Injection control method and system for ammonia fuel engine

Abstract

The invention discloses an injection control method and system for an ammonia fuel engine, and relates to the field of ammonia fuel engines. The method comprises the steps that when the ammonia fuel engine is switched from a pure diesel mode to an ammonia-diesel dual-fuel mode, the total energy for maintaining operation of the pure diesel mode is determined; according to the ammonia substitution rate and the total energy under the current working condition, the ammonia fuel injection amount is determined, and ammonia fuel injection is conducted according to the ammonia fuel injection amount; the ammonia concentration output after waste gas discharged by the ammonia fuel engine is treated by a post-treatment system is obtained; if the output ammonia concentration is larger than or equal to the first concentration threshold value, the ammonia concentration and the nitrogen-oxygen concentration of the input end of a mixer in the aftertreatment system are obtained; and if the ammonia concentration and the nitrogen-oxygen concentration of the input end are not zero and the absolute value of the difference value between the ammonia concentration and the nitrogen-oxygen concentration of the input end is smaller than or equal to a second concentration threshold value, the ammonia fuel injection amount is adjusted through a correction factor. According to the invention, ammonia fuel injection can be accurately controlled, and ammonia leakage and excessive emission are prevented.

Description

Technical Field

[0001] The present application relates to the field of ammonia fuel engines, and in particular to an ammonia fuel engine injection control method and system. Background Art

[0002] The development of new low-carbon and zero-carbon alternative fuels and their engine technologies is urgent, and the development of ammonia engines is currently an ideal route. However, most of the existing ammonia fuel engine injection controls do not consider emission control in actual operation, but ammonia fuel engines have problems such as high NOx emissions and a large amount of unburned ammonia, resulting in excessive ammonia emissions. Summary of the invention

[0003] The purpose of the present application is to provide an ammonia fuel engine injection control method and system, which can accurately control the injection of ammonia fuel and prevent ammonia leakage and over-emission.

[0004] To achieve the above objectives, this application provides the following solutions:

[0005] In the first aspect, the present application provides an ammonia fuel engine injection control method, including: when the ammonia fuel engine switches from a pure diesel mode to an ammonia-diesel dual-fuel mode, determining the total energy for maintaining the operation of the pure diesel mode; determining the ammonia fuel injection amount according to the ammonia substitution rate and the total energy under the current operating conditions, and performing ammonia fuel injection according to the ammonia fuel injection amount; obtaining the ammonia concentration output by the exhaust gas emitted by the ammonia fuel engine after being treated by a post-treatment system; if the output ammonia concentration is greater than or equal to a first concentration threshold, obtaining the ammonia concentration and nitrogen oxide concentration at the input end of the mixer in the post-treatment system; if the ammonia concentration and nitrogen oxide concentration at the input end are both not zero, and the absolute value of the difference between the ammonia concentration and the nitrogen oxide concentration at the input end is less than or equal to a second concentration threshold, using a correction factor to adjust the ammonia fuel injection amount.

[0006] In the second aspect, the present application provides an ammonia fuel engine injection control system based on a post-treatment system, including: the ammonia fuel engine injection control system adopts the above-mentioned ammonia fuel engine injection control method to control the ammonia fuel injection amount when the ammonia fuel engine operates in an ammonia-diesel dual-fuel mode.

[0007] According to the specific embodiments provided in this application, this application has the following technical effects:

[0008] The present application provides an ammonia fuel engine injection control method and system. In the ammonia-diesel dual-fuel mode, based on the ammonia concentration output by the after-treatment system and the ammonia concentration and nitrogen oxide concentration at the mixer input end of the after-treatment system, when it is determined that the tail exhaust ammonia concentration of the ammonia fuel engine is too high, a correction factor is used to adjust the ammonia fuel injection amount, accurately control the ammonia fuel injection, and realize closed-loop injection control of the ammonia fuel, effectively preventing ammonia leakage and over-emission. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] In order to more clearly illustrate the technical solutions in the embodiments of the present application or related technologies, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0010] Figure 1 A schematic flow chart of an ammonia fuel engine injection control method provided in one embodiment of the present application;

