Fuel supply and exhaust aftertreatment system and method for ammonia-hydrogen fueled engines

Abstract

This invention relates to the field of internal combustion engine technology and provides a fuel supply and exhaust aftertreatment system and method for ammonia-hydrogen fuel engines. The system includes a hydrogen production device, a primary aftertreatment unit, and a secondary aftertreatment unit arranged sequentially along the exhaust pipe, and is equipped with a liquid ammonia tank, an ammonia pressure stabilizing tank, an ammonia separator, a reducing agent pressure stabilizing tank, and an ammonia circulation pump; a first NOx is installed before and after the exhaust pipe. x Concentration sensor, first NH3 concentration sensor, second NO concentration sensor x The invention includes a concentration sensor and a second NH3 concentration sensor. It can match differentiated post-treatment strategies for different operating conditions, improving NO concentration over a wide temperature window. x Improve reduction efficiency, control ammonia slip, and achieve efficient utilization of fuel and reducing agent.

Description

Technical Field

[0001] This invention belongs to the field of internal combustion engine technology, and particularly relates to a fuel supply and exhaust aftertreatment system and method for ammonia-hydrogen fuel engines. Background Technology

[0002] Ammonia, as a carbon-free fuel, is gaining increasing attention in the field of vehicle power. In engine systems fueled by ammonia, it is not only used for in-cylinder combustion to provide power, but it can also be used to produce hydrogen through online cracking as a combustion aid, and as a reducing agent in the selective catalytic reduction reactor of the exhaust aftertreatment system to eliminate nitrogen oxides.

[0003] In existing technologies, the utilization of ammonia mostly follows a single technical path. For example, some solutions guide unburned ammonia from engine exhaust back into the intake system for recirculation, or collect it for aftertreatment. However, these methods operate independently of each system, lacking coordination. Especially under frequent transient operating conditions of automotive engines (such as cold starts, idling, and rapid acceleration), the ammonia requirements of the combustion system, hydrogen production system, and aftertreatment system dynamically change and vary significantly. If fuel ammonia is directly supplied to the aftertreatment system, it will affect the precise control of combustion; if it relies on unburned ammonia in the exhaust, as combustion efficiency improves, the amount of unburned ammonia decreases, and the aftertreatment effect will be greatly reduced.

[0004] Therefore, how to achieve efficient and dynamic allocation and utilization of ammonia fuel at all stages from a system-level perspective is a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0005] The purpose of this invention is to provide a fuel supply and exhaust aftertreatment system and method for ammonia-hydrogen fuel engines, aiming to solve the problems mentioned in the background art.

[0006] This invention is implemented as follows: a fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel cell engine includes a hydrogen production device, a primary aftertreatment unit, and a secondary aftertreatment unit arranged sequentially on the exhaust pipe of the ammonia-hydrogen engine in a direction away from the engine; a first NO₂ is provided on the exhaust pipe between the hydrogen production device and the primary aftertreatment unit. x A concentration sensor and a first NH3 concentration sensor are used to monitor the composition and concentration of the exhaust gas in the ammonia-hydrogen engine; a second NO3 concentration sensor is installed on the exhaust pipe after the secondary aftertreatment system. x Concentration sensor and second NH3 concentration sensor, used to monitor the composition and concentration of post-treated exhaust gas; also includes:

[0007] The liquid ammonia tank is connected to an ammonia pressure stabilizing tank. The output of the ammonia pressure stabilizing tank is connected to an ammonia-hydrogen engine and a hydrogen production device via two pipelines. The output of the hydrogen production device is connected to an ammonia separator. The output of the ammonia separator is provided with two pipelines, one of which is connected to the ammonia-hydrogen engine to transport hydrogen and nitrogen as ignition fuel, and the other is connected to a reducing agent pressure stabilizing tank to transport ammonia as a reducing agent. An ammonia concentration sensor is also provided at the reducing agent pressure stabilizing tank. The output of the reducing agent pressure stabilizing tank is connected to two pipelines, one of which is connected to the ammonia pressure stabilizing tank via an ammonia circulation pump, and the other is connected to both the primary and secondary post-processors. A reducing agent pressure regulating valve is also provided on the pipeline between the reducing agent pressure stabilizing tank and the primary and secondary post-processors.

[0008] In a further technical solution, a hydrogen storage tank is also installed on the pipeline between the ammonia separator and the ammonia-hydrogen engine.

[0009] A further technical solution is that a primary post-processing ammonia injector is provided at the inlet end of the primary post-processor, and a secondary post-processing ammonia injector is provided at the inlet end of the secondary post-processor.

[0010] The primary post-processor is internally filled with Fe-ZSM-5 iron-based molecular sieve catalyst and is equipped with a temperature sensor;

[0011] The secondary post-processor has a series structure. Its front end is provided with a Cu-SSZ-13 copper-based microporous molecular sieve catalyst, and its rear end is provided with a double-layer catalytic structure. The bottom layer is a Pt / Pd-Al2O3 structure, and the top layer is a Cu-SSZ-13 structure.

