Intelligent maintenance method and device for urea filter screen

Abstract

The application relates to a urea filter screen intelligent maintenance method and device, and relates to the technical field of urea filter screens.The method comprises the following steps: obtaining a window time corresponding to a clogging evaluation coefficient cumulative value reaching a clogging evaluation coefficient threshold value; obtaining a difference value between a maximum value and a minimum value of the window time in a first preset comparison period; obtaining a first window time comparison difference value of all working condition points from a current working condition point to a second preset comparison period away from the current working condition point; determining whether the first window time comparison difference value changes by more than a first set threshold value; if the fluctuation difference value of the first window time comparison difference value in the second preset comparison period is greater than a first difference threshold value and smaller than a second difference threshold value, the first difference statistical frequency is increased by 1; if the first difference statistical frequency in a third preset judgment period is greater than a preset first statistical frequency threshold value, a urea filter screen clogging early warning is issued. The application can determine whether the urea filter screen is clogged through logical judgment based on vehicle self-provided information, and can perform maintenance reminding, so that the vehicle driving is not affected.

Description

Technical Field

[0001] This application relates to the field of urea filter technology, specifically to an intelligent maintenance method and device for urea filters. Background Technology

[0002] Currently, diesel engine manufacturers are developing China VI diesel engines, which aim to reduce NOx emissions in engine exhaust. x All are equipped with the Urea_SCR system, which injects urea into the exhaust pipe through a urea injection system, where the urea decomposes into NH3, which then reacts with NO. x Reactions to reduce NO x emission.

[0003] The urea pump is a precision component. If there are impurities in the urea solution, the flow of the solution through the pump can damage it. Therefore, a urea filter is added to the urea tank to filter the urea solution and ensure that the pump is not damaged. Over time, the urea filter will accumulate more impurities, eventually becoming clogged. Clogged filters prevent the urea solution from flowing properly, causing the urea injection system to malfunction. This leads to increased vehicle emissions, exceeding emission standards and triggering torque and speed limits, affecting vehicle performance.

[0004] Therefore, to address the aforementioned technical issues and meet maintenance needs, we now offer intelligent maintenance technology for urea filters. Summary of the Invention

[0005] This application provides a method and device for intelligent maintenance of urea filters. The method uses information from the vehicle to make a logical judgment on whether the urea filter is clogged, and then provides a urea filter maintenance reminder to avoid affecting vehicle operation.

[0006] To achieve the above objectives, this application provides the following solution.

[0007] In a first aspect, this application provides a method for intelligent maintenance of urea filters, the method comprising the following steps:

[0008] Based on the working conditions of the urea filter and urea pump, the cumulative value of the blockage evaluation coefficient at the current working point is calculated, and the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold is obtained, which is recorded as the first preset comparison period.

[0009] The difference between the maximum and minimum values ​​of the window time within the first preset comparison period is obtained and recorded as the first window time comparison difference of the current working condition point.

[0010] Get the first window time comparison difference between the current working point and all working points from the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first preset threshold.

[0011] If the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the first difference threshold and less than the second difference threshold, then the first difference count is incremented by 1.

[0012] If, within the third preset judgment period, the number of times the first difference is counted exceeds a preset first count threshold, a urea filter blockage warning will be issued; wherein...

[0013] The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period.

[0014] The default value for the first difference count is 0.

[0015] Furthermore, the method also includes the following steps:

[0016] If the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the second difference threshold, then the second difference count is incremented by 1;

[0017] If, within the third preset judgment period, the number of times the second difference is counted exceeds a preset second count threshold, a urea pump fault warning is issued; wherein...

[0018] The default value for the second difference count is 0.

[0019] Furthermore, based on the operating conditions of the urea filter and urea pump, the cumulative value of the blockage evaluation coefficient at preset operating points is calculated, and the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold is obtained, including the following steps:

[0020] Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, calculate the cumulative value of the blockage evaluation coefficient for the preset working conditions.

[0021] Obtain the window time corresponding to when the accumulated value of the congestion evaluation coefficient reaches the congestion evaluation coefficient threshold.

