Fault detection method for urea injection system, storage medium and electronic device

Abstract

This application provides a fault detection method, storage medium, and electronic device for a urea injection system. The method includes: controlling the dual-SCR urea system to enter a testing phase when the system meets test conditions; after the system enters the testing phase, controlling the first and second urea nozzles to stop injection, then using a preset control algorithm to maintain the urea pump pressure at a preset pressure; using a constant value control algorithm to control the urea pump and acquiring a first pump pressure drop within a first preset time period; if the first pump pressure drop is less than a preset pressure drop value, determining that the dual-SCR urea system has no leakage fault. Anomaly detection of the dual-injection urea system is achieved based on the urea pump pressure.

Description

Technical Field

[0001] This application relates to the field of urea injection, and more specifically, to a fault detection method, storage medium, and electronic device for a urea injection system. Background Technology

[0002] SCR urea injection systems are used to treat nitrogen oxides in engine exhaust, thereby reducing the amount of nitrogen oxides emitted into the atmosphere. With increasingly stringent emission regulations, dual-injection urea systems are being adopted as one of the aftertreatment routes. Detecting abnormalities such as pipeline tightness, injection consistency between the two nozzles, and nozzle aging and clogging is crucial; however, there is a lack of precise solutions for detecting abnormalities in dual-injection urea injection systems. Summary of the Invention

[0003] The main objective of this application is to provide a fault detection method, storage medium, and electronic device for a urea injection system, so as to at least solve the problem of the lack of a solution for accurately detecting abnormal faults in a dual-injection urea injection system in the related art.

[0004] To achieve the above objectives, according to one aspect of this application, a fault detection method for a urea injection system is provided. The urea injection system is a dual-SCR urea system, comprising a first SCR mixer and a second SCR mixer arranged in series. The first SCR mixer includes a first urea nozzle, and the second SCR mixer includes a second urea nozzle. The dual-SCR urea system further includes a urea pump communicating with the first and second urea nozzles. The method includes: when the dual-SCR urea system meets test conditions, controlling the dual-SCR urea system to enter a test phase, wherein the test conditions... The condition includes at least one of the following: the dual-SCR urea system has no urea supply failure; the cumulative urea injection volume of the dual-SCR urea system after entering the injection stage is greater than the injection volume threshold; and no fault test has been performed during this driving cycle. After the dual-SCR urea system enters the test stage, after controlling the first urea nozzle and the second urea nozzle to stop injection, the pump pressure of the urea pump is maintained at the preset pump pressure using a preset control algorithm. Then, the urea pump is controlled using a constant value control algorithm, and the first pump pressure drop within a first preset time period is obtained. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual-SCR urea system has no leakage failure.

[0005] Optionally, after controlling the urea pump using a constant value control algorithm and obtaining the first pump pressure drop within a first preset time period, the method further includes: if the first pump pressure drop is greater than or equal to the preset pressure drop value, using the preset control algorithm to control the pump pressure of the urea pump to rise to the sum of the preset pump pressure and the preset pressure drop value, then using the constant value control algorithm to control the urea pump and obtaining the second pump pressure drop within a second preset time period; if the second pump pressure drop is less than the preset pressure drop value, determining that the dual-SCR urea system has no leakage fault; if the second pump pressure drop is greater than or equal to the preset pressure drop value, determining that the dual-SCR urea system has a leakage fault.

[0006] Optionally, the method further includes: after the dual-SCR urea system has no leakage fault and the pump pressure of the urea pump is maintained at the preset pump pressure, controlling the dual-SCR urea system to enter a first sub-test stage, wherein, in the first sub-test stage, the first urea nozzle stops spraying after spraying at a preset duty cycle for a third preset time period, and the second urea nozzle does not spray; obtaining a third pump pressure drop in the first sub-test stage, the third pump pressure drop being the pressure drop of the pump pressure at the moment the first urea nozzle stops spraying relative to the preset pump pressure; in the first sub-test stage After the first test phase ends, the pump pressure of the urea pump is increased to the preset pump pressure, and then the dual-SCR urea system is controlled to enter the second sub-test phase. In the second sub-test phase, the second urea nozzle sprays at the preset duty cycle for a third preset time period and then stops spraying, while the first urea nozzle does not spray. The fourth pump pressure drop in the second sub-test phase is obtained. The fourth pump pressure drop is the pump pressure at the moment when the second urea nozzle stops spraying relative to the preset pump pressure. Based on the ratio of the third pump pressure drop to the fourth pump pressure drop, it is determined whether there is a nozzle blockage fault.

[0007] Optionally, determining whether a nozzle blockage fault exists based on the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump includes: obtaining the difference between a first ratio and a second ratio, wherein the first ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the current driving cycle, and the second ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the previous driving cycle; if the difference between the first ratio and the second ratio is less than a difference threshold, it is determined that the nozzle blockage fault does not exist.

[0008] Optionally, the method further includes: if the difference between the first ratio and the second ratio is greater than or equal to the difference threshold, updating the average of the first ratio and the second ratio to the ratio of the third pump pressure drop and the fourth pump pressure drop measured in the previous driving cycle.

[0009] Optionally, the method further includes: when the difference between the first ratio and the second ratio is greater than or equal to the difference threshold, performing a first acquisition step: controlling the dual SCR urea system to enter the first sub-test stage and the second sub-test stage again to acquire the third pump pressure drop and the fourth pump pressure drop again; a second acquisition step: acquiring the average value of all ratios of the third pump pressure drop and the fourth pump pressure drop within the current driving cycle; when the absolute value of the difference between the currently acquired ratio of the third pump pressure drop and the fourth pump pressure drop and the average value is less than the difference threshold, determining that the first urea nozzle and the second urea nozzle have no injection error at the current moment.

[0010] Optionally, the method further includes: if the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is greater than or equal to the difference threshold, repeating the first acquisition step and the second acquisition step at least once in sequence until at least one of the following is satisfied: the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is less than the difference threshold, or the number of tests reaches the upper limit value.

[0011] Optionally, the method further includes: according to the formula Determine the mass flow rate ratio for this driving cycle, where r std The mass flow rate ratio is represented by N, which represents the total number of tests performed in this driving cycle. Each test includes the first sub-test phase and the second sub-test phase. r i This represents the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump obtained in the i-th test. This represents the average of the ratios of the pressure drops of the third pump and the fourth pump obtained in this driving cycle.

[0012] According to another aspect of this application, a computer-readable storage medium is provided, the computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform any of the fault detection methods of the urea injection system described above.

