Control method and device of SCR system, storage medium and system

Abstract

The invention provides a control method and device of an SCR system, a storage medium and the system.The method comprises the steps that the mass flow rate of NOx at the front end of an SCRF is obtained, the first mass flow rate is obtained, and whether the actual conversion efficiency of the SCRF is obtained or not is determined according to the size of the first mass flow rate; the mass flow rate of NOx at the front end of the SCR is obtained, a second mass flow rate is obtained, and whether the actual conversion efficiency of the SCR is obtained or not is determined according to the size of the second mass flow rate; obtaining the current carbon loading capacity, and updating the current active regeneration mode; and after the current active regeneration mode is updated, the urea injection rate of the first urea injection equipment and / or the urea injection rate of the second urea injection equipment are / is adjusted according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR. The SCR system solves the problem that the conversion efficiency of the SCR system is poor due to the fact that efficient heat management is difficult to conduct due to the fact that an existing SCR system is complex.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of engine aftertreatment control, in particular to a control method of an SCR system, a control device of an SCR system, a computer readable storage medium and an SCR system. BACKGROUND

[0002] Diesel engines are widely used in heavy vehicles and engineering machinery due to their high efficiency, reliability and durability. However, the nitrogen oxides (NOx) and particulate matter (PM) emitted by diesel engines have a negative impact on the environment and human health. Although the combination of traditional aftertreatment technologies such as DOC (oxidation catalytic converter), DPF (particulate matter trap) and SCR (selective catalytic reduction device) can handle NOx and PM respectively, there are problems such as complex system, large volume, high cost and difficult thermal management.

[0003] That is, the existing SCR system is difficult to perform efficient thermal management due to its complex system, resulting in poor conversion efficiency of the SCR system. SUMMARY

[0004] The main purpose of the present application is to provide a control method of an SCR system, a control device of an SCR system, a computer readable storage medium and an SCR system to at least solve the problem that the conversion efficiency of the existing SCR system is poor due to the difficulty of efficient thermal management of the complex system.

[0005] In order to achieve the above-mentioned purpose, according to one aspect of the present application, a control method of an SCR system is provided, which is applied to a controller in the SCR system, the SCR system further comprising an SCRF, an SCR, a first urea injection device and a second urea injection device, the first urea injection device being installed to the front end of the SCRF, the second urea injection device being installed to the rear end of the SCRF, the rear end of the SCRF being in communication with the front end of the SCR, the SCRF being an SCR with a SCR catalyst coated on a DPF, comprising: obtaining the mass flow of NOx at the front end of the SCRF to obtain a first mass flow, and determining whether to obtain the actual conversion efficiency of the SCRF according to the size of the first mass flow; obtaining the mass flow of NOx at the front end of the SCR to obtain a second mass flow, and determining whether to obtain the actual conversion efficiency of the SCR according to the size of the second mass flow; obtaining the current carbon load, and updating the current active regeneration mode to a high-temperature active regeneration mode or a low-temperature active regeneration mode according to the size of the current carbon load; after updating the current active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR.

[0006] Optionally, in the case that the current active regeneration mode is the low-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is greater than or equal to an SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to an SCR conversion efficiency limit value, increasing the urea injection rate of the second urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0007] Optionally, in the case that the current active regeneration mode is the high-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is greater than or equal to an SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to an SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0008] Optionally, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is less than a SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than a SCR conversion efficiency limit value, controlling the first urea injection device and the second urea injection device to stop injection work, switching the operation mode of the SCR system to a NOx low original emission mode, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0009] Optionally, before adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, the method further comprises: determining a corresponding SCRF conversion efficiency limit value according to the actual conversion efficiency of the SCRF; determining a corresponding SCR conversion efficiency limit value according to the actual conversion efficiency of the SCR.

[0010] Optionally, determining a corresponding SCRF conversion efficiency limit value according to the actual conversion efficiency of the SCRF comprises: determining a corresponding SCRF conversion efficiency limit value according to a conversion efficiency mapping relationship and the actual conversion efficiency of the SCRF, the conversion efficiency mapping relationship being a mapping relationship between the actual conversion efficiency of the SCRF and the SCRF conversion efficiency limit value; or using a neural network model to process the actual conversion efficiency of the SCRF to obtain the SCRF conversion efficiency limit value.

[0011] Optionally, the method further comprises: obtaining the front-rear end pressure difference of the SCRF; in the case that the front-rear end pressure difference of the SCRF is greater than a pressure difference threshold value and / or the current carbon loading is less than 0, controlling the first urea injection device and the second urea injection device to stop injection work, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0012] According to another aspect of the present application, there is provided a control device of an SCR system, the SCR system further comprising a SCRF, an SCR, a first urea injection device and a second urea injection device, the first urea injection device being installed to a front end of the SCRF, the second urea injection device being installed to a rear end of the SCRF, the rear end of the SCRF being communicated with a front end of the SCR, the SCRF being an SCR with a DPF coated with an SCR catalyst, the control device comprising: a first acquisition unit configured to acquire a mass flow of NOx at the front end of the SCRF to obtain a first mass flow, and determine whether to acquire an actual conversion efficiency of the SCRF according to a size of the first mass flow; a second acquisition unit configured to acquire a mass flow of NOx at the front end of the SCR to obtain a second mass flow, and determine whether to acquire an actual conversion efficiency of the SCR according to a size of the second mass flow; a third acquisition unit configured to acquire a current carbon loading, and update a current active regeneration mode to a high-temperature active regeneration mode or a low-temperature active regeneration mode according to a size of the current carbon loading; and a processing unit configured to adjust a urea injection rate of the first urea injection device and / or a urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR after updating the current active regeneration mode.

[0013] According to yet another aspect of the present application, there is provided a computer readable storage medium comprising a stored program, wherein the computer readable storage medium is caused to perform any of the methods described above when the program is run.

[0014] According to another aspect of the present application, there is provided an SCR system, comprising: a SCRF, an SCR, a first urea injection device, a second urea injection device and a controller, the first urea injection device being installed to a front end of the SCRF, the second urea injection device being installed to a rear end of the SCRF, the rear end of the SCRF being communicated with a front end of the SCR, the SCRF being an SCR with a DPF coated with an SCR catalyst, the controller being in communication with the first urea injection device and the second urea injection device respectively, the controller being configured to perform any of the methods described above.

[0015] The technical solution of the application realizes intelligent adjustment of the working state of the urea injection equipment by monitoring the NOx mass flow of the SCRF front end and the SCR front end and the carbon load of the DPF. The low-temperature active regeneration mode and the high-temperature active regeneration mode are automatically switched according to the carbon load. The low-temperature active regeneration mode is suitable for the case of low carbon load and can realize efficient regeneration under limited heat conditions; and the high-temperature active regeneration mode is aimed at the removal of stubborn deposits when the carbon load is high, and ensures the sufficiency of DPF regeneration. In different regeneration modes, the injection rates of the first urea injection equipment installed at the SCRF front end and the second urea injection equipment installed at the SCRF rear end are dynamically adjusted, so as to realize fine control of NOx treatment. In the low-temperature active regeneration mode, by reducing the demand conversion efficiency of the SCRF, the N amount entering the DPF can be increased, and the passive regeneration efficiency of the DPF can be improved; and in the high-temperature active regeneration mode, by increasing the demand conversion efficiency of the SCRF, the dependence on additional heat is reduced while ensuring the NOx conversion demand, the DPF overheating is avoided, and the safety of thermal management is improved. As can be seen, by intelligent detection of the carbon load and dynamic switching of the regeneration mode, combined with fine control of the urea injection rate, the method not only effectively solves the problem of thermal management of the SCRF system, but also significantly improves the NOx conversion efficiency of the SCRF and the SCR, can continuously maintain high conversion efficiency under complex working conditions and environmental conditions, reduces NOx emission, meets more stringent environmental protection requirements, and solves the problem of poor conversion efficiency of the SCR system in the prior art due to the complexity of the system, which makes it difficult to perform efficient thermal management. BRIEF DESCRIPTION OF DRAWINGS

[0016] The drawings accompanying the specification of the present application form a part thereof, serve to provide further understanding of the present application, and together with the specification explain the application. The use of the same reference numbers in different drawings indicates similar or identical components.

