Dual-fuel engine, combustion system, and method for determining combustion system parameters

Abstract

This invention provides a dual-fuel engine, a combustion system, and a method for determining combustion system parameters, relating to the field of engine technology. The method for determining the combustion system parameters of a dual-fuel engine provided by the embodiments of this invention can determine the combustion system parameters of the dual-fuel engine. In a dual-fuel engine using these combustion system parameters, both the first injector and the second injector have the capability to deliver rated power. Therefore, when the first fuel is insufficient and the first injector cannot inject enough first fuel, the second fuel injected by the second injector can serve as the main fuel to ensure operation at rated power.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and more specifically, to a dual-fuel engine, a combustion system, and a method for determining combustion system parameters. Background Technology

[0002] To control greenhouse gas emissions, more explicit and stringent requirements have been put forward for the future energy structure, and the decarbonization or even zero-carbonization of fuels is an inevitable trend in future energy development.

[0003] The research, development, and utilization of alternative marine fuels (especially low-carbon and zero-carbon fuels) are of great significance. On the one hand, they can reduce dependence on traditional fossil fuels and avoid energy shortages; on the other hand, they can effectively utilize the physicochemical properties of clean fuels to reduce emissions of nitrogen oxides (NOx), particulate matter (PM), and greenhouse gases. Currently, common low-carbon marine fuels include liquefied natural gas (LNG), methanol, biodiesel, ammonia, and hydrogen. Compared with diesel, alternative marine fuels such as methanol have fundamentally different spray, ignition, and combustion characteristics, thus requiring specialized design of combustion system parameters and control of combustion organization. For large-bore marine diesel engines, due to the large cylinder space and low turbulence intensity, spark ignition can easily cause engine misfires and knocking. Therefore, the combustion organization often utilizes a pilot fuel ignition mode for alternative marine fuels.

[0004] Patent CN 114165329 A, entitled "Combustion Chamber Assembly, Method for Organizing Combustion, Computer-readable Medium, Internal Combustion Engine," discloses a combustion chamber assembly for igniting fuel and ignited fuel. The ignition fuel injector in the combustion chamber assembly is centrally offset and has a non-uniformly arranged injection structure. A combustion organization method is proposed based on this combustion chamber assembly, and both the combustion chamber assembly and the combustion organization method are applicable to methanol engines. However, using this combustion assembly and combustion organization method under medium-to-high load conditions after switching between methanol and diesel combustion modes, only methanol mode can be used for operation, making flexible switching between diesel and methanol modes under different loads impossible. In the absence of methanol fuel, ignition fuel can only maintain operation at 20% load, which is detrimental to ships responding to emergencies.

[0005] Therefore, for marine dual-fuel engines using alternative fuels, it is necessary to propose combustion systems that enable ships to cope with emergency situations, and methods for determining combustion system parameters. Summary of the Invention

[0006] The purpose of this invention is to provide a method for determining the combustion system parameters of a dual-fuel engine, which can improve the technical problem of difficulty in operating at high loads when fuels such as methanol are unavailable in the prior art.

[0007] The present invention also aims to provide a dual-fuel engine combustion system that can improve the technical problem of difficulty in operating at high loads when fuels such as methanol are unavailable in the prior art.

[0008] Another objective of this invention is to provide a dual-fuel engine that can improve the technical problem of difficulty in operating at high loads when fuels such as methanol are unavailable in the prior art.

[0009] Another objective of this invention is to provide a readable storage medium that can improve the technical problem of difficulty in operating at high loads when fuels such as methanol are unavailable in the prior art.

[0010] Embodiments of the present invention can be implemented in the following ways:

[0011] A method for determining combustion parameters of a dual-fuel engine, the method comprising:

[0012] Based on power requirements, characteristics of the first fuel, characteristics of the second fuel, requirements for the first fuel replacement rate, and the structure of the base engine, the installation positions and structural parameters of the first and second injectors are selected; wherein, the first injector is used to inject the first fuel, the second injector is used to inject the second fuel, and the second fuel is used to ignite the first fuel; the base engine uses the second fuel as its primary fuel.

[0013] A basic simulation model is obtained based on the structure of the basic engine, the installation location, the structural parameters, and the test data of the basic engine.

