Engine coolant and deterioration condition prediction method thereof

Abstract

The invention relates to the technical field of engine cooling liquid, in particular to engine cooling liquid and a deterioration condition prediction method thereof.The engine cooling liquid comprises a basic liquid system, an additive system and a charge system, the basic liquid system comprises mixed dihydric alcohol and deionized water, and the ratio of the mixed dihydric alcohol to the deionized water is 1: 1; the additive system comprises an organic acid corrosion inhibitor, a synergistic corrosion inhibitor and an auxiliary agent, the organic acid corrosion inhibitor comprises a core component and auxiliary acids, the core component is selected from sodium benzoate, sodium silicate and mahogany petroleum sulfonate, and the auxiliary acids are selected from sodium alkyl salicylate and sodium isooctyl sulfosuccinate; the same charge is carried by the sodium nitrate electrolyte, the dispersion index can be reduced and the heat conductivity can be improved at high temperature by combining the steric hindrance effect of the mixed dihydric alcohol, magnetic residues are avoided by the superparamagnetic characteristic of the magnetic core, and the antioxidant life of the cooling liquid is prolonged by combining the activated carbon shell to adsorb and degrade products.

Description

Technical Field

[0001] The present invention relates to the technical field of engine coolant, and in particular to an engine coolant and a method for predicting its degradation condition. Background Art

[0002] Engine coolant, a liquid with a low freezing point and a high boiling point, is an essential working medium for the proper functioning of an engine. It primarily removes the substantial heat generated by fuel combustion during engine operation, thereby ensuring stable engine operation at the appropriate temperature. Typically, engine coolant consists of water, antifreeze, and additives. Depending on the composition of the antifreeze, it can be categorized into methanol-ethanol, ethylene glycol, propylene glycol, and non-alcoholic types. Currently, ethylene glycol is the most widely used engine coolant.

[0003] For example, an engine coolant with application number CN201710503060.9 and publication date 20170922 belongs to the field of chemical technology. The invention mixes itaconic acid, anhydrous ethanol, and thioglycolic acid, then adds a catalyst to react. After obtaining the product, the product is concentrated by rotary evaporation to obtain a concentrate. Then, L-ascorbic acid and benzoic acid are mixed, sulfuric acid solution and ice water are added in sequence, and the mixture is reacted and filtered to obtain a filtrate. Ethylene glycol, filtrate, concentrate, and additives are then heated and mixed, and finally naturally cooled to obtain an engine coolant. The coolant obtained by the invention has good cooling performance, good storage stability and rust resistance, effectively extending the service life of the coolant and providing good protection for the engine.

[0004] For example, an engine coolant with application number CN200410009214.1 and authorization announcement date 20060517 is characterized in that it is composed of 1000 parts of ethylene glycol, 500-1500 parts of deionized water, 1-5 parts of sodium hydroxide, 3-10 parts of sodium benzoate, 3-8 parts of salicylic acid, 0.5-3 parts of benzotriazole, 5-10 parts of tert-butylbenzoic acid, 1-3 parts of sodium silicate, 5-10 parts of sebacic acid, and 3-8 parts of phthalic acid. , 1-3 parts of polyacrylic acid, 1-3 parts of silicate stabilizer, 3-8 parts of sodium molybdate, 1-5 parts of tolyltriazole and 0.15-0.2 parts of defoaming agent are mixed and stirred to make a coolant. It has excellent inhibitory protection for various metals such as solder, brass, copper, aluminum, cast iron, steel, etc., especially the protection for aluminum is particularly outstanding, with good stability, good hard water solubility, resistance to silicate gel precipitation, slow inhibitor consumption, stable film formation and long life.

[0005] Engine coolant is a key medium for ensuring engine thermal management and must possess comprehensive properties such as antifreeze, corrosion resistance, anti-fouling, and heat conductivity. Traditional ethylene glycol coolants are based on water and ethylene glycol, supplemented with additives such as corrosion inhibitors and defoamers. However, additives in traditional coolants (such as polyacrylic acid) are easily degraded at high temperatures (>85°C), leading to precipitation or uncontrolled foaming. Nanomaterials (such as silicates) are prone to agglomeration due to the lack of charge regulation, reducing heat conduction efficiency. Therefore, it is urgent to design an engine coolant and a method to predict its degradation status to address the above problems. Summary of the Invention

[0006] The object of the present invention is to provide an engine coolant and a method for predicting its degradation condition to address the above-mentioned deficiencies in the prior art.

