Urea injection system fault diagnosis method, device and computer equipment

Abstract

The present application relates to a method, apparatus, computer device, storage medium, and computer program product for urea injection system fault diagnosis. The method comprises: obtaining the maximum and minimum urea line pressures of the urea injection system within an effective injection cycle; obtaining a maximum pressure drop value within each effective injection cycle based on the maximum and minimum urea line pressures within each effective injection cycle; comparing the maximum pressure drop value within each effective injection cycle with a standard pressure drop value to obtain a deviation corresponding to each effective injection cycle; and calculating the number of abnormal effective injection cycles represented by the deviations, and performing urea injection system fault diagnosis based on the number of abnormal effective injection cycles. This method can improve the efficiency of urea injection system fault diagnosis.

Description

Technical Field

[0001] The present application relates to the technical field of vehicle post-processing, and in particular to a method, device and computer equipment for diagnosing faults in a urea injection system. Background Art

[0002] With the development of vehicle aftertreatment technology, Selective Catalytic Reduction (SCR) technology has emerged. As a key component of the SCR system, the urea injection system reduces nitrogen oxides in vehicle exhaust into nitrogen and water through the action of a catalyst using injected urea. The proper functioning of the urea injection system directly affects the emission of nitrogen oxides in vehicle exhaust.

[0003] When diagnosing a urea injection system, traditional technology typically calculates actual urea consumption based on urea level changes and compares the actual urea consumption with the system's calculated consumption to determine if the system is faulty. This method requires a sufficiently large urea level change to complete the diagnosis, resulting in low diagnostic efficiency.

[0004] Therefore, how to improve the fault diagnosis efficiency of the urea injection system is an urgent problem to be solved. Summary of the Invention

[0005] Based on this, it is necessary to provide a urea injection system fault diagnosis method, device, computer equipment, computer-readable storage medium and computer program product that can improve fault diagnosis efficiency in response to the above technical problems.

[0006] In a first aspect, the present application provides a method for diagnosing a urea injection system fault. The method comprises:

[0007] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0008] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0009] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0010] The statistical deviation condition characterizes the number of abnormal valid injection cycles, based on which a fault diagnosis of the urea injection system is performed.

[0011] In one embodiment, the method further comprises:

[0012] Determine whether the power-on initialization of the engine management system is completed;

[0013] determining whether the urea solution and pipelines in the urea injection system are in an unfrozen state;

[0014] determining whether the urea injection system is in an injection state;

[0015] determining whether a urea line pressure sensor in the urea injection system is faulty;

[0016] If the power-on initialization of the engine management system is completed and continues for a preset time, the urea solution and the pipeline are in an unfrozen state within the preset time, the urea injection system is in an injection state within the preset time, and the urea pipeline pressure sensor has no fault within the preset time, then it is determined that the diagnosis enabling condition is met;

[0017] After the diagnosis enabling condition is met, the step of obtaining the maximum urea line pressure and the minimum urea line pressure of the urea injection system within the effective injection cycle is performed.

[0018] In one embodiment, the effective injection period is determined by:

[0019] Monitoring the nozzle opening time for a preset number of consecutive spray cycles;

[0020] If the nozzle opening time of the continuous preset number of injection cycles is within the preset range, the preset number of injection cycles and the injection cycles after the preset number of injection cycles are determined to be valid injection cycles.

[0021] In one embodiment, the method further comprises:

[0022] Get the nozzle opening time in each effective injection cycle;

[0023] The calibration chart is queried according to the nozzle opening time to obtain the standard pressure drop value corresponding to each effective injection cycle.

[0024] In one embodiment, the deviation condition includes a deviation value, the statistical deviation condition represents the number of abnormal effective injection cycles, and fault diagnosis of the urea injection system based on the number includes:

[0025] If the deviation value is greater than the first deviation threshold, determining the corresponding valid injection period as the first injection abnormality period;

[0026] If the deviation value is less than a second deviation threshold, determining the corresponding effective injection period as a second injection abnormality period; wherein the second deviation threshold is less than the first deviation threshold;

[0027] Counting a first number of first injection abnormality cycles, and counting a second number of second injection abnormality cycles;

[0028] Calculating a high pressure drop abnormality rate based on the first number and the total number of valid injection cycle counts, and calculating a low pressure drop abnormality rate based on the second number and the total number of valid injection cycle counts;

[0029] A fault diagnosis of the urea injection system is performed based on the excessively high pressure drop abnormal rate and the excessively low pressure drop abnormal rate.

[0030] In one embodiment, the fault diagnosis of the urea injection system according to the abnormal rate of excessively high pressure drop and the abnormal rate of excessively low pressure drop includes:

[0031] If the pressure drop abnormal rate exceeds a first abnormal threshold, it is determined that the urea nozzle of the urea injection system is clogged;

[0032] If the pressure drop abnormal rate exceeds a second abnormal threshold, the nitrogen oxide conversion rate is obtained. If the conversion rate is normal, it is determined that the urea nozzle is overspraying. If the conversion rate is less than the conversion rate threshold, it is determined that the urea filter is clogged.

[0033] In a second aspect, the present application further provides a urea injection system fault diagnosis device. The device comprises:

[0034] An acquisition module, used to acquire the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within an effective injection cycle;

[0035] a calculation module, configured to obtain a maximum pressure drop value within each effective injection cycle according to a maximum urea pipeline pressure and a minimum urea pipeline pressure within each effective injection cycle;

[0036] A comparison module is used to compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0037] The diagnosis module is configured to count the number of effective injection cycles in which the deviation indicates abnormality, and perform fault diagnosis of the urea injection system based on the number.

[0038] In a third aspect, the present application further provides a computer device. The computer device includes a memory and a processor, wherein the memory stores a computer program, and when the processor executes the computer program, the following steps are performed:

[0039] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0040] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0041] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0042] The statistical deviation condition characterizes the number of abnormal valid injection cycles, based on which a fault diagnosis of the urea injection system is performed.

[0043] In a fourth aspect, the present application further provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the following steps:

[0044] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0045] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0046] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0047] The statistical deviation condition characterizes the number of abnormal valid injection cycles, based on which a fault diagnosis of the urea injection system is performed.

[0048] In a fifth aspect, the present application further provides a computer program product. The computer program product includes a computer program that, when executed by a processor, implements the following steps:

[0049] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0050] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0051] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0052] The statistical deviation condition characterizes the number of abnormal valid injection cycles, based on which a fault diagnosis of the urea injection system is performed.

[0053] The above-mentioned urea injection system fault diagnosis method, apparatus, computer device, storage medium, and computer program product obtain the maximum and minimum urea line pressures of the urea injection system within an effective injection cycle, and based on the maximum and minimum urea line pressures within each effective injection cycle, obtain the maximum pressure drop value within each effective injection cycle. The maximum pressure drop value within each effective injection cycle is then compared with a standard pressure drop value to obtain the deviation corresponding to each effective injection cycle. The deviation is used to determine whether the actual urea consumption caused by the urea injection system fault is too high or too low. Finally, the number of effective injection cycles characterized by the deviation is counted, and urea injection system fault diagnosis is performed based on the counted number of cycles. Thus, by determining the deviation within a certain number of effective cycles, the cause of the urea injection system fault can be determined, thereby improving the efficiency of urea injection system fault diagnosis. BRIEF DESCRIPTION OF THE DRAWINGS

[0054] Figure 1 FIG. 1 is an application environment diagram of a urea injection system fault diagnosis method according to an embodiment;

[0055] Figure 2 is a schematic diagram of a urea injection system in one embodiment;

[0056] Figure 3 1 is a flow chart of a method for diagnosing a fault of a urea injection system according to an embodiment;

[0057] Figure 4 A schematic diagram of a process for performing fault diagnosis based on statistical quantities in one embodiment;

[0058] Figure 5 A schematic diagram of counting the number of effective injection cycles in one embodiment;

[0059] Figure 6 is a structural block diagram of a urea injection system fault diagnosis device in one embodiment;

[0060] Figure 7 FIG. 1 is a diagram showing the internal structure of a computer device in one embodiment.

