High-pressure common-rail oil injection system and method suitable for nano-bubble fuel

Abstract

The invention discloses a high-pressure common rail oil injection system and method suitable for nanobubble fuel, the system comprises a fuel oil tank and a common rail which are connected through a high-pressure pump, an oil supply outlet of the common rail is connected with a three-way electromagnetic valve, and the common rail and the three-way electromagnetic valve are provided with a first loop and a second loop which are communicated with the fuel oil tank respectively; the first loop is connected with a dissolver and a cyclone degasser; the method comprises the steps that nano-bubble fuel oil is pressurized by a high-pressure pump from a fuel oil tank and then conveyed to a common rail, a part of the nano-bubble fuel oil flows out through a first loop and enters a dissolver, and a circulation loop of the dissolver, a pressure limiting valve, a rotational flow degasser, the nano-bubble fuel oil tank and the high-pressure pump is formed; and a part of nano-bubble fuel oil flows to the three-way electromagnetic valve from the oil supply outlet. The dissolver and the cyclone degasser are innovatively integrated in the high-pressure common rail system, gas separated out of circulating fuel oil is effectively removed, air resistance is prevented, and the working stability of the sprayer is guaranteed.

Description

Technical Field

[0001] This invention belongs to the technical field of internal combustion engine fuel injection systems, specifically, it relates to a high-pressure common rail fuel injection system and method suitable for nanobubble fuels. Background Technology

[0002] With the development of the internal combustion engine industry, increasingly higher demands are being placed on fuel injection systems, especially in terms of improving combustion efficiency, reducing emissions, and adapting to new fuels. Traditional high-pressure common rail injection systems, such as... Figure 1 As shown, it mainly includes a fuel tank 10 and a common rail 1 connected via a high-pressure pump 2. The fuel supply outlet 32 ​​of the common rail 1 is connected to a three-way solenoid valve 4, which is further connected to an atomizer 5 to inject fuel into the cylinder 11. The common rail 1 and the three-way solenoid valve 4 are respectively provided with a first circuit 31 and a second circuit 6 connecting the fuel tank 10. Although high-pressure common rail injection systems are widely used in diesel engines and have achieved high injection pressure and flexible injection control, research on fuels with nanobubbles is still lacking.

[0003] Nanobubble fuel, as a novel fuel form, significantly improves fuel atomization quality and combustion characteristics by introducing micro- and nano-scale bubbles into the fuel, thereby increasing combustion efficiency and reducing pollutant emissions. However, the unique physical properties of nanobubble fuel (such as bubble stability, compressibility, and gas-liquid two-phase flow characteristics) pose new challenges to traditional high-pressure common rail systems. For example, in traditional systems, bubbles are prone to coalescence, collapse, or separation during high-pressure delivery and injection, leading to uneven fuel composition and affecting injection stability and combustion consistency. CN 105840289 A provides a common rail injector cooling system, including a fuel tank, a low-pressure fuel pump, a high-pressure fuel pump, a fuel rail, an engine cylinder head, a common rail injector, and an engine cylinder head cover. This system utilizes the fuel medium to directly cool the solenoid valve components, improving the cooling efficiency of the solenoid valve and achieving the effect of unaffected or even improved injection response and operational stability under high injection pressure. While improving stability, it does not solve the vapor resistance problem of nanobubble fuel in the common rail system. CN 201818409 U proposes a high-pressure common rail injection device suitable for various fuels (including biodiesel, methanol, etc.). It achieves optimal injection pressure for different fuels by switching control strategies according to fuel type via an electronic control unit. However, this device is not optimized for the two-phase flow characteristics of nanobubble fuels and cannot effectively prevent the aggregation and precipitation of bubbles under high pressure. Summary of the Invention

[0004] The purpose of this invention is to overcome the deficiencies in the prior art and provide a high-pressure common rail injection system and method suitable for nanobubble fuels.

