A detergent for gasoline engine fuel system and its preparation method and application

Abstract

The present invention relates to the technical field of gasoline additives, and discloses a detergent for a gasoline engine fuel system, a preparation method thereof, and an application thereof. The detergent comprises, by mass, 0 to 70 parts of PEA-1, 15 to 40 parts of PEA-2, 1 to 5 parts of an antioxidant, and 10 to 30 parts of an environmentally friendly solvent. The PEA-1 and PEA-2 each comprise multiple layers of sequentially embedded polyetheramine layers, with a sustained-release layer embedded between two adjacent polyetheramine layers, thereby reducing the problem of oxidation and loss of stability of the detergent due to exposure. The detergent of the present invention can simultaneously clean and inhibit the fuel injection nozzle and intake valve of the fuel intake system of an automobile engine without introducing easily deposited elements, and significantly reduce deposits in the engine combustion chamber, thereby improving fuel economy, reducing tail gas emissions, and improving vehicle power performance.

Description

Technical Field

[0001] The present invention relates to the technical field of gasoline additives, and in particular to a detergent for a gasoline engine fuel system, a preparation method and an application thereof. Background Art

[0002] Gasoline detergents are gasoline additives with cleaning, dispersing, antioxidant, and rust-preventing properties. They are used to control deposits in gasoline engine fuel systems and are one of the most effective methods for removing fuel system deposits. While gasoline detergents can control deposits, the carbon deposits flushed from the fuel system can easily be carried into the combustion chamber, increasing the total amount of deposits in the engine's combustion chamber, increasing the engine's compression ratio, and hindering heat dissipation. Furthermore, gasoline detergents currently in use often contain elements such as manganese, phosphorus, calcium, zinc, and magnesium, which form metal oxides and salts at high temperatures. These stable and resistant substances tend to deposit in locations such as the combustion chamber and exhaust pipe. Excessive or severe deposits can cause mechanical interference between the piston top and cylinder head, deactivate or even damage the three-way catalytic converter, ultimately leading to increased fuel consumption, reduced power, and worsening emissions. Therefore, how to both clean and inhibit deposits that are prone to forming in the fuel system and reduce deposits in the engine's combustion chamber has become a key issue for gasoline detergents.

[0003] The latest generation of gasoline detergents utilizes polyetheramines (PEAs). In addition to their typical gasoline detergent properties, they also effectively reduce the formation of combustion chamber deposits (CCDs) due to their inherent ease of decomposition after entering the combustion chamber with gasoline. However, these PEA-based gasoline detergents suffer from poor stability and limited long-term effectiveness. To address this issue, patent publication number CN115806846A proposes a dual-function gasoline detergent base and preparation method. This utilizes a polyetheramine with a specific structure as the primary gasoline detergent raw material. This structure, comprising both a polyetheramine structure and a phenolic structure with antioxidant properties, simultaneously performs both cleaning and antioxidant functions. However, while this gasoline detergent enhances its long-term stability through its antioxidant properties, the phenolic structure responsible for its antioxidant activity is unstable in the presence of acidic substances in deposits, preventing it from maintaining its antioxidant effect over time. Consequently, its overall effectiveness and stability have been suboptimal in practical applications.

[0004] Therefore, there is an urgent need for a detergent with strong stability that can effectively clean and reduce deposits in gasoline engines. Summary of the Invention

[0005] The technical problems to be solved by the present invention are:

[0006] To enhance the long-term effectiveness and stability of existing polyetheramine gasoline detergents, the introduction of functional groups with structures such as phenols has been proposed to impart antioxidant properties to these polyetheramine gasoline detergents. However, gasoline engine deposits contain a large amount of acidic substances, and these phenolic groups are unable to maintain good stability, meaning they lack sustained and stable antioxidant properties. Consequently, the overall treatment effectiveness of these polyetheramine gasoline detergents is suboptimal, and the stability of the gasoline detergents remains relatively weak.

[0007] The technical solution adopted in the present invention is:

[0008] The present invention provides a detergent comprising a composite polyetheramine, wherein the composite polyetheramine comprises at least two monopolyetheramines having a structure such as formula Ia, wherein formula Ia is as follows:

[0009]

[0010] Formula Ia

[0011] Wherein, R1 and R2 are both hydrocarbon groups having 1 to 5 carbon atoms.

