Alcohol-resistant low-viscosity lubricating oil composition and use thereof

Abstract

An alcohol-resistant low-viscosity lubricating oil composition and the use thereof. The components of the lubricating oil composition include: 0.6-1.0% of a metal detergent, 6.0-10.0% of an ashless dispersant, 0.5-2.0% of an antioxidant anti-wear agent, 1.0-2.0% of a metal deactivator, 0.2-1.0% of an extreme-pressure anti-wear agent, 3.0-5.0% of a viscosity index improver, 0.1-0.2% of a pour point depressant, 0.001-0.010% of an anti-foaming agent, and 30.0-50.0% of a CTL base oil, the balance being an API group III base oil. The lubricating oil composition has good wear-resistant durability and low-temperature cold start performance.

Description

An alcohol-resistant low-viscosity lubricating oil composition and its application Technical Field

[0001] The invention belongs to the technical field of lubricating oils, and in particular relates to a lubricating oil composition whose performance meets the lubrication requirements of an M100 methanol passenger car engine. Background Art

[0002] The current viscosity grade of the M100 methanol engine oil for passenger cars is 5W-30. As methanol engine oil becomes more widely used, its use in cold winter regions (-36°C) has led to issues such as poor cold start performance (failure to start within 5 seconds) and excessive start-up wear (the oil's poor fluidity prevents it from reaching the engine components and providing lubrication). Furthermore, to meet the demand for longer oil change intervals, higher anti-wear properties are required for the oil.

[0003] Summary of the Invention

[0004] In order to solve the above problems, the object of the present invention is to provide an alcohol-resistant low-viscosity lubricating oil composition and its application, wherein the lubricating oil composition has excellent anti-wear durability and low-temperature cold starting performance.

[0005] To achieve the above objectives, the present invention systematically studies various types of additives and different types of base oils in lubricating oil compositions, and comprehensively and systematically studies the interactions and relationships among the various components. Addressing the issue of oil anti-wear durability is one of the key objectives. By effectively combining base oils, extreme pressure anti-wear agents, antioxidant anti-wear agents, metal deactivators, and the like, the present invention successfully addresses the issues of decreased anti-wear performance of lubricating oils in the presence of methanol, formic acid, and water, and poor cold startability of methanol engines at low temperatures.

[0006] The present invention provides an alcohol-resistant low-viscosity lubricating oil composition, which comprises, based on the total mass of the lubricating oil composition being 100%, 0.6-1.0% of a metal detergent (component A), 6.0-10.0% of an ashless dispersant (component B), 0.5-2.0% of an antioxidant and anti-wear agent (component C), 1.0-2.0% of a metal deactivator (component D), 0.2-1.0% of an extreme pressure and anti-wear agent (component E), 3.0-5.0% of a viscosity index improver (component F, also known as a viscosity index improver), 0.1-0.2% of a pour point depressant (component G), 0.001-0.010% of an anti-foaming agent (component H), 30.0-50.0% CTL base oil (component I), and the balance API III base oil (component J); wherein the antioxidant and anti-wear agent includes alkaline zinc dithiophosphate, amine ashless antioxidant, and phenolic ashless antioxidant; the metal deactivator includes a thiadiazole metal deactivator and a methylbenzotriazole metal deactivator; the extreme pressure anti-wear agent includes a sulfide extreme pressure anti-wear agent; in the antioxidant and anti-wear agent, the sulfur-to-phosphorus ratio of the alkaline zinc dithiophosphate is 1.8-1.9, and the zinc-to-phosphorus ratio is 1.1-1.2; in the extreme pressure anti-wear agent, the sulfur content of the sulfide extreme pressure anti-wear agent is 14.0-15.0%.

[0007] According to a specific embodiment of the present invention, preferably, the basic zinc dithiophosphate is basic bis(octyl)alkyl zinc dithiophosphate.

