Urea pump control method, storage medium and vehicle

Abstract

The present invention belongs to the technical field of diesel engines, and specifically relates to a control method, storage medium and vehicle of a urea pump. The control method of the urea pump in the present invention includes: after the urea pump starts to build pressure, continuously obtaining the urea pump pressure, judging that the urea pump pressure building is completed according to the urea pump pressure being greater than the preset pressure value, obtaining the pressure building time of the urea pump from the start of pressure building to the completion of pressure building according to the urea pump pressure building being completed and the urea nozzle not spraying, and continuously obtaining the urea pump pressure and urea pump duty cycle in the first time period after the pressure building is completed, and controlling the urea pump to perform the first protection measure according to the urea pump pressure in the first time period meeting the first preset pressure condition, the urea pump duty cycle in the first time period meeting the first preset duty cycle condition, and the pressure building time meeting the first preset time condition. By using the control method of the urea pump in the technical solution, the three parameter characteristics are judged according to the corresponding preset conditions respectively, and then the corresponding protection method is implemented.

Description

Technical Field

[0001] The present invention belongs to the technical field of diesel engines, and in particular relates to a control method, a storage medium and a vehicle for a urea pump. Background Art

[0002] The after-treatment system of National VI and non-National IV diesel engines usually requires SCR (selective catalytic reducer) to treat the exhaust gas so that the vehicle emissions meet the emission regulations. Usually, the SCR system eliminates NO in the exhaust gas by injecting urea. x (nitrogen oxides).

[0003] The urea pump includes a urea pump, a urea tank and a urea nozzle. To ensure better reliability and prevent impurities in the urea from causing abnormal wear of the urea pump and clogging of the urea nozzle, the urea pump needs to be equipped with an appropriate filter element. However, in actual use, affected by factors such as the vehicle operating environment and irregular use by users, some impurities will still mix into the urea, causing the performance of the urea pump to deteriorate and the urea pump to become abnormal, thus causing the vehicle's OBD (on-board self-diagnosis system) to fail, torque and speed limits, etc., affecting the normal use of the vehicle, and the urea pump cannot be automatically or autonomously maintained and adjusted. Summary of the invention

[0004] The purpose of the present invention is to at least solve the problem that the urea pump cannot be maintained autonomously when an abnormality or failure occurs. This purpose is achieved through the following technical solutions:

[0005] A first aspect of the present invention provides a control method for a urea pump, comprising:

[0006] When the urea pump starts to build pressure, the urea pump pressure is continuously obtained;

[0007] According to the urea pump pressure being greater than the preset pressure value, it is judged that the urea pump pressure building is completed;

[0008] According to the urea pump pressure building completion and the urea nozzle not spraying, the pressure building time of the urea pump from the start of pressure building to the completion of pressure building is obtained, and the urea pump pressure and the urea pump duty cycle in the first time period after the pressure building is completed are continuously obtained;

[0009] According to the urea pump pressure in the first time period satisfying the first preset pressure condition, the urea pump duty cycle in the first time period satisfying the first preset duty cycle condition, and the pressure building time satisfying the first preset time condition, the urea pump is controlled to perform the first protection measure.

[0010] By using the control method of the urea pump in the technical solution, when the urea pump starts to build pressure, its pressure value is monitored. When the urea pump pressure is greater than the preset pressure value, it can be judged that the urea pump pressure building is completed, and then the pressure building time of the urea pump from the start of pressure building to the completion of pressure building is obtained respectively, and the urea pump pressure and the urea pump duty cycle in the first time period are continuously obtained. When the urea pump pressure in the first time period meets the first preset pressure condition, the urea pump duty cycle in the first time period meets the first preset duty cycle condition, and the pressure building time meets the first preset time condition, it is necessary to perform the first protection measure to maintain it, so as to achieve the purpose of eliminating faults and prolonging the service life of the urea pump. The present invention judges the corresponding preset conditions for the three key parameter characteristics of the pressure building time, the urea pump duty cycle and the urea pump pressure, and then implements the corresponding protection method and measures, which is conducive to improving the adaptability, reliability and application life of the urea pump and improving the overall performance of the vehicle.