[0014] Using the aforementioned basic simulation model, the basic combustion system parameters are obtained through the required power calculation; wherein, the basic combustion system parameters include: first fuel system parameters, second fuel system parameters under the first fuel combustion mode, and combustion chamber structure parameters;

[0015] Based on the basic combustion system parameters and the basic simulation model, an optimized simulation model is constructed.

[0016] Numerical simulations are performed using the optimized simulation model, and the combustion macroscopic parameters are judged based on the simulation results to determine whether they meet the target. If the combustion macroscopic parameters do not meet the target, the basic combustion system parameters in the optimized simulation model are adjusted, and numerical simulations are performed using the adjusted optimized simulation model until the combustion macroscopic parameters meet the target. If the combustion macroscopic parameters meet the target, the combustion system parameters of the optimized simulation model are used as the combustion system parameters of the dual-fuel engine.

[0017] Optionally, the steps for selecting the installation location and structural parameters of the first and second injectors based on power requirements, first fuel characteristics, second fuel characteristics, first fuel replacement rate requirements, and the base engine include:

[0018] The ignition energy of the first fuel is obtained based on the first fuel.

[0019] The required mass of the first fuel is determined based on the first fuel substitution rate requirement.

[0020] Based on the power requirement, the ignition energy of the first fuel, the characteristics of the second fuel, and the required mass of the first fuel, determine the required mass of the second fuel in the main combustion mode and the required mass of the second fuel in the ignition mode;

[0021] The structural parameters of the first injector and the second injector are selected based on the required mass of the first fuel, the required mass of the second fuel in the main combustion mode, and the required mass of the second fuel in the ignition mode.

[0022] Optionally, the structure of the basic engine includes the cylinder head space and the initial profile of the piston's combustion chamber;

[0023] Based on power requirements, first fuel characteristics, second fuel characteristics, first fuel replacement rate requirements, and the base engine, the steps for selecting the installation location and structural parameters of the first and second injectors also include:

[0024] The installation positions of the first injector and the second injector are selected based on the cylinder head space and the initial profile of the piston's combustion chamber.

[0025] Optionally, the step of obtaining the basic simulation model based on the structure of the basic engine, the installation location, the structural parameters, and the test data of the basic engine includes:

[0026] An initial simulation model is built based on the structure of the basic engine, its installation location, and its structural parameters.

[0027] The initial simulation model is calibrated based on the test data of the basic engine to obtain the basic simulation model.

[0028] Optionally, the test data of the base engine includes the pressure curve and heat release rate curve obtained from the base engine test; the step of calibrating the initial simulation model based on the test data of the base engine includes:

[0029] The calculation model in the initial simulation model is adjusted until the deviation between the obtained simulated pressure curve and simulated heat release rate curve and the pressure curve and the heat release rate curve is within a preset range.

[0030] Optionally, the step of using the basic simulation model and calculating the basic combustion system parameters using the required power includes:

[0031] Using the aforementioned basic simulation model and through power simulation calculations, the required air mass and second fuel system parameters under different operating conditions in the second fuel main combustion mode are obtained; wherein, the second fuel system parameters in the second fuel main combustion mode are the first ignition fuel system parameters;

[0032] The basic combustion system parameters of the dual-fuel engine are obtained by using the basic simulation model and combining the required air mass and the parameters of the first and second fuel systems under different operating conditions.

[0033] Optionally, the method for determining the combustion system parameters of a dual-fuel engine further includes a step of verifying the combustion system parameters; the step of verifying the combustion system parameters includes:

[0034] The dual-fuel engine using the combustion system parameters was tested, and the results were used to determine whether the preset targets and stable combustion criteria were met. If the preset targets and stable combustion criteria were met, the verification was successful.

[0035] A dual-fuel engine combustion system, wherein the combustion system parameters of the dual-fuel engine combustion system are obtained according to the dual-fuel engine combustion system parameter determination method described above.

[0036] A dual-fuel engine, the dual-fuel engine comprising the dual-fuel engine combustion system described above.

[0037] A readable storage medium storing a computer program that is executed by a processor to implement the above-described method for determining parameters of a dual-fuel engine combustion system.

