Engine cooling system exchange medium as well as preparation method and application thereof

Abstract

The invention discloses a machine changing medium for an engine cooling system and a preparation method and application of the machine changing medium for the engine cooling system, and the machine changing medium for the engine cooling system comprises the following components in percentage by weight: 85-95% of a cooling medium, 1-5% of a corrosion inhibitor, 0.4-1.0% of a pH regulator, 0.01-0.1% of a hard water stabilizer, 0.01-0.04% of a defoaming agent and 0.001-0.01% of a coloring agent. The engine cooling system machine changing medium has the advantages of being environmentally friendly, multi-metal, resistant to corrosion, resistant to high temperature and the like, is good in heat transfer, heat dissipation and cooling effect, can be well compatible with cooling liquid and is suitable for cooling systems of fuel engines and hybrid power engines.

Description

Technical Field

[0001] The present invention relates to the technical field of engine coolant, and more specifically, to an engine cooling system replacement medium and a preparation method and application thereof. Background Art

[0002] The engine cooling system replacement medium, that is, the cooling medium used during the test run before the car is put on the market, is currently mainly composed of a base fluid (deionized water, antifreeze) and a variety of additives. With the rapid development of the automobile industry, the engine adopts a more compact and larger specific power design, and the waste heat density generated by the engine has also increased significantly. This not only places higher and higher performance requirements on the engine itself, but also continuously improves the performance requirements on the engine cooling system. The coolant is not only required to have a lower freezing point and a higher boiling point, but also to have better metal corrosion resistance, cavitation resistance, anti-fouling, and a longer service life. CN104962245A discloses a high-temperature degradation-resistant long-life gas engine coolant, which is composed of a mixture of 2,3-dihydroxybenzoic acid and acetylsalicylic acid as a thermal stability improvement additive, sodium nitrate, sodium molybdate, adipic acid, benzoic acid, methyl silicone oil, dye, glycol coolant, water, and pH regulator. Among them, sodium nitrate is used as an inorganic corrosion inhibitor, which has certain toxicity and has negative effects on the environment and human health. In addition, there is a critical concentration problem for the protection of metals, which affects the anti-corrosion effect. Summary of the invention

[0003] An object of the present invention is to provide an engine cooling system replacement medium and a preparation method and application thereof. The engine cooling system replacement medium has the advantages of environmental protection, multi-metal corrosion protection, high temperature resistance, etc., has good heat transfer, heat dissipation and cooling effects, and is well compatible with coolant.

[0004] In order to achieve these purposes and other advantages according to the present invention, according to one aspect of the present invention, the present invention provides an engine cooling system replacement medium, which includes the following components by weight percentage: 85-95% cooling medium, 1-5% corrosion inhibitor, 0.4-1.0% pH adjuster, 0.01-0.1% hard water stabilizer, 0.01-0.04% defoamer, and 0.001-0.01% colorant; wherein the corrosion inhibitor includes an organic corrosion inhibitor and a metal corrosion inhibitor in a weight ratio of 15 to 20:1, the organic corrosion inhibitor is composed of a monobasic acid, a dibasic acid, a polybasic acid, and an aromatic organic acid salt, and the metal corrosion inhibitor is one or more of benzotriazole, toluene triazole, and sodium mercaptobenzothiazole.

[0005] Preferably, the cooling medium consists of ethylene glycol, propylene glycol and deionized water.

[0006] Preferably, the pH adjuster is one or more of sodium hydroxide, EDTA-4 sodium, EDTA-2 sodium, monoethanolamine, and triethanolamine.

[0007] Preferably, the hard water stabilizer is one or more of hydrolyzed polymaleic anhydride, sodium polypropylene, phosphate compounds, condensates of amines and ethylene oxide, ethylene oxide / ethylene oxide homopolymers, methyl ethers, glycol ethers, and polyesters.

[0008] Preferably, the defoamer is polyether-modified silicone, and the preparation method thereof is: Step a, dissolving an imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and performing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is (4-5):2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 400-600; Step b, taking the polyether, hydrogen-containing silicone oil with a hydrogen content of 0.3%, and chloroplatinic acid, mixing, stirring, passing inert gas, heating to 100-110° C., reacting for 1 h, and obtaining the defoaming agent, wherein the weight ratio of the polyether to the hydrogen-containing silicone oil is 1-2:1, and the weight percentage of the chloroplatinic acid in the system is 30 ppm.