[0007] In order to achieve the above object, the present invention provides the following technical solutions:

[0008] An engine coolant, comprising a base fluid system, an additive system and a charge system,

[0009] The base liquid system includes mixed diol and deionized water, and the ratio of the mixed diol to the deionized water is 1:1; the mixed diol is a mixture of ethylene glycol and propylene glycol, and the mass ratio of ethylene glycol to propylene glycol is (0.8-1.2):1.

[0010] The additive system includes an organic acid corrosion inhibitor, a synergistic corrosion inhibitor and an auxiliary agent. The organic acid corrosion inhibitor includes a core component and an auxiliary acid. The core components are selected from sodium benzoate, sodium silicate and petroleum sulfonate. The auxiliary acids are selected from sodium alkyl salicylate and sodium isooctyl sulfosuccinate. In the organic acid corrosion inhibitor, the mass proportion of the core component is 0.3-3.0wt%, wherein the mass ratio of sodium benzoate, sodium silicate and petroleum sulfonate is (1-3): (0.5-1): (0.2-0.8); in the auxiliary acids, the mass ratio of sodium alkyl salicylate to sodium isooctyl sulfosuccinate is (1-4): 1, and the total addition amount of the auxiliary acids is 0.01-4.0wt%.

[0011] The synergistic corrosion inhibitor includes two types: an oxidative corrosion inhibitor and a composite synergistic component. The oxidative corrosion inhibitor is selected from molybdate and an azole compound. The composite synergistic component is selected from methyl benzoic acid. The molybdate is sodium molybdate, and its addition amount is 0.1-0.6wt%; the azole compound is sodium benzotriazole or isothiazolinone, and its addition amount is 0.01-0.4wt%; the addition amount of the methyl benzoic acid is 0.01-2.0wt%, and the mass ratio of the methyl benzoic acid to the molybdate is (0.1-0.5):1.

[0012] The auxiliary agent includes three types: a defoamer, a stabilizer, a dye, and a pH regulator. The defoamer is polyethylene glycol siloxane, the stabilizer is a silicate stabilizer and a fluorescent dye, and the pH regulator is triethanolamine. The addition amount of the defoamer polyethylene glycol siloxane is 0.001-0.06wt%; the silicate stabilizer is potassium sodium silicate, and the addition amount is 0.03-0.06wt%; the fluorescent dye is sulforhodamine B or its derivatives, and the addition amount is 0.005-0.02wt%; the addition amount of the triethanolamine is 0.08-1.0wt% to adjust the pH value of the coolant to 8.5-10.5.

[0013] The charge system includes nano-scale magnetic particles and an electrolyte solution. The nano-scale magnetic particles are selected from nano-scale magnetic activated carbon particles. The nano-scale magnetic activated carbon particles include a magnetic core and an activated carbon shell. The magnetic core of the nano-scale magnetic activated carbon particles is Fe3O4, and the magnetic core accounts for 30-60% of the total mass of the particles. The median particle size (D50) of the nano-scale magnetic activated carbon particles is 20-80nm, and the specific surface area is ≥800m 2 / g, the nanoscale magnetic activated carbon particles have a nanoscale particle size of <100nm, the electrolyte solution is used to make the surface of the nanoscale magnetic particles carry the same charge, the electrolyte solution is a sodium nitrate solution with a concentration of 0.4%-1.7%, the concentration of the sodium nitrate solution is 0.6-1.5wt%, and the mass ratio of sodium nitrate to nanoscale magnetic activated carbon particles is (0.2-0.5):1.

[0014] The charge system also includes polyethylene glycol, which has a molecular weight of 2000-6000Da and is added in an amount of 0.1-0.5wt% to enhance the dispersion stability of the particles; the charge system also includes a surface modifier, which is polyacrylic acid (molecular weight 2000-5000Da) or polyvinyl pyrrolidone (PVPK30), which is added in an amount of 0.05-0.3wt% to enhance the dispersion stability of the nanoparticles through steric hindrance effect.

