Engine oil composition

Abstract

The present invention provides an engine oil composition comprising: i) a base oil in the range of 70% to 95% by weight based on the total weight of the engine oil composition; ii) a dispersant comb polymer in the range of 0.01% to 15% by weight based on the total weight of the engine oil composition; wherein the dispersant comb polymer comprises: a. 13.7% by weight of a macromonomer, which is an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with a Mn of 4750 g / mol; b. 51. c. 5% by weight of n-butyl methacrylate; d. 17.3% by weight of LMA; e. 11.2% by weight of styrene; f. 0.2% by weight of methyl methacrylate; and f. 6.1% by weight of N,N-dimethylaminoethyl methacrylate; wherein, based on the total weight of the modified dispersant inhibitor additive package, the modified dispersant inhibitor package contains 30% by weight or less of a succinimide-type dispersant, and wherein the engine oil composition has an SAE viscosity grade of 0W-X, where X is 30 or less.

Description

Technical Field

[0001] This invention relates to engine oil compositions, and more particularly to engine oil compositions that provide improved fuel economy. Background Technology

[0002] Engine oil formulation is typically a balance between the positive effects of certain additives and base oils and their limitations. There is a persistent need to improve fuel economy in all types of vehicles, and some solutions to this can be found in improving the engine oils used.

[0003] Generally speaking, lower viscosity engine oils lead to improved fuel economy. However, while maintaining a suitable lubricant film thickness, there is a possibility that the reduction in viscosity has its limits. Without a suitable lubricant film thickness, increased wear will occur, leading to material fatigue and ultimately a shorter service life for the machine.

[0004] Increasing the viscosity index (VI) of a lubricant can lead to improved fuel economy. The VI of a lubricant is a method for measuring the temperature dependence of its viscosity. A high viscosity index indicates a lower temperature dependence of viscosity changes. At a given temperature and constant viscosity, an increase in the viscosity index means that the viscosity at lower temperatures is lower than that of a comparable lubricant with a lower viscosity index.

[0005] Another important parameter for engine oil is its high-temperature high-shear (HTHS) viscosity. HTHS viscosity indicates the viscosity of engine oil under harsh engine operating conditions, such as high engine speeds or shear rates and high temperatures. It gives the temporary viscosity loss of the lubricant under high shear and elevated temperature conditions representative of typical engine operation. The lower the HTHS viscosity of the oil, the higher the expected fuel economy. The ASTM D4683 standard HTHS viscosity is determined using a tapered bearing simulator at a high temperature of 150°C and 1.10... 6 s –1 The viscosity is measured at the shear rate. The test method ASTM D6616 also measures HTHS viscosity, but at the lower temperatures of 100°C and 80°C, it is more representative of bearing conditions in automotive engines operating within that temperature range.

[0006] The reduced viscosity grade of engine oil according to the J300 specification results in lower kinematic viscosity (KV) at 100°C (measured at low shear rates) and lower HTHS viscosity at 150°C. While this is beneficial for fuel economy, failure to control HTHS at 150°C can lead to poorer engine protection, resulting in shortened engine life and ongoing damage.

[0007] Viscosity index improvers (VII), also known as viscosity modifiers (VMs), are well known in the art for increasing fluid viscosity at high temperatures. Typical VMs include olefin copolymer types, polymethyl methacrylates, styrene-hydrogenated diene blocks, and star polymers, and are referred to as conventional VMs. Some viscosity index improvers have been specifically designed to provide the necessary HTHS 150°C performance required for engine protection at high temperatures and high shear rates, while maintaining low or even zero viscosity increase at intermediate temperatures such as 80°C, 60°C, and 40°C. Comb-shaped viscosity index improvers comprising a polymethyl methacrylate backbone with substituted and / or unsubstituted side chains have been described in the prior art and, for the same HTHS 150°C performance according to ASTM D4683, provide lower HTHS viscosity values ​​at 80°C and 100°C temperatures according to ASTM 6616 at the same ASTM D4683. The relatively low values ​​of HTHS 80 and HTHS 100 for the same HTHS 150 performance are key indicators of improved fuel economy performance.

