An engine lubricating oil composition and a method of making the same

Abstract

The application belongs to the technical field of lubricating oil, and particularly relates to an engine lubricating oil composition and a preparation method thereof. The engine lubricating oil composition comprises the following raw materials in parts by weight: base oil 78-95 parts, metal detergent 2-4 parts, antioxidant 1-2 parts, anti-oxidation, anti-corrosion and anti-wear agent 0.6-3 parts, corrosion inhibitor 0.1-0.5 parts, viscosity index improver 1-10 parts and soot dispersant 4-7 parts; the structure of the soot dispersant is shown as formula I. The engine lubricating oil composition has excellent low-temperature oil sludge dispersibility, soot dispersibility, oxidation resistance, high-temperature detergency and viscosity-temperature characteristics; and meanwhile, the stable dispersing effect is continuously maintained under the conditions of long period and high soot content.

Description

Technical Field

[0001] This invention belongs to the field of lubricating oil technology, specifically relating to an engine lubricating oil composition and its preparation method. Background Technology

[0002] To reduce particulate matter and CO2 emissions, engines currently employ technologies such as Exhaust Gas Recirculation (EGR) and Three-Way Catalytic Converters (TWC). However, this leads to increased engine heat load and more pronounced piston deposits. These deposits seep into the crankcase and come into contact with the lubricating oil, ultimately causing the oil viscosity to increase rapidly under high soot content, leading to engine wear. Therefore, higher requirements are placed on the dispersing performance of lubricating oils, especially for grades CK-4 and above, which have stringent requirements for soot dispersion. This necessitates rigorous validation through the Mack T-11 bench test. This test requires ashless dispersants to maintain stable dispersion over long periods under high soot content conditions, ensuring that the oil viscosity increase remains within acceptable limits throughout the test. If the dispersant performance is poor, soot will rapidly agglomerate, causing a sharp increase in lubricating oil viscosity and failing the test.

[0003] Ashless dispersants, as core additives in lubricating oils, are widely used in various engine oils. Their main function is to disperse sludge, varnish, and soot particles and other deposits generated by lubricating oil products due to long-term high-load operation, preventing them from accumulating and depositing on metal surfaces and causing wear on friction pairs, thereby preventing the increase of lubricating oil viscosity and improving the oxidation stability and service life of the oil.

[0004] Currently, the ashless dispersants used in oil product development are mainly conventional polyisobutylene succinimide products such as T151, T152, T161, and T154B. When exposed to high temperature and high speed for a long time, their thermal stability will gradually deteriorate, eventually leading to oxidation and decay, resulting in failure and shortening their service life. They are unable to effectively disperse deposits in oil products, especially soot particles.

[0005] The usual approach to solving the above problems is to add dispersible viscosity index improvers to the oil formulation to enhance the oil's viscosity retention capacity (such as US patents US5139688A, US6107257A, US15411123, and US10464614). These dispersible viscosity index improvers typically use multi-olefin copolymers as raw materials, undergoing chain-severing sol formation via a peroxide catalyst, followed by grafting with maleic anhydride under the action of an initiator to generate a multi-olefin copolymer olefin anhydride, which further reacts with an amine to obtain the final product. Preparation methods are illustrated in US patents US08987596, US17293721, and US13382555, as well as Chinese patents CN114717041B and CN101376860B. However, this type of dispersible viscosity index improver involves complex processes, multiple steps, and the use of large amounts of peroxide catalysts, posing safety risks. Furthermore, numerous influencing factors arise during preparation, making cross-linking side reactions likely, molecular weight control difficult, and production costs high.