[0011] Figure 2 A schematic diagram of a pure diesel / ammonia diesel dual fuel mode switching logic provided by another embodiment of the present application;

[0012] Figure 3 A schematic diagram of the principle of an ammonia fuel engine injection control method provided in one embodiment of the present application;

[0013] Figure 4 A schematic diagram of an ammonia engine and a dual SCR after-treatment system provided by another embodiment of the present application;

[0014] Figure 5 This is a schematic diagram of the injection control principle of an ammonia fuel engine based on a dual SCR after-treatment system provided in one embodiment of the present application. DETAILED DESCRIPTION

[0015] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0016] In order to make the above-mentioned objects, features and advantages of the present application more obvious and easy to understand, the present application is further described in detail below with reference to the accompanying drawings and specific implementation methods.

[0017] The nouns appearing in this application are as follows:

[0018] NH3: stands for ammonia, NOx: stands for nitrogen oxides.

[0019] SCR: Selective Catalytic Reduction, a selective catalytic reduction catalyst that converts NOx in exhaust gas when NH3 is injected.

[0020] ASC: Ammonia Slip Catalyst, an ammonia oxidation catalyst, is used to adsorb and convert NH3 leakage in the exhaust gas, but its adsorption capacity is limited.

[0021] Pure diesel mode: The main fuel of the engine is diesel, and no ammonia fuel injection is performed at this time.

[0022] Ammonia-diesel dual-fuel mode: Ammonia fuel is injected at a certain substitution rate, and diesel is used to ignite the ammonia fuel for combustion.

[0023] In an exemplary embodiment, Figure 1 As shown, an ammonia fuel engine injection control method is provided, comprising the following steps 101 to 105. Among them:

[0024] Step 101: When the ammonia fuel engine switches from the pure diesel mode to the ammonia diesel dual fuel mode, the total energy required to maintain the pure diesel mode operation is determined.

[0025] Step 102: Determine an ammonia fuel injection amount according to the ammonia replacement rate and the total energy under the current operating conditions, and perform ammonia fuel injection according to the ammonia fuel injection amount.

[0026] Step 103: Obtaining the ammonia concentration of the exhaust gas emitted by the ammonia fuel engine after being processed by the post-treatment system.

[0027] Step 104: If the output ammonia concentration is greater than or equal to the first concentration threshold, the ammonia concentration and the nitrogen oxide concentration at the mixer input end in the post-treatment system are obtained.

[0028] Step 105: If both the ammonia concentration and the nitrogen oxide concentration at the input end are not zero, and the absolute value of the difference between the ammonia concentration and the nitrogen oxide concentration at the input end is less than or equal to the second concentration threshold, the correction factor is used to adjust the ammonia fuel injection amount.

[0029] By implementing the above steps 101 to 105, in the ammonia-diesel dual-fuel mode, based on the ammonia fuel concentration output by the after-treatment system and the ammonia fuel concentration and nitrogen oxide concentration at the input end, when it is determined that the tail exhaust ammonia concentration of the ammonia fuel engine is too high, a correction factor is used to adjust the ammonia fuel injection amount, accurately control the ammonia fuel injection, and realize closed-loop injection control of the ammonia fuel, effectively preventing ammonia leakage and over-emission.

[0030] In another exemplary embodiment of the present application, the ammonia fuel engine may be an ammonia diesel engine, an ammonia hydrogen engine, an ammonia and dimethyl ether engine, an ammonia and gasoline engine, etc. Ammonia fuel includes ammonia fuel and liquid ammonia, etc.

[0031] In another exemplary embodiment of the present application, the switching from the pure diesel mode to the ammonia-diesel dual-fuel mode in step 101 requires the following conditions to be met simultaneously:

[0032] ① The speed of the ammonia fuel engine is greater than or equal to the lower speed limit, and less than or equal to the upper speed limit.

