A fuel nozzle cleaner and a method of making the same

Abstract

The present application relates to the technical field of cleaning agent, in particular to a kind of oil nozzle cleaning agent and preparation method thereof.The cleaning agent includes functional reaction product and organic solvent.The functional reaction product is formed by hydrophobic polyether monoamine acylated with trimellitic anhydride to form aromatic amide-biscarboxylic intermediate, then two-step ring-opening addition with glycidol in specific solvent environment, and finally reacted with glycidyl ester to obtain.The organic solvent is composed of aromatic hydrocarbon solvent, propylene glycol mono-n-butyl ether, de-aromatic hydrocarbon solvent and isopropyl alcohol.The preparation method realizes the time sequence cooperation of "adsorption-permeation-peeling-transportation" function through sequential design of molecular structure, effectively removes dense carbon and paint film of engine oil nozzle.The cleaning agent performs excellently in key performances such as cleaning rate, oil injection volume recovery rate and spray cone angle recovery rate, while maintaining good flow consistency and spray stability.

Description

Technical Field

[0001] This invention relates to the field of cleaning agent technology, and in particular to a fuel injector cleaner and its preparation method. Background Technology

[0002] Carbon buildup on fuel injectors is a critical issue affecting engine performance. The deposits typically consist of a dense, cross-linked varnish film formed by the high-temperature oxidation and polymerization of fuel, as well as solid particles such as soot. These deposits not only adhere to precision surfaces such as needle valves and nozzles, but also form complex, hard carbon deposits in the high-temperature recirculation zone, leading to poor fuel injection and atomization, which severely impacts engine power, fuel economy, and emissions.

[0003] Currently, most fuel injector cleaners on the market are simply formulated from various solvents, detergents, and surfactants. These cleaners primarily remove loose, oil-soluble deposits through the dissolving and dispersing effects of the solvents; their mechanism of action is essentially a physical compounding. However, for the dense, cross-linked oxidized carbon deposits and paint films formed on the fuel injector needle valve head, nozzle edges, and high-temperature recirculation zone, these simple compounding systems have limited cleaning efficiency and are unable to achieve deep and thorough removal.

[0004] To improve cleaning effectiveness, some technologies have begun to incorporate detergents such as polyetheramines. These technologies directly mix ordinary polyetheramines with solvents, utilizing the hydrophilic-lipophilic properties of polyetheramines to improve cleaning performance. However, this direct compounding method fails to provide targeted chemical design for the molecular structure of polyetheramines. During the cleaning process, polyetheramine molecules primarily function as dispersants; their interfacial adsorption force with the dense carbon deposit layer is insufficient, making it difficult to effectively wedge into the deposit layers, resulting in weak penetration and stripping capabilities against stubborn oxidized cross-linked layers.

[0005] More importantly, existing technologies generally lack a systematic design for the sequential functions of the "cleaning process." The cleaning process should ideally be a continuous and synergistic process of "adsorption-penetration-stripping-transport." In simple compound systems, the effects of each component are often random and disordered, failing to optimize their function at specific cleaning stages for different structures and morphologies of deposits. This results in existing cleaning agents, while removing deep carbon deposits, often failing to simultaneously restore the injector's flow accuracy and spray quality. Problems such as poor consistency in fuel injection volume, inadequate recovery of the spray cone angle, and even dripping after cleaning occur, making it difficult to meet the stringent requirements of high-performance engines for injector cleanliness and operational stability. Summary of the Invention

[0006] In view of this, the purpose of this invention is to propose a fuel injector cleaner and its preparation method to solve the technical problems of existing fuel injector cleaners having weak adsorption capacity for dense oxidized carbon deposits and cross-linked paint film interfaces, poor interlayer penetration ability, and disordered timing and insufficient coordination of various functional links (adsorption, penetration, stripping, and transport) in the cleaning process, which makes it difficult to simultaneously improve the fuel injection volume recovery rate, spray cone angle recovery rate and cleaning rate after cleaning.

[0007] To achieve the above objectives, the present invention provides a fuel injector cleaner, comprising a functional reaction product and an organic solvent; the functional reaction product is a reaction product obtained by amidation of a hydrophobic polyether monoamine chain end to form an aromatic amide-dicarboxyl structure by trimellitic anhydride, followed by two-step glycidyl ring-opening addition and glycidyl ester ring-opening addition.

