In-cylinder injection arrangement method and structure of marine dual-fuel engine

Abstract

The invention provides an in-cylinder injection arrangement method and structure for a marine dual-fuel engine, and the method comprises the steps: arranging a low-carbon fuel injector at the center position of the top of a cylinder cover, and injecting low-carbon fuel into the cylinder located at the bottom of the cylinder cover; a plurality of corresponding ignition fuel injectors are arranged according to the cylinder diameter of the air cylinder; the plurality of pilot fuel injectors are arranged on the side edge of the cylinder cover or the side edge of a cylinder sleeve corresponding to the cylinder in a central symmetry manner, and are used for injecting pilot fuel into the cylinder from the side surface; the ignition fuel is low-carbon and zero-carbon fuel; and the injection direction of the pilot fuel injector is adjusted until pilot fuel injection flow injected by the pilot fuel injector covers a low-carbon fuel injection area injected by the low-carbon fuel injector so as to ignite the low-carbon fuel in the air cylinder. According to the dual-fuel injector, the in-cylinder space layout of the dual-fuel injector can be optimized, and carbon emission is reduced.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of ship energy technology, in particular to a cylinder injection arrangement method and structure of a marine dual-fuel engine. BACKGROUND

[0002] The global shipbuilding and shipping industry is accelerating into a low-carbon or even zero-carbon era, and developing green fuel engines is an effective means for the shipbuilding industry to achieve low-carbon / zero-carbon.

[0003] The dual-fuel engine currently uses in-cylinder direct injection, and the injection method is to arrange two direct injection injectors near the center of the cylinder head top, use diesel to ignite low-carbon fuel, that is, inject pilot diesel before the top dead center of compression, and then inject low-carbon fuel into the range of the diesel fire core to ignite, and finally realize the diffusion combustion mode of low-carbon fuel injection process and combustion process at the same time. This injection method requires the diesel jet to cover the low-carbon fuel, and the space on the center of the top of the four-stroke engine cylinder head is compact, which has valves, cooling water channels and other parts, and the space available for arranging two groups of direct injection fuel injectors is very limited, and considering that diesel ignition will inevitably produce CO2, it cannot meet the demand for low-carbon / zero-carbon.

[0004] Therefore, it is necessary to provide a cylinder injection arrangement method and structure of a marine dual-fuel engine to solve the above problems in the prior art. SUMMARY

[0005] In view of the above-mentioned shortcomings of the prior art, the purpose of the present application is to provide a cylinder injection arrangement method and structure of a marine dual-fuel engine to solve the technical problems of limited space on the center of the top of the engine cylinder head and the generation of CO2 by using diesel ignition.

[0006] To solve the above technical problems, the first aspect of the present application provides a cylinder injection arrangement method of a marine dual-fuel engine, comprising:

[0007] arranging a low-carbon fuel injector at the center of the top of the cylinder head for injecting low-carbon fuel into the cylinder located at the bottom of the cylinder head;

[0008] According to the size of the cylinder diameter, a plurality of pilot fuel injectors are arranged in a center-symmetric manner on the side of the cylinder head or on the side of the cylinder liner corresponding to the cylinder for injecting pilot fuel into the cylinder from the side; the pilot fuel is low-carbon or zero-carbon fuel;

[0009] The injection direction of the pilot fuel injector is adjusted until the pilot fuel injection flow injected by the pilot fuel injector covers the low-carbon fuel injection area injected by the low-carbon fuel injector, so as to pilot the low-carbon fuel in the cylinder.

[0010] Furthermore, the process of disposing a plurality of pilot fuel injectors corresponding to the cylinder bore size includes: disposing two pilot fuel injectors if the cylinder bore size range is less than 320 mm; disposing three pilot fuel injectors if the cylinder bore size range is greater than or equal to 320 mm. This advantageously provides the following benefits: by disposing different numbers of pilot fuel injectors for engines with different cylinder bore sizes, the pilot fuel is evenly distributed and effectively covers the injection area of ​​the low-carbon fuel, achieving optimal combustion efficiency.