[0011] In addition, the control method of the urea pump according to the present invention may also have the following additional technical features:

[0012] In some embodiments of the present invention, the duty cycle of the urea pump in the first time period satisfies the first preset duty cycle condition, which includes:

[0013] According to the urea pump duty cycles corresponding to the at least three first intervals, first duty cycle averages of the urea pump duty cycles in the at least three first intervals are calculated respectively, the first interval is a time period within the first time period, and the at least three first intervals are time periods that are continuous in the first time period, and the first time period further has a second interval after the at least three first intervals;

[0014] According to the first duty cycle averages in at least three first intervals being greater than the first duty cycle average limit, obtaining a second duty cycle average of the urea pump duty cycle in the second interval based on the urea pump duty cycle in the second interval, and obtaining a urea pump duty cycle variance of at least one interval in the first time period according to the urea pump duty cycle in the first time period;

[0015] According to the second duty cycle mean being greater than the second duty cycle mean limit and the urea pump duty cycle variance being greater than the urea pump duty cycle variance limit, it is determined that the urea pump duty cycle in the first time period meets the first preset duty cycle condition.

[0016] In some embodiments of the present invention, the urea pump pressure in the first time period satisfies the first preset pressure condition, which includes:

[0017] Calculating the pressure variance of the urea pump within the third interval according to the corresponding urea pump pressure within the third interval, where the third interval is a time period within the first time period;

[0018] According to the pressure variance of the urea pump being greater than the pressure variance limit, it is determined that the pressure of the urea pump in the first time period meets the first preset pressure condition.

[0019] In some embodiments of the present invention, the pressure building time satisfies the first preset time condition, including:

[0020] According to the pressure building time being less than the preset value of the pressure building time, it is determined that the pressure building time meets the first preset time condition.

[0021] In some embodiments of the present invention, the controlling the urea pump to perform the first protection measure includes:

[0022] Controlling the urea pump to start the protection pressure building mode, adjusting the protection pressure building pressure of the urea pump to a first protection pressure value, and adjusting the duty cycle of the urea pump to a first protection duty cycle value;

[0023] After the urea pump starts the protection pressure building mode to the first protection time, the urea pump is controlled to start the protection back suction mode, and the duty cycle of the urea pump is adjusted to a second protection duty cycle value.

[0024] In some embodiments of the present invention, according to the urea pump pressure in the first time period meeting the first preset pressure condition, the urea pump duty cycle in the first time period meeting the first preset duty cycle condition, and the pressure building time meeting the first preset time condition, after controlling the urea pump to perform the first protection measure, the method further includes:

[0025] According to the urea pump pressure in the first time period satisfying the second preset pressure condition, the urea pump duty cycle in the first time period satisfying the second preset duty cycle condition, and the pressure building time satisfying the second preset time condition, the urea pump is controlled to perform the second protection measure, and the protection degree of the second protection measure is greater than that of the first protection measure.

[0026] In some embodiments of the present invention, the pressure building time satisfies the second preset time condition, including:

[0027] According to the pressure building time being greater than the preset value of the pressure building time, it is determined that the pressure building time meets the second preset time condition.

[0028] In some embodiments of the present invention, the controlling the urea pump to perform the second protection measure includes:

[0029] Controlling the urea pump to start the protection pressure building mode, adjusting the protection pressure building pressure of the urea pump to a second protection pressure value, and adjusting the duty cycle of the urea pump to a third protection duty cycle value;

[0030] After the urea pump starts the protection pressure building mode to the second protection time, the urea pump is controlled to start the protection back suction mode, and the duty cycle of the urea pump is adjusted to a fourth protection duty cycle value;

[0031] The second protection pressure value is greater than the first protection pressure value, the third protection duty cycle value is greater than the first protection duty cycle value, and the fourth protection duty cycle value is greater than the second protection duty cycle value.

[0032] A second aspect of the present invention provides a storage medium, wherein the storage medium stores a computer program or instructions, wherein the computer program or instructions enable a computer to execute the steps of the above-mentioned urea pump control method.

[0033] A third aspect of the present invention provides a vehicle, comprising:

[0034] SCR post-treatment unit;

[0035] A urea injection unit, the urea injection unit comprises a urea tank, a urea pump, and a pressure sensor, wherein the pressure sensor is arranged on the urea pump, the outlet end of the urea tank is connected with the inlet end of the urea pump, the outlet end of the urea pump is provided with a urea nozzle extending into the SCR post-treatment unit, wherein the urea pump is implemented according to the above-mentioned urea pump control method. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Various other advantages and benefits will become apparent to those of ordinary skill in the art by reading the detailed description of the preferred embodiments below. The accompanying drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the present invention. Moreover, the same reference numerals are used throughout the accompanying drawings to represent the same components. In the accompanying drawings:

[0037] Figure 1 A schematic diagram of a control flow chart that satisfies a first preset condition in a control method for a urea pump according to an embodiment of the present invention is schematically shown;

