A Selective Catalytic Reduction Correction Method and System

Abstract

The present invention provides a selective catalytic conversion correction method and system, belonging to the field of vehicle energy conservation and emission reduction calculation. The method includes: obtaining the correction amount of the nitrogen oxide sensor according to the HC injection flow rate and the oxygen concentration at the engine outlet, taking the sum of the measured value and the correction amount as the true measured value of this nitrogen oxide sensor, taking the product of the true measured value, the exhaust gas flow rate and the conversion coefficient as the theoretical NH3 injection amount, determining the open-loop set conversion efficiency according to the space velocity and temperature of the selective catalytic conversion device, and taking the product of the open-loop set conversion efficiency, the efficiency correction coefficient based on the temperature of the selective catalytic conversion device, the correction coefficient based on the HC injection amount and the theoretical NH3 injection amount as the final NH3 injection amount; the present invention corrects the NOx sensor by the input HC amount to obtain the correct input NOx concentration, and then corrects the current set efficiency by the HC amount, ensuring the accuracy of NOx control.

Description

Technical Field

[0001] This invention relates to the field of vehicle energy conservation and emission reduction technology, and in particular to a selective catalytic conversion modification method and system. Background Technology

[0002] The statements in this section are merely background information related to the present invention and do not necessarily constitute prior art.

[0003] SCR (Selective Catalytic Reduction) systems can reduce NO x Emissions, the dual SCR system can further improve NO emissions x (Nitrogen oxides) conversion efficiency is beneficial for improving the original NO content of the engine. x This reduces fuel consumption while also lowering thermal management requirements and the risk of crystallization.

[0004] However, the inventors discovered that when using in-cylinder after-injection fuel for active regeneration of the DPF (Diesel Particulate Filter) or temperature control, the pre-stage SCR is exposed to a large amount of HC (hydrocarbons), which affects the SCR conversion efficiency, and the pre-stage NO... x The sensor readings may also be too low, leading to lower efficiency control of the upstream SCR. Summary of the Invention

[0005] To address the shortcomings of existing technologies, this invention provides a selective catalytic conversion correction method and system that corrects NO by adjusting the input HC (hydrocarbon) content and the engine outlet oxygen concentration. x The sensor value, to obtain the correct input NO x The concentration was then adjusted using the HC level to correct the current efficiency setting, ensuring that NO concentration was within acceptable limits. x Accuracy of control.

[0006] To achieve the above objectives, the present invention adopts the following technical solution:

[0007] The first aspect of the present invention provides a method for calibrating a nitrogen oxide sensor based on HC injection volume.

[0008] A method for calibrating a nitrogen oxide sensor based on HC injection volume includes the following steps:

[0009] Acquire the measured values ​​of the nitrogen oxide sensor to be calibrated;

[0010] The correction value for the NOx sensor is obtained based on the HC injection flow rate and the engine outlet oxygen concentration. The sum of the measured value and the correction value is the true measured value of the NOx sensor.

[0011] As a further limitation of the first aspect of the invention, the correction amount for the nitrogen oxide sensor is obtained based on the HC injection flow rate and the engine outlet oxygen concentration, including:

[0012] A correspondence was established between different combinations of HC injection flow rate and engine outlet oxygen concentration and the correction amount of the NOx sensor. Based on the obtained HC injection flow rate and engine outlet oxygen concentration, the correction amount of the NOx sensor was obtained according to the correspondence.

[0013] As a further limitation of the first aspect of the present invention, the nitrogen oxide sensor to be calibrated includes at least a nitrogen oxide sensor located before the pre-selective catalytic conversion device.

[0014] A second aspect of the present invention provides a method for selective catalytic conversion modification.

[0015] A selective catalytic conversion modification method includes the following steps:

[0016] According to the calibration method described in the first aspect of the present invention, the true measured value of the nitrogen oxide sensor is obtained;

[0017] The theoretical NH3 injection quantity is the product of the actual measured value, the exhaust gas flow rate, and the conversion coefficient.

[0018] The open-loop set conversion efficiency is determined based on the space velocity and temperature of the selective catalytic converter. The final NH3 injection quantity is the product of the open-loop set conversion efficiency, the efficiency correction coefficient based on the temperature of the selective catalytic converter, the correction coefficient based on the HC injection quantity, and the theoretical NH3 injection quantity.

