A lubricating oil additive and composition for a flexible fuel engine

Abstract

The present invention discloses a lubricating oil additive for a flexible fuel engine, which comprises the following raw materials: overbased calcium alkyl salicylate, overbased sulfurized calcium alkylphenate, 4-pyridine ethylpropylene polymer, alkyl diphenylamine, 2,6-di-tert-butyl a-dimethylamino-p-cresol, and nano boron nitride BNNS. The present invention also discloses a lubricating oil composition for a flexible fuel engine, which comprises the above-mentioned lubricating oil additive for a flexible fuel engine, and further comprises an emulsifier and a base oil. The present invention can solve the key problem that a large amount of water is generated during the work combustion process of a flexible fuel engine, resulting in hydrolysis of dispersants, friction reducers and anti-wear agents in engine oil, damage to the molecular structure and loss of lubricating function. At the same time, it also solves the technical problem of difficult low-temperature cold start of a flexible fuel engine caused by water.

Description

Technical Field

[0001] The invention relates to the technical field of lubricating oils, in particular to a lubricating oil additive and a composition for a flexible fuel engine. Background Art

[0002] Flexible fuel refers to hydrogen fuel, ammonia fuel, and methanol fuel. The flexible fuel engine platform can switch between different fuels, including hydrogen fuel, ammonia fuel, and methanol fuel. Yuchai is the first flexible fuel engine platform in China to achieve commercial operation. Through independent controller development and universal cylinder head design, it can flexibly match various fuels by only adjusting the fuel system and software.

[0003] Compared with traditional fuels such as diesel and gasoline, the most significant feature of the combustion products of flexible fuel engines is that they produce a large amount of water in addition to acidic substances. The combustion characteristics and combustion products of flexible fuel engines also have different effects on the lubricating oil used in the engine. The following introduces the combustion characteristics of each fuel.

[0004] Methanol has many disadvantages as a fuel: 1. Unconventional emissions. Methanol engines do not burn completely under cold start conditions, and have high levels of unconventional emissions, such as formaldehyde, formic acid, unburned methanol, and trace amounts of hydrogen peroxide. These substances can poison DOC and other catalysts and make them ineffective. Corrosiveness. Substances such as formaldehyde and formic acid can cause serious corrosion to the materials of internal combustion engine parts. Unburned methanol can cause corrosion to the engine's plastic composite materials. 2. Methanol is a polar organic solvent, and some components in the engine's fuel supply system are made of plastic composite materials. Methanol can cause these materials to swell, resulting in an increase in volume and material hardness, and a brittle or softened texture. 3. The latent heat of vaporization of methanol is 3 to 4 times that of gasoline and diesel, and the heat absorbed is about 8.079 times that of gasoline. The lower boiling point and higher latent heat of vaporization reduce the intake temperature, making the fuel It is difficult to vaporize, and the concentration of the mixture cannot reach the flammable limit, resulting in difficulty in cold starting; 4. When methanol is mixed with conventional fuel, the attraction of the fuel molecules will decrease, resulting in increased volatility of methanol and air blockage, which will lead to poor fuel supply and affect the normal operation of the engine; 5. Since methanol itself supplies oxygen, under the same conditions, the water content in the engine crankcase will be higher than that of gasoline and diesel engines, and methanol is more likely to stratify after absorbing water, resulting in emulsification of the lubricating oil and causing the decomposition of the anti-wear agent in the engine lubricating oil, significantly reducing the anti-wear effect of the engine lubricating oil.

