Fault diagnosis method, thermostat diagnostic instrument, storage medium and controller

Abstract

The present invention belongs to the field of fault diagnosis technology, and in particular relates to a fault diagnosis method, a thermostat diagnostic instrument, a storage medium and a controller; the fault state is determined by detecting characteristic temperature information of two temperature sensors and comparing the numerical characteristics of the two temperatures under specific operating conditions; due to the introduction of the intervention process of the engine operating condition, the characteristic data is filtered out of accidental factors and interference data from the engine transition process during the comparison process, thereby improving the credibility of the diagnosis; the method and product of the present invention are particularly suitable for thermostat fault diagnosis in scenarios such as hybrid vehicles or frequent start-stop conditions and large fluctuations in engine speed, and are also applicable to related diagnostic processes of the sampling area method; in addition, when using the method and product of the present invention, the temperature difference between the two water lines of the thermostat cooling system in the fault state and the normal state is relatively large, and a lower threshold can be used, further improving the reliability of the diagnosis.

Description

Technical Field

[0001] The present invention belongs to the technical field of fault diagnosis, and in particular relates to a fault diagnosis method, a thermostat diagnostic instrument, a storage medium and a controller. Background Art

[0002] Fault diagnosis is a key component of intelligent control, playing a crucial role in improving system maintainability and, consequently, reliability. Technical standards, laws, and regulations are placing increasingly stringent demands on fault diagnosis in automated systems. In thermostat applications, the "temperature difference method" based on dual water temperature sensors is widely used for fault diagnosis. However, due to the wide variety of vehicle models, this method often suffers from a high false positive rate in some applications, impacting the proper functioning of related systems. This hinders both effective fault detection and stable equipment operation.

[0003] Among them, thermostat action / stuck failure is a common mechanical failure. Related technologies such as Figure 1 As shown in the left figure, when there is no fault, the thermostat can be closed normally, the cooling water temperature in the small loop increases, while the cooling water temperature in the large loop remains unchanged; when the water temperature in the small loop reaches the thermostat opening temperature, the thermostat opens, and the coolant in the large loop quickly heats up; before the thermostat opens, the coolant goes through the small loop, so the temperature difference between T1 and T2 is large. When the maximum temperature difference is greater than or equal to the threshold, it can be determined that there is no fault.

[0004] In addition, if Figure 1 As shown in the right figure, when there is a fault, the thermostat is stuck in the fully open position, closing the small circulation pipeline, and the coolant directly enters the large circulation system; at this time, the second water temperature sensor ECT2 measures the large circulation coolant temperature, that is, the water temperature T2 in the second control area. Since T2 rises very quickly, the temperatures of T1 and T2 are close, that is, the temperature difference is small, then it can be determined that the thermostat is stuck in the fully open position.

[0005] The above diagnostic method is the "temperature difference method"; however, for some vehicle models, especially hybrid vehicles, when the thermostat is stuck and normally open, the temperature difference method is difficult to effectively identify the related fault; in addition, if a higher fault threshold is set, the probability of false fault alarm will be higher. Summary of the Invention

[0006] An embodiment of the present invention discloses a fault diagnosis method, including a first preprocessing step, a second operating condition intervention step, and a third diagnostic output step; the first preprocessing step obtains characteristic physical quantity information for thermostat fault diagnosis and periodically or at a preset rhythm obtains trigger condition information; the characteristic physical quantity information includes a first engine main water temperature T1 and a second control area water temperature T2, and the trigger condition information includes a first trigger condition, a second trigger condition, and a third trigger condition; the trigger condition information includes thresholds of measurable physical quantities, which can be preset temperature parameters and / or flow parameters.

[0007] Specifically, if the second trigger condition is met, the second operating condition intervention step is entered; the second operating condition intervention step adjusts the engine to the preset first diagnostic operating condition and ensures that the duty cycle of the engine system water pump increases until the pump power or speed of the water pump is greater than the preset threshold.

[0008] Furthermore, if the third trigger condition is also met, the third diagnostic output step is entered; the fault state is determined by comparing the relationship between its characteristic physical quantity information and the preset first set of judgment thresholds or comparing the statistical amount of the characteristic physical quantity information with the preset second set of judgment thresholds.

[0009] Among them, if the first trigger condition is met, the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 is calculated and stored, and the first extreme value deltaMaxA of the first temperature difference deltaT at several sampling moments is obtained; if the second trigger condition is met and the first extreme value deltaMaxA is greater than or equal to the first temperature difference threshold TT1, the current diagnostic process is terminated and / or the thermostat normal flag is sent; if the second trigger condition is met and the first extreme value deltaMaxA is less than the first temperature difference threshold TT1, the first extreme value deltaMaxA is reset to zero and enter the next scanning or detection cycle.

[0010] Furthermore, its second operating condition intervention step can also obtain vehicle operating information to improve the diagnostic effect, and its operating information includes power and vehicle speed information; based on the operating information, the corresponding target speed and target torque are sent to the engine control unit; the engine control unit adjusts the engine to the second diagnostic operating condition according to the target speed and / or target torque.

[0011] The statistics of the characteristic physical quantity information may be statistics constructed using the area method in thermostat diagnosis, and it is necessary to ensure that the third trigger condition is achieved only after the second trigger condition is met.