[0017] Figure 1 A flowchart of a control method of an SCR system according to an embodiment of the present application is shown;

[0018] Figure 2 A structural diagram of an SCR system according to an embodiment of the present application is shown;

[0019] Figure 3 A flowchart of a low-temperature active regeneration mode in a control method of an SCR system according to an embodiment of the present application is shown;

[0020] Figure 4 A flowchart of a high-temperature active regeneration mode in a control method of an SCR system according to an embodiment of the present application is shown;

[0021] Figure 5 Fig. 4 shows a flowchart of the low-temperature active regeneration mode in the control method of the SCR system according to an embodiment of the present application;

[0022] Figure 6 Fig. 5 shows a flowchart of the high-temperature active regeneration mode in the control method of the SCR system according to an embodiment of the present application;

[0023] Figure 7 Fig. 6 shows a structural block diagram of a control device of the SCR system according to an embodiment of the present application.

[0024] In the above drawings, the following reference signs apply:

[0025] 100, SCRF; 200, SCR; 300, first urea injection device; 400, second urea injection device; 500, oxidation catalytic converter; 600, ammonia slip catcher; 700, first temperature sensor; 710, second temperature sensor; 720, third temperature sensor; 800, first nitrogen oxide sensor; 810, second nitrogen oxide sensor; 820, third nitrogen oxide sensor; 900, differential pressure sensor. DETAILED DESCRIPTION

[0026] 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 drawings and in combination with the embodiments.

[0027] In order to enable persons skilled in the art to better understand the schemes of the present application, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by persons skilled in the art without creative labor should belong to the scope of protection of the present application.

[0028] It should be noted that the terms "first", "second" and the like in the specification and claims of the present application and the above 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 "comprise" and "have" and any variations thereof are intended to cover non-exclusive inclusion, for example, a process, method, system, product or device comprising a series of steps or units does not necessarily limit 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.

[0029] As introduced in the background, the SCR system in the prior art is difficult to be efficiently heat managed due to the complexity of the system, thereby leading to poor conversion efficiency of the SCR system. To solve the above technical problems, embodiments of the present application provide a control method of an SCR system, a control device of an SCR system, a computer readable storage medium and an SCR system.

[0030] The technical solutions in the embodiments of the present application will be clearly and completely described in the following with reference to the drawings in the embodiments of the present application.

[0031] Figure 1 is a flow chart of the control method of the SCR system according to the embodiments of the present application. Figure 2 is a structural schematic diagram of the SCR system, as Figure 2 shown, the SCR system comprises an SCRF 100, an SCR 200, a first urea injection device 300 and a second urea injection device 400, the first urea injection device 300 is installed to the front end of the SCRF 100, the second urea injection device 400 is installed to the rear end of the SCRF 100, the rear end of the SCRF 100 is communicated with the front end of the SCR 200, the SCRF 100 is the SCR 200 with the SCR catalyst coated on the DPF, as Figure 1 shown, the method comprises the following steps:

[0032] Step S101, obtaining the mass flow of NOx at the front end of the SCRF 100 (a device with a catalyst layer coated on a particulate trap), obtaining a first mass flow, and determining whether to obtain the actual conversion efficiency of the SCRF 100 according to the size of the first mass flow;

[0033] Specifically, the mass flow of NOx in the exhaust gas is collected by the NOx sensor arranged at the front end of the SCRF to obtain the first mass flow; the actual conversion efficiency of the SCRF is calculated once when the cumulative flow exceeds the preset limit value; if the limit value is not reached, the conversion efficiency is not calculated, and only the data is accumulated.

[0034] Step S102, obtaining the mass flow of NOx at the front end of the SCR 200, obtaining a second mass flow, and determining whether to obtain the actual conversion efficiency of the SCR 200 according to the size of the second mass flow;

[0035] Specifically, the mass flow of NOx in the exhaust gas is collected by the NOx sensor arranged at the front end of the SCR to obtain the second mass flow; the actual conversion efficiency of the SCR 200 is calculated once when the cumulative flow exceeds another preset limit value; if the limit value is not reached, the original efficiency data is maintained and the condition is waited for.

[0036] Step S103, obtaining the current carbon load, and updating the current active regeneration mode to a high-temperature active regeneration mode or a low-temperature active regeneration mode according to the size of the current carbon load;

[0037] Specifically, the current carbon load is obtained from the carbon load sensor in the DPF or the SCRF; wherein the low-temperature active regeneration mode represents enhancing passive regeneration at low temperature by increasing the content of nitrogen dioxide, which is suitable for slight blockage; and the high-temperature active regeneration mode represents burning soot by heating, which is suitable for serious blockage, but has higher energy consumption and risk.

[0038] Step S104, after updating the current active regeneration mode, adjusting the urea injection rate of the first urea injection device 300 and / or the urea injection rate of the second urea injection device 400 according to the actual conversion efficiency of the SCRF 100 and the actual conversion efficiency of the SCR 200.

[0039] Specifically, the first urea injection device is arranged at the inlet of the SCRF, i.e. in the pipeline before the engine exhaust enters the SCRF after passing through the oxidation catalyst; and the second urea injection device is arranged in the pipeline between the SCR and the SCRF, i.e. between the outlet of the SCRF and the inlet of the rear SCR.

[0040] Through the above embodiment, by monitoring the mass flow of NOx at the front end of the SCRF and the front end of the SCR, and the carbon load of the DPF, intelligent adjustment of the working state of the urea injection device is realized. According to the high and low of the carbon load, the low-temperature active regeneration mode and the high-temperature active regeneration mode are automatically switched. The low-temperature active regeneration mode is suitable for the case of low carbon load, and can realize efficient regeneration under limited heat conditions; and the high-temperature active regeneration mode is aimed at the removal of stubborn deposits when the carbon load is high, to ensure the sufficiency of DPF regeneration. Under different regeneration modes, the injection rates of the first urea injection device installed at the front end of the SCRF and the second urea injection device installed at the rear end of the SCRF are dynamically adjusted, so as to realize fine control of NOx treatment. Under the low-temperature active regeneration mode, by reducing the required conversion efficiency of the SCRF, the N The method can effectively solve the problem of heat management of the SCR system in the prior art, and significantly improve the NOx conversion efficiency of the SCRF and the SCR, so that the method can continuously maintain a high conversion efficiency under complex working conditions and environmental conditions, reduce NOx emissions, meet more stringent environmental protection requirements, and solve the problem of poor conversion efficiency of the SCR system due to the complexity of the system in the prior art.

[0041] In an alternative, as shown in FIG. 2, in the case where the current active regeneration mode is the low-temperature active regeneration mode, the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device is adjusted according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, including: Figure 3

[0042] Step S201, in the case where the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the second urea injection device;

[0043] Step S202, in the case where the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device;

[0044] Step S203, in the case where the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0045] In the low-temperature active regeneration mode in the above embodiment, by simultaneously monitoring the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, and dynamically adjusting the injection rates of the first urea injection device arranged at the inlet of the SCRF and the second urea injection device between the SCRF and the SCR, the injection rate of the second injection device can be increased, and the ammonia storage and closing loop adjustment capability of the rear-stage SCR is used to undertake more NOx conversion tasks, so that the NOx conversion of the front-stage SCRF is reduced while ensuring that the tail gas NOx meets the standard.​ The consumption increases the number of N entering the SCRF. The amount of NOx is increased to enhance the passive regeneration efficiency of the DPF. When the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit (i.e., high efficiency in the pre-stage and low efficiency in the post-stage), the injection rate of the first injection device is increased to allow the SCRF to share more of the NOx conversion task, thus ensuring that overall NOx emissions still meet standards and avoiding excessive exhaust emissions when the post-SCR capacity is insufficient. When the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit (i.e., low efficiency in the pre-stage and high efficiency in the post-stage), the injection rate of the first injection device is reduced, while the injection rate of the second injection device is increased to avoid excessive NOx emissions. By addressing the issue of ammonia leakage caused by underutilization within the SCRF, the risk of sensor misjudgment is reduced, and the subsequent SCR handles the majority of NOx reduction, thereby improving the overall conversion efficiency and operational stability of the system. Dynamic allocation of injection tasks between the preceding and following stages achieves a balance between NOx emission compliance and DPF regeneration efficiency, while also maintaining a high NOx conversion rate and reducing the risk of ammonia leakage.

[0046] Specifically, in the low-temperature active regeneration mode, the system dynamically allocates the workload of the two injection units based on the actual conversion efficiencies of the SCRF and SCR. If the conversion efficiencies of both units are greater than or equal to the corresponding preset limits, the downstream injection unit injects more urea, allowing the subsequent SCR to handle more NOx. If the SCRF conversion efficiency is greater than or equal to the corresponding preset limit but the downstream SCR efficiency is less than the corresponding preset limit, the front-end injection rate is increased, allowing the SCRF to share more of the NOx conversion. Conversely, if the SCRF conversion efficiency is less than the corresponding preset limit but the downstream SCR efficiency is greater than or equal to the corresponding preset limit, the front-end injection rate is reduced while the rear-end injection rate is increased to prevent waste of urea injected from the front end or ammonia leakage, allowing the downstream unit to handle more NOx.