[0019] A third aspect of the present invention provides a nitrogen oxide sensor calibration system based on HC injection volume.

[0020] A nitrogen oxide sensor calibration system based on HC injection quantity includes:

[0021] The data acquisition module is configured to acquire the measured values ​​of the nitrogen oxide sensor to be calibrated;

[0022] The sensor calibration module is configured to: obtain the correction amount of the nitrogen oxide sensor based on the HC injection flow rate and the engine outlet oxygen concentration, and use the sum of the measured value and the correction amount as the true measured value of the nitrogen oxide sensor.

[0023] As a further limitation of the third aspect of the present invention, in the sensor calibration module, the correction amount of the nitrogen oxide sensor is obtained based on the HC injection flow rate and the engine outlet oxygen concentration, including:

[0024] A correspondence was established between different combinations of HC injection flow rate and engine outlet oxygen concentration and the correction amount of the NOx sensor. Based on the obtained HC injection flow rate and engine outlet oxygen concentration, the correction amount of the NOx sensor was obtained according to the correspondence.

[0025] As a further limitation of the third aspect of the present invention, in the data acquisition module, the nitrogen oxide sensor to be calibrated includes at least a nitrogen oxide sensor located before the pre-selective catalytic conversion device.

[0026] A fourth aspect of the present invention provides a selective catalytic conversion correction system.

[0027] A selective catalytic conversion correction system, comprising:

[0028] The sensor calibration module is configured to: obtain the true measurement value of the nitrogen oxide sensor according to the calibration method according to the first aspect of the present invention;

[0029] The theoretical NH3 injection quantity calculation module is configured to use the product of the actual measured value, the exhaust gas flow rate, and the conversion coefficient as the theoretical NH3 injection quantity.

[0030] The NH3 actual injection quantity calculation module is configured to: determine the open-loop set conversion efficiency based on the space velocity and temperature of the selective catalytic converter, and use the product of the open-loop set conversion efficiency, the efficiency correction coefficient based on the temperature of the selective catalytic converter, the correction coefficient based on the HC injection quantity, and the theoretical NH3 injection quantity as the final NH3 injection quantity.

[0031] The fifth aspect of the present invention provides a computer-readable storage medium having a program stored thereon that, when executed by a processor, implements the steps in the nitrogen oxide sensor calibration method based on HC injection quantity as described in the first aspect of the present invention; or, when executed by a processor, implements the steps in the selective catalytic conversion correction method as described in the second aspect of the present invention.

[0032] A sixth aspect of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor, wherein the processor executes the program to implement the steps in the nitrogen oxide sensor calibration method based on HC injection quantity as described in the first aspect of the present invention; or, the processor executes the program to implement the steps in the selective catalytic conversion correction method as described in the second aspect of the present invention.

[0033] Compared with the prior art, the beneficial effects of the present invention are:

[0034] 1. This invention innovatively proposes a nitrogen oxide sensor calibration method based on HC injection quantity, which uses HC flow rate and engine outlet oxygen concentration to calibrate NO. xSensor value correction improved NO x The accuracy of the sensor readings.

[0035] 2. This invention innovatively proposes a selective catalytic conversion correction method to obtain the correct NO input through correction. x After determining the concentration, the current efficiency setting is corrected by adjusting the HC level to ensure NO concentration. x Accuracy of control. Attached Figure Description

[0036] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0037] Figure 1 This is a schematic diagram of the dual SCR hardware layout architecture provided in Embodiment 1 of the present invention;

[0038] Figure 2 This is a schematic flowchart of the nitrogen oxide sensor calibration method based on HC injection quantity provided in Embodiment 1 of the present invention;

[0039] Figure 3 This is a schematic diagram illustrating the effect of HC on SCR efficiency provided in Embodiment 1 of the present invention;

[0040] Figure 4 This is a schematic flowchart of the selective catalytic conversion correction method provided in Embodiment 2 of the present invention;

[0041] Figure 5 This is a schematic diagram of the nitrogen oxide sensor calibration system based on HC injection quantity provided in Embodiment 3 of the present invention;

[0042] Figure 6 This is a schematic diagram of the selective catalytic conversion correction system provided in Embodiment 4 of the present invention. Detailed Implementation

[0043] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0044] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0045] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0046] Where there is no conflict, the embodiments and features in the embodiments of the present invention can be combined with each other.