[0012] The method of the present invention may also include a fourth review and debounce step; the fourth review and debounce step improves the detection data by delaying the first debounce time t: after the delay t, the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 is recalculated and stored and the second extreme value deltaMaxB of the first temperature difference deltaT at several sampling moments is obtained; wherein the statistics of the characteristic physical quantity information include the first extreme value deltaMaxA and / or the second extreme value deltaMaxB.

[0013] Specifically, if the first extreme value deltaMaxA or the second extreme value deltaMaxB is less than the second temperature difference threshold TT2, a thermostat fault message or a fault warning message is issued, and the intervention signal applied to the engine in the second operating condition intervention step is removed or the engine's operating condition is restored to the state before the second operating condition intervention step is executed.

[0014] Among them, the first trigger condition includes that the intake flow integral is greater than or equal to the first flow threshold FT1 and the first engine main water temperature T1 is less than the first starting temperature threshold TST1; the second trigger condition includes that the intake flow integral is greater than or equal to the second flow threshold FT2 and the first engine main water temperature T1 is greater than or equal to the second preheating temperature threshold TWT2; the third trigger condition includes that the intake flow integral is greater than or equal to the third flow threshold FT3 and the first engine main water temperature T1 is greater than or equal to the third preheating temperature threshold TWT3; in addition, the third trigger condition also includes that the first engine main water temperature T1 is greater than or equal to the fourth preheating temperature threshold TWT4 and the first temperature difference value deltaT is less than or equal to the fifth temperature difference threshold TT5.

[0015] Specifically, in the application scenario of the hybrid vehicle thermostat, the first flow threshold FT1 can be 100 grams, and the first starting temperature threshold TST1 can be 45 degrees Celsius; the second flow threshold FT2 can be 6 kilograms, and the second preheating temperature threshold TWT2 can be 65 degrees Celsius; the third flow threshold FT3 can be 10 kilograms, the third preheating temperature threshold TWT3 can be 76 degrees Celsius, the fourth preheating temperature threshold can be 70 degrees Celsius, and the fifth temperature difference threshold TT5 can be 5 degrees Celsius; the first temperature difference threshold TT1 can be 20 degrees Celsius, and the second temperature difference threshold TT2 can be 10 degrees Celsius.

[0016] Accordingly, in a thermostat diagnostic instrument disclosed in the present invention, a first preprocessing unit, a second working condition intervention unit, and a third diagnostic output unit may be provided; the first preprocessing unit obtains characteristic physical quantity information for thermostat fault diagnosis and periodically or at a preset rhythm obtains trigger condition information; the characteristic physical quantity information includes the first engine main water temperature T1 and the second control area water temperature T2, and the trigger condition information includes the first trigger condition, the second trigger condition, and the third trigger condition; the trigger condition information includes the threshold value of a measurable physical quantity, and the measurable physical quantity includes a preset temperature parameter and / or flow parameter.

[0017] Among them, if the second trigger condition is met, the second operating condition intervention unit is started to adjust the engine to the preset first diagnostic operating condition and ensure that the duty cycle of the engine system cooling water pump increases until the pump power or speed of the water pump is greater than the preset threshold; if the third trigger condition is further met, the third diagnostic output unit is started to compare the relationship between the characteristic physical quantity information and the preset first group of judgment thresholds or compare the relationship between the statistics of the characteristic physical quantity information and the preset second group of judgment thresholds to determine the fault state.

[0018] Specifically, if the first trigger condition is met, the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 is calculated and stored, and the first extreme value deltaMaxA of the first temperature difference deltaT at several sampling moments is obtained; if the second trigger condition is met and the first extreme value deltaMaxA is greater than or equal to the first temperature difference threshold TT1, the current diagnostic process is terminated and / or the thermostat normal flag is sent; if the second trigger condition is met and the first extreme value deltaMaxA is less than the first temperature difference threshold TT1, the first extreme value deltaMaxA is reset to zero and the next scanning or detection cycle is entered.

[0019] Among them, the second operating condition intervention unit can also obtain vehicle operating information, which includes power and vehicle speed information; based on the operating information, the corresponding target speed and target torque are sent to the engine control unit; the engine control unit adjusts the engine to the second diagnostic operating condition according to the target speed and / or target torque; at this time, the statistics of the characteristic physical quantity information can be a statistics constructed using the area method in thermostat diagnosis, and ensure that the third trigger condition can only be achieved after the second trigger condition is met.

[0020] Furthermore, the thermostat diagnostic instrument of the present invention may also include a fourth review and de-jitter unit; after the fourth review and de-jitter unit delays the first de-jitter time t, it re-calculates and stores the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 and obtains the second extreme value deltaMaxB of the first temperature difference deltaT at several sampling moments; wherein, the statistics of the characteristic physical quantity information include the first extreme value deltaMaxA and / or the second extreme value deltaMaxB.

[0021] Specifically, if the first extreme value deltaMaxA or the second extreme value deltaMaxB is less than the second temperature difference threshold TT2, a thermostat fault message or a fault warning message is issued, and the intervention signal applied to the engine by the second operating condition intervention unit is removed or the engine's operating condition is restored to the state before the second operating condition intervention unit is started.