[0008] Further, based on the mass fractions of the components used to prepare the functional reaction product, the functional reaction product is prepared from 520-580 parts of hydrophobic polyether monoamine, 160-185 parts of trimellitic anhydride, 230-280 parts of N,N-dimethylacetamide, 56-83 parts of glycidyl ester, 190-245 parts of glycidyl ester, and 220-280 parts of aromatic solvent. The 56-83 parts of glycidyl ester are added in two stages. The first stage involves adding 38-55 parts of glycidyl ester, which undergoes a ring-opening addition reaction with the carboxyl group in the intermediate formed by the hydrophobic polyether monoamine and trimellitic anhydride in the presence of N,N-dimethylacetamide. The second stage involves adding 18-28 parts of glycidyl ester, after which 220-280 parts of aromatic solvent are added to the aforementioned reaction system to convert it into a mixed solvent system, and the ring-opening addition reaction continues. The glycidyl ester is added after the second addition of glycidyl ester and the completion of the reaction.

[0009] Preferably, based on the mass fractions of the organic solvent, the organic solvent comprises 180-220 parts of aromatic solvent, 220-280 parts of propylene glycol mono-n-butyl ether, 180-220 parts of dearomatic solvent and 90-120 parts of isopropanol.

[0010] Preferably, the hydrophobic polyether monoamine has a weight-average molecular weight of 500-700; and the glycidyl ester has an epoxy equivalent of 235-244 g / mol.

[0011] Preferably, when preparing the functional reaction product, 2.5-4.0 parts by weight of triethylamine are added before the first addition of glycidol.

[0012] Preferably, in the preparation of the functional reaction product, the resin solid acid value of the intermediate formed by the hydrophobic polyether monoamine and trimellitic anhydride is 132-150 mgKOH / g, the resin solid acid value of the reaction system after the first addition of glycidyl is 82-96 mgKOH / g, the resin solid acid value of the reaction system after the second addition of glycidyl is 60-68 mgKOH / g, and the resin solid acid value of the reaction system after the addition of glycidyl ester is 6-10 mgKOH / g.

[0013] Preferably, when preparing the functional reaction product, the reaction temperature for the first addition of glycidyl ester is 44-46℃, the reaction temperature for the second addition of glycidyl ester is 57-60℃, the initial temperature for adding glycidyl ester is 94-96℃, and the addition reaction is completed at 106-109℃; after the addition reaction, the volatiles are removed at 100℃ and 10kPa.

[0014] Preferably, the aromatic solvent is Shell's Q7493; and the dearomatic solvent is Exxsol D40.

[0015] Furthermore, the present invention also provides a method for preparing a fuel injector cleaner, comprising the following steps:

[0016] (1) After mixing hydrophobic polyether monoamine and N,N-dimethylacetamide, react with trimellitic anhydride to obtain an intermediate;

[0017] (2) Add triethylamine to the intermediate obtained in step (1), and then add glycidol to carry out the first ring-opening addition reaction;

[0018] (3) Add aromatic solvent to the reaction system obtained in step (2) to change the reaction system from a solvent system dominated by N,N-dimethylacetamide to a mixed solvent system, and then add glycidyl ether to carry out the second ring-opening addition reaction;

[0019] (4) Add glycidyl ester to the reaction system obtained in step (3) to carry out a ring-opening addition reaction, and then remove the volatiles to obtain a desolvated system;

[0020] (5) Add aromatic solvent, propylene glycol monobutyl ether, dearomatic solvent and isopropanol to the desolventizing system obtained in step (4), mix and filter to obtain fuel injector cleaner.

[0021] The beneficial effects of this invention are:

[0022] (1) This invention constructs an aromatic amide-dicarboxyl site by sequentially introducing trimellitic anhydride into the hydrophobic polyether monoamine chain end, and then introducing glycidyl ester stepwise in different solvent environments, finally introducing glycidyl ester at high temperature, thus constructing a sequential functional structure of "low polarity first, then high hydrophobicity". This structure can be designed for the "adsorption-penetration-stripping-transport" of cleaning, realizing the temporal synergy of functional modules and fundamentally overcoming the functional disorder of simple compound systems. Example data show that the cleaning rate of this invention can reach up to 96.1%, the oil spray volume recovery rate can reach up to 95.2%, and the spray cone angle recovery rate can reach up to 94.2%, achieving efficient and simultaneous improvement of the three key indicators.

