Ammonia fuel engine injection control method and system

Abstract

The present application discloses a method and system for ammonia fuel engine injection control, which relates to the field of ammonia fuel engines. The method includes: when the ammonia fuel engine switches from the pure diesel mode to the ammonia-diesel dual-fuel mode, determining the total energy required to maintain operation in the pure diesel mode; determining the ammonia fuel injection quantity according to the ammonia substitution rate and the total energy under the current working conditions, and performing ammonia fuel injection according to the ammonia fuel injection quantity; obtaining the ammonia concentration of the exhaust gas emitted by the ammonia fuel engine after being treated by the aftertreatment system; if the output ammonia concentration is greater than or equal to the first concentration threshold, obtaining the ammonia concentration and the nitrogen oxide concentration at the input end of the mixer in the aftertreatment system; 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, adjusting the ammonia fuel injection quantity by using a correction factor. The present application can accurately control the injection of ammonia fuel and prevent ammonia leakage and excessive emissions.

Description

Technical Field

[0001] The present application relates to the field of ammonia fuel engines, and particularly to a method and system for controlling the injection of ammonia fuel engines. Background Art

[0002] At present, the research and development of new low-carbon and zero-carbon alternative fuels and their engine technologies is extremely urgent. The development of ammonia engines is a relatively ideal route at present. However, most of the existing injection controls for ammonia fuel engines do not consider the emission control in actual operation. However, ammonia fuel engines have problems of 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 a method and system for controlling the injection of ammonia fuel engines, which can accurately control the injection of ammonia fuel and prevent ammonia leakage and excessive emissions.

[0004] To achieve the above purpose, the present application provides the following solutions:

[0005] In the first aspect, the present application provides a method for controlling the injection of an ammonia fuel engine, including: when the ammonia fuel engine switches from the pure diesel mode to the ammonia-diesel dual-fuel mode, determining the total energy required to maintain the operation in the pure diesel mode; determining the ammonia fuel injection amount according to the ammonia substitution rate and the total energy under the current working condition, and injecting ammonia fuel according to the ammonia fuel injection amount; obtaining the ammonia concentration of the exhaust gas emitted by the ammonia fuel engine after being processed by the post-treatment system; if the output ammonia concentration is greater than or equal to the first concentration threshold, obtaining the ammonia concentration and the nitrogen oxide concentration at the input end of the mixer in the post-treatment system; 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, adjusting the ammonia fuel injection amount using a correction factor.

[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 uses the above-mentioned ammonia fuel engine injection control method to control the ammonia fuel injection amount when the ammonia fuel engine operates in the ammonia-diesel dual-fuel mode.

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

[0008] The present application provides a method and system for controlling the injection of an ammonia fuel engine. In the ammonia-diesel dual-fuel mode, according to the ammonia concentration output by the post-treatment system and the ammonia concentration and nitrogen oxide concentration at the input end of the mixer in the post-treatment system, when it is determined that the ammonia concentration in the tail gas of the ammonia fuel engine is too high, the ammonia fuel injection amount is adjusted using a correction factor, accurately controlling the injection of ammonia fuel, and realizing the closed-loop injection control of ammonia fuel, effectively preventing ammonia leakage and excessive emissions. Description of the Drawings

[0009] To more clearly illustrate the technical solutions in the embodiments of the present application or the related art, the following will briefly introduce the drawings required for use in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present application. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0010] Figure 1 It is a schematic flowchart of a method for controlling the injection of an ammonia fuel engine provided by an embodiment of the present application;

[0011] Figure 2 It is a schematic diagram of the switching logic between pure diesel / ammonia-diesel dual-fuel modes provided by another embodiment of the present application;

[0012] Figure 3 It is a schematic diagram of the principle of a method for controlling the injection of an ammonia fuel engine provided by an embodiment of the present application;

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

[0014] Figure 5 It is a schematic diagram of the principle of controlling the injection of an ammonia fuel engine based on a dual-SCR aftertreatment system provided by an embodiment of the present application. Specific Embodiments

[0015] The following will clearly and completely describe the technical solutions in the embodiments of the present application with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, rather than all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0016] To make the above objects, features, and advantages of the present application more obvious and understandable, the present application will be further described in detail below with reference to the drawings and specific embodiments.

[0017] The following are the terms used in the present application:

[0018] NH 3 : represents ammonia gas, and NOx: represents nitrogen oxides.

[0019] SCR: Selective Catalytic Reduction, a selective catalytic reduction catalyst, which converts NOx in the exhaust gas when spraying NH 3 .

[0020] ASC: Ammonia Slip Catalyst, an ammonia oxidation catalyst, is used to adsorb and convert NH in the exhaust gas. 3 However, its adsorption capacity is limited.