[0022] Among them, the first trigger condition includes that the intake flow integral is greater than or equal to the first flow threshold FT1 and the first engine main water temperature T1 is less than the first starting temperature threshold TST1; the second trigger condition includes that the intake flow integral is greater than or equal to the second flow threshold FT2 and the first engine main water temperature T1 is greater than or equal to the second preheating temperature threshold TWT2; the third trigger condition includes that the intake flow integral is greater than or equal to the third flow threshold FT3 and the first engine main water temperature T1 is greater than or equal to the third preheating temperature threshold TWT3; the third trigger condition also includes that the first engine main water temperature T1 is greater than or equal to the fourth preheating temperature threshold TWT4 and the first temperature difference value deltaT is less than or equal to the fifth temperature difference threshold TT5.

[0023] Specifically, its first flow threshold FT1 can be 100 grams, and the first starting temperature threshold TST1 can be 45 degrees Celsius; the second flow threshold FT2 can be 6 kilograms, and the second preheating temperature threshold TWT2 can be 65 degrees Celsius; the third flow threshold FT3 can be 10 kilograms, the third preheating temperature threshold TWT3 can be 76 degrees Celsius, the fourth preheating temperature threshold can be 70 degrees Celsius, and the fifth temperature difference threshold TT5 can be 5 degrees Celsius; the first temperature difference threshold TT1 can be 20 degrees Celsius, and the second temperature difference threshold TT2 can be 10 degrees Celsius.

[0024] Correspondingly, the present invention also discloses a computer storage medium, including a storage medium body for storing a computer program; when the computer program is executed by a microprocessor, it can implement any of the above fault diagnosis methods; similarly, the controller disclosed therein can include any of the above thermostat diagnostic instruments and / or any computer storage medium, and similarly adopts the corresponding technical solutions, which will not be repeated here.

[0025] In summary, the fault status is determined by detecting the characteristic temperature information of two temperature sensors and comparing the numerical characteristics of the two temperatures under specific operating conditions; due to the introduction of the intervention process of the engine operating conditions, the characteristic data is filtered out during the comparison process. Accidental factors and interference data from the engine transition process are filtered out, thereby improving the credibility of the diagnosis.

[0026] The method and product of the present invention are particularly suitable for thermostat fault diagnosis in scenarios such as hybrid vehicles or those with frequent start-stop conditions and large fluctuations in engine speed. They are also applicable to the relevant diagnostic processes of the sampling area method. In addition, when using the method and product of the present invention, the temperature difference between the two water lines of the thermostat cooling system in the fault state and the normal state can be distinguished with a large degree, and a lower threshold can be used, further improving the reliability of the diagnosis.

[0027] It should be noted that the terms "first", "second" and similar terms used in this article are only for describing the various components of the technical solution, and do not constitute a limitation of the technical solution, nor can they be understood as an indication or suggestion of the importance of the corresponding elements; elements with terms such as "first", "second" and similar terms indicate that the corresponding technical solution contains at least one of the element. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] In order to more clearly illustrate the technical solution of the present invention and facilitate a further understanding of the technical effects, technical features and purposes of the present invention, the present invention is described in detail below in conjunction with the accompanying drawings. The accompanying drawings constitute an essential part of the specification and are used together with the embodiments of the present invention to illustrate the technical solution of the present invention, but do not constitute a limitation to the present invention.

[0029] The same reference numerals in the accompanying drawings represent the same components, specifically:

[0030] Figure 1 This is a schematic diagram of the thermostat diagnosis principle using the temperature difference method in related technology.

[0031] Figure 2 It is a schematic diagram of the thermostat diagnosis process using the temperature difference method in the related art.

[0032] Figure 3 This figure shows the influence of the water pump speed on the thermostat diagnosis in the embodiment of the present invention.

[0033] Figure 4 This is the effect of engine speed and load on thermostat diagnosis in an embodiment of the present invention.

[0034] Figure 5 Schematic diagram of the diagnostic process of an embodiment of the present invention.

[0035] Figure 6 Schematic diagram of the process of the present invention.

[0036] Figure 7 This is a schematic diagram of the structure of the thermostat diagnostic instrument of the present invention.

[0037] Figure 8 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 1 .

[0038] Figure 9 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 2 .

[0039] Figure 10 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 3 .

[0040] Figure 11 Schematic diagram of the layout structure of the product embodiment of the present invention Figure 4 .