[0009] Preferably, the dye is a water-based light-fast dye.

[0010] The present invention also provides a method for preparing the engine cooling system replacement medium, comprising the following steps: Step 1: Weigh each component according to the formula; Step 2: Add ethylene glycol and propylene glycol into a mixing container and stir evenly; Step 3: add an organic corrosion inhibitor, a metal corrosion inhibitor, a hard water stabilizer in sequence, and add deionized water accounting for 95% of the total amount of deionized water, stir evenly, and measure the freezing point; Step 4: Add pH adjuster, add remaining 5% deionized water, and stir for 30-40 min; Step 5. Add defoamer, stir for 5 to 10 minutes, then add dye, stir evenly and set aside.

[0011] The present invention also provides an application of the engine cooling system medium exchanger in the cooling system of a fuel engine and a hybrid power engine.

[0012] The present invention includes at least the following beneficial effects: the engine cooling system replacement medium described in the present invention has the advantages of environmental protection, multi-metal corrosion protection, high temperature resistance, etc., has good heat transfer, heat dissipation and cooling effects, is well compatible with the coolant, and is compounded with organic corrosion inhibitors and metal corrosion inhibitors, has good corrosion inhibition effects, and can meet the requirements for replacement fluids in fuel engine and new energy hybrid cooling systems.

[0013] Other advantages, objectives and features of the present invention will be embodied in part through the following description, and in part will be understood by those skilled in the art through study and practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is the freezing point and volume fraction ratio diagram of ethylene glycol and propylene glycol. DETAILED DESCRIPTION

[0015] The present invention is further described in detail below in conjunction with the accompanying drawings and specific embodiments so that those skilled in the art can implement the invention with reference to the description.

[0016] It should be understood that the terms such as “having”, “including” and “comprising” used herein do not exclude the existence or addition of one or more other elements or combinations thereof.

[0017] It should be noted that the experimental methods described in the following embodiments are conventional methods unless otherwise specified, and the reagents and materials can be obtained from commercial sources unless otherwise specified; in the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "set" should be understood in a broad sense, for example, they can be fixedly connected, set, or detachably connected, set, or connected and set in one piece. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood in specific circumstances. The orientation or position relationship indicated by the terms "lateral", "longitudinal", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc. is based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation of the present invention.

[0018] The present invention provides an engine cooling system replacement medium, which includes the following components by weight percentage: cooling medium 85-95%, corrosion inhibitor 1-5%, pH regulator 0.4-1.0%, hard water stabilizer 0.01-0.1%, defoamer 0.01-0.04%, colorant 0.001-0.01%; wherein the corrosion inhibitor includes an organic corrosion inhibitor and a metal corrosion inhibitor with a weight ratio of 15-20:1, the organic corrosion inhibitor is composed of a monobasic acid, a dibasic acid, a polybasic acid, and an aromatic organic acid salt, and the metal corrosion inhibitor is one or more of benzotriazole, methyl benzotriazole, and sodium mercaptobenzothiazole. In this technical solution, the engine cooling system replacement medium mainly includes corrosion inhibitor, pH regulator, stabilizer, defoamer, colorant, etc., wherein the corrosion inhibitor is the most important additive. The use conditions of the corrosion inhibitor have high selectivity, different media have different corrosion inhibitors, and the corrosion inhibitor to be selected will also change completely. Corrosion inhibitors suitable for specific systems can only be used after screening and rigorous evaluation in simulation tests. Comprehensive protection of multiple metals is required in the cooling system, so multiple corrosion inhibitors need to be selected and compounded. In this technical solution, organic corrosion inhibitors are compounded with metal corrosion inhibitors, which can provide comprehensive protection for multiple metals, and are non-toxic, with good corrosion inhibition effects, meeting the use requirements of the cooling system. The use of pH regulators can maintain a certain pH value for the changer medium during use. The use of hard water stabilizers can avoid problems such as deposition of corrosion inhibitors due to different hardnesses of softened water in different places. The colorant can give the changer medium a striking color, making it easier to observe external pipelines and determine the location of leaks.

