Method, device, storage medium and electronic device for preventing generation of n2o

Abstract

The application provides a method, device, storage medium and electronic equipment for preventing N2O generation. The method comprises: determining whether the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold when the temperature rise rate of the front-stage SCR is greater than the temperature rise rate threshold; determining whether the temperature of the DOC is in the preset temperature range when the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold; reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the urea nozzle injection, or controlling the urea nozzle to delay injection, to prevent N2O generation due to the leakage of the front-stage SCR when the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold. Based on the double-SCR aftertreatment system, the urea injection of the front-stage SCR is logically controlled to prevent NH3 leakage of the front-stage SCR caused by the sudden increase of the engine temperature, and the problem that NH3 is oxidized into N2O in the DOC is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vehicle emission control, in particular to a method and device for preventing N2O generation, a storage medium and an electronic device. BACKGROUND

[0002] With the tightening of next-generation emission regulations, the current national VI aftertreatment technology route is difficult to meet the requirements of next-generation emission regulations, and reducing NOx emissions during engine cold start has become a key work. In addition, the emission regulations have added a limit value for the unconventional pollutant N2O.

[0003] Currently, major aftertreatment manufacturers mainly research double-SCR aftertreatment routes, and through thermal management means, the cold start of the tightly coupled SCR is quickly ignited, urea injection is performed, and the specific emission of cold start NOx is reduced, so as to meet the NOx emission limit value. Due to the complex and variable transient conditions of the engine, the double-SCR technology route is prone to NH3 leakage downstream of the front SCR, which leads to the oxidation of NH3 into N2O in the DOC. The existing solutions have no positive effect on preventing N2O generation. SUMMARY

[0004] The main purpose of the present application is to provide a method and device for preventing N2O generation, a storage medium and an electronic device, so as to at least solve the problem of N2O generation in the double-SCR aftertreatment route which cannot be solved by the existing technical solutions.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a method for preventing N2O generation is provided, which is applied to a controller of a double-SCR aftertreatment system, the double-SCR aftertreatment system further comprising a front SCR, a front ASC, a DOC, a DPF, a rear SCR and a rear ACS connected in sequence, and a urea nozzle is installed upstream of the front SCR and upstream of the rear SCR, comprising: in the case that the temperature rise rate of the front SCR is greater than a temperature rise rate threshold value, determining whether the real-time ammonia storage in the front SCR is greater than an ammonia storage threshold value; in the case that the real-time ammonia storage in the front SCR is greater than the ammonia storage threshold value, determining whether the temperature of the DOC is in a preset temperature interval; in the case that the temperature of the DOC is in the preset temperature interval and the temperature of the rear SCR is greater than a temperature threshold value, reducing the injection amount of the urea nozzle upstream of the front SCR, or stopping the urea nozzle upstream of the front SCR from injecting, or controlling the urea nozzle upstream of the front SCR to delay injection, so as to prevent N2O from being generated by oxidation through the DOC due to NH3 leakage of the front SCR.

[0006] Optionally, after reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the injection of the urea nozzle upstream of the front-stage SCR, or controlling the delayed injection of the urea nozzle upstream of the front-stage SCR, the method further comprises: obtaining the real-time ammonia storage amount inside the front-stage SCR again after a first preset time period; in the case that the obtained real-time ammonia storage amount is less than the ammonia storage threshold, controlling the injection amount of the urea nozzle of the front-stage SCR to return to the normal injection amount, and the normal injection amount is an injection amount that meets the emission requirements.

[0007] Optionally, before determining whether the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage threshold in the case that the temperature rise rate of the front-stage SCR is greater than the temperature rise rate threshold, the method further comprises: constructing an ammonia storage calculation model; determining the real-time ammonia storage amount inside the front-stage SCR using the ammonia storage calculation model; and before determining whether the temperature of the DOC is in the preset temperature range in the case that the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage threshold, the method further comprises: obtaining the current temperature of the front-stage SCR; and determining the ammonia storage threshold corresponding to the current temperature.

[0008] Optionally, determining the real-time ammonia storage amount inside the front-stage SCR using the ammonia storage calculation model comprises: obtaining the converted ammonia value upstream of the front-stage SCR, the converted ammonia value downstream of the front-stage SCR, and the converted ammonia value of the front-stage SCR converted from injected urea, respectively; performing window integration on a plurality of converted ammonia values upstream of the front-stage SCR, a plurality of converted ammonia values downstream of the front-stage SCR, and a plurality of converted ammonia values of the front-stage SCR converted from injected urea obtained within a second preset time period, respectively, to obtain a first ammonia integral value, a second ammonia integral value, and a third ammonia integral value; and determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage amount inside the front-stage SCR.

[0009] Optionally, after determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage amount inside the front-stage SCR, the method further comprises: obtaining the ammonia storage difference value between the real-time ammonia storage amount inside the front-stage SCR and the ammonia storage threshold; obtaining the maximum ammonia conversion value of the front-stage ASC at the current temperature; obtaining the ratio of the ammonia storage difference value to the maximum ammonia conversion value of the front-stage ASC; performing normalization processing on the ratio to obtain a normalization result, and using the normalization result to correct the original urea injection amount to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the injection of the urea nozzle upstream of the front-stage SCR, or control the delayed injection of the urea nozzle upstream of the front-stage SCR.

[0010] Optionally, the method further comprises: in the case that the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is less than or equal to the temperature threshold, controlling the injection amount of the urea nozzle to remain unchanged.

[0011] Optionally, the method further comprises: obtaining a corresponding relationship between the temperature of the rear-stage SCR and the conversion efficiency of the rear-stage SCR for NOx; and the method further comprises: in the case that the temperature of the rear-stage SCR is greater than the temperature threshold, determining that the conversion efficiency of the rear-stage SCR for NOx is greater than an efficiency threshold, the efficiency threshold and the temperature threshold satisfying the corresponding relationship.

[0012] According to another aspect of the present application, there is provided a device for preventing N2O generation, the device being applied to a controller of a dual-SCR aftertreatment system, the dual-SCR aftertreatment system further comprising a front-stage SCR, a front-stage ASC, a DOC, a DPF, a rear-stage SCR and a rear-stage ACS connected in sequence, and a urea nozzle being installed upstream of the front-stage SCR and upstream of the rear-stage SCR, the device comprising: a first determination unit configured to determine whether a real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold in the case that a temperature rising rate of the front-stage SCR is greater than a temperature rising rate threshold; a second determination unit configured to determine whether a temperature of the DOC is in a preset temperature range in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold; and a control unit configured to reduce an injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle upstream of the front-stage SCR from injecting, or control the urea nozzle upstream of the front-stage SCR to delay injection in the case that the temperature of the DOC is in the preset temperature range and a temperature of the rear-stage SCR is greater than a temperature threshold, so as to prevent N2O from being generated due to NH3 leakage of the front-stage SCR.

[0013] According to still another aspect of the present application, there is provided a computer readable storage medium, characterized in that the computer readable storage medium comprises a stored program, wherein the program, when executed, controls a device in which the computer readable storage medium is located to perform any of the methods for preventing N2O generation.

[0014] According to yet another aspect of the present application, there is provided an electronic device, characterized in that it comprises one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs comprise instructions for performing any of the methods for preventing N2O generation.

