A thermostat diagnosis method, diagnosis device, storage medium, and controller

Abstract

The present application belongs to the technical field of automobile engineering, and particularly relates to a thermostat diagnosis method, a diagnosis device, a storage medium and a controller. By introducing a delay filtering process, the influence of frequent start-stop working conditions or speed fluctuation working conditions on the temperature difference method can be avoided in the thermostat fault diagnosis, and the detection rate and reliability are improved. By reasonably selecting parameters, data with large amplitude and fluctuation in the characteristic physical quantity information can be eliminated, which is more conducive to the calibration of thermostat parameters. In addition, the method can effectively identify the running state of the engine, and only related diagnosis is performed in the stable speed working interval, so that the reliability of the diagnosis is further improved.

Description

Technical Field

[0001] This invention belongs to the field of automotive engineering technology, and in particular relates to a thermostat diagnostic method, diagnostic device, storage medium and controller. Background Technology

[0002] The current system's diagnostics of the thermostat focus on faults where it is stuck in the maximum open position. In this faulty state, the thermostat cannot reset when needed, leading to excessively low coolant temperature and affecting the engine's fuel economy.

[0003] The above-mentioned faults are quite common and are usually attributed to a broken or malfunctioning reset spring or excessive scale buildup, which manifests as the thermostat failing to fully reset or getting stuck in the maximum open position.

[0004] The relevant technology is based on dual water temperature sensors to diagnose the above-mentioned faults in the thermostat. Two water temperature sensors are required for diagnosis. The first water temperature sensor ECT1 is installed in the small circulation water circuit to obtain the first engine main water temperature T1, and the second water temperature sensor ECT2 is installed in the large circulation water circuit to obtain the second control zone water temperature T2.

[0005] like Figure 1 As shown in the left figure, under fault-free conditions, the thermostat is normally closed, the coolant temperature in the small circulation loop rises, while the coolant temperature in the large circulation loop remains unchanged (there may be a slight temperature rise due to radiator heating and thermostat leakage); when the small circulation coolant temperature reaches the thermostat opening temperature, the thermostat opens, and the coolant in the large circulation loop heats up rapidly; before the thermostat opens, because the coolant flows through the small circulation loop, the temperature difference between T1 and T2 is relatively large. When the maximum temperature difference is greater than or equal to the threshold, it can be determined that there is no fault.

[0006] like Figure 1 As shown in the right figure, in the event of a malfunction, the thermostat is stuck in the fully open position, shutting off the small circulation pipe and allowing the coolant to directly enter the large circulation system. At this time, the second water temperature sensor ECT2 measures the temperature of the large circulation coolant, which is the water temperature T2 in the second control zone. Since T2 rises rapidly, the temperatures of T1 and T2 are close, meaning the temperature difference is small, thus it can be determined that the thermostat is stuck in the fully open position.

[0007] The above diagnostic method can be called the temperature difference method. Its problems and defects are: for some models, especially hybrid models, it is difficult to effectively identify the relevant fault when the thermostat is stuck and always open; in addition, if a high fault threshold is set, the probability of false alarms will be high. Summary of the Invention

[0008] This invention discloses a thermostat diagnostic method, including a first preprocessing step, a second delayed filtering step, and a third comprehensive judgment step; wherein, the first preprocessing step acquires characteristic physical quantity information and detects diagnostic condition information; the characteristic physical quantity information includes a first engine main water temperature T1 and a second control zone water temperature T2, and the diagnostic condition information includes a first diagnostic initiation condition, a second diagnostic stabilization condition, and a third diagnostic completion condition.

[0009] Specifically, if the first diagnostic initiation condition is met, the process proceeds to the second delayed filtering step. The second delayed filtering step continuously detects or scans the second diagnostic stabilization condition. If the second stabilization condition is met, the process proceeds to the third comprehensive judgment step.

[0010] The third comprehensive judgment step involves cyclically detecting or scanning the third diagnostic completion condition. If the third diagnostic completion condition is met, the third working state of the thermostat is determined by comparing the relationship between the characteristic physical quantity and / or the third preset statistical quantity of the characteristic physical quantity and the preset judgment criterion. The third working state includes the third fault state and the third normal state.