[0047] In another alternative, such as Figure 4 As shown, when the current active regeneration mode is the high-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR includes:

[0048] Step S301: When the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit, the urea injection rate of the first urea injection device is increased.

[0049] Step S302, in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device;

[0050] Step S303, in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device, and increasing the urea injection rate of the second urea injection device.

[0051] In the above embodiment, in the high-temperature active regeneration mode, the system dynamically allocates the urea injection amounts of the front and rear stages according to the differences in the actual conversion efficiencies of the SCRF and the SCR, so as to realize sufficient combustion of particulate matter and compliance of NOx emission in the high-temperature working condition. In the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, the injection rate of the first urea injection device is increased, so as to make full use of the processing capacity of the SCRF, make it undertake more NOx conversion tasks, and thus improve the urea utilization rate and the overall regeneration efficiency. In the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, the injection rate of the first urea injection device is still increased, so as to make the SCRF compensate for the deficiency of the rear SCR, and ensure that the NOx emission remains within the compliance range. In the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, the injection rate of the first urea injection device is decreased, and the injection rate of the second urea injection device is increased, so as to avoid the waste or ammonia leakage of the urea injected in the SCRF due to the low conversion efficiency, and transfer the main reduction task to the rear SCR for processing, and ensure the NOx conversion efficiency. This control logic makes the high-temperature active regeneration process improve the utilization efficiency of urea, avoid resource waste, and also take into account the particulate matter regeneration and NOx conversion, reduce the risk of ammonia leakage, and improve the safety of the whole aftertreatment system in the high-temperature regeneration.

[0052] In some example embodiments, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR includes: in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, controlling the first urea injection device and the second urea injection device to stop injection, switching the operation mode of the SCR system to a NOx low original emission mode, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0053] In the above embodiments, when it is detected that the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR are simultaneously lower than the respective conversion efficiency limit values, it is determined that the entire aftertreatment link fails or is severely degraded, and the injection of the first urea injection device and the second urea injection device is stopped to avoid the accumulation of ammonia gas that is not catalytically utilized in the exhaust gas, causing ammonia leakage, crystallization and corrosion of downstream components, while avoiding the triggering of abnormal injection by the NOx sensor due to cross-sensitivity, which misjudges ammonia gas as NOx; and the operation state is switched to a NOx low original emission mode to reduce the original NOx generation amount of the engine from the source, and in the case of aftertreatment failure, the basic compliance level of tail emissions is still maintained as much as possible and the heat management pressure is reduced; at the same time, an alarm information is output and a fault code or frozen frame data is recorded to prompt timely repair, so as to achieve the suppression of urea consumption and secondary pollution, hardware protection of the SCRF, SCR and sensor, and safety protection of the entire vehicle emission under adverse working conditions.

[0054] Specifically, the NOx low original emission mode refers to directly reducing the amount of nitrogen oxides generated by the engine by adjusting the combustion and control strategy of the engine body when the aftertreatment system such as the SCRF and the SCR cannot work normally, that is, reducing the original emission level of the engine to still try to ensure the tail emission NOx compliance when the aftertreatment fails.

[0055] In some other example embodiments, before adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, the method further includes: determining the corresponding SCRF conversion efficiency limit value according to the actual conversion efficiency of the SCRF; and determining the corresponding SCR conversion efficiency limit value according to the actual conversion efficiency of the SCR.

[0056] In the above embodiments, by determining the respective conversion efficiency limits of SCRF and SCR according to the actual conversion efficiency of SCRF calculated in real time before performing urea injection adjustment, the determination of the high and low efficiency is changed from a fixed threshold to a dynamic boundary that is self-adaptive to the working condition and aging, thereby significantly improving the accuracy and stability of subsequent control decisions. On the one hand, correct determination can still be maintained in low-temperature, sensor drift, catalyst aging, etc. conditions, ensuring that the trigger timing and duration of low-temperature or high-temperature active regeneration are more reasonable; on the other hand, the distribution of two-stage injection quantity is more in line with the real ability of the device at the moment, reducing invalid injection and urea excess, and inhibiting the risk of ammonia leakage and crystallization; in addition, the dynamic limit value can also avoid false triggering of stop injection or false alarm, and can more accurately issue NOx low original emission and alarm instructions when the efficiencies of the two stages are simultaneously lower than the dynamic limit value, thereby improving the emission compliance in all working conditions.

[0057] In some example schemes of the present application, determining the corresponding SCRF conversion efficiency limit according to the actual conversion efficiency of SCRF includes: determining the corresponding SCRF conversion efficiency limit according to a conversion efficiency mapping relationship and the actual conversion efficiency of SCRF, the conversion efficiency mapping relationship being a mapping relationship between the actual conversion efficiency of SCRF and the SCRF conversion efficiency limit; or, processing the actual conversion efficiency of SCRF by using a neural network model to obtain the SCRF conversion efficiency limit.

[0058] In the above embodiments, when a preset conversion efficiency mapping relationship is used, reasonable limits can be quickly obtained by table lookup under different temperature, flow or load conditions, ensuring that the determination result matches the current working condition; and when a neural network model is used, a dynamic limit value that is more in line with the actual operating environment can be output based on the fusion of temperature, flow, carbon load and catalyst aging state and other multi-dimensional inputs, thereby effectively covering complex and nonlinear operating conditions. Through the above manner, the setting of the SCRF conversion efficiency limit is more accurate and flexible, avoiding false positives or false negatives that may occur with a fixed threshold, and also improving the accuracy of urea injection adjustment, thereby improving the utilization rate of ammonia and the conversion efficiency of NOx in the regeneration control process.

[0059] Specifically, the integral calculation method is used to obtain the actual conversion efficiency of the SCRF in the current period of time, and combined with the exhaust gas temperature, flow rate, SCR inlet temperature, pressure difference before and after the SCRF (which can be collected by using a pressure difference sensor), carbon deposition condition, EGR rate, engine speed and torque, fuel injection amount, ambient temperature and humidity and altitude, interval time of the last regeneration, catalyst aging and sulfur poisoning degree, ammonia storage, and other operating characteristics, an input feature set is formed. In the offline stage, a large amount of historical operating data is used to calculate the "optimal efficiency limit value" under different operating conditions by comprehensively considering the NOx over-standard risk, ammonia escape risk, the influence of regeneration failure or delay, and control jitter and other factors, as the training target of the neural network model. The neural network generally uses a lightweight structure, and if necessary, time features are introduced, and reasonable constraints are added in the training process (for example, to ensure that as the temperature and flow rate increase, the limit value will not appear unreasonable sudden drop), while regularization and early stopping methods are used to avoid overfitting. After the model training is completed, the results in different temperature and flow rate intervals are calibrated to ensure the stability and reasonableness of the prediction results. The quantized and compressed neural network model is deployed in the ECU, and the real-time collected features are input into the model according to a certain time interval to obtain the dynamic conversion efficiency limit value of the SCRF. Then, the system performs engineering processing on the output: on the one hand, it is limited within the pre-labeled safe range, and avoids frequent fluctuations through filtering and threshold hysteresis technology; on the other hand, consistency and health checks are also performed (such as monitoring whether the temperature, flow rate, pressure difference or sensor state is abnormal), and once an abnormality is detected, the limit value of the pre-set mapping table is used, or the last valid value is temporarily used, and an alarm prompt is triggered. Finally, the obtained limit value is used as a reference and input into the control logic of the low-temperature or high-temperature active regeneration mode for the urea injection distribution of the SCRF inlet nozzle and the SCR inlet front nozzle, so as to realize dynamic adaptive limit value adjustment according to the operating conditions and catalyst aging condition.

[0060] In some examples of the present application, the above method further comprises: obtaining the pressure difference before and after the SCRF; and in the case that the pressure difference before and after the SCRF is greater than a pressure difference threshold value, and / or the current carbon load is less than 0, controlling the first urea injection device and the second urea injection device to stop spraying, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0061] In the above embodiments, by introducing monitoring of the pressure difference between the front and rear ends of the SCRF and the carbon load, when it is detected that the pressure difference is abnormally large, it indicates that the particulate filter is seriously blocked, or the carbon load is abnormal, for example, the carbon load is negative due to sensor failure or estimation deviation, the front and rear urea injection is immediately stopped to avoid continuing to inject urea under the condition of device failure or blockage, causing ammonia slip or catalyst damage. At the same time, an alarm information is generated to prompt the vehicle or equipment to be repaired in time. Through the above method, not only the SCRF and SCR system can be effectively protected from further damage, but also the safety and reliability of the system operation can be improved, and the risk caused by the failure of tail gas emission control can be avoided.