[0033] ② The torque of the ammonia fuel engine is greater than or equal to the lower torque limit and less than or equal to the upper torque limit.

[0034] ③ The ammonia fuel engine operates in a normal operating mode; the normal operating mode at least includes a non-regeneration mode, a heating mode and a desulfurization mode.

[0035] ④ The temperature of the after-treatment system is greater than or equal to a temperature threshold; the temperature of the after-treatment system is the gas temperature at the input end of the last catalytic converter in the after-treatment system or the gas temperature at the output end of the last catalytic converter in the after-treatment system.

[0036] Figure 2 The pure diesel / ammonia diesel dual fuel mode switching logic is shown. The ammonia fuel engine must meet the following conditions to switch from pure diesel to diesel ammonia fuel dual fuel mode:

[0037] ① The speed meets the requirements, A≤speed≤B; A is the lower speed limit, B is the upper speed limit;

[0038] ② The torque meets the requirements, C≤torque≤D; C is the lower limit of the torque, and D is the upper limit of the torque.

[0039] ③ The engine is in normal operating mode: non-regeneration, heating and desulfurization modes, to prevent the process from entering dual-fuel mode and causing excessive NH3 emissions.

[0040] ④ When the engine switches to the ammonia-diesel dual-fuel mode, the engine is prone to produce a large amount of unburned ammonia due to incomplete combustion. Taking the dual SCR after-treatment system as an example, if the after-treatment temperature is low, the SCR catalyst has low ability to adsorb NH3 and NOx, which makes it easy for NH3 to exceed the standard. Therefore, the temperature of the two-stage SCR after-treatment should be greater than a certain temperature to ensure that emissions do not exceed the regulatory limit in the dual-fuel mode.

[0041] When all the above conditions are met, the pure diesel mode is switched to the ammonia-diesel dual-fuel mode.

[0042] In another exemplary embodiment of the present application, the above step 101 of determining the total energy for maintaining the pure diesel mode operation can be replaced by the following steps 201 to 202:

[0043] Step 201: Obtain the fuel injection amount by querying the ignition control curve diagram according to the rotation speed and throttle of the ammonia fuel engine.

[0044] The ignition control curve diagram is specifically an ignition control curve diagram required by the engine under various operating conditions, which is called a MAP (Manifold Absolute Pressure Sensor) diagram.

[0045] Step 202: Multiply the fuel injection amount by the calorific value to obtain the total energy required to maintain the pure diesel mode operation.

[0046] In another exemplary embodiment of the present application, according to the law of conservation of energy, after entering the ammonia-diesel dual-fuel mode, the energy provided by the ammonia fuel injection plus the partial diesel injection energy equals the total energy of the pure diesel mode.

[0047] Then the process of determining the ammonia fuel injection amount in step 102 can be replaced by the following steps 301 to 303:

[0048] Step 301: Determine the ammonia replacement rate under current operating conditions corresponding to the calibrated throttle opening and speed of the ammonia fuel engine test bench.

[0049] The explosion pressure and maximum exhaust temperature must be monitored during the ammonia replacement rate calibration process.

[0050] Step 302: Multiply the total energy by the ammonia replacement rate under the current operating conditions to obtain the ammonia injection energy.

[0051] Step 303: Divide the ammonia injection energy by the ammonia fuel calorific value to obtain the ammonia fuel injection amount.

[0052] After the ammonia fuel injection amount is obtained, the ammonia fuel injection is performed according to the injection pressure and pulse width.

[0053] In another exemplary embodiment of the present application, after the above step 102, the method may further include the following steps 401 to 402. Among them:

[0054] Step 401: Calculate the diesel injection energy according to the ammonia substitution rate and the total energy under the current operating conditions using the formula C=E×(1-α); wherein C is the diesel injection energy, E is the total energy, and α is the ammonia substitution rate under the current operating conditions.