[0008] Functionalized comb polymers (such as those described in US20160097017, US20110306533, US20100190671, US20080194443, and US5597871) can be used to provide one or more additional functionalities as well as viscosity index improvements. This can reduce the need for additional additives in lubricant formulations or to enhance certain performance properties, such as sludge or deposit control.

[0009] Typical engine oil formulations include a dispersant inhibitor (DI) package containing ashless dispersants. The active component of a DI package typically comprises approximately 50% to 60% by weight of ashless dispersants, with the balance consisting of other ingredients such as detergents, anti-wear agents, antioxidants, and various other trace additives. An example of a typical composition of a DI package is given in US5512192. Ashless dispersants are included to prevent varnish or sludge from depositing on the working surfaces of the engine. While this protection is desirable in engine oils, typical ashless dispersants are considered particularly “heavy.” That is, they exhibit low viscosity characteristics and do not decrease in viscosity at high shear rates or temporarily thin under shear. Therefore, such dispersants may impair fuel economy improvements. Generally, fuel economy deteriorates as the rate of dispersant treatment in the engine oil formulation increases.

[0010] The object of this invention is to provide an engine oil composition that has improved fuel economy performance under a wide range of operating conditions. Attached Figure Description

[0011] Figures 1 to 2 This is a graph illustrating the results of the embodiments included herein. Summary of the Invention

[0012] This invention provides an engine oil composition comprising:

[0013] i) Base oil in the range of 70% to 95% by weight, based on the total weight of the engine oil composition;

[0014] ii) Dispersant comb polymer in the range of 0.01% to 15% by weight based on the total weight of the engine oil composition;

[0015] iii) A package of modified dispersant inhibitor additives ranging from 4.99% to 15% by weight, based on the total weight of the engine oil composition.

[0016] The dispersant comb polymer consists of the following components:

[0017] a. 13.7% by weight of macromonomer, which is an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol;

[0018] b. 51.5% by weight of n-butyl methacrylate;

[0019] c. 17.3% by weight of LMA;

[0020] d.11.2% by weight of styrene;

[0021] e. 0.2% by weight of methyl methacrylate; and

[0022] f. 6.1% by weight of N,N-dimethylaminoethyl methacrylate;

[0023] Based on the total weight of the modified dispersant inhibitor additive package, the modified dispersant inhibitor package contains 30% by weight or less of a succinimidyl dispersant, and

[0024] The engine oil composition has an SAE viscosity grade of 0W-X, where X is 30 or less.

[0025] The present invention also provides the use of such an engine oil composition in an engine crankcase to reduce motor drive friction torque.

[0026] The present invention further provides the use of such engine oil compositions in the engine crankcase to improve fuel economy and viscosity characteristics. Detailed Implementation

[0027] The inventors have surprisingly discovered that engine oil compositions comprising a specific dispersant comb polymer combined with a modified dispersant inhibitor (DI) package having reduced ashless dispersant treatment provide improved fuel economy characteristics. These engine oil compositions have been shown to result in reduced motor-driven friction torque in motor-driven friction engine tests, increased viscosity index, and improved viscosity characteristics at low temperatures (HTHS100, HTHS80, and KV 40°C), all indicating improved fuel economy over the operating temperature range.

[0028] The engine oil composition of the present invention comprises a base oil, a specific dispersant comb polymer, and a modified DI package.

[0029] The base oil can be a single base oil or a blend of suitable base oils. Preferably, the base oil comprises one or more Fischer-Tropsch derived base oils. The term "Fischer-Tropsch derived" means that the base oil is or is derived from a synthetic product synthesized by the Fischer-Tropsch process. Fischer-Tropsch derived base oils may also be referred to as XTL (X to liquid) base oils. In the term "XTL," X represents the source of carbon atoms, such as gas to liquid (GTL) or biomass to liquid (BTL).

