Urea injection amount control method and device and electronic equipment

Abstract

The invention provides a urea injection amount control method and device and electronic equipment, and relates to the technical field of automobile exhaust emission aftertreatment. The method is applied to a two-stage SCR aftertreatment system. An iron-based catalyst is adopted at the front end of a rear-stage SCR in the two-stage SCR aftertreatment system, a copper-based catalyst is adopted at the rear end of the rear-stage SCR, and the method comprises the steps that a first internal ammonia storage predicted value of the rear-stage SCR is determined based on an iron-based catalyst kinetic model and a copper-based catalyst kinetic model of the rear-stage SCR; based on the first internal ammonia storage predicted value and an internal ammonia storage set value of the post-stage SCR, determining a first ammonia storage corrected urea injection amount of the post-stage SCR; and determining the total urea injection amount of the post-stage SCR based on the feed-forward urea injection amount of the post-stage SCR and the first ammonia storage correction urea injection amount. The urea spraying amount can be accurately controlled, and N2O emission of a post-treatment system is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of automotive exhaust after-treatment, and particularly relates to a method, device and electronic device for controlling urea injection amount. Background Art

[0002] N2O is a potent greenhouse gas with a global warming potential 298 times that of CO2 and is destructive to the ozone layer. Currently, diesel engine after-treatment systems mainly reduce nitrogen oxide (NOx) emissions through SCR (selectively catalytic reduction), but N2O is also generated during the SCR reaction process. As diesel vehicle emission regulations become stricter on non-CO2 greenhouse gases, new restrictions on N2O emissions have been added, so how to inhibit N2O generation in the after-treatment system faces a severe challenge. Summary of the Invention

[0003] In view of this, embodiments of the present invention are committed to providing a method, device and electronic device for controlling urea injection amount to inhibit the generation of N2O in the after-treatment system.

[0004] The first aspect of the present invention provides a method for controlling urea injection amount, which is applied to a two-stage SCR after-treatment system; in the two-stage SCR after-treatment system, an iron-based catalyst is used at the front end of the rear-stage SCR, and a copper-based catalyst is used at the rear end; the method includes: Based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the rear-stage SCR, determine a first predicted value of the internal ammonia storage of the rear-stage SCR; both the kinetic model of the iron-based catalyst and the kinetic model of the copper-based catalyst include ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction and N2O generation reaction; Based on the first predicted value of the internal ammonia storage and the set value of the internal ammonia storage of the rear-stage SCR, determine a first ammonia storage correction urea injection amount for the rear-stage SCR; Based on the feed-forward urea injection amount of the rear-stage SCR and the first ammonia storage correction urea injection amount, determine the total urea injection amount of the rear-stage SCR.

[0005] In some embodiments, the determining the first predicted value of the internal ammonia storage of the rear-stage SCR based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the rear-stage SCR includes: Based on the kinetic models of the iron-based catalyst and the copper-based catalyst, determine the first predicted value of the internal ammonia storage and a first predicted value of the NOx concentration downstream of the rear-stage SCR; Determining the total urea injection amount of the post-stage SCR based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage correction urea injection amount includes: Determining the model conversion efficiency of the post-stage SCR based on the first NOx concentration predicted value and the actual value of the first NOx concentration upstream of the post-stage SCR; Determining the model feedforward urea injection amount of the post-stage SCR according to the set conversion efficiency and the model conversion efficiency of the post-stage SCR; Determining the sum result of the feedforward urea injection amount of the post-stage SCR, the first ammonia storage correction urea injection amount, and the model feedforward urea injection amount, and determining the total urea injection amount of the post-stage SCR based on the sum result.

[0006] As an example, the determining the model feedforward urea injection amount of the post-stage SCR according to the set conversion efficiency and the model conversion efficiency of the post-stage SCR includes: Determining the first difference between the set conversion efficiency and the model conversion efficiency; Determining the model feedforward urea injection amount based on the first difference.

[0007] In some embodiments, the determining the total urea injection amount of the post-stage SCR based on the sum result includes: Determining a closed-loop correction factor based on the model conversion efficiency and the actual conversion efficiency of the post-stage SCR; Determining the product of the sum result and the closed-loop correction factor as the total urea injection amount of the post-stage SCR.

[0008] As a possible implementation manner, the determining the first internal ammonia storage predicted value of the post-stage SCR based on the iron-based catalyst kinetic model and the copper-based catalyst kinetic model of the post-stage SCR includes: Inputting the inlet temperature of the post-stage SCR, the urea injection amount at the previous moment, the actual value of the first NOx concentration upstream of the post-stage SCR, and the exhaust gas flow rate into the iron-based catalyst kinetic model to obtain the predicted value of the second NOx concentration downstream of the iron-based catalyst, the predicted value of the NH3 concentration, the predicted value of the temperature, and the predicted value of the iron-based internal ammonia storage output by the iron-based catalyst kinetic model; Inputting the predicted value of the second NOx concentration, the predicted value of the NH3 concentration, the predicted value of the temperature, and the exhaust gas flow rate into the copper-based catalyst kinetic model to obtain the predicted value of the copper-based internal ammonia storage output by the copper-based catalyst kinetic model; Determining the sum of the predicted value of the iron-based internal ammonia storage and the predicted value of the copper-based internal ammonia storage as the first internal ammonia storage predicted value.

[0009] In some embodiments, the method further includes: Based on the kinetic model of the front-stage SCR in the two-stage SCR aftertreatment system, determining a predicted value of the second internal ammonia storage of the front-stage SCR; wherein, the kinetic model of the front-stage SCR includes ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; Based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the front-stage SCR, determining a second ammonia storage correction urea injection amount for the front-stage SCR; Based on the feedforward urea injection amount of the front-stage SCR and the second ammonia storage correction urea injection amount, determining the total urea injection amount of the front-stage SCR.