[0011] Furthermore, if the pilot fuel is a high-cetane fuel, the high-cetane fuel is compression-ignited to ignite the low-carbon fuel. If the pilot fuel is a low-ignition-energy fuel, the ignition source is positioned relative to the corresponding pilot fuel injector so that the ignition source ignites the injected low-ignition-energy fuel. This advantageously allows for the ignition source to be specifically designed for practical use, based on the specific characteristics of the pilot fuel used.

[0012] Furthermore, the ignition source is a spark plug or a plasma igniter.

[0013] Furthermore, the ignition fuel includes one or more of dimethyl ether, polyoxymethylene dimethyl ether, and hydrogen.

[0014] Furthermore, the low-carbon fuel includes one or more of methanol, ammonia, dimethyl ether, and ethanol.

[0015] Furthermore, based on the requirements of the combustion process, at the end of the compression stroke, the plurality of pilot fuel injectors are first controlled to inject pilot fuel, and then the low-carbon fuel injector is controlled to inject low-carbon fuel, so as to optimize the mixing of the pilot fuel and the low-carbon fuel in the cylinder.

[0016] Furthermore, the plurality of pilot fuel injectors inject the pilot fuel according to a preset sequence or simultaneously.

[0017] In order to solve the above technical problems, the second aspect of the present invention provides an in-cylinder injection arrangement structure of a marine dual-fuel engine, comprising:

[0018] cylinder head;

[0019] a low-carbon fuel injector disposed at a top center position of the cylinder head;

[0020] A plurality of pilot fuel injectors are centrally symmetrically arranged on a side of the cylinder head or on a side of the cylinder liner.

[0021] Furthermore, it also includes an ignition source, which is arranged at a relative position to the corresponding pilot fuel injector.

[0022] As described above, the in-cylinder injection arrangement method and structure of the marine dual-fuel engine of the present invention have the following beneficial effects:

[0023] By arranging a low-carbon fuel injector at the top center position of the cylinder head, the low-carbon fuel injector injects low-carbon fuel into the cylinder located below the cylinder head; and, according to the cylinder diameter size, a corresponding plurality of pilot fuel injectors are set, and the plurality of pilot fuel injectors are arranged symmetrically on the side of the cylinder head or on the side of the cylinder liner corresponding to the cylinder, so that the plurality of pilot fuel injectors inject pilot fuel from the side into the cylinder, and the pilot fuel is low-carbon or zero-carbon fuel. Furthermore, the injection direction of the pilot fuel injector is adjusted until the pilot fuel injection flow injected by the pilot fuel injector covers the low-carbon fuel injection area injected by the low-carbon fuel injector to ignite the low-carbon fuel in the cylinder. This application uses the method of injecting low-carbon / zero-carbon fuel into the cylinder to reduce carbon emissions. At the same time, by arranging the pilot fuel injector on the side of the cylinder head or the side of the cylinder liner, the in-cylinder space layout of the dual-fuel injector is optimized. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 Schematic diagram of a flow chart of an in-cylinder injection arrangement method for a marine dual-fuel engine according to an embodiment of the present invention;

[0025] Figure 2 A top view of the in-cylinder injection arrangement for a small to medium bore marine dual-fuel engine;

[0026] Figure 3 A side view of the in-cylinder injection arrangement for a small to medium bore marine dual-fuel engine;

[0027] Figure 4 A top view of the in-cylinder injection arrangement for a large-bore marine dual-fuel engine.

[0028] Component number description

[0029] 1. Low-carbon fuel injector; 2. Cylinder head; 3. Pilot fuel injector; 4. Ignition source; 5. Valve; 6. Piston. DETAILED DESCRIPTION

[0030] The following detailed description is presented to enable any person skilled in the art to make and use the application. Various modifications to the embodiments described herein will be readily apparent to those skilled in the art, and the generic principles defined herein can be applied to other embodiments without departing from the scope of the application. Thus, the present application is not intended to be limited to the embodiments described herein but is to be accorded the widest scope consistent with the claims.

[0031] It is to be understood that the structures, proportions, elements, materials and / or appearances presented herein can be only examples and can be adopted as suitable. Conventional techniques, modifications and / or equivalents of the structures, proportions, elements, materials and / or appearances are intended to be included within the scope of the application. The description and drawings are not intended to limit the scope of the application in any manner.