[0005] The objective of this invention can be achieved through the following technical solutions: The present invention provides a high-pressure common rail injection system suitable for nanobubble fuel. The system includes a fuel tank and a common rail connected by a high-pressure pump. The fuel supply outlet of the common rail is connected to several three-way solenoid valves. The three-way solenoid valves are further connected to a sprayer to inject fuel into the cylinder through the sprayer. The common rail and the three-way solenoid valves are respectively provided with a first circuit and a second circuit connected to the fuel tank. A pressure limiting valve is also provided on the first circuit. The first circuit is also connected in sequence to a dissolver and a cyclone degasser; wherein, the dissolver is used to introduce gas to mix with fuel oil to form a gas-liquid mixture, and the cyclone degasser is used to remove large air bubbles entrained in the gas-liquid mixture.

[0006] In some embodiments of the present invention, the cyclone degasser is integrated into the fuel tank.

[0007] In some embodiments of the present invention, the cylinder is further provided with a spray zone communicating with the sprayer, as well as an air inlet and an exhaust outlet located on both sides of the sprayer.

[0008] In some embodiments of the present invention, the solvent has a cylindrical body, a gas inlet or a circulating fuel inlet at the top end, a nanobubble fuel outlet at the bottom end, a circulating fuel inlet or a gas inlet on the side wall of the top, the circulating fuel inlet being connected to the first loop, and a hollow tank being connected below the gas inlet or the circulating fuel inlet at the top end. The hollow tank is filled with an oleophilic permeable membrane, and the upper part of the side wall of the hollow tank is connected to the circulating fuel inlet or the gas inlet, while the rest of the side wall is sealed. The bottom wall has a plurality of small pores with a diameter of 500nm to 1000nm.

[0009] In some embodiments of the present invention, the nanobubble fuel outlet is connected to a check ball via a spring, and a container is connected below the nanobubble fuel outlet. The container is fitted over the outside of the check ball, and the bottom of the container is open or has a liquid outlet on its bottom wall.

[0010] In some embodiments of the present invention, the oleophilic permeable membrane is formed by combining several cylindrical hollow fiber membranes, and the oleophilic permeable membrane occupies 40-60% of the volume of the hollow tank.

[0011] In some embodiments of the present invention, the method for preparing the hollow fiber membrane includes the following steps: (1) Add N-methylpyrrolidone to the reaction vessel, and slowly add PEG-400 and glycerol while stirring continuously. Add PVDF powder in portions, heat and react to form a transparent and viscous spinning solution. (2) Let the spinning solution prepared in step (1) stand to degas, keep the temperature of the spinning solution at 45-55℃, and use N-methylpyrrolidone / deionized water mixture as core liquid. Then, spin the solution by dry-wet method to obtain wet hollow fiber membrane. (3) Soak the wet hollow fiber membrane obtained in step (2) in deionized water, then soak it in anhydrous ethanol, and dry it to obtain a hollow fiber membrane.

[0012] Furthermore, the molecular weight of the PVDF powder is 400,000 to 600,000.

[0013] In some embodiments of the present invention, the upper end of the shell side wall of the cyclone degasser is provided with a tangential liquid inlet, and the top and bottom of the shell are respectively provided with an exhaust port and a liquid outlet; the exhaust port is connected to an exhaust pipe that penetrates the wall of the fuel tank and is used to guide the separated gas to the outside of the fuel tank.

[0014] In some embodiments of the present invention, the height-to-diameter ratio of the cyclone degasser is 3 to 5.

[0015] Another aspect of the present invention provides a method for high-pressure common rail injection of nanobubble fuel, comprising the following steps: Nanobubble fuel is pressurized from the fuel tank by a high-pressure pump and delivered to the common rail. A portion of the nanobubble fuel flows out through the first circuit and enters the solvent, forming a circulation loop of solvent-pressure relief valve-cyclone degasser-nanobubble fuel tank-high-pressure pump; another portion of the nanobubble fuel flows from the fuel supply outlet to the three-way solenoid valve.