[0019] In another technical solution, the cooling medium is composed of ethylene glycol, propylene glycol and deionized water. In this technical solution, the cooling medium-water is the main body of the coolant. Water has associated molecules. When water is heated, it consumes heat to dissociate the associated molecules, so that the temperature of the water increases. Water has a large specific heat and is suitable for use as a heat transfer medium for engine coolant. Ethylene glycol and propylene glycol have the characteristics of lowering the freezing point, high boiling point, moderate viscosity, non-flammability, and good chemical stability. Figure 1 From the freezing point and volume fraction ratio diagram of ethylene glycol and propylene glycol, it can be seen that with the cooling medium (freezing point of -40°C) as the base liquid, the volume ratio of ethylene glycol to propylene glycol is between 50% and 55%. According to the mixing density with deionized water, the total mass percentage is about 55%, of which 38.5% is ethylene glycol, 16.5% is propylene glycol, and the rest is deionized water, to prepare the base liquid.

[0020] In another technical solution, the pH regulator is one or more of sodium hydroxide, sodium EDTA-4, sodium EDTA-2, monoethanolamine, and triethanolamine.

[0021] In another technical solution, the hard water stabilizer is one or more of hydrolyzed polymaleic anhydride, sodium polypropylene, phosphate compounds, condensation products of amine and ethylene oxide, ethylene oxide / ethylene oxide homopolymer, methyl ether, ethylene glycol ether, and polyester.

[0022] In another technical solution, the defoamer is polyether-modified silicone, and the preparation method thereof is: Step a, dissolving an imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and performing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is (4-5):2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 400-600; Step b, take the polyether and hydrogen-containing silicone oil with a hydrogen content of 0.3%, chloroplatinic acid, mix, stir, pass inert gas, heat to 100~110℃, react for 1h, and obtain the defoamer, wherein the weight ratio of polyether to hydrogen-containing silicone oil is 1~2:1, and the weight percentage of chloroplatinic acid in the system is 30 ppm. The defoamer prepared in this technical scheme introduces the imide structure into the polyether to improve the high temperature resistance and acid, alkali and salt resistance, so that the final defoamer has excellent high temperature resistance and acid, alkali and salt resistance. The prepared polyether is combined with hydrogen-containing silicone oil to prepare Si-C type polyether modified silicone, which can not only effectively improve the stability and defoaming and anti-foaming properties of the defoamer under high pH and high temperature conditions, but also will not interfere with the film-forming process of the corrosion inhibitor on the metal surface, and has a certain synergistic promotion effect on the corrosion inhibition effect of the corrosion inhibitor.

[0023] In another technical solution, the dye is a water-based sun-fast dye.

[0024] The present invention also provides a method for preparing the engine cooling system replacement medium, comprising the following steps: Step 1: Weigh each component according to the formula; Step 2: Add ethylene glycol and propylene glycol into a mixing container and stir evenly; Step 3: add an organic corrosion inhibitor, a metal corrosion inhibitor, a hard water stabilizer in sequence, and add deionized water accounting for 95% of the total amount of deionized water, stir evenly, and measure the freezing point; Step 4: Add pH adjuster, add remaining 5% deionized water, and stir for 30-40 min; Step 5. Add defoamer, stir for 5 to 10 minutes, then add dye, stir evenly and set aside.

[0025] The present invention also provides an application of the engine cooling system medium exchanger in the cooling system of a fuel engine and a hybrid power engine.

[0026] Example 1 A medium for replacing an engine cooling system comprises the following components by weight percentage: 36.88% ethylene glycol, 15.8% propylene glycol, 1% isooctanoic acid, 0.2% heptanoic acid, 0.2% sebacic acid, 0.2% citric acid, 0.8% sodium benzoate, 0.2% benzotriazole, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% commercially available polyether defoamer, 0.001% fluorescent yellow, and the balance is deionized water.