[0006] Therefore, the development and compounding technology of multifunctional high-efficiency dispersants is a new technical route to solve the above problems. Chinese invention patent application CN119529210A discloses an ashless dispersant, its preparation method, and its application. This ashless dispersant is a compound prepared by the Mannich reaction of a multifunctional polar crosslinking agent A containing multiple reaction sites, a mono-linked aliphatic amine type polyisobutylene succinimide B and / or a mono-linked polyether amine type polyisobutylene succinimide C, and a paraformaldehyde compound D. The ashless dispersant has an overall star-shaped structure, and the multi-site grafted polyisobutylene olefin chains give it stronger suspension ability in oil products. Furthermore, the ashless dispersant prepared by this invention has excellent dispersing performance, antioxidant properties, and high-temperature detergency, and exhibits excellent storage stability after being added to oil products.

[0007] However, whether its excellent performance can be maximized still requires full consideration of its other additive components in lubricating oil and its blending with base oil, which still needs further in-depth research. Summary of the Invention

[0008] To address the aforementioned problems, this invention provides an engine lubricating oil composition and its preparation method. The soot dispersant used in this invention is synergistically compounded with other additives and base oils to form an additive compound system that exhibits excellent low-temperature sludge dispersibility, soot dispersibility, antioxidant properties, and high-temperature detergency. Simultaneously, it maintains stable dispersion effects and viscosity-temperature characteristics under long-term, high-sot content conditions.

[0009] To achieve the above objectives, the technical solution of the present invention is as follows:

[0010] In a first aspect, the present invention provides an engine lubricating oil composition, comprising, by weight, the following raw materials: 78-95 parts base oil, 2-4 parts metal detergent, 1-2 parts antioxidant, 0.6-3 parts antioxidant, anti-corrosion and anti-wear agent, 0.1-0.5 parts corrosion inhibitor, 1-10 parts viscosity index improver, and 4-7 parts soot dispersant; wherein the soot dispersant has the following structure:

[0011]

[0012] Wherein, R is -CH2-, -O- or -SO2-; R1 is -CH2-, -CH2CH2-, -CH(CH3)- or -CH(OH)-; R2, R3, R4, and R5 are each independently selected from mono-linked aliphatic amine type polyisobutylene succinimide or mono-linked polyether amine type polyisobutylene succinimide.

[0013] In some embodiments of the present invention, the structure of the mono-linked fatty amine type polyisobutylene succinimide is shown below:

[0014]

[0015] Wherein, the value of n is in the range of 1≤n≤8, and n is an integer.

[0016] In some embodiments of the present invention, the structure of the mono-linked polyetheramine type polyisobutylene succinimide is as follows:

[0017]

[0018] Where x and z take values ​​in the range of 1 ≤ (x + z) ≤ 4, and both x and z are integers; y takes values ​​in the range of 1 ≤ y ≤ 9, and y is an integer.

[0019] Furthermore, the base oil is selected from one or more of Group I base oils, Group II base oils, Group III base oils, poly-alpha olefin synthetic oils, ester synthetic oils, and polyether synthetic oils.

[0020] Preferably, the number average molecular weight of the soot dispersant is 6000-100000 g / mol; and / or the alkalinity is 18-45 mg KOH / g; and / or the nitrogen content is 0.5-2.4%.

[0021] More preferably, the number average molecular weight of the soot dispersant is 10,000-100,000 g / mol; and / or the alkalinity is 18-30 mg KOH / g; and / or the nitrogen content is 0.5-1.0%.

[0022] The higher the molecular weight of the soot dispersant of the present invention, the better its high-temperature detergency and soot dispersibility. At the same time, the viscosity-temperature characteristics are also significantly improved with the increase of molecular weight. Preferably, the soot dispersant has a number average molecular weight of 10,000-100,000 g / mol.

[0023] Furthermore, the higher the nitrogen content of the soot dispersant, the higher its alkalinity and the stronger its polarity. However, excessively high nitrogen content can be corrosive. Therefore, to balance dispersing performance and corrosion resistance and achieve a better overall effect, the soot dispersant is preferably 18-45 mg KOH / g; and / or has a nitrogen content of 0.5-2.4%; more preferably, it has an alkalinity of 18-30 mg KOH / g; and / or has a nitrogen content of 0.5-1.0%.

