Internal mixing type methanol-hydrogen dual-fuel coaxial ejector and control method

Abstract

The invention discloses an internal mixing type methanol-hydrogen dual-fuel coaxial injector and a control method. The internal mixing type methanol-hydrogen dual-fuel coaxial injector comprises a methanol cracking hydrogen production system and a dual-fuel coaxial injection system, the methanol cracking hydrogen production system comprises a hydrogen branch and a methanol branch; methanol is released through a hydrogen branch, high-purity hydrogen is obtained through a heat exchanger, a reactor and a gas-liquid separator, the separated hydrogen is pressurized through a compressor and then divided into two branches behind the compressor to be connected with a gas channel, the two branches are each provided with a flow controller and a one-way valve, and the gas channel penetrates into the dual-fuel coaxial injection system. Methanol is released through the methanol branch and then enters the dual-fuel coaxial injection system after being pressurized by the pressurizing pump. Methanol-hydrogen mixed injection is achieved in the dual-fuel coaxial injection system, and meanwhile injection of single methanol fuel and single hydrogen fuel can be achieved. The problem that atomization of methyl alcohol is not ideal in the low-pressure jet flow state can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the field of power and energy engineering, and in particular relates to an internal mixing type methanol-hydrogen dual-fuel coaxial injector and a control method thereof. Background Art

[0002] As the most common power device, the internal combustion engine has the advantages of high torque, high thermal efficiency, good durability and economy. It has been used in transportation, aerospace and other fields.

[0003] As the global warming problem becomes increasingly serious, greenhouse gases such as carbon dioxide emitted by the combustion of traditional fossil fuels are the main cause of climate change. In order to cope with the "dual carbon" problem, increasingly stringent emission regulations have prompted future internal combustion engines to use low / zero carbon fuels. Whether in the production link or in the use process, it has significant advantages over traditional fossil fuels, can greatly reduce greenhouse gas emissions, and can even achieve zero greenhouse gas emissions. Methanol, as a green and clean fuel, can be produced from a variety of renewable resources, which helps to achieve sustainable development of energy. However, methanol has poor volatility. In a low temperature environment, methanol fuel is not easy to volatilize to form a combustible mixture, making it difficult to start the engine. In addition, methanol will produce a small amount of acidic substances such as formic acid during the combustion process, which has a corrosive effect on the metal parts of the engine, such as copper, aluminum, and zinc. The ignition energy of hydrogen is very low and the combustion speed is fast. Mixing hydrogen with methanol can complement methanol-hydrogen fuel and achieve clean and efficient combustion. Moreover, the addition of hydrogen helps to improve the combustion process, so that methanol burns more fully, thereby reducing the degree of corrosion to the metal parts of the engine and extending the service life of the engine.

[0004] Methanol-hydrogen is currently the main low / zero carbon fuel to reduce the pressure of pollutant emissions, and is used in ship internal combustion engines through dual-fuel injectors. At present, the structure of dual-fuel injectors is generally coaxial injection and multi-axial injection, and the multi-axial injection device has a complex structure and is relatively less studied. For coaxial injection devices, they are generally divided into internal mixing and external mixing. The external mixing type is that the injector first injects two fuels into the cylinder and mixes them in the cylinder, while the internal mixing type generally achieves fuel mixing inside the injector and then injects it into the cylinder. At present, there are more applications for external mixing. The traditional fuel injection method of the injector is mainly cross-flow injection. The so-called cross-flow injection is an atomization method that injects liquid fuel into the gas cross-flow in a columnar form. The internal mixing dual-fluid injector can convert the liquid column into a liquid film through the atomizing gas. When encountering a cross-flow, the liquid film can promote atomization. Since hydrogen has high storage and transportation costs and technical barriers, and methanol has a relatively high hydrogen content, if hydrogen can be produced online from methanol and the methanol-hydrogen dual fuel is applied to ship internal combustion engines through an internal mixing injector, the problem of hydrogen storage and transportation can be solved, and the cost and risk in the storage and transportation process can be reduced. At present, there is very little research on internal mixing dual fuel injectors, and similar injector products and control strategies are almost blank. Therefore, there is an urgent need for an internal mixing methanol-hydrogen dual fuel coaxial injector and its control method. Summary of the invention

[0005] The object of the present invention is to provide an internal mixing type methanol-hydrogen dual fuel coaxial injector and a control method thereof.