[0032] In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting", "fixing", "holding" and the like should be interpreted in a broad sense, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0033] Furthermore, as used in this document, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises", "comprising", "includes" and / or "including", when used herein, specify the presence of stated features, operations, elements, components, items, and / or groups thereof, but do not preclude the presence or addition of one or more other features, operations, elements, components, items, and / or groups thereof. As used herein, the terms "or" and "and / or" are to be interpreted as inclusive, i.e., as meaning one or any combination of the items. Thus, "A, B or C" or "A, B and / or C" means any of the following: A; B; C; A and B; A and C; B and C; A, B and C. An exception to this definition will occur only when two or more sequentially listed items are and of the same thing or directly parallel each other, in which case, such a definition is used in only the single thing or directly parallel items are intended, not in their combination.

[0034] For the purpose of promoting an understanding of the principles of the application, reference will now be made to the embodiments illustrated in the drawings and specific language will be used to describe the same. It will, nevertheless, be understood that no limitation of the scope of the application is intended by this Figures 1-4 The detailed description set forth below in connection with the appended drawings is intended as a description of the Figure 1A flow chart of a cylinder injection arrangement method of a marine dual-fuel engine in an embodiment of the present application is shown. The cylinder injection arrangement method of the marine dual-fuel engine in the embodiment mainly comprises the following steps:

[0035] Step S11: A low-carbon fuel injector 1 is arranged at the top center of a cylinder head 2 for injecting low-carbon fuel into a cylinder located at the bottom of the cylinder head 2.

[0036] In this step S11, one cylinder head 2 can correspond to multiple cylinders, or one cylinder head 2 can correspond to one cylinder, which is not specifically limited in this embodiment. One low-carbon fuel injector 1 is arranged for one cylinder. By arranging a low-carbon fuel injector 1 at the top center of a cylinder head 2, the low-carbon fuel injector 1 directly injects low-carbon fuel into the cylinder in a central radial manner from top to bottom (up and down as shown). Figure 2

[0037] In some embodiments of the present application, the low-carbon fuel includes one or more of methanol, ammonia, dimethyl ether, and ethanol. It should be understood that methanol fuel is a simple alcohol compound, which has been widely used in many fields as a high-efficiency clean fuel. It has environmental benefits, reduces particulate matter and NOx emissions, is economically feasible, has mature technology, and has low cost and diverse raw materials, which can be made from coal, natural gas, and biomass. Ammonia fuel is a clean energy with great potential, which does not produce carbon dioxide when burned, and theoretically can achieve "zero-carbon" shipping. Dimethyl ether fuel is used for home heating, bathing, etc. in areas without central heating. Its characteristics are short heating time, generally only 8-15 seconds, and adjustable water temperature according to needs, which can quickly provide hot water, has a long service life, low price, and energy saving, environmental protection, high efficiency, safety, etc. Ethanol fuel is a renewable energy power synthetic fuel, which uses renewable energy power to prepare hydrogen by electrolyzing water, and then synthesizes liquid fuel with carbon dioxide.

[0038] Step S12: According to the cylinder diameter size, a plurality of pilot fuel injectors 3 are arranged in a central symmetric manner on the side of the cylinder head 2 or on the side of the cylinder sleeve corresponding to the cylinder for injecting pilot fuel into the cylinder from the side; the pilot fuel is low-carbon or zero-carbon fuel.

[0039] ​In this step S12, the plurality of pilot fuel injectors 3 are arranged in a central symmetric manner on the side of the cylinder head 2 or on the side of the cylinder liner corresponding to the cylinder, so that the plurality of pilot fuel injectors 3 directly inject pilot fuel into the cylinder from the side of the cylinder, not only to increase the arrangement selection range of the pilot fuel injectors 3 and optimize the layout of the cylinder space, but also to effectively save the space on the top of the cylinder head 2, and to inject the pilot fuel into the cylinder from the side, so as to mix the pilot fuel with the low-carbon fuel more uniformly by using the vortex effect in the cylinder, thereby improving the combustion efficiency. Each cylinder is provided with a cylinder liner for reducing the friction between the piston 6 and the cylinder wall and protecting the cylinder wall from wear. That is, one cylinder corresponds to one cylinder liner. It should be noted that in this embodiment, the specific arrangement position of the plurality of pilot fuel injectors 3 can be simulated and optimized based on existing simulation software, so as to ensure that the pilot fuel injected by the pilot fuel injectors 3 into the cylinder follows the vortex direction in the cylinder, and the pilot fuel is mixed with the low-carbon fuel better, thereby improving the combustion efficiency.

