Cooling system fault diagnosis method, device, electronic equipment and storage medium

Abstract

The embodiments of the present application disclose a method, device, electronic device, and storage medium for diagnosing a cooling system fault. The method includes: obtaining the detected temperature of the cooling system, the actual speed of the electronic water pump, and the actual rotation angle of the temperature control module; determining the theoretical inlet branch flow and the theoretical outlet branch flow of the electronic water pump based on the actual speed of the electronic water pump and the actual rotation angle of the temperature control module; correcting the theoretical inlet branch flow and the theoretical outlet branch flow based on the detected temperature to obtain the actual inlet branch flow and the actual outlet branch flow; determining the outlet temperature of the expansion water tank based on the actual inlet branch flow and the actual outlet branch flow; and diagnosing a cooling system fault based on the outlet temperature of the expansion water tank. In this way, on the one hand, a more accurate actual value can be obtained by correcting the theoretical value; on the other hand, the outlet temperature of the expansion water tank can be used to perform fault diagnosis under different vehicle operating conditions, thereby improving the accuracy of fault diagnosis.

Description

Technical Field

[0001] The present application relates to the field of vehicle control technology, and in particular to a method, device, electronic device, and computer-readable storage medium for determining a cooling system fault. Background Art

[0002] Currently, the cooling systems for heat-generating components in vehicles on the market, such as engines, batteries, and motors, are essentially automated. These components are cooled by the cooling system to maintain stable vehicle operation. When an internal leakage occurs in the cooling system, the coolant, which should be flowing in the small circulation branch while the cooling system is required to accumulate heat, can easily flow into the radiator, where it should not flow. This results in unnecessary heat dissipation, preventing the cooling system from completing its warm-up phase and maintaining a low temperature for an extended period. This, in turn, can cause the oil temperature to be too low, resulting in higher viscosity, increased friction losses, higher fuel consumption, and possible oil dilution. Furthermore, insufficient system temperature can easily lead to insufficient warm air supply, affecting system comfort. Therefore, it is necessary to promptly diagnose faults in the vehicle's cooling system.

[0003] At present, the relevant technology is to add a temperature sensor at the radiator outlet position, and perform fault diagnosis by detecting the vehicle speed and water temperature after the vehicle is started. However, due to the influence of environmental, weather and other factors, the parameter detection error is large under different working conditions, and this method is only applicable to fault diagnosis during the vehicle's cold start warm-up process, which can easily lead to inaccurate fault diagnosis of the cooling system. Summary of the Invention

[0004] To solve the above technical problems, the embodiments of the present application provide a method for determining a cooling system fault, a device for determining a cooling system fault, an electronic device, and a computer-readable storage medium, so as to improve the accuracy of determining a fault in a vehicle's cooling system.

[0005] According to one aspect of an embodiment of the present application, a method for judging a cooling system fault is provided, wherein the cooling system is applied to a vehicle, and the cooling system includes an electronic water pump, a temperature control module and an expansion water tank; the electronic water pump is used to controllably adjust the coolant flow in the cooling system, the temperature control module is used to controllably adjust the flow and on / off of each branch of the electronic water pump, and the expansion water tank is used to store coolant; the method includes: obtaining a detected temperature of the cooling system, an actual speed of the electronic water pump and an actual rotation angle of the temperature control module; determining a theoretical inlet branch flow and a theoretical outlet branch flow of the electronic water pump according to the actual speed of the electronic water pump and the actual rotation angle of the temperature control module; correcting the theoretical inlet branch flow and the theoretical outlet branch flow according to the detected temperature to obtain an actual inlet branch flow and an actual outlet branch flow; determining the outlet temperature of the expansion water tank according to the actual inlet branch flow and the actual outlet branch flow; and judging a fault of the cooling system according to the outlet temperature of the expansion water tank.

[0006] In some embodiments, the theoretical inlet branch flow and the theoretical outlet branch flow of the electronic water pump are determined based on the actual speed of the electronic water pump and the actual rotation angle of the temperature control module, including: performing a table lookup operation using the actual speed of the electronic water pump and the actual rotation angle of the temperature control module to obtain the theoretical inlet branch flow and the theoretical outlet branch flow.

[0007] In some embodiments, the theoretical inlet branch flow and the theoretical outlet branch flow are respectively corrected according to the detected temperature to obtain the actual inlet branch flow and the actual outlet branch flow, including: summing the theoretical inlet branch flows to obtain the theoretical total inlet flow; and summing the theoretical outlet branch flows to obtain the theoretical total outlet flow; obtaining the proportion of the theoretical inlet branch flow to the theoretical inlet total flow; and obtaining the proportion of the theoretical outlet branch flow to the theoretical outlet total flow; obtaining the thermal state characterization temperature of the cooling system according to the detected temperature and the proportion of the outlet branch flow; determining a correction coefficient according to the thermal state characterization temperature; correcting the theoretical total inlet flow according to the correction coefficient to obtain the actual total inlet flow; and correcting the theoretical total outlet flow according to the correction coefficient to obtain the actual total outlet flow; determining the actual inlet branch flow according to the actual total inlet flow and the proportion of the inlet branch flow, and determining the actual outlet branch flow according to the actual total outlet flow and the proportion of the outlet branch flow.

[0008] In some embodiments, determining the correction coefficient according to the thermal state representative temperature includes: acquiring the ambient temperature; and performing a table lookup operation according to the thermal state representative temperature and the ambient temperature to obtain the correction coefficient.

[0009] In some embodiments, the actual inlet branch flow includes the actual outlet flow of the expansion tank, the actual outlet flow of the radiator and the actual flow of the small circulation branch; the outlet temperature of the expansion tank includes the outlet temperature of the expansion tank in the downstream direction and the outlet temperature of the expansion tank in the upstream direction; the outlet temperature of the expansion tank is determined according to the actual inlet branch flow and the actual outlet branch flow, including: determining the inlet flow of the expansion tank according to the actual outlet flow of the expansion tank and a preset overflow ratio; and determining the internal temperature of the temperature control module according to the detected temperature and the actual outlet branch flow; obtaining the flow temperature of the inlet flow of the expansion tank; weighting the flow temperature according to the actual outlet flow of the expansion tank and the inlet flow of the expansion tank to obtain the outlet temperature of the expansion tank in the downstream direction; and determining the outlet temperature of the expansion tank in the upstream direction according to the actual outlet flow of the radiator, the actual flow of the small circulation branch and the internal temperature of the temperature control module.

[0010] In some embodiments, fault diagnosis of the cooling system is performed based on the outlet temperature of the expansion water tank, including: obtaining multiple temperature differences between the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the reverse direction within a preset time period; obtaining an average value of the temperature differences of the multiple temperature differences; and fault diagnosis of the cooling system is performed based on the average value of the temperature differences.

[0011] In some embodiments, a fault judgment is performed on the cooling system based on the average temperature difference, including: when the average temperature difference is greater than a preset threshold, the cumulative number of faults is accumulated once; when the cumulative number of faults reaches a preset number, it is determined that an internal leakage fault has occurred in the cooling system.

[0012] According to one aspect of an embodiment of the present application, a device for diagnosing a cooling system fault is provided. The cooling system is applied to a vehicle and includes an electronic water pump, a temperature control module, and an expansion water tank. The electronic water pump is used to control and adjust the coolant flow in the cooling system. The temperature control module is used to control and adjust the flow and on / off of each branch of the electronic water pump. The expansion water tank is used to store coolant. The device includes: an acquisition module configured to obtain a detected temperature of the cooling system, an actual speed of the electronic water pump, and an actual rotation angle of the temperature control module; a first determination module configured to determine a theoretical inlet branch flow and a theoretical outlet branch flow of the electronic water pump based on the actual speed of the electronic water pump and the actual rotation angle of the temperature control module; a correction module configured to correct the theoretical inlet branch flow and the theoretical outlet branch flow according to the detected temperature to obtain actual inlet branch flow and actual outlet branch flow; a second determination module configured to determine the outlet temperature of the expansion water tank based on the actual inlet branch flow and actual outlet branch flow; and a judgment module configured to perform a fault diagnosis on the cooling system based on the outlet temperature of the expansion water tank.