[0012] Another objective of this invention is to provide a fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel engine, based on the aforementioned aftertreatment system, comprising the following steps:

[0013] Step 1: When the current operating condition is identified as a cold start condition, the first NO at the entry point of the first-level post-processor is activated. x The concentration sensor and the first NH3 concentration sensor detect NO in the exhaust gas. x The NH3 concentration signal is transmitted to the ECU to determine the required amount of ammonia as a reducing agent. If the ammonia in the exhaust gas meets the self-reaction concentration requirement, i.e., the actual ammonia-to-nitrogen concentration ratio... If the condition is met, then no reducing agent ammonia will be sprayed; otherwise, the ECU will output a control signal to the secondary aftertreatment ammonia injector to spray reducing agent ammonia into the secondary aftertreatment unit to reduce NO. x ;

[0014] Step 2: When the current operating condition is detected as idling / low load, the first NO is activated. x Concentration sensors and the first NH3 concentration sensor monitor NO in exhaust gas.x The concentration signal, along with the NH3 concentration, is transmitted to the ECU for comprehensive determination of whether the ammonia concentration in the exhaust meets the self-reaction concentration requirements. ;

[0015] like Control the reducing agent pressure regulating valve to close and prevent ammonia from being sprayed;

[0016] like Then, based on the NH3 concentration and NO concentration in the exhaust gas... x To reduce NO concentration, adjust the opening of the reducing agent pressure regulating valve. At this time, the temperature sensor in the primary post-processor monitors the temperature of the primary post-processor to determine if it has reached its operating temperature. If the primary post-processor has reached its operating temperature, adjust the opening of the reducing agent pressure regulating valve to supply 50% ammonia gas to both the primary and secondary post-processor ammonia injectors for NO reduction. x If the primary post-processor has not yet reached its operating temperature, adjust the opening of the reducing agent pressure regulating valve to supply ammonia only to the secondary post-processor.

[0017] Step 3: When the current operating condition is identified as medium-high load or high load, monitor the NO input of the first-level post-processor. x concentration :

[0018] like ,in The minimum NO to be processed is determined during engine bench calibration. x Emission concentration, Normal NO that needs to be processed is determined during engine bench calibration. x Emission concentration; at this time, the ECU issues a control command to adjust the opening of the reducing agent pressure regulating valve, and provides reducing agent ammonia gas according to the bench calibration baseline ammonia injection value; controls the ammonia injection rate of the primary and secondary aftertreatment ammonia injectors to 50% each; after outputting the ammonia injection command for a few seconds, continues to monitor the NO at the outlet of the secondary aftertreatment unit. x concentration :

[0019] like ,in To comply with emission regulations NO x The emission limits will continue to be implemented using this strategy;

[0020] like or Then adjust the opening of the reducing agent pressure regulating valve to provide approximately 1.1-1.5 times the baseline ammonia value of the reducing agent, based on the bench calibration ammonia injection value; control the primary post-treatment ammonia injector to inject 60% reducing agent ammonia and the secondary post-treatment ammonia injector to inject 40% ammonia; after outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary post-treatment outlet. x concentration :

[0021] like If so, continue to operate under this strategy;

[0022] like or Then adjust the opening of the reducing agent pressure regulating valve to provide approximately 1.5-2 times the baseline ammonia value of the reducing agent, based on the bench calibration ammonia injection value; control the primary post-treatment ammonia injector to inject 80% reducing agent ammonia and the secondary post-treatment ammonia injector to inject 20% ammonia; after outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary post-treatment outlet. x concentration :

[0023] like If so, continue to operate under this strategy;

[0024] like Then run the following program:

[0025] Adjust the opening of the reducing agent pressure regulating valve to supply reducing agent ammonia gas according to the maximum ammonia injection value calibrated on the test bench; if the NO at the outlet of the secondary post-processor is... x concentration If the system still cannot effectively return to the calibrated normal range, the ECU will issue a fault signal and illuminate the fault light to prompt for inspection.

[0026] Step 4: When the current operating condition is identified as rapid acceleration, monitor whether the ammonia concentration in the exhaust gas meets the self-reaction concentration requirements:

[0027] like Control the reducing agent pressure regulating valve to close and prevent ammonia from being sprayed;

[0028] like Then, based on the NH3 concentration and NO concentration in the exhaust gas... x To reduce the concentration, adjust the opening of the reducing agent pressure regulating valve. If switching from idle to rapid acceleration, proceed to step 2. If switching from normal driving to rapid acceleration, the primary aftertreatment unit has reached operating temperature, so control the primary aftertreatment ammonia injector to inject 80% reducing agent ammonia, and the secondary aftertreatment ammonia injector to inject 20% reducing agent ammonia. After outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary aftertreatment unit outlet. x concentration ,Will and Perform a comparison and execute the relevant control strategies in step 3.

