Flow control method and device based on a PTC heater

Abstract

The present invention provides a flow control method and device based on a PTC heater. The method is applied to a controller of an in-vehicle heating device. The in-vehicle heating device includes a PTC heater, and the controller is communicatively connected to the PTC heater. The method includes: periodically obtaining the temperature difference between the inlet and outlet of the PTC heater and the heating power; inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate; obtaining the output value of the working parameter according to the corresponding relationship between the coolant flow rate and the working parameter stored in advance under different output temperature differences, and controlling the output temperature of the PTC heater according to the output value. The embodiment of the present invention can achieve low-cost calculation of the coolant flow rate and reduce the coolant flow meter assembly; the embodiment of the present invention can also control the output temperature of the PTC heater according to the output value, improving the heating efficiency of the PTC heater.

Description

Technical Field

[0001] The present invention relates to the technical field of PTC heaters, and in particular, to a flow control method and device based on a PTC heater. Background Art

[0002] A PTC (Positive Temperature Coefficient) heater, also known as a PTC heating element, is composed of a PTC ceramic heating element and an aluminum tube. The PTC heater has the advantages of small thermal resistance and high heat exchange efficiency, and is mostly applied in vehicle-mounted systems to provide heat energy for batteries and passengers in low-temperature environments. With the progress of technology, the performance requirements of electronic devices are getting higher and higher. Therefore, how to accurately adjust the output temperature of the PTC heater has become an urgent problem to be solved.

[0003] The output temperature of the PTC heater is affected by factors such as the coolant flow rate. In the prior art, a dedicated flow meter is used to obtain the coolant flow rate, so as to accurately adjust the output temperature of the PTC heater according to the obtained coolant flow rate. However, the flow meter is expensive, and there is a problem of high input cost in using the flow meter to obtain the coolant flow rate.

[0004] Therefore, the existing flow calculation method has the problem of high input cost. Summary of the Invention

[0005] Embodiments of the present invention provide a flow control method and device based on a PTC heater, aiming to solve the problem of high input cost in the existing flow calculation method.

[0006] In a first aspect, embodiments of the present invention provide a flow control method based on a PTC heater. The method is applied to a controller of a vehicle-mounted heating device, the vehicle-mounted heating device includes a PTC heater, and the controller is communicatively connected to the PTC heater. The method includes:

[0007] Regularly obtain the temperature difference between the inlet and outlet of the PTC heater and the heating power;

[0008] Input the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate;

[0009] According to the pre-stored correspondence between the coolant flow rate and the working parameters at different output temperature differences, obtain the output value of the working parameters to control the output temperature of the PTC heater according to the output value.

[0010] Second aspect, an embodiment of the present invention further provides a flow control device based on a PTC heater. The device is configured in a controller of a vehicle heating device, the vehicle heating device includes a PTC heater, the controller is communicatively connected to the PTC heater, and the device includes:

[0011] An acquisition unit, configured to periodically acquire the temperature difference between the inlet and outlet of the PTC heater and the heating power;

[0012] A calculation unit, configured to input the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula, and calculate and obtain the corresponding coolant flow rate;

[0013] A control unit, configured to obtain the output value of the working parameter according to the corresponding relationship between the coolant flow rate and the working parameter stored in advance under different output temperature differences, and control the output temperature of the PTC heater according to the output value.

[0014] The present invention provides a flow control method and device based on a PTC heater. The method is applied to a controller of a vehicle heating device. The vehicle heating device includes a PTC heater, and the controller is communicatively connected to the PTC heater. The method includes: periodically acquiring the temperature difference between the inlet and outlet of the PTC heater and the heating power; inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula, and calculating and obtaining the corresponding coolant flow rate; obtaining the output value of the working parameter according to the corresponding relationship between the coolant flow rate and the working parameter stored in advance under different output temperature differences, and controlling the output temperature of the PTC heater according to the output value. Embodiments of the present invention can calculate and obtain the corresponding coolant flow rate by inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula, thereby realizing low-cost calculation of the coolant flow rate; further, compared with using a dedicated flow meter to obtain the coolant flow rate in the prior art, embodiments of the present invention can reduce the coolant flow meter assembly and reduce the coolant flow calculation cost; embodiments of the present invention can also obtain the output value of the working parameter according to the corresponding relationship between the coolant flow rate and the working parameter stored in advance under different output temperature differences, and control the output temperature of the PTC heater according to the output value, so as to realize precise control of the output temperature of the PTC heater, improve the heating efficiency of the PTC heater, make the real-time output temperature of the PTC heater reach the target output temperature as fast as possible, ensure the stability of the real-time output temperature, and meet the heating requirements. Description of the Drawings

[0015] To more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0016] Figure 1 FIG. is a schematic flowchart of a flow control method based on a PTC heater provided by an embodiment of the present invention;

[0017] Figure 2 FIG. is a schematic block diagram of a flow control device based on a PTC heater provided by an embodiment of the present invention. Detailed Embodiments

[0018] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention.