[0015] The technical scheme of the application is applied to determine whether the real-time ammonia storage in the front SCR is greater than the ammonia storage threshold value when the temperature rising rate of the front SCR is greater than the temperature rising rate threshold value; to determine whether the temperature of the DOC is in the preset temperature range when the real-time ammonia storage in the front SCR is greater than the ammonia storage threshold value; and to reduce the injection amount of the urea nozzle upstream of the front SCR, or to stop the urea nozzle upstream of the front SCR from injecting, or to control the urea nozzle upstream of the front SCR to delay injection, to prevent the generation of N2O due to the leakage of the front SCR, when the temperature of the DOC is in the preset temperature range and the temperature of the rear SCR is greater than the temperature threshold value. The scheme is based on a double-SCR aftertreatment system, and controls the urea injection of the front SCR through logic to prevent the leakage of NH3 in the front SCR due to the sudden increase of the engine temperature, and solves the problem of the oxidation of NH3 into N2O in the DOC. BRIEF DESCRIPTION OF DRAWINGS

[0016] The accompanying drawings, which form a part of the specification, are included to provide a further understanding of the application and are incorporated herein in conjunction with the description of the application. The drawings are as follows:

[0017] Figure 1 A hardware structure block diagram of a mobile terminal for executing a method for preventing N2O generation according to an embodiment of the application is shown;

[0018] Figure 2 A flowchart of a method for preventing N2O generation according to an embodiment of the application is shown;

[0019] Figure 3 A structure diagram of a double-SCR aftertreatment system for preventing N2O generation according to an embodiment of the application is shown;

[0020] Figure 4 A control logic diagram of a method for preventing N2O generation according to an embodiment of the application is shown;

[0021] Figure 5 A urea injection correction diagram of a front SCR of a method for preventing N2O generation according to an embodiment of the application is shown;

[0022] Figure 6 A structure block diagram of an apparatus for preventing N2O generation according to an embodiment of the application is shown.

[0023] The above drawings include the following reference signs:

[0024] 10 ccSCR; 20 ccASC; 30 DOC; 40 DPF; 50 ufSCR; 60 ufASC; 70 urea nozzle; 71 first urea nozzle; 72 second urea nozzle; 80 NOx sensor; 81 first NOx sensor; 82 second NOx sensor; 83 third NOx sensor; 90 temperature sensor; 91 first temperature sensor; 92 second temperature sensor; 93 third temperature sensor; 94 fourth temperature sensor; 95 fifth temperature sensor. DETAILED DESCRIPTION

[0025] It should be noted that the embodiments and features of the embodiments in the present application can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0026] In order for those skilled in the technical field to better understand the scheme of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor should be within the scope of protection of the present application.

[0027] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above-mentioned drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented. In addition, the terms "include" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device that includes a series of steps or units does not necessarily have to be limited to those steps or units clearly listed, but can include other steps or units that are not clearly listed or inherent to these processes, methods, products or devices.

[0028] For the convenience of description, the following describes some nouns or terms related to the embodiments of the present application:

[0029] ccSCR: close-coupled SCR, close to the outlet of the turbine.

[0030] ccASC: close-coupled ASC, arranged at the outlet position of the ccSCR, for trapping ammonia leakage.

[0031] As described in the background section, existing technical solutions cannot solve the problem of N2O generation in the dual SCR post-processing route. To address the issue of N2O generation in the dual SCR post-processing route, embodiments of this application provide a method, apparatus, storage medium, and electronic device for preventing N2O generation.

[0032] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0033] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal for a method to prevent N2O generation according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0034] The memory 104 can be used to store computer programs, such as software programs of application software and modules, such as a computer program corresponding to the method for preventing N2O generation in the embodiments of the present application. The processor 102 can execute various functional applications and data processing, i.e., implement the above method, by running the computer programs stored in the memory 104. The memory 104 can include a high-speed random access memory, and can further include a non-volatile memory, such as one or more magnetic storage devices, flash memories, or other non-volatile solid-state memories. In some examples, the memory 104 can further include memories remotely arranged with respect to the processor 102, which can be connected to the mobile terminal through a network. Examples of the above network include, but are not limited to, the Internet, an intranet, a local area network, a mobile communication network, and a combination thereof. The transmission device 106 is used to receive or send data via a network. The specific examples of the above network can include a wireless network provided by a communication provider of the mobile terminal. In one example, the transmission device 106 includes a network adapter (NIC), which can be connected to other network devices through a base station so as to communicate with the Internet. In one example, the transmission device 106 can be a radio frequency (RF) module, which is used to communicate with the Internet in a wireless manner.

[0035] In the embodiments, a method for preventing N2O generation running on a mobile terminal, a computer terminal or a similar computing device is provided. It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown.

[0036] Figure 2 is a flowchart of the method for preventing N2O generation according to the embodiments of the present application. As shown in Figure 2 , the method comprises the following steps:

[0037] In step S201, in the case that the temperature rising rate of the front-stage SCR is greater than the temperature rising rate threshold, it is determined whether the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold.

[0038] In the embodiments, the front-stage SCR is a ccSCR.

[0039] For example, the temperature of the ccSCR rises by 100°C in 5s, i.e., the temperature rising rate is 20°C / s, and if the temperature rising rate threshold is 15°C / s, the temperature rising rate of the ccSCR is greater than the temperature rising rate threshold, and it is necessary to determine the ammonia storage in the ccSCR.

[0040] Specifically, by calculating the relationship between the temperature rise rate of the ccSCR and the temperature rise rate threshold, it can be determined whether the engine temperature is suddenly increased, and the problem of NH3 leakage of the ccSCR caused by the sudden increase of the engine temperature is prevented.

[0041] Step S202, in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold, it is determined whether the temperature of the DOC is in the preset temperature range;

[0042] Wherein, the real-time ammonia storage in the ccSCR is greater than the ammonia storage threshold, which will cause the NH3 leakage in the ccSCR;

[0043] Wherein, the preset temperature range of the DOC generally includes 200℃-350℃, but is not limited to 200℃-350℃, and in the case that the temperature of the DOC is in this temperature range, the NH3 leaked from the ccSCR will be converted into N2O.

[0044] Step S203, in the case that the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold, the injection amount of the urea nozzle upstream of the front-stage SCR is reduced, or the urea nozzle upstream of the front-stage SCR is stopped from injection, or the urea nozzle upstream of the front-stage SCR is controlled to delay injection, so as to prevent the N2O generated by the oxidation of the DOC due to the NH3 leakage of the front-stage SCR.

[0045] Wherein, the rear-stage SCR is a ufSCR;

[0046] Wherein, N2O is a new unconventional pollutant added in the emission regulations;

[0047] Specifically, in the case that the temperature of the ufSCR is greater than the temperature threshold, the conversion capacity of the ufSCR reaches the peak value, and the ufSCR can play a dominant role in converting NOx, that is, even if the ccSCR is reduced or stopped from injection, all the NOx in the vehicle exhaust can be completely converted, so that the generation of N2O is prevented, and the vehicle emission can meet the national standards.

[0048] In the embodiment, in the case that the temperature rising rate of the front-stage SCR is greater than the temperature rising rate threshold, it is determined whether the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold; in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold, it is determined whether the temperature of the DOC is in the preset temperature range; in the case that the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold, the injection amount of the urea nozzle upstream of the front-stage SCR is reduced, or the urea nozzle upstream of the front-stage SCR is stopped from injecting, or the urea nozzle upstream of the front-stage SCR is controlled to delay injection, so as to prevent the generation of the DOC oxidation due to the leakage of the front-stage SCR. The scheme is based on the double-SCR aftertreatment system, and the urea injection of the front-stage SCR is controlled by logic to prevent the NH3 leakage of the front-stage SCR due to the sudden increase of the engine temperature, and the problem that NH3 is oxidized into N2O in the DOC is solved.

