A method for controlling ammonia-related engine pollutant emissions

Abstract

The application discloses a kind of ammonia-related engine pollution emission in and out collaborative control method: ANMR≤1 uses strategy 1, otherwise uses strategy 2;Strategy 1: ammonia-related engine post-processing catalyst module in front SCR export NOx concentration≤threshold 1, control urea injection amount is zero, otherwise correction urea injection amount;Strategy 2: S1 in the absolute value of fuel economy loss≤threshold 2 under the premise, optimize ammonia-related engine in-cylinder combustion, after optimization ANMR≤1 turn to strategy 1, otherwise turn to S2;S2 post-processing catalyst module export NH3 concentration<threshold 3, collaborative control ends, otherwise turn to S3;S3 ammonia-related engine load rate≥threshold 4, cycle to S1, otherwise turn to S4;S4 ammonia energy replacement rate≥threshold 5, cycle to S1, otherwise turn to S5;S5 post-processing catalyst module export NH3 concentration≤threshold 3, control urea injection amount is zero, otherwise reconfiguration post-processing catalyst module.The application guarantees that engine is installed with post-processing system, and economy is basically unchanged.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of advanced aftertreatment coordination and in-cylinder optimization and control strategy of ammonia involved engine, more particularly, it relates to a kind of ammonia involved engine pollutant emission in-cylinder and aftertreatment coordination control method based on original emission ANMR (Ammonia-to-Nitrogen Oxides Molar Ratio, ammonia nitrogen molar ratio) active control. BACKGROUND

[0002] Internal combustion engine, especially heavy-duty internal combustion engine, will still be an important prime mover in road transportation, engineering machinery, shipbuilding and other industries in the foreseeable future due to its good fuel economy, powerful performance, reliability and other advantages. With the promotion of carbon neutralization and carbon peak strategy, it is imperative to gradually use low-carbon / zero-carbon fuel for internal combustion engine. Ammonia can be used as a clean alternative fuel for internal combustion engine as a renewable energy carrier. However, due to the characteristics of ammonia itself, such as difficulty in igniting and slow burning speed, a high-activity fuel is needed to ignite, and diesel is a good and low-cost modification choice.

[0003] The traditional engine aftertreatment system mainly includes catalyst module, urea injection module, etc., wherein the catalyst module is composed of DOC (diesel oxidation catalyst), DPF (particulate filter), SCR (selective catalytic reduction device) and ASC (ammonia escape catalyst). Unlike traditional engines, ammonia involved engines contain ammonia in the fuel gas, and the original emissions of the engine contain ammonia, i.e., the original emissions of ammonia involved engines contain both NH3 and NOx. As the main emission of the engine, the main treatment method at present is to inject urea solution in the aftertreatment system, generate NH3 through pyrolysis of urea solution, and then react with NOx in the SCR module to generate harmless N2 and H2O. The traditional aftertreatment system mainly measures the NOx concentration at the inlet and outlet of the aftertreatment system by arranging NOx sensors at the inlet and outlet of the aftertreatment system, and calculates the urea injection amount and correction factor based on the measured NOx concentration. However, for ammonia involved engines, there is gaseous NH3 in the original emissions, and the concentration of gaseous NH3 in the exhaust gas changes with the engine speed and load. At present, there is a lack of small-sized and suitable NH3 sensors to directly test the NH3 concentration in the exhaust gas to provide a basis for urea solution injection in the aftertreatment system.

[0004] In summary, in order to make ammonia involved engines meet emission regulations while minimizing the reduction in fuel economy caused by the addition of aftertreatment systems, it is necessary to solve the contradiction between NH3 in the original emissions of ammonia involved engines and the control strategy of aftertreatment systems from the perspective of in-cylinder combustion process and in combination with the control strategy of aftertreatment systems. SUMMARY

[0005] The purpose of the present application is to overcome the deficiencies in the prior art, and provide an ammonia-related engine pollutant emission in-machine and out-of-machine collaborative control method based on original emission ANMR active control, which ensures that the engine remains basically unchanged in economy after the aftertreatment system is added, while the emission meets the regulatory requirements.