[0038] Figure 2 for Figure 1 A logic diagram of a urea pump control method in which a urea pump duty cycle satisfies a first preset duty cycle condition;

[0039] Figure 3 for Figure 1 A logic diagram of a urea pump control method in which the urea pump pressure satisfies a first preset pressure condition;

[0040] Figure 4 A schematic diagram of a control flow chart that satisfies a second preset condition in a control method for a urea pump according to an embodiment of the present invention is schematically shown;

[0041] Figure 5 The control flow diagram of the overall control method of the urea pump according to the embodiment of the present invention is schematically shown;

[0042] Figure 6The figure schematically shows a connection structure diagram of an SCR post-treatment unit and a urea injection unit in a vehicle according to an embodiment of the present invention.

[0043] The reference numerals in the accompanying drawings represent the following:

[0044] 100. Vehicles;

[0045] 10. SCR post-processing unit; 11. Exhaust temperature sensor; 12. NO x Concentration sensor;

[0046] 21. Urea tank; 211. Temperature sensor; 22. Urea pump; 221. Pressure sensor; 23. Urea nozzle; 24. Urea pipeline;

[0047] 30. Control center. DETAILED DESCRIPTION

[0048] The exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although the exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided in order to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0049] It should be understood that the terms used herein are only for the purpose of describing specific example embodiments and are not intended to be limiting. Unless the context clearly indicates otherwise, the singular forms "one", "an" and "said" as used herein may also be meant to include plural forms. The terms "include", "comprise", "contain", and "have" are inclusive, and therefore specify the existence of stated features, steps, operations, elements and / or parts, but do not exclude the existence or addition of one or more other features, steps, operations, elements, parts, and / or combinations thereof. The method steps, processes, and operations described herein are not interpreted as necessarily requiring them to be performed in the specific order described or illustrated, unless the execution order is clearly indicated. It should also be understood that additional or alternative steps may be used.

[0050] Although the terms first, second, third, etc. can be used in the text to describe multiple elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can only be used to distinguish an element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates, terms such as "first", "second" and other numerical terms do not imply order or sequence when used in the text. Therefore, the first element, component, region, layer or section discussed below can be referred to as the second element, component, region, layer or section without departing from the teaching of the example embodiments.

[0051] For ease of description, spatial relative terms may be used herein to describe the relationship of one element or feature relative to another element or feature as shown in the figure, such as "inside", "outside", "inner side", "outer side", "below", "below", "above", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figure. For example, if the device in the figure is turned over, then the elements described as "below other elements or features" or "below other elements or features" will subsequently be oriented as "above other elements or features" or "above other elements or features". Therefore, the example term "below..." can include both upper and lower orientations. The device can be oriented otherwise (rotated 90 degrees or in other directions) and the spatial relative descriptors used in the text are interpreted accordingly.

[0052] Figure 1 The control flow diagram of the control method of the urea pump according to the embodiment of the present invention that satisfies the first preset condition is schematically shown. Figure 1 As shown, the present invention proposes a control method for a urea pump, a storage medium and a vehicle. The control method for a urea pump in the present invention includes:

[0053] S110: After the urea pump starts to build pressure, the urea pump pressure is continuously obtained;

[0054] S120: judging that the urea pump pressure is greater than the preset pressure value, that the urea pump pressure building is completed;

[0055] S130: according to the urea pump pressure building completion and the urea nozzle not spraying, obtaining the pressure building time of the urea pump from the start of pressure building to the completion of pressure building, and continuously obtaining the urea pump pressure and the urea pump duty cycle in the first time period after the pressure building is completed;

[0056] S140: According to the urea pump pressure in the first time period satisfying the first preset pressure condition, the urea pump duty cycle in the first time period satisfying the first preset duty cycle condition, and the pressure building time satisfying the first preset time condition, controlling the urea pump to perform a first protection measure.

[0057] By using the control method of the urea pump in the technical solution, when the urea pump starts to build pressure, its pressure value is monitored. When the urea pump pressure is greater than the preset pressure value, it can be judged that the urea pump pressure building is completed, and then the pressure building time of the urea pump from the start of pressure building to the completion of pressure building is obtained respectively, and the urea pump pressure and the urea pump duty cycle in the first time period are continuously obtained. When the urea pump pressure in the first time period meets the first preset pressure condition, the urea pump duty cycle in the first time period meets the first preset duty cycle condition, and the pressure building time meets the first preset time condition, it is necessary to perform the first protection measure to maintain it, so as to achieve the purpose of eliminating faults and prolonging the service life of the urea pump. The present invention judges the corresponding preset conditions for the three key parameter characteristics of the pressure building time, the urea pump duty cycle and the urea pump pressure, and then implements the corresponding protection method and measures, which is conducive to improving the adaptability, reliability and application life of the urea pump and improving the overall performance of the vehicle.

