Calibration method and system for water outlet temperature sensor of water heating electric heater and new energy automobile

Abstract

The invention provides a verification method and system for a water outlet temperature sensor of a water heating electric heater and a new energy automobile. The method comprises the steps that the water outlet temperature T1 of the water heating electric heater is estimated based on the current water inlet temperature, the environment temperature, the heating power degree and the cooling liquid flow; and the water outlet temperature T2 detected by a temperature sensor at the water outlet of the water heating electric heater is read, the difference value T between the water outlet temperature T1 and the water outlet temperature T2 is calculated, and if the absolute value of the deviation corresponding to the difference value T is larger than a set deviation threshold value, it is determined that temperature sensing at the water outlet is invalid. A temperature sensor does not need to be additionally arranged at a water outlet of the water heating electric heater for effective detection of the outlet water temperature, and the outlet water temperature is predicted by means of the environment temperature, the cooling liquid flow, the inlet water temperature and the heating power of the heater. Effective detection is carried out on the outlet water temperature detected by the temperature sensor at the outlet based on the predicted outlet water temperature, the detection method is simple and easy to operate, and the production cost is reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of outlet temperature detection, and provides a method and system for calibrating an outlet temperature sensor of a water-heating electric heater and a new energy vehicle. Background Art

[0002] For the functional safety level requirement of ASIL B, it is necessary to calibrate the accuracy and effectiveness of the outlet temperature sensor and the inlet temperature sensor of the water-heating electric heating monomer component of the battery thermal management system.

[0003] The inlet temperature sensor is arranged at the inlet of the heater, and the outlet temperature sensor is arranged at the outlet of the heater. Water flows into the heater from the inlet, and the heater heats the flowing water. After heating, the water flows out from the outlet. The water temperature of the water flowing through the inlet temperature sensor is usually low, so the probability of failure of the inlet temperature sensor is relatively low. While the water temperature of the water flowing through the outlet temperature sensor is high, and the environment where the outlet temperature sensor is located is harsher than that of the inlet temperature sensor. Therefore, the outlet temperature sensor is more likely to fail.

[0004] In order to ensure the acquisition of an effective and relatively accurate outlet temperature, the current common method is to set two outlet temperature sensors at the outlet. The installation positions of the two outlet temperature sensors are close to each other, and the water temperatures detected by the two outlet temperature sensors are mutually calibrated to ensure the accuracy of the outlet temperature. However, setting two outlet temperature sensors at the outlet has the problem of high cost. Summary of the Invention

[0005] In view of this, the present application provides a method for calibrating an outlet temperature sensor of a water-heating electric heater, aiming to improve the above problems.

[0006] Specifically, it includes the following technical solutions:

[0007] On the one hand, an embodiment of the present application provides a method for calibrating an outlet temperature sensor of a water-heating electric heater, and the method is as follows:

[0008] (1) Estimate the outlet water temperature T1 of the water-heating electric heater based on the current inlet water temperature, ambient temperature, heating power and coolant flow rate;

[0009] (2) Read the outlet water temperature T2 detected by the temperature sensor at the outlet of the water-heating electric heater, calculate the difference △T between the outlet water temperature T1 and the outlet water temperature T2. If the absolute value of the deviation corresponding to the difference △T is greater than the set deviation threshold, it is determined that the temperature sensor at the outlet is invalid.

[0010] In some embodiments of the present invention, when the temperature sensing at the water outlet is effective, the temperature value detected by the temperature sensing at the water outlet is used as the outlet water temperature.

[0011] In some embodiments of the present invention, the outlet water temperature T1 includes a first outlet water temperature T1 and a second outlet water temperature T1. When the difference between the first outlet water temperature T1 and the second outlet water temperature T1 is within the allowable difference range, the average value of the first outlet water temperature T1 and the second outlet water temperature T1 is used as the outlet water temperature T1.

[0012] In some embodiments of the present invention, when the difference between the first outlet water temperature T1 and the second outlet water temperature T1 exceeds the allowable difference range, the first outlet water temperature T1 and the second outlet water temperature T1 are used as the outlet water temperature T1, and at the same time, the confidence level of the effective detection result of the temperature sensing at the water outlet is reduced.