[0006] The purpose of the present invention is achieved through the following technical solutions:

[0007] An internally mixed methanol-hydrogen dual-fuel coaxial injector comprises a methanol cracking hydrogen production system and a dual-fuel coaxial injection system; the methanol cracking hydrogen production system comprises a hydrogen branch and a methanol branch; the hydrogen branch is connected to a No. 1 outlet of a methanol storage tank, a No. 1 gate valve, a heat exchanger, a reactor, a gas-liquid separator, a compressor, a flow controller, a check valve, and a dual-fuel coaxial injection system in sequence through a pipeline; the methanol branch is connected to a No. 2 outlet of a methanol storage tank, a No. 2 gate valve, a pressure pump, a check valve, and a dual-fuel coaxial injection system in sequence through a pipeline; the hydrogen branch releases methanol through the No. 1 outlet of the methanol storage tank, and then obtains high-purity hydrogen through the heat exchanger, the reactor and the gas-liquid separator, and the separated hydrogen is pressurized by a compressor and then divided into two paths after the compressor and connected to gas channels respectively, and both paths are provided with a flow controller and a check valve, and the gas channel runs through the dual-fuel coaxial injection system; the methanol branch releases methanol through the No. 2 outlet of the methanol storage tank and enters the dual-fuel coaxial injection system after being pressurized by a pressure pump.

[0008] Furthermore, the dual-fuel coaxial injection system is arranged in an injector on a cylinder head, comprising a shell, in which a pressure regulating screw, a spring seat, a pressure regulating spring, a gasket, a needle valve, a valve sleeve, a fuel chamber and a premixing chamber are sequentially installed from top to bottom; the pressure regulating screw is externally connected to an ECU control system, and the ECU control system controls the pressure regulating screw to drive the spring seat and the pressure regulating spring at the lower end to move upward, and at the same time drives the needle valve connected to the pressure regulating spring to move upward; the methanol first enters the fuel chamber through a methanol branch, and when the needle valve is lifted, the methanol flows from the fuel chamber into a gap between the valve sleeve and the needle valve, and when the needle valve is lifted, the outer wall surface of the needle valve is separated from the inner wall surface of the shell, and the methanol then flows into the premixing chamber through the gap after the outer wall surface of the needle valve is separated from the inner wall surface of the shell, and then flows into the fuel channel arranged below the premixing chamber.

[0009] Furthermore, the methanol branch is provided with a check valve on the pipeline between the booster pump and the dual-fuel coaxial injection system to prevent methanol backflow.

[0010] Furthermore, the one-way valve of the hydrogen branch prevents gas from flowing back.

[0011] Furthermore, the gate valve is a gate plate of an opening and closing member, which can only be fully opened or fully closed, and cannot adjust the flow rate.

[0012] Furthermore, the fuel cavity is connected to a premixing cavity below; the gas channel runs through the fuel channel, and the gas and fuel are mixed at the gas-liquid intersection where the channels intersect.

[0013] Furthermore, the fuel channel and the spray hole are on the same axis and have the same diameter, which is 2-5 mm and can be adjusted according to actual conditions.

[0014] Furthermore, a gasket is provided between the housing and the top end of the needle valve to reduce the impact and wear between the needle valve and the housing when the needle valve moves back and forth.

[0015] A control method for an internally mixed methanol-hydrogen dual-fuel coaxial injector is provided, wherein the internally mixed methanol-hydrogen dual-fuel coaxial injector comprises three methods: methanol-hydrogen coaxial mixed injection, single methanol fuel injection and single hydrogen fuel injection, as follows:

[0016] Methanol-hydrogen coaxial mixed injection: the hydrogen passes through the gas channel and the fuel channel through which methanol passes, and the hydrogen and methanol are mixed at the gas-liquid intersection to achieve methanol-hydrogen mixed injection; first open the No. 1 gate valve to ensure that hydrogen enters the gas channel first through the hydrogen branch; then open the No. 2 gate valve, and methanol enters the fuel chamber through the methanol branch; when the needle valve is lifted, methanol flows into the premixing chamber, and then flows into the fuel channel arranged below the premixing chamber; hydrogen and methanol are mixed at the gas-liquid intersection and then the fuel is injected through the arranged spray hole;

[0017] Single methanol fuel injection: Close the No. 1 gate valve and open the No. 2 gate valve. The methanol fuel enters the fuel chamber after being adjusted to the required pressure through the methanol branch. When the needle valve is lifted, the methanol flows into the premixing chamber and then flows into the fuel channel arranged below the premixing chamber. The single injection of methanol fuel is completed through the arranged spray hole.