[0010] In some embodiments, the determining the predicted value of the second internal ammonia storage of the front-stage SCR based on the kinetic model of the front-stage SCR in the two-stage SCR aftertreatment system includes: Based on the kinetic model of the front-stage SCR, determining the predicted value of the second internal ammonia storage and the predicted value of the third NOx concentration downstream of the front-stage SCR; The determining the total urea injection amount of the front-stage SCR based on the feedforward urea injection amount of the front-stage SCR and the second ammonia storage correction urea injection amount includes: Based on the actual value of the first NOx concentration upstream of the rear-stage SCR and the predicted value of the third NOx concentration, determining a closed-loop correction urea injection amount for the front-stage SCR; Adding the feedforward urea injection amount, the second ammonia storage correction urea injection amount, and the closed-loop correction urea injection amount of the front-stage SCR, and determining the sum as the total urea injection amount of the front-stage SCR.

[0011] A second aspect of the present invention provides a urea injection amount control device, which is applied to a two-stage SCR aftertreatment system; a front end of the rear-stage SCR in the two-stage SCR aftertreatment system uses an iron-based catalyst, and a rear end uses a copper-based catalyst; the device includes: A first determination module, configured to determine a predicted value of the first internal ammonia storage of the rear-stage SCR based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the rear-stage SCR; both the kinetic model of the iron-based catalyst and the kinetic model of the copper-based catalyst include ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; A second determination module, configured to determine a first ammonia storage correction urea injection amount for the rear-stage SCR based on the predicted value of the first internal ammonia storage and the set value of the internal ammonia storage of the rear-stage SCR; A third determination module, configured to determine the total urea injection amount of the post-stage SCR based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage corrected urea injection amount.

[0012] A third aspect of the present invention provides an electronic device, including a processor and a memory storing a computer program, where when the processor executes the computer program, the urea injection amount control method described in the first aspect above is implemented.

[0013] A fourth aspect of the present invention provides a computer-readable storage medium, on which a computer program is stored, and the computer program can be executed by a processor to implement the urea injection amount control method described in the first aspect above.

[0014] According to the urea injection amount control method, device and electronic device of the present invention, a ferrous-based catalyst is used at the front end of the post-stage SCR in the dual-stage SCR post-treatment system, and a copper-based catalyst is used at the rear end. By determining the first internal ammonia storage prediction value of the post-stage SCR based on the kinetic models of the ferrous-based catalyst and the copper-based catalyst of the post-stage SCR; determining the first ammonia storage corrected urea injection amount of the post-stage SCR based on the first internal ammonia storage prediction value and the internal ammonia storage set value of the post-stage SCR; determining the total urea injection amount of the post-stage SCR based on the feedforward urea injection amount and the first ammonia storage corrected urea injection amount of the post-stage SCR. The present invention combines a ferrous-based catalyst and a copper-based catalyst in the post-stage SCR, and determines the ammonia storage corrected urea injection amount based on the internal ammonia storage prediction value determined by the kinetic models of the ferrous-based catalyst and the copper-based catalyst, so as to determine the total urea injection amount of the post-stage SCR, thereby accurately controlling the urea injection amount and reducing the N2O emission of the post-treatment system. Description of the Drawings

[0015] The drawings here are incorporated into the specification and form a part of this specification, showing embodiments consistent with the present invention, and are used together with the specification to explain the principles of the present invention.

[0016] Figure 1 It is a schematic structural diagram of the dual-stage SCR post-treatment system in the embodiments of the present invention.

[0017] Figure 2 It is a schematic flowchart of a urea injection control method provided by the embodiments of the present invention.

[0018] Figure 3 It is a schematic flowchart of another urea injection amount control method provided by the embodiments of the present invention.

[0019] Figure 4 It is a schematic flowchart of yet another urea injection amount control method provided by the embodiments of the present invention.

[0020] Figure 5It is an example diagram of the urea injection amount control logic for the post-stage SCR in the embodiments of the present invention.

[0021] Figure 6 It is a schematic flowchart of another urea injection amount control method provided by the embodiments of the present invention.

[0022] Figure 7 It is a schematic flowchart of another urea injection amount control method provided by the embodiments of the present invention.

[0023] Figure 8 It is an example diagram of the urea injection amount control logic for the pre-stage SCR in the embodiments of the present invention.

[0024] Figure 9 It is a schematic structural diagram of a urea injection amount control device provided by the embodiments of the present invention.

[0025] Figure 10 It is a schematic structural diagram of an electronic device provided by the embodiments of the present invention. Detailed implementation manners

[0026] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0027] For the convenience of description, some nouns or terms related to the embodiments of the present invention are explained as follows: DPF: Diesel Particulate Filter, which is used to trap particulate matter in the exhaust gas. When the mass of the trapped particulate matter reaches a certain level, passive regeneration or active regeneration is required to restore the particulate matter trapping ability of the DPF.

[0028] DOC: Diesel Oxide Catalyst, which is installed in front of the DPF and is used to convert NO in the exhaust gas into NO2, and at the same time increase the exhaust gas temperature to assist the normal operation of the DPF and SCR.

[0029] SCR: Selectively Catalytic Reduction, where urea is injected in front of the SCR to reduce nitrogen oxides in the exhaust gas, and the SCR is located far from the turbine.

[0030] ccSCR: Close-coupled SCR.

[0031] ASC: Ammonia Slip Catalyst, used for oxidizing excess ammonia.

[0032] It should be noted that the post-treatment system in the prior art does not consider the side reaction of generating N2O in SCR, and does not consider the occurrence of the N2O side reaction in SCR when controlling the urea injection amount, and the generated N2O has an impact on the environment. In order to reduce the generation amount of N2O in SCR, the present invention provides a method, device and electronic equipment for controlling the urea injection amount.

