Urea injection control method and control device for a dual-scr exhaust gas treatment system

Abstract

The application provides a urea injection control method and control device of a double-SCR exhaust treatment system, the method comprising: obtaining a first ammonia storage, an actual ammonia content and first identification information when the DPF is in an active regeneration mode; reducing the first injection amount of the second SCR to make the actual ammonia content less than or equal to the first threshold value when the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, the first injection amount being the injection amount of the urea water solution of the urea nozzle of the second SCR; and reducing the first injection amount of the second SCR to make the first deviation value less than or equal to the second threshold value when the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, the first deviation value being the absolute value of the difference between the first ammonia storage and the actual ammonia content. The method solves the problem of ammonia leakage during active regeneration of the double-SCR exhaust treatment system in the prior art.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of data communication, in particular to a urea injection control method and device for a dual-SCR exhaust treatment system, a computer readable storage medium and an exhaust treatment system. BACKGROUND

[0002] With the tightening of next-generation emission regulations, the current national six post-processing technology route (DOC+DPF+SCR / ASC) is difficult to meet the requirements of next-generation emission regulations, and reducing NOx emissions during engine cold start has become a key work. Currently, major engine manufacturers mainly research dual-SCR (ccSCR\ccASC+DOC+DPF+ufSCR\ufASC) post-processing route, but the cleaning of DPF carbon deposition cannot completely rely on passive regeneration, and active regeneration is still needed. During active regeneration, the hot-state WHTC cycle NOx weighted emission and NH3 leakage still need to meet the emission regulation requirements, which has become a major problem. SUMMARY

[0003] The main purpose of the present application is to provide a urea injection control method, device, computer readable storage medium and exhaust treatment system for a dual-SCR exhaust treatment system, which at least solves the problem of ammonia leakage during active regeneration of the dual-SCR exhaust treatment system in the prior art.

[0004] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a urea injection control method for a dual-SCR exhaust treatment system is provided, the method comprising: in the case that a DPF is in an active regeneration mode, obtaining a first ammonia storage, an actual ammonia content and first identification information, the first ammonia storage being a maximum ammonia storage of urea aqueous solution in a first SCR, the actual ammonia content being an actual ammonia content of the urea aqueous solution in the first SCR, and the first identification information being used to represent a current control mode of the first SCR, the control mode including open-loop control and closed-loop control; in the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than a first threshold value, reducing a first injection amount of a second SCR to make the actual ammonia content less than or equal to the first threshold value, the first injection amount being an injection amount of urea aqueous solution of a urea nozzle of the second SCR; in the case that the first identification information of the first SCR is closed-loop control and a first deviation value is greater than a second threshold value, reducing the first injection amount of the second SCR to make the first deviation value less than or equal to the second threshold value, the first deviation value being an absolute value of a difference between the first ammonia storage and the actual ammonia content.

[0005] Optionally, after the first ammonia storage amount, the actual ammonia content and the first identification information are acquired, the method further comprises: in the case that the first identification information of the first SCR is closed-loop control, the first deviation value is greater than a third threshold value, and a first target temperature is greater than a fourth threshold value, closing the second SCR and reducing a second injection amount of the first SCR to make the first deviation value less than or equal to the third threshold value, the second injection amount being an injection amount of urea water solution of a urea nozzle of the first SCR, and the first target temperature being a temperature of the first SCR.

[0006] Optionally, reducing the first injection amount of the second SCR to make the actual ammonia content less than or equal to the first threshold value comprises: calculating a second deviation value of a difference between the actual ammonia content and the first threshold value, determining a first target content according to the first deviation value, the first target content being a nitrogen oxide content consumed by processing the second deviation value of ammonia; acquiring a second target content and a third target content and calculating a third deviation value of a difference between the second target content and the third target content, the second target content being a content of nitrogen oxide in the exhaust gas before being processed by the second SCR, and the third target content being a content of nitrogen oxide in the exhaust gas after being processed by the second SCR; calculating a first ratio of a ratio between the first injection amount and the third deviation value, calculating a first adjustment amount of a product between the first target content and the first ratio; calculating a third injection amount of a difference between the first injection amount and the first adjustment amount, and controlling the urea nozzle of the second SCR to spray according to the third injection amount.

[0007] Optionally, reducing the first injection amount of the second SCR to make the first deviation value less than or equal to the second threshold value comprises: calculating a fourth deviation value of a difference between the first deviation value and the second threshold value, determining a fourth target content according to the fourth deviation value, the fourth target content being a content of nitrogen oxide consumed by processing the fourth deviation value of ammonia; calculating a second adjustment amount of a product between the fourth target content and the first ratio; calculating a fourth injection amount of a difference between the first injection amount and the second adjustment amount, and controlling the urea nozzle of the second SCR to spray according to the fourth injection amount.

[0008] Optionally, the controlling the urea nozzle of the second SCR to spray according to the third injection amount comprises: obtaining a second target temperature, wherein the second target temperature is a temperature upstream of the DOC; in a case that the second target temperature is less than a sixth threshold value, correcting the third injection amount according to a first preset coefficient to obtain a fifth injection amount, and controlling the urea nozzle of the second SCR to spray according to the fifth injection amount; in a case that the second target temperature is greater than or equal to the sixth threshold value and less than a seventh threshold value, correcting the third injection amount according to a second preset coefficient to obtain a sixth injection amount, and controlling the urea nozzle of the second SCR to spray according to the sixth injection amount; in a case that the second target temperature is greater than or equal to the seventh threshold value, correcting the third injection amount according to a third preset coefficient to obtain a seventh injection amount, and controlling the urea nozzle of the second SCR to spray according to the seventh injection amount.

[0009] Optionally, before the obtaining the first ammonia storage amount, the actual ammonia content and the first identification information, the method further comprises: obtaining a target carbon load, a target pressure difference and a target cumulative mileage, wherein the target carbon load is a carbon load of the DPF predicted according to a DPF carbon load model, the target pressure difference is a pressure difference between an inlet and an outlet of the DPF, and the target cumulative mileage is a cumulative driving mileage from the last time of active regeneration to the current time; in a case that the target carbon load is greater than a first preset value, and / or the target pressure difference is greater than a second preset value, and / or the target cumulative mileage is greater than a third preset value, controlling the DPF to enter an active regeneration mode.

[0010] Optionally, after the reducing the first injection amount of the second SCR, the method further comprises: in a case that the target carbon load is less than the first preset value, the target pressure difference is less than the second preset value, and the target cumulative mileage is less than the third preset value, controlling the DPF to exit the active regeneration mode.

[0011] According to another aspect of the present application, there is provided a device for controlling urea injection of a dual-SCR exhaust treatment system, the device comprising: obtaining a first ammonia storage, an actual ammonia content and a first identification information when a DPF is in an active regeneration mode, the ammonia storage being a maximum ammonia storage of an aqueous urea solution in a first SCR, the actual ammonia content being an actual ammonia content of the aqueous urea solution in the first SCR, the first identification information being used to represent a current control mode of the first SCR, the control mode including an open-loop control and a closed-loop control; reducing a first injection amount of a second SCR to make the actual ammonia content less than or equal to a first threshold value when the first identification information of the first SCR is the open-loop control and the actual ammonia content is greater than the first threshold value, the first injection amount being an injection amount of the aqueous urea solution of a urea injector of the second SCR; and reducing the first injection amount of the second SCR to make a first deviation value less than or equal to a second threshold value when the first identification information of the first SCR is the closed-loop control and the first deviation value is greater than the second threshold value, the first deviation value being an absolute value of a difference between the first ammonia storage and the actual ammonia content.

[0012] According to still another aspect of the present application, there is provided a computer-readable storage medium, the computer-readable storage medium including a stored program, wherein the computer-readable storage medium is caused to perform any of the methods described above when the program is run.

[0013] According to yet another aspect of the present application, there is provided an exhaust treatment system, comprising: 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, the one or more programs including instructions for performing any of the methods described above.