[0015] The magnetic response intensity of the nano-scale magnetic activated carbon particles is correlated with the degree of coolant degradation. When the magnetic field intensity decays to 70% of the initial value, it is determined to be a critical point of degradation.

[0016] A method for predicting engine coolant degradation conditions comprises the following steps:

[0017] Step S1. Real-time monitoring of magnetic response intensity: Measure the magnetic field intensity of nano-scale magnetic activated carbon particles in the coolant by using a Hall sensor or a magnetometer. The initial value is recorded as H0, and the real-time magnetic field intensity H is recorded. tThe sampling frequency of the magnetic field strength is 10-60 seconds / time, and the measurement location is the preset monitoring point of the engine coolant circulation pipeline. At the same time, the measurement of the magnetic response intensity needs to be carried out at the engine operating temperature, and the temperature compensation algorithm is used to eliminate the interference of thermal fluctuations. The algorithm formula is:

[0018] H' t =H t ×[1+α(T t -T0)]

[0019] Where α is the temperature coefficient α=0.01-0.03 / ℃, T t is the real-time temperature, T0 is the initial calibration temperature, T0 = 25 ° C, H' t is the magnetic field intensity after temperature compensation, H t is the magnetic field strength measured in real time;

[0020] Step S2. Calculate the attenuation rate of the magnetic response intensity: Calculate the attenuation rate according to the formula, which is as follows:

[0021] η=(H0-H t ) / H0×100%

[0022] When η≥30%, it is determined that the coolant has reached the critical point of degradation;

[0023] Step S3. Correlate degradation signals with an early warning mechanism: Set up an early warning mechanism that uses a graded alarm. The vehicle-mounted ECU compares the attenuation rate data with a preset threshold value η ≥ 30%. If the threshold is exceeded, a warning prompt is triggered on the instrument panel or mobile terminal. The specific situation is as follows:

[0024] η=30%-40%, set as level 1 warning, prompting the user to check the coolant status;

[0025] If η>40%, it is set to Level 2 warning, which forcibly limits the engine power output and recommends replacing the coolant immediately;

[0026] At the same time, when issuing an early warning, the degradation judgment result is corrected by combining the coolant pH value and turbidity data.

[0027] In the above technical solution, the present invention provides an engine coolant and a method for predicting its degradation condition, which has the following beneficial effects:

[0028] (1) The present invention uses sodium nitrate electrolyte to carry the same charge, combined with the steric hindrance effect of mixed diols, to reduce the dispersion index and improve thermal conductivity at high temperatures. The superparamagnetic properties of the magnetic core avoid magnetic residue, combined with the activated carbon shell to adsorb degradation products, thereby extending the anti-oxidation life of the coolant.

[0029] (2) The nano-scale magnetic activated carbon particles of the present invention are combined with a charge system to maintain the dispersion stability of the particles through electrostatic repulsion and steric hindrance effects. The magnetic field intensity decay rate is strongly correlated with the degree of coolant deterioration. The combination of magnetic, pH, and turbidity parameters reduces the misjudgment rate from 20% of traditional single parameter monitoring to <5%, thereby improving the accuracy of predicting the deterioration condition of the engine coolant. Compared with traditional detection methods, the maintenance response time is greatly shortened and the replacement cycle is extended.

[0030] (3) Through systematic innovation, the present invention breaks through the bottlenecks of uneven corrosion inhibition, high-temperature instability and lack of degradation monitoring of traditional coolants, and achieves long-term corrosion protection, intelligent early warning and low maintenance costs. It is suitable for high-power engines and harsh working conditions. The comprehensive performance leads the industry standard, and the low-toxicity formula design reduces the overall cost, and has strong environmental and economic advantages. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments. Obviously, the drawings described below are only some embodiments described in the present invention. For ordinary technicians in this field, other drawings can also be obtained based on these drawings.

[0032] Figure 1 A schematic diagram of a basic fluid composition table provided for an embodiment of an engine coolant and a method for predicting its degradation condition according to the present invention.

[0033] Figure 2 A schematic diagram of an organic acid corrosion inhibitor composition table provided in an embodiment of an engine coolant and a method for predicting its degradation condition according to the present invention.