[0033] The method for controlling the urea injection amount provided by the present invention is applied to the diesel engine exhaust gas post-treatment system, and the applicable diesel engine exhaust gas post-treatment system can be a two-stage SCR post-treatment system. Figure 1 It is a schematic structural diagram of the two-stage SCR post-treatment system in the embodiment of the present invention. As Figure 1 shown, the two-stage SCR post-treatment system can include ccSCR&ASC, DOC, DPF and SCR&ASC. The system is equipped with NOx sensors NOx1, NOx2 and NOx3, and temperature sensors T4, T5, T6, T7 and T8. In the two-stage SCR post-treatment system designed by the present invention, an iron-based catalyst is used at the front end of the post-stage SCR, and a copper-based catalyst is used at the back end. The front-stage SCR can be ccSCR, that is, Figure 1 the ccSCR in Figure 1 and the post-stage SCR is the SCR in Figure 1 SCR&ASC. The iron-based catalyst is Figure 1 CAT1 in

[0034] In order to ensure sufficient conversion efficiency at low temperatures and reduce the generation of N2O on ASC, Figure 1 the ccSCR (front-stage SCR) catalyst in ccSCR&ASC can be a copper-based catalyst, and the ASC catalyst can be a copper-based catalyst + noble metal. The volume ratio of ccSCR to ASC is between 3 and 4.5. In order to reduce the generation amount of NO2 in DOC and prevent the SCR catalyst from reacting to generate N2O, the DOC catalyst can adopt a low concentration of noble metal, such as 10 g / cft of pure Pt. The SCR (post-stage SCR) catalyst in SCR&ASC adopts an iron-based catalyst + copper-based catalyst scheme. An iron-based catalyst is used at the front end of the post-stage SCR, and a copper-based catalyst is used at the immediately adjacent back end. The volume ratio of the iron-based catalyst to the copper-based catalyst can be between 0.25 and 0.4. The use of the iron-based catalyst can reduce the generation of N2O to a certain extent. Specifically, the iron-based catalyst can reduce the N2O generated at the front end of the post-stage SCR and react with NO2 at the same time, further reducing the N2O generation amount of the copper-based catalyst.

[0035] Based on the kinetic models of the iron-based catalyst and the copper-based catalyst for the post-stage SCR, the present invention determines the predicted value of the first internal ammonia storage in the post-stage SCR; based on the predicted value of the first internal ammonia storage and the set value of the internal ammonia storage in the post-stage SCR, the present invention determines the first ammonia storage corrected urea injection amount for the post-stage SCR; and based on the feedforward urea injection amount and the first ammonia storage corrected urea injection amount for the post-stage SCR, the present invention determines the total urea injection amount for the post-stage SCR. The present invention adopts a combination of an iron-based catalyst and a copper-based catalyst in the post-stage SCR, and determines the ammonia storage corrected urea injection amount based on the predicted value of the internal ammonia storage determined by the kinetic models of the iron-based catalyst and the copper-based catalyst, so as to determine the total urea injection amount for the post-stage SCR, thereby accurately controlling the urea injection amount and reducing the N2O emissions of the after-treatment system.

[0036] The following will introduce in detail the urea injection amount control method, device, and electronic device provided by the present invention with reference to the accompanying drawings.

[0037] Figure 2 It is a schematic flowchart of a urea injection control method provided by an embodiment of the present invention. As Figure 2 shown, the method may include the following steps: Step 201: Based on the kinetic models of the iron-based catalyst and the copper-based catalyst for the post-stage SCR, determine the predicted value of the first internal ammonia storage in the post-stage SCR.

[0038] Among them, both the kinetic model of the iron-based catalyst and the kinetic model of the copper-based catalyst include ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction. In some embodiments, since the chemical reaction rates of the iron-based catalyst and the copper-based catalyst are different, the kinetic models of the iron-based catalyst and the copper-based catalyst are respectively constructed to predict the internal ammonia storage in the post-stage SCR through the constructed kinetic models. As an example, the kinetic models of the iron-based catalyst and the copper-based catalyst may be constructed based on the rate equations of the above SCR chemical reactions, ammonia storage mass conservation, and the forward Euler method.

[0039] In some embodiments, the inputs of the kinetic model of the iron-based catalyst may include the exhaust gas flow rate, the inlet temperature of the post-stage SCR (such as Figure 1 the temperature of T7), and the NOx sensor upstream of the post-stage SCR (such as Figure 1The actual NOx concentration obtained by the NOx sensor, and the urea injection amount at the previous moment before the post-stage SCR. The output of the iron-based catalyst kinetic model can include the predicted value of ammonia storage inside the iron-based catalyst, and can also include the predicted value of the temperature and the predicted value of the NOx concentration downstream of the iron-based catalyst. The input of the copper-based catalyst kinetic model can include the predicted value of the temperature, the predicted value of the NOx concentration output by the iron-based catalyst kinetic model, and the exhaust gas flow rate, and the output is the predicted value of ammonia storage inside the copper-based catalyst. The sum of the predicted value of ammonia storage inside the iron-based catalyst and the predicted value of ammonia storage inside the copper-based catalyst is used as the predicted value of ammonia storage inside the post-stage SCR.

[0040] Step 202: Based on the first predicted value of ammonia storage and the set value of ammonia storage inside the post-stage SCR, determine the first ammonia storage corrected urea injection amount for the post-stage SCR.

[0041] Among them, the set value of ammonia storage inside the post-stage SCR can be determined by looking up a table. For example, the set value of ammonia storage inside the post-stage SCR can be obtained by looking up a table based on the exhaust gas flow rate of the after-treatment system and the temperature of the post-stage SCR. The temperature of the post-stage SCR used when looking up the table can be the average temperature of the post-stage SCR, and the average temperature of the post-stage SCR can be calculated by weighted average based on the upstream temperature and the downstream temperature of the post-stage SCR.

[0042] As a possible implementation, the process of determining the first ammonia storage corrected urea injection amount for the post-stage SCR based on the first predicted value of ammonia storage and the set value of ammonia storage inside the post-stage SCR may include: determining the difference between the first predicted value of ammonia storage and the set value of ammonia storage inside the post-stage, and dividing the difference by the calibration time to obtain the first ammonia storage corrected urea injection amount.

[0043] As another possible implementation, the process of determining the first ammonia storage corrected urea injection amount for the post-stage SCR based on the first predicted value of ammonia storage and the set value of ammonia storage inside the post-stage SCR may include: determining the difference between the first predicted value of ammonia storage and the set value of ammonia storage inside the post-stage, and calculating based on the difference through a PI controller to obtain the first ammonia storage corrected urea injection amount.

[0044] Step 203: Based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage corrected urea injection amount, determine the total urea injection amount of the post-stage SCR.

