Expansion kettle detection method and system

Abstract

The invention relates to an expansion kettle detection method, which comprises the following steps: obtaining operation data of an expansion kettle, calculating state data of the expansion kettle based on the obtained operation data, the state data comprises cooling liquid average temperature data, liquid level change rate data, cooling liquid inlet and outlet temperature difference data and pressure change rate data; calculating pressure deviation data based on the acquired state data; and fault conditions are judged based on the obtained state data and pressure deviation data, wherein the fault conditions comprise serious leakage, slight leakage, sensor faults and gas mixing. According to the expansion kettle detection method and system, the leakage condition and category of the expansion kettle can be comprehensively and accurately judged, the limitation of single sensor detection is avoided, the conditions of false alarm and missing alarm are reduced through accurate fault judgment, and the overall operation stability of the system is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of automobile expansion water jug fault detection, and particularly relates to an expansion water jug detection method and system. BACKGROUND

[0002] With the continuous development of fuel cell technology, its application in the fields of automobiles, fixed power generation equipment, etc. is becoming increasingly widespread. As a kind of efficient and environmentally friendly energy conversion device, the cooling system of the fuel cell is crucial to ensuring its normal operation. The expansion water jug, as an important part of the fuel cell cooling system, is mainly used for storing coolant, buffering system pressure, preventing overheating or freezing, etc. However, in actual use, the expansion water jug may leak due to various reasons, resulting in the loss of coolant and affecting the normal operation of the fuel cell, and even possibly causing safety accidents. Therefore, timely and accurate detection of the leakage of the expansion water jug is of great significance to ensuring the safety and reliability of the fuel cell system.

[0003] In the prior art, the traditional expansion water jug leakage detection method mainly relies on a single sensor (such as a liquid level sensor or a pressure sensor), which is difficult to accurately distinguish different types of faults and degrees. Although some methods use multiple sensors, the data analysis and fault judgment are still not accurate enough, and the temperature, liquid level and pressure data cannot be effectively integrated for comprehensive analysis. Therefore, the present application proposes an expansion water jug detection method and system based on multi-sensor data, aiming to accurately detect the leakage and fault category of the expansion water jug, overcome the shortcomings of the prior art, and improve the safety and reliability of the fuel cell cooling system, as well as reduce maintenance costs. SUMMARY

[0004] The present application provides an expansion water jug detection method and system, which can accurately determine the leakage and category of the expansion water jug, avoid the limitations of single sensor detection, reduce false positives and false negatives through accurate fault judgment, and improve the overall operation stability of the system.

[0005] In a first aspect, the present application provides an expansion water jug detection method, comprising the following steps: Obtaining the running data of the expansion water jug, the running data including temperature data, liquid level data and pressure data, calculating the state data of the expansion water jug based on the obtained running data, the state data including average coolant temperature data, liquid level change rate data, coolant inlet and outlet temperature difference data and pressure change rate data; Calculating the pressure deviation data based on the obtained state data; Judging the fault condition based on the obtained state data and pressure deviation data, the fault condition including: severe leakage, slight leakage, sensor failure and gas mixing.

[0006] In combination with the first aspect, in an implementation, the pressure deviation data is calculated by the following formula: ; ; wherein, is a pressure value at a previous time point, is a current coolant average temperature, is a coolant average temperature at a previous time point, is an expected pressure value, is a current actually measured pressure value.

[0007] In combination with the first aspect, in an implementation, the judging of the fault condition based on the obtained state data and the pressure deviation data specifically comprises: if the liquid level change rate data is less than or equal to a set liquid level leakage threshold value, and the pressure change rate data is less than or equal to a set gas pressure leakage threshold value, then the fault condition is determined as a serious leakage; if the liquid level change rate data is greater than the set liquid level leakage threshold value but less than a negative value of a liquid level change rate threshold value, and the pressure change rate data is greater than the set gas pressure leakage threshold value but less than a pressure change rate threshold value, and a second derivative of the liquid level change rate data is less than 0, then the fault condition is determined as a slight leakage; if the liquid level change rate data is greater than or equal to the liquid level change rate threshold value, and the pressure change rate data is greater than an absolute value of the pressure change rate threshold value, and the coolant average temperature data is less than a set temperature threshold value, then the fault condition is determined as gas mixing; if the liquid level change rate data is less than the liquid level change rate threshold value, and the pressure change rate data is less than or equal to an absolute value of the pressure change rate threshold value, and the pressure deviation data is greater than a set first deviation threshold value, then the fault condition is determined as a sensor fault.