[0058] Specifically, in this embodiment, the urea pump pressure and the urea pump duty cycle in the first time period after the pressure building is completed are continuously obtained: so that a lot of urea pump pressure values ​​and a lot of urea pump duty cycle values ​​can be obtained in the first time period.

[0059] Specifically, in the present embodiment, the urea pump has a first state and a second state during the pressure building process. The urea pump is in the first state when it starts to build pressure (the urea pump pressure reaches P1 at this time, and P1 may be 1000 hPa). When the urea pump completes the pressure building, it is in the second state (the urea pump pressure reaches P2 at this time, and P2 may be 9000 hPa, and the pressure fluctuation of the urea pump is less than the fluctuation limit at this time).

[0060] In some embodiments of the present invention, Figure 2 As shown, the duty cycle of the urea pump in the first time period satisfies the first preset duty cycle condition including:

[0061] S210: calculating first duty cycle averages of the urea pump duty cycles in at least three first intervals, according to the duty cycles of the urea pumps corresponding to the at least three first intervals, respectively, wherein the first interval is a time period within the first time period, and the at least three first intervals are time periods that are continuous within the first time period, and the first time period further includes a second interval after the at least three first intervals;

[0062] S220: according to the first duty cycle averages in at least three first intervals being greater than the first duty cycle average limit, obtaining a second duty cycle average of the urea pump duty cycle in the second interval based on the urea pump duty cycle in the second interval, and obtaining a urea pump duty cycle variance of at least one interval in the first time period according to the urea pump duty cycle in the first time period;

[0063] S230: According to the second duty cycle mean being greater than the second duty cycle mean limit and the urea pump duty cycle variance being greater than the urea pump duty cycle variance limit, it is determined that the urea pump duty cycle in the first time period meets the first preset duty cycle condition.

[0064] Specifically, in this embodiment, the urea pump duty cycle of a fixed mileage (which can be 1000km) at multiple time points in the first time period is continuously obtained, and the urea pump duty cycle mean value in at least three first intervals in the first time period is calculated by the urea pump duty cycle at multiple time points, and at least three first intervals are continuous intervals. If the urea pump duty cycle mean value is represented by a variable k, the urea pump duty cycle mean value in at least three first intervals in the first time period can be represented by k1, k2 and k3 (if there are more than three continuous first intervals, then the same applies). Under normal circumstances, the urea pump duty cycle has no significant degradation. When the urea pump deteriorates (such as irregular urea causing the filter element to be dirty and blocked), the urea pump duty cycle will increase significantly. Based on the above rules, the average value of the urea pump duty cycle is used as the key characteristic parameter of the urea pump of 1000 kilometers.

[0065] Specifically, the duty cycle of the urea pump at multiple time points in the first time period with a fixed mileage (which can be 1000km) is continuously obtained, and the variance of the duty cycle of the urea pump in at least one first interval in the first time period is calculated through the duty cycle of the urea pump at multiple time points. According to the above second duty cycle mean being greater than the second duty cycle mean limit, and the urea pump pressure variance being greater than the urea pump pressure variance limit, it is judged that the urea pump pressure in the first time period meets the first preset pressure condition. Under normal circumstances, the duty cycle fluctuates less and the variance is smaller; after the system deteriorates, its fluctuation intensifies and the variance increases significantly. Based on the above rules, the variance of the urea pump duty cycle is used as the key characteristic parameter of the urea pump for this 1000 km.

[0066] In some embodiments of the present invention, Figure 3 As shown, the urea pump pressure in the first time period meets the first preset pressure condition including:

[0067] S310: calculating the pressure variance of the urea pump in the third interval according to the corresponding urea pump pressure in the third interval, where the third interval is a time period in the first time period;

[0068] S320: According to the pressure variance of the urea pump being greater than the pressure variance limit, it is determined that the pressure of the urea pump in the first time period meets a first preset pressure condition.

[0069] Specifically, under normal circumstances, after the urea pump pressure is built up, the urea pump reaches a preset pressure value with small fluctuations. When the system deteriorates (such as irregular urea causing the filter element to be dirty and blocked, urea pump performance degradation, etc.), the urea pump pressure fluctuation increases. The present invention calculates the urea pump pressure variance according to a fixed mileage (1000km) set in the first time period, and counts the urea pump pressure variance when the urea pump pressure is built up within every 1000 kilometers.