[0029] Further technical solutions, actual ammonia nitrogen concentration ratio The calculation formula is as follows:

[0030]

[0031] in, The original NH3 concentration is monitored by the first NH3 concentration sensor before the first-stage post-processor. The original NO for the first-level post-processor entry x Concentration, via the first NO x Concentration sensor monitoring and engine bench calibration MAP viewing.

[0032] In a further technical solution, the post-processing method also includes step 5: dynamically monitoring the NH3 concentration in the exhaust gas in real time through a second NH3 concentration sensor set at the back end of the secondary post-processor;

[0033] If the percentage of data points in the exhaust NH3 concentration that exceed the emission limits specified in the emission regulations is greater than 5%, the ECU will issue an over-limit alarm signal to prompt inspection.

[0034] A further technical solution, the post-processing method also includes step 6: real-time monitoring of the ammonia concentration in the reducing agent pressure stabilizing tank using an ammonia concentration sensor. :

[0035] like While maintaining an 80% ammonia concentration, any excess ammonia will be returned to the ammonia pressure stabilizing tank. This represents the NH3 concentration at full capacity of the reducing agent pressure stabilizing tank.

[0036] The fuel supply and exhaust aftertreatment system and method for ammonia-hydrogen fuel engines provided in this invention have the following beneficial effects:

[0037] (1) System synergy and high fuel utilization: The unreacted ammonia gas that might otherwise be wasted in the hydrogen production process is cleverly used as a reducing agent in the after-treatment system, realizing the cascade utilization of ammonia fuel in the whole chain of "hydrogen production-combustion-after-treatment", without the need to carry urea or rely on unstable exhaust ammonia.

[0038] (2) Strong adaptability to working conditions and precise control: By monitoring exhaust composition and engine working conditions in real time, the amount of ammonia injected is dynamically calculated and corrected. In particular, the ammonia-nitrogen ratio control strategy introduces a correction coefficient, which can accurately cope with various transient working conditions from cold start to high load, ensuring that the aftertreatment system always works in the high-efficiency range.

[0039] (3) Energy can be recovered, making the system more economical: The energy recovery loop can return the unused ammonia reducing agent from the post-treatment system to the ammonia pressure stabilizing tank, further reducing energy waste and improving the economy of the entire power system.

[0040] (4) Optimized structure and good durability: The two-stage post-processor design is designed for low-temperature and high-temperature exhaust respectively, and takes into account the hydrothermal stability problem, which improves the reliability and service life of the system. Attached Figure Description

[0041] Figure 1 This is a schematic diagram of the fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel engine provided in an embodiment of the present invention.

[0042] Figure 2 This is a schematic diagram of the structure of a primary and secondary after-processor in a fuel supply and exhaust after-treatment system for an ammonia-hydrogen fuel engine provided in an embodiment of the present invention.

[0043] Figure 3 This is a control logic diagram of a fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel engine provided in an embodiment of the present invention.

[0044] In the attached diagram: 1. Liquid ammonia tank; 2. Ammonia pressure stabilizing tank; 3. Ammonia circulation pump; 4. Hydrogen storage tank; 5. Ammonia separator; 6. Hydrogen production unit; 7. Reducing agent pressure stabilizing tank; 8. Primary post-processor; 81. Fe-ZSM-5 iron-based molecular sieve catalyst; 82. Temperature sensor; 9. Secondary post-processor; 91. Cu-SSZ-13 copper-based small-pore molecular sieve catalyst; 92. Bilayer catalytic structure; 10. Ammonia concentration sensor; 11. First NO x Concentration sensor 11; First NH3 concentration sensor 12; Second NO concentration sensor 13 x Concentration sensor 13; Second NH3 concentration sensor 14; Reducing agent pressure regulating valve 15; Primary post-treatment ammonia injector 16; Secondary post-treatment ammonia injector 17. Detailed Implementation

[0045] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0046] The specific implementation of the present invention will be described in detail below with reference to specific embodiments.

[0047] like Figure 1 and Figure 2 As shown, an embodiment of the present invention provides a fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel engine, including a hydrogen production device 6, a primary aftertreatment unit 8, and a secondary aftertreatment unit 9 arranged sequentially on the exhaust pipe of the ammonia-hydrogen engine in a direction away from the engine; a first NO₂ is provided on the exhaust pipe between the hydrogen production device 6 and the primary aftertreatment unit 8. xConcentration sensor 11 and first NH3 concentration sensor 12 are used to monitor the composition and concentration of the exhaust gas in the ammonia-hydrogen engine; a second NO3 concentration sensor is installed on the exhaust pipe after the secondary after-treatment unit 9. x Concentration sensor 13 and second NH3 concentration sensor 14 are used to monitor the composition and concentration of the post-treated exhaust gas; also includes:

[0048] A liquid ammonia tank 1 is connected to an ammonia pressure stabilizing tank 2. The output end of the ammonia pressure stabilizing tank 2 is connected to an ammonia-hydrogen engine and a hydrogen production device 6 via two pipelines. The output end of the hydrogen production device 6 is connected to an ammonia separator 5. The output end of the ammonia separator 5 is provided with two pipelines, one of which is connected to the ammonia-hydrogen engine to transport hydrogen and nitrogen as ignition fuel, and the other is connected to a reducing agent pressure stabilizing tank 7 to transport ammonia as a reducing agent. An ammonia concentration sensor 10 is also provided at the reducing agent pressure stabilizing tank 7. The output end of the reducing agent pressure stabilizing tank 7 is connected to two pipelines, one of which is connected to the ammonia pressure stabilizing tank 2 via an ammonia circulation pump 3, and the other is connected to both the primary post-processor 8 and the secondary post-processor 9. A reducing agent pressure regulating valve 15 is also provided on the pipeline between the reducing agent pressure stabilizing tank 7 and the primary and secondary post-processors 8 and 9.

[0049] In this embodiment of the invention, during operation, the fuel ammonia in the liquid ammonia tank 1 is vaporized and pressure-stabilized by the ammonia pressure stabilizing tank 2, and then divided into main fuel ammonia and cracked fuel ammonia. The main fuel ammonia is directly burned in the ammonia-hydrogen engine, while the cracked fuel ammonia is cracked in the hydrogen production unit 6, and the cracked gas is separated in the ammonia separator 5. Hydrogen and nitrogen are used as ignition fuel and directly introduced into the ammonia-hydrogen engine for combustion. The separated ammonia is introduced into the reducing agent pressure stabilizing tank 7 as a reducing agent. The reducing agent pressure stabilizing tank 7 adjusts the ammonia injection rate in real time according to the concentration in the tank and the reducing agent requirement. Excess ammonia is returned to the ammonia pressure stabilizing tank 2 via the ammonia circulation pump 3 to achieve energy recovery.

[0050] like Figure 1 As shown in the preferred embodiment of the present invention, a hydrogen storage tank 4 is also provided on the pipeline between the ammonia separator 5 and the ammonia-hydrogen engine.

[0051] like Figure 1 and Figure 2 As shown, in a preferred embodiment of the present invention, the inlet end of the primary post-processor 8 is provided with a primary post-processor ammonia injector 16, and the inlet end of the secondary post-processor 9 is provided with a secondary post-processor ammonia injector 17.

[0052] The interior of the primary post-processor 8 is filled with Fe-ZSM-5 iron-based molecular sieve catalyst 81 and is equipped with a temperature sensor 82;

[0053] The secondary post-processor 9 has a series structure. Its front end contains a Cu-SSZ-13 copper-based microporous molecular sieve catalyst 91, and its rear end contains a bilayer catalytic structure 92. The bottom layer is a Pt / Pd-Al2O3 structure, and the top layer is a Cu-SSZ-13 structure, used to oxidize the NO generated from the bottom layer NH3. x The copper-based microporous molecular sieve at the top layer is reduced back to N2.

[0054] In this embodiment of the invention, a two-stage aftertreatment system is designed in the exhaust pipe to match differentiated aftertreatment control strategies for exhaust gases at different temperatures. The first-stage aftertreatment system 8 is located near the exhaust end of the ammonia-hydrogen engine, and the catalyst is selected from Fe-ZSM-5 iron-based molecular sieve. The ideal operating temperature of this catalyst is 400-600℃, and it mainly handles the NO in the high-temperature exhaust. x Reduction. The primary post-processor ammonia injector 16, located at the front end, is used to inject the reducing agent into the primary post-processor 8; the temperature sensor 82 is used to monitor whether the primary post-processor 8 has reached the working temperature so as to adjust the working status of the two-stage post-processors in a coordinated manner.

[0055] The secondary post-processor 9 is mainly responsible for removing NO from low-temperature exhaust gas under low-load conditions such as cold starts. x Reduction and NH3 reduction and treatment of residual NO in the pre-stage x The work involves a series integrated structure of SCR and ASC. The front-end Cu-SSZ-13 copper-based microporous molecular sieve catalyst 91 exhibits good activity in low-temperature exhaust gases below 350°C, and is therefore positioned away from the exhaust end of the ammonia-hydrogen engine. The rear-end employs a double-layer catalytic structure 92 to oxidize the NO generated from the bottom layer of NH3. x The nitrogen is reduced back to N2 through the copper-based microporous molecular sieve at the top layer. Furthermore, the high-temperature water vapor in the exhaust of the ammonia-hydrogen engine poses a challenge to the hydrothermal stability of the catalyst as it passes through. Although the exhaust temperature of the ammonia-hydrogen engine is only around 650°C at most, and the exhaust temperature after the aftertreatment process may be relatively lower, considering the long-term durability of the aftertreatment process, Al2O3 or SiO2 surface passivation processes can be used to effectively suppress phenomena such as active component migration and framework collapse.