[0022] Furthermore, based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, the cumulative value of the blockage evaluation coefficient for preset operating points is calculated, including the following steps:

[0023] Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, the blockage evaluation coefficient of the preset working point is continuously calculated and continuously summed, and recorded as the blockage evaluation coefficient value sum.

[0024] If the sum of the congestion evaluation coefficient values ​​is greater than the preset congestion evaluation coefficient setting value, then the corresponding sum of the congestion evaluation coefficient values ​​will be used as the cumulative value of the congestion evaluation coefficient.

[0025] Furthermore, the method also includes the following steps:

[0026] If the sum of the blockage evaluation coefficient values ​​is greater than the preset blockage evaluation coefficient setting value, then the calculation of the blockage evaluation coefficient for the preset working condition point will be terminated.

[0027] Furthermore, the method calculates the blockage evaluation coefficient of the operating point based on a preset blockage evaluation coefficient formula;

[0028] The formula for the blockage evaluation coefficient is: in,

[0029] UF is the blockage evaluation coefficient, Pa is the actual urea injection pressure, P is the urea injection target pressure, V1 is the urea injection quantity, V is the urea injection target volume, and Δt is the urea injection time interval.

[0030] Furthermore, the preset first statistical count threshold is 1000;

[0031] The first difference threshold is 10;

[0032] The second difference threshold is 50;

[0033] The second preset judgment period is 10 to 1000 seconds;

[0034] The third preset judgment period is 1 hour.

[0035] Secondly, this application provides a smart maintenance device for urea filters, the device comprising:

[0036] The window time recording module is used to calculate the cumulative value of the blockage evaluation coefficient at the current working point based on the working status of the urea filter and the urea pump, and to obtain the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold, which is recorded as the first preset comparison period.

[0037] The window time comparison module is used to obtain the difference between the maximum and minimum values ​​of the window time within a preset comparison period, which is denoted as the window time comparison difference.

[0038] The first difference statistics module is used to obtain the difference between the maximum and minimum values ​​of the window time within the first preset comparison period, and record it as the first window time comparison difference of the current working condition point.

[0039] The first determination module is used to obtain the first window time comparison difference between the current working point and all working points from the current working point to the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first set threshold.

[0040] The first recording module is used to increment the first difference count by 1 if the fluctuation difference of the first window time comparison difference in the second preset comparison period is greater than the first difference threshold and less than the second difference threshold.

[0041] The first early warning module is used to issue a urea filter blockage warning if, within a third preset judgment period, the number of times the first difference is counted exceeds a preset first count threshold; wherein...

[0042] The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period.

[0043] The default value for the first difference count is 0.

[0044] Furthermore, the device also includes:

[0045] The second recording module is used to increment the second difference count by 1 if the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the second difference threshold.

[0046] The second early warning module is used to issue a urea pump fault warning if the number of statistical counts of the second difference exceeds a preset second statistical count threshold within the third preset judgment period; wherein...

[0047] The default value for the second difference count is 0.

[0048] Furthermore, the window time recording module is also used to calculate the cumulative value of the blockage evaluation coefficient for the preset working point based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume.

[0049] The window time recording module is also used to obtain the window time corresponding to when the cumulative value of the congestion evaluation coefficient reaches the congestion evaluation coefficient threshold.

[0050] Furthermore, the window time recording module is also used to continuously calculate the blockage evaluation coefficient of the preset working condition point based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, and continuously sum them up, which is recorded as the blockage evaluation coefficient value sum.

[0051] The window time recording module is also used to use the sum of the congestion evaluation coefficients as the cumulative value of the congestion evaluation coefficients if the sum of the congestion evaluation coefficients is greater than the preset congestion evaluation coefficient setting value.

[0052] Furthermore, the device also includes a first termination module, which is used to terminate the calculation of the blockage evaluation coefficient of the preset working condition point if the sum of the blockage evaluation coefficient values ​​is greater than the preset blockage evaluation coefficient setting value.

