JP7697884B2 - Lubricating compositions for diesel particulate filter performance - Google Patents

Description

The present disclosure relates to lubricant compositions that exhibit reduced clogging in diesel engine particulate filters.

Passenger cars and light vehicles may be equipped with either compression (diesel) or spark-ignition (gasoline) internal combustion engines. Generally, engine oils are specially formulated for use in one or the other. However, it may be beneficial to lubricate a spark-ignition engine with an engine oil formulated for a compression engine. In addition, some diesel engine oils have been tested to meet the specifications for both diesel and gasoline engine oils (i.e., blend specifications) and are therefore recommended for use in either engine type. Thus, an oil that can meet the specifications for both diesel and gasoline engines and accommodate each of these diverse engine conditions is desirable.

Vehicles with compression ignition engines are often equipped with diesel particulate filters. Such filters can become clogged with particulate matter, which is caused by the deleterious effects of ash, sulfur, and phosphorus. Reducing the levels of phosphorus and sulfur can be achieved, for example, by reducing the amount of zinc dithiophosphate and using low sulfur base oils.

The primary sources of ash in lubricating oil compositions are generally metal detergents and zinc dithiophosphate anti-wear additives used internally. To reduce clogging in diesel particulate filters, current methods involve reducing the presence of detergents. However, reducing the amount of detergent has a detrimental effect on the basicity of the lubricating oil composition, which is essential for neutralizing the acidic by-products of combustion/oxidation. It is therefore desirable to reduce the detrimental effect of ash on diesel particulate filters without compromising the basicity of the lubricating oil composition by reducing the amount of detergent.

Boost, spark-ignition internal combustion engines, such as turbocharged or supercharged internal combustion engines, can exhibit an abnormal combustion phenomenon known as stochastic pre-ignition or low-speed pre-ignition (or "LSPI"). LSPI is a pre-ignition event that can include extreme high pressure spikes, early combustion during improper crank angles, and knock. All of these, individually and in combination, have the potential to cause engine degradation and/or serious damage.

Pre-ignition is a form of combustion that results from ignition of the air-fuel mixture in the combustion chamber prior to the desired ignition of the air-fuel mixture by the igniter. Pre-ignition is typically a problem during high speed engine operation because heat from engine operation can heat parts of the combustion chamber to a temperature sufficient to ignite the air-fuel mixture upon contact. This type of pre-ignition is sometimes referred to as hot spot pre-ignition.

More recently, intermittent abnormal combustion has been observed in boosted internal combustion engines at low speeds and medium to high loads. For example, low speed pre-ignition (LSPI) may occur in a random and stochastic manner during engine operation at or below 3000 rpm under load with a brake mean effective pressure (BMEP) of at least 1,000 kPa. During low speed engine operation, the compression stroke time is longest.

U.S. Patent Application Publication No. 2007/0129266 A1 relates to a lubricating oil composition comprising a base oil and one or more magnesium detergents for reducing clogging in diesel particulate filters.

U.S. Patent Application Publication No. 2003/182847A1 relates to a fuel additive, a lubricating oil additive for diesel engines having a diesel particulate filter, comprising a molybdenum compound having a measured sulfated ash content of 1.0 wt.% or less, a sulfur content of 0.3 wt.% or less, and a molybdenum content of 100 ppm or more.

The present disclosure relates to a lubricating oil composition comprising a calcium-containing detergent and a magnesium-containing detergent, and a method for reducing clogging in a diesel particulate filter comprising operating an engine equipped with a diesel particulate filter and lubricated with the lubricating oil composition comprising the calcium-containing detergent and the magnesium-containing detergent.

In a first aspect, the present disclosure relates to a lubricating oil composition comprising one or more calcium-containing detergents and one or more magnesium-containing detergents. The lubricating oil composition of the present disclosure comprises greater than 50 wt. % of a base oil of lubricating viscosity, an amount of one or more calcium-containing detergents to provide less than 1700 ppm of calcium, an amount of one or more magnesium-containing detergents to provide less than 450 ppm of magnesium, an amount of one or more molybdenum-containing compounds to provide less than 450 ppm of molybdenum, from about 700 ppm to about 900 ppm of phosphorus, a total measured sulfated ash content of 1.0 wt. % or less, and a ratio in ppm of calcium from the one or more calcium-containing detergents to magnesium from the one or more magnesium-containing detergents of 1:1 or greater, all based on the total weight of the lubricating oil composition.

In the aforementioned embodiments, the lubricating oil composition may provide a diesel particulate filter delta pressure (ΔP) versus oil consumption result of 0.6 kPa/kg or less, 0.5 kPa/kg or less, or 0.45 kPa/kg or less after 144 hours, as measured by the VW PV 1485 test.

In each of the foregoing embodiments, the lubricating oil composition may be effective to reduce low speed pre-ignition events in a boosted internal combustion engine lubricated with the lubricating oil composition relative to several low speed pre-ignition events in the same engine lubricated with reference lubricant R-1, or the reduction in LSPI events may be a 50% or greater reduction, where the LSPI events are LSPI counts during 25,000 engine cycles and the engine is operated at 2000 revolutions per minute with a brake mean effective pressure of 1,800 kPa.

In each of the foregoing embodiments, the one or more magnesium-containing detergents may provide 440 ppm or less of magnesium, or 430 ppm or less of magnesium, or 420 ppm or less of magnesium, or 410 ppm or less of magnesium, based on the total weight of the lubricating oil composition.

In each of the foregoing embodiments, the ratio, in ppm, of total calcium from the one or more calcium-containing detergents to total magnesium from the one or more magnesium-containing detergents may be greater than 2.0, or greater than 2.5, or greater than 3.0, or greater than 3.5, or less than 10.0, or less than 9.0, or less than 8.5, or greater than 1.0 to less than 10.0.

In each of the foregoing embodiments, the one or more calcium-containing detergents may be overbased having a total base number of greater than 200 mg KOH/g, or greater than 225 mg KOH/g or greater than 250 mg KOH/g, as measured by the method of ASTM D-2896.

In each of the foregoing embodiments, the one or more calcium-containing detergents may be present in an amount sufficient to provide less than 1670 ppm calcium, or less than 1500 ppm calcium, or less than 1400 ppm calcium, or greater than 1350 ppm to less than 1700 ppm calcium, based on the total weight of the lubricating oil composition.

In each of the foregoing embodiments, the total measured sulfate ash content may be less than 0.8 wt.%, or greater than 0.6 wt.% to less than 1.0 wt.%, or greater than 0.6 wt.% to less than 0.8 wt.%, each as measured by ASTM D874.

In each of the foregoing embodiments, the lubricating oil composition may provide an amount of one or more calcium-containing detergents having a total base number of up to 175 mg KOH/g as measured by the method of ASTM D-2896, and, when present, provides less than 50 ppm calcium, or less than 20 ppm calcium, or less than 5 ppm calcium, or about 0 ppm calcium, based on the total weight of the lubricating oil composition.

In each of the foregoing embodiments, the lubricating oil composition may contain less than 100 ppm boron, or less than 75 ppm boron, or less than 50 ppm boron, or less than 10 ppm boron, or about 0 ppm boron, based on the total weight of the lubricating oil composition.

In each of the foregoing embodiments, the lubricating oil composition may have greater than 0 ppm boron and a ratio of total metals in ppm to total boron in ppm greater than 7.5, or greater than 50, or greater than 75.

In each of the foregoing embodiments, the lubricating oil composition may contain from 0 ppm to less than 100 ppm of boron, or from 0 ppm to less than 75 ppm of boron, or from 0 ppm to less than 50 ppm of boron, or from 0 ppm to less than 10 ppm of boron.

In each of the foregoing embodiments, the one or more magnesium-containing detergents may be overbased having a total base number, as measured by the method of ASTM D-2896, of greater than 225 mg KOH/g, or greater than 250 mg KOH/g, or greater than 300 mg KOH/g, or greater than 350 mg KOH/g, or greater than 400 mg KOH/g.

In each of the foregoing embodiments, the one or more calcium-containing detergents may, optionally, exclude a calcium salicylate detergent.

In each of the foregoing embodiments, the one or more magnesium-containing detergents may be overbased magnesium sulfonates having a total base number, as measured by the method of ASTM D-2896, of greater than 225 mg KOH/g, or greater than 250 mg KOH/g, or greater than 300 mg KOH/g, or greater than 350 mg KOH/g, or greater than 400 mg KOH/g.

In each of the foregoing embodiments, the lubricating composition may be an engine oil composition.

In a second aspect, the disclosure relates to a method for reducing clogging in a diesel particulate filter comprising operating an engine equipped with a diesel particulate filter and lubricated with a lubricating oil composition comprising greater than 50 wt. % of a base oil of lubricating viscosity, an amount of one or more calcium-containing detergents to provide less than 1700 ppm of calcium, an amount of one or more magnesium-containing detergents to provide less than 450 ppm of magnesium, an amount of one or more molybdenum-containing compounds to provide less than 450 ppm of molybdenum, from about 700 ppm to about 900 ppm of phosphorus, a total measured sulfated ash content of 1.0 wt. % or less, and a ratio, in ppm, of calcium from the one or more calcium-containing detergents to magnesium from the one or more magnesium-containing detergents of 1:1 or greater, all based on the total weight of the lubricating oil composition as measured by ASTM D874.

In this second embodiment, the lubricating oil composition may provide a diesel particulate filter delta pressure (ΔP) versus oil consumption result of 0.6 kPa/kg or less, 0.5 kPa/kg or less, or 0.45 kPa/kg or less after 144 hours, as measured by the VW PV 1485 test.

In each of the second embodiments described above, the lubricating oil composition may be effective to reduce low speed pre-ignition events in a boosted internal combustion engine lubricated with the lubricating oil composition relative to several low speed pre-ignition events in the same engine lubricated with reference lubricant R-1, or the reduction in LSPI events may be a 50% or greater reduction, the LSPI events being an LSPI count during 25,000 engine cycles, the engine operating at 2000 revolutions per minute with a brake mean effective pressure of 1,800 kPa.

In each of the second embodiments described above, the one or more magnesium-containing detergents may provide 440 ppm or less of magnesium, or 430 ppm or less of magnesium, or 420 ppm or less of magnesium, or 410 ppm or less of magnesium, based on the total weight of the lubricating oil composition.

In each of the second embodiments described above, the ratio, in ppm, of total calcium from the one or more calcium-containing detergents to total magnesium from the one or more magnesium-containing detergents may be greater than 2.0, or greater than 2.5, or greater than 3.0, or greater than 3.5, or less than 10.0, or less than 9.0, or less than 8.5, or greater than 1.0 to less than 10.0.

In each of the second embodiments described above, the one or more calcium-containing detergents may be overbased having a total base number of greater than 200 mg KOH/g, or greater than 225 mg KOH/g or greater than 250 mg KOH/g, as measured by the method of ASTM D-2896.

In each of the second embodiments described above, the one or more calcium-containing detergents may be present in an amount sufficient to provide less than 1670 ppm calcium, or less than 1500 ppm calcium, or less than 1400 ppm calcium, or greater than 1350 ppm to less than 1700 ppm calcium, based on the total weight of the lubricating oil composition.

In each of the second embodiments described above, the total measured sulfate ash content may be less than 0.8 wt.%, or greater than 0.6 wt.% to less than 1.0 wt.%, each as measured by ASTM D874.

In each of the second embodiments described above, the lubricating oil composition may provide an amount of one or more calcium-containing detergents having a total base number of up to 175 mg KOH/g as measured by the method of ASTM D-2896, and, when present, provide less than 50 ppm calcium, or less than 20 ppm calcium, or less than 5 ppm calcium, or about 0 ppm calcium, based on the total weight of the lubricating oil composition.

In each of the second embodiments described above, the lubricating oil composition may contain less than 100 ppm boron, or less than 75 ppm boron, or less than 50 ppm boron, or less than 10 ppm boron, or about 0 ppm boron, based on the total weight of the lubricating oil composition.

In each of the second embodiments described above, the lubricating oil composition may have greater than 0 ppm boron and a ratio of total metals in ppm to total boron in ppm greater than 7.5, or greater than 50, or greater than 500.

In each of the foregoing embodiments, the lubricating oil composition may contain from 0 ppm to less than 100 ppm of boron, or from 0 ppm to less than 75 ppm of boron, or from 0 ppm to less than 50 ppm of boron, or from 0 ppm to less than 10 ppm of boron.

In each of the second embodiments described above, the one or more magnesium-containing detergents may be overbased having a total base number, as measured by the method of ASTM D-2896, of greater than 225 mg KOH/g, or greater than 250 mg KOH/g, or greater than 300 mg KOH/g, or greater than 350 mg KOH/g, or greater than 400 mg KOH/g.