[0049] In the implementation process, after the injection amount of the urea nozzle upstream of the front-stage SCR is reduced, or the urea nozzle upstream of the front-stage SCR is stopped from injecting, or the urea nozzle upstream of the front-stage SCR is controlled to delay injection, the method further comprises: after a first preset time period, the real-time ammonia storage in the front-stage SCR is acquired again; in the case that the real-time ammonia storage acquired again is less than the ammonia storage threshold, the injection amount of the urea nozzle of the front-stage SCR is controlled to return to the normal injection amount, and the normal injection amount is the injection amount meeting the emission requirement.

[0050] The first preset time period can be 5 minutes, 10 minutes, 15 minutes, etc., and can be selected according to actual needs by those skilled in the art.

[0051] Specifically, after the injection amount of the urea nozzle upstream of the ccSCR is reduced, stopped or delayed, the real-time ammonia storage in the ccSCR is acquired again after a preset time period, and compared with the ammonia storage threshold at this moment. If the real-time ammonia storage is less than the ammonia storage threshold at this moment, it is considered that the ccSCR will not leak NH3, and N2O will not be generated. If the real-time ammonia storage is still greater than the ammonia storage threshold at this moment, the injection amount of the urea nozzle upstream of the ccSCR continues to be reduced, stopped or delayed until a preset time period, and the real-time ammonia storage in the ccSCR is compared with the ammonia storage threshold at this moment again.

[0052] Specifically, in the case that the temperature rise rate of the preceding SCR is greater than the temperature rise rate threshold, before determining whether the real-time ammonia storage in the preceding SCR is greater than the ammonia storage threshold, the method further comprises: constructing an ammonia storage calculation model; determining the real-time ammonia storage in the preceding SCR using the ammonia storage calculation model; and before determining whether the temperature of the DOC is in the preset temperature range in the case that the real-time ammonia storage in the preceding SCR is greater than the ammonia storage threshold, the method further comprises: obtaining the current temperature of the preceding SCR; and determining the ammonia storage threshold corresponding to the current temperature.

[0053] wherein the ammonia storage calculation model is a ccSCR reaction kinetics model;

[0054] Specifically, the ammonia storage threshold varies with temperature, so the temperature of the ccSCR needs to be obtained first, and then the ammonia storage threshold is determined according to the temperature of the ccSCR. The table pre-stores the correspondence between the temperature of the ccSCR and the ammonia storage threshold.

[0055] More specifically, determining the real-time ammonia storage in the preceding SCR using the ammonia storage calculation model comprises: obtaining the ammonia value converted upstream of the preceding SCR, the ammonia value converted downstream of the preceding SCR, and the ammonia value converted by the preceding SCR from injected urea, respectively; performing window integration on the plurality of ammonia values converted upstream of the preceding SCR, the plurality of ammonia values converted downstream of the preceding SCR, and the plurality of ammonia values converted by the preceding SCR from injected urea obtained in the second preset time period, respectively, to obtain a first ammonia integral value, a second ammonia integral value, and a third ammonia integral value; and determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage in the preceding SCR.

[0056] wherein the window integration refers to the process of accumulating and summing the data in a period of time. Under normal circumstances, window integration will sum the data in a certain time range in order to obtain the total amount or sum in that time period. The window integration time can be calibrated according to the actual situation of the test bench;

[0057] Specifically, the window integration time is adjusted and optimized according to the specific environment and conditions of the test bench. Because the test bench can simulate real road driving conditions, including different speeds, loads and environmental conditions, calibration according to the test bench results can more accurately determine the optimal window integration time to achieve the best performance and fuel economy of the engine and vehicle. Therefore, calibration according to the test bench can ensure that the engine can achieve the best performance and fuel economy in actual driving.

[0058] Further, after determining the difference between the first ammonia integral value and the ammonia integral value as the real-time ammonia storage in the front-stage SCR, the method further comprises: obtaining an ammonia storage difference between the real-time ammonia storage in the front-stage SCR and an ammonia storage threshold; obtaining a maximum ammonia conversion value of the front-stage ASC at a current temperature; obtaining a ratio of the ammonia storage difference to the maximum ammonia conversion value of the front-stage ASC; performing normalization processing on the ratio to obtain a normalized result, and correcting the original urea injection amount by using the normalized result to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle injection upstream of the front-stage SCR, or control the urea nozzle to delay injection upstream of the front-stage SCR.

[0059] wherein the front-stage ASC is a ccASC, the maximum ammonia conversion value of the ccASC is related to temperature, the temperature of the ccASC is first obtained, and then the maximum ammonia conversion value of the ccASC at the current temperature is obtained according to the temperature of the ccASC;

[0060] Specifically, the ratio of the ammonia storage difference in the ccSCR to the maximum ammonia conversion value of the ccASC is normalized, so that a parameter of 0-1 can be obtained, and the original urea injection amount is multiplied by this parameter, so that the injection amount of the urea nozzle of the ccSCR can be corrected to prevent ammonia leakage of the ccSCR.

[0061] Further, the method further comprises: in the case that the temperature of the DOC is in a preset temperature range and the temperature of the rear-stage SCR is less than or equal to a temperature threshold, controlling the injection amount of the urea nozzle to remain unchanged.

[0062] wherein the rear-stage SCR is a ufSCR;

[0063] The method determines whether the urea injection amount of the ccSCR needs to be reduced, stopped or delayed by determining the temperature of the ufSCR. If the temperature of the ufSCR is less than or equal to the temperature threshold, reducing, stopping or delaying the urea injection amount of the ccSCR will increase the content of NOx in the vehicle exhaust. Therefore, before reducing, stopping or delaying the urea injection amount of the ccSCR, it is determined whether the temperature of the ufSCR is less than or equal to the temperature threshold, so that the content of NOx in the vehicle exhaust can be avoided.

[0064] Specifically, the method further comprises: obtaining a corresponding relationship between the temperature of the rear-stage SCR and the conversion efficiency of the rear-stage SCR for NOx; the method further comprises: in the case that the temperature of the rear-stage SCR is greater than the temperature threshold, determining that the conversion efficiency of the rear-stage SCR for NOx is greater than an efficiency threshold, and the efficiency threshold and the temperature threshold satisfy the corresponding relationship.

[0065] The temperature threshold of the ufSCR can be set to 200℃, 230℃, 250℃, or 270℃, or other temperatures.

[0066] Specifically, the conversion efficiency of the ufSCR on NOx is related to temperature, and the temperature of the ufSCR can be continuously adjusted to determine the conversion efficiency of the ufSCR on NOx. When the conversion efficiency of the ufSCR on NOx is greater than the efficiency threshold, the urea injection amount of the ccSCR can be reduced or stopped, wherein the efficiency threshold refers to the case where the urea injection amount of the ccSCR is reduced or stopped, and the ufSCR still plays a dominant role in converting NOx, so that the content of NOx in the exhaust gas does not exceed the standard.

[0067] In order for those skilled in the art to more clearly understand the technical solutions of the present application, the implementation process of the method for preventing the generation of N2O will be described in detail below in conjunction with specific embodiments.

[0068] The present embodiment relates to a specific method for preventing the generation of N2O, which is implemented based on a dual-SCR aftertreatment system, as shown in Figure 3 The system includes a ccSCR 10, a ccASC 20, a DOC 30, a DPF 40, a ufSCR 50, a ufASC 60, a urea nozzle 70, a first urea nozzle 71, a second urea nozzle 72, a NOx sensor 80, a first NOx sensor 81, a second NOx sensor 82, a third NOx sensor 83, a temperature sensor 90, a first temperature sensor 91, a second temperature sensor 92, a third temperature sensor 93, a fourth temperature sensor 94, and a fifth temperature sensor 95.