[0053] Furthermore, the device is equipped with a preset blockage evaluation coefficient formula;

[0054] The formula for the blockage evaluation coefficient is: in,

[0055] UF is the blockage evaluation coefficient, Pa is the actual urea injection pressure, P is the urea injection target pressure, V1 is the urea injection quantity, V is the urea injection target volume, and Δt is the urea injection time interval.

[0056] Furthermore, the preset first statistical count threshold is 1000;

[0057] The first difference threshold is 10;

[0058] The second difference threshold is 50;

[0059] The second preset judgment period is 10 to 1000 seconds;

[0060] The third preset judgment period is 1 hour.

[0061] The beneficial effects of the technical solution provided in this application include:

[0062] This application uses the vehicle's built-in information to logically determine whether the urea filter is clogged, and then provides a urea filter maintenance reminder to avoid affecting vehicle operation. Attached Figure Description

[0063] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0064] Figure 1 This is a flowchart illustrating the steps of the intelligent maintenance method for urea filters provided in the embodiments of this application.

[0065] Figure 2 This is a schematic diagram of the window time curve in the intelligent maintenance method for urea filters provided in the embodiments of this application;

[0066] Figure 3 This is a urea filter clogging curve diagram in the intelligent urea filter maintenance method provided in this application embodiment;

[0067] Figure 4 This is a fault curve diagram of the urea pump in the intelligent maintenance method for urea filters provided in the embodiments of this application;

[0068] Figure 5 This is a structural block diagram of the intelligent urea filter maintenance device provided in the embodiments of this application. Detailed Implementation

[0069] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0070] The embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0071] This application provides a method and device for intelligent maintenance of urea filters. The method uses information from the vehicle to logically determine whether the urea filter is clogged, and then provides a urea filter maintenance reminder to avoid affecting vehicle operation.

[0072] To achieve the aforementioned technical effects, the overall concept of this application is as follows:

[0073] A smart maintenance method for urea filters, comprising the following steps:

[0074] S1. Based on the working conditions of the urea filter and urea pump, calculate the cumulative value of the blockage evaluation coefficient at the current working point, and obtain the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold, which is recorded as the first preset comparison period.

[0075] S2. Obtain the difference between the maximum and minimum values ​​of the window time within the first preset comparison period, and record it as the first window time comparison difference of the current working condition point.

[0076] S3. Obtain the first window time comparison difference between the current working point and all working points in the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first preset threshold.

[0077] S4. If the fluctuation difference of the first window time comparison difference in the second preset comparison period is greater than the first difference threshold and less than the second difference threshold, then the first difference count is incremented by 1.

[0078] S5. If, within the third preset judgment period, the number of times the first difference is counted exceeds the preset first count threshold, a urea filter blockage warning is issued; whereby...

[0079] The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period.

[0080] The default value for the first difference count is 0.

[0081] The embodiments of this application will be further described in detail below with reference to the accompanying drawings.

[0082] Firstly, see [the following] Figures 1-4 As shown in the figure, this application provides a method for intelligent maintenance of urea filters, which includes the following steps:

[0083] S1. Based on the working conditions of the urea filter and urea pump, calculate the cumulative value of the blockage evaluation coefficient at the current working point, and obtain the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold, which is recorded as the first preset comparison period.

[0084] S2. Obtain the difference between the maximum and minimum values ​​of the window time within the first preset comparison period, and record it as the first window time comparison difference of the current working condition point.

[0085] S3. Obtain the first window time comparison difference between the current working point and all working points in the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first preset threshold.

[0086] S4. If the fluctuation difference of the first window time comparison difference in the second preset comparison period is greater than the first difference threshold and less than the second difference threshold, then the first difference count is incremented by 1.

[0087] S5. If, within the third preset judgment period, the number of times the first difference is counted exceeds the preset first count threshold, a urea filter blockage warning is issued; whereby...

[0088] The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period.

[0089] The default value for the first difference count is 0.