[0027] The production process of the commercially available polyether defoamer is as follows: pentaerythritol and KOH are mixed and placed in a reaction kettle, wherein the amount of KOH used accounts for 0.3% of the weight of pentaerythritol, heated to 60-80°C, vacuumed, filled with nitrogen, heated to 120-130°C, ethylene oxide and propylene oxide in a weight ratio of 1:1 are added to the system, reacted for 6 hours, the product is neutralized with acid, filtered, and the molecular weight of the final product is 400.

[0028] The preparation method of the above engine cooling system replacement medium is as follows: Step 1: Weigh each component according to the formula; Step 2: Add ethylene glycol and propylene glycol into a mixing container and stir evenly; Step 3: add an organic corrosion inhibitor, a metal corrosion inhibitor, a hard water stabilizer in sequence, and add deionized water accounting for 95% of the total amount of deionized water, stir evenly, and measure the freezing point; Step 4: Add pH adjuster, add remaining 5% deionized water, and stir for 30 minutes; Step 5. Add defoamer, stir for 10 minutes, then add dye, stir evenly and set aside.

[0029] Example 2 The difference from Example 1 is that the polyether-modified polyorganosiloxane disclosed in Example 1 of the invention patent CN111072974A is used as the defoaming agent.

[0030] Example 3 The difference from Example 1 is that a self-made polyether is used as a defoaming agent. The preparation method of the polyether is as follows: dissolving imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and causing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is 4:2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 500.

[0031] Example 4 A medium for replacing an engine cooling system comprises the following components by weight percentage: 36.88% ethylene glycol, 15.8% propylene glycol, 1% isooctanoic acid, 0.2% heptanoic acid, 0.2% sebacic acid, 0.2% citric acid, 0.8% sodium benzoate, 0.2% benzotriazole, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% polyether modified silicone, 0.001% blue-resistant, and the balance is deionized water.

[0032] The preparation process of the polyether-modified silicone is as follows: dissolving imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and performing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is 4:2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 500; Step b, taking the polyether, hydrogen-containing silicone oil with a hydrogen content of 0.3%, and chloroplatinic acid, mixing, stirring, passing inert gas, heating to 100° C., reacting for 1 h, and obtaining the defoaming agent, wherein the weight ratio of the polyether to the hydrogen-containing silicone oil is 1.5:1, and the weight percentage of the chloroplatinic acid in the system is 30 ppm.

[0033] The preparation method of the above engine cooling system replacement medium is as follows: Step 1: Weigh each component according to the formula; Step 2: Add ethylene glycol and propylene glycol into a mixing container and stir evenly; Step 3: add an organic corrosion inhibitor, a metal corrosion inhibitor, a hard water stabilizer in sequence, and add deionized water accounting for 95% of the total amount of deionized water, stir evenly, and measure the freezing point; Step 4: Add pH adjuster, add remaining 5% deionized water, and stir for 30 minutes; Step 5. Add defoamer, stir for 10 minutes, then add dye, stir evenly and set aside.

[0034] Example 5 A medium for replacing an engine cooling system comprises the following components, measured by weight percentage: 38% ethylene glycol, 16% propylene glycol, 2% octanoic acid, 0.2% heptanoic acid, 0.2% suberic acid, 0.2% cinnamic acid, 0.8% sodium benzoate, 0.2% methylbenzotriazole, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% polyether modified silicone, 0.001% fluorescent yellow, and the balance is deionized water.

[0035] The preparation process of the polyether-modified silicone is as follows: dissolving imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and performing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is 5:2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 600; Step b, taking the polyether, hydrogen-containing silicone oil with a hydrogen content of 0.3%, and chloroplatinic acid, mixing, stirring, passing inert gas, heating to 110° C., reacting for 1 h, and obtaining the defoaming agent, wherein the weight ratio of the polyether to the hydrogen-containing silicone oil is 2:1, and the weight percentage of the chloroplatinic acid in the system is 30 ppm.

[0036] The preparation method of the above engine cooling system replacement medium is the same as that of Example 4.