[0005] The combustion products of ammonia are water and acidic substances. The water in the combustion chamber mainly exists in the form of gas, but it will also condense into liquid water and settle to contact the lubricating oil when the temperature is too low, which may bring many impacts. High water content causes the phenomenon of oil emulsification. Additives such as ZDDP and detergents hydrolyze to remove calcium and produce precipitation. The water generated by the combustion of hydrogen fuel mixes into the oil pan. When the content exceeds the target requirement, it will cause its emulsification and cause the decomposition of anti-wear agents such as ZDDP in the engine oil, damage the engine oil film, wash the oil film on the friction surface, resulting in the dilution or thinning of the oil film on the friction surface, causing abnormal wear of parts and significantly reducing the anti-wear effect of the engine oil. A large amount of water generated by engine combustion leads to oil dilution and emulsification, and in the presence of oxygen, water and other corrosive impurities, it will cause the metal to undergo over-electrochemical corrosion or a rusting trend of discoloration. A large amount of acidic substances such as ammonia water are generated by ammonia combustion, resulting in a decrease in the base number of the oil. The combustion product of hydrogen is water, and its impact on lubricating oil is similar to that of methanol fuel and ammonia fuel.

[0006] Traditional engine lubricating oils include metal detergents, ashless dispersants, anti-oxidation and anti-corrosion agents, compound anti-oxidants, compound friction reducers, compound viscosity index improvers, pour point depressants, metal deactivators, base oils, etc. In the face of fuel engines in new fields, these single agents such as metal detergents, ashless dispersants, and ZDDP will decompose when encountering water, and their chemical structures are damaged, and the lubricating oil loses its properties such as cleaning and dispersing, anti-oxidation and anti-wear for protecting the engine. Because the combustion product water is less, traditional engine lubricating oils use demulsifiers to separate oil and water, but flexible fuel engines must choose the technical route of oil-water emulsification and cannot separate oil and water. Through experiments, it is found that oil-water separation will bring serious corrosion and wear, while uniform emulsified oil can well protect the metal surface of the engine.

[0007] For the flexible fuel engine platform that can switch different fuels, special lubricating oils are needed to solve the lubrication problem of this flexible fuel engine platform. In order to comprehensively meet the requirements of flexible fuels for lubricating oils, overcome the characteristics of high water content in the combustion products of flexible fuel engines, and solve the huge challenges brought by high water volume to engine oil, it is necessary to choose the technical route of non-separation of emulsified oil and water, solve the problem of a large amount of acidic substances brought by methanol and ammonia combustion, and at the same time solve problems such as engine oil emulsification, high-temperature detergency, low-speed pre-ignition, anti-wear and anti-corrosion performance, compatibility of the after-treatment system, and fuel economy. At present, there are no relevant research reports focusing on the development of dispersants and anti-oxidation and anti-wear agents that are not easily decomposed by water. Summary of the Invention

[0008] The object of the present invention is to provide a lubricating oil additive for a flexible fuel engine, which can solve the key problems that a large amount of water is generated during the work combustion process of the flexible fuel engine, resulting in hydrolysis of detergents, dispersants, friction reducing agents and anti-wear agents in the engine oil, the molecular structure is damaged, and the lubricating function is lost. At the same time, it also solves the technical problem that water causes difficult cold start of the flexible fuel engine at low temperature.

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

[0010] A lubricating oil additive for a flexible fuel engine, calculated by mass percentage based on the total mass of the engine oil of the flexible fuel engine, includes the following raw materials: overbased calcium alkyl salicylate 2.6% - 3.8%, overbased sulfurized calcium alkylphenate 1.0% - 1.8%, 4-pyridine ethylene-propylene polymer 15.0% - 16.8%, alkyl diphenylamine 3.0% - 4.5%, 2,6-di-tert-butyl α-dimethylamino-p-cresol 1.5% - 3.1%, nano boron nitride BNNS 3.0% - 8.0%.

[0011] Preferably, it further includes a metal corrosion inhibitor 0.005% - 0.01%.

[0012] Preferably, the metal corrosion inhibitor is benzotriazole.

[0013] The present invention also provides a lubricating oil composition for a flexible fuel engine, calculated by mass percentage based on the total mass of the engine oil of the flexible fuel engine, includes the following raw materials: overbased calcium alkyl salicylate 2.6% - 3.8%, overbased sulfurized calcium alkylphenate 1.0% - 1.8%, 4-pyridine ethylene-propylene polymer 15.0% - 16.8%, alkyl diphenylamine 3.0% - 4.5%, 2,6-di-tert-butyl α-dimethylamino-p-cresol 1.5% - 3.1%, nano boron nitride BNNS 3.0% - 8.0%, emulsifier 0.4% - 2.0%, and the balance is base oil.

