Marine twin direct injection engine system and control method thereof

Abstract

The application discloses a marine dual direct injection engine system and a control method thereof, and is applied to the technical field of engines, and can realize clean, efficient and controllable combustion of the engine in a wide operating condition range, and effectively alleviates the problem of limited operating conditions. The system comprises a methanol supply module, a diesel oil supply module and an engine. The methanol supply module is used for supplying methanol. The diesel oil supply module is used for supplying diesel oil. The engine comprises an air intake manifold, an exhaust manifold and a fuel input end, and is used for combusting the input diesel oil and methanol. The methanol cracking module comprises a cracking input end and a cracking output end, is used for cracking the input methanol, obtains methanol cracking gas, and inputs the methanol cracking gas into the engine through the air intake manifold. The exhaust gas recirculation module comprises an exhaust gas input end, a first exhaust gas output pipeline and a second exhaust gas output pipeline. The exhaust gas input end is connected with the exhaust manifold. The first exhaust gas output pipeline is connected with the air intake manifold. The second exhaust gas output pipeline is used for discharging the exhaust gas generated by the engine.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a marine dual direct injection engine system and its control method. Background Technology

[0002] Methanol, with its low carbon content, high octane number, high oxygen content, low pollution, and smokeless emissions, has gradually been recognized by the shipping industry as an ideal new type of clean and renewable fuel. Currently, the mainstream application of methanol fuel in marine engines is the DMCC (Diesel-Modulated Combustion-Cylinder Mixture) mode, where methanol is injected through the intake manifold and diesel fuel is directly injected to ignite the methanol-air mixture. However, in the DMCC mode, the methanol substitution rate is severely limited by operating conditions, making it difficult to achieve a high methanol substitution rate across a wide range of operating conditions while ensuring reliable ignition and stable combustion. Furthermore, methanol has a high latent heat of vaporization, a fast flame propagation speed, and complex interactions with diesel fuel. Under low loads, excessive fuel-air mixing is likely, while under high loads, coarse combustion is prone to occur. Achieving clean, efficient, and controllable combustion across the entire operating range is challenging. Therefore, these technical problems urgently need to be addressed. Summary of the Invention

[0003] To address at least one of the aforementioned technical problems, this invention proposes a marine dual direct injection engine system and its control method, which enables clean, efficient, and controllable combustion of the engine within a wide operating range, effectively alleviating the problem of limited operating conditions.

[0004] On one hand, embodiments of the present invention provide a marine dual direct injection engine system, comprising:

[0005] A methanol supply module for injecting methanol into the cylinders of the engine;

[0006] A diesel supply module for injecting diesel fuel into the cylinders of the engine;

[0007] An engine, comprising an intake manifold, an exhaust manifold, and a fuel input terminal, wherein the fuel input terminal is connected to the methanol supply module and the diesel supply module respectively, and the engine is used to burn the input diesel and methanol;

[0008] A methanol cracking module includes a cracking input terminal, a cracking output terminal, a methanol cracking reactor, and a catalyst pipeline. The cracking input terminal is connected to the methanol supply module to input methanol supplied by the methanol supply module into the methanol cracking reactor. The cracking output terminal is connected to the intake manifold. The methanol cracking reactor utilizes the exhaust heat of the engine combined with the cracking catalyst provided by the catalyst pipeline to crack the input methanol, obtaining methanol cracked gas, which is then input into the engine through the intake manifold.

[0009] The exhaust gas recirculation module includes an exhaust gas input terminal, a first exhaust gas output pipeline, and a second exhaust gas output pipeline. The exhaust gas input terminal is connected to the exhaust manifold through the methanol cracking module. The first exhaust gas output pipeline is connected to the intake manifold. The second exhaust gas output pipeline is used to discharge the exhaust gas generated by the engine.

[0010] According to some embodiments of the present invention, the methanol supply module includes:

[0011] A methanol tank for storing and discharging the methanol;

[0012] A preset methanol pump is provided, which includes a methanol pump input terminal and a methanol pump output terminal. The methanol pump input terminal is connected to the methanol tank. The preset methanol pump is used to provide pressure to the methanol tank so as to output the methanol in the methanol tank.

[0013] The first shut-off valve includes a first shut-off input terminal and a first shut-off output terminal. The first shut-off input terminal is connected to the output terminal of the methanol pump. The first shut-off valve is used to control the first working state of the methanol supply module.

[0014] A methanol flow meter, comprising a first flow meter input terminal and a first flow meter output terminal, wherein the first flow meter input terminal is connected to a first cutoff output terminal, and the methanol flow meter is used to measure and regulate the output of methanol.

[0015] A methanol common rail submodule includes a first common rail input terminal and a first common rail output terminal. The first common rail input terminal is connected to the output terminal of the first flow meter. The methanol common rail submodule is used to control and regulate the methanol output state.

[0016] A preset methanol injector includes a methanol injection end and a first injector input end, the first injector input end being connected to a first common rail output end, and the methanol injection end being used to inject methanol into the cylinder of the engine.

[0017] According to some embodiments of the present invention, the diesel supply module includes:

[0018] A diesel tank for storing and discharging diesel fuel;

[0019] A preset diesel pump, comprising a diesel pump input end and a diesel pump output end, wherein the diesel pump input end is connected to the diesel tank, and the preset diesel pump is used to provide pressure to the diesel tank to output diesel fuel from the diesel tank;

[0020] The second shut-off valve includes a second shut-off input terminal and a second shut-off output terminal. The second shut-off input terminal is connected to the output terminal of the diesel pump. The second shut-off valve is used to control the second working state of the diesel supply module.

[0021] A diesel flow meter, comprising a second flow meter input terminal and a second flow meter output terminal, wherein the second flow meter input terminal is connected to a second cut-off output terminal, and the diesel flow meter is used to measure and regulate the output of diesel fuel.

[0022] A diesel common rail submodule includes a second common rail input terminal and a second common rail output terminal. The second common rail input terminal is connected to the output terminal of the second flow meter. The diesel common rail submodule is used to control and regulate the diesel output status.

[0023] A preset diesel injector includes a diesel injection end and a second injector input end, the second injector input end being connected to a second common rail output end, and the diesel injection end being used to inject the diesel fuel into the cylinder of the engine.

[0024] According to some embodiments of the present invention, the system further includes:

[0025] A turbocharger, comprising a first intake end, a first outlet end, a second intake end, and a second outlet end, wherein the second intake end is connected to a second exhaust gas output pipeline, the first intake end is used to input air, and the second outlet end is used to discharge exhaust gas.

[0026] An exhaust gas-air mixer includes a first mixing input terminal, a second mixing input terminal, and a first mixing output terminal. The first mixing input terminal is connected to a first air outlet terminal, and the second mixing input terminal is connected to the first exhaust gas output pipeline through an exhaust gas recirculation valve. The exhaust gas-air mixer is used to mix the air obtained by the turbocharger with the exhaust gas to obtain a first mixed gas.