[0021] Pure diesel mode: The main fuel of the engine is diesel, and ammonia fuel injection is not carried out 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, as Figure 1 shown, an ammonia fuel engine injection control method is provided, including the following steps 101 to step 105. Among them:

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

[0025] Step 102: According to the ammonia substitution rate under the current working conditions and the total energy, determine the ammonia fuel injection amount, and inject ammonia fuel according to the ammonia fuel injection amount.

[0026] Step 103: Obtain 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, obtain the ammonia concentration and nitrogen oxide concentration at the input end of the mixer in the post-treatment system.

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

[0029] Implementing the above steps 101 to 105, in the ammonia-diesel dual-fuel mode, according to the ammonia fuel concentration output by the post-treatment system and the ammonia fuel concentration and nitrogen oxide concentration at the input end, when it is determined that the ammonia concentration in the tail gas of the ammonia fuel engine is too high, the ammonia fuel injection amount is adjusted using a correction factor, accurately controlling the ammonia fuel injection, and realizing the closed-loop injection control of ammonia fuel, effectively preventing ammonia leakage and excessive emissions.

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

[0031] In another exemplary embodiment of the present application, the above step 101 needs to simultaneously meet the following conditions when switching from the pure diesel mode to the ammonia-diesel dual-fuel mode:

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

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

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

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

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

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

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

[0039] ③ The engine is in a normal operation mode: non-regenerative, heating, and desulfurization modes, etc., to prevent the process from entering the dual-fuel mode and causing excessive NH 3 emissions.

[0040] ④ When the engine switches to the ammonia-diesel dual-fuel mode, a large amount of unburned ammonia is likely to be generated due to incomplete combustion. Taking the dual-SCR after-treatment system as an example, if the after-treatment temperature is low, the ability of the SCR catalyst to adsorb NH 3 and NOx is low, resulting in easy excessive NH 3 emissions. Therefore, the temperatures of the two-stage SCR in the after-treatment should be greater than a certain temperature to ensure that the emissions do not exceed the regulatory limits in the dual-fuel mode.

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

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

[0043] Step 201: According to the rotational speed and throttle of the ammonia fuel engine, obtain the fuel injection quantity by querying the ignition control curve graph.

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

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

[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 ammonia fuel injection plus the energy of partial diesel injection is equal to the total energy in the pure diesel mode.

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

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

[0049] During the ammonia substitution rate calibration process, the explosion pressure and the maximum exhaust gas temperature need to be monitored.

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

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

[0052] After obtaining the ammonia fuel injection quantity, ammonia fuel injection is carried out 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. Wherein:

[0054] Step 401: According to the ammonia substitution rate under the current operating conditions and the total energy, use the formula C = E×(1 - α) to calculate the diesel injection energy; where 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 calorific value of diesel to obtain the diesel injection quantity.

[0056] In another exemplary embodiment of the present application, the above step 105 adjusts the ammonia fuel injection quantity using a correction factor, 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 the corrected ammonia substitution rate.

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

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

[0060] The principle of the ammonia fuel engine injection control method is as Figure 3 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 may 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; 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; the first ammonia fuel nozzle is arranged in front of the mixer; both the first ammonia sensor and the nitrogen oxide sensor are 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 arranged at the input end of the second-stage catalytic converter, and both the second ammonia fuel sensor and the second temperature sensor are arranged 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 further arranged 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 is a schematic diagram of an ammonia engine and a dual SCR post-treatment system. Figure 4The intake system of the medium ammonia engine is in sequence 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 in-cylinder direct injection combustion improver can be and is not limited to diesel, hydrogen, and dimethyl ether. The exhaust gas after cylinder combustion is discharged after doing work through a turbine. The exhaust gas passes through the first-stage SCR / ASC. No reductant injection device is provided in front of the first-stage SCR / ASC. Only the unburned ammonia fuel in the exhaust gas is relied on to convert NOx. A mixer is connected after the first-stage SCR / ASC. The first ammonia fuel nozzle is installed in front of the mixer. Based on the measurements of the NOx sensor, ammonia sensor, and temperature sensor between the two-stage SCRs as input boundaries, ammonia fuel injection is carried out 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 aftertreatment system is a dual-SCR aftertreatment system, the above step 105 can be replaced by the following steps 601 to 602:

[0066] Step 601: If both the ammonia fuel concentration measured by the first ammonia fuel 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 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, then the ammonia fuel injection amount injected by the second ammonia fuel nozzle is reduced by using a correction factor.

[0067] Step 602: Otherwise, the ammonia reductant injection amount injected by the first ammonia fuel nozzle is reduced by using a correction factor.