[0090] It should be noted that the existing technical solution involves periodically maintaining the urea filter by removing and replacing it. The maintenance mileage is related to the size of the urea filter, and the current industry standard is 100,000 kilometers or 1 year. The technical problems with the existing technology are as follows:

[0091] 1) Poor adaptability: Currently, urea filter maintenance is performed according to fixed time or fixed mileage, which is not adaptable;

[0092] If the urea used in the vehicle is of poor quality, it will shorten the maintenance interval, and the vehicle will experience filter clogging problems in advance, which will lead to excessive vehicle emissions, limited torque and speed, and affect vehicle operation.

[0093] If the vehicle uses high-quality urea, the maintenance interval can be extended, reducing vehicle maintenance costs.

[0094] 2) Insufficient predictability: Commercial vehicles operate over a wide area, and there may not be service stations in the areas where the vehicles operate. Clogged urea filters can cause the vehicle to be limited in torque and speed, affecting vehicle operation. If urea filter clogging can be predicted in advance, the vehicle can be replaced in advance, thereby avoiding the impact on the vehicle.

[0095] This application embodiment mainly diagnoses urea filter blockage by diagnosing the difference between the actual pressure and the target pressure of urea injection.

[0096] This technical solution does not require the installation of new sensors or special equipment. It uses information from the vehicle itself to logically determine whether the urea filter is clogged and reminds the driver in advance to go to the service station to maintain the urea filter, thereby avoiding affecting the vehicle's operation.

[0097] Furthermore, the method also includes the following steps:

[0098] If the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the second difference threshold, then the second difference count is incremented by 1;

[0099] If, within the third preset judgment period, the number of times the second difference is counted exceeds a preset second count threshold, a urea pump fault warning is issued; wherein...

[0100] The default value for the second difference count is 0.

[0101] Furthermore, based on the operating conditions of the urea filter and urea pump, the cumulative value of the blockage evaluation coefficient at preset operating points is calculated, and the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold is obtained, including the following steps:

[0102] Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, calculate the cumulative value of the blockage evaluation coefficient for the preset working conditions.

[0103] Obtain the window time corresponding to when the accumulated value of the congestion evaluation coefficient reaches the congestion evaluation coefficient threshold.

[0104] Furthermore, based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, the cumulative value of the blockage evaluation coefficient for preset operating points is calculated, including the following steps:

[0105] Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, the blockage evaluation coefficient of the preset working point is continuously calculated and continuously summed, and recorded as the blockage evaluation coefficient value sum.

[0106] If the sum of the congestion evaluation coefficient values ​​is greater than the preset congestion evaluation coefficient setting value, then the corresponding sum of the congestion evaluation coefficient values ​​will be used as the cumulative value of the congestion evaluation coefficient.

[0107] Furthermore, the method also includes the following steps:

[0108] If the sum of the blockage evaluation coefficient values ​​is greater than the preset blockage evaluation coefficient setting value, then the calculation of the blockage evaluation coefficient for the preset working condition point will be terminated.

[0109] Furthermore, the method calculates the blockage evaluation coefficient of the operating point based on a preset blockage evaluation coefficient formula;

[0110] The formula for the blockage evaluation coefficient is: in,

[0111] UF is the blockage evaluation coefficient, Pa is the actual urea injection pressure, P is the urea injection target pressure, V1 is the urea injection quantity, V is the urea injection target volume, and Δt is the urea injection time interval.

[0112] Furthermore, the preset first statistical count threshold is 1000;

[0113] The first difference threshold is 10;

[0114] The second difference threshold is 50;

[0115] The second preset judgment period is 10 to 1000 seconds;

[0116] The third preset judgment period is 1 hour.

[0117] In specific implementation, the technical solution based on the embodiments of this application is as follows:

[0118] First, an evaluation coefficient UF is introduced to assess urea filter clogging, and the definition of UF is given:

[0119] As shown in Equation 1-1, UF is the ratio of the actual urea injection pressure to the target pressure, and the ratio of the actual urea injection quantity to the target urea injection quantity. The energy in the exhaust gas is directly proportional to the amount of substance, specific heat capacity, and exhaust gas temperature. The energy required for water evaporation includes heating the water to boiling, evaporating the boiled water into water vapor, and heating the water vapor to the same temperature as the exhaust gas. The energy required for urea hydrolysis includes heating the urea to the decomposition temperature, evaporating the urea into urea vapor, and decomposing the urea vapor into ammonia.