[0012] Preferably, the composite polyetheramine includes PEA-1 and PEA-2, and the structural formulas of PEA-1 and PEA-2 are both as Formula Ia.

[0013] Preferably, the composition comprises, by mass, 30 to 70 parts of PEA-1, 15 to 40 parts of PEA-2, 1 to 5 parts of antioxidant and 10 to 30 parts of environmentally friendly solvent.

[0014] Preferably, both the PEA-1 and the PEA-2 include multiple layers of sequentially embedded polyetheramine layers, and a sustained-release layer is embedded between two adjacent polyetheramine layers.

[0015] Preferably, the sustained-release layer is made of one or more of nanographene, carbon nanofiber or carbon nanotube.

[0016] Preferably, a dispersant is further filled between the polyetheramine layer and the sustained-release layer, and the dispersant accounts for 6.5-11.75 wt % of PEA-1 or PEA-2.

[0017] Preferably, the dispersant comprises polyalkylene oxide, polyisobutylene amine and halogenated polyisobutylene succinimide in a mass ratio of 1:0.8-1.2:1-1.8.

[0018] Preferably, the antioxidant is selected from one or more of T501, T502, T531 or T534.

[0019] Preferably, the environmentally friendly solvent is polyoxyethylene dimethyl ether.

[0020] The present invention also provides a method for preparing the above-mentioned detergent, comprising the following steps:

[0021] S1 Preparation of Monopolyetheramine: A polyether raw material and an amination catalyst are taken and subjected to an amination reaction in a hydrogen environment, followed by cooling, filtration, and reduced pressure distillation to obtain a polyetheramine monomer;

[0022] S2 prepares a detergent by mixing and stirring a plurality of polyetheramine monomers, an antioxidant, and an environmentally friendly solvent to obtain a detergent.

[0023] Detergents such as those mentioned above are used in gasoline engines and their fuel systems.

[0024] The present invention also provides a method for applying the detergent as described above, comprising adding the detergent to gasoline, mixing the gasoline, and then refueling the vehicle; wherein the amount of the detergent added is controlled to be 600-800 ppm.

[0025] The technical mechanism and beneficial effects adopted by the present invention are:

[0026] In the present invention, the composite polyetheramine is formed by compounding at least two polyetheramines both having high surface activity. The amino groups in the polyetheramines are electron-rich polar groups with strong polarity. They have a very strong adsorption capacity for sediments and carbon deposits formed in components such as automobile engine fuel nozzles and intake valves, and can be tightly adsorbed on their surfaces. Over time, under the synergistic effect of the amino groups in multiple single polyetheramines, the sediments and carbon deposits are "pulled" by the active molecules, gradually become loose, and are wrapped by the composite polyetheramine in the form of tiny particles, eventually falling off, dispersing into the fuel with the solvent, and finally being discharged from the engine as the fuel burns.

[0027] The use of the detergent in the present invention can not only ensure that it can be fully burned in the engine, but also clean and inhibit the deposits in the fuel system, significantly reducing the deposits in the engine combustion chamber, thereby ensuring that the automobile engine is always in a good working condition, reducing fuel consumption and saving fuel, reducing the emission of harmful gases such as automobile exhaust, and extending the service life of the engine.

[0028] In addition, the various monopolyetheramines in the present invention all adopt a multi-layer structure, and the space skeleton material can be embedded into the monopolyetheramine pellets by alternatingly embedding the polyetheramine layer and the sustained-release layer, so that the polyetheramine has a better sustained-release effect, reducing problems such as oxidative inactivation caused by excessive contact with air, etc., that is, it can maintain a more long-lasting and stable cleaning performance during use.

[0029] Specifically, when using the detergent of the present invention, the detergent is added to automotive gasoline at an amount of 600 to 800 ppm. The detergent acts on various components of the engine as the gasoline enters the engine. Overall, the gasoline detergent provided by the present invention is not only free of easily deposited elements, but also has a significant cleaning effect on fuel system deposits and engine combustion chambers. For example, the cleaning rate of intake valve deposits can be as high as over 97%. It is low-carbon and environmentally friendly, and is beneficial to improving vehicle fuel economy, reducing automobile exhaust emissions, and improving vehicle driving performance. It has good market application prospects. DETAILED DESCRIPTION

[0030] To make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention are described clearly and completely below. Where specific conditions are not specified in the embodiments, conventional conditions or conditions recommended by the manufacturer are used. Where the manufacturer of the reagents or instruments is not specified, all are conventional products that can be purchased commercially.