[0016] Furthermore, in the first loop, a portion of the nanobubble fuel flows out through the first loop and enters the solvent through the circulating fuel inlet. It mixes with the gas entering from the gas inlet and flows through the oleophilic permeation membrane in the hollow tank. The resulting gas-liquid mixture flows out from the small hole at the bottom of the hollow tank. The pressure generated when it flows out through the nanobubble fuel outlet pushes open the check ball, allowing the gas-liquid mixture to flow out from both sides of the nanobubble fuel outlet and enter the cyclone degasser through the tangential liquid inlet. Density separation is achieved by using the centrifugal force field. Large bubble gas is discharged through the gas outlet pipe, and the gas-liquid mixture after removing the large bubbles flows into the fuel tank through the liquid outlet. In the fuel supply outlet, when the three-way solenoid valve is activated, a portion of the nanobubble fuel flows from the fuel supply outlet into the sprayer. The fuel, after being atomized by the high pressure of the sprayer, mixes with the air entering through the air inlet in the spray zone, and finally undergoes compression combustion in the cylinder. The exhaust gas after combustion is discharged through the exhaust outlet.

[0017] In some embodiments of the present invention, the three-way solenoid valve adjusts the return oil volume according to the common rail pressure signal.

[0018] Furthermore, when the common rail pressure increases, the three-way solenoid valve opens the second circuit, allowing fuel to return to the fuel tank through the second circuit, thereby reducing the amount of fuel in the common rail and lowering the pressure; when the common rail pressure decreases, the three-way solenoid valve closes the second circuit, while the high-pressure pump continues to supply fuel to the common rail, causing the pressure to rise again.

[0019] In some embodiments of the present invention, the degassing efficiency of the cyclone degasser is not less than 90%, ensuring that the volume fraction of large air bubbles (>1μm) in the fuel returned to the fuel tank is less than 0.5%.

[0020] Compared with the prior art, the present invention has the following outstanding advantages: This invention innovatively integrates a dissolver and a cyclone degasser into a high-pressure common rail system, effectively removing gases released from the circulating fuel, preventing vapor lock, ensuring the stability and accuracy of the sprayer, improving fuel atomization, and enabling the stable application of nanobubble fuel in the high-pressure common rail system, fully leveraging its energy-saving and emission-reduction advantages. Attached Figure Description

[0021] Figure 1 A schematic diagram of a high-pressure common rail injection system suitable for common fuels; Figure 2 A schematic diagram of a high-pressure common rail injection system suitable for nanobubble fuel; Figure 3 This is a schematic diagram of a dissolving apparatus; Figure 4 This is a schematic diagram of the oleophilic permeation membrane in the solvent.

[0022] Drawing number explanation: 1-Common rail; 2-High pressure pump; 31-First circuit; 32-Fuel supply outlet; 4-Three-way solenoid valve; 5-Sprayer; 6-Second circuit; 7-Dissolver; 8-Pressure relief valve; 9-Swirl degasser; 10-Fuel tank; 11-Cylinder; 12-Spray zone; 13-Air inlet; 14-Exhaust gas outlet; 91 - Tangential liquid inlet; 92 - Exhaust port; 93 - Liquid outlet; 94 - Exhaust pipe; 71-Oleophilic permeable membrane; 72-Gas inlet; 73-Check ball; 74-Circulating fuel inlet; 75-Nano bubble fuel outlet; 76-Hollow tank; 77-Body; 78-Container; 79-Spring; 710-Hollow fiber membrane. Detailed Implementation

[0023] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. These embodiments are based on the technical solution of the present invention and provide detailed implementation methods and specific operating procedures. However, the scope of protection of the present invention is not limited to the following embodiments.

[0024] This invention delivers fuel from the fuel tank to a common rail system after being pressurized by a high-pressure pump. Part of the nanobubble fuel in the common rail is sprayed into the engine cylinders via a sprayer, while the other part passes through the common rail circuit, a dissolver, and a pressure-limiting valve before entering a cyclone degasser. In the dissolver, circulating fuel from the common rail circuit flows through an oleophilic permeation membrane. Its core mechanism utilizes the oleophilic properties of the membrane interface and a high-pressure environment to achieve controllable secondary mixing and activation of the gas and liquid phases: the fuel preferentially wets the membrane pores, forcing the gas entering from the gas inlet to be broken into micro- and nano-scale bubbles under high-pressure shearing, which are then uniformly dispersed in the fuel, forming a gas-liquid mixture. This mixture then enters the cyclone degasser through an outlet with a check valve and a tangential liquid inlet for gas-liquid separation. In the cyclone degasser, centrifugal force is used to achieve density separation; large bubbles are thrown towards the central axis region and discharged through the exhaust port, while the fuel, after the removal of large bubbles, returns to the fuel tank through the liquid outlet, thus maintaining the stability and uniformity of the fuel within the tank. This invention effectively solves the stability problem of nanobubble fuel under high pressure, ensuring the reliable operation of the common rail system and improving the overall system efficiency.