[0013] According to another aspect of this application, an electronic device is provided, comprising: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including methods for performing any of the fault detection methods for the urea injection system described above.

[0014] By applying the technical solution of this application, when the dual-SCR urea system meets the test conditions, the system is controlled to enter the test phase. After entering the test phase, the first and second urea nozzles are stopped from spraying. A preset control algorithm is used to maintain the urea pump pressure at a preset pressure. A constant value control algorithm is then used to control the urea pump and obtain the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than a preset value, it is determined that the dual-SCR urea system has no leakage fault. The system enters the test phase when the test conditions are met. During the test phase, the impact on the urea pump pressure is reduced by closing the first and second urea nozzles. Then, the change in the urea pump pressure is observed to determine whether a leakage fault exists in the dual-SCR urea system. This achieves accurate determination of a leak-free fault. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of this application. The illustrative embodiments and descriptions of this application are used to explain this application and do not constitute an undue limitation of this application. In the drawings:

[0016] Figure 1 A hardware structure block diagram of a mobile terminal for performing a fault detection method for a urea injection system according to an embodiment of this application is shown.

[0017] Figure 2 A schematic diagram of a dual-SCR urea system according to an embodiment of this application is shown;

[0018] Figure 3 A schematic flowchart of a fault detection method for a urea injection system according to an embodiment of this application is shown.

[0019] Figure 4 A schematic diagram of a pressure test principle according to an embodiment of this application is shown;

[0020] Figure 5 A flowchart illustrating a method for determining the presence or absence of injection error according to an embodiment of this application is shown;

[0021] Figure 6 A structural block diagram of a fault detection device for a urea injection system provided according to an embodiment of this application is shown.

[0022] The above figures include the following reference numerals:

[0023] 10. First urea nozzle; 20. First SCR; 30. Second urea nozzle; 40. Second SCR; 50. Urea pump. Detailed Implementation

[0024] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments.

[0025] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0026] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0027] For ease of description, the following explains some of the nouns or terms used in the embodiments of this application:

[0028] SCR: Selectively Catalytic Reduction, currently commonly used to reduce the concentration of nitrogen oxides in exhaust emissions by injecting urea before the SCR.

[0029] Urea Pump: The urea pump is used in the urea solution metering and injection unit of the SCR (Selective Catalytic Reduction) system for diesel engine exhaust aftertreatment. It provides the necessary injection pressure and flow rate for the SCR system. The urea pump itself does not have urea injection quantity metering functionality; the system uses a dedicated electronically controlled urea nozzle for metering injection. The ECU directly acquires signals from the pump's internal pressure sensor and communicates with the pump's internal controller via PWM to control the pump's motor. The pressure stability of the urea pump is controlled by the ECU through an algorithm.

[0030] As described in the background section, there is a lack of a solution for accurately detecting abnormal faults in dual-injection urea injection systems in the related technologies. In order to solve the problem of the lack of a solution for accurately detecting abnormal faults in dual-injection urea injection systems in the related technologies, embodiments of this application provide a fault detection method, storage medium, and electronic device for urea injection systems.

[0031] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0032] The methods and embodiments provided in this application can be executed on a mobile terminal, computer terminal, or similar computing device. Taking running on a mobile terminal as an example, Figure 1 This is a hardware structure block diagram of a mobile terminal for a fault detection method of a urea injection system according to an embodiment of the present invention. Figure 1 As shown, a mobile terminal may include one or more ( Figure 1 Only one is shown in the diagram. A processor 102 (which may include, but is not limited to, a microprocessor MCU or a programmable logic device FPGA, etc.) and a memory 104 for storing data are also shown. The mobile terminal may further include a transmission device 106 for communication functions and an input / output device 108. Those skilled in the art will understand that... Figure 1 The structure shown is for illustrative purposes only and does not limit the structure of the mobile terminal described above. For example, the mobile terminal may also include components that are more... Figure 1 The more or fewer components shown, or having the same Figure 1 The different configurations shown.

[0033] The memory 104 can be used to store computer programs, such as application software programs and modules, like the computer program corresponding to the fault detection method of the urea injection system in this embodiment of the invention. The processor 102 executes various functional applications and data processing by running the computer program stored in the memory 104, thereby implementing the above-described method. The memory 104 may include high-speed random access memory, and may also include non-volatile memory, such as one or more magnetic storage devices, flash memory, or other non-volatile solid-state memory. In some instances, the memory 104 may further include memory remotely located relative to the processor 102, and these remote memories can be connected to the mobile terminal via a network. Examples of the above-described networks include, but are not limited to, the Internet, corporate intranets, local area networks, mobile communication networks, and combinations thereof. The transmission device 106 is used to receive or send data via a network. Specific examples of the above-described networks may include wireless networks provided by the mobile terminal's communication provider. In one example, the transmission device 106 includes a network interface controller (NIC), which can be connected to other network devices via a base station to communicate with the Internet. In one example, the transmission device 106 may be a radio frequency (RF) module, which is used to communicate with the Internet wirelessly.

[0034] This embodiment provides a fault detection method for a urea injection system running on a mobile terminal, computer terminal, or similar computing device. It should be noted that the steps shown in the flowchart in the accompanying drawings can be executed in a computer system such as a set of computer-executable instructions. Although a logical order is shown in the flowchart, in some cases, the steps shown or described may be executed in a different order than that shown here.

[0035] like Figure 2 As shown, the fault detection method for the urea injection system is applied to a dual-SCR urea system. The dual-SCR urea system includes a first SCR mixer and a second SCR mixer arranged in series. The first SCR mixer includes a first urea nozzle 10 and a first SCR 20. The second SCR mixer includes a second urea nozzle 30 and a second SCR 40. The dual-SCR urea system also includes a urea pump 50 that is connected to the first urea nozzle and the second urea nozzle.

[0036] Specifically, the urea pump can be connected to the first urea nozzle and the second urea nozzle through separate pipelines, or the urea pump can be connected to the first urea nozzle and the second urea nozzle through a pipeline and a three-way valve.

[0037] Figure 3 This is a flowchart of a fault detection method for a urea injection system according to an embodiment of this application. Figure 3 As shown, the method includes the following steps:

[0038] Step S301: If the dual-SCR urea system meets the test conditions, control the dual-SCR urea system to enter the test phase. The test conditions include at least one of the following: no urea supply failure in the dual-SCR urea system, the cumulative urea injection amount after the dual-SCR urea system enters the injection phase is greater than the injection amount threshold, and no fault test has been performed in this driving cycle.