[0055] Step 402: Divide the diesel injection energy by the diesel calorific value to obtain the diesel injection amount.

[0056] In another exemplary embodiment of the present application, the above step 105 uses a correction factor to adjust the injection amount of ammonia fuel, which can be replaced by the following steps 501 to 503:

[0057] Step 501: multiply the ammonia substitution rate under the current operating conditions by the correction factor to obtain a corrected ammonia substitution rate.

[0058] Step 502: Multiply the total energy by the corrected ammonia replacement rate to obtain corrected ammonia injection energy.

[0059] Step 503: Divide the corrected ammonia injection energy by the ammonia fuel calorific value to obtain the adjusted ammonia fuel injection amount.

[0060] The principle of the ammonia fuel engine injection control method is as follows Figure 3 As shown, Figure 3 The threshold a in is the first concentration threshold, the threshold b is the second concentration threshold, and β is the correction factor.

[0061] In another exemplary embodiment of the present application, the ammonia injection control of the present application is based on a post-treatment system, and the post-treatment system can specifically be a dual SCR post-treatment system. The dual SCR post-treatment system includes a mixer, a first ammonia fuel nozzle, a first-stage catalytic converter, a second-stage catalytic converter, a first ammonia sensor and a nitrogen oxide sensor; the first-stage catalytic converter and the second-stage catalytic converter are both SCR / ASC catalytic converters. The input end of the first-stage catalytic converter is connected to the output end of the ammonia engine; the mixer is located between the output end of the first-stage catalytic converter and the input end of the second-stage catalytic converter; the first ammonia fuel nozzle is arranged in front of the mixer; the first ammonia sensor and the nitrogen oxide sensor are both arranged at the input end of the mixer.

[0062] In another exemplary embodiment of the present application, the dual SCR post-treatment system further includes: a second ammonia fuel sensor, a first temperature sensor, and a second temperature sensor. The first temperature sensor is disposed at the input end of the second-stage catalytic converter, and the second ammonia fuel sensor and the second temperature sensor are both disposed at the output end of the second-stage catalytic converter.

[0063] In another exemplary embodiment of the present application, referring to Figure 4 A nitrogen oxide sensor is also provided at the output end of the second-stage catalytic converter to detect the nitrogen oxide concentration output by the post-treatment system.

[0064] Figure 4 Schematic diagram of the ammonia engine and dual SCR after-treatment system. Figure 4The intake system of the medium-ammonia engine is composed of an air filter, a compressor, an intercooler, and a throttle valve. Fresh air is mixed with ammonia fuel injected from the second ammonia fuel nozzle at the intake manifold and then enters the cylinder to participate in combustion. The direct injection combustion aid in the cylinder can be but is not limited to diesel, hydrogen, and dimethyl ether. The exhaust gas after cylinder combustion is discharged after the turbine works. The exhaust gas passes through the first-stage SCR / ASC. There is no reductant injection device before the first-stage SCR / ASC. Only unburned ammonia fuel in the exhaust gas is used to convert NOx. A mixer is connected after the first-stage SCR / ASC. The first ammonia fuel nozzle is installed before the mixer. The NOx sensor, ammonia sensor, and temperature sensor between the two-stage SCR are used as input boundaries. Ammonia fuel injection is performed through logical judgment. The first ammonia sensor and a nitrogen oxide sensor are installed between the mixer and the first-stage SCR / ASC. The first temperature sensor T1 is installed between the second-stage SCR / ASC and the mixer. The second ammonia sensor, another nitrogen oxide sensor, and the second temperature sensor T2 are arranged after the second-stage SCR / ASC.

[0065] In another exemplary embodiment of the present application, when the post-treatment system is a dual SCR post-treatment system, the above step 105 can be replaced by the following steps 601 to 602:

[0066] Step 601: If the ammonia fuel concentration measured by the first ammonia fuel sensor and the nitrogen oxide concentration measured by the nitrogen oxide sensor are both not zero, and the absolute value of the difference between the ammonia fuel concentration measured by the first ammonia fuel sensor and the nitrogen oxide concentration measured by the nitrogen oxide sensor is less than or equal to the second concentration threshold, a correction factor is used to reduce the ammonia fuel injection amount injected by the second ammonia fuel nozzle.