[0014] The technical scheme is applied to the urea injection control method of the double-SCR exhaust treatment system, first, in the case that the DPF is in the active regeneration mode, a first ammonia storage, an actual ammonia content and first identification information are obtained, the first ammonia storage is the maximum ammonia storage of the urea water solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea water solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode includes open-loop control and closed-loop control; then, in the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than a first threshold value, the first injection amount of the second SCR is reduced so that the actual ammonia content is less than or equal to the first threshold value, and the first injection amount is the injection amount of the urea water solution of the urea nozzle of the second SCR; finally, in the case that the first identification information of the first SCR is closed-loop control and a first deviation value is greater than a second threshold value, the first injection amount of the second SCR is reduced so that the first deviation value is less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content. Based on the control mode of the downstream SCR in the double-SCR exhaust treatment system, the judgment method is determined, in the open-loop control, whether the ammonia in the SCR exceeds the standard is judged according to the actual ammonia content in the SCR and the maximum storage of the ammonia in the SCR without releasing ammonia, in the closed-loop control, whether the ammonia exceeds the standard is determined according to the difference between the actual ammonia content in the current SCR and the maximum ammonia storage of the urea water solution in the SCR and the adaptive adjustment ability of the closed-loop control, in the case that the ammonia in the downstream SCR exceeds the standard, the injection amount of the urea water solution of the upstream SCR is controlled to be reduced, more NOx enters the downstream SCR to consume the excess ammonia in the downstream SCR, so that the ammonia leakage is avoided due to the large temperature change of the DPF during the active regeneration and the decrease of the ammonia containing capacity of the SCR, and the problem that the ammonia leakage exists in the double-SCR exhaust treatment system during the active regeneration in the prior art is solved. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 A hardware structure block diagram of a mobile terminal showing a urea injection control method of a double-SCR exhaust treatment system according to an embodiment of the present application is shown;

[0016] Figure 2 A flowchart showing a urea injection control method of a double-SCR exhaust treatment system according to an embodiment of the present application is shown;

[0017] Figure 3 An algorithm flowchart of a urea injection control method of a double-SCR exhaust treatment system according to an embodiment of the present application is shown;

[0018] Figure 4 A flow chart of a urea injection control method of a dual-SCR exhaust treatment system is shown according to an embodiment of the present application.

[0019] Figure 5 A flow chart of a urea injection control method of a dual-SCR exhaust treatment system is shown according to an embodiment of the present application.

[0020] Figure 6 A structural block diagram of a urea injection control device of a dual-SCR exhaust treatment system is shown according to an embodiment of the present application.

[0021] Wherein, the above figures include the following reference signs:

[0022] 102, processor; 104, memory; 106, transmission device; 108, input and output device. DETAILED DESCRIPTION

[0023] 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.

[0024] In order to enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying 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 belong to the scope of protection of the present application.

[0025] 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 a chronological 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 including 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 not clearly listed or inherent to these processes, methods, products or devices.

[0026] As described in the background section, in the prior art, the temperature rises during active regeneration, the ammonia adsorption capacity of the SCR decreases, and more ammonia overflows into the SCR, resulting in ammonia leakage. In order to solve the problem of ammonia leakage in the prior art dual-SCR tail gas treatment system during active regeneration, the embodiments of this application provide a urea injection control method, control device, computer-readable storage medium, and tail gas treatment system for a dual-SCR tail gas treatment system.

[0027] 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.

[0028] The methods and embodiments provided in this application can be executed on a mobile terminal, a computer terminal, or a 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 urea injection control method of a dual SCR exhaust gas treatment system 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.

[0029] 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 device information display method of 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 disposed remotely 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 combinations 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.

[0030] A urea injection control method of a dual SCR exhaust treatment system running on a mobile terminal, a computer terminal or a similar computing device is provided in the embodiments. 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 sequence is shown in the flowchart, in some cases, the steps shown or described can be executed in an order different from that herein.

[0031] Figure 2 is a flowchart of a urea injection control method of a dual SCR exhaust treatment system according to the embodiments of the present application. As shown in Figure 2 , the method comprises the following steps:

[0032] In step S201, in the case that the DPF is in the active regeneration mode, a first ammonia storage amount, an actual ammonia content and first identification information are obtained, the first ammonia storage amount is a maximum ammonia storage amount of the urea aqueous solution in the first SCR, the actual ammonia content is an actual ammonia content of the urea aqueous solution in the first SCR, and the first identification information is used to represent a current control mode of the first SCR, and the control mode includes open loop control and closed loop control.

[0033] Specifically, in the case that the DPF is in the active regeneration mode, the ECU monitors the regeneration request, and to avoid ammonia escaping, the application sets to make a judgment on the ammonia storage of the ufSCR, wherein the ufSCR is the first SCR described above and is located downstream of the exhaust treatment system. The above scheme is specifically to obtain the first identification information to determine the control logic of the ufSCR, that is, the control mode described above. And according to the control mode, the first ammonia storage or the actual ammonia content is collected to make a judgment.

[0034] Step S202, in the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, the first injection amount of the second SCR is reduced to make the actual ammonia content less than or equal to the first threshold value, and the first injection amount is the injection amount of urea solution of the urea nozzle of the second SCR;

[0035] Specifically, as shown in Figure 3 , in the case that the control logic of the ufSCR is open-loop control, that is, the urea nozzle only sprays a set amount of urea solution without closed-loop correction, the actual ammonia content is compared with the preset threshold value, that is, it is determined that the actual ammonia content θ OL is greater than the maximum content of ammonia that can be contained in the ufSCR at the temperature of active regeneration, that is, the first threshold value, to determine that there is a risk of ammonia leakage at present. Further, the application sets to suppress the injection amount of the ccSCR, that is, the second SCR, that is, to reduce the consumption of nitrogen oxides of the second SCR, to release more nitrogen oxides to the first SCR to consume the ammonia of the first SCR.

[0036] Step S203, in the case that the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, the first injection amount of the second SCR is reduced to make the first deviation value less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content.

[0037] Specifically, as shown in Figure 3 , in the case that the control logic of the ufSCR is closed-loop control, that is, the urea injection amount is corrected according to the content of nitrogen oxides, the first ammonia storage and the actual ammonia content, the difference between the first ammonia storage and the actual ammonia content is compared with the second threshold value, that is, it is determined whether the deviation value of the current ammonia content and ammonia storage exceeds the adjustment range of the closed-loop control, and in the case that it exceeds the range, it is determined that there is a risk of ammonia leakage at present. Further, the application sets to suppress the injection amount of the ccSCR, that is, the second SCR, that is, to reduce the consumption of nitrogen oxides of the second SCR, to release more nitrogen oxides to the first SCR to consume the ammonia of the first SCR.

[0038] By the embodiment, first, in the case that the DPF is in the active regeneration mode, a first ammonia storage, an actual ammonia content and first identification information are acquired, the first ammonia storage is the maximum ammonia storage of the urea water solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea water solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode includes open-loop control and closed-loop control; then, in the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than a first threshold value, the first injection amount of the second SCR is reduced to make the actual ammonia content less than or equal to the first threshold value, and the first injection amount is the injection amount of the urea water solution of the urea nozzle of the second SCR; finally, in the case that the first identification information of the first SCR is closed-loop control and a first deviation value is greater than a second threshold value, the first injection amount of the second SCR is reduced to make the first deviation value less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content. Based on the control mode of the downstream SCR in the double-SCR exhaust treatment system, the application determines the judgment method, in the open-loop control, whether the ammonia in the SCR exceeds the standard is judged according to the actual ammonia content in the SCR and the maximum storage of ammonia in the SCR without releasing ammonia, in the closed-loop control, whether the ammonia exceeds the standard is determined according to the difference between the actual ammonia content in the current SCR and the maximum ammonia storage of the urea water solution in the SCR and the adaptive adjustment ability of the closed-loop control, in the case that the ammonia in the downstream SCR exceeds the standard, the injection amount of the urea water solution of the upstream SCR is controlled to be reduced, more NOx enters the downstream SCR to consume the excess ammonia in the downstream SCR, so as to avoid that the ammonia leakage is caused by the decrease of the ammonia containing capacity of the SCR due to the large temperature change when the DPF is actively regenerated, and the ammonia leakage problem of the double-SCR exhaust treatment system in the prior art during the active regeneration is solved.

