Internal and external cooperative control method for pollutant emission machine of ammonia-related engine

Abstract

The invention discloses an internal and external cooperative control method for an ammonia-related engine pollutant emission machine. A strategy 1 is adopted when ANMR is smaller than or equal to 1, and a strategy 2 is adopted if ANMR is smaller than or equal to 1; according to the first strategy, when the NOx concentration of a preceding-stage SCR outlet in an ammonia-related engine aftertreatment catalyst module is smaller than or equal to a threshold value 1, the urea injection amount is controlled to be zero, and otherwise, the urea injection amount is corrected; strategy 2: S1: on the premise that the absolute value of the fuel economy loss is less than or equal to a threshold value 2, optimizing combustion in an ammonia-related engine cylinder, after optimization, turning to the strategy 1 when ANMR is less than or equal to 1, and otherwise, turning to the strategy S2; s2, when the NH3 concentration of an outlet of a post-treatment catalyst module is smaller than a threshold value 3, cooperative control is finished, and otherwise, S3 is executed; s3, if the load rate of the ammonia-related engine is larger than or equal to a threshold value 4, the step S1 is executed, and otherwise, the step S4 is executed; s4, if the ammonia energy replacement rate is larger than or equal to the threshold value 5, the step S1 is executed, otherwise, the step S5 is executed; and S5, when the NH3 concentration of an outlet of the post-treatment catalyst module is smaller than or equal to a threshold value 3, the urea injection amount is controlled to be zero, and otherwise, the post-treatment catalyst module is reconfigured. According to the invention, the economical efficiency is basically unchanged after the engine is additionally provided with the post-processing system.

Description

Technical Field

[0001] The present invention belongs to the field of coordinated in-cylinder optimization and control strategies for advanced after-treatment of ammonia-related engines. More specifically, it relates to a method for coordinated in- and out-of-engine control of pollutant emissions from ammonia-related engines based on active control of the original emission ANMR (Ammonia-to-Nitrogen Oxides Molar Ratio). Background Art

[0002] Internal combustion engines, especially heavy-duty internal combustion engines, will remain important prime movers for industries such as road transportation, construction machinery, and shipping for the foreseeable future due to their excellent fuel economy, strong power, and high reliability. Low-carbon and zero-carbon internal combustion engine fuels are becoming increasingly imperative. Ammonia, as a renewable energy carrier, can be a clean alternative fuel for internal combustion engines. However, due to ammonia's inherent ignition resistance and slow combustion rate, a highly reactive fuel is required for ignition. Diesel is a good and low-cost alternative.

[0003] A traditional engine aftertreatment system primarily consists of a catalyst module and a urea injection module. The catalyst module comprises a DOC (diesel oxidation catalyst), a DPF (particulate filter), an SCR (selective catalytic reduction device), and an ASC (ammonia slip catalyst). Unlike traditional engines, ammonia-based engines contain ammonia in both fuel and raw engine emissions, resulting in both NH3 and NOx. NOx, the primary engine emission, is currently primarily treated by injecting a urea-water solution into the aftertreatment system. The urea-water solution undergoes thermal decomposition to produce NH3, which reacts with NOx in the SCR module to produce harmless N2 and H2O. Traditional aftertreatment systems primarily rely on NOx sensors placed at the aftertreatment inlet and outlet. These sensors measure NOx concentrations at the system inlet and outlet, using this information to calculate the urea injection amount and correction factor. However, for ammonia-related engines, since gaseous NH3 exists in their original emissions and the concentration of gaseous NH3 in the exhaust gas changes with the engine speed and load, there is currently a lack of suitable miniaturized NH3 sensors to directly test the NH3 concentration in the exhaust gas to provide a basis for the injection of urea aqueous solution in the after-treatment system.

[0004] In summary, in order to ensure that ammonia-related engines meet regulatory emissions requirements while minimizing the reduction in fuel economy caused by the installation of an after-treatment system, it is necessary to start from the in-cylinder combustion process and combine the after-treatment system control strategy to synergistically resolve the contradiction between NH3 in the original emissions of ammonia-related engines and the after-treatment system control strategy. Summary of the Invention

[0005] The purpose of the present invention is to overcome the deficiencies in the prior art and propose a method for coordinated internal and external control of pollutant emissions from ammonia-related engines based on active control of original emissions ANMR, to ensure that after the engine is equipped with an after-treatment system, its emissions meet regulatory requirements while its economy remains basically unchanged.