[0038] The beneficial effects of the dual-fuel engine, combustion system, combustion system parameter determination method, and readable storage medium provided by the embodiments of the present invention include:

[0039] This invention provides a method for determining combustion system parameters of a dual-fuel engine. The method includes selecting the installation positions and structural parameters of a first injector and a second injector based on power requirements, characteristics of a first fuel, characteristics of a second fuel, a first fuel substitution rate requirement, and the structure of a base engine. The first injector injects the first fuel, and the second injector injects the second fuel. The base engine uses an ignition material as its primary fuel. A basic simulation model is obtained based on the structure, installation position, structural parameters, and experimental data of the base engine. The basic combustion system parameters of the dual-fuel engine are calculated using the basic simulation model and the required power. These basic combustion system parameters include parameters of the first fuel system and parameters of the second fuel combustion system under the first fuel combustion mode. An optimized simulation model is constructed based on the basic combustion system parameters and the basic simulation model. Numerical simulation is performed using the optimized simulation model, and the simulation results are used to determine whether the macroscopic combustion parameters meet the target. If the macroscopic combustion parameters do not meet the target, the basic combustion system parameters in the optimized simulation model are adjusted, and numerical simulation is performed using the adjusted optimized simulation model until the macroscopic combustion parameters meet the target. If the macroscopic combustion parameters meet the target, the combustion system parameters of the optimized simulation model are used as the combustion system parameters of the dual-fuel engine. This method enables the determination of combustion system parameters for a dual-fuel engine. In a dual-fuel engine using these combustion system parameters, both the first and second injectors are capable of delivering rated power. Thus, when the first fuel is insufficient and the first injector cannot deliver enough first fuel, the second fuel delivered by the second injector can be used as the main fuel to ensure operation at rated power.

[0040] Embodiments of the present invention also provide a dual-fuel engine combustion system. The combustion system parameters of the dual-fuel engine combustion system are obtained by the above-described method for determining dual-fuel engine combustion system parameters. Therefore, it also has the beneficial effect that when the first fuel is insufficient and the first injector cannot inject enough first fuel, the second fuel injected by the second injector can be used as the main fuel to ensure operation at rated power.

[0041] Embodiments of the present invention also provide a dual-fuel engine, which includes the dual-fuel engine combustion system described above. Therefore, it also has the beneficial effect that when the first fuel is insufficient and the first injector cannot inject enough first fuel, the second fuel injected by the second injector can be used as the main fuel to ensure operation at rated power.

[0042] Embodiments of the present invention also provide a readable storage medium containing a computer program that performs the above-described method for determining the parameters of a dual-fuel engine combustion system. Therefore, it also has the beneficial effect of ensuring operation at rated power by using the second fuel injected by the second injector as the main fuel when the first fuel is insufficient and the first injector cannot inject enough first fuel. Attached Figure Description

[0043] The above-described features and advantages of the present invention will be better understood after reading the following detailed description of embodiments of the present disclosure in conjunction with the accompanying drawings. In the drawings, components are not necessarily drawn to scale, and components having similar related characteristics or features may have the same or similar reference numerals.

[0044] Figure 1 A schematic diagram of the structure of a dual-fuel engine combustion system according to one aspect of the present invention is shown;

[0045] Figure 2 A schematic diagram of the structure of a dual-fuel engine combustion system according to one aspect of the present invention is shown from another perspective.

[0046] Figure 3 A flowchart is shown of the execution steps S01 and S02 in a method for determining combustion system parameters of a dual-fuel engine according to an aspect of the present invention.

[0047] Figure 4 A flowchart illustrating the execution of steps S03 to S06 in a method for determining combustion system parameters of a dual-fuel engine according to one aspect of the present invention is shown.