[0039] To avoid ammonia leakage, in an alternative embodiment, after the first ammonia storage, the actual ammonia content and the first identification information are acquired, the method further includes:

[0040] Step S301, in the case that the first identification information of the first SCR is closed-loop control, the first deviation value is greater than a third threshold value, and a first target temperature is greater than a fourth threshold value, the second SCR is closed and the second injection amount of the first SCR is reduced to make the first deviation value less than or equal to the third threshold value, the second injection amount is the injection amount of the urea water solution of the urea nozzle of the first SCR, and the first target temperature is the temperature of the first SCR.

[0041] Specifically, as Figure 3As shown, in the case that the control mode of the first SCR is closed-loop control, the first deviation value is further compared with a third threshold value, and in the case that the first deviation value is greater than the third threshold value and the first target temperature is greater than a fourth threshold value, i.e. the temperature of the first SCR is relatively high, causing the first ammonia storage to sharply decrease, and only by reducing the consumption of nitrogen oxides of the second SCR, ammonia leakage cannot be inhibited, at this time, the application sets to close the second SCR, and reduces the injection amount of the urea nozzle of the first SCR, so as to consume more ammonia by nitrogen oxides and reduce the source of ammonia to avoid ammonia leakage.

[0042] In order to reduce the consumption of nitrogen oxides of the second SCR to avoid ammonia leakage, as shown, Figure 4 As shown, in an optional embodiment, the step S202 comprises:

[0043] In step S2021, a second deviation value is calculated by the difference between the actual ammonia content and the first threshold value, and a first target content is determined according to the first deviation value, and the first target content is the content of nitrogen oxides consumed by the ammonia consumption of the second deviation value;

[0044] Specifically, the second deviation value is calculated by the difference between the actual ammonia content and the first threshold value, i.e. the amount of ammonia that may be leaked in the first SCR, and then the content of nitrogen oxides consumed by the ammonia consumption of the second deviation value is determined according to the oxidation-reduction reaction to obtain the first target content.

[0045] In step S2022, a second target content and a third target content are obtained, and a third deviation value is calculated by the difference between the second target content and the third target content, the second target content is the content of nitrogen oxides in the exhaust gas before being treated by the second SCR, and the third target content is the content of nitrogen oxides in the exhaust gas after being treated by the second SCR;

[0046] Specifically, the content of nitrogen oxides in the exhaust gas before passing through the second SCR is monitored by a front nitrogen oxide sensor, i.e. the second target content, and then the content of nitrogen oxides in the exhaust gas after passing through the second SCR is obtained by a rear nitrogen oxide sensor, i.e. the third target content. Then the difference between the second target content and the third target content is calculated, i.e. the consumption of nitrogen oxides of the second SCR under the current first injection amount.

[0047] In step S2023, a first ratio is calculated by the ratio of the first injection amount to the third deviation value, and a first adjustment amount is calculated by the product of the first target content and the first ratio;

[0048] Specifically, a ratio of the first injection amount and the third deviation value is calculated to obtain a first proportion, i.e. an injection amount of the urea nozzle of the second SCR for consuming a unit volume of the nitrogen oxide. A product of the first target content and the first proportion is calculated to obtain an injection amount that needs to be reduced for the second SCR.

[0049] In step S2024, a third injection amount is calculated by subtracting the first adjustment amount from the first injection amount, and the urea nozzle of the second SCR is controlled to inject according to the third injection amount.

[0050] Specifically, the target injection amount can be determined according to the current injection amount and the injection amount that needs to be reduced, i.e. the third injection amount is calculated by subtracting the first adjustment amount from the first injection amount, and the urea nozzle of the second SCR is controlled to inject according to the third injection amount.

[0051] In order to reduce the consumption of the nitrogen oxide of the second SCR to avoid ammonia leakage, in an optional embodiment, the step S203 comprises:

[0052] In step S2031, a fourth deviation value is calculated by subtracting the second threshold value from the first deviation value, and a fourth target content is determined according to the fourth deviation value, the fourth target content being a content of the nitrogen oxide consumed by the ammonia gas that processes the fourth deviation value.

[0053] Specifically, the fourth deviation value is calculated by subtracting the second threshold value from the first deviation value, i.e. an amount of the ammonia gas that cannot be consumed by the closed-loop control in the first SCR, and the fourth target content is determined by determining a content of the nitrogen oxide consumed by the ammonia gas that processes the fourth deviation value according to the oxidation-reduction reaction.

[0054] In step S2032, a product of the fourth target content and the first proportion is calculated to obtain a second adjustment amount.

[0055] Specifically, the second adjustment amount is calculated by multiplying the fourth target content and the first proportion, i.e. an injection amount that needs to be reduced for the second SCR.

[0056] In step S2033, a fourth injection amount is calculated by subtracting the second adjustment amount from the first injection amount, and the urea nozzle of the second SCR is controlled to inject according to the fourth injection amount.

[0057] Specifically, the target injection amount can be determined according to the current injection amount and the injection amount that needs to be reduced, i.e. the fourth injection amount is calculated by subtracting the second adjustment amount from the first injection amount, and the urea nozzle of the second SCR is controlled to inject according to the fourth injection amount.

[0058] To further eliminate the influence of the decrease of the ammonia storage caused by the temperature rise due to the active regeneration on the injection amount, in an alternative embodiment, the step S2024 comprises:

[0059] In step S20241, a second target temperature is obtained, and in the case that the second target temperature is less than a sixth threshold value, a fifth injection amount is obtained by correcting the third injection amount according to a first preset coefficient, and the urea nozzle of the second SCR is controlled to inject at the fifth injection amount; the second target temperature is the temperature upstream of the DOC.

[0060] Specifically, in a specific implementation, the sixth threshold value is 250℃, that is, in the exhaust treatment system, in the case that the temperature upstream of the DOC is less than 250℃, the fifth injection amount is obtained by calculating the product of the first preset coefficient and the third injection amount, and the urea nozzle of the second SCR is controlled to inject at the fifth injection amount.

[0061] In step S20242, in the case that the second target temperature is greater than or equal to the sixth threshold value and less than a seventh threshold value, a sixth injection amount is obtained by correcting the third injection amount according to a second preset coefficient, and the urea nozzle of the second SCR is controlled to inject at the sixth injection amount.

[0062] Specifically, in a specific implementation, the seventh threshold value is 280℃, that is, in the exhaust treatment system, in the case that the temperature upstream of the DOC is greater than or equal to 250℃ and less than 280℃, the sixth injection amount is obtained by calculating the product of the second preset coefficient and the third injection amount, and the urea nozzle of the second SCR is controlled to inject at the sixth injection amount.

[0063] In step S20243, in the case that the second target temperature is greater than or equal to the seventh threshold value, a seventh injection amount is obtained by correcting the third injection amount according to a third preset coefficient, and the urea nozzle of the second SCR is controlled to inject at the seventh injection amount.

[0064] Specifically, in a specific implementation, in the exhaust treatment system, in the case that the temperature upstream of the DOC is greater than or equal to 280℃, the seventh injection amount is obtained by calculating the product of the third preset coefficient and the third injection amount, and the urea nozzle of the second SCR is controlled to inject at the seventh injection amount.

[0065] To avoid the carbon load of the DPF exceeding a threshold value and damaging the DPF, in an alternative embodiment, before obtaining the first ammonia storage, the actual ammonia content and the first identification information, the method further comprises:

[0066] Step S401, obtaining a target carbon load, a target pressure difference and a target cumulative mileage, the target carbon load being a carbon load of the DPF predicted according to a DPF carbon load model, the target pressure difference being a pressure difference between an inlet and an outlet of the DPF, and the target cumulative mileage being a cumulative mileage from a last time of active regeneration to a current time;

[0067] Specifically, to ensure the accuracy of the carbon load prediction, the present application sets to predict whether the carbon load is over limit through the DPF carbon load model, the DPF pressure difference and the mileage, i.e., to obtain the target carbon load, the target pressure difference and the target cumulative mileage.

[0068] Step S402, in a case that the target carbon load is greater than a first preset value and / or the target pressure difference is greater than a second preset value and / or the target cumulative mileage is greater than a third preset value, controlling the DPF to enter an active regeneration mode.