[0040] As shown in Figure 2 , Figure 3 and Figure 4 , in some embodiments of the present application, the process of setting a plurality of pilot fuel injectors 3 according to the cylinder diameter size includes: if the cylinder diameter size is less than 320 mm, two pilot fuel injectors 3 are set; and if the cylinder diameter size is greater than or equal to 320 mm, three pilot fuel injectors 3 are set.

[0041] In this embodiment, the cylinder with a cylinder diameter size less than 320 mm is defined as a small or medium cylinder diameter, and for a small or medium cylinder diameter engine, two pilot fuel injectors 3 are arranged in a central symmetric manner on the side of the cylinder head 2 or on the cylinder liner relative to the center position of the cylinder, so that the pilot fuel injectors 3 inject pilot fuel into the cylinder from the side. The cylinder with a cylinder diameter size greater than or equal to 320 mm is defined as a large cylinder diameter, and for a large cylinder diameter engine, three pilot fuel injectors 3 are arranged in a central symmetric manner on the side of the cylinder head 2 or on the cylinder liner relative to the center position of the cylinder, so that the pilot fuel injectors 3 inject pilot fuel into the cylinder from the side. By configuring different numbers of pilot fuel injectors 3 for engines with different cylinder diameters, it is ensured that the pilot fuel can be uniformly distributed and effectively cover the injection area of the low-carbon fuel, thereby achieving the best combustion efficiency.

[0042] As shown in Figure 2 and Figure 4As shown in FIG. 1, in some embodiments of the present application, if the pilot fuel is a high cetane number fuel, the high cetane number fuel is self-ignited by compression ignition to ignite the low carbon fuel; if the pilot fuel is a low ignition energy fuel, the ignition source 4 is arranged at a relative position of the corresponding pilot fuel injector 3 so that the ignition source 4 ignites the injected low ignition energy fuel. In this embodiment, the pilot fuel injected by the pilot fuel injector 3 is a high cetane number fuel, which is ignited by compression ignition based on the lower self-ignition point characteristics of the high cetane number fuel, without an external ignition source 4. The pilot fuel injected by the pilot fuel injector 3 is a low ignition energy fuel, which needs an external ignition source 4 to control the ignition timing and start the combustion reaction of the pilot fuel based on the higher self-ignition point characteristics of the low ignition energy fuel. At this time, the ignition source 4 is arranged at a relative position of the pilot fuel injector 3, i.e. the ignition source 4 is located at the edge of the pilot fuel jet to control the ignition timing. Further, whether to arrange the ignition source 4 depends on the type of pilot fuel used, which can be designed according to actual use.

[0043] As shown in FIG. 1, in some embodiments of the present application, the ignition source 4 is a spark plug or a plasma igniter. It should be understood that the spark plug ignites the pilot fuel by the electric spark generated between the electrodes, which has the advantages of simple structure, low cost, easy maintenance, etc. The ignition energy and ignition position of the spark plug can be accurately controlled according to the needs of the engine. The plasma igniter ignites the pilot fuel by generating high-temperature plasma through high-frequency electric arc, which has the advantages of reliable ignition, high ignition energy, strong adaptability, etc. Figure 2 Figure 4 As shown in FIG. 1, in some embodiments of the present application, the ignition source 4 is a spark plug or a plasma igniter. It should be understood that the spark plug ignites the pilot fuel by the electric spark generated between the electrodes, which has the advantages of simple structure, low cost, easy maintenance, etc. The ignition energy and ignition position of the spark plug can be accurately controlled according to the needs of the engine. The plasma igniter ignites the pilot fuel by generating high-temperature plasma through high-frequency electric arc, which has the advantages of reliable ignition, high ignition energy, strong adaptability, etc.