[0061] Explanation of Figure Numbers

[0062] 100: target vehicle; 104: on-board controller; 106: computer equipment; 210: air tank; 220: intake valve; 230: urea tank; 240: liquid level float; 250: urea filter; 260: exhaust valve; 270: urea pipeline pressure sensor; 280: urea nozzle. DETAILED DESCRIPTION

[0063] In order to make the purpose, technical solutions and advantages of this application more clear, the following further describes this application in detail with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0064] It should be noted that the terms "comprises," "includes," "having," and any variations thereof, as used herein, are intended to cover non-exclusive inclusions. For example, a process, method, product, or apparatus that includes a series of steps or devices is not necessarily limited to the steps explicitly listed, but may also include other steps or devices that are not explicitly listed or that are inherent to the process, method, product, or apparatus. The term "and / or" as used herein includes any and all combinations of one or more of the relevant listed items.

[0065] Furthermore, the terms "first," "second," and the like are used herein to distinguish similar objects in terms of nomenclature, but these objects themselves are not limited by these terms. It should be understood that these terms are interchangeable where appropriate without departing from the scope of this application. For example, a "first deviation threshold" could be described as a "second deviation threshold," and similarly, a "second deviation threshold" could be described as a "first deviation threshold."

[0066] The urea injection system fault diagnosis method provided in the embodiment of the present application can be applied to Figure 1 In the application environment shown in FIG. , the onboard controller 104 is set on the target vehicle 100, and the onboard controller 104 can communicate with the computer device 106 through the network. The data storage system can store data that the computer device 106 needs to process. The data storage system can be integrated on the computer device 106, or placed on the cloud or other network servers. The target vehicle 100 is configured with Figure 2 The urea injection system shown includes an air reservoir 210, an air intake valve 220, a urea tank 230, a liquid level float 240, a urea filter 250, an exhaust valve 260, a urea line pressure sensor 270, and a urea nozzle 280. The onboard controller 104 is connected to the urea line pressure sensor 270.

[0067] The onboard controller 104 acquires urea line pressure data from the urea injection system during each injection cycle via the urea line pressure sensor 270 and transmits the acquired urea line pressure data to the computer device 106 via the network. The computer device 106 then obtains the maximum and minimum urea line pressures of the urea injection system during each effective cycle from the received urea line pressure data. Based on the maximum and minimum urea line pressures during each effective injection cycle, the computer device 106 determines the maximum pressure drop value during each effective injection cycle. The computer device 106 then compares the maximum pressure drop value during each effective injection cycle with a standard pressure drop value to determine the deviation corresponding to each effective injection cycle. Finally, the computer device 106 calculates the number of effective injection cycles characterized by these deviations, and performs urea injection system fault diagnosis based on the calculated number of cycles.

[0068] Computer device 106 may be a terminal or a server. Terminals may include, but are not limited to, various personal computers, laptops, smartphones, tablet computers, IoT devices, and portable wearable devices. IoT devices may include smart speakers, smart TVs, smart air conditioners, and smart car devices. Portable wearable devices may include smart watches, smart bracelets, and head-mounted devices. The server may be implemented as a standalone server or a server cluster consisting of multiple servers.

[0069] In one embodiment, Figure 3 As shown, a method for urea injection system fault diagnosis is provided. Figure 1 The computer device in the example is used to illustrate the process, including the following steps:

[0070] Step 302 : Acquire the maximum urea line pressure and the minimum urea line pressure of the urea injection system within the effective injection cycle.

[0071] The effective injection cycle is an injection cycle used to diagnose urea injection system failures.

[0072] Specifically, the onboard controller uses a urea line pressure sensor to acquire urea line pressure data from the urea injection system during each injection cycle and transmits this acquired urea line pressure data to a computer via a network. The computer then determines the maximum and minimum urea line pressures of the urea injection system during the effective injection cycle from this received urea line pressure data.

[0073] In one embodiment, the method for determining the effective injection cycle includes: monitoring the nozzle opening time of a preset number of consecutive injection cycles; if the nozzle opening time of the preset number of consecutive injection cycles is within a preset range, then determining that the preset number of consecutive injection cycles and the injection cycles after the preset number of consecutive injection cycles are effective injection cycles.

[0074] The nozzle open time is the period of time during each injection cycle that the nozzle is open to inject urea. The nozzle open time during each injection cycle is determined by the drive duty cycle and drive time during each injection cycle. During each injection cycle, the drive time is equal to the duration of the injection cycle.

[0075] Specifically, the on-board controller obtains the nozzle opening time of the urea injection system in each injection cycle and transmits the nozzle opening time of the urea injection system in each injection cycle to the computer device via a network. After obtaining the nozzle opening time of the urea injection system in each injection cycle, the computer device monitors the nozzle opening time of a preset number of consecutive injection cycles and determines whether the nozzle opening time of the preset number of consecutive injection cycles is within a preset range. If the nozzle opening time of the preset number of consecutive injection cycles is within the preset range, the computer device determines that the preset number of injection cycles and the injection cycles after the preset number of consecutive injection cycles are valid injection cycles.

[0076] It should be noted that the preset number of injection cycles can be three, two or four, and can be set specifically according to the accuracy of the diagnosis. This application does not impose any restrictions on this. The following further illustrates the method of determining the effective injection cycle when the preset number is three:

[0077] After obtaining the nozzle opening time of the urea injection system within each injection cycle, the computer device monitors the nozzle opening time of three consecutive injection cycles and determines whether the nozzle opening time of the three consecutive injection cycles is within a preset range. If the nozzle opening time of the three consecutive injection cycles is within the preset range, the third of the three consecutive injection cycles and the injection cycles thereafter are determined to be valid injection cycles. In other words, if the nozzle opening time of the first injection cycle is within the preset range, the nozzle opening time of the second injection cycle is within the preset range, and if the nozzle opening time of the third injection cycle is also within the preset range, then the third injection cycle is a valid injection cycle. The computer device then determines whether the nozzle opening time of the fourth injection cycle is within the preset range. If so, the fourth injection cycle is also a valid injection cycle. If not, the fourth injection cycle is not a valid injection cycle. Continue to monitor the fifth injection cycle, the sixth injection cycle and the seventh injection cycle. When the fourth injection cycle is not a valid injection cycle, if the nozzle opening time of the fifth injection cycle is within the preset range, and the nozzle opening time of the sixth injection cycle is within the preset range, if the nozzle opening time of the seventh injection cycle is also within the preset range, then the seventh injection cycle is a valid injection cycle.