[0006] The purpose of the present application is realized through the following technical solutions.

[0007] An ammonia-related engine pollutant emission in-machine and out-of-machine collaborative control method comprises:

[0008] Real-time monitoring of pollutant concentration and components in original exhaust gas in the full operating range of the ammonia-related engine is performed to obtain the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine. If ANMR≤1, strategy 1 is adopted for collaborative control, and if ANMR>1, strategy 2 is adopted for collaborative control.

[0009] Strategy 1: Real-time monitoring of NOx concentration at the outlet of the front-stage SCR in the aftertreatment catalyst module of the ammonia-related engine is performed. If the NOx concentration at the outlet of the front-stage SCR is ≤threshold value 1, no additional urea injection is required in the aftertreatment catalyst module, and at this time, the urea injection amount is controlled to be zero. If the NOx concentration at the outlet of the front-stage SCR is >threshold value 1, the urea injection amount of the aftertreatment catalyst module is corrected.

[0010] Strategy 2:

[0011] Step S1: On the premise that the absolute value of fuel economy loss is not higher than threshold value 2, the in-cylinder combustion of the ammonia-related engine is optimized by adjusting the fuel injection strategy and fuel energy distribution strategy of the ammonia-related engine. After optimization, real-time monitoring of pollutant concentration and components in original exhaust gas in the full operating range of the ammonia-related engine is performed to obtain the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine at this time. If the optimized ANMR≤1, the process is cycled back to strategy 1 for further regulation, and if the optimized ANMR is still >1, the process is transferred to step S2.

[0012] Step S2: Real-time monitoring of NH3 concentration at the outlet of the aftertreatment catalyst module is performed. If the NH3 concentration at the outlet of the aftertreatment catalyst module is <threshold value 3, no additional control is required, and the optimization collaborative control is ended. If the NH3 concentration at the outlet of the aftertreatment catalyst module is ≥threshold value 3, the process is transferred to step S3.

[0013] Step S3: It is judged whether the current ammonia-related engine load rate is greater than or equal to threshold value 4. If yes, the process is cycled back to step S1, and if no, the process is transferred to step S4.

[0014] Step S4: It is judged whether the ammonia energy replacement rate is greater than or equal to threshold value 5. If the ammonia energy replacement rate is ≥threshold value 5, the process is cycled back to step S1, and if the ammonia energy replacement rate is <threshold value 5, the process is transferred to step S5.

[0015] Step S5, judging whether the NH3 concentration at the outlet of the aftertreatment catalyst module is less than or equal to threshold 3, if the result is yes, no additional urea injection is needed in the aftertreatment catalyst module, at this time, the urea injection amount is controlled to be zero, if the result is no, the current aftertreatment catalyst module is reconfigured.

[0016] Further, an original emission concentration monitoring window is arranged on the exhaust pipe between the turbocharger of the ammonia-related engine and the inlet of the aftertreatment catalyst module, the pollutant concentration and components in the original exhaust gas in the full working condition range of the ammonia-related engine are monitored in real time at the original emission concentration monitoring window, according to the concentrations of NOx and NH3, the ANMR of the original emission of the ammonia-related engine is calculated according to the following formula:

[0017] ,

[0018] ,

[0019] ,

[0020] In the formula, 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, is the engine exhaust gas volume flow under standard conditions according to the ideal gas equation.

[0021] Further, the method of the present application is suitable for ammonia-diesel dual-fuel engines, pure ammonia engines or ammonia-hydrogen dual-fuel engines.

[0022] Compared with the prior art, the technical scheme of the present application has the beneficial effects that:

[0023] The present application includes a complete pollutant emission optimization strategy and an online pollutant emission control strategy for ammonia-related engines, i.e., the strategy 1, the strategy 2 and the attached input conditions and output optimization directions.