[0070] In some embodiments of the present invention, the pressure building time satisfies the first preset time condition including:

[0071] According to the pressure building time being less than the preset value of the pressure building time, it is determined that the pressure building time meets the first preset time condition.

[0072] Specifically, when the urea pump deteriorates (commonly caused by filter clogging), the pressure building time will be longer.

[0073] It can be seen that the following conditions are set in the present invention to monitor the urea pump:

[0074] Condition a: Calculate the average duty cycle of the urea pump at different first intervals through multiple urea pump duty cycles in the first time period. If the average duty cycle of the urea pump in at least three consecutive first intervals is greater than the first duty cycle average limit max1 (such as 35%), that is, k i >max1,k i+1 >max1,k i+2 >max1, it indicates that the urea pump is initially degraded, and based on the above conditions, the following judgment is made again: if the second duty cycle average of the second interval time after at least three consecutive interval times in the first time period is greater than the second duty cycle average limit (such as 45%), it means that after the urea pump is initially degraded, its performance may further decline, resulting in a further increase in the urea pump duty cycle.

[0075] Condition b: From k i-1 The urea pump duty cycle variance of at least one interval time within the first time period at the beginning is greater than the urea pump duty cycle variance limit value v max (e.g. 30). This shows that within the normal range, the duty cycle fluctuates slightly and has a small variance; after the system deteriorates, its fluctuation intensifies and the variance increases significantly.

[0076] Condition c: the corresponding urea pump pressure during the third interval is greater than the pressure variance of the urea pump (eg, 0.03).

[0077] If the urea pump satisfies the above conditions a, b and c at the same time, and the pressure building time is less than the preset pressure building time value, the urea pump is controlled to perform the first protection measure to maintain the urea pump.

[0078] In some embodiments of the present invention, controlling the urea pump to perform the first protection measure includes:

[0079] Controlling the urea pump to start the protection pressure building mode, adjusting the protection pressure building pressure of the urea pump to a first protection pressure value, and adjusting the duty cycle of the urea pump to a first protection duty cycle value;

[0080] After the urea pump starts the protection pressure building mode to the first protection time, the urea pump is controlled to start the protection back suction mode, and the duty cycle of the urea pump is adjusted to a second protection duty cycle value.

[0081] Specifically, in this embodiment, if Figure 5 As shown in the figure, when the urea pump meets conditions a, b and c at the same time, it is confirmed that the urea pump is abnormal and the urea pump fault state alarm st =1 (fault state 1), when the vehicle has no urea injection requirement (T scr (Exhaust gas temperature upstream of SCR) <T min ), the urea pump starts the protection pressure building mode and the protection back suction mode in sequence to strongly stimulate and recoil the inside of the urea pump and the inside of the urea pipeline, so as to solve the problems of possible minor impurity blockage. Among them, in the protection pressure building mode, the protection pressure building pressure (such as 10000hPa) is greater than P1 (1000hPa) reached in the first state of the urea pump, and the duty cycle of the urea pump during the pressure building process is adjusted to the first protection duty cycle value (the first protection duty cycle value can be 60%, and is greater than the duty cycle setting value of the urea pump during the normal pressure building process). The duty cycle of the urea pump in the protection back suction mode is adjusted to the second protection duty cycle value (the first protection duty cycle value can be 80%, and is greater than the duty cycle setting value of the urea pump during the normal pressure building process), and the total protection time of the protection pressure building mode and the protection back suction mode is t1.

[0082] In some embodiments of the present invention, Figure 1 As shown, according to the urea pump pressure in the first time period meeting the first preset pressure condition, the urea pump duty cycle in the first time period meeting the first preset duty cycle condition, and the pressure building time meeting the first preset time condition, after controlling the urea pump to perform the first protection measure, the following further includes:

[0083] S410: After the urea pump starts to build pressure, the urea pump pressure is continuously obtained;

[0084] S420: judging that the urea pump pressure is greater than the preset pressure value, that the urea pump pressure building is completed;

[0085] S430: according to the urea pump pressure building completion and the urea nozzle not spraying, obtaining the pressure building time of the urea pump from the start of pressure building to the completion of pressure building, and continuously obtaining the urea pump pressure and the urea pump duty cycle in the first time period after the pressure building is completed;

[0086] S440: Based on the urea pump pressure in the first time period satisfying the second preset pressure condition, the urea pump duty cycle in the first time period satisfying the second preset duty cycle condition, and the pressure building time satisfying the second preset time condition, the urea pump is controlled to perform a second protection measure, and the protection degree of the second protection measure is greater than that of the first protection measure.