[0069] Related research shows that the DOC temperature is easy to oxidize NH3 to N2O at 200℃-350℃, and the ccSCR performs ammonia storage and closed-loop injection under low load conditions. When a temperature surge condition is encountered, the NH3 adsorption rate in the ccSCR is lower than the desorption rate, which is easy to cause NH3 leakage. Therefore, it is necessary to add a ccASC, but the ccASC has limited conversion ability for NH3 leakage. Therefore, it is necessary to modify the urea injection of the ccSCR according to temperature, load, and other factors to prevent NH3 leakage downstream of the ccASC, thereby avoiding the oxidation of NH3 leakage through the DOC to generate N2O.

[0070] A specific method for preventing the generation of N2O is shown in Figure 4As shown, first determine whether the temperature rise rate of the ccSCR is greater than the temperature rise rate threshold value, if the temperature rise rate is greater than the temperature rise rate threshold value, the ccSCR is prone to ammonia leakage at this time, at this time, it is necessary to determine whether the ammonia storage θ in the ccSCR is greater than the θ threshold value (the maximum NH3 storage threshold value of the temperature rise rate without NH3 leakage), if it is true, it indicates that the ccSCR faces the risk of NH3 leakage, then determine the temperature range of the DOC, whether the DOC is in the temperature interval prone to oxidizing NH3 to generate N2O, the DOC temperature range includes 200-350°C, but is not limited to 200-350°C, if the DOC temperature is in the temperature interval prone to oxidizing NH3, then determine whether the ufSCR temperature is greater than the temperature threshold value, if the ufSCR temperature is greater than the temperature threshold value at this time, the ufSCR conversion capacity is very strong, which can play a dominant role in converting NOx, and the urea injection of the ccSCR is controlled.

[0071] The ccSCR urea injection control principle is as shown in Figure 5 As shown, first convert the real-time measured NOx upstream of the ccSCR into corresponding NH3, unit g / s, then calculate the ccSCR model to convert the NOx downstream of the ccSCR into corresponding NH3, unit g / s, and convert the feedback value of the actual urea injection upstream of the ccSCR into corresponding NH3, unit g / s; window integration is performed on the NH3 converted upstream of the ccSCR, the NH3 converted downstream of the ccSCR, and the NH3 converted by the actual urea injection upstream of the ccSCR to obtain first, second and third ammonia values, respectively, wherein the window integration time is calibrated according to the actual situation of the test bench; subtract the second ammonia storage value from the first ammonia storage value, and then subtract the third ammonia storage value to obtain the ammonia storage in the ccSCR at this moment, then divide the difference between the ammonia storage in the ccSCR and the ammonia storage threshold value of the ccSCR at this moment by the maximum NH3 conversion amount of the ccASC to obtain the correction value of the urea injection of the ccSCR; wherein the ammonia storage threshold value in the ccSCR and the maximum NH3 conversion amount of the ccASC are related to the temperature, which can be determined according to the temperature to determine the ammonia storage threshold value in the ccSCR and the maximum NH3 conversion amount of the ccASC at this temperature; the obtained correction value is normalized to obtain a normalized correction value, wherein the normalization range is (0, 1), the normalized correction value is multiplied by the actual urea injection amount of the ccSCR to obtain the corrected urea injection amount of the ccSCR, to realize the reduction / injection stop or delay injection of the urea nozzle of the ccSCR; the internal ammonia storage of the ccSCR is detected in real time, and in the case that the internal ammonia storage of the ccSCR is less than the ammonia storage threshold value of the ccSCR, the urea nozzle of the ccSCR is controlled to stop reduction / injection stop or delay injection, and the actual urea injection amount of the ccSCR is restored.

[0072] The embodiment is based on a double-SCR aftertreatment system, and NH3 leakage of the ccSCR caused by a sudden increase in the engine temperature is prevented by logically controlling urea injection of the ccSCR, and the problem that NH3 is oxidized into N2O in the DOC is solved.

[0073] The embodiment of the present application further provides a device for preventing N2O generation. It should be noted that the device for preventing N2O generation of the embodiment of the present application can be used to execute the method for preventing N2O generation provided by the embodiment of the present application. The device is used to realize the above-mentioned embodiment and preferred embodiment, and the description is not repeated. As used below, the term "module" can be a combination of software and / or hardware that realizes a predetermined function. Although the device described in the following embodiment is preferably realized in software, realization in hardware or a combination of software and hardware is also possible and contemplated.

[0074] The device for preventing N2O generation provided by the embodiment of the present application is introduced below.

[0075] Figure 6 is a schematic diagram of the device for preventing N2O generation according to the embodiment of the present application. As shown in Figure 6 , the device comprises:

[0076] The first determination unit 61 is configured to determine whether the real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold value in the case that the temperature rise rate of the front-stage SCR is greater than a temperature rise rate threshold value.

[0077] The front-stage SCR is a ccSCR.

[0078] For example, the temperature of the ccSCR rises by 100℃ in 5s, that is, the temperature rise rate is 20℃ / s, and if the temperature rise rate threshold value is 15℃ / s, the temperature rise rate of the ccSCR is greater than the temperature rise rate threshold value, and the ammonia storage in the ccSCR needs to be determined.

[0079] Specifically, the relationship between the temperature rise rate of the ccSCR and the temperature rise rate threshold value is calculated, so that whether the engine temperature suddenly increases can be determined, and the problem that NH3 leakage of the ccSCR caused by a sudden increase in the engine temperature is prevented.

[0080] The second determination unit 62 is configured to determine whether the temperature of the DOC is in a preset temperature range in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold value.

[0081] The real-time ammonia storage in the ccSCR greater than the ammonia storage threshold value will cause NH3 leakage in the ccSCR.

[0082] The preset temperature range of the DOC is generally 200-350 DEG C, but is not limited to 200-350 DEG C. When the temperature of the DOC is in the temperature range, the NH3 leaked from the ccSCR is converted into N2O.

[0083] The first control unit 63 is configured to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle upstream of the front-stage SCR from injecting, or control the urea nozzle upstream of the front-stage SCR to delay injection, to prevent the generation of N2O due to the NH3 leakage of the front-stage SCR, when the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold.

[0084] The rear-stage SCR is a ufSCR.

[0085] The N2O is a new unconventional pollutant added in the emission regulations.

[0086] Specifically, when the temperature of the ufSCR is greater than the temperature threshold, the conversion capacity of the ufSCR reaches a peak value, and the ufSCR can play a dominant role in converting NOx. Even if the ccSCR is reduced in injection or stopped from injecting, the NOx in the vehicle exhaust can be completely converted, so that the generation of N2O can be prevented, and the vehicle emission can meet the national standards.

[0087] In the embodiment, the first determination unit 61 is configured to determine whether the real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold when the temperature rising rate of the front-stage SCR is greater than a temperature rising rate threshold. The second determination unit 62 is configured to determine whether the temperature of the DOC is in a preset temperature range when the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold. The first control unit 63 is configured to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle upstream of the front-stage SCR from injecting, or control the urea nozzle upstream of the front-stage SCR to delay injection, to prevent the generation of N2O due to the NH3 leakage of the front-stage SCR, when the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold. The embodiment controls the urea injection of the front-stage SCR through a logic based on the double-SCR aftertreatment system, prevents the NH3 leakage of the front-stage SCR due to the sudden increase of the engine temperature, and solves the problem that NH3 is oxidized into N2O in the DOC.

[0088] As an optional solution, the device further includes a first acquisition unit and a second control unit.

[0089] The first acquisition unit is configured to acquire the real-time ammonia storage in the pre-stage SCR again after a first preset time period following the reduction of the injection amount of the urea nozzle upstream of the pre-stage SCR, the stop of injection of the urea nozzle upstream of the pre-stage SCR, or the delayed injection of the urea nozzle upstream of the pre-stage SCR.