[0048] Figure 5 A schematic diagram of a dual-fuel engine according to one aspect of the present invention is shown. Attached image description:

[0050] 10-Dual-fuel engine; 100-Dual-fuel engine combustion system; 110-Cylinder head; 111-Intake manifold; 112-Intake valve; 113-Exhaust manifold; 114-Exhaust valve; 115-Cylinder head fire shore; 116-First injector; 117-Second injector; 121-Combustion chamber; 122-Piston; 123-Dent; 124-Cylinder liner; 211-Crankshaft; 212-Connecting rod; 301-First fuel tank; 302-First fuel skid; 303-Valve assembly unit; 304-First fuel high-pressure pump; 305 - First fuel rail; 306 - First fuel pressure relief valve; 307 - First fuel rail pressure sensor; 401 - Second low-pressure fuel pump; 402 - Second fuel tank; 403 - Second high-pressure fuel pump; 404 - Second fuel rail; 405 - Second fuel supply pressure sensor; 406 - Second fuel pressure relief valve; 501 - Control unit; 502 - Intake pressure sensor; 503 - Knock sensor; 504 - Exhaust pressure sensor; 505 - Exhaust temperature sensor; 506 - Crankshaft sensor; 507 - Cam sensor. Detailed Implementation

[0051] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. It should be noted that the aspects described below with reference to the accompanying drawings and specific embodiments are merely exemplary and should not be construed as limiting the scope of protection of the present invention in any way.

[0052] In the description of this invention, it should be noted that if terms such as "upper," "lower," "inner," "outer," or "vertical" appear, the orientation or positional relationship indicated is based on the orientation or positional relationship shown in the accompanying drawings, or the orientation or positional relationship in which the product of this invention is usually placed when in use, and does not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0053] At the same time, it should be noted that the terms "first" and "second" are used only for distinguishing descriptions and should not be interpreted as indicating or implying relative importance.

[0054] In the description of this invention, it should also be noted that, unless otherwise explicitly specified or limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, an integral connection, or a detachable connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or a connection within two components, etc. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0055] Figure 1 This is a schematic diagram of the structure of a dual-fuel engine combustion system 100 provided in an embodiment of the present invention. Figure 2 A schematic diagram of the dual-fuel engine combustion system 100 provided in an embodiment of the present invention from another perspective. Figure 3 This is a flowchart of steps S01 and S02 in the method for determining the combustion system parameters of a dual-fuel engine provided in this embodiment. Figure 4 The flowchart illustrates steps S03 to S06 in the dual-fuel engine combustion system parameter determination method provided in this embodiment. Please refer to the attached flowchart. Figures 1-4 This embodiment provides a dual-fuel engine combustion system 100, which includes a cylinder head 110, a first injector 116, a second injector 117, and other components forming a combustion chamber 121. The cylinder head 110 has an intake manifold 111, an exhaust manifold, an intake valve 112, an exhaust valve 114, and a cylinder head fire seat 115. The intake valve 112 is located at the intake manifold 111 to allow gas to enter when the intake manifold 111 is opened by the intake valve 112. The exhaust valve 114 is located at the exhaust manifold 113 to allow gas to exit when the exhaust manifold 113 is opened by the exhaust valve 114. Specifically, in this embodiment, the cylinder head 110 has a four-valve structure, that is, it has two exhaust valves 114 and two intake valves 112. It can be understood that in some other embodiments, the structure of the cylinder head 110 can also be specifically configured according to requirements.

[0056] The first injector 116 and the second injector 117 are mounted on the cylinder head 110, and both the first injector 116 and the second injector 117 are eccentrically arranged. It is understood that the specific installation positions of the first injector 116 and the second injector 117 are not limited here. It is also understood that in some other embodiments, the arrangement positions of the first injector 116 and the second injector 117 can be set according to requirements.

[0057] The first injector 116 injects a first fuel into the combustion chamber 121, and the second injector 117 injects a second fuel into the combustion chamber 121. Therefore, the dual-fuel engine 10 is a dual direct injection engine. The second fuel is used to ignite the first fuel. In the mode where the first fuel is the primary fuel, the second fuel can be selected as the primary fuel. In this embodiment, the first fuel is methanol, and the second fuel is diesel. It is understood that in other embodiments, other fuels can also be selected as the first fuel, such as liquefied natural gas, biodiesel, and other marine alternative fuels. Similarly, other materials that can simultaneously perform ignition and primary combustion functions can also be selected as the second fuel.

[0058] Generally, the enclosed space formed by the cylinder head fire seat 115, the recess 123 on the top of the piston 122, and the cylinder liner 124 is the combustion chamber 121. Therefore, the other components of the combustion chamber 121 mentioned above may include the piston 122 and the cylinder liner 124.