[0006] The objectives of the present invention are achieved through the following technical solutions.

[0007] A method for coordinated internal and external control of pollutant emissions from an ammonia-related engine, comprising:

[0008] Real-time monitoring of pollutant concentrations and components in the raw exhaust of ammonia-related engines across the entire operating range to obtain the ammonia-nitrogen molar ratio (ANMR) of the raw exhaust of ammonia-related engines. If ANMR is ≤ 1, strategy 1 is used for coordinated control; if ANMR is > 1, strategy 2 is used for coordinated control.

[0009] Strategy 1: Real-time monitoring of the NOx concentration at the outlet of the pre-stage SCR in the after-treatment catalyst module of an ammonia engine. If the NOx concentration at the outlet of the pre-stage SCR is less than or equal to a threshold of 1, no additional urea injection is required into the after-treatment catalyst module, and the urea injection rate is controlled to zero. If the NOx concentration at the outlet of the pre-stage SCR is greater than the threshold of 1, the urea injection rate into the after-treatment catalyst module is adjusted.

[0010] Strategy 2:

[0011] Step S1: Under the premise that the absolute value of the fuel economy loss is not higher than a threshold value 2, the combustion in the cylinder of the ammonia-related engine is optimized by adjusting the fuel injection strategy and the fuel energy distribution strategy of the ammonia-related engine. After the optimization, the concentration and composition of pollutants in the original exhaust gas of the ammonia-related engine are monitored in real time within the full operating range to obtain the ammonia-nitrogen molar ratio ANMR of the original exhaust gas of the ammonia-related engine at that time; if the optimized ANMR is ≤ 1, the cycle is switched to strategy 1 for further control; if the optimized ANMR is still greater than 1, the process is switched to step S2;

[0012] Step S2: Real-time monitoring of the NH3 concentration at the outlet of the post-treatment catalyst module. If the NH3 concentration at the outlet of the post-treatment catalyst module is less than a threshold value of 3, no additional control is required and the optimized coordinated control ends. If the NH3 concentration at the outlet of the post-treatment catalyst module is greater than or equal to the threshold value of 3, the process proceeds to step S3.

[0013] Step S3, determining whether the current ammonia engine load rate is greater than or equal to a threshold value 4, if so, looping back to step S1, if not, looping back to step S4;

[0014] Step S4, determining whether the ammonia energy replacement rate is greater than or equal to a threshold value of 5. If the ammonia energy replacement rate is greater than or equal to the threshold value of 5, the process loops back to step S1; if the ammonia energy replacement rate is less than the threshold value of 5, the process loops back to step S5.

[0015] Step S5, determining whether the NH3 concentration at the outlet of the post-treatment catalyst module is less than or equal to threshold 3. If the judgment result is yes, no additional urea injection is required into the post-treatment catalyst module, and the urea injection amount is controlled to zero. If the judgment result is no, reconfigure the current post-treatment catalyst module.

[0016] Furthermore, a raw emission concentration monitoring window is set on the exhaust pipe between the turbocharger and the inlet of the post-treatment catalyst module of the ammonia engine. The pollutant concentration and composition in the raw exhaust gas of the ammonia engine are monitored in real time in the raw emission concentration monitoring window under the full operating range. Based on the concentrations of NOx and NH3, the ANMR of the raw emissions of the ammonia engine is calculated according to the following formula:

[0017] ,

[0018] ,

[0019] ,

[0020] Where ANMR is the ammonia nitrogen molar ratio, is the number of moles of NH3, is the number of moles of NOx, is the volume concentration of NH3, is the volume concentration of NOx, It is the engine exhaust volume flow converted to standard conditions according to the ideal gas equation.

[0021] Furthermore, the method of the present invention is applicable to an ammonia-diesel dual-fuel engine, a pure ammonia engine or an ammonia-hydrogen dual-fuel engine.

[0022] Compared with the prior art, the technical solution of the present invention has the following beneficial effects:

[0023] The present invention includes a complete pollutant emission optimization strategy and a pollutant emission online control strategy for an ammonia-related engine, namely, Strategy 1, Strategy 2 and the associated input conditions and output optimization directions.