[0067] Step 602: Otherwise, the correction factor is used to reduce the injection amount of the ammonia reducing agent injected by the first ammonia fuel injector.

[0068] Figure 5 This is the injection control schematic diagram of an ammonia fuel engine based on a dual SCR after-treatment system. Figure 5 The control logic shown is as follows:

[0069] The conditions for the dual-fuel mode jump are judged. If they are met, the MAP is checked through the engine speed and throttle to obtain the fuel injection amount corresponding to the working condition in the pure diesel mode. The total energy to maintain the operation of this working condition is obtained by multiplying the diesel injection amount by the calorific value. According to the law of conservation of energy, after entering the dual-fuel mode, the energy provided by the ammonia fuel injection and the diesel injection energy are equal to the total energy of the pure diesel mode. The ammonia substitution rate under the corresponding working conditions of the throttle opening and speed is calibrated on the engine bench (the explosion pressure and the maximum exhaust temperature must be monitored during the calibration process of the ammonia substitution rate). The total energy is multiplied by the ammonia substitution rate to obtain the ammonia injection energy. The ammonia injection energy is divided by the ammonia fuel calorific value to obtain the ammonia nozzle injection amount, and then the ammonia fuel is injected according to the injection pressure and pulse width. The dual-fuel mode must consider the ability of the aftertreatment to convert unburned ammonia, and the ammonia substitution rate is transiently corrected according to the measurement readings of the NOx and NH3 sensors of the aftertreatment system. When the second NH3 sensor is greater than or equal to the threshold a, it indicates that the post-treatment system faces the risk of NH3 over-emission, but it is necessary to determine the ammonia injection over-standard, and analyze which of the first ammonia nozzle and the second ammonia nozzle caused the NH3 leakage. If the first ammonia sensor and the first NOx sensor are not 0, and the absolute value of the difference is ≤ threshold b, it proves that the excessive tail ammonia concentration is caused by the excessive injection of the ammonia injector on the engine. Therefore, the ammonia replacement rate needs to be multiplied by a correction factor to reduce the ammonia injection amount. The total energy is multiplied by (1-ammonia replacement rate) to obtain the partial diesel injection energy, which is divided by the diesel calorific value to obtain the diesel injection amount.

[0070] Patent applications with publication numbers CN117889009A, CN103982308A and CN117646669A only describe the dual-fuel switching and dual-injection post-treatment injection of ammonia fuel engines in detail, but do not clearly state the problem of excessive fuel injection during the dual-fuel mode injection of the engine, resulting in excessive emissions. However, the ammonia fuel engine injection control method proposed in this application reduces the problem of excessive NH3 leakage and inability to be converted by post-treatment during the actual injection process of the ammonia engine through engine fuel injection and coordinated control with post-treatment, and solves the ammonia leakage problem caused by inaccurate injection of existing ammonia fuel engines, thereby meeting the emission regulations of automotive and marine ammonia engines.

[0071] The key points and beneficial effects of this application are as follows:

[0072] 1. This application is based on an ammonia-diesel dual-fuel engine and a dual SCR after-treatment system (not limited to dual-injection SCR, it can also be a DOC+DPF+SCR / ASC National VI after-treatment system) to control the switching of pure diesel to ammonia-diesel dual-fuel mode.

[0073] 2. The switching of ammonia-diesel dual-fuel mode not only includes speed, torque, and engine mode restrictions, but also restrictions based on the after-treatment temperature. In the ammonia-diesel dual-fuel mode, the unburned ammonia is relatively high, the after-treatment temperature is low, the NOx conversion efficiency is low, and the ammonia leakage adsorption capacity is low, thereby preventing ammonia leakage from exceeding the emission limit.