[0025] Example 1 1.1 High-Pressure Common Rail Injection System Suitable for Nanobubble Fuel Figure 1 The figure shows a schematic diagram of a high-pressure common rail injection system suitable for ordinary fuels. The system includes a fuel tank 10 and a common rail 1 connected by a high-pressure pump 2. The fuel supply outlet 32 ​​of the common rail 1 is connected to several three-way solenoid valves 4. The three-way solenoid valves 4 are further connected to a sprayer 5 to inject fuel into the cylinder 11 through the sprayer 5. The common rail 1 and the three-way solenoid valves 4 are respectively provided with a first circuit 31 and a second circuit 6 connected to the fuel tank 10. A pressure relief valve 8 is also provided on the first circuit. The cylinder 11 is provided with a spray area 12 communicating with the sprayer 5, as well as an air inlet 13 and an exhaust outlet 14 located on both sides of the sprayer 5.

[0026] Figure 2 This is a schematic diagram of a high-pressure common rail injection system suitable for nanobubble fuels, compared to... Figure 1 The improvements are shown in the figure. The first circuit 31 is also connected in sequence to a dissolver 7 and a cyclone degasser 9; the cyclone degasser 9 is integrated into the fuel tank 10. Furthermore, the upper end of the side wall of the cyclone degasser 9 is provided with a tangential liquid inlet 91, and the top and bottom of the shell are respectively provided with an exhaust port 92 and a liquid outlet 93; the exhaust port 92 is connected to an exhaust pipe 94, which penetrates the wall of the fuel tank 10 and is used to guide the separated gas to the outside of the fuel tank 10; the height-to-diameter ratio of the cyclone degasser is 3 to 5; Combination Figure 3As shown, the dissolver 7 has a cylindrical body 77. The top and bottom of the body 77 are respectively provided with a gas inlet 72 and a nanobubble fuel outlet 75. A circulating fuel inlet 74, connected to the first circuit 31, is provided on the side wall of the top. A hollow tank 76 is connected below the gas inlet 72, for example, by welding to the top wall of the body 77. The hollow tank 76 is filled with an oleophilic permeable membrane 71, accounting for approximately 60% of its volume. The side wall of the hollow tank 76 is connected to... The circulating fuel inlet 74 is connected, with the remaining sidewalls sealed, and the bottom wall has several small holes with a diameter of 500nm to 1000nm. The nanobubble fuel outlet 75 is connected to a check ball 73 via a spring 79, and a container 78 is connected below the nanobubble fuel outlet 75. The container 78 is fitted over the check ball 73, and the bottom of the container 78 is open or has a liquid outlet on its bottom wall. Preferably, the height of the hollow tank 76 is 3 / 5 of the height of the main body 77. Furthermore, the positions of the gas inlet and the circulating fuel inlet are interchangeable. Furthermore, combined with... Figure 4 As shown, the oleophilic permeable membrane 71 is formed by combining several cylindrical hollow fiber membranes 710.

[0027] Furthermore, the three-way solenoid valve 4 adjusts the return fuel volume according to the pressure signal of the common rail 1. Specifically, when the pressure of the common rail 1 increases, the three-way solenoid valve 4 opens the second circuit 6, allowing fuel to return to the fuel tank 10 through the second circuit 6, thereby reducing the amount of fuel in the common rail 1 and lowering the pressure; when the pressure of the common rail 1 decreases, the three-way solenoid valve 4 closes the second circuit 6, while the high-pressure pump 2 continues to supply fuel to the common rail 1, causing the pressure to rise again.