[0078] In this embodiment, by monitoring the nozzle opening time of a preset number of injection cycles, if the nozzle opening time of the preset number of injection cycles is all within a preset range, the preset number of injection cycles and the injection cycles after the preset number of injection cycles are determined to be valid injection cycles, and then the urea injection system fault diagnosis is performed based on the valid injection cycles, which can improve the fault diagnosis efficiency of the urea injection system.

[0079] Step 304 : Obtaining a maximum pressure drop value in each effective injection cycle according to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle.

[0080] Specifically, after the computer device obtains the maximum urea line pressure and the minimum urea line pressure in each effective injection cycle, the maximum urea line pressure and the minimum urea line pressure in each effective injection cycle are subtracted according to formula (1) to obtain the maximum pressure drop value in each effective injection cycle.

[0081] p1=p max -p min (1)

[0082] Among them, p1 is the maximum pressure drop value in each effective injection cycle; p max The maximum urea pipeline pressure within each effective injection cycle; p minIt is the minimum urea line pressure within each effective injection cycle.

[0083] Step 306 : Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle.

[0084] The standard pressure drop value is the urea line pressure drop value when the urea injection system is in normal working condition. The deviation condition represents the deviation between the urea line pressure drop condition during an injection cycle and the urea line pressure drop condition when the urea injection system is in normal working condition.

[0085] Specifically, after the computer equipment calculates the maximum pressure drop value within each effective injection cycle, it also obtains the standard pressure drop value corresponding to each effective injection cycle, and then compares the maximum pressure drop value within each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle.

[0086] In one embodiment, the urea injection system fault diagnosis method further includes obtaining the nozzle opening time within each effective injection cycle; and querying a calibration chart based on the nozzle opening time to obtain a standard pressure drop value corresponding to each effective injection cycle.

[0087] The calibration chart is a pre-calibrated chart showing the relationship between the nozzle opening time and the standard pressure drop value.

[0088] Specifically, after the computer device calculates the maximum pressure drop value within each effective injection cycle, it also obtains the nozzle opening time of each effective injection cycle from the nozzle opening time within each injection cycle sent by the vehicle-mounted controller, and queries the calibration chart based on the nozzle opening time within each effective injection cycle, and obtains the standard pressure drop value corresponding to each effective injection cycle from the calibration chart.

[0089] In this embodiment, the nozzle opening time within each effective injection cycle is obtained, and a calibration chart is consulted based on the nozzle opening time to obtain the standard pressure drop value corresponding to each effective injection cycle. The pressure drop deviation within each effective injection cycle can then be determined using the standard pressure drop value, thereby enabling fault diagnosis of the urea injection system.

[0090] Step 308 : The statistical deviation situation characterizes the number of abnormal effective injection cycles, and a fault diagnosis of the urea injection system is performed based on the statistical number.

[0091] Specifically, after obtaining the deviation corresponding to each valid injection cycle, the computer device can determine the injection abnormality of the urea injection system in each valid injection cycle based on the deviation corresponding to each valid injection cycle. It should be noted that the injection abnormality of the urea injection system includes an abnormal urea line pressure drop that is too high and an abnormal urea line pressure drop that is too low. The computer device then counts the number of valid injection cycles characterized by the deviation, including the number of valid injection cycles with an abnormal urea line pressure drop that is too high and the number of valid injection cycles with an abnormal urea line pressure drop that is too low. Finally, based on the counted number of valid injection cycles with an abnormal urea line pressure drop that is too high and the number of valid injection cycles with an abnormal urea line pressure drop that is too low, a fault diagnosis of the urea injection system is performed.

[0092] In the above-mentioned urea injection system fault diagnosis method, the maximum urea line pressure and the minimum urea line pressure of the urea injection system within an effective injection cycle are obtained. Based on the maximum urea line pressure and the minimum urea line pressure within each effective injection cycle, the maximum pressure drop value within each effective injection cycle is obtained. The maximum pressure drop value within each effective injection cycle is then compared with a standard pressure drop value to obtain the deviation corresponding to each effective injection cycle. The deviation is used to determine whether the actual urea consumption caused by the urea injection system fault is too high or too low. Finally, the number of effective injection cycles characterized by abnormal deviations is counted, and the urea injection system fault diagnosis is performed based on the counted number of cycles. In this way, by determining the deviation within a certain number of effective cycles, the cause of the urea injection system fault can be determined, thereby improving the efficiency of urea injection system fault diagnosis.

[0093] In one embodiment, the above-mentioned urea injection system fault diagnosis method further includes: determining whether power-on initialization of the engine management system is completed; determining whether the urea solution and pipelines in the urea injection system are in an unfrozen state; determining whether the urea injection system is in an injection state; determining whether a urea line pressure sensor in the urea injection system is faulty; if power-on initialization of the engine management system is completed and continues for a preset time period, the urea solution and pipelines are in an unfrozen state within the preset time period, the urea injection system is in an injection state within the preset time period, and the urea line pressure sensor is not faulty within the preset time period, determining that a diagnosis enabling condition is satisfied; after the diagnosis enabling condition is satisfied, executing the step of obtaining a maximum urea line pressure and a minimum urea line pressure of the urea injection system within an effective injection cycle.

[0094] The diagnosis enabling condition represents a condition under which fault diagnosis of the urea injection system can be performed.

[0095] Specifically, before the computer device obtains the maximum and minimum urea line pressures of the urea injection system during an effective injection cycle, it is necessary to perform a diagnostic enable condition check on the urea injection system. When the diagnostic enable condition is met, it indicates that fault diagnosis of the urea injection system can begin. During the diagnostic enable condition check, the computer device obtains the operating status of the engine management system to determine whether power-on initialization of the engine management system has been completed; obtains the status of the urea solution and urea lines in the urea injection system to determine whether the urea solution and lines in the urea injection system are unfrozen; obtains the operating status of the urea injection system to determine whether the system is in an injection state; and obtains the operating status of a urea line pressure sensor installed in the urea injection system to determine whether the urea line pressure sensor in the urea injection system is faulty. In one embodiment, a worker may inspect the operating status of the engine management system, the status of the urea solution and urea lines in the urea injection system, the operating status of the urea injection system, and the operating status of a urea line pressure sensor in the urea injection system, and enter the inspection results into a computer device. The computer device can then obtain the operating status of the engine management system, the status of the urea solution and urea lines in the urea injection system, the operating status of the urea injection system, and the operating status of the urea line pressure sensor in the urea injection system. If the computer device determines that power-on initialization of the engine management system has been completed and maintained for a preset time period, that the urea solution and lines in the urea injection system have not frozen for a preset time period, that the urea injection system has been in an injection state for a preset time period, and that the urea line pressure sensor has not failed for a preset time period, then the diagnostic enabling condition is determined to be satisfied. The computer device can then begin the step of obtaining the maximum and minimum urea line pressures of the urea injection system during an effective injection cycle.

[0096] In this embodiment, the system determines whether power-on initialization of the engine management system is complete; determines whether the urea solution and pipelines in the urea injection system are unfrozen; determines whether the urea injection system is in an injection state; and determines whether a urea pipeline pressure sensor in the urea injection system is faulty. If power-on initialization of the engine management system is complete and continues for a preset time period, the urea solution and pipelines are unfrozen for the preset time period, the urea injection system is in an injection state for the preset time period, and the urea pipeline pressure sensor is fault-free for the preset time period, then the system determines that a diagnosis enabling condition is satisfied. If the diagnosis enabling condition is satisfied, the system executes the step of obtaining the maximum and minimum urea pipeline pressures of the urea injection system within an effective injection cycle. This ensures that fault diagnosis of the urea injection system proceeds smoothly, thereby improving the efficiency of fault diagnosis of the urea injection system.