[0008] In combination with the first aspect, in an implementation, the liquid level change rate threshold value is obtained by the following formula: ; wherein, A is a basic liquid level value, is a temperature compensation coefficient, is a current coolant average temperature, is a temperature compensation starting value.

[0009] In combination with the first aspect, in an implementation, the pressure change rate threshold value is obtained by the following formula: ; wherein, is a basic pressure value, is an actual fan rotating speed, is a normalized coefficient of fan rotating speed.

[0010] In combination with the first aspect, in an implementation, the determining the fault condition based on the obtained state data and the pressure deviation data further comprises: performing a leakage warning based on the obtained pressure deviation data, the temperature difference data of the cooling liquid inlet and outlet, and the liquid level change rate data.

[0011] In combination with the first aspect, in an implementation, the performing the leakage warning based on the obtained pressure deviation data and the temperature difference data of the cooling liquid inlet and outlet specifically comprises: If the pressure deviation data is greater than a second deviation threshold, the temperature difference data of the cooling liquid inlet and outlet is greater than a set temperature difference threshold, and the third derivative of the liquid level change rate data is greater than a set derivative threshold, it is determined that there is a risk of leakage, and the leakage warning is performed.

[0012] In the second aspect, the embodiments of the present application provide an expansion kettle detection system, comprising: a data acquisition module configured to acquire running data of the expansion kettle; a data processing module configured to calculate state data and pressure deviation data of the expansion kettle based on the running data acquired by the data acquisition module; a data determining module configured to determine a fault condition based on the state data and the pressure deviation data calculated by the data processing module.

[0013] In combination with the second aspect, in an implementation, the system further comprises: a warning module configured to generate an early leakage warning signal based on the determination result of the data determining module.

[0014] In combination with the second aspect, in an implementation, the data acquisition module comprises: a temperature acquisition unit arranged at an outlet of cooling liquid of the expansion kettle; a pressure acquisition unit arranged in a gas cavity at a top of the expansion kettle; a liquid level acquisition unit arranged on an inner wall of the expansion kettle.

[0015] The technical scheme provided by the embodiments of the present application has the following beneficial effects: 1. The expansion kettle detection method and system can accurately distinguish different types of faults, such as severe leakage, slight leakage, sensor failure, and gas mixing, by comprehensively analyzing temperature data, liquid level data, and pressure data, thereby comprehensively and accurately determining the leakage condition and category of the expansion kettle, avoiding the limitations of single sensor detection, reducing false positives and false negatives through accurate fault determination, and improving the overall operation stability of the system.

[0016] 2、The expansion water bottle detection method and system introduces a temperature compensation mechanism to ensure the detection accuracy of liquid level changes under different temperature conditions, and introduces a heat dissipation working condition compensation mechanism to dynamically adjust the pressure threshold according to the fan speed, ensuring the detection accuracy of pressure changes under different heat dissipation conditions, thereby making the entire system more accurate under different conditions, further enhancing the safety and reliability of the system.

[0017] 3、The expansion water bottle detection method and system introduces an early leakage warning mechanism to issue an alarm in the early stage of leakage and remind maintenance personnel to take appropriate maintenance measures. Through accurate detection and timely handling of faults, the service life of the expansion water bottle and related components is greatly extended, reducing maintenance time and cost caused by fault downtime, further enhancing the safety and reliability of the system. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0019] Figure 1 The detection method of the present application is shown in the figure; Figure 2 The detection method of the present application is shown in the figure; Figure 3 The detection system of the present application is shown in the figure. DETAILED DESCRIPTION

[0020] In order to make those skilled in the art better understand the present application, the technical solutions in the embodiments of the present application will be described clearly and completely with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0021] Embodiment one: The first embodiment of the present application provides an expansion water bottle detection method, which can accurately judge the leakage condition and category of the expansion water bottle, avoid the limitation of single sensor detection, reduce false and missed reports through accurate fault judgment, and improve the overall operation stability of the system.