[0030] Suitable Fischer-Tropsch-derived base oils that can be readily used as base oils in the lubricating compositions of the present invention are, for example, those Fischer-Tropsch-derived base oils disclosed in EP0776959, EP0668342, WO9721788, WO0015736, WO0014188, WO0014187, WO0014183, WO0014179, WO0008115, WO9941332, EP1029029, WO0118156 and WO0157166.

[0031] The term “Fischer-Tropsch-derived base oil” as used in this article refers to a single base oil or a blend of base oils.

[0032] Typically, the kinematic viscosity of Fischer-Tropsch derived base oils at 100°C (as measured by ASTM D445) is within 1 mm. 2 / s(cSt) to 30mm 2 / s(cSt), preferably 1mm 2 / s(cSt) to 25mm 2 / s(cSt), and more preferably 2mm 2 / s to 12mm 2 Within the range of / s. Preferably, the Fischer-Tropsch derived base oil has a kinematic viscosity (as measured by ASTM D445) of at least 2.5 mm at 100°C. 2 / s, more preferably at least 3.0mm 2 / s.

[0033] In one embodiment of the invention, the Fischer-Tropsch derived base oil comprises a kinematic viscosity of at most 5.0 mm at 100°C. 2 / s, preferably up to 4.5mm 2 / s, more preferably up to 4.2mm 2 / s of Fischer-Tropsch base oil (e.g., "GTL 4"). In another embodiment of the invention, the Fischer-Tropsch derived base oil comprises a kinematic viscosity of at most 8.5 mm at 100°C. 2 / s, preferably up to 8mm 2 / s of Fischer-Tropsch base oil (e.g., "GTL 8"). In another embodiment of the invention, the Fischer-Tropsch derived base oil comprises a kinematic viscosity of at most 3.0 mm at 100°C. 2 / s, preferably up to 2.8mm 2 / s of Fischer-Tropsch base oil (e.g., "GTL 3").

[0034] In addition, the kinematic viscosity of Fischer-Tropsch derived base oils at 40°C (as measured by ASTM D445) is typically 8 mm. 2 / s(cSt) to 100mm 2 / s(cSt), preferably 10mm 2 / s to 50mm 2 / s.

[0035] The Fischer-Tropsch-derived base oil preferably has a viscosity index in the range of 100 to 200 (according to ASTM D2270). Preferably, the viscosity index of the Fischer-Tropsch-derived base oil is at least 125, preferably 130. It is also preferred that the viscosity index is below 180, preferably below 150.

[0036] When the Fischer-Tropsch-derived base oil comprises a blend of two or more Fischer-Tropsch-derived base oils, the above values ​​apply to the blend of two or more Fischer-Tropsch-derived base oils.

[0037] In a proposed embodiment of the invention where the base oil is a Fischer-Tropsch derived base oil, the base oil preferably contains 80% by weight or more of a Fischer-Tropsch derived base oil based on the total weight of the base oil. However, in addition to Fischer-Tropsch derived base oils, the engine oil composition may also contain one or more other base oils. There are no particular limitations on other base oils used in the engine oil compositions according to the invention, and a variety of conventional mineral oils, synthetic oils, and naturally derived esters such as vegetable oils can be readily used. Any base oil belonging to Group I, Group II, Group III, Group IV, Group V, etc. of the API (American Petroleum Institute) base oil categories can be readily used, provided that the requirements for the engine oil composition according to this disclosure are met. Furthermore, the base oil may conveniently comprise a mixture of one or more mineral oils and / or one or more synthetic oils; therefore, the term "base oil" may refer to a mixture containing more than one base oil.

[0038] The total amount of base oil incorporated into the engine oil composition is in the range of 65% to 95% by weight relative to the total weight of the lubricant composition, more preferably in the range of 65% to 90% by weight, and most preferably in the range of 75% to 88% by weight.