[0013] In some embodiments of the present invention, the calculation method of the first outlet water temperature T1 is specifically as follows:

[0014] Construct a heating efficiency mapping table of the heater under different ambient temperatures and coolant flow rates, and find the heating efficiency corresponding to the current ambient temperature and the current coolant flow rate in the heating efficiency mapping table;

[0015] Determine the heating efficiency of the heater under the current ambient temperature and the current coolant flow rate λ , and then calculate the current inlet water temperature T0 and the heating power P corresponding to the first outlet water temperature T1.

[0016] In some embodiments of the present invention, the current inlet water temperature T0 , the heating power of the heater P and the heating efficiency are input into the outlet water temperature calculation model to calculate the first outlet water temperature T1. Among them, the outlet water temperature calculation model is specifically as follows:

[0017]

[0018] Among them, t is the residence time of water in the heater, m is the mass of water passing through the heater within the time t and c is the specific heat capacity of water.

[0019] In some embodiments of the present invention, the method for determining the second outlet water temperature T1 is as follows:

[0020] Construct an outlet water temperature mapping table under different ambient temperatures, heating powers, inlet water temperatures and coolant flow rates, and find the outlet water temperature corresponding to the current inlet water temperature, the current ambient temperature, the current heating power and the current coolant flow rate in the outlet water temperature mapping table, and use the found outlet water temperature as the second outlet water temperature T1.

[0021] On the other hand, an embodiment of the present application provides a verification system for the outlet temperature sensor of a water heating electric heater, and the system includes:

[0022] A first temperature sensor disposed at the water inlet of the water heating electric heater, a second temperature sensor disposed at the water outlet of the water heating electric heater, and a processor communicatively connected to the first temperature sensor and the second temperature sensor;

[0023] The first temperature sensor is used to monitor the inlet water temperature at the water inlet of the water heating electric heater and send it to the processor, and the second temperature sensor is used to monitor the outlet water temperature at the water outlet of the water heating electric heater and send it to the processor. The processor verifies whether the second temperature sensor is invalid based on the above method for verifying the outlet temperature sensor of the water heating electric heater.

[0024] In some embodiments of the present invention, the system further includes:

[0025] A prompt unit communicatively connected to the processor;

[0026] When it is detected that the second temperature sensor fails, a reminder of the failure of the second temperature sensor is sent through the prompt unit.

[0027] On the other hand, an embodiment of the present application provides a new energy vehicle, and the above verification system for the outlet temperature sensor of the water heating electric heater is integrated on the new energy vehicle.

[0028] There is no need to add a temperature sensor at the water outlet of the water heating electric heater to detect the effectiveness of the outlet water temperature. Instead, the outlet water temperature is predicted by means of the ambient temperature, the coolant flow rate, the inlet water temperature, and the heating power of the heater. The effectiveness of the outlet water temperature detected by the temperature sensor at the outlet is detected based on the predicted outlet water temperature. The detection method is simple and easy to operate, and the production cost is reduced. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0030] Figure 1 It is a schematic structural diagram of the verification system for the outlet temperature sensor of the water heating electric heater provided by the embodiment of the present invention;

[0031] Figure 2 It is a flowchart of the method for verifying the outlet temperature sensor of the water heating electric heater provided by the embodiment of the present invention;

[0032] Through the above-mentioned drawings, specific embodiments of the present application have been shown, and more detailed descriptions will be provided hereinafter. These drawings and textual descriptions are not intended to limit the scope of the concept of the present application in any way, but to illustrate the concept of the present application to those skilled in the art by referring to specific embodiments. Detailed implementation manners

[0033] The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part rather than all of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without creative efforts shall fall within the protection scope of the present application.

[0034] Unless otherwise defined, all technical terms used in the embodiments of the present application have the same meaning as commonly understood by those of ordinary skill in the art.

[0035] Figure 1 The following is a schematic structural diagram of the outlet water temperature sensor calibration system for the water-heating electric heater provided in the embodiments of the present invention. For the sake of convenience of description, only the parts related to the embodiments of the present invention are shown. The system includes:

[0036] A first temperature sensor is arranged at the water inlet of the water-heating electric heater, a second temperature sensor is arranged at the water outlet of the water-heating electric heater, a processor communicatively connected to the first temperature sensor and the second temperature sensor, and a prompting unit communicatively connected to the processor. The first temperature sensor is used to monitor the inlet water temperature at the water inlet of the water-heating electric heater and send it to the processor. The second temperature sensor is used to monitor the outlet water temperature at the water outlet of the water-heating electric heater and send it to the processor. The processor calibrates whether the second temperature sensor is invalid based on the following method for calibrating the outlet water temperature sensor of the water-heating electric heater. When it is detected that the second temperature sensor is effective, the temperature value detected by the second temperature sensor is the outlet water temperature of the water-heating electric heater at the water outlet. When it is detected that the second temperature sensor fails, a reminder of the failure of the second temperature sensor is sent through the prompting unit, facilitating the user to repair it in time.