[0022] Specifically, please refer to Figure 1 and Figure 2 , comprising the following steps: S1, acquire running data of the expansion water kettle, the running data including temperature data, liquid level data and pressure data, calculate state data of the expansion water kettle based on the acquired running data, the state data including cooling liquid average temperature data, liquid level change rate data, cooling liquid inlet and outlet temperature difference data and pressure change rate data; The cooling liquid average temperature data is acquired by the following formula: ; The cooling liquid average temperature data is acquired by the following formula: The cooling liquid inlet temperature is T in. The cooling liquid outlet temperature is T out.

[0023] The liquid level change rate data is acquired by the following formula: ; The liquid level change rate data is acquired by the following formula: The current time cooling liquid liquid level value is H cur. The previous time cooling liquid liquid level value is H pre.

[0024] The cooling liquid inlet and outlet temperature difference data is acquired by the following formula: ; The cooling liquid inlet and outlet temperature difference data is acquired by the following formula: The cooling liquid inlet temperature is T in. The cooling liquid outlet temperature is T out.

[0025] The pressure change rate data is acquired by the following formula: ; The pressure change rate data is acquired by the following formula: The current actual measured pressure value is P cur. The previous time point pressure value is P pre.

[0026] S2, calculate pressure deviation data based on the acquired state data; The pressure deviation data is calculated by the following formula: ; ; The pressure deviation data is calculated by the following formula: The previous time point pressure value is P pre. The current cooling liquid average temperature is T cur. The previous time point cooling liquid average temperature is T pre. The expected pressure value is P exp. The current actual measured pressure value is P cur.

[0027] S3, judge fault conditions based on the acquired state data and pressure deviation data, the fault conditions including: serious leakage, slight leakage, sensor failure and gas mixing.

[0028] Specifically, A. If the liquid level change rate data is less than or equal to the set liquid level leakage threshold value, and the pressure change rate data is less than or equal to the set gas pressure leakage threshold value, then the fault condition is determined to be a serious leakage; The set liquid level leakage threshold value in this embodiment is preferably -0.15, and the set gas pressure leakage threshold value is preferably -0.1, that is: ≤-0.15 and ≤-0.1, it is determined to be a serious leakage.

[0029] B. If the liquid level change rate data is greater than the set liquid level leakage threshold value but less than the negative value of the liquid level change rate threshold value, and the pressure change rate data is greater than the set gas pressure leakage threshold value but less than the pressure change rate threshold value, and the second derivative of the liquid level change rate data is less than 0, then the fault condition is determined to be a slight leakage; The liquid level change rate threshold value in this embodiment is preferably 0.05, and the pressure change rate threshold value is preferably -0.03, that is: <-0.05 and -0.1 <-0.03 and The second derivative of the liquid level change rate data is less than 0, which is determined to be a slight leakage.

[0030] C. If the liquid level change rate data is greater than or equal to the liquid level change rate threshold value, and the pressure change rate data is greater than the absolute value of the pressure change rate threshold value, and the average temperature data of the cooling liquid is less than the set temperature threshold value, then the fault condition is determined to be gas mixing; The temperature threshold value in this embodiment is preferably 3℃, that is: 0.05≤ >0.03 and >3℃, it is determined to be gas mixing.

[0031] D. If the liquid level change rate data is less than the liquid level change rate threshold value, and the pressure change rate data is less than or equal to the absolute value of the pressure change rate threshold value, and the pressure deviation data is greater than the set first deviation threshold value, then the fault condition is determined to be a sensor failure; The first deviation threshold value in this embodiment is preferably 1, that is: <0.05 and ≤0.03 and >1, it is determined to be a sensor failure.