[0034] Figure 3 A schematic diagram of a table of synergistic corrosion inhibitor compositions provided in an embodiment of an engine coolant and a method for predicting its degradation condition according to the present invention.

[0035] Figure 4 A schematic diagram of an auxiliary agent composition table provided in an embodiment of an engine coolant and a method for predicting its degradation condition according to the present invention.

[0036] Figure 5 A schematic diagram of a charge system composition table provided for an embodiment of an engine coolant and a method for predicting its degradation condition according to the present invention.

[0037] Figure 6 A method flow chart is provided for an embodiment of a method for predicting engine coolant and its degradation condition according to the present invention. DETAILED DESCRIPTION

[0038] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0039] like Figure 1-5 As shown, an embodiment of the present invention provides an engine coolant, comprising a base fluid system, an additive system and a charge system.

[0040] The base liquid system includes mixed diol and deionized water, and the ratio of the mixed diol to the deionized water is 1:1; the mixed diol is a mixture of ethylene glycol and propylene glycol, and the mass ratio of ethylene glycol to propylene glycol is (0.8-1.2):1.

[0041] The additive system includes an organic acid corrosion inhibitor, a synergistic corrosion inhibitor and an auxiliary agent. The organic acid corrosion inhibitor includes a core component and an auxiliary acid. The core components are selected from sodium benzoate, sodium silicate and petroleum sulfonate. The auxiliary acids are selected from sodium alkyl salicylate and sodium isooctyl sulfosuccinate. In the organic acid corrosion inhibitor, the mass proportion of the core component is 0.3-3.0wt%, wherein the mass ratio of sodium benzoate, sodium silicate and petroleum sulfonate is (1-3): (0.5-1): (0.2-0.8); in the auxiliary acids, the mass ratio of sodium alkyl salicylate to sodium isooctyl sulfosuccinate is (1-4): 1, and the total addition amount of the auxiliary acids is 0.01-4.0wt%.

[0042] The synergistic corrosion inhibitor includes two types: an oxidative corrosion inhibitor and a composite synergistic component. The oxidative corrosion inhibitor is selected from molybdate and an azole compound. The composite synergistic component is selected from methyl benzoic acid. The molybdate is sodium molybdate, and its addition amount is 0.1-0.6wt%; the azole compound is sodium benzotriazole or isothiazolinone, and its addition amount is 0.01-0.4wt%; the addition amount of the methyl benzoic acid is 0.01-2.0wt%, and the mass ratio of the methyl benzoic acid to the molybdate is (0.1-0.5):1.

[0043] The auxiliary agent includes three types: a defoamer, a stabilizer, a dye, and a pH regulator. The defoamer is polyethylene glycol siloxane, the stabilizer is a silicate stabilizer and a fluorescent dye, and the pH regulator is triethanolamine. The addition amount of the defoamer polyethylene glycol siloxane is 0.001-0.06wt%; the silicate stabilizer is potassium sodium silicate, and the addition amount is 0.03-0.06wt%; the fluorescent dye is sulforhodamine B or its derivatives, and the addition amount is 0.005-0.02wt%; the addition amount of the triethanolamine is 0.08-1.0wt% to adjust the pH value of the coolant to 8.5-10.5.

[0044] The charge system includes nano-scale magnetic particles and an electrolyte solution. The nano-scale magnetic particles are selected from nano-scale magnetic activated carbon particles. The nano-scale magnetic activated carbon particles include a magnetic core and an activated carbon shell. The magnetic core of the nano-scale magnetic activated carbon particles is Fe3O4, and the magnetic core accounts for 30-60% of the total mass of the particles. The median particle size (D50) of the nano-scale magnetic activated carbon particles is 20-80nm, and the specific surface area is ≥800m 2 / g, the nanoscale magnetic activated carbon particles have a nanoscale particle size of <100nm, the electrolyte solution is used to make the surface of the nanoscale magnetic particles carry the same charge, the electrolyte solution is a sodium nitrate solution with a concentration of 0.4%-1.7%, the concentration of the sodium nitrate solution is 0.6-1.5wt%, and the mass ratio of sodium nitrate to nanoscale magnetic activated carbon particles is (0.2-0.5):1.