[0097] In one embodiment, Figure 4As shown, the deviation condition includes a deviation value. The statistical deviation condition represents the number of abnormal effective injection cycles. The fault diagnosis of the urea injection system based on the statistical number includes:

[0098] Step 402: If the deviation value is greater than the first deviation threshold, the corresponding effective injection period is determined to be a first abnormal injection period.

[0099] The deviation value can be used to characterize the deviation. The first deviation threshold is a preset deviation threshold used to determine the presence of an abnormal urea line pressure drop. The first abnormal injection cycle is an injection cycle in which the urea line pressure drop is abnormally high.

[0100] Specifically, when the computer device compares the maximum pressure drop value within each effective injection cycle with the standard pressure drop value, the deviation value corresponding to each effective injection cycle can be obtained according to formula (2):

[0101]

[0102] Among them, p err is the deviation value corresponding to each effective injection cycle; p std It is the standard pressure drop value in each effective injection cycle.

[0103] Furthermore, after obtaining the deviation value corresponding to each effective injection cycle, the computer device compares the deviation value corresponding to each effective injection cycle with a preset deviation threshold. For one of the effective injection cycles, if the deviation value corresponding to the effective injection cycle is greater than the preset first deviation threshold, it indicates that the urea pipeline pressure drops abnormally too high in the urea injection system during the effective injection cycle, and the corresponding effective injection cycle can be determined as the first injection abnormality cycle.

[0104] Step 404 : If the deviation value is less than a second deviation threshold, determining the corresponding valid injection period as a second injection abnormality period; wherein the second deviation threshold is less than the first deviation threshold.

[0105] The second deviation threshold is a preset deviation threshold used to determine the presence of an abnormal urea line pressure drop. The second deviation threshold is smaller than the first deviation threshold. The second abnormal injection period is an injection period in which the abnormal urea line pressure drop is present.

[0106] Specifically, after the computer device obtains the deviation value corresponding to each effective injection cycle, the deviation value corresponding to each effective injection cycle is compared with a preset deviation threshold. For one of the effective injection cycles, if the deviation value corresponding to the effective injection cycle is less than a preset second deviation threshold, it indicates that the urea pipeline pressure drops too low in the urea injection system during the effective injection cycle. In this case, the corresponding effective injection cycle can be determined as a second injection abnormality cycle.

[0107] Step 406 , counting a first number of first injection abnormality cycles, and counting a second number of second injection abnormality cycles.

[0108] Specifically, the computer device determines whether each effective injection cycle belongs to the first injection abnormality cycle or the second injection abnormality cycle based on the deviation value of each effective injection cycle, and then counts the number of effective injection cycles determined to belong to the first injection abnormality cycle and the second injection abnormality cycle respectively. The number obtained by counting the effective injection cycles determined to belong to the first injection abnormality cycle is the first number, and the number obtained by counting the effective injection cycles determined to belong to the second injection abnormality cycle is the second number.

[0109] Step 408 : Calculate the high pressure drop abnormality rate based on the first number and the total number of valid injection cycle counts, and calculate the low pressure drop abnormality rate based on the second number and the total number of valid injection cycle counts.

[0110] Among them, the excessively high pressure drop abnormality rate represents the ratio of the number of effective injection cycles determined as the first injection abnormality cycle to the total number of effective injection cycle counts; the excessively low pressure drop abnormality rate represents the ratio of the number of effective injection cycles determined as the second injection abnormality cycle to the total number of effective injection cycle counts.

[0111] Specifically, after the computer device obtains a first number of first injection abnormality cycles and a second number of second injection abnormality cycles by counting, the first number and the total number of valid injection cycle counts are processed according to formula (3) to obtain the pressure drop abnormality rate, and the second number and the total number of valid injection cycle counts are processed according to formula (4) to obtain the pressure drop abnormality rate:

[0112]

[0113]

[0114] Among them, p ne1 is the abnormal rate of excessive pressure drop; n e1 is the first quantity; n total is the total number of effective injection cycle counts; p ne2 is the abnormal rate of low pressure drop; n e2The second quantity.

[0115] Step 410 : performing fault diagnosis on the urea injection system based on the abnormal rate of excessively high pressure drop and the abnormal rate of excessively low pressure drop.

[0116] Specifically, after the computer device calculates the excessively high pressure drop abnormality rate and the excessively low pressure drop abnormality rate, it compares the excessively high pressure drop abnormality rate and the excessively low pressure drop abnormality rate with a pre-set abnormality rate threshold. It should be noted that the pre-set abnormality rate threshold includes the excessively high pressure drop abnormality rate threshold and the excessively low pressure drop abnormality rate threshold. Therefore, the computer device compares the excessively high pressure drop abnormality rate with the pre-set excessively high pressure drop abnormality rate threshold, and compares the excessively low pressure drop abnormality rate with the pre-set excessively low pressure drop abnormality rate threshold. Finally, based on the comparison results between the excessively high pressure drop abnormality rate and the excessively low pressure drop abnormality rate and the pre-set abnormality rate threshold, the computer device performs fault diagnosis on the urea injection system.

[0117] In this embodiment, the deviation condition includes a deviation value. If the deviation value is greater than a first deviation threshold, the corresponding effective injection cycle is determined to be a first injection abnormality cycle. If the deviation value is less than a second deviation threshold, the corresponding effective injection cycle is determined to be a second injection abnormality cycle. The second deviation threshold is less than the first deviation threshold. A first number of the first injection abnormality cycles and a second number of the second injection abnormality cycles are counted. A high pressure drop abnormality rate is calculated based on the first number and the total number of effective injection cycles. A low pressure drop abnormality rate is calculated based on the second number and the total number of effective injection cycles. A urea injection system fault is then diagnosed based on the high and low pressure drop abnormality rates. In this manner, by counting the number of effective injection cycles with injection abnormalities, the high and low pressure drop abnormality rates are determined, respectively. Fault diagnosis of the urea injection system is then performed based on the high and low pressure drop abnormality rates. This not only allows the determination of the type of fault in the urea injection system, but also avoids bias caused by deviation in pressure change during a single detection, thereby improving the efficiency of urea injection system fault diagnosis.

[0118] In one embodiment, fault diagnosis of the urea injection system is performed based on the abnormal rate of excessively high pressure drop and the abnormal rate of excessively low pressure drop, including: if the abnormal rate of excessively low pressure drop exceeds a first abnormal threshold, determining that the urea nozzle of the urea injection system is clogged; if the abnormal rate of excessively high pressure drop exceeds a second abnormal threshold, obtaining a nitrogen oxide conversion rate; if the conversion rate is normal, determining that the urea nozzle is overspraying; if the conversion rate is less than the conversion rate threshold, determining that the urea filter is clogged.

[0119] The first abnormality threshold is a preset pressure drop too low abnormality rate threshold, and the second abnormality threshold is a preset pressure drop too high abnormality threshold.