[0044] As shown in FIG. 1, in some embodiments of the present application, the ignition source 4 is a spark plug or a plasma igniter. It should be understood that the spark plug ignites the pilot fuel by the electric spark generated between the electrodes, which has the advantages of simple structure, low cost, easy maintenance, etc. The ignition energy and ignition position of the spark plug can be accurately controlled according to the needs of the engine. The plasma igniter ignites the pilot fuel by generating high-temperature plasma through high-frequency electric arc, which has the advantages of reliable ignition, high ignition energy, strong adaptability, etc. Figure 2 Figure 4 As shown in FIG. 1, in some embodiments of the present application, the pilot fuel includes one or more of dimethyl ether, polymethyl ether, and hydrogen. It should be understood that dimethyl ether fuel is a high-purity fuel with high cetane number, which can be self-ignited by compression ignition in the compression stroke without the need for an additional ignition source 4. Polymethyl ether fuel is a series of ether compounds with different degrees of polymerization, which has high cetane number and can achieve compression ignition. Hydrogen fuel is a clean fuel with very high combustion speed and low ignition energy, so an ignition source 4 is needed to control the ignition timing for ignition.

[0045] ​​The method for arranging the in-cylinder injection of the marine dual-fuel engine of the present application uses a low-carbon fuel injector 1 to inject low-carbon fuel and a pilot fuel injector 3 to inject low-carbon or zero-carbon fuel as pilot fuel instead of using diesel as pilot fuel, thereby avoiding the generation of CO2 and reducing carbon emissions to meet the green requirements in the field of new energy for ships. Specifically, the low-carbon fuel injector 1 directly injects low-carbon fuel into the cylinder from top to bottom, and the two or three pilot fuel injectors 3 inject low-carbon or zero-carbon fuel as pilot fuel into the cylinder from the side, the pilot fuel is compressed or ignited by the ignition source 4, and the pilot fuel covers the flame front of the low-carbon fuel, when the leading edge of the low-carbon fuel contacts the flame range of the pilot fuel, it can be ignited to form diffusion combustion. At the same time, the injection of the pilot fuel utilizes the vortex effect in the cylinder to better mix with the low-carbon fuel to form a uniform mixture, and the pilot fuel jet can better ignite the centrally injected low-carbon fuel.

[0046] It should be noted that the order between step S11 and step S12 is not specifically limited in this embodiment, that is, the low-carbon fuel injector 1 can be arranged first, or the pilot fuel injector 3 can be arranged first.

[0047] Step S13: Adjust the injection direction of the pilot fuel injector 3 until the pilot fuel injection stream injected by the pilot fuel injector 3 covers the low-carbon fuel injection area injected by the low-carbon fuel injector 1 to ignite the low-carbon fuel in the cylinder.

[0048] In this step S13, the injection direction of the pilot fuel injected by the pilot fuel injector 3 is adjusted so that the flame range of the injected pilot fuel covers the flame surface of the low-carbon fuel as much as possible to ignite the low-carbon fuel in the cylinder, improve the combustion efficiency, and help to enhance the stability of ignition under various working conditions.

[0049] For example, the injection process of the pilot fuel and the low-carbon fuel is simulated and optimized based on a computational fluid dynamics (CFD) platform, the flame coverage of the two fuels is controlled by adjusting the spray-related parameters of the pilot fuel and the low-carbon fuel, and it is ensured that the flame of the pilot fuel covers the low-carbon fuel. It should be understood that the computational fluid dynamics (CFD) platform is a numerical method for simulating fluid flow, heat transfer and related phenomena, which is a widely used technology in engineering and scientific research fields for analyzing and optimizing problems involving fluid dynamics.