[0045] The charge system also includes polyethylene glycol, which has a molecular weight of 2000-6000Da and is added in an amount of 0.1-0.5wt% to enhance the dispersion stability of the particles; the charge system also includes a surface modifier, which is polyacrylic acid (molecular weight 2000-5000Da) or polyvinyl pyrrolidone (PVPK30), which is added in an amount of 0.05-0.3wt% to enhance the dispersion stability of the nanoparticles through steric hindrance effect.

[0046] The magnetic response intensity of the nano-scale magnetic activated carbon particles is correlated with the degree of coolant degradation. When the magnetic field intensity decays to 70% of the initial value, it is determined to be a critical point of degradation.

[0047] A method for predicting engine coolant degradation conditions, such as Figure 6 As shown, the following steps are included:

[0048] Step S1. Real-time monitoring of magnetic response intensity: Measure the magnetic field intensity of nano-scale magnetic activated carbon particles in the coolant by using a Hall sensor or a magnetometer. The initial value is recorded as H0, and the real-time magnetic field intensity H is recorded. t The sampling frequency of the magnetic field strength is 10-60 seconds / time, and the measurement location is the preset monitoring point of the engine coolant circulation pipeline. At the same time, the measurement of the magnetic response intensity needs to be carried out at the engine operating temperature, and the temperature compensation algorithm is used to eliminate the interference of thermal fluctuations. The algorithm formula is:

[0049] H' t =H t ×[1+α(T t -T0)]

[0050] Where α is the temperature coefficient α=0.01-0.03 / ℃, T t is the real-time temperature, T0 is the initial calibration temperature, T0 = 25 ° C, H' tis the magnetic field intensity after temperature compensation, H t is the magnetic field strength measured in real time;

[0051] Step S2. Calculate the attenuation rate of the magnetic response intensity: Calculate the attenuation rate according to the formula, which is as follows:

[0052] η=(H0-H t ) / H0×100%

[0053] When η≥30%, it is determined that the coolant has reached the critical point of degradation;

[0054] Step S3. Correlate degradation signals with an early warning mechanism: Set up an early warning mechanism that uses a graded alarm. The vehicle-mounted ECU compares the attenuation rate data with a preset threshold value η ≥ 30%. If the threshold is exceeded, a warning prompt is triggered on the instrument panel or mobile terminal. The specific situation is as follows:

[0055] η=30%-40%, set as level 1 warning, prompting the user to check the coolant status;

[0056] If η>40%, it is set to Level 2 warning, which forcibly limits the engine power output and recommends replacing the coolant immediately;

[0057] At the same time, when warning, the degradation judgment result is corrected by combining the pH value and turbidity data of the coolant. Example 1: Basic formula and multi-metal corrosion inhibition performance verification

[0058] Recipe composition:

[0059] Base liquid system: ethylene glycol and propylene glycol in a mass ratio of 1:1 (50 wt% each), deionized water 50 wt%;

[0060] Organic acid corrosion inhibitor:

[0061] Core ingredients (1.5 wt%): sodium benzoate: sodium silicate: petroleum sulfonate = 2:0.8:0.5 (mass ratio);

[0062] Auxiliary acids (1.2 wt%): sodium alkyl salicylate: sodium isooctyl sulfosuccinate = 3:1;

[0063] Synergistic corrosion inhibitors:

[0064] Sodium molybdate (0.3 wt%), sodium benzotriazole (0.1 wt%), methyl benzoic acid (0.15 wt%);

[0065] Adjuvants:

[0066] Polyethylene glycol siloxane (0.02 wt%), potassium sodium silicate (0.05 wt%), sulforhodamine B (0.01 wt%), triethanolamine (0.5 wt%);

[0067] Charge system:

[0068] Nano-magnetic activated carbon particles (D50 = 50nm, specific surface area 1000m 2 / g, magnetic core accounts for 50wt%), and the addition amount is 0.8wt%;

[0069] Sodium nitrate solution (1.0 wt%), polyethylene glycol (molecular weight 4000 Da, 0.3 wt%), PVPK30 (0.2 wt%).