[0024] Since the theoretical ANR required for NOx reduction in the aftertreatment system is 1, for ammonia-related engines, since the exhaust gas naturally contains ammonia and NOx, in the present application, a parameter ANMR is defined, which is a key parameter for pollutant optimization and urea injection amount control of the aftertreatment system of ammonia-related engines, and is one of the core parameters of the control strategy of the present application, and the use of strategy 1 or strategy 2 for cooperative control is determined by judging the size of ANMR.

[0025] Strategy 1 is to control the urea according to the judgment of the NOx concentration of the front-stage SCR outlet of the aftertreatment catalyst module in the aftertreatment system.

[0026] One of the possible results obtained through the optimization of strategy 2 is to re-optimize the ASC of the aftertreatment, which also indicates the direction of optimization required when the aftertreatment system used in the current test cannot meet the requirements of the ammonia-involved engine exhaust treatment.

[0027] The current load rate of the ammonia-involved engine in strategy 2 ≥ threshold value 4 and the ammonia energy replacement rate ≥ threshold value 5 are the boundary conditions for optimizing the performance and pollutant emission of the ammonia-involved dual-fuel engine in the full load range, so as to as far as possible improve the ammonia replacement rate in the full load range of the ammonia-involved engine and effectively control the pollutant emission level, so that the engine can be operated efficiently and cleanly. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 The flow chart of the ammonia-involved engine pollutant emission in-and-out synergistic control method of the present application.

[0029] Figure 2 The ammonia-diesel dual-fuel engine with an aftertreatment system in the embodiment of the present application.

[0030] Figure 3 The schematic diagram of the aftertreatment catalyst module in the embodiment of the present application.

[0031] The figure legend: 1-ammonia gas cylinder, 2-ammonia gas pressure control equipment, 3-stabilizing pressure tank, 4-ammonia gas rail, 5-ammonia gas injector, 6-diesel oil injector, 7-engine, 8-fuel oil pump, 9-high pressure oil rail, 10-control computer, 11-electronic control module, 12-ammonia supply pipeline, 13-oil supply pipeline, 14-intercooler after pressure sensor, 15-intercooler after temperature sensor, 16-intake pipe, 17-intercooler, 18-turbocharger, 19-turbine after temperature / pressure sensor, 20-aftertreatment 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-aftertreatment outlet NOx concentration sensor, 25-aftertreatment outlet temperature / pressure sensor, 26-front-stage SCR outlet NH3 concentration monitoring window, 27-aftertreatment outlet NH3 concentration monitoring window, 28-urea nozzle, 29-original emission concentration monitoring window, 30-exhaust pipe, 31-aftertreatment catalyst module. DETAILED DESCRIPTION

[0032] In order to make the above objectives, characteristics and advantages of the present application more apparent, comprehensible and easier to be understood, the specific embodiments of the present application will be described in detail below with reference to the drawings, and the above objectives, characteristics and advantages of the present application and other objectives, characteristics and advantages will be more apparent.

[0033] Since there is currently no coordinated control strategy for the coordinated in-cylinder combustion and aftertreatment system control of ammonia-related dual-fuel engine exhaust emissions, the present application proposes an ammonia-related engine pollutant emission in-cylinder and aftertreatment system coordinated control method, as shown in Figure 1 The present application includes the following contents:

[0034] The pollutant concentration and components in the original exhaust of the ammonia-related engine in the full operating range are monitored in real time, and the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine is obtained. When ANMR = 1, it is considered that NH3 in the original emission can completely react with NOx in the original emission, and therefore the concentration of NOx and NH3 at the outlet of the aftertreatment catalyst module can be reduced to below the regulatory requirements under reasonable catalyst configuration. When ANMR < 1, it is necessary to determine whether to inject urea into the aftertreatment catalyst module to convert NOx according to the NOx concentration at the outlet of the aftertreatment catalyst module. Therefore, when the ANMR ≤ 1, the aftertreatment system needs to be mainly controlled, and the essence of the problem is the same. Therefore, when ANMR ≤ 1, the following strategy 1 is adopted for coordinated control, and if ANMR > 1, the following strategy 2 is adopted for coordinated control.