[0008] The present invention has conducted extensive research on different types of antioxidants and antiwear agents. The antioxidant and antiwear agent is a mixture of an amine ashless antioxidant, a phenolic ashless antioxidant, and an alkaline zinc dithiophosphate. Zinc dithiophosphate has excellent antioxidant, antiwear, and corrosion resistance. It is generally believed that it exerts its antioxidant effect by capturing free radicals and decomposing hydroperoxides. Due to the characteristics of methanol fuel, the increase in water in the combustion product greatly affects the antioxidant and antiwear properties of neutral ZDDP. Laboratory studies have shown that alkaline zinc dithiophosphate, such as basic bis(octyl)-1-alkyl zinc dithiophosphate, exhibits good system stability and wear resistance in the presence of water, alcohol, and acid. It also has a good synergistic effect with amine ashless antioxidants and phenolic ashless antioxidants, making it particularly suitable for methanol fuel engine oil. Ashless antioxidants can provide hydrogen atoms for peroxide free radicals, disrupting or preventing chain growth while generating low-energy, stable free radicals. Ashless antioxidants also exhibit synergistic effects, with phenolic antioxidants exhibiting a significant synergistic effect when used together with aminic antioxidants, as phenols aid in the regeneration of aromatic amines. The dosage of the antioxidant and antiwear agent in the present invention is limited to 0.5-2.0%, with a preferred range of 0.5-1.8%.

[0009] During use, oil products are oxidized and deteriorated due to the presence of oxygen, heat, and light. If the lubricating oil contains metals such as copper and iron, these metals, especially metal ions, will accelerate the oxidation rate of the oil, generating acid, sludge, and precipitation, causing corrosion and wear of metal parts. In order to avoid the catalytic acceleration of the auto-oxidation of lubricating oil by metal ions, the present invention has carried out extensive screening and compounding of different types of metal deactivators. The metal deactivator is a mixture of a thiadiazole-type metal deactivator and a methylbenzotriazole-type metal deactivator. Benzotriazole is an inhibitor of non-ferrous metals copper and silver. It can form a chelate with copper and is an effective metal deactivator, but its oil solubility is poor. In order to improve its oil solubility, a derivative of benzotriazole has been developed. When used in combination with a phenolic antioxidant (2,6-di-tert-butyl-p-cresol), it has a prominent synergistic effect. Thiadiazole-type metal deactivators are copper corrosion inhibitors that trap active sulfur, thereby deactivating the metal. They contain disulfide bonds and form a sulfide film on the metal surface, inhibiting the metal's catalytic oxidation of the oil, significantly increasing oxidation life and improving hydrolytic stability. The present invention limits the amount of metal deactivator to approximately 1.0-2.0% by weight of the total lubricating oil composition.

[0010] To ensure excellent anti-wear properties in a composition, it is crucial to select and combine different types of anti-wear agents and their appropriate proportions. For example, sulfide olefin anti-wear agents have high sintering resistance and good heat resistance, but poor anti-wear properties. Chlorinated paraffins have good anti-wear and extreme pressure properties and are highly active, but are unstable, prone to corrosion, and toxic. The better the performance of phosphate amine salt anti-wear agents, the worse their thermal stability. Nanoparticles also suffer from poor solubility and stability. The extreme pressure anti-wear agent in the present invention is a thioether-type extreme pressure anti-wear agent (such as dibenzyl disulfide), with a sulfur content of 14.0-15.0%. Thioether-type organic carboxylates can also be used as the thioether-type extreme pressure anti-wear agent in this application. Due to the presence of highly active polar groups ("ester groups") in ester oil molecules, these esters have excellent adsorption properties on electron-rich metal surfaces, facilitating the spread and maintenance of lubricating oil films. They offer outstanding anti-wear properties, excellent heat resistance, good thermal stability, and low corrosiveness, effectively addressing the failure of traditional anti-wear agents caused by methanol, formic acid, and water. The present invention limits the dosage of the extreme pressure anti-wear agent to 0.2-1.0%, with a preferred range of 0.2-0.8%.