[0070] Preparation method:

[0071] A. Mix ethylene glycol and propylene glycol in proportion, add deionized water and stir until homogeneous;

[0072] B. Add organic acid corrosion inhibitor, synergistic corrosion inhibitor and auxiliary agent in sequence, and stir at 60℃ for 2 hours;

[0073] C. Disperse nano-sized magnetic activated carbon particles in sodium nitrate solution, ultrasonicate for 30 minutes, add polyethylene glycol and PVPK30, and mix with the base solution;

[0074] D. Adjust pH to 9.5, filter and bottle.

[0075] Performance testing:

[0076] Corrosion rate (ASTM D1384): Aluminum corrosion rate 0.015g / m 2 , cast iron corrosion rate 0.04mm / a;

[0077] Magnetic field decay rate: η = 28% after 100,000 km, no warning triggered;

[0078] Turbidity change rate: After aging for 2000 hours, the turbidity increased by 18%, which is lower than the threshold (20%).

[0079] Example 2: High-temperature stability and early warning mechanism verification

[0080] Recipe composition:

[0081] Base liquid system: ethylene glycol to propylene glycol mass ratio 1.2:1 (ethylene glycol 54.5wt%, propylene glycol 45.5wt%), deionized water 50wt%;

[0082] Organic acid corrosion inhibitor:

[0083] Core ingredients (3.0 wt%): sodium benzoate: sodium silicate: petroleum sulfonate = 3:1:0.8;

[0084] Auxiliary acids (4.0 wt%): sodium alkyl salicylate: sodium isooctyl sulfosuccinate = 4:1;

[0085] Synergistic corrosion inhibitors:

[0086] Sodium molybdate (0.6 wt%), isothiazolinone (0.4 wt%), methyl benzoic acid (0.3 wt%);

[0087] Charge system:

[0088] Nano-magnetic activated carbon particles (D50 = 80nm, specific surface area 850m 2 / g, magnetic core accounts for 60wt%), and the addition amount is 1.2wt%;

[0089] Sodium nitrate solution (1.5 wt%), polyacrylic acid (molecular weight 5000 Da, 0.3 wt%).

[0090] Degradation prediction method:

[0091] A. Real-time monitoring: magnetometer sampling frequency 30 seconds / time, temperature compensation coefficient α=0.02 / ℃;

[0092] B. Warning trigger:

[0093] When η=35% (corresponding to copper corrosion weight loss of 0.09 mg / cm 2 ), triggering a first-level warning and prompting users to check;

[0094] When η=45% (turbidity change rate 25%), the engine power is forced to be limited to 70%.

[0095] High temperature test (120℃ / 2000 hours):

[0096] Magnetic attenuation rate: η = 32%, correlation coefficient R with actual degradation degree (corrosion inhibitor consumption) 2 =0.94;

[0097] Gel precipitation amount: <0.01wt%.

[0098] Example 3: Low-cost environmentally friendly formula

[0099] Recipe composition:

[0100] Base liquid system: ethylene glycol to propylene glycol mass ratio 0.8:1 (ethylene glycol 44.4wt%, propylene glycol 55.6wt%), deionized water 50wt%;

[0101] Organic acid corrosion inhibitor:

[0102] Core ingredients (0.3wt%): sodium benzoate: sodium silicate: petroleum sulfonate = 1:0.5:0.2;

[0103] Auxiliary acids (0.01 wt%): sodium alkyl salicylate: sodium isooctyl sulfosuccinate = 1:1;

[0104] Charge system:

[0105] Nano-magnetic activated carbon particles (D50 = 20nm, specific surface area 1200m 2 / g, magnetic core accounts for 30wt%), and the addition amount is 0.5wt%;

[0106] Sodium nitrate solution (0.6 wt%), polyethylene glycol (molecular weight 2000 Da, 0.1 wt%).

[0107] Environmental advantages:

[0108] A. Nitrite replacement: Triethanolamine (0.08 wt%) was used to adjust pH to avoid the carcinogenic risk of nitrite.

[0109] B. Adsorption performance: Magnetic activated carbon adsorbs acidic products (adsorption capacity ≥ 15 mg / g), reducing the frequency of corrosion inhibitor replenishment by 30%.

[0110] Measured data:

[0111] pH stability: pH value is maintained at 9.0-10.2 during the cycle from -30℃ to 120℃;

[0112] Cost comparison: formula cost is reduced by 22%.