[0050] For example, the injection process of the pilot fuel and the low-carbon fuel is simulated and optimized based on a computational fluid dynamics (CFD) platform, the flame coverage of the two fuels is controlled by adjusting the spray-related parameters of the pilot fuel and the low-carbon fuel, and it is ensured that the flame of the pilot fuel covers the low-carbon fuel. It should be understood that the computational fluid dynamics (CFD) platform is a numerical method for simulating fluid flow, heat transfer and related phenomena, which is a widely used technology in engineering and scientific research fields for analyzing and optimizing problems involving fluid dynamics. Figure 2 and Figure 3As shown, in some embodiments of the present application, based on the requirements of the combustion process, the pilot fuel injectors 3 are controlled to inject pilot fuel first, and then the low-carbon fuel injectors 1 are controlled to inject low-carbon fuel at the end of the compression stroke, so as to optimize the mixing of the pilot fuel and the low-carbon fuel in the cylinder. In this embodiment, by controlling the injection timing of the low-carbon fuel injectors 1 and the pilot fuel injectors 3, specifically, during the intake opening of the valve 5, air is inhaled, and during the intake closing of the valve 5, the piston 6 starts to move upward, the temperature rises, and the pressure rises; near the compression top dead center, the pilot fuel injectors 3 are controlled to inject pilot fuel from the side into the cylinder first, and then the low-carbon fuel injectors 1 are controlled to inject low-carbon fuel from top to bottom into the cylinder, the fuel directly enters the high-temperature and high-pressure environment, and after the pilot fuel is ignited by the compression ignition or the ignition source 4, a flame range is formed, when the low-carbon fuel front surface contacts the flame range of the pilot fuel, it is ignited to form diffusion combustion. At the same time, the vortex effect in the cylinder is utilized to make the mixing of the pilot fuel and the low-carbon fuel more uniform, forming a uniform combustible mixture, further combustion work is carried out, and the combustion efficiency is improved.

[0051] In some other embodiments of the present application, the low-carbon fuel injectors 1 inject low-carbon fuel during the intake stroke, so that there is sufficient time for the low-carbon fuel to mix with the intake air to form a uniform mixture; the pilot fuel injectors 3 inject pilot fuel at the end of the compression stroke, at this time, the cylinder is in a high-temperature and high-pressure state, which is beneficial to the self-ignition of the pilot fuel, so as to achieve the best mixing effect of the pilot fuel and the low-carbon fuel, when the low-carbon fuel front surface contacts the flame range of the pilot fuel, it is ignited to form diffusion combustion, and the combustion efficiency is improved.

[0052] It should be noted that the specific injection sequence of the low-carbon fuel injectors 1 and the pilot fuel injectors 3 is not limited, and factors such as the design of the engine, the characteristics of the fuel, the control requirements of the combustion process, and the emission control should be considered comprehensively, so as to achieve the best combustion effect.

[0053] As shown in FIGS. Figure 2 and Figure 4 As shown in some embodiments of the present application, the plurality of pilot fuel injectors 3 inject pilot fuel according to a predetermined sequence or simultaneously. In this embodiment, whether it is 2 beams of pilot fuel for small and medium cylinder diameter engines or 3 beams of pilot fuel for large cylinder diameter engines, independent sequential injection or simultaneous injection can be performed according to the matching of the oil and gas chamber, and this is not limited.

[0054] Further, due to the difference in the properties of the two fuels, in actual operation, it is also necessary to accurately control the injection timing, injection amount and other parameters of the two fuels to ensure the stability of the combustion process. For example, based on the CONVERGE three-dimensional simulation software, combined with fluid mechanics modeling, chemical reaction kinetics and other methods, by adjusting the injection timing, injection amount, the results of fuel consumption, effective pressure, emissions and the like are comprehensively evaluated to achieve a better combustion effect. Specifically, a three-dimensional geometric model of a marine dual-fuel engine is created, which includes a cylinder, a cylinder head 2, a pilot fuel injector 3, a low-carbon fuel injector 1, a valve 5 and a piston 6; the created three-dimensional geometric model is meshed to generate a mesh for numerical calculation; a turbulence model is set to simulate the flow characteristics in the cylinder, and the chemical reaction mechanism of the fuel used is defined; the boundary conditions of the intake port, the exhaust port, the cylinder wall surface and the like are defined, and the state in the cylinder at the beginning of the simulation is defined; the arrangement position of the pilot fuel injector 3 and the low-carbon fuel injector 1, the number of injection holes of each injector and the spray cone angle and other parameters are set, and the injection timing and injection amount of each injector are defined; the entire combustion process is simulated, and key data such as pressure, temperature, velocity and the like during the simulation process are collected; based on the collected simulation data, the injection timing, injection amount and other parameters are adjusted; the iteration optimization is continuously carried out until the best combustion effect is achieved. It should be understood that the CONVERGE three-dimensional simulation software is a comprehensive computational fluid dynamics (CFD) software suite suitable for multiple vertical markets including automobiles, turbomachinery, marine, aerospace and the like, and this software is known for its unique solver-based automatic meshing technology, which means that the user does not need to make special adjustments to the geometry or pre-design the mesh arrangement when modeling, and only needs to simply specify the motion law of the moving boundary.