[0011] According to a specific embodiment of the present invention, preferably, based on the mass of the antioxidant and anti-wear agent being 100%, the antioxidant and anti-wear agent includes 40-60% alkaline zinc dithiophosphate, 20-30% amine ashless antioxidant, and 10-20% phenolic ashless antioxidant; among the metal deactivators, the mass ratio of thiadiazole-type metal deactivator to methylbenzotriazole-type metal deactivator is 1:2-2:1.

[0012] According to a specific embodiment of the present invention, preferably, the composition of the lubricating oil composition includes: 0.7-1.0% metal detergent, 6.0-8.0% ashless dispersant, 0.5-1.8% antioxidant and antiwear agent, 1.0-2.0% metal deactivator, 0.2-0.8% extreme pressure antiwear agent, 3.0-5.0% viscosity index agent, 0.1-0.2% pour point depressant, 0.001-0.010% antifoaming agent, 30.0-40.0% CTL base oil, and the balance is API Group III base oil (preferably 30-60%).

[0013] According to a specific embodiment of the present invention, preferably, the metal detergent includes calcium salt and magnesium salt.

[0014] According to a specific embodiment of the present invention, preferably, the calcium salt comprises calcium salicylate and / or calcium sulfonate, and the magnesium salt comprises magnesium salicylate and / or magnesium sulfonate. Sulfonates are used in engine oils to neutralize acidic oxides formed during engine use, and to inhibit oxidation and deterioration of lubricating oils or reduce the formation of high-temperature deposits on the piston ring area under high temperature conditions, thereby keeping the engine clean. At the same time, they can solubilize non-oil-soluble colloids or oxides generated by lubricating oil oxidation and incomplete combustion of fuel into the oil, thereby suppressing the tendency to form deposits such as varnish, carbon deposits, and sludge. Alkyl salicylates are formed by introducing carboxyl groups into alkylphenols and transferring the metal from the hydroxyl position to the carboxyl position. This transformation makes the molecular polarity extremely strong, greatly improving high-temperature detergency, and having good high-temperature detergency, certain low-temperature dispersion, anti-oxidation and anti-corrosion, extreme pressure and anti-wear properties, and good synergy with other agents. Combining different types of detergents can create a synergistic effect, ensuring the oil has a certain base number to neutralize acidic substances while also providing good detergency, rust resistance, and low sulfate ash content. In the present invention, the metal detergent comprises approximately 0.6-1.0% of the total weight of the composition, with a preferred range of 0.7-1.0%. Using too little can result in reduced oil detergency, a low base number, and a shortened lubricant life. Using too much can increase the ash content of the lubricant, increase the frequency of low-speed pre-ignition, and affect the effectiveness of other functional additives without providing any other beneficial effects.

[0015] According to a specific embodiment of the present invention, the ashless dispersant preferably comprises polyisobutylene succinimide, more preferably a high-nitrogen, high-base-number polymer polyisobutylene succinimide having a nitrogen content of 1.8-2.2% and a base number of 46-55 mgKOH / g. Ashless dispersants are surfactants primarily used to disperse contaminants generated in the engine to ensure the free flow of oil. The dispersibility of ashless dispersants can help keep the engine clean and, in some cases, help maintain piston cleanliness. Different types of dispersants have different dispersing effects on sludge and deposits. High-base-number polymer dispersants generally have a better dispersing effect on deposits generated at high temperatures, while dispersants with average molecular weights have a better dispersing effect on sludge generated at low temperatures. The ashless dispersant of the present invention is a high-nitrogen, high-base-number polymer polyisobutylene succinimide. In addition to having a better dispersing effect, it can also help reduce the performance degradation of ZDDP, synergize with the anti-wear effect of extreme pressure anti-wear agents, and increase the base number reserve of the engine oil. The ashless dispersant accounts for approximately 6.0-10.0% of the total weight of the composition, with a preferred range of 6.0-8.0%. Using too little can result in reduced oil dispersibility, increased deposits on engine parts, and thicker sludge in the oil pan. Using too much can waste the additive and affect the effectiveness of other functional additives in the lubricating oil, without providing any other beneficial effects.