[0039] The dispersant comb polymer used in this invention consists of the following:

[0040] a. 13.7% by weight of macromonomer, which is an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol;

[0041] b. 51.5% by weight of n-butyl methacrylate;

[0042] c. 17.3% by weight of LMA;

[0043] d.11.2% by weight of styrene;

[0044] e. 0.2% by weight of methyl methacrylate; and

[0045] f.6.1% by weight of N,N-dimethylaminoethyl methacrylate.

[0046] Appropriately, the weight-average molecular weight of the dispersant comb polymer is 560,000 g / mol.

[0047] Modified DI packages contain at least antioxidant additives, anti-wear additives, and detergent additives. They may also contain additional additives such as friction modifiers, pour point depressants, corrosion inhibitors, defoamers, and sealing fixatives or sealing compatibilizers.

[0048] The detergent additive is suitably a metal-containing detergent that includes calcium and / or magnesium as alkaline earth metals. The content of the metal-containing detergent, relative to the total amount of the engine oil composition, is preferably from 0.05% to 20% by weight, more preferably from 1.0% to 10.0% by weight, and even more preferably from 2.0% to 5.0% by weight, based on the alkaline earth metal content.

[0049] Metal-containing detergents preferably contain salicylates and / or phenolates and / or carboxylates and / or sulfonates as major components.

[0050] The anti-wear additive in the modified DI package is suitably zinc dialkyl dithiophosphate. Based on the total weight of the engine oil composition, the content of zinc dialkyl dithiophosphate is preferably from 0.05% to 1.5% by weight, and more preferably from 0.4% to 1.4% by weight. Additional or alternative anti-wear additives can be readily used in the compositions of the present invention.

[0051] The antioxidant in the modified DI package is suitably a mixture of one or more phenolic antioxidants and one or more amine antioxidants. Based on the total weight of the engine oil composition, the antioxidant content is preferably from 0.1% to 5.0% by weight, more preferably from 0.3% to 3.0% by weight, and most preferably from 0.5% to 1.5% by weight.

[0052] Other non-comb-shaped polymethacrylates can be conveniently used as effective pour point depressants in the lubricating oil compositions of the present invention.

[0053] Organic molybdenum compounds, such as molybdenum dialkyl dithiocarbamate (MoDTC), can be conveniently used as friction modifiers in the lubricating oil compositions of the present invention.

[0054] In addition, compounds such as alkenyl succinic acid or its ester moiety, benzotriazole-based compounds, and thiadiazole-based compounds can be conveniently used as corrosion inhibitors in the engine oil compositions of the present invention.

[0055] Compounds such as polysiloxanes, dimethyl polycyclohexane, and polyacrylates can be conveniently used as defoamers in the engine oil compositions of the present invention.

[0056] Compounds that can be conveniently used as sealing fixatives or sealing compatibilizers in the engine oil compositions of the present invention include, for example, commercially available aromatic esters.

[0057] Optionally, the modified DI package contains a succinimide-type dispersant. An advantage of this invention is that the amount of succinimide-type dispersant present in the DI package can be significantly reduced compared to the amount used in typical engine oil packages, where a viscosity modifier is used that is not a dispersant comb polymer consisting of: 13.7 wt% of a macromonomer (an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with a Mn of 4750 g / mol); 51.5 wt% of n-butyl methacrylate; 17.3 wt% of LMA; 11.2 wt% of styrene; 0.2 wt% of methyl methacrylate; and 6.1 wt% of N,N-dimethylaminoethyl methacrylate.

[0058] A typical industrial-standard DI additive package will contain at least 35% by weight of a succinimide-type dispersant compound. Based on the total weight of the modified DI additive package, the modified DI package of the present invention contains 30% by weight or less of a succinimide-type dispersant. In embodiments of the present invention, based on the total weight of the modified DI additive package, the modified DI additive package may contain no more than 25% by weight, no more than 20% by weight, or less of a succinimide-type dispersant.

[0059] Based on the total weight of the engine oil composition, a typical engine oil composition will contain at least 4% by weight of a succinimide-type dispersant. In this invention, based on the total weight of the engine oil composition, the succinimide-type dispersant is preferably present in an amount not exceeding 3.5% by weight, more preferably not exceeding 3.2% by weight.