[0014] Preferably, the emulsifier is V6-850, that is, the emulsifier product VISCOPLEX® 6-850 of Evonik Specialties (Shanghai) Co., Ltd.

[0015] Preferably, the base oil is CTL6 in Group III+ base oil.

[0016] Preferably, the preparation method of the lubricating oil composition for the flexible fuel engine is: mixing each raw material component evenly according to the mass percentage, and then it is obtained.

[0017] Preferably, the mixing temperature is 50 - 60 °C.

[0018] Preferably, the mixing process is stirred for at least 2 hours.

[0019] The present invention has the following beneficial effects:

[0020] (1) During the work combustion process of a flexible fuel engine, a large amount of water and acid are generated. The water can cause hydrolysis of various components in the engine oil. For example, calcium and magnesium detergents, dispersants, anti-wear agents containing amine, imine, and alcohol polar groups, especially the antioxidant and anti-corrosion agent ZDDP, are prone to hydrolysis. Hydrolysis causes the engine oil to lose its acid neutralization ability, the sediment dispersion performance to decline, it is difficult to form the key oil film of the engine, and the anti-wear ability to decrease. This can lead to engine rust, abnormal wear, cam wear, polishing, and seriously, problems such as bearing seizure and crankshaft damage. Therefore, the key point of the present invention is to use dispersants and friction-reducing and anti-wear agents that do not hydrolyze when encountering water, which can resist the negative impact brought by water and maintain the lubrication effect of the engine.

[0021] (2) The separation of engine oil and water can lead to serious mechanical wear, corrosion, and rust, and difficult cold start at low temperatures. In order to maintain a stable emulsion of oil and water and solve the problem of difficult cold start at low temperatures, traditional internal combustion engines add anti-emulsifiers and require complete separation of oil and water, while flexible fuel engine oils require the mixing of oil and water to form an emulsion. The present invention uses a pour point depressant and emulsifier, which has the functions of emulsification and reducing the low-temperature viscosity of the oil product, maintains a uniform emulsification effect of the engine oil, and performs excellently in cold start at low temperatures.

[0022] (3) Base oils are divided into Group I, Group II, Group III, and Group IV base oils. Through experiments, the present invention finds that the CTL6 Group III synthetic base oil from coal-to-olefins with high cost performance is easy to be compatible with water, has a better effect than other types of base oils, has excellent low-temperature performance, solves the problem of difficult cold start at low temperatures, and its price is much lower than that of Group IV base oils.

[0023] (4) Traditional dispersants include ashless dispersants such as mono-polyisobutylene succinimide dispersants, di-polyisobutylene succinimide dispersants, and borated polyisobutylene succinimide dispersants. These dispersants contain groups such as amine bonds, imine bonds, and alcohol polar groups, and are extremely prone to hydrolysis, losing the performance of the dispersant itself. To solve this problem, the present invention uses a 4-pyridine ethyl-propylene polymer dispersant with thickening and dispersing effects. The polymer dispersant with a 4-pyridine structure is not easy to hydrolyze and can bring a thickening effect to the engine oil.

[0024] (5) The antioxidant and anti-corrosion agents used in traditional lubricating oil compositions are zinc dialkyldithiophosphate and zinc diaryldithiophosphate. These additives are extremely prone to hydrolysis when in contact with water, losing their antioxidant and anti-corrosion functions for lubricating oil. To solve this problem, the anti-wear agent of the present invention uses a water-insoluble nano boron nitride BNNS anti-wear agent. The nano boron nitride BNNS anti-wear agent does not hydrolyze when encountering water, maintaining excellent anti-wear and friction-reducing properties of the lubricating oil. The lubricating oil contains a dispersant that enables the nano boron nitride BNNS composite material to be evenly and stably dispersed in the oil, and boron raw materials are easily obtainable in Guangxi. The antioxidants include shielded phenol type, aromatic amine type, phenol-amine type, and phenol ester type. The phenol ester type hydrolyzes when encountering water, while the shielded phenol type is effective only at low use temperatures. The combustion temperature of a flexible fuel engine is relatively higher than that of a traditional engine. Therefore, a combination of aromatic amine type and phenol-amine type is adopted. The amine type antioxidant is preferably alkyl diphenylamine, and the phenol-amine type uses 2,6-di-tert-butyl α-dimethylamino-p-cresol.