[0027] A methanol cracking gas mixer includes a third mixing input terminal, a fourth mixing input terminal, and a second mixing output terminal. The third mixing input terminal is connected to the first mixing output terminal, and the fourth mixing input terminal is connected to the cracking output terminal through a cracking gas valve. The methanol cracking gas mixer is used to mix the first mixed gas with the methanol cracking gas to obtain a target mixed gas.

[0028] An intercooler, comprising an intercooler input terminal and an intercooler output terminal, wherein the intercooler input terminal is connected to the second mixing output terminal and the intercooler output terminal is connected to the intake manifold, and the intercooler is used to cool the target gas mixture.

[0029] On the other hand, embodiments of the present invention also provide a control method for a marine dual direct injection engine system, applied to the control system of the aforementioned marine dual direct injection engine system, comprising:

[0030] Obtain preset engine parameters, wherein the preset engine parameters include engine speed, engine desired power, and engine rated power;

[0031] The engine operating mode is determined based on the engine speed, the desired engine power, and the rated engine power.

[0032] The operating state of the preset control module is adjusted according to the engine operating mode; wherein, the preset control module includes a methanol cracking module, an exhaust gas recirculation module, a methanol supply module, and a diesel supply module.

[0033] According to some embodiments of the present invention, determining the engine operating mode based on the engine speed, the desired engine power, and the rated engine power includes:

[0034] When the engine speed is determined to be zero, the engine operating mode is determined to be cold start operating mode;

[0035] Alternatively, when it is determined that the engine speed is not zero and the engine's expected power is less than or equal to a first threshold of the engine's rated power, the engine operating mode is determined to be a low-load operating mode.

[0036] Alternatively, when it is determined that the engine speed is not zero, the engine's expected power is greater than the first threshold, and the engine's expected power is less than or equal to the second threshold of the engine's rated power, the engine operating mode is determined to be a medium load operating mode.

[0037] Alternatively, when it is determined that the engine speed is not zero and the engine's expected power is greater than the second threshold, the engine operating mode is determined to be a high-load operating mode.

[0038] According to some embodiments of the present invention, the step of adjusting the engine operating state by controlling the operating state of the preset control module according to the engine operating condition mode includes:

[0039] When the engine operating mode is determined to be the cold start operating mode, the exhaust gas recirculation module is turned off, and the diesel supply module is controlled to output diesel to the engine.

[0040] The methanol supply module is controlled to output methanol to the methanol cracking module for methanol cracking reaction to obtain methanol cracked gas, and the methanol cracked gas is input into the engine.

[0041] According to some embodiments of the present invention, the step of adjusting the engine operating state by controlling the operating state of the preset control module according to the engine operating condition mode further includes:

[0042] When the engine operating mode is determined to be the low load operating mode, the methanol cracking module, the diesel supply module, and the methanol supply module are controlled to be turned on.

[0043] Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol-mixed restricted combustion mode;

[0044] The first injection parameters, methanol cracking hydrogen production rate, and methanol energy ratio are adjusted according to the first preset output parameters; wherein, the first preset output parameters include engine exhaust temperature and engine load requirements, and the first injection parameters include methanol injection timing and diesel injection timing.

[0045] The intake valve of the engine is opened a second time according to a preset valve control law to perform internal exhaust gas recirculation.

[0046] According to some embodiments of the present invention, the step of adjusting the engine operating state by controlling the operating state of the preset control module according to the engine operating condition mode further includes:

[0047] When the engine operating mode is determined to be the medium load operating mode, the exhaust gas recirculation module, the methanol cracking module, the diesel supply module, and the methanol supply module are controlled to be turned on.

[0048] Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in the methanol homogeneous charge premixed combustion mode;

[0049] The first injection parameters, methanol cracking hydrogen production rate, methanol energy ratio, and exhaust gas recirculation rate are adjusted according to the second preset output parameters; wherein, the second preset output parameters include engine load demand, knock output feedback, and knock pressure output feedback, and the first injection parameters include methanol injection timing and diesel injection timing.

[0050] According to some embodiments of the present invention, the step of adjusting the engine operating state by controlling the operating state of the preset control module according to the engine operating condition mode further includes:

[0051] When the engine operating mode is determined to be the high-load operating mode, the exhaust gas recirculation module, the diesel supply module, and the methanol supply module are activated.

[0052] Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol partially premixed combustion mode;

[0053] The second injection parameters and exhaust gas recirculation rate are adjusted according to the third preset output parameters; wherein, the third preset output parameters include engine load requirements, knock output feedback and knock pressure output feedback, and the second injection parameters include methanol primary injection ratio, methanol secondary injection ratio, methanol injection timing and diesel injection timing.

[0054] According to an embodiment of the present invention, a marine dual direct injection engine system and its control method have at least the following beneficial effects: The embodiments of the present invention control the methanol supply module and the diesel supply module to flexibly control the engine's combustion mode and fuel ratio, thereby adapting to the needs of different navigation conditions. Simultaneously, the embodiments of the present invention use an exhaust gas recirculation module to recirculate external exhaust gas to regulate the combustion rate, reduce the combustion rate, and prevent knocking pressure from exceeding limits and knocking. Furthermore, the embodiments of the present invention use a methanol cracking module to crack the input methanol to achieve methanol cracking and hydrogen-blended combustion, effectively accelerating the combustion rate. It is readily understood that by combining the methanol cracking module and the exhaust gas recirculation module, the embodiments of the present invention can regulate the combustion rate while achieving a high methanol substitution rate, thereby achieving clean, efficient, and controllable combustion of the engine within a wide operating range, effectively alleviating the problem of limited operating conditions. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the marine dual direct injection engine system provided in an embodiment of the present invention;

[0056] Figure 2 This is a flowchart of the control method for a marine dual direct injection engine system provided in an embodiment of the present invention;

[0057] Figure 3This is a schematic diagram of the methanol mixed restricted combustion mode provided in the embodiments of the present invention;

[0058] Figure 4 This is a schematic diagram of the secondary opening of the intake valve provided in an embodiment of the present invention;

[0059] Figure 5 This is a schematic diagram of the methanol homogeneous charge premixed combustion mode provided in the embodiments of the present invention;

[0060] Figure 6 This is a schematic diagram of the methanol partially premixed combustion mode provided in an embodiment of the present invention. Detailed Implementation

[0061] The embodiments described in this application should not be considered as limitations on this application. All other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0062] In the following description, references are made to “some embodiments,” which describe a subset of all possible embodiments. However, it is understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0063] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing embodiments of this application only and is not intended to limit this application.

[0064] Before describing the embodiments of this application, the relevant terms involved in this application will be explained.