In each of the second embodiments described above, the one or more calcium-containing detergents may, optionally, exclude a calcium salicylate detergent.

In each of the second embodiments described above, the one or more magnesium-containing detergents may be overbased magnesium sulfonate detergents having a total base number, as measured by the method of ASTM D-2896, of greater than 225 mg KOH/g, or greater than 250 mg KOH/g, or greater than 300 mg KOH/g, or greater than 350 mg KOH/g, or greater than 400 mg KOH/g.

In each of the second embodiments described above, the lubricating composition may be an engine oil composition.

To clarify the meaning of certain terms used in this specification, the following definitions are provided:

The terms "oil composition", "lubricating composition", "lubricating oil composition", "lubricating oil", "lubricant composition", "lubricating composition", "fully formulated lubricant composition", "lubricant", "crankcase oil", "crankcase lubricant", "engine oil", "engine lubricant", "motor oil", and "motor lubricant" are considered to be synonymous and fully interchangeable terms referring to a final lubricant product comprising a major amount of a base oil plus a minor amount of an additive composition.

As used herein, the terms "additive package", "additive concentrate", "additive composition", "engine oil additive package", "engine oil additive concentrate", "crankcase additive package", "crankcase additive concentrate", "motor oil additive package", "motor oil concentrate" are considered synonymous and fully interchangeable terms referring to that portion of a lubricating oil composition that excludes a major amount of a base oil stock blend. The additive package may or may not include a viscosity index improver or pour point depressant.

The term "overbased" refers to metal salts, e.g., of sulfonates, carboxylates, salicylates, and/or phenates, in which the amount of metal present exceeds the theoretical amount. Such salts may have a conversion rate of more than 100% (i.e., they may contain more than 100% of the theoretical amount of metal required to convert the acid to its "standard", "neutral" salt). The expression "metal ratio", often abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of metal in an overbased salt to the chemical equivalents of metal in a neutral salt, according to known chemical reactivity and stoichiometry. In standard or neutral salts, the metal ratio is 1, while in overbased salts, the MR is greater than 1. These are commonly referred to as overbased, hyperbased, or superbased salts, and may be salts of organic sulfur acids, carboxylic acids, salicylates, and/or phenols.

As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense known to those skilled in the art. Specifically, it refers to a group having a carbon atom directly attached to the remainder of the molecule and having a predominantly hydrocarbon character. Each hydrocarbyl group is independently selected from hydrocarbon substituents, the substituted hydrocarbon substituents containing one or more of halo, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen, and nitrogen, with no more than two non-hydrocarbon substituents present for every 10 carbon atoms in the hydrocarbyl group.

As used herein, the term "hydrocarbyl substituent" or "hydrocarbyl group" is used in its ordinary sense, well known to those skilled in the art. Specifically, it refers to a group that is directly attached to the remainder of the molecule by carbon atoms at two locations in the molecule and has predominantly hydrocarbon character. Each hydrocarbylene group is independently selected from divalent hydrocarbon substituents and substituted divalent hydrocarbon substituents including halo, alkyl, aryl, alkylaryl, arylalkyl, hydroxyl, alkoxy, mercapto, nitro, nitroso, amino, pyridyl, furyl, imidazolyl, oxygen and nitrogen, with no more than two non-hydrocarbon substituents present for every 10 carbon atoms in the hydrocarbylene group.

As used herein, the term "weight percent" means the percentage that the recited component represents by weight of the entire composition, unless expressly stated otherwise.

As used herein, the terms "soluble," "oil-soluble," or "dispersible" may, but do not necessarily, indicate that a compound or additive is soluble, dissolvable, miscible, or capable of being suspended in oil in any proportion. However, the foregoing terms mean that they are soluble, suspendable, dissolvable, or stably dispersible in oil to an extent sufficient to exert their intended effect in the environment in which the oil is extracted. Furthermore, the incorporation of additional other additives may allow for higher levels of incorporation of a particular additive, if desired.

As used herein, the term "TBN" is used to indicate the total base number in mg KOH/g as measured by the methods of ASTM D2896 or ASTM D4739 or DIN 51639-1.

As used herein, the term "alkyl" refers to straight, branched, cyclic, and/or substituted saturated chain moieties of from about 1 to about 100 carbon atoms.

As used herein, the term "alkenyl" refers to straight, branched, cyclic, and/or substituted unsaturated chain moieties of about 3 to about 10 carbon atoms.

As employed herein, the term "aryl" refers to monocyclic and polycyclic aromatic compounds that may contain alkyl, alkenyl, alkylaryl, amino, hydroxyl, alkoxy, halo substituents, and/or heteroatoms including, but not limited to, nitrogen, oxygen, and sulfur.

Diesel particulate filter clogging can be measured with the Volkswagen (VW) Diesel Particulate Filter Test (DFT), VW PV 1485. The VW PV 1485 test measures the amount of sulfate ash deposits that clog a vehicle's diesel particulate filter, reducing the life of the filter and resulting in increased back pressure in the vehicle engine and increased fuel consumption. The diesel particulate filter test measures the increase in back pressure versus oil consumption after 144 hours of an ash loading phase.

The reduction in low-speed pre-ignition events may be expressed as an "LSPI ratio." The term "LSPI ratio" refers to the ratio of the number of low-speed pre-ignition events in a boosted internal combustion engine lubricated with a lubricating oil composition of the present disclosure to the number of low-speed pre-ignition events in the same boosted internal combustion engine lubricated with the reference lubricant R-1 described herein. A lubricating oil composition that reduces the LSPI ratio is effective to reduce the number of low-speed pre-ignition events in a boosted internal combustion engine lubricated with the lubricating oil composition relative to the number of low-speed pre-ignition events in the same engine lubricated with the reference lubricant R-1.

The lubricants, combinations of components, or individual components herein may be suitable for use in various types of internal combustion engines. Suitable engine types may include, but are not limited to, heavy duty diesel, passenger car, light duty diesel, medium speed diesel, or marine engines. The internal combustion engine may be a diesel fueled engine, a gasoline fueled engine, a natural gas fueled engine, a biofuel engine, a mixed diesel/biofuel-fueled engine, a mixed gasoline/biofuel-fueled engine, an alcohol fueled engine, a mixed gasoline/alcohol fueled engine, a compressed natural gas (CNG) fueled engine, or mixtures thereof. The diesel engine may be a compression ignition engine. The gasoline engine may be a spark ignition engine, such as a boosted spark ignition engine. The internal combustion engine may also be used in combination with an electric or battery power source. Engines configured in this manner are commonly known as hybrid engines. The internal combustion engine may be a two-stroke, four-stroke, or rotary engine. Suitable internal combustion engines include marine diesel engines (e.g., inland marine), aviation piston engines, light duty diesel engines, and motorcycle, automobile, locomotive, and truck engines.

Passenger cars and light vehicles may be equipped with either compression (diesel) or spark-ignition (gasoline) internal combustion engines. Generally, engine oils are specially formulated for use in one or the other. However, it may be beneficial to lubricate a spark-ignition engine with an engine oil formulated for a diesel engine. In addition, some diesel engine oils have been tested to meet the specifications for both diesel and gasoline engine oils (i.e., blend specifications) and are therefore recommended for use in either engine type. Thus, oils that meet the specifications for both diesel and gasoline engines and can accommodate each of these diverse engine conditions are desirable.

The internal combustion engine may contain one or more components of aluminum alloys, lead, tin, copper, cast iron, magnesium, ceramics, stainless steel, composites, and/or mixtures thereof. The components may be coated, for example, with diamond-like carbon coatings, lubricating coatings, phosphorus-containing coatings, molybdenum-containing coatings, graphite coatings, nanoparticle-containing coatings, and/or mixtures thereof. The aluminum alloy may include aluminum silicate, aluminum oxide, or other ceramic materials. In one embodiment, the aluminum alloy is an aluminum silicate surface. As used herein, the term "aluminum alloy" is synonymous with "aluminum composite" and is intended to describe a component or surface that includes aluminum and other components that mix or react at a microscopic or near-microscopic level, regardless of its detailed structure. This includes any conventional alloy with metals other than aluminum, as well as composite or alloy-like structures with non-metallic elements or compounds, such as ceramic-like materials.

The lubricating oil composition for internal combustion engines may be suitable for any engine lubricant, regardless of sulfur, phosphorus, or ash content (ASTM D-874). The sulfur content of the engine oil lubricant may be about 1 wt.% or less, or about 0.8 wt.% or less, or about 0.5 wt.% or less, or about 0.3 wt.% or less, or about 0.2 wt.% or less. In one embodiment, the sulfur content may range from about 0.001 wt.% to about 0.5 wt.%, or about 0.01 wt.% to about 0.3 wt.%. The phosphorus content may be about 700 ppm to about 900 ppm, or 850 ppm or less. The total measured sulfated ash content may be 0.5 wt.% or more to 1.0 wt.% or less than 0.8 wt.%, or greater than 0.5 wt.% to less than 1.0 wt.%, or greater than 0.6 wt.% to less than 1.0 wt.%, as measured by ASTM D874. In another embodiment, the sulfur content may be about 0.4% or less by weight, the phosphorus content may be about 0.08% or less by weight, and the measured sulfated ash is greater than or equal to 0.5% by weight and less than or equal to about 1% by weight. In yet another embodiment, the sulfur content may be about 0.3% or less by weight, the phosphorus content may be about 0.05% or less by weight, and the measured sulfated ash is about 0.8% or less by weight.

In one embodiment, the lubricating oil composition is an engine oil, and the lubricating oil composition may have (i) a sulfur content of about 0.5 wt.% or less, (ii) a phosphorus content of about 0.1 wt.% or less, and (iii) a measured sulfated ash content of greater than or equal to 0.5 wt.% and less than or equal to 1.0 wt.%.

In one embodiment, the lubricating oil composition contains less than 10 ppm boron, or less than 50 ppm boron, or less than 10 ppm boron, or 0 ppm boron, based on the total weight of the lubricating oil composition. In another embodiment, the lubricating oil composition has greater than 0 ppm boron and the ratio of total metals in ppm to total boron in ppm is greater than 7.5, or greater than 50, or greater than 500.

In one embodiment, the lubricating oil composition is suitable for a two-stroke or four-stroke marine diesel internal combustion engine. In one embodiment, the marine diesel combustion engine is a two-stroke engine. In some embodiments, the lubricating oil composition is not suitable for a two-stroke or four-stroke marine diesel internal combustion engine for one or more reasons, including, but not limited to, the high sulfur content of the fuels used to power the marine engines and the high TBN required for marine engine oils (e.g., greater than about 40 TBN for marine engine oils).

In some embodiments, the lubricating oil composition is suitable for use in engines powered by low sulfur fuels, such as fuels containing about 1 to about 5% sulfur. Highway vehicle fuels contain about 15 ppm sulfur (or about 0.0015% sulfur).

Low-speed diesel typically refers to marine engines, medium-speed diesel generally refers to locomotives, and high-speed diesel typically refers to highway vehicles. The lubricating oil composition may be suitable for only one or all of these types.

Additionally, the lubricants herein may meet one or more industry specification requirements, such as ILSAC GF-3, GF-4, GF-5, GF-5+, GF-6, PC-11, CF, CK-4, FA-4, CF-4, CH-4, CI-4, CJ-4, API SG, SJ, SL, SM, SN, SN+, ACEA A1/B1, A2/B2, A3/B3, A3/B4, A5/B5, C1, C2, C3, C4, C5, E4/E6/E7/E9, Euro5/6, Jaso DL-1, Low SAPS, Mid SAPS, or Dexos™. 1, Dexos(TM) 2, MB-Approval229.1, 229.3, 229.5, 229.31, 229.51, 229.52, 229.6, 229.71, 226.5, 226.51, 228.0/. 1,228.2/. 3, 228.31, 228.5, 228, 51, 228.61, VW 501.01, 502.00, 503.00/503.01, 504.00, 505.00, 505.01, 506.00/506.01, 507.00, 508.00, 509.00, 508.88, 509.99, BMW Longlife-01, Longlife-01 FE, Longlife-04, Longlife-12 FE, Longlife-14 FE+, Longlife-17 FE+, Porsche A40, C30, Peugeot Citroen Automobiles B71 2290, B71 2294, B71 2295, B71 2296, B71 2297, B71 2300, B71 2302, B71 2312, B71 2007, B71 2008, Renault RN0700, RN0710, RN0720, Ford WSS-M2C153-H, WSS-M2C930-A, WSS-M2C945-A, WSS-M2C913A, WSS-M2C9 13-B, WSS-M2C913-C, WSS-M2C913-D, WSS-M2C948-B, WSS-M2C948-A, GM 6094-M, Chrysler MS-6395, Fiat 9.55535 G1, G2, M2, N1, N2, Z2, S1, S2, S3, S4, T2, DS1, DSX, GH2, GS1, GSX, CR1, Jaguar Land Rover STJLR. 03.5003, STJLR. 03.5004, STJLR. 03.5005, STJLR. 03.5006, STJLR. 03.5007, STJLR. 51.5122, or any past or future PCMO or HDD specifications not mentioned herein. In some embodiments for passenger car motor oil (PCMO) applications, the amount of phosphorus in the finished fluid is 1000 ppm or less, or 900 ppm or less, or 800 ppm or less.