[0113] Example 4: Verification of adaptability to extreme working conditions

[0114] Recipe composition:

[0115] Charge system: nano-magnetic activated carbon particles (D50 = 30nm, specific surface area 1500m 2 / g), added in an amount of 1.0wt%;

[0116] Electrolyte solution: sodium nitrate to particle mass ratio 0.5:1, sodium nitrate concentration 1.7wt%;

[0117] Surface modifier: PVPK30 (0.3 wt%) + polyethylene glycol (0.5 wt%).

[0118] Extreme Testing:

[0119] A. Low temperature -40℃: no crystallization, viscosity ≤50mPa·s (ASTMD2983);

[0120] B. High pressure cycle (2.5 MPa): Magnetic particle dispersion stability D50 change rate <5%;

[0121] C. Magnetic signal calibration: error rate after temperature compensation ≤ 3% (traditional conductivity method error 15%).

[0122] Early warning response:

[0123] When η=30%, the degradation critical point was accurately determined by combining the pH value (decreased to 8.6) and turbidity (increased by 22%) data, with an error rate of <3%.

[0124] The following table can be obtained by comparing the above four embodiments:

[0125]

[0126]

[0127] As can be seen from the above table, if cost and environmental protection are prioritized, Example 3 is the best choice (cost reduction of 22% + no nitrite); if the focus is on high-temperature conditions, Example 2 is more suitable (high-temperature stability is fully verified), Example 1 is recommended for basic performance balance, and Example 4 is the best comprehensive choice.

[0128] The above description is merely illustrative of certain exemplary embodiments of the present invention. It goes without saying that those skilled in the art will be able to modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the above drawings and description are illustrative in nature and should not be construed as limiting the scope of protection of the claims.

Claims

1. An engine coolant comprising a base fluid system, an additive system, and a charge system, characterized in that: The base liquid system includes mixed glycol and deionized water, and the ratio of mixed glycol to deionized water is 1:1; The additive system includes an organic acid corrosion inhibitor, a synergistic corrosion inhibitor and an auxiliary agent. The organic acid corrosion inhibitor includes a core component and an auxiliary acid. The core component is selected from sodium benzoate, sodium silicate and petroleum sulfonate. The auxiliary acid is selected from sodium alkyl salicylate and sodium isooctyl sulfosuccinate. The synergistic corrosion inhibitor includes an oxidative corrosion inhibitor and a composite synergistic component. The oxidative corrosion inhibitor is selected from molybdate and azole compounds. The composite synergistic component is methyl benzoic acid. The auxiliary agent includes a defoamer, a stabilizer, a dye and a pH adjuster. The defoamer is selected from polyethylene glycol siloxane. The stabilizer is selected from silicate stabilizer and fluorescent dye. The pH adjuster is triethanolamine. The charge system includes nanoscale magnetic particles and an electrolyte solution. The nanoscale magnetic particles are selected from nanoscale magnetic activated carbon particles. The nanoscale magnetic activated carbon particles include a magnetic core and an activated carbon shell. The nanoscale magnetic activated carbon particles have a nanoscale particle size of <100 nm. The electrolyte solution is used to make the surface of the nanoscale magnetic particles carry the same charge. The electrolyte solution is selected from a sodium nitrate solution with a concentration of 0.4%-1.7%.

2. The method for predicting engine coolant and its degradation condition according to claim 1, characterized in that: The mixed diol is a mixture of ethylene glycol and propylene glycol, and the mass ratio of ethylene glycol to propylene glycol is (0.8-1.2):

1.

3. The method for predicting engine coolant and its degradation condition according to claim 1, characterized in that: In the organic acid corrosion inhibitor, the mass proportion of the core component is 0.3-3.0wt%, among which the mass ratio of sodium benzoate, sodium silicate and petroleum sulfonate is (1-3): (0.5-1): (0.2-0.8); in the auxiliary acids, the mass ratio of sodium alkyl salicylate to sodium isooctyl sulfosuccinate is (1-4): 1, and the total addition amount of the auxiliary acids is 0.01-4.0wt%.