[0069] Specifically, to avoid damage to the DPF, the present application sets to take the maximum value among the three prediction methods as the final carbon load, so in a case that any one of the carbon loads obtained by the three methods is greater than a threshold value, active regeneration is performed, specifically, in a case that the target carbon load is greater than the first preset value and / or the target pressure difference is greater than the second preset value and / or the target cumulative mileage is greater than the third preset value, active regeneration is performed.

[0070] To avoid the carbon load of the DPF exceeding the threshold value and damaging the DPF, in an alternative embodiment, after reducing the first injection amount of the second SCR, the method further comprises:

[0071] Step S501, in a case that the target carbon load is less than the first preset value, the target pressure difference is less than the second preset value and the target cumulative mileage is less than the third preset value, controlling the DPF to exit the active regeneration mode.

[0072] Specifically, to avoid damage to the DPF, the present application sets to take the maximum value among the three prediction methods as the final carbon load, so in a case that the carbon loads obtained by the three methods are all less than a threshold value, it is determined that the active regeneration is ended.

[0073] To enable those skilled in the art to have a clearer understanding of the technical solutions of the present application, the implementation process of the urea injection control method of the dual-SCR exhaust treatment system of the present application will be described in detail below in combination with specific embodiments.

[0074] The present embodiment relates to a specific urea injection control method of a dual-SCR exhaust treatment system, as shown in Figure 4 The method comprises the following steps:

[0075] Step S1: When the ufSCR open-loop injection, if the ufSCR ammonia storage model calculates the actual ammonia storage θ OL threshold value θerror OL threshold value, i.e. |θerror|≥θerror OL ≥θ OL阈值 , the ccSCR injects with a smaller ammonia nitrogen ratio, so that more NO x enters the ufSCR to clear the ammonia storage;

[0076] Step S2: When the ufSCR closed-loop injection, it is judged whether the absolute value |θerror| of the ufSCR ammonia storage deviation value (the difference value between the ammonia storage set value and the actual ammonia storage θerror) is greater than the ammonia storage threshold value θerror 阈值1 threshold value, i.e. |θerror|≥θerror x , the ccSCR injects with a smaller ammonia nitrogen ratio, so that more NO 阈值 enters the ufSCR to clear the ammonia storage;

[0077] Step S3: When the ufSCR closed-loop injection, if the ufSCR temperature T1 is greater than the threshold temperature T 阈值 and the ufSCR ammonia storage deviation θerror, |θerror|≥θerror 阈值2 , at this time, the ccSCR injection is prohibited during active regeneration, and the ammonia storage in the ufSCR is cleared by reducing the injection through the ufSCR;

[0078] Step S4: In the above injection amount adjustment process, according to different stages of active regeneration, the temperature of the DOC is different, and the injection amount after reduction is corrected according to different preset coefficients.

[0079] 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 the 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 herein.

[0080] The embodiments of the present application also provide a urea injection control device of a dual SCR exhaust treatment system. It should be noted that the urea injection control device of the dual SCR exhaust treatment system of the embodiments of the present application can be used to execute the urea injection control method for the dual SCR exhaust treatment system provided by the embodiments of the present application. The device is used to realize the above-mentioned embodiments and preferred embodiments, and will not be described again. 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 embodiments is preferably realized in software, hardware, or a combination of software and hardware is also possible and is contemplated.

[0081] The urea injection control device of the dual-SCR exhaust treatment system provided by the embodiment of the present application is introduced below.

[0082] Figure 5 is a structural block diagram of the urea injection control device of the dual-SCR exhaust treatment system according to the embodiment of the present application. As shown in Figure 5 , the device comprises:

[0083] The first acquisition unit 10 is configured to acquire the first ammonia storage, the actual ammonia content and the first identification information when the DPF is in the active regeneration mode, wherein the ammonia storage is the maximum ammonia storage of the urea aqueous solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea aqueous solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode comprises open-loop control and closed-loop control.

[0084] Specifically, when the DPF is in the active regeneration mode, the ECU monitors the regeneration request, and to avoid ammonia escape, the present application sets to make a judgment on the ufSCR ammonia storage, wherein the ufSCR is the first SCR and is located downstream of the exhaust treatment system. Specifically, the first identification information is acquired to determine the control logic of the ufSCR, i.e., the control mode. And according to the control mode, the first ammonia storage or the actual ammonia content is collected for judgment.

[0085] The first control unit 20 is configured to reduce the first injection amount of the second SCR to make the actual ammonia content less than or equal to the first threshold value when the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, and the first injection amount is the injection amount of the urea aqueous solution of the urea nozzle of the second SCR.

[0086] Specifically, as shown in Figure 3 , when the control logic of the ufSCR is open-loop control, i.e., the urea nozzle only injects a set amount of urea aqueous solution without closed-loop correction, the actual ammonia content is compared with the preset threshold value, i.e., the actual ammonia content θ OL is greater than the maximum ammonia content that the ufSCR can accommodate at the temperature of active regeneration, i.e., the first threshold value, to determine that there is a risk of ammonia leakage at present. Further, the present application sets to suppress the injection amount of the ccSCR, i.e., the second SCR, i.e., to reduce the consumption of nitrogen oxides of the second SCR, to release more nitrogen oxides to the first SCR to consume the ammonia of the first SCR.

[0087] The second control unit 30 is configured to reduce the first injection quantity of the second SCR when the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold, so that the first deviation value is less than or equal to the second threshold, wherein the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content.

[0088] Specifically, such as Figure 3 As shown, in the case where the control logic of the aforementioned ufSCR is closed-loop control, meaning the urea injection rate is adjusted based on the nitrogen oxide content, the aforementioned first ammonia reserve, and the actual ammonia content, the difference between the aforementioned first ammonia reserve and the aforementioned actual ammonia content is compared with the aforementioned second threshold to determine whether the deviation between the current ammonia content and the ammonia reserve exceeds the adjustment range of the closed-loop control. If it exceeds the range, it is determined that there is a risk of ammonia leakage. Therefore, this application sets up a mechanism to suppress the injection rate of the ccSCR, i.e., the aforementioned second SCR, thereby reducing the nitrogen oxide consumption of the aforementioned second SCR and releasing more nitrogen oxides into the first SCR, consuming the ammonia of the aforementioned first SCR.

[0089] By the embodiment, the first obtaining unit obtains the first ammonia storage, the actual ammonia content and the first identification information when the DPF is in the active regeneration mode, the first ammonia storage is the maximum ammonia storage of the urea water solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea water solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode includes open-loop control and closed-loop control; the first control unit reduces the first injection amount of the second SCR to make the actual ammonia content less than or equal to the first threshold value when the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, and the first injection amount is the injection amount of the urea water solution of the urea nozzle of the second SCR; the second control unit reduces the first injection amount of the second SCR to make the first deviation value less than or equal to the second threshold value when the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content. Based on the control mode of the downstream SCR in the double-SCR exhaust treatment system, the application determines the judgment method, under the open-loop control, whether the ammonia in the SCR exceeds the standard is determined according to the actual ammonia content in the SCR and the maximum storage of ammonia in the SCR without releasing ammonia, under the closed-loop control, whether the ammonia exceeds the standard is determined according to the difference between the actual ammonia content in the current SCR and the maximum ammonia storage of the urea water solution in the SCR and the adaptive adjustment capability of the closed-loop control, and in the case that the ammonia in the downstream SCR exceeds the standard, the upstream SCR is controlled to reduce the injection amount of the urea water solution, so that more NOx enters the downstream SCR to consume the excess ammonia in the downstream SCR, to avoid the decrease of the ammonia containing capacity of the SCR caused by the large temperature change of the DPF during the active regeneration, and the ammonia leakage, and the application solves the problem of ammonia leakage during the active regeneration of the double-SCR exhaust treatment system in the prior art.