[0120]

[0121] UF is the evaluation coefficient for urea filter clogging, Pa is the actual urea injection pressure (kPa), P is the target urea injection pressure (kPa), V1 is the urea injection volume (ml / s), V is the target volume (L), and Δt is the urea injection time interval (s).

[0122] It should be noted that Pa is measured by a sensor installed in the urea circuit of the urea pump, P is obtained by interpolation based on the urea injection rate using the latest squared method, V1 is the urea injection rate issued by the controller, Δt is the urea injection time interval (range 0.1 to 1 s), and V is the target volume (range 40 to 100 L).

[0123] Second, a diagnostic method for urea filter blockage is proposed:

[0124] 1) Calculate the window time for each operating condition:

[0125] A window-based computation method is proposed, and the window-time curve is illustrated in the attached figure of the specification. Figure 2 As shown, UF is stored in the memory. For each operating point, the value of UF is accumulated backward from the current point. The right boundary of the window is the current operating point. The accumulated value is increased until it exceeds the set value UFmax (range 0.1 to 100). Then the left boundary of the window is defined to obtain the window for that operating point. The window time is calculated. T1 is obtained by subtracting the left window time from the right window time. The window time for each operating point can be obtained by analogy.

[0126] 2) Propose a diagnostic method for urea filter blockage:

[0127] The calculated window time is low-pass filtered to ensure the robustness of the diagnosis, and the window time of each operating point is continuously monitored.

[0128] a) At each moment, a judgment is made. If, Δt time (range 10–1000 s) before the current moment, the minimum value of T is within the range of 10–100 s, and the difference between the maximum and minimum values ​​of T is less than 50, then there is a potential risk of urea filter clogging at the current moment, and the counter is incremented by 1. If the counter is greater than 1000 within 1 hour, the risk indicator for urea filter clogging becomes 1, and an early warning for urea filter clogging is issued. The urea filter clogging curve is shown in the attached figure in the instruction manual. Figure 3 As shown.

[0129] b) At each moment, a judgment is made. If, Δt time (range 10–1000 s) before the current moment, the minimum value of T is within the range of 10–100 s, and the difference between the maximum and minimum values ​​of T is greater than 50, then there is a potential risk of urea filter blockage at the current moment, and the counter is incremented by 1. If the counter is greater than 1000 within 1 hour, the risk indicator for urea pump failure changes to 1, triggering a urea pump malfunction warning. The urea pump malfunction curve is shown in the attached diagram in the instruction manual. Figure 4 As shown.

[0130] Secondly, see Figure 5 As shown, based on the same inventive concept as the method embodiment, this application provides a smart urea filter maintenance device, which includes:

[0131] The window time recording module is used to calculate the cumulative value of the blockage evaluation coefficient at the current working point based on the working status of the urea filter and the urea pump, and to obtain the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold, which is recorded as the first preset comparison period.

[0132] The window time comparison module is used to obtain the difference between the maximum and minimum values ​​of the window time within a preset comparison period, which is denoted as the window time comparison difference.

[0133] The first difference statistics module is used to obtain the difference between the maximum and minimum values ​​of the window time within the first preset comparison period, and record it as the first window time comparison difference of the current working condition point.

[0134] The first determination module is used to obtain the first window time comparison difference between the current working point and all working points from the current working point to the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first set threshold.

[0135] The first recording module is used to increment the first difference count by 1 if the fluctuation difference of the first window time comparison difference in the second preset comparison period is greater than the first difference threshold and less than the second difference threshold.

[0136] The first early warning module is used to issue a urea filter blockage warning if, within a third preset judgment period, the number of times the first difference is counted exceeds a preset first count threshold; wherein...

[0137] The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period.

[0138] The default value for the first difference count is 0.