[0032] The set liquid level leakage threshold value is used to determine whether the liquid level drop rate of the cooling liquid is a serious leakage. If the liquid level change rate exceeds the liquid level leakage threshold value, it represents that the liquid level drops too fast, and a serious leakage occurs. This value is calibrated based on actual conditions or experiments, and is a fixed threshold value. The set air pressure leakage threshold is used to determine whether the air pressure drop rate is a serious leakage. If the air pressure change rate exceeds the air pressure leakage threshold, it represents that the air pressure drops too fast, and a serious leakage occurs. The value is calibrated based on actual conditions or experiments, and is a fixed threshold; The liquid level change rate threshold is used to determine whether the cooling liquid level drop rate is a slight leakage. It is dynamically set based on the average temperature of the cooling liquid, because the cooling liquid volume will expand with the temperature rise. In order to avoid the interference of expansion in leakage determination, the liquid level change rate threshold is dynamically set based on temperature compensation; The liquid level change rate threshold is obtained by the following formula: ; Wherein, A is the basic liquid level value, is the temperature compensation coefficient, is the current average temperature of the cooling liquid, is the temperature compensation starting value; In this embodiment, A is preferably 0.05mm, is preferably 0.002mm / s, is preferably 80℃, i.e.: ; The pressure change rate threshold is used to determine whether the air pressure drop rate is a slight leakage. It is dynamically set based on the speed of the cooling fan, because the speed of the cooling fan directly affects the cooling intensity, and in turn changes the system pressure. In order to avoid misjudgment of normal cooling pressure fluctuation as leakage, the pressure change rate threshold is dynamically set based on fan speed compensation; The pressure change rate threshold is obtained by the following formula: ; Wherein, is the basic pressure value, is the actual fan speed, is the fan speed normalization coefficient; In this embodiment, is preferably 0.03, is preferably 3000, i.e.: ; The temperature threshold is the critical value of the average temperature of the cooling liquid, which is the temperature threshold of gas mixing determination. It is consistent with the temperature compensation starting value of the liquid level change rate threshold, which ensures that only in low temperature environment, the abnormal rise of liquid level and pressure is attributed to gas mixing, and avoids the interference of high temperature expansion. Its setting needs to be combined with specific system parameters (such as cooling liquid type, working temperature range) and calibrated by experiments, and is a fixed threshold.

[0033] The first deviation threshold is the maximum allowed relative deviation between the actual pressure value and the expected pressure value calculated based on the ideal gas law. The first deviation threshold is a decisive condition for sensor fault determination. If the pressure deviation data is within the first deviation threshold, the sensor data is considered reliable, and the system continues to check other fault conditions. If the pressure deviation data is outside the first deviation threshold, the pressure sensor data is considered abnormal. Under normal operating conditions, the deviation of pressure and temperature should not exceed 100%, so the first deviation threshold is usually set to 1, but it can be adjusted according to specific requirements or system characteristics in actual engineering. It is a fixed threshold.

[0034] In addition, the method further comprises: S4, based on the obtained pressure deviation data, cooling liquid inlet and outlet temperature difference data, and liquid level change rate data, performing a leakage warning; Specifically: If the pressure deviation data is greater than the set second deviation threshold, and the cooling liquid inlet and outlet temperature difference data is greater than the set temperature difference threshold, and the third derivative of the liquid level change rate data is greater than the set derivative threshold, it is determined that there is a risk of leakage, and a leakage warning is performed.