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

[0069] Perform the judgment of the dual-fuel mode jump condition. If it is satisfied, look up the MAP through the engine speed and throttle to obtain the fuel injection quantity corresponding to the working condition in the pure diesel mode. Multiply the diesel injection quantity by the calorific value to obtain the total energy required to maintain the operation of this working condition. According to the law of conservation of energy, after entering the dual-fuel mode, the energy provided by ammonia fuel injection plus the energy of partial diesel injection is equal to the total energy in the pure diesel mode. Calibrate the ammonia substitution rate corresponding to the throttle opening and engine speed under the working condition through the engine bench (monitor the explosion pressure and the maximum exhaust temperature during the calibration process of the ammonia substitution rate). Multiply the total energy by the ammonia substitution rate to obtain the ammonia injection energy. Divide the ammonia injection energy by the calorific value of ammonia fuel to obtain the ammonia nozzle injection quantity, and then perform ammonia fuel injection according to the injection pressure and pulse width. The dual-fuel mode needs to consider the ability of the aftertreatment to convert the unburned ammonia, and perform transient correction of the ammonia substitution rate according to the measured values of the NOx and NH 3 sensor measurements. When the second NH 3 sensor is greater than or equal to the threshold value a, it indicates that the aftertreatment system faces the risk of NH 3 over-emission, but it is necessary to determine whether the ammonia injection exceeds the standard. Analyze which injector, the first ammonia nozzle or the second ammonia nozzle, causes excessive injection of NH 3 leakage. If both the first ammonia sensor and the first NOx sensor are not zero, and the absolute value of the difference ≤ the threshold value b, it proves that the excessive ammonia concentration in the tail gas is caused by excessive injection of the ammonia injector on the engine. Therefore, the ammonia substitution rate needs to be multiplied by a correction factor to reduce the ammonia injection quantity. Multiply the total energy by (1 - ammonia substitution rate) to obtain the partial diesel injection energy, and divide it by the calorific value of diesel to obtain the diesel injection quantity.

[0070] Patent applications with publication numbers CN117889009A, CN103982308A, and CN117646669A only describe in detail the dual-fuel switching of ammonia fuel engines and the post-treatment injection of dual injection, and do not clearly describe the problem of excessive fuel injection during the injection process of the engine dual-fuel mode resulting in emissions exceeding the limit value. However, an ammonia fuel engine injection control method proposed in this application, through the coordinated control of engine fuel injection and post-treatment, reduces the problem of excessive NH 3 leakage during the actual injection process of ammonia engines and the inability of the post-treatment to convert it, solves the problem of ammonia leakage caused by inaccurate injection of existing ammonia fuel engines, thus meeting the emission regulations of vehicle ammonia engines 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 post-treatment system (not limited to dual-injection SCR, it can also be a DOC+DPF+SCR / ASC national VI post-treatment system) to control the switching from pure diesel to ammonia-diesel dual-fuel mode.

[0073] 2. The ammonia-diesel dual-fuel mode switching not only includes speed, torque, and engine mode limitations, but also is restricted according to the aftertreatment temperature. In the ammonia-diesel dual-fuel mode, the unburned ammonia is relatively high, the aftertreatment temperature is low, the NOx conversion efficiency is low, and the ammonia leakage adsorption capacity is low, thus preventing ammonia leakage from exceeding the emission limit.

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

[0075] 4. The ammonia fuel injection in the ammonia-diesel dual-fuel mode is corrected according to the aftertreatment NH 3 emission, reducing the ammonia substitution rate, thus preventing ammonia leakage.

[0076] 5. Through the logical judgment of the aftertreatment ammonia sensor and NOx sensor, it is attributed to whether the first ammonia nozzle injects excessively or the second ammonia nozzle injects excessively for the ammonia leakage in the aftertreatment system, so as to precisely control the ammonia fuel injection of the original engine and the aftertreatment.

[0077] Based on the same inventive concept, the embodiment of the present application also provides an aftertreatment system-based ammonia fuel engine injection control system for implementing the above-mentioned ammonia fuel engine injection control method. The solution provided by this device to solve the problem is similar to the solution described in the above method. Therefore, the specific limitations in one or more of the following embodiments of the aftertreatment system-based ammonia fuel engine injection control system can refer to the limitations on the ammonia fuel engine injection control method in the above text, and will not be repeated here.

[0078] In an exemplary embodiment, an aftertreatment system-based ammonia fuel engine injection control system is provided. This 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 the ammonia-diesel dual-fuel mode.

[0079] The technical features of the above embodiments can be combined arbitrarily. For the sake of brief description, 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, it should be considered as the scope recorded in this specification.

[0080] Specific examples are used in this article to elaborate on the principles and implementation manners of the present application. The description of the above embodiments is only used to help understand the method and its core idea of the present application; at the same time, for those of ordinary skill in the art, according to the idea of the present application, there will be changes in the specific implementation manners and application scopes. In summary, the content of this specification should not be construed as a limitation to the present 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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