[0045] Among them, the feedforward urea injection amount of the post-stage SCR can be determined based on the set ammonia-nitrogen ratio of the post-stage SCR and the actual value of the NOx concentration upstream of the post-stage SCR. The actual value of the NOx concentration upstream of the post-stage SCR can be Figure 1Measured by the NOx2 sensor in []. The set ammonia-nitrogen ratio of the post-stage SCR can be obtained by looking up a table based on the temperature and exhaust gas flow rate of the post-stage SCR, and the set ammonia-nitrogen ratio is obtained. The product of the set ammonia-nitrogen ratio and the actual value of the NOx concentration upstream of the post-stage SCR gives the feedforward urea injection amount of the post-stage SCR.

[0046] In some embodiments, the sum result of the feedforward urea injection amount of the post-stage SCR and the first ammonia storage correction urea injection amount can be determined as the total urea injection amount of the post-stage SCR.

[0047] According to the urea injection amount control method of the embodiment of the present invention, an iron-based catalyst is used at the front end of the post-stage SCR in the dual-stage SCR post-treatment system, and a copper-based catalyst is used at the rear end. Based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the post-stage SCR, the first internal ammonia storage prediction value of the post-stage SCR is determined; based on the first internal ammonia storage prediction value and the internal ammonia storage set value of the post-stage SCR, the first ammonia storage correction urea injection amount of the post-stage SCR is determined; based on the feedforward urea injection amount and the first ammonia storage correction urea injection amount of the post-stage SCR, the total urea injection amount of the post-stage SCR is determined. The present invention adopts a combination of an iron-based catalyst and a copper-based catalyst in the post-stage SCR, and based on the internal ammonia storage prediction value determined by the kinetic models of the iron-based catalyst and the copper-based catalyst, the ammonia storage correction urea injection amount is determined to determine the total urea injection amount of the post-stage SCR, so that the urea injection amount can be accurately controlled and the N2O emission of the post-treatment system can be reduced.

[0048] In order to improve the accuracy of urea injection amount control, the present invention provides another embodiment.

[0049] Figure 3 It is a schematic flow chart of another urea injection amount control method provided by the embodiment of the present invention. As Figure 3 shown, the method may include the following steps: Step 301, based on the kinetic models of the iron-based catalyst and the copper-based catalyst, determine the first internal ammonia storage prediction value and the first NOx concentration prediction value downstream of the post-stage SCR.

[0050] In some embodiments, based on the kinetic models of the iron-based catalyst and the copper-based catalyst, not only the first internal ammonia storage prediction value can be obtained, but also the first NOx concentration prediction value downstream of the post-stage SCR can be obtained. For example, the kinetic model of the iron-based catalyst outputs the NOx concentration prediction value downstream of the iron-based catalyst, and the kinetic model of the copper-based catalyst outputs the first NOx concentration prediction value downstream of the post-stage SCR based on the NOx concentration prediction value downstream of the iron-based catalyst.

[0051] Step 302: Determine the first ammonia storage corrected urea injection amount for the post-stage SCR based on the first internal ammonia storage prediction value and the internal ammonia storage set value of the post-stage SCR.

[0052] Step 303: Determine the model conversion efficiency of the post-stage SCR based on the first NOx concentration prediction value and the actual first NOx concentration value upstream of the post-stage SCR.

[0053] The model conversion efficiency refers to the conversion efficiency of NOx calculated based on the NOx concentration prediction value output by the model.

[0054] As an example, the difference between the actual first NOx concentration value and the first NOx concentration prediction value, divided by the actual first NOx concentration value, can be determined as the model conversion efficiency of the post-stage SCR.

[0055] Step 304: Determine the model feedforward urea injection amount for the post-stage SCR according to the set conversion efficiency and the model conversion efficiency of the post-stage SCR.

[0056] To compensate for the deviation between the model prediction and the set value, the model feedforward urea injection amount can be introduced to make the finally obtained total urea injection amount more accurate.

[0057] In some embodiments, the ratio between the set conversion efficiency and the model conversion efficiency can be determined first, and then proportional calculation can be performed based on this ratio to obtain the model feedforward urea injection amount for the post-stage SCR.

[0058] In some other embodiments, the first difference between the set conversion efficiency and the model conversion efficiency can be determined first, and based on this first difference, the model feedforward urea injection amount can be determined. The process of determining the model feedforward urea injection amount based on the first difference can be multiplying the first difference by a preset coefficient to obtain the model feedforward urea injection amount, or calculating the model feedforward urea injection amount through a P controller based on the first difference.

[0059] Step 305: Determine the sum of the feedforward urea injection amount, the first ammonia storage corrected urea injection amount, and the model feedforward urea injection amount for the post-stage SCR, and based on the sum result, determine the total urea injection amount for the post-stage SCR.

[0060] In some embodiments, the calculated sum result can be directly determined as the total urea injection amount for the post-stage SCR, or the calculated sum result can be multiplied by a preset coefficient to obtain the total urea injection amount for the post-stage SCR.

[0061] The urea injection amount control method according to an embodiment of the present invention obtains a predicted value of the first NOx concentration downstream of the post-stage SCR based on an iron-based catalyst kinetic model and a copper-based catalyst kinetic model, introduces a model feedforward urea injection amount based on the model conversion efficiency and the set conversion efficiency, and determines the total urea injection amount of the post-stage SCR based on the sum of the feedforward urea injection amount of the post-stage SCR, the first ammonia storage correction urea injection amount, and the model feedforward urea injection amount. By introducing the model feedforward urea injection amount, the present invention can compensate for the deviation between the model prediction and the set conversion efficiency, improve the accuracy of urea injection amount control, and reduce the generation amount of N2O.

[0062] Figure 4 FIG. is a schematic flow chart of another urea injection amount control method provided by an embodiment of the present invention. As Figure 4 shown, based on the above embodiment, Figure 3 in step 305 of, the implementation process of determining the total urea injection amount of the post-stage SCR based on the sum result may include the following steps: Step 401, determine a closed-loop correction factor based on the model conversion efficiency and the actual conversion efficiency of the post-stage SCR.

[0063] Among them, the closed-loop correction factor is used to correct the deviation between the predicted NOx concentration downstream of the post-stage SCR by the model and the actual NOx concentration, so that the model prediction is closer to the actual situation. The actual conversion efficiency of the post-stage SCR can be calculated based on the actual value of the NOx concentration downstream of the post-stage SCR and the actual value of the NOx concentration upstream of the post-stage SCR. The actual value of the NOx concentration downstream of the post-stage SCR can be measured by the NOx3 sensor in the post-treatment system as Figure 1 shown.