[0019] It should be understood that when used in this specification and the appended claims, the terms "comprises" and "comprising" indicate the presence of the described features, wholes, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, wholes, steps, operations, elements, components, and / or their combinations.

[0020] It should also be understood that the terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. As used in this specification of the present invention and the appended claims, unless the context clearly indicates otherwise, the singular forms "a", "an", and "the" are intended to include the plural forms.

[0021] It should be further understood that the term "and / or" used in this specification of the present invention and the appended claims refers to any combination and all possible combinations of one or more of the associated listed items, and includes these combinations. Embodiments of the present invention provide a flow control method and device based on a PTC heater. The flow control method based on a PTC heater is shown in Figure 1 , Figure 1 FIG. is a schematic flowchart of a flow control method based on a PTC heater provided by an embodiment of the present invention. The method is applied to a controller of an in-vehicle heating device, the in-vehicle heating device includes a PTC heater, and the controller is communicatively connected to the PTC heater.

[0022] Figure 1 This is a schematic flowchart of the flow control method based on a PTC heater provided by an embodiment of the present invention. As Figure 1 shown, the method includes steps S110 - S130.

[0023] S110. Regularly obtain the temperature difference between the inlet and outlet of the PTC heater and the heating power.

[0024] In this embodiment, the vehicle heating system includes a PTC heater, a water pump, and a circulation pipeline. The PTC heater is connected to the water pump through the circulation pipeline; the circulation pipeline contains coolant; the water pump is used to drive the movement of the coolant; the PTC heater is used to heat the coolant.

[0025] Regularly obtain the temperature difference between the inlet and outlet of the PTC heater and the heating power; specifically, obtain the temperature difference between the inlet and outlet of the PTC heater and the heating power every preset duration. The preset duration can be set according to actual applications and can be set to 100 microseconds.

[0026] The heating power is the power value output by the PTC heater itself, and the power value is an effective power value. The heating power is obtained based on the theoretical heating power and heating efficiency of the PTC heater; for example, if the theoretical heating power of the PTC heater is 7KW and the heating efficiency is 95%, then the heating power Q of the PTC heater is 6.65KW. The specific calculation formula is: Q = (7×0.95) KW = 6.65KW. Additionally, the heating power can also be calculated by detecting the actual voltage value and actual current value of the PTC heater and based on the actual voltage value and the actual current value.

[0027] Furthermore, a temperature sensor can be used to obtain the temperature difference between the inlet and outlet of the PTC heater; where the temperature difference between the inlet and outlet = | the coolant temperature at the inlet of the PTC heater - the coolant temperature at the outlet of the PTC heater |.

[0028] In one embodiment, step S110 includes: regularly obtaining the first coolant temperature collected by the first temperature sensor and the second coolant temperature collected by the second temperature sensor; where the first temperature sensor is arranged at the inlet of the PTC heater, and the second temperature sensor is arranged at the outlet of the PTC heater; taking the difference between the first coolant temperature and the second coolant temperature as the temperature difference between the inlet and outlet.

[0029] In this embodiment, the first temperature sensor acquires the coolant temperature at the water inlet of the PTC heater and provides it to the controller; the second temperature sensor acquires the coolant temperature at the water outlet of the PTC heater and provides it to the controller; the controller can calculate the inlet and outlet temperature difference based on the first coolant temperature and the second coolant temperature.

[0030] S120. Input the performance parameters of the coolant, the heating power, and the inlet and outlet temperature difference into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate.

[0031] In this embodiment, the performance parameters of the coolant, the heating power Q, and the inlet and outlet temperature difference are input into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate Vs; the performance parameters of the coolant are from the coolant supplier, and the performance parameters include data such as the constant pressure specific heat capacity Cp and the specific weight r of the coolant; specifically, the coolant can be a 50% ethylene glycol solution, the constant pressure specific heat capacity of the 50% ethylene glycol solution is about 3.5 KJ / Kg·°C, and the specific weight of the 50% ethylene glycol solution is about 1113 Kg / m 3 .