[0028] 1.2 High-Pressure Common Rail Injection Method Applicable to Nanobubble Fuels Using the system described in 1.1 above, combined with Figures 2-3 The method includes the following steps: Nanobubble fuel is pressurized from fuel tank 10 and delivered to common rail 1 by high-pressure pump 2. A portion of the nanobubble fuel flows out through first circuit 31 and enters solvent 7, forming a circulation loop of solvent 7-pressure limiting valve 8-cyclone degasser 9-fuel tank 10-high-pressure pump 2; a portion of the nanobubble fuel flows from fuel supply outlet 32 ​​to three-way solenoid valve 4, wherein: In the first loop 31, a portion of the nanobubble fuel flows out through the first loop 31 and enters the solvent 7 through the circulating fuel inlet 74. It mixes with the gas entering from the gas inlet 72 and flows through the oleophilic permeation membrane 71 inside the hollow tank 76. The resulting gas-liquid mixture flows out from the small hole at the bottom of the hollow tank 76. The pressure generated when it flows out through the nanobubble fuel outlet 75 pushes open the check ball 73, allowing the gas-liquid mixture to bypass the check ball 73 and flow out from the nanobubble fuel outlet 75. After being regulated by the pressure relief valve 8, it enters the cyclone degasser 9 through the tangential liquid inlet 91. The density is separated by the centrifugal force field. The large bubble gas contained therein is discharged through the gas outlet pipe 94. The gas-liquid mixture after the large bubbles are removed flows into the fuel tank 10 through the liquid outlet 93. When the three-way solenoid valve 4 is activated, a portion of the nanobubble fuel flows from the fuel supply outlet 32 ​​into the sprayer 5. The fuel, after being atomized by the high pressure of the sprayer 5, mixes with the air entering through the air inlet 13 in the spray zone 12, and finally undergoes compression combustion in the cylinder 11. The exhaust gas after combustion is discharged through the exhaust outlet 14.

[0029] The method for preparing the hollow fiber membrane mentioned above is a conventional method, which includes the following steps: (1) Add 15.6g of N-methylpyrrolidone to the reaction vessel, and slowly add 1g of PEG-400 and 0.4g of glycerol while stirring continuously. Stir until dissolved, and add a total of 3g of PVDF powder in 3 portions. Heat to 65°C and stir continuously for 7 hours until the PVDF is dissolved to form a transparent and viscous spinning solution; (PVDF powder is Kynar® 720 with a molecular weight of approximately 500,000). (2) The spinning solution prepared in step (1) is allowed to stand for 24 hours to degas, and the temperature of the spinning solution is kept at 50°C. A mixture of N-methylpyrrolidone / deionized water with a volume ratio of 80:20 is used as the core liquid. The spinning solution and the core liquid are extruded from the spinneret at the same time. After passing through a short air gap, the liquid column enters the coagulation bath (deionized water at a temperature of ~30°C) to cause liquid-liquid phase separation of PVDF and solidify to form a porous structure, thus obtaining a wet hollow fiber membrane. (3) Soak the wet hollow fiber membrane obtained in step (2) in deionized water for 24 hours, change the water every 8 hours, then soak it in 30wt% ethanol aqueous solution for 4 hours, then soak it in 50wt% ethanol aqueous solution for 4 hours, and finally soak it in anhydrous ethanol for 4 hours. Place it at room temperature for 3 hours and dry it in an oven at 60℃ for 8 hours to obtain the hollow fiber membrane.

[0030] Example 2 This embodiment uses the high-pressure common rail injection system and method for nanobubble fuel from Embodiment 1. The system is installed on a diesel engine, wherein the nanobubble concentration of the nanobubble fuel in the fuel tank 10 is 1×10⁻⁶. 8 The sprayer has a flow rate of 1000 ml / mL, a height-to-diameter ratio of 4 for the cyclone degasser, and after the system is running, the common rail pressure stabilizes at 160±10 MPa. The sprayer works normally without shaking or shutting down.