[0056] like Figure 3 As shown, this invention provides a fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel cell engine. Based on the aforementioned aftertreatment system, the ECU collects information such as intake pressure, torque, engine speed, and exhaust temperature to comprehensively determine the operating conditions of the ammonia-hydrogen engine, and matches corresponding aftertreatment control strategies according to different operating conditions. During engine bench calibration, the expected ammonia demand is determined by calibrating the exhaust ammonia and nitrogen oxide concentrations under different operating conditions, thereby determining the reductant injection quantity. The NO in the exhaust is calibrated... xThe concentration of NH3 is used to determine the ammonia injection rate in the aftertreatment control system. The basic ammonia injection rate formula can be expressed as:

[0057]

[0058] in, Based on the mass flow rate of ammonia injection, The exhaust mass flow rate is calculated by adding the intake air flow rate and the fuel flow rate. The original NO for the first-level post-processor entry x Concentration (ppm), via the first NO x Concentration sensor 11 monitoring, engine bench calibration MAP view; NO for secondary post-processor output x Concentration (ppm), i.e., NO that complies with emission regulations x Emission values; To estimate the conversion efficiency of SCR, bench tests were conducted to calibrate the efficiency based on factors such as exhaust temperature, space velocity, and catalyst aging rate. The original NH3 concentration is monitored by the first NH3 concentration sensor 12 before the first-stage post-processor 8. The molar ammonia-nitrogen ratio is given.

[0059] In ammonia-hydrogen engines, the concentration of ammonia in emissions varies considerably depending on operating conditions. Therefore, the actual ammonia-nitrogen concentration ratio is introduced. :

[0060]

[0061] Studies have shown that due to differences in exhaust gas concentration under different operating conditions, the SCR system performs best when the ammonia-to-nitrogen ratio is 1.0-1.4. Therefore, the corrected ammonia injection flow rate requirement is:

[0062]

[0063] in, The corrected ammonia injection flow rate. This is the ammonia injection multiplier, used when the NH3 concentration in the exhaust gas is less than that of NO. x The correction of excessive ammonia injection by controlling the reducing agent is achieved by multiplying the ammonia injection to control the ammonia-nitrogen ratio in the exhaust at 1.0-1.4. The ammonia injection multiplication factor is determined by the calibration MAP diagram during engine bench calibration.

[0064] Step 1: When the current operating condition is identified as a cold start, due to the difficulty in igniting pure ammonia in an ammonia-hydrogen engine, cold starts are usually initiated by ignition of pure hydrogen or ammonia-hydrogen co-firing. At this time, the hydrogen production unit 6 has not reached its operating temperature, and the cracked gas pressure regulating valve controls the ignition gas source, which is supplied by the hydrogen storage tank 4. When pure hydrogen is ignited, only a small amount of NO is present in the exhaust of the ammonia-hydrogen engine. xIn ammonia-hydrogen co-combustion, hydrogen provides the primary energy source, while ammonia is present in relatively small quantities. Therefore, the first NO at the inlet of the first-stage post-processor 8... x Concentration sensor 11 and first NH3 concentration sensor 12 detect NO in exhaust gas x The NH3 concentration signal is transmitted to the ECU to determine the required amount of ammonia as a reducing agent. If the ammonia in the exhaust gas meets the self-reaction concentration requirement, then... If the exhaust temperature is too low, the reducing agent ammonia will not be injected. If this condition is not met, the ECU will output a control signal to the corresponding aftertreatment ammonia injector to provide the appropriate amount of reducing agent ammonia. At this time, the exhaust temperature is too low to meet the activation reaction temperature of the iron-based catalyst, and the conversion efficiency of the first-stage aftertreatment unit 8 is low. Therefore, reducing agent ammonia is injected into the second-stage aftertreatment unit 9 through the second-stage aftertreatment ammonia injector 17 to reduce NO. x ;

[0065] Step 2: When the current operating condition is detected as idling / low load, the combustion temperature is low, resulting in incomplete combustion and a higher concentration of unburned ammonia and lower concentration of NO in the exhaust. x Therefore, through the first NO x Concentration sensor 11 and first NH3 concentration sensor 12 monitor NO in exhaust gas x The concentration signal, along with the NH3 concentration, is transmitted to the ECU for comprehensive determination of whether the ammonia concentration in the exhaust meets the self-reaction concentration requirements. .

[0066] like That is, the concentration of ammonia in the exhaust gas can reduce NO x Complete restoration; at this point, control the reducing agent pressure regulating valve 15 to close and stop ammonia injection.

[0067] like Then, based on the NH3 concentration and NO concentration in the exhaust gas... x To reduce NO concentration, adjust the opening of the reducing agent pressure regulating valve 15. At this time, the temperature sensor 82 in the primary post-processor 8 monitors the temperature of the primary post-processor 8 to determine if it has reached its operating temperature. If the primary post-processor 8 has reached its operating temperature, adjust the opening of the reducing agent pressure regulating valve 15 to supply 50% ammonia gas to both the primary post-processor ammonia injector 16 and the secondary post-processor ammonia injector 17 for NO reduction. x If the primary post-processor 8 has not yet reached its operating temperature, adjust the opening of the reducing agent pressure regulating valve 15 to supply ammonia only to the secondary post-processor 9.