[0024] Since the theoretical ANR required for NOx reduction in the after-treatment system is 1, for ammonia-related engines, since the exhaust gas naturally contains ammonia and NOx, a parameter is defined in the present invention, namely ANMR. This parameter is a key parameter for optimizing pollutants in ammonia-related engines and controlling the urea injection amount in the after-treatment system. It is also one of the core parameters of the control strategy described in the present invention. By judging the size of ANMR, it is determined whether strategy 1 or strategy 2 is used for coordinated control.

[0025] Strategy 1 is to control urea in the after-treatment system based on the NOx concentration at the outlet of the front-stage SCR of the after-treatment catalyst module in the after-treatment system.

[0026] One of the possible results of the optimization of Strategy 2 is the re-optimization of the ASC for after-treatment, which also points out the direction of optimization required when the after-treatment system used in the current test cannot meet the requirements of exhaust gas treatment of ammonia-related engines.

[0027] The current ammonia engine load rate ≥ threshold 4 and the ammonia energy substitution rate ≥ threshold 5 in strategy 2 are the boundary conditions for optimizing the performance and pollutant emissions of the ammonia dual-fuel engine within the full load range, thereby maximizing the ammonia substitution rate within the full load range of the ammonia engine while effectively controlling the pollutant emission level, allowing the engine to operate efficiently and cleanly.

[0028] Figures in the specification

[0029] Figure 1 This is a flow chart of the method for coordinated control of pollutant emissions from ammonia engines according to the present invention.

[0030] Figure 2 This is a schematic diagram of an ammonia-diesel dual-fuel engine with an after-treatment system according to an embodiment of the present invention.

[0031] Figure 3 Schematic diagram of the post-treatment catalyst module in an embodiment of the present invention.

[0032] Figure 1: 1- ammonia cylinder, 2- ammonia pressure control device, 3- pressure stabilizing tank, 4- ammonia rail, 5- ammonia injector, 6- diesel injector, 7- engine, 8- fuel pump, 9- high-pressure fuel rail, 10- control computer, 11- electronic control module, 12- ammonia supply pipeline, 13- fuel supply pipeline, 14- post-intercooler pressure sensor, 15- post-intercooler temperature sensor, 16- intake pipe, 17- intercooler, 18- turbocharger, 19- post-turbine temperature / pressure sensor, 20- post-treatment system inlet temperature / pressure sensor, 21- front-stage SCR outlet temperature / pressure sensor, 22- front-stage SCR outlet NOx concentration sensor, 23- DPF outlet temperature / pressure sensor, 24- After-treatment outlet NOx concentration sensor, 25-After-treatment outlet temperature / pressure sensor, 26-Pre-SCR outlet NH3 concentration monitoring window, 27-After-treatment outlet NH3 concentration monitoring window, 28-Urea nozzle, 29-Original emission concentration monitoring window, 30-Exhaust pipe, 31-After-treatment catalyst module. DETAILED DESCRIPTION

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention are described in detail below with reference to the accompanying drawings, so that the above-mentioned and other objects, features and advantages of the present invention will become clearer. The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0034] Since there is currently no coordinated control strategy for the coordinated in-cylinder combustion and post-treatment system control of ammonia-related dual-fuel engine exhaust emissions, the present invention proposes a method for coordinated in- and out-of-engine control of ammonia-related engine pollutant emissions, such as Figure 1 As shown, including the following:

[0035] Real-time monitoring of pollutant concentrations and components in the original exhaust gas of the ammonia-related engine within the full operating range is performed to obtain the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine. When ANMR=1, it is considered that the NH3 in the original emission can completely react with the NOx in the original emission. Therefore, under a reasonable catalyst configuration, the concentrations of NOx and NH3 at the outlet of the post-treatment catalyst module can be reduced to below the regulatory requirements. When ANMR<1, it is necessary to determine whether urea needs to be injected into the post-treatment catalyst module to convert NOx based on the NOx concentration at the outlet of the post-treatment catalyst module. Therefore, when ANMR≤1, it is mainly necessary to control the post-treatment system. The essence of the problem is the same. Therefore, when ANMR≤1, the following strategy 1 is adopted for coordinated control. If ANMR>1, the following strategy 2 is adopted for coordinated control.