[0011] Further, the first preprocessing step obtains the water temperature difference deltaT between the first engine main water temperature T1 and the second control zone water temperature T2; the second delayed filtration step detects engine operating condition information, which includes engine running duration, engine speed, engine speed fluctuation value and / or engine speed acceleration; wherein, the engine running duration is the length of time the engine has been running continuously since it started.

[0012] Specifically, the third comprehensive judgment step can only be entered when the engine running duration is greater than or equal to the delay time threshold t1 and the speed condition is met at the same time; the speed condition includes the first amplitude condition and / or the second fluctuation condition; the first amplitude condition is met when the engine speed is greater than the preset speed threshold n; the second fluctuation condition is met when the engine acceleration is less than the preset acceleration threshold or the change in engine speed within the preset time range is less than the fluctuation threshold X.

[0013] The third preset statistic can be the temperature difference peak value deltaTmax, which is the maximum value of the water temperature difference deltaT at different times; the first diagnostic initiation condition includes the intake flow integral, and the second delayed filtering step and / or the third comprehensive judgment step can only be entered when the intake flow integral is greater than or equal to the preset first flow integral threshold; the third diagnostic completion condition includes at least one of the following conditions: the intake flow integral is greater than or equal to the third flow integral threshold, the first engine main water temperature T1 is greater than or equal to the first main temperature threshold, the first engine main water temperature T1 is greater than or equal to the second main temperature threshold and the water temperature difference deltaT is less than or equal to the third temperature difference threshold.

[0014] Furthermore, the first diagnostic initiation condition also includes an ambient temperature condition, which is only satisfied when the ambient temperature of the engine is greater than or equal to a first ambient temperature threshold. The first flow integral threshold is 100 grams, the first main temperature threshold is 76 degrees Celsius, the second main temperature threshold is 70 degrees Celsius, and the first ambient temperature threshold is -7 degrees Celsius.

[0015] Specifically, the engine main water temperature T1 can be collected from the engine coolant outlet pipe body, and the second control zone water temperature T2 can be collected from the radiator water tank outlet side water tank body; the engine can be used in hybrid vehicles or vehicles with automatic start-stop control; the temperature difference peak value deltaTmax is refreshed or updated only when the second diagnostic stability enhancement condition is met, otherwise the temperature difference peak value deltaTmax continues to use the value of the previous sampling time or the value obtained from the first sampling.

[0016] If the conditions for completing the third diagnosis meet the preset requirements, the third working state is output; the third preset statistic is the statistic of the water temperature difference deltaT or the statistic constructed by the area method in the thermostat diagnosis; if the temperature difference peak deltaTmax is greater than or equal to the fault threshold, the third working state is the third normal state, otherwise the third working state is the third fault state.

[0017] Corresponding to the method of the present invention, a diagnostic device is also disclosed, including a first preprocessing unit, a second delay filtering unit, and a third comprehensive judgment unit; wherein, the first preprocessing unit acquires characteristic physical quantity information and detects diagnostic condition information; the characteristic physical quantity information includes a first engine main water temperature T1 and a second control zone water temperature T2, and the diagnostic condition information includes a first diagnostic initiation condition, a second diagnostic stabilization condition, and a third diagnostic completion condition; if the first diagnostic initiation condition is met, the second delay filtering unit is invoked or started; the second delay filtering unit cyclically detects or scans the second diagnostic stabilization condition, and if the second stabilization condition is met, the third comprehensive judgment unit is invoked or started.

[0018] The third comprehensive judgment unit cyclically detects or scans the third diagnostic completion condition. If the third diagnostic completion condition is met, it compares the characteristic physical quantity and / or the relationship between the third preset statistical quantity of the characteristic physical quantity and the preset judgment criterion to determine the third working state of the thermostat. The third working state includes the third fault state and the third normal state.

[0019] The first preprocessing unit acquires the temperature difference deltaT between the main engine water temperature T1 and the second control zone water temperature T2; the second delayed filtration unit detects engine operating information, including engine running duration, engine speed, engine speed fluctuation value and / or engine speed acceleration; the engine running duration is the length of time the engine has been running continuously since it started.

[0020] Specifically, the third comprehensive judgment unit can only be invoked or started when the engine running duration is greater than or equal to the delay time threshold t1 and the speed condition is met at the same time; the speed condition includes the first amplitude condition and / or the second fluctuation condition; the first amplitude condition is met when the engine speed is greater than the preset speed threshold n; the second fluctuation condition is met when the engine acceleration is less than the preset acceleration threshold or the change in engine speed within the preset time range is less than the fluctuation threshold X.