[0065] Exhaust Gas Recirculation (EGR) is an engine emission control technology that introduces a portion of exhaust gas back into the engine system, replacing some of the fresh air and thus controlling the combustion rate to improve engine performance. EGR technology includes external and internal exhaust gas recirculation. External exhaust gas recirculation involves re-introducing a portion of the emitted exhaust gas into the engine intake manifold after intercooling, thereby reducing combustion temperature and nitrogen oxide emissions. Internal exhaust gas recirculation, on the other hand, involves controlling the valve mechanism to re-intake or retain exhaust gas in the cylinder, thereby increasing the temperature of the air-fuel mixture and promoting combustion.

[0066] Methanol cracking technology refers to the chemical reaction in which methanol molecules are heated to a high temperature and decomposed into carbon monoxide and hydrogen under the action of a catalyst.

[0067] Methanol, with its low carbon content, high octane number, high oxygen content, low pollution, and smokeless emissions, has gradually been recognized by the shipping industry as an ideal new type of clean and renewable fuel. Currently, the mainstream application of methanol fuel in marine engines is the DMCC (Diesel-Modulated Combustion-Cylinder Mixture) mode, where methanol is injected through the intake manifold and diesel fuel is directly injected to ignite the methanol-air mixture. However, in the DMCC mode, the methanol substitution rate is severely limited by operating conditions, making it difficult to achieve a high methanol substitution rate across a wide range of operating conditions while ensuring reliable ignition and stable combustion. Furthermore, methanol has a high latent heat of vaporization, a fast flame propagation speed, and complex interactions with diesel fuel. Under low loads, excessive fuel-air mixing is likely, while under high loads, coarse combustion is prone to occur. Achieving clean, efficient, and controllable combustion across the entire operating range is challenging. Therefore, these technical problems urgently need to be addressed.

[0068] Based on this, one embodiment of the present invention provides a marine dual direct injection engine system that enables clean, efficient, and controllable combustion of the engine over a wide operating range, effectively alleviating the problem of limited operating conditions. (Refer to...) Figure 1In this specific embodiment, the marine dual direct injection engine system includes a methanol supply module, a diesel supply module, an engine, a methanol cracking module, and an exhaust gas recirculation module. Specifically, in this embodiment, the methanol supply module supplies methanol to the engine and the methanol cracking module. Additionally, in this embodiment, the diesel supply module supplies diesel fuel to the engine. Accordingly, in this embodiment, the engine includes an intake manifold 171, an exhaust manifold 172, and a fuel input terminal. Both the methanol supply module and the diesel supply module are connected to the engine's fuel input terminal to input methanol from the methanol supply module and diesel fuel from the diesel supply module into the engine for combustion. Further, in this embodiment, the methanol cracking module includes a cracking input terminal and a cracking output terminal. The methanol cracking input terminal is connected to the methanol supply module to introduce methanol stored in the methanol supply module into the methanol cracking module for methanol cracking reaction, producing a methanol cracking mixed gas, such as a hydrogen and carbon monoxide mixed gas. Accordingly, in this embodiment, the cracking output terminal of the methanol cracking module is connected to the engine's intake manifold 171 to introduce the cracked methanol cracking mixed gas into the engine, thereby achieving hydrogen-blended combustion and accelerating the combustion speed. In addition, the methanol cracking module in this embodiment of the invention also includes a methanol cracking reactor 190 and a catalyst pipeline 191. Methanol from the methanol supply module is input into the methanol cracking reactor 190 through a third shut-off valve 143 and a methanol branch flow meter 210, and combined with the cracking reaction catalyst provided by the catalyst pipeline 191, thereby realizing the methanol cracking reaction and generating methanol cracked gas. Further, the exhaust gas recirculation module in this embodiment of the invention includes an exhaust gas input end, a first exhaust gas output pipeline 221, and a second exhaust gas output pipeline 223. Specifically, in this embodiment of the invention, the exhaust gas input end is connected to the exhaust manifold 172 of the engine to introduce the exhaust gas generated by combustion in the engine into the exhaust gas recirculation module. In this embodiment of the invention, the waste heat of the exhaust gas passing through the first exhaust gas output pipeline of the methanol cracking module provides heat for the methanol cracking reaction in the methanol cracking module. At the same time, in this embodiment of the invention, the first exhaust gas output pipeline 221 is connected to the intake manifold 171 to reintroduce part of the exhaust gas into the engine, thereby forming external exhaust gas recirculation. By introducing part of the cooled exhaust gas into the engine, it participates in the engine's combustion cycle and regulates the combustion rate. In addition, in this embodiment of the invention, the first exhaust gas output pipe 221, besides being connected to the exhaust manifold 172, is also provided with an exhaust branch to discharge exhaust gases other than the portion of exhaust gases introduced into the engine from the first exhaust gas output pipe 221. Meanwhile, in this embodiment of the invention, the second exhaust gas output pipe is used to discharge exhaust gases generated by the engine.

[0069] In this specific embodiment, the present invention controls the methanol supply module and the diesel supply module to regulate the combustion mode and fuel ratio according to the injection timing of methanol and diesel, thereby adapting to the power requirements of different navigation conditions. Simultaneously, the present invention introduces an exhaust gas recirculation module, including internal and external EGR, and a methanol cracking module, i.e., methanol cracking technology, which can effectively improve combustion efficiency under different operating conditions and reduce conventional and unconventional emissions. In this embodiment, external exhaust gas recirculation is achieved through the piping configuration of the exhaust gas recirculation module, while internal exhaust gas recirculation is achieved by controlling the valve timing. For example, in the cold start first cycle stage, the present invention operates in pure diesel mode, which can alleviate the difficulty of methanol cold start. Correspondingly, under low load conditions, the present invention applies a methanol mixed limited combustion mode (MMLC) and introduces internal thermal EGR to improve the in-cylinder thermodynamic state, increase exhaust temperature, and simultaneously utilize the waste heat of engine exhaust to achieve methanol cracking and hydrogen blending, accelerating the combustion rate. Furthermore, under medium-load conditions, this embodiment of the invention, by applying a homogeneous charge premixed combustion mode (MHCC) combined with external EGR and methanol cracking technology, can regulate the combustion rate while achieving a high methanol substitution rate. Next, under high-load conditions, this embodiment of the invention, by applying a partially premixed combustion mode (MPCC), and through premixing ratio control and external EGR technology, can achieve controllable combustion under high loads. This embodiment of the invention, by controlling and adjusting the methanol supply module, diesel supply module, methanol cracking module, and exhaust gas recirculation module based on engine speed and power information, can achieve clean, efficient, and controllable combustion over a wide operating range, effectively alleviating the problem of limited operating conditions.