[0120] Specifically, when the computer device compares the excessively high pressure drop abnormality rate and the excessively low pressure drop abnormality rate with a preset abnormality rate threshold, if the excessively low pressure drop abnormality rate exceeds the preset excessively low pressure drop abnormality rate threshold, the computer device can determine that the urea injection system has an excessively low pressure drop abnormality, thereby determining that the urea nozzle of the urea injection system is clogged. If the excessively high pressure drop abnormality rate exceeds the preset excessively high pressure drop abnormality rate threshold, the computer device can also determine that the urea injection system has an excessively high pressure drop abnormality. However, there may be multiple reasons for the excessively high pressure drop abnormality in the urea injection system. Therefore, when the computer device determines that the urea injection system has an excessively high pressure drop abnormality, it also obtains the nitrogen oxide conversion rate from the onboard controller. If the nitrogen oxide conversion rate is normal, the cause of the excessively high pressure drop abnormality in the urea injection system is urea nozzle overspray. If the nitrogen oxide conversion rate is less than the conversion rate threshold, the cause of the excessively high pressure drop abnormality in the urea injection system is a clogged urea filter.

[0121] In this embodiment, if the low pressure drop abnormality rate exceeds a first abnormality threshold, the urea nozzle of the urea injection system is determined to be clogged. If the high pressure drop abnormality rate exceeds a second abnormality threshold, the nitrogen oxide conversion rate is obtained. If the conversion rate is normal, the urea nozzle is determined to be overspraying. If the conversion rate is less than the conversion rate threshold, the urea filter is determined to be clogged. Thus, by combining the low pressure drop abnormality rate, the high pressure drop abnormality rate, and the nitrogen oxide conversion rate to perform fault diagnosis on the urea injection system, the cause of the urea injection system fault can be further determined, thereby improving the efficiency of urea injection system fault diagnosis.

[0122] The following is a detailed description of the urea injection system fault diagnosis method of the present application using a specific embodiment:

[0123] It should be noted that this embodiment is based on Figure 2 The urea injection system shown is used as the diagnosis object.

[0124] First, the computer equipment needs to determine whether the diagnostic enabling conditions are met. The diagnostic enabling conditions include: ① The engine management system is powered on and initialized; ② The urea solution and pipelines in the urea injection system are in an unfrozen state; ③ The urea injection system is in an injection state; ④ There are no faults in the urea pipeline pressure sensors.

[0125] When the above conditions are met at the same time and after a certain period of time of delay confirmation processing, the computer device can determine that the diagnosis enabling condition is met. Otherwise, the enabling condition is not met.

[0126] After determining that the diagnostic enabling conditions are met, the on-board controller controls the urea injection system to inject urea according to a fixed injection cycle, and the urea line pressure sensor starts to collect urea line pressure data of the urea injection system. The on-board controller then transmits the nozzle opening time of each injection cycle and the line pressure data collected by the urea line pressure sensor to the computer equipment.

[0127] The computer device determines whether the injection cycle is a valid injection cycle based on the nozzle opening time of each injection cycle. The valid injection cycle can be used to diagnose faults of the urea injection system. When the urea nozzle injects urea with a duration of 1s as one injection cycle, if the urea nozzle opening time t o If the nozzle opening time of three or more consecutive injection cycles is between the thresholds t1 and t2 and meets the requirements, the third and subsequent injection cycles are determined to be valid injection cycles. When a injection cycle is determined to be a valid injection cycle, the total number of valid injection cycles n is counted. total Add 1. From the urea line pressure data of the urea injection system corresponding to the effective injection cycle, obtain the maximum and minimum urea line pressures within the effective injection cycle. Furthermore, subtract the maximum and minimum urea line pressures within the effective injection cycle according to formula (1) to obtain the maximum pressure drop value within the effective injection cycle.

[0128] p1=p max -p min (5)

[0129] Among them, p1 is the maximum pressure drop value within an effective injection cycle; p max is the maximum urea pipeline pressure within an effective injection cycle; p min It is the minimum urea pipeline pressure within an effective injection cycle.

[0130] After determining the maximum pressure drop value within the effective injection cycle, the computer device also queries the calibration chart based on the nozzle opening time within the effective injection cycle to obtain the corresponding standard pressure drop value. The maximum pressure drop value within the effective injection cycle and the corresponding standard pressure drop value are then calculated according to formula (2) to obtain the deviation value corresponding to the effective injection cycle:

[0131]

[0132] Among them, p err is the deviation value corresponding to an effective injection cycle; p std It is the standard pressure drop value in the corresponding effective injection cycle.

[0133] like Figure 5As shown, if the calculated deviation value p err Greater than the first deviation threshold p up , then the first injection abnormality cycle count n e1 Add 1, and finally get the first number of the first injection abnormal period; if the deviation value is greater than p err Less than the second deviation threshold p down , then the second injection abnormality cycle count n e2 Add 1 and obtain the second number of the second injection abnormality period.

[0134] When the total number of valid injection cycles n total Reach the preset target value n diag When , stop counting, and calculate the abnormal rate of excessive pressure drop according to formula (7), and calculate the abnormal rate of excessive pressure drop according to formula (8):

[0135]

[0136]

[0137] Among them, p ne1 is the abnormal rate of excessive pressure drop; n e1 is the first quantity; n total is the total number of effective injection cycle counts; p ne2 is the abnormal rate of low pressure drop; n e2 The second quantity.

[0138] Finally, the computer equipment performs fault diagnosis of the urea injection system based on the abnormal rate of excessive pressure drop and the abnormal rate of excessive pressure drop: If the abnormal rate of excessive pressure drop p ne2 Exceeding the pressure drop too low abnormal rate threshold p e2 , indicating that the urea nozzle is blocked; if the pressure drops too high, the abnormal rate p ne1 Exceeding the pressure drop abnormal rate threshold p e1 It is also necessary to obtain the post-treatment nitrogen oxide conversion rate and further judge it in combination with the nitrogen oxide conversion rate. If the nitrogen oxide conversion rate is less than the conversion rate threshold, it means that the urea filter is blocked. If the nitrogen oxide conversion rate is normal, it means that the urea nozzle is overspraying.

[0139] In one embodiment, the urea injection system can be actively intervened, and the vehicle controller can be used to control the urea nozzle to spray for a period of time with a fixed nozzle opening time. When the injection condition reaches a stable state, the urea injection system is diagnosed.

[0140] In the above-mentioned urea injection system fault diagnosis method, the maximum urea line pressure and the minimum urea line pressure of the urea injection system within an effective injection cycle are obtained. Based on the maximum urea line pressure and the minimum urea line pressure within each effective injection cycle, the maximum pressure drop value within each effective injection cycle is obtained. The maximum pressure drop value within each effective injection cycle is then compared with a standard pressure drop value to obtain the deviation corresponding to each effective injection cycle. The deviation is used to determine whether the actual urea consumption caused by the urea injection system fault is too high or too low. Finally, the number of effective injection cycles characterized by the deviation is counted, and the urea injection system fault diagnosis is performed based on the counted number of cycles. In this way, by determining the deviation within a certain number of effective cycles, the cause of the urea injection system fault can be determined, thereby improving the efficiency of urea injection system fault diagnosis.