[0060] If the engine oil composition of the present invention contains a succinimide-type dispersant, then the succinimide-type dispersant is preferably present in an amount of at least 0.01% by weight based on the total weight of the engine oil composition.

[0061] Preferably, the amount of succinimide-type dispersant present in the modified dispersant inhibitor package is at least 50% lower than the amount present when using the following viscosity modifier, which is not a dispersant comb polymer composed of: 13.7 wt% of a macromonomer (an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol); 51.5 wt% of n-butyl methacrylate; 17.3 wt% of LMA; 11.2 wt% of styrene; 0.2 wt% of methyl methacrylate; and 6.1 wt% of N,N-dimethylaminoethyl methacrylate.

[0062] If present, the ashless dispersant is suitably selected from the group consisting of: boronized or non-boronized alkyl succinimide or alkenyl succinimide, boronized or non-boronized alkyl succinate or alkenyl succinate, boronized or non-boronized alkyl succinicimide or alkenyl succinicimide, boronized or non-boronized alkyl succinic amide or alkenyl succinic amide, or any combination thereof.

[0063] Examples of ashless succinic imide dispersants and boron-modified ashless succinic imide dispersants include the substances listed below. Examples of succinic imide dispersants include nitrogen-containing compounds, such as alkenyl- or alkyl-containing succinic imides derived from polyolefins, benzylamines, polyamines, and Mannich bases. Additionally, succinic imide dispersants can be derivatives obtained by acting phosphorus compounds such as thiophosphate or thiophosphate esters, organic acids, hydroxyl polyoxyalkylene carbonates, etc., on these nitrogen-containing compounds. Examples of boron-modified ashless succinic imide dispersants include derivatives obtained by acting boron compounds such as boric acid or borates on these nitrogen-containing compounds.

[0064] The dispersant in this embodiment may be a single dispersant, or a combination of two or more types thereof, selected arbitrarily from those listed above. Furthermore, the ashless dispersant is particularly preferably a di-polybutenyl succinicotinamide, a derivative of di-polybutenyl succinicotinamide, or a mixture thereof.

[0065] Here, the alkenyl and alkyl groups mentioned above can be straight-chain or branched. Specifically, the alkenyl and alkyl groups are alkenyl and alkyl groups derived from oligomers of olefins such as propylene, 1-butene, and isobutene, as well as co-oligomers of ethylene and propylene. The branched alkyl and branched alkenyl groups are preferably derived from polyisobutylene, which is a type of polybutene with a number average molecular weight of 500 to 5000, more preferably 700 to 4000, and even more preferably 900 to 3000. The molecular weight of the polymer additive can be obtained, for example, by using a Shodex GPC-101 high-performance liquid chromatography system manufactured by Showa Denko Kabushiki Kaisha, setting the temperature to 40°C, using a differential refractive index (RI) detector as the detector, using THF as the carrier gas at a flow rate of 1.0 ml / min (reference 0.3 ml / min), setting the sample injection volume to 100 μL, using a combination of {KF-G (Shodex)×1 and KF-805L (Shodex×2)} as the column, using the range corresponding to the peak molecular weight, and calculating the average molecular weight (weight-average molecular weight and number-average molecular weight for polystyrene).

[0066] The weight-average molecular weight of the ashless dispersant is preferably from 1,000 to 20,000, more preferably from 1,500 to 10,000, and even more preferably from 5,000 to 10,000.

[0067] Typically, modified DI packages will also contain a suitable carrier fluid. Antioxidant additives, anti-wear additives, detergent additives, and succinimide-based dispersants (if present), along with any other additives, are dispersed in the carrier fluid before being added to the base oil. The carrier fluid is typically a base oil, such as a Group 1 mineral oil.

[0068] The engine oil composition of the present invention has an SAE viscosity grade of 0W-X, wherein X is 30 or less. Suitably, X can be 30, 20, 12, 8 or 4. Preferably, X is 20 or less.