[0039] Among them, "no urea supply failure" in the dual-SCR urea system means that normal urea supply can be achieved.

[0040] Specifically, the above-mentioned spray volume threshold is set to 500g, but it can be adjusted according to the actual situation.

[0041] The above test conditions also include: no related faults in the injection system; related faults include defrosting-related faults and power supply-related faults.

[0042] The above-mentioned control of the dual-SCR urea system to enter the testing phase under the condition that the testing conditions are met is to ensure the accuracy of subsequent tests. If the testing phase is entered without meeting the testing conditions, potential faults may affect the determination of subsequent faults such as leaks.

[0043] Step S302: After the dual SCR urea system enters the testing phase, the first urea nozzle and the second urea nozzle are stopped from spraying. The pump pressure of the urea pump is maintained at the preset pump pressure using a preset control algorithm. The urea pump is then controlled using a constant value control algorithm, and the first pump pressure drop within the first preset time period is obtained. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual SCR urea system has no leakage fault.

[0044] Among them, the preset control algorithm can be an intelligent control algorithm such as PID control algorithm. After the first urea nozzle and the second urea nozzle stop spraying, the pump pressure of the urea pump is maintained at the preset pump pressure. The purpose is to quickly maintain the pump pressure of the urea pump at the preset pump pressure by closing the first urea nozzle and the second urea nozzle.

[0045] Specifically, the preset pump pressure is set to 9000 hPa, but it can be adjusted according to actual conditions.

[0046] Specifically, the aforementioned pressure drop preset value is related to the length of the first preset time period;

[0047] The constant value in the constant value control algorithm includes parameters such as the constant motor speed. Ideally, if the constant value control algorithm is used, the pump pressure of the urea pump should remain constant. However, due to the influence of leakage, this constant phenomenon will be broken. Therefore, when the pressure drop of the first pump is less than the preset pressure drop value, it is possible to determine that there is no leakage fault in the dual SCR urea system.

[0048] Specifically, the first preset time period can be selected as 1 second, but it can be adjusted according to the actual situation.

[0049] The fault detection method for a urea injection system disclosed in this application involves controlling the dual-SCR urea system to enter a testing phase when the testing conditions are met. After entering the testing phase, the first and second urea nozzles are stopped from injecting. A preset control algorithm is used to maintain the urea pump pressure at a preset pressure. A constant-value control algorithm is then used to control the urea pump and acquire the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than a preset value, it is determined that the dual-SCR urea system has no leakage fault. The method involves entering the testing phase when the testing conditions are met, and during the testing phase, the impact on the urea pump pressure is reduced by closing the first and second urea nozzles. The change in the urea pump pressure is then observed to determine whether a leakage fault exists in the dual-SCR urea system. This achieves accurate determination of leak-free faults.

[0050] In this embodiment of the application, after controlling the urea pump with a constant value control algorithm and obtaining the first pump pressure drop within a first preset time period, the method further includes:

[0051] When the pressure drop of the first pump is greater than or equal to the preset pressure drop value, the preset control algorithm is used to control the pump pressure of the urea pump to rise to the sum of the preset pump pressure and the preset pressure drop value. Then, the constant value control algorithm is used to control the urea pump and obtain the pressure drop of the second pump within the second preset time period.

[0052] Specifically, the second preset time period can be selected as 1 second, but it can be adjusted according to the actual situation.

[0053] If the pressure drop of the second pump is less than the preset pressure drop value, it is determined that there is no leakage fault in the dual-SCR urea system;

[0054] If the pressure drop of the second pump is greater than or equal to the preset pressure drop value, it is determined that there is a leakage fault in the dual SCR urea system.

[0055] In other words, even if the pressure drop of the first pump is greater than or equal to the preset pressure drop value, it cannot be directly determined that there is a leakage fault. It is necessary to continue to increase the pump pressure to the sum of the preset pump pressure and the preset pressure drop value, that is, to a pump pressure higher than the preset pump pressure, and then obtain the pump pressure drop again. If the pump pressure drop obtained again is less than the preset pressure drop value, it is determined that there is no leakage fault in the dual SCR urea system. If the pump pressure drop obtained again is greater than or equal to the preset pressure drop value, it is determined that there is a leakage fault in the dual SCR urea system. This ensures the accurate determination of whether there is a leakage fault in the dual SCR urea system and avoids the influence of disturbances causing the pressure drop of the first pump to be greater than or equal to the preset pressure drop value.

[0056] Of course, you can continue to increase the pump pressure to a higher level to determine if there is a leakage fault, for example, by determining it through three pump pressure drops, four pump pressure drops, and five pump pressure drops.

[0057] Of course, you can also determine whether there is a leakage fault by observing the pump pressure drop after maintaining the preset pump pressure multiple times.

[0058] Furthermore, the method also includes:

[0059] After the dual-SCR urea system has no leakage faults and the pump pressure of the urea pump is maintained at the preset pump pressure, the dual-SCR urea system is controlled to enter the first sub-test stage. In the first sub-test stage, the first urea nozzle sprays at a preset duty cycle for a third preset time period and then stops spraying, while the second urea nozzle does not spray.

[0060] Specifically, the preset duty cycle is set to the duty cycle of the urea pump motor when it is not injecting. Of course, it can be adjusted according to the actual situation.

[0061] Specifically, the third preset time period can be selected as 1 second, but it can be adjusted according to the actual situation.

[0062] As mentioned above, the second urea nozzle does not spray during the first sub-test stage, meaning that the second urea nozzle does not affect the pump pressure during the first sub-test stage.

[0063] Among them, the determination of whether there is nozzle blockage is only carried out after confirming that there is no leakage fault in the dual SCR urea system. This is to prevent leakage from affecting the determination of nozzle blockage. Specifically, leakage can be determined before each nozzle blockage determination, or multiple nozzle blockage determinations can be carried out after a single leakage determination, or a leakage determination can be carried out once within a certain period of time.

[0064] Obtain the third pump pressure drop in the first sub-test phase. The third pump pressure drop is the pump pressure at the moment when the first urea nozzle stops spraying relative to the preset pump pressure.

[0065] After the first sub-test phase ends, the pump pressure of the urea pump is increased to the preset pump pressure, and then the dual SCR urea system is controlled to enter the second sub-test phase. In the second sub-test phase, the second urea nozzle sprays at a preset duty cycle for a third preset time period and then stops spraying, while the first urea nozzle does not spray.