[0036] Preferably, a raw emission concentration monitoring window can be set on the exhaust pipe between the turbocharger and the inlet of the post-treatment catalyst module of the ammonia engine. The pollutant concentration and composition in the raw exhaust gas of the ammonia engine under the full operating range are monitored in real time in the raw emission concentration monitoring window. According to the concentrations of NOx and NH3, the ANMR of the raw emission of the ammonia engine is calculated according to the following formula:

[0037] (1),

[0038] (2),

[0039] (3),

[0040] Where, is the number of moles of NH3, is the number of moles of NOx, is the volume concentration of NH3, is the volume concentration of NOx, The ANMR is the volumetric flow rate of engine exhaust converted to standard conditions based on the ideal gas equation. Since the theoretical ANR required for NOx reduction in the aftertreatment system is 1, for ammonia-based engines, since exhaust naturally contains ammonia and NOx, a parameter, ANMR, is defined in this invention. This parameter is a key parameter for pollutant optimization in ammonia-based engines and for controlling urea injection in aftertreatment systems. It is also one of the core parameters of the control strategy described in this invention.

[0041] Strategy 1: Monitor the NOx concentration at the outlet of the front-stage SCR in the after-treatment catalyst module of the ammonia engine in real time, and determine whether the urea injection amount of the after-treatment catalyst module needs to be corrected based on this concentration. If the NOx concentration at the outlet of the front-stage SCR is ≤ threshold 1 (such as 30ppm), no additional urea injection is required in the after-treatment catalyst module, and the urea injection amount is controlled to zero. If the NOx concentration at the outlet of the front-stage SCR is greater than threshold 1, the urea injection amount of the after-treatment catalyst module needs to be corrected. The correction method is to correct the urea injection amount based on the MAP (data table) with an ammonia-nitrogen molar ratio of 1, where the nitrogen concentration is derived from the real-time measured NOx concentration at the outlet of the front-stage SCR in the after-treatment catalyst module.

[0042] Strategy 2:

[0043] In step S1, it is necessary to optimize the combustion in the cylinder of the ammonia engine by adjusting the fuel injection strategy and fuel energy distribution strategy of the ammonia engine, under the premise that the absolute value of the fuel economy loss is not higher than the threshold value 2 (such as 3%), such as optimizing the pollutant emission level and concentration ratio of the ammonia engine. After the optimization, the pollutant concentration and composition in the original exhaust gas of the ammonia engine are monitored in real time within the full operating range. The ammonia nitrogen molar ratio ANMR of the original emission of the ammonia engine at this time can be calculated according to the above formulas (1)-(3); if the optimized ANMR is ≤1, the cycle goes to strategy 1 for further control; if the optimized ANMR is still greater than 1, the process goes to step S2.

[0044] Step S2: monitor the NH3 concentration at the outlet of the post-treatment catalyst module in real time. If the NH3 concentration at the outlet of the post-treatment catalyst module is less than a threshold value of 3 (such as 10 ppm), no additional control is required and the optimized collaborative control ends. If the NH3 concentration at the outlet of the post-treatment catalyst module is greater than or equal to the threshold value of 3, proceed to step S3.

[0045] Step S3, determine whether the current ammonia-related engine load rate is greater than or equal to a threshold value 4 (such as 25%). If so, loop back to step S1; if not, loop back to step S4.

[0046] Step S4, determine whether the ammonia energy substitution rate (derived from the fuel energy allocation strategy of the ammonia engine) is greater than or equal to a threshold value of 5. If the ammonia energy substitution rate is greater than or equal to the threshold value 5 (such as 40%), the loop goes to step S1; if the ammonia energy substitution rate is less than the threshold value 5, the loop goes to step S5.

[0047] Step S5, judging whether the NH3 concentration at the outlet of the after-treatment catalyst module is less than or equal to a threshold value 3 (such as 10 ppm, etc.). If the judgment result is yes, then no additional urea needs to be injected into the after-treatment catalyst module, and the urea injection amount is controlled to zero at this time. If the judgment result is no, then it indicates that the current after-treatment catalyst module structure cannot fully process the original NH3 emissions of the ammonia-related engine, and the current after-treatment catalyst module needs to be reconfigured, specifically by re-optimizing the ASC unit of the after-treatment catalyst module.