[0031] Example 3 The high-pressure common rail injection system and method for nanobubble fuel used in this embodiment are the same as those in Embodiment 2, except that the height-to-diameter ratio of the cyclone degasser is 3.

[0032] Example 4 The high-pressure common rail injection system and method for nanobubble fuel used in this embodiment are the same as those in Embodiment 2, except that the height-to-diameter ratio of the cyclone degasser is 5.

[0033] Example 5 The high-pressure common rail injection system and method for nanobubble fuel used in this embodiment are the same as those in Embodiment 2, except that the height-to-diameter ratio of the cyclone degasser is 2.

[0034] Example 6 The high-pressure common rail injection system and method for nanobubble fuel used in this embodiment are the same as those in Embodiment 2, except that the height-to-diameter ratio of the cyclone degasser is 5.5.

[0035] Performance testing The above embodiments 2-6 were tested and analyzed. The purpose of this test was to verify the effectiveness of the system on key performance parameters. All tests were conducted under steady-state conditions on the engine bench. The specific data are listed in Table 1.

[0036] I. Test method for volume fraction of large air bubbles (>1μm) After the system is running stably, fuel samples are periodically collected at the liquid outlet of the cyclone degasser using a dedicated syringe. A dynamic image analyzer is used to analyze the fuel samples in real time. An instrument recognition threshold is set, and the percentage of the total volume of bubbles larger than 1 μm in diameter relative to the total sample volume is calculated. This measurement is repeated multiple times, and the arithmetic mean is taken as the large bubble volume fraction under that operating condition.

[0037] II. Degassing Efficiency Test Method Sampling points: Inlet: Tangential liquid inlet of the cyclone degasser; Outlet: Liquid outlet of the cyclone degasser.

[0038] Measurement: A high-precision particulate counter is used to simultaneously measure the number concentration (number of bubbles / mL) of fuel bubbles per unit volume at the inlet and outlet.

[0039] Calculation: Degassing efficiency refers to the ability of a cyclone degasser to remove bubbles. The calculation formula is: Degassing efficiency = (1 - outlet bubble number concentration / inlet bubble number concentration) × 100%.

[0040] III. Test Methods for Improving Engine Effective Thermal Efficiency Benchmark Test: A standard high-pressure common rail system was installed on a specified model diesel engine. Under standard environmental conditions (ambient temperature 25±2°C, relative humidity 50%±10%), the engine was stabilized at a specific operating point (speed 1500 rpm, torque 200 N·m). After the engine stabilized, the engine output power (P) was measured using a dynamometer with an accuracy of at least 0.5 class. 基准 (Unit: kW), and simultaneously use a high-precision fuel flow meter to measure fuel consumption mass flow rate (m³). 基准 (Unit: kg / h)

[0041] System testing for this invention: Under identical engine conditions, environmental conditions, and operating points, the engine's fuel system was switched to the system described in this invention (ensuring the fuel tank contained fuel from the same batch with the same nano-bubble concentration). After the system stabilized, the engine output power (P) was measured at the same location using the same instruments. 本发明 ) and fuel consumption mass flow rate (m 本发明 ).

[0042] calculate: Effective thermal efficiency calculation: Effective thermal efficiency η = [Output power (P) / (Fuel consumption mass flow rate (m³) × Fuel lower heating value (Q)] LHV ))]× 100%; Calculate the effective thermal efficiency η of the two systems respectively. In this embodiment, the lower heating value of the fuel used for calculation is based on the national standard GB 19147-2016 "Diesel for Vehicles", which is 43.0 MJ / kg.

[0043] The thermal efficiency of the reference system is denoted as η. 基准 The thermal efficiency of the system in this invention is denoted as η. 本发明 ; Effective thermal efficiency improvement = (η) 本发明 - η 基准 ) / η 基准 ]× 100% IV. Carbon Emission Reduction Test Method Benchmark test: Under the same operating conditions for testing the effective thermal efficiency of the engine, use an opacity meter to measure the carbon emissions (in mg / m³) of the engine exhaust when the system is assembled.