Other hardware may not be suitable for use with the disclosed lubricants. The term "functional fluid" includes a variety of fluids, including but not limited to tractor hydraulic fluids, power transmission fluids including automatic transmission fluids, continuously variable transmission fluids and manual transmission fluids, hydraulic fluids including tractor hydraulic fluids, some gear oils, power steering fluids, wind turbines, fluids used in compressors, some industrial fluids, and fluids associated with power transmission components. It should be noted that within each of these fluids, such as automatic transmission fluids, there are a variety of different types of fluids for various transmissions having different designs that require fluids with significantly different functional properties. This is in contrast to the term "lubricating fluid," which is not used in the generation or transmission of power.

For example, with regard to hydraulic fluids in tractors, these fluids are general purpose products used for all lubrication applications in tractors except for lubricating the engine. These lubrication applications may include lubricating the gearbox, power take-offs and clutches, rear axles, reduction gears, wet brakes, and hydraulic accessories.

If the functional fluid is an automatic transmission fluid, the automatic transmission fluid must have enough friction for the clutch plates to transmit power. However, the coefficient of friction of the fluid tends to decrease due to the effects of temperature as the fluid heats up during operation. It is important that a tractor working fluid or automatic transmission fluid maintain a high coefficient of friction at high temperatures or else the braking system or automatic transmission may fail. This is not the function of engine oil.

Tractor fluids, such as Super Tractor Universal Oil (STUO) or Universal Tractor Transmission Oil (UTTO), may combine engine oil performance with transmission, differential, final drive planetary gear, wet brake, and hydraulic performance. Many of the additives used to formulate UTTO or STUO fluids are functionally similar but can have detrimental effects if not added properly. For example, certain anti-wear and extreme pressure additives used in engine oils are extremely corrosive to the copper components of hydraulic pumps. Detergents and dispersants used in gasoline or diesel engine performance can be detrimental to wet brake performance. Friction modifiers specific to quiet wet brake squeal may lack the thermal stability required for engine oil performance. Each of these fluids is designed to meet specific stringent manufacturer requirements, whether functional, tractor, or lubricity.

The present disclosure provides novel lubricant blends formulated for use as automotive crankcase lubricants. The present disclosure provides novel lubricant blends formulated for use as 2T and/or 4T motorcycle crankcase lubricants. Embodiments of the present disclosure provide lubricants suitable for use in crankcases and having improvements in air entrainment, alcohol fuel compatibility, antioxidant properties, antiwear performance, biofuel compatibility, foam reduction properties, friction reduction, fuel economy, pre-ignition prevention, rust inhibition, sludge and/or soot dispersancy, piston cleanliness, deposit formation, and water resistance properties.

The engine oils of the present disclosure may be formulated by adding one or more additives to a suitable base oil formulation, as described in detail below. The additives may be combined with the base oil in the form of an additive package (or concentrate), or alternatively may be combined individually with the base oil (or a mixture of both). The fully formulated engine oil may exhibit improved performance characteristics based on the additives added and the proportions of each.

Further details and advantages of the present disclosure are set forth in part in the following description and/or may be learned by practice of the present disclosure. The details and advantages of the present disclosure may be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present disclosure as claimed.

Various embodiments of the present disclosure provide lubricating oil compositions and methods for reducing clogging in diesel particulate filters. The lubricating oil compositions may be useful in compression (diesel) engines and/or spark ignition (gasoline) engines. In particular, engines in which the lubricating oil compositions may be used may include boosted internal combustion engines, such as turbocharged and supercharged internal combustion engines. Boosted internal combustion engines include spark ignition engines, direct injection engines, and/or port fuel injection engines. Preferably, the boosted internal combustion engine is a spark ignition internal combustion engine or a direct injection engine.

In a first aspect, the present disclosure provides a lubricating oil composition comprising greater than 50 wt. % of a base oil of lubricating viscosity, based on the total weight of the lubricating oil composition, as measured by ASTM D874, an amount of one or more calcium-containing detergents to provide less than 1700 ppm calcium, an amount of one or more magnesium-containing detergents to provide less than 450 ppm magnesium, an amount of one or more molybdenum-containing compounds to provide less than 450 ppm molybdenum, from about 700 ppm to about 900 ppm phosphorus, a total measured sulfated ash content of 1.0 wt. % or less, and a ratio in ppm of calcium from the one or more calcium-containing detergents to magnesium from the one or more magnesium-containing detergents of 1:1 or greater, all based on the total weight of the lubricating oil composition.

In a second aspect, the present invention relates to a method for reducing clogging in a diesel particulate filter, comprising operating an engine equipped with a diesel particulate filter and lubricated with a lubricating oil composition herein.

The aforementioned lubricant compositions and methods may provide diesel particulate filter delta pressure (ΔP) versus oil consumption results of 0.6 kPa/kg or less, 0.5 kPa/kg or less, or 0.45 kPa/kg or less after 144 hours, as measured by the VW PV 1485 test.

Preferably, the lubricating oil composition and method are also effective to reduce low speed pre-ignition events in a boosted internal combustion engine lubricated with the lubricating oil composition relative to several low speed pre-ignition events in the same engine lubricated with reference lubricant R-1, or to provide a reduction in LSPI events of 50% or more, the LSPI events being an LSPI count during 25,000 engine cycles, the engine operating at 2000 revolutions per minute with a brake mean effective pressure of 1,800 kPa.

As described in more detail below, embodiments of the present disclosure may provide significant and unexpected improvements in reducing clogging in diesel particulate filters, and, optionally, significant reductions in low speed pre-ignition events, while maintaining relatively high calcium detergent concentrations in the lubricating oil composition.

Base Oil The base oil used in the lubricating oil composition may be selected from any of the base oils in Groups I to V as specified in the American Petroleum Institute (API) Base Oil Interchangeability Guidelines. The five base oil groups are as follows:

Groups I, II, and III are mineral oil process stocks. Group IV base oils contain true synthetic molecular species produced by polymerization of olefinically unsaturated hydrocarbons. Many Group V base oils are also true synthetic products and may include diesters, polyol esters, polyalkylene glycols, alkylated aromatics, polyphosphate esters, polyvinyl ethers, and/or polyphenyl ethers, etc., but may also be naturally occurring oils such as vegetable oils. It should be noted that Group III base oils are derived from mineral oils, but the severe processing these fluids undergo makes their physical properties very similar to some true synthetics such as PAOs. Thus, oils derived from Group III base oils are sometimes referred to in the industry as synthetic fluids. Group II+ may include high viscosity index Group II.

The base oil used in the disclosed lubricating oil compositions can be mineral oils, animal oils, vegetable oils, synthetic oils, synthetic oil blends or mixtures thereof. Suitable oils can be derived from hydrocracked, hydrogenated, hydrofinished, unrefined, refined and rerefined oils, and mixtures thereof.

Unrefined oils are derived from natural, mineral, or synthetic sources without or little to no further refinement processing. Refined oils are similar to unrefined oils except that they have been treated with one or more purification steps that may result in the improvement of one or more properties. Examples of suitable refining techniques are solvent extraction, secondary distillation, acid or base extraction, filtration, percolation, and the like. Oils refined to edible quality may or may not be useful. Edible oils may also be referred to as white oils. In some embodiments, the lubricating oil composition does not include edible oils or white oils.

Re-refined oils are also known as reclaimed or reprocessed oils. These oils are similar to refined oils obtained using the same or similar processes. Additionally, these oils are further processed by techniques for the removal of spent additives and oil breakdown products.

Mineral oils may include oils obtained by drilling or from plants and animals, or any mixtures thereof. For example, such oils include, but are not limited to, mineral lubricating oils such as castor oil, lard oil, olive oil, peanut oil, corn oil, soybean oil, and linseed oil, as well as liquid petroleum, solvent-treated or acid-treated mineral lubricating oils of the paraffinic, naphthenic, or mixed paraffinic-naphthenic type. If necessary, such oils may be partially or fully hydrogenated. Oils derived from coal or shale may also be useful.

Useful synthetic lubricating oils may include hydrocarbon oils such as polymerized, oligomerized, or interpolymerized olefins (e.g., polybutylene, polypropylene, propylene isobutylene copolymers); poly(1-hexene), poly(1-octene), trimers or oligomers of 1-decene, e.g., poly(1-decene) (such materials are often referred to as alpha-olefins), and mixtures thereof; alkyl-benzenes (e.g., dodecylbenzene, tetradecylbenzene, dinonylbenzene, di-(2-ethylhexyl)-benzene); polyphenyls (e.g., biphenyls, terphenyls, alkylated polyphenyls); diphenylalkanes, alkylated diphenylalkanes, alkylated diphenyl ethers, and alkylated diphenyl sulfides, and derivatives, analogs, and homologs thereof, or mixtures thereof. Polyalphaolefins are typically hydrogenated materials.

Other synthetic lubricating oils include polyol esters, diesters, liquid esters of phosphorus-containing acids (e.g., tricresyl phosphate, trioctyl phosphate, diethyl ester of decane phosphonic acid), or polymeric tetrahydrofurans. Synthetic oils may be produced by Fischer-Tropsch reactions and typically are hydroisomerized Fischer-Tropsch hydrocarbons or waxes. In an embodiment, the oils can be prepared by Fischer-Tropsch gas-to-liquid synthesis procedures as well as other gas-to-liquid oils.

The major amount of base oil included in the lubricating composition may be selected from the group consisting of Group I, Group II, Group III, Group IV, Group V, and combinations of two or more of the foregoing, where the major amount of base oil is other than the base oil resulting from the provision of additive components or viscosity index improvers in the composition. In another embodiment, the major amount of base oil included in the lubricating composition may be selected from the group consisting of Group II, Group III, Group IV, Group V, and combinations of two or more of the foregoing, where the major amount of base oil is other than the base oil resulting from the provision of additive components or viscosity index improvers in the composition.

The amount of oil of lubricating viscosity present may be the remainder remaining after subtracting the sum of the amounts of performance additives, including viscosity index improvers and/or pour point depressants and/or other top treatment additives, from 100% by weight. For example, the oil of lubricating viscosity may be present in the final fluid in a major amount, such as greater than about 50% by weight, greater than about 60% by weight, greater than about 70% by weight, greater than about 80% by weight, greater than about 85% by weight, or greater than about 90% by weight.

Detergents The lubricating oil composition comprises one or more calcium-containing detergents and, optionally, one or more magnesium-containing detergents. The one or more calcium-containing detergents and the one or more magnesium-containing detergents may be independently selected from neutral, underbased, or overbased detergents, and mixtures thereof. Suitable detergent substrates include phenates, sulfur-containing phenates, sulfonic acids, calixarates, salixarates, salicylic acids, carboxylic acids, phosphoric acids, mono- and/or dithiophosphoric acids, alkylphenols, sulfur-bound alkylphenol compounds, or methylene-bridged phenols. Suitable detergents and methods for their preparation are described in more detail in numerous patent publications, including US Pat. No. 7,732,390 and references cited therein.

The detergent substrate may be basified with an alkali or alkaline earth metal, such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or mixtures thereof. In some embodiments, the detergent does not contain barium. Suitable detergents may include alkali or alkaline earth metal salts of petroleum sulfonic acids, and long chain mono- or di-alkylaryl sulfonic acids, where the aryl groups are benzyl, tolyl, and xylyl. Examples of suitable additional detergents include, but are not limited to, calcium phenates, calcium sulfur-containing phenates, calcium sulfonates, calcium calixarates, calcium salixarates, calcium salicylates, calcium carboxylates, calcium phosphates, calcium mono- and/or dithiophosphates, calcium alkylphenols, calcium sulfur-bound alkylphenol compounds, calcium methylene bridged phenols, magnesium phenates, magnesium sulfur-containing phenates, magnesium sulfonates, magnesium calixarates, magnesium salixarates, magnesium salicylates, magnesium carboxylates, magnesium phosphates, magnesium mono- and/or dithiophosphates, magnesium alkylphenols, magnesium sulfur-bound alkylphenol compounds, magnesium methylene bridged phenols, sodium phenates, sodium sulfur-containing phenates, sodium sulfonates, sodium calixarates, sodium salixarates, sodium salicylates, sodium carboxylates, sodium phosphates, sodium mono- and/or dithiophosphates, sodium alkylphenols, sodium sulfur-bound alkylphenol compounds, or sodium methylene bridged phenols.