[0035] Preferably, an original emission concentration monitoring window can be arranged on the exhaust pipe between the turbocharger of the ammonia-related engine and the inlet of the aftertreatment catalyst module. The pollutant concentration and components in the original exhaust of the ammonia-related engine in the full operating range are monitored in real time at the original emission concentration monitoring window. According to the concentrations of NOx and NH3, the ANMR of the original emission of the ammonia-related engine is calculated according to the following formula:

[0036] (1),

[0037] (2),

[0038] (3),

[0039] In the formula, 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, To convert the engine exhaust gas volume flow to the standard condition according to the ideal gas equation. ANMR is the ammonia nitrogen molar ratio. Since the theoretical ANR required for the reduction of NOx in the aftertreatment system is 1, for ammonia-related engines, since the exhaust gas naturally contains ammonia and NOx, a parameter ANMR is defined in this invention, which is a key parameter for optimizing pollutants and controlling the amount of urea injection in the aftertreatment system of ammonia-related engines, and is one of the core parameters of the control strategy described in this invention.

[0040] Strategy 1: Real-time monitoring of the NOx concentration at the outlet of the front-stage SCR in the aftertreatment catalyst module of the ammonia-related engine, and determining whether the urea injection amount of the aftertreatment catalyst module needs to be corrected according to the concentration. If the NOx concentration at the outlet of the front-stage SCR is ≤ threshold value 1 (such as 30 ppm, etc.), no additional urea injection is required in the aftertreatment catalyst module, and the control of the urea injection amount is zero at this time. If the NOx concentration at the outlet of the front-stage SCR is > threshold value 1, the urea injection amount of the aftertreatment catalyst module needs to be corrected, and the correction method is to correct the urea injection amount based on the MAP (data table) with ammonia nitrogen molar ratio of 1, and the nitrogen concentration comes from the real-time measured NOx concentration at the outlet of the front-stage SCR in the aftertreatment catalyst module.

[0041] Strategy 2:

[0042] Step S1, under the premise that the absolute value of fuel economy loss is not higher than threshold value 2 (such as 3%, etc.), the in-cylinder combustion of the ammonia-related engine is optimized by adjusting the fuel injection strategy and fuel energy distribution strategy of the ammonia-related engine, such as optimizing the ammonia-related engine pollutant emission level and concentration ratio. After optimization, the pollutant concentration and composition in the original exhaust gas of the ammonia-related engine in the full operating range are monitored in real time, and the ammonia nitrogen molar ratio ANMR of the original emission of the ammonia-related engine at this time can be calculated according to the above formulas (1)-(3); if the optimized ANMR ≤ 1, it is further regulated by circulating to strategy 1; if the optimized ANMR is still > 1, it is transferred to step S2.

[0043] Step S2, real-time monitoring of the NH3 concentration at the outlet of the aftertreatment catalyst module; if the NH3 concentration at the outlet of the aftertreatment catalyst module is < threshold value 3 (such as 10 ppm, etc.), no additional control is required, and the optimization and cooperative control are ended; if the NH3 concentration at the outlet of the aftertreatment catalyst module is ≥ threshold value 3, it is transferred to step S3.

[0044] Step S3, determine whether the current ammonia-related engine load rate is greater than or equal to threshold value 4 (such as 25%, etc.), if yes, it is transferred to step S1 by circulating, if no, it is transferred to step S4.

[0045] Step S4: Determine whether the ammonia energy substitution rate (derived from the fuel energy distribution strategy of the ammonia-based engine) is greater than or equal to the threshold 5. If the ammonia energy substitution rate is greater than or equal to the threshold 5 (e.g., 40%), then proceed to step S1. If the ammonia energy substitution rate is less than the threshold 5, then proceed to step S5.

[0046] Step S5: Determine whether the NH3 concentration at the outlet of the aftertreatment catalyst module is less than or equal to the threshold 3 (e.g., 10 ppm). If the determination result is yes, no additional urea needs to be injected into the aftertreatment catalyst module. At this time, the urea injection amount is controlled to be zero. If the determination result is no, it indicates that the current aftertreatment catalyst module structure cannot completely handle the original NH3 emissions from ammonia-related engines. The current aftertreatment catalyst module needs to be reconfigured, specifically by re-optimizing the ASC unit of the aftertreatment catalyst module.