[0037] Figure 2 The following is a flowchart of the method for calibrating the outlet water temperature sensor of the water-heating electric heater provided in the embodiments of the present invention. The method is specifically as follows:

[0038] (1) Estimate the outlet water temperature T1 of the water-heating electric heater based on the current inlet water temperature, ambient temperature, heating power, and coolant flow rate;

[0039] In an embodiment of the present invention, the inlet water temperature is detected by a first temperature sensor, and the ambient temperature can be directly read from the vehicle. For example, data is obtained through a weather station in vehicle networking technology, or it can be detected by an external temperature sensor configured in the vehicle and uploaded to the vehicle. The heating power is read from the heater in the water-cooled electric heater, and the coolant flow rate is obtained from the cooling system configured in the vehicle.

[0040] (2) Read the outlet water temperature T2 detected by the second temperature sensor at the outlet, calculate the difference ΔT between the outlet water temperature T1 and the outlet water temperature T2. If the absolute value of the deviation corresponding to the difference ΔT is greater than the set deviation threshold, it is determined that the second temperature sensor is invalid.

[0041] If the absolute value of the deviation corresponding to the difference is less than or equal to the set deviation threshold, it is determined that the second temperature sensor is effective. At this time, since the outlet water temperature T2 detected by the second temperature sensor is more accurate than the estimated outlet water temperature T1, the outlet water temperature T2 detected by the second temperature sensor is used as the final outlet water temperature at this time. Of course, in the case where the second temperature sensor is invalid, after issuing a relevant invalid prompt, in order to ensure the normal operation of the water-cooled electric heater, the estimated outlet water temperature T1 is used as the final outlet water temperature at this time.

[0042] In an embodiment of the present invention, calculate the ratio of the difference ΔT to the estimated outlet water temperature T1. When |ΔT / T1| ≤ 0.5%, the deviation corresponding to the difference ΔT is less than or equal to the set deviation threshold at this time, and it is determined that the second temperature sensor is effective; when |ΔT / T1| > 0.5%, the deviation corresponding to the difference ΔT is greater than the set deviation threshold at this time, and it is determined that the second temperature sensor is invalid.

[0043] In an embodiment of the present invention, the method for estimating the outlet water temperature T1 is specifically as follows:

[0044] Determine the heating efficiency of the heater at the current ambient temperature and the current coolant flow rate λ , and then calculate the current inlet water temperature T0 and the heating power P corresponding to the outlet water temperature T1.

[0045] Since the ambient temperature and the coolant flow rate have a relatively large impact on the heating efficiency of the heater, therefore, it is necessary to first construct a heating efficiency mapping table of the heater under different ambient temperatures and coolant flow rates, find the heating efficiency corresponding to the current ambient temperature and the current coolant flow rate in the heating efficiency mapping table, and input the current inlet water temperature T0 , the heating power of the heater P and the heating efficiency into the outlet water temperature calculation model to obtain the outlet water temperature T1. Among them, the outlet water temperature calculation model is specifically as follows:

[0046]

[0047] wherein, t is the residence time of water in the heater, and m is the time t the mass of water passing through the heater within, parameter t and parameter m is a fixed value, and c is the specific heat capacity of water.

[0048] Since the heating efficiency cannot be directly detected by a sensor, therefore, the outlet water temperature of the heater under different ambient temperatures and coolant flow rates is calibrated. The inlet water temperature and the heating power value are fixed, the rated heating power is adopted for the heating power, the ambient temperature and the coolant flow rate are changed, and when the temperature sensor at the outlet is normal, the outlet water temperature is read, and the heating efficiency of the heater under the current ambient temperature and coolant flow rate is calculated through the above outlet water temperature calculation model.

[0049] In another embodiment of the present invention, the outlet water temperature T1 is determined by looking up a table. Since the outlet water temperature is greatly affected by the ambient temperature, the coolant flow rate, the inlet water temperature T0 and the heating power of the heater P a mapping table of the outlet water temperature under different ambient temperatures, heating powers, inlet water temperatures, and coolant flow rates is constructed, and the outlet water temperature corresponding to the current inlet water temperature, the current ambient temperature, the current heating power, and the current coolant flow rate is found in the mapping table of the outlet water temperature, and this outlet water temperature is used as the outlet water temperature T1.