[0059] The combustion system parameters in the dual-fuel engine combustion system 100 are obtained using the dual-fuel combustion system parameter determination method provided in this embodiment. The following explanation uses a methanol-fueled engine with methanol as the first fuel and diesel as the second fuel as an example. Understandably, in the following text, "methanol" refers to the first fuel, and "diesel" refers to the second fuel.

[0060] Specifically, the method for determining the combustion system parameters of this dual-fuel engine includes:

[0061] S01: Based on the power requirements, first fuel characteristics, second fuel characteristics, first fuel substitution rate requirements, and the structure of the base engine, select the installation positions and structural parameters of the first injector 116 and the second injector 117.

[0062] The basic engine is a structure in the prior art that uses a second fuel as the main fuel. Since the second fuel is diesel in this embodiment, the basic engine may also be referred to as a "diesel engine" in the following description. Specifically, step S01 includes:

[0063] S11: Obtain the ignition energy of the first fuel based on the characteristics of the first fuel.

[0064] S12: Determine the required mass of the first fuel based on the first fuel substitution rate requirement.

[0065] Specifically, the target for the first fuel substitution rate of the dual-fuel engine 10 is generally 95%, so the required mass of the first fuel can be calculated and determined based on the 95% first fuel substitution rate.

[0066] S13: Determine the required mass of the second fuel in the main combustion mode, the required mass of the second fuel in the ignition mode, and the required mass of the second fuel in the ignition mode based on the power requirements, the ignition energy of the first fuel, the characteristics of the second fuel, and the required mass of the first fuel.

[0067] S14: Select the structural parameters of the first injector 116 and the second injector 117 according to the required mass of the first fuel, the required mass of the second fuel in the main combustion mode, and the required mass of the second fuel in the ignition mode.

[0068] That is, the structural parameters of the first injector 116 and the second injector 117 selected in step S14 are such that the amount of the first fuel injected by the first injector 116 and the amount of the second fuel injected by the second injector 117 can meet the required quality requirements obtained in steps S11 and S13. Specifically, the structural parameters of the injectors include the number of holes, the hole diameter, the included angle, the extension height, and the length-to-diameter ratio.

[0069] S15: Select the installation positions of the first injector 116 and the second injector 117 based on the cylinder head space and the initial profile of the combustion chamber 121 of the piston 122.

[0070] The basic engine structure includes the cylinder head space and the initial profile of the combustion chamber 121 of the piston 122. With the basic engine structure determined, the mounting positions of the first injector 116 and the second injector 117 on the cylinder head 110 can be determined to achieve the installation of the first injector 116 and the second injector 117 within the limited cylinder head space.

[0071] S02: The basic simulation model is obtained based on the structure, installation location, structural parameters, and test parameters of the basic engine.

[0072] S21: Build an initial simulation model based on the structure, installation location, and structural parameters of the basic engine.

[0073] S22: Based on the test data of the basic engine, calibrate the initial simulation model to obtain the basic simulation model.

[0074] The test data of the basic engine are the pressure curve and heat release rate curve obtained from the diesel engine test. When executing step S22, the calculation model in the initial simulation model is adjusted until the deviation between the obtained simulated heat release rate curve and the simulated pressure curve and the heat release rate curve and pressure curve is within the preset range. The model obtained at this time is the basic simulation model.

[0075] In other words, the basic simulation model is a simulation model in which the deviation between the simulated pressure curve and the diesel engine pressure curve is within a preset range, and the deviation between the simulated heat release rate curve and the diesel engine heat release rate curve is within a preset range.

[0076] Optionally, the preset range can be set to 5%.

[0077] S03: Utilize the basic simulation model and calculate the basic combustion system parameters using the required power.

[0078] The basic combustion system parameters include first fuel system parameters, second fuel system parameters under the first fuel combustion mode, and combustion chamber structural parameters. Optionally, the first fuel system parameters may include first fuel injection orifice parameters, injection rate profile, injection mass, and direct injection timing. The second fuel system parameters under the first fuel combustion mode may include second fuel injection orifice parameters, injection rate profile, injection mass, and direct injection timing. Combustion chamber structural parameters may include compression ratio, clearance height, bore ratio, and apex angle.