[0139] It should be noted that the existing technical solution involves periodically maintaining the urea filter by removing and replacing it. The maintenance mileage is related to the size of the urea filter, and the current industry standard is 100,000 kilometers or 1 year. The technical problems with the existing technology are as follows:

[0140] 1) Poor adaptability: Currently, urea filter maintenance is performed according to fixed time or fixed mileage, which is not adaptable;

[0141] If the urea used in the vehicle is of poor quality, it will shorten the maintenance interval, and the vehicle will experience filter clogging problems in advance, which will lead to excessive vehicle emissions, limited torque and speed, and affect vehicle operation.

[0142] If the vehicle uses high-quality urea, the maintenance interval can be extended, reducing vehicle maintenance costs.

[0143] 2) Insufficient predictability: Commercial vehicles operate over a wide area, and there may not be service stations in the areas where the vehicles operate. Clogged urea filters can cause the vehicle to be limited in torque and speed, affecting vehicle operation. If urea filter clogging can be predicted in advance, the vehicle can be replaced in advance, thereby avoiding the impact on the vehicle.

[0144] This application embodiment mainly diagnoses urea filter blockage by diagnosing the difference between the actual pressure and the target pressure of urea injection.

[0145] This technical solution does not require the installation of new sensors or special equipment. It uses information from the vehicle itself to logically determine whether the urea filter is clogged and reminds the driver in advance to go to the service station to maintain the urea filter, thereby avoiding affecting the vehicle's operation.

[0146] Furthermore, the device also includes:

[0147] The second recording module is used to increment the second difference count by 1 if the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the second difference threshold.

[0148] The second early warning module is used to issue a urea pump fault warning if the number of statistical counts of the second difference exceeds a preset second statistical count threshold within the third preset judgment period; wherein...

[0149] The default value for the second difference count is 0.

[0150] Furthermore, the window time recording module is also used to calculate the cumulative value of the blockage evaluation coefficient for the preset working point based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume.

[0151] The window time recording module is also used to obtain the window time corresponding to when the cumulative value of the congestion evaluation coefficient reaches the congestion evaluation coefficient threshold.

[0152] Furthermore, the window time recording module is also used to continuously calculate the blockage evaluation coefficient of the preset working condition point based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, and continuously sum them up, which is recorded as the blockage evaluation coefficient value sum.

[0153] The window time recording module is also used to use the sum of the congestion evaluation coefficients as the cumulative value of the congestion evaluation coefficients if the sum of the congestion evaluation coefficients is greater than the preset congestion evaluation coefficient setting value.

[0154] Furthermore, the device also includes a first termination module, which is used to terminate the calculation of the blockage evaluation coefficient of the preset working condition point if the sum of the blockage evaluation coefficient values ​​is greater than the preset blockage evaluation coefficient setting value.

[0155] Furthermore, the device is equipped with a preset blockage evaluation coefficient formula;

[0156] The formula for the blockage evaluation coefficient is: in,

[0157] UF is the blockage evaluation coefficient, Pa is the actual urea injection pressure, P is the urea injection target pressure, V1 is the urea injection quantity, V is the urea injection target volume, and Δt is the urea injection time interval.

[0158] Furthermore, the preset first statistical count threshold is 1000;

[0159] The first difference threshold is 10;

[0160] The second difference threshold is 50;

[0161] The second preset judgment period is 10 to 1000 seconds;

[0162] The third preset judgment period is 1 hour.

[0163] In specific implementation, the technical solution based on the embodiments of this application is as follows:

[0164] First, an evaluation coefficient UF is introduced to assess urea filter clogging, and the definition of UF is given:

[0165] As shown in Equation 1-1, UF is the ratio of the actual urea injection pressure to the target pressure, and the ratio of the actual urea injection quantity to the target urea injection quantity. The energy in the exhaust gas is directly proportional to the amount of substance, specific heat capacity, and exhaust gas temperature. The energy required for water evaporation includes heating the water to boiling, evaporating the boiled water into water vapor, and heating the water vapor to the same temperature as the exhaust gas. The energy required for urea hydrolysis includes heating the urea to the decomposition temperature, evaporating the urea into urea vapor, and decomposing the urea vapor into ammonia.