[0074] 3. The ammonia-diesel dual-fuel mode performs closed-loop injection control based on the fuel energy, and calculates the ammonia injection amount and part of the diesel injection amount based on the substitution rate.

[0075] 4. Ammonia-diesel dual-fuel mode Ammonia fuel injection is corrected according to post-processed NH3 emissions to reduce the ammonia replacement rate, thereby preventing ammonia slip.

[0076] 5. Through the logic judgment of the post-treatment ammonia sensor and NOx sensor, the ammonia leakage of the post-treatment system is attributed to the excessive injection of the first ammonia nozzle or the excessive injection of the second ammonia nozzle, so as to accurately control the injection of the original engine and the post-treatment ammonia fuel.

[0077] Based on the same inventive concept, the embodiment of the present application also provides an ammonia fuel engine injection control system based on a post-treatment system for implementing the ammonia fuel engine injection control method involved above. The implementation scheme for solving the problem provided by the device is similar to the implementation scheme recorded in the above method, so the specific limitations in one or more embodiments of the ammonia fuel engine injection control system based on the post-treatment system provided below can refer to the limitations of the ammonia fuel engine injection control method above, and will not be repeated here.

[0078] In an exemplary embodiment, an ammonia fuel engine injection control system based on a post-treatment system is provided, which adopts the above-mentioned ammonia fuel engine injection control method to control the ammonia fuel injection amount when the ammonia fuel engine operates in an ammonia-diesel dual-fuel mode.

[0079] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0080] This article uses specific examples to illustrate the principles and implementation methods of this application. The description of the above embodiments is only used to help understand the method and core ideas of this application. At the same time, for those skilled in the art, according to the ideas of this application, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as limiting this application.

Claims

1. An ammonia fuel engine injection control method, characterized in that: include: When the ammonia fuel engine switches from the pure diesel mode to the ammonia-diesel dual fuel mode, determining the total energy to maintain the pure diesel mode operation; Determining an ammonia fuel injection amount according to an ammonia replacement rate and the total energy under a current operating condition, and performing ammonia fuel injection according to the ammonia fuel injection amount; Obtaining the ammonia concentration of the exhaust gas emitted by the ammonia fuel engine after being treated by the post-treatment system; If the output ammonia concentration is greater than or equal to a first concentration threshold, obtaining an ammonia concentration and a nitrogen oxide concentration at an input end of a mixer in the post-treatment system; If the ammonia concentration and the nitrogen oxide concentration at the input end are both not zero, and the absolute value of the difference between the ammonia concentration and the nitrogen oxide concentration at the input end is less than or equal to the second concentration threshold, the correction factor is used to adjust the ammonia fuel injection amount.

2. The ammonia fuel engine injection control method according to claim 1, characterized in that: Switching from pure diesel mode to ammonia-diesel dual fuel mode requires the following conditions to be met simultaneously: The speed of the ammonia fuel engine is greater than or equal to the lower speed limit and less than or equal to the upper speed limit; The torque of the ammonia fuel engine is greater than or equal to the lower torque limit value, and less than or equal to the upper torque limit value; The ammonia fuel engine operates in a normal operating mode; The normal operating mode at least includes a non-regeneration mode, a heating mode and a desulfurization mode; The temperature of the after-treatment system is greater than or equal to a temperature threshold; the temperature of the after-treatment system is the gas temperature at the input end of the last catalytic converter in the after-treatment system or the gas temperature at the output end of the last catalytic converter in the after-treatment system.

3. The ammonia fuel engine injection control method according to claim 1, characterized in that: Determine the total energy required to maintain diesel-only operation, including: According to the speed and throttle of the ammonia fuel engine, the fuel injection amount is obtained by querying the ignition control curve diagram; Multiply the fuel injection amount by the calorific value to obtain the total energy required to maintain pure diesel mode operation.