[0090] The second control unit is configured to control the injection amount of the urea nozzle of the pre-stage SCR to return to a normal injection amount that meets emission requirements if the acquired real-time ammonia storage is less than the ammonia storage threshold.

[0091] The first preset time period can be 5 minutes, 10 minutes, 15 minutes, etc., and can be selected by a person skilled in the art according to actual needs.

[0092] Specifically, after the injection amount of the urea nozzle upstream of the ccSCR is reduced, stopped, or delayed, the real-time ammonia storage in the ccSCR is acquired again after a preset time period, and is compared with the ammonia storage threshold at this moment. If the real-time ammonia storage is less than the ammonia storage threshold at this moment, it is considered that the ccSCR will not leak NH3, and N2O will not be generated. If the real-time ammonia storage is still greater than the ammonia storage threshold at this moment, the injection amount of the urea nozzle upstream of the ccSCR continues to be reduced, stopped, or delayed until a preset time period, and the real-time ammonia storage in the ccSCR is compared with the ammonia storage threshold at this moment again.

[0093] In an optional solution, the device further comprises a construction unit, a third determination unit, a second acquisition unit, and a fourth determination unit.

[0094] The construction unit is configured to construct an ammonia storage calculation model before determining whether the real-time ammonia storage in the pre-stage SCR is greater than an ammonia storage threshold if the temperature rise rate of the pre-stage SCR is greater than a temperature rise rate threshold. The third determination unit is configured to determine the real-time ammonia storage in the pre-stage SCR by using the ammonia storage calculation model. The second acquisition unit is configured to acquire a current temperature of the pre-stage SCR before determining whether the temperature of the DOC is in a preset temperature range if the real-time ammonia storage in the pre-stage SCR is greater than the ammonia storage threshold. The fourth determination unit is configured to determine the ammonia storage threshold corresponding to the current temperature.

[0095] The ammonia storage calculation model is a ccSCR reaction kinetics model.

[0096] Specifically, the ammonia storage threshold value varies with temperature, and the temperature of the ccSCR needs to be obtained first, and then the ammonia storage threshold value is confirmed according to the temperature of the ccSCR, and the correspondence between the temperature of the ccSCR and the ammonia storage threshold value is stored in the table in advance.

[0097] In an alternative solution, the third determining unit comprises a first obtaining module, a deriving module and a determining module.

[0098] The first obtaining module is configured to obtain the ammonia value converted upstream of the preceding SCR, the ammonia value converted downstream of the preceding SCR and the ammonia value converted by the preceding SCR from the injected urea respectively; the deriving module is configured to perform window integration on a plurality of ammonia values converted upstream of the preceding SCR, a plurality of ammonia values converted downstream of the preceding SCR and a plurality of ammonia values converted by the preceding SCR from the injected urea obtained within a second preset time period, to obtain a first ammonia integral value, a second ammonia integral value and a third ammonia integral value respectively; and the determining module is configured to determine the difference between the first ammonia integral value and an ammonia integral sum value as the real-time ammonia storage in the preceding SCR, the ammonia integral sum value being the sum of the second ammonia integral value and the third ammonia integral value.

[0099] The window integration refers to a process of accumulating and summing data within a period of time. In general, window integration sums data within a certain time range to obtain the total amount or sum within the time period; the window integration time can be calibrated according to the actual situation of the test bench.

[0100] Specifically, the window integration time is adjusted and optimized according to the specific environment and conditions of the test bench. Because the test bench can simulate real road driving conditions, including different speeds, loads and environmental conditions, calibration according to the test bench results can more accurately determine the optimal window integration time to achieve the best performance and fuel economy of the engine and vehicle. Therefore, calibration according to the test bench can ensure that the engine can achieve the best performance and fuel economy in actual driving.

[0101] In an alternative solution, the third determining unit further comprises a first obtaining module, a second obtaining module, a second deriving module and a correcting module.

[0102] The first obtaining module is configured to, after determining the difference between the first ammonia integral value and the ammonia integral value as the real-time ammonia storage amount in the front-stage SCR, obtain an ammonia storage difference value between the real-time ammonia storage amount in the front-stage SCR and the ammonia storage threshold value; the second obtaining module is configured to obtain a maximum ammonia conversion value of the front-stage ASC at a current temperature; the second obtaining module is configured to obtain a ratio of the ammonia storage difference value to the maximum ammonia conversion value of the front-stage ASC; and the correction module is configured to normalize the ratio to obtain a normalized result, and correct the original urea injection amount by using the normalized result, so as to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle upstream of the front-stage SCR from injecting, or control the urea nozzle upstream of the front-stage SCR to delay injection.

[0103] Specifically, the ratio of the ammonia storage difference value of the ccSCR to the maximum ammonia conversion value of the ccASC is normalized, so that a parameter of 0 to 1 can be obtained, and the parameter is multiplied by the original urea injection amount, so that the injection amount of the urea nozzle of the ccSCR can be corrected to prevent ammonia leakage of the ccSCR.

[0104] An optional solution is that the device further comprises a third control unit;

[0105] The third control unit is configured to, in a case where the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is less than or equal to the temperature threshold value, control the injection amount of the urea nozzle to remain unchanged.

[0106] The rear-stage SCR is a ufSCR.

[0107] The device determines whether the urea injection amount of the ccSCR needs to be reduced, stopped or delayed by determining the temperature of the ufSCR. If the temperature of the ufSCR is less than or equal to the temperature threshold value, reducing, stopping or delaying the urea injection amount of the ccSCR will increase the content of NOx in the vehicle exhaust. Therefore, before reducing, stopping or delaying the urea injection amount of the ccSCR, it is determined whether the temperature of the ufSCR is less than or equal to the temperature threshold value, so that the content of NOx in the vehicle exhaust can be prevented from increasing.

[0108] An optional solution is that the device further comprises a third obtaining unit and a fourth determining unit.

[0109] The third acquisition unit is configured to acquire a corresponding relationship between the temperature of the rear SCR and the conversion efficiency of the rear SCR for NOx.

[0110] The temperature threshold of the ufSCR can be set to 200 DEG C, 230 DEG C, 250 DEG C or 270 DEG C or other temperatures.

[0111] Specifically, the conversion efficiency of the ufSCR for NOx is related to temperature, and the temperature of the ufSCR can be continuously adjusted to determine the conversion efficiency of the ufSCR for NOx, and in the case that the conversion efficiency of the ufSCR for NOx is greater than the efficiency threshold, the urea injection amount of the ccSCR can be reduced or stopped, wherein the efficiency threshold refers to the case that the urea injection amount of the ccSCR is reduced or stopped, the ufSCR can still play a dominant role in converting NOx, so that the content of NOx in the exhaust gas will not exceed the standard.

[0112] The device for preventing N2O generation comprises a processor and a memory, the first determination unit, the second determination unit and the first control unit are all stored in the memory as program units, and the corresponding functions are realized by the processor executing the program units stored in the memory. The modules are all located in the same processor, or the modules are located in different processors in any combination.

[0113] The processor comprises a core, and the core retrieves the corresponding program units from the memory. The core can be one or more, and the problem of N2O generation in the double-SCR aftertreatment route that cannot be solved by the prior art solution can be solved by adjusting the core parameters.

[0114] The memory can comprise a non-permanent memory in a computer readable medium, a random access memory (RAM) and / or a non-volatile memory such as a read-only memory (ROM) or a flash memory (flash RAM), and the memory comprises at least one memory chip.

[0115] The embodiment of the present application provides a computer readable storage medium, which comprises a stored program, wherein when the program runs, the device where the computer readable storage medium is located is controlled to execute the method for preventing N2O generation.