[0031] The present invention provides a detergent comprising at least two monopolyetheramines having a structure such as Formula Ia, wherein Formula Ia is as follows:

[0032]

[0033] Formula Ia

[0034] Wherein, R1 and R2 are both hydrocarbon groups with carbon atoms of 1 to 5, and the PDI of the monopolyetheramine is 1.1 to 1.2.

[0035] Specifically, the detergent includes, by mass, 30 to 70 parts of PEA-1, 15 to 40 parts of PEA-2, 1 to 5 parts of antioxidant and 10 to 30 parts of environmentally friendly solvent; the antioxidant is selected from one or more of T501, T502, T531 or T534, and the environmentally friendly solvent is polyoxyethylene dimethyl ether.

[0036] In the present invention, the single polyetheramine comprises multiple layers of sequentially embedded polyetheramine layers, a sustained-release layer is embedded between two adjacent polyetheramine layers, and the sustained-release layer adopts one or more of nanographene, carbon nanofiber or carbon nanotube; and 6.5-11.75 wt% of a dispersant is also filled between the polyetheramine layer and the sustained-release layer, and the dispersant comprises polyalkylene oxide, polyisobutylene amine and halogenated polyisobutylene succinimide, so that the single polyetheramine is evenly dispersed to form a polyetheramine layer, thereby reducing the influence of its agglomeration on the cleaning effect.

[0037] The preparation method of the above detergent comprises the following steps:

[0038] S1 Preparation of Monopolyetheramine: 2-amino polyol and an amination catalyst are mixed and placed in an inert gas environment, and an amination reaction is carried out under high temperature and high pressure, followed by cooling, filtration, and reduced pressure distillation to obtain a polyetheramine monomer;

[0039] S2 prepares a detergent by mixing a plurality of polyetheramine monomers, an antioxidant, and an environmentally friendly solvent, and stirring the mixture thoroughly until it becomes transparent to obtain the detergent.

[0040] The detergent can be applied to gasoline engines and their fuel systems. Specifically, the detergent is added to gasoline, mixed, and then refueled. The amount of the detergent added is controlled to be 600-800 ppm.

[0041] <Example>

[0042] Example 1

[0043] (1) Preparation of PEA-1 and PEA-2:

[0044] Take a sufficient amount of 2-aminobutanol, add Raney Ni catalyst, and place it in a hydrogen environment, heat it to about 165°C, pressure it to about 2.5MPa, and react for 4.5h; after the reaction, cool it to about 40°C, filter it, and distill it under reduced pressure for 1.5h to obtain a PEA-1 substrate; take the PEA-1 substrate, dry it and granulate it, then spray the nanographene sustained-release material on the surface of the PEA-1 substrate, and then spray the PEA-1 substrate, repeat 3 times to obtain a PEA-1 with a multilayer structure; before spraying the nanographene sustained-release material or the PEA-1 substrate each time, first immerse it in a dispersed solution, and the dispersed solution is a mixture of polyethylene oxide, polyisobutylene amine and boronated polyisobutylene succinimide at equal mass concentrations.

[0045] A sufficient amount of 2-aminohexanol was added to a Raney Ni catalyst, and the mixture was placed in a hydrogen environment, heated to about 165°C, at a pressure of about 2.5 MPa, and reacted for 4.5 hours. After the reaction, the mixture was cooled to about 40°C, filtered, and distilled under reduced pressure for 1.5 hours to obtain a PEA-2 substrate. The PEA-2 substrate was dried and granulated, and then the surface of the PEA-2 substrate was sprayed with a nanographene sustained-release material, and then the PEA-2 substrate was sprayed, and the process was repeated three times to obtain a PEA-2 with a multilayer structure. Before each spraying with the nanographene sustained-release material or the PEA-2 substrate, the substrate was first immersed in a dispersion solution containing a mixture of polyethylene oxide, polyisobutylene amine, and boronated polyisobutylene succinimide at equal mass concentrations.