[0023] (2) The design of this invention effectively enhances the interfacial interaction and interlayer disruption capabilities against dense carbon deposits. The chain-end aromatic amide structure enhances the affinity and adsorption anchoring effect with the oxidized deposit layer; the small-sized, highly polar front structure preferentially formed in a strongly polar solvent environment can effectively wedge into and swell the dense deposit layer; the secondary glycidyl structure that fills the gap after the solvent environment switch enhances the compatibility with organic phase deposits. Finally, the large-volume hydrophobic end structure introduced by high temperature can efficiently encapsulate and transport the stripped deposit fragments, preventing them from redepositing and clogging the nozzle. This synergistic effect results in a high carbon removal rate for the injector after cleaning, and a more thorough restoration of its internal flow channels. This is manifested in a nozzle mass flow rate loss rate as low as 0.9%, a flow deviation of only 1.2% between cylinders, excellent spray consistency (cone angle standard deviation as low as 0.76°), and extremely low drip rate (0.5 drops / min). -1 ). Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0025] Raw material sources and specifications: The hydrophobic polyether monoamine used was Huntsman's JEFFAMINE M-600 hydrophobic polyether monoamine with a weight-average molecular weight of approximately 600; the glycidyl ester used was Hexion's Cardura E10P with an epoxy equivalent of 235-244 g / mol; the aromatic solvent used was Shell's Q7493 type aromatic solvent; the dearomatization solvent used was ExxonMobil's Exxsol D40; trimellitic anhydride was vacuum dried at 80°C for 4 hours before use, and the reaction vessel was dried and purged with dry nitrogen three times before use; the acid values ​​in steps 1 to 4 were all based on resin solids and were determined by conventional potentiometric titration.

[0026] Example 1:

[0027] Step 1: Add 540g of hydrophobic polyether monoamine and 250g of N,N-dimethylacetamide to a dry reaction vessel, stir at 300rpm for 10min to mix evenly and then cool to 20℃. Then, add 173g of trimellitic anhydride in batches over 60min at 20℃, controlling the temperature inside the vessel to not exceed 30℃ during the addition process. After the addition is complete, raise the temperature to 55℃ and hold for 2h, then raise the temperature to 70℃ and hold to obtain the chain-terminated aromatic amidated dicarboxyl intermediate. When the acid value of the resin solid is measured to be 142mgKOH / g, this step is complete.

[0028] Step 2: Cool the intermediate obtained in Step 1 to 45°C, add 3g of triethylamine, stir at 350rpm for 15min, and then add 45g of glycidyl ether dropwise over 30min at 45°C. After the addition is complete, continue the reaction at this temperature. When the acid value of the resin solid is measured to be 90mgKOH / g, this step is complete.

[0029] Step 3: After the reaction in Step 2 is completed, add 250g of aromatic solvent at 50℃ and stir for 20min to change the system from a strongly polar solvent system dominated by N,N-dimethylacetamide to a mixed solvent system containing aromatic solvent. Then raise the temperature to 58℃ and add 22g of glycidyl ether dropwise over 25min, and continue to keep the temperature high for the reaction. When the acid value of the resin solid is measured to be 65mgKOH / g, this step is ended.

[0030] Step 4: Raise the system obtained in Step 3 to 95°C, add 220g of glycidyl ester dropwise over 40min, raise the temperature to 108°C and hold for 40min. Stop the addition reaction when the acid value of the resin solid is measured to be 8mgKOH / g. Then remove the volatiles under reduced pressure at 100°C and 10kPa, restore atmospheric pressure and cool to 55°C.

[0031] Step 5: Keep the solvent removal system obtained in Step 4 at 55°C, and add 200g of aromatic solvent, 250g of propylene glycol monobutyl ether, 200g of dearomatic solvent and 100g of isopropanol in sequence. Stir at 350rpm for 1h, and then filter through a 5μm filter to obtain the fuel injector cleaner.

[0032] Example 2:

[0033] Step 1: Add 520g of hydrophobic polyether monoamine and 230g of N,N-dimethylacetamide to a dry reaction vessel, stir at 300rpm for 10min to mix evenly and then cool to 20℃. Then, add 160g of trimellitic anhydride in batches over 55min at 20℃, controlling the temperature inside the vessel to not exceed 30℃ during the addition process. After the addition is complete, raise the temperature to 55℃ and hold for 2h, then raise the temperature to 70℃ and hold to obtain the intermediate. When the acid value of the resin solid is measured to be 132mgKOH / g, this step is complete.

[0034] Step 2: Cool the intermediate obtained in Step 1 to 44°C, add 2.5g of triethylamine, stir at 350rpm for 15min, and then add 38g of glycidyl ether dropwise over 25min at 44°C. After the addition is complete, continue the reaction at this temperature. When the acid value of the resin solid is measured to be 84mgKOH / g, this step is complete.

[0035] Step 3: After the reaction in Step 2 is completed, add 220g of aromatic solvent at 50℃ and stir for 20min to change the system from a strongly polar solvent system dominated by N,N-dimethylacetamide to a mixed solvent system containing aromatic solvent. Then raise the temperature to 57℃ and add 18g of glycidyl ether dropwise over 20min, and continue to keep the temperature for reaction. When the acid value of the resin solid is measured to be 60mgKOH / g, this step is ended.