[0018] Single hydrogen fuel injection: Open gate valve No. 1 and close gate valve No. 2. Methanol is used to generate hydrogen through the methanol cracking process. The generated hydrogen is adjusted to the required pressure through the hydrogen branch and then enters the gas channel. The single injection of hydrogen fuel is completed through the set nozzle.

[0019] The beneficial effects of the present invention are:

[0020] The dual-fuel coaxial injector of the present invention provides methanol and hydrogen from a single methanol fuel, thereby realizing methanol-hydrogen mixed injection and injection of a single methanol fuel and hydrogen fuel. At the same time, the internal mixing dual-fuel coaxial injector of the present invention can be operated under low pressure (0.1Mpa-5Mpa). This is because during dual fluid injection, the liquid column injected into the fuel channel moves violently in the mixing port, forming a liquid film flow at the outlet of the mixing port; after injection, the turbulent liquid film also breaks violently and transforms into a well-atomized jet, so that it can effectively make up for the problem of unsatisfactory atomization under low pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a schematic structural diagram of the dual-fuel coaxial injection system described in the present invention.

[0022] Figure 2 This is a schematic diagram of the gas channel penetrating the fuel channel according to the present invention. DETAILED DESCRIPTION

[0023] The present invention is further described below in conjunction with the accompanying drawings.

[0024] like Figure 1 As shown, a dual-fuel coaxial injector includes a methanol cracking hydrogen production system and a dual-fuel coaxial injection system. The methanol cracking hydrogen production system includes a hydrogen branch 6 and a methanol branch 25; the hydrogen branch 6 is connected to the No. 1 outlet of the methanol storage tank 1, the No. 1 gate valve 2, the heat exchanger 3, the reactor 4, the gas-liquid separator 5, the compressor 7, the flow controller 8, the one-way valve 9, and the dual-fuel coaxial injection system in sequence through a pipeline; the methanol branch 25 is connected to the No. 2 outlet of the methanol storage tank 1, the No. 2 gate valve 26, the booster pump 24, the check valve 23, and the dual-fuel coaxial injection system in sequence through a pipeline; the coaxial injection system is arranged in the injector on the cylinder head.

[0025] The methanol storage tank 1 has two outlets, the first outlet is connected to the first gate valve 2 for controlling the on-off of the hydrogen branch 6, and the second outlet is connected to the second gate valve 26 for controlling the on-off of the methanol branch 25. When the engine is started, the second outlet of the methanol storage tank 1 releases the corresponding methanol, which reaches the corresponding pressure (0.1Mpa-5Mpa) through the booster pump 24 and then enters the fuel chamber 15 of the dual-fuel coaxial injection system through the methanol branch 25. The No. 1 outlet of the methanol storage tank 1 releases methanol by opening the No. 1 gate valve 2. The methanol passes through the hydrogen branch 6 through the heat exchanger 3, the reactor 4, and the gas-liquid separator 5 to obtain high-purity hydrogen. The separated hydrogen is pressurized to the corresponding pressure (0.1Mpa-5Mpa) by the compressor 7, and then enters the gas channel 12 in the coaxial injection system through the flow controller 8; the hydrogen branch 6 is divided into two paths after the hydrogen is pressurized and leaves the compressor, and is connected to the gas channel 12 respectively, and the two branches are provided with a flow controller 8 and a one-way valve 9; the one-way valve 9 is used to prevent gas backflow. The gas channel 12 passes through the shell 19 and is connected to the fuel channel 13. A check valve 23 is provided on the methanol branch to prevent methanol backflow.

[0026] The dual-fuel coaxial injection system comprises a housing 19, in which a pressure regulating screw 20, a spring seat 21, a pressure regulating spring 18, a gasket 22, a needle valve 17, a valve sleeve 16, a fuel chamber 15 and a premixing chamber 14 are sequentially installed from top to bottom.