[0047] Example 1:

[0048] The layout diagram of the dual-SCR system used for the China VII emission standards is as follows: Figure 1 As shown, the dual SCR system mainly includes preSCR, Mixer, DOC, DPF, posSCR and ASC;

[0049] Among them, the preSCR is a pre-selective catalytic converter. Urea is injected in front of the preSCR to reduce nitrogen oxides in the exhaust gas. The preSCR is located close to the turbine.

[0050] posSCR stands for Selectively Catalytic Reduction, which injects urea before the SCR to reduce nitrogen oxides in exhaust emissions. The posSCR is located far from the turbine.

[0051] DPF stands for Diesel Particulate Filter, which is used to capture particulate matter in exhaust gas. When the mass of captured particulate matter reaches a certain level, passive or active regeneration is required to restore the DPF's ability to capture particulate matter.

[0052] DOC stands for Diesel Oxide Catalyst, installed before the DPF to oxidize NO in the exhaust gas to NO2, while also increasing the exhaust gas temperature and assisting the normal operation of the DPF and SCR.

[0053] ASC stands for Ammonia Escape Trapper, used to oxidize excess ammonia gas.

[0054] More specifically, particulate oxidation catalysis (DOC) involves coating a honeycomb ceramic support with a noble metal catalyst (such as Pt). Its purpose is to reduce the activation energy of chemical reactions of HC, CO, and SOF in engine exhaust, enabling these substances to undergo oxidation reactions with oxygen in the exhaust at lower temperatures and ultimately be converted into CO2 and H2O. Oxidation catalytic converters do not require regeneration systems or control devices, and are characterized by simple structure and high reliability. They have already been applied to some extent in modern small engines.

[0055] Diesel Particulate Filter (DPF) technology primarily filters and captures particulate matter in engine exhaust through diffusion, deposition, and impaction mechanisms. As exhaust flows through the filter, particulate matter is captured within the filter element, while the cleaner exhaust is released into the atmosphere. Currently, wall-flow honeycomb ceramic filters are widely used, mainly in construction machinery and city buses. They are characterized by simple operation and high filtration efficiency, but they also have issues with filter regeneration and sensitivity to sulfur in fuel.

[0056] The basic working principle of the particulate matter capture system is as follows: When the engine exhaust flows through the oxidation catalyst (DOC), under the temperature conditions of 200℃-600℃, CO and HC are almost completely oxidized into CO2 and H2O, while NO is converted into NO2. After the exhaust comes out of the DOC and enters the particulate filter (DPF), the particulate matter is captured in the filter element of the filter body, and the remaining cleaner exhaust is discharged into the atmosphere. The capture efficiency of the DPF can reach more than 90%.

[0057] NO2 has a strong oxidizing ability on the captured particles. The generated NO2 is used as an oxidant to remove particles from the particulate trap and generate CO2. The NO2 is then reduced to NO, thereby achieving the purpose of removing particles.

[0058] DOC internal reaction principle:

[0059] 2NO + O2 → 2NO2

[0060] 2CO + O2 → 2CO2

[0061] 2CH + O2 → CO2 + H2O

[0062] DPF internal reaction principle:

[0063] C + 2NO₂ → CO₂ + 2NO

[0064] There are two methods for filter regeneration: active regeneration and passive regeneration. Active regeneration refers to using external energy to raise the temperature inside the filter, causing the particulate matter to ignite and burn. When the temperature inside the filter reaches 550°C, the deposited particulate matter will oxidize and burn. If the temperature does not reach 550°C, excessive deposits will clog the filter. In this case, external energy (such as an electric heater, burner, or changes in engine operating conditions) is needed to raise the temperature inside the DPF to oxidize and burn the particulate matter. Passive regeneration refers to using fuel additives or catalysts to lower the ignition temperature of the particulate matter, allowing it to ignite and burn at normal engine exhaust temperatures. Additives (cerium, iron, and strontium) must be added to the fuel in a certain proportion. Too much additive has little effect, but too little will lead to delayed regeneration or an increase in regeneration temperature.