4. The ammonia fuel engine injection control method according to claim 1, characterized in that: According to the ammonia replacement rate and the total energy under the current operating conditions, the ammonia fuel injection amount is determined, specifically including: Determine the ammonia replacement rate under current operating conditions corresponding to the calibrated throttle opening and speed of the ammonia fuel engine test bench; Multiplying the total energy by the ammonia replacement rate under the current operating conditions to obtain ammonia injection energy; The ammonia fuel injection amount is obtained by dividing the ammonia injection energy by the ammonia fuel heating value.

5. The ammonia fuel engine injection control method according to claim 1, characterized in that: According to the ammonia replacement rate and the total energy under the current operating condition, an ammonia fuel injection amount is determined, and the ammonia fuel injection is performed according to the ammonia fuel injection amount, and then the method further includes: According to the ammonia substitution rate and the total energy under the current working condition, the diesel injection energy is calculated using the formula C=E×(1-α); wherein C is the diesel injection energy, E is the total energy, and α is the ammonia substitution rate under the current working condition; Divide the diesel injection energy by the diesel calorific value to obtain the diesel injection amount.

6. The ammonia fuel engine injection control method according to claim 1, characterized in that: The amount of ammonia fuel injection is adjusted using correction factors, including: Multiply the ammonia substitution rate under the current operating conditions by the correction factor to obtain a corrected ammonia substitution rate; multiplying the total energy by a corrected ammonia replacement rate to obtain a corrected ammonia injection energy; The corrected ammonia injection energy is divided by the ammonia fuel heating value to obtain the adjusted ammonia fuel injection amount.

7. The ammonia fuel engine injection control method according to claim 1, characterized in that: The post-treatment system is a dual SCR post-treatment system; The dual SCR aftertreatment system includes a mixer, a first ammonia fuel nozzle, a first-stage catalytic converter, a second-stage catalytic converter, a first ammonia sensor and a nitrogen oxide sensor; both the first-stage catalytic converter and the second-stage catalytic converter are SCR / ASC catalytic converters; The input end of the first-stage catalytic converter is connected to the output end of the ammonia engine; the mixer is located between the output end of the first-stage catalytic converter and the input end of the second-stage catalytic converter; A first ammonia fuel nozzle is disposed before the mixer; The first ammonia sensor and the nitrogen oxide sensor are both arranged at the input end of the mixer.

8. The ammonia fuel engine injection control method according to claim 7, characterized in that: If both the ammonia concentration and the nitrogen oxide concentration at the input end are not zero, and the absolute value of the difference between the ammonia concentration and the nitrogen oxide concentration at the input end is less than or equal to the second concentration threshold, the correction factor is used to adjust the ammonia fuel injection amount, specifically including: If both the ammonia concentration measured by the first ammonia sensor and the nitrogen oxide concentration measured by the nitrogen oxide sensor are not zero, and the absolute value of the difference between the ammonia concentration measured by the first ammonia sensor and the nitrogen oxide concentration measured by the nitrogen oxide sensor is less than or equal to a second concentration threshold, a correction factor is used to reduce the injection amount of ammonia fuel injected by a second ammonia fuel nozzle; the second ammonia fuel nozzle is arranged on an intake manifold of an intake system of an ammonia fuel engine; Otherwise, the correction factor is used to reduce the injection amount of the ammonia reductant injected by the first ammonia fuel injector.

9. The ammonia fuel engine injection control method according to claim 7, characterized in that: The dual SCR post-treatment system further includes: a second ammonia sensor, a first temperature sensor, and a second temperature sensor; The first temperature sensor is arranged at the input end of the second-stage catalytic converter, and the second ammonia sensor and the second temperature sensor are both arranged at the output end of the second-stage catalytic converter.

10. An ammonia fuel engine injection control system based on a post-treatment system, characterized in that: The ammonia fuel engine injection control system adopts the ammonia fuel engine injection control method according to any one of claims 1 to 9 to control the ammonia fuel injection amount when the ammonia fuel engine operates in an ammonia-diesel dual-fuel mode.

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