[0068] Step 3: When the current operating condition is identified as medium-high load or high load, monitor the NO input of the first-level post-processor. x concentration :

[0069] like ,in The minimum NO to be processed is determined during engine bench calibration. x Emission concentration, Normal NO that needs to be processed is determined during engine bench calibration. x Emission concentration; at this time, the ECU issues a control command to adjust the opening of the reducing agent pressure regulating valve, and provides reducing agent ammonia gas according to the bench calibration baseline ammonia injection value; controls the ammonia injection rate of the primary and secondary aftertreatment ammonia injectors to 50% each; after outputting the ammonia injection command for a few seconds, continues to monitor the NO at the outlet of the secondary aftertreatment unit. x concentration :

[0070] like ,in To comply with emission regulations NO x The emission limits will continue to be implemented using this strategy;

[0071] like or Then adjust the opening of the reducing agent pressure regulating valve to provide approximately 1.1-1.5 times the baseline ammonia value of the reducing agent, based on the bench calibration ammonia injection value; control the primary post-treatment ammonia injector to inject 60% reducing agent ammonia and the secondary post-treatment ammonia injector to inject 40% ammonia; after outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary post-treatment outlet. x concentration :

[0072] like If so, continue to operate under this strategy;

[0073] like or Then adjust the opening of the reducing agent pressure regulating valve to provide approximately 1.5-2 times the baseline ammonia value of the reducing agent, based on the bench calibration ammonia injection value; control the primary post-treatment ammonia injector to inject 80% reducing agent ammonia and the secondary post-treatment ammonia injector to inject 20% ammonia; after outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary post-treatment outlet. x concentration :

[0074] like If so, continue to operate under this strategy;

[0075] like Then run the following program:

[0076] Adjust the opening of the reducing agent pressure regulating valve to supply reducing agent ammonia gas according to the maximum ammonia injection value calibrated on the test bench; if the NO at the outlet of the secondary post-processor is... x concentration If the system still cannot effectively return to the calibrated normal range, the ECU will issue a fault signal and illuminate the fault light to prompt for inspection.

[0077] Step 4: When the current operating condition is identified as rapid acceleration, monitor whether the ammonia concentration in the exhaust gas meets the self-reaction concentration requirements:

[0078] like Control the reducing agent pressure regulating valve to close and prevent ammonia from being sprayed;

[0079] like Then, based on the NH3 concentration and NO concentration in the exhaust gas... x To reduce the concentration, adjust the opening of the reducing agent pressure regulating valve. If switching from idle to rapid acceleration, proceed to step 2. If switching from normal driving to rapid acceleration, the primary aftertreatment unit has reached operating temperature, so control the primary aftertreatment ammonia injector to inject 80% reducing agent ammonia, and the secondary aftertreatment ammonia injector to inject 20% reducing agent ammonia. After outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary aftertreatment unit outlet. x concentration ,Will and Perform a comparison and execute the relevant control strategies in step 3.

[0080] Preferably, in the ammonia-hydrogen hybrid power system, the high-power discharge of the battery powers the motor, thereby providing instantaneous torque response and compensating for the torque build-up delay of the ammonia-hydrogen engine. At this time, the ammonia-hydrogen engine rapidly adjusts to its maximum power or thermal efficiency point, which falls within the medium-to-high load or high external characteristic load operating range, driven by exhaust NO. x The concentration sensor and NH3 concentration sensor monitor the concentration changes in the exhaust gas. The ECU determines the amount of ammonia required as a reducing agent and the corresponding aftertreatment ammonia injection control strategy. Therefore, the aftertreatment system executes the relevant strategy in step 3 at this time.

[0081] Step 5: When designing and bench calibrating the ASC (Automatic Aftertreatment System) structure for the ammonia-hydrogen engine, the control of the maximum NH3 escape in the exhaust should be taken into account. However, during actual vehicle operation, abnormal phenomena such as frequent misfires caused by ammonia-hydrogen engine malfunctions, ammonia injection control failures, and damage to the aftertreatment system may occur. These phenomena will cause the NH3 concentration in the exhaust to exceed the standard instantaneously and significantly, failing to meet emission standards. Therefore, a second NH3 concentration sensor 14 is installed at the rear end of the secondary aftertreatment system 9 to dynamically monitor the NH3 concentration in the exhaust in real time.

[0082] If the NH3 concentration in the exhaust gas occasionally exceeds the emission limit for a short period of time, it may be due to the after-treatment system's transient response being untimely caused by frequent switching of operating conditions, resulting in the NH3 concentration exceeding the standard. If the duration is short or the occurrence is infrequent, it is considered an acceptable NH3 emission, and the exhaust NH3 concentration should continue to be monitored.