[0079] Specifically, step S03 includes:

[0080] S31: Using the basic simulation model, and through the required power simulation calculation, the required air mass and second fuel system parameters under different operating conditions in the second fuel main combustion mode (i.e., when operating in diesel mode) are obtained.

[0081] Specifically, the parameters of the second fuel system under the second fuel main combustion mode are the parameters of the first ignition fuel system.

[0082] S32: Using the basic simulation model, and combining the required air mass and first ignition fuel system parameters obtained in step S31 under different operating conditions, the parameters of the first fuel combustion system, the parameters of the second fuel system under the first fuel combustion mode, and the combustion chamber structural parameters are calculated. Specifically, the parameters of the second fuel system under the first fuel combustion mode are the parameters of the second ignition fuel system. It should be noted that the first fuel combustion mode is the same as the ignition mode of the second fuel.

[0083] The parameters of the first fuel combustion system and the parameters of the second ignition fuel system are the same as the parameters of the basic combustion system.

[0084] Furthermore, after executing step S03, it can be determined whether the obtained basic combustion system parameters meet the replacement rate target and whether there is abnormal combustion. If the basic combustion system parameters meet the replacement rate target and there is no abnormal combustion, the next step can be continued; if the basic combustion system parameters do not meet the replacement rate target and there is no abnormal combustion, the basic combustion system parameters are adjusted.

[0085] S04: Based on the basic combustion system parameters and the basic simulation model, construct an optimized simulation model.

[0086] If the basic combustion system parameters are adjusted after step S03, the adjusted basic combustion system parameters are used to build the optimized simulation model.

[0087] S05: Use an optimized simulation model to perform numerical simulation, and determine whether the macroscopic combustion parameters meet the target based on the simulation results.

[0088] Numerical simulations are performed using an optimized simulation model. Specifically, the optimized simulation model calculates the distribution of the first and second fuels under different injection sequences and intervals in the first fuel mode of combustion chamber 121, as well as their coupled combustion process and the combustion process under the second fuel main combustion mode. Optionally, the injection sequence may include the first fuel entering the combustion chamber 121 before the second fuel, the pilot fuel entering the combustion chamber 121 before the first fuel, the second fuel entering the combustion chamber 121 in two parts before and after the first fuel, or the first fuel entering the combustion chamber 121 in two parts before and after the second fuel.

[0089] Combustion macroscopic parameters can be power and thermal efficiency. The simulated power and thermal efficiency are compared to determine whether the target is met. Optionally, the target can be set as the power and thermal efficiency of the diesel engine. In other words, if the simulated power and thermal efficiency are greater than or equal to the power and thermal efficiency of the diesel engine, the target is met. Conversely, if the simulated power and thermal efficiency are less than the power and thermal efficiency of the diesel engine, the target is not met.

[0090] If the objective is met, the combustion system parameters of the optimized simulation model can be used as the combustion system parameters of the dual-fuel engine combustion system 100. If the objective is not met, the process returns to step S04 to adjust the basic combustion system parameters used to build the optimized simulation model, resulting in a further optimized simulation model. Step S05 is then repeated until the objective is met. Specifically, when adjusting the basic combustion system parameters, the combustion chamber structure parameters and the nozzle structure parameters can be adjusted primarily.

[0091] S06: Verify the combustion system parameters.

[0092] After determining the combustion system parameters by performing step S05, these parameters can be verified through testing. The steps for verifying the combustion system parameters include:

[0093] S61: Test the dual-fuel engine 10 using the combustion system parameters.

[0094] S62: Determine whether the preset target and stable combustion criteria are met based on the test results.

[0095] Specifically, preset targets may include power targets, substitution rate targets, and emission optimization targets. Combustion stability criterion (COV) IMEP ≤X, COV Pmax ≤Y) mainly verifies whether combustion instability occurs during the test. Combustion instability can be judged by the cyclic changes in engine exhaust temperature, average indicated pressure, and maximum in-cylinder pressure.

[0096] If the preset target and stable combustion criteria are met, it means that the combustion system parameters have passed the verification. If the preset target and stable combustion criteria are not met, the performance parameters of the dual-fuel engine 10 can be adjusted. If the preset target and stable combustion criteria are still not met after multiple adjustments, it means that the combustion system parameters have not passed the verification. At this time, you can return to step S04 and adjust the basic combustion system parameters for building the optimized simulation model.