[0047] The method of the present invention described above is not only applicable to ammonia-diesel dual-fuel engines, but also to extreme cases such as pure ammonia engines where the diesel content is 0%, or to ammonia-related engines such as ammonia-hydrogen dual-fuel engines. Furthermore, the specific values ​​of the thresholds other than threshold 3 (10 ppm) may vary for different ammonia-related engine models.

[0048] Example:

[0049] In this embodiment, the ammonia-related engine is... Figure 2 The ammonia-diesel dual-fuel engine shown in the diagram has a bench hardware system mainly composed of an ammonia cylinder 1, an ammonia pressure control device 2, a pressure stabilizing tank 3, an ammonia gas 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 after-treatment system. The electronic control module 11 can be an ECU. The dashed lines in the diagram represent the electronic control circuitry.

[0050] 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 the high-pressure fuel rail 9 via the fuel pump 8 of the diesel supply system, and then injected into each cylinder of the engine 7 via the fuel supply line 13 and multiple diesel injectors 6. The ammonia supply system is a low-pressure ammonia injection system. Ammonia is supplied from the ammonia cylinder 1 to the ammonia pressure control device 2, then pressure-stabilized by the pressure stabilizing tank 3 and delivered to the ammonia rail 4. Ammonia is then injected into the intake manifold of each cylinder of the engine 7 via the ammonia supply line 12 and multiple ammonia injectors 5. Furthermore, the exhaust port of the engine 7 is connected to the turbine inlet of the turbocharger 18 via the exhaust pipe 30, and the intake port of the engine 7 is connected to the outlet of the intercooler 17 via the intake pipe 16. The inlet of the intercooler 17 is connected to the compressor outlet of the turbocharger 18 via a pipe, and the compressor inlet supplies fresh air. An intercooler pressure sensor 14 and an intercooler temperature sensor 15 are also installed on the intake pipe 16.

[0051] The aftertreatment system of the ammonia-diesel dual fuel engine is arranged behind the turbocharger 18, and the engine exhaust gas is discharged by the exhaust pipe 30 and then enters the aftertreatment system after the turbocharger 18. The aftertreatment system mainly includes a turbine outlet temperature / pressure sensor 19, an aftertreatment system inlet temperature / pressure sensor 20, a front SCR outlet temperature / pressure sensor 21, a front 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 front SCR outlet NH3 concentration monitoring window 26, an aftertreatment outlet NH3 concentration monitoring window 27, a urea nozzle 28, an original emission concentration monitoring window 29, an aftertreatment catalyst module 31, etc.

[0052] As shown in Figure 3 The aftertreatment 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 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 SCR, and the third SCR unit 36 can be referred to as the rear SCR. The turbine outlet temperature / pressure sensor 19 and the original emission concentration monitoring window 29 are arranged on the exhaust pipe between the turbocharger 18 outlet and the aftertreatment catalyst module 31 inlet, the aftertreatment system inlet temperature / pressure sensor 20 is arranged at the first SCR unit 32 inlet, the front SCR outlet temperature / pressure sensor 21 is arranged at the second SCR unit 33 outlet, the front SCR outlet NOx concentration sensor 22, the DPF outlet temperature / pressure sensor 23, the front SCR outlet NH3 concentration monitoring window 26, and the urea nozzle 28 are arranged between the DPF unit 35 outlet and the third SCR unit 36 inlet, the aftertreatment outlet NOx concentration sensor 24 is arranged at the ASC unit 37 outlet, and the aftertreatment outlet temperature / pressure sensor 25 and the aftertreatment outlet NH3 concentration monitoring window 27 are arranged on the exhaust pipe connected to the aftertreatment catalyst module 31 outlet.