[0062] In order to enable those skilled in the art to more clearly understand the technical solutions of the present application, the implementation process of the control method of the SCR system of the present application will be described in detail below in combination with specific embodiments.

[0063] The present embodiment relates to a specific control method of an SCR system, which comprises the following steps as shown in Figure 5 and Figure 6

[0064] Step S1: determining whether the carbon load is greater than a limit value 1, in the case that the carbon load is greater than the limit value 1, switching to a low-temperature active regeneration mode, in the case that the carbon load is less than or equal to the limit value 1, executing step S2;

[0065] Specifically, the low-temperature active regeneration mode comprises: in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the second urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device. In the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, controlling the first urea injection device and the second urea injection device to stop working, switching the operation mode of the SCR system to a NOx low original emission mode, and generating an alarm information to prompt the SCR system to be repaired.

[0066] Step S2: determining whether the carbon load is greater than a limit value 2, in the case that the carbon load is greater than the limit value 2, switching to a high-temperature active regeneration mode, in the case that the carbon load is less than or equal to the limit value 2, exiting the flow; ​

[0067] Specifically, the high-temperature active regeneration mode includes: in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, reducing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device. In the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, controlling the first urea injection device and the second urea injection device to stop injection, switching the operating mode of the SCR system to the NOx low original emission mode, and generating an alarm information to prompt that the SCR system needs to be repaired, wherein the limit value 1 and the limit value 2 are both preset limit values, the limit value 1 is determined based on experimental data and model calculation of the SCRF and the SCR under different temperatures, flow rates and aging states, and the limit value 2 is determined by correcting the maximum allowed carbon load of the SCRF and the regeneration trigger experimental results in combination with the operating environment.

[0068] The embodiment of the present application also provides a specific implementation scenario of introducing a neural network into SCRF conversion efficiency limit value determination. In a long-term running diesel vehicle, the actual NOx conversion efficiency of the SCRF gradually decreases over time due to long-term high temperature, sulfide deposition and carbon accumulation. The traditional method uses a fixed SCRF conversion efficiency limit value for determination. Once the actual conversion efficiency of the SCRF decreases to below the fixed limit value, urea injection is stopped or an alarm is triggered. However, during the normal aging stage of the catalyst, the decrease in efficiency is within an acceptable range. If the alarm is triggered too early, the user will be forced to replace the catalyst prematurely, resulting in high maintenance costs. In the embodiment, the actual conversion efficiency of the SCRF is first obtained in real time, and a feature vector is formed by combining parameters such as the temperatures before and after the SCRF, the exhaust gas mass flow, the carbon load estimation, the engine load, the running mileage, the regeneration history and the like, and inputting the feature vector into a neural network model. The neural network model is trained using historical operation big data during an offline stage. The training data covers the efficiency decrease curves of the SCRF in different aging states. Through a cost function, the neural network model can distinguish between normal aging process and abnormal degradation conditions, and output a dynamic SCRF conversion efficiency limit value for each condition. For example, when it is detected that the actual conversion efficiency of the SCRF decreases by 10% compared with that of a new vehicle, and the decrease trend is consistent with the normal aging law of the catalyst, the neural network model will simultaneously decrease the SCRF conversion efficiency limit value by about 10%, so that the system still considers that the SCRF is in a normal working state, thereby maintaining the continuous urea injection; when the actual conversion efficiency of the SCRF decreases suddenly (such as a decrease of more than 30%), and is not consistent with the normal aging curve, the limit value output by the model will not decrease, but will be maintained at the original threshold, thereby triggering the system alarm and injection stop. Through the method, false alarms and unnecessary maintenance caused by normal aging are effectively avoided, the running cost of the vehicle throughout its life cycle is reduced, and timely alarms can be given when real faults occur.

[0069] It should be noted that the steps shown in the flowchart of the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions, and although a logical order is shown in the flowchart, in some cases, the steps shown or described herein can be executed in an order different from that shown herein.

[0070] The embodiment of the present application also provides a control device of an SCR system. It should be noted that the control device of the SCR system of the embodiment of the present application can be used to execute the control method for the SCR system provided by the embodiment of the present application. The device is used to realize the above-mentioned embodiments and preferred embodiments, and will not be described herein. 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, realization in hardware or a combination of software and hardware is also possible and contemplated.

[0071] The following introduces a control device of an SCR system provided by an embodiment of the present application.

[0072] Figure 7 is a schematic diagram of a control device of an SCR system according to an embodiment of the present application. As shown in the figure, the device comprises: Figure 7

[0073] A first acquisition unit 10 is configured to acquire a mass flow of NOx at a front end of the SCRF to obtain a first mass flow, and determine whether to acquire an actual conversion efficiency of the SCRF according to a size of the first mass flow.

[0074] Specifically, the mass flow of NOx in the exhaust gas is collected by a NOx sensor arranged at the front end of the SCRF to obtain the first mass flow; the first mass flow is integrated, and the actual conversion efficiency of the SCRF is calculated once the cumulative flow exceeds a preset limit value; if the limit value is not reached, the conversion efficiency is not calculated, and only the data is accumulated.

[0075] A second acquisition unit 20 is configured to acquire a mass flow of NOx at a front end of the SCR to obtain a second mass flow, and determine whether to acquire an actual conversion efficiency of the SCR according to a size of the second mass flow.

[0076] Specifically, the mass flow of NOx in the exhaust gas is collected by a NOx sensor arranged at the front end of the SCR to obtain the second mass flow; the second mass flow is integrated, and the actual conversion efficiency of the SCR is calculated once the cumulative flow exceeds another preset limit value; if the limit value is not reached, the original efficiency data is maintained, and the condition is waited for.

[0077] A third acquisition unit 30 is configured to acquire a current carbon load, and update a current active regeneration mode to a high-temperature active regeneration mode or a low-temperature active regeneration mode according to a size of the current carbon load.

[0078] Specifically, the current carbon load is acquired from a carbon load sensor in the DPF or the SCRF; the low-temperature active regeneration mode represents that passive regeneration is enhanced at a medium or low temperature by increasing the content of nitrogen dioxide, and is suitable for slight blockage; the high-temperature active regeneration mode represents that carbon soot is combusted by heating, and is suitable for serious blockage, but has higher energy consumption and risk.

[0079] A processing unit 40 is configured to adjust a urea injection rate of the first urea injection device and / or a urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR after the current active regeneration mode is updated.

[0080] ​Specifically, the first urea injection device is arranged at the inlet of the SCRF, i.e. in the pipeline before the engine exhaust enters the SCRF after passing through the oxidation catalyst; and the second urea injection device is arranged in the pipeline between the SCR and the SCRF, i.e. between the outlet of the SCRF and the inlet of the rear SCR.

[0081] Through the above embodiment, the NOx mass flow at the front end of the SCRF and the front end of the SCR, and the carbon load of the DPF are acquired by the first acquisition unit and the second acquisition unit, and intelligent adjustment of the working state of the urea injection device is realized. Through the third acquisition unit, the low-temperature active regeneration mode and the high-temperature active regeneration mode are automatically switched according to the level of the carbon load. The low-temperature active regeneration mode is suitable for the case where the carbon load is low, and can realize efficient regeneration under limited heat conditions; and the high-temperature active regeneration mode is aimed at the removal of stubborn deposits when the carbon load is high, and ensures the sufficiency of DPF regeneration. Through the processing unit, the injection rates of the first urea injection device installed at the front end of the SCRF and the second urea injection device installed at the rear end of the SCRF are dynamically adjusted under different regeneration modes, so as to realize fine control of NOx treatment. Under the low-temperature active regeneration mode, the required conversion efficiency of the SCRF is reduced, which can increase the N amount entering the DPF and improve the passive regeneration efficiency of the DPF; and under the high-temperature active regeneration mode, the required conversion efficiency of the SCRF is increased, which can reduce the dependence on additional heat while ensuring the NOx conversion requirement, avoid overheating of the DPF, and improve the safety of thermal management. As can be seen, the method intelligently detects the carbon load and dynamically switches the regeneration mode, and combines fine control of the urea injection rate, which not only effectively solves the thermal management problem of the SCRF system, but also significantly improves the NOx conversion efficiency of the SCRF and the SCR, can continuously maintain high conversion efficiency under complex working conditions and environmental conditions, reduces NOx emissions, meets more stringent environmental protection requirements, and solves the problem of poor conversion efficiency of the SCR system in the prior art due to the complexity of the system, which makes it difficult to perform efficient thermal management.