[0013] According to one aspect of an embodiment of the present application, an electronic device is provided, comprising one or more processors; and a storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the above-mentioned method for determining a cooling system fault.

[0014] According to one aspect of an embodiment of the present application, a computer-readable storage medium is provided, on which a computer program is stored. When the computer program is executed by a processor, the method for determining a cooling system fault as described above is implemented.

[0015] In the technical solution provided in the embodiments of the present application, on the one hand, by correcting the detected theoretical branch flow, a more accurate actual branch flow can be obtained, which facilitates more accurate determination of the outlet temperature of the expansion tank; on the other hand, there is no need to add a temperature sensor at the radiator outlet to detect the outlet temperature. Through the outlet temperature of the expansion tank, the cooling system can be accurately judged for faults under different vehicle operating scenarios, thereby improving the accuracy of fault judgment of the cooling system.

[0016] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the present application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The accompanying drawings are incorporated into and constitute a part of the specification, illustrating embodiments consistent with the present application and, together with the specification, serving to explain the principles of the present application. It is obvious that the drawings described below are merely some embodiments of the present application, and a person of ordinary skill in the art can derive other drawings based on these drawings without inventive effort. In the drawings:

[0018] Figure 1 is a structural schematic diagram of a cooling system shown in an exemplary embodiment of the present application;

[0019] Figure 2 is a flow chart of a method for determining a cooling system fault according to an exemplary embodiment of the present application;

[0020] Figure 3 yes Figure 2 Step S230 in the illustrated embodiment is a flow chart of a method for obtaining an actual inlet branch flow rate and an actual outlet branch flow rate in an exemplary embodiment;

[0021] Figure 4 yes Figure 2 Step S250 in the illustrated embodiment is a flow chart of a method for determining a fault in a cooling system based on the outlet temperature of the expansion water tank in an exemplary embodiment;

[0022] Figure 5 It is a structural diagram of a device for determining a cooling system fault according to an exemplary embodiment of the present application.

[0023] Reference numerals:

[0024] 1: Engine cylinder head; 2: Engine block; 3: Oil cooler; 4: Electronic water pump; 5: Temperature control module; 6: Radiator; 7: Expansion tank; 8: Exhaust manifold; 9: Heater core; 10: First water temperature sensor; 11: Second water temperature sensor; 12: Third water temperature sensor; 13: Fourth water temperature sensor. DETAILED DESCRIPTION

[0025] Exemplary embodiments will be described in detail herein, with examples illustrated in the accompanying drawings. When the following description refers to the drawings, identical numerals in different figures represent identical or similar elements, unless otherwise indicated. The embodiments described in the following exemplary embodiments are not intended to represent all embodiments applicable to the present application. Rather, they are merely examples of apparatus and methods applicable to certain aspects of the present application, as detailed in the appended claims.

[0026] The block diagrams shown in the accompanying drawings are merely functional entities and do not necessarily correspond to physically separate entities. That is, these functional entities may be implemented in the form of an application program, in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0027] The flowcharts shown in the accompanying drawings are for illustrative purposes only and do not necessarily include all contents and operations / steps, nor must they be executed in the order described. For example, some operations / steps may be decomposed, while others may be combined or partially combined. Therefore, the actual execution order may vary depending on the actual situation.

[0028] It should be noted that the term "plurality" used in this application refers to two or more. "And / or" describes the relationship between associated objects, indicating that three possible relationships exist. For example, "A and / or B" can represent: A alone, A and B together, or B alone. The character " / " generally indicates that the associated objects are in an "or" relationship.

[0029] The cooling system is applied to a vehicle, and the cooling system is used to cool the heating elements in the vehicle, such as the engine, battery, motor, etc.; in the embodiment of the present application, the heating element is the engine.

[0030] Combine Figure 1 As shown, Figure 1 This is a schematic diagram of the cooling system structure of an exemplary embodiment of the present application. The cooling system includes an engine cylinder head 1, an engine block 2, an oil cooler 3, an electronic water pump 4, a temperature control module 5, a radiator 6, and an expansion tank 7. The oil cooler 3 is used to controlably lower the oil temperature, the electronic water pump 4 is used to control the coolant flow in the cooling system, the temperature control module 5 is used to control the branch flow and on / off, the radiator 6 is used to control the coolant temperature, and the expansion tank 7 is used to store coolant. The cooling system also includes an exhaust manifold 8, a heater core 9, a first water temperature sensor 10, a second water temperature sensor 11, a third water temperature sensor 12, and a fourth water temperature sensor 13.

[0031] The outlet end of the electronic water pump 4 is connected to the engine cylinder head 1 through the exhaust manifold 8, and the outlet end of the electronic water pump 4 is also connected to the engine cylinder block 2 and the oil cooler 3 respectively; the oil cooler 3 is connected to the heater core 9, and the heater core 9 is used to transfer the heat of the engine coolant to the vehicle, thereby providing a comfortable driving environment; the heater core 9 is connected to the temperature control module 5, the engine cylinder head 1 is connected to the temperature control module 5 and the expansion water tank 7 respectively, the engine cylinder block 2 is connected to the temperature control module 5, the temperature control module 5 is connected to the radiator 6 and the inlet end of the electronic water pump 4 respectively, the radiator 6 is connected to the expansion water tank 7 and the inlet end of the electronic water pump 4 respectively, and the expansion water tank 7 is connected to the inlet end of the electronic water pump 4.

[0032] A first water temperature sensor 10 is disposed between the engine cylinder head 1 and the temperature control module 5. The first water temperature sensor 10 is used to monitor the coolant temperature at the outlet of the engine cylinder head 1. A second water temperature sensor 11 is connected to the engine cylinder block 2. The second water temperature sensor 11 is used to monitor the coolant temperature inside the engine cylinder block 2. A third water temperature sensor 12 is disposed between the electronic water pump 4 and the exhaust manifold 8. The third water temperature sensor 12 is used to monitor the coolant temperature at the inlet of the engine. A fourth water temperature sensor 13 is disposed between the radiator 6 and the electronic water pump 4. The fourth water temperature sensor 13 is used to monitor the coolant temperature expected to enter the engine after being cooled by the radiator 6. In the embodiment of the present application, the engine cylinder head 1 and the engine cylinder block 2 are connected in parallel.

[0033] The temperature control module 5 is an actuator that adjusts the flow rate through a ball valve structure. During the rotation of the ball valve, the size and on-off adjustment of the flow rate of different branches will be realized. In the embodiment of the present application, the temperature control module 5 is used to control the flow size and on-off of the cylinder branch, the small circulation branch, and the radiator branch; the cylinder branch is the connecting pipe between the engine cylinder 2 and the temperature control module 5, the small circulation branch is the connecting pipe between the temperature control module 5 and the electronic water pump 4, and the radiator branch is the connecting pipe between the temperature control module 5 and the radiator 6.

[0034] See also Figure 2 , Figure 2 It is a flow chart of a method for determining a cooling system fault, shown in an exemplary embodiment of the present application.

[0035] Optionally, in this embodiment, the cooling system fault diagnosis method can be applied to electronic devices. The electronic devices include, but are not limited to, tablet computers, personal computers, or vehicle-mounted terminals. In this embodiment, the electronic device can be a vehicle-mounted terminal.