[0035] The second deviation threshold is the relative deviation between the actual pressure value and the expected pressure value calculated based on the ideal gas law. It is used to determine whether there is a risk of leakage. If the pressure deviation data is greater than the set second deviation threshold, it indicates that there may be a risk of leakage. Leakage can cause abnormal pressure changes, resulting in an increase in the deviation between the actual pressure value and the expected pressure value. If the pressure deviation data exceeds the second deviation threshold but does not exceed the first deviation threshold, the system determines that there may be a risk of leakage. In this embodiment, the second deviation threshold is preferably 0.15. In addition, this value is calibrated based on actual conditions or experiments and is a fixed threshold. The temperature difference threshold is used to determine whether the cooling liquid inlet and outlet temperature difference is abnormal. When the cooling liquid inlet and outlet temperature difference data exceeds the temperature difference threshold, it indicates that the heat exchange efficiency of the cooling liquid may be affected, which may be caused by leakage. In this embodiment, the temperature difference threshold is preferably 10°C. The value is calibrated based on actual conditions or experiments and is a fixed threshold. The derivative threshold is used to determine whether the third derivative of the liquid level change rate data is abnormal. The third derivative of the liquid level change rate data reflects the trend of the liquid level change rate. When the third derivative of the liquid level change rate data is greater than the set derivative threshold, it indicates that the trend of the liquid level change rate is abnormal, which may be caused by leakage. In this embodiment, the inverse threshold is preferably 0.001. The value is calibrated based on actual conditions or experiments and is a fixed threshold. Specifically, when >0.15, and >10, and When the third derivative of the pressure is greater than 0.001, it is determined that there is a risk of leakage, and early leakage warning is performed.

[0036] Embodiment two: Based on the same technical concept as Embodiment one, Embodiment two of the present application also provides an expansion water jug detection system, as shown in the figure, comprising: Figure 3 A. A data acquisition module for acquiring operation data of the expansion water jug; The data acquisition module specifically comprises: A temperature acquisition unit arranged at the outlet of the expansion water jug cooling liquid, preferably a temperature sensor; A pressure acquisition unit arranged in the air cavity at the top of the expansion water jug, preferably a pressure sensor; A liquid level acquisition unit arranged on the inner wall of the expansion water jug, preferably a liquid level sensor.

[0037] B. A data processing module for calculating state data and pressure deviation data of the expansion water jug based on the operation data acquired by the data acquisition module, the specific calculation method being as shown in the manner disclosed in the S1 step and the S2 step of Embodiment one above; C. A data judgment module for determining the fault condition based on the state data and the pressure deviation data calculated by the data processing module, the judgment method being as shown in the S3 step disclosed in Embodiment one above.

[0038] D. An early warning module for generating an early leakage warning signal based on the judgment result of the data judgment module; It should be noted here that the early warning module is connected to the vehicle control system, and sends a signal to the vehicle control system based on the judgment result of the data judgment module, specifically: The early warning module transmits the early warning signal, the abnormal condition signal and the normal signal to the display screen of the vehicle control system to display specific fault information, including the words "leakage risk", "system normal" and "system failure", as well as related data.

[0039] By introducing the early leakage warning mechanism, an alarm can be sent in the early stage of leakage to remind maintenance personnel to take appropriate maintenance measures. Through accurate detection and timely handling of faults, the service life of the expansion water jug and related components is greatly prolonged, the maintenance time and cost caused by fault downtime are reduced, and the safety and reliability of the system are further enhanced.

[0040] ​In the description of the present application, it should be noted that the terms "upper", "lower", and the like are used for indicating the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as limiting the present application. Unless otherwise explicitly specified and limited, the terms "mounting", "connection", "connecting" should be interpreted broadly, for example, can be fixed connection, can also be detachable connection, or integrally connected; can be mechanical connection, can also be electrical connection; can be directly connected, can also be indirectly connected through an intermediate medium, can be the internal communication of two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0041] It should be noted that in the present application, relational terms such as "first" and "second", and the like are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variant thereof are intended to cover non-exclusive inclusion, so that a process, method, article or apparatus including a series of elements includes not only those elements, but also other elements not explicitly listed, or other elements inherent in such a process, method, article or apparatus. Without more limitations, the element defined by the statement "comprising a" does not exclude the presence of other identical elements in the process, method, article or apparatus including the element.

[0042] The above is only a specific embodiment of the present application, which enables those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied herein.