[0070] Reference Figure 1In some embodiments of the present invention, the methanol supply module includes a methanol tank 111, a methanol flow meter 121, a preset methanol pump 131, a first shut-off valve 141, a methanol common rail submodule 151, and a preset methanol injector 161. Specifically, in this embodiment, the methanol tank 111 is used to store and output methanol. Correspondingly, in this embodiment, the preset methanol pump 131 includes a methanol pump input end and a methanol pump output end, and the methanol pump input end is connected to the methanol tank 111. Accordingly, in this embodiment, the methanol in the methanol tank 111 is input to the engine through the preset methanol pump 131, that is, the methanol in the methanol tank 111 is pumped into the pipeline by the preset methanol pump 131, and then input to the engine. Further, in this embodiment, the first shut-off valve 141 includes a first shut-off input end and a first shut-off output end, wherein the first shut-off input end is connected to the methanol pump output end of the preset methanol pump 131. In this embodiment, the first shut-off valve 141 controls the first working state of the methanol supply module. For example, when the first shut-off valve 141 is open, methanol in the methanol supply module can be normally input into the engine, i.e., it is in a working state. When the first shut-off valve 141 is closed, methanol in the methanol supply module cannot be input into the engine, i.e., it is in a closed state. Accordingly, in this embodiment of the invention, the methanol flow meter 121 includes a first flow meter input terminal and a first flow meter output terminal, and the first flow meter input terminal is connected to the first flow meter output terminal of the methanol flow meter 121. In this embodiment of the invention, the methanol flow meter 121 measures and adjusts the methanol output of the methanol tank 111. Further, in this embodiment of the invention, the methanol common rail submodule 151 includes a first common rail input terminal and a first common rail output terminal. The first common rail input terminal is connected to the first flow meter output terminal. In this embodiment of the invention, the methanol common rail submodule 151 controls and adjusts the methanol output state. For example, in this embodiment of the invention, the methanol common rail submodule 151 controls the working pressure of the preset methanol pump 131 to ensure the stability and accuracy of fuel supply, thereby improving the combustion efficiency and performance of the engine. Furthermore, in this embodiment of the invention, methanol from the methanol common rail submodule 151 is injected into the engine cylinder via a preset methanol injector 161. Specifically, the preset methanol injector 161 includes a methanol injection end and a first injector input end. The first injector input end is connected to the first common rail output end of the methanol common rail submodule 151 to guide methanol from the methanol common rail submodule 151 into the preset methanol injector 161, and then inject the methanol into the engine cylinder 170 via the methanol injection end.

[0071] Reference Figure 1In some embodiments of the present invention, the diesel supply module includes a diesel tank 112, a diesel flow meter 122, a preset diesel pump 132, a second shut-off valve 142, a diesel common rail submodule 152, and a preset diesel injector 162. Specifically, the present invention stores and outputs diesel fuel through the diesel tank 112. Next, the preset diesel pump 132 in the present invention includes a diesel pump input end and a diesel pump output end, and the diesel pump input end is connected to the diesel tank 112 to provide pressure to the diesel tank 112, pumping diesel fuel into the pipeline and then into the engine. Further, the second shut-off valve 142 in the present invention includes a second shut-off input end and a second shut-off output end. The second shut-off input end in the present invention is connected to the diesel pump output end of the preset diesel pump 132 to control a second operating state of the diesel supply module through the second shut-off valve 142. For example, the present invention controls the operating state of the diesel supply module by controlling the opening and closing of the second shut-off valve 142. In addition, in this embodiment of the invention, the diesel flow meter 122 includes a second flow meter input terminal and a second flow meter output terminal, and the second flow meter input terminal is connected to the second cut-off output terminal of the second cut-off valve 142. In this embodiment of the invention, the diesel flow meter 122 measures and regulates the diesel output of the diesel tank 112. Further, in this embodiment of the invention, the diesel common rail submodule 152 includes a second common rail input terminal and a second common rail output terminal. In this embodiment of the invention, the second common rail input terminal is connected to the second flow meter output terminal of the diesel flow meter 122. Accordingly, in this embodiment of the invention, the diesel common rail submodule 152 controls and regulates the diesel output state. The diesel common rail submodule 152 controls the preset working pressure of the diesel pump 132 to ensure the stability and accuracy of fuel supply, thereby improving the combustion efficiency and performance of the engine. Simultaneously, in this embodiment of the invention, the diesel common rail submodule 152 and the methanol common rail submodule 151 can also control the mixing of fuel and air by controlling the injection time and amount of the fuel injectors according to the engine operating conditions and load requirements, thereby optimizing the combustion process, reducing emissions, and improving fuel utilization. Furthermore, in this embodiment of the invention, the preset diesel injector 162 includes a diesel injection end and a second injector input end. In this embodiment, the second injector input end is connected to the second common rail output end of the diesel common rail submodule 152 to input diesel fuel from the diesel common rail submodule 152 into the preset diesel injector, and then inject the diesel fuel into the engine cylinder 170 through the diesel injection end.

[0072] Reference Figure 1In some embodiments of the present invention, the marine dual direct injection engine system provided by the present invention further includes a turbocharger 180, an exhaust gas-air mixer 230, a methanol cracking gas mixer 240, and an intercooler 250. Specifically, in the embodiments of the present invention, the turbocharger 180 includes a first intake end, a first outlet end, a second intake end, and a second outlet end. In the embodiments of the present invention, the turbocharger 180 inputs air through the first intake end, i.e., obtains air. Correspondingly, in the embodiments of the present invention, the second intake end is connected to the second exhaust gas output pipeline of the exhaust gas recirculation module to utilize the energy of the exhaust gas to drive the turbocharger, causing it to rotate and compress the intake air, thereby increasing the intake pressure and density of the engine and improving the engine efficiency and performance. Next, in the embodiments of the present invention, the compressed air is input into the exhaust gas-air mixer 230 through the first outlet end. In the embodiments of the present invention, the exhaust gas-air mixer 230 includes a first mixing input end, a second mixing input end, and a first mixing output end. Accordingly, in this embodiment of the invention, the first mixing input terminal is connected to the first outlet terminal of the turbocharger 180, and the second mixing input terminal is connected to the first exhaust gas output pipeline through the exhaust gas recirculation valve 222, so that the air obtained by the turbocharger 180 and the cooled exhaust gas are mixed through the exhaust gas-air mixer 230 to obtain the first mixed gas. Next, in this embodiment of the invention, the first mixed gas is input into the methanol cracking gas mixer 240 through the first mixing output terminal of the exhaust gas-air mixer 230 for further mixing with the gas obtained from cracking. In this embodiment of the invention, the methanol cracking gas mixer 240 includes a third mixing input terminal, a fourth mixing input terminal, and a second mixing output terminal. Accordingly, in this embodiment of the invention, the third mixing input terminal is connected to the first mixing output terminal of the exhaust gas-air mixer 230, and the fourth mixing input terminal is connected to the cracking output terminal of the methanol cracking module through the cracking gas valve 193, forming the cracking gas pipeline 192. In this embodiment of the invention, a first mixed gas and methanol cracked gas are mixed through a methanol cracking gas mixer 240 to obtain a target mixed gas, which is then input into the engine to achieve hydrogen-blended combustion, realizing clean, efficient, and controllable combustion over a wide operating range. Furthermore, after obtaining the target mixed gas, this embodiment first inputs the target mixed gas into an intercooler 250 to cool it. The intercooler 250 includes an intercooler input end and an intercooler output end. The intercooler input end is connected to the second mixing output end of the methanol cracking gas mixer 240, and the intercooler output end is connected to the engine's intake manifold 171, thereby introducing the cooled target mixed gas into the engine.