[0097] Figure 5 A schematic diagram of the structure of the dual-fuel engine 10 provided in this embodiment is shown. Please refer to... Figure 5This embodiment also provides a dual-fuel engine 10, which employs the aforementioned dual-fuel engine combustion system 100. The dual-fuel engine 10 also includes a crankshaft 125 and a connecting rod 212. The piston 122 is connected to a drive via the connecting rod 212, thereby realizing power transmission between the piston 122 and the crankshaft 125.

[0098] Furthermore, the dual-fuel engine 10 also includes a first fuel supply system, a second fuel supply system, and a control system. The first fuel supply system includes a first fuel tank 301, a first fuel skid 302, a valve unit 303 (FVT), a first high-pressure fuel pump 304, a first fuel rail 305, and a first fuel pressure relief valve 306. The second fuel supply system includes a second low-pressure fuel pump 401, a second fuel tank 402, a second high-pressure fuel pump 403, a second fuel rail 404, and a second fuel pressure relief valve 406. The control system includes a control unit 501, a crankshaft sensor 506, a camshaft sensor, an intake pressure sensor 502, and a knock sensor 503; the first fuel rail pressure sensor 307 and the first fuel pressure relief valve 306 are both electrically connected to the control unit 501, and the second fuel supply pressure sensor 405 and the second fuel pressure relief valve 406 are also electrically connected to the control unit 501.

[0099] Furthermore, the dual-fuel engine 10 can be used in dual-fuel ships; in other words, the dual-fuel engine 10 can be a marine engine.

[0100] Embodiments of the present invention also provide a readable storage medium. Based on this understanding, the present invention can implement all or part of the processes in the methods of the above embodiments, or it can be implemented by a computer program instructing related hardware. The computer program resides in the readable storage medium, and when executed by a processor, it can implement at least some steps in the above-described method for determining the parameters of a dual-fuel engine combustion system. The computer program includes computer program code, which can be in the form of source code, object code, executable files, or certain intermediate forms. The computer-readable medium can include: any entity or device capable of carrying computer program code, recording media, USB flash drives, portable hard drives, magnetic disks, optical disks, computer memory, read-only memory (ROM), random access memory (RAM), electrical carrier signals, telecommunication signals, and software distribution media, etc. It should be noted that the content included in the computer-readable medium can be appropriately added or removed according to the requirements of legislation and patent practice in the jurisdiction. For example, in some jurisdictions, according to legislation and patent practice, the computer-readable medium does not include electrical carrier signals and telecommunication signals.

[0101] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for determining combustion system parameters of a dual-fuel engine, characterized in that, The method for determining the parameters of the dual-fuel engine combustion system includes: Based on power requirements, characteristics of the first fuel, characteristics of the second fuel, requirements for the first fuel replacement rate, and the structure of the base engine, the installation positions and structural parameters of the first and second injectors are selected; wherein, the first injector is used to inject the first fuel, the second injector is used to inject the second fuel, and the second fuel is used to ignite the first fuel; the base engine uses the second fuel as its primary fuel. A basic simulation model is obtained based on the structure of the basic engine, the installation location, the structural parameters, and the test data of the basic engine. Using the aforementioned basic simulation model, the basic combustion system parameters are obtained through the required power calculation; wherein, the basic combustion system parameters include: first fuel system parameters, second fuel system parameters under the first fuel combustion mode, and combustion chamber structure parameters; Based on the basic combustion system parameters and the basic simulation model, an optimized simulation model is constructed. Numerical simulations are performed using the optimized simulation model, and the combustion macroscopic parameters are judged based on the simulation results to determine whether they meet the target. If the combustion macroscopic parameters do not meet the target, the basic combustion system parameters in the optimized simulation model are adjusted, and numerical simulations are performed using the adjusted optimized simulation model until the combustion macroscopic parameters meet the target. If the combustion macroscopic parameters meet the target, the combustion system parameters of the optimized simulation model are used as the combustion system parameters of the dual-fuel engine. The steps of selecting the installation positions and structural parameters of the first and second injectors based on power requirements, first fuel characteristics, second fuel characteristics, first fuel substitution rate requirements, and the structure of the base engine include: The ignition energy of the first fuel is obtained based on the characteristics of the first fuel. The required mass of the first fuel is determined based on the first fuel substitution rate requirement. Based on the power requirement, the ignition energy of the first fuel, the characteristics of the second fuel, and the required mass of the first fuel, determine the required mass of the second fuel in the main combustion mode and the required mass of the second fuel in the ignition mode; The structural parameters of the first injector and the second injector are selected based on the required mass of the first fuel, the required mass of the second fuel in the main combustion mode, and the required mass of the second fuel in the ignition mode. The numerical simulation using the optimized simulation model includes: using the optimized simulation model to calculate the distribution of the first fuel and the second fuel under different injection sequences and injection intervals in the first fuel combustion mode of the combustion chamber, as well as the coupled combustion process of the two and the combustion process under the second fuel main combustion mode; The macroscopic combustion parameters include power and thermal efficiency. When the simulated power and thermal efficiency are greater than or equal to the power and thermal efficiency of the base engine, the target is deemed to be met; if the simulated power and thermal efficiency are less than the power and thermal efficiency of the base engine, the target is deemed not to be met.