Claims

1. A method for testing an expansion kettle, characterized in that, Includes the following steps: The operating data of the expansion tank is acquired, including temperature data, liquid level data and pressure data. Based on the acquired operating data, the state data of the expansion tank is calculated, including average coolant temperature data, liquid level change rate data, coolant inlet and outlet temperature difference data and pressure change rate data. Pressure deviation data is calculated based on the acquired state data; The fault condition is determined based on the acquired status data and pressure deviation data. The fault conditions include: serious leakage, minor leakage, sensor failure, and gas mixing.

2. The method for detecting an expansion tank according to claim 1, characterized in that, The pressure deviation data is calculated using the following formula: ； ； in, The pressure value at the previous time point. This is the current average coolant temperature. The average coolant temperature at the previous time point. This is the expected pressure value. This represents the actual pressure value measured at the moment.

3. The method for detecting an expansion kettle according to claim 1, characterized in that, The method of determining the fault condition based on the acquired status data and pressure deviation data specifically includes: If the liquid level change rate data is less than or equal to the set liquid level leakage threshold, and the pressure change rate data is less than or equal to the set gas pressure leakage threshold, then the fault condition is determined to be a serious leak. If the liquid level change rate data is greater than the set liquid level leakage threshold but less than the negative value of the liquid level change rate threshold, and the pressure change rate data is greater than the set gas pressure leakage threshold but less than the pressure change rate threshold, and the second derivative of the liquid level change rate data is less than 0, then the fault condition is determined to be a minor leak. If the liquid level change rate data is greater than or equal to the liquid level change rate threshold, and the pressure change rate data is greater than the absolute value of the pressure change rate threshold, and the average coolant temperature data is less than the set temperature threshold, then the fault condition is determined to be gas mixing. If the liquid level change rate data is less than the liquid level change rate threshold, and the pressure change rate data is less than or equal to the absolute value of the pressure change rate threshold, and the pressure deviation data is greater than the set first deviation threshold, then the fault condition is determined to be a sensor fault.

4. The method for detecting an expansion kettle according to claim 3, characterized in that, The threshold for the rate of change of liquid level is obtained by the following formula: ； Where A is the base liquid level value. This is the temperature compensation coefficient. This is the current average coolant temperature. This is the starting value for temperature compensation.

5. The method for detecting an expansion kettle according to claim 3, characterized in that, The pressure change rate threshold is obtained using the following formula: ； in, Base pressure value, This refers to the actual fan speed. This is the normalization factor for the fan speed.

6. The method for detecting an expansion kettle according to claim 1, characterized in that, After determining the fault condition based on the acquired status data and pressure deviation data, the system also includes leak warning based on the acquired pressure deviation data, coolant inlet and outlet temperature difference data, and liquid level change rate data.

7. The method for detecting an expansion kettle according to claim 6, characterized in that, The leak warning based on the acquired pressure deviation data and coolant inlet / outlet temperature difference data specifically includes: If the pressure deviation data is greater than the set second deviation threshold, the coolant inlet and outlet temperature difference data is greater than the set temperature difference threshold, and the third derivative of the liquid level change rate data is greater than the set derivative threshold, then a leakage risk is determined, and a leakage warning is issued.

8. The expansion kettle detection system according to claim 1, characterized in that, include: The data acquisition module is used to acquire the operating data of the expansion kettle; The data processing module is used to calculate the status data and pressure deviation data of the expansion kettle based on the operating data obtained by the data acquisition module. The data judgment module is used to determine the fault condition based on the status data and pressure deviation data calculated by the data processing module.

9. The expansion kettle detection system according to claim 8, characterized in that, Also includes: The early warning module is used to generate early leakage warning signals based on the judgment results of the data judgment module.

10. The expansion kettle detection system according to claim 8, characterized in that, The data acquisition module includes: A temperature acquisition unit is located at the outlet of the coolant in the expansion tank; The pressure acquisition unit is located in the air chamber at the top of the expansion tank; The liquid level acquisition unit is located on the inner wall of the expansion tank.

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