[0021] Among them: the third preset statistical quantity includes the temperature difference peak value deltaTmax, which is the maximum value of the water temperature difference deltaT at different times; the first diagnostic initiation condition includes the intake flow integral, and the second delay filter unit and / or the third comprehensive judgment unit can only be called or started when the intake flow integral is greater than or equal to the preset first flow integral threshold; the third diagnostic completion condition includes at least one of the following conditions: the intake flow integral is greater than or equal to the third flow integral threshold, the first engine main water temperature T1 is greater than or equal to the first main temperature threshold, the first engine main water temperature T1 is greater than or equal to the second main temperature threshold and the water temperature difference deltaT is less than or equal to the third temperature difference threshold.

[0022] Furthermore, the first diagnostic initiation condition may also include an ambient temperature condition, which is only satisfied when the ambient temperature of the engine is greater than or equal to a first ambient temperature threshold.

[0023] Specifically, the first flow integral threshold can be selected as 100 grams, the first main temperature threshold can be selected as 76 degrees Celsius, the second main temperature threshold can be selected as 70 degrees Celsius, and the first ambient temperature threshold is -7 degrees Celsius.

[0024] Wherein: the engine main water temperature T1 can be collected from the engine coolant outlet pipe body, and the second control area water temperature T2 can be collected from the radiator water tank outlet side water tank body; the engine can be used in hybrid vehicles or vehicles with automatic start-stop control; the temperature difference peak value deltaTmax is refreshed or updated only when the second diagnostic stability enhancement condition is met; otherwise, the temperature difference peak value deltaTmax continues to use the value of the previous sampling time or the value obtained from the first sampling.

[0025] Furthermore: if the conditions for completing the third diagnosis meet the preset requirements, the third working state is output; the third preset statistic can be the statistic of water temperature difference deltaT or the statistic constructed using the area method in thermostat diagnosis; if the peak temperature difference deltaTmax is greater than or equal to the fault threshold, the third working state is the third normal state, otherwise the third working state is the third fault state.

[0026] Corresponding to the method described above, the present invention also discloses a computer storage medium, including a storage medium body for storing a computer program; the computer program, when executed by a microprocessor, implements any of the thermostat diagnostic methods described above; similarly, its controller includes any of the diagnostic devices described above; and / or any of the computer storage media.

[0027] Specifically, the method of the present invention can reduce false alarms or missed alarms when diagnosing thermostats in hybrid vehicles or vehicles with start-stop function; it can also make the thermostats in faulty and normal states more distinguishable, thus improving the reliability of diagnosis.

[0028] It should be noted that the terms "first," "second," and similar terms used in this article are merely for describing the constituent elements of the technical solution and do not constitute a limitation on the technical solution, nor should they be interpreted as an indication or implication of the importance of the corresponding elements; elements with terms such as "first," "second," or similar terms indicate that at least one of the elements is included in the corresponding technical solution. Attached Figure Description

[0029] To more clearly illustrate the technical solution of the present invention and facilitate a further understanding of its technical effects, features, and objectives, the present invention will be described in detail below with reference to the accompanying drawings. The drawings constitute an essential part of the specification and are used together with Embodiment 1 of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation on the present invention.

[0030] The same reference numerals in the attached diagrams represent the same parts, specifically: Figure 1 This is a schematic diagram illustrating the diagnostic principle of thermostats based on temperature difference in related technologies.

[0031] Figure 2 This is a schematic diagram of the diagnostic process for thermostats using the temperature difference method in related technologies.

[0032] Figure 3 This is a schematic diagram of the diagnostic process in an embodiment of the method of the present invention.

[0033] Figure 4 This is the test curve for the core parameter curve in an embodiment of the present invention.

[0034] Figure 5 This is a schematic diagram of the process of an embodiment of the method of the present invention.

[0035] Figure 6 This is a schematic diagram of the structural composition of an embodiment of the diagnostic device of the present invention.

[0036] Figure 7 This is a schematic diagram of the layout structure of an embodiment of the product of the present invention. Figure 1 .

[0037] Figure 8 This is a schematic diagram of the layout structure of an embodiment of the product of the present invention. Figure 2 .