4. The method for predicting engine coolant and its degradation condition according to claim 1, characterized in that: The molybdate is sodium molybdate, and its addition amount is 0.1-0.6wt%; the azole compound is sodium benzotriazole or isothiazolinone, and its addition amount is 0.01-0.4wt%; the addition amount of methyl benzoic acid is 0.01-2.0wt%, and the mass ratio of methyl benzoic acid to molybdate is (0.1-0.5):

1.

5. The method for predicting engine coolant and its degradation condition according to claim 1, characterized in that: The defoaming agent polyethylene glycol siloxane is added in an amount of 0.001-0.06wt%; the silicate stabilizer is potassium sodium silicate, and its addition amount is 0.03-0.06wt%; the fluorescent dye is sulforhodamine B or its derivatives, and its addition amount is 0.005-0.02wt%; the triethanolamine is added in an amount of 0.08-1.0wt% to adjust the pH value of the coolant to 8.5-10.

5.

6. The engine coolant and its degradation condition prediction method according to claim 1, characterized in that: The magnetic core of the nano-scale magnetic activated carbon particles is Fe3O4, and the magnetic core accounts for 30-60% of the total mass of the particles; the median particle size (D50) of the nano-scale magnetic activated carbon particles is 20-80nm, and the specific surface area is ≥800m 2 / g.

7. The engine coolant and its degradation condition prediction method according to claim 1, characterized in that: The concentration of the sodium nitrate solution is 0.6-1.5 wt %, and the mass ratio of sodium nitrate to nano-scale magnetic activated carbon particles is (0.2-0.5):

1.

8. The engine coolant and its degradation condition prediction method according to claim 1, characterized in that: The charge system also includes polyethylene glycol, which has a molecular weight of 2000-6000Da and is added in an amount of 0.1-0.5wt% to enhance the dispersion stability of the particles; the charge system also includes a surface modifier, which is polyacrylic acid (molecular weight 2000-5000Da) or polyvinyl pyrrolidone (PVPK30), which is added in an amount of 0.05-0.3wt% to enhance the dispersion stability of the nanoparticles through steric hindrance effect.

9. The engine coolant and its degradation condition prediction method according to claim 1, characterized in that: The magnetic response intensity of the nano-scale magnetic activated carbon particles is correlated with the degree of coolant degradation. When the magnetic field intensity decays to 70% of the initial value, it is determined to be a critical point of degradation.

10. A method for predicting engine coolant degradation, characterized in that: The following steps are involved: Step S1. Real-time monitoring of magnetic response intensity: Measure the magnetic field intensity of nano-scale magnetic activated carbon particles in the coolant by using a Hall sensor or a magnetometer. The initial value is recorded as H0, and the real-time magnetic field intensity H is recorded. t The sampling frequency of the magnetic field strength is 10-60 seconds / time, and the measurement location is the preset monitoring point of the engine coolant circulation pipeline. At the same time, the measurement of the magnetic response intensity needs to be carried out at the engine operating temperature, and the temperature compensation algorithm is used to eliminate the interference of thermal fluctuations. The algorithm formula is: H’ t =H t ×[1+α(T t -T0)] Where α is the temperature coefficient α=0.01-0.03 / ℃, T t is the real-time temperature, T0 is the initial calibration temperature, T0 = 25 ° C, H' t is the magnetic field intensity after temperature compensation, H t is the magnetic field strength measured in real time; Step S2. Calculate the attenuation rate of the magnetic response intensity: Calculate the attenuation rate according to the formula, which is as follows: η=(H0-H t ) / H0×100% When η≥30%, it is determined that the coolant has reached the critical point of degradation; Step S3. Correlate degradation signals with an early warning mechanism: Set up an early warning mechanism that uses a graded alarm. The vehicle-mounted ECU compares the attenuation rate data with a preset threshold value η ≥ 30%. If the threshold is exceeded, a warning prompt is triggered on the instrument panel or mobile terminal. The specific situation is as follows: η=30%-40%, set as level 1 warning, prompting the user to check the coolant status; If η>40%, it is set to Level 2 warning, which forcibly limits the engine power output and recommends replacing the coolant immediately; At the same time, when issuing an early warning, the degradation judgment result is corrected by combining the coolant pH value and turbidity data.

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