Overbased detergents are known in the art and may be alkali or alkaline earth metal overbased detergent additives. Such detergent additives may be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.

The term "overbased" refers to metal salts such as metal salts of sulfonates, carboxylates, and phenates, in which the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level of more than 100% (i.e., they may contain more than 100% of the theoretical amount of metal required to convert the acid to its "standard" or "neutral" salt). The expression "metal ratio", often abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of metal in an overbased salt to the chemical equivalents of metal in a neutral salt, according to known chemical reactivity and stoichiometry. In standard or neutral salts, the metal ratio is 1, whereas in overbased salts, the MR is greater than 1. These are commonly referred to as overbased, hyperbased, or superbased salts, and may be salts of organic sulfur acids, carboxylic acids, or phenols.

The overbased detergent of the lubricating oil composition may have a total base number (TBN) of about 200 mg KOH/gram or more, or, as a further example, about 250 mg KOH/gram or more, or about 350 mg KOH/gram or more, or about 375 mg KOH/gram or more, or about 400 mg KOH/gram or more.

Examples of suitable overbased detergents include, but are not limited to, overbased calcium phenates, overbased calcium sulfur-containing phenates, overbased calcium sulfonates, overbased calcium calixarates, overbased calcium salixarates, overbased calcium salicylates, overbased calcium carboxylates, overbased calcium phosphates, overbased calcium mono- and/or dithiophosphoric acids, overbased calcium alkyl phenols, overbased calcium sulfur-bound alkyl phenol compounds, overbased calcium methylene-bridged phenols, overbased magnesium phenates, overbased magnesium sulfur-containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphates, overbased magnesium mono- and/or dithiophosphoric acids, overbased magnesium alkyl phenols, overbased magnesium sulfur-bound alkyl phenol compounds, overbased magnesium methylene-bridged phenols.

Overbased calcium detergents may have a total base number of at least about 150 mg KOH/g, at least about 225 mg KOH/g, at least 225 mg KOH/g to about 400 mg KOH/g, at least about 225 mg KOH/g to about 350 mg KOH/g, or from about 230 to about 350 mg KOH/g, all measured by the method of ASTM D-2896. When such detergent compositions are formed with an inert diluent, such as a process oil, usually a mineral oil, the total base number reflects the basicity of the entire composition, including the diluent and any other materials (e.g., accelerators, etc.) that may be contained in the detergent composition.

The overbased detergent may have a metal to substrate ratio of from 1.1:1, or from 2:1, or from 4:1, or from 5:1, or from 7:1, or from 10:1.

In some embodiments, the detergent is effective in reducing or preventing rust in an engine.

The total detergent may be present at up to 10 wt.%, or about 8 wt.%, or up to about 4 wt.%, or from greater than about 4 wt.% to about 8 wt.%, based on the total weight of the lubricating oil composition.

The one or more calcium-containing detergents may be present in an amount to provide less than 1700 ppm calcium, or less than 1670 ppm calcium, or less than 1500 ppm calcium, or less than 1400 ppm calcium, or greater than 1350 ppm to less than 1700 ppm calcium, or greater than 1350 ppm to less than 1670 ppm calcium, or greater than 1350 ppm to less than 1500 ppm calcium, or greater than 1350 ppm to less than 1400 ppm calcium, based on the total weight of the lubricating oil composition.

In some embodiments, one or more calcium-containing detergents are overbased, having a total base number of greater than 200 mg KOH/g, greater than 225 mg KOH/g, or greater than 250 mg KOH/g, as measured by the method of ASTM D-2896.

In some embodiments, the one or more calcium-containing detergents exclude calcium salicylate.

In another embodiment, the lubricating oil composition may contain one or more calcium-containing detergents having a total base number of up to 175 mg KOH/g as measured by the method of ASTM D-2896, providing less than 50 ppm calcium, or less than 20 ppm calcium, or less than 5 ppm calcium, or about 0 ppm calcium, based on the total weight of the lubricating oil composition.

The one or more magnesium-containing detergents may be present in an amount to provide less than 450 ppm magnesium, or no more than 450 ppm magnesium, or no more than 440 ppm magnesium, or no more than 430 ppm magnesium, or no more than 420 ppm magnesium, or no more than 410 ppm magnesium, or no more than 400 ppm magnesium, or no more than 350 ppm magnesium, or no more than 300 ppm magnesium.

In some embodiments, one or more magnesium-containing detergents are overbased having a total base number, as measured by the method of ASTM D-2896, of greater than 225 mg KOH/g, or greater than 250 mg KOH/g, or greater than 300 mg KOH/g, or greater than 350 mg KOH/g, or greater than 400 mg KOH/g.

In other embodiments, the one or more magnesium-containing detergents are overbased magnesium sulfonate detergents having a total base number, as measured by the method of ASTM D-2896, of greater than 225 mg KOH/g, or greater than 250 mg KOH/g, or greater than 300 mg KOH/g, or greater than 350 mg KOH/g, or greater than 400 mg KOH/g.

In some embodiments, the ratio of calcium from one or more calcium-containing detergents to magnesium from one or more magnesium-containing detergents, in ppm, is 1 or more, or greater than 2.0, or greater than 2.5, or greater than 3.0, or greater than 3.5, or less than 10.0, or less than 9.0, or less than 8.5, or greater than 1.0 to less than 10.0.

In alternative embodiments, the lubricating oil composition optionally contains 15 ppm or less of magnesium, or 10 ppm or less of magnesium from a detergent.

Molybdenum-Containing Component The lubricating oil composition herein comprises one or more molybdenum-containing compounds. The oil-soluble molybdenum compounds may have the functional properties of antiwear agents, antioxidants, friction modifiers, or mixtures thereof. The oil-soluble molybdenum compounds may comprise molybdenum dithiocarbamates, molybdenum dialkyl dithiophosphates, molybdenum dithiophosphinates, amine salts of molybdenum compounds, molybdenum xanthates, molybdenum thioxanthones, molybdenum sulfides, molybdenum carboxylates, molybdenum alkoxides, trinuclear organomolybdenum compounds, and/or mixtures thereof. The molybdenum sulfides comprise molybdenum disulfide. The molybdenum disulfide may be in the form of a stable dispersion. In one embodiment, the oil-soluble molybdenum compounds may be selected from the group consisting of molybdenum dithiocarbamates, molybdenum dialkyl dithiophosphates, amine salts of molybdenum compounds, and mixtures thereof. In one embodiment, the oil-soluble molybdenum compounds may be molybdenum dithiocarbamates.

Suitable examples of molybdenum compounds that may be used include commercially available materials sold under trade names such as Molyvan 822™, Molyvan™ A, Molyvan 2000 ^™ , and Molyvan 855™ available from R. T. Vanderbilt Co., Ltd., and Sakura-Lube™ S-165, S-200, S-300, S-310G, S-525, S-600, S-700, and S-710 available from Adeka Corporation, and mixtures thereof. Suitable molybdenum components are described in US 5,650,381, US RE 37,363E1, US RE 38,929E1 and US RE 40,595E1, which are incorporated herein by reference in their entirety. Preferably, the one or more molybdenum-containing compounds may be a reaction product of a fatty acid ester and a molybdenum oxide. Preferably, the fatty acid ester has 4 to 30 carbon atoms, or 6 to 20 carbon atoms.

Additionally, the molybdenum compound may be an acidic molybdenum compound. Included are sodium hydrogen molybdate, MoOCl4, MoO2Br2, Mo2O3Cl6, molybdenum trioxide or similar acidic molybdenum compounds, molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, and other alkali metal molybdates and other molybdenum salts. Alternatively, the composition can be provided with molybdenum from molybdenum/sulfur complexes of basic nitrogen compounds as described, for example, in U.S. Pat. Nos. 4,263,152, 4,285,822, 4,283,295, 4,272,387, 4,265,773, 4,261,843, 4,259,195, and 4,259,194, and WO 94/06897, which are incorporated herein by reference in their entireties.

Another class of suitable organomolybdenum compounds are trinuclear molybdenum compounds and mixtures thereof, such as compounds of the formula Mo3SkLnQz, where S represents sulfur, L represents an independently selected ligand having sufficient carbon atoms in the organic group to render the compound soluble or dispersible in oil, n is 1 to 4, k is 4 to 7, Q is selected from the group of neutral electron donor compounds such as water, amines, alcohols, phosphines and ethers, and z ranges from 0 to 5, including non-stoichiometric values. There may be at least 21 total carbon atoms in the organic groups of all the ligands, such as at least 25, at least 30, or at least 35 carbon atoms. Additional suitable molybdenum compounds are described in U.S. Pat. No. 6,723,685, the entire contents of which are incorporated herein by reference.

The oil-soluble molybdenum compound may be present in an amount sufficient to provide less than about 450 ppm, or less than about 420 ppm, or less than about 400 ppm, or less than about 390 ppm molybdenum, or greater than 5 ppm molybdenum, or greater than 50 ppm molybdenum, or greater than 80 ppm molybdenum, or greater than 100 ppm molybdenum, or greater than 5 ppm to less than 450 ppm molybdenum, or greater than 50 ppm to less than 420 ppm molybdenum, or greater than 80 ppm to less than 400 ppm molybdenum, or greater than 100 ppm to less than 390 ppm molybdenum, based on the total weight of the lubricating oil composition.

The lubricating oil composition may also contain one or more optional components selected from the various additives described below.

Boron-Containing Compounds The lubricating oil compositions herein may optionally contain one or more boron-containing compounds.

Examples of boron-containing compounds include borate esters, borated fatty amines, borated epoxides, borated detergents, and borated dispersants such as borated succinimide dispersants, as disclosed in U.S. Pat. No. 5,883,057.

When present, the boron-containing compound can be used in an amount sufficient to provide up to about 8 wt. %, about 0.01 wt. % to about 7 wt. %, about 0.05 wt. % to about 5 wt. %, or about 0.1 wt. % to about 3 wt. % of the lubricating oil composition.

In some embodiments of the present invention, the lubricating oil composition may contain less than 100 ppm boron, or less than 75 ppm boron, or less than 50 ppm boron, or less than 10 ppm boron, or about 0 ppm boron, based on the total weight of the lubricating oil composition.

In some embodiments, the lubricating oil composition may have greater than 0 ppm boron and a ratio of total metals in ppm to total boron in ppm greater than 7.5, or greater than 50, or greater than 500.

Antioxidants The lubricating oil compositions herein may also optionally contain one or more antioxidants. Antioxidant compounds are known and include, for example, phenates, phenate sulfides, sulfurized olefins, phosphosulfurized terpenes, sulfurized esters, aromatic amines, alkylated diphenylamines (e.g., nonyldiphenylamine, di-nonyldiphenylamine, octyldiphenylamine, di-octyldiphenylamine), phenyl-alpha-naphthylamines, alkylated phenyl-alpha-naphthylamines, hindered non-aromatic amines, phenols, hindered phenols, oil-soluble molybdenum compounds, polymeric antioxidants, or mixtures thereof. The antioxidant compounds may be used alone or in combination.

The hindered phenol antioxidant may contain secondary and/or tertiary butyl groups as sterically hindering groups. The phenol group may be further substituted with hydrocarbyl groups and/or bridging groups linking to a second aromatic group. Examples of suitable hindered phenol antioxidants include 2,6-di-tert-butylphenol, 4-methyl-2,6-di-tert-butylphenol, 4-ethyl-2,6-di-tert-butylphenol, 4-propyl-2,6-di-tert-butylphenol or 4-butyl-2,6-di-tert-butylphenol, or 4-dodecyl-2,6-di-tert-butylphenol. In one embodiment, the hindered phenol antioxidant may be an ester and may include, for example, Irganox™ L-135 available from BASF, or an addition product derived from 2,6-di-tert-butylphenol and an alkyl acrylate, where the alkyl group may contain from about 1 to about 18, or from about 2 to about 12, or from about 2 to about 8, or from about 2 to about 6, or about 4 carbon atoms. Another commercially available hindered phenol antioxidant may be an ester and may include Ethanox ^™ 4716 available from Albemarle Corporation.