[0036] The vehicle-mounted terminal may include components such as a processor and a memory. The processor may be a CPU (Central Processing Unit), which obtains the detected temperature of the cooling system through a water temperature sensor, and obtains the actual speed of the electronic water pump and the actual rotation angle of the temperature control module; determines the theoretical inlet branch flow rate and the theoretical outlet branch flow rate of the electronic water pump; corrects the theoretical inlet branch flow rate and the theoretical outlet branch flow rate to obtain the actual inlet branch flow rate and the actual outlet branch flow rate; determines the outlet temperature of the expansion tank; and diagnoses a fault in the cooling system based on the outlet temperature of the expansion tank. The memory may be a RAM (Random Access Memory), Flash (Flash memory), etc., and may be used to store a preset three-dimensional table. The three-dimensional table may store the correspondence between the actual speed of the electronic water pump, the actual rotation angle of the temperature control module, and the theoretical inlet branch flow rate; the three-dimensional table may also store the correspondence between the actual speed of the electronic water pump, the actual rotation angle of the temperature control module, and the theoretical outlet branch flow rate; and the three-dimensional table may also store the correspondence between the thermal state representative temperature of the cooling system, the ambient temperature, and the correction coefficient.

[0037] like Figure 2 As shown, in an exemplary embodiment, the method for determining a cooling system fault includes at least steps S210 to S250, which are described in detail as follows:

[0038] Step S210 , obtaining the detected temperature of the cooling system, the actual speed of the electronic water pump, and the actual rotation angle of the temperature control module.

[0039] In an embodiment of the present application, the detected temperature includes the coolant temperature at the outlet end of the engine cylinder head, the coolant temperature inside the engine cylinder block, the coolant temperature at the inlet end of the engine, and the coolant temperature expected to enter the engine after cooling through the radiator.

[0040] The cooling system is provided with a first water temperature sensor, a second water temperature sensor, a third water temperature sensor and a fourth water temperature sensor; the first water temperature sensor is arranged between the engine cylinder head and the temperature control module, and the coolant temperature at the outlet end of the engine cylinder head is monitored by the first water temperature sensor, the second water temperature sensor is connected to the engine cylinder block, and the coolant temperature inside the engine cylinder block is monitored by the second water temperature sensor, the third water temperature sensor is arranged between the electronic water pump and the exhaust manifold, and the coolant temperature at the inlet end of the engine is monitored by the third water temperature sensor, the fourth water temperature sensor is arranged between the radiator and the electronic water pump, and the coolant temperature expected to enter the engine after cooling by the radiator is monitored by the fourth water temperature sensor.

[0041] Optionally, the detection temperature of the cooling system, the actual speed of the electronic water pump and the actual rotation angle of the temperature control module are obtained, including: when it is detected that the vehicle is powered on, initializing a self-test of the cooling system to obtain a self-test result; when the self-test result is normal, obtaining the detection temperature of the cooling system, the actual speed of the electronic water pump and the actual rotation angle of the temperature control module.

[0042] Furthermore, an initial self-test is performed on the cooling system to obtain self-test results, including: testing the electronic water pump, temperature control module, and temperature sensor respectively to obtain electronic water pump test results, temperature control module test results, and temperature sensor test results; if the electronic water pump test results, temperature control module test results, and temperature sensor test results are all normal, the self-test result is determined to be normal. The temperature sensors include a first water temperature sensor, a second water temperature sensor, a third water temperature sensor, and a fourth water temperature sensor.

[0043] Furthermore, the electronic water pump is tested to obtain a test result of the electronic water pump, including: obtaining a test speed of the electronic water pump, and when the test speed reaches a preset self-test speed, obtaining an operating current of the electronic water pump, and performing a table lookup operation based on the test speed to obtain a corresponding dry-run current of the electronic water pump; comparing the operating current with the dry-run current to obtain a comparison result; if the comparison result shows that the operating current is greater than or equal to the dry-run current, determining that the test result of the electronic water pump is in a normal state; and / or if the comparison result shows that the operating current is less than the dry-run current, determining that the test result of the electronic water pump is in an abnormal state, and reporting a fault of the electronic water pump.

[0044] For example, the electronic water pump failure may be reported by sounding a preset alarm, displaying a failure sign on the vehicle dashboard, and the like.

[0045] Furthermore, the temperature control module is tested to obtain a temperature control module test result, including: obtaining a detection angle of the temperature control module, obtaining a first change in the detection angle within a preset time period when the detection angle reaches a preset mechanical dead-point angle, increasing the motor torque of the temperature control module when the first change is less than a preset threshold, obtaining a second change in the detection angle within a preset time period when the motor torque increases to a preset maximum value, obtaining a difference between the detection angle and the preset mechanical dead-point angle when the second change is less than a preset threshold, determining that the temperature control module test result is normal when the difference is less than a preset allowable error, and / or determining that the temperature control module test result is abnormal when the difference is greater than or equal to the preset allowable error, and reporting a temperature control module failure.

[0046] For example, a temperature control module failure may be reported by sounding a preset alarm, displaying a fault sign on the vehicle dashboard, or the like.

[0047] Furthermore, the temperature sensors are tested to obtain temperature sensor test results, including: obtaining the detected temperature of each temperature sensor, and determining that the temperature sensor test result is normal if the detected temperature of each temperature sensor is within a preset range; and / or determining that the temperature sensor test result is abnormal if any temperature sensor's detected temperature is not within the preset range, and reporting a temperature sensor failure.

[0048] For example, a temperature sensor failure may be reported by sounding a preset alarm, displaying a fault sign on a vehicle dashboard, or the like.

[0049] Step S220 , determining a theoretical inlet branch flow rate and a theoretical outlet branch flow rate of the electronic water pump according to the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module.

[0050] Among them, the theoretical inlet branch flow includes the theoretical outlet flow of the radiator, the theoretical flow of the small circulation branch and the theoretical outlet flow of the expansion tank; the theoretical outlet branch flow includes the theoretical flow of the engine cylinder head, the theoretical flow of the engine cylinder block and the theoretical flow of the oil cooler branch.

[0051] For example, in the present application, the theoretical inlet branch flow and the theoretical outlet branch flow corresponding to the actual speed of the electronic water pump and the actual rotation angle of the temperature control module can be found from a preset three-dimensional table by looking up the table.

[0052] Step S230 , respectively correcting the theoretical inlet branch flow rate and the theoretical outlet branch flow rate according to the detected temperature to obtain the actual inlet branch flow rate and the actual outlet branch flow rate.

[0053] Since the parameter relationships in each three-dimensional table are calibrated through tests at normal temperature and pressure, the values ​​obtained by looking up the table are all theoretical values. In the actual calculation process, temperature mainly brings about changes in pressure and viscosity, which has a certain impact on flow rate. Therefore, by correcting the theoretical values ​​found, more accurate actual values ​​can be obtained.

[0054] For example, the found theoretical inlet branch flow rate and theoretical outlet branch flow rate may be corrected according to a preset correction coefficient.

[0055] Step S240: determining the outlet temperature of the expansion water tank according to the actual inlet branch flow rate and the actual outlet branch flow rate.

[0056] It should be understood that the outlet temperature of the expansion tank includes the outlet temperature of the expansion tank in the direction of water flow and the outlet temperature of the expansion tank in the direction of countercurrent flow; the outlet temperature of the expansion tank in the direction of water flow is equal to the weighted temperature of the two inlet flows of the expansion tank; and for the electronic water pump, the inlet flow of the electronic water pump is composed of the small circulation branch, the radiator branch, and the expansion water tank branch, and the inlet temperature of the electronic water pump is obtained by weighting the three branches; the outlet flow of the water pump is composed of the engine cylinder flow, the engine cylinder head flow, and the oil cooler branch flow; the outlet water temperature of the water pump is the coolant temperature at the inlet end of the engine monitored by the third water temperature sensor, so through this relationship, the outlet temperature of the expansion tank in the direction of countercurrent flow can be further obtained.

[0057] Step S250: diagnose a cooling system fault based on the outlet temperature of the expansion water tank.