[0041] in:

[0042] 010-diagnostic condition information;

[0043] 011-first trigger condition;

[0044] 022-Second trigger condition;

[0045] 033-The third trigger condition;

[0046] 100-first preprocessing step;

[0047] 111-temperature difference data acquisition step;

[0048] 200-second working condition intervention step;

[0049] 201-21st working condition intervention steps;

[0050] 202-22nd working condition intervention steps;

[0051] 222-Working condition intervention information;

[0052] 300-third diagnostic output step;

[0053] 345-third working state;

[0054] 366-third normal state;

[0055] 399-third fault state;

[0056] 400-Fourth review and debounce step;

[0057] 401-temperature difference peak value review step;

[0058] 511-first working stage;

[0059] 512-second working stage;

[0060] 521-third working condition stage;

[0061] 522-Fourth working condition stage;

[0062] 600-characteristic physical quantity information;

[0063] 601-first engine main water temperature T1;

[0064] 602-water temperature of the second control area T2;

[0065] 606-vehicle speed;

[0066] 612-water temperature difference deltaT;

[0067] 666-engine speed;

[0068] 678-water pump speed;

[0069] 699-peak temperature difference deltaTmax;

[0070] 700-Thermostat diagnostic instrument;

[0071] 710-first pre-processing unit;

[0072] 711- Radiator water tank outlet side water tank body;

[0073] 712-Engine cooling water outlet pipe body;

[0074] 720-second working condition intervention unit;

[0075] 730-third diagnostic output unit;

[0076] 740-fourth review and debounce unit;

[0077] 900-vehicles;

[0078] 901-controller;

[0079] 903-Computer storage media. DETAILED DESCRIPTION

[0080] The present invention will be further described in detail below with reference to the accompanying drawings and examples. Of course, the specific embodiments described below are only intended to explain the technical solutions of the present invention, rather than to limit the present invention. In addition, the parts described in the embodiments or drawings are merely illustrative of the relevant parts of the present invention, rather than the entire present invention.

[0081] like Figure 5 、 Figure 6The fault diagnosis method shown includes a first preprocessing step 100, a second working condition intervention step 200, and a third diagnosis output step 300; wherein, the first preprocessing step 100 obtains characteristic physical quantity information 600 for thermostat fault diagnosis and periodically or at a preset rhythm obtains trigger condition information 010.

[0082] Specifically, its characteristic physical quantity information 600 includes the first engine main water temperature T1 and the second control area water temperature T2, and its trigger condition information 010 includes the first trigger condition 011, the second trigger condition 022, and the third trigger condition 033; its trigger condition information 010 includes the threshold value of the measurable physical quantity, and the measurable physical quantity includes a preset temperature parameter and / or flow parameter.

[0083] Among them, if the second trigger condition 022 is met, the second operating condition intervention step 200 is entered; the second operating condition intervention step 200 adjusts the engine to the preset first diagnostic operating condition and ensures that the duty cycle of the engine cooling system water pump increases until the pump power or speed of the water pump is greater than the preset threshold.

[0084] In addition, if the third trigger condition 033 is further met, the third diagnostic output step 300 is entered to compare the relationship between the characteristic physical quantity information 600 and the preset first set of judgment thresholds or to compare the statistics of the characteristic physical quantity information 600 and the preset second set of judgment thresholds to determine the fault state.

[0085] Specifically, if the first trigger condition 011 is met, the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 is calculated and stored, and the first extreme value deltaMaxA of the first temperature difference deltaT at several sampling moments is obtained; if the second trigger condition 022 is met and the first extreme value deltaMaxA is greater than or equal to the first temperature difference threshold TT1, the current diagnostic process is terminated and / or the thermostat normal flag is sent; if the second trigger condition 022 is met and the first extreme value deltaMaxA is less than the first temperature difference threshold TT1, the first extreme value deltaMaxA is reset to zero and the next scanning or detection cycle is entered.

[0086] like Figure 5 、 Figure 6 and Figures 8 to 11 As shown, its second operating condition intervention step 200 obtains the operating information of the vehicle 900, which includes power and vehicle speed information; based on the operating information, the corresponding target speed and target torque are sent to the engine control unit; the engine control unit adjusts the engine to the second diagnostic operating condition according to the target speed and / or target torque; wherein, the statistics of the characteristic physical quantity information 600 can be constructed using the area method in thermostat diagnosis, and ensure that the third trigger condition 033 can be achieved only after the second trigger condition 022 is met.

[0087] Further, if Figure 6 As shown, this embodiment also includes a fourth review and de-bounce step 400; after the fourth review and de-bounce step 400 delays the first de-bounce time t, the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 is re-calculated and stored, and the second extreme value deltaMaxB of the first temperature difference deltaT at several sampling moments is obtained; wherein, the statistics of the characteristic physical quantity information 600 include the first extreme value deltaMaxA and / or the second extreme value deltaMaxB.

[0088] Among them, if the first extreme value deltaMaxA or the second extreme value deltaMaxB is less than the second temperature difference threshold TT2, a thermostat fault message or a fault warning message is issued, and the intervention signal applied to the engine by the second operating condition intervention step 200 is removed or the engine operating condition is restored to the state before the second operating condition intervention step 200 is executed.

[0089] Specifically, its first trigger condition 011 includes that the intake flow integral is greater than or equal to the first flow threshold FT1 and the first engine main water temperature T1 is less than the first starting temperature threshold TST1; its second trigger condition 022 includes that the intake flow integral is greater than or equal to the second flow threshold FT2 and the first engine main water temperature T1 is greater than or equal to the second preheating temperature threshold TWT2; its third trigger condition 033 includes that the intake flow integral is greater than or equal to the third flow threshold FT3 and the first engine main water temperature T1 is greater than or equal to the third preheating temperature threshold TWT3; its third trigger condition 033 also includes that the first engine main water temperature T1 is greater than or equal to the fourth preheating temperature threshold TWT4 and the first temperature difference value deltaT is less than or equal to the fifth temperature difference threshold TT5.