[0166]

[0167] UF is the evaluation coefficient for urea filter clogging, Pa is the actual urea injection pressure (kPa), P is the target urea injection pressure (kPa), V1 is the urea injection volume (ml / s), V is the target volume (L), and Δt is the urea injection time interval (s).

[0168] It should be noted that Pa is measured by a sensor installed in the urea circuit of the urea pump, P is obtained by interpolation based on the urea injection rate using the latest squared method, V1 is the urea injection rate issued by the controller, Δt is the urea injection time interval (range 0.1 to 1 s), and V is the target volume (range 40 to 100 L).

[0169] Second, a diagnostic method for urea filter blockage is proposed:

[0170] 1) Calculate the window time for each operating condition:

[0171] A window-based calculation method is proposed. The UF value is stored in the memory. For each operating point, the UF value is accumulated backward from the current point. The right boundary of the window is the current operating point. The accumulated value is defined until it exceeds the set value UFmax (ranging from 0.1 to 100). Then the left boundary of the window is defined to obtain the window for that operating point. The window time is calculated. T1 is obtained by subtracting the left window time from the right window time. The window time for each operating point can be obtained by repeating this process.

[0172] 2) Propose a diagnostic method for urea filter blockage:

[0173] The calculated window time is low-pass filtered to ensure the robustness of the diagnosis, and the window time of each operating point is continuously monitored.

[0174] a) At each moment, a judgment is made. If the minimum value of T is within the range of 10 to 100 seconds before the current moment (Δt time, within the range of 10 to 1000 seconds), and the difference between the maximum value of T and the minimum value of T is less than 50, then there is a potential risk of urea filter blockage at the current moment, and the counter is incremented by 1. If the counter is greater than 1000 within 1 hour, the risk flag of urea filter blockage becomes 1, and an early warning of urea filter blockage is issued.

[0175] b) At each moment, a judgment is made. If the minimum value of T is within the range of 10 to 100 seconds before the current moment (Δt time, within the range of 10 to 1000 seconds), and the difference between the maximum value of T and the minimum value of T is greater than 50, then there is a potential risk of urea filter blockage at the current moment, and the counter is incremented by 1. If the counter is greater than 1000 within 1 hour, the risk flag of urea pump damage becomes 1, and a warning of urea pump failure is issued.

[0176] It should be noted that the technical problems, technical means and technical effects of the intelligent urea filter maintenance device provided in this application embodiment are similar to the principle of the intelligent urea filter maintenance method in terms of principle.

[0177] It should be noted that in this application, relational terms such as "comparison" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, 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 a process, method, article, or apparatus. Without further limitations, 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 the element.

[0178] The above are merely specific embodiments of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A method for intelligent maintenance of urea filter screens, characterized in that, The method includes the following steps: Based on the working conditions of the urea filter and urea pump, the cumulative value of the blockage evaluation coefficient at the current working point is calculated, and the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold is obtained, which is recorded as the first preset comparison period. The difference between the maximum and minimum values ​​of the window time within the first preset comparison period is obtained and recorded as the first window time comparison difference of the current working condition point. Get the first window time comparison difference between the current working point and all working points from the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first preset threshold. If the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the first difference threshold and less than the second difference threshold, then the first difference count is incremented by 1. If, within the third preset judgment period, the number of times the first difference is counted exceeds a preset first count threshold, a urea filter blockage warning will be issued; wherein... The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period. The default value for the first difference count is 0.

2. The intelligent maintenance method for urea filters as described in claim 1, characterized in that, The method further includes the following steps: If the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the second difference threshold, then the second difference count is incremented by 1; If, within the third preset judgment period, the number of times the second difference is counted exceeds a preset second count threshold, a urea pump fault warning is issued; wherein... The default value for the second difference count is 0.

3. The intelligent maintenance method for urea filters as described in claim 1, characterized in that, Based on the operating conditions of the urea filter and urea pump, the cumulative value of the blockage evaluation coefficient at preset operating points is calculated, and the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold is obtained, including the following steps: Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, calculate the cumulative value of the blockage evaluation coefficient for the preset working conditions. Obtain the window time corresponding to when the accumulated value of the congestion evaluation coefficient reaches the congestion evaluation coefficient threshold.