[0016] According to a specific embodiment of the present invention, the viscosity modifier preferably comprises an ethylene propylene copolymer, such as RHY615, 9230F, etc. The performance of a lubricating oil is closely related to the type and shear stability of the viscosity modifier. The viscosity modifier of the present invention preferably uses an ethylene propylene copolymer with a shear index of 20. The viscosity modifier of the present invention comprises approximately 3.0-5.0% of the total weight of the composition. Using too little of the viscosity modifier can result in low viscosity, reduced oil film thickness and stability, and reduced anti-wear performance in actual use. Using too much of the viscosity modifier can waste the additive, increase the oil viscosity, and reduce low-temperature performance and detergency, without any other beneficial effects.

[0017] According to a specific embodiment of the present invention, the pour point depressant preferably comprises polymethacrylate. The addition of a pour point depressant lowers the pour point of the lubricating oil, improving the performance of the lubricating oil in low-temperature environments. The present invention does not impose any particular limitation on the amount of pour point depressant added; however, it is typically 0.1-0.2% by weight of the total lubricating oil composition. If this amount is less than 0.1%, the amount is too small, resulting in the lubricating oil's pour point not meeting standard requirements and affecting its fluidity in low-temperature environments.

[0018] According to a specific embodiment of the present invention, the antifoaming agent preferably includes dimethyl silicone oil. Antifoaming agents can reduce the generation of foam during mechanical agitation of the lubricating oil during actual use, thereby preventing the problem of oil film rupture and wear of engine components caused by the generation of large amounts of foam during use. The amount of antifoaming agent added in the present invention is not particularly limited, but is generally 0.001-0.010% by weight of the total lubricating oil composition. If this value is less than 0.001%, the amount is too low, resulting in reduced antifoaming properties. If this value is greater than 0.010%, the amount is excessive, resulting in waste of the additive and no other beneficial effects.

[0019] According to a specific embodiment of the present invention, preferably, the CTL base oil has a kinematic viscosity of 3.8-4.2 mm at 100°C. 2 / s coal-based synthetic oil, more preferably 4mm 2 / s.

[0020] According to a specific embodiment of the present invention, preferably, the API III base oil has a kinematic viscosity of 3.8-4.3 mm at 100°C. 2 / s API III hydrocracked base oil, more preferably 4mm 2 / s.

[0021] According to a specific embodiment of the present invention, preferably, the lubricating oil composition has a sulfur content of 0.20-0.30 wt%, a phosphorus content of 0.06-0.07 wt%, a base number of 9.0-11.0 mgKOH / g, a sulfated ash content of 0.4-0.6 wt%, and a four-ball wear spot diameter of the lubricating oil composition is less than 0.8 mm after a 120-hour endurance test of an M100 methanol engine in accordance with NB / SH / T 0189, and the methanol engine starts within 3.5 seconds at -36°C.

[0022] According to a specific embodiment of the present invention, preferably, the base oils mentioned above are two high viscosity index base oil compositions whose performance meets the requirements of API Group III base oil standards.

[0023] The present invention also provides use of the lubricating oil composition in an M100 methanol passenger car engine.