[0090] Among them, the first flow threshold FT1 can be 100 grams, and the first starting temperature threshold TST1 can be 45 degrees Celsius; the second flow threshold FT2 can be 6 kilograms, and the second preheating temperature threshold TWT2 can be 65 degrees Celsius; the third flow threshold FT3 can be 10 kilograms, the third preheating temperature threshold TWT3 can be 76 degrees Celsius, the fourth preheating temperature threshold can be 70 degrees Celsius, and the fifth temperature difference threshold TT5 can be 5 degrees Celsius; the first temperature difference threshold TT1 can be 20 degrees Celsius, and the second temperature difference threshold TT2 can be 10 degrees Celsius.

[0091] In such Figure 7 The thermostat diagnostic instrument 700 shown in FIG. 1 may include a first pre-processing unit 710, a second working condition intervention unit 720, and a third diagnostic output unit 730; the first pre-processing unit 710 obtains the following information: Figure 5The characteristic physical quantity information 600 for thermostat fault diagnosis is shown and trigger condition information 010 is obtained periodically or at a preset rhythm; its characteristic physical quantity information 600 includes a first engine main water temperature T1 and a second control area water temperature T2, and its trigger condition information 010 includes a first trigger condition 011, a second trigger condition 022, and a third trigger condition 033; its trigger condition information 010 includes a threshold value of a measurable physical quantity, and the measurable physical quantity includes a preset temperature parameter and / or a flow parameter; if the second trigger condition 022 is met, the second operating condition intervention unit 720 is started to adjust the engine to a preset first diagnostic operating condition and ensure that the duty cycle of the engine cooling system water pump increases until the pump power or speed of the water pump is greater than the preset threshold; if the third trigger condition 033 is further met, the third diagnostic output unit 730 is started to compare the characteristic physical quantity information 600 with the preset first set of judgment thresholds or compare the statistical quantity of the characteristic physical quantity information 600 with the preset second set of judgment thresholds to determine the fault state.

[0092] If the first trigger condition 011 is met, the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 is obtained and stored, and the first extreme value deltaMaxA of the first temperature difference deltaT at several sampling moments is obtained.

[0093] Specifically, if the second trigger condition 022 is met and the first extreme value deltaMaxA is greater than or equal to the first temperature difference threshold TT1, the current diagnostic process is terminated and / or the thermostat normal flag is sent; if the second trigger condition 022 is met and the first extreme value deltaMaxA is less than the first temperature difference threshold TT1, the first extreme value deltaMaxA is reset to zero and the next scanning / detection cycle is entered.

[0094] Furthermore, its second operating condition intervention unit 720 can also obtain operating information of the vehicle 900 to improve the diagnostic environment, and its operating information includes power and vehicle speed information; based on the operating information, the corresponding target speed and target torque are sent to the engine control unit; the engine control unit adjusts the engine to the second diagnostic operating condition according to the target speed and / or target torque; wherein, the statistics of the characteristic physical quantity information 600 include statistics constructed using the area method in thermostat diagnosis, and ensure that the third trigger condition 033 can only be achieved after its second trigger condition 022 is met.

[0095] Furthermore, this embodiment also includes the following Figure 7The fourth review and de-jitter unit 740 is shown; after the first de-jitter time t is delayed, the fourth review and de-jitter unit 740 re-calculates and stores the first temperature difference deltaT between the first engine main water temperature T1 and the second control area water temperature T2 and obtains the second extreme value deltaMaxB of the first temperature difference deltaT at several sampling moments; wherein, the statistics of the characteristic physical quantity information 600 include the first extreme value deltaMaxA and / or the second extreme value deltaMaxB.

[0096] Among them, if the first extreme value deltaMaxA or the second extreme value deltaMaxB is less than the second temperature difference threshold TT2, a thermostat fault message or a fault warning message is issued, and the intervention signal applied to the engine by the second operating condition intervention unit 720 is removed or the engine's operating condition is restored to the state before the second operating condition intervention unit 720 is started.

[0097] Specifically, its first trigger condition 011 includes that the intake flow integral is greater than or equal to the first flow threshold FT1 and the first engine main water temperature T1 is less than the first starting temperature threshold TST1; its second trigger condition 022 includes that the intake flow integral is greater than or equal to the second flow threshold FT2 and the first engine main water temperature T1 is greater than or equal to the second preheating temperature threshold TWT2; its third trigger condition 033 includes that the intake flow integral is greater than or equal to the third flow threshold FT3 and the first engine main water temperature T1 is greater than or equal to the third preheating temperature threshold TWT3; its third trigger condition 033 also includes that the first engine main water temperature T1 is greater than or equal to the fourth preheating temperature threshold TWT4 and the first temperature difference value deltaT is less than or equal to the fifth temperature difference threshold TT5.