[0058] It can be understood that the outlet temperature of the expansion tank in the direction of water flow is only related to the upstream heat flow and is not cooled by the radiator; the outlet temperature of the expansion tank in the direction of countercurrent flow is inferred based on the heat dissipation status of the radiator. If there is an internal leak in the cooling system, the temperature control module leaks unexpectedly, and causes heat leakage when the heat flow passes through the radiator, which will cause the temperature value detected by the fourth water temperature sensor to be higher than expected. At this time, inverse calculation based on the temperature value detected by the third water temperature sensor will cause the calculated value of the outlet temperature of the expansion tank in the direction of countercurrent flow to be lower. The outlet temperature of the expansion tank in the direction of water flow is not affected by internal leakage because the downstream information is not used in the evaluation process. At this time, the internal leakage can be evaluated based on the difference between the outlet temperature of the expansion tank in the direction of water flow and the outlet temperature of the expansion tank in the direction of countercurrent flow.

[0059] Since the related art adds a temperature sensor at the radiator outlet and performs fault diagnosis by detecting the vehicle speed and water temperature after the vehicle is started, this method is only applicable to fault diagnosis during the vehicle's warm-up process during cold start, which easily leads to inaccurate fault diagnosis of the cooling system. In the embodiment of the present application, fault diagnosis is performed by the outlet temperature of the expansion tank, and there is no need to add a temperature sensor at the radiator outlet to detect the outlet temperature. Accurate fault diagnosis of the cooling system can be achieved under different vehicle operating conditions, thereby improving the accuracy of fault diagnosis of the cooling system.

[0060] For example, since the outlet temperature of the expansion water tank includes the outlet temperature of the expansion water tank in the direction of water flow and the outlet temperature of the expansion water tank in the direction of countercurrent flow, it is possible to directly determine whether the cooling system has an internal leakage fault based on the temperature difference between the outlet temperature of the expansion water tank in the direction of water flow and the outlet temperature of the expansion water tank in the direction of countercurrent flow; it is also possible to obtain the average value of multiple temperature differences within a preset time period to determine whether the cooling system has an internal leakage fault.

[0061] In some embodiments, the theoretical inlet branch flow and the theoretical outlet branch flow of the electronic water pump are determined based on the actual speed of the electronic water pump and the actual rotation angle of the temperature control module, including: using the actual speed of the electronic water pump and the actual rotation angle of the temperature control module to perform a table lookup operation to obtain the theoretical inlet branch flow and the theoretical outlet branch flow.

[0062] Among them, the theoretical inlet branch flow includes the theoretical outlet flow of the radiator, the theoretical flow of the small circulation branch and the theoretical outlet flow of the expansion tank; the theoretical outlet branch flow includes the theoretical flow of the engine cylinder head, the theoretical flow of the engine cylinder block and the theoretical flow of the oil cooler branch.

[0063] For example, the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a lookup operation in a preset three-dimensional table to obtain the theoretical outlet flow of the radiator.

[0064] For example, the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a lookup operation in a preset three-dimensional table to obtain the theoretical flow rate of the small circulation branch.

[0065] For example, the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a lookup operation in a preset three-dimensional table to obtain the theoretical outlet flow of the expansion water tank.

[0066] For example, the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a lookup operation in a preset three-dimensional table to obtain the theoretical flow rate of the engine cylinder head.

[0067] For example, the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a lookup operation in a preset three-dimensional table to obtain the theoretical flow rate of the engine cylinder.

[0068] For example, the actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a lookup operation in a preset three-dimensional table to obtain the theoretical flow rate of the oil cooler branch.

[0069] In some embodiments, the theoretical inlet branch flow and the theoretical outlet branch flow are corrected according to the detected temperature to obtain the actual inlet branch flow and the actual outlet branch flow, including: summing the theoretical inlet branch flows to obtain the theoretical total inlet flow; and summing the theoretical outlet branch flows to obtain the theoretical total outlet flow; obtaining the proportion of the theoretical inlet branch flow to the theoretical total inlet flow; and obtaining the proportion of the theoretical outlet branch flow to the theoretical total outlet flow; obtaining the thermal state characterization temperature of the cooling system according to the detected temperature and the proportion of the outlet branch flow; determining the correction coefficient according to the thermal state characterization temperature; correcting the theoretical total inlet flow according to the correction coefficient to obtain the actual total inlet flow; and correcting the theoretical total outlet flow according to the correction coefficient to obtain the actual total outlet flow; determining the actual inlet branch flow according to the actual total inlet flow and the proportion of the inlet branch flow, and determining the actual outlet branch flow according to the actual total outlet flow and the proportion of the outlet branch flow.

[0070] Among them, the theoretical inlet branch flow includes the theoretical outlet flow of the radiator, the theoretical flow of the small circulation branch and the theoretical outlet flow of the expansion tank; the theoretical outlet branch flow includes the theoretical flow of the engine cylinder head, the theoretical flow of the engine cylinder block and the theoretical flow of the oil cooler branch.

[0071] For example, the theoretical outlet flow of the radiator, the theoretical flow of the small circulation branch and the theoretical outlet flow of the expansion tank are summed to obtain the theoretical total inlet flow; and the theoretical flow of the engine cylinder head, the theoretical flow of the engine cylinder block and the theoretical flow of the oil cooler branch are summed to obtain the theoretical total outlet flow.

[0072] Furthermore, the inlet branch flow ratio includes the radiator flow ratio, the small circulation flow ratio and the expansion water tank flow ratio; obtaining the inlet branch flow ratio of the theoretical inlet branch flow to the theoretical total inlet flow includes: determining the ratio of the theoretical radiator outlet flow to the theoretical total inlet flow as the radiator flow ratio; determining the ratio of the theoretical small circulation branch flow to the theoretical total inlet flow as the small circulation flow ratio; and determining the ratio of the theoretical expansion water tank outlet flow to the theoretical total inlet flow as the expansion water tank flow ratio.

[0073] Exemplarily, the theoretical total inlet flow is obtained by calculating mf_total1=mf_Rad+mf_Byps+mf_Tank; wherein mf_total1 is the theoretical total inlet flow, mf_Rad is the theoretical outlet flow of the radiator, mf_Byps is the theoretical flow of the small circulation branch, and mf_Tank is the theoretical outlet flow of the expansion tank.

[0074] The radiator flow rate ratio is obtained by calculating mf_Rad_prop = mf_Rad / mf_total1; where mf_Rad_prop is the radiator flow rate ratio, mf_Rad is the theoretical outlet flow of the radiator, and mf_total1 is the theoretical total inlet flow.

[0075] The proportion of small circulation flow is obtained by calculating mf_Byps_prop = mf_Byps / mf_total1; where mf_Byps_prop is the proportion of small circulation flow, mf_Byps is the theoretical flow of the small circulation branch, and mf_total1 is the theoretical total import flow.

[0076] The expansion tank flow rate ratio is obtained by calculating mf_Tank_prop = mf_Tank / mf_total1; where mf_Tank_prop is the expansion tank flow rate ratio, mf_Tank is the theoretical outlet flow of the expansion tank, and mf_total1 is the theoretical total inlet flow.

[0077] Furthermore, the outlet branch flow ratio includes the engine cylinder head flow ratio, the engine cylinder block flow ratio and the oil cooler branch flow ratio; obtaining the outlet branch flow ratio of the theoretical outlet branch flow to the theoretical outlet total flow includes: determining the ratio of the theoretical engine cylinder head flow to the theoretical outlet total flow as the engine cylinder head flow ratio; determining the ratio of the theoretical engine cylinder block flow to the theoretical outlet total flow as the engine cylinder block flow ratio; and determining the ratio of the theoretical oil cooler branch flow to the theoretical outlet total flow as the oil cooler branch flow ratio.

[0078] Exemplarily, the theoretical total outlet flow is obtained by calculating mf_total2=mf_CylHed+mf_CylBlk+mf_OC; wherein mf_total2 is the theoretical total outlet flow, mf_CylHed is the theoretical flow of the engine cylinder head, mf_CylBlk is the theoretical flow of the engine cylinder block, and mf_OC is the theoretical flow of the oil cooler branch.