[0066] As mentioned above, the first urea nozzle does not spray during the second sub-test stage, meaning that the first urea nozzle does not affect the pump pressure during the second sub-test stage.

[0067] Obtain the fourth pump pressure drop in the second sub-test phase. The fourth pump pressure drop is the pump pressure at the moment when the second urea nozzle stops spraying, relative to the preset pump pressure.

[0068] The presence of nozzle blockage is determined by the ratio of the pressure drop of the third pump to that of the fourth pump.

[0069] In this embodiment, by performing a first sub-test stage and a second sub-test stage, the effects of the first urea nozzle on the pump pressure and the second urea nozzle on the pump pressure are considered respectively. If there is no nozzle blockage fault, that is, there is no difference in the spray of the first urea nozzle and the second urea nozzle, the ratio of the pressure drop of the third pump and the pressure drop of the fourth pump should be equal to 1. If there is a difference, the ratio of the pressure drop of the third pump and the pressure drop of the fourth pump will not be equal to 1. Then, based on the ratio of the pressure drop of the third pump and the pressure drop of the fourth pump, it is determined whether there is a nozzle blockage fault.

[0070] Specifically, such as Figure 4 As shown, the test phase usually starts from the idle phase, and after entering the test phase, it goes through the pressure phase to enter the first sub-test phase and the second sub-test phase.

[0071] In this embodiment of the application, determining whether a nozzle blockage fault exists based on the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump includes:

[0072] Obtain the difference between the first ratio and the second ratio. The first ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in this driving cycle, and the second ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the previous driving cycle.

[0073] If the difference between the first ratio and the second ratio is less than the difference threshold, it is determined that there is no nozzle blockage fault.

[0074] Specifically, the difference threshold is determined according to different configurations, including the performance parameters of the first urea nozzle and the second urea nozzle.

[0075] As shown above, if the difference between the ratios of the pressure drops of the third and fourth pumps measured in two separate measurements is less than the difference threshold, it is determined that there is no nozzle blockage fault.

[0076] In this embodiment of the application, the method further includes:

[0077] If the difference between the first ratio and the second ratio is greater than or equal to the difference threshold, the average of the first ratio and the second ratio is updated to the ratio of the third pump pressure drop and the fourth pump pressure drop measured in the last driving cycle.

[0078] It also includes: storing the updated ratio of the third pump pressure drop to the fourth pump pressure drop in an array;

[0079] The method also includes: measuring the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump multiple times in one driving cycle; if the difference between two adjacent measurements is greater than the difference threshold, the average of the two measurements is updated as the comparison ratio, and the comparison ratio is stored in an array, and the upper limit of the array's storage space is set, for example, to 10, that is, at most 10 updated ratios can be stored, which limits the upper limit of the number of times the ratio can be obtained.

[0080] like Figure 5 As shown, the method also includes:

[0081] Step S501: If the difference between the first ratio and the second ratio is greater than or equal to the difference threshold, execute the first acquisition step: control the dual SCR urea system to enter the first sub-test stage and the second sub-test stage again to acquire the pressure drop of the third pump and the pressure drop of the fourth pump again.

[0082] Step S502: Second acquisition step: Obtain the average value of the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump in this driving cycle;

[0083] Step S503: If the absolute value of the difference between the ratio of the currently acquired pressure drop of the third pump and the pressure drop of the fourth pump and the average value is less than the difference threshold, it is determined that there is no injection error between the first urea nozzle and the second urea nozzle at the current moment.

[0084] In other words, if the difference between the first ratio and the second ratio is greater than or equal to a threshold difference, the pressure drop of the third pump and the pressure drop of the fourth pump are obtained again, along with the average of all ratios of the third pump pressure drop and the fourth pump pressure drop within the current driving cycle. The absolute value of the difference between the obtained ratio and the average value is then calculated. If this difference is less than the threshold difference, it is determined that there is no injection error between the first urea nozzle and the second urea nozzle at the current moment. This prevents the difference between the first ratio and the second ratio from exceeding the threshold difference due to disturbances, thus achieving accurate judgment.

[0085] Furthermore, the method also includes: if the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is greater than or equal to the difference threshold, repeating the first acquisition step and the second acquisition step at least once in sequence until at least one of the following conditions is met: the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is less than the difference threshold, or the number of tests reaches the upper limit value.

[0086] In other words, if the absolute value of the difference between the ratio of the third pump pressure drop and the fourth pump pressure drop obtained again and the average value is still greater than or equal to the difference threshold, then the first and second acquisition steps should be repeated until the difference threshold is met or the maximum number of tests is reached and the repetition stops.

[0087] As above, if, even after reaching the maximum number of tests, the absolute value of the difference between the ratio of the pressure drop of the third pump and the pressure drop of the fourth pump and the average value is still less than the difference threshold, it is determined that the consistency deviation between the two nozzles is too large and cannot meet the usage requirements, and the calculation will not be repeated.

[0088] Furthermore, the method also includes:

[0089] According to the formula Determine the mass flow rate ratio for this driving cycle, where r std This represents the mass flow rate ratio, N represents the total number of tests performed in this driving cycle, and each test includes a first sub-test phase and a second sub-test phase, r i denoted as the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump obtained in the i-th test, and r represents the average value of all the ratios of the pressure drop of the third pump to the pressure drop of the fourth pump obtained in this driving cycle.

[0090] This means that the mass flow rate ratio can be accurately determined through multiple tests. If the mass flow rate ratio is not equal to 1, the blockage can be corrected by multiplying the mass flow rate ratio by the flow rate. In other words, the injection can be corrected by increasing the opening without increasing the injection volume. It can also be used to calculate the life cycle aging correction factor.

[0091] To enable those skilled in the art to better understand the technical solution of this application, the implementation process of the fault detection method for the urea injection system of this application will be described in detail below with reference to specific embodiments.

[0092] This embodiment relates to a specific fault detection method for a urea injection system, including the following steps:

[0093] Step S1: When the injection system is in the injection phase, the test begins when the following conditions are met: there are no related faults in the urea supply system and the injection system, the cumulative injection volume is greater than the injection volume threshold after entering the normal injection phase, and no fault test has been performed in this driving cycle.