[0082] In an alternative, the processing unit comprises: a first adjusting module configured to increase the urea injection rate of the second urea injection device when the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value; a second adjusting module configured to increase the urea injection rate of the first urea injection device when the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value; and a third adjusting module configured to decrease the urea injection rate of the first urea injection device and increase the urea injection rate of the second urea injection device when the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value.

[0083] In the low-temperature active regeneration mode, the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR are monitored simultaneously, and the injection rates of the first urea injection device arranged at the inlet of the SCRF and the second urea injection device between the SCRF and the SCR are dynamically adjusted, so that the injection rate of the second injection device is increased, the ammonia storage and closing loop adjustment capability of the rear SCR is utilized to undertake more NOx conversion tasks, and the passive regeneration efficiency of the DPF is improved while ensuring that the tail gas NOx meets the standard. In the low-temperature active regeneration mode, the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR are monitored simultaneously, and the injection rates of the first urea injection device arranged at the inlet of the SCRF and the second urea injection device between the SCRF and the SCR are dynamically adjusted, so that the injection rate of the second injection device is increased, the ammonia storage and closing loop adjustment capability of the rear SCR is utilized to undertake more NOx conversion tasks, and the passive regeneration efficiency of the DPF is improved while ensuring that the tail gas NOx meets the standard. In the low-temperature active regeneration mode, the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR are monitored simultaneously, and the injection rates of the first urea injection device arranged at the inlet of the SCRF and the second urea injection device between the SCRF and the SCR are dynamically adjusted, so that the injection rate of the second injection device is increased, the ammonia storage and closing loop adjustment capability of the rear SCR is utilized to undertake more NOx conversion tasks, and the passive regeneration efficiency of the DPF is improved while ensuring that the tail gas NOx meets the standard. In the low-temperature active regeneration mode, the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR are monitored simultaneously, and the injection rates of the first urea injection device arranged at the inlet of the SCRF and the second urea injection device between the SCRF and the SCR are dynamically adjusted, so that the injection rate of the second injection device is increased, the ammonia storage and closing loop adjustment capability of the rear SCR is utilized to undertake more NOx conversion tasks, and the passive regeneration efficiency of the DPF is improved while ensuring that the tail gas NOx meets the standard.

[0084] Specifically, in the low-temperature active regeneration mode, the system dynamically allocates the working of the front and rear injection devices according to the actual conversion efficiencies of the SCRF and the SCR. If the conversion efficiencies of the front and rear devices are both greater than or equal to the corresponding preset limit values, the rear injection device is allowed to spray more urea, and the rear SCR is allowed to handle more NOx. If the conversion efficiency of the SCRF is greater than or equal to the corresponding preset limit value but the efficiency of the rear SCR is less than the corresponding preset limit value, the front-end injection amount is increased, and the SCRF is allowed to share more NOx conversion. If the conversion efficiency of the SCRF is less than the corresponding preset limit value but the efficiency of the rear SCR is greater than or equal to the corresponding preset limit value, the front-end injection amount is reduced, and the rear-end injection amount is increased, so as to avoid waste of urea sprayed by the front-end or ammonia leakage, and allow the rear SCR to handle more NOx.

[0085] In another alternative, the processing unit further includes: a fourth adjusting module configured to increase the urea injection rate of the first urea injection device when the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value; a fifth adjusting module configured to increase the urea injection rate of the first urea injection device when the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value; and a sixth adjusting module configured to decrease the urea injection rate of the first urea injection device and increase the urea injection rate of the second urea injection device when the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value.

[0086] In the high-temperature active regeneration mode in the above embodiments, the system dynamically allocates the urea injection amounts of the front and rear stages according to the actual conversion efficiency differences of the SCRF and the SCR, so as to realize sufficient combustion of particulate matter and NOx emission compliance under high-temperature working conditions. In the case where the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, the injection rate of the first urea injection device is increased to fully utilize the processing capacity of the SCRF and make it undertake more NOx conversion tasks, thereby improving the urea utilization rate and the overall regeneration efficiency. In the case where the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, the injection rate of the first urea injection device is still increased to make the SCRF compensate for the deficiency of the rear SCR, so as to ensure that the NOx emission remains within the compliance range. In the case where the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, the injection rate of the first urea injection device is reduced, and the injection rate of the second urea injection device is increased, so as to avoid waste or ammonia leakage of the urea injected in the SCRF due to low conversion efficiency, and to transfer the main reduction task to the rear SCR for processing, thereby ensuring the NOx conversion efficiency. This control logic enables the high-temperature active regeneration process to improve the utilization efficiency of urea, avoid resource waste, and also take into account particulate matter regeneration and NOx conversion, reduce the risk of ammonia leakage, and improve the safety of the entire aftertreatment system during high-temperature regeneration.

[0087] In some example embodiments, the processing unit further includes a control module configured to, in the case where the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, control the first urea injection device and the second urea injection device to stop injection, switch the operating mode of the SCR system to a NOx low original emission mode, and generate an alarm information to prompt that the SCR system needs to be repaired.

[0088] In the above embodiments, when the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR are both lower than the respective conversion efficiency limits, it is determined that the entire aftertreatment link fails or is severely degraded, and the injection of the first urea injection device and the second urea injection device is stopped to avoid accumulation of ammonia gas that is not catalytically utilized in the exhaust gas, causing ammonia leakage, crystallization and corrosion of downstream components, while avoiding triggering of an abnormal injection by the NOx sensor due to cross-sensitivity of ammonia gas as NOx; and the operating state is switched to a NOx low raw emission mode to reduce the original NOx generation amount of the engine from the source, and still maintain the basic compliance level of tail emissions and reduce the pressure of thermal management in the case of aftertreatment failure; at the same time, alarm information is output and fault codes or frame data are recorded to prompt timely maintenance, so as to achieve suppression of urea consumption and secondary pollution, hardware protection of the SCRF, SCR and sensor, and safety protection of the entire vehicle emission under adverse working conditions.

[0089] Specifically, the NOx low raw emission mode refers to directly reducing the amount of nitrogen oxides generated by the engine by adjusting the combustion and control strategy of the engine body when the aftertreatment system such as the SCRF and the SCR cannot work normally, that is, reducing the original emission level of the engine, so as to still try to ensure the tail emission NOx compliance when the aftertreatment fails.

[0090] In some other exemplary embodiments, the device further comprises a first determination unit configured to determine the corresponding SCRF conversion efficiency limit according to the actual conversion efficiency of the SCRF, and a second determination unit configured to determine the corresponding SCR conversion efficiency limit according to the actual conversion efficiency of the SCR.

[0091] In the above embodiments, by determining the respective conversion efficiency limits according to the actual conversion efficiencies of the SCRF and the SCR calculated in real time before performing urea injection adjustment, the high and low efficiencies are determined by dynamic boundaries that are self-adaptive to the working conditions and aging, instead of fixed thresholds, thereby significantly improving the accuracy and stability of subsequent control decisions. On the one hand, correct determination can still be maintained under conditions such as low temperature, sensor drift and catalyst aging, ensuring that the trigger timing and duration of low-temperature or high-temperature active regeneration are more reasonable; on the other hand, the distribution of two-stage injection amounts is more in line with the real ability of the device at the moment, reducing invalid injection and urea excess, and inhibiting the risk of ammonia leakage and crystallization; in addition, the dynamic limit value can also avoid false triggering of injection stop or false alarm, and can more accurately issue NOx low raw emission and alarm instructions when the efficiencies of the two stages are both lower than the dynamic limit value, thereby improving the emission compliance under all working conditions.

[0092] In some example schemes of the present application, the first determining unit comprises a determining module configured to determine the corresponding SCRF conversion efficiency limit value according to the conversion efficiency mapping relationship and the actual conversion efficiency of the SCRF, wherein the conversion efficiency mapping relationship is a mapping relationship between the actual conversion efficiency of the SCRF and the SCRF conversion efficiency limit value; and a processing module configured to process the actual conversion efficiency of the SCRF by using a neural network model to obtain the SCRF conversion efficiency limit value.