[0079] The engine cylinder head flow ratio is obtained by calculating mf_CylHed_prop = mf_CylHed / mf_total2; where mf_CylHed_prop is the engine cylinder head flow ratio, mf_CylHed is the theoretical flow of the engine cylinder head, and mf_total2 is the theoretical total outlet flow.

[0080] The engine cylinder flow rate ratio is obtained by calculating mf_CylBlk_prop = mf_CylBlk / mf_total2; where mf_CylBlk_prop is the engine cylinder flow rate ratio, mf_CylBlk is the theoretical flow rate of the engine cylinder, and mf_total2 is the theoretical total outlet flow rate.

[0081] The oil cooler branch flow rate ratio is obtained by calculating mf_OC_prop = mf_OC / mf_total2; where mf_OC_prop is the oil cooler branch flow rate ratio, mf_OC is the theoretical oil cooler branch flow rate, and mf_total2 is the theoretical total outlet flow rate.

[0082] Furthermore, the thermal state characterization temperature of the cooling system is obtained according to the detected temperature and the proportion of the outlet branch flow, including:

[0083] T_overall=T1*mf_CylHed_prop+T2*mf_CylBlk_prop+T3*mf_OC_prop obtains the thermal state characterization temperature of the cooling system; wherein, T_overall is the thermal state characterization temperature of the cooling system, T1 is the coolant temperature at the outlet end of the engine cylinder head monitored by the first water temperature sensor, T2 is the coolant temperature inside the engine cylinder block monitored by the second water temperature sensor, and T3 is the coolant temperature at the inlet end of the engine monitored by the third water temperature sensor; mf_CylHed_prop is the engine cylinder head flow ratio, mf_CylBlk_prop is the engine cylinder block flow ratio, and mf_OC_prop is the oil cooler branch flow ratio.

[0084] In some embodiments, determining the correction coefficient according to the thermal state representative temperature includes: obtaining the ambient temperature; and performing a table lookup operation according to the thermal state representative temperature and the ambient temperature to obtain the correction coefficient.

[0085] By looking up the table based on the thermal state characterization temperature and ambient temperature of the cooling system, a more accurate correction factor can be determined, which in turn facilitates more accurate correction of the theoretical flow value and obtains a more accurate actual flow value.

[0086] Furthermore, the theoretical total import flow is corrected according to the correction coefficient to obtain the actual total import flow, including: multiplying the theoretical total import flow by the correction coefficient to obtain the actual total import flow.

[0087] Exemplarily, the actual total inlet flow is obtained by calculating mf_total1_Act=mf_total1*mf_mod; wherein mf_total1_Act is the actual total inlet flow, mf_total1 is the theoretical total inlet flow, and mf_mod is the correction coefficient.

[0088] Furthermore, the theoretical total outlet flow is corrected according to the correction coefficient to obtain the actual total outlet flow, including: multiplying the theoretical total outlet flow by the correction coefficient to obtain the actual total outlet flow.

[0089] Exemplarily, the actual total inlet flow is obtained by calculating mf_total2_Act=mf_total2*mf_mod; wherein mf_total2_Act is the actual total outlet flow, mf_total2 is the theoretical total outlet flow, and mf_mod is the correction coefficient.

[0090] Furthermore, the actual inlet branch flow is determined based on the actual total inlet flow and the proportion of inlet branch flow, including: multiplying the actual total inlet flow by the radiator flow proportion to obtain the actual radiator outlet flow; multiplying the actual total inlet flow by the small circulation flow proportion to obtain the actual flow of the small circulation branch; multiplying the actual total inlet flow by the expansion water tank flow proportion to obtain the actual outlet flow of the expansion water tank.

[0091] Exemplarily, the actual outlet flow of the radiator is obtained by calculating mf_Rad_Act=mf_total1_Act*mf_Rad_prop; wherein mf_Rad_Act is the actual outlet flow of the radiator, mf_total1_Act is the actual total inlet flow, and mf_Rad_prop is the radiator flow ratio.

[0092] The actual flow of the small circulation branch is obtained by calculating mf_Byps_Act = mf_total1_Act * mf_Byps_prop; where mf_Byps_Act is the actual flow of the small circulation branch, mf_total1_Act is the actual total inlet flow, and mf_Byps_prop is the proportion of the small circulation flow.

[0093] The actual outlet flow of the expansion water tank is obtained by calculating mf_Tank_Act = mf_total1_Act * mf_Tank_prop; where mf_Tank_Act is the actual outlet flow of the expansion water tank, mf_total1_Act is the actual total inlet flow, and mf_Tank_prop is the proportion of the expansion water tank flow.

[0094] Furthermore, the actual outlet branch flow is determined based on the actual total outlet flow and the proportion of the outlet branch flow, including: multiplying the actual total outlet flow by the proportion of the engine cylinder head flow to obtain the actual flow of the engine cylinder head; multiplying the actual total outlet flow by the proportion of the engine cylinder flow to obtain the actual flow of the engine cylinder; multiplying the actual total outlet flow by the proportion of the oil cooler branch flow to obtain the actual flow of the oil cooler branch.

[0095] Exemplarily, the actual flow of the engine cylinder head is obtained by calculating mf_CylHed_Act=mf_total2_Act*mf_CylHed_prop; wherein mf_CylHed_Act is the actual flow of the engine cylinder head, mf_total2_Act is the actual total outlet flow, and mf_CylHed_prop is the proportion of the engine cylinder head flow.

[0096] The actual flow rate of the engine cylinder is obtained by calculating mf_CylBlk_Act = mf_total2_Act * mf_CylBlk_prop; where mf_CylBlk_Act is the actual flow rate of the engine cylinder, mf_total2_Act is the actual total outlet flow rate, and mf_CylBlk_prop is the proportion of the engine cylinder flow rate.

[0097] The actual flow rate of the oil cooler branch is obtained by calculating mf_OC_Act = mf_total2_Act * mf_OC_prop; where mf_OC_Act is the actual flow rate of the oil cooler branch, mf_total2_Act is the actual total outlet flow rate, and mf_OC_prop is the oil cooler branch flow rate percentage.

[0098] In some embodiments, the actual inlet branch flow includes the actual outlet flow of the expansion tank, the actual outlet flow of the radiator and the actual flow of the small circulation branch; the outlet temperature of the expansion tank includes the outlet temperature of the expansion tank in the downstream direction and the outlet temperature of the expansion tank in the countercurrent direction; the outlet temperature of the expansion tank is determined according to the actual inlet branch flow and the actual outlet branch flow, including: determining the inlet flow of the expansion tank according to the actual outlet flow of the expansion tank and a preset overflow ratio; and determining the internal temperature of the temperature control module according to the detected temperature and the actual outlet branch flow; obtaining the flow temperature of the inlet flow of the expansion tank; weighting the flow temperature according to the actual outlet flow of the expansion tank and the inlet flow of the expansion water tank to obtain the outlet temperature of the expansion tank in the downstream direction; and determining the outlet temperature of the expansion tank in the countercurrent direction according to the actual outlet flow of the radiator, the actual flow of the small circulation branch and the internal temperature of the temperature control module.

[0099] It's understandable that the expansion tank actually has two inlets and one outlet, for a total of three branches: two inlet branches and one outlet branch. The inlet branches connect the expansion tank to the engine cylinder head and the radiator, respectively; the outlet branch connects the expansion tank to the electronic water pump. Therefore, the expansion tank inlet flow includes both radiator overflow and engine overflow.

[0100] Furthermore, the expansion tank inlet flow includes the radiator overflow flow and the engine overflow flow; determining the expansion tank inlet flow based on the actual expansion tank outlet flow and a preset overflow ratio includes: obtaining the radiator overflow flow based on the actual expansion tank outlet flow and a preset overflow ratio; and determining the difference between the actual expansion tank outlet flow and the radiator overflow flow as the engine overflow flow.