[0050] In the embodiment of the present invention, the construction method of the mapping table of the outlet water temperature is specifically as follows:

[0051] (11) Determine the ambient temperature and the heating power, and calibrate the outlet water temperature under different inlet water temperatures and coolant flow rates;

[0052] (12) Change the ambient temperature within the set ambient temperature range, and execute step (11);

[0053] (13) Change the heating power within the set heating power range, and execute step (11);

[0054] Based on steps (11)-(13), the outlet water temperatures under different ambient temperatures, heating powers, inlet water temperatures, and coolant flow rates can be obtained, and the calibration of the water temperature mapping table is completed.

[0055] The range of the inlet water temperature is -40 to 60 degrees, the range of the coolant flow rate is 0 to 14 L / min; the range of the ambient temperature is 0 - 40 degrees, the range of the heating power is 200 - 8000 w, the inlet water temperature increases in increments of 10 degrees, the coolant flow rate increases in increments of 2 L / min, and the ambient temperature increases in increments of 5 degrees.

[0056] If the outlet water temperature T1 is determined by looking up a table, a large amount of calibration is required in the early stage, and a large amount of calibrated data needs to be stored in the later stage, but the computational workload is small. When the calibration and calculation are combined to determine the outlet water temperature T1, only the calibration of the heater heating efficiency mapping table needs to be completed in the early stage, which greatly reduces the calibration workload, and the amount of calibration data to be stored later is small, but it requires a certain amount of resources for calculation. The above two methods for determining the outlet water temperature T1 can be selected according to the actual situation of the vehicle.

[0057] In the embodiment of the present invention, since the outlet water temperature T1 is used as the reference outlet water temperature for detecting whether the second temperature sensor fails, therefore, ensuring the accuracy of the outlet water temperature T1 can greatly improve the failure detection ability of the second temperature sensor. It is also possible to consider using the above two methods for determining the outlet water temperature at the same time, and the two outlet water temperatures are mutually verified. The outlet water temperature T1 determined by the above two methods is respectively called the first outlet water temperature T1 and the second outlet water temperature T1. When the deviation between the first outlet water temperature T1 and the second outlet water temperature T1 is small, the average value of the first outlet water temperature T1 and the second outlet water temperature T1 is used as the outlet water temperature T1 for the failure detection of the second temperature sensor. However, when the deviation between the first outlet water temperature T1 and the second outlet water temperature T1 is large, it is impossible to determine whether there is a deviation in the estimation of the first outlet water temperature T1 or the second outlet water temperature T1 at this time. Therefore, at this time, the first outlet water temperature T1 or the second outlet water temperature T1 can be selected as the outlet water temperature T1 according to the accuracy for the failure detection of the second temperature sensor, and the confidence level of the detection result of the failure detection is reduced. Of course, it can also be considered that there is no credible outlet water temperature T1 at this time, and the failure detection of the second temperature sensor is not performed.

[0058] The present invention does not need to add a temperature sensor at the outlet of the water heating electric heater to detect the effectiveness of the outlet water temperature, but predicts the outlet water temperature by means of the ambient temperature, the coolant flow rate, the inlet water temperature and the heating power of the heater, and detects the effectiveness of the outlet water temperature detected by the temperature sensor at the outlet based on the predicted outlet water temperature. The detection method is simple and easy to operate, and the production cost is reduced.

[0059] In another embodiment of the present invention, a new energy vehicle is also provided. The outlet temperature sensor calibration system of the above water heating electric heater is integrated on the new energy vehicle. Only one temperature sensor needs to be equipped at the outlet of the water heating electric heater. The outlet water temperature is predicted by means of the ambient temperature, the coolant flow rate, the inlet water temperature and the heating power of the heater, and the effectiveness of the outlet water temperature detected by the temperature sensor at the outlet is detected based on the predicted outlet water temperature. The detection method is simple and easy to operate, and the production cost is reduced.

[0060] Other embodiments of the present application will be readily contemplated by those skilled in the art upon consideration of the specification and practice of the present application disclosed herein. The present application is intended to cover any variations, uses, or adaptations of the present application, which follow the general principles of the present application and include known common knowledge or conventional technical means in the technical field not disclosed in the present application. The specification and examples are only regarded as exemplary.