[0090] To avoid ammonia leakage, in an alternative embodiment, the device further comprises:

[0091] The third control unit is configured to, after obtaining the first ammonia storage, the actual ammonia content and the first identification information, close the second SCR and reduce the second injection amount of the first SCR to make the first deviation value less than or equal to the third threshold value when the first identification information of the first SCR is closed-loop control, the first deviation value is greater than the third threshold value, and the first target temperature is greater than the fourth threshold value, the second injection amount is the injection amount of the urea water solution of the urea nozzle of the first SCR, and the first target temperature is the temperature of the first SCR.

[0092] Specifically, as Figure 3In the case that the control mode of the first SCR is closed-loop control, the first deviation value is further compared with a third threshold value, and in the case that the first deviation value is greater than the third threshold value and the first target temperature is greater than a fourth threshold value, that is, the temperature of the first SCR is high, causing the first ammonia storage to sharply decrease, and only by reducing the consumption of nitrogen oxides of the second SCR, ammonia leakage cannot be inhibited, at this time, the application sets the second SCR to be closed, and reduces the injection amount of the urea nozzle of the first SCR, so as to consume more ammonia by nitrogen oxides and reduce the source of ammonia to avoid ammonia leakage.

[0093] In order to reduce the consumption of nitrogen oxides of the second SCR to avoid ammonia leakage, in an optional embodiment, the first control unit comprises:

[0094] A first calculation module is configured to calculate a second deviation value by subtracting the first threshold value from the actual ammonia content, and determine a first target content according to the first deviation value, the first target content being the ammonia consumption of the nitrogen oxides consumed by the second deviation value;

[0095] Specifically, the second deviation value is calculated by subtracting the first threshold value from the actual ammonia content, that is, the amount of ammonia that may be leaked in the first SCR is obtained, and then the first target content is obtained by determining the ammonia consumption of the nitrogen oxides consumed by the second deviation value according to the oxidation-reduction reaction.

[0096] A second calculation module is configured to obtain a second target content and a third target content, and calculate a third deviation value by subtracting the second target content from the third target content, the second target content being the content of nitrogen oxides in the exhaust gas before being treated by the second SCR, and the third target content being the content of nitrogen oxides in the exhaust gas after being treated by the second SCR;

[0097] Specifically, the second target content is monitored by the front nitrogen oxide sensor before the exhaust gas passes through the second SCR, and the third target content is obtained by the rear nitrogen oxide sensor after the exhaust gas passes through the second SCR. Then, the third deviation value is obtained by subtracting the second target content from the third target content, that is, the consumption of nitrogen oxides of the second SCR under the current first injection amount is obtained.

[0098] A third calculation module is configured to calculate a first ratio by dividing the first injection amount by the third deviation value, and calculate a first adjustment amount by multiplying the first target content by the first ratio;

[0099] Specifically, a ratio of the first injection amount and the third deviation value is calculated to obtain a first proportion, i.e. an injection amount of the urea nozzle of the second SCR for consuming a unit volume of the nitrogen oxide. A product of the first target content and the first proportion is calculated to obtain an injection amount that needs to be reduced for the second SCR.

[0100] The fourth calculation module is configured to calculate a difference between the first injection amount and the first adjustment amount to obtain a third injection amount, and control the urea nozzle of the second SCR to inject according to the third injection amount.

[0101] Specifically, the target injection amount can be determined according to the current injection amount and the injection amount that needs to be reduced, i.e. a difference between the first injection amount and the first adjustment amount is calculated to obtain a third injection amount, and the urea nozzle of the second SCR is controlled to inject according to the third injection amount.

[0102] In order to reduce the nitrogen oxide consumption of the second SCR to avoid ammonia leakage, in an optional embodiment, the second control unit comprises:

[0103] The fifth calculation module is configured to calculate a difference between the first deviation value and the second threshold value to obtain a fourth deviation value, and determine a fourth target content according to the fourth deviation value, the fourth target content being a content of the nitrogen oxide consumed by the ammonia consumption that processes the fourth deviation value.

[0104] Specifically, a difference between the first deviation value and the second threshold value is calculated to obtain a fourth deviation value, i.e. an amount of ammonia that cannot be consumed by closed-loop control in the first SCR, and a content of the nitrogen oxide consumed by the ammonia consumption that processes the fourth deviation value is determined according to the oxidation-reduction reaction to obtain the fourth target content.

[0105] The sixth calculation module is configured to calculate a product of the fourth target content and the first proportion to obtain a second adjustment amount.

[0106] Specifically, a product of the fourth target content and the first proportion is calculated to obtain a second adjustment amount, i.e. an injection amount that needs to be reduced for the second SCR.

[0107] The seventh calculation module is configured to calculate a difference between the first injection amount and the second adjustment amount to obtain a fourth injection amount, and control the urea nozzle of the second SCR to inject according to the fourth injection amount.

[0108] Specifically, the target injection amount can be determined according to the current injection amount and the injection amount that needs to be reduced, i.e. a difference between the first injection amount and the second adjustment amount is calculated to obtain a fourth injection amount, and the urea nozzle of the second SCR is controlled to inject according to the fourth injection amount.

[0109] To further eliminate the influence of the decrease of ammonia storage caused by the temperature rise due to active regeneration on the injection amount, in an alternative embodiment, the fourth calculation module comprises:

[0110] an acquisition sub-module, configured to acquire a second target temperature, and in a case where the second target temperature is less than a sixth threshold value, correct the third injection amount according to a first preset coefficient to obtain a fifth injection amount and control the urea nozzle of the second SCR to inject at the fifth injection amount;

[0111] Specifically, in a specific implementation, the sixth threshold value is 250℃, that is, in the exhaust treatment system, in a case where the temperature upstream of the DOC is less than 250℃, the product of the first preset coefficient and the third injection amount is calculated to obtain the fifth injection amount, and the urea nozzle of the second SCR is controlled to inject at the fifth injection amount.

[0112] a first control sub-module, configured to, in a case where the second target temperature is greater than or equal to the sixth threshold value and less than a seventh threshold value, correct the third injection amount according to a second preset coefficient to obtain a sixth injection amount and control the urea nozzle of the second SCR to inject at the sixth injection amount;

[0113] Specifically, in a specific implementation, the seventh threshold value is 280℃, that is, in the exhaust treatment system, in a case where the temperature upstream of the DOC is greater than or equal to 250℃ and less than 280℃, the product of the second preset coefficient and the third injection amount is calculated to obtain the sixth injection amount, and the urea nozzle of the second SCR is controlled to inject at the sixth injection amount.

[0114] a second control sub-module, configured to, in a case where the second target temperature is greater than or equal to the seventh threshold value, correct the third injection amount according to a third preset coefficient to obtain a seventh injection amount and control the urea nozzle of the second SCR to inject at the seventh injection amount.

[0115] Specifically, in a specific implementation, in the exhaust treatment system, in a case where the temperature upstream of the DOC is greater than or equal to 280℃, the product of the third preset coefficient and the third injection amount is calculated to obtain the seventh injection amount, and the urea nozzle of the second SCR is controlled to inject at the seventh injection amount.

[0116] To avoid the carbon load of the DPF exceeding a threshold value and damaging the DPF, in an alternative embodiment, the method further comprises:

[0117] The second acquisition unit is configured to acquire a target carbon load, a target pressure difference and a target cumulative mileage before acquiring the first ammonia reserve, the actual ammonia content and the first identification information, the target carbon load being a carbon load of the DPF predicted according to a DPF carbon load model, the target pressure difference being a pressure difference between the inlet and the outlet of the DPF, and the target cumulative mileage being a cumulative mileage from the last time of active regeneration to the current time.

[0118] Specifically, to ensure the accuracy of the carbon load prediction, the application is configured to predict whether the carbon load is over the limit through the DPF carbon load model, the DPF pressure difference and the mileage, i.e., to acquire the target carbon load, the target pressure difference and the target cumulative mileage.

[0119] The fourth control unit is configured to control the DPF to enter the active regeneration mode when the target carbon load is greater than a first preset value and / or the target pressure difference is greater than a second preset value and / or the target cumulative mileage is greater than a third preset value.

[0120] Specifically, to avoid damage to the DPF, the application is configured to take the maximum value among the three prediction methods as the final carbon load, so that active regeneration is performed when any one of the carbon loads obtained by the three methods is greater than a threshold value, specifically, active regeneration is performed when the target carbon load is greater than a first preset value and / or the target pressure difference is greater than a second preset value and / or the target cumulative mileage is greater than a third preset value.