[0024] Furthermore, the metal detergent is selected from one or more of alkyl salicylate calcium, alkyl salicylate magnesium, alkyl sulfonate calcium, alkyl sulfonate magnesium, and alkylphenol sulfide calcium.

[0025] Preferably, the metal detergent is alkyl salicylate calcium and sulfide alkylphenol calcium.

[0026] Furthermore, the antioxidant is selected from one or more of phenolic antioxidants, phenolic ester antioxidants, and amine antioxidants.

[0027] Preferably, the antioxidant is a phenolic antioxidant or an amine antioxidant.

[0028] More preferably, the antioxidant is 2,6-di-tert-butyl-p-cresol, octylbutyldiphenylamine, and / or N-phenyl-α-naphthylamine.

[0029] Furthermore, the antioxidant and anticorrosive agent is selected from one or more of zinc butyl octyl dithiophosphate, zinc dioctyl dithiophosphate, zinc basic dithiophosphate, and zinc isopropyl isooctyl dithiophosphate.

[0030] Preferably, the antioxidant and anticorrosive agent is zinc dioctyl dithiophosphate, zinc basic dithiophosphate, and / or zinc isopropyl isooctyl dithiophosphate.

[0031] Furthermore, the corrosion inhibitor is selected from one or more of acidic phosphate amine salts and benzotriazole and their derivatives.

[0032] Preferably, it is butyl isooctyl phosphate dodecylamine salt and / or benzotriazole.

[0033] Furthermore, the viscosity index improver is selected from polymethacrylate and / or olefin copolymers.

[0034] Secondly, the present invention provides a method for preparing the above-mentioned engine lubricating oil composition, specifically comprising the following steps:

[0035] (1) Take antioxidant, antioxidant, anti-corrosion and anti-wear agent and corrosion inhibitor in sequence, heat and stir to mix them thoroughly;

[0036] (2) Then add the metal cleaning agent, continue to heat and stir to mix it thoroughly, and obtain the additive compound;

[0037] (3) Continue heating and add base oil, soot dispersant, viscosity index improver and the above additive compound in sequence. Mix thoroughly under stirring conditions to obtain the final product.

[0038] Furthermore, in step (1), the heating temperature is 55-65℃ and the stirring time is 3-6h.

[0039] Furthermore, in step (2), the temperature is raised to 60-65℃ and the stirring time is 3-6h.

[0040] Furthermore, in step (3), the heating temperature is 65-75℃ and the stirring time is 3-6h.

[0041] Compared with the prior art, the present invention has the following beneficial effects:

[0042] This invention is the first to use a star-shaped soot dispersant in a lubricating oil composition. It has a high molecular weight and strong polarity. Through the steric hindrance effect of the polymer chain and the anchoring of the soot surface by polar groups, it effectively prevents agglomeration and has strong suspension ability in oil. At the same time, it has excellent high-temperature detergency, antioxidant properties, soot dispersing performance and viscosity-temperature characteristics.

[0043] This invention solves the problem of a sharp increase in lubricating oil viscosity caused by soot agglomeration by synergistically compounding the soot dispersant with other additives and base oils to form an additive compound system that does not require the addition of dispersible viscosity index improvers.

[0044] Furthermore, the soot dispersant of this invention solves the problem of conventional dispersants failing to disperse soot particles due to oxidative decay under long-term high-temperature and high-speed environments. The formulated CK-4 grade oil maintains stable dispersion under long-term, high-soil-content conditions, and has passed the rigorous Mack T-11 bench test. It overcomes the technical challenge of a dramatic increase in oil viscosity caused by the adoption of exhaust gas recirculation (EGR) technology in engines and the generation of large amounts of high-content soot under harsh operating conditions. Detailed Implementation

[0045] The embodiments of the present invention are described in detail below: The embodiments of the present invention are implemented under the premise of the technical solution of the present invention, and detailed implementation methods and processes are given. However, the protection scope of the present invention is not limited to the following embodiments. The process parameters in the following embodiments that do not specify specific conditions are generally in accordance with conventional conditions.