[0141] It should be understood that, although the various steps in the flowcharts involved in the various embodiments described above are displayed in sequence according to the instructions of the arrows, these steps are not necessarily executed in sequence in the order indicated by the arrows. Unless otherwise specified herein, there is no strict order restriction on the execution of these steps, and these steps can be executed in other orders. Moreover, at least a portion of the steps in the flowcharts involved in the various embodiments described above can include multiple steps or multiple stages, and these steps or stages are not necessarily executed and completed at the same time, but can be executed at different times, and the execution order of these steps or stages is not necessarily to be carried out in sequence, but can be executed in turn or alternately with other steps or at least a portion of steps or stages in other steps.

[0142] Based on the same inventive concept, in one embodiment, Figure 6 As shown, the embodiment of the present application further provides a urea injection system fault diagnosis device 600, comprising: an acquisition module 601, a calculation module 602, a comparison module 603 and a diagnosis module 604, wherein:

[0143] An acquisition module, used to acquire the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within an effective injection cycle;

[0144] a calculation module, configured to obtain a maximum pressure drop value within each effective injection cycle according to a maximum urea pipeline pressure and a minimum urea pipeline pressure within each effective injection cycle;

[0145] A comparison module is used to compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0146] The diagnosis module is used for statistically analyzing the number of effective injection cycles that are abnormal and performing fault diagnosis of the urea injection system based on the statistical number.

[0147] In one embodiment, the urea injection system fault diagnosis device further includes a determination module, configured to determine whether power-on initialization of the engine management system is completed; determine whether the urea solution and pipelines in the urea injection system are in an unfrozen state; determine whether the urea injection system is in an injection state; and determine whether a urea pipeline pressure sensor in the urea injection system is faulty. If power-on initialization of the engine management system is completed and continues for a preset time period, the urea solution and pipelines are in an unfrozen state within the preset time period, the urea injection system is in an injection state within the preset time period, and the urea pipeline pressure sensor is faulty within the preset time period, then it is determined that a diagnosis enabling condition is satisfied. After the diagnosis enabling condition is satisfied, the step of obtaining a maximum urea pipeline pressure and a minimum urea pipeline pressure of the urea injection system within an effective injection cycle is executed.

[0148] In one embodiment, the acquisition module is further used to: monitor the nozzle opening time of a preset number of consecutive injection cycles; if the nozzle opening time of a preset number of consecutive injection cycles is within a preset range, then determine that the preset number of consecutive injection cycles and the injection cycles after the preset number of consecutive injection cycles are valid injection cycles.

[0149] In one embodiment, the comparison module is further configured to: obtain the nozzle opening time within each effective injection cycle; and query a calibration chart according to the nozzle opening time to obtain a standard pressure drop value corresponding to each effective injection cycle.

[0150] In one embodiment, the deviation condition includes a deviation value, and the diagnostic module is further used to: if the deviation value is greater than a first deviation threshold, determine the corresponding effective injection cycle as a first injection abnormality cycle; if the deviation value is less than a second deviation threshold, determine the corresponding effective injection cycle as a second injection abnormality cycle; wherein the second deviation threshold is less than the first deviation threshold; count a first number of the first injection abnormality cycles, and count a second number of the second injection abnormality cycles; calculate a high pressure drop abnormality rate based on the first number and the total number of effective injection cycle counts, and calculate a low pressure drop abnormality rate based on the second number and the total number of effective injection cycle counts; and perform fault diagnosis of the urea injection system based on the high pressure drop abnormality rate and the low pressure drop abnormality rate.

[0151] In one embodiment, the diagnostic module is further configured to: determine that the urea nozzle of the urea injection system is clogged if the pressure drop abnormality rate exceeds a first abnormality threshold; obtain a nitrogen oxide conversion rate if the pressure drop abnormality rate exceeds a second abnormality threshold, determine that the urea nozzle is overspraying if the conversion rate is normal, and determine that the urea filter is clogged if the conversion rate is less than the conversion rate threshold.

[0152] Each module in the urea injection system fault diagnosis device can be implemented in whole or in part through software, hardware, or a combination thereof. Each module can be embedded in or independent of a processor in a computer device in the form of hardware, or can be stored in a memory in the computer device in the form of software, so that the processor can call and execute the corresponding operations of each module.

[0153] In one embodiment, a computer device is provided. The computer device may be a terminal, and its internal structure diagram may be as follows: Figure 7 As shown. The computer device includes a processor, a memory, an input / output interface, a communication interface, a display unit and an input device. The processor, the memory and the input / output interface are connected via a system bus, and the communication interface, the display unit and the input device are connected to the system bus via the input / output interface. The processor of the computer device is used to provide computing and control capabilities. The memory of the computer device includes a non-volatile storage medium and an internal memory. The non-volatile storage medium stores an operating system and a computer program. The internal memory provides an environment for the operation of the operating system and the computer program in the non-volatile storage medium. The input / output interface of the computer device is used to exchange information between the processor and an external device. The communication interface of the computer device is used to communicate with an external terminal in a wired or wireless manner, and the wireless manner can be achieved through WIFI, a mobile cellular network, NFC (near field communication) or other technologies. When the computer program is executed by the processor, a method for diagnosing faults in a urea injection system is implemented. The display unit of the computer device is used to form a visually visible image, which can be a display screen, a projection device or a virtual reality imaging device. The display screen can be a liquid crystal display screen or an electronic ink display screen, and the input device of the computer device can be a touch layer covering the display screen, or a button, trackball or touchpad set on the computer device casing, or an external keyboard, touchpad or mouse.

[0154] Those skilled in the art will understand that Figure 7 The structure shown in the figure is only a block diagram of a part of the structure related to the solution of the present application, and does not constitute a limitation on the computer device to which the solution of the present application is applied. The specific computer device may include more or fewer components than shown in the figure, or combine certain components, or have a different component arrangement.

[0155] In one embodiment, a computer device is provided, including a memory and a processor, wherein a computer program is stored in the memory, and when the processor executes the computer program, the following steps are implemented:

[0156] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0157] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0158] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0159] The statistical deviation situation represents the number of abnormal effective injection cycles, and the fault diagnosis of the urea injection system is performed based on the statistical number.

[0160] In one embodiment, when executing the computer program, the processor further implements the following steps: determining whether power-on initialization of the engine management system is completed; determining whether the urea solution and the pipeline in the urea injection system are in an unfrozen state; determining whether the urea injection system is in an injection state; and determining whether a urea pipeline pressure sensor in the urea injection system is faulty; if power-on initialization of the engine management system is completed and continues for a preset time period, the urea solution and the pipeline are in an unfrozen state within the preset time period, the urea injection system is in an injection state within the preset time period, and the urea pipeline pressure sensor is faulty within the preset time period, determining that a diagnosis enabling condition is satisfied; and after the diagnosis enabling condition is satisfied, executing the step of obtaining a maximum urea pipeline pressure and a minimum urea pipeline pressure of the urea injection system within an effective injection cycle.

[0161] In one embodiment, when the processor executes the computer program, it also implements the following steps: monitoring the nozzle opening time of a preset number of consecutive injection cycles; if the nozzle opening time of a preset number of consecutive injection cycles is all within a preset range, determining that the preset number of consecutive injection cycles and the injection cycles after the preset number of consecutive injection cycles are valid injection cycles.

[0162] In one embodiment, when the processor executes the computer program, the following steps are further implemented: obtaining the nozzle opening time in each effective injection cycle; querying the calibration chart according to the nozzle opening time to obtain the standard pressure drop value corresponding to each effective injection cycle.