[0053] In the present application, three NH3 concentration measuring points are arranged in the bench system, namely the front SCR outlet NH3 concentration monitoring window 26, the aftertreatment outlet NH3 concentration monitoring window 27, and the original emission concentration monitoring window 29, and two NOx concentration sensors are arranged, namely the front SCR outlet NOx concentration sensor 22 and the aftertreatment outlet NOx concentration sensor 24, for monitoring the front SCR outlet NOx concentration and the aftertreatment system NOx concentration. At the same time, the front SCR outlet NOx concentration is also the basis for the strategy 1 to control the urea of the aftertreatment system.

[0054] The pollutant emission in-process and out-of-process collaborative control process of the ammonia-diesel dual fuel engine in this embodiment is as follows:

[0055] The pollutant concentration and components in the original exhaust gas of the ammonia-diesel engine in the full working condition range are monitored in real time in the original emission concentration monitoring window 29. According to the concentrations of NOx and NH3, the ANMR of the original emission of the ammonia-diesel engine is calculated according to formulas (1)-(3). If ANMR≤1, the following strategy 1 is adopted for collaborative control, and if ANMR>1, the following strategy 2 is adopted for collaborative control.

[0056] Strategy 1: The NOx concentration at the outlet of the front-stage SCR of the ammonia-diesel engine is monitored in real time by using the NOx concentration sensor 22 at the outlet of the front-stage SCR, and whether the urea injection amount of the aftertreatment catalyst module needs to be corrected is determined according to the concentration. When ANMR≤1, the aftertreatment system may face two problems, which need to be handled separately. At the same time, according to the existing regulations and giving a certain engineering allowance, the threshold value 1 is set to 30 ppm. When the NOx concentration at the outlet of the front-stage SCR≤30 ppm, it indicates that it has been lower than the limit value of the emission regulation, and at this time, the aftertreatment catalyst module does not need to be additionally injected with urea, and at this time, the urea injection amount is controlled to be zero. When the NOx concentration at the outlet of the front-stage SCR>30 ppm, the urea injection amount of the aftertreatment catalyst module needs to be corrected, and the correction method is to correct the urea injection amount based on the MAP with the ammonia-nitrogen molar ratio of 1, and the nitrogen concentration comes from the NOx concentration at the outlet of the front-stage SCR of the aftertreatment catalyst module monitored in real time by the NOx concentration sensor 22 at the outlet of the front-stage SCR.

[0057] Strategy 2:

[0058] Step S1: The in-cylinder combustion of the ammonia-diesel dual fuel engine needs to be optimized by adjusting the fuel injection strategy and fuel energy distribution strategy of the ammonia-diesel dual fuel engine under the premise that the absolute value of the fuel economy loss is not higher than 3% (threshold value 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≤1, it is further regulated by circulating to strategy 1, and if the optimized ANMR is still >1, it is transferred to step S2.

[0059] Step S2: The NH3 concentration at the outlet of the aftertreatment catalyst module is monitored in real time in the aftertreatment outlet NH3 concentration monitoring window 27. If the NH3 concentration at the outlet of the aftertreatment catalyst module<10 ppm (threshold value 3), no additional control is needed, and the optimization collaborative control is ended. If the NH3 concentration at the outlet of the aftertreatment catalyst module≥10 ppm (threshold value 3), it is transferred to step S3.

[0060] Step S3, judging whether the current ammonia-diesel dual fuel engine load rate is greater than or equal to 25% (threshold 4), if yes, the cycle turns to step S1, if no, it turns to step S4;

[0061] Step S4, judging whether the ammonia energy replacement rate (derived from the fuel energy distribution strategy of the ammonia-diesel dual fuel engine) is greater than or equal to 40% (threshold 5), if the ammonia energy replacement rate is greater than or equal to 40%, the cycle turns to step S1, if the ammonia energy replacement rate is less than 40%, it turns to step S5;

[0062] Step S5, judging whether the real-time monitored outlet NH3 concentration of the aftertreatment catalyst module at the aftertreatment outlet NH3 concentration monitoring window 27 is less than or equal to 10 ppm (threshold 3), if the result is yes, no additional urea injection is needed in the aftertreatment catalyst module, at this time the urea injection amount is controlled to be zero, if the result is no, it indicates that the current aftertreatment catalyst module structure cannot completely treat the original ammonia engine emission NH3, the current aftertreatment catalyst module needs to be reconfigured, which can be specifically re-optimizing the ASC unit of the aftertreatment catalyst module.