[0061] It should be understood that the present application is not limited to the exact structures described above and shown in the drawings, and various modifications and changes can be made without departing from its scope. The scope of the present application is only limited by the appended claims.

Claims

1. A method for calibrating the outlet temperature sensor of a water heating and electric heater, characterized in that, The method is specifically as follows: (1) Estimate the outlet water temperature T1 of the water-heating electric heater based on the current inlet water temperature, ambient temperature, heating power, and coolant flow rate; (2) Read the outlet water temperature T2 detected by the temperature sensor at the outlet of the water-heating electric heater, calculate the difference ΔT between the outlet water temperature T1 and the outlet water temperature T2. If the absolute value of the deviation corresponding to the difference ΔT is greater than the set deviation threshold, it is determined that the temperature sensor at the outlet is invalid.

2. The method for calibrating the outlet water temperature sensor of the water heating and electric heater according to claim 1, wherein, When the temperature sensor at the outlet is valid, the temperature value detected by the temperature sensor at the outlet is used as the outlet water temperature.

3. The method for calibrating the outlet water temperature sensor of the water heating and electric heater according to claim 1, characterized in that, The outlet water temperature T1 includes a first outlet water temperature T1 and a second outlet water temperature T1. When the difference between the first outlet water temperature T1 and the second outlet water temperature T1 is within the allowable difference range, the average value of the first outlet water temperature T1 and the second outlet water temperature T1 is used as the outlet water temperature T1.

4. The method for calibrating the outlet water temperature sensor of the water heating and electric heater according to claim 1, characterized in that, When the difference between the first outlet water temperature T1 and the second outlet water temperature T1 exceeds the allowable difference range, the first outlet water temperature T1 and the second outlet water temperature T1 are used as the outlet water temperature T1, and at the same time, the confidence level of the effective detection result of the temperature sensor at the outlet is reduced.

5. The method for calibrating the outlet temperature sensor of the water-heating electric heater according to claim 3, wherein the calculation method of the first outlet water temperature T1 is specifically as follows: Construct a heating efficiency mapping table of the heater under different ambient temperatures and coolant flow rates, and find the heating efficiency corresponding to the current ambient temperature and the current coolant flow rate in the heating efficiency mapping table; Determine the heating efficiency of the heater at the current ambient temperature and the current coolant flow rate λ , and then calculate the current inlet water temperature T0 and the heating power P corresponding to the first outlet water temperature T1.

6. The method for calibrating the outlet water temperature sensor of the water heating and electric heater according to claim 5, characterized in that, The current inlet water temperature T0 , the heating power of the heater P and the heating efficiency are input into the outlet water temperature calculation model to calculate the first outlet water temperature T1. The specific outlet water temperature calculation model is as follows: Among them, t is the residence time of water in the heater, m is the mass of water passing through the heater within time t , and c is the specific heat capacity of water.

7. The method for calibrating the outlet water temperature sensor of the water heating and electric heater according to claim 3, characterized in that, The determination method of the second outlet water temperature T1 is as follows: Construct an outlet water temperature mapping table under different ambient temperatures, heating powers, inlet water temperatures, and coolant flow rates, and find the outlet water temperature corresponding to the current inlet water temperature, the current ambient temperature, the current heating power, and the current coolant flow rate in the outlet water temperature mapping table, and use the found outlet water temperature as the second outlet water temperature T1.

8. A calibration system for the outlet temperature sensor of a water heating electric heater, characterized in that, The system includes: A first temperature sensor disposed at the inlet of the water-heating electric heater, a second temperature sensor disposed at the outlet of the water-heating electric heater, and a processor communicatively connected to the first temperature sensor and the second temperature sensor; The first temperature sensor is used to monitor the inlet water temperature at the inlet of the water-heating electric heater and send it to the processor. The second temperature sensor is used to monitor the outlet water temperature at the inlet of the water-heating electric heater and send it to the processor. The processor calibrates whether the second temperature sensor is invalid based on the method for calibrating the outlet temperature sensor of the water-heating electric heater according to any one of claims 1 to 7.

9. The outlet water temperature sensor calibration system of the water heating and electric heater according to claim 8, characterized in that, The system further includes: A prompting unit communicatively connected to the processor; When it is detected that the second temperature sensor fails, a reminder of the failure of the second temperature sensor is sent through the prompting unit.

10. A new energy vehicle, characterized in that, The new energy vehicle is integrated with the system for calibrating the outlet temperature sensor of the water-heating electric heater according to claim 8 or 9.

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