[0044] System testing for this invention: At the same operating point, the carbon soot emission value of the exhaust gas after assembling the system of this invention was measured. The calculation is as follows: Calculate the percentage reduction in carbon soot emissions: Carbon soot emission reduction rate = (Emission value of ordinary system - Emission value of system of this invention) / Emission value of ordinary system × 100%.

[0045] Table 1 As shown in Table 1, Examples 2-4 enable more stable application of nanobubble fuel in high-pressure common rail systems, fully leveraging its energy-saving and emission-reduction advantages. Compared to Example 2, Examples 5-6 alter the aspect ratio of the cyclone degasser to varying degrees, resulting in a significant decrease in degassing efficiency and potentially causing air resistance, which in turn affects the improvement of effective thermal efficiency and soot emissions.

[0046] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A high-pressure common rail injection system suitable for nanobubble fuel, the system comprising a fuel tank and a common rail connected via a high-pressure pump, wherein the fuel supply outlet of the common rail is connected to a plurality of three-way solenoid valves, the three-way solenoid valves being further connected to a sprayer, and the common rail and the three-way solenoid valves respectively having a first circuit and a second circuit connected to the fuel tank, characterized in that, A dissolver and a cyclone degasser are also connected in sequence to the first circuit; The dissolver is used to introduce gas and mix it with fuel oil to form a gas-liquid mixture, and the cyclone degasser is used to remove large air bubbles entrained in the gas-liquid mixture.

2. The high-pressure common rail injection system according to claim 1, characterized in that, The cyclone degasser is integrated into the fuel tank.

3. The high-pressure common rail injection system according to claim 1, characterized in that, The solvent has a gas inlet or a circulating fuel inlet at the top and a nanobubble fuel outlet at the bottom. The circulating fuel inlet or gas inlet is located on the side wall of the top. The circulating fuel inlet is connected to the first circuit. A hollow tank is connected below the gas inlet or circulating fuel inlet at the top. The hollow tank is filled with an oleophilic permeable membrane. The side wall of the hollow tank is connected to the circulating fuel inlet or gas inlet. Several small holes are distributed on the bottom wall.

4. The high-pressure common rail injection system according to claim 3, characterized in that, The oleophilic permeable membrane is formed by combining several cylindrical hollow fiber membranes, and the oleophilic permeable membrane occupies 40-60% of the volume of the hollow tank.

5. The high-pressure common rail injection system according to claim 3, characterized in that, The nanobubble fuel outlet is connected to a check ball via a spring, and a container is connected below the nanobubble fuel outlet. The container is fitted over the check ball, and the bottom of the container is open or has an outlet on its bottom wall.

6. The high-pressure common rail injection system according to claim 1, characterized in that, The upper end of the side wall of the cyclone degasser is provided with a tangential liquid inlet, and the top and bottom of the shell are respectively provided with an exhaust port and a liquid outlet; the exhaust port is connected to an exhaust pipe for guiding the separated gas to the outside of the fuel tank.

7. The high-pressure common rail injection system according to claim 1, characterized in that, The height-to-diameter ratio of the cyclone degasser is 3 to 5.

8. A method for high-pressure common rail injection of nanobubble fuel, employing the system described in any one of claims 1-7, characterized in that, Includes the following steps: Nanobubble fuel is pressurized from the fuel tank by a high-pressure pump and delivered to the common rail. A portion of the nanobubble fuel flows out through the first circuit and enters the solvent, forming a circulation loop of solvent-pressure relief valve-cyclone degasser-nanobubble fuel tank-high-pressure pump; another portion of the nanobubble fuel flows from the fuel supply outlet to the three-way solenoid valve.

9. The high-pressure common rail injection method according to claim 8, characterized in that, The three-way solenoid valve adjusts the return oil volume according to the common rail pressure signal to stabilize the common rail pressure.

10. The high-pressure common rail injection method according to claim 9, characterized in that, When the common rail pressure increases, the three-way solenoid valve opens the second circuit, allowing some fuel to return to the fuel tank through the second circuit, thereby reducing the amount of fuel in the common rail and lowering the pressure; when the common rail pressure decreases, the three-way solenoid valve closes the second circuit, while the high-pressure pump continues to supply fuel to the common rail, causing the pressure to rise again.

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