[0046] (2) Preparation of detergent:

[0047] By mass fraction, 45 parts of the above-prepared PEA-1 and 35 parts of the above-prepared PEA-2, 1.5 parts of T501 antioxidant and 18.5 parts of polyoxyethylene dimethyl ether solvent were mixed and stirred until the solution became transparent to obtain a detergent.

[0048] Example 2

[0049] (1) Preparation of PEA-1 and PEA-2:

[0050] Take a sufficient amount of 2-aminobutanol, add Raney Ni catalyst, and place it in a hydrogen environment, heat it to about 165°C, pressure it to about 2.5MPa, and react for 4.5h; after the reaction, cool it to about 40°C, filter it, and distill it under reduced pressure for 1.5h to obtain a PEA-1 substrate; take the PEA-1 substrate, dry it and granulate it, then spray the nanographene sustained-release material on the surface of the PEA-1 substrate, and then spray the PEA-1 substrate, repeat 3 times to obtain a PEA-1 with a multilayer structure; before spraying the nanographene sustained-release material or the PEA-1 substrate each time, first immerse it in a dispersed solution, and the dispersed solution is a mixture of polyethylene oxide, polyisobutylene amine and boronated polyisobutylene succinimide at equal mass concentrations.

[0051] A sufficient amount of 2-aminohexanol was added to a Raney Ni catalyst, and the mixture was placed in a hydrogen environment, heated to about 165°C, at a pressure of about 2.5 MPa, and reacted for 4.5 hours. After the reaction, the mixture was cooled to about 40°C, filtered, and distilled under reduced pressure for 1.5 hours to obtain a PEA-2 substrate. The PEA-2 substrate was dried and granulated, and then the surface of the PEA-2 substrate was sprayed with a nanographene sustained-release material, and then the PEA-2 substrate was sprayed, and the process was repeated three times to obtain a PEA-2 with a multilayer structure. Before each spraying with the nanographene sustained-release material or the PEA-2 substrate, the substrate was first immersed in a dispersion solution containing a mixture of polyethylene oxide, polyisobutylene amine, and boronated polyisobutylene succinimide at equal mass concentrations.

[0052] (2) Preparation of detergent:

[0053] By mass fraction, 55 parts of the above-prepared PEA-1 and 25 parts of the above-prepared PEA-2, 1.5 parts of T501 antioxidant and 18.5 parts of polyoxyethylene dimethyl ether solvent were mixed and stirred until the solution became transparent to obtain a detergent.

[0054] Example 3

[0055] (1) Preparation of PEA-1 and PEA-2:

[0056] Take a sufficient amount of 2-aminobutanol, add Raney Ni catalyst, and place it in a hydrogen environment, heat it to about 165°C, the pressure is about 2.5 MPa, and react for 4.5 hours; after the reaction is completed, cool it to about 40°C, filter it, and distill it under reduced pressure for 1.5 hours to obtain a PEA-1 substrate; take the PEA-1 substrate, dry it and granulate it, then spray the nanographene sustained-release material on the surface of the PEA-1 substrate, and then spray the PEA-1 substrate, repeat 3 times to obtain a PEA-1 with a multilayer structure; before spraying the nanographene sustained-release material or the PEA-1 substrate each time, first immerse it in a dispersed solution, and the dispersed solution is a mixture of polypropylene oxide, polyisobutylene amine and boronated polyisobutylene succinimide at equal mass concentrations.

[0057] A sufficient amount of 2-aminohexanol was added to a Raney Ni catalyst, and the mixture was placed in a hydrogen environment, heated to about 165°C, at a pressure of about 2.5 MPa, and reacted for 4.5 hours. After the reaction, the mixture was cooled to about 40°C, filtered, and distilled under reduced pressure for 1.5 hours to obtain a PEA-2 substrate. The PEA-2 substrate was dried and granulated, and then the surface of the PEA-2 substrate was sprayed with a nanographene sustained-release material, and then the PEA-2 substrate was sprayed, and the process was repeated three times to obtain a PEA-2 with a multilayer structure. Before each spraying with the nanographene sustained-release material or the PEA-2 substrate, the substrate was first immersed in a dispersion solution containing a mixture of polyethylene oxide, polyisobutylene amine, and boronated polyisobutylene succinimide at equal mass concentrations.