[0046] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0047] The present invention will be further described below with reference to specific embodiments. The scope of protection of the present invention is not limited by the following embodiments. Unless otherwise specified, the main materials involved in the embodiments are all conventional commercially available products.

[0048] Soot dispersants D1-D12 were prepared according to the preparation method of Examples 1-12 in Chinese Invention Patent Application CN202311116241.8. The physicochemical properties of the soot dispersants and the commercially available high molecular weight butadiene imine ashless dispersant T161 are shown in Table 1 below.

[0049] The alkalinity was determined using the standard SH / T0251 method, the nitrogen content using the standard GB / T17674 method, the number-average molecular weight using the standard Q / SY RH 4002 method, and the thickening ability using the standard SH / T 0566 method.

[0050] Table 1 Physicochemical properties of dispersants

[0051] Alkalinity (mg KOH / g) Nitrogen content (%) Number-average molecular weight (g / mol) <![CDATA[Thickening capacity (mm 2 / s)]]> D1 42.9 2.19 6188 4.2 D2 36.4 1.31 8025 5.1 D3 32.7 1.27 8751 5.5 D4 18.6 0.92 10754 5.7 D5 41.7 2.12 6132 4.9 D6 34.8 1.30 8168 5.3 D7 31.5 1.25 8732 5.6 D8 18.4 0.91 10732 5.9 D9 41.2 2.11 6178 5.0 D10 35.2 1.30 8180 5.5 D11 31.9 1.26 8786 5.9 D12 19.1 0.92 10787 6.3 T161 22.5 1.14 2636 2

[0052] Example 1

[0053] An additive compound package, the composition of which is shown in Table 2.

[0054] Table 2. Composition of Additive Compound (parts by weight)

[0055]

[0056] The preparation method is as follows:

[0057] Antioxidant, antioxidant, anti-corrosion and anti-wear agent and corrosion inhibitor were taken in sequence, heated to 65℃ and stirred for 3 hours to make them fully mixed; then metal detergent was added and stirred for another 3 hours to make them fully mixed, so as to obtain additive compound F1.

[0058] Example 2

[0059] An additive compound package, the composition of which is shown in Table 3.

[0060] Table 3. Composition of Additive Compound (parts by weight)

[0061]

[0062] The preparation method is as follows:

[0063] Antioxidant, antioxidant, anti-corrosion and anti-wear agent and corrosion inhibitor were taken in sequence, heated to 65℃ and stirred for 3 hours to make them fully mixed; then metal detergent was added and stirred for another 3 hours to make them fully mixed to obtain additive compound F2.

[0064] Example 3

[0065] An additive compound package, the composition of which is shown in Table 4.

[0066] Table 4. Composition of Additive Compound (parts by weight)

[0067]

[0068]

[0069] The preparation method is as follows:

[0070] Antioxidant, antioxidant, anti-corrosion and anti-wear agent and corrosion inhibitor were taken in sequence, heated to 65℃ and stirred for 3 hours to make them fully mixed; then metal detergent was added and stirred for another 3 hours to make them fully mixed, so as to obtain additive compound F3.

[0071] Examples 4-12, Comparative Examples 1-3

[0072] The engine lubricating oil composition was prepared according to the raw material composition and dosage in Table 5. The specific preparation method was as follows: the base oil, soot dispersant, viscosity index improver and additive compound were heated to 70°C and stirred for 5 hours to fully mix, and the product was obtained.

[0073] Table 5. Composition of Engine Oil Lubricating Oil Composition (Unit: wt%)

[0074]

[0075] The engine lubricating oil compositions prepared in Examples 4-12 and Comparative Examples 1-3 were evaluated for performance as follows.