[0121] To avoid the carbon load of the DPF exceeding the threshold value and damaging the DPF, in an alternative embodiment, the device further comprises:

[0122] The fifth control unit is configured to control the DPF to exit the active regeneration mode when the target carbon load is less than the first preset value, the target pressure difference is less than the second preset value and the target cumulative mileage is less than the third preset value after the first injection amount of the second SCR is reduced.

[0123] Specifically, to avoid damage to the DPF, the application is configured to take the maximum value among the three prediction methods as the final carbon load, so that active regeneration is determined to be ended when the carbon loads obtained by the three methods are all less than a threshold value.

[0124] The urea injection control device of the dual-SCR exhaust treatment system includes a processor and a memory, and the first acquisition unit, the first control unit and the second 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.

[0125] The processor comprises a core, and the core retrieves corresponding program units in the memory. The core can be one or more, and the core parameters are adjusted to avoid ammonia leakage in the exhaust treatment system.

[0126] The memory can comprise a non-permanent memory in a computer readable medium, random access memory (RAM) and / or non-volatile memory such as read-only memory (ROM) or flash memory (flash RAM), and the memory comprises at least one memory chip.

[0127] The embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium comprises a stored program, wherein the program controls a device where the computer readable storage medium is located to execute the urea injection control method of the dual SCR exhaust treatment system when the program runs.

[0128] Specifically, the urea injection control method of the dual SCR exhaust treatment system comprises:

[0129] In step S201, in the case where the DPF is in the active regeneration mode, a first ammonia storage amount, an actual ammonia content and first identification information are obtained, the first ammonia storage amount is a maximum ammonia storage amount of urea aqueous solution in the first SCR, the actual ammonia content is an actual ammonia content of the urea aqueous solution in the first SCR, and the first identification information is used to represent a current control mode of the first SCR, and the control mode comprises open loop control and closed loop control.

[0130] Specifically, in the case where the DPF is in the active regeneration mode, the ECU monitors a regeneration request, and to avoid ammonia escape, the application sets to perform ufSCR ammonia storage amount judgment, wherein the ufSCR is the first SCR and is located downstream of the exhaust treatment system. The specific scheme is to obtain the first identification information to determine the control logic of the ufSCR, that is, the control mode. And according to the control mode, the first ammonia storage amount or the actual ammonia content is collected to make a decision.

[0131] In step S202, in the case where the first identification information of the first SCR is open loop control and the actual ammonia content is greater than a first threshold value, the first injection amount of the second SCR is reduced to make the actual ammonia content less than or equal to the first threshold value, and the first injection amount is the injection amount of urea aqueous solution of the urea nozzle of the second SCR.

[0132] Specifically, as shown in the figure, Figure 3 In the case where the control logic of the ufSCR is open loop control, that is, the urea nozzle only sprays a set amount of urea aqueous solution and does not perform closed loop correction, the actual ammonia content is compared with a preset threshold value, that is, the actual ammonia content θ OLIn the case that the maximum content of ammonia gas that can be accommodated in the ufSCR at a temperature greater than the active regeneration temperature, i.e. the first threshold value, it is determined that there is a risk of ammonia gas leakage. Further, the application sets to inhibit the injection amount of the ccSCR, i.e. the second SCR, i.e. to reduce the consumption of nitrogen oxides of the second SCR, so as to release more nitrogen oxides to the first SCR to consume the ammonia gas of the first SCR.

[0133] In the case that the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, the first injection amount of the second SCR is reduced in step S203 so as to make the first deviation value less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage amount and the actual ammonia content.

[0134] Specifically, as shown in the first embodiment of the application, Figure 3 In the case that the control logic of the ufSCR is closed-loop control, i.e. the urea injection amount is corrected according to the content of nitrogen oxides, the first ammonia storage amount and the actual ammonia content, the difference between the first ammonia storage amount and the actual ammonia content is compared with the second threshold value, i.e. it is determined whether the deviation value of the current ammonia content and ammonia storage amount exceeds the adjustment range of the closed-loop control, and in the case that it exceeds the range, it is determined that there is a risk of ammonia gas leakage. Further, the application sets to inhibit the injection amount of the ccSCR, i.e. the second SCR, i.e. to reduce the consumption of nitrogen oxides of the second SCR, so as to release more nitrogen oxides to the first SCR to consume the ammonia gas of the first SCR.

[0135] The embodiment of the application provides a processor, which is used for running a program, wherein the urea injection control method of the double-SCR exhaust treatment system is executed when the program is running.

[0136] Specifically, the urea injection control method of the double-SCR exhaust treatment system comprises:

[0137] In the case that the DPF is in the active regeneration mode, the first ammonia storage amount, the actual ammonia content and the first identification information are obtained in step S201, the first ammonia storage amount is the maximum ammonia storage amount of the urea aqueous solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea aqueous solution in the first SCR, and the first identification information is used for representing the current control mode of the first SCR, and the control mode comprises open-loop control and closed-loop control.

[0138] Specifically, in the case that the DPF is in the active regeneration mode, the ECU monitors the regeneration request, and to avoid ammonia escaping, the application sets to make a judgment on the ammonia storage of the ufSCR, wherein the ufSCR is the first SCR described above and is located downstream of the exhaust treatment system. The above scheme is specifically to obtain the first identification information to determine the control logic of the ufSCR, that is, the control mode described above. And according to the control mode, the first ammonia storage or the actual ammonia content is collected to make a judgment.

[0139] Step S202, in the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, the first injection amount of the second SCR is reduced to make the actual ammonia content less than or equal to the first threshold value, and the first injection amount is the injection amount of urea solution of the urea nozzle of the second SCR;

[0140] Specifically, as shown in Figure 3 , in the case that the control logic of the ufSCR is open-loop control, that is, the urea nozzle only sprays a set amount of urea solution without closed-loop correction, the actual ammonia content is compared with the preset threshold value, that is, it is determined that the actual ammonia content θ OL is greater than the maximum content of ammonia that can be contained in the ufSCR under the temperature of active regeneration, that is, the first threshold value, to determine that there is a risk of ammonia leakage. Further, the application sets to suppress the injection amount of the ccSCR, that is, the second SCR, that is, to reduce the consumption of nitrogen oxides of the second SCR, to release more nitrogen oxides to the first SCR to consume the ammonia of the first SCR.

[0141] Step S203, in the case that the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, the first injection amount of the second SCR is reduced to make the first deviation value less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content.

[0142] Specifically, as shown in Figure 3 , in the case that the control logic of the ufSCR is closed-loop control, that is, the urea injection amount is corrected according to the content of nitrogen oxides, the first ammonia storage and the actual ammonia content, the difference between the first ammonia storage and the actual ammonia content is compared with the second threshold value, that is, it is determined whether the deviation value of the current ammonia content and ammonia storage exceeds the adjustment range of the closed-loop control, and in the case that it exceeds the range, it is determined that there is a risk of ammonia leakage. Further, the application sets to suppress the injection amount of the ccSCR, that is, the second SCR, that is, to reduce the consumption of nitrogen oxides of the second SCR, to release more nitrogen oxides to the first SCR to consume the ammonia of the first SCR.

[0143] The embodiment of the present application provides a tail gas treatment system, the tail gas treatment system comprising a processor, a memory and a program stored in the memory and executable on the processor, and at least the following steps are implemented when the processor executes the program:

[0144] In step S201, in the case where the DPF is in the active regeneration mode, a first ammonia storage, an actual ammonia content and first identification information are acquired, the first ammonia storage is the maximum ammonia storage of the urea water solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea water solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode comprises open-loop control and closed-loop control.

[0145] Specifically, in the case where the DPF is in the active regeneration mode, the ECU monitors the regeneration request, and in order to avoid ammonia escape, the application sets to perform ufSCR ammonia storage judgment, wherein the ufSCR is the first SCR and is located downstream of the tail gas treatment system. The specific scheme is to acquire the first identification information to determine the control logic of the ufSCR, that is, the control mode. And according to the control mode, the first ammonia storage or the actual ammonia content is collected to make a decision.