[0065] The basic principle of Selective Catalytic Reduction (SCR) is to inject fuel or add a reducing agent into the exhaust gas. Using a suitable catalyst, the reaction between the reducing agent and NOx is promoted, while the non-selective oxidation reaction between the reducing agent and oxygen is inhibited. Commonly used urea-SCR catalysts include V₂O₅ / W₂O₃ / TiO₂ and metal oxide / zeolite catalysts. Vanadium-based catalysts have high selectivity for NOx and a wide efficient temperature window, as well as high sulfur resistance. However, they are susceptible to poisoning by phosphorus components in lubricating oil and high-temperature failure. Zeolite catalysts have a strong adsorption capacity for NH₃, but at low temperatures, zeolite also has a strong adsorption capacity for HC. HC adsorption affects the low-temperature performance of the catalyst. Furthermore, zeolite has poor hydrothermal stability and sulfur resistance, thus limiting its practical application and requiring the use of low-sulfur fuels.

[0066] Sulfur oxides in copper-based SCRs form sulfates, reducing catalyst active sites, clogging pores, and decreasing the SCR's NOx conversion efficiency. Therefore, once a certain amount of sulfur oxides is captured within the SCR, desulfurization is necessary. Sulfur poisoning has two mechanisms: the formation of (NH4)SO4, etc., reducing SCR catalyst active sites and clogging pores, thereby reducing NOx conversion efficiency. x Conversion efficiency; SO2 and SO3 versus NO x Competitive adsorption reduces NO x Adsorption.

[0067] The reaction principle of SCR technology:

[0068] Urea is hydrolyzed into ammonia (urea injection system):

[0069] (NH2)2CO + H2O → 2NH3 + CO2

[0070] SCR post-processing reaction (SCR catalytic converter):

[0071] NO + NO₂ + 2NH₃ → 2N₂ + 3H₂O

[0072] 4NO + O2 + 4NH3 → 4N2 + 6H2O

[0073] 2NO2 + O2 + 4NH3 → 3N2 + 6H2O

[0074] In SCR, the actual reducing agent participating in the selective catalytic reduction reaction is ammonia (NH3). However, due to the high corrosiveness of ammonia, liquid ammonia and ammonia water present difficulties in storage and transportation, and therefore cannot be directly used in vehicle-mounted SCR systems. Currently, urea aqueous solution is generally used as the reducing agent. Furthermore, since a 32.5% urea aqueous solution has the lowest freezing point of -11℃ compared to other concentrations of urea aqueous solution, it is internationally widely used as the standard reducing agent for SCR and named AdBlue.

[0075] like Figure 2 The test results show that NO is placed before and after the SCR. x Sensors and emission devices for measuring NO x Changes in conversion efficiency. First, urea is not sprayed until the upstream and downstream sensor signals stabilize. Then, at point S0, urea is sprayed at a fixed injection rate. Downstream NO... x The value begins to decrease until it stabilizes; at point S1, HC is injected at a fixed flow rate, and upstream NO... x The sensor measurement is too low, and the SCR NO is too low. x Conversion efficiency decreased; HC spraying was stopped at point S2, and SCR NO decreased. x As conversion efficiency gradually recovers, based on the experimental results, the following control strategy is designed:

[0076] like Figure 3 shown, NO x Sensor corrections include: obtaining NO based on HC injection flow rate and engine outlet oxygen concentration. x Correction amount, then add NO x Sensor measurements yield NO x Final correction amount.

[0077] In this embodiment, HC in NO x The sensor is oxidized, consuming some oxygen and causing measurement errors. Therefore, a corrected MAP table (a two-dimensional table, where the x-axis represents the HC flow rate, the y-axis represents the engine outlet oxygen concentration, and the z-axis represents NO) is calibrated based on the HC flow rate and engine outlet oxygen concentration. x Correction amount), indicate the correction amount, NO x 1 / 2 / 3 are all the same, because NO x The 2 / 3 position is basically unaffected by HC, so it doesn't need to be repaired.

[0078] Example 2:

[0079] like Figure 4 As shown, Embodiment 2 of the present invention provides a selective catalytic conversion correction method, comprising the following processes:

[0080] NO x Sensor corrections include: obtaining NO based on HC injection flow rate and engine outlet oxygen concentration. x Correction amount, then add NO x Sensor measurements yield NO x The final correction amount, based on the current exhaust gas flow rate and conversion coefficient, yields the theoretical NH3 injection quantity, including:

[0081] NH3 (mg / s) = NO x (ppm) * exhaust gas flow rate (kg / h) * 0.0001628;

[0082] SCR control correction includes: determining the open-loop set conversion efficiency by looking up the MAP table based on SCR air velocity and temperature, multiplying it by an efficiency correction factor based on SCR temperature, multiplying it by a correction factor based on HC injection quantity to obtain the final set correction efficiency, and multiplying the theoretical NH3 injection quantity by the set correction efficiency to obtain the NH3 injection quantity.

