphthenates and combinations thereof. The lubricating composition described.   The lubricating composition of claim 1, wherein the overbased detergent is present in an amount ranging from about 0.5 wt% to about 3.5 wt%, based on the total weight of the composition.   The lubricating composition of claim 1, wherein the overbased detergent has a total base number of about 150 or greater.   The lubricating composition of claim 4, wherein the overbased detergent has a total base number of about 250 or greater.   The lubricating composition of claim 1, wherein the metal content of the overbased detergent is in the range of about 0.05 wt% to about 0.7 wt%.   The lubricating composition of claim 6, wherein the metal content of the overbased detergent ranges from about 0.1 wt% to about 0.5 wt%.   The lubricating composition of claim 1, wherein the weight ratio of low base detergent to overbased detergent is in the range of about 0.1 to about 7.   The lubricating composition of claim 1, wherein the low base detergent is present in an amount ranging from about 0.1 wt% to about 3.5 wt%, based on the total weight of the composition.   The lubricating composition of claim 1, wherein the low base detergent has a total base number of about 150 or less.   The lubricating composition of claim 10, wherein the low base detergent has a total base number of less than about 80.   The lubricating composition of claim 1, wherein the metal content of the low base detergent ranges from about 0.005 wt% to about 0.175 wt%.   The lubricating composition of claim 6, wherein the metal content of the low base detergent ranges from about 0.025 wt% to about 0.15 wt%.   The lubricating composition of claim 1, wherein the ratio of salt to metal ranges from about 3.5 to about 7.5.   The lubricating composition of claim 1, wherein the ratio of salt to metal ranges from about 4.0 to about 6.5.   Furthermore, it contains at least one additive selected from the group consisting of dispersants, antiwear agents, antioxidants, friction modifiers, antifoaming agents, diluents, pour point depressants and viscosity index improvers. The lubricating composition according to claim 1.   A method for improving piston cleanliness, comprising at least one piston containing a major amount of a base oil and a small amount of an additive composition comprising an overbased detergent and a low base detergent. Providing a lubricating composition wherein the ratio of salt to salt is in the range of about 3.0 to about 8.0.   A method for passing a combustion system to the Sequence IIIG test, wherein the combustion system comprises a major amount of base oil and a small amount of an additive composition comprising an overbased detergent and a low base detergent. Providing a lubricating composition wherein the ratio of salt to metal ranges from about 3.0 to about 8.0.   A method of inserting lubricating oil into a moving part of a machine, comprising at least one moving part containing a major amount of a base oil and a small amount of an additive composition comprising an overbased detergent and a low base detergent. Contacting with a lubricating composition comprising a salt to metal ratio ranging from about 3.0 to about 8.0.   20. The method of claim 19, wherein the machine is selected from the group consisting of spark ignition and compression ignition internal combustion engines.