Useful antioxidants may include diarylamines and high molecular weight phenols. In one embodiment, the lubricating oil composition may contain a mixture of diarylamines and high molecular weight phenols, such that each antioxidant may be present in an amount sufficient to provide up to about 5 wt. %, based on the final weight of the lubricating oil composition. In one embodiment, the antioxidant may be a mixture of about 0.3 to about 1.5 wt. % diarylamines and about 0.4 to about 2.5 wt. % high molecular weight phenols, based on the final weight of the lubricating oil composition.

Examples of suitable olefins that can be sulfurized to form sulfurized olefins include propylene, butylene, isobutylene, polyisobutylene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, tridecene, tetradecene, pentadecene, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof. In one embodiment, hexadecene, heptadecene, octadecene, nonadecene, eicosene, or mixtures thereof, as well as dimers, trimers, and tetramers thereof, are particularly useful olefins. Alternatively, the olefins may be Diels-Alder adducts of dienes such as 1,3-butadiene and unsaturated esters such as butyl acrylate.

Another class of sulfurized olefins includes sulfurized fatty acids and their esters. The fatty acids are often derived from vegetable or animal oils and typically contain from about 4 to about 22 carbon atoms. Examples of suitable fatty acids and their esters include triglycerides, oleic acid, linoleic acid, palmitoleic acid, or mixtures thereof. Often the fatty acids are derived from lard oil, tall oil, peanut oil, soybean oil, cottonseed oil, sunflower seed oil, or mixtures thereof. The fatty acids and/or esters may be mixed with olefins such as alpha-olefins.

In another alternative embodiment, the antioxidant composition also includes a molybdenum-containing antioxidant in addition to the phenolic and/or aminic antioxidants described above. When a combination of these three antioxidants is used, preferably the ratio of phenolic, amine, and molybdenum-containing is (0-2):(0-2):(0-1).

The one or more antioxidants may be present in a range of about 0 wt. % to about 20 wt. %, or about 0.1 wt. % to about 10 wt. %, or about 0.6 wt. % to about 5 wt. %, or about 1.0 wt. % to about 3 wt. % of the lubricating oil composition.

Antiwear Agents The lubricating oil compositions herein may also optionally contain one or more antiwear agents. Examples of suitable antiwear agents include, but are not limited to, metal thiophosphates, metal dialkyldithiophosphates, phosphate esters or salts thereof, phosphate esters, phosphites, phosphorus-containing carboxylic acid esters, ethers, or amides, sulfurized olefins, thiocarbamate esters, alkylene-linked thiocarbamates, and thiocarbamate-containing compounds including bis(S-alkyldithiocarbamyl) disulfides, and mixtures thereof. A suitable antiwear agent may be molybdenum dithiocarbamate. Phosphorus-containing antiwear agents are described in more detail in EP 612839. The metal in the dialkyldithiophosphate salt may be an alkali metal, alkaline earth metal, aluminum, lead, tin, molybdenum, manganese, nickel, copper, titanium, or zinc. A useful antiwear agent may be zinc dialkyldithiophosphate.

Further examples of suitable antiwear agents include titanium compounds, tartrates, tartrimides, oil-soluble amine salts of phosphorus compounds, sulfurized olefins, phosphites (e.g., dibutyl phosphite), phosphonates, thiocarbamate-containing compounds such as thiocarbamic acid esters, thiocarbamic acid amides, thiocarbamic acid ethers, alkylene-linked thiocarbamates, and bis(S-alkyldithiocarbamyl) disulfides. The tartrates or tartrimides can contain alkyl-ester groups, and the total of carbon atoms on the alkyl groups can be at least 8. The antiwear agent may include citrates in one embodiment.

The antiwear agent may be present in a range including about 0 wt. % to about 15 wt. %, or about 0.01 wt. % to about 10 wt. %, or about 0.05 wt. % to about 5 wt. %, or about 0.1 wt. % to about 3 wt. % of the lubricating oil composition.

Additional Optional Detergents The lubricating oil composition may include one or more neutral and/or low-based detergents, as well as overbased detergents that are free of calcium and mixtures thereof. Suitable detergent substrates include phenates, sulfur-containing phenates, sulfonic acids, calixarates, salixarates, salicylic acids, carboxylic acids, phosphoric acids, mono- and/or dithiophosphoric acids, alkylphenols, sulfur-bound alkylphenol compounds, or methylene-bridged phenols. Suitable detergents and methods for their preparation are described in more detail in numerous patent publications, including US 7,732,390 and the references cited therein. The detergent substrate may be basified with an alkali or alkaline earth metal, such as, but not limited to, calcium, magnesium, potassium, sodium, lithium, barium, or mixtures thereof. In some embodiments, the detergent does not contain barium. Suitable detergents may include alkali or alkaline earth metal salts of petroleum sulfonic acids, and long chain mono- or dialkylaryl sulfonic acids, where the aryl group is benzyl, tolyl, and xylyl. Examples of suitable detergents include, but are not limited to, calcium phenate, calcium sulfur-containing phenate, calcium sulfonate, calcium calixarate, calcium salixarate, calcium salicylate, calcium carboxylate, calcium phosphate, calcium mono- and/or dithiophosphate, calcium alkylphenol, calcium sulfur-bound alkylphenol compound, calcium methylene bridged phenol, magnesium phenate, magnesium sulfur-containing phenate, magnesium sulfonate, magnesium calixarate, magnesium salixarate, magnesium salicylate, magnesium carboxylate, magnesium phosphate, magnesium mono- and/or dithiophosphate, magnesium alkylphenol, magnesium sulfur-bound alkylphenol compound, magnesium methylene bridged phenol, sodium phenate, sodium sulfur-containing phenate, sodium sulfonate, sodium calixarate, sodium salixarate, sodium salicylate, sodium carboxylate, sodium phosphate, sodium mono- and/or dithiophosphate, sodium alkylphenol, sodium sulfur-bound alkylphenol compound, or sodium methylene bridged phenol.

Overbased detergent additives are known in the art and may be alkali or alkaline earth metal overbased detergent additives. Such detergent additives may be prepared by reacting a metal oxide or metal hydroxide with a substrate and carbon dioxide gas. The substrate is typically an acid, such as an aliphatic substituted sulfonic acid, an aliphatic substituted carboxylic acid, or an aliphatic substituted phenol.

The term "overbased" refers to metal salts such as metal salts of sulfonates, carboxylates, and phenates, in which the amount of metal present exceeds the stoichiometric amount. Such salts may have a conversion level of more than 100% (i.e., they may contain more than 100% of the theoretical amount of metal required to convert the acid to its "standard" or "neutral" salt). The expression "metal ratio", often abbreviated as MR, is used to indicate the ratio of the total chemical equivalents of metal in an overbased salt to the chemical equivalents of metal in a neutral salt, according to known chemical reactivity and stoichiometry. In standard or neutral salts, the metal ratio is 1, whereas in overbased salts, the MR is greater than 1. These are commonly referred to as overbased, hyperbased, or superbased salts, and may be salts of organic sulfur acids, carboxylic acids, or phenols.

The overbased detergent of the lubricating oil composition may have a total base number (TBN) of greater than about 225 mg KOH/gram, or, as a further example, greater than or equal to about 250 mg KOH/gram, or greater than or equal to about 350 mg KOH/gram, or greater than or equal to about 375 mg KOH/gram, or greater than or equal to about 400 mg KOH/gram.

Examples of suitable overbased detergents include, but are not limited to, overbased magnesium phenates, overbased magnesium sulfur-containing phenates, overbased magnesium sulfonates, overbased magnesium calixarates, overbased magnesium salixarates, overbased magnesium salicylates, overbased magnesium carboxylic acids, overbased magnesium phosphates, overbased magnesium mono- and/or di-thiophosphates, overbased magnesium alkylphenols, overbased magnesium sulfur-linked alkylphenol compounds, or overbased magnesium methylene-bridged phenols.

The overbased detergent may have a metal to substrate ratio of from 1.1:1, or from 2:1, or from 4:1, or from 5:1, or from 7:1, or from 10:1.

The low-based/neutral detergent has a TBN of up to 175 mg KOH/g, or up to 150 mg KOH/g. The low-based/neutral detergent may include a calcium-containing detergent. The low-based neutral calcium-containing detergent may be selected from calcium sulfonate detergents, calcium phenate detergents, and calcium salicylate detergents. In some embodiments, the low-based/neutral detergent is a calcium-containing detergent or a mixture of calcium-containing detergents. In some embodiments, the low-based/neutral detergent is a calcium sulfonate detergent or a calcium phenate detergent.

The low based/neutral detergents may comprise at least 2.5 wt.% of the total detergents in the lubricating oil composition. In some embodiments, at least 4 wt.%, or at least 6 wt.%, or at least 8 wt.%, or at least 10 wt.%, or at least 12 wt.%, or at least 20 wt.% of the total detergents in the lubricating oil composition are low based/neutral detergents, which may optionally be low based/neutral calcium-containing detergents.

In certain embodiments, one or more low based/neutral detergents provide the lubricating oil composition with about 50 to about 1000 ppm by weight of calcium, based on the total weight of the lubricating oil composition. In some embodiments, one or more low based/neutral calcium-containing detergents provide the lubricating oil composition with 75 to less than 800 ppm by weight, or 100 to 600 ppm by weight, or 125 to 500 ppm by weight of calcium, based on the total weight of the lubricating oil composition.

In some embodiments, the detergent is effective in reducing or preventing rust in an engine.

Dispersants The lubricating oil composition may optionally further comprise one or more dispersants or mixtures thereof. Dispersants are often referred to as ashless type dispersants because they do not contain ash-forming metals prior to mixing into the lubricating oil composition and do not normally contribute to ash when added to the lubricant. Ashless type dispersants are characterized by a polar group attached to a relatively high molecular weight hydrocarbon chain, polymer, or copolymer. Typical ashless dispersants include N-substituted long chain alkenyl succinimides. Examples of N-substituted long chain alkenyl succinimides include polyisobutylene succinimides in which the polyisobutylene substituent has a number average molecular weight in the range of about 350 to about 50,000, or 350 to about 5,000, or 350 to about 3,000, and polyalphaolefin succinimides in which the polyalphaolefin substituent has a number average molecular weight in the range of about 350 to about 10,000, or 350 to about 5,000, or 350 to about 3,000, as measured by gel permeation chromatography (GPC) using polystyrene as the calibration standard. Suitable polyalphaolefins include ethylene-alphaolefin copolymers, such as ethylene-propylene copolymers.

Succinimide dispersants and their preparation are disclosed, for example, in U.S. Pat. No. 7,897,696 or U.S. Pat. No. 4,234,435. Polyolefins can be prepared from polymerizable monomers containing from about 2 to about 16, or from about 2 to about 8, or from about 2 to about 6 carbon atoms. Succinimide dispersants are typically imides formed from polyamines, typically poly(ethyleneamines).

Preferred amines are selected from polyamines and hydroxyamines. Examples of polyamines that can be used include, but are not limited to, diethylenetriamine (DETA), triethylenetetramine (TETA), tetraethylenepentamine (TEPA), and higher homologs such as pentaethylaminehexamine (PEHA).

Suitable heavy polyamines are mixtures of polyalkylene-polyamines containing small amounts of lower polyamine oligomers such as TEPA and PEHA (pentaethylenehexamine), but primarily oligomers with 6 or more nitrogen atoms, 2 or more primary amines per molecule, and more extensive branching than conventional polyamine mixtures. Heavy polyamines preferably include polyamine oligomers containing 7 or more nitrogens per molecule and 2 or more primary amines per molecule. Heavy polyamines contain greater than 28% by weight (e.g., greater than 32% by weight) total nitrogen and an equivalent weight of 120-160 grams of primary amine groups per equivalent.

Suitable polyamines are commonly known as PAM and contain a mixture of ethyleneamines, with TEPA and pentaethylenehexamine (PEHA) being the majority of the polyamine, usually less than about 80%.

Typically, PAM has 8.7-8.9 milliequivalents of primary amine per gram (115-112 grams equivalent per equivalent of primary amine) and a total nitrogen content of about 33-34% by weight. Heavier cuts of PAM oligomers, containing essentially no TEPA and only small amounts of PEHA, but primarily oligomers with 6 or more nitrogens and more extensive branching, may produce dispersants with improved dispersing properties.

In one embodiment, the disclosure further includes at least one polyisobutylene succinimide dispersant derived from polyisobutylene having a number average molecular weight ranging from about 350 to about 50,000, or from about 5000, or from about 3000, as measured by gel permeation chromatography (GPC) using polystyrene as a calibration standard. The polyisobutylene succinimide may be used alone or in combination with other dispersants.