[0083] In this embodiment, a set conversion efficiency MAP (i.e., a two-dimensional table, with SCR space velocity on the x-axis, SCR temperature on the y-axis, and set conversion efficiency on the z-axis) is calibrated based on SCR space velocity and temperature, representing the required conversion efficiency without considering the effects of oxidation and HC at the current space velocity and temperature.

[0084] In this embodiment, the efficiency correction coefficient for SCR temperature is obtained as follows: At different SCR temperatures, the amount of NH3 oxidized by the catalyst is different. When the SCR temperature exceeds 350°C, part of the injected NH3 will be oxidized, resulting in the actual efficiency being lower than the required efficiency. Therefore, a one-dimensional table is calibrated based on the SCR temperature (x is the SCR temperature, and the output y is the correction coefficient) to determine the correction coefficient. This part is increased by placing the SCR temperature at different temperatures on the test bench. If the efficiency is set to 80%, 80% of urea is injected first. If it is not satisfied, the urea injection is increased until the set efficiency is met. The efficiency correction coefficient for SCR temperature is obtained by dividing the actual injection by the theoretical injection of 80%.

[0085] The method for obtaining the correction coefficient based on HC injection quantity is similar. Under different HC injection conditions, the set efficiency is met, the ratio of actual injection to theoretical injection is calculated, and the correction coefficient based on HC injection quantity is obtained.

[0086] Example 3:

[0087] like Figure 5 As shown, Embodiment 3 of the present invention provides a nitrogen oxide sensor calibration system based on HC injection quantity, comprising:

[0088] The data acquisition module is configured to acquire the measured values ​​of the nitrogen oxide sensor to be calibrated;

[0089] The sensor calibration module is configured to: obtain the correction amount of the nitrogen oxide sensor based on the HC injection flow rate and the engine outlet oxygen concentration, and use the sum of the measured value and the correction amount as the true measured value of the nitrogen oxide sensor.

[0090] In the sensor calibration module, the correction amount for the nitrogen oxide sensor is obtained based on the HC injection flow rate and the engine outlet oxygen concentration, including:

[0091] A correspondence was established between different combinations of HC injection flow rate and engine outlet oxygen concentration and the correction amount of the NOx sensor. Based on the obtained HC injection flow rate and engine outlet oxygen concentration, the correction amount of the NOx sensor was obtained according to the correspondence.

[0092] In the data acquisition module, the nitrogen oxide sensor to be calibrated includes at least a nitrogen oxide sensor located before the pre-selective catalytic converter.

[0093] The specific working methods of each module are the same as the nitrogen oxide sensor calibration method based on HC injection volume provided in Example 1, and will not be repeated here.

[0094] Example 4:

[0095] like Figure 6 As shown, Embodiment 4 of the present invention provides a selective catalytic conversion correction system, comprising:

[0096] The sensor calibration module is configured to obtain the true measurement value of the nitrogen oxide sensor according to the calibration method described in Embodiment 1 of the present invention.

[0097] The theoretical NH3 injection quantity calculation module is configured to use the product of the actual measured value, the exhaust gas flow rate, and the conversion coefficient as the theoretical NH3 injection quantity.

[0098] The NH3 actual injection quantity calculation module is configured to: determine the open-loop set conversion efficiency based on the space velocity and temperature of the selective catalytic converter, and use the product of the open-loop set conversion efficiency, the efficiency correction coefficient based on the temperature of the selective catalytic converter, the correction coefficient based on the HC injection quantity, and the theoretical NH3 injection quantity as the final NH3 injection quantity.

[0099] The specific working methods of each module are the same as those of the selective catalytic conversion correction method provided in Example 2, and will not be repeated here.

[0100] Example 5:

[0101] Embodiment 5 of the present invention provides a computer-readable storage medium having a program stored thereon. When executed by a processor, the program implements the steps in the nitrogen oxide sensor calibration method based on HC injection quantity as described in Embodiment 1 of the present invention; or, when executed by a processor, the program implements the steps in the selective catalytic conversion correction method as described in Embodiment 2 of the present invention.