[0069] To facilitate a better understanding of the present invention, the following embodiments of certain aspects of some implementation schemes are provided. In no way should the following embodiments be construed as limiting or restricting the entire scope of the invention.

[0070] Example

[0071] Example 1

[0072] Fully formulated engine oils according to Table 1, with a blend viscosity grade of SAE 0W-20. The amounts of components are given as % by weight based on the total weight of the composition.

[0073] The components used are as follows:

[0074] GTL 4 is a Fischer-Tropsch-derived base oil with a kinematic viscosity (ASTM D445) of approximately 4 cSt at 100°C, which can be conveniently prepared by the method described in WO02070631.

[0075] Full DI Pack 1 - Full SAPS Additive Pack contains anti-wear additives, detergents, non-succinimid dispersants and antioxidants, plus a polyisobutylene succinimid dispersant, which is present in an amount of 5.5% by weight of the dispersant based on the entire engine oil composition.

[0076] Modified DI Package 1 - The same additive package as Full DI Package 1, except that it does not contain polyisobutylene dispersant.

[0077] Modified DI Pack 2 - is the same additive pack as Full DI Pack 1, except that it contains a polyisobutylene succinimide dispersant, which is present in an amount of 2.75% by weight of the dispersant based on the entire engine oil composition.

[0078] Viscoplex 3-201 viscosity modifier is available from Evonik.

[0079] Dispersant comb polymer - a dispersant comb polymer composed of the following: 13.7 wt% macromonomer (an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol); 51.5 wt% n-butyl methacrylate; 17.3 wt% LMA; 11.2 wt% styrene; 0.2 wt% methyl methacrylate; and 6.1 wt% N,N-dimethylaminoethyl methacrylate.

[0080] Viscoplex 1-180-polyalkyl methacrylate pour point depressant is commercially available from Evonik.

[0081] Table 1

[0082]

[0083] Rheological properties are tested using the following industry standard tests: kinematic viscosity (cSt) at 100°C and 40°C, and viscosity index (VI) as measured by ASTM D445. HTHS150 is the high-temperature high-shear viscosity at 150°C, measured by ASTM D4683, in centipoises (cP). HTHS100 and HTHS80 are the high-temperature high-shear viscosities at 100°C and 80°C, respectively, measured by ASTM D6616, in centipoises (cP).

[0084] The heat pipe test is a laboratory screening test developed to simulate high-temperature piston deposit formation in the ASTM Sequence IIIG engine test and to grade oils for those with a tendency to exacerbate piston deposit formation. In the ASTM Sequence IIIG engine test, the heat pipe deposit test provides a good correlation with gasoline piston deposit formation. In this test, vacuum suction draws oil from a small-volume reservoir maintained at 150°C into a hot glass tube heated to 275°C. Oil is drawn into the tube every 60 seconds, with a residence time of 2–3 seconds, for a cycle of 6 hours. This action creates conditions for the oxidation of a thin oil film inside the heat pipe and the formation of deposits. At the end of the 6 hours, an optical “in-situ” deposit quality rating is assigned to the tube on a scale of 10 to 1, following the Sequence IIIG grading procedure. A rating of 10 indicates a clean tube with no deposit formation, while a rating of 1 indicates excessive deposit formation.

[0085] The results of all these measurements are given in Table 2.

[0086] Table 2

[0087] Benchmark 1 Test oil 1 Test oil 2 KV40℃ <![CDATA[mm 2 / s]]> 33.3 25.4 28.1 KV100℃ <![CDATA[mm 2 / s]]> 7.6 7.0 6.84 VI 208 263 218 HTHS 150℃ mPas 2.62 2.63 2.64 HTHS 100℃ mPas 5.37 4.33 4.71 HTHS 80℃ mPas 7.95 6.38 6.99 Heat pipe quality [275℃, 6 hours] 9.6 6.6 9.0

[0088] These results show improved viscosity index (VI) of the candidate oils compared to the reference oil. While all oils were thickened to the same HTHS 150, the candidate oil containing the dispersant comb polymer showed improved HTHS 100 and HTHS 80 values ​​compared to the reference formulation blended with commercially available nonfunctionalized COMB VM VP 3-201. This example demonstrates that engine oils containing the dispersant comb polymer and reduced levels of dispersant provide improved low-temperature viscosity and viscosity index compared to reference oils containing standard comb viscosity modifiers and a full DI package. Good results were obtained even with reduced dispersant, and excellent results were also confirmed for test oil 2.