[0037] Example 6 A medium for replacing an engine cooling system comprises the following components, measured by weight percentage: 35% ethylene glycol, 18% propylene glycol, 2% butyric acid, 0.2% nonanoic acid, 0.2% glutaric acid, 0.2% carboxybenzoic acid, 0.8% sodium benzoate, 0.2% sodium mercaptobenzothiazole, 0.4% sodium EDTA-4, 0.05% sodium polypropylene, 0.02% polyether modified silicone, 0.001% blue-resistant, and the balance is deionized water.

[0038] The preparation process of the polyether-modified silicone is as follows: dissolving imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and performing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is 4.5:2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 400; Step b, taking the polyether, hydrogen-containing silicone oil with a hydrogen content of 0.3%, and chloroplatinic acid, mixing, stirring, passing inert gas, heating to 110° C., reacting for 1 h, and obtaining the defoaming agent, wherein the weight ratio of the polyether to the hydrogen-containing silicone oil is 1:1, and the weight percentage of the chloroplatinic acid in the system is 30 ppm.

[0039] The preparation method of the above engine cooling system replacement medium is the same as that of Example 4.

[0040] Comparative Example 1 The difference from Example 1 is that the engine cooling system replacement medium does not contain dibasic acid, that is, it includes the following components by weight percentage: 36.88% ethylene glycol, 15.8% propylene glycol, 1% isooctanoic acid, 0.3% heptanoic acid, 0.3% citric acid, 0.8% sodium benzoate, 0.2% benzotriazole, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% commercially available polyether defoamer, 0.001% fluorescent yellow, and the balance is deionized water.

[0041] Comparative Example 2 The difference from Example 1 is that the engine cooling system replacement medium does not contain polyacid, that is, it includes the following components by weight percentage: 36.88% ethylene glycol, 15.8% propylene glycol, 1% isooctanoic acid, 0.3% heptanoic acid, 0.3% sebacic acid, 0.8% sodium benzoate, 0.2% benzotriazole, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% commercially available polyether defoamer, 0.001% fluorescent yellow, and the balance is deionized water.

[0042] Comparative Example 3 The difference from Example 1 is that the engine cooling system replacement medium does not contain aromatic organic acid salts, that is, it includes the following components by weight percentage: 36.88% ethylene glycol, 15.8% propylene glycol, 1.5% isooctanoic acid, 0.4% heptanoic acid, 0.4% sebacic acid, 0.2% benzotriazole, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% commercially available polyether defoamer, 0.001% fluorescent yellow, and the balance is deionized water.

[0043] Comparative Example 4 The difference from Example 1 is that inorganic corrosion inhibitor is used instead of metal corrosion inhibitor in the engine cooling system replacement medium, that is, it includes the following components by weight percentage: 36.88% ethylene glycol, 15.8% propylene glycol, 1% isooctanoic acid, 0.2% heptanoic acid, 0.2% sebacic acid, 0.2% citric acid, 0.8% sodium benzoate, 0.2% sodium nitrate, 0.5% sodium hydroxide, 0.1% hydrolyzed polymaleic anhydride, 0.01% commercially available polyether defoamer, 0.001% fluorescent yellow, and the balance is deionized water.

[0044] Corrosion inhibition effect test The test method adopts a glassware corrosion test, and the pH value of the engine cooling system exchange medium in Examples 1 to 4 and Comparative Examples 1 to 3 is adjusted to 9.5, and then added to glassware respectively, and a certain weight of copper sheet, brass sheet, cast iron sheet, cast aluminum sheet, steel sheet, and solder sheet are added to the glassware, and placed in a constant temperature bath, the temperature is controlled at 88°C ± 2°C, the experimental time is set to 336 h, and the mass loss of each metal sheet is measured. The results are shown in Table 1. When the mass loss of each metal sheet is less than the quality index, it means that the corrosion result of the metal meets the quality index requirement.