[0098] Among them, the first flow threshold FT1 can be 100 grams, and the first starting temperature threshold TST1 can be 45 degrees Celsius; the second flow threshold FT2 can be 6 kilograms, and the second preheating temperature threshold TWT2 can be 65 degrees Celsius; the third flow threshold FT3 can be 10 kilograms, the third preheating temperature threshold TWT3 can be 76 degrees Celsius, the fourth preheating temperature threshold TWT4 can be 70 degrees Celsius, and the fifth temperature difference threshold TT5 can be 5 degrees Celsius; the first temperature difference threshold TT1 can be 20 degrees Celsius, and the second temperature difference threshold TT2 can be 10 degrees Celsius.

[0099] In such Figures 8 to 11 In the product line, its computer storage medium 903 includes a storage medium body for storing a computer program; when the computer program is executed by the microprocessor, it can be used to implement any of the above fault diagnosis methods; similarly, its controller 901 includes any of the above thermostat diagnostic instruments 700 and / or computer storage medium 903, and also implements the corresponding diagnostic process.

[0100] For hybrid vehicles, the process for actively diagnosing thermostat failures is as follows: After vehicle 900 is started, when the first trigger condition 011 is met, the temperature difference deltaT and the maximum temperature difference deltaTmaxA between the main water temperature and the secondary water temperature are calculated. When the second trigger condition 022 is met, deltaTmaxA is compared with the first temperature difference threshold TT1. When deltaTmaxA is less than the first temperature difference threshold TT1, it can be determined that the thermostat is suspected to be stuck and normally open, and deltaTmaxA will be restored to 0. The engine operating condition is then actively adjusted to a certain constant speed and load condition, and the corresponding engine water pump duty cycle or speed will also be increased to a larger value. The engine work generates heat to stabilize the engine water temperature within a certain range. When the thermostat is stuck and fully open, the water pump duty cycle is high, which can ensure that the secondary water temperature is close to the engine main water temperature. Thereafter, after the engine speed, load, and water pump speed are constant, a delay of time t is first made before restarting the calculation of deltaTmaxB.

[0101] Among them, when deltaTmaxB is greater than or equal to the first temperature difference threshold TT1, the engine operating condition is not actively adjusted, the rapid diagnosis is completed, and the diagnosis result shows that the thermostat is normal.

[0102] In addition, if the third trigger condition 033 is met, the fault is finally confirmed based on deltaTmaxB at this time: if deltaTmaxB is less than the second temperature difference threshold TT2, a thermostat stuck open fault is reported; otherwise, the thermostat fault diagnosis is completed and the system normal information is reported; if necessary, after the active diagnosis is completed, the diagnostic working condition can be exited to restore the engine and electronic water pump to normal operation.

[0103] Specifically, T1 is the engine main water temperature; T2 is the engine second-way water temperature; deltaT is the temperature difference between the first and second-way water temperatures; deltaTmaxA or deltaTmaxB is the maximum value of the temperature difference between the first and second-way water temperatures; its basic diagnostic conditions include the first trigger condition 011, the second trigger condition 022, and the third trigger condition 033.

[0104] The first trigger condition 011 includes:

[0105] 1) Intake flow integral >= first flow threshold FT1 (100g);

[0106] 2) The starting water temperature is less than the first starting temperature threshold TST1 (45 degrees Celsius).

[0107] The second trigger condition 022 includes:

[0108] 1) The intake flow integral is greater than or equal to the second flow threshold FT2 (6 kg);

[0109] 2) T1>= second preheating temperature threshold TWT2 (65 degrees Celsius).

[0110] The third trigger condition 033 includes:

[0111] 1) The intake flow integral is greater than or equal to the third flow threshold FT3 (10 kg);

[0112] 2) T1>= third preheating temperature threshold TWT3 (76 degrees Celsius);

[0113] 3) T1>=4th preheating temperature threshold TWT4 (70 degrees Celsius)

[0114] And deltaT<=the fifth temperature difference threshold TT5 (5 degrees Celsius).

[0115] Among them, the third trigger condition 033 is to detect that the deviation between the two water temperatures is small, so the fault can be diagnosed quickly; it should be noted that the third trigger condition 033 is more stringent than the second trigger condition 022; in addition, the first temperature difference threshold TT1 can be set to 20 degrees Celsius; the second temperature difference threshold TT2 can be set to 10 degrees Celsius; and ensure that the first temperature difference threshold TT1 is greater than the second temperature difference threshold TT2; specifically, it can be set according to the temperature difference performance of the two water temperatures where the faulty thermostat is installed.

[0116] In summary, by actively intervening in the engine operating conditions during the diagnostic process, the present invention improves the diagnostic effect of vehicle thermostat faults, especially for hybrid vehicles, and basically eliminates the occurrence of missed or false fault reports; among them, the temperature difference between the two water lines of the thermostat cooling system in the fault state and the normal state has a large degree of distinction, and a lower threshold can be used, thereby improving the reliability of the diagnosis; in addition, when the thermostat is stuck in the fully open position and there is a large temperature difference between the main water temperature and the second water temperature, the present invention can reduce the temperature difference by adjusting the operating conditions, set a reasonable threshold, and reliably report the fault.

[0117] It should be noted that the above embodiments are only for the purpose of more clearly illustrating the technical solutions of the present invention. Those skilled in the art will understand that the implementation methods of the present invention are not limited to the above contents, and obvious changes, replacements or substitutions based on the above contents do not exceed the scope covered by the technical solutions of the present invention; other implementation methods will also fall within the scope of the present invention without departing from the concept of the present invention.