[0146] In step S202, in the case where the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than a first threshold value, the first injection amount of the second SCR is reduced to make the actual ammonia content less than or equal to the first threshold value, and the first injection amount is the injection amount of the urea water solution of the urea nozzle of the second SCR.

[0147] Specifically, as shown in Figure 3 In the case where the control logic of the ufSCR is open-loop control, that is, the urea nozzle only sprays a set amount of urea water solution and does not perform closed-loop correction, the actual ammonia content is compared with a preset threshold value, that is, it is determined that the actual ammonia content θ OL is greater than the maximum ammonia content that can be accommodated in the ufSCR at the temperature of the active regeneration, that is, the first threshold value, it is determined that there is a risk of ammonia leakage at present. Further, the application sets to suppress the injection amount of the ccSCR, that is, the second SCR, that is, to reduce the consumption of nitrogen oxides of the second SCR, to release more nitrogen oxides to the first SCR to consume the ammonia in the first SCR.

[0148] In step S203, in the case where the first identification information of the first SCR is closed-loop control and the first deviation value is greater than a second threshold value, the first injection amount of the second SCR is reduced to make the first deviation value less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content.

[0149] Specifically, such as Figure 3 As shown, in the case where the control logic of the aforementioned ufSCR is closed-loop control, meaning the urea injection rate is adjusted based on the nitrogen oxide content, the aforementioned first ammonia reserve, and the actual ammonia content, the difference between the aforementioned first ammonia reserve and the aforementioned actual ammonia content is compared with the aforementioned second threshold to determine whether the deviation between the current ammonia content and the ammonia reserve exceeds the adjustment range of the closed-loop control. If it exceeds the range, it is determined that there is a risk of ammonia leakage. Therefore, this application sets up a mechanism to suppress the injection rate of the ccSCR, i.e., the aforementioned second SCR, thereby reducing the nitrogen oxide consumption of the aforementioned second SCR and releasing more nitrogen oxides into the first SCR, consuming the ammonia of the aforementioned first SCR.

[0150] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0151] Step S201: When the DPF is in active regeneration mode, the first ammonia storage, the actual ammonia content and the first identification information are obtained. The first ammonia storage is the maximum ammonia storage in the urea aqueous solution in the first SCR. The actual ammonia content is the actual ammonia content in the urea aqueous solution in the first SCR. The first identification information is used to characterize the current control mode of the first SCR. The control mode includes open-loop control and closed-loop control.

[0152] Specifically, when the DPF is in active regeneration mode, the ECU detects a regeneration request. To prevent ammonia escape, this application sets up a function to determine the ammonia storage level of the ufSCR, where ufSCR is the aforementioned first SCR located downstream of the exhaust gas treatment system. The specific solution involves obtaining the aforementioned first identification information to determine the control logic of the ufSCR, i.e., the aforementioned control mode. Then, based on the control mode, the aforementioned first ammonia storage level or the aforementioned actual ammonia content is collected for judgment.

[0153] Step S202: When the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold, the first injection amount of the second SCR is reduced so that the actual ammonia content is less than or equal to the first threshold. The first injection amount is the injection amount of urea aqueous solution from the urea nozzle of the second SCR.

[0154] Specifically, such as Figure 3 As shown, when the control logic of the ufSCR is open-loop control, meaning the urea nozzle only sprays a set amount of urea solution without closed-loop correction, the actual ammonia content is compared with a preset threshold to determine the actual ammonia content θ. OLIf the temperature exceeds the maximum ammonia content that the ufSCR can hold (i.e., the aforementioned first threshold) at which active regeneration temperature is exceeded, a risk of ammonia leakage is identified. Therefore, this application sets a method to suppress the injection rate of the ccSCR, i.e., the aforementioned second SCR, thereby reducing the nitrogen oxide consumption of the second SCR and releasing more nitrogen oxides into the first SCR, consuming the ammonia in the first SCR.

[0155] Step S203: When the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold, reduce the first injection amount of the second SCR so that the first deviation value is less than or equal to the second threshold. The first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content.

[0156] Specifically, such as Figure 3 As shown, in the case where the control logic of the aforementioned ufSCR is closed-loop control, meaning the urea injection rate is adjusted based on the nitrogen oxide content, the aforementioned first ammonia reserve, and the actual ammonia content, the difference between the aforementioned first ammonia reserve and the aforementioned actual ammonia content is compared with the aforementioned second threshold to determine whether the deviation between the current ammonia content and the ammonia reserve exceeds the adjustment range of the closed-loop control. If it exceeds the range, it is determined that there is a risk of ammonia leakage. Therefore, this application sets up a mechanism to suppress the injection rate of the ccSCR, i.e., the aforementioned second SCR, thereby reducing the nitrogen oxide consumption of the aforementioned second SCR and releasing more nitrogen oxides into the first SCR, consuming the ammonia of the aforementioned first SCR.

[0157] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0158] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0159] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0160] These computer program instructions can also be stored in a computer readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer readable memory produce an article of manufacture including instructions which implement the function specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0161] The computer program instructions can also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer-implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart block or blocks. Figure 1 one or more flowcharts and / or blocks Figure 1 Figure 1 means for functionally implementing the steps listed in the flowchart block or blocks.

[0162] In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0163] The memory can include non-persistent memory and / or volatile memory, such as a random access memory (RAM) including a cache area for the temporary storage of data. The memory can also include non-volatile memory, such as read only memory (ROM), electrically programmable read only memory (EPROM), or electrically erasable programmable read only memory (EEPROM), for the storage of software that is read during runtime. The memory is an example of computer readable media.

[0164] Computer-readable media includes permanent and non-permanent, movable and non-movable media that can be implemented by any method or technology to store information. The information can be 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 technologies, compact disc read-only memory (CD-ROM), digital versatile disc (DVD) or other optical storage, magnetic cassette, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other non-transmission medium that can be used to store information accessible by a computing device. According to the definition herein, computer-readable media does not include transitory media such as modulated data signals and carriers.

[0165] It should also be noted that the terms "comprising", "including", or any other variant thereof are intended to cover non-exclusive inclusion, so that processes, methods, articles or devices including a series of elements not only include those elements, but also include other elements not explicitly listed, or inherent to such processes, methods, articles or devices. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or device including the element.

[0166] From the above description, it can be seen that the above-mentioned embodiments of the present application achieve the following technical effects:

[0167] 1) The urea injection control method of the dual-SCR exhaust treatment system of the present application, first, in the case that the DPF is in the active regeneration mode, a first ammonia storage, an actual ammonia content and a first identification information are obtained, the first ammonia storage is the maximum ammonia storage of the urea aqueous solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea aqueous solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode includes open-loop control and closed-loop control; then, in the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than a first threshold value, the first injection amount of the second SCR is reduced so that the actual ammonia content is less than or equal to the first threshold value, and the first injection amount is the injection amount of the urea aqueous solution of the urea nozzle of the second SCR; finally, in the case that the first identification information of the first SCR is closed-loop control and the first deviation value is greater than a second threshold value, the first injection amount of the second SCR is reduced so that the first deviation value is less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content. Based on the control mode of the downstream SCR in the dual-SCR exhaust treatment system, the present application determines the judgment method, under open-loop control, whether the ammonia in the SCR exceeds the standard is determined by the actual ammonia content in the SCR and the maximum storage of ammonia in the SCR without releasing ammonia, under closed-loop control, whether the ammonia exceeds the standard is determined according to the difference between the actual ammonia content in the current SCR and the maximum ammonia storage of the urea aqueous solution in the SCR and the adaptive adjustment ability of the closed-loop control, in the case that the ammonia in the downstream SCR exceeds the standard, the upstream SCR is controlled to reduce the injection amount of the urea aqueous solution, so that more NOx enters the downstream SCR to consume the excess ammonia in the downstream SCR, to avoid the decrease of the ammonia containing capacity of the SCR caused by the large temperature change during the active regeneration of the DPF, leading to ammonia leakage, the present application solves the problem of ammonia leakage during the active regeneration of the dual-SCR exhaust treatment system in the prior art.