[0076] (1) Evaluation of low-temperature sludge dispersibility

[0077] The evaluation of the low-temperature dispersibility of ashless dispersants was conducted according to Appendix A of SH / T 0623-1995 "Bisuccinimide Dispersants". The specific steps are as follows:

[0078] 11g of test sample and 9g of oil sludge were mixed into a 50mL beaker and stirred at 150℃ for 1.5 hours. While still hot, a drop of the test oil was placed on filter paper and placed in an oven at 80℃ for 2 hours. The ratio of the oil sludge diffusion zone to the oil zone was measured to obtain the spot test data. A higher spot dispersion value indicates better low-temperature oil sludge dispersibility.

[0079] (2) Simulation evaluation of soot dispersion

[0080] The soot dispersion was evaluated using a diesel engine soot dispersion assessor. The specific steps are as follows:

[0081] Weigh 40g of the test sample and place it into a steel pipe to serve as the soot absorption tube. Keep the pipe at a constant temperature of 100℃ in an oil bath. Soot produced after diesel combustion is drawn into the absorption tube. As time increases, the soot content in the tube gradually increases, the viscosity of the oil gradually increases, and the negative pressure in the tube slowly rises. When the negative pressure in the tube reaches -1200Pa, the absorption time is recorded. The longer the absorption time, the stronger the oil's soot-carrying capacity and the better its soot dispersion performance.

[0082] (3) Antioxidant evaluation

[0083] The antioxidant properties were evaluated according to the Rotating Bomb Oxygen Test (RPVOT) method (SH / T 0193-1992). The longer the RPVOT time, the better the high-temperature oxidation resistance of the dispersant.

[0084] (4) Evaluation of high-temperature cleanliness

[0085] Referring to the relevant standards in SH / T 0300-1992 "Crankcase Simulation Test Method", the coking plate test was conducted, and the specific steps are as follows:

[0086] The parameters of the coking plate tester were set as follows: plate temperature 310℃, oil temperature 100℃, and oil was continuously splashed for 2 hours before examining the formation of a varnish film. This method involves splashing additive-containing internal combustion engine oil onto a high-temperature metal surface to form a varnish film, thus simulating the amount of coking in the crankcase during piston operation. The high-temperature detergency of the oil is evaluated by measuring the weight of the coke on the metal plate. The lower the amount of coking, the better the high-temperature detergency.

[0087] The performance evaluation results are shown in Table 6.

[0088] Table 6 Performance Evaluation Results of Engine Lubricating Oil Compositions

[0089]

[0090]

[0091] As can be seen from the table above, compared with the conventional ashless dispersant T161, the soot dispersant of the present invention significantly improves the soot dispersion performance, antioxidant properties and high-temperature detergency when applied to the diesel engine oil system.

[0092] Comparative Example 4

[0093] An additive compound package, the composition of which is shown in Table 7.

[0094] Table 7. Composition of Additive Compounds (parts by weight)

[0095]

[0096] The preparation method is the same as in Example 1, and additive compound F4 is obtained.

[0097] Comparative Example 5

[0098] An additive compound package, the composition of which is shown in Table 8.

[0099] Table 8. Composition of Additive Compounds (parts by weight)

[0100]

[0101]

[0102] The preparation method is the same as in Example 1, and additive compound F5 is obtained.

[0103] Comparative Example 6

[0104] An additive compound package, the composition of which is shown in Table 9.

[0105] Table 9. Composition of Additive Compounds (parts by weight)

[0106]

[0107] The preparation method is the same as in Example 1, and additive compound F6 is obtained.

[0108] Comparative Examples 7-9

[0109] The engine lubricating oil composition was prepared according to the raw material composition and dosage in Table 10. The specific preparation method was as follows: the base oil, soot dispersant, viscosity index improver and additive compound were heated to 70°C and stirred for 5 hours to fully mix, and the product was obtained.