[0055] As shown in Figure 2-Figure 4 The application also provides an in-cylinder injection arrangement structure of a marine dual-fuel engine, which comprises a cylinder head 2; one low-carbon fuel injector 1 arranged at the top center position of the cylinder head 2; and a plurality of pilot fuel injectors 3 arranged in a central symmetric manner at the side edges of the cylinder head 2 or the side edges of the cylinder liner. It should be noted that one cylinder corresponds to one low-carbon fuel injector 1 and a plurality of pilot fuel injectors 3.

[0056] By arranging a low-carbon fuel injector 1 at the top center of the cylinder head 2, the low-carbon fuel injector 1 is made to inject low-carbon fuel into the cylinder located below the cylinder head 2; and, according to the cylinder diameter size, a corresponding plurality of pilot fuel injectors 3 are set, and the plurality of pilot fuel injectors 3 are arranged symmetrically on the side of the cylinder head 2 or on the side of the cylinder sleeve corresponding to the cylinder, so that the plurality of pilot fuel injectors 3 inject pilot fuel from the side into the cylinder, and the pilot fuel is a low-carbon or zero-carbon fuel. Further, the injection direction of the pilot fuel injector 3 is adjusted until the pilot fuel injector 3 sprays The injected pilot fuel jet covers the low-carbon fuel injection area injected by the low-carbon fuel injector 1 to ignite the low-carbon fuel in the cylinder. The present application optimizes the in-cylinder space layout of the dual-fuel injector by arranging the pilot fuel injector 3 on the side of the cylinder head 2 or the side of the cylinder liner, saving space on the top of the cylinder head 2. At the same time, all low-carbon / zero-carbon fuels are used to be injected into the cylinder to avoid the generation of CO2 and reduce carbon emissions. The pilot fuel is injected into the cylinder from the side of the cylinder, so that the pilot fuel can utilize the vortex effect in the cylinder to mix more evenly with the low-carbon fuel, thereby improving the combustion efficiency of the combustion chamber.

[0057] like Figure 2 and Figure 4 As shown, in some embodiments of the present invention, the in-cylinder injection arrangement structure of the marine dual-fuel engine further includes an ignition source 4, which is disposed at a position corresponding to the pilot fuel injector 3. When the pilot fuel of this embodiment uses a low ignition energy fuel, the ignition source 4 is required to initiate the combustion reaction of the pilot fuel to ignite the low-carbon fuel.