[0168] 2) The urea injection control device of the dual-SCR exhaust treatment system of the application, the first acquisition unit acquires the first ammonia storage, the actual ammonia content and the first identification information when the DPF is in the active regeneration mode, the first ammonia storage is the maximum ammonia storage of the urea solution in the first SCR, the actual ammonia content is the actual ammonia content of the urea solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode includes open-loop control and closed-loop control; the first control unit reduces the first injection amount of the second SCR to make the actual ammonia content less than or equal to the first threshold value when the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, and the first injection amount is the injection amount of the urea solution of the urea nozzle of the second SCR; the second control unit reduces the first injection amount of the second SCR to make the first deviation value less than or equal to the second threshold value when the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content. Based on the control mode of the downstream SCR in the dual-SCR exhaust treatment system, the application determines the judgment method, under open-loop control, whether the ammonia in the SCR exceeds the standard is determined by the actual ammonia content in the SCR and the maximum storage of ammonia in the SCR without releasing ammonia, under closed-loop control, whether the ammonia exceeds the standard is determined according to the difference between the actual ammonia content in the current SCR and the maximum ammonia storage of the urea solution in the SCR and the adaptive adjustment capability of the closed-loop control, and in the case that the ammonia in the downstream SCR exceeds the standard, the upstream SCR is controlled to reduce the injection amount of the urea solution, so that more NOx enters the downstream SCR to consume the excess ammonia in the downstream SCR, to avoid the decrease of the ammonia containing capacity of the SCR caused by the large temperature change of the DPF during active regeneration, leading to ammonia leakage. The application solves the problem of ammonia leakage during active regeneration of the dual-SCR exhaust treatment system in the prior art.

[0169] The above only describes the preferred embodiments of the application and is not intended to limit the application. Those skilled in the art can make various modifications and changes to the application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the application shall be included in the protection scope of the application.

Claims

1. A method of urea injection control for a dual SCR exhaust treatment system, the method comprising: The method comprises: In the case that the DPF is in the active regeneration mode, a first ammonia storage, an actual ammonia content and first identification information are acquired, the first ammonia storage is the maximum ammonia gas storage of the urea water solution in the first SCR, the actual ammonia content is the actual ammonia gas content of the urea water solution in the first SCR, and the first identification information is used to represent the current control mode of the first SCR, and the control mode comprises open-loop control and closed-loop control; In the case that the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than a first threshold value, a first injection amount of the second SCR is reduced so that the actual ammonia content is less than or equal to the first threshold value, and the first injection amount is the injection amount of the urea water solution of the urea nozzle of the second SCR; In the case that the first identification information of the first SCR is closed-loop control and a first deviation value is greater than a second threshold value, the first injection amount of the second SCR is reduced so that the first deviation value is less than or equal to the second threshold value, and the first deviation value is the absolute value of the difference between the first ammonia storage and the actual ammonia content; After the first ammonia storage, the actual ammonia content and the first identification information are acquired, the method further comprises: In the case that the first identification information of the first SCR is closed-loop control, the first deviation value is greater than a third threshold value and a first target temperature is greater than a fourth threshold value, the second SCR is closed and a second injection amount of the first SCR is reduced so that the first deviation value is less than or equal to the third threshold value, the second injection amount is the injection amount of the urea water solution of the urea nozzle of the first SCR, and the first target temperature is the temperature of the first SCR. The first SCR is a downstream SCR, and the second SCR is an upstream SCR.

2. The method of claim 1, wherein, The first injection amount of the second SCR is reduced so that the actual ammonia content is less than or equal to the first threshold value, comprising: A second deviation value is calculated by calculating the difference between the actual ammonia content and the first threshold value, a first target content is determined according to the second deviation value, and the first target content is the nitrogen oxide content of the ammonia gas consumption for processing the second deviation value; A third deviation value is calculated by calculating the difference between a second target content and a third target content, the second target content is the content of the nitrogen oxide in the exhaust gas before being processed by the second SCR, and the third target content is the content of the nitrogen oxide in the exhaust gas after being processed by the second SCR; A first proportion is calculated by calculating the ratio of the first injection amount to the third deviation value, and a first adjustment amount is calculated by calculating the product of the first target content and the first proportion; A third injection amount is calculated by calculating the difference between the first injection amount and the first adjustment amount, and the urea nozzle of the second SCR is controlled to spray according to the third injection amount.

3. The method of claim 2, wherein, The first injection amount of the second SCR is reduced so that the first deviation value is less than or equal to the second threshold value, comprising: A fourth deviation value is calculated by subtracting the second threshold value from the first deviation value, and a fourth target content is determined according to the fourth deviation value, the fourth target content being a content of nitrogen oxides consumed by ammonia in processing the fourth deviation value; A second adjustment amount is calculated by multiplying the fourth target content by the first ratio; A fourth injection amount is calculated by subtracting the second adjustment amount from the first injection amount, and the urea nozzle of the second SCR is controlled to inject according to the fourth injection amount.

4. The method of claim 2, wherein, The urea nozzle of the second SCR is controlled to inject according to the third injection amount, including: A second target temperature is obtained, and in a case where the second target temperature is less than a sixth threshold value, a fifth injection amount is obtained by correcting the third injection amount according to a first preset coefficient, and the urea nozzle of the second SCR is controlled to inject according to the fifth injection amount, the second target temperature being a temperature upstream of the DOC; In a case where the second target temperature is greater than or equal to the sixth threshold value and less than a seventh threshold value, a sixth injection amount is obtained by correcting the third injection amount according to a second preset coefficient, and the urea nozzle of the second SCR is controlled to inject according to the sixth injection amount; In a case where the second target temperature is greater than or equal to the seventh threshold value, a seventh injection amount is obtained by correcting the third injection amount according to a third preset coefficient, and the urea nozzle of the second SCR is controlled to inject according to the seventh injection amount.

5. The method of claim 1, wherein, Before obtaining the first ammonia storage amount, the actual ammonia content and the first identification information, the method further includes: A target carbon load, a target pressure difference and a target cumulative mileage are obtained, the target carbon load being a carbon load of the DPF predicted according to a DPF carbon load model, the target pressure difference being a pressure difference between the inlet and the outlet of the DPF, and the target cumulative mileage being a cumulative driving mileage from the last time of active regeneration to the current time; In a case where the target carbon load is greater than a first preset value, and / or the target pressure difference is greater than a second preset value, and / or the target cumulative mileage is greater than a third preset value, the DPF is controlled to enter an active regeneration mode.

6. The method of claim 5, wherein, After reducing the first injection amount of the second SCR, the method further includes: In a case where the target carbon load is less than the first preset value, the target pressure difference is less than the second preset value, and the target cumulative mileage is less than the third preset value, the DPF is controlled to exit the active regeneration mode.

7. A urea injection control device for a dual-SCR exhaust treatment system for performing the method of any one of claims 1 to 6, characterized in that The device includes: A first obtaining unit is configured to, in a case where the DPF is in an active regeneration mode, obtain a first ammonia storage amount, an actual ammonia content and first identification information, the first ammonia storage amount being a maximum ammonia storage amount of urea solution in the first SCR, the actual ammonia content being an actual ammonia content of the urea solution in the first SCR, and the first identification information being used to represent a current control mode of the first SCR, the control mode including open-loop control and closed-loop control; The first control unit is configured to decrease the first injection amount of the second SCR to make the actual ammonia content less than or equal to the first threshold value, in a case where the first identification information of the first SCR is open-loop control and the actual ammonia content is greater than the first threshold value, the first injection amount being an injection amount of urea water solution of a urea nozzle of the second SCR; The second control unit is configured to decrease the first injection amount of the second SCR to make the first deviation value less than or equal to the second threshold value, in a case where the first identification information of the first SCR is closed-loop control and the first deviation value is greater than the second threshold value, the first deviation value being an absolute value of a difference between the first ammonia storage amount and the actual ammonia content.

8. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein the program, when executed, controls a device in which the computer-readable storage medium is located to perform the method of any one of claims 1 to 6.

9. An off-gas treatment system characterized by, comprising: one or more processors, 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, the one or more programs including programs for performing the method of any one of claims 1 to 6.

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