[0038] Figure 9 This is a schematic diagram of the layout structure of an embodiment of the product of the present invention. Figure 3 .

[0039] in: 010 - Diagnostic criteria information; 011 - Conditions for initiating the first diagnosis; 022 - Second diagnostic stabilization condition; 033 - Third diagnostic completion conditions; 100 - First preprocessing step; 101 - First Condition Set; 111 - Steps for obtaining temperature difference; 200 - Second delayed filtering step; 210 - Delay time threshold t1; 220 - Speed ​​condition; 300 - Third Comprehensive Judgment Step; 301 - Third Condition Set; 313 - Steps for updating peak temperature difference; 333 - Peak Temperature Difference Maintenance Steps; 345 - Third working state; 355 - Third preset statistic; 366 - Third Normal State; 399 - Third fault condition; 501 - Delay stage t1; 502 - Effective temperature difference stage t2; 503 - Speed ​​drop phase t3; 600 - Characteristic physical quantity information; 601 - First engine main coolant temperature T1; 602 - Water temperature T2 in the second control zone; 612 - Water temperature difference deltaT; 666 - Engine speed; 699 - Peak temperature difference deltaTmax; 700 - Diagnostic device; 710 - First Preprocessing Unit; 711 - Radiator water tank outlet side water tank body; 712 - Engine coolant outlet pipe body; 720 - Second Delay Filtering Unit; 730 - Third Comprehensive Judgment Unit; 900 - Vehicles; 901 - Controller; 903 - Computer storage media. Detailed Implementation

[0040] The present invention will be further described in detail below with reference to the accompanying drawings and embodiments. Of course, the specific embodiments described below are merely illustrative of the technical solutions of the present invention, and not intended to limit the invention. Furthermore, the parts described in the embodiments or drawings are merely illustrative examples of relevant parts of the present invention, and not the entirety of the invention.

[0041] like Figure 1 , Figure 3 , Figure 5 The thermostat diagnostic method shown includes a first preprocessing step 100, a second delayed filtering step 200, and a third comprehensive judgment step 300; wherein, the first preprocessing step 100 acquires characteristic physical quantity information 600 and detects diagnostic condition information 010; the characteristic physical quantity information 600 includes the first engine main water temperature T1 and the second control zone water temperature T2, and the diagnostic condition information 010 includes the first diagnostic initiation condition 011, the second diagnostic stabilization condition 022, and the third diagnostic completion condition 033.

[0042] Specifically, if the first diagnostic initiation condition 011 is met, the process proceeds to the second delayed filtering step 200; the second delayed filtering step 200 continuously detects or scans the second diagnostic stabilization condition 022; if the second stabilization condition 022 is met, the process proceeds to the third comprehensive judgment step 300.

[0043] Further, the third comprehensive judgment step 300 cyclically detects or scans the third diagnostic completion condition 033. If the third diagnostic completion condition 033 is met, the relationship between the characteristic physical quantity 600 and / or the third preset statistical quantity 355 of the characteristic physical quantity 600 and the preset judgment criterion is compared to determine the third working state 345 of the thermostat. The third working state 345 includes the third fault state 399 and the third normal state 366.

[0044] The first preprocessing step 100 obtains the water temperature difference deltaT612 between the first engine main water temperature T1 and the second control zone water temperature T2; the second delayed filtering step 200 detects engine operating information, which includes engine running duration, engine speed 666, engine speed fluctuation value and / or engine speed acceleration; the engine running duration is the length of time the engine has been running continuously since it started.

[0045] Specifically, the third comprehensive judgment step 300 can only be entered when the engine running duration is greater than or equal to the delay time threshold t1 and the speed condition 220 is met at the same time; the speed condition 220 includes a first amplitude condition and / or a second fluctuation condition; the first amplitude condition is met when the engine speed 666 is greater than the preset speed threshold n; the second fluctuation condition is met when the engine acceleration is less than the preset acceleration threshold or the change in engine speed 666 within the preset time range is less than the fluctuation threshold X.