[0101] Exemplarily, the radiator overflow flow is obtained by calculating mf_Tank_Rad_in_Act=mf_Rad_Act*mf_Rad_gas_coef; wherein mf_Tank_Rad_in_Act is the radiator overflow flow, mf_Rad_Act is the actual outlet flow of the expansion tank, and mf_Rad_gas_coef is the preset overflow ratio.

[0102] Further, the internal temperature of the temperature control module is determined according to the detected temperature and the actual outlet branch flow, including:

[0103] Obtain the internal temperature of the temperature control module; where T_tmmInnr is the internal temperature of the temperature control module, T1 is the coolant temperature at the outlet of the engine cylinder head monitored by the first water temperature sensor, T2 is the coolant temperature inside the engine cylinder block monitored by the second water temperature sensor, T_overall is the thermal state characterizing temperature of the cooling system, mf_CylHed_Act is the actual flow rate of the engine cylinder head, mf_CylBlk_Act is the actual flow rate of the engine cylinder block, and mf_OC_Act is the actual flow rate of the oil cooler branch.

[0104] Furthermore, obtaining the flow temperature of the expansion tank inlet flow includes obtaining the temperature of the radiator overflow flow and the temperature of the engine overflow flow.

[0105] Furthermore, obtaining the temperature of the radiator overflow flow includes: determining the internal temperature of the temperature control module as the temperature of the radiator overflow flow.

[0106] It can be understood that the internal temperature of the temperature control module is the temperature of the coolant flowing into the radiator. The coolant is cooled along the way in the radiator until it drops to the temperature monitored by the fourth water temperature sensor. Therefore, the temperature of the radiator overflow flow is the internal temperature of the temperature control module.

[0107] Furthermore, obtaining the temperature of the engine overflow flow includes determining the temperature of the engine overflow flow based on the detected temperature and preset engine cylinder head design parameters. The detected temperatures include T1, T2, and T3; T1 is the coolant temperature at the outlet of the engine cylinder head as monitored by a first water temperature sensor, T2 is the coolant temperature inside the engine cylinder block as monitored by a second water temperature sensor, and T3 is the coolant temperature at the inlet of the engine as monitored by a third water temperature sensor.

[0108] Furthermore, the engine blow-by gas flow temperature is determined based on the detected temperature and preset engine cylinder head design parameters, including: obtaining the engine blow-by gas flow temperature by calculating T_CylHed_gas = [(T1-T3) / Len-CylHed]*Len-CylHed-gas+T3; where T_CylHed_gas is the engine blow-by gas flow temperature, Len_CylHed is the equivalent length of the engine cylinder head outlet, and Len_CylHed_gas is the equivalent length from the engine cylinder head inlet to the engine cylinder head blow-by gas point. In this embodiment of the present application, the engine blow-by gas point is at the highest point of the engine cylinder head, the cylinder head outlet temperature is T1, and the cylinder head inlet temperature is T3.

[0109] Furthermore, the flow temperature is weighted according to the actual outlet flow of the expansion water tank and the inlet flow of the expansion water tank to obtain the outlet temperature of the expansion water tank in the downstream direction, including: obtaining the outlet temperature of the expansion water tank in the downstream direction by calculating T_Tank_outlet_forw = (mf_Tank_Eng_in_Act*T_CylHed_gas+mf_Tank_Rad_in_Act*T_Rad_gas) / mf_Tank_Act; wherein, T_Tank_outlet_forw is the outlet temperature of the expansion water tank in the downstream direction, mf_Tank_Eng_in_Act is the engine overflow flow, T_CylHed_gas+mf is the temperature of the engine overflow flow, mf_Tank_Rad_in_Act is the radiator overflow flow, T_Rad_gas is the temperature of the radiator overflow flow, and mf_Tank_Act is the actual outlet flow of the expansion water tank.

[0110] Furthermore, the outlet temperature of the expansion tank in the countercurrent direction is determined according to the actual outlet flow of the radiator, the actual flow of the small circulation branch and the internal temperature of the temperature control module, including: obtaining the outlet temperature of the expansion tank in the countercurrent direction by calculating T_Tank_outlet_rev = (mf_total2_Act*T3–T_tmmInner*mf_Byps_Act–T4*mf_Rad_Act) / mf_Tank_Act; wherein, T_Tank_outlet_rev is the outlet temperature of the expansion tank in the countercurrent direction, mf_total2_Act is the actual total outlet flow, T_tmmInner is the internal temperature of the temperature control module, mf_Byps_Act is the actual flow of the small circulation branch, mf_Rad_Act is the actual outlet flow of the radiator, mf_Tank_Act is the actual outlet flow of the expansion tank, and T4 is the coolant temperature expected to enter the engine after cooling by the radiator as monitored by the fourth water temperature sensor.

[0111] In some embodiments, a fault diagnosis of the cooling system is performed based on the outlet temperature of the expansion water tank, including: obtaining multiple temperature differences between the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the reverse direction within a preset time period; obtaining an average temperature difference of the multiple temperature differences; and determining a fault of the cooling system based on the average temperature difference.

[0112] Exemplarily, the temperature difference is obtained by calculating T_delta=T_Tank_outlet_forw-T_Tank_outlet-rev; wherein T-delta is the temperature difference between the expansion water tank outlet temperature in the downstream direction and the expansion water tank outlet temperature in the countercurrent direction, T-Tank-outlet_forw is the expansion water tank outlet temperature in the downstream direction, and T_Tank-outlet_rev is the expansion water tank outlet temperature in the countercurrent direction.

[0113] Further, obtaining the average temperature difference of multiple temperature differences includes: calculating Obtain an average temperature difference; wherein, ave_T-delta is the average temperature difference, sum_T_delta is the sum of multiple temperature differences, n is the total number of temperature differences in a preset time period, sum_T_delta = T_delta(0)+T_delta(1)+T_delta(2)+…T_delta(n), and T_delta(n) is the nth temperature difference in the preset time period.

[0114] In some embodiments, determining a cooling system fault based on the average temperature difference includes: if the average temperature difference is greater than a preset threshold, accumulating a cumulative number of faults; and if the cumulative number of faults reaches a preset number, determining that an internal leakage fault has occurred in the cooling system. The preset number is five.

[0115] For example, when it is detected that the temperature difference average value ave_T_delta is greater than the preset threshold, the internal leakage fault flag lgg_err=1 is confirmed once, and the cumulative fault count err_count is accumulated once. After the cumulative fault count is accumulated, the internal leakage fault flag is reset to lgg_err=0, and then the next cycle judgment is entered; when the cumulative fault count err_count reaches the preset number, it is determined that an internal leakage fault has occurred in the cooling system. In this way, internal leakage diagnosis can be achieved under any working conditions, not limited to the early hot engine state, not limited to vehicle speed and other conditions, and when internal leakage occurs in the engine cooling system, it can be identified in time and the overcooling state of the engine can be confirmed to avoid problems such as excessive emissions, oil dilution, and insufficient warm air.

[0116] See also Figure 3 , Figure 3 This is an exemplary process of correcting the theoretical inlet branch flow rate and the theoretical outlet branch flow rate according to the detected temperature in step S230 to obtain the actual inlet branch flow rate and the actual outlet branch flow rate, which may include steps S310 to S360, as detailed below:

[0117] Step S310 , summing the theoretical inlet branch flows to obtain the theoretical inlet total flow; and summing the theoretical outlet branch flows to obtain the theoretical outlet total flow.

[0118] Step S320, obtaining the proportion of the theoretical inlet branch flow to the theoretical total inlet flow; and obtaining the proportion of the theoretical outlet branch flow to the theoretical total outlet flow.

[0119] Step S330 : obtaining a thermal state representative temperature of the cooling system according to the detected temperature and the flow ratio of the outlet branch.