[0102] Example 6:

[0103] Embodiment 6 of the present invention provides an electronic device, including a memory, a processor, and a program stored in the memory and executable on the processor. When the processor executes the program, it implements the steps in the nitrogen oxide sensor calibration method based on HC injection quantity as described in Embodiment 1 of the present invention; or, when the processor executes the program, it implements the steps in the selective catalytic conversion correction method as described in Embodiment 2 of the present invention.

[0104] Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of hardware embodiments, software embodiments, or embodiments combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage and optical storage) containing computer-usable program code.

[0105] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0106] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1The function specified in one or more boxes.

[0107] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0108] Those skilled in the art will understand that all or part of the processes in the above embodiments can be implemented by a computer program instructing related hardware. The program can be stored in a computer-readable storage medium, and when executed, it can include the processes of the embodiments of the above methods. The storage medium can be a magnetic disk, optical disk, read-only memory (ROM), or random access memory (RAM), etc.

[0109] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A selective catalytic conversion modification method, characterized in that, Includes the following steps: The true measured value of the nitrogen oxide sensor is obtained based on the nitrogen oxide sensor calibration method based on HC injection volume; The theoretical NH3 injection quantity is the product of the actual measured value, the exhaust gas flow rate, and the conversion coefficient. The open-loop set conversion efficiency is determined based on the space velocity and temperature of the selective catalytic converter. The final NH3 injection amount is the product of the open-loop set conversion efficiency, the efficiency correction coefficient based on the temperature of the selective catalytic converter, the correction coefficient based on the HC injection amount, and the theoretical NH3 injection amount. The nitrogen oxide sensor calibration method based on HC injection volume includes: Acquire the measured values ​​of the nitrogen oxide sensor to be calibrated; The correction value of the nitrogen oxide sensor is obtained based on the HC injection flow rate and the oxygen concentration at the engine outlet. The sum of the measured value and the correction value is the true measured value of the nitrogen oxide sensor. The correction amount for the nitrogen oxide sensor is obtained based on the HC injection flow rate and the engine outlet oxygen concentration, including: A correspondence was established between different combinations of HC injection flow rate and engine outlet oxygen concentration and the correction amount of the NOx sensor. Based on the obtained HC injection flow rate and engine outlet oxygen concentration, the correction amount of the NOx sensor was obtained according to the correspondence. The nitrogen oxide sensors to be calibrated include at least the nitrogen oxide sensors located before the pre-selective catalytic conversion unit.

2. A selective catalytic conversion correction system, characterized in that, include: The sensor calibration module is configured to obtain the true measured value of the nitrogen oxide sensor according to the nitrogen oxide sensor calibration method based on HC injection quantity; The theoretical NH3 injection quantity calculation module is configured to use the product of the actual measured value, the exhaust gas flow rate, and the conversion coefficient as the theoretical NH3 injection quantity. The NH3 actual injection quantity calculation module is configured to: determine the open-loop set conversion efficiency based on the space velocity and temperature of the selective catalytic converter, and use the product of the open-loop set conversion efficiency, the efficiency correction coefficient based on the temperature of the selective catalytic converter, the correction coefficient based on the HC injection quantity, and the theoretical NH3 injection quantity as the final NH3 injection quantity. The nitrogen oxide sensor calibration method based on HC injection volume includes: Acquire the measured values ​​of the nitrogen oxide sensor to be calibrated; The correction value of the nitrogen oxide sensor is obtained based on the HC injection flow rate and the oxygen concentration at the engine outlet. The sum of the measured value and the correction value is the true measured value of the nitrogen oxide sensor. The correction amount for the nitrogen oxide sensor is obtained based on the HC injection flow rate and the engine outlet oxygen concentration, including: A correspondence was established between different combinations of HC injection flow rate and engine outlet oxygen concentration and the correction amount of the NOx sensor. Based on the obtained HC injection flow rate and engine outlet oxygen concentration, the correction amount of the NOx sensor was obtained according to the correspondence. The nitrogen oxide sensors to be calibrated include at least the nitrogen oxide sensors located before the pre-selective catalytic conversion unit.

3. A computer-readable storage medium having a program stored thereon, characterized in that, When the program is executed by the processor, it implements the steps in the selective catalytic conversion modification method as described in claim 1.

4. An electronic device comprising a memory, a processor, and a program stored in the memory and executable on the processor, characterized in that, When the processor executes the program, it implements the steps in the selective catalytic conversion correction method as described in claim 1.

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