[0025] (6) Metal detergents include calcium salts and magnesium salts. Magnesium salts are very sensitive to water and are prone to hydrolysis and loss of performance. The present invention adopts a combination of calcium salts; and the basic components of metal detergents with different base numbers are different. The basic component of low-base-number calcium salts is mainly calcium hydroxide, while the basic components of high-base-number calcium salts are mainly calcium carbonate and a small amount of calcium hydroxide. Calcium hydroxide is more soluble in water than calcium carbonate; and there are more acidic substances generated by the combustion of ammonia fuel and methanol fuel; the present invention preferably adopts a combination of high-base-number calcium salicylate and calcium sulfonated alkylphenol.

[0026] (7) The common characteristics of flexible fuels, especially methanol fuel and ammonia fuel, are that in addition to a large amount of water generated by engine combustion, which causes oil dilution and emulsification, a large amount of acidic substances are also generated, and they are very corrosive to engine metals in the presence of oxygen, water, and other corrosive impurities; therefore, the present invention adds a metal corrosion inhibitor to well solve this problem.

[0027] (8) In order to meet the requirements of the after-treatment system, the ash content should not be greater than 1.0%, and the ash mainly comes from detergents and the antioxidant and anti-wear agent ZDDP. The present invention does not add ZDDP additive, which is different from the characteristic of traditional engine oil containing ZDDP. Therefore, it can increase the space for the dosage of calcium salt detergents, increase the base number of the engine oil, and strengthen the acid corrosion resistance of the engine oil. Specific Embodiments

[0028] Before further describing the specific embodiments of the present invention, it should be understood that the protection scope of the present invention is not limited to the following specific embodiments; it should also be understood that the terms used in the embodiments of the present invention are for describing specific embodiments and not for limiting the protection scope of the present invention.

[0029] Example 1

[0030] A lubricating composition for a flexible fuel engine, based on the total mass of the engine oil for the flexible fuel engine, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0031] Table 1

[0032]

[0033] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0034] Mix evenly according to the components and contents in Table 1, control the temperature at 50 °C, and stir for 2 hours until the composition is evenly mixed to obtain the lubricating product for the flexible fuel engine.

[0035] Example 2

[0036] A lubricating composition for a flexible fuel engine, based on the total mass of the engine oil for the flexible fuel engine, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0037] Table 2

[0038]

[0039] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0040] Mix evenly according to the components and contents in Table 2, control the temperature at 55 °C, and stir for 4 hours until the composition is evenly mixed to obtain the lubricating product for the flexible fuel engine.

[0041] Example 3

[0042] A lubricating composition for a flexible fuel engine, based on the total mass of the engine oil for the flexible fuel engine, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0043] Table 3

[0044]

[0045] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0046] Mix evenly according to the components and contents in Table 3, control the temperature at 60 °C, and stir for 3 hours until the composition is evenly mixed to obtain the lubricating product for the flexible fuel engine.

[0047] Comparative Example 1

[0048] A lubricating composition for a flexible fuel engine, based on the total mass of the engine oil for the engine, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0049] Table 4

[0050]

[0051] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0052] Mix the components and their contents in Table 4 evenly, control the temperature at 55 °C, and stir for 4 hours until the composition is evenly mixed to obtain the product.