[0024] Based on the action mechanism of additives, the present invention conducts systematic and complex screening and optimized compounding of different types of additives and additives of the same type but different compositions through a variety of simulation test methods. The key technical difficulties are ultimately solved through laboratory simulation tests and M100 methanol engine durability tests. The synergistic effect between the additives is improved by introducing and adjusting the types and proportions of additives. Compared with existing commercially available products, the present invention has better anti-wear performance and low-temperature cold starting performance, meets the lubrication requirements of the M100 methanol engine, demonstrates more excellent anti-wear durability in the M100 methanol engine durability test, and has better low-temperature cold starting performance in severely cold areas, thus solving the low viscosity and long oil change period requirements of methanol engine oil. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 is a photo of the piston pressure surface;

[0026] Figure 2 is a photo of the non-pressure-bearing surface of the piston;

[0027] Figure 3 is a photo of the oil pan. DETAILED DESCRIPTION

[0028] In order to have a clearer understanding of the technical features, objectives and beneficial effects of the present invention, the technical solution of the present invention is now described in detail below, but it should not be understood as limiting the scope of implementation of the present invention.

[0029] To screen base oils and additive components, the present invention employed laboratory tests such as PDSC (induction period), wear spot diameter, and low-temperature dynamic viscosity to evaluate the oil's oxidation stability, wear resistance, and low-temperature fluidity. The simulated test conditions were: a PDSC oxidation induction period temperature of 210°C, a mold plate diameter of 392N, and a low-temperature dynamic viscosity test temperature of -35°C.

[0030] Example 1:

[0031] This embodiment provides a lubricating oil composition, the raw materials used in 100 kg of the composition and their masses are as follows:

[0032] 0.5 kg of calcium salicylate with a base value of 265-295;

[0033] 0.5 kg of magnesium sulfonate with a base number of 395-430;

[0034] 8.0 kg of high molecular weight polyisobutylene succinimide (base value 46 mgKOH / g, nitrogen content 1.8%);

[0035] Basic bis(octyl) alkyl zinc thiophosphate (thiophosphate ratio 1.80, zinc-phosphorus ratio 1.1) 0.9 kg;

[0036] 1.0 kg of a mixture of p-diisooctyldiphenylamine and ester-type hindered phenol (VANLUBE BHC) (mass ratio 1:1);

[0037] 1.8 kg of a mixture of N,N-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine and 2,5-dimercapto-1,3,4-thiadiazole (mass ratio 1:1);

[0038] 0.8 kg of dibenzyl disulfide antiwear agent (sulfur content: 14%);

[0039] 4.0 kg of ethylene-propylene copolymer viscosity modifier (RHY615);

[0040] Polymethacrylate 0.2 kg;

[0041] Dimethyl silicone oil antifoaming agent 0.005Kg;

[0042] CTL base oil (100℃ viscosity 3.8-4.2mm 2 / s)40.0Kg;

[0043] API III Hydrogenated Base Oil (100℃ Viscosity 3.8-4.3mm 2 / s)42.195Kg;

[0044] The lubricating oil composition of this embodiment has a sulfur content of 0.28% and a phosphorus content of 0.067%.

[0045] Example 2:

[0046] This embodiment provides a lubricating oil composition, the raw materials used in 100 kg of the composition and their masses are as follows:

[0047] 0.5 kg of calcium salicylate with a base value of 320-360;

[0048] 0.4 kg of magnesium alkyl salicylate with a base number of 400;

[0049] 10.0 kg of high molecular weight polyisobutylene succinimide (base value 48 mgKOH / g, nitrogen content 1.8%);

[0050] 1.0 kg of basic bis(octyl) alkyl zinc thiophosphate (sulfur-phosphorus ratio 1.9, zinc-phosphorus ratio 1.1);

[0051] 1.0 kg of a mixture of p-diisooctyldiphenylamine and ester-type hindered phenol (VANLUBE BHC) (mass ratio 1:1);

[0052] 2.0 kg of a mixture of N,N-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine and 2,5-dimercapto-1,3,4-thiadiazole (mass ratio 1:1);

[0053] 0.5 kg of dibenzyl disulfide antiwear agent (sulfur content: 14%);

[0054] 4.0 kg of ethylene-propylene copolymer viscosity modifier (9230F);

[0055] Polymethacrylate 0.2 kg;

[0056] Dimethyl silicone oil antifoaming agent 0.005Kg;

[0057] CTL base oil (100℃ viscosity 3.8-4.2mm 2 / s)40.0Kg;

[0058] API III Hydrogenated Base Oil (100℃ Viscosity 3.8-4.3mm 2 / s)40.395Kg;

[0059] The lubricating oil composition of this embodiment has a sulfur content of 0.27% and a phosphorus content of 0.070%.