[0093] In the above embodiments, when the preset conversion efficiency mapping relationship is used, reasonable limit values can be quickly obtained by table lookup under different temperature, flow or load conditions, so as to ensure that the determination result matches the current working condition; and when the neural network model is used, dynamic limit values that are more in line with the actual operating environment can be output on the basis of fusing multi-dimensional inputs such as temperature, flow, carbon load and catalyst aging state, so as to effectively cover complex and nonlinear operating conditions. In this way, the setting of the SCRF conversion efficiency limit value is more accurate and flexible, which avoids possible misjudgment or missed judgment under a fixed threshold, and also improves the accuracy of urea injection regulation and the utilization rate of ammonia and the conversion efficiency of NOx in the regeneration control process.

[0094] Specifically, the integral calculation method is used to obtain the actual conversion efficiency of the SCRF in the current period of time, and combined with the exhaust gas temperature, flow, SCR inlet temperature, pressure difference before and after the SCRF, carbon deposition, EGR rate, engine speed and torque, fuel injection amount, ambient temperature and humidity and altitude, interval time of the last regeneration, catalyst aging and sulfur poisoning degree, ammonia storage, and other operating characteristics, an input feature set is formed. In the offline stage, a large amount of historical operating data is used to calculate the "optimal efficiency limit value" under different operating conditions by comprehensively considering the risk of NOx exceeding the standard, the risk of ammonia escape, the influence of regeneration failure or delay, and other factors such as control jitter, as the training target of the neural network model. The neural network generally uses a lightweight structure, and if necessary, time features are introduced, and reasonable constraints are added during the training process (for example, to ensure that as the temperature and flow increase, the limit value will not appear unreasonable drop), while using regularization and early stopping methods to avoid overfitting. After the model training is completed, the results in different temperature and flow intervals will be calibrated to ensure the stability and reasonableness of the prediction results. The quantized and compressed neural network model will be deployed in the ECU, and the real-time collected features will be input into the model according to a certain time interval to obtain the dynamic conversion efficiency limit value of the SCRF. Then, the system will perform engineering processing on the output: on the one hand, it will be limited within the pre-labeled safe range, and through filtering and threshold hysteresis technology, it will avoid frequent fluctuations; on the other hand, it will also perform consistency and health checks (such as monitoring whether the temperature, flow, pressure difference, or sensor state is abnormal), and once an abnormality is detected, it will fall back to the limit value of the pre-set mapping table, or temporarily use the last valid value, and trigger an alarm prompt. Finally, the obtained limit value will be used as a reference and input into the control logic of the low-temperature or high-temperature active regeneration mode for the urea injection distribution of the SCRF inlet nozzle and the SCR inlet front nozzle, so as to realize dynamic adaptive limit value adjustment according to the operating conditions and catalyst aging conditions.

[0095] In some examples of the present application, the device further comprises a fourth acquisition unit for acquiring the pressure difference before and after the SCRF; in the case that the pressure difference before and after the SCRF is greater than the pressure difference threshold, and / or the current carbon load is less than 0, the first urea injection device and the second urea injection device are controlled to stop injection, and an alarm information is generated to prompt that the SCR system needs to be repaired.

[0096] In the above embodiment, by introducing the monitoring of the pressure difference between the front and rear ends of the SCRF and the carbon load, when it is detected that the pressure difference is abnormally large, it indicates that the particulate filter is seriously blocked, or the carbon load is abnormal, for example, the sensor fails or the estimated deviation causes the carbon load to be negative, the front and rear urea injection is immediately stopped to avoid continuing to inject urea under the condition of device failure or blockage, causing ammonia slip or catalyst damage. At the same time, an alarm information is generated to prompt the vehicle or equipment to be repaired in time. Through the above method, not only the SCRF and the SCR system can be effectively protected from further damage, but also the safety and reliability of the system operation can be improved, and the risk caused by the failure of the exhaust emission control can be avoided.

[0097] The control device of the above SCR system includes a processor and a memory, and the first acquisition unit, the first acquisition unit, the first acquisition unit, and the processing unit are all stored in the memory as program units. The corresponding functions are realized by the processor executing the above program units stored in the memory. The above modules are all located in the same processor; or, the above modules are respectively located in different processors in any combination.

[0098] The processor includes a core, and the core retrieves the corresponding program unit from the memory. The core can be one or more, and the core parameters are adjusted to at least solve the problem that the SCR system in the prior art is difficult to perform efficient thermal management due to the complexity of the system, thereby causing poor conversion efficiency of the SCR system.

[0099] The memory can include a non-persistent memory in a computer readable medium, a random access memory (RAM), and / or a non-volatile memory such as a read-only memory (ROM) or a flash memory (flash RAM), and the memory includes at least one memory chip.

[0100] The embodiment of the present application provides a computer readable storage medium, and the computer readable storage medium includes a stored program, wherein when the program runs, the device where the computer readable storage medium is located performs the control method of the SCR system.

[0101] Specifically, the control method of the SCR system includes:

[0102] In step S101, the mass flow of the front-end NOx of the SCRF is acquired to obtain a first mass flow, and whether the actual conversion efficiency of the SCRF is acquired is determined according to the size of the first mass flow.

[0103] Specifically, the mass flow of NOx in the exhaust gas is collected by the NOx sensor arranged at the front end of the SCRF to obtain a first mass flow; the first mass flow is integrated, and when the cumulative flow exceeds a preset limit, the actual conversion efficiency of the SCRF is calculated once; if the limit is not reached, the conversion efficiency is not calculated, and only the data is accumulated.

[0104] In step S102, the mass flow of NOx at the front end of the SCR is obtained to obtain a second mass flow, and whether the actual conversion efficiency of the SCR is obtained is determined according to the size of the second mass flow.

[0105] Specifically, the mass flow of NOx in the exhaust gas is collected by the NOx sensor arranged at the front end of the SCRF to obtain a first mass flow; the first mass flow is integrated, and when the cumulative flow exceeds a preset limit, the actual conversion efficiency of the SCRF is calculated once; if the limit is not reached, the conversion efficiency is not calculated, and only the data is accumulated.

[0106] In step S103, the current carbon load is obtained, and the current active regeneration mode is updated to a high-temperature active regeneration mode or a low-temperature active regeneration mode according to the size of the current carbon load.

[0107] Specifically, the current carbon load is obtained from the carbon load sensor in the DPF or the SCRF; wherein the low-temperature active regeneration mode represents that the passive regeneration is enhanced at medium and low temperatures by increasing the nitrogen dioxide content, which is suitable for slight blockage; the high-temperature active regeneration mode represents that the soot is combusted by heating, which is suitable for serious blockage, but has higher energy consumption and risk.

[0108] In step S104, after updating the current active regeneration mode, the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device is adjusted according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR.

[0109] Specifically, the first urea injection device is arranged at the inlet of the SCRF, i.e. in the pipeline before the engine exhaust enters the SCRF after passing through the oxidation catalyst; the second urea injection device is arranged in the pipeline between the SCR and the SCRF, i.e. between the outlet of the SCRF and the inlet of the rear SCR.

[0110] In an embodiment of the application, in the case that the current active regeneration mode is the low-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the second urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0111] In an embodiment of the application, in the case that the current active regeneration mode is the high-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0112] In an embodiment of the present application, the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device is adjusted according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, including: in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, controlling the first urea injection device and the second urea injection device to stop injection work, switching the operation mode of the SCR system to a NOx low original emission mode, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0113] In an embodiment of the present application, before the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device is adjusted according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, the method further includes: determining the corresponding SCRF conversion efficiency limit value according to the actual conversion efficiency of the SCRF; and determining the corresponding SCR conversion efficiency limit value according to the actual conversion efficiency of the SCR.

[0114] In an embodiment of the present application, the corresponding SCRF conversion efficiency limit value is determined according to the actual conversion efficiency of the SCRF, including: determining the corresponding SCRF conversion efficiency limit value according to a conversion efficiency mapping relationship and the actual conversion efficiency of the SCRF, the conversion efficiency mapping relationship being a mapping relationship between the actual conversion efficiency of the SCRF and the SCRF conversion efficiency limit value; or using a neural network model to process the actual conversion efficiency of the SCRF to obtain the SCRF conversion efficiency limit value.