[0064] In some embodiments, the difference between the actual conversion efficiency and the model conversion efficiency of the post-stage SCR can be calculated first, and the difference is calculated by a PI controller to obtain a closed-loop correction factor.

[0065] Step 402, determine the product of the sum result and the closed-loop correction factor as the total urea injection amount of the post-stage SCR.

[0066] According to the urea injection amount control method of an embodiment of the present invention, a closed-loop correction factor is determined by combining the model conversion efficiency and the actual conversion efficiency, and the product of the sum result and the closed-loop correction factor is determined as the total urea injection amount of the post-stage SCR to correct the deviation between the predicted NOx concentration by the model and the actual NOx concentration, realize the closed-loop control of NOx, improve the accuracy of urea injection amount control, ensure the conversion efficiency of NOx, and reduce the generation of N2O.

[0067] For Figure 2The implementation process of step 201 in [the above context] may include: inputting the inlet temperature of the post-stage SCR, the urea injection amount at the previous moment, the actual value of the first NOx concentration upstream of the post-stage SCR, and the exhaust gas flow rate into the iron-based catalyst kinetic model to obtain the predicted values of the second NOx concentration, NH3 concentration, temperature, and the predicted value of the ammonia storage inside the iron-based catalyst downstream output by the iron-based catalyst kinetic model; inputting the predicted values of the second NOx concentration, NH3 concentration, and temperature, and the exhaust gas flow rate into the copper-based catalyst kinetic model to obtain the predicted value of the ammonia storage inside the copper-based catalyst output by the copper-based catalyst kinetic model; determining the sum of the predicted value of the ammonia storage inside the iron-based catalyst and the predicted value of the ammonia storage inside the copper-based catalyst as the first predicted value of the internal ammonia storage. Among them, the copper-based catalyst kinetic model may also output the predicted value of the first NOx concentration downstream of the post-stage SCR.

[0068] Figure 5 This is an example diagram of the urea injection amount control logic for the post-stage SCR in the embodiments of the present invention, which can be combined with Figure 5 to understand the urea injection amount control method of the above embodiments.

[0069] Since the pre-stage SCR is also included in the dual-stage SCR aftertreatment system, the urea injection control method of the embodiments of the present invention may further include the control of the urea injection amount of the pre-stage SCR. Please refer to the following embodiments.

[0070] Figure 6 This is a schematic flowchart of another urea injection amount control method provided by the embodiments of the present invention. As Figure 6 shown, based on the above embodiments, this method may further include the following steps: Step 601, based on the kinetic model of the pre-stage SCR in the dual-stage SCR aftertreatment system, determine the second predicted value of the internal ammonia storage of the pre-stage SCR.

[0071] Among them, the kinetic model of the pre-stage SCR includes ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction. As an example, the kinetic model of the pre-stage SCR may be constructed based on the rate equations of the above SCR chemical reactions, the mass conservation of ammonia storage, and the forward Euler method.

[0072] In some embodiments, the inputs of the kinetic model of the pre-stage SCR may include the exhaust gas flow rate, the inlet temperature of the pre-stage SCR (such as Figure 1 the temperature at T4 in [the above context]), and based on the NOx sensor upstream of the pre-stage SCR (such as Figure 1The actual NOx concentration obtained by the NOx1 sensor in [ ], as well as the urea injection amount at the previous moment of the pre-stage SCR, the output of the kinetic model of the pre-stage SCR may include a predicted value of the second internal ammonia storage, and may also include a predicted value of the NOx concentration downstream of the pre-stage SCR, and a predicted value of the NH3 concentration downstream of the pre-stage SCR.

[0073] Step 602, based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage SCR, determine the second ammonia storage corrected urea injection amount of the pre-stage SCR.

[0074] Among them, the set value of the internal ammonia storage of the pre-stage SCR can be determined by looking up a table. For example, the set value of the internal ammonia storage of the pre-stage SCR can be obtained by looking up a table based on the exhaust gas flow rate of the aftertreatment system and the inlet temperature of the pre-stage SCR.

[0075] As a possible implementation, the process of determining the second ammonia storage corrected urea injection amount based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage SCR may include: determining the difference between the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage, and dividing the difference by the calibration time to obtain the second ammonia storage corrected urea injection amount.

[0076] As another possible implementation, the process of determining the second ammonia storage corrected urea injection amount based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage SCR may include: determining the difference between the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage SCR, and calculating based on the difference through a PI controller to obtain the second ammonia storage corrected urea injection amount.

[0077] Step 603, based on the feedforward urea injection amount of the pre-stage SCR and the second ammonia storage corrected urea injection amount, determine the total urea injection amount of the pre-stage SCR.

[0078] Among them, the feedforward urea injection amount of the pre-stage SCR can be determined based on the set ammonia-nitrogen ratio of the pre-stage SCR and the actual value of the NOx concentration upstream of the pre-stage SCR. The actual value of the NOx concentration upstream of the pre-stage SCR can be measured by Figure 1 the NOx1 sensor in [ ]. The set ammonia-nitrogen ratio of the pre-stage SCR can be obtained by looking up a table. By looking up a table based on the inlet temperature and exhaust gas flow rate of the pre-stage SCR, the set ammonia-nitrogen ratio is obtained. The product of the set ammonia-nitrogen ratio and the actual value of the NOx concentration upstream of the pre-stage SCR gives the feedforward urea injection amount of the pre-stage SCR.

[0079] In some embodiments, the sum of the feedforward urea injection amount of the pre-stage SCR and the second ammonia storage corrected urea injection amount can be determined as the total urea injection amount of the pre-stage SCR.

[0080] The urea injection amount control method according to an embodiment of the present invention determines a predicted value of the second internal ammonia storage of the pre-stage SCR based on the kinetic model of the pre-stage SCR, determines the second ammonia storage corrected urea injection amount based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage, and determines the total urea injection amount of the pre-stage SCR based on the feedforward urea injection amount and the second ammonia storage corrected urea injection amount of the pre-stage SCR. By introducing the control of the SCR, the present invention can more accurately control the urea injection amount, ensure the conversion efficiency of NOx, and reduce the generation of N2O.