[0089] Example 2

[0090] Table 3 shows four fully formulated engine oils with a blend viscosity grade of SAE 0W-12. The amounts of the components are given as % by weight based on the total weight of the composition.

[0091] The following components were used in Example 2:

[0092] GTL 4 is a Fischer-Tropsch-derived base oil with a kinematic viscosity (ASTM D445) of approximately 4 cSt at 100°C, which can be conveniently prepared by the method described in WO02070631.

[0093] GTL 3 is a Fischer-Tropsch-derived base oil with a kinematic viscosity (ASTM D445) of approximately 9.8 cSt at 40°C, which can be conveniently prepared by the method described in WO02070631.

[0094] The full DI package 2 - additive package contains anti-wear additives, detergents, non-succinimid dispersants and antioxidants, plus a polyisobutylene succinimid dispersant, which is present in an amount of 5.74% by weight of the dispersant based on the entire engine oil composition.

[0095] Modified DI Package 3 - The same additive package as Full DI Package 2, except that it does not contain polyisobutylene dispersant.

[0096] Modified DI Pack 4 - the same additive pack as Full DI Pack 2, except that it contains a polyisobutylene succinimide dispersant, which is present in an amount of 2.87% by weight of the dispersant based on the entire engine oil composition.

[0097] Viscoplex 3-201 viscosity modifier is available from Evonik.

[0098] Dispersant comb polymer - a dispersant comb polymer composed of the following: 13.7 wt% macromonomer (an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol); 51.5 wt% n-butyl methacrylate; 17.3 wt% LMA; 11.2 wt% styrene; 0.2 wt% methyl methacrylate; and 6.1 wt% N,N-dimethylaminoethyl methacrylate.

[0099] As shown in Table 3, test oil 3 (comparative) was formulated using a dispersant comb polymer and an unmodified DI package. Test oil 4 was formulated using a dispersant comb polymer and a modified DI package, which contained 50% less ashless dispersant compared to the unmodified DI package. Test oil 5 contained the same dispersant comb polymer but had a modified DI package containing 0% by weight of ashless dispersant compared to the unmodified DI package. A reference 0W-12 oil was formulated using an unmodified DI package and VP 3-201 as a viscosity modifier.

[0100] Table 3. Composition of base oil and test oil

[0101]

[0102] The rheological properties of each oil in Table 3 were measured, and the results are listed in Table 4.

[0103] Table 4

[0104] Benchmark 2 Test oil 3 Test oil 4 Test oil 5 Kinematic viscosity (ASTM D-445) 40℃ <![CDATA[mm 2 / s]]> 26.44 26.47 23.22 20.78 Kinematic viscosity (ASTM D-445) 100℃ <![CDATA[mm 2 / s]]> 5.84 5.85 5.78 5.72 Viscosity Index -- -- 174 175 210 244 HTHS (ASTM D-4683) 150℃ mPas 2.01 2.05 2.07 2.06 HTHS (ASTM D-6616) 80℃ mPas 6.30 6.40 5.80 5.50

[0105] Example 3

[0106] According to the new JASO GLV-1 specification, JASO M 365:2019 (Automotive Gasoline Engine Oils – Motor Drive Fuel Economy Test Procedure), motor drive fuel economy tests are conducted to measure motor drive friction torque and estimate the percentage improvement in fuel economy for various test oils. This test estimates the fuel economy improvement under Japanese WLTC and European WLTC test cycles based on motor drive friction torque measured at 50°C and 80°C. In this test, the oil's contribution to fuel economy improvement is calculated based on the reduction in motor drive friction torque of the tested oil relative to a standard reference oil. This torque change is confirmed before and after each test using the reference oil. The engine and test conditions used in the motor drive torque test are shown in Table 5.