[0060] Example 3:

[0061] This embodiment provides a lubricating oil composition, the raw materials used in 100 kg of the composition and their masses are as follows:

[0062] The magnesium alkyl salicylate with a base number of 400 in Example 2 was replaced with magnesium sulfonate with a base number of 395-430. The other components were of the same quality. The lubricating oil composition of this example had a sulfur content of 0.30% and a phosphorus content of 0.068%.

[0063] Example 4:

[0064] This embodiment provides a lubricating oil composition, the raw materials used in 100 kg of the composition and their masses are as follows:

[0065] 0.7 kg of calcium salicylate with a base value of 265-295;

[0066] 0.3 kg of magnesium sulfonate with a base number of 395-430;

[0067] 6.0 kg of high molecular weight polyisobutylene succinimide (base value 47 mgKOH / g, nitrogen content 2.1%);

[0068] 1.0 kg of basic bis(octyl) alkyl zinc thiophosphate (sulfur-phosphorus ratio 1.8, zinc-phosphorus ratio 1.1);

[0069] 0.8 kg of a mixture of p-diisooctyldiphenylamine and ester-type hindered phenol (VANLUBE BHC) (mass ratio 1:1);

[0070] 1.0 kg of a mixture of N,N-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine and 2,5-dimercapto-1,3,4-thiadiazole (mass ratio 1:1);

[0071] 0.6 kg of dibenzyl disulfide antiwear agent (sulfur content: 14%);

[0072] Ethylene-propylene copolymer viscosity modifier (RHY615) 5.0 kg;

[0073] Polymethacrylate 0.2 kg;

[0074] Dimethyl silicone oil antifoaming agent 0.006Kg;

[0075] CTL base oil (100℃ viscosity 3.8-4.2mm 2 / s)50.0Kg;

[0076] API III Hydrogenated Base Oil (100℃ Viscosity 3.8-4.3mm 2 / s)34.394Kg;

[0077] The sulfur content of the lubricating oil composition of this embodiment is 0.22%, and the phosphorus content is 0.066%.

[0078] Example 5:

[0079] This embodiment provides a lubricating oil composition, the raw materials used in 100 kg of the composition and their masses are as follows:

[0080] 0.3 kg of calcium salicylate with a base value of 320-360;

[0081] 0.6 kg of magnesium alkyl salicylate with a base number of 400;

[0082] 7.0 kg of high molecular weight polyisobutylene succinimide (base value 46 mgKOH / g, nitrogen content 1.8%);

[0083] 1.0 kg of basic bis(octyl) alkyl zinc thiophosphate (sulfur-phosphorus ratio 1.8, zinc-phosphorus ratio 1.1);

[0084] 1.0 kg of a mixture of p-diisooctyldiphenylamine and ester-type hindered phenol (VANLUBE BHC) (mass ratio 1:1);

[0085] 1.5 kg of a mixture of N,N-di(2-ethylhexyl)-methyl-1H-benzotriazole-1-methylamine and 2,5-dimercapto-1,3,4-thiadiazole (mass ratio 1:1);

[0086] 0.8 kg of dibenzyl disulfide antiwear agent (sulfur content: 14%);

[0087] 4.0 kg of ethylene-propylene copolymer viscosity modifier (9230F);

[0088] Polymethacrylate 0.1 kg;

[0089] Dimethyl silicone oil antifoaming agent 0.005Kg;

[0090] CTL base oil (100℃ viscosity 3.8-4.2mm 2 / s)45.0Kg;

[0091] API III Hydrogenated Base Oil (100℃ Viscosity 3.8-4.3mm 2 / s)38.695Kg;

[0092] The lubricating oil composition of this embodiment has a sulfur content of 0.26% and a phosphorus content of 0.071%.