[0058] (2) Preparation of detergent:

[0059] By mass fraction, 60 parts of the above-prepared PEA-1 and 20 parts of the above-prepared PEA-2, 1.5 parts of T501 antioxidant and 18.5 parts of polyoxyethylene dimethyl ether solvent were mixed and stirred until the solution became transparent to obtain a detergent.

[0060] Example 4

[0061] (1) Preparation of PEA-1 and PEA-2:

[0062] Take a sufficient amount of 2-aminobutanol, add Raney Ni catalyst, and place it in a hydrogen environment, heat it to about 165°C, pressure is about 2.5MPa, and react for 4.5h; after the reaction, cool it to about 40°C, filter it, and distill it under reduced pressure for 1.5h to obtain a PEA-1 substrate; take the PEA-1 substrate, dry it and granulate it, then spray the nanographene sustained-release material on the surface of the PEA-1 substrate, and then spray the PEA-1 substrate, repeat 3 times to obtain a PEA-1 with a multilayer structure; before spraying the nanographene sustained-release material or the PEA-1 substrate each time, first immerse it in a dispersed solution, and the dispersed solution is a mixture of polybutylene oxide, polyisobutylene amine and boronated polyisobutylene succinimide at equal mass concentrations.

[0063] A sufficient amount of 2-aminohexanol was added to a Raney Ni catalyst, and the mixture was placed in a hydrogen environment, heated to about 165°C, at a pressure of about 2.5 MPa, and reacted for 4.5 hours. After the reaction, the mixture was cooled to about 40°C, filtered, and distilled under reduced pressure for 1.5 hours to obtain a PEA-2 substrate. The PEA-2 substrate was dried and granulated, and then the surface of the PEA-2 substrate was sprayed with a nanographene sustained-release material, and then the PEA-2 substrate was sprayed, and the process was repeated three times to obtain a PEA-2 with a multilayer structure. Before each spraying with the nanographene sustained-release material or the PEA-2 substrate, the substrate was first immersed in a dispersion solution containing a mixture of polyethylene oxide, polyisobutylene amine, and boronated polyisobutylene succinimide at equal mass concentrations.

[0064] (2) Preparation of detergent:

[0065] By mass fraction, 65 parts of the above-prepared PEA-1 and 25 parts of the above-prepared PEA-2, 1.5 parts of T501 antioxidant and 18.5 parts of polyoxyethylene dimethyl ether solvent were mixed and stirred until the solution became transparent to obtain a detergent.

[0066] <Test Example>

[0067] Samples: Examples 1-4

[0068] (1) Determination of easily deposited elements

[0069] The above samples were diluted with gasoline octane standard fuel, and the content of easily deposited elements in the automotive gasoline detergent was detected by plasma emission spectrometry. The results are shown in Table 1:

[0070] Table 1 Determination of easily deposited elements in samples

[0071]

[0072] According to Table 1 above, the content of easily deposited elements refers to the limit requirement of Mn content of less than or equal to 2 mg / L in GB 17930-2016 National VI standard motor gasoline. No easily deposited elements were detected in the samples of Examples 1-4, which means that the use of this detergent will not cause poisoning of the three-way catalytic converter.

[0073] (2) Cleanliness performance test

[0074] The samples were added at 600ppm or 800ppm to commercially available No. 92 automotive gasoline (the physical and chemical properties of the oil product meet the national standard requirements of GB17930-2016 "Automotive Gasoline"), and the gasoline detergent was tested for its cleanliness using an L-2 gasoline engine intake valve deposit simulation tester.

[0075] Table 1 Cleaning performance test of samples

[0076]

[0077] Through testing, we found that:

[0078] The detergent sample in Example 1, when added at a dosage of 600 ppm, had a simulated intake valve deposit cleaning rate of 60.98%; and when added at a dosage of 800 ppm, had a simulated intake valve deposit cleaning rate of 69.51%.

[0079] The detergent sample in Example 2, when added at a dosage of 600 ppm, had a simulated intake valve deposit cleaning rate of 63.41%; and when added at a dosage of 800 ppm, had a simulated intake valve deposit cleaning rate of 75.61%.