[0081] In order to further improve the accuracy of urea injection amount control, the present invention also provides the following embodiments.

[0082] Figure 7 It is a schematic flow chart of another urea injection amount control method provided by an embodiment of the present invention. As Figure 7 shown, based on the above embodiment, the urea injection amount control process for the pre-stage SCR may include the following steps: Step 701, based on the kinetic model of the pre-stage SCR, determine the predicted value of the second internal ammonia storage and the predicted value of the third NOx concentration downstream of the pre-stage SCR.

[0083] Step 702, based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage SCR, determine the second ammonia storage corrected urea injection amount of the pre-stage SCR.

[0084] Step 703, based on the actual value of the first NOx concentration upstream of the post-stage SCR and the predicted value of the third NOx concentration, determine the closed-loop corrected urea injection amount of the pre-stage SCR.

[0085] Among them, the closed-loop corrected urea injection amount of the pre-stage SCR is used to correct the deviation between the NOx concentration predicted by the model and the actual NOx concentration.

[0086] In some embodiments, the difference between the actual value of the first NOx concentration and the predicted value of the third NOx concentration may be determined first, and the closed-loop corrected urea injection amount may be calculated based on this difference through a P controller.

[0087] Step 704, sum the feedforward urea injection amount, the second ammonia storage corrected urea injection amount, and the closed-loop corrected urea injection amount of the pre-stage SCR, and determine it as the total urea injection amount of the pre-stage SCR.

[0088] The urea injection amount control method according to an embodiment of the present invention determines the closed-loop corrected urea injection amount based on the predicted value and the actual value of the NOx concentration, and then determines the total urea injection amount of the front-stage SCR by adding the feedforward urea injection amount of the front-stage SCR, the second ammonia storage corrected urea injection amount, and the closed-loop corrected urea injection amount. Through closed-loop control, the accuracy of urea injection amount control can be improved, the conversion efficiency of NOx can be ensured, and the generation of N2O can be reduced.

[0089] In some embodiments, in order to prevent NH3 leakage from the front-stage SCR from entering the DOC to generate N2O, before the urea injection amount control process of the front-stage SCR in the above embodiment, an NH3 leakage judgment logic can be added to prevent the cross-sensitivity of NOx to NH3 from affecting the closed-loop control and continuously increasing the urea injection amount. As an example, the leakage judgment method may include: monitoring the actual conversion efficiency of the front-stage SCR; if the actual conversion efficiency is less than a preset threshold, increasing the ammonia-nitrogen ratio at a preset rate, that is, by increasing the feedforward urea injection amount of the front-stage SCR and increasing the total urea injection amount of the front-stage SCR; when the ammonia-nitrogen ratio increases and the actual conversion efficiency decreases, it is determined that NH3 leakage occurs, and then the ammonia-nitrogen ratio is decreased at a preset rate, that is, the total urea injection amount of the front-stage SCR is decreased, until the actual conversion efficiency is greater than or equal to the threshold, and then the urea injection amount control process for the front-stage SCR in the above embodiment is executed.

[0090] Figure 8 This is an example diagram of the urea injection amount control logic for a front-stage SCR in an embodiment of the present invention, which can be combined with Figure 8 to understand the urea injection amount control method of the above embodiment.

[0091] To implement the above embodiment, the present invention also provides a urea injection amount control device.

[0092] Figure 9 This is a structural schematic diagram of a urea injection amount control device provided by an embodiment of the present invention. The device is applied to a two-stage SCR after-treatment system. The front end of the rear-stage SCR in the two-stage SCR after-treatment system uses an iron-based catalyst, and the rear end uses a copper-based catalyst. As Figure 9 shown, the device may include: a first determination module 901, a second determination module 902, and a third determination module 903.

[0093] The first determination module 901 is configured to determine a first internal ammonia storage predicted value of the rear-stage SCR based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the rear-stage SCR; both the kinetic model of the iron-based catalyst and the kinetic model of the copper-based catalyst include ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; The second determination module 902 is configured to determine the first ammonia storage corrected urea injection amount of the post-stage SCR based on the first internal ammonia storage prediction value and the internal ammonia storage set value of the post-stage SCR; The third determination module 903 is configured to determine the total urea injection amount of the post-stage SCR based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage corrected urea injection amount.

[0094] In some embodiments, the first determination module 901 is specifically configured to: Based on the iron-based catalyst kinetic model and the copper-based catalyst kinetic model, determine the first internal ammonia storage prediction value and the first NOx concentration prediction value downstream of the post-stage SCR; The third determination module is specifically configured to: Based on the first NOx concentration prediction value and the actual value of the first NOx concentration upstream of the post-stage SCR, determine the model conversion efficiency of the post-stage SCR; According to the set conversion efficiency and the model conversion efficiency of the post-stage SCR, determine the model feedforward urea injection amount of the post-stage SCR; Determine the sum result of the feedforward urea injection amount, the first ammonia storage corrected urea injection amount, and the model feedforward urea injection amount of the post-stage SCR, and based on the sum result, determine the total urea injection amount of the post-stage SCR.

[0095] As a possible implementation, the third determination module 903 is further configured to: Determine the first difference between the set conversion efficiency and the model conversion efficiency; Based on the first difference, determine the model feedforward urea injection amount.

[0096] In some embodiments, the third determination module 903 is further configured to: Based on the model conversion efficiency and the actual conversion efficiency of the post-stage SCR, determine the closed-loop correction factor; Determine the product of the sum result and the closed-loop correction factor as the total urea injection amount of the post-stage SCR.

[0097] As a possible implementation, the first determination module 901 is specifically configured to: Input the inlet temperature of the post-stage SCR, the urea injection amount at the previous moment, the actual value of the first NOx concentration upstream of the post-stage SCR, and the exhaust gas flow rate into the iron-based catalyst kinetic model to obtain the second NOx concentration prediction value, NH3 concentration prediction value, temperature prediction value, and iron-based internal ammonia storage prediction value output by the iron-based catalyst kinetic model; Input the second NOx concentration prediction value, the NH3 concentration prediction value, the temperature prediction value, and the exhaust gas flow rate into the copper-based catalyst kinetic model to obtain the copper-based internal ammonia storage prediction value output by the copper-based catalyst kinetic model; Determine the sum of the iron-based internal ammonia storage prediction value and the copper-based internal ammonia storage prediction value as the first internal ammonia storage prediction value.