[0093] Comparative Example 1:

[0094] This comparative example provides a lubricating oil composition, the raw materials used in 100 kg of the lubricating oil composition and their masses are as follows:

[0095] The basic bis-octyl primary alkyl zinc thiophosphate in Example 1 was replaced with secondary alkyl zinc thiophosphate with a sulfur to phosphorus ratio of 2.1, and the other components were of the same mass. The lubricating oil composition of this comparative example had a sulfur content of 0.35% and a phosphorus content of 0.080%.

[0096] Comparative Example 2:

[0097] This comparative example provides a lubricating oil composition, the raw materials used in 100 kg of the lubricating oil composition and their masses are as follows:

[0098] The basic bis-octyl primary alkyl zinc thiophosphate in Example 1 was replaced with a secondary alkyl zinc thiophosphate with a sulfur-to-phosphorus ratio of 2.1, and the high-molecular-weight polyisobutylene succinimide was replaced with a boronated succinimide dispersant with a base number of 16. The other components were of the same mass. The lubricating oil composition of this comparative example had a sulfur content of 0.33% and a phosphorus content of 0.081%.

[0099] Comparative Example 3:

[0100] This comparative example provides a lubricating oil composition, the raw materials used in 100 kg of the lubricating oil composition and their masses are as follows:

[0101] The CTL base oil in Example 1 was replaced with API III hydrogenated base oil (viscosity 5.8-6.2 mm at 100 °C). 2 The lubricating oil composition of this comparative example has a sulfur content of 0.28% and a phosphorus content of 0.070%.

[0102] To verify the effect of the present invention, the engine lubricating oil prepared in the embodiment of the present invention was used to conduct laboratory simulation performance evaluation and engine bench test. The test results are shown in Table 1:

[0103] 1. Laboratory performance evaluation of lubricating oil compositions

[0104] Table 1 Lubricating oil composition performance evaluation results

[0105] As shown in Table 1, the lubricating oil of the present invention exhibits excellent oxidation resistance and wear resistance in PDSC oxidation induction period and wear spot diameter simulation tests. After a 120-hour M100 methanol engine endurance test, the wear spot diameter of the oil was less than 0.8 mm, surpassing the wear spot diameter of a commercially available methanol engine oil after a 100-hour endurance test. Excellent low-temperature fluidity was demonstrated in a -35°C low-temperature dynamic viscosity test. Example 1 completed a 5-second cold start test on a methanol vehicle at an outdoor temperature of -36°C, achieving a start-up performance of less than 3.5 seconds. Comparative Examples 1 and 2, while having similar PDSC performance, exhibited significant declines in their wear resistance after the addition of water, methanol, and formic acid, omitting the high-nitrogen, high-base polymer polyisobutylene succinimide in Comparative Example 2. In the wear test, severe seizure was even observed in the absence of high-nitrogen, high-base polymer polyisobutylene succinimide. Comparative Example 3 does not use the CTL4 base oil, resulting in a significant decrease in the low-temperature fluidity of the engine oil, and cannot achieve the excellent low-temperature fluidity effect of the present invention.

[0106] 2. Disassembly and inspection of the lubricating oil composition of Example 1 after the engine bench test

[0107] As shown in Figures 1 to 3 after the engine was disassembled and inspected, the lubricating oil composition of the present invention exhibited excellent detergency, dispersibility and anti-wear properties in the methanol engine test.