4. The intelligent maintenance method for urea filters as described in claim 3, characterized in that, Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, the cumulative value of the blockage evaluation coefficient at preset operating points is calculated, including the following steps: Based on the actual urea injection pressure, urea injection volume, urea injection time interval, preset urea injection target pressure, and preset urea injection target volume, the blockage evaluation coefficient of the preset working point is continuously calculated and continuously summed, and recorded as the blockage evaluation coefficient value sum. If the sum of the congestion evaluation coefficient values ​​is greater than the preset congestion evaluation coefficient setting value, then the corresponding sum of the congestion evaluation coefficient values ​​will be used as the cumulative value of the congestion evaluation coefficient.

5. The intelligent maintenance method for urea filters as described in claim 4, characterized in that, The method further includes the following steps: If the sum of the blockage evaluation coefficient values ​​is greater than the preset blockage evaluation coefficient setting value, then the calculation of the blockage evaluation coefficient for the preset working condition point will be terminated.

6. The intelligent maintenance method for urea filters as described in claim 3, characterized in that, The method calculates the blockage evaluation coefficient of the operating point based on a preset blockage evaluation coefficient formula; The formula for the blockage evaluation coefficient is: ;in, The congestion evaluation coefficient is... P is the actual pressure of urea injection, V1 is the target pressure of urea injection, V is the urea injection quantity, V is the target volume of urea injection, and Δt is the urea injection time interval.

7. The intelligent maintenance method for urea filters as described in claim 1, characterized in that: The preset first statistical frequency threshold is 1000; The first difference threshold is 10; The second difference threshold is 50; The second preset judgment period is 10~1000s; The third preset judgment period is 1 hour.

8. A smart maintenance device for urea filters, characterized in that, The device includes: The window time recording module is used to calculate the cumulative value of the blockage evaluation coefficient at the current working point based on the working status of the urea filter and the urea pump, and to obtain the window time corresponding to when the cumulative value of the blockage evaluation coefficient reaches the blockage evaluation coefficient threshold, which is recorded as the first preset comparison period. The window time comparison module is used to obtain the difference between the maximum and minimum values ​​of the window time within a preset comparison period, which is denoted as the window time comparison difference. The first difference statistics module is used to obtain the difference between the maximum and minimum values ​​of the window time within the first preset comparison period, and record it as the first window time comparison difference of the current working condition point. The first determination module is used to obtain the first window time comparison difference between the current working point and all working points from the current working point to the second preset comparison period before the current working point, and determine whether the change of the first window time comparison difference exceeds the first set threshold. The first recording module is used to increment the first difference count by 1 if the fluctuation difference of the first window time comparison difference in the second preset comparison period is greater than the first difference threshold and less than the second difference threshold. The first early warning module is used to issue a urea filter blockage warning if, within a third preset judgment period, the number of times the first difference is counted exceeds a preset first count threshold; wherein... The fluctuation difference of the first window time comparison difference in the second preset comparison period is the difference between the maximum value of the first window time comparison difference in the second preset comparison period and the minimum value of the first window time comparison difference in the second preset comparison period. The default value for the first difference count is 0.

9. The intelligent maintenance device for urea filters as described in claim 8, characterized in that, The device further includes: The second recording module is used to increment the second difference count by 1 if the fluctuation difference of the comparison difference in the first window time of the second preset comparison period is greater than the second difference threshold. The second early warning module is used to issue a urea pump fault warning if the number of statistical counts of the second difference exceeds a preset second statistical count threshold within the third preset judgment period; wherein... The default value for the second difference count is 0.

10. The intelligent urea filter maintenance device as described in claim 8, characterized in that, The device is equipped with a preset blockage evaluation coefficient formula; The formula for the blockage evaluation coefficient is: ;in, The congestion evaluation coefficient is... Δt is the actual pressure of urea injection, P is the target pressure of urea injection, V1 is the urea injection quantity, V is the target volume of urea injection, and Δt is the urea injection time interval.

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