[0087] Specifically, in this embodiment, the first protection measure and the second protection measure implement different protection degrees, and the protection degree of the second protection measure is greater than that of the first protection measure, indicating that the urea pump is more deteriorated under the second protection measure. In addition, the second preset pressure condition in this embodiment is the same as the first preset pressure condition in the first protection measure, and the second preset duty cycle condition is the same as the first preset duty cycle condition in the first protection measure.

[0088] In some embodiments of the present invention, the pressure building time satisfies the second preset time condition including:

[0089] According to the pressure building time being greater than the preset value of the pressure building time, it is determined that the pressure building time meets the second preset time condition.

[0090] In some embodiments of the present invention, controlling the urea pump to perform the second protection measure includes:

[0091] Controlling the urea pump to start the protection pressure building mode, adjusting the protection pressure building pressure of the urea pump to a second protection pressure value, and adjusting the duty cycle of the urea pump to a third protection duty cycle value;

[0092] After the urea pump starts the protection pressure building mode to the second protection time, the urea pump is controlled to start the protection back suction mode, and the duty cycle of the urea pump is adjusted to a fourth protection duty cycle value;

[0093] The second protection pressure value is greater than the first protection pressure value, the third protection duty cycle value is greater than the first protection duty cycle value, and the fourth protection duty cycle value is greater than the second protection duty cycle value.

[0094] Specifically, in this embodiment, the second protection measure is the same as a, b and c of the first protection measure, and the difference is the judgment of the pressure building time. If the urea pump satisfies the above conditions a, b and c at the same time, and the pressure building time is greater than the preset value of the pressure building time, it means that the urea pump pressure, the urea pump duty cycle and the pressure building time meet their respective preset conditions, and the urea pump is controlled to perform the second protection measure to maintain the urea pump. The present invention can judge the first preset condition and the second preset condition of the three key parameter characteristics of the pressure building time, the urea pump duty cycle and the urea pump pressure, and then implement different protection methods and measures, thereby improving the maintenance efficiency and service life of the urea pump.

[0095] Specifically, in this embodiment, if Figure 5 As shown in the figure, when the urea pump meets conditions a, b and c at the same time, and the pressure build-up time is greater than the preset time value, it is confirmed that the urea pump is abnormal, and the urea pump fault state alarm st =2 (fault state 2), the degradation degree of the urea pump is greater than the above fault state equal to 1, and a more powerful active protection method needs to be implemented. When the vehicle has no urea injection demand (T scr (Exhaust gas temperature upstream of SCR) <T min ), the protection pressure building mode and the protection back suction mode are started by the urea pump to strongly stimulate and recoil the inside of the urea pump and the inside of the urea pipeline, so as to solve the problems of possible minor impurity blockage. Among them, in the protection pressure building mode, the protection pressure building pressure (such as 11000hPa) is greater than P1 (1000hPa) reached in the first state of the urea pump, and the duty cycle of the urea pump during the pressure building process is adjusted to the third protection duty cycle value (the third protection duty cycle value can be 70%, and is greater than the duty cycle setting value of the urea pump in the normal pressure building process). The duty cycle of the urea pump in the protection back suction mode is adjusted to the fourth protection duty cycle value (the fourth protection duty cycle value can be 85%, and is greater than the duty cycle setting value of the urea pump in the normal pressure building process), and the total protection time of the protection pressure building mode and the protection back suction mode is t2 (t2 is greater than t1). In this embodiment, t1 and t2 are specifically defined according to the specific situation, and this value is not specifically set in the present invention.

[0096] In some embodiments of the present invention, the second protection pressure value is greater than the first protection pressure value, the third protection duty cycle value is greater than the first protection duty cycle value, and the fourth protection duty cycle value is greater than the second protection duty cycle value. In this embodiment, the first protection pressure value, the second protection pressure value, the third protection pressure value and the fourth protection pressure value are all specifically limited according to specific circumstances, and the present invention does not specifically set this value. The second preset condition is more deteriorated than the first preset condition, so the value of the second preset condition is selected to be larger than that of the first preset condition.

[0097] Specifically, in the present invention, the pressure preset value, the first duty cycle mean limit value, the second duty cycle mean limit value, the urea pump duty cycle variance limit value, the pressure variance limit value, the pressure buildup time preset value, the first protection pressure value, the second protection pressure value, the first protection duty cycle value and the second protection duty cycle value, the third protection duty cycle value and the fourth protection duty cycle value are all specifically limited according to the specific circumstances, and these values ​​are not specifically set in the present invention.