[0094] Step S2: First, perform a leak detection on the injection pressure pipeline. When the test conditions are met, the system transitions from the idle phase to the test phase. Upon first entering this phase, the first and second urea nozzles stop injecting. After maintaining the preset pump pressure P1, the pump stops operating, and pump pressure regulation is no longer involved (i.e., the PID algorithm is no longer used for regulation). Observe the pressure drop within the first preset time period T1. If ΔP < P thd If ΔP ≥ P, then no leakage is considered to have occurred; otherwise, ΔP ≥ P. thd Then the pump pressure is adjusted to reach P1+P thd After the pump stops operating, observe the pressure drop in the pressure pipe during the second preset time period T2. If ΔP < P thd If the value is positive, it is considered that there is no leakage; otherwise, it is considered that there is a slight leakage.

[0095] Step S3: When it is determined that there is no leakage in the injection pipeline, a nozzle blockage detection is performed. When the pump pressure is equal to the preset pump pressure, the first sub-test stage is entered. If the pump pressure is less than the preset pump pressure, pressurization is performed first to maintain the pressure at the preset pump pressure before entering the first sub-test stage of injection. In this stage, the first urea nozzle is injected at a fixed duty cycle for a third preset time period and then the nozzle is closed. Then, pressurization is performed until the set pressure is reached, and then the process jumps to the second sub-test stage. In the second sub-test stage, the second urea nozzle is injected at a fixed duty cycle for a third preset time period and then the nozzle is closed. At the same time, the pressure drops ΔP1 and ΔP2 at the beginning and end of the first and second sub-test stages are recorded.

[0096] Step S4: After the first and second sub-test phases are completed, record the pressure difference ratio r between the two. p This represents the mass flow rate ratio of the two nozzles, and the measured pressure difference ratio r is used to represent this ratio. p The pressure difference r compared to the previously measured pressure p_old (Initial value is 1) The difference is calculated. When the difference is less than the difference threshold, that is, the mass flow deviation of the two nozzles is within the allowable range, it indicates that the test is passed.

[0097]

[0098] Step S5: If the deviation of the calculated mass flow rate ratio is not within the allowable range, then update r. p_old r p_old =(r p +r p_old ) / 2, r p_old Store the data in non-volatile memory and in the first position A1 of array A (dimension set to within 10). Further reliability testing is required; repeat step S3 to recalculate the pressure difference ratio between the two nozzles and store it in array A. During this process, calculate all pressure difference ratios r for this driving cycle. p The average number r p-min If r d =r p-m i n -r p If the absolute value is less than the threshold, the test can still be considered passed and there is no spraying error between the two nozzles. If the result is still greater than the difference threshold, then continue to repeat steps S3 and S5 until the test is passed or the test upper limit (the upper limit of the array) is reached, and a fault is reported, indicating that the consistency deviation between the two nozzles is too large and cannot meet the usage requirements. The calculation will not be repeated.

[0099] Step S6: In this step, after the test is passed, the effective nozzle mass flow ratio is calculated. The main purpose is to eliminate outliers that occurred during the test and average the effective values ​​to obtain the effective mass flow ratio for this driving cycle, thereby correcting for the aging phenomenon of the nozzle throughout its life cycle. The standard deviation is calculated using Formula 2. The difference between the pressure difference ratio in the array and the average value is taken. If the absolute value is less than the standard deviation, the data is considered valid; otherwise, it is invalid. The effective values ​​are averaged again to obtain the final mass flow ratio.

[0100]

[0101] Where, r std The mass flow rate ratio is represented by N, which represents the total number of tests performed in this driving cycle. Each test includes the first sub-test phase and the second sub-test phase. r i This represents the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump obtained in the i-th test. This represents the average of the ratios of the pressure drops of the third pump and the fourth pump obtained in this driving cycle.

[0102] This application embodiment enables pipeline airtightness detection, spray consistency between dual nozzles, and life-cycle nozzle aging and clogging detection, ensuring component reliability.

[0103] It should be noted that the steps shown in the flowchart in 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 may be executed in a different order than that shown here.

[0104] This application also provides a fault detection device for a urea injection system. It should be noted that this fault detection device can be used to execute the fault detection method for a urea injection system provided in this application. This device is used to implement the above embodiments and preferred embodiments; details already described will not be repeated. As used below, the term "module" can refer to a combination of software and / or hardware that performs a predetermined function. Although the device described in the following embodiments is preferably implemented in software, hardware implementation, or a combination of software and hardware, is also possible and contemplated.

[0105] The following describes the fault detection device for the urea injection system provided in the embodiments of this application.

[0106] Figure 6 This is a schematic diagram of a fault detection device for a urea injection system according to an embodiment of this application. Figure 6 As shown, the device includes:

[0107] The first control unit 61 is used to control the dual SCR urea system to enter the test phase when the dual SCR urea system meets the test conditions. The test conditions include at least one of the following: no urea supply failure in the dual SCR urea system, the cumulative urea injection amount after the dual SCR urea system enters the injection phase is greater than the injection amount threshold, and no fault test has been performed in this driving cycle.

[0108] The processing unit 62 is used to control the dual SCR urea system to enter the test phase, and after controlling the first urea nozzle and the second urea nozzle to stop spraying, it uses a preset control algorithm to control the urea pump pressure to maintain at a preset pump pressure, and uses a constant value control algorithm to control the urea pump and obtain the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than the preset pressure drop value, it is determined that there is no leakage fault in the dual SCR urea system.

[0109] The fault detection device for the urea injection system disclosed in this application comprises a first control unit that, when the dual-SCR urea system meets the test conditions, controls the dual-SCR urea system to enter the test phase. After the processing unit controls the dual-SCR urea system to enter the test phase, it controls the first and second urea nozzles to stop injection and then uses a preset control algorithm to maintain the urea pump pressure at a preset pump pressure. A constant value control algorithm is then used to control the urea pump and acquire the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than a preset pressure drop value, it is determined that the dual-SCR urea system has no leakage fault. The device enters the test phase when the test conditions are met, and during the test phase, the impact on the urea pump pressure is reduced by closing the first and second urea nozzles. Then, the change in the urea pump pressure is observed to determine whether a leakage fault exists in the dual-SCR urea system. This achieves accurate determination of leak-free faults.