[0063] Although the functions and working processes of the present application are described above in combination with the drawings, the present application is not limited to the specific functions and working processes described above, the above specific embodiments are only illustrative, not restrictive, and those skilled in the art can make many forms under the inspiration of the present application without departing from the purpose of the present application and the scope protected by the claims, which all belong to the protection of the present application.

Claims

1. A method for controlling the emission of pollutants from a diesel engine, characterized in that, The method comprises the following steps: Real-time monitoring of the concentration and components of pollutants in the original exhaust gas of the ammonia-related engine in the full working condition range, obtaining the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine, if ANMR≤1, strategy 1 is adopted for collaborative control, if ANMR>1, strategy 2 is adopted for collaborative control; Strategy 1: Real-time monitoring of the NOx concentration at the outlet of the front SCR in the ammonia-related engine aftertreatment catalyst module; if the NOx concentration at the outlet of the front SCR is ≤ threshold 1, no additional urea injection is required in the ammonia-related engine aftertreatment catalyst module, at this time the urea injection amount is controlled to be zero; if the NOx concentration at the outlet of the front SCR is > threshold 1, the urea injection amount of the ammonia-related engine aftertreatment catalyst module is corrected; Strategy 2: Step S1: On the premise that the absolute value of fuel economy loss is not higher than threshold 2, the in-cylinder combustion of the ammonia-related engine is optimized by adjusting the fuel injection strategy and fuel energy distribution strategy of the ammonia-related engine, and the concentration and components of pollutants in the original exhaust gas of the ammonia-related engine in the full working condition range are monitored in real time after optimization, obtaining the ammonia-nitrogen molar ratio ANMR of the original emission of the ammonia-related engine at this time; if the optimized ANMR≤1, it is further regulated by circulating to strategy 1, if the optimized ANMR is still >1, it is transferred to step S2; Step S2: Real-time monitoring of the NH3 concentration at the outlet of the aftertreatment catalyst module, if the NH3 concentration at the outlet of the aftertreatment catalyst module is < threshold 3, no additional control is required, and the optimization collaborative control is ended; if the NH3 concentration at the outlet of the aftertreatment catalyst module is ≥ threshold 3, it is transferred to step S3; Step S3: Determine whether the current ammonia-related engine load rate is greater than or equal to threshold 4, if yes, it is transferred to step S1, if no, it is transferred to step S4; Step S4: Determine whether the ammonia energy replacement rate is greater than or equal to threshold 5, if the ammonia energy replacement rate is ≥ threshold 5, it is transferred to step S1, if the ammonia energy replacement rate is < threshold 5, it is transferred to step S5; Step S5: Determine whether the NH3 concentration at the outlet of the aftertreatment catalyst module is less than or equal to threshold 3, if the result is yes, no additional urea injection is required in the aftertreatment catalyst module, at this time the urea injection amount is controlled to be zero, if the result is no, the current aftertreatment catalyst module is reconfigured.

2. The method of claim 1, wherein the ammonia involved engine exhaust emission control method is characterized by, An original emission concentration monitoring window is arranged on the exhaust pipe between the turbocharger of the ammonia-related engine and the inlet of the aftertreatment catalyst module, the concentration and components of pollutants in the original exhaust gas of the ammonia-related engine in the full working condition range are monitored in real time in the original emission concentration monitoring window, according to the concentrations of NOx and NH3, the ANMR of the original emission of the ammonia-related engine is calculated according to the following formula: ， ， ， where ANMR is the ammonia 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, is the engine exhaust gas volume flow converted to standard conditions according to the ideal gas equation.

3. The method of claim 1, wherein the engine exhaust system is a diesel engine exhaust system. The method is suitable for ammonia-diesel dual-fuel engines, pure ammonia engines or ammonia-hydrogen dual-fuel engines.

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