[0098] Furthermore, if Figure 5 As shown, the present invention comprehensively considers the changing rules of various key characteristic parameters after the urea pump deteriorates, including the duty cycle of the urea pump, the urea pump pressure, and the pressure building time, and makes a detailed monitoring scheme based on the mean, variance, etc. of the key characteristic parameters in the normal state and the deteriorated state. In addition, different degrees of active protection methods can be implemented according to the current degree of degradation of the urea pump, which is beneficial to improving the adaptability, reliability and service life of the urea injection system and improving the overall performance of the vehicle.

[0099] A second aspect of the present invention provides a storage medium, wherein the storage medium stores a computer program or instructions, and the computer program or instructions enable a computer to execute the steps of the above-mentioned urea pump control method.

[0100] Those skilled in the art will further appreciate that the various illustrative logic blocks, modules, circuits, and algorithm steps described in conjunction with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or a combination of the two. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps are generally described above in terms of their functionality. Whether such functionality is implemented as hardware or software depends on the specific application and the design constraints imposed on the overall system. The technician may implement the described functionality in different ways for each specific application, but such implementation decisions should not be interpreted as resulting in a departure from the scope of the present invention.

[0101] The various illustrative logic modules and circuits described in conjunction with the embodiments disclosed herein may be implemented or executed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in cooperation with a DSP core, or any other such configuration.

[0102] In one or more exemplary embodiments, the functions described may be implemented in hardware, software, firmware, or any combination thereof. If implemented as a computer program product in software, each function may be stored on or transmitted by a computer-readable medium as one or more instructions or codes. Computer-readable media include both computer storage media and communication media, including any medium that facilitates the transfer of a computer program from one place to another. Storage media may be any available medium that can be accessed by a computer. As an example and not limitation, such a computer-readable medium may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, disk storage or other magnetic storage device, or any other medium that can be used to carry or store the desired program code in the form of an instruction or data structure and can be accessed by a computer. Any connection is also properly referred to as a computer-readable medium. For example, if the software is transmitted from a website, a server, or other remote source using a coaxial cable, a fiber optic cable, a twisted pair, a digital subscriber line (DSL), or wireless technologies such as infrared, radio, and microwaves, the coaxial cable, fiber optic cable, twisted pair, DSL, or wireless technologies such as infrared, radio, and microwaves are included in the definition of the medium. As used herein, disk and disc include compact disc (CD), laser disc, optical disc, digital versatile disc (DVD), floppy disk and Blu-ray disc, wherein disk often reproduces data magnetically, while disc reproduces data optically with lasers. Combinations of the above should also be included within the scope of storage media.

[0103] A third aspect of the present invention provides a vehicle, such as Figure 6 As shown, including:

[0104] SCR post-treatment unit 10;

[0105] The urea injection unit includes a urea tank 21, a urea pump 22, and a pressure sensor 221. The pressure sensor 221 is arranged on the urea pump 22. The outlet end of the urea tank 21 is connected to the inlet end of the urea pump 22. The outlet end of the urea pump 22 is provided with a urea nozzle 23 extending into the SCR post-treatment unit 10. The urea pump 22 is implemented according to the above-mentioned control method of the urea pump 22.

[0106] Specifically, in the present embodiment, the urea injection system includes a urea tank 21, a urea tank 21 temperature sensor 211 disposed on the urea tank 21, a urea pump 22, a urea pump 22 pressure sensor 221 disposed on the urea pump 22, a urea pipeline 24, and a urea nozzle 23 facing the SCR post-processing unit 10 and used for injecting urea solution, an exhaust temperature sensor 11 is disposed on the exhaust treatment pipe section upstream of the SCR post-processing unit 10, and a NOx concentration sensor 12 is disposed on the exhaust treatment pipe section downstream of the SCR post-processing unit 10. The urea tank 21, the temperature sensor 211, the urea pump 22, the pressure sensor 221, the SCR post-processing unit 10, the exhaust temperature sensor 11, and the NOx concentration sensor 12 in the present embodiment are all electrically connected to the engine control center 30.