In some embodiments, polyisobutylene, when present, may have a terminal double bond content of greater than 50 mol%, greater than 60 mol%, greater than 70 mol%, greater than 80 mol%, or greater than 90 mol%. Such PIB is also referred to as highly reactive PIB ("HR-PIB"). HR-PIB having a number average molecular weight in the range of about 800 to about 5000 is suitable for use in embodiments of the present disclosure. Conventional PIB typically has a terminal double bond content of less than 50 mol%, less than 40 mol%, less than 30 mol%, less than 20 mol%, or less than 10 mol%.

HR-PIB having a number average molecular weight ranging from about 900 to about 3000 may be suitable. Such HR-PIB is commercially available or can be synthesized by polymerization of isobutene in the presence of a non-chlorinated catalyst such as boron trichloride as described in U.S. Pat. No. 4,152,499 to Boerzel et al. and U.S. Pat. No. 5,739,355 to Gateau et al. When used in the aforementioned thermal ene reaction, HR-PIB can result in higher conversions in the reaction and less formation of precipitate due to increased reactivity. A suitable method is described in U.S. Pat. No. 7,897,696.

In one embodiment, the disclosure further comprises at least one dispersant derived from polyisobutylene succinic anhydride ("PIBSA"). The PIBSA may have an average of about 1.0 to about 2.0 succinic acid moieties per polymer.

The percent activity of the alkenyl or alkyl succinic anhydride can be measured using chromatographic techniques. This method is described in U.S. Pat. No. 5,334,321, columns 5 and 6.

The polyolefin conversion is calculated from the % actives using the formula in columns 5 and 6 of U.S. Patent No. 5,334,321.

Unless otherwise noted, all percentages are weight percent and all molecular weights are number average molecular weight.

In one embodiment, the dispersant may be derived from polyalphaolefin (PAO) succinic anhydride.

In one embodiment, the dispersant may be derived from an olefin maleic anhydride copolymer. As an example, the dispersant may be described as polyPIBSA.

In one embodiment, the dispersant may be derived from an anhydride that is grafted to an ethylene-propylene copolymer.

One class of suitable dispersants may be Mannich bases. Mannich bases are materials formed by the condensation of higher molecular weight alkyl substituted phenols, polyalkylene polyamines, and aldehydes such as formaldehyde. Mannich bases are described in more detail in U.S. Pat. No. 3,634,515.

A suitable class of dispersants may be high molecular weight esters or half ester amides.

Suitable dispersants may also be post-treated by conventional methods with any of a variety of agents. Among these are boron, urea, thiourea, dimercaptothiadiazoles, carbon disulfide, aldehydes, ketones, carboxylic acids, hydrocarbon-substituted succinic anhydrides, maleic anhydride, nitriles, epoxides, carbonates, cyclic carbonates, hindered phenol esters, and phosphorus compounds. US 7,645,726, US 7,214,649, and US 8,048,831 are incorporated herein by reference in their entireties.

In addition to the carbonate and boric acid post-treatments, any of the compounds may be post-treated or further post-treated with a variety of post-treatments designed to improve or impart different properties. Such post-treatments include those summarized in columns 27-29 of U.S. Patent No. 5,241,003, which is incorporated herein by reference. Such treatments include:
Inorganic phosphoric acids or anhydrides (e.g., U.S. Pat. Nos. 3,403,102 and 4,648,980);
Organophosphorus compounds (e.g., U.S. Pat. No. 3,502,677);
Phosphorus pentasulfide,
The boron compounds already mentioned above (e.g., U.S. Pat. Nos. 3,178,663 and 4,652,387);
carboxylic acids, polycarboxylic acids, anhydrides, and/or acid halides (e.g., U.S. Pat. Nos. 3,708,522 and 4,948,386);
epoxides, polyepoxides, or thioepoxides (e.g., U.S. Pat. Nos. 3,859,318 and 5,026,495);
Aldehydes or ketones (e.g., U.S. Pat. No. 3,458,530);
Carbon disulfide (e.g., U.S. Pat. No. 3,256,185);
glycidol (e.g., U.S. Pat. No. 4,617,137);
urea, thiourea, or guanidine (e.g., U.S. Pat. Nos. 3,312,619, 3,865,813, and British Patent No. GB 1,065,595);
Organic sulfonic acids (e.g., U.S. Pat. No. 3,189,544 and British Patent No. GB 2,140,811);
Alkenyl cyanides (e.g., U.S. Pat. Nos. 3,278,550 and 3,366,569);
Diketene (e.g., U.S. Pat. No. 3,546,243);
diisocyanates (e.g., U.S. Pat. No. 3,573,205);
Alkanesultones (e.g., U.S. Pat. No. 3,749,695);
1,3-dicarbonyl compounds (e.g., U.S. Pat. No. 4,579,675);
Sulfates of alkoxylated alcohols or phenols (e.g., U.S. Pat. No. 3,954,639);
Cyclic lactones (e.g., U.S. Pat. Nos. 4,617,138, 4,645,515, 4,668,246, 4,963,275, and 4,971,711);
Cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Pat. Nos. 4,612,132, 4,647,390, 4,648,886, 4,670,170);
Nitrogen-containing carboxylic acids (e.g., U.S. Pat. No. 4,971,598 and British Patent No. GB 2,140,811);
Hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. Pat. No. 4,614,522);
lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460);
Cyclic carbonates or thiocarbonates, linear monocarbonates or polycarbonates, or chloroformates (e.g., U.S. Pat. Nos. 4,612,132, 4,647,390, 4,646,860, and 4,670,170);
Nitrogen-containing carboxylic acids (e.g., U.S. Pat. No. 4,971,598 and British Patent No. GB 2,440,811);
Hydroxy-protected chlorodicarbonyloxy compounds (e.g., U.S. Pat. No. 4,614,522);
lactams, thiolactams, thiolactones, or dithiolactones (e.g., U.S. Pat. Nos. 4,614,603 and 4,666,460);
Cyclic carbamates, cyclic thiocarbamates, or cyclic dithiocarbamates (e.g., U.S. Pat. Nos. 4,663,062 and 4,666,459);
Hydroxyaliphatic carboxylic acids (e.g., U.S. Pat. Nos. 4,482,464, 4,521,318, and 4,713,189);
Oxidizing agents (e.g., U.S. Pat. No. 4,379,064);
A combination of phosphorus pentasulfide and polyalkylene polyamines (e.g., U.S. Pat. No. 3,185,647);
Combinations of carboxylic acids or aldehydes or ketones and sulfur or sulfur chloride (e.g., U.S. Pat. Nos. 3,390,086 and 3,470,098);
A combination of hydrazine and carbon disulfide (e.g., U.S. Pat. No. 3,519,564);
Combinations of aldehydes and phenols (e.g., U.S. Pat. Nos. 3,649,229, 5,030,249, and 5,039,307);
Combinations of aldehydes and O-diesters of dithiophosphoric acids (e.g., U.S. Pat. No. 3,865,740);
Combinations of hydroxyaliphatic carboxylic acids and boric acid (e.g., U.S. Pat. No. 4,554,086);
A combination of hydroxyaliphatic carboxylic acids followed by formaldehyde and phenol (e.g., U.S. Pat. No. 4,636,322);
A combination of a hydroxyaliphatic carboxylic acid followed by an aliphatic dicarboxylic acid (e.g., U.S. Pat. No. 4,663,064);
A combination of formaldehyde and phenol followed by glycolic acid (e.g., U.S. Pat. No. 4,699,724);
Combinations of hydroxyaliphatic carboxylic acids or oxalic acids followed by diisocyanates (e.g., U.S. Pat. No. 4,713,191);
Combinations of inorganic acids or anhydrides of phosphorus or their partial or full sulfur analogs and boron compounds (e.g., U.S. Pat. No. 4,857,214);
A combination of an organic diacid, followed by an unsaturated fatty acid, and then a nitrosoaromatic amine, optionally followed by a boron compound, and then a glycolating agent (e.g., U.S. Pat. No. 4,973,412);
combinations of aldehydes and triazoles (e.g., U.S. Pat. No. 4,963,278);
A combination of an aldehyde and a triazole followed by a boron compound (e.g., U.S. Pat. No. 4,981,492);
and processes such as those using a combination of cyclic lactones and boron compounds (e.g., U.S. Pat. Nos. 4,963,275 and 4,971,711), which are incorporated herein by reference in their entireties.

The TBN of suitable dispersants can be from about 10 to about 65 on an oil-free basis, which corresponds to from about 5 to about 30 TBN when measured on a dispersant sample containing about 50% diluent oil.

When present, the dispersant inhibitor may be used in an amount sufficient to provide up to about 20 wt. %, based on the final weight of the lubricating oil composition. Alternative amounts of dispersant that may be used may be from about 0.1 wt. % to about 15 wt. %, or from about 0.1 wt. % to about 10 wt. %, or from about 3 wt. % to about 10 wt. %, or from about 1 wt. % to 6 wt. %, or from about 7 wt. % to about 12 wt. %, based on the final weight of the lubricating oil composition. In some embodiments, the lubricating oil composition utilizes a mixed dispersant system. A single type or a mixture of two or more types of dispersants in any desired ratio may be used.

Friction Modifiers The lubricating oil compositions herein may also optionally contain one or more friction modifiers. Suitable friction modifiers include metal-containing and metal-free friction modifiers, which may include, but are not limited to, imidazolines, amides, amines, succinimides, alkoxylated amines, alkoxylated ether amines, amine oxides, amidoamines, nitriles, betaines, quaternary amines, imines, amine salts, aminoguanidines, alkanolamides, phosphonates, metal-containing compounds, glycerol esters, sulfurized fatty compounds and olefins, sunflower oil, other naturally occurring vegetable or animal oils, dicarboxylic acid esters, esters or partial esters of polyols and one or more aliphatic or aromatic carboxylic acids, and the like.

Suitable friction modifiers may include hydrocarbyl groups selected from linear, branched, or aromatic hydrocarbyl groups, or mixtures thereof, and may be saturated or unsaturated. The hydrocarbyl groups may be composed of carbon and hydrogen or heteroatoms such as sulfur or oxygen. The hydrocarbyl groups may range from about 12 to about 25 carbon atoms. In some embodiments, the friction modifier may be a long chain fatty acid ester. In other embodiments, the long chain fatty acid ester may be a monoester, or a diester, or a (tri)glyceride. The friction modifier may be a long chain fatty amide, a long chain fatty ester, a long chain fatty epoxide derivative, or a long chain imidazoline.

Other suitable friction modifiers may include organic, ashless (metal-free), nitrogen-free organic friction modifiers. Such friction modifiers may include esters formed by reacting carboxylic acids and anhydrides with alkanols, and generally include a polar end group (e.g., carboxyl or hydroxyl) covalently bonded to an oleophilic hydrocarbon chain. An example of an organic ashless, nitrogen-free friction modifier is generally known as glycerol monooleate (GMO), which may include mono-, di-, and tri-esters of oleic acid. Other suitable friction modifiers are described in U.S. Patent No. 6,723,685, which is incorporated herein by reference in its entirety.

Amine-based friction modifiers may include amines or polyamines. Such compounds may have hydrocarbyl groups that are either linear, saturated or unsaturated, or a mixture thereof, and may contain from about 12 to about 25 carbon atoms. Further examples of suitable friction modifiers include alkoxylated amines and alkoxylated ether amines. Such compounds may have hydrocarbyl groups that are either linear, saturated, unsaturated, or a mixture thereof. They may contain from about 12 to about 25 carbon atoms. Examples include ethoxylated amines and ethoxylated ether amines.

The amines and amides can be used as such or in the form of adducts or reaction products with boron compounds such as boron oxide, boron halides, metaborates, boric acid or mono-, di- or tri-alkyl borates. Other suitable friction modifiers are described in U.S. Pat. No. 6,300,291, the entirety of which is incorporated herein by reference.

Friction modifiers may optionally be present in ranges such as from about 0% to about 10% by weight, or from about 0.01% to about 8% by weight, or from about 0.1% to about 4% by weight.

Additional Molybdenum-Containing Components The lubricating oil composition herein may also optionally contain additional molybdenum-containing compounds. The oil-soluble molybdenum compounds may have the functional properties of antiwear agents, antioxidants, friction modifiers, or mixtures thereof. The oil-soluble molybdenum compounds may include molybdenum dithiocarbamates, molybdenum dialkyl dithiophosphates, molybdenum dithiophosphinates, amine salts of molybdenum compounds, molybdenum xanthates, molybdenum thioxanthones, molybdenum sulfides, molybdenum carboxylates, molybdenum alkoxides, trinuclear organomolybdenum compounds, and/or mixtures thereof. The molybdenum sulfides include molybdenum disulfide. The molybdenum disulfide may be in the form of a stable dispersion. In one embodiment, the oil-soluble molybdenum compounds may be selected from the group consisting of molybdenum dithiocarbamates, molybdenum dialkyl dithiophosphates, amine salts of molybdenum compounds, and mixtures thereof. In one embodiment, the oil soluble molybdenum compound may be a molybdenum dithiocarbamate.