[0053] Comparative Example 2

[0054] A lubricating composition for a flexible fuel engine, based on the total mass of the engine oil, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0055] Table 5

[0056]

[0057] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0058] Mix the components and their contents in Table 5 evenly, control the temperature at 55 °C, and stir for 4 hours until the composition is evenly mixed to obtain the product.

[0059] Comparative Example 3

[0060] A lubricating composition for a flexible fuel engine, based on the total mass of the engine oil, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0061] Table 6

[0062]

[0063] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0064] Mix the components and their contents in Table 6 evenly, control the temperature at 55 °C, and stir for 4 hours until the composition is evenly mixed to obtain the product.

[0065] Comparative Example 4

[0066] A lubricating composition for a flexible fuel engine, based on the total mass of the flexible fuel engine oil, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0067] Table 7

[0068]

[0069] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0070] Mix evenly according to the components and contents in Table 7, control the temperature at 55°C, and stir for 4 hours until the composition is mixed evenly to obtain the product.

[0071] Comparative Example 5

[0072] A lubricating composition for a flexible fuel engine, based on the total mass of the flexible fuel engine oil, calculated by mass percentage, the composition and content of its raw materials are as follows:

[0073] Table 8

[0074]

[0075] The preparation method of the lubricating composition for the flexible fuel engine is as follows:

[0076] Mix evenly according to the components and contents in Table 8, control the temperature at 55°C, and stir for 4 hours until the composition is mixed evenly to obtain the product.

[0077] Emulsion test experiment

[0078] 1. Emulsion stability test method: Take 100 g of the lubricating oils of Examples 1-2 and Comparative Examples 1-3, 10 g of methanol, and 10 g of water and add them to a beaker, and stir at a speed of 10000 r / min ± 2000 r / min for 2 min ± 2 s. Observe the emulsification situation during storage at normal temperature for 24 hours, 168 hours, 336 hours and at high temperature (150°C) for 168 hours; the analysis results are shown in Table 9.

[0079] Table 9 Test results of the physical and chemical properties of each engine oil composition

[0080]

[0081] It can be seen from the test results in Table 9 that the oil emulsions of Examples 1-3 of the present invention are very stable. After using the emulsifier, the oil can be stored for a long time at normal temperature and high temperature, and the oil and water do not separate, achieving the purpose of non-separation of oil and water for the lubricating oil used in flexible fuel engines. Comparative Example 1 does not contain an emulsifier, and the oil and water are easily separated; although Comparative Example 2 contains an emulsifier, a detergent with a low base number is used, and this type of detergent is prone to hydrolysis, and white precipitation is generated at the bottom layer, indicating that the micelle structure of the calcium salt of the detergent has been damaged and calcium hydroxide precipitates. Although Comparative Example 3 contains an emulsifier, traditional ZDDP is used, and precipitation is generated by hydrolysis in the presence of water.

[0082] 2. Conduct elemental analysis on Examples 1-2 and Comparative Examples 1-3 before and after emulsification respectively, and the analysis results are shown in Table 10.

[0083] Table 10 Test results of elemental analysis of each oil before and after emulsification

[0084]

[0085] As can be seen from the test results in Table 10, the oil emulsions of Examples 1-2 of the present invention are very stable, and the elements before and after emulsification do not change, so that the performance of the emulsified engine oil can be kept stable.

[0086] There is no emulsifier in Comparative Example 1, and the oil and water are stratified. Calcium, boron, and nitrogen elements do not appear in the water layer, indicating that after emulsification in Comparative Example 1, the boron nitride and calcium salts inside do not undergo hydrolysis.

[0087] In Comparative Example 2, although an emulsifier is contained, the calcium element in the lower layer is higher than that in the upper layer in the elemental analysis. The reason is that a detergent with a low base number is used. This type of detergent is prone to hydrolysis, and white precipitates are formed at the bottom layer, indicating that the micelle structure of the detergent calcium salt has been damaged, calcium hydroxide precipitates, and hard scale is easily formed at high temperatures, resulting in engine wear; and it cannot neutralize the acidic substances generated by combustion, and acid corrosion wear will occur in the engine.