[0080] The detergent sample in Example 3, when added at a dosage of 600 ppm, had a simulated intake valve deposit cleaning rate of 85.37%; and when added at a dosage of 800 ppm, had a simulated intake valve deposit cleaning rate of 87.80%.

[0081] The detergent sample in Example 4, when added at a dosage of 600 ppm, had a simulated intake valve deposit cleaning rate of 92.68%; and when added at a dosage of 800 ppm, had a simulated intake valve deposit cleaning rate of 97.56%.

[0082] In summary, the detergent prepared using the scheme of the present invention can exert a significant cleaning effect when added to gasoline at a concentration of 600-800 ppm, and can make the automobile engine burn more completely and have higher thermal efficiency, reduce the emission of harmful exhaust substances, be beneficial to energy conservation, emission reduction and environmental protection, and prolong the service life of the engine.

[0083] (3) Stability test

[0084] The samples from Examples 1-4 and a single polyetheramine detergent were placed in a high-temperature environment and allowed to stand for 24 hours. The functional group activity of the detergent samples was then periodically tested. The results showed that the terminal amino groups of the single polyetheramine detergents readily lost activity at high temperatures, resulting in poor stability. However, the detergent samples from Examples 1-4 remained nearly identical to their initial state. This demonstrates that the detergents of the present invention exhibit greater stability than conventional polyetheramine detergents.

[0085] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

Claims

1. A detergent, characterized in that: The composite polyetheramine comprises at least two structures of PEA-1 and PEA-2, and the mass ratio of PEA-1 to PEA-2 is 30-70:15-40; The structural formula of the polyetheramine substrate is selected from Formula Ia, R1 and R2 are both hydrocarbon groups with 1 to 5 carbon atoms, and the degree of polymerization n is 2-6; Formula Ⅰa; The preparation methods of PEA-1 and PEA-2 both include the following steps: A polyether raw material and an amination catalyst are subjected to an amination reaction in a hydrogen environment, followed by cooling, filtration, and reduced-pressure distillation to obtain a polyetheramine substrate; the polyetheramine substrate is dried and granulated, and the surface of the granulated polyetheramine substrate is alternately sprayed with a sustained-release layer material and the polyetheramine substrate before granulation, and the process is repeated multiple times to obtain PEA-1 or PEA-2 having a multilayer structure; Both PEA-1 and PEA-2 include multiple layers of sequentially embedded polyetheramine layers, with a sustained-release layer embedded between two adjacent polyetheramine layers. The sustained-release layer material is one or more of nanographene, carbon nanofiber, or carbon nanotube. In the preparation of PEA-1 and PEA-2, each time before spraying the polyetheramine substrate, it was first placed in a dispersant for impregnation treatment; 6.5-11.75 wt% of a dispersant is also filled between the polyetheramine layer and the sustained-release layer. The dispersant includes polyalkylene oxide, polyisobutylene amine and halogenated polyisobutylene succinimide.

2. The detergent according to claim 1, characterized in that Calculated by mass, it includes 30-70 parts of PEA-1, 15-40 parts of PEA-2, 1-5 parts of antioxidant and 10-30 parts of environmentally friendly solvent.

3. A method for preparing the detergent according to claim 2, characterized in that: The steps include: S1 Preparation of PEA-1 and PEA-2: A polyether raw material and an amination catalyst are subjected to an amination reaction in a hydrogen environment, followed by cooling, filtration, and reduced-pressure distillation to obtain a polyetheramine substrate; the polyetheramine substrate is dried and granulated, and the surface of the granulated polyetheramine substrate is alternately sprayed with a sustained-release layer material and the polyetheramine substrate before granulation, and the process is repeated multiple times to obtain PEA-1 or PEA-2 having a multilayer structure; In the preparation of PEA-1 and PEA-2, each time before spraying the polyetheramine substrate, it was first placed in a dispersant for impregnation treatment; S2 Preparation of detergent: PEA-1, PEA-2, an antioxidant and an environmentally friendly solvent are mixed and stirred to obtain a detergent.

4. A method for using the detergent according to claim 1 or 2, characterized in that: Used in gasoline engines and their fuel systems.

5. The method for applying the detergent according to claim 4, characterized in that: adding the detergent to gasoline, mixing and then refueling the car; Among them, the amount of detergent added is controlled to be 600~800ppm.

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