[0107] Table 5

[0108]

[0109]

[0110] Motor drive friction torque tests were conducted on four 0W-12 candidates (baseline, test oil 3, test oil 4, and test oil 5). Figure 1 and Figure 2 The rate of reduction in motor-driven frictional torque for the four oils relative to the reference 0W-20 oil is shown at 50°C and 80°C. At both temperatures, the dispersant comb polymers containing test oils 3, 4, and 5 showed a greater torque reduction than the reference oils. These results indicate that the continuous reduction in ashless dispersant treatment in the additive package, permitted by the use of dispersant comb polymers, leads to an improvement in frictional torque reduction.

[0111] Fuel economy improvements are estimated based on the established correlation between the fuel economy of motor-driven vehicles and actual vehicle fuel economy tests. Table 6 shows the fuel economy improvements for two modes of reference oil candidates and test oil candidates – 1. LMH (low, medium, high speed) mode suitable for actual driving conditions in Japan or WLTC in Japan, and 2. LMHExH (low, medium, high speed, and ultra-high speed) mode simulating European driving conditions or WLTC in Europe.

[0112] Table 6

[0113]

[0114] These results demonstrate that the reduction in succinimide-type dispersants allowed by using the dispersant comb polymer of the present invention does indeed provide an improvement in fuel economy in real vehicles.

Claims

1. An engine oil composition comprising: i) Base oil in the range of 70% to 95% by weight, based on the total weight of the engine oil composition; ii) Dispersant comb polymer in the range of 0.01% to 15% by weight based on the total weight of the engine oil composition; iii) A package of modified dispersant inhibitor additives in the range of 4.99% to 15% by weight, based on the total weight of the engine oil composition. The dispersant comb polymer comprises the following: a. 13.7% by weight of a macromonomer, wherein the macromonomer is an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol; b. 51.5% by weight of n-butyl methacrylate; c. 17.3% by weight of LMA; d. 11.2% by weight of styrene; e. 0.2% by weight of methyl methacrylate; and f. 6.1% by weight of N,N-dimethylaminoethyl methacrylate; Based on the total weight of the modified dispersant inhibitor additive package, the modified dispersant inhibitor package contains 30% by weight or less of a succinimidyl dispersant, and The engine oil composition described herein has an SAE viscosity grade of 0W-X, where X is 30 or less.

2. The engine oil composition according to claim 1, wherein the base oil is a Fischer-Tropsch derived base oil.

3. The engine oil composition according to claim 1 or claim 2, wherein the succinimide dispersant is present in the modified dispersant inhibitor package in an amount at least 50% lower than that present when using the following viscosity modifiers, wherein the viscosity modifier is not a dispersant comb polymer consisting of: 13.7 wt% of a macromonomer, said macromonomer being an ester of methacrylic acid and hydroxylated hydrogenated polybutadiene with Mn of 4750 g / mol; 51.5 wt% of n-butyl methacrylate; 17.3 wt% of LMA; 11.2 wt% of styrene; 0.2 wt% of methyl methacrylate; and 6.1 wt% of N,N-dimethylaminoethyl methacrylate.

4. The engine oil composition according to claim 1 or claim 2, wherein the succinimide dispersant is present in an amount ranging from 0.01% by weight to 3.5% by weight of the engine oil composition.

5. The engine oil composition according to claim 1 or claim 2, wherein the succinimide dispersant is a polyolefin-substituted succinimide dispersant.

6. The use of the engine oil composition according to any one of claims 1 to 5 in an engine crankcase to reduce motor drive friction torque.

7. Use of the engine oil composition according to any one of claims 1 to 5 in an engine crankcase to improve fuel economy and viscosity characteristics.

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