[0058] In summary, in view of the problems of limited space in the center of the top of the engine cylinder head and CO2 generated by using diesel pilot in the prior art, the application provides a cylinder injection arrangement method and structure of a marine dual-fuel engine, a low-carbon fuel injector 1 is arranged at the top center of the cylinder head 2, so that the low-carbon fuel injector 1 sprays low-carbon fuel in a central radial manner from top to bottom into the cylinder; and according to the cylinder diameter, a plurality of pilot fuel injectors 3 are arranged, specifically, for small and medium cylinder diameter engines, two pilot fuel injectors 3 are arranged; for large cylinder diameter engines, three pilot fuel injectors 3 are arranged; and the two or three pilot fuel injectors 3 are arranged symmetrically at the side of the cylinder head 2 or at the side of the cylinder liner corresponding to the cylinder, so that the two or three pilot fuel injectors 3 spray pilot fuel from the side into the cylinder, the pilot fuel is low-carbon or zero-carbon fuel, further, the injection direction of the pilot fuel injector 3 is adjusted until the pilot fuel injection flow of the pilot fuel injector 3 covers the low-carbon fuel injection area of the low-carbon fuel injector 1 to pilot the low-carbon fuel in the cylinder, by arranging two or three pilot fuel injectors 3 at the side of the cylinder head 2 or the side of the cylinder liner, the in-cylinder space layout of the dual-fuel injector is optimized, and the space at the top of the cylinder head 2 is saved; at the same time, the use of low-carbon / zero-carbon fuel to spray into the cylinder avoids the generation of CO2, reduces carbon emissions, and the pilot fuel is sprayed into the cylinder from the side of the cylinder, so that the pilot fuel can be mixed with the low-carbon fuel more uniformly by using the vortex effect in the cylinder, and the combustion efficiency of the combustion chamber is improved. Therefore, the application effectively overcomes the shortcomings of the prior art and has high industrial utilization value.

[0059] The above embodiments only exemplarily illustrate the principles and effects of the application, and are not used to limit the application. Any person skilled in the art can modify or change the above embodiments without departing from the spirit and scope of the application. Therefore, all equivalent modifications or changes made by those skilled in the art without departing from the spirit and technical thought disclosed by the application should be covered by the claims of the application.

Claims

1. A method for arranging in-cylinder injection of a marine dual-fuel engine, characterized in that: include: A low-carbon fuel injector is arranged at the top center of the cylinder head to inject low-carbon fuel into the cylinder located at the bottom of the cylinder head; A plurality of pilot fuel injectors are provided according to the cylinder diameter; the pilot fuel injectors are centrally and symmetrically arranged on the side of the cylinder head or on the side of the cylinder liner corresponding to the cylinder, for injecting the pilot fuel into the cylinder from the side; the pilot fuel is a low-carbon or zero-carbon fuel; The injection direction of the pilot fuel injector is adjusted until the pilot fuel injection flow injected by the pilot fuel injector covers the low-carbon fuel injection area injected by the low-carbon fuel injector, so as to pilot the low-carbon fuel in the cylinder.

2. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 1, characterized in that: The process of setting a plurality of corresponding pilot fuel injectors according to the cylinder diameter includes: If the cylinder diameter is less than 320 mm, two pilot fuel injectors are provided; If the cylinder diameter range is greater than or equal to 320 mm, three pilot fuel injectors are provided.

3. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 1, characterized in that: If the pilot fuel is a high cetane number fuel, the high cetane number fuel is compression ignited to ignite the low-carbon fuel; if the pilot fuel is a low ignition energy fuel, the ignition source is arranged at a relative position of the corresponding pilot fuel injector so that the ignition source ignites the injected low ignition energy fuel.

4. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 3, characterized in that: The ignition source is a spark plug or a plasma igniter.

5. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 1, characterized in that: The pilot fuel includes one or more of dimethyl ether, polyoxymethylene dimethyl ether, and hydrogen.

6. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 1, characterized in that: The low-carbon fuel includes one or more of methanol, ammonia, dimethyl ether, and ethanol.

7. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 1, characterized in that: Based on the requirements of the combustion process, at the end of the compression stroke, the plurality of pilot fuel injectors are first controlled to inject pilot fuel, and then the low-carbon fuel injector is controlled to inject low-carbon fuel, so as to optimize the mixing of the pilot fuel and the low-carbon fuel in the cylinder.

8. The method for arranging in-cylinder injection of a marine dual-fuel engine according to claim 7, characterized in that: The plurality of pilot fuel injectors inject the pilot fuel according to a preset sequence or simultaneously.

9. An in-cylinder injection arrangement structure for a marine dual-fuel engine, characterized in that: include: cylinder head; a low-carbon fuel injector disposed at a top center position of the cylinder head; A plurality of pilot fuel injectors are centrally symmetrically arranged on a side of the cylinder head or on a side of the cylinder liner.

10. The in-cylinder injection arrangement structure of a marine dual-fuel engine according to claim 1, characterized in that: Also included is an ignition source, which is disposed at a relative position to the corresponding pilot fuel injector.

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