[0163] In one embodiment, the deviation condition includes a deviation value, and the processor further implements the following steps when executing the computer program: if the deviation value is greater than a first deviation threshold, determining the corresponding effective injection cycle as a first injection abnormality cycle; if the deviation value is less than a second deviation threshold, determining the corresponding effective injection cycle as a second injection abnormality cycle; wherein the second deviation threshold is less than the first deviation threshold; counting a first number of the first injection abnormality cycles, and counting a second number of the second injection abnormality cycles; calculating a high pressure drop abnormality rate based on the first number and the total number of effective injection cycle counts, and calculating a low pressure drop abnormality rate based on the second number and the total number of effective injection cycle counts; and performing fault diagnosis of the urea injection system based on the high pressure drop abnormality rate and the low pressure drop abnormality rate.

[0164] In one embodiment, when the processor executes the computer program, the following steps are further implemented: if the pressure drop abnormal rate exceeds a first abnormal threshold, it is determined that the urea nozzle of the urea injection system is clogged; if the pressure drop abnormal rate exceeds a second abnormal threshold, the nitrogen oxide conversion rate is obtained, and if the conversion rate is normal, it is determined that the urea nozzle is overspraying; if the conversion rate is less than the conversion rate threshold, it is determined that the urea filter is clogged.

[0165] In one embodiment, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the following steps are implemented:

[0166] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0167] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0168] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0169] The statistical deviation situation represents the number of abnormal effective injection cycles, and the fault diagnosis of the urea injection system is performed based on the statistical number.

[0170] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: determining whether power-on initialization of the engine management system is completed; determining whether the urea solution and the pipeline in the urea injection system are in an unfrozen state; determining whether the urea injection system is in an injection state; and determining whether a urea pipeline pressure sensor in the urea injection system is faulty; if power-on initialization of the engine management system is completed and continues for a preset time period, the urea solution and the pipeline are in an unfrozen state within the preset time period, the urea injection system is in an injection state within the preset time period, and the urea pipeline pressure sensor is faulty within the preset time period, determining that a diagnosis enabling condition is satisfied; and after the diagnosis enabling condition is satisfied, executing the step of obtaining a maximum urea pipeline pressure and a minimum urea pipeline pressure of the urea injection system within an effective injection cycle.

[0171] In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: monitoring the nozzle opening time of a preset number of consecutive injection cycles; if the nozzle opening time of a preset number of consecutive injection cycles is all within a preset range, determining that the preset number of consecutive injection cycles and the injection cycles after the preset number of consecutive injection cycles are valid injection cycles.

[0172] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: obtaining the nozzle opening time in each effective injection cycle; querying the calibration chart according to the nozzle opening time to obtain the standard pressure drop value corresponding to each effective injection cycle.

[0173] In one embodiment, the deviation condition includes a deviation value, and the computer program, when executed by the processor, further implements the following steps: if the deviation value is greater than a first deviation threshold, determining the corresponding effective injection cycle as a first injection abnormality cycle; if the deviation value is less than a second deviation threshold, determining the corresponding effective injection cycle as a second injection abnormality cycle; wherein the second deviation threshold is less than the first deviation threshold; counting a first number of the first injection abnormality cycles, and counting a second number of the second injection abnormality cycles; calculating a high pressure drop abnormality rate based on the first number and the total number of effective injection cycle counts, and calculating a low pressure drop abnormality rate based on the second number and the total number of effective injection cycle counts; and performing fault diagnosis of the urea injection system based on the high pressure drop abnormality rate and the low pressure drop abnormality rate.

[0174] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: if the pressure drop abnormal rate exceeds a first abnormal threshold, it is determined that the urea nozzle of the urea injection system is clogged; if the pressure drop abnormal rate exceeds a second abnormal threshold, the nitrogen oxide conversion rate is obtained, and if the conversion rate is normal, it is determined that the urea nozzle is overspraying; if the conversion rate is less than the conversion rate threshold, it is determined that the urea filter is clogged.

[0175] In one embodiment, a computer program product is provided, comprising a computer program, which, when executed by a processor, implements the following steps:

[0176] Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle;

[0177] According to the maximum urea pipeline pressure and the minimum urea pipeline pressure in each effective injection cycle, the maximum pressure drop value in each effective injection cycle is obtained;

[0178] Compare the maximum pressure drop value in each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle;

[0179] The statistical deviation situation represents the number of abnormal effective injection cycles, and the fault diagnosis of the urea injection system is performed based on the statistical number.

[0180] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: determining whether power-on initialization of the engine management system is completed; determining whether the urea solution and the pipeline in the urea injection system are in an unfrozen state; determining whether the urea injection system is in an injection state; and determining whether a urea pipeline pressure sensor in the urea injection system is faulty; if power-on initialization of the engine management system is completed and continues for a preset time period, the urea solution and the pipeline are in an unfrozen state within the preset time period, the urea injection system is in an injection state within the preset time period, and the urea pipeline pressure sensor is faulty within the preset time period, determining that a diagnosis enabling condition is satisfied; and after the diagnosis enabling condition is satisfied, executing the step of obtaining a maximum urea pipeline pressure and a minimum urea pipeline pressure of the urea injection system within an effective injection cycle.

[0181] In one embodiment, when the computer program is executed by the processor, the following steps are also implemented: monitoring the nozzle opening time of a preset number of consecutive injection cycles; if the nozzle opening time of a preset number of consecutive injection cycles is all within a preset range, determining that the preset number of consecutive injection cycles and the injection cycles after the preset number of consecutive injection cycles are valid injection cycles.

[0182] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: obtaining the nozzle opening time in each effective injection cycle; querying the calibration chart according to the nozzle opening time to obtain the standard pressure drop value corresponding to each effective injection cycle.

[0183] In one embodiment, the deviation condition includes a deviation value, and the computer program, when executed by the processor, further implements the following steps: if the deviation value is greater than a first deviation threshold, determining the corresponding effective injection cycle as a first injection abnormality cycle; if the deviation value is less than a second deviation threshold, determining the corresponding effective injection cycle as a second injection abnormality cycle; wherein the second deviation threshold is less than the first deviation threshold; counting a first number of the first injection abnormality cycles, and counting a second number of the second injection abnormality cycles; calculating a high pressure drop abnormality rate based on the first number and the total number of effective injection cycle counts, and calculating a low pressure drop abnormality rate based on the second number and the total number of effective injection cycle counts; and performing fault diagnosis of the urea injection system based on the high pressure drop abnormality rate and the low pressure drop abnormality rate.

[0184] In one embodiment, when the computer program is executed by the processor, the following steps are further implemented: if the pressure drop abnormal rate exceeds a first abnormal threshold, it is determined that the urea nozzle of the urea injection system is clogged; if the pressure drop abnormal rate exceeds a second abnormal threshold, the nitrogen oxide conversion rate is obtained, and if the conversion rate is normal, it is determined that the urea nozzle is overspraying; if the conversion rate is less than the conversion rate threshold, it is determined that the urea filter is clogged.