[0036] Step 4: Raise the system obtained in Step 3 to 94℃, add 190g of glycidyl ester dropwise over 35min, raise the temperature to 106℃ and hold for 35min. Stop the addition reaction when the acid value of the resin solid is measured to be 10mgKOH / g. Then remove the volatiles under reduced pressure at 100℃ and 10kPa, then restore atmospheric pressure and cool to 55℃.

[0037] Step 5: Keep the solvent removal system obtained in Step 4 at 55°C, and add 180g of aromatic solvent, 220g of propylene glycol mono-n-butyl ether, 180g of dearomatic solvent and 90g of isopropanol in sequence. Stir at 350rpm for 1h, and then filter through a 5μm filter to obtain the fuel injector cleaner.

[0038] Example 3:

[0039] Step 1: Add 580g of hydrophobic polyether monoamine and 280g of N,N-dimethylacetamide to a dry reaction vessel, stir at 300rpm for 10min to mix evenly and then cool to 20℃. Then, add 185g of trimellitic anhydride in batches over 65min at 20℃, controlling the temperature inside the vessel to not exceed 35℃ during the addition process. After the addition is complete, raise the temperature to 55℃ and hold for 2h, then raise it to 72℃ and hold to obtain the intermediate. When the solid acid value of the resin is measured to be 150mgKOH / g, this step is complete.

[0040] Step 2: Cool the intermediate obtained in Step 1 to 46°C, add 4.0 g of triethylamine, stir at 350 rpm for 15 min, and then add 55 g of glycidyl ether dropwise over 35 min at 46°C. After the addition is complete, continue the reaction at this temperature. When the acid value of the resin solid is measured to be 96 mg KOH / g, this step is complete.

[0041] Step 3: After the reaction in Step 2 is completed, add 280g of aromatic solvent at 52℃ and stir for 20min to change the system from a strongly polar solvent system dominated by N,N-dimethylacetamide to a mixed solvent system containing aromatic solvent. Then raise the temperature to 60℃ and add 28g of glycidyl ether dropwise over 30min, and continue to keep the temperature for reaction. When the acid value of the resin solid is measured to be 68mgKOH / g, this step is ended.

[0042] Step 4: Raise the system obtained in Step 3 to 96℃, add 245g of glycidyl ester dropwise over 45min, raise the temperature to 109℃ and hold for 45min. Stop the addition reaction when the acid value of the resin solid is measured to be 6mgKOH / g. Then remove the volatiles under reduced pressure at 100℃ and 10kPa, then restore atmospheric pressure and cool to 55℃.

[0043] Step 5: Keep the solvent removal system obtained in Step 4 at 55°C, and add 220g of aromatic solvent, 280g of propylene glycol mono-n-butyl ether, 220g of dearomatic solvent and 120g of isopropanol in sequence. Stir at 350rpm for 1h, and then filter through a 5μm filter to obtain the fuel injector cleaner.

[0044] Example 4:

[0045] Step 1: Add 540g of hydrophobic polyether monoamine and 260g of N,N-dimethylacetamide to a dry reaction vessel, stir at 300rpm for 10min to mix evenly and then cool to 20℃. Then, add 173g of trimellitic anhydride in batches over 60min at 20℃, controlling the temperature inside the vessel to not exceed 30℃ during the addition process. After the addition is complete, raise the temperature to 55℃ and hold for 2h, then raise the temperature to 70℃ and hold to obtain the intermediate. When the acid value of the resin solid is measured to be 142mgKOH / g, this step is complete.

[0046] Step 2: Cool the intermediate obtained in Step 1 to 45°C, add 3.0 g of triethylamine, stir at 350 rpm for 15 min, and then add 55 g of glycidyl ether dropwise over 30 min at 45°C. After the addition is complete, continue the reaction at this temperature. When the acid value of the resin solid is measured to be 82 mg KOH / g, this step is complete.

[0047] Step 3: After the reaction in Step 2 is completed, add 240g of aromatic solvent at 50℃ and stir for 20min to change the system from a strongly polar solvent system dominated by N,N-dimethylacetamide to a mixed solvent system containing aromatic solvent. Then raise the temperature to 58℃ and add 18g of glycidyl ether dropwise over 20min, and continue to keep the temperature for reaction. When the acid value of the resin solid is measured to be 62mgKOH / g, this step is ended.

[0048] Step 4: Raise the system obtained in Step 3 to 95°C, add 210g of glycidyl ester dropwise over 40min, raise the temperature to 108°C and hold for 40min. Stop the addition reaction when the acid value of the resin solid is measured to be 7mgKOH / g. Then remove the volatiles under reduced pressure at 100°C and 10kPa, restore atmospheric pressure and cool to 55°C.