Suitable examples of molybdenum compounds that may be used include commercially available materials sold under trade names such as Molyvan 822™, Molyvan™ A, Molyvan 2000™, and Molyvan 855™ available from R. T. Vanderbilt Co., Ltd., and Sakura-Lube™ S-165, S-200, S-300, S-310G, S-525, S-600, S-700, and S-710 available from Adeka Corporation, and mixtures thereof. Suitable molybdenum components are described in US 5,650,381, US RE 37,363 E1, US RE 38,929 E1, and US RE 40,595 E1, the entireties of which are incorporated herein by reference.

Additionally, the molybdenum compound may be an acidic molybdenum compound. Included are sodium hydrogen molybdate, MoOCl4, MoO2Br2, Mo2O3Cl6, molybdenum trioxide or similar acidic molybdenum compounds, molybdic acid, ammonium molybdate, sodium molybdate, potassium molybdate, and other alkali metal molybdates and other molybdenum salts. Alternatively, the composition can be provided with molybdenum from molybdenum/sulfur complexes of basic nitrogen compounds as described, for example, in U.S. Pat. Nos. 4,263,152, 4,285,822, 4,283,295, 4,272,387, 4,265,773, 4,261,843, 4,259,195, and 4,259,194, and WO 94/06897, which are incorporated herein by reference in their entireties.

Another class of suitable organomolybdenum compounds are trinuclear molybdenum compounds and mixtures thereof, such as compounds of the formula Mo3SkLnQz, where S represents sulfur, L represents an independently selected ligand having sufficient carbon atoms in the organic group to render the compound soluble or dispersible in oil, n is 1 to 4, k is 4 to 7, Q is selected from the group of neutral electron donor compounds such as water, amines, alcohols, phosphines and ethers, and z ranges from 0 to 5, including non-stoichiometric values. There may be at least 21 total carbon atoms in the organic groups of all the ligands, such as at least 25, at least 30, or at least 35 carbon atoms. Additional suitable molybdenum compounds are described in U.S. Pat. No. 6,723,685, the entire contents of which are incorporated herein by reference.

The oil-soluble molybdenum compound contains molybdenum in an amount sufficient to provide about 0.5 ppm to about 2000 ppm, about 1 ppm to about 700 ppm, about 1 ppm to about 550 ppm, about 5 ppm to about 300 ppm, or about 20 ppm to about 250 ppm of molybdenum.

Transition metal-containing compounds In another embodiment, the oil-soluble compound may be a transition metal-containing compound or metalloid. Transition metals may include, but are not limited to, titanium, vanadium, copper, zinc, zirconium, molybdenum, tantalum, tungsten, etc. Suitable metalloids include, but are not limited to, boron, silicon, antimony, tellurium, etc.

In embodiments, the oil-soluble transition metal-containing compound can function as an anti-wear agent, a friction modifier, an antioxidant, a deposition control additive, or two or more of these functions. In embodiments, the oil-soluble transition metal-containing compound can be an oil-soluble titanium compound, such as a titanium (IV) alkoxide. Among the titanium-containing compounds that can be used in or can be used to prepare oil-soluble materials, the disclosed technology includes various Ti (IV) compounds, such as titanium (IV) oxide, titanium (IV) sulfide, titanium (IV) nitrate, titanium (IV) alkoxides, such as titanium methoxide, titanium ethoxide, titanium propoxide, titanium isopropoxide, titanium butoxide, titanium 2-ethylhexoxide, and other titanium compounds or complexes, including, but not limited to, titanium phenates, titanium (IV) 2-ethyl-1-3-hexanedioate or titanium carboxylates, such as titanium citrate or titanium oleate, and titanium (IV) (triethanolaminato) isopropoxide. Other forms of titanium encompassed by the disclosed technology include titanium phosphates, such as titanium dithiophosphates (e.g., dialkyl dithiothiophosphates) and titanium sulfonates (e.g., alkyl benzene sulfonates), or generally reaction products of titanium compounds with various acidic materials to form salts, such as oil-soluble salts. Thus, titanium compounds may be derived from organic acids, alcohols, and glycols, among others. Ti compounds may also exist in dimeric or oligomeric forms containing Ti-O-Ti structures. Such titanium materials are commercially available or can be readily prepared by suitable synthetic techniques apparent to those skilled in the art. They may exist at room temperature as solids or liquids depending on the particular compound. They may also be provided in solution form in a suitable inert solvent.

In one embodiment, titanium can be provided as a Ti-modified dispersant, such as a succinimide dispersant. Such materials can be prepared by forming a titanium mixed anhydride between a titanium alkoxide and a hydrocarbyl-substituted succinic anhydride, such as an alkenyl-(or alkyl) succinic anhydride. The resulting titanyl succinate intermediate may be used directly or may be reacted with any of a number of materials, such as (a) polyamine-based succinimide/amide dispersants having free condensable -NH functional groups, (b) components of polyamine-based succinimide/amide dispersants, i.e., alkenyl-(or alkyl) succinic anhydrides and polyamines, (c) hydroxy-containing polyester dispersants prepared by reaction of substituted succinic anhydrides with polyols, amino alcohols, polyamines, or mixtures thereof. Alternatively, the titanic succinate intermediate may be reacted with other agents such as, for example, alcohols, amino alcohols, ether alcohols, polyether alcohols or polyols, or fatty acids, and the product either used directly to impart Ti to the lubricant or further reacted with a succinic dispersant as described above. As an example, one part (mol) of tetraisopropyl titanate may be reacted with about 2 parts (mol) of polyisobutene-substituted succinic anhydride at 140-150°C for 5-6 hours to provide a titanium-modified dispersant or intermediate. The resulting material (30 g) may be further reacted with a succinimide dispersant from a polyisobutene-substituted succinic anhydride and polyethylene polyamine mixture (127 grams + diluent oil) at 150°C for 1.5 hours to produce a titanium-modified succinimide dispersant.

Another titanium-containing compound may be the reaction product of a titanium alkoxide and a _C6 - _C25 carboxylic acid. The reaction product has the following formula:
wherein n is an integer selected from 2, 3, and 4, and R is a hydrocarbyl group containing from about 5 to about 24 carbon atoms; or
wherein m+n=4, n ranges from 1 to 3, R ₄ is an alkyl moiety having from 1 to 8 carbon atoms, R ₁ is selected from hydrocarbyl groups containing from about 6 to 25 carbon atoms, and R ₂ and R ₃ are the same or different and are selected from hydrocarbyl groups containing from 1 to 6 carbon atoms, or the formula:
wherein x ranges from 0 to 3, R ₁ is selected from a hydrocarbyl group containing from about 6 to 25 carbon atoms, R ₂ and R ₃ are the same or different and are selected from a hydrocarbyl group containing from about 1 to 6 carbon atoms, and R ₄ is selected from the group consisting of H, any of the C ₆ to C ₂₅ carboxylic acid moieties.

Suitable carboxylic acids include, but are not limited to, caproic acid, caprylic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid, oleic acid, erucic acid, linoleic acid, linolenic acid, cyclohexanecarboxylic acid, phenylacetic acid, benzoic acid, neodecanoic acid, and the like.

In one embodiment, the oil-soluble titanium compound may be present in the lubricating oil composition in an amount to provide from about 0 to about 3000 ppm by weight of titanium, or from about 25 to about 1500 ppm by weight of titanium, or from about 35 ppm to about 500 ppm by weight of titanium, or from about 50 ppm to about 300 ppm.

Viscosity Index Improvers The lubricating oil compositions herein may also optionally contain one or more viscosity index improvers. Suitable viscosity index improvers may include polyolefins, olefin copolymers, ethylene/propylene copolymers, polyisobutene, hydrogenated styrene-isoprene polymers, styrene/maleic acid ester copolymers, hydrogenated styrene/butadiene copolymers, hydrogenated isoprene polymers, alpha-olefin maleic anhydride copolymers, polymethacrylates, polyacrylates, polyalkylstyrenes, hydrogenated alkenylaryl conjugated diene copolymers, or mixtures thereof. Viscosity index improvers may include star polymers, suitable examples of which are described in U.S. Publication No. 2012/0101017(A1).

The lubricating oil compositions herein may also optionally contain one or more dispersant viscosity index improvers in addition to or in place of the viscosity index improver. Suitable dispersant viscosity index improvers may include functionalized polyolefins, such as ethylene-propylene copolymers functionalized with the reaction product of an acylating agent (e.g., maleic anhydride) and an amine, amine-functionalized polymethacrylates, or esterified maleic anhydride-styrene copolymers reacted with amines.

The total amount of viscosity index improver and/or dispersant viscosity index improver may be from about 0 wt.% to about 20 wt.%, from about 0.1 wt.% to about 15 wt.%, from about 0.1 wt.% to about 12 wt.%, or from about 0.5 wt.% to about 10 wt.% of the lubricating oil composition.

Other optional additives Other additives may be selected to perform one or more functions required in the lubricating fluid. Additionally, one or more of the above additives may be multifunctional and may provide functions in addition to or other than those described herein.

Lubricating oil compositions according to the present disclosure may optionally contain other performance additives. The other performance additives may be in addition to the additives specified in this disclosure and/or may include one or more of metal deactivators, viscosity index improvers, detergents, ashless TBN boosters, friction modifiers, antiwear agents, corrosion inhibitors, rust inhibitors, dispersants, dispersant viscosity index improvers, extreme pressure agents, antioxidants, foam suppressants, demulsifiers, emulsifiers, pour point depressants, seal swell agents, and mixtures thereof. Typically, fully formulated lubricating oils contain one or more of these performance additives.

Suitable metal deactivators include benzotriazole derivatives (typically tolyltriazole), dimercaptothiadiazole derivatives, 1,2,4-triazole, benzimidazole, 2-alkyldithiobenzimidazole, or 2-alkyldithiobenzothiazole, foam suppressors including copolymers of ethyl acrylate and 2-ethylhexyl acrylate and optionally vinyl acetate, demulsifiers including trialkyl phosphates, polyethylene glycols, polyethylene oxides, polypropylene oxides, and (ethylene oxide-propylene oxide) polymers, pour point depressants including esters of maleic anhydride-styrene, polymethacrylates, polyacrylates, or polyacrylamides.

Suitable suds suppressors include silicon-based compounds such as siloxanes.

Suitable pour point depressants may include polymethyl methacrylate or mixtures thereof. The pour point depressant may be present in an amount sufficient to provide from about 0 wt. % to about 1 wt. %, from about 0.01 wt. % to about 0.5 wt. %, or from about 0.02 wt. % to about 0.04 wt. %, based on the final weight of the lubricating oil composition.

Suitable rust inhibitors may be a single compound or a mixture of compounds that have the property of inhibiting corrosion of ferrous metal surfaces. Non-limiting examples of rust inhibitors useful herein include oil-soluble high molecular weight organic acids such as 2-ethylhexanoic acid, lauric acid, myristic acid, palmitic acid, oleic acid, linoleic acid, linolenic acid, behenic acid, and cerotic acid, as well as oil-soluble polycarboxylic acids including tall oil fatty acids, dimer and trimer acids produced from oleic and linoleic acids. Other suitable corrosion inhibitors include long chain alpha, omega-dicarboxylic acids in the molecular weight range of about 600 to about 3000, and alkenyl succinic acids in which the alkenyl group contains about 10 or more carbon atoms, such as tetrapropenyl succinic acid, tetradecenyl succinic acid, and hexadecenyl succinic acid. Another useful type of acidic corrosion inhibitor is the half ester of an alkenyl succinic acid having about 8 to about 24 carbon atoms in the alkenyl group with an alcohol, such as a polyglycol. The corresponding half amides of such alkenyl succinic acids are also useful. Useful rust inhibitors are high molecular weight organic acids. In some embodiments, the engine oil does not contain a rust inhibitor.

When present, the rust inhibitor may be used in an amount sufficient to provide from about 0 wt. % to about 5 wt. %, from about 0.01 wt. % to about 3 wt. %, from about 0.1 wt. % to about 2 wt. %, based on the final weight of the lubricating oil composition.

Generally speaking, suitable lubricants may contain additive components in the ranges listed in the table below.

The percentages of each component above represent the weight percent of each component based on the weight of the final lubricating oil composition. The remainder of the lubricating oil composition consists of one or more base oils.

The additives used in formulating the compositions described herein may be blended into the base oil individually or in various subcombinations. However, it may be preferred to use an additive concentrate (i.e., additives plus a diluent such as a hydrocarbon solvent) and mix all of the components simultaneously.