[0032] The flow calculation formula is: ; where Vs is the coolant flow rate, Q is the heating power, Cp is the constant pressure specific heat capacity, r is the specific weight, is the inlet and outlet temperature difference.

[0033] In the embodiment of the present invention, by inputting the performance parameters of the coolant, the heating power, and the inlet and outlet temperature difference into a preset flow calculation formula, the corresponding coolant flow rate can be calculated and obtained, realizing the low-cost calculation of the coolant flow rate; further, compared with using a dedicated flow meter to obtain the coolant flow rate in the prior art, the embodiment of the present invention can reduce the coolant flow meter assembly and reduce the coolant flow rate calculation cost.

[0034] In one embodiment, before step S120, it further includes: performing unit conversion on the performance parameters and / or the heating power according to the target measurement unit.

[0035] In this embodiment, before inputting the performance parameters of the coolant, the heating power, and the inlet and outlet temperature difference into a preset flow calculation formula, it is also necessary to perform unit conversion on the performance parameters and / or the heating power according to the target measurement unit; the target measurement unit can be the measurement unit of the coolant flow rate, and the target measurement unit can be set to m 3 / h; for example, the heating power of the PTC heater is 6.65 KW. At this time, the measurement unit of the heating power does not match the target measurement unit. Therefore, unit conversion needs to be performed according to the target measurement unit m 3 / h. The specific conversion formula is: Q = 6.65 × 3600 KJ / h = 23940 KJ / h; where Q is the heating power.

[0036] In one embodiment, after step S120, it further includes: determining the target coolant flow rate of the PTC heater, obtaining multiple coolant flow rates within a preset statistical period and calculating the average value to obtain the target coolant flow rate.

[0037] In this embodiment, in order to precisely adjust the output temperature of the PTC heater, the rotation speed of the water pump can be dynamically adjusted according to the target coolant flow rate; among them, the coolant flow rate can be adjusted by adjusting the rotation speed of the water pump, and the output temperature of the PTC heater can be adjusted by adjusting the coolant flow rate; the target coolant flow rate is the average value of multiple coolant flow rates within a preset statistical period; the statistical period can be set according to actual applications, where the statistical period is greater than the preset duration, the statistical period is an integer multiple of the preset duration, and the statistical period can be set to 1 second.

[0038] In one embodiment, after step S120, it further includes: determining whether the coolant flow rate is within a preset flow rate range; if it is not within the preset flow rate range, outputting a corresponding flow rate anomaly prompt message.

[0039] In this embodiment, it is determined whether the coolant flow rate is within a preset flow rate range; the preset flow rate range can be set according to actual applications; if it is within the preset flow rate range, the rotation speed of the water pump is dynamically adjusted according to the coolant flow rate; specifically, the rotation speed of the water pump can be dynamically adjusted according to the set output temperature and the coolant flow rate; among them, the coolant flow rate can be adjusted by adjusting the rotation speed of the water pump, and the output temperature of the PTC heater can be adjusted by adjusting the coolant flow rate, so as to achieve precise control of the output temperature of the PTC heater and meet the heating requirements.

[0040] If it is not within the preset flow rate range, output a corresponding flow rate anomaly prompt message, and the flow rate anomaly prompt message can be "Coolant flow rate anomaly", etc.; specifically, display the flow rate anomaly prompt message on a specified interface to prompt the user.

[0041] In one embodiment, after determining whether the coolant flow rate is within a preset flow rate range, the method further includes: if it is not within the preset flow rate range, determining whether the coolant flow rate is greater than a preset flow rate threshold; if so, outputting a first abnormal prompt message; if not, outputting a second abnormal prompt message and / or controlling the PTC heater to stop heating.

[0042] In this embodiment, if the coolant flow rate is not within the preset flow rate range, it is determined whether the coolant flow rate is greater than a preset flow rate threshold; the preset flow rate threshold is greater than or equal to the maximum value in the preset flow rate range, and the preset flow rate threshold can be set according to actual applications; when the coolant flow rate is greater than the preset flow rate threshold, the coolant pressure in the circulation pipeline is high, which easily causes device damage. At this time, a first abnormal prompt message is output to prompt the user, and the user can adjust the speed of the water pump or turn off the PTC heater according to the first abnormal prompt message; the first abnormal prompt message can be "The pipeline pressure is high, please adjust or turn off the PTC heater, etc.".