[0046] Among them, the third preset statistic 355 can be the temperature difference peak value deltaTmax699, which is the maximum value of the water temperature difference deltaT612 at different times; the first diagnosis initiation condition 011 includes the intake flow integral, and the second delay filtering step 200 and / or the third comprehensive judgment step 300 can only be entered when the intake flow integral is greater than or equal to the preset first flow integral threshold; the third diagnosis completion condition 033 includes at least one of the following conditions: the intake flow integral is greater than or equal to the third flow integral threshold, the first engine main water temperature T1 is greater than or equal to the first main temperature threshold, the first engine main water temperature T1 is greater than or equal to the second main temperature threshold and the water temperature difference deltaT612 is less than or equal to the third temperature difference threshold.

[0047] Specifically, the first diagnostic initiation condition 011 may also include an ambient temperature condition, which is satisfied only when the ambient temperature of the engine is greater than or equal to a first ambient temperature threshold. Its first flow integral threshold can be selected as 100 grams, its first main temperature threshold can be selected as 76 degrees Celsius, its second main temperature threshold is 70 degrees Celsius, and its first ambient temperature threshold is -7 degrees Celsius.

[0048] Among them, the engine main water temperature T1 can be collected from the engine coolant outlet pipe body 712, and the second control area water temperature T2 is collected from the radiator water tank outlet side water tank body; the engine is used in hybrid vehicles or vehicles with automatic start-stop control 900; the temperature difference peak value deltaTmax699 is refreshed or updated only when the second diagnostic stability enhancement condition 022 is met, otherwise the temperature difference peak value deltaTmax699 continues to use the value of the previous sampling time or the value obtained from the first sampling.

[0049] Specifically, if the third diagnostic completion condition 033 meets the preset requirements, the third working state 345 is output; the third preset statistic 355 can be the statistic of water temperature difference deltaT612 or the statistic constructed using the area method in thermostat diagnosis; if the temperature difference peak deltaTmax699 is greater than or equal to the fault threshold, the third working state 345 is the third normal state 366, otherwise the third working state 345 is the third fault state 399.

[0050] On the other hand, embodiments of the present invention also disclose, as Figure 6 and Figures 7 to 9 The diagnostic device 700 shown includes a first preprocessing unit 710, a second delay filtering unit 720, and a third comprehensive judgment unit 730; wherein, the first preprocessing unit 710 acquires characteristic physical quantity information 600 and detects diagnostic condition information 010; the characteristic physical quantity information 600 includes the first engine main water temperature T1 and the second control zone water temperature T2, and the diagnostic condition information 010 includes the first diagnostic initiation condition 011, the second diagnostic stabilization condition 022, and the third diagnostic completion condition 033.

[0051] Specifically, if the first diagnostic initiation condition 011 is met, the second delay filtering unit 720 is invoked or started; wherein, the second delay filtering unit 720 cyclically detects or scans the second diagnostic stabilization condition 022, and if the second stabilization condition 022 is met, the third comprehensive judgment unit 730 is invoked or started.

[0052] Furthermore, the third comprehensive judgment unit 730 cyclically detects or scans the third diagnostic completion condition 033. If the third diagnostic completion condition 033 is met, the relationship between the characteristic physical quantity 600 and / or the third preset statistical quantity 355 of the characteristic physical quantity 600 and the preset judgment criterion is compared to determine the third working state 345 of the thermostat. The third working state 345 includes the third fault state 399 and the third normal state 366.

[0053] Wherein: the first preprocessing unit 710 obtains the water temperature difference deltaT612 between the first engine main water temperature T1 and the second control zone water temperature T2; the second delayed filtration unit 720 detects engine operating condition information, including engine running duration, engine speed 666, engine speed fluctuation value and / or engine speed acceleration; the engine running duration is the length of time the engine has been running continuously since it started. Specifically, the third comprehensive judgment unit 730 can only be invoked or started when the engine running duration is greater than or equal to the delay time threshold t1 and the speed condition 220 is met at the same time; the speed condition 220 includes a first amplitude condition and / or a second fluctuation condition; the first amplitude condition is met when the engine speed 666 is greater than the preset speed threshold n; the second fluctuation condition is met when the engine acceleration is less than the preset acceleration threshold or the change in engine speed 666 within the preset time range is less than the fluctuation threshold X.