The following examples are illustrative, but not limiting, of the methods and compositions of the present disclosure. Other suitable modifications and adjustments of the various conditions and parameters normally employed in the art will be known to those skilled in the art without departing from the spirit and scope of the present disclosure. All patents and publications cited herein are hereby fully incorporated by reference in their entirety.

A series of tests was conducted to determine the effect of calcium and magnesium detergents and the contribution of ash content to diesel particulate filter clogging and low speed pre-ignition events.

Each of the lubricating oil compositions contained a major amount of base oil and a base conventional dispersant inhibitor (DI) package. The DI package contained conventional amounts of dispersants, antiwear additives, antioxidants, friction modifiers, antifoam agents, process oils, viscosity index improvers, and pour point depressants, as provided in Table 3 below. Specifically, the DI package contained succinimide dispersants, molybdenum-containing compounds, antioxidants, and antifoam agents. The majority of the base oils were a mixture of Group III and Group IV base oils. The components that were modified are specified in the example tables and discussion below. All values listed are stated as weight percent of the component in the lubricating oil composition (i.e., active stock plus diluent oil, if any) unless otherwise specified.

The sulfated ash (SASH) was calculated for the total metal elements contributing to the SASH in the lubricant composition according to the following factors multiplied by the amount of each metal element in the lubricant composition according to http://konnaris.com/portals/0/search/calculation.htm:

The VW PV 1485 test is a diesel particulate filter test used to measure the clogging tendency of diesel particulate filters. The diesel particulate filter test is performed on a VW 1.9 liter, 4-cylinder turbocharged direct injection diesel engine. One complete test includes six test cycles. The first five stages are performed to condition the engine and the last stage implements a 144 hour ash load.

Improvements in reducing clogging in diesel particulate filters are observed when delta pressure (ΔP) vs. oil consumption (OC) is 0.6 kPa/kg or less. Further improvements in clogging are observed when ΔP vs. OC is 0.5 kPa/kg or less, and even further improvements in clogging are observed when ΔP vs. OC is 0.45 kPa/kg or less.

Baseline oil R-1 was formulated with about 80.7 wt. % Group III base oil, 12.1 wt. % HiTEC® 11150 PCMO additive package available from Afton Chemical Corporation, and 7.2 wt. % 35 SSI ethylene/propylene copolymer viscosity index improver. The HiTEC® 11150 passenger car motor oil additive package is an API SN, ILSAC-GF-5, and ACEA A5/B5 certified DI package. R-1 also exhibited the following properties and partial elemental analysis:

The following example evaluated the performance of a VW DPF.

The results shown in Examples 2 and 3 of the present invention show that when the level of sulfate ash content is held constant, a lower ratio of total Ca ppm from the detergent to total Mg ppm from the detergent provides a reduction in clogging.

Furthermore, the results shown in Table 4 indicate that the VW PV 1485 test does not limit the formulation to 0.6% sulfate ash, since Examples 2 and 3 of the present invention pass the VW PV 1485 test at a sulfate ash content of 0.8%.

Low speed pre-ignition (LSPI) events were measured in a GM 2.0 liter, 4-cylinder Ecotec turbocharged gasoline direct injection (TGDi) engine. One complete LSPI combustion engine test consisted of four test cycles. Within a single test cycle, two operating phases or segments are repeated to generate an LSPI event. In phase A, when LSPI is most likely to occur, the engine operates at about 2000 rpm and about 1800 kPa brake mean effective pressure (BMEP). In phase B, when LSPI is least likely to occur, the engine operates at about 1500 rpm and about 1700 kPa BMEP. For each phase, data is collected over 25,000 engine cycles. The test cycle structure is as follows: Phase A-Phase A-Phase B-Phase B-Phase A-Phase A. Each phase is separated by an idle period. Because LSPI is statistically significant during Stage A, the LSPI event data considered in this example included only LSPI events that occurred during Stage A operation. Thus, for one complete LSPI combustion engine test, data typically occurred over a total of 16 stages and were used to evaluate the performance of the comparative oils and the oils of the present invention.

LSPI events were determined by monitoring peak cylinder pressure (P P ) and when 2% of the combustible material in the combustion chamber is burned (MFB02). Peak cylinder pressure thresholds were calculated for each cylinder and each stage, typically ranging from 6,500 to 8,500 kPa. MFB02 thresholds were calculated for each cylinder and each stage, typically ranging from about 3.0 to about 7.5 crank angles (CAD) after top dead center (ATDC). LSPI was recorded when both PP and MFB02 thresholds were exceeded in a single engine cycle. LSPI events can be reported in a number of ways. To remove any ambiguity associated with reporting numbers per engine cycle, where different combustion engine tests may be performed with different numbers of engine cycles, the relative number of LSPI events for the comparative oil and the oil of the present invention was reported as an "LSPI ratio." In this way, improvements over some standard response are clearly demonstrated.

In the following examples, the LSPI ratio is reported as the ratio of the LSPI events of the test oil to the LSPI events of the reference oil "R-1."

A significant improvement in LSPI is observed when the reduction in LSPI events is more than 50% (LSPI ratio less than 0.5) relative to the reference oil R-1. A further improvement in LSPI is observed when the reduction in LSPI events is more than 70% (LSPI ratio less than 0.3), an even further improvement in LSPI is observed when the reduction in LSPI events is more than 75% (LSPI ratio less than 0.25), an even further improvement in LSPI is observed when the reduction in LSPI events is more than 80% relative to R-1 (LSPI ratio less than 0.20), and an even further improvement in LSPI is observed when the reduction in LSPI events is more than 90% relative to R-1 (LSPI ratio less than 0.1). Therefore, the LSPI ratio for the R-1 reference oil is considered to be 1.00.

In the following examples, LSPI ratios are reported as the ratio of the LSPI events of the test oil to the LSPI events of the reference oil "R-1."

The preceding examples show that various lubricant formulations of the present invention can provide significant reductions in LSPI events. Additionally, Example 1 demonstrates that the lubricant of the present invention can pass diesel particulate clogging tests and significantly reduce LSPI events. This may be particularly useful in boosted spark ignition combustion engines equipped with diesel particulate filters.

Other embodiments of the present disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the embodiments disclosed herein. As used throughout the specification and claims, "a" and/or "an" may refer to one or more than one. Unless otherwise indicated, all numbers expressing properties such as amounts of ingredients, molecular weights, percentages, ratios, reaction conditions, and the like used in the specification and claims, whether or not the term "about" is present, should be understood in all instances as being modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should be construed at least by the number of reported significant digits and applying ordinary rounding techniques. Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the disclosure are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical values, however, inherently contain certain errors necessarily resulting from the standard deviation found in their respective testing measurements. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

The foregoing embodiments are subject to considerable variation in practice. Accordingly, the embodiments are not limited to the specific exemplifications set forth above. Rather, the above-described embodiments are within the spirit and scope of the appended claims, including the equivalents thereof available at law.

The patentee does not intend to open to the public any disclosed embodiments, and to the extent any disclosed modifications or variations do not literally fall within the scope of the claims, they are considered part of them under the doctrine of equivalents.

It is to be understood that each component, compound, substituent, or parameter disclosed herein should be construed as disclosed for use alone or in combination with one or more of any and all other components, compounds, substituents, or parameters disclosed herein.

Each amount/value or amount/value range for each component, compound, substituent, or parameter disclosed herein should be construed as disclosed in combination with each amount/value or amount/value range disclosed for any other component, compound, substituent, or parameter disclosed herein, and any combination of amount/values or amount/value ranges for two or more components, compounds, substituents, or parameters disclosed herein should also be understood to be disclosed in combination with each other for purposes of this description.

It is further understood that each range disclosed herein should be construed as a disclosure of each specific value within the disclosed range having the same number of significant digits. Thus, a range of 1 to 4 should be construed as an explicit disclosure of the values 1, 2, 3, and 4.

It is further understood that each lower limit of each range disclosed herein should be construed as disclosed in combination with each upper limit of each range and each specific value within each range for the same component, compound, substituent, or parameter. Thus, the present disclosure should be construed as a disclosure of all ranges derived by combining each lower limit of each range with each upper limit of each range, or with each specific value within each range, or by combining each upper limit of each range with each specific value within each range.

Furthermore, a specific amount/value of a component, compound, substituent, or parameter disclosed in the description or examples should be construed as a disclosure of either a lower or upper limit of a range and thus can be combined with any other lower or upper limit of a range or specific amount/value for the same component, compound, substituent, or parameter disclosed elsewhere in this application to form a range for that component, compound, substituent, or parameter.

Claims (14)

1. A lubricating oil composition comprising:
a) greater than 50 wt. %, based on the total weight of the lubricating oil composition, of a base oil of lubricating viscosity;
b) a cleaning agent comprising the following components i) and ii):
i) one or more overbased calcium-containing detergents having a total base number of at least 150 mg KOH/g and excluding calcium salicylate detergents;
ii) one or more overbased magnesium-containing detergents having a total base number greater than 225 mg KOH/g;
c) one or more molybdenum-containing compounds ;
d ) 700 ppm to 900 ppm phosphorus, based on the total weight of the lubricating oil composition;
e ) a total measured sulfated ash content of 0.8 wt. % or less, based on the total weight of the lubricating oil composition, as measured by ASTM D874;
a) the concentration of calcium in the lubricating oil composition is greater than 1350 ppm and less than 1700 ppm based on the total weight of the lubricating oil composition;
b) the concentration of magnesium in the lubricating oil composition is 15 ppm or less based on the total weight of the lubricating oil composition;
C) the concentration of molybdenum in the lubricating oil composition is greater than 100 ppm and less than 450 ppm based on the total weight of the lubricating oil composition;
d) the concentration of boron in the lubricating oil composition is from 0 ppm to less than 10 ppm based on the total weight of the lubricating oil composition;
e) the ratio of calcium to magnesium in the lubricating oil composition is 3.5 or greater in ppm; and
A lubricating oil composition, wherein the lubricating oil composition provides a diesel particulate filter delta pressure (ΔP) versus oil consumption result of less than 0.43 kPa/kg after 144 hours, as measured in a VW PV 1485 test. 2. The lubricating oil composition of claim 1, wherein the one or more overbased calcium- containing detergents have a total base number of greater than 225 mg KOH/g as measured by the method of ASTM D-2896. The lubricating oil composition of any one of claims 1 to 2, wherein the one or more overbased calcium- containing detergents have a total base number of greater than 250 mg KOH/g as measured by the method of ASTM D-2896. The lubricating oil composition of any one of claims 1 to 3, wherein the concentration of calcium in the lubricating oil composition is less than 1670 ppm, based on the total weight of the lubricating oil composition. The lubricating oil composition of any one of claims 1 to 4, wherein the concentration of calcium in the lubricating oil composition is less than 1500 ppm, based on the total weight of the lubricating oil composition. The lubricating oil composition of any one of claims 1 to 5, wherein the total sulfated ash content in the lubricating oil composition is greater than 0.6 wt.% as measured by ASTM D874. The lubricating oil composition of any one of claims 1 to 6, wherein the one or more overbased magnesium-containing detergents have a total base number of greater than 225 mg KOH/g as measured by the method of ASTM D-2896. The lubricating oil composition of any one of claims 1 to 7, wherein the one or more overbased magnesium-containing detergents have a total base number of greater than 300 mg KOH/g as measured by the method of ASTM D-2896. The lubricating oil composition of any one of claims 1 to 8, wherein the one or more overbased magnesium-containing detergents have a total base number of greater than 350 mg KOH/g as measured by the method of ASTM D-2896. The lubricating oil composition of any one of claims 1 to 9 , wherein the concentration of boron in the lubricating oil composition is 0 ppm, based on the total weight of the lubricating oil composition. 10. The lubricating oil composition of any one of claims 1 to 9 , wherein the lubricating oil composition has greater than 0 ppm boron and the ratio of total metals in ppm in the lubricating oil composition to total boron in ppm in the lubricating oil composition is greater than 7.5. The lubricating oil composition of any one of claims 1 to 11 , wherein the one or more overbased magnesium- containing detergents have a total base number of greater than 400 mg KOH/g as measured by the method of ASTM D-2896. The lubricating oil composition according to any one of claims 1 to 12 , wherein the lubricating oil composition is an engine oil composition. operating an engine equipped with a diesel particulate filter and lubricated with the lubricating oil composition of any one of claims 1 to 13 ;
1. A method for reducing plugging in a diesel particulate filter, wherein the lubricating oil composition comprises a total measured sulfated ash content of 0.5 wt.% or greater, as measured by ASTM D874, based on the total weight of the lubricating oil composition.