[0083] If the percentage of data points in the exhaust NH3 concentration that exceed the emission limits specified in the emission regulations is greater than 5%, the ECU will issue an over-limit alarm signal to prompt inspection.

[0084] Step 6: In an ammonia-hydrogen fusion engine, as the load increases, the flow rate of the cracked gas increases, but the cracking efficiency decreases to some extent with the increase in gas flow rate. At this time, the amount of unreacted ammonia in the cracked gas increases, thus increasing the flow rate of ammonia used as a reducing agent. Heavy-duty commercial vehicles operate under high-load conditions for extended periods, and the demand for reducing agent in the aftertreatment system is relatively stable. Therefore, while meeting the aftertreatment requirements, excess ammonia in the reducing agent pressure stabilizing tank 7 is returned to the ammonia pressure stabilizing tank 2 to participate in main fuel supply or cracking, achieving energy recovery. The ammonia concentration sensor 10 in the reducing agent pressure stabilizing tank 7 monitors the ammonia concentration in the tank in real time. :

[0085] like That is, when the ammonia concentration in the tank is lower than the full-scale ammonia concentration, the ammonia in the tank is not recovered for energy replenishment, but continues to provide ammonia as a reducing agent for post-processing. The NH3 concentration at full scale in the reducing agent pressure stabilizing tank;

[0086] like This means that at this point, the tank can maintain an 80% ammonia concentration, which is sufficient for post-treatment reduction of NO. x When in use, the portion of ammonia gas exceeding 80% concentration will be returned to the ammonia pressure stabilizing tank 2 to achieve energy recovery.

[0087] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel engine, characterized in that, This includes a hydrogen production unit, a primary after-treatment unit, and a secondary after-treatment unit arranged sequentially in the direction away from the ammonia-hydrogen engine's exhaust pipe; a first NO₂ is installed on the exhaust pipe between the hydrogen production unit and the primary after-treatment unit. x A concentration sensor and a first NH3 concentration sensor; a second NO concentration sensor is provided on the exhaust pipe after the secondary post-processor. x Concentration sensor and second NH3 concentration sensor; also includes: The liquid ammonia tank is connected to an ammonia pressure stabilizing tank. The output of the ammonia pressure stabilizing tank is connected to an ammonia-hydrogen engine and a hydrogen production device via two pipelines. The output of the hydrogen production device is connected to an ammonia separator. The output of the ammonia separator is provided with two pipelines, one of which is connected to the ammonia-hydrogen engine to transport hydrogen and nitrogen as ignition fuel, and the other is connected to a reducing agent pressure stabilizing tank to transport ammonia as a reducing agent. An ammonia concentration sensor is also provided at the reducing agent pressure stabilizing tank. The output of the reducing agent pressure stabilizing tank is connected to two pipelines, one of which is connected to the ammonia pressure stabilizing tank via an ammonia circulation pump, and the other is connected to both the primary and secondary post-processors. A reducing agent pressure regulating valve is also provided on the pipeline between the reducing agent pressure stabilizing tank and the primary and secondary post-processors.

2. The fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel engine according to claim 1, characterized in that, A hydrogen storage tank is also installed on the pipeline between the ammonia separator and the ammonia-hydrogen engine.

3. The fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel engine according to claim 2, characterized in that, The inlet of the first-stage post-processor is equipped with a first-stage post-processor ammonia injector, and the inlet of the second-stage post-processor is equipped with a second-stage post-processor ammonia injector. The primary post-processor is internally filled with Fe-ZSM-5 iron-based molecular sieve catalyst and is equipped with a temperature sensor; The secondary post-processor has a series structure. Its front end is provided with a Cu-SSZ-13 copper-based microporous molecular sieve catalyst, and its rear end is provided with a double-layer catalytic structure. The bottom layer is a Pt / Pd-Al2O3 structure, and the top layer is a Cu-SSZ-13 structure.