[0185] Those skilled in the art will appreciate that all or part of the processes in the above-mentioned embodiment methods can be implemented by instructing the relevant hardware through a computer program, and the computer program can be stored in a non-volatile computer-readable storage medium. When the computer program is executed, it can include the processes of the embodiments of the above-mentioned methods. Among them, any reference to memory, database or other media used in the embodiments provided in this application may include at least one of non-volatile and volatile memory. Non-volatile memory may include read-only memory (ROM), magnetic tape, floppy disk, flash memory, optical memory, high-density embedded non-volatile memory, resistive random access memory (ReRAM), magnetic random access memory (MRAM), ferroelectric random access memory (FRAM), phase change memory (PCM), graphene memory, etc. Volatile memory may include random access memory (RAM) or external cache memory, etc. By way of illustration and not limitation, RAM can be in various forms, such as static random access memory (SRAM) or dynamic random access memory (DRAM). The database involved in the various embodiments provided herein may include at least one of a relational database and a non-relational database. Non-relational databases may include, but are not limited to, distributed databases based on blockchains. The processor involved in the various embodiments provided herein may be, but are not limited to, a general-purpose processor, a central processing unit, a graphics processing unit, a digital signal processor, a programmable logic unit, a data processing logic unit based on quantum computing, and the like.

[0186] The technical features of the above embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0187] The above-described embodiments merely represent several implementation methods of the present application. While the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the present application. It should be noted that a person of ordinary skill in the art may make various modifications and improvements without departing from the spirit of the present application, and these modifications and improvements fall within the scope of protection of the present application. Therefore, the scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for diagnosing a urea injection system fault, characterized in that: The method comprises: Obtain the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within the effective injection cycle; Obtaining a maximum pressure drop value within each effective injection cycle according to a maximum urea line pressure and a minimum urea line pressure within each effective injection cycle; wherein obtaining the maximum pressure drop value within each effective injection cycle according to the maximum urea line pressure and the minimum urea line pressure within each effective injection cycle comprises: subtracting the maximum urea line pressure and the minimum urea line pressure within each effective injection cycle to obtain the maximum pressure drop value within each effective injection cycle; Obtaining the nozzle opening time within each effective injection cycle, querying a calibration chart based on the nozzle opening time, and obtaining a standard pressure drop value corresponding to each effective injection cycle; Comparing the maximum pressure drop value within each effective injection cycle with the standard pressure drop value to obtain a deviation corresponding to each effective injection cycle; wherein the deviation includes a deviation value, and comparing the maximum pressure drop value within each effective injection cycle with the standard pressure drop value to obtain the deviation corresponding to each effective injection cycle includes: subtracting the maximum pressure drop value from the corresponding standard pressure drop value to obtain a difference, and the ratio of the difference to the corresponding standard pressure drop value is the deviation value; The statistical deviation condition represents the number of abnormal effective injection cycles, and a fault diagnosis of the urea injection system is performed based on the number. The statistical deviation condition represents the number of abnormal effective injection cycles, and a fault diagnosis of the urea injection system is performed based on the number, including: If the deviation value is greater than the first deviation threshold, determining the corresponding effective injection period as the first injection abnormality period; If the deviation value is less than a second deviation threshold, determining the corresponding effective injection period as a second injection abnormality period; wherein the second deviation threshold is less than the first deviation threshold; Counting a first number of first injection abnormality cycles, and counting a second number of second injection abnormality cycles; Calculating a high pressure drop abnormality rate based on the first number and the total number of valid injection cycle counts, and calculating a low pressure drop abnormality rate based on the second number and the total number of valid injection cycle counts; A fault diagnosis of the urea injection system is performed based on the excessively high pressure drop abnormal rate and the excessively low pressure drop abnormal rate.

2. The method according to claim 1, characterized in that The method further comprises: Determine whether the power-on initialization of the engine management system is completed; determining whether the urea solution and pipelines in the urea injection system are in an unfrozen state; determining whether the urea injection system is in an injection state; determining whether a urea line pressure sensor in the urea injection system is faulty; If the power-on initialization of the engine management system is completed and continues for a preset time, the urea solution and the pipeline are in an unfrozen state within the preset time, the urea injection system is in an injection state within the preset time, and the urea pipeline pressure sensor has no fault within the preset time, then it is determined that the diagnosis enabling condition is met; After the diagnosis enabling condition is met, the step of obtaining the maximum urea line pressure and the minimum urea line pressure of the urea injection system within the effective injection cycle is performed.

3. The method according to claim 1, characterized in that The effective injection period is determined by: Monitoring the nozzle opening time for a preset number of consecutive spray cycles; If the nozzle opening time of the continuous preset number of injection cycles is within the preset range, the preset number of injection cycles and the injection cycles after the preset number of injection cycles are determined to be valid injection cycles.

4. The method according to claim 1, wherein The fault diagnosis of the urea injection system according to the abnormal rate of excessively high pressure drop and the abnormal rate of excessively low pressure drop includes: If the pressure drop abnormal rate exceeds a first abnormal threshold, it is determined that the urea nozzle of the urea injection system is clogged; If the pressure drop abnormal rate exceeds a second abnormal threshold, the nitrogen oxide conversion rate is obtained. If the conversion rate is normal, it is determined that the urea nozzle is overspraying. If the conversion rate is less than the conversion rate threshold, it is determined that the urea filter is clogged.

5. A urea injection system fault diagnosis device, characterized in that: The device comprises: An acquisition module, used to acquire the maximum urea pipeline pressure and the minimum urea pipeline pressure of the urea injection system within an effective injection cycle; a calculation module, configured to obtain a maximum pressure drop value within each effective injection cycle based on a maximum urea line pressure and a minimum urea line pressure within each effective injection cycle; and further configured to obtain a maximum pressure drop value within each effective injection cycle by subtracting the maximum urea line pressure from the minimum urea line pressure within each effective injection cycle; a comparison module, configured to compare the maximum pressure drop value within each effective injection cycle with the standard pressure drop value to obtain a deviation corresponding to each effective injection cycle; the comparison module is further configured to obtain the nozzle opening time within each effective injection cycle; and query a calibration chart based on the nozzle opening time to obtain a standard pressure drop value corresponding to each effective injection cycle; the deviation includes a deviation value, and the comparison module is further configured to subtract the maximum pressure drop value from the corresponding standard pressure drop value to obtain a difference value, wherein the ratio of the difference to the corresponding standard pressure drop value is the deviation value; a diagnostic module configured to count a number of effective injection cycles in which the deviation indicates an abnormality, and perform fault diagnosis of the urea injection system based on the number; the diagnostic module further configured to determine that the corresponding effective injection cycle is a first abnormal injection cycle if the deviation value is greater than a first deviation threshold; If the deviation value is less than a second deviation threshold, determining the corresponding effective injection period as a second injection abnormality period; wherein the second deviation threshold is less than the first deviation threshold; Counting a first number of first injection abnormality cycles, and counting a second number of second injection abnormality cycles; Calculating a high pressure drop abnormality rate based on the first number and the total number of valid injection cycle counts, and calculating a low pressure drop abnormality rate based on the second number and the total number of valid injection cycle counts; A fault diagnosis of the urea injection system is performed based on the excessively high pressure drop abnormal rate and the excessively low pressure drop abnormal rate.

6. A computer device comprising a memory and a processor, wherein the memory stores a computer program, wherein: When the processor executes the computer program, the steps of the method according to any one of claims 1 to 4 are implemented.

7. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

8. A computer program product comprising a computer program, characterized in that When the computer program is executed by a processor, the steps of the method according to any one of claims 1 to 4 are implemented.

Images