Claims

1. A fault diagnosis method, characterized in that: The method comprises a first pre-processing step (100), a second working condition intervention step (200), and a third diagnosis output step (300); wherein the first pre-processing step (100) obtains characteristic physical quantity information (600) for thermostat fault diagnosis and obtains trigger condition information (010) at a preset rhythm; the characteristic physical quantity information (600) includes a first engine main water temperature T1 (601) and a second control area water temperature T2 (602); the trigger condition information (010) includes a first trigger condition (011), a second trigger condition (022), and a third trigger condition (033); the trigger condition information (010) includes a threshold value of a measurable physical quantity, and the measurable physical quantity includes The method further comprises the following steps: if the second trigger condition (022) is satisfied, the method enters the second working condition intervention step (200); the second working condition intervention step (200) adjusts the engine to the preset first diagnostic working condition and ensures that the duty cycle of the water pump of the engine increases until the pump power or speed of the water pump is greater than a preset threshold value; if the third trigger condition (033) is further satisfied, the method enters the third diagnostic output step (300), and compares the relationship between the characteristic physical quantity information (600) and the preset first group of judgment thresholds or compares the relationship between the statistics of the characteristic physical quantity information (600) and the preset second group of judgment thresholds to determine the fault state.

2. The fault diagnosis method according to claim 1, wherein: If the first trigger condition (011) is satisfied, a first temperature difference deltaT between the first engine main water temperature T1 (601) and the second control area water temperature T2 (602) is obtained and stored, and a first extreme value deltaMaxA of the first temperature difference deltaT at a plurality of sampling moments is obtained; If the second trigger condition (022) is satisfied and the first extreme value deltaMaxA is greater than or equal to the first temperature difference threshold TT1, then the current diagnostic process is terminated and / or a thermostat normal flag is sent; If the second trigger condition (022) is satisfied and the first extreme value deltaMaxA is less than the first temperature difference threshold TT1, the first extreme value deltaMaxA is reset to zero and the next scanning or detection cycle is entered.

3. The fault diagnosis method according to claim 2, wherein: The second working condition intervention step (200) acquires vehicle (900) operating information, wherein the operating information includes power level and vehicle speed information; Based on the operating information, sending corresponding target speed and target torque to the engine control unit; An engine control unit adjusts the engine to a second diagnostic operating condition according to the target speed and / or the target torque; The statistics of the characteristic physical quantity information (600) include statistics constructed using the area method in thermostat diagnosis, and ensure that the third trigger condition (033) is achieved only after the second trigger condition (022) is met.

4. The fault diagnosis method according to claim 3 further comprises a fourth review and debounce step (400); after the fourth review and debounce step (400) is delayed by the first debounce time t (401), the first temperature difference deltaT between the first engine main water temperature T1 (601) and the second control area water temperature T2 (602) is re-calculated and stored, and the second extreme value deltaMaxB of the first temperature difference deltaT at a plurality of sampling moments is obtained; wherein, The statistics of the characteristic physical quantity information (600) include the first extreme value deltaMaxA and / or the second extreme value deltaMaxB.

5. The fault diagnosis method according to claim 4, wherein: If the first extreme value deltaMaxA or the second extreme value deltaMaxB is less than the second temperature difference threshold value TT2, a thermostat fault message or a fault warning message is issued, and the intervention signal applied to the engine by the second working condition intervention step (200) is removed or the working condition of the engine is restored to the state before the second working condition intervention step (200) is executed; the first trigger condition (011) includes that the intake flow integral is greater than or equal to the first flow threshold value FT1 and the first engine main water temperature T1 (601) is less than the first starting temperature threshold value TST1; the second trigger condition (022) includes The intake flow integral is greater than or equal to the second flow threshold FT2, and the first engine main water temperature T1 (601) is greater than or equal to the second preheating temperature threshold TWT2; the third trigger condition (033) includes the intake flow integral being greater than or equal to the third flow threshold FT3, and the first engine main water temperature T1 (601) being greater than or equal to the third preheating temperature threshold TWT3; the third trigger condition (033) also includes the first engine main water temperature T1 (601) being greater than or equal to the fourth preheating temperature threshold TWT4 and the first temperature difference deltaT being less than or equal to the fifth temperature difference threshold TT5.

6. The fault diagnosis method according to claim 5, wherein: The first flow threshold FT1 is 100 grams, and the first starting temperature threshold TST1 is 45 degrees Celsius; the second flow threshold FT2 is 6 kilograms, and the second preheating temperature threshold TWT2 is 65 degrees Celsius; the third flow threshold FT3 is 10 kilograms, the third preheating temperature threshold TWT3 is 76 degrees Celsius, the fourth preheating temperature threshold is 70 degrees Celsius, and the fifth temperature difference threshold TT5 is 5 degrees Celsius; the first temperature difference threshold TT1 is 20 degrees Celsius, and the second temperature difference threshold TT2 is 10 degrees Celsius.