[0048] The above-described method is applicable not only to ammonia-diesel dual-fuel engines but also to extreme cases, such as pure ammonia engines with zero diesel, and to ammonia-hydrogen dual-fuel engines and other ammonia-related engines. Furthermore, with the exception of threshold 3 (10 ppm), the specific values ​​of the remaining thresholds may vary depending on the ammonia engine model.

[0049] Example:

[0050] In this embodiment, the ammonia-related engine is Figure 2 The test bench hardware system for the ammonia-diesel dual-fuel engine shown in the figure primarily consists of an ammonia cylinder 1, an ammonia pressure control device 2, a surge tank 3, an ammonia rail 4, an ammonia injector 5, a diesel injector 6, an engine 7, a fuel pump 8, a high-pressure fuel rail 9, a control computer 10, an electronic control module 11, and an aftertreatment system. The electronic control module 11 can be an ECU. The dashed lines in the figure represent the electronic control circuitry.

[0051] The fuel supply system of the ammonia-diesel dual-fuel engine includes a diesel supply system and an ammonia supply system. Diesel fuel is delivered to a high-pressure fuel rail 9 via the diesel supply system's fuel pump 8. Diesel fuel is then injected into each cylinder of the engine 7 via a fuel supply line 13 through multiple diesel injectors 6. The ammonia supply system is a low-pressure ammonia injection system. Ammonia is delivered from an ammonia cylinder 1 to an ammonia pressure control device 2. A surge tank 3 maintains the pressure of the ammonia supply rail 4, where it is then injected into the intake manifold of each cylinder of the engine 7 via an ammonia supply line 12 through multiple ammonia injectors 5. Furthermore, the exhaust port of the engine 7 is connected to the turbine inlet of the turbocharger 18 via an exhaust pipe 30. The intake port of the engine 7 is connected to the outlet of the intercooler 17 via an intake pipe 16. The inlet of the intercooler 17 is connected to the outlet of the compressor of the turbocharger 18 via a pipeline. Fresh air is supplied to the compressor inlet. The intake pipe 16 is also equipped with an intercooler pressure sensor 14 and an intercooler temperature sensor 15.

[0052] The aftertreatment system of the ammonia-diesel dual-fuel engine is arranged after the turbocharger 18. After the engine exhaust is discharged from the exhaust pipe 30, it enters the aftertreatment system after the turbocharger 18. The aftertreatment system mainly includes a post-turbine temperature / pressure sensor 19, an aftertreatment system inlet temperature / pressure sensor 20, a pre-SCR outlet temperature / pressure sensor 21, a pre-SCR outlet NOx concentration sensor 22, a DPF outlet temperature / pressure sensor 23, an aftertreatment outlet NOx concentration sensor 24, an aftertreatment outlet temperature / pressure sensor 25, a pre-SCR outlet NH3 concentration monitoring window 26, an aftertreatment outlet NH3 concentration monitoring window 27, a urea nozzle 28, a raw emission concentration monitoring window 29, and an aftertreatment catalyst module 31.

[0053] like Figure 3 As shown, the post-treatment catalyst module 31 includes a first SCR unit 32, a second SCR unit 33, a DOC unit 34, a DPF unit 35, a third SCR unit 36, and an ASC unit 37, which are arranged in sequence from the inlet to the outlet. The first SCR unit 32 and the second SCR unit 33 can be collectively referred to as the front-stage SCR, and the third SCR unit 36 ​​can be referred to as the rear-stage SCR. The after-turbine temperature / pressure sensor 19 and the original emission concentration monitoring window 29 are arranged on the exhaust pipe between the outlet of the turbocharger 18 and the inlet of the after-treatment catalyst module 31, the after-treatment system inlet temperature / pressure sensor 20 is arranged at the inlet of the first SCR unit 32, the front-stage SCR outlet temperature / pressure sensor 21 is arranged at the outlet of the second SCR unit 33, the front-stage SCR outlet NOx concentration sensor 22, the DPF outlet temperature / pressure sensor 23, the front-stage SCR outlet NH3 concentration monitoring window 26, and the urea nozzle 28 are arranged between the outlet of the DPF unit 35 and the inlet of the third SCR unit 36, the after-treatment outlet NOx concentration sensor 24 is arranged at the outlet of the ASC unit 37, and the after-treatment outlet temperature / pressure sensor 25 and the after-treatment outlet NH3 concentration monitoring window 27 are arranged on the exhaust pipe connected to the outlet of the after-treatment catalyst module 31.