[0110] Table 10 Engine Oil Lubricating Composition (Unit: wt%)

[0111]

[0112] The performance evaluation results of the engine lubricating oil compositions prepared in Comparative Examples 7-9 are shown in Table 11.

[0113] Table 11 Performance Evaluation Results of Engine Lubricating Oil Compositions

[0114] Sludge Spot Dispersion Value / % Soot dispersion / hour RPVOT / min Coking amount / mg Example 4 64 5.8 40 256 Comparative Example 7 55 5.2 29 418 Comparative Example 8 58 5.5 32 421 Comparative Example 9 53 5.3 35 407

[0115] As can be seen from the table above: Compared with Example 4, Comparative Example 7 did not use an antioxidant in its additive composite, and the amount of dispersant D4 with antioxidant properties was increased accordingly, resulting in a decrease in its soot dispersion performance, antioxidant properties, and high-temperature detergency; Compared with Example 4, Comparative Example 6 lacked a metal detergent and a corrosion inhibitor, and the amount of dispersant D4 with high-temperature detergency properties was increased accordingly, resulting in a decrease in its soot dispersion performance, antioxidant properties, and high-temperature detergency; Compared with Example 4, although the amount of each component in the additive composite was increased in Comparative Example 9, the dispersant was replaced with a common ashless dispersant, resulting in a decrease in all aspects of its performance. It is evident that the various combinations in the additive composite of this invention work synergistically with the soot dispersant, resulting in superior overall performance.

[0116] (5) Viscosity-temperature characteristics

[0117] Viscosity-temperature characteristics mainly include thickening ability and high-temperature high-shear viscosity. The engine lubricating oil compositions prepared in the comparative examples above were subjected to high-temperature high-shear viscosity (HTHS) testing using the standard SH / T 0618 method at 150℃ for 106 seconds. -1 The measurements were taken under the specified conditions, and the results are shown in Table 12.

[0118] Table 12 Viscosity-temperature characteristics of engine lubricating oil compositions

[0119]

[0120]

[0121] As can be seen from the table above, the soot dispersant of the present invention, when combined with various additives, also has excellent viscosity-temperature characteristics, without the need for additional dispersible viscosity index improvers.

[0122] Comparative Example 10

[0123] Based on Comparative Example 3, an additional 5% of dispersible viscosity index improver H5777 was added.

[0124] (6) Evaluation of smoke dispersion performance by bench test

[0125] Mack T-11 bench tests were conducted on Example 12, Comparative Example 3, and Comparative Example 10, and the results are shown in Table 13.

[0126] Table 13 Test Results of Engine Lubricating Oil Compositions (Mack T-11)

[0127]

[0128] As can be seen from the table above, the CK-4 grade lubricating oil of this invention (Example 12) maintains a stable dispersion effect under long-term, high soot content conditions, and has passed the rigorous Mack T-11 bench test. In contrast, the lubricating oil formulated with the conventional ashless dispersant T161 performed poorly in the Mack T-11 bench test and failed. Only after adding a dispersing viscosity index improver to the T161-formulated lubricating oil did it barely pass the test. This further demonstrates that this invention possesses excellent low-temperature sludge dispersibility, soot dispersibility, oxidation resistance, high-temperature detergency, and viscosity-temperature characteristics.

[0129] Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, and is not intended to limit the scope of protection of the present invention. Simple modifications or equivalent substitutions made by those skilled in the art to the technical solution of the present invention do not depart from the essence and scope of the technical solution of the present invention.

Claims

1. An engine lubricating oil composition, characterized in that, By weight, it comprises the following raw materials: 78-95 parts base oil, 2-4 parts metal detergent, 1-2 parts antioxidant, 0.6-3 parts antioxidant, anti-corrosion and anti-wear agent, 0.1-0.5 parts corrosion inhibitor, 1-10 parts viscosity index improver, and 4-7 parts soot dispersant; the structure of the soot dispersant is as follows: Wherein, R is -CH2-, -O- or -SO2-; R1 is -CH2-, -CH2CH2-, -CH(CH3)- or -CH(OH)-; R2, R3, R4, and R5 are each independently selected from mono-linked aliphatic amine type polyisobutylene succinimide or mono-linked polyether amine type polyisobutylene succinimide.