[0054] Furthermore, its third preset statistic 355 can be the temperature difference peak value deltaTmax699, which is the maximum value of the water temperature difference deltaT612 at different times; the first diagnostic initiation condition 011 includes the intake flow integral, and the second delay filter unit 720 and / or the third comprehensive judgment unit 730 can only be called or started when the intake flow integral is greater than or equal to the preset first flow integral threshold; its third diagnostic completion condition 033 includes at least one of the following conditions: the intake flow integral is greater than or equal to the third flow integral threshold, the first engine main water temperature T1 is greater than or equal to the first main temperature threshold, the first engine main water temperature T1 is greater than or equal to the second main temperature threshold and the water temperature difference deltaT612 is less than or equal to the third temperature difference threshold.

[0055] Wherein: the first diagnostic initiation condition 011 may also include an ambient temperature condition, which is satisfied only when the ambient temperature of the engine is greater than or equal to the first ambient temperature threshold; the first flow integral threshold is 100 grams, the first main temperature threshold is 76 degrees Celsius, the second main temperature threshold is 70 degrees Celsius, and the first ambient temperature threshold is -7 degrees Celsius.

[0056] Furthermore, such as Figure 1 , Figure 7 , Figure 8 , Figure 9 As shown, the engine main water temperature T1 can be collected from the engine coolant outlet pipe body 712, and the second control zone water temperature T2 can be collected from the radiator water tank outlet side water tank body 711; the engine is used in hybrid vehicles or vehicles with automatic start-stop control 900; the temperature difference peak value deltaTmax699 is refreshed or updated only when the second diagnostic stability enhancement condition 022 is met, otherwise the temperature difference peak value deltaTmax699 continues to use the value of the previous sampling time or the value obtained from the first sampling.

[0057] Wherein: If the third diagnostic completion condition 033 meets the preset requirements, then the third working state 345 is output; the third preset statistic 355 is the statistic of water temperature difference deltaT612 or the statistic constructed using the area method in thermostat diagnosis; if the peak temperature difference deltaTmax699 is greater than or equal to the fault threshold, then the third working state 345 is the third normal state 366, otherwise the third working state 345 is the third fault state 399; when constructing using the area method, within certain diagnostic condition constraints (similar to the temperature difference method), if the ratio of the integral of the temperature difference between the first and second channels to the integral of the temperature difference of the first channel, i.e., the "area ratio", is less than the threshold, then a fault is considered to exist; for example: main water temperature T1, second channel water temperature T2, the main water temperature at startup is T1_initial, The temperature difference between T1 and T2 is integrated to obtain S1, and the temperature difference between T1 and T1_initial is integrated to obtain S2. The area ratio is S = S1 / S2. If S < threshold, a fault is reported; if S >= threshold, there is no fault. When calculating the temperature difference area, similar schemes are used, such as removing areas with large speed fluctuations or adding a delay after repeated starts before calculation.

[0058] In addition, such as Figure 7 , Figure 8 , Figure 9 The computer storage medium 903 includes a storage medium body for storing a computer program; when executed by a microprocessor, the computer program can implement any of the thermostat diagnostic methods described above. Similarly, the controller 901 shown in the figure includes any of the diagnostic devices 700 described above; and / or any of the computer storage media 903.

[0059] In summary, by introducing a delayed filtering process, the embodiments of the present invention can avoid the influence of frequent start-stop conditions or speed fluctuation conditions on the temperature difference method in thermostat fault diagnosis, thereby improving the detection rate and reliability. By reasonably selecting parameters, data with large amplitude and fluctuation in characteristic physical quantity information can be removed, which is more conducive to the calibration of thermostat parameters. In addition, the method can effectively identify the engine's operating status and perform relevant diagnoses only in the stable operating range of speed, further improving the reliability of the diagnosis.