Claims

1. An alcohol-resistant low-viscosity lubricating oil composition, which, based on the total mass of the lubricating oil composition being 100%, comprises: 0.6-1.0% metal detergent, 6.0-10.0% ashless dispersant, 0.5-2.0% antioxidant and antiwear agent, 1.0-2.0% metal deactivator, 0.2-1.0% extreme pressure antiwear agent, 3.0-5.0% viscosity index agent, 0.1-0.2% pour point depressant, 0.001-0.010% antifoaming agent, 30.0-50.0% CTL base oil, the balance is API III base oil; Wherein, the antioxidant and anti-wear agent includes alkaline zinc dithiophosphate, amine ashless antioxidant, and phenol ashless antioxidant; The metal deactivator includes a thiadiazole type metal deactivator and a tolyltriazole type metal deactivator; The extreme pressure anti-wear agent includes a thioether type extreme pressure anti-wear agent; In the antioxidant and anti-wear agent, the sulfur-phosphorus ratio of the alkaline zinc dithiophosphate is 1.8-1.9, zinc-phosphorus ratio is 1.1-1.2; In the extreme pressure anti-wear agent, the sulfur content of the thioether type extreme pressure anti-wear agent is 14.0-15.0%.

2. The lubricating oil composition according to claim 1, wherein The alkaline zinc dithiophosphate is basic bis-octyl alkyl zinc dithiophosphate.

3. The lubricating oil composition according to claim 1 or 2, wherein Taking the weight of the antioxidant and anti-wear agent as 100%, the antioxidant and anti-wear agent comprises 40-60% alkaline zinc dithiophosphate, 20-30% amine ashless antioxidant, and 10-20% phenol ashless antioxidant; In the metal deactivator, the mass ratio of the thiadiazole type metal deactivator to the methylbenzotriazole type metal deactivator is 1:2-2:

1.

4. The lubricating oil composition according to claim 1, wherein The lubricating oil composition comprises: 0.7-1.0% metal detergent, 6.0-8.0% ashless dispersant, 0.5-1.8% antioxidant and antiwear agent, 1.0-2.0% metal deactivator, 0.2-0.8% extreme pressure and antiwear agent, 3.0-5.0% viscosity index agent, 0.1-0.2% pour point depressant, 0.001-0.010% antifoaming agent, 30.0-40.0% CTL base oil, the balance is API III base oil.

5. The lubricating oil composition according to claim 1, wherein The metal detergents include calcium salts and magnesium salts.

6. The lubricating oil composition according to claim 5, wherein The calcium salt includes calcium salicylate and / or calcium sulfonate, and the magnesium salt includes magnesium salicylate and / or magnesium sulfonate.

7. The lubricating oil composition according to claim 1, wherein The ashless dispersant includes polyisobutylene succinimide.

8. The lubricating oil composition according to claim 7, wherein The polyisobutylene succinimide has a nitrogen content of 1.8-2.2% and an alkali value of 46-55 mgKOH / g.

9. The lubricating oil composition according to claim 1, wherein The viscosity modifier includes ethylene propylene copolymer.

10. The lubricating oil composition according to claim 1, wherein The pour point depressant includes polymethacrylate.

11. The lubricating oil composition according to claim 1, wherein The anti-foaming agent includes dimethicone.

12. The lubricating oil composition according to claim 1, wherein The CTL base oil has a kinematic viscosity of 3.8-4.2 mm at 100°C. 2 / s of coal-based synthetic oil.

13. The lubricating oil composition according to claim 1, wherein The API III base oil has a kinematic viscosity of 3.8-4.3 mm at 100°C. 2 / s API III hydrocracking base oil.

14. The lubricating oil composition according to claim 1, wherein The lubricating oil composition has a sulfur content of 0.20-0.30 wt %, a phosphorus content of 0.06-0.07 wt %, a base number of 9.0-11.0 mgKOH / g, a sulfated ash content of 0.4-0.6 wt %, a four-ball wear spot diameter of less than 0.8 mm after a 120-hour endurance test of an M100 methanol engine in accordance with NB / SH / T 0189, and the methanol engine can be started within 3.5 seconds at -36°C.

15. Use of the lubricating oil composition according to any one of claims 1 to 14 in an M100 methanol passenger car engine.

Images