[0073] Reference Figure 2One embodiment of the present invention provides a control method for a marine dual direct injection engine system, which enables clean, efficient, and controllable combustion of the engine over a wide operating range, effectively alleviating the problem of limited operating conditions. The method of this embodiment includes, but is not limited to, steps S310, S320, and S330.

[0074] Specifically, the application of the method of this invention to the above-described marine dual direct injection engine system includes, but is not limited to, the following steps:

[0075] S310: Obtain preset engine parameters, wherein the preset engine parameters include engine speed, engine desired power, and engine rated power.

[0076] S320: Determines the engine operating mode based on engine speed, desired engine power, and rated engine power.

[0077] S330: Controls the operating status of preset control modules according to the engine operating mode to adjust the engine's operating state. These preset control modules include a methanol cracking module, an exhaust gas recirculation module, a methanol supply module, and a diesel supply module.

[0078] In this specific embodiment, the present invention first obtains preset engine parameters to determine the corresponding engine operating mode based on the preset engine parameters. Then, it controls the working state of the preset control module according to the engine operating mode, thereby adjusting the engine combustion mode to achieve clean, efficient, and controllable combustion over a wide operating range, effectively alleviating the problem of limited operating conditions. Specifically, the preset engine parameters in this embodiment include engine speed, desired engine power, and rated engine power. The present invention determines the engine operating mode, such as cold start mode, low load mode, medium load mode, and high load mode, based on the relationship between engine speed, desired engine power, and rated engine power. Further, the present invention adjusts the working state of preset control modules, such as the methanol cracking module, exhaust gas recirculation module, methanol supply module, and diesel supply module, according to the determined engine operating mode, thereby adjusting the engine operating state, such as adjusting the engine combustion mode, such as methanol mixed limited combustion (MMLC) mode, methanol homogeneous charge premixed combustion (MHCC) mode, and methanol partially premixed combustion (MPCC) mode. Specifically, in adjusting the engine operating state, this embodiment of the invention adjusts the working states of the methanol supply module and the diesel supply module, i.e., adjusts the injection timing of methanol and diesel, to adjust the engine combustion mode. Simultaneously, it adjusts the working states of the methanol cracking module and the exhaust gas recirculation module to assist in regulating the in-cylinder combustion process. It is readily understood that this embodiment of the invention, by determining the corresponding engine operating mode based on preset engine parameters and then adjusting the working states of preset control modules, can achieve the adjustment and control of the engine operating state. This enables clean, efficient, and controllable combustion over a wide operating range, effectively alleviating the problem of limited operating conditions.

[0079] In some embodiments of the present invention, the engine operating mode is determined based on engine speed, desired engine power, and rated engine power, including but not limited to the following steps:

[0080] When the engine speed is determined to be zero, the engine operating mode is set to cold start mode.

[0081] Alternatively, when it is determined that the engine speed is not zero and the engine's expected power is less than or equal to a first threshold of the engine's rated power, the engine operating mode is determined to be a low-load operating mode.

[0082] Alternatively, when it is determined that the engine speed is not zero, the engine's expected power is greater than the first threshold, and the engine's expected power is less than or equal to the second threshold of the engine's rated power, the engine operating mode is determined to be the medium load operating mode.

[0083] Alternatively, when it is determined that the engine speed is not zero and the expected engine power is greater than the second threshold, the engine operating mode is determined to be the high load operating mode.

[0084] In this specific embodiment, the present invention determines the corresponding engine operating mode by considering the relationship between engine speed and the engine's desired power and rated power. Specifically, the present invention first determines whether the engine speed is zero. When the engine speed is zero, the engine is considered to be in a cold start state, and the engine is determined to have entered the cold start first cycle mode, i.e., the engine operating mode is determined to be the cold start operating mode. Conversely, when the engine speed is not zero, the present invention determines the relationship between the engine's rated power and the engine's desired power to further determine the engine's operating mode. Accordingly, when the engine's desired power is less than a first threshold of the engine's rated power, the engine operating mode is determined to be a low-load operating mode. For example, when the engine speed is not zero, and the engine's desired power is less than or equal to 40% of the engine's rated power, the engine is determined to be in a low-load operating mode. Further, when the engine speed is not zero, and the engine's desired power is greater than the first threshold of the engine's rated power, and the engine's desired power is less than or equal to a second threshold of the engine's rated power, the present invention determines the engine operating mode to be a medium-load operating mode. For example, when it is determined that the engine speed is not zero, and the expected engine power is greater than 40% of the engine's rated power but less than or equal to 70% of the engine's rated power (i.e., 40% of the engine's rated power < expected engine power ≤ 70% of the engine's rated power), this embodiment of the invention determines that the engine is in a medium-load operating mode, i.e., a medium-load operating condition mode. Further, when it is determined that the engine speed is not zero, and the expected engine power is greater than a second threshold, this embodiment of the invention determines that the engine operating mode is a high-load operating mode. For example, when it is determined that the engine speed is not equal to 0, and 70% of the engine's rated power < expected engine power ≤ 100% of the engine's rated power, this embodiment of the invention determines that the engine is in a high-load operating mode, i.e., a high-load operating condition mode. It should be noted that in this embodiment of the invention, the expected engine power refers to the power required by the engine determined by the controller ECU based on conditions such as water flow speed, water flow direction, and navigation direction.

[0085] In some embodiments of the present invention, the operating state of a preset control module is controlled according to the engine operating mode to adjust the engine operating state, including but not limited to the following steps:

[0086] When the engine operating mode is determined to be cold start mode, the exhaust gas recirculation module is turned off, and the diesel supply module is controlled to output diesel to the engine.

[0087] The methanol supply module controls the output of methanol to the methanol cracking module to carry out the methanol cracking reaction, obtain methanol cracked gas, and input the methanol cracked gas into the engine.

[0088] In this specific embodiment, when the engine operating mode is cold start mode, the exhaust gas recirculation module is shut down. Correspondingly, the diesel supply module is activated to control the diesel supply module to output diesel fuel to the engine. Simultaneously, the methanol supply module and methanol cracking module are activated, controlling the methanol supply module to output methanol to the methanol cracking module for methanol cracking reaction, obtaining methanol cracked gas, which is then input into the engine for cold start in pure diesel mode. Exemplarily, during the first cycle of cold start operation, i.e., in cold start mode, in the methanol supply circuit, the methanol tank is first opened, and methanol enters the catalyst pipeline via a preset methanol pump, a third shut-off valve, and a methanol branch flow meter. Next, the diesel supply module is activated, opening the diesel tank in the diesel supply circuit. Diesel fuel enters the engine cylinder via a preset diesel injector through a diesel flow meter, a preset diesel pump, a second shut-off valve, and a diesel common rail submodule. Additionally, in the intake circuit, filtered air enters the engine cylinder via the intake manifold through the turbocharger, exhaust gas-air mixer, methanol cracked gas mixer, and intercooler. Accordingly, in the exhaust circuit of this embodiment of the invention, the exhaust gas after combustion enters the turbocharger directly through the exhaust manifold and the methanol cracking reactor and is discharged.