[0098] In some embodiments, the device further includes: A fourth determination module 904, configured to determine a second internal ammonia storage prediction value of the pre-stage SCR based on the kinetic model of the pre-stage SCR in the two-stage SCR aftertreatment system; wherein, the kinetic model of the pre-stage SCR includes ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; A fifth determination module 905, configured to determine a second ammonia storage correction urea injection amount of the pre-stage SCR based on the second internal ammonia storage prediction value and the internal ammonia storage set value of the pre-stage SCR; A sixth determination module 906, configured to determine the total urea injection amount of the pre-stage SCR based on the feedforward urea injection amount and the second ammonia storage correction urea injection amount of the pre-stage SCR.

[0099] In some embodiments, the fourth determination module 904 is further configured to: Based on the kinetic model of the pre-stage SCR, determine the second internal ammonia storage prediction value and the third NOx concentration prediction value downstream of the pre-stage SCR; In some embodiments, the sixth determination module 906 is further configured to: Based on the actual value of the first NOx concentration upstream of the post-stage SCR and the third NOx concentration prediction value, determine the closed-loop correction urea injection amount of the pre-stage SCR; Determine the sum of the feedforward urea injection amount, the second ammonia storage correction urea injection amount, and the closed-loop correction urea injection amount of the pre-stage SCR as the total urea injection amount of the pre-stage SCR.

[0100] For the urea injection amount control device according to the present invention, an iron-based catalyst is used at the front end of the post-stage SCR in the dual-stage SCR aftertreatment system, and a copper-based catalyst is used at the rear end. Based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the post-stage SCR, a first internal ammonia storage prediction value of the post-stage SCR is determined; based on the first internal ammonia storage prediction value and the internal ammonia storage set value of the post-stage SCR, a first ammonia storage corrected urea injection amount of the post-stage SCR is determined; based on the feed-forward urea injection amount and the first ammonia storage corrected urea injection amount of the post-stage SCR, the total urea injection amount of the post-stage SCR is determined. In the present invention, a combination of an iron-based catalyst and a copper-based catalyst is used in the post-stage SCR, and based on the internal ammonia storage prediction value determined by the kinetic models of the iron-based catalyst and the copper-based catalyst, the ammonia storage corrected urea injection amount is determined to determine the total urea injection amount of the post-stage SCR, so that the urea injection amount can be accurately controlled and the N2O emission of the aftertreatment system can be reduced.

[0101] It should be noted that the explanations in the above embodiments of the urea injection amount control method are equally applicable to the urea injection amount control device in the embodiments of the present invention, and will not be elaborated here.

[0102] Figure 10 An entity structure diagram of an electronic device is exemplified, as Figure 10 shown, the electronic device may include: a processor 1010, a communication interface 1020, a memory 1030, and a communication bus 1040. Among them, the processor 1010, the communication interface 1020, and the memory 1030 complete mutual communication through the communication bus 1040. The processor 1010 can call the computer program in the memory 1030 to execute the steps of the urea injection amount control method provided in the above embodiments.

[0103] For example, the method includes: based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the post-stage SCR, determining a first internal ammonia storage prediction value of the post-stage SCR; both the iron-based catalyst kinetic model and the copper-based catalyst kinetic model include ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; based on the first internal ammonia storage prediction value and the internal ammonia storage set value of the post-stage SCR, determining a first ammonia storage corrected urea injection amount of the post-stage SCR; based on the feed-forward urea injection amount and the first ammonia storage corrected urea injection amount of the post-stage SCR, determining the total urea injection amount of the post-stage SCR.

[0104] In addition, when the logical instructions in the above-mentioned memory 1030 are implemented in the form of software functional units and sold or used as independent products, they can be stored in a computer-readable storage medium. Based on such an understanding, the technical solution of the present invention, in essence, or the part that contributes to the prior art, or a part of the technical solution, can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computer device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the steps of the methods described in various embodiments of the present invention. The foregoing storage medium includes: various media that can store program codes, such as USB flash drives, mobile hard disks, read-only memories (ROM, Read-Only Memory), random access memories (RAM, Random Access Memory), magnetic disks, or optical discs.

[0105] On the other hand, an embodiment of the present invention further provides a computer program product. The computer program product includes a computer program that can be stored on a computer-readable storage medium. When the computer program is executed by a processor, the computer can execute the steps of the urea injection amount control method provided in the above-mentioned embodiment.

[0106] On the other hand, an embodiment of the present invention further provides a computer-readable storage medium. The computer-readable storage medium stores a computer program, and the computer program is used to cause a processor to execute the urea injection amount control methods provided in the above-mentioned embodiments.

[0107] The computer-readable storage medium may be any available medium or data storage device accessible by the processor, including but not limited to magnetic memories (such as floppy disks, hard disks, magnetic tapes, magneto-optical discs (MO), etc.), optical memories (such as CDs, DVDs, BDs, HVDs, etc.), and semiconductor memories (such as ROM, EPROM, EEPROM, non-volatile memories (NANDFLASH), solid-state drives (SSD)).

[0108] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separated, and the components shown as units may or may not be physical units, that is, they may be located in one place or distributed to multiple network units. Some or all of the modules can be selected according to actual needs to achieve the purpose of the solution of this embodiment. A person of ordinary skill in the art can understand and implement it without creative labor.

[0109] Through the description of the above embodiments, those skilled in the art can clearly understand that each embodiment can be implemented by means of software plus a necessary general hardware platform, and of course, it can also be implemented by hardware. Based on such an understanding, the essence of the above technical solution, or the part that contributes to the prior art, can be embodied in the form of a software product. The computer software product can be stored in a computer-readable storage medium, such as ROM / RAM, magnetic disk, optical disk, etc., and includes several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute the methods described in each embodiment or some parts of the embodiments.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for controlling the urea injection amount, characterized in that, The method is applied to a two-stage SCR aftertreatment system; a front end of a post-stage SCR in the two-stage SCR aftertreatment system uses an iron-based catalyst, and a rear end uses a copper-based catalyst; the method includes: Based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the post-stage SCR, determining a first predicted value of the internal ammonia storage of the post-stage SCR; both the kinetic model of the iron-based catalyst and the kinetic model of the copper-based catalyst include ammonia adsorption-desorption reactions, standard reactions, fast reactions, slow reactions, ammonia oxidation reactions, and N2O generation reactions; Based on the first predicted value of the internal ammonia storage and the set value of the internal ammonia storage of the post-stage SCR, determining a first ammonia storage corrected urea injection amount of the post-stage SCR; Based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage corrected urea injection amount, determining the total urea injection amount of the post-stage SCR.