[0116] Specifically, the method for preventing N2O generation comprises:

[0117] Step S201, in the case that the temperature rise rate of the front-stage SCR is greater than the temperature rise rate threshold value, determining whether the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage amount threshold value;

[0118] Step S202, in the case that the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage amount threshold value, determining whether the temperature of the DOC is in the preset temperature interval;

[0119] Step S203, in the case that the temperature of the DOC is in the preset temperature interval and the temperature of the rear-stage SCR is greater than the temperature threshold value, reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the injection of the urea nozzle upstream of the front-stage SCR, or controlling the delayed injection of the urea nozzle upstream of the front-stage SCR, to prevent N2O generated by oxidation through the DOC due to NH3 leakage of the front-stage SCR.

[0120] Optionally, after reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the injection of the urea nozzle upstream of the front-stage SCR, or controlling the delayed injection of the urea nozzle upstream of the front-stage SCR, the method further comprises: after a first preset time period, again acquiring the real-time ammonia storage amount inside the front-stage SCR; in the case that the real-time ammonia storage amount again acquired is less than the ammonia storage amount threshold value, controlling the injection amount of the urea nozzle of the front-stage SCR to return to the normal injection amount, the normal injection amount being an injection amount that meets emission requirements.

[0121] Optionally, before determining whether the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage amount threshold value in the case that the temperature rise rate of the front-stage SCR is greater than the temperature rise rate threshold value, the method further comprises: constructing an ammonia storage calculation model; determining the real-time ammonia storage amount inside the front-stage SCR using the ammonia storage calculation model; before determining whether the temperature of the DOC is in the preset temperature interval in the case that the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage amount threshold value, the method further comprises: acquiring the current temperature of the front-stage SCR; determining the ammonia storage amount threshold value corresponding to the current temperature.

[0122] Optionally, determining the real-time ammonia storage amount inside the front-stage SCR using the ammonia storage calculation model comprises: respectively obtaining the ammonia value converted upstream of the front-stage SCR, the ammonia value converted downstream of the front-stage SCR, and the ammonia value converted by the front-stage SCR from injected urea; respectively performing window integration on a plurality of ammonia values converted upstream of the front-stage SCR, a plurality of ammonia values converted downstream of the front-stage SCR, and a plurality of ammonia values converted by the front-stage SCR from injected urea obtained within a second preset time period, to correspondingly obtain a first ammonia integral value, a second ammonia integral value, and a third ammonia integral value; determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage amount inside the front-stage SCR.

[0123] Optionally, after determining the difference between the first ammonia integral value and the ammonia integral value as the real-time ammonia storage amount inside the front-stage SCR, the method further comprises: obtaining an ammonia storage difference value between the real-time ammonia storage amount inside the front-stage SCR and the ammonia storage threshold value; obtaining a maximum ammonia conversion value of the front-stage ASC at the current temperature; obtaining a ratio of the ammonia storage difference value to the maximum ammonia conversion value of the front-stage ASC; performing normalization processing on the ratio to obtain a normalized result, and correcting the original urea injection amount by using the normalized result to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle upstream of the front-stage SCR from injecting, or control the urea nozzle upstream of the front-stage SCR to delay injection.

[0124] Optionally, the method further comprises: in a case where the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is less than or equal to the temperature threshold value, controlling the injection amount of the urea nozzle to remain unchanged.

[0125] Optionally, the method further comprises: obtaining a corresponding relationship between the temperature of the rear-stage SCR and the conversion efficiency of the rear-stage SCR for NOx; and the method further comprises: in a case where the temperature of the rear-stage SCR is greater than the temperature threshold value, determining that the conversion efficiency of the rear-stage SCR for NOx is greater than the efficiency threshold value, and the efficiency threshold value and the temperature threshold value satisfy the corresponding relationship.

[0126] An embodiment of the present application provides a processor for running a program, wherein the program performs the method for preventing N2O generation when running.

[0127] Specifically, the method for preventing N2O generation comprises:

[0128] Step S201: in a case where the temperature rise rate of the front-stage SCR is greater than the temperature rise rate threshold value, determining whether the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage threshold value;

[0129] Step S202: in a case where the real-time ammonia storage amount inside the front-stage SCR is greater than the ammonia storage threshold value, determining whether the temperature of the DOC is in the preset temperature range;

[0130] Step S203: in a case where the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold value, reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the urea nozzle upstream of the front-stage SCR from injecting, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, so as to prevent N2O from being generated by oxidation of NH3 leaked from the front-stage SCR through the DOC.

[0131] Optionally, after reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the injection of the urea nozzle upstream of the front-stage SCR, or controlling the delayed injection of the urea nozzle upstream of the front-stage SCR, the method further comprises: obtaining the real-time ammonia storage in the front-stage SCR again after a first preset time period; in the case that the real-time ammonia storage obtained again is less than the ammonia storage threshold, controlling the injection amount of the urea nozzle of the front-stage SCR to return to the normal injection amount, and the normal injection amount is the injection amount that meets the emission requirements.

[0132] Optionally, before determining whether the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold in the case that the temperature rise rate of the front-stage SCR is greater than the temperature rise rate threshold, the method further comprises: constructing an ammonia storage calculation model; determining the real-time ammonia storage in the front-stage SCR by using the ammonia storage calculation model; before determining whether the temperature of the DOC is in the preset temperature range in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold, the method further comprises: obtaining the current temperature of the front-stage SCR; determining the ammonia storage threshold corresponding to the current temperature.

[0133] Optionally, determining the real-time ammonia storage in the front-stage SCR by using the ammonia storage calculation model comprises: obtaining the ammonia value converted upstream of the front-stage SCR, the ammonia value converted downstream of the front-stage SCR, and the ammonia value converted by the injected urea of the front-stage SCR respectively; performing window integration on the plurality of ammonia values converted upstream of the front-stage SCR, the plurality of ammonia values converted downstream of the front-stage SCR, and the plurality of ammonia values converted by the injected urea of the front-stage SCR obtained within a second preset time period respectively, to obtain a first ammonia integral value, a second ammonia integral value, and a third ammonia integral value respectively; determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage in the front-stage SCR.

[0134] Optionally, after determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage in the front-stage SCR, the method further comprises: obtaining the ammonia storage difference value between the real-time ammonia storage in the front-stage SCR and the ammonia storage threshold; obtaining the maximum ammonia conversion value of the front-stage ASC at the current temperature; obtaining the ratio of the ammonia storage difference value to the maximum ammonia conversion value of the front-stage ASC; performing normalization processing on the ratio to obtain a normalization result, and correcting the original urea injection amount by using the normalization result to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the injection of the urea nozzle upstream of the front-stage SCR, or control the delayed injection of the urea nozzle upstream of the front-stage SCR.

[0135] Optionally, the method further comprises: in the case that the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is less than or equal to the temperature threshold, controlling the injection amount of the urea nozzle to remain unchanged.

[0136] Optionally, the method further comprises: obtaining a correspondence between a temperature of the rear-stage SCR and a conversion efficiency of the rear-stage SCR on NOx; and in a case where the temperature of the rear-stage SCR is greater than a temperature threshold, determining that the conversion efficiency of the rear-stage SCR on NOx is greater than an efficiency threshold, the efficiency threshold and the temperature threshold satisfying the correspondence.

[0137] The embodiment of the present application provides a device, which comprises a processor, a memory, and a program stored in the memory and executable on the processor, and the processor implements at least the following steps when executing the program:

[0138] In a case where the temperature rising rate of the front-stage SCR is greater than a temperature rising rate threshold, determining whether a real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold;

[0139] In a case where the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold, determining whether a temperature of the DOC is in a preset temperature range;

[0140] In a case where the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than a temperature threshold, reducing an injection amount of a urea nozzle upstream of the front-stage SCR, or stopping injection of the urea nozzle upstream of the front-stage SCR, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, so as to prevent N2O generated by oxidation of the DOC due to NH3 leakage of the front-stage SCR.