[0049] Step 5: Keep the solvent removal system obtained in Step 4 at 55°C, and add 200g of aromatic solvent, 260g of propylene glycol mono-n-butyl ether, 190g of aromatic solvent and 100g of isopropanol in sequence. Stir at 350rpm for 1h, and then filter through a 5μm filter to obtain the fuel injector cleaner.

[0050] Example 5:

[0051] Step 1: Add 560g of hydrophobic polyether monoamine and 240g of N,N-dimethylacetamide to a dry reaction vessel, stir at 300rpm for 10min to mix evenly and then cool to 20℃. Then, add 178g of trimellitic anhydride in batches over 60min at 20℃, controlling the temperature inside the vessel to not exceed 32℃ during the addition process. After the addition is complete, raise the temperature to 55℃ and hold for 2h, then raise the temperature to 71℃ and hold to obtain the intermediate. When the acid value of the resin solid is measured to be 146mgKOH / g, this step is complete.

[0052] Step 2: Cool the intermediate obtained in Step 1 to 45°C, add 3.5g of triethylamine, stir at 350rpm for 15min, and then add 40g of glycidyl ether dropwise over 28min at 45°C. After the addition is complete, continue the reaction at this temperature. When the acid value of the resin solid is measured to be 92mgKOH / g, this step is complete.

[0053] Step 3: After the reaction in Step 2 is completed, add 260g of aromatic solvent at 51℃ and stir for 20min to change the system from a strongly polar solvent system dominated by N,N-dimethylacetamide to a mixed solvent system containing aromatic solvent. Then raise the temperature to 59℃ and add 28g of glycidyl ether dropwise over 30min, and continue to keep the temperature for reaction. When the acid value of the resin solid is measured to be 64mgKOH / g, this step is ended.

[0054] Step 4: Raise the system obtained in Step 3 to 95°C, add 230g of glycidyl ester dropwise over 42 minutes, raise the temperature to 108°C and hold for 4 minutes. Stop the addition reaction when the acid value of the resin solid is measured to be 8mgKOH / g. Then remove the volatiles under reduced pressure at 100°C and 10kPa, restore atmospheric pressure and cool to 55°C.

[0055] Step 5: Keep the solvent removal system obtained in Step 4 at 55°C, and add 210g of aromatic solvent, 240g of propylene glycol mono-n-butyl ether, 210g of dearomatic solvent and 110g of isopropanol in sequence. Stir at 350rpm for 1h, and then filter through a 5μm filter to obtain the fuel injector cleaner.

[0056] Comparative Example 1:

[0057] The difference between Comparative Example 1 and Example 1 is that the amount of trimellitic anhydride added in step 1 was changed from 173g to 120g, and an additional 53g of dearomatic solvent was added in step 5 to make up the total formula mass. The other conditions are the same as in Example 1.

[0058] Comparative Example 2:

[0059] The difference between Comparative Example 2 and Example 1 is that in step 2, 45g of glycidol and 22g of glycidol in step 3 are combined to 67g and added dropwise at 45°C; in step 3, no more glycidol is added, and the other conditions are the same as in Example 1.

[0060] Comparative Example 3:

[0061] The difference between Comparative Example 3 and Example 1 is that 220g of glycidyl ester was used instead of 45g of glycidyl ester in step 2, 45g of glycidyl ester was used instead of 220g of glycidyl ester in step 4, and 22g of glycidyl ester was still added in step 3. The other conditions were the same as in Example 1.

[0062] Comparative Example 4:

[0063] The difference between Comparative Example 4 and Example 1 is that 22g of glycidol was added in step 2 and 45g of glycidol was added in step 3. The total amount of glycidol added in the two steps was still 67g, and the other conditions were the same as in Example 1.

[0064] Comparative Example 5:

[0065] The difference between Comparative Example 5 and Example 1 is that 220g of glycidyl ester is not added in step 4, and an additional 220g of dearomatic solvent is added in step 5 to make up the total formula mass. The other conditions are the same as in Example 1.

[0066] Comparative Example 6:

[0067] The difference between Comparative Example 6 and Example 1 is that 250g of N,N-dimethylacetamide was added in step 3 instead of 250g of aromatic solvent, so that both steps 2 and 3 were in a solvent environment dominated by N,N-dimethylacetamide. The other conditions were the same as in Example 1.