2. The method according to claim 1, wherein The determining the first predicted value of the internal ammonia storage of the post-stage SCR based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the post-stage SCR includes: Based on the kinetic models of the iron-based catalyst and the copper-based catalyst, determining the first predicted value of the internal ammonia storage and a first predicted value of the NOx concentration downstream of the post-stage SCR; The determining the total urea injection amount of the post-stage SCR based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage corrected urea injection amount includes: Based on the first predicted value of the NOx concentration and the actual value of the first NOx concentration upstream of the post-stage SCR, determining the model conversion efficiency of the post-stage SCR; According to the set conversion efficiency and the model conversion efficiency of the post-stage SCR, determining the model feedforward urea injection amount of the post-stage SCR; Determining the sum result of the feedforward urea injection amount, the first ammonia storage corrected urea injection amount, and the model feedforward urea injection amount of the post-stage SCR, and based on the sum result, determining the total urea injection amount of the post-stage SCR.

3. The method according to claim 2, wherein The determining the model feedforward urea injection amount of the post-stage SCR according to the set conversion efficiency and the model conversion efficiency of the post-stage SCR includes: Determining a first difference between the set conversion efficiency and the model conversion efficiency; Based on the first difference, determining the model feedforward urea injection amount.

4. The method according to claim 2, wherein The determining the total urea injection amount of the post-stage SCR based on the sum result includes: Based on the model conversion efficiency and the actual conversion efficiency of the post-stage SCR, determining a closed-loop correction factor; Taking the product of the sum result and the closed-loop correction factor as the total urea injection amount of the post-stage SCR.

5. The method according to claim 1, characterized in that The determining the first predicted value of the internal ammonia storage of the post-stage SCR based on the kinetic models of the iron-based catalyst and the copper-based catalyst of the post-stage SCR includes: Input the inlet temperature of the post-stage SCR, the urea injection amount at the previous moment, the actual value of the first NOx concentration upstream of the post-stage SCR, and the exhaust gas flow rate into the iron-based catalyst kinetic model to obtain the predicted value of the second NOx concentration downstream of the iron-based catalyst, the predicted value of the NH3 concentration, the predicted value of the temperature, and the predicted value of the ammonia storage inside the iron-based catalyst output by the iron-based catalyst kinetic model; Input the predicted value of the second NOx concentration, the predicted value of the NH3 concentration, the predicted value of the temperature, and the exhaust gas flow rate into the copper-based catalyst kinetic model to obtain the predicted value of the ammonia storage inside the copper-based catalyst output by the copper-based catalyst kinetic model; Determine the sum of the predicted value of the ammonia storage inside the iron-based catalyst and the predicted value of the ammonia storage inside the copper-based catalyst as the predicted value of the first internal ammonia storage.

6. The method according to any one of claims 1 to 5, characterized in that, The method further includes: Determine the predicted value of the second internal ammonia storage of the pre-stage SCR based on the kinetic model of the pre-stage SCR in the dual-stage SCR aftertreatment system; wherein, the kinetic model of the pre-stage SCR includes ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; Determine the second ammonia storage correction urea injection amount of the pre-stage SCR based on the predicted value of the second internal ammonia storage and the set value of the internal ammonia storage of the pre-stage SCR; Determine the total urea injection amount of the pre-stage SCR based on the feedforward urea injection amount of the pre-stage SCR and the second ammonia storage correction urea injection amount.

7. The method according to claim 6, wherein The determining the predicted value of the second internal ammonia storage of the pre-stage SCR based on the kinetic model of the pre-stage SCR in the dual-stage SCR aftertreatment system includes: Determine the predicted value of the second internal ammonia storage and the predicted value of the third NOx concentration downstream of the pre-stage SCR based on the kinetic model of the pre-stage SCR; The determining the total urea injection amount of the pre-stage SCR based on the feedforward urea injection amount of the pre-stage SCR and the second ammonia storage correction urea injection amount includes: Determine the closed-loop correction urea injection amount of the pre-stage SCR based on the actual value of the first NOx concentration upstream of the post-stage SCR and the predicted value of the third NOx concentration; Determine the sum of the feedforward urea injection amount of the pre-stage SCR, the second ammonia storage correction urea injection amount, and the closed-loop correction urea injection amount as the total urea injection amount of the pre-stage SCR.

8. An urea injection amount control device, characterized in that, The device is applied to a dual-stage SCR aftertreatment system; the front end of the post-stage SCR in the dual-stage SCR aftertreatment system uses an iron-based catalyst, and the rear end uses a copper-based catalyst; the device includes: A first determination module for determining the predicted value of the first internal ammonia storage of the post-stage SCR based on the iron-based catalyst kinetic model and the copper-based catalyst kinetic model of the post-stage SCR; both the iron-based catalyst kinetic model and the copper-based catalyst kinetic model include ammonia adsorption-desorption reaction, standard reaction, fast reaction, slow reaction, ammonia oxidation reaction, and N2O generation reaction; A second determination module for determining the first ammonia storage correction urea injection amount of the post-stage SCR based on the predicted value of the first internal ammonia storage and the set value of the internal ammonia storage of the post-stage SCR; A third determination module, configured to determine the total urea injection amount of the post-stage SCR based on the feedforward urea injection amount of the post-stage SCR and the first ammonia storage correction urea injection amount.

9. An electronic device, comprising a processor and a memory storing a computer program, characterized in that, When the processor executes the computer program, it implements the urea injection amount control method according to any one of claims 1 to 7.

10. A computer-readable storage medium, characterized in that, A computer program is stored thereon, and the computer program can be executed by a processor to implement the urea injection control method according to any one of claims 1 to 7.

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