[0141] The device herein can be a server, a PC, a PAD, a mobile phone, or the like.

[0142] Optionally, after reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping injection of the urea nozzle upstream of the front-stage SCR, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, the method further comprises: obtaining the real-time ammonia storage in the front-stage SCR again after a first preset time period; and in a case where the real-time ammonia storage obtained again is less than the ammonia storage threshold, controlling the injection amount of the urea nozzle of the front-stage SCR to return to a normal injection amount, the normal injection amount being an injection amount meeting an emission requirement.

[0143] Optionally, before determining, in a case where the temperature rising rate of the front-stage SCR is greater than a temperature rising rate threshold, whether a real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold, the method further comprises: constructing an ammonia storage calculation model; determining the real-time ammonia storage in the front-stage SCR by using the ammonia storage calculation model; and before determining, in a case where the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold, whether a temperature of the DOC is in a preset temperature range, the method further comprises: obtaining a current temperature of the front-stage SCR; and determining an ammonia storage threshold corresponding to the current temperature.

[0144] Optionally, the ammonia storage amount in the pre-SCR is determined by using an ammonia storage calculation model, including: obtaining an ammonia value converted upstream of the pre-SCR, an ammonia value converted downstream of the pre-SCR, and an ammonia value converted by the pre-SCR from the injected urea, respectively; performing window integration on the ammonia values converted upstream of the pre-SCR, the ammonia values converted downstream of the pre-SCR, and the ammonia values converted by the pre-SCR from the injected urea obtained in a second preset time period, respectively, to obtain a first ammonia integral value, a second ammonia integral value, and a third ammonia integral value, respectively; determining a difference between the first ammonia integral value and a sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage amount in the pre-SCR.

[0145] Optionally, after determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage amount in the pre-SCR, the method further includes: obtaining an ammonia storage difference between the real-time ammonia storage amount in the pre-SCR and an ammonia storage threshold; obtaining a maximum ammonia conversion value of the pre-ASC at a current temperature; obtaining a ratio of the ammonia storage difference to the maximum ammonia conversion value of the pre-ASC; performing normalization processing on the ratio to obtain a normalized result, and using the normalized result to correct the original urea injection amount to reduce the injection amount of the urea nozzle upstream of the pre-SCR, or stop the urea nozzle upstream of the pre-SCR from injecting, or control the urea nozzle upstream of the pre-SCR to delay injection.

[0146] Optionally, the method further includes: in a case where the temperature of the DOC is in a preset temperature range and the temperature of the post-SCR is less than or equal to a temperature threshold, controlling the injection amount of the urea nozzle to remain unchanged.

[0147] Optionally, the method further includes: obtaining a corresponding relationship between the temperature of the post-SCR and the conversion efficiency of the post-SCR for NOx; the method further includes: in a case where the temperature of the post-SCR is greater than the temperature threshold, determining that the conversion efficiency of the post-SCR for NOx is greater than an efficiency threshold, the efficiency threshold and the temperature threshold satisfying the corresponding relationship.

[0148] The application also provides a computer program product adapted to execute a program initialized with at least the following method steps when executed on a data processing device:

[0149] Step S201, in a case where the temperature rise rate of the pre-SCR is greater than a temperature rise rate threshold, determining whether the real-time ammonia storage amount in the pre-SCR is greater than an ammonia storage threshold;

[0150] Step S202, in a case where the real-time ammonia storage amount in the pre-SCR is greater than the ammonia storage threshold, determining whether the temperature of the DOC is in a preset temperature range;

[0151] Step S203, in the case where the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than the temperature threshold, reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the urea nozzle upstream of the front-stage SCR from injecting, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, to prevent N2O generated by oxidation in the DOC from leaking NH3 to the front-stage SCR.

[0152] It is apparent that those skilled in the art should understand that the modules or steps of the present application described above can be realized by general computing devices, which can be centralized on a single computing device or distributed on a network composed of multiple computing devices, and can be realized by program codes executable by the computing devices, so that they can be stored in storage devices and executed by the computing devices, and in some cases, the steps shown or described can be executed in different orders, or they can be respectively manufactured into individual integrated circuit modules, or multiple modules or steps among them can be manufactured into a single integrated circuit module. Thus, the present application is not limited to any specific combination of hardware and software.

[0153] Those skilled in the art should understand that the embodiments of the present application can be provided as a method, a system, or a computer program product. Therefore, the present application can take the form of an entirely hardware embodiment, an entirely software embodiment, or an embodiment combining software and hardware aspects. Moreover, the present application can take the form of a computer program product implemented on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROMs, optical storage, etc.) containing computer-usable program code.

[0154] The present application is described with reference to flowcharts and / or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the present application. It should be understood that each flow and / or block in the flowcharts and / or block diagrams, as well as combinations of flows and / or blocks in the flowcharts 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, a special-purpose computer, an embedded processor, or other programmable data processing apparatus to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing apparatus produce a means for implementing the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocks Figure 1 The functions specified in a flow or multiple flows and / or blocks

[0155] These computer program instructions can also be stored in a computer-readable memory that can direct the computer or other programmable data processing apparatus to work in a specific manner, so that the instructions stored in the computer-readable memory produce a manufactured product including instruction means, which implements the functions specified in the flowcharts and / or block diagrams. Figure 1 The functions specified in a flow or multiple flows and / or blocksFigure 1 the function(s) specified in the block or blocks.

[0156] These computer program instructions can also be loaded into computer or other programmable data processing devices to cause a series of operational steps to be performed on the computer or other programmable devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable devices provide steps for implementing the flowchart block(s) or flowchart flow(s) and / or portions thereof. Figure 1 the flowchart block(s) or flowchart flow(s) and / or portions thereof. Figure 1 the function(s) specified in the block or blocks.

[0157] In one typical configuration, the computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0158] The memory can include non-persistent memory and / or volatile memory, such as random access memory (RAM) about which the computer stores information such as computer program code and data structures; and non-volatile memory, such as read only memory (ROM), EPROM, EEPROM, or flash memory, about which the computer stores information, such as computer program code and data structures. Memory is an example of computer readable media.

[0159] Computer readable media includes permanent and non-permanent, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Examples of computer storage media include, but are not limited to, phase change memory (PRAM), static random access memory (SRAM), dynamic random access memory (DRAM), other types of random access memory (RAM), read only memory (ROM), electrically erasable programmable read only memory (EEPROM), flash memory or other memory technology, compact disc read only memory (CD-ROM), digital versatile discs (DVD) or other optical storage, magnetic cassettes, magnetic tapes, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible to computing devices. According to the definition herein, computer readable media does not include transitory media, such as modulated data signals and carrier waves.

[0160] It should also be noted that the terms "comprising," "including," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but can also include other elements not expressly listed or inherent to such process, method, article, or apparatus. Without limitation, an element preceded by "comprises a" does not, without more constraints, foreclose the existence of additional identical elements in the process, method, article, or apparatus that comprises the element.