[0110] In this embodiment, the device further includes a second control unit, a first determining unit, and a second determining unit. The second control unit is used to control the urea pump using a constant value control algorithm and obtain the first pump pressure drop within a first preset time period. If the first pump pressure drop is greater than or equal to a preset pressure drop value, the control unit uses a preset control algorithm to control the urea pump pressure to rise to the sum of the preset pump pressure and the preset pressure drop value. Then, it uses a constant value control algorithm to control the urea pump and obtain the second pump pressure drop within a second preset time period. The first determining unit is used to determine that the dual-SCR urea system has no leakage fault if the second pump pressure drop is less than the preset pressure drop value. The second determining unit is used to determine that the dual-SCR urea system has a leakage fault if the second pump pressure drop is greater than or equal to the preset pressure drop value. In other words, even if the pressure drop of the first pump is greater than or equal to the preset pressure drop value, it cannot be directly determined that there is a leakage fault. It is necessary to continue to increase the pump pressure to the sum of the preset pump pressure and the preset pressure drop value, that is, to a pump pressure higher than the preset pump pressure, and then obtain the pump pressure drop again. If the pump pressure drop obtained again is less than the preset pressure drop value, it is determined that there is no leakage fault in the dual SCR urea system. If the pump pressure drop obtained again is greater than or equal to the preset pressure drop value, it is determined that there is a leakage fault in the dual SCR urea system. This ensures the accurate determination of whether there is a leakage fault in the dual SCR urea system and avoids the influence of disturbances causing the pressure drop of the first pump to be greater than or equal to the preset pressure drop value.

[0111] In this embodiment, the device further includes a third control unit, a first acquisition unit, a fourth control unit, a second acquisition unit, and a third determination unit. The third control unit is used to control the dual-SCR urea system to enter a first sub-test stage after ensuring there is no leakage fault in the dual-SCR urea system and maintaining the urea pump pressure at a preset pump pressure. In the first sub-test stage, the first urea nozzle sprays at a preset duty cycle for a third preset time period and then stops spraying, while the second urea nozzle does not spray. The first acquisition unit is used to acquire the third pump pressure drop in the first sub-test stage, where the third pump pressure drop is relative to the pump pressure at the moment the first urea nozzle stops spraying. The first sub-test phase involves a pressure drop across the first and second sub-test phases. The fourth control unit controls the urea pump pressure to increase to the preset pump pressure after the first sub-test phase, then controls the dual-SCR urea system to enter the second sub-test phase. During the second sub-test phase, the second urea nozzle sprays at a preset duty cycle for a third preset time period and then stops spraying, while the first urea nozzle does not spray. The second acquisition unit acquires the fourth pump pressure drop during the second sub-test phase, which is the pressure drop of the pump pressure at the moment the second urea nozzle stops spraying relative to the preset pump pressure. The third determination unit determines whether a nozzle blockage fault exists based on the ratio of the third pump pressure drop to the fourth pump pressure drop. By conducting the first and second sub-test phases, considering the effects of the first and second urea nozzles on the pump pressure, if there is no nozzle blockage fault (i.e., there is no difference in spraying between the first and second urea nozzles), the ratio of the third pump pressure drop to the fourth pump pressure drop should be equal to 1. If there is a difference, the ratio of the third pump pressure drop to the fourth pump pressure drop will not be equal to 1. Therefore, the presence of a nozzle blockage fault is determined based on the ratio of the third pump pressure drop to the fourth pump pressure drop.

[0112] In this embodiment, the third determining unit includes an acquisition module and a determining module. The acquisition module is used to acquire the difference between a first ratio and a second ratio. The first ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the current driving cycle, and the second ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the previous driving cycle. The determining module is used to determine that there is no nozzle blockage fault if the difference between the first ratio and the second ratio is less than a difference threshold. As described above, the absence of a nozzle blockage fault is determined based on the fact that the difference between the ratios of the pressure drops of the third pump and the fourth pump measured in two consecutive measurements is less than a difference threshold.

[0113] In this embodiment of the application, the device further includes an updating unit, which is used to update the average of the first ratio and the second ratio to the ratio of the third pump pressure drop and the fourth pump pressure drop measured in the previous driving cycle when the difference between the first ratio and the second ratio is greater than or equal to the difference threshold.

[0114] In this embodiment of the application, the device further includes a third acquisition unit, a fourth acquisition unit, and a fourth determination unit. The third acquisition unit is used to perform a first acquisition step when the difference between the first ratio and the second ratio is greater than or equal to a difference threshold: control the dual SCR urea system to enter the first sub-test stage and the second sub-test stage again to acquire the third pump pressure drop and the fourth pump pressure drop again. The fourth acquisition unit is used to perform a second acquisition step: acquire the average value of all ratios of the third pump pressure drop and the fourth pump pressure drop in this driving cycle. The fourth determination unit is used to determine that there is no injection error of the first urea nozzle and the second urea nozzle at the current moment when the absolute value of the difference between the currently acquired ratio of the third pump pressure drop and the fourth pump pressure drop and the average value is less than a difference threshold. In other words, if the difference between the first ratio and the second ratio is greater than or equal to a threshold difference, the pressure drop of the third pump and the pressure drop of the fourth pump are obtained again, along with the average of all ratios of the third pump pressure drop and the fourth pump pressure drop within the current driving cycle. The absolute value of the difference between the obtained ratio and the average value is then calculated. If this difference is less than the threshold difference, it is determined that there is no injection error between the first urea nozzle and the second urea nozzle at the current moment. This prevents the difference between the first ratio and the second ratio from exceeding the threshold difference due to disturbances, thus achieving accurate judgment.

[0115] In this embodiment, the device further includes a repeating unit. The repeating unit is configured to repeat the first acquisition step and the second acquisition step at least once, provided that the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is greater than or equal to a difference threshold. This continues until at least one of the following conditions is met: the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is less than the difference threshold; or the number of tests reaches an upper limit. In other words, if the absolute value of the difference between the ratio of the third pump pressure drop and the fourth pump pressure drop and the average value is still greater than or equal to the difference threshold, then the first acquisition step and the second acquisition step are repeated until the difference threshold is met, or the maximum number of tests is reached and the repetition stops.

[0116] In this embodiment of the application, the device further includes a fifth determining unit, which is used to determine the formula. Determine the mass flow rate ratio for this driving cycle, where r std This represents the mass flow rate ratio, N represents the total number of tests performed in this driving cycle, and each test includes a first sub-test phase and a second sub-test phase, r i This represents the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump obtained in the i-th test. This represents the average of the ratios of the pressure drops of the third and fourth pumps obtained in this driving cycle. It achieves precise determination of the mass flow ratio through multiple tests. If the mass flow ratio is not equal to 1, it can be multiplied by the flow rate to correct for blockages. This is achieved by increasing the injection opening without increasing the injection volume, and can also be used to calculate the life cycle aging correction factor.

[0117] The fault detection device for the urea injection system includes a processor and a memory. The aforementioned first control unit and processing unit are all stored as program units in the memory, and the processor executes the program units stored in the memory to achieve the corresponding functions. All of the above modules are located in the same processor; alternatively, the above modules may be located in different processors in any combination.