[0060] It should be noted that the above embodiments are only for more clearly illustrating the technical solution of the present invention. Those skilled in the art will understand that the implementation of the present invention is not limited to the above content. Any obvious changes, substitutions or replacements made based on the above content do not exceed the scope of the technical solution of the present invention. Other implementations will also fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A method for diagnosing thermostats, characterized in that, The system includes a first preprocessing step (100), a second delayed filtering step (200), and a third comprehensive judgment step (300). The first preprocessing step (100) acquires characteristic physical quantity information (600) and detects diagnostic condition information (010). The characteristic physical quantity information (600) includes a first engine main water temperature T1 (601) and a second control zone water temperature T2 (602). The diagnostic condition information (010) includes a first diagnostic initiation condition (011), a second diagnostic stabilization condition (022), and a third diagnostic completion condition (033). If the first diagnostic initiation condition (011) is met, the second delay filtering step (200) is entered; the second delay filtering step (200) repeatedly detects or scans the second diagnostic stabilization condition (022); if the second diagnostic stabilization condition (022) is met, the third comprehensive judgment step (300) is entered. The third comprehensive judgment step (300) cyclically detects or scans the third diagnostic completion condition (033). If the third diagnostic completion condition (033) is met, the third working state (345) of the thermostat is determined by comparing the relationship between the characteristic physical quantity (600) and / or the third preset statistical quantity (355) of the characteristic physical quantity (600) and the preset judgment criterion. The third working state (345) includes the third fault state (399) and the third normal state (366). The second delay filtering step (200) detects engine operating condition information, which includes engine running duration, engine speed (666), engine speed fluctuation value, and engine speed acceleration. The engine running duration is the length of time the engine has been running continuously since it was started. The third comprehensive determination step (300) can only be entered when the engine running duration is greater than or equal to the delay time threshold t1 (210) and the speed condition (220) is met at the same time; the speed condition (220) includes a first amplitude condition and a second fluctuation condition; the first amplitude condition is met when the engine speed (666) is greater than the preset speed threshold n; the second fluctuation condition is met when the engine acceleration is less than the preset acceleration threshold or the change in engine speed (666) within the preset time range is less than the fluctuation threshold X.

2. The thermostat diagnostic method as described in claim 1, wherein: The first preprocessing step (100) obtains the water temperature difference deltaT (612) between the first engine main water temperature T1 (601) and the second control area water temperature T2 (602).

3. The thermostat diagnostic method as described in claim 2, wherein: The third preset statistic (355) includes the temperature difference peak value deltaTmax (699), which is the maximum value of the water temperature difference deltaT (612) at different times; the first diagnostic initiation condition (011) includes the intake flow integral, and the second delay filtering step (200) and / or the third comprehensive judgment step (300) can only be entered when the intake flow integral is greater than or equal to the preset first flow integral threshold; the third diagnostic completion condition (033) includes at least one of the following conditions: the intake flow integral is greater than or equal to the third flow integral threshold, the first engine main water temperature T1 (601) is greater than or equal to the first main temperature threshold, the first engine main water temperature T1 (601) is greater than or equal to the second main temperature threshold and the water temperature difference deltaT (612) is less than or equal to the third temperature difference threshold.

4. The thermostat diagnostic method as described in claim 3, wherein: The first diagnostic initiation condition (011) also includes an ambient temperature condition, which is satisfied only when the ambient temperature of the engine is greater than or equal to a first ambient temperature threshold; the first flow integral threshold is 100 grams, the first main temperature threshold is 76 degrees Celsius, the second main temperature threshold is 70 degrees Celsius, and the first ambient temperature threshold is -7 degrees Celsius.

5. The thermostat diagnostic method as described in claim 3 or 4, wherein: The engine main water temperature T1 (601) is collected from the engine cooling water outlet pipe body (712), and the second control area water temperature T2 (602) is collected from the radiator water tank outlet side water tank body (711); the engine is used in a hybrid vehicle or a vehicle with automatic start-stop control (900); the temperature difference peak value deltaTmax (699) is refreshed or updated only when the second diagnostic stability enhancement condition (022) is met; otherwise, the temperature difference peak value deltaTmax (699) continues to use the value of the previous sampling time or the value obtained from the first sampling.

6. The thermostat diagnostic method as described in claim 3 or 4, wherein: If the third diagnostic completion condition (033) meets the preset requirements, the third working state (345) is output; the third preset statistic (355) is the statistic of the water temperature difference deltaT (612) or the statistic constructed by the area method in the thermostat diagnosis; if the temperature difference peak deltaTmax (699) is greater than or equal to the fault threshold, the third working state (345) is the third normal state (366), otherwise the third working state (345) is the third fault state (399).