[0068] Sample Preparation and Grouping: The injector cleaners prepared in Examples 1-5 and Comparative Examples 1-6 were used as liquid samples. After filtration, they were sealed and allowed to stand at 25°C for 24 hours for later use. Forty-four gasoline engine solenoid valve injector assemblies from the same manufacturer and batch were selected as injector samples. Initial injection quantity, spray cone angle, and dripping were measured according to the flow and spray test principle of GB / T 25363-2010. Injectors with an initial flow deviation of no more than ±2.0% were selected and divided into 11 groups of four. Subsequently, contaminated fuel was prepared according to the basic test fuel requirements in Appendix A of GB19592-2019, and a clogging test was conducted according to GB / T 19230.3-2003. After the mass flow loss rate of each group of nozzles reached 15%-20%, they were used as samples to be cleaned. The cleaning and testing equipment used was an automotive engine electric nozzle cleaning and testing instrument conforming to JT / T 638-2005, with an ultrasonic frequency of 40kHz, ultrasonic power of 300W, cleaning fluid temperature of 50±2℃, system pressure of 300kPa, injection pulse width of 2.5ms, pulse frequency of 10Hz, and a single cycle cleaning time of 20min; 500mL of cleaning fluid was used for each sample. After cleaning, the samples were rinsed with a dearomatic solvent for 30s, dried with 0.30MPa compressed air for 60s, and allowed to stand at room temperature for 30min before subsequent testing. The brass test pieces were made from H62 refined roll-rolled thin plates conforming to GB / T 5231.

[0069] Acid value, kinematic viscosity at 40℃, and closed-cup flash point: Acid value was determined according to GB / T 6743-2008 and expressed as mgKOH / g; kinematic viscosity at 40℃ was determined according to GB / T 265-1988; closed-cup flash point was determined according to the Binsky-Martin closed-cup method according to GB / T 261-2021. Each sample was measured in triplicate, and the arithmetic mean was taken as the result.

[0070] Cleaning capability: As per Appendix A of GB / T 23435-2009. Brass test pieces were made from H62 refined rolled thin plates conforming to GB / T 5231. They were first polished with 180# and 240# sandpaper sequentially, then cleaned sequentially with solvent gasoline, anhydrous ethanol, and acetone, and dried with hot air before use. Standard dirt was prepared as follows: 500g of SF15W / 40 gasoline engine oil and 50g of N660 carbon black were mixed evenly and placed in a 1L wide-mouth bottle. The mixture was aged at 240±5℃ with air circulation for 120h at a flow rate of 8.5±0.5cm / s. Three test pieces were weighed and recorded as m1. The standard dirt was then applied and baked at 230±2℃ for 20min, and the weight was recorded as m2. Test pieces with a dirt mass change within ±5% of the average value were selected as valid test pieces. The effective test pieces were immersed in three separate washing tanks containing 500 mL of the sample to be tested at 80±2℃. After standing for 3 minutes, they were rinsed for 3 minutes, and then rinsed 10 times in 500 mL of distilled water at 80±2℃. After removal, they were dried at 105±2℃ for 30 minutes, cooled to room temperature, and weighed, which was recorded as m3. The cleaning rate was calculated as (m2-m3) / (m2-m1)×100%, and the deviation of the three repeated measurements from the average value should not exceed ±2% of the average value.

[0071] Fuel injection recovery rate, nozzle mass flow rate loss rate, and flow deviation of each cylinder: Fuel injection quantity was measured on the same test bench before, after, and after clogging. Flow rate testing was conducted according to the flow measurement principle of GB / T 25363-2010, combined with the nozzle mass flow rate loss rate evaluation approach of GB / T19230.3-2003. The test fluid temperature was 25±2℃, the system pressure was 300kPa, the injection pulse width was 2.5ms, and the pulse frequency was 10Hz. The cumulative fuel injection quantity of 1000 injections was recorded each time, and each sample was measured three times consecutively. Let the initial average fuel injection quantity be Q0, and the average fuel injection quantity after clogging be Q. d The average fuel injection quantity after cleaning is Q. c The fuel injection quantity recovery rate is calculated according to (Q) c -Q d ) / (Q0-Q d The nozzle mass flow rate loss rate after cleaning is calculated as (Q0 - Q) × 100%. c The flow rate deviation of each cylinder of the four injectors in the same group is calculated as (maximum injection quantity in the same group - minimum injection quantity in the same group) / average injection quantity in the same group × 100%.

[0072] Spray cone angle recovery rate, cone angle standard deviation, and drip rate: Spray testing was conducted on the same injector test bench according to the spray and sealing test principles of GB / T 25363-2010. The test fluid temperature was 25±2℃, the system pressure was 300kPa, the injection pulse width was 2.5ms, and the pulse frequency was 10Hz. Spray images of 20 independent injection cycles were acquired using a backlight imaging system, and the average spray cone angle of each injector was calculated. The initial spray cone angle was set as θ0, and the spray cone angle after clogging was set as θ... d After cleaning, the spray cone angle is θ. c The spray cone angle recovery rate is calculated according to (θ) c -θ d ) / (θ0-θ d The standard deviation of the cone angle of the four injectors in the same group after cleaning was calculated by statistical methods and expressed in °, used to characterize spray consistency; the drip rate was statistically analyzed by the number of droplets in the collection cup within 60 seconds after the injection signal was cut off, expressed in drops·min. -1 express.