[0054] In the present invention, the test bench system is arranged with three NH3 concentration measurement points, namely the NH3 concentration monitoring window 26 at the front-stage SCR outlet, the NH3 concentration monitoring window 27 at the after-treatment outlet, and the original emission concentration monitoring window 29, and two NOx concentration sensors are arranged, namely the NOx concentration sensor 22 at the front-stage SCR outlet and the NOx concentration sensor 24 at the after-treatment outlet, which are used to monitor the NOx concentration at the front-stage SCR outlet and the NOx concentration in the after-treatment system. At the same time, the NOx concentration at the front-stage SCR outlet is also the basis for judging the urea control of the after-treatment system in Strategy 1.

[0055] The pollutant emission coordinated control process inside and outside the ammonia-diesel dual-fuel engine in this embodiment is as follows:

[0056] In the raw exhaust concentration monitoring window 29, the pollutant concentrations and components in the raw exhaust of the ammonia-diesel engine are monitored in real time across the entire operating range. Based on the NOx and NH3 concentrations, the ANMR of the raw exhaust of the ammonia-diesel engine is calculated according to equations (1)-(3). If ANMR ≤ 1, coordinated control is implemented using Strategy 1, described below. If ANMR > 1, coordinated control is implemented using Strategy 2, described below.

[0057] Strategy 1: Use the pre-SCR outlet NOx concentration sensor 22 to monitor the NOx concentration at the pre-SCR outlet of the ammonia-diesel engine's after-treatment catalyst module in real time. This concentration is used to determine whether the urea injection rate at the after-treatment catalyst module needs to be adjusted. When ANMR ≤ 1, the after-treatment system may face two issues, each requiring separate treatment. While allowing for a certain engineering margin based on current regulations, threshold 1 is set at 30 ppm. When the pre-SCR outlet NOx concentration is ≤ 30 ppm, it indicates it is below the regulatory limit. In this case, no additional urea injection is required into the after-treatment catalyst module; the urea injection rate is controlled to zero. When the pre-SCR outlet NOx concentration exceeds 30 ppm, the urea injection rate needs to be adjusted. This adjustment is based on a MAP (map) with an ammonia-nitrogen molar ratio of 1. The nitrogen concentration is derived from the pre-SCR outlet NOx concentration at the after-treatment catalyst module, as measured in real time by the pre-SCR outlet NOx concentration sensor 22.

[0058] Strategy 2:

[0059] In step S1, it is necessary to optimize the in-cylinder combustion of the ammonia-diesel dual-fuel engine by adjusting the fuel injection strategy and fuel energy distribution strategy, provided that the absolute value of the fuel economy loss is not higher than 3% (threshold 2). After optimization, the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine is calculated according to the above formulas (1)-(3). If the optimized ANMR is ≤1, the cycle returns to strategy 1 for further control. If the optimized ANMR is still greater than 1, the cycle returns to step S2.

[0060] Step S2: Real-time monitoring of the NH3 concentration at the outlet of the post-treatment catalyst module in the post-treatment outlet NH3 concentration monitoring window 27. If the NH3 concentration at the outlet of the post-treatment catalyst module is less than 10 ppm (threshold 3), no additional control is required and the optimized coordinated control ends. If the NH3 concentration at the outlet of the post-treatment catalyst module is greater than or equal to 10 ppm (threshold 3), the process proceeds to step S3.

[0061] Step S3, determining whether the current load rate of the ammonia-diesel dual-fuel engine is greater than or equal to 25% (threshold 4); if so, looping back to step S1; if not, looping back to step S4;

[0062] Step S4: Determine whether the ammonia energy substitution rate (derived from the fuel energy allocation strategy of the ammonia-diesel dual-fuel engine) is greater than or equal to 40% (threshold 5). If the ammonia energy substitution rate is ≥40%, the process loops back to step S1. If the ammonia energy substitution rate is less than 40%, the process loops back to step S5.