[0088] In Comparative Example 3, although an emulsifier is contained, the zinc and phosphorus elements in the lower layer are higher than those in the upper layer in the elemental analysis. The reason is that it contains a traditional ZDDP antioxidant and anti-corrosion agent. In the presence of water, the zinc- and phosphorus-containing ZDDP has been hydrolyzed, and an oil film has not been formed, which will inevitably lead to a decrease in the antioxidant and anti-corrosion performance of the engine oil, a decrease in the anti-wear performance of the engine oil, and a shorter oil change interval.

[0089] 3. Analyze the base number of Examples 1-2 and Comparative Examples 1-2 before and after emulsification respectively; the analysis results are shown in Table 11.

[0090] Table 11 Test results of the base number of each oil product before and after emulsification

[0091]

[0092] The total base number of the oil product comes from detergents, dispersants, and antioxidants; alkaline detergents and antioxidants can continuously neutralize the oxygen-containing acids generated by the oxidation of lubricating oil and fuel during use, prevent them from further oxidizing and condensing, and thus reduce the paint film; when the engine oil contains water, the detergent will hydrolyze to produce precipitates, the base number will decrease, and the performance of the engine oil will decline; test the base number of the engine oil before and after emulsification.

[0093] As can be seen from the test results in Table 11, the oil emulsions of Examples 1-2 of the present invention are very stable, and the base number before and after emulsification does not change, so that the performance of the emulsified engine oil can be kept stable.

[0094] In Comparative Example 1, the slight decomposition of the detergent due to water emulsification causes a slight decrease in the base number, but the decrease amplitude is much lower than that in Comparative Example 2. Due to the influence of water in the oil product of Comparative Example 2, the structures of the detergent and antioxidant are damaged, and the base number decreases greatly, which will lead to a decrease in the acid-neutralizing performance of the oil product and the engine is prone to failure.

[0095] 4. Test the high-temperature deposit performance before and after the emulsification of the engine oil. The coking test is used for the test. The test conditions of the coking plate are as follows: the reaction temperature of the plate is 330 °C, the oil temperature is 150 °C, and the duration is 6 hours. The more the coke weight, the worse the anti-deposit performance of the oil product. The coking plate test results of the oil products before and after emulsification in Examples 1 to 3 and Comparative Example 2 are shown in Table 12.

[0096] Table 12 Coking plate test results of oil products before and after emulsification

[0097]

[0098] From the test results in Table 12, it can be seen that the test results of the oil emulsions in Examples 1 to 3 of the present invention for resisting the formation of high-temperature deposits are consistent with those before emulsification, indicating that even under the condition of high water content, the oil products of the present invention can still maintain excellent antioxidant and anti-deposit performance control. From the heat pipe test data of Comparative Example 2 before and after emulsification, it can be seen that the coke weight increases and the data becomes worse after emulsification, indicating that the detergent in the oil product of Comparative Example 2 undergoes hydrolysis and the performance decreases.

[0099] 5. Test the antioxidant deposit performance before and after the emulsification of the engine oil. The heat pipe test is used for the test. The test conditions of the heat pipe are as follows: the reaction temperature is 280 °C, the oil flow rate is 0.6 ml / s, and the duration is 16 hours. The worst result is 0 and the best is 9. The heat pipe test results of the oil products before and after emulsification in Examples 1 to 3 and Comparative Examples 3 to 4 are shown in Table 13.

[0100] Table 13 Heat pipe test results of oil products before and after emulsification

[0101]

[0102] From the test results in Table 13, it can be seen that the test results of the oil emulsions in Examples 1 to 2 of the present invention for antioxidant and anti-deposit formation are consistent with those before emulsification, indicating that even under the condition of high water content, the oil products of the present invention can still maintain excellent antioxidant and anti-deposit performance control. From the heat pipe test data of Comparative Example 3 and Comparative Example 4 before and after emulsification, it can be seen that the heat pipe data becomes worse after emulsification, indicating that the ZDDP in the oil product of Comparative Example 3 and the dispersant in Comparative Example 4 undergo hydrolysis and the performance decreases.