[0045] Table 1 Quality index mg Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Copper: ±10 8.2 8.5 8.9 6.3 14.9 13.2 8.4 10.1 Brass: ±10 7.0 7.2 7.6 7.0 25.1 15.3 9.6 9.5 Cast iron: ±30 6.5 7.7 10.8 6.1 30.6 17.1 16.2 15.8 Cast aluminum: ±30 8.4 13.9 12.5 7.6 34.8 30.6 22.3 20.0 Steel: ±10 7.0 8.1 6.9 5.9 10.1 12.5 8.8 7.2 Solder: ±10 8.6 9.5 8.1 7.7 8.9 9.5 12.1 10.9 The results show that the engine cooling system replacement medium in Examples 1 to 4 has the best corrosion inhibition effect on each metal. The corrosion inhibitors in Examples 1 to 4 are the same, and organic corrosion inhibitors and metal corrosion inhibitors are compounded. The organic corrosion inhibitors are prepared by dibasic acid, polybasic acid and aromatic organic acid salts, which finally make the corrosion inhibition effect on each metal better. However, there is no dibasic acid in the corrosion inhibitor in Comparative Example 1, and there is no polybasic acid in the corrosion inhibitor in Comparative Example 2. The corrosion inhibition effect on copper, iron, aluminum and steel is not up to standard; there is no aromatic organic acid salt in the corrosion inhibitor in Comparative Example 3, and the corrosion inhibition effect is limited, and solder fails to meet the requirements. In Comparative Example 4, an inorganic corrosion inhibitor sodium nitrate is used instead of a metal corrosion inhibitor, and it is compounded with an organic corrosion inhibitor. First, sodium nitrate is toxic and explosive, and there are safety hazards. In addition, it is compounded as an inorganic corrosion inhibitor with the organic corrosion inhibitor in the present invention, and the corrosion inhibition effect on copper and tin is not ideal. The comparison results show that the best corrosion inhibition effect can be achieved only when dibasic acid, polybasic acid and aromatic organic acid salt are compounded with metal corrosion inhibitor as in the present invention.

[0046] In addition, the defoaming agents used in Examples 1 to 3 are different from those used in Example 4. Comparison of the four shows that the degree of metal loss in Examples 1 to 3 is significantly greater than that in Example 4. This is because the defoaming agents in Examples 1 to 3 affect the film-forming properties and corrosion inhibition effect of the corrosion inhibitor when the pH value is 9.5, while the defoaming agent used in Example 4 has a certain synergistic promoting effect on the corrosion inhibition effect of the corrosion inhibitor under high pH conditions.

[0047] Defoaming and antifoaming effect test Take 50 mL of the engine cooling system replacement medium in Examples 1 to 6 and place them in stoppered measuring cylinders, shake them up and down 10 times at a speed of 2 times / s, and record the time when the foam drops to 60 mL, which is the defoaming time. Add 100 mL of the engine cooling system replacement medium in Examples 1 to 6 into the measuring cylinder, bubble with nitrogen, control the nitrogen flow rate to 3 L / min, and record the time when the foam height reaches the scale mark of 200 mL, which is the defoaming time. The results are shown in Table 2.

[0048] Table 2 Defoaming time / s Anti-foam time / min Example 1 7.5 44.8 Example 2 6.8 48.1 Example 3 6.6 43.5 Example 4 5.8 52.3 Example 5 6.0 51.6 Example 6 6.1 51.5 The results show that among the defoamers used in various examples, the defoaming and antifoaming effects of Examples 4 to 6 are better than those of Examples 1 to 3, proving that the defoamers prepared in Examples 4 to 6 introduce the imide structure into the polyether to improve the high temperature resistance and acid, alkali and salt resistance, so that the final defoamer has excellent high temperature resistance and acid, alkali and salt resistance. The prepared polyether is combined with hydrogen-containing silicone oil to prepare Si-C type polyether modified silicone, which effectively improves the stability and defoaming and antifoaming properties of the defoamer.

[0049] Comprehensive performance test The engine cooling system replacement medium prepared in Example 1 was subjected to a comprehensive performance test, and the test results are shown in Table 3. The results show that the engine cooling system replacement medium in Example 1 of the present invention can meet the quality index requirements of the replacement fluid of the fuel engine and the new energy hybrid cooling system.