4. A fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel engine, based on the fuel supply and exhaust aftertreatment system for an ammonia-hydrogen fuel engine as described in claim 3, characterized in that, Includes the following steps: Step 1: When the current operating condition is identified as a cold start condition, the first NO at the entry point of the first-level post-processor is activated. x The concentration sensor and the first NH3 concentration sensor detect NO in the exhaust gas. x The NH3 concentration signal is transmitted to the ECU to determine the required amount of ammonia as a reducing agent. If the ammonia in the exhaust gas meets the self-reaction concentration requirement, i.e., the actual ammonia-to-nitrogen concentration ratio... If the condition is met, then no reducing agent ammonia will be sprayed; otherwise, the ECU will output a control signal to the secondary aftertreatment ammonia injector to spray reducing agent ammonia into the secondary aftertreatment unit to reduce NO. x ; Step 2: When the current operating condition is detected as idling / low load, the first NO is activated. x Concentration sensors and the first NH3 concentration sensor monitor NO in exhaust gas. x The concentration signal, along with the NH3 concentration, is transmitted to the ECU for comprehensive determination of whether the ammonia concentration in the exhaust meets the self-reaction concentration requirements. ; like Control the reducing agent pressure regulating valve to close and prevent ammonia from being sprayed; like Then, based on the NH3 concentration and NO concentration in the exhaust gas... x To reduce NO concentration, adjust the opening of the reducing agent pressure regulating valve. At this time, the temperature sensor in the primary post-processor monitors the temperature of the primary post-processor to determine if it has reached its operating temperature. If the primary post-processor has reached its operating temperature, adjust the opening of the reducing agent pressure regulating valve to supply 50% ammonia gas to both the primary and secondary post-processor ammonia injectors for NO reduction. x If the primary post-processor has not yet reached its operating temperature, adjust the opening of the reducing agent pressure regulating valve to supply ammonia only to the secondary post-processor. Step 3: When the current operating condition is identified as medium-high load or high load, monitor the NO input of the first-level post-processor. x concentration : like ,in The minimum NO to be processed is determined during engine bench calibration. x Emission concentration, Normal NO that needs to be processed is determined during engine bench calibration. x Emission concentration; at this time, the ECU issues a control command to adjust the opening of the reducing agent pressure regulating valve, and provides reducing agent ammonia gas according to the bench calibration baseline ammonia injection value; controls the ammonia injection rate of the primary and secondary aftertreatment ammonia injectors to 50% each; after outputting the ammonia injection command for a few seconds, continues to monitor the NO at the outlet of the secondary aftertreatment unit. x concentration : like ,in To comply with emission regulations NO x The emission limits will continue to be implemented using this strategy; like or Then adjust the opening of the reducing agent pressure regulating valve to provide approximately 1.1-1.5 times the baseline ammonia value of the reducing agent, based on the bench calibration ammonia injection value; control the primary post-treatment ammonia injector to inject 60% reducing agent ammonia and the secondary post-treatment ammonia injector to inject 40% ammonia; after outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary post-treatment outlet. x concentration : like If so, continue to operate under this strategy; like or Then adjust the opening of the reducing agent pressure regulating valve to provide approximately 1.5-2 times the baseline ammonia value of the reducing agent, based on the bench calibration ammonia injection value; control the primary post-treatment ammonia injector to inject 80% reducing agent ammonia and the secondary post-treatment ammonia injector to inject 20% ammonia; after outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary post-treatment outlet. x concentration : like If so, continue to operate under this strategy; like Then run the following program: Adjust the opening of the reducing agent pressure regulating valve to supply reducing agent ammonia gas according to the maximum ammonia injection value calibrated on the test bench; if the NO at the outlet of the secondary post-processor is... x concentration If the system still cannot effectively return to the calibrated normal range, the ECU will issue a fault signal and illuminate the fault light to prompt for inspection. Step 4: When the current operating condition is identified as rapid acceleration, monitor whether the ammonia concentration in the exhaust gas meets the self-reaction concentration requirements: like Control the reducing agent pressure regulating valve to close and prevent ammonia from being sprayed; like Then, based on the NH3 concentration and NO concentration in the exhaust gas... x To reduce the concentration, adjust the opening of the reducing agent pressure regulating valve. If switching from idle to rapid acceleration, proceed to step 2. If switching from normal driving to rapid acceleration, the primary aftertreatment unit has reached operating temperature, so control the primary aftertreatment ammonia injector to inject 80% reducing agent ammonia, and the secondary aftertreatment ammonia injector to inject 20% reducing agent ammonia. After outputting the ammonia injection command for a few seconds, continue monitoring the NO at the secondary aftertreatment unit outlet. x concentration ,Will and Perform a comparison and execute the relevant control strategies in step 3.

5. The fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel engine according to claim 4, characterized in that, Actual ammonia nitrogen concentration ratio The calculation formula is as follows: ； in, The original NH3 concentration is monitored by the first NH3 concentration sensor before the first-stage post-processor. The original NO for the first-level post-processor entry x Concentration, via the first NO x Concentration sensor monitoring and engine bench calibration MAP viewing.

6. The fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel engine according to claim 4, characterized in that, It also includes step 5: dynamically monitoring the NH3 concentration in the exhaust gas in real time through a second NH3 concentration sensor set at the back end of the secondary post-processor; If the percentage of data points in the exhaust NH3 concentration that exceed the emission limits specified in the emission regulations is greater than 5%, the ECU will issue an over-limit alarm signal to prompt inspection.

7. The fuel supply and exhaust aftertreatment method for an ammonia-hydrogen fuel engine according to claim 4, characterized in that, It also includes step 6: real-time monitoring of the ammonia concentration in the reducing agent pressure stabilizing tank using an ammonia concentration sensor. : like While maintaining an 80% ammonia concentration, any excess ammonia will be returned to the ammonia pressure stabilizing tank. This represents the NH3 concentration at full capacity of the reducing agent pressure stabilizing tank.

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