[0115] In an embodiment of the present application, the method further includes: obtaining the front-rear end pressure difference of the SCRF; in the case that the front-rear end pressure difference of the SCRF is greater than a pressure difference threshold value and / or the current carbon load is less than 0, controlling the first urea injection device and the second urea injection device to stop injection work, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0116] An embodiment of the present application provides a SCR system, including: Figure 2The system shown, comprising: SCRF 100, SCR 200, first urea injection device 300, second urea injection device 400 and controller, the first urea injection device 300 is installed to the front end of the SCRF 100, the second urea injection device 400 is installed to the rear end of the SCRF 100, the rear end of the SCRF 100 is communicated with the front end of the SCR 200, the SCRF 100 is an SCR with a DPF coated with an SCR catalyst, the controller communicates with the first urea injection device and the second urea injection device respectively, and the controller is used to execute any one of the above methods 1 to 7. The system executes the program to realize at least the following steps:

[0117] Step S101, obtaining the mass flow of NOx at the front end of the SCRF 100 to obtain a first mass flow, and determining whether to obtain the actual conversion efficiency of the SCRF 100 according to the size of the first mass flow;

[0118] Specifically, the mass flow of NOx in the exhaust gas is collected by the NOx sensor arranged at the front end of the SCRF to obtain a first mass flow; the first mass flow is integrated, and when the cumulative flow exceeds a preset limit value, the actual conversion efficiency of the SCRF is calculated once; if the limit value is not reached, the conversion efficiency is not calculated, and only the data is accumulated.

[0119] Step S102, obtaining the mass flow of NOx at the front end of the SCR 200 to obtain a second mass flow, and determining whether to obtain the actual conversion efficiency of the SCR 200 according to the size of the second mass flow;

[0120] Specifically, the mass flow of NOx in the exhaust gas is collected by the NOx sensor arranged at the front end of the SCR 200 to obtain a second mass flow; the second mass flow is integrated, and when the cumulative flow exceeds another preset limit value, the actual conversion efficiency of the SCR 200 is calculated once; if the limit value is not reached, the original efficiency data is maintained and the condition is waited for.

[0121] Step S103, obtaining the current carbon load, and updating the current active regeneration mode to a high-temperature active regeneration mode or a low-temperature active regeneration mode according to the size of the current carbon load;

[0122] Specifically, the current carbon load is obtained from the carbon load sensor in the DPF or the SCRF; wherein the low-temperature active regeneration mode represents enhancing passive regeneration at medium and low temperatures by increasing the content of nitrogen dioxide, which is suitable for mild blockage; the high-temperature active regeneration mode represents burning soot by heating, which is suitable for severe blockage but has higher energy consumption and risk.

[0123] Step S104, after updating the current active regeneration mode, adjusting the urea injection rate of the first urea injection device 300 and / or the urea injection rate of the second urea injection device 400 according to the actual conversion efficiency of the SCRF 100 and the actual conversion efficiency of the SCR 200.

[0124] Specifically, the first urea injection device is arranged at the inlet of the SCRF, i.e. in the pipeline before the engine exhaust gas enters the SCRF after passing through the oxidation catalyst; the second urea injection device is arranged in the pipeline between the SCR and the SCRF, i.e. between the outlet of the SCRF and the inlet of the rear SCR.

[0125] In an embodiment of the present application, when the current active regeneration mode is the low-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR includes: when the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the second urea injection device; when the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; when the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0126] In an embodiment of the present application, in the case that the current active regeneration mode is the high-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, increasing the urea injection rate of the first urea injection device; in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit value, decreasing the urea injection rate of the first urea injection device and increasing the urea injection rate of the second urea injection device.

[0127] In an embodiment of the present application, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR comprises: in the case that the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit value and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit value, controlling the first urea injection device and the second urea injection device to stop injection, switching the operation mode of the SCR system to the NOx low original emission mode, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0128] In an embodiment of the present application, before adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, the method further comprises: determining the corresponding SCRF conversion efficiency limit value according to the actual conversion efficiency of the SCRF; determining the corresponding SCR conversion efficiency limit value according to the actual conversion efficiency of the SCR.

[0129] In an embodiment of the present application, the corresponding SCRF conversion efficiency limit value is determined according to the actual conversion efficiency of the SCRF, including: determining the corresponding SCRF conversion efficiency limit value according to the actual conversion efficiency of the SCRF and a conversion efficiency mapping relationship, the conversion efficiency mapping relationship being a mapping relationship between the actual conversion efficiency of the SCRF and the SCRF conversion efficiency limit value; or, using a neural network model to process the actual conversion efficiency of the SCRF to obtain the SCRF conversion efficiency limit value.

[0130] In an embodiment of the present application, the method further includes: obtaining the front-rear end pressure difference of the SCRF; in the case that the front-rear end pressure difference of the SCRF is greater than a pressure difference threshold, and / or the current carbon load is less than 0, controlling the first urea injection device and the second urea injection device to stop injection work, and generating an alarm information to prompt that the SCR system needs to be repaired.

[0131] Exemplarily, the SCRF system arrangement diagram is as shown in Figure 2 The main components include an oxidation catalytic converter 500, an SCRF 100, an SCR 200, an ammonia escape trap 600 (i.e., ASC), a first temperature sensor 700 and a first nitrogen oxide sensor 800 in front of the oxidation catalytic converter 500, a first urea injection device 300 and a second temperature sensor 710 in front of the SCRF 100, a second urea injection device 400, a third temperature sensor 720 and a second nitrogen oxide sensor 810 between the SCRF 100 and the SCR 200, and a third nitrogen oxide sensor 820 after the ammonia escape trap 600, and a pressure difference sensor 900 on the SCRF 100.

[0132] The device herein can be a server, a PC, a PAD, a mobile phone, etc.

[0133] Obviously, those skilled in the art should understand that the modules or steps of the present application described above can be realized by general computing devices, which can be concentrated on a single computing device or distributed on a network composed of multiple computing devices, and can be realized by program codes executable by the computing devices, so that they can be stored in storage devices and executed by the computing devices, and in some cases, the steps shown or described herein can be executed in different orders, or they can be manufactured into individual integrated circuit modules, or multiple modules or steps can be manufactured into a single integrated circuit module. Therefore, the present application is not limited to any specific combination of hardware and software.

[0134] Those skilled in the art will appreciate that embodiments of the present application can be readily used as software, hardware, or a combination of software and hardware. In a typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0135] 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 functions specified in the flowchart block or blocks. Figure 1 means for performing each of the functions specified in the flowchart block or blocks.

[0136] 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 functions specified in the flowchart block or blocks. Figure 1 means for performing each of the functions specified in the flowchart block or blocks.

[0137] 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 functions specified in the flowchart block or blocks. Figure 1 means for performing each of the functions specified in the flowchart block or blocks.

[0138] In one typical configuration, a computing device includes one or more processors (CPUs), input / output interfaces, network interfaces, and memory.

[0139] 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 a read only memory (ROM) device, a floppy disk, a flexible disk, hard disk, or a tape, cloud storage, flash memory card, or another suitable data storage device. The memory stores a data processing application, in accordance with an embodiment of the present application.

[0140] 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 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.

[0141] The technical features of the above-described embodiments can be combined in any manner. In order to make the description concise, not all possible combinations of the technical features in the above-described embodiments are described, but as long as the combinations of the technical features do not exist contradictions, it should be considered as the scope of the present disclosure.

[0142] 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.

[0143] From the above description, it can be seen that the above-described embodiments of the present application achieve the following technical effects:

[0144] 1) The control method of the SCR system of the present application realizes intelligent adjustment of the working state of the urea injection device by monitoring the NOx mass flow at the front end of the SCRF and the front end of the SCR, and the carbon load of the DPF. According to the high and low of the carbon load, the low-temperature active regeneration mode and the high-temperature active regeneration mode are automatically switched. The low-temperature active regeneration mode is suitable for the case of low carbon load, and can realize efficient regeneration under limited heat conditions; while the high-temperature active regeneration mode is aimed at the removal of stubborn deposits when the carbon load is high, to ensure the sufficiency of DPF regeneration. Under different regeneration modes, the injection rates of the first urea injection device installed at the front end of the SCRF and the second urea injection device installed at the rear end of the SCRF are dynamically adjusted, so as to realize fine control of NOx treatment. Under the low-temperature active regeneration mode, by reducing the demand conversion efficiency of the SCRF, the N amount entering the DPF can be increased, and the passive regeneration efficiency of the DPF is improved; while under the high-temperature active regeneration mode, by increasing the demand conversion efficiency of the SCRF, the dependence on additional heat is reduced while ensuring the NOx conversion demand, avoiding overheating of the DPF, and improving the safety of thermal management. As can be seen, by intelligent detection of the carbon load and dynamic switching of the regeneration mode, combined with fine control of the urea injection rate, not only the thermal management problem of the SCRF system is effectively solved, but also the NOx conversion efficiency of the SCRF and the SCR is significantly improved, which can continuously maintain high conversion efficiency under complex working conditions and environmental conditions, reduce NOx emissions, meet more stringent environmental protection requirements, and solve the problem of poor conversion efficiency of the SCR system in the prior art due to the complexity of the system, which makes it difficult to carry out efficient thermal management.