[0120] Step S340 , performing a table lookup operation according to the thermal state characterizing temperature and the ambient temperature to obtain a correction coefficient.

[0121] Step S350, correcting the theoretical total inlet flow rate according to the correction coefficient to obtain the actual total inlet flow rate; and correcting the theoretical total outlet flow rate according to the correction coefficient to obtain the actual total outlet flow rate.

[0122] Step S360: determining the actual inlet branch flow rate according to the actual total inlet flow rate and the proportion of the inlet branch flow rate, and determining the actual outlet branch flow rate according to the actual total outlet flow rate and the proportion of the outlet branch flow rate.

[0123] In the embodiments of the present application, since the parameter relationships in each table are calibrated through tests at normal temperature and pressure, the values ​​obtained by looking up the table are all theoretical values. In the actual calculation process, temperature mainly brings about changes in pressure and viscosity, which has a certain impact on the flow rate, so temperature change correction should also be considered; by correcting the collected theoretical inlet branch flow and theoretical outlet branch flow, more accurate actual flow values ​​can be obtained, which facilitates more accurate fault identification of the cooling system.

[0124] See also Figure 4 , Figure 4 This is an exemplary process of determining a cooling system fault based on the outlet temperature of the expansion water tank in step S250, which may include steps S410 to S440, as detailed below:

[0125] The outlet temperature of the expansion water tank includes the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the countercurrent direction.

[0126] Step S410 , obtaining a plurality of temperature differences between the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the reverse direction within a preset time period.

[0127] Step S420: Obtain an average temperature difference of multiple temperature differences.

[0128] Step S430: When the average temperature difference is greater than a preset threshold, the cumulative number of faults is accumulated.

[0129] Step S440: When the accumulated number of failures reaches a preset number, it is determined that an internal leakage failure occurs in the cooling system.

[0130] As described above, by obtaining the average temperature difference of multiple temperature differences within a preset time period, the probability of misdiagnosis of faults can be reduced, thereby improving the accuracy of cooling system fault diagnosis. In addition, since the related art adds a temperature sensor at the radiator outlet and performs fault diagnosis by detecting the vehicle speed and water temperature after startup, this method is only applicable to fault diagnosis during the vehicle's warm-up process during a cold start, which can easily lead to inaccurate cooling system fault diagnosis. In the embodiment of the present application, fault diagnosis is performed by detecting the outlet temperature of the expansion tank, eliminating the need for adding a temperature sensor at the radiator outlet to detect the outlet temperature. This allows accurate cooling system fault diagnosis under different vehicle operating conditions, further improving the accuracy of cooling system fault diagnosis.

[0131] Combine Figure 5 As shown, another exemplary embodiment of the present application also provides a device for cooling system fault judgment, the cooling system is applied to a vehicle, the cooling system includes an engine cylinder head, an engine block, an oil cooler, an electronic water pump, a temperature control module, a radiator and an expansion water tank; the oil cooler is used to controllably reduce the oil temperature, the electronic water pump is used to controllably adjust the coolant flow in the cooling system, the temperature control module is used to controllably adjust the branch flow and on-off, the radiator is used to controllably reduce the coolant temperature, and the expansion water tank is used to store the coolant; the device includes: an acquisition module 510, a first determination module 520, a correction module 530, a second determination module 540 and a judgment module 550. The acquisition module 510 is configured to acquire the detected temperature of the cooling system, the actual speed of the electronic water pump and the actual rotation angle of the temperature control module; the first determination module 520 is configured to determine the theoretical inlet branch flow and the theoretical outlet branch flow of the electronic water pump based on the actual speed of the electronic water pump and the actual rotation angle of the temperature control module; the correction module 530 is configured to correct the theoretical inlet branch flow and the theoretical outlet branch flow according to the detected temperature, and obtain the actual inlet branch flow and the actual outlet branch flow; the second determination module 540 is configured to determine the outlet temperature of the expansion water tank based on the actual inlet branch flow and the actual outlet branch flow; the judgment module 550 is configured to perform fault judgment on the cooling system according to the outlet temperature of the expansion water tank.

[0132] Furthermore, the acquisition module 510 is configured to obtain the detection temperature of the cooling system, the actual speed of the electronic water pump and the actual rotation angle of the temperature control module in the following manner: when it is detected that the vehicle is powered on, the cooling system is initialized for self-test and the self-test result is obtained; when the self-test result is normal, the detection temperature of the cooling system, the actual speed of the electronic water pump and the actual rotation angle of the temperature control module are obtained.

[0133] Furthermore, the first determination module 520 is configured to determine the theoretical inlet branch flow and the theoretical outlet branch flow of the electronic water pump based on the actual speed of the electronic water pump and the actual rotation angle of the temperature control module in the following manner: using the actual speed of the electronic water pump and the actual rotation angle of the temperature control module to perform a table lookup operation to obtain the theoretical inlet branch flow and the theoretical outlet branch flow.

[0134] Furthermore, the correction module 530 is configured to correct the theoretical inlet branch flow and the theoretical outlet branch flow according to the detected temperature in the following manner to obtain the actual inlet branch flow and the actual outlet branch flow: sum the theoretical inlet branch flows to obtain the theoretical total inlet flow; and sum the theoretical outlet branch flows to obtain the theoretical total outlet flow; obtain the proportion of the theoretical inlet branch flow to the theoretical total inlet flow; and obtain the proportion of the theoretical outlet branch flow to the theoretical total outlet flow; obtain the thermal state characterization temperature of the cooling system according to the detected temperature and the proportion of the outlet branch flow; determine the correction coefficient according to the thermal state characterization temperature; correct the theoretical total inlet flow according to the correction coefficient to obtain the actual total inlet flow; and correct the theoretical total outlet flow according to the correction coefficient to obtain the actual total outlet flow; determine the actual inlet branch flow according to the actual total inlet flow and the proportion of the inlet branch flow, and determine the actual outlet branch flow according to the actual total outlet flow and the proportion of the outlet branch flow.

[0135] Furthermore, the correction module 530 is configured to determine the correction coefficient according to the thermal state representative temperature in the following manner: obtaining the ambient temperature; performing a table lookup operation according to the thermal state representative temperature and the ambient temperature to obtain the correction coefficient.

[0136] Furthermore, the actual inlet branch flow includes the actual outlet flow of the expansion tank, the actual outlet flow of the radiator and the actual flow of the small circulation branch; the outlet temperature of the expansion tank includes the outlet temperature of the expansion tank in the downstream direction and the outlet temperature of the expansion tank in the upstream direction; the second determination module 540 is configured to determine the outlet temperature of the expansion tank according to the actual inlet branch flow and the actual outlet branch flow in the following manner: determine the inlet flow of the expansion tank according to the actual outlet flow of the expansion tank and the preset overflow ratio; and determine the internal temperature of the temperature control module according to the detected temperature and the actual outlet branch flow; obtain the flow temperature of the inlet flow of the expansion tank; perform weighted processing on the flow temperature according to the actual outlet flow of the expansion tank and the inlet flow of the expansion water tank to obtain the outlet temperature of the expansion tank in the downstream direction; and determine the outlet temperature of the expansion tank in the upstream direction according to the actual outlet flow of the radiator, the actual flow of the small circulation branch and the internal temperature of the temperature control module.

[0137] Furthermore, the judgment module 550 is configured to perform a fault judgment on the cooling system based on the outlet temperature of the expansion water tank in the following manner: obtaining multiple temperature differences between the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the upstream direction within a preset time period; obtaining an average temperature difference of the multiple temperature differences; and performing a fault judgment on the cooling system based on the average temperature difference.

[0138] Furthermore, the judgment module 550 is configured to judge the fault of the cooling system based on the average temperature difference in the following manner: when the average temperature difference is greater than a preset threshold, the cumulative number of faults is accumulated once; when the cumulative number of faults reaches a preset number, it is determined that an internal leakage fault has occurred in the cooling system.