[0089] In some embodiments of the present invention, the operation state of a preset control module is controlled according to the engine operating mode to adjust the engine operating state, and the following steps are included but not limited to:

[0090] When the engine operating mode is determined to be low load operating mode, the methanol cracking module, diesel supply module and methanol supply module are turned on.

[0091] Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in the methanol-mixed limited combustion mode.

[0092] The first injection parameters, methanol cracking hydrogen production rate, and methanol energy ratio are adjusted based on the first preset output parameters. The first preset output parameters include engine exhaust temperature and engine load requirements, while the first injection parameters include methanol injection timing and diesel injection timing.

[0093] The engine intake valves are opened a second time according to a preset valve control law to perform internal exhaust gas recirculation.

[0094] In this specific embodiment, when the engine operating mode is low-load operating mode, the present invention first controls the methanol cracking module, diesel supply module, and methanol supply module to open, then adjusts the injection timing of the diesel supply module and methanol supply module to control the engine to operate in methanol mixed limited combustion (MMLC) mode, and controls the opening of the engine's intake valve according to a preset valve control law to achieve secondary opening of the intake valve, so that some exhaust gas remains in the cylinder, forming internal exhaust gas recirculation (EGR). Specifically, refer to... Figure 3 and Figure 4 When operating under low load conditions, this embodiment of the invention controls the methanol supply module, diesel supply module, and methanol cracking gas pipeline (i.e., the methanol cracking module) to be turned on via the controller ECU, and shuts off the external EGR pipeline (i.e., the exhaust gas recirculation module). Then, it controls the methanol and diesel injection timing to achieve methanol mixed restricted combustion (MMLC) mode. Figure 3 As shown. Simultaneously, in this embodiment of the invention, the valve generation pattern is altered via the controller ECU to cause the intake valve to open a second time, as... Figure 4As shown. In this embodiment of the invention, the valve control law, i.e., the preset valve control law, refers to the law controlling the timing, duration, and speed of valve opening and closing. Next, this embodiment adjusts the first injection parameters, methanol cracking hydrogen production rate, and methanol energy ratio according to the first preset output parameters. Specifically, the first preset output parameters in this embodiment include engine exhaust temperature and engine load requirements, and the first injection parameters include methanol injection timing and diesel injection timing. Under low load conditions, the methanol injection timing, diesel injection timing, methanol energy ratio, and methanol cracking hydrogen production rate in this embodiment are all controlled by the controller ECU based on feedback from the engine exhaust temperature and engine load requirements. Correspondingly, in the methanol mixed limited combustion (MMLC) mode, this embodiment controls the methanol energy ratio within a first energy ratio range through the controller ECU, such as a methanol energy ratio between 50% and 80%, with the remaining energy supplied by ignition diesel. In this embodiment, the controller ECU adjusts the power by increasing the total energy of methanol and diesel. It should be noted that the engine combustion mode in this embodiment is controlled by the injection timing, and each load corresponds to a combustion mode. Accordingly, embodiments of the present invention utilize methanol cracking and exhaust gas recirculation to assist in combustion regulation (optimize the in-cylinder combustion process). For example, under low-load operating conditions, embodiments of the present invention activate the methanol cracking module and deactivate the exhaust gas recirculation module, i.e., the EGR pipeline. In these embodiments, the diesel supply circuit is consistent with the cold start first-cycle mode. Furthermore, in the methanol supply circuit of these embodiments, the methanol tank is first opened, allowing a portion of methanol to enter the engine cylinder via a methanol flow meter, a preset methanol pump, a first shut-off valve, a methanol common rail submodule, and a preset methanol injector; another portion of methanol enters the catalyst pipeline via a third shut-off valve and a methanol branch flow meter. In the intake circuit of these embodiments, filtered air passes through the turbocharger, exhaust gas-air mixer, methanol cracking gas mixer, and intercooler, and enters the engine cylinder via the intake manifold. In the exhaust circuit of these embodiments, the combusted exhaust gas passes through the exhaust manifold and the methanol cracking reactor, and is discharged through the turbocharger. It should be noted that in the embodiments of the present invention, the exhaust gas does not participate in the methanol cracking reaction. It only uses residual heat to heat the catalyst in the catalyst pipeline to promote the occurrence of the methanol cracking reaction. The methanol cracking gas enters the methanol cracking gas mixer after passing through the cracking gas pipeline, that is, the cracking output end and the cracking gas valve, and is fully mixed with air. At this time, the exhaust gas circulation valve is in the closed state.

[0095] In some embodiments of the present invention, the operation state of a preset control module is controlled according to the engine operating mode to adjust the engine operating state, and the following steps are included but not limited to:

[0096] When the engine operating mode is determined to be medium load operating mode, the exhaust gas recirculation module, methanol cracking module, diesel supply module and methanol supply module are turned on.

[0097] Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in the methanol homogeneous charge premixed combustion mode.

[0098] The first injection parameters, methanol cracking hydrogen production rate, methanol energy ratio, and exhaust gas recirculation rate are adjusted based on the second preset output parameters. The second preset output parameters include engine load requirements, knock output feedback, and knock pressure output feedback. The first injection parameters include methanol injection timing and diesel injection timing.