[0027] The pressure regulating screw 20 is connected to the ECU control system. When the engine is started, the ECU controls the spring seat 20 connected to the pressure regulating screw 20, including the pressure regulating spring 18 at the lower end of the spring seat 20, to move upward at the same time, driving the needle valve 17 connected to the pressure regulating spring 18 to move upward. The valve sleeve 16 is wrapped around the outside of the needle valve 17, and a gap is left between the valve sleeve 16 and the needle valve 17. When the needle valve 17 is lifted, methanol flows into the gap between the valve sleeve 16 and the needle valve 17. When the needle valve 17 is lifted, the outer wall surface of the needle valve is separated from the inner wall surface of the shell 19, and then the methanol flows into the premixing chamber 14 through the gap after the outer wall surface of the needle valve 17 is separated from the inner wall surface of the shell 19, and then flows into the fuel channel 13 arranged at the lower side of the premixing chamber 14.

[0028] like Figure 2 As shown, the present invention realizes methanol-hydrogen mixed injection by penetrating the shell 19 through the gas channel 12 to connect the fuel channel 13. The hydrogen and methanol are mixed at the gas-liquid intersection 11 of the gas channel 12 and the fuel channel 13. The present invention takes the case where the gas channel 12 penetrates and connects four fuel channels 15 as an example.

[0029] Methanol-hydrogen dual fuel mixed injection mode: First open the No. 1 gate valve 2 to ensure that hydrogen enters the gas channel 12 first; then open the No. 2 gate valve 26, methanol enters the fuel chamber 15 through the methanol branch 25, and when the needle valve 17 is lifted, the methanol flows into the gap between the needle valve 17 and the valve sleeve 16, and then flows into the premixing chamber 14 through the gap after the outer wall of the needle valve 17 is separated from the inner wall of the shell 19, and then flows into the fuel channel 13 arranged below the premixing chamber 14. Hydrogen and methanol are mixed at the intersection 11 of the gas channel 12 and the fuel channel 13, and then the fuel is sprayed through the spray hole 10.

[0030] Single methanol fuel injection mode: Open the No. 2 gate valve 26 and close the No. 1 gate valve 2, the methanol storage tank 1 releases the corresponding methanol, and the released methanol passes through the booster pump 24 and enters the fuel chamber 15 of the dual-fuel coaxial injection system through the methanol branch 25. The ECU drives the needle valve 17 to move upward by controlling the pressure regulating screw 20 to complete the injection of methanol fuel.

[0031] Single hydrogen fuel injection mode: open gate valve No. 1 2 and close gate valve No. 2 26. Methanol passes through heat exchanger 3, reactor 4, and gas-liquid separator 5 to obtain high-purity hydrogen. The obtained high-purity hydrogen reaches the required pressure through compressor 7, enters gas channel 12 through flow controller 8, and completes the injection of hydrogen fuel through the set nozzle 10.

[0032] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. An internal mixing methanol-hydrogen dual fuel coaxial injector, characterized in that: A methanol cracking hydrogen production system and a dual-fuel coaxial injection system; the methanol cracking hydrogen production system comprises a hydrogen branch (6) and a methanol branch (25); the hydrogen branch (6) is connected in sequence to a No. 1 outlet of a methanol storage tank (1), a No. 1 gate valve (2), a heat exchanger (3), a reactor (4), a gas-liquid separator (5), a compressor (7), a flow controller (8), a check valve (9), and a dual-fuel coaxial injection system through a pipeline; the methanol branch (25) is connected in sequence to a No. 2 outlet of a methanol storage tank (1), a No. 2 gate valve (26), a pressure pump (24), a check valve (23), and a dual-fuel coaxial injection system through a pipeline The hydrogen branch (6) releases methanol through the No. 1 outlet of the methanol storage tank (1), and then obtains high-purity hydrogen through the heat exchanger (3), the reactor (4) and the gas-liquid separator (5). The separated hydrogen is pressurized by the compressor (7), and then divided into two paths after the compressor (7) and connected to the gas channel (12) respectively, and the two branches are provided with a flow controller (8) and a one-way valve (9). The gas channel (12) runs through the dual-fuel coaxial injection system; the methanol branch (25) releases methanol through the No. 2 outlet of the methanol storage tank (1), and enters the dual-fuel coaxial injection system after being pressurized by the booster pump (24).

2. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 1, characterized in that: The dual-fuel coaxial injection system is arranged in an injector on a cylinder head, and comprises a housing (19), wherein a pressure regulating screw (20), a spring seat (21), a pressure regulating spring (18), a gasket (22), a needle valve (17), a valve sleeve (16), a fuel chamber (15) and a premixing chamber (14) are sequentially installed in the housing (19) from top to bottom; the pressure regulating screw (20) is externally connected to an ECU control system, and the ECU control system controls the pressure regulating screw (20), drives the spring seat (21) and the pressure regulating spring (18) at the lower end to move upward, and at the same time drives the needle valve (17) connected to the pressure regulating spring (18) to move upward. 7) moves upward; the valve sleeve (16) is wrapped around the outside of the needle valve (17); the methanol first enters the fuel chamber (15) through the methanol branch (25); when the needle valve (17) is lifted, the methanol flows from the fuel chamber (15) into the gap between the valve sleeve (16) and the needle valve (17); when the needle valve (17) is lifted, the outer wall surface of the needle valve (17) is separated from the inner wall surface of the shell (19); the methanol then flows into the premixing chamber (14) through the gap formed by the separation of the outer wall surface of the needle valve (17) and the inner wall surface of the shell (19), and then flows into the fuel channel (13) arranged below the premixing chamber (14).

3. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 1, characterized in that: The methanol branch (25) is provided with a check valve (23) on the pipeline between the booster pump (24) and the dual-fuel coaxial injection system to prevent methanol from flowing back.

4. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 1, characterized in that: The one-way valve (9) of the hydrogen branch (6) prevents gas from flowing back.

5. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 1, characterized in that: The gate valve is a gate of an opening and closing part, which can only be fully opened or fully closed, and cannot be used to adjust the flow rate.

6. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 2, characterized in that: The fuel cavity (15) is connected to the premixing cavity (14) below; the gas channel (12) penetrates and connects to the fuel channel (13), and the gas and fuel are mixed at the gas-liquid intersection (11) where the channels intersect.

7. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 2, characterized in that: The fuel channel (13) and the spray hole are on the same axis and have the same diameter, which is 2-5 mm.

8. The internal mixing methanol-hydrogen dual fuel coaxial injector according to claim 2, characterized in that: A gasket (22) is provided between the housing (19) and the top end of the needle valve (17).

9. A control method for an internal mixing methanol-hydrogen dual fuel coaxial injector, characterized in that: The internal mixing methanol-hydrogen dual fuel coaxial injector according to any one of claims 1 to 8 includes three methods: methanol-hydrogen coaxial mixed injection, single methanol fuel injection and single hydrogen fuel injection, as follows: Methanol-hydrogen coaxial mixed injection: the hydrogen passes through the gas channel (12) and the fuel channel (13) through which methanol passes, and the hydrogen and methanol are mixed at the gas-liquid intersection (11), thereby realizing the mixed injection of methanol-hydrogen; firstly, the No. 1 gate valve (2) is opened to ensure that the hydrogen enters the gas channel (12) through the hydrogen branch (6) first; then the No. 2 gate valve (26) is opened, and the methanol enters the fuel chamber (15) through the methanol branch (25); when the needle valve (17) is lifted, the methanol flows into the premixing chamber (14), and then flows into the fuel channel (13) arranged below the premixing chamber (14); after the hydrogen and methanol are mixed at the gas-liquid intersection (11), the fuel is injected through the arranged injection hole; Single methanol fuel injection: the No. 1 gate valve (2) is closed and the No. 2 gate valve (26) is opened. The methanol fuel is adjusted to the required pressure through the methanol branch (25) and then enters the fuel chamber (15). When the needle valve (17) is lifted, the methanol flows into the premixing chamber (14) and then flows into the fuel channel (13) arranged below the premixing chamber (14). The single injection of the methanol fuel is completed through the arranged injection hole. Single hydrogen fuel injection: Open the No. 1 gate valve (2) and close the No. 2 gate valve (26), methanol is used to generate hydrogen through a methanol cracking process, the generated hydrogen is adjusted to a required pressure through a hydrogen branch (6) and then enters the gas channel, and a single injection of hydrogen fuel is completed through the set nozzle hole.

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