7. A diagnostic device (700), comprising: The system comprises a first preprocessing unit (710), a second delay filtering unit (720), and a third comprehensive judgment unit (730); wherein the first preprocessing unit (710) acquires characteristic physical quantity information (600) and detects diagnostic condition information (010); the characteristic physical quantity information (600) includes a first engine main water temperature T1 (601) and a second control zone water temperature T2 (602), and the diagnostic condition information (010) includes a first diagnostic initiation condition (011), a second diagnostic stabilization condition (022), and a third diagnostic completion condition (033); If the first diagnostic initiation condition (011) is met, the second delay filtering unit (720) is invoked or started; the second delay filtering unit (720) continuously detects or scans the second diagnostic stabilization condition (022), and if the second diagnostic stabilization condition (022) is met, the third comprehensive judgment unit (730) is invoked or started. The third comprehensive judgment unit (730) cyclically detects or scans the third diagnostic completion condition (033). If the third diagnostic completion condition (033) is met, the third working state (345) of the thermostat is determined by comparing the relationship between the characteristic physical quantity (600) and / or the third preset statistical quantity (355) of the characteristic physical quantity (600) and the preset judgment criterion. The third working state (345) includes the third fault state (399) and the third normal state (366). The second delay filtering unit (720) detects engine operating condition information, which includes engine running duration, engine speed (666), engine speed fluctuation value, and engine speed acceleration. The engine running duration is the length of time the engine has been running continuously since it was started. The third comprehensive determination unit (730) may be invoked or started only when the engine running duration is greater than or equal to the delay time threshold t1 (210) and the speed condition (220) is met at the same time; the speed condition (220) includes a first amplitude condition and a second fluctuation condition; the first amplitude condition is met when the engine speed (666) is greater than the preset speed threshold n; the second fluctuation condition is met when the engine acceleration is less than the preset acceleration threshold or the change in engine speed (666) within the preset time range is less than the fluctuation threshold X.

8. The diagnostic device (700) as claimed in claim 7, wherein: The first preprocessing unit (710) obtains the water temperature difference deltaT (612) between the first engine main water temperature T1 (601) and the second control area water temperature T2 (602).

9. The diagnostic device (700) as claimed in claim 8, wherein: The third preset statistical quantity (355) includes the temperature difference peak value deltaTmax (699), which is the maximum value of the water temperature difference deltaT (612) at different times; the first diagnostic initiation condition (011) includes the intake flow integral, and the second delay filter unit (720) and / or the third comprehensive judgment unit (730) can only be called or started when the intake flow integral is greater than or equal to the preset first flow integral threshold; the third diagnostic completion condition (033) includes at least one of the following conditions: the intake flow integral is greater than or equal to the third flow integral threshold, the first engine main water temperature T1 (601) is greater than or equal to the first main temperature threshold, the first engine main water temperature T1 (601) is greater than or equal to the second main temperature threshold and the water temperature difference deltaT (612) is less than or equal to the third temperature difference threshold.

10. The diagnostic device (700) as claimed in claim 9, wherein: The first diagnostic initiation condition (011) also includes an ambient temperature condition, which is satisfied only when the ambient temperature of the engine is greater than or equal to a first ambient temperature threshold; the first flow integral threshold is 100 grams, the first main temperature threshold is 76 degrees Celsius, the second main temperature threshold is 70 degrees Celsius, and the first ambient temperature threshold is -7 degrees Celsius.

11. The diagnostic device (700) as claimed in claim 9 or 10, wherein: The engine main water temperature T1 (601) is collected from the engine cooling water outlet pipe body (712), and the second control area water temperature T2 (602) is collected from the radiator water tank outlet side water tank body (711); the engine is used in a hybrid vehicle or a vehicle with automatic start-stop control (900); the temperature difference peak value deltaTmax (699) is refreshed or updated only when the second diagnostic stability enhancement condition (022) is met; otherwise, the temperature difference peak value deltaTmax (699) continues to use the value of the previous sampling time or the value obtained from the first sampling.

12. The diagnostic device (700) as claimed in claim 9 or 10, wherein: If the third diagnostic completion condition (033) meets the preset requirements, the third working state (345) is output; the third preset statistic (355) is the statistic of the water temperature difference deltaT (612) or the statistic constructed by the area method in the thermostat diagnosis; if the temperature difference peak deltaTmax (699) is greater than or equal to the fault threshold, the third working state (345) is the third normal state (366), otherwise the third working state (345) is the third fault state (399).

13. A computer storage medium (903), comprising: A storage medium for storing a computer program; the computer program, when executed by a microprocessor, implements the thermostat diagnostic method as described in any one of claims 1 to 6.

14. A controller (901), comprising: The diagnostic device (700) as described in any one of claims 7 to 12; and / or the computer storage medium (903) as described in claim 13.

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