[0099] In this specific embodiment, when the engine operating mode is medium load mode, the embodiment of the present invention first controls the exhaust gas recirculation module, methanol cracking module, diesel supply module, and methanol supply module to start. Then, it adjusts the injection timing of the diesel supply module and methanol supply module to control the engine to operate in methanol homogeneous charge premixed combustion (MHCC) mode. Specifically, refer to... Figure 5In this embodiment of the invention, the methanol supply module, diesel supply module, external EGR pipeline, and methanol cracking gas pipeline are controlled by the ECU (Electronic Control Unit), namely the exhaust gas recirculation module and the methanol cracking module, and the methanol and diesel injection timing is controlled to achieve a homogeneous charge premixed combustion (MHCC) mode. Specifically, this embodiment controls the engine to operate in MHCC mode by adjusting the injection timing of the diesel and methanol supply modules, i.e., controlling the methanol injection time and diesel injection time. Next, this embodiment adjusts the first injection parameters, methanol cracking hydrogen production rate, methanol energy ratio, and exhaust gas recirculation rate according to the second preset output parameters. Specifically, the second preset output parameters include engine load demand, knock output feedback, and knock pressure output feedback; the first injection parameters include methanol injection time and diesel injection time. Under medium load conditions, in this embodiment, the methanol energy ratio, diesel injection time, methanol injection time, methanol cracking hydrogen production rate, and external exhaust gas recirculation rate are all regulated by the ECU based on engine load demand, knock pressure output feedback, and knock output feedback. For example, in the methanol homogeneous charge premixed combustion (MHCC) mode, in this embodiment of the invention, the energy ratio of methanol is controlled by the controller ECU between 60% and 90%, with the remaining energy supplied by the ignition diesel. Exemplarily, in the medium-load operating mode, both the methanol cracking module and the exhaust gas recirculation module in this embodiment of the invention are activated. The intake circuit and methanol / diesel supply circuits in this embodiment of the invention are consistent with those in the low-load mode. Correspondingly, in the exhaust circuit of this embodiment of the invention, the exhaust gas after combustion passes through the exhaust manifold, the methanol cracking reactor, and enters the turbocharger for discharge. Additionally, some of the exhaust gas passing through the methanol cracking reactor is affected by the pressure difference and enters the exhaust gas-air mixer through the exhaust gas recirculation pipeline, i.e., the first exhaust gas output pipeline and the exhaust gas recirculation valve, where it is fully mixed with air. It should be noted that in this embodiment of the invention, the exhaust gas does not participate in the methanol cracking reaction; it only utilizes residual heat to heat the catalyst in the catalyst pipeline to promote the methanol cracking reaction. The methanol cracked gas passes through the cracked gas pipeline, i.e., the cracked gas output end and the cracked gas valve, and then enters the methanol cracked gas mixer to fully mix with air and exhaust gas.

[0100] In some embodiments of the present invention, the operation state of a preset control module is controlled according to the engine operating mode to adjust the engine operating state, and the following steps are included but not limited to:

[0101] When the engine operating mode is determined to be high load mode, the exhaust gas recirculation module, diesel supply module and methanol supply module are activated.

[0102] Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol partially premixed combustion mode.

[0103] The second injection parameters and exhaust gas recirculation rate are adjusted based on the third preset output parameters. The third preset output parameters include engine load requirements, knock output feedback, and knock pressure output feedback. The second injection parameters include the methanol primary injection ratio, methanol secondary injection ratio, methanol injection timing, and diesel injection timing.

[0104] In this specific embodiment, when the engine operating mode is high-load mode, the present invention first controls the exhaust gas recirculation module, diesel supply module, and methanol supply module to start. By adjusting the injection timing of the diesel supply module and methanol supply module, the engine is controlled to operate in methanol partially premixed combustion (MPCC) mode. Specifically, refer to... Figure 6 In this embodiment of the invention, the ECU controls the activation of the methanol supply module, diesel supply module, and external EGR pipeline (i.e., the exhaust gas recirculation module), while shutting down the methanol cracking gas pipeline (i.e., the methanol cracking module). This allows for the implementation of a partially premixed methanol combustion (MPCC) mode by controlling the injection timing of methanol and diesel. For example, in this embodiment, the ECU controls the energy ratio of methanol to be between 60% and 80%, with the remaining energy supplied by ignition diesel. Specifically, the ECU adjusts power by increasing the total energy of methanol and diesel. Furthermore, this embodiment adjusts the second injection parameters and the exhaust gas recirculation rate based on a third preset output parameter. The third preset output parameter includes knock output feedback, knock pressure output feedback, and engine load requirements. The second injection parameters include the methanol primary injection ratio, methanol secondary injection ratio, methanol injection timing, and diesel injection timing. In the Methanol Partial Premixed Combustion (MPCC) mode, the ratio of primary and secondary methanol injections, the methanol injection timing, the diesel injection timing, and the exhaust gas recirculation rate are all controlled by the ECU based on engine load requirements, knock pressure, and knock output feedback. For example, in the high-load operating mode, this embodiment of the invention shuts down the methanol cracking module and turns on the exhaust gas recirculation module. Correspondingly, the intake circuit and diesel supply circuit in this embodiment are consistent with those in the low-load and medium-load operating modes. Specifically, in the methanol supply circuit of this embodiment, methanol enters the engine cylinder via a methanol flow meter, a preset methanol pump, a first shut-off valve, a methanol common rail submodule, and a preset methanol injector. Correspondingly, in the exhaust circuit of this embodiment, the exhaust gas after combustion passes through the exhaust manifold, the methanol cracking reactor, and enters the turbocharger for discharge. Additionally, a portion of the exhaust gas passing through the methanol cracking reactor is affected by the pressure difference and enters the exhaust gas-air mixer via the EGR pipeline, i.e., the first exhaust gas pipeline and the exhaust gas recirculation valve, to be fully mixed with air. At this time, the cracked gas valve is in the closed state.

[0105] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0106] The above is a detailed description of the preferred embodiments of the present invention. However, the present invention is not limited to the above embodiments. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention. All such equivalent modifications or substitutions are included within the scope defined by the claims of the present invention.

Claims

1. A marine dual direct injection engine system, characterized in that, include: A methanol supply module for injecting methanol into the cylinders of the engine; A diesel supply module for injecting diesel fuel into the cylinders of the engine; An engine, comprising an intake manifold, an exhaust manifold, and a fuel input terminal, wherein the fuel input terminal is connected to the methanol supply module and the diesel supply module respectively, and the engine is used to burn the input diesel and methanol; A methanol cracking module, comprising a cracking input end, a cracking output end, a methanol cracking reactor, and a catalyst pipeline; The cracking input terminal is connected to the methanol supply module to input the methanol supplied by the methanol supply module into the methanol cracking reactor; the cracking output terminal is connected to the intake manifold, and the methanol cracking reactor is used to use the exhaust heat of the engine combined with the cracking reaction catalyst provided by the catalyst pipeline to crack the input methanol to obtain methanol cracked gas, which is then input into the engine through the intake manifold. The exhaust gas recirculation module includes an exhaust gas input terminal, a first exhaust gas output pipeline, and a second exhaust gas output pipeline. The exhaust gas input terminal is connected to the exhaust manifold through the methanol cracking module. The first exhaust gas output pipeline is connected to the intake manifold. The second exhaust gas output pipeline is used to discharge the exhaust gas generated by the engine.

2. The marine twin direct injection engine system according to claim 1, characterized in that, The methanol supply module includes: A methanol tank for storing and discharging the methanol; A preset methanol pump is provided, which includes a methanol pump input terminal and a methanol pump output terminal. The methanol pump input terminal is connected to the methanol tank. The preset methanol pump is used to provide pressure to the methanol tank so as to output the methanol in the methanol tank. The first shut-off valve includes a first shut-off input terminal and a first shut-off output terminal. The first shut-off input terminal is connected to the output terminal of the methanol pump. The first shut-off valve is used to control the first working state of the methanol supply module. A methanol flow meter, comprising a first flow meter input terminal and a first flow meter output terminal, wherein the first flow meter input terminal is connected to a first cutoff output terminal, and the methanol flow meter is used to measure and regulate the output of methanol. A methanol common rail submodule includes a first common rail input terminal and a first common rail output terminal. The first common rail input terminal is connected to the output terminal of the first flow meter. The methanol common rail submodule is used to control and regulate the methanol output state. A preset methanol injector includes a methanol injection end and a first injector input end, the first injector input end being connected to a first common rail output end, and the methanol injection end being used to inject methanol into the cylinder of the engine.