[0050] Table 3 Test Project Quality indicators Example 1 Test methods Appearance No sediment and suspended matter No obvious change in fluorescent yellow, no sediment or suspended matter Appendix D to GB 29743.1 <![CDATA[Density (20 °C) / (kg / cm 3 )]]> ≥1.065 1.069 SH / T 0068 Freezing point / ℃ ≤-40 -42 SH / T 0090 Boiling point / ℃ ≥108 140 SH / T 0089 pH 7.5-11.0 8.1 SH / T 0069 Chlorine content / (mg / kg) ≤25 10 SH / T 0621 Ash content (mass fraction) / % ≤2.5 0.81 SH / T 0067 Impact on automotive organic coatings No impact No impact SH / T 0084 Although the embodiments of the present invention have been disclosed as above, they are not limited to the applications listed in the specification and the implementation modes, and they can be fully applied to various fields suitable for the present invention. For those familiar with the art, additional modifications can be easily implemented. Therefore, without departing from the general concept defined by the claims and the scope of equivalents, the present invention is not limited to the specific details and the illustrations shown and described herein.

Claims

1. Engine cooling system replacement medium, characterized in that: The invention comprises the following components by weight percentage: 85-95% cooling medium, 1-5% corrosion inhibitor, 0.4-1.0% pH adjuster, 0.01-0.1% hard water stabilizer, 0.01-0.04% defoamer and 0.001-0.01% dye; wherein the corrosion inhibitor comprises an organic corrosion inhibitor and a metal corrosion inhibitor in a weight ratio of 15-20:1, the organic corrosion inhibitor is composed of a monobasic acid, a dibasic acid, a polybasic acid and an aromatic organic acid salt, and the metal corrosion inhibitor is one or more of benzotriazole, toluene triazole and sodium mercaptobenzothiazole.

2. The engine cooling system replacement medium according to claim 1, characterized in that: The cooling medium consists of ethylene glycol, propylene glycol and deionized water.

3. The engine cooling system replacement medium according to claim 1, characterized in that: The pH regulator is one or more of sodium hydroxide, EDTA-4 sodium, EDTA-2 sodium, monoethanolamine, and triethanolamine.

4. The engine cooling system replacement medium according to claim 1, characterized in that: The hard water stabilizer is one or more of hydrolyzed polymaleic anhydride, polypropylene sodium, phosphate compounds, amine and ethylene oxide condensate, ethylene oxide / ethylene oxide homopolymer, methyl ether, glycol ether, and polyester.

5. The engine cooling system replacement medium according to claim 1, characterized in that: The defoamer is polyether-modified silicone, and its preparation method is as follows: Step a, dissolving an imide in N,N-dimethylacetamide, adding 2-mercaptoethanol and benzoyl peroxide, and performing an addition reaction under 365nm light, wherein the weight ratio of the imide, 2-mercaptoethanol, and benzoyl peroxide is (4-5):2:0.03, pouring the product of the addition reaction into petroleum ether, filtering, and obtaining a polyether with a molecular weight of 400-600; Step b, taking the polyether, hydrogen-containing silicone oil with a hydrogen content of 0.3%, and chloroplatinic acid, mixing, stirring, passing inert gas, heating to 100-110° C., reacting for 1 h, and obtaining the defoaming agent, wherein the weight ratio of the polyether to the hydrogen-containing silicone oil is 1-2:1, and the weight percentage of the chloroplatinic acid in the system is 30 ppm.

6. The engine cooling system replacement medium according to claim 1, characterized in that: The dye is a water-based light-fast dye.

7. The method for preparing the engine cooling system replacement medium according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Weigh each component according to the formula; Step 2: Add ethylene glycol and propylene glycol into a mixing container and stir evenly; Step 3: add organic corrosion inhibitor, metal corrosion inhibitor, hard water stabilizer in sequence, and add deionized water accounting for 95% of the total amount of deionized water, stir evenly, and preliminarily measure the freezing point. If the freezing point reaches the specified index, proceed to the next step. If the freezing point does not reach the specified index, adjust the addition ratio of ethylene glycol and propylene glycol until the requirements are met; Step 4: Add pH adjuster, add remaining 5% deionized water, and stir for 30-40 min; Step 5. Add defoamer, stir for 5 to 10 minutes, then add dye, stir evenly and set aside.

8. Use of the engine cooling system exchange medium according to any one of claims 1 to 6 in the cooling system of a fuel engine and a hybrid engine.

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