[0139] It should be noted that the cooling system fault diagnosis device provided in the above embodiment and the cooling system fault diagnosis method provided in the above embodiment are based on the same concept. The specific manner in which each module and unit performs operations has been described in detail in the method embodiment and will not be repeated here. In actual applications, the cooling system fault diagnosis device provided in the above embodiment can distribute the above functions to different functional modules as needed, that is, divide the internal structure of the device into different functional modules to complete all or part of the functions described above, and this is not limited here.

[0140] An embodiment of the present application also provides an electronic device, comprising: one or more processors; and a memory for storing one or more programs. When the one or more programs are executed by the one or more processors, the electronic device implements the method for determining a cooling system fault provided in the above-mentioned embodiments.

[0141] Another aspect of the present application provides a computer-readable storage medium having a computer program stored thereon, which, when executed by a processor, implements the network device traffic diversion control method described above. The computer-readable storage medium may be included in the electronic device described in the above embodiments, or may exist independently and not be incorporated into the electronic device.

[0142] It should be noted that the computer-readable storage medium shown in the embodiments of the present application may include, but is not limited to: an electrical connection having one or more wires, a portable computer disk, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM), a flash memory, an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination thereof. The computer program contained in the computer-readable storage medium may be transmitted using any suitable medium, including, but not limited to, wireless, wired, etc., or any suitable combination thereof.

[0143] The above content is only a preferred exemplary embodiment of the present application and is not intended to limit the implementation scheme of the present application. Ordinary technicians in this field can easily make corresponding changes or modifications based on the main ideas and spirit of the present application. Therefore, the scope of protection of the present application shall be based on the scope of protection required by the claims.

Claims

1. A method for determining a cooling system fault, characterized in that: The cooling system is applied to a vehicle, and includes an electronic water pump, a temperature control module, and an expansion water tank; the electronic water pump is used to control and adjust the flow rate of coolant in the cooling system; the temperature control module is used to control and adjust the flow rate and on / off of each branch of the electronic water pump; and the expansion water tank is used to store coolant; the method includes: Obtaining the detected temperature of the cooling system, the actual speed of the electronic water pump, and the actual rotation angle of the temperature control module; Determining a theoretical inlet branch flow rate and a theoretical outlet branch flow rate of the electronic water pump according to an actual rotation speed of the electronic water pump and an actual rotation angle of the temperature control module; Correcting the theoretical inlet branch flow and the theoretical outlet branch flow according to the detected temperature to obtain an actual inlet branch flow and an actual outlet branch flow; determining an outlet temperature of the expansion water tank according to the actual inlet branch flow rate and the actual outlet branch flow rate; A fault diagnosis is performed on the cooling system according to the outlet temperature of the expansion water tank.

2. The method according to claim 1, characterized in that Determining a theoretical inlet branch flow rate and a theoretical outlet branch flow rate of the electronic water pump according to an actual rotation speed of the electronic water pump and an actual rotation angle of the temperature control module includes: The actual rotation speed of the electronic water pump and the actual rotation angle of the temperature control module are used to perform a table lookup operation to obtain the theoretical inlet branch flow rate and the theoretical outlet branch flow rate.

3. The method according to claim 1, characterized in that Correcting the theoretical inlet branch flow and the theoretical outlet branch flow according to the detected temperature to obtain an actual inlet branch flow and an actual outlet branch flow, including: The theoretical inlet branch flow rates are summed to obtain a theoretical total inlet flow rate; and the theoretical outlet branch flow rates are summed to obtain a theoretical total outlet flow rate; Obtaining the proportion of the theoretical inlet branch flow to the theoretical total inlet flow; and obtaining the proportion of the theoretical outlet branch flow to the theoretical total outlet flow; Obtaining a thermal state representative temperature of the cooling system according to the detected temperature and the flow ratio of the outlet branch; determining a correction factor according to the thermal state characterizing temperature; Correcting the theoretical total inlet flow rate according to the correction coefficient to obtain the actual total inlet flow rate; and correcting the theoretical total outlet flow rate according to the correction coefficient to obtain the actual total outlet flow rate; The actual inlet branch flow is determined according to the actual total inlet flow and the proportion of the inlet branch flow, and the actual outlet branch flow is determined according to the actual total outlet flow and the proportion of the outlet branch flow.

4. The method according to claim 3, characterized in that Determining a correction coefficient according to the thermal state characterization temperature includes: Get the ambient temperature; A table lookup operation is performed according to the thermal state characterizing temperature and the ambient temperature to obtain the correction coefficient.

5. The method according to claim 1, wherein The actual inlet branch flow rate includes the actual outlet flow rate of the expansion water tank, the actual outlet flow rate of the radiator and the actual flow rate of the small circulation branch; the outlet temperature of the expansion water tank includes the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the reverse direction; Determining the outlet temperature of the expansion water tank according to the actual inlet branch flow rate and the actual outlet branch flow rate includes: Determining the inlet flow rate of the expansion water tank according to the actual outlet flow rate of the expansion water tank and a preset overflow ratio; and determining the internal temperature of the temperature control module according to the detected temperature and the actual outlet branch flow; Obtaining the flow rate temperature of the expansion water tank inlet flow; The flow temperature is weighted according to the actual outlet flow of the expansion water tank and the inlet flow of the expansion water tank to obtain the outlet temperature of the expansion water tank in the downstream direction; and the outlet temperature of the expansion water tank in the countercurrent direction is determined according to the actual outlet flow of the radiator, the actual flow of the small circulation branch and the internal temperature of the temperature control module.

6. The method according to claim 5, characterized in that The cooling system is subjected to fault diagnosis according to the outlet temperature of the expansion water tank, including: Acquire multiple temperature differences between the outlet temperature of the expansion water tank in the downstream direction and the outlet temperature of the expansion water tank in the reverse direction within a preset time period; Obtaining an average temperature difference of the multiple temperature differences; A fault judgment is performed on the cooling system according to the average value of the temperature difference.

7. The method according to claim 6, characterized in that Performing fault judgment on the cooling system according to the average value of the temperature difference includes: When the average value of the temperature difference is greater than a preset threshold, the cumulative number of faults is accumulated once; When the accumulated number of failures reaches a preset number, it is determined that an internal leakage failure occurs in the cooling system.

8. A device for determining a cooling system fault, characterized in that: The cooling system is applied to a vehicle, and includes an electronic water pump, a temperature control module, and an expansion water tank; the electronic water pump is used to control and adjust the coolant flow in the cooling system; the temperature control module is used to control and adjust the flow and on / off of each branch of the electronic water pump; and the expansion water tank is used to store the coolant; the device includes: an acquisition module configured to acquire a detected temperature of the cooling system, an actual speed of the electronic water pump, and an actual rotation angle of the temperature control module; a first determining module, configured to determine a theoretical inlet branch flow rate and a theoretical outlet branch flow rate of the electronic water pump according to an actual rotation speed of the electronic water pump and an actual rotation angle of the temperature control module; a correction module configured to correct the theoretical inlet branch flow rate and the theoretical outlet branch flow rate according to the detected temperature to obtain an actual inlet branch flow rate and an actual outlet branch flow rate; a second determining module, configured to determine the outlet temperature of the expansion water tank according to the actual inlet branch flow rate and the actual outlet branch flow rate; The judgment module is configured to perform fault judgment on the cooling system according to the outlet temperature of the expansion water tank.

9. An electronic device, characterized in that: include: one or more processors; A storage device for storing one or more programs, which, when executed by the one or more processors, enables the electronic device to implement the method for determining a cooling system fault as described in any one of claims 1 to 7.

10. A computer-readable storage medium having a computer program stored thereon, characterized in that: When the program is executed by a processor, the method for determining a cooling system fault according to any one of claims 1 to 7 is implemented.

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