3. The marine twin direct injection engine system according to claim 1, characterized in that, The diesel supply module includes: A diesel tank for storing and discharging diesel fuel; A preset diesel pump, comprising a diesel pump input end and a diesel pump output end, wherein the diesel pump input end is connected to the diesel tank, and the preset diesel pump is used to provide pressure to the diesel tank to output diesel fuel from the diesel tank; The second shut-off valve includes a second shut-off input terminal and a second shut-off output terminal. The second shut-off input terminal is connected to the output terminal of the diesel pump. The second shut-off valve is used to control the second working state of the diesel supply module. A diesel flow meter, comprising a second flow meter input terminal and a second flow meter output terminal, wherein the second flow meter input terminal is connected to a second cut-off output terminal, and the diesel flow meter is used to measure and regulate the output of diesel fuel. A diesel common rail submodule includes a second common rail input terminal and a second common rail output terminal. The second common rail input terminal is connected to the output terminal of the second flow meter. The diesel common rail submodule is used to control and regulate the diesel output status. A preset diesel injector includes a diesel injection end and a second injector input end, the second injector input end being connected to a second common rail output end, and the diesel injection end being used to inject the diesel fuel into the cylinder of the engine.

4. The marine dual direct injection engine system according to claim 1, characterized in that, The system also includes: A turbocharger, comprising a first intake end, a first outlet end, a second intake end, and a second outlet end, wherein the second intake end is connected to a second exhaust gas output pipeline, the first intake end is used to input air, and the second outlet end is used to discharge exhaust gas. An exhaust gas-air mixer includes a first mixing input terminal, a second mixing input terminal, and a first mixing output terminal. The first mixing input terminal is connected to a first air outlet terminal, and the second mixing input terminal is connected to the first exhaust gas output pipeline through an exhaust gas recirculation valve. The exhaust gas-air mixer is used to mix the air obtained by the turbocharger with the exhaust gas to obtain a first mixed gas. A methanol cracking gas mixer includes a third mixing input terminal, a fourth mixing input terminal, and a second mixing output terminal. The third mixing input terminal is connected to the first mixing output terminal, and the fourth mixing input terminal is connected to the cracking output terminal through a cracking gas valve. The methanol cracking gas mixer is used to mix the first mixed gas with the methanol cracking gas to obtain a target mixed gas. An intercooler, comprising an intercooler input terminal and an intercooler output terminal, wherein the intercooler input terminal is connected to the second mixing output terminal and the intercooler output terminal is connected to the intake manifold, and the intercooler is used to cool the target gas mixture.

5. A control method for a marine dual direct injection engine system, characterized in that, The method is applied to the marine dual direct injection engine system of claim 1, comprising: Obtain preset engine parameters, wherein the preset engine parameters include engine speed, engine desired power, and engine rated power; The engine operating mode is determined based on the engine speed, the desired engine power, and the rated engine power. The operating state of the preset control module is adjusted according to the engine operating mode; wherein, the preset control module includes a methanol cracking module, an exhaust gas recirculation module, a methanol supply module, and a diesel supply module.

6. The control method for a marine dual direct injection engine system according to claim 5, characterized in that, The step of determining the engine operating mode based on the engine speed, the desired engine power, and the rated engine power includes: When the engine speed is determined to be zero, the engine operating mode is determined to be cold start operating mode; Alternatively, when it is determined that the engine speed is not zero and the engine's expected power is less than or equal to a first threshold of the engine's rated power, the engine operating mode is determined to be a low-load operating mode. Alternatively, when it is determined that the engine speed is not zero, the engine's expected power is greater than the first threshold, and the engine's expected power is less than or equal to the second threshold of the engine's rated power, the engine operating mode is determined to be a medium load operating mode. Alternatively, when it is determined that the engine speed is not zero and the engine's expected power is greater than the second threshold, the engine operating mode is determined to be a high-load operating mode.

7. The control method for a marine dual direct injection engine system according to claim 6, characterized in that, The step of controlling the operating state of the preset control module according to the engine operating condition mode to adjust the engine operating state includes: When the engine operating mode is determined to be the cold start operating mode, the exhaust gas recirculation module is turned off, and the diesel supply module is controlled to output diesel to the engine. The methanol supply module is controlled to output methanol to the methanol cracking module for methanol cracking reaction to obtain methanol cracked gas, and the methanol cracked gas is input into the engine.

8. The control method for a marine dual direct injection engine system according to claim 6, characterized in that, The step of controlling the operating state of the preset control module according to the engine operating mode to adjust the engine operating state also includes: When the engine operating mode is determined to be the low load operating mode, the methanol cracking module, the diesel supply module, and the methanol supply module are controlled to be turned on. Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol-mixed restricted combustion mode; The first injection parameters, methanol cracking hydrogen production rate, and methanol energy ratio are adjusted according to the first preset output parameters; wherein, the first preset output parameters include engine exhaust temperature and engine load requirements, and the first injection parameters include methanol injection timing and diesel injection timing. The intake valve of the engine is opened a second time according to a preset valve control law to perform internal exhaust gas recirculation.

9. The control method for a marine dual direct injection engine system according to claim 6, characterized in that, The step of controlling the operating state of the preset control module according to the engine operating mode to adjust the engine operating state also includes: When the engine operating mode is determined to be the medium load operating mode, the exhaust gas recirculation module, the methanol cracking module, the diesel supply module, and the methanol supply module are controlled to be turned on. Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in the methanol homogeneous charge premixed combustion mode; The first injection parameters, methanol cracking hydrogen production rate, methanol energy ratio, and exhaust gas recirculation rate are adjusted according to the second preset output parameters; wherein, the second preset output parameters include engine load demand, knock output feedback, and knock pressure output feedback, and the first injection parameters include methanol injection timing and diesel injection timing.

10. The control method for a marine dual direct injection engine system according to claim 6, characterized in that, The step of controlling the operating state of the preset control module according to the engine operating mode to adjust the engine operating state also includes: When the engine operating mode is determined to be the high-load operating mode, the exhaust gas recirculation module, the diesel supply module, and the methanol supply module are activated. Adjust the injection timing of the diesel supply module and the methanol supply module to control the engine to operate in a methanol partially premixed combustion mode; The second injection parameters and exhaust gas recirculation rate are adjusted according to the third preset output parameters; wherein, the third preset output parameters include engine load requirements, knock output feedback and knock pressure output feedback, and the second injection parameters include methanol primary injection ratio, methanol secondary injection ratio, methanol injection timing and diesel injection timing.

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