[0073] The test results are shown in Table 1.

[0074] Table 1 Performance Test Results

[0075] sample <![CDATA[Acid value / mgKOH·g -1 > <![CDATA[Kinematic viscosity at 40°C / mm 2 ·s -1 > Closed-cup flash point / ℃ Cleaning rate / % Fuel injection quantity recovery rate / % Nozzle mass flow rate loss after cleaning / % Flow deviation of each cylinder / % Spray cone angle recovery rate / % Standard deviation of cone angle / ° <![CDATA[Dripping amount / drop·min -1 > Example 1 4.57 3.64 55.8 94.6 93.6 1.2 1.4 92.1 0.82 0.7 Example 2 5.80 3.21 54.2 89.7 88.4 2.1 2.3 86.8 1.24 1.6 Example 3 3.39 4.08 58.3 95.0 94.1 1.1 1.5 93.0 0.88 0.8 Example 4 3.99 3.71 55.1 92.3 90.7 1.7 1.8 89.0 1.01 1.1 Example 5 4.59 3.86 56.7 96.1 95.2 0.9 1.2 94.2 0.76 0.5 Comparative Example 1 2.06 3.18 54.0 86.7 84.9 2.7 2.8 81.5 1.67 2.3 Comparative Example 2 5.46 3.43 54.7 81.9 81.2 3.5 3.5 77.9 2.02 3.0 Comparative Example 3 6.31 3.06 53.1 76.2 74.6 4.8 4.1 71.1 2.48 4.2 Comparative Example 4 5.08 3.37 54.4 84.2 82.7 3.1 3.1 79.8 1.86 2.7 Comparative Example 5 28.84 2.42 52.0 71.4 69.8 5.6 4.8 66.4 2.93 5.1 Comparative Example 6 5.19 3.34 54.1 83.3 81.6 3.4 3.3 78.6 1.95 2.8

[0076] As shown in Table 1, Examples 1-5 are significantly better than Comparative Examples 1-6 in terms of cleaning rate, fuel injection recovery rate, and spray cone angle recovery rate. They are also significantly lower in terms of nozzle mass flow loss rate, flow deviation of each cylinder, standard deviation of cone angle, and dripping amount after cleaning. This indicates that the present application constructs aromatic amide-dicarboxyl adsorption sites at the hydrophobic polyether monoamine chain end by trimellitic anhydride, and then introduces glycidyl ester in two steps in different solvent environments, and introduces glycidyl ester at high temperature in the later stage to form a large-volume hydrophobic transport structure. This can simultaneously enhance the directional adsorption, interlayer penetration, peeling loosening, and continuous removal of peeling fragments on the surface of the deposited layer, thereby achieving simultaneous improvement of multiple indicators.

[0077] Specifically, Example 5 exhibits the best overall performance, with a cleaning rate of 96.1%, a fuel injection quantity recovery rate of 95.2%, a spray cone angle recovery rate of 94.2%, a nozzle mass flow rate loss rate of only 0.9% after cleaning, a flow rate deviation of 1.2% for each cylinder, a cone angle standard deviation of 0.76°, and a drip rate of only 0.5 drops per minute. -1 This indicates that it can still maintain high flow consistency and spray stability after deep cleaning. Although Example 3 has the highest closed-cup flash point and the lowest acid value, its kinematic viscosity at 40°C is relatively high. The overall balance between front-end penetration and back-end carryover is slightly inferior to that of Example 5, so its overall balance is slightly lower than that of Example 5.

[0078] Although the final acid value of Comparative Example 1 decreased further, this was due to the reduced amount of trimellitic anhydride, which led to a decrease in the number of carboxyl sites that could interact with the chain ends. This did not necessarily mean an enhanced interfacial interaction. Therefore, its cleaning rate and spray recovery rate were still lower than those of the other examples. Comparative Examples 2 and 4 disrupted the temporal division of labor and the relationship between the amounts added in the two-step glycidyl ester process, respectively. This prevented the small polarity penetrating structure in the first stage from fully cooperating with the complementary structure in the second stage. Consequently, their spray recovery rate and spray cone angle recovery rate both decreased significantly. Although Comparative Example 6 retained the two-step glycidyl ester process and the subsequent glycidyl ester, the incomplete transition from a strongly polar solvent to a mixed solvent environment in step 3 resulted in insufficient matching between the active chain ends and the organic deposit phase. As a result, the flow rate deviation and dripping amount in each cylinder remained high after cleaning. Comparative Example 3 introduced large-volume glycidyl ester in advance and placed small-molecule glycidyl ester later, which weakened the front-end wedging penetration ability; Comparative Example 5 further eliminated the rear-end glycidyl ester, resulting in the worst ability to wrap and transport loose carbon deposits. Therefore, its cleaning rate, oil injection recovery rate and spray cone angle recovery rate were the lowest, while its flow loss rate, cone angle standard deviation and dripping amount were the highest.