[0161] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0162] 1) A method for preventing the generation of N2O, the method is applied to a controller of a double-SCR aftertreatment system, the double-SCR aftertreatment system further comprises a front-stage SCR, a front-stage ASC, a DOC, a DPF, a rear-stage SCR and a rear-stage ACS connected in sequence, and urea nozzles are installed upstream of the front-stage SCR and upstream of the rear-stage SCR, and the method comprises: determining whether the real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold value in the case that the temperature rise rate of the front-stage SCR is greater than a temperature rise rate threshold value; determining whether the temperature of the DOC is in a preset temperature interval in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold value; and reducing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the urea nozzle upstream of the front-stage SCR from injecting, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, in the case that the temperature of the DOC is in the preset temperature interval and the temperature of the rear-stage SCR is greater than a temperature threshold value, so as to prevent N2O from being generated due to NH3 leakage of the front-stage SCR. Based on the double-SCR aftertreatment system, the urea injection of the front-stage SCR is logically controlled to prevent NH3 leakage of the front-stage SCR caused by a sudden increase in engine temperature, thereby solving the problem of NH3 being oxidized to N2O in the DOC.

[0163] 2) An apparatus for preventing the generation of N2O, the apparatus is applied to a controller of a double-SCR aftertreatment system, the double-SCR aftertreatment system further comprises a front-stage SCR, a front-stage ASC, a DOC, a DPF, a rear-stage SCR and a rear-stage ACS connected in sequence, and urea nozzles are installed upstream of the front-stage SCR and upstream of the rear-stage SCR, and the apparatus comprises: a first determination unit configured to determine whether the real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold value in the case that the temperature rise rate of the front-stage SCR is greater than a temperature rise rate threshold value; a second determination unit configured to determine whether the temperature of the DOC is in a preset temperature interval in the case that the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold value; and a control unit configured to reduce the injection amount of the urea nozzle upstream of the front-stage SCR, or stop the urea nozzle upstream of the front-stage SCR from injecting, or control the urea nozzle upstream of the front-stage SCR to delay injection, in the case that the temperature of the DOC is in the preset temperature interval and the temperature of the rear-stage SCR is greater than a temperature threshold value, so as to prevent N2O from being generated due to NH3 leakage of the front-stage SCR. Based on the double-SCR aftertreatment system, the urea injection of the front-stage SCR is logically controlled to prevent NH3 leakage of the front-stage SCR caused by a sudden increase in engine temperature, thereby solving the problem of NH3 being oxidized to N2O in the DOC.

[0164] The above descriptions are only the preferred embodiments of the present application, and are not intended to limit the present application. The present application can have various modifications and changes for those skilled in the art. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method of preventing N20 generation, the method being applied to a controller of a dual-SCR aftertreatment system, the dual-SCR aftertreatment system further comprising a front-stage SCR, a front-stage ASC, a DOC, a DPF, a rear-stage SCR, and a rear-stage ASC connected in series, and a urea nozzle being installed upstream of the front-stage SCR and upstream of the rear-stage SCR, characterized in that, The method comprises the following steps: determining whether the real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold value when the temperature rise rate of the front-stage SCR is greater than a temperature rise rate threshold value; determining whether the temperature of the DOC is in a preset temperature range when the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold value; decreasing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the urea nozzle upstream of the front-stage SCR from injecting, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, to prevent N2O generated by oxidation through the DOC due to NH3 leakage of the front-stage SCR when the temperature of the DOC is in the preset temperature range and the temperature of the rear-stage SCR is greater than a temperature threshold value; Before determining whether the real-time ammonia storage in the front-stage SCR is greater than an ammonia storage threshold value when the temperature rise rate of the front-stage SCR is greater than a temperature rise rate threshold value, the method further comprises: constructing an ammonia storage calculation model; and determining the real-time ammonia storage in the front-stage SCR by using the ammonia storage calculation model; Before determining whether the temperature of the DOC is in a preset temperature range when the real-time ammonia storage in the front-stage SCR is greater than the ammonia storage threshold value, the method further comprises: obtaining the current temperature of the front-stage SCR; and determining the ammonia storage threshold value corresponding to the current temperature; The method further comprises the following steps: obtaining the ammonia value upstream of the front-stage SCR, the ammonia value downstream of the front-stage SCR and the ammonia value converted by the front-stage SCR respectively; window integrating a plurality of ammonia values upstream of the front-stage SCR, a plurality of ammonia values downstream of the front-stage SCR and a plurality of ammonia values converted by the front-stage SCR obtained in a second preset time period respectively to obtain a first ammonia integral value, a second ammonia integral value and a third ammonia integral value respectively; determining the difference between the first ammonia integral value and the sum of the second ammonia integral value and the third ammonia integral value as the real-time ammonia storage in the front-stage SCR.

2. The method of claim 1, wherein, The method further comprises the following steps: After decreasing the injection amount of the urea nozzle upstream of the front-stage SCR, or stopping the urea nozzle upstream of the front-stage SCR from injecting, or controlling the urea nozzle upstream of the front-stage SCR to delay injection, the method further comprises: obtaining the real-time ammonia storage in the front-stage SCR again after a first preset time period; controlling the injection amount of the urea nozzle of the front-stage SCR to return to a normal injection amount which is an injection amount meeting emission requirements when the real-time ammonia storage obtained again is less than the ammonia storage threshold value.

3. The method of claim 1, wherein, The method further comprises the following steps: obtaining the ammonia storage difference between the real-time ammonia storage in the front-stage SCR and the ammonia storage threshold value; obtaining the maximum ammonia conversion value of the front-stage ASC at the current temperature; obtaining a ratio of the ammonia storage difference and a maximum ammonia conversion value of the preceding ASC; normalizing the ratio to obtain a normalized result, and correcting the original urea injection amount by using the normalized result to reduce the injection amount of the urea nozzle upstream of the preceding SCR, or to stop the urea nozzle upstream of the preceding SCR from injecting, or to control the urea nozzle upstream of the preceding SCR to delay injection.

4. The method of claim 1, wherein, The method further includes: controlling the injection amount of the urea nozzle to remain unchanged when the temperature of the DOC is in the preset temperature range and the temperature of the subsequent SCR is less than or equal to the temperature threshold.

5. The method of claim 1, wherein The method further includes obtaining a corresponding relationship between the temperature of the subsequent SCR and the conversion efficiency of the subsequent SCR for NOx. The method further includes determining that the conversion efficiency of the subsequent SCR for NOx is greater than an efficiency threshold when the temperature of the subsequent SCR is greater than the temperature threshold, the efficiency threshold and the temperature threshold satisfying the corresponding relationship.

6. An apparatus for carrying out the method of any one of claims 1 to 5 for preventing the generation of N20, the apparatus having a controller applied to a dual-SCR aftertreatment system, the dual-SCR aftertreatment system further comprising a front-stage SCR, a front-stage ASC, a DOC, a DPF, a rear-stage SCR and a rear-stage ASC connected in series, and a urea nozzle being installed upstream of the front-stage SCR and upstream of the rear-stage SCR, characterized in that, including: a first determination unit configured to determine whether a real-time ammonia storage amount inside the preceding SCR is greater than an ammonia storage threshold when a temperature rise rate of the preceding SCR is greater than a temperature rise rate threshold; a second determination unit configured to determine whether the temperature of the DOC is in a preset temperature range when the real-time ammonia storage amount inside the preceding SCR is greater than the ammonia storage threshold; a control unit configured to reduce the injection amount of the urea nozzle upstream of the preceding SCR, or to stop the urea nozzle upstream of the preceding SCR from injecting, or to control the urea nozzle upstream of the preceding SCR to delay injection, to prevent N2O generated by oxidation through the DOC due to NH3 leakage of the preceding SCR when the temperature of the DOC is in the preset temperature range and the temperature of the subsequent SCR is greater than a temperature threshold.

7. A computer readable storage medium characterized in that, The computer-readable storage medium includes a stored program, wherein the program controls the device where the computer-readable storage medium is located to execute the method for preventing N2O generation according to any one of claims 1 to 5 when the program is running.

8. An electronic device, comprising: including: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include a program for executing the method for preventing N2O generation according to any one of claims 1 to 5.

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