[0107] The above is only a preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any changes or substitutions that can be easily thought of by a person skilled in the art within the technical scope disclosed by the present invention should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A method for controlling a urea pump, characterized in that: include: When the urea pump starts to build pressure, the urea pump pressure is continuously obtained; According to the urea pump pressure being greater than the preset pressure value, it is judged that the urea pump pressure building is completed; According to the urea pump pressure building completion and the urea nozzle not spraying, the pressure building time of the urea pump from the start of pressure building to the completion of pressure building is obtained, and the urea pump pressure and the urea pump duty cycle in the first time period after the pressure building is completed are continuously obtained; According to the urea pump pressure in the first time period meeting the first preset pressure condition, the urea pump duty cycle in the first time period meeting the first preset duty cycle condition, and the pressure building time meeting the first preset time condition, controlling the urea pump to perform the first protection measure; The duty cycle of the urea pump in the first time period satisfies the first preset duty cycle condition including: According to the urea pump duty cycles corresponding to the at least three first intervals, first duty cycle averages of the urea pump duty cycles in the at least three first intervals are calculated respectively, the first interval is a time period within the first time period, and the at least three first intervals are time periods that are continuous in the first time period, and the first time period further has a second interval after the at least three first intervals; According to the first duty cycle averages in at least three first intervals being greater than the first duty cycle average limit, obtaining a second duty cycle average of the urea pump duty cycle in the second interval based on the urea pump duty cycle in the second interval, and obtaining a urea pump duty cycle variance of at least one interval in the first time period according to the urea pump duty cycle in the first time period; According to the second duty cycle mean being greater than the second duty cycle mean limit, and the urea pump duty cycle variance being greater than the urea pump duty cycle variance limit, it is determined that the urea pump duty cycle in the first time period meets the first preset duty cycle condition; The urea pump pressure in the first time period meets the first preset pressure condition including: Calculating the pressure variance of the urea pump within the third interval according to the corresponding urea pump pressure within the third interval, where the third interval is a time period within the first time period; According to the pressure variance of the urea pump being greater than the pressure variance limit, it is determined that the pressure of the urea pump in the first time period meets the first preset pressure condition; The pressure building time meets the first preset time condition including: According to the pressure building time being less than the preset value of the pressure building time, it is determined that the pressure building time meets the first preset time condition.

2. The control method of the urea pump according to claim 1, characterized in that: The controlling of the urea pump to perform the first protection measure includes: Controlling the urea pump to start the protection pressure building mode, adjusting the protection pressure building pressure of the urea pump to a first protection pressure value, and adjusting the duty cycle of the urea pump to a first protection duty cycle value; After the urea pump starts the protection pressure building mode to the first protection time, the urea pump is controlled to start the protection back suction mode, and the duty cycle of the urea pump is adjusted to a second protection duty cycle value.

3. The control method of the urea pump according to claim 2, characterized in that: According to the urea pump pressure in the first time period meeting the first preset pressure condition, the urea pump duty cycle in the first time period meeting the first preset duty cycle condition, and the pressure building time meeting the first preset time condition, after controlling the urea pump to perform the first protection measure, the method further includes: According to the urea pump pressure in the first time period satisfying the second preset pressure condition, the urea pump duty cycle in the first time period satisfying the second preset duty cycle condition, and the pressure building time satisfying the second preset time condition, the urea pump is controlled to perform the second protection measure, and the protection degree of the second protection measure is greater than that of the first protection measure.

4. The control method of the urea pump according to claim 3, characterized in that: The pressure building time meets the second preset time condition including: According to the pressure building time being greater than the preset value of the pressure building time, it is determined that the pressure building time meets the second preset time condition.

5. The control method of the urea pump according to claim 3, characterized in that: The second protection measure of controlling the urea pump includes: Controlling the urea pump to start the protection pressure building mode, adjusting the protection pressure building pressure of the urea pump to a second protection pressure value, and adjusting the duty cycle of the urea pump to a third protection duty cycle value; After the urea pump starts the protection pressure building mode to the second protection time, the urea pump is controlled to start the protection back suction mode, and the duty cycle of the urea pump is adjusted to a fourth protection duty cycle value; The second protection pressure value is greater than the first protection pressure value, the third protection duty cycle value is greater than the first protection duty cycle value, and the fourth protection duty cycle value is greater than the second protection duty cycle value.

6. A storage medium, characterized in that: The storage medium stores a computer program or instructions, and the computer program or instructions enable a computer to execute the steps of the urea pump control method according to any one of claims 1 to 5.

7. A vehicle, characterized in that: include: SCR post-treatment unit; A urea injection unit, the urea injection unit comprises a urea tank, a urea pump, and a pressure sensor, the pressure sensor is arranged on the urea pump, the outlet end of the urea tank is connected with the inlet end of the urea pump, the outlet end of the urea pump is provided with a urea nozzle extending into the SCR post-treatment unit, wherein the urea pump is implemented according to the control method of the urea pump according to any one of claims 1 to 5.

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