[0145] 2) The control device of the SCR system of the present application realizes intelligent adjustment of the working state of the urea injection device by obtaining the NOx mass flow at the front end of the SCRF and the front end of the SCR, and the carbon load of the DPF through the first acquisition unit and the second acquisition unit. Through the third acquisition unit, the low-temperature active regeneration mode and the high-temperature active regeneration mode are automatically switched according to the high and low of the carbon load. The low-temperature active regeneration mode is suitable for the case of low carbon load, and can realize efficient regeneration under limited heat conditions; while the high-temperature active regeneration mode is aimed at the removal of stubborn deposits when the carbon load is high, to ensure the sufficiency of DPF regeneration. Through the processing unit, under different regeneration modes, the injection rates of the first urea injection device installed at the front end of the SCRF and the second urea injection device installed at the rear end of the SCRF are dynamically adjusted, so as to realize fine control of NOx treatment. Under the low-temperature active regeneration mode, by reducing the demand conversion efficiency of the SCRF, the N In the low-temperature passive regeneration mode, the carbon load of the SCRF is detected, and the urea injection rate is controlled according to the carbon load, so that the passive regeneration efficiency of the DPF is improved; and in the high-temperature active regeneration mode, the demand conversion efficiency of the SCRF is improved, so that the NOx conversion demand is ensured while the dependence on additional heat is reduced, the DPF overheating is avoided, and the safety of thermal management is improved. As can be seen, by means of intelligent detection of the carbon load and dynamic switching of the regeneration mode, combined with fine control of the urea injection rate, the method not only effectively solves the problem of thermal management of the SCRF system, but also significantly improves the NOx conversion efficiency of the SCRF and the SCR, can continuously maintain a high conversion efficiency under complex working conditions and environmental conditions, reduces NOx emissions, meets more stringent environmental protection requirements, and solves the problem that the conversion efficiency of the SCR system is poor due to the complexity of the system in the prior art, which makes it difficult to perform efficient thermal management.

[0146] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. Those skilled in the art can make various modifications and changes to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A control method for an SCR system, applied to a controller in an SCR system, the SCR system further comprising an SCRF (100), an SCR (200), a first urea injection device (300), and a second urea injection device (400), wherein the first urea injection device (300) is installed at the front end of the SCRF (100), the second urea injection device (400) is installed at the rear end of the SCRF (100), the rear end of the SCRF (100) is connected to the front end of the SCR (200), and the SCRF (100) is an SCR (200) with an SCR catalyst coated on a DPF, characterized in that, include: Obtain the mass flow rate of the front-end NOx of the SCRF (100) to obtain the first mass flow rate, and determine whether to obtain the actual conversion efficiency of the SCRF (100) based on the magnitude of the first mass flow rate; Obtain the mass flow rate of NOx at the front end of the SCR (200), obtain the second mass flow rate, and determine whether to obtain the actual conversion efficiency of the SCR (200) based on the magnitude of the second mass flow rate. Obtain the current carbon loading and update the current active regeneration mode to either high-temperature active regeneration mode or low-temperature active regeneration mode based on the current carbon loading. After updating the current active regeneration mode, the urea injection rate of the first urea injection device (300) and / or the urea injection rate of the second urea injection device (400) are adjusted according to the actual conversion efficiency of the SCRF (100) and the actual conversion efficiency of the SCR (200).

2. The method according to claim 1, characterized in that, When the current active regeneration mode is the low-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR includes: When the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit, the urea injection rate of the second urea injection device is increased. When the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit, the urea injection rate of the first urea injection device is increased. If the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit, the urea injection rate of the first urea injection device is reduced, and the urea injection rate of the second urea injection device is increased.

3. The method according to claim 1, characterized in that, When the current active regeneration mode is the high-temperature active regeneration mode, adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device according to the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR includes: When the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit, the urea injection rate of the first urea injection device is increased. When the actual conversion efficiency of the SCRF is greater than or equal to the SCRF conversion efficiency limit and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit, the urea injection rate of the first urea injection device is increased. If the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit, and the actual conversion efficiency of the SCR is greater than or equal to the SCR conversion efficiency limit, the urea injection rate of the first urea injection device is reduced, and the urea injection rate of the second urea injection device is increased.

4. The method according to claim 1, characterized in that, Adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device based on the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR includes: If the actual conversion efficiency of the SCRF is less than the SCRF conversion efficiency limit, and the actual conversion efficiency of the SCR is less than the SCR conversion efficiency limit, the first urea injection device and the second urea injection device are controlled to stop injection, the operating mode of the SCR system is switched to the NOx low emission mode, and an alarm message is generated to indicate that the SCR system needs maintenance.

5. The method according to claim 1, characterized in that, Before adjusting the urea injection rate of the first urea injection device and / or the urea injection rate of the second urea injection device based on the actual conversion efficiency of the SCRF and the actual conversion efficiency of the SCR, the method further includes: The corresponding SCRF conversion efficiency limit is determined based on the actual conversion efficiency of the SCRF. The corresponding SCR conversion efficiency limit is determined based on the actual conversion efficiency of the SCR.

6. The method according to claim 5, characterized in that, Determine the corresponding SCRF conversion efficiency limit based on the actual conversion efficiency of the SCRF, including: The corresponding SCRF conversion efficiency limit is determined based on the conversion efficiency mapping relationship and the actual conversion efficiency of the SCRF. The conversion efficiency mapping relationship is the mapping relationship between the actual conversion efficiency of the SCRF and the SCRF conversion efficiency limit. Alternatively, a neural network model can be used to process the actual conversion efficiency of the SCRF to obtain the conversion efficiency limit of the SCRF.

7. The method according to any one of claims 1 to 6, characterized in that, The method further includes: Obtain the pressure difference between the front and rear ends of the SCRF; If the pressure difference between the front and rear ends of the SCRF is greater than the pressure difference threshold, and / or the current carbon loading is less than 0, the first urea injection device and the second urea injection device are controlled to stop injection and an alarm message is generated to indicate that the SCR system needs maintenance.

8. A control device for an SCR system, the SCR system further comprising an SCRF (100), an SCR (200), a first urea injection device (300), and a second urea injection device (400), wherein the first urea injection device (300) is installed at the front end of the SCRF (100), the second urea injection device (400) is installed at the rear end of the SCRF (100), the rear end of the SCRF (100) is connected to the front end of the SCR (200), and the SCRF (100) is an SCR (200) with an SCR catalyst coated on a DPF, characterized in that, include: The first acquisition unit is used to acquire the mass flow rate of the front-end NOx of the SCRF (100), obtain the first mass flow rate, and determine whether to acquire the actual conversion efficiency of the SCRF (100) based on the magnitude of the first mass flow rate. The second acquisition unit is used to acquire the mass flow rate of NOx at the front end of the SCR (200), obtain the second mass flow rate, and determine whether to acquire the actual conversion efficiency of the SCR (200) based on the magnitude of the second mass flow rate. The third acquisition unit is used to acquire the current carbon loading and update the current active regeneration mode to either high-temperature active regeneration mode or low-temperature active regeneration mode based on the current carbon loading. The processing unit is configured to, after updating the current active regeneration mode, adjust the urea injection rate of the first urea injection device (300) and / or the urea injection rate of the second urea injection device (400) according to the actual conversion efficiency of the SCRF (100) and the actual conversion efficiency of the SCR (200).

9. A computer-readable storage medium, characterized in that, The computer-readable storage medium includes a stored program, wherein, when the program is executed, it controls the device on which the computer-readable storage medium is located to perform the method according to any one of claims 1 to 7.

10. An SCR system, characterized in that, include: The method comprises an SCRF (100), an SCR (200), a first urea injection device (300), a second urea injection device (400), and a controller. The first urea injection device (300) is installed at the front end of the SCRF (100), and the second urea injection device (400) is installed at the rear end of the SCRF (100). The rear end of the SCRF (100) is connected to the front end of the SCR (200). The SCRF (100) is an SCR (200) with an SCR catalyst coated on a DPF. The controller communicates with the first urea injection device (300) and the second urea injection device (400) respectively. The controller is used to perform the method according to any one of claims 1 to 7.

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