2. The engine lubricating oil composition according to claim 1, characterized in that, The soot dispersant has a number average molecular weight of 6000-100000 g / mol; and / or an alkalinity of 18-45 mg KOH / g; and / or a nitrogen content of 0.5-2.4%.

3. The engine lubricating oil composition according to claim 2, characterized in that, The soot dispersant has a number average molecular weight of 10,000-100,000 g / mol; and / or an alkalinity of 18-30 mg KOH / g; and / or a nitrogen content of 0.5-1.0%.

4. The engine lubricating oil composition according to claim 1, characterized in that, The base oil is selected from one or more of Group I base oils, Group II base oils, Group III base oils, poly-alpha olefin synthetic oils, ester synthetic oils, and polyether synthetic oils.

5. The engine lubricating oil composition according to claim 1, characterized in that, The metal cleaning agent is selected from one or more of alkyl salicylate calcium, alkyl salicylate magnesium, alkyl sulfonate calcium, alkyl sulfonate magnesium, and alkylphenol sulfide calcium.

6. The engine lubricating oil composition according to claim 5, characterized in that, The metal cleaning agent is alkyl salicylate calcium and sulfide alkylphenol calcium.

7. The engine lubricating oil composition according to claim 1, characterized in that, The antioxidant is selected from one or more of phenolic antioxidants, phenolic ester antioxidants, and amine antioxidants.

8. The engine lubricating oil composition according to claim 7, characterized in that, The antioxidants are phenolic antioxidants and amine antioxidants.

9. The engine lubricating oil composition according to claim 8, characterized in that, The antioxidant is 2,6-di-tert-butyl-p-cresol, octylbutyldiphenylamine, and / or N-phenyl-α-naphthylamine.

10. The engine lubricating oil composition according to claim 1, characterized in that, The antioxidant and anticorrosive agent is selected from one or more of zinc butyl octyl dithiophosphate, zinc dioctyl dithiophosphate, zinc basic dithiophosphate, and zinc isopropyl isooctyl dithiophosphate.

11. The engine lubricating oil composition according to claim 10, characterized in that, The antioxidant and anticorrosive agent is zinc dioctyl dithiophosphate, zinc basic dithiophosphate, and / or zinc isopropyl isooctyl dithiophosphate.

12. The engine lubricating oil composition according to claim 1, characterized in that, The corrosion inhibitor is selected from one or more of acidic phosphate amine salts and benzotriazole and its derivatives.

13. The engine lubricating oil composition according to claim 12, characterized in that, Butyl isooctyl phosphate dodecylamine salt and / or benzotriazole.

14. The engine lubricating oil composition according to claim 1, characterized in that, The viscosity index improver is selected from polymethacrylate and / or olefin copolymers.

15. A method for preparing the engine lubricating oil composition according to any one of claims 1-14, characterized in that, Includes the following steps: (1) Take antioxidant, antioxidant, anti-corrosion and anti-wear agent and corrosion inhibitor in sequence, heat and stir to mix them thoroughly; (2) Then add the metal cleaning agent, continue to heat and stir to mix it thoroughly, and obtain the additive compound; (3) Continue heating and add base oil, soot dispersant, viscosity index improver and the above additive compound in sequence. Mix thoroughly under stirring conditions to obtain the final product.

16. The preparation method according to claim 15, characterized in that, In step (1), the heating temperature is 55-65℃, and the stirring time is 3-6 hours; In step (2), the temperature is raised to 60-65℃ and the stirring time is 3-6 hours; In step (3), the temperature is raised to 65-75℃ and the stirring time is 3-6h.

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