[0103] 6. Test the wear scar diameter performance before the emulsification of the engine oil. The four-ball machine is used to test the wear scar diameter. For the four-ball machine test, the test conditions are as follows: three steel balls with a diameter of 12.7 mm are clamped in an oil box and covered with the test oil, and another steel ball with the same diameter is placed on top of the three balls and is subjected to a force of 147 N (15 kgf) or 392 N (40 kgf), forming a "three-point contact". When the test oil reaches a certain temperature (75 °C ± 20 °C), the top ball rotates at a certain speed for 60 min. The anti-wear performance of the test oil is evaluated by the average value of the wear scar diameters of the following three balls. The results are shown in Table 14.

[0104] Table 14 Test Results of Wear Scar Diameter before and after Emulsification of Oil Products

[0105]

[0106] It can be seen from the test results in Table 14 that the wear scar diameters of the oil products in Examples 1 - 3 of the present invention remain consistent before and after emulsification, indicating that under the condition of high water content, the anti-wear agent in the oil product of the present invention does not hydrolyze, and the anti-wear performance of the engine oil is still maintained, which can provide sufficient anti-wear protection for the engine. However, it can be seen from the wear scar diameters before and after emulsification in Comparative Example 3 that the anti-wear performance has decreased by 44.7% because ZDDP is easily decomposed by water, causing the engine oil to lose its anti-wear performance.

[0107] 7. Test the rust prevention performance of the engine oil before and after emulsification. Immerse steel plates with standardized size and roughness in the lubricating oil, add a certain amount of formic acid, and leave it static in an oven at 120°C for 5 days. Observe the rust spots on the steel plates. The results are shown in Table 15.

[0108] Table 15 Test Results of Steel Sheet Corrosion before and after Emulsification of Oil Products

[0109]

[0110] It can be seen from the test results in Table 15 that the emulsions of the oil products in Examples 1 - 3 of the present invention are stable, the oil and water do not separate, and they contain corrosion inhibitors, so the anti-corrosion performance of the engine oil is still maintained; although Comparative Example 1 contains corrosion inhibitors, due to the separation of oil and water, the steel sheet still rusts severely; although the oil and water do not separate in Comparative Example 5, it does not contain corrosion inhibitors and rust still occurs. Therefore, it is necessary to add corrosion inhibitors to enhance the anti-corrosion performance of the lubricating oil for flexible fuel engines.

Claims

1. A lubricating oil additive for a flexible fuel engine, characterized in that based on the total mass of the lubricating oil for the flexible fuel engine, calculated by mass percentage, it comprises the following raw materials: 2.6% - 3.8% of overbased calcium alkyl salicylate, 1.0% - 1.8% of overbased sulfurized calcium alkylphenate, 15.0% - 16.8% of 4-pyridine ethylpropylene polymer, 3.0% - 4.5% of alkyl diphenylamine, 1.5% - 3.1% of 2,6-di-tert-butyl α-dimethylamino-p-cresol, 3.0% - 8.0% of nano boron nitride BNNS, 0.005% - 0.01% of metal corrosion inhibitor, 0.4% - 2.0% of emulsifier. The metal corrosion inhibitor is benzotriazole; the emulsifier is the emulsifier product VISCOPLEX® 6-850 of Evonik Specialties (Shanghai) Co., Ltd. This additive is used for the lubricating oil with CTL6 as the base oil.

2. A lubricating oil composition for a flexible fuel engine, characterized in that: it contains the lubricating oil additive for a flexible fuel engine described in claim 1.

3. The preparation method of the lubricating oil composition for a flexible fuel engine according to claim 2 is: mixing each raw material component evenly by mass percentage, then it is obtained.

4. The lubricating oil composition for a flexible fuel engine according to claim 2, characterized in that: the mixing temperature is 50 - 60 °C.

5. The lubricating oil composition for a flexible fuel engine according to claim 2, characterized in that: the mixing process is stirred for at least 2 hours.

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