7. A thermostat diagnostic instrument (700), comprising a first pre-processing unit (710), a second working condition intervention unit (720), and a third diagnostic output unit (730); wherein: The first pre-processing unit (710) obtains characteristic physical quantity information (600) for thermostat fault diagnosis and obtains trigger condition information (010) periodically or at a preset rhythm; the characteristic physical quantity information (600) includes a first engine main water temperature T1 (601) and a second control area water temperature T2 (602); the trigger condition information (010) includes a first trigger condition (011), a second trigger condition (022), and a third trigger condition (033); the trigger condition information (010) includes a threshold value of a measurable physical quantity, and the measurable physical quantity includes a preset temperature parameter and / or flow rate. parameter; if the second trigger condition (022) is satisfied, the second operating condition intervention unit (720) is started to adjust the engine to a preset first diagnostic operating condition and ensure that the duty cycle of the water pump of the engine increases until the pump power or speed of the water pump is greater than a preset threshold value; if the third trigger condition (033) is further satisfied, the third diagnostic output unit (730) is started to compare the relationship between the characteristic physical quantity information (600) and the preset first group of judgment thresholds or to compare the relationship between the statistics of the characteristic physical quantity information (600) and the preset second group of judgment thresholds to determine the fault state.

8. The thermostat diagnostic instrument (700) according to claim 7, wherein: If the first trigger condition (011) is satisfied, a first temperature difference deltaT between the first engine main water temperature T1 (601) and the second control area water temperature T2 (602) is obtained and stored, and a first extreme value deltaMaxA of the first temperature difference deltaT at a plurality of sampling moments is obtained; If the second trigger condition (022) is satisfied and the first extreme value deltaMaxA is greater than or equal to the first temperature difference threshold TT1, then the current diagnostic process is terminated and / or a thermostat normal flag is sent; If the second trigger condition (022) is satisfied and the first extreme value deltaMaxA is less than the first temperature difference threshold TT1, the first extreme value deltaMaxA is reset to zero and the next scanning or detection cycle is entered.

9. The thermostat diagnostic instrument (700) according to claim 8, wherein: The second working condition intervention unit (720) obtains vehicle (900) operating information, the operating information including power level and vehicle speed information; Based on the operating information, sending corresponding target speed and target torque to the engine control unit; An engine control unit adjusts the engine to a second diagnostic operating condition according to the target speed and / or the target torque; The statistics of the characteristic physical quantity information (600) include statistics constructed using the area method in thermostat diagnosis, and ensure that the third trigger condition (033) is achieved only after the second trigger condition (022) is met.

10. The thermostat diagnostic instrument (700) as claimed in claim 9 further comprises a fourth review and de-jitter unit (740); after the fourth review and de-jitter unit (740) delays the first de-jitter time t (401), it re-calculates and stores the first temperature difference deltaT between the first engine main water temperature T1 (601) and the second control area water temperature T2 (602) and obtains the second extreme value deltaMaxB of the first temperature difference deltaT at a plurality of sampling moments; wherein, The statistics of the characteristic physical quantity information (600) include the first extreme value deltaMaxA and / or the second extreme value deltaMaxB.

11. The thermostat diagnostic instrument (700) according to claim 10, wherein: If the first extreme value deltaMaxA or the second extreme value deltaMaxB is less than the second temperature difference threshold value TT2, a thermostat fault message or a fault warning message is issued, and the intervention signal applied to the engine by the second working condition intervention unit (720) is removed or the working condition of the engine is restored to the state before the second working condition intervention unit (720) is started; the first trigger condition (011) includes that the intake flow integral is greater than or equal to the first flow threshold value FT1 and the first engine main water temperature T1 (601) is less than the first starting temperature threshold value TST1; the second trigger condition (022) includes The intake flow integral is greater than or equal to the second flow threshold FT2, and the first engine main water temperature T1 (601) is greater than or equal to the second preheating temperature threshold TWT2; the third trigger condition (033) includes the intake flow integral being greater than or equal to the third flow threshold FT3, and the first engine main water temperature T1 (601) being greater than or equal to the third preheating temperature threshold TWT3; the third trigger condition (033) also includes the first engine main water temperature T1 (601) being greater than or equal to the fourth preheating temperature threshold TWT4 and the first temperature difference deltaT being less than or equal to the fifth temperature difference threshold TT5.

12. The thermostat diagnostic instrument (700) according to claim 11, wherein: The first flow threshold FT1 is 100 grams, and the first starting temperature threshold TST1 is 45 degrees Celsius; the second flow threshold FT2 is 6 kilograms, and the second preheating temperature threshold TWT2 is 65 degrees Celsius; the third flow threshold FT3 is 10 kilograms, the third preheating temperature threshold TWT3 is 76 degrees Celsius, the fourth preheating temperature threshold is 70 degrees Celsius, and the fifth temperature difference threshold TT5 is 5 degrees Celsius; the first temperature difference threshold TT1 is 20 degrees Celsius, and the second temperature difference threshold TT2 is 10 degrees Celsius.

13. A computer storage medium (903), comprising a storage medium body for storing a computer program; when the computer program is executed by a microprocessor, the fault diagnosis method according to any one of claims 1 to 6 is implemented.

14. A controller (901), comprising the thermostat diagnostic instrument (700) according to any one of claims 7 to 12 and / or the computer storage medium (903) according to claim 13.

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