[0118] The processor contains a kernel, which retrieves the corresponding program units from memory. One or more kernels can be configured, and adjusting kernel parameters can address the lack of a precise method for detecting abnormal faults in dual-injection urea systems in related technologies.

[0119] The memory may include non-permanent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, such as read-only memory (ROM) or flash RAM, and the memory includes at least one memory chip.

[0120] This invention provides an electronic device, including: one or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, and the one or more programs include a fault detection method for performing any one of the following urea injection systems.

[0121] This invention provides a computer-readable storage medium including a stored program, wherein, when the program is executed, it controls the device where the computer-readable storage medium is located to perform a fault detection method for a urea injection system.

[0122] Specifically, the fault detection methods for urea injection systems include:

[0123] Step S301: If the dual-SCR urea system meets the test conditions, control the dual-SCR urea system to enter the test phase. The test conditions include at least one of the following: no urea supply failure in the dual-SCR urea system, the cumulative urea injection amount after the dual-SCR urea system enters the injection phase is greater than the injection amount threshold, and no fault test has been performed in this driving cycle.

[0124] Step S302: After the dual SCR urea system enters the testing phase, the first urea nozzle and the second urea nozzle are stopped from spraying. The pump pressure of the urea pump is maintained at the preset pump pressure using a preset control algorithm. The urea pump is then controlled using a constant value control algorithm, and the first pump pressure drop within the first preset time period is obtained. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual SCR urea system has no leakage fault.

[0125] This invention provides a processor for running a program, wherein the program executes a fault detection method for the urea injection system.

[0126] Specifically, the fault detection methods for urea injection systems include:

[0127] Step S301: If the dual-SCR urea system meets the test conditions, control the dual-SCR urea system to enter the test phase. The test conditions include at least one of the following: no urea supply failure in the dual-SCR urea system, the cumulative urea injection amount after the dual-SCR urea system enters the injection phase is greater than the injection amount threshold, and no fault test has been performed in this driving cycle.

[0128] Step S302: After the dual SCR urea system enters the testing phase, the first urea nozzle and the second urea nozzle are stopped from spraying. The pump pressure of the urea pump is maintained at the preset pump pressure using a preset control algorithm. The urea pump is then controlled using a constant value control algorithm, and the first pump pressure drop within the first preset time period is obtained. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual SCR urea system has no leakage fault.

[0129] This invention provides a device, which includes a processor, a memory, and a program stored in the memory and executable on the processor. When the processor executes the program, it performs at least the following steps: The device in this article may be a server, PC, PAD, mobile phone, etc.

[0130] Step S301: If the dual-SCR urea system meets the test conditions, control the dual-SCR urea system to enter the test phase. The test conditions include at least one of the following: no urea supply failure in the dual-SCR urea system, the cumulative urea injection amount after the dual-SCR urea system enters the injection phase is greater than the injection amount threshold, and no fault test has been performed in this driving cycle.

[0131] Step S302: After the dual SCR urea system enters the testing phase, the first urea nozzle and the second urea nozzle are stopped from spraying. The pump pressure of the urea pump is maintained at the preset pump pressure using a preset control algorithm. The urea pump is then controlled using a constant value control algorithm, and the first pump pressure drop within the first preset time period is obtained. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual SCR urea system has no leakage fault.

[0132] This application also provides a computer program product, which, when executed on a data processing device, is suitable for executing an initialization program having at least the following method steps:

[0133] Step S301: If the dual-SCR urea system meets the test conditions, control the dual-SCR urea system to enter the test phase. The test conditions include at least one of the following: no urea supply failure in the dual-SCR urea system, the cumulative urea injection amount after the dual-SCR urea system enters the injection phase is greater than the injection amount threshold, and no fault test has been performed in this driving cycle.

[0134] Step S302: After the dual SCR urea system enters the testing phase, the first urea nozzle and the second urea nozzle are stopped from spraying. The pump pressure of the urea pump is maintained at the preset pump pressure using a preset control algorithm. The urea pump is then controlled using a constant value control algorithm, and the first pump pressure drop within the first preset time period is obtained. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual SCR urea system has no leakage fault.

[0135] It is obvious to those skilled in the art that the modules or steps of the present invention described above can be implemented using general-purpose computing devices. They can be centralized on a single computing device or distributed across a network of multiple computing devices. They can be implemented using computer-executable program code, and thus can be stored in a storage device for execution by a computing device. In some cases, the steps shown or described can be performed in a different order than those described herein, or they can be fabricated as separate integrated circuit modules, or multiple modules or steps can be fabricated as a single integrated circuit module. Thus, the present invention is not limited to any particular combination of hardware and software.

[0136] Those skilled in the art will understand that embodiments of this application can be provided as methods, systems, or computer program products. Therefore, this application can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, this application can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0137] This application is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of this application. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart... Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0138] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0139] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0140] In a typical configuration, a computing device includes one or more processors (CPU), input / output interfaces, network interfaces, and memory.

[0141] Memory may include non-persistent memory in computer-readable media, such as random access memory (RAM) and / or non-volatile memory, like read-only memory (ROM) or flash RAM. Memory is an example of computer-readable media.

[0142] Computer-readable media includes both permanent and non-permanent, removable and non-removable media that can store information using any method or technology. Information can be computer-readable instructions, data structures, modules of programs, 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, CD-ROM, digital versatile optical disc (DVD) or other optical storage, magnetic tape, magnetic magnetic disk storage or other magnetic storage devices, or any other non-transferable medium that can be used to store information accessible by a computing device. As defined herein, computer-readable media does not include transient computer-readable media, such as modulated data signals and carrier waves.

[0143] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such process, method, article, or apparatus. Unless otherwise specified, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes that element.

[0144] As can be seen from the above description, the embodiments of this application achieve the following technical effects:

[0145] 1) The fault detection method for the urea injection system of this application involves controlling the dual-SCR urea system to enter the testing phase when the testing conditions are met. After the dual-SCR urea system enters the testing phase, the first and second urea nozzles are stopped from injecting. A preset control algorithm is used to maintain the pump pressure of the urea pump at a preset pump pressure. A constant value control algorithm is then used to control the urea pump and obtain the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than a preset pressure drop value, it is determined that there is no leakage fault in the dual-SCR urea system. The method involves entering the testing phase when the testing conditions are met, and during the testing phase, the impact on the pump pressure of the urea pump is reduced by closing the first and second urea nozzles. Then, the change in the pump pressure of the urea pump is observed to determine whether there is a leakage fault in the dual-SCR urea system. This achieves accurate determination of leakage-free faults.