[0079] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A fuel injector cleaner, characterized in that, Includes functional reaction products and organic solvents; The functional reaction product is a reaction product obtained by amidation of hydrophobic polyether monoamine chain end to form aromatic amide-dicarboxyl structure by trimellitic anhydride, followed by two-step glycidyl ring-opening addition and glycidyl ester ring-opening addition. The functional reaction product is prepared from 520-580 parts of hydrophobic polyether monoamine, 160-185 parts of trimellitic anhydride, 230-280 parts of N,N-dimethylacetamide, 56-83 parts of glycidyl ether, 190-245 parts of glycidyl ether and 220-280 parts of aromatic solvent, based on the mass fractions of the components used in its preparation. The preparation method of the functional reaction product, by mass fraction, includes the following steps: (1) Mix 520-580 parts of hydrophobic polyether monoamine and 230-280 parts of N,N-dimethylacetamide, then add 160-185 parts of trimellitic anhydride to react until the acid value of the resin solid is measured to be 132-150 mg KOH / g, and obtain the intermediate. (2) Add 2.5-4.0 parts by weight of triethylamine to the intermediate obtained in step (1), and then add 38-55 parts of glycidyl ether to carry out the first ring-opening addition reaction until the acid value of the resin solid in the reaction system is measured to be 82-96 mgKOH / g. (3) Add 220-280 parts of aromatic solvent to the reaction system obtained in step (2) to change the reaction system from a solvent system dominated by N,N-dimethylacetamide to a mixed solvent system, and then add 18-28 parts of glycidyl ether to carry out the second ring-opening addition reaction until the acid value of the resin solid in the reaction system is measured to be 60-68 mgKOH / g. (4) Add 190-245 parts of glycidyl ester to the reaction system obtained in step (3) to carry out a ring-opening addition reaction until the acid value of the resin solid in the reaction system is measured to be 6-10 mgKOH / g. Then remove the volatiles at 100℃ and 10kPa to obtain the desolvated system. Based on the mass fractions of the organic solvent, the organic solvent comprises 180-220 parts of aromatic solvent, 220-280 parts of propylene glycol monobutyl ether, 180-220 parts of dearomatic solvent, and 90-120 parts of isopropanol; the hydrophobic polyether monoamine has a weight-average molecular weight of 500-700; and the glycidyl ester has an epoxy equivalent of 235-244 g / mol.

2. The fuel injector cleaner according to claim 1, characterized in that, When preparing the functional reaction product, the reaction temperature for the first addition of glycidyl ester is 44-46℃, the reaction temperature for the second addition of glycidyl ester is 57-60℃, the initial temperature for adding glycidyl ester is 94-96℃, and the addition reaction is completed at 106-109℃; after the addition reaction, the volatiles are removed at 100℃ and 10kPa.

3. The fuel injector cleaner according to claim 1, characterized in that, The aromatic solvent is Shell's Q7493; the dearomatic solvent is Exxsol D40.

4. A method for preparing a fuel injector cleaner according to any one of claims 1-3, characterized in that, By weight, the steps include: (1) Mix 520-580 parts of hydrophobic polyether monoamine and 230-280 parts of N,N-dimethylacetamide, then add 160-185 parts of trimellitic anhydride to react until the acid value of the resin solid is measured to be 132-150 mg KOH / g, and obtain the intermediate. (2) Add 2.5-4.0 parts by weight of triethylamine to the intermediate obtained in step (1), and then add 38-55 parts of glycidyl ether to carry out the first ring-opening addition reaction until the acid value of the resin solid in the reaction system is measured to be 82-96 mgKOH / g. (3) Add 220-280 parts of aromatic solvent to the reaction system obtained in step (2) to change the reaction system from a solvent system dominated by N,N-dimethylacetamide to a mixed solvent system, and then add 18-28 parts of glycidyl ether to carry out the second ring-opening addition reaction until the acid value of the resin solid in the reaction system is measured to be 60-68 mgKOH / g. (4) Add 190-245 parts of glycidyl ester to the reaction system obtained in step (3) to carry out a ring-opening addition reaction until the acid value of the resin solid in the reaction system is measured to be 6-10 mgKOH / g. Then remove the volatiles at 100℃ and 10kPa to obtain the desolvated system. (5) Add the organic solvent to the desolventizing system and filter to obtain the fuel injector cleaner.