2. The method for determining combustion system parameters of a dual-fuel engine according to claim 1, characterized in that, The structure of the basic engine includes the cylinder head space and the initial profile of the piston's combustion chamber; Based on power requirements, first fuel characteristics, second fuel characteristics, first fuel replacement rate requirements, and the structure of the base engine, the steps for selecting the installation locations and structural parameters of the first and second injectors also include: The installation positions of the first injector and the second injector are selected based on the cylinder head space and the initial profile of the piston's combustion chamber.

3. The method for determining the parameters of a dual-fuel engine combustion system according to claim 1, characterized in that, The steps for obtaining the basic simulation model based on the structure of the basic engine, the installation location, the structural parameters, and the test data of the basic engine include: An initial simulation model is built based on the structure of the basic engine, its installation location, and its structural parameters. The initial simulation model is calibrated based on the test data of the basic engine to obtain the basic simulation model.

4. The method for determining combustion system parameters of a dual-fuel engine according to claim 3, characterized in that, The test data of the base engine includes the pressure curve and heat release rate curve obtained from the test of the base engine; The steps for calibrating the initial simulation model based on the test data of the base engine include: The calculation model in the initial simulation model is adjusted until the deviation between the obtained simulated pressure curve and simulated heat release rate curve and the experimentally obtained pressure curve and heat release rate curve is within a preset range.

5. The method for determining the parameters of a dual-fuel engine combustion system according to claim 1, characterized in that, The steps for obtaining the basic combustion system parameters using the aforementioned basic simulation model and the required power calculation include: Using the aforementioned basic simulation model and through power simulation calculations, the required air mass and second fuel system parameters under different operating conditions in the second fuel main combustion mode are obtained; wherein, the second fuel system parameters in the second fuel main combustion mode are the first ignition fuel system parameters; Using the aforementioned basic simulation model, and combining the required air mass and the parameters of the first ignition fuel system under different operating conditions, the basic combustion system parameters of the dual-fuel engine are obtained through simulation calculation.

6. The method for determining combustion system parameters of a dual-fuel engine according to claim 1, characterized in that, The method for determining the combustion system parameters of a dual-fuel engine further includes a step of verifying the combustion system parameters; the step of verifying the combustion system parameters includes: The dual-fuel engine using the combustion system parameters was tested, and the results were used to determine whether the preset targets and stable combustion criteria were met. If the preset targets and stable combustion criteria were met, the verification was successful.

7. A dual-fuel engine combustion system, characterized in that, The combustion system parameters of the dual-fuel engine combustion system are obtained according to the dual-fuel engine combustion system parameter determination method as described in any one of claims 1-6.

8. A dual-fuel engine, characterized in that, The dual-fuel engine includes the dual-fuel engine combustion system as described in claim 7.

9. A readable storage medium, characterized in that, The readable storage medium stores a computer program that is executed by a processor to implement the method for determining the parameters of a dual-fuel engine combustion system as described in any one of claims 1-6.

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