[0146] 2) The fault detection device for the urea injection system of this application includes a first control unit that, when the dual-SCR urea system meets the test conditions, controls the dual-SCR urea system to enter the test phase. After the processing unit controls the dual-SCR urea system to enter the test phase, it controls the first and second urea nozzles to stop injection and then uses a preset control algorithm to maintain the urea pump pressure at a preset pump pressure. A constant value control algorithm is then used to control the urea pump and acquire the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than a preset pressure drop value, it is determined that the dual-SCR urea system has no leakage fault. The device enters the test phase when the test conditions are met. During the test phase, the first and second urea nozzles are closed to reduce the impact on the urea pump pressure. Then, the change in the urea pump pressure is observed to determine whether a leakage fault exists in the dual-SCR urea system. This achieves accurate determination of leak-free faults.

[0147] The above description is merely a preferred embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A fault detection method for a urea injection system, characterized in that, The urea injection system is a dual-SCR urea system, comprising a first SCR mixer and a second SCR mixer arranged in series. The first SCR mixer includes a first urea nozzle, and the second SCR mixer includes a second urea nozzle. The dual-SCR urea system further includes a urea pump communicating with the first urea nozzle and the second urea nozzle. When the dual-SCR urea system meets the test conditions, the dual-SCR urea system is controlled to enter the test phase. The test conditions include at least one of the following: the dual-SCR urea system has no urea supply failure, the cumulative urea injection volume of the dual-SCR urea system after entering the injection phase is greater than the injection volume threshold, and no fault test has been performed in this driving cycle. After the dual-SCR urea system enters the test phase, the first urea nozzle and the second urea nozzle are stopped from spraying. A preset control algorithm is used to control the pump pressure of the urea pump to be maintained at a preset pump pressure. A constant value control algorithm is used to control the urea pump and obtain the first pump pressure drop within a first preset time period. If the first pump pressure drop is less than the preset pressure drop value, it is determined that the dual-SCR urea system has no leakage fault. The method further includes: After the dual-SCR urea system has no leakage fault and the pump pressure of the urea pump is maintained at the preset pump pressure, the dual-SCR urea system is controlled to enter the first sub-test stage. In the first sub-test stage, the first urea nozzle sprays at a preset duty cycle for a third preset time period and then stops spraying, and the second urea nozzle does not spray. Obtain the third pump pressure drop during the first sub-test phase, wherein the third pump pressure drop is the pump pressure at the moment when the first urea nozzle stops spraying relative to the preset pump pressure; After the first sub-test phase ends, the pump pressure of the urea pump is increased to the preset pump pressure, and then the dual SCR urea system is controlled to enter the second sub-test phase. In the second sub-test phase, the second urea nozzle sprays at the preset duty cycle for a third preset time period and then stops spraying, and the first urea nozzle does not spray. Obtain the fourth pump pressure drop during the second sub-test phase, the fourth pump pressure drop being the pump pressure at the moment when the second urea nozzle stops spraying relative to the preset pump pressure; The presence of a nozzle blockage fault is determined based on the ratio of the pressure drop of the third pump to that of the fourth pump.

2. The method according to claim 1, characterized in that, After controlling the urea pump using a constant value control algorithm and obtaining the first pump pressure drop within a first preset time period, the method further includes: When the pressure drop of the first pump is greater than or equal to the preset pressure drop value, the preset control algorithm is used to control the pump pressure of the urea pump to rise to the sum of the preset pump pressure and the preset pressure drop value. Then, the constant value control algorithm is used to control the urea pump and obtain the pressure drop of the second pump within the second preset time period. If the pressure drop of the second pump is less than the preset pressure drop value, it is determined that the dual-SCR urea system has no leakage fault; If the pressure drop of the second pump is greater than or equal to the preset pressure drop value, it is determined that the dual-SCR urea system has a leakage fault.

3. The method according to claim 1, characterized in that, Based on the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump, determine whether a nozzle blockage fault exists, including: Obtain the difference between the first ratio and the second ratio, where the first ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the current driving cycle, and the second ratio is the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump measured in the previous driving cycle. If the difference between the first ratio and the second ratio is less than the difference threshold, it is determined that there is no nozzle blockage fault.

4. The method according to claim 3, characterized in that, The method further includes: If the difference between the first ratio and the second ratio is greater than or equal to the difference threshold, the average of the first ratio and the second ratio is updated to the ratio of the pressure drop of the third pump and the pressure drop of the fourth pump measured in the previous driving cycle.

5. The method according to claim 3 or 4, characterized in that, The method further includes: If the difference between the first ratio and the second ratio is greater than or equal to the difference threshold, the first acquisition step is executed: the dual SCR urea system is controlled to enter the first sub-test stage and the second sub-test stage again to acquire the pressure drop of the third pump and the pressure drop of the fourth pump again. The second acquisition step: acquire the average value of the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump in the current driving cycle; If the absolute value of the difference between the ratio of the currently acquired pressure drop of the third pump and the pressure drop of the fourth pump and the average value is less than the difference threshold, it is determined that there is no injection error in the first urea nozzle and the second urea nozzle at the current moment.

6. The method according to claim 5, characterized in that, The method further includes: If the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is greater than or equal to the difference threshold, the first acquisition step and the second acquisition step are repeated at least once until at least one of the following conditions is met: the absolute value of the difference between the ratio of the currently acquired third pump pressure drop and the fourth pump pressure drop and the average value is less than the difference threshold, or the number of tests reaches the upper limit value.

7. The method according to claim 2, characterized in that, The method further includes: According to the formula Determine the mass flow rate ratio for this driving cycle, wherein, The mass flow rate ratio is represented by N, which represents the total number of tests performed in this driving cycle. Each test includes the first sub-test phase and the second sub-test phase. This represents the ratio of the pressure drop of the third pump to the pressure drop of the fourth pump obtained in the i-th test. This represents the average of the ratios of the pressure drops of the third pump and the fourth pump obtained in this driving cycle.

8. 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 containing the computer-readable storage medium to perform the fault detection method for the urea injection system according to any one of claims 1 to 7.

9. An electronic device, characterized in that, include: One or more processors, a memory, and one or more programs, wherein the one or more programs are stored in the memory and configured to be executed by the one or more processors, the one or more programs including a fault detection method for performing any one of claims 1 to 7 of a urea injection system.

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