[0063] Step S5, judging whether the NH3 concentration at the outlet of the after-treatment catalyst module monitored in real time at the after-treatment outlet NH3 concentration monitoring window 27 is less than or equal to 10ppm (threshold 3); if the judgment result is yes, then no additional urea needs to be injected into the after-treatment catalyst module, and the urea injection amount is controlled to be zero at this time; if the judgment result is no, then it indicates that the current after-treatment catalyst module structure cannot fully process the original NH3 emissions of the ammonia-related engine, and the current after-treatment catalyst module needs to be reconfigured, specifically by re-optimizing the ASC unit of the after-treatment catalyst module.

[0064] Although the functions and working processes of the present invention have been described above in conjunction with the accompanying drawings, the present invention is not limited to the above-mentioned specific functions and working processes. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the purpose of the present invention and the claims, which are all protected by the present invention.

Claims

1. A method for coordinated control of pollutant emissions from ammonia-related engines, characterized in that: include: Real-time monitoring of pollutant concentrations and components in the raw exhaust of ammonia-related engines across the entire operating range to obtain the ammonia-nitrogen molar ratio (ANMR) of the raw exhaust of ammonia-related engines. If ANMR is ≤ 1, strategy 1 is used for coordinated control; if ANMR is > 1, strategy 2 is used for coordinated control. Strategy 1: Real-time monitoring of the NOx concentration at the outlet of the pre-stage SCR in the after-treatment catalyst module of an ammonia engine. If the NOx concentration at the outlet of the pre-stage SCR is less than or equal to a threshold of 1, no additional urea injection is required into the after-treatment catalyst module, and the urea injection rate is controlled to zero. If the NOx concentration at the outlet of the pre-stage SCR is greater than the threshold of 1, the urea injection rate into the after-treatment catalyst module is adjusted. Strategy 2: Step S1: Under the premise that the absolute value of the fuel economy loss is not higher than a threshold value 2, the combustion in the cylinder of the ammonia-related engine is optimized by adjusting the fuel injection strategy and the fuel energy distribution strategy of the ammonia-related engine. After the optimization, the concentration and composition of pollutants in the original exhaust gas of the ammonia-related engine are monitored in real time within the full operating range to obtain the ammonia-nitrogen molar ratio ANMR of the original exhaust gas of the ammonia-related engine at that time; if the optimized ANMR is ≤ 1, the cycle is switched to strategy 1 for further control; if the optimized ANMR is still greater than 1, the process is switched to step S2; Step S2: Real-time monitoring of the NH3 concentration at the outlet of the post-treatment catalyst module. If the NH3 concentration at the outlet of the post-treatment catalyst module is less than a threshold value of 3, no additional control is required and the optimized coordinated control ends. If the NH3 concentration at the outlet of the post-treatment catalyst module is greater than or equal to the threshold value of 3, the process proceeds to step S3. Step S3, determining whether the current ammonia engine load rate is greater than or equal to a threshold value 4, if so, looping back to step S1, if not, looping back to step S4; Step S4, determining whether the ammonia energy replacement rate is greater than or equal to a threshold value of 5. If the ammonia energy replacement rate is greater than or equal to the threshold value of 5, the process loops back to step S1; if the ammonia energy replacement rate is less than the threshold value of 5, the process loops back to step S5. Step S5, determining whether the NH3 concentration at the outlet of the post-treatment catalyst module is less than or equal to threshold 3. If the judgment result is yes, no additional urea injection is required into the post-treatment catalyst module, and the urea injection amount is controlled to zero. If the judgment result is no, reconfigure the current post-treatment catalyst module.

2. The method for coordinated control of pollutant emissions from ammonia-related engines according to claim 1, characterized in that: A raw emission concentration monitoring window is set on the exhaust pipe between the turbocharger and the inlet of the post-treatment catalyst module of the ammonia engine. The pollutant concentration and composition in the raw exhaust gas of the ammonia engine are monitored in real time in the raw emission concentration monitoring window under the full operating range. Based on the concentrations of NOx and NH3, the ANMR of the raw emission of the ammonia engine is calculated according to the following formula: ， ， ， Where ANMR is the ammonia nitrogen molar ratio, is the number of moles of NH3, is the number of moles of NOx, is the volume concentration of NH3, is the volume concentration of NOx, It is the engine exhaust volume flow converted to standard conditions according to the ideal gas equation.

3. The method for coordinated control of pollutant emissions from ammonia-related engines according to claim 1, characterized in that: The method is applicable to an ammonia-diesel dual-fuel engine, a pure ammonia engine or an ammonia-hydrogen dual-fuel engine.

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