[0043] When the coolant flow rate is not within the preset flow rate range and is not greater than the preset flow rate threshold, it is determined that the PTC heater is in a dry burning state. To prevent device damage, it is necessary to output a second abnormal prompt message and / or control the PTC heater to stop heating; wherein, the second abnormal prompt message is "The PTC heater is dry burning, please turn off the PTC heater or supplement the coolant".

[0044] In one embodiment, after step S120, the method further includes: obtaining a theoretical coolant flow rate according to the operating parameters and characteristic data of the water pump; determining whether the difference between the coolant flow rate and the theoretical coolant flow rate is within a preset difference range; if it is not within the preset difference range, outputting a third abnormal prompt message.

[0045] In this embodiment, a theoretical coolant flow rate is obtained according to the operating parameters and characteristic data of the water pump; determining whether the difference between the coolant flow rate and the theoretical coolant flow rate is within a preset difference range; if it is within the preset difference range, perform subsequent operations, for example, dynamically adjusting the speed of the water pump according to the coolant flow rate, or obtaining a coolant flow rate compensation value according to the difference, and dynamically adjusting the speed of the water pump according to the coolant flow rate compensation value and the coolant flow rate.

[0046] If it is not within the preset difference range, it indicates that the coolant in the circulation pipeline is insufficient, and a third abnormal prompt message is output to prompt the user. The third abnormal prompt message can be "The coolant is insufficient, please supplement it", etc.

[0047] S130. Obtain the output value of the working parameter according to the pre-stored corresponding relationship between the coolant flow rate and the working parameter at different output temperature differences, and control the output temperature of the PTC heater according to the output value.

[0048] In this embodiment, the controller is communicatively connected to the vehicle control end of the whole vehicle; specifically, the vehicle controller is communicatively connected to the controller through a LIN transceiver and a digital isolation chip, and the signal or energy transfer between the vehicle controller and the controller is realized by using the LIN transceiver and the digital isolation chip; before obtaining the output value of the working parameter according to the pre-stored corresponding relationship between the coolant flow rate and the working parameter at different output temperature differences, it is necessary to obtain the target output temperature from the vehicle controller in real time or at regular intervals; wherein, the target output temperature is the output temperature of the PTC heater set by the vehicle controller; at the same time, a temperature sensor is used to collect the real-time output temperature of the PTC heater in real time; calculate the output temperature difference according to the target output temperature and the real-time output temperature; obtain the output value of the working parameter according to the pre-stored corresponding relationship between the coolant flow rate and the working parameter at different output temperature differences; adjust the rotation speed of the water pump according to the output value, so as to realize the dynamic adjustment of the rotation speed of the water pump according to the coolant flow rate, and indirectly realize the precise control of the output temperature of the PTC heater, improve the heating efficiency of the PTC heater, make the real-time output temperature of the PTC heater reach the target output temperature as fast as possible, ensure the stability of the real-time output temperature, and meet the heating requirements; for example, if the output temperature difference is greater than the preset maximum threshold of the output temperature difference, obtain the output value of the working parameter according to the pre-stored corresponding relationship between the coolant flow rate and the working parameter at different output temperature differences, and adjust the rotation speed of the water pump according to the output value. When adjusting the rotation speed of the water pump according to the output value, the heating efficiency of the PTC heater reaches the highest; further, in order to make the real-time output temperature of the PTC heater reach the target output temperature as fast as possible, while adjusting the rotation speed of the water pump, the heating power of the PTC heater can also be dynamically adjusted according to the output temperature difference to improve the heating efficiency of the PTC heater.

[0049] In summary, embodiments of the present invention can calculate and obtain the corresponding coolant flow rate by inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow rate calculation formula, thereby realizing the low-cost calculation of the coolant flow rate. Further, compared with the prior art in which a dedicated flow meter is used to obtain the coolant flow rate, embodiments of the present invention can reduce the coolant flow meter assembly and lower the cost of calculating the coolant flow rate. Embodiments of the present invention can also obtain the output value of the working parameter according to the corresponding relationship between the coolant flow rate and the working parameter stored in advance under different output temperature differences, and control the output temperature of the PTC heater according to the output value, so as to achieve precise control of the output temperature of the PTC heater, improve the heating efficiency of the PTC heater, make the real-time output temperature of the PTC heater reach the target output temperature as quickly as possible, ensure the stability of the real-time output temperature, and meet the heating requirements.

[0050] Figure 2 FIG. is a schematic block diagram of a flow control device based on a PTC heater provided by an embodiment of the present invention. As Figure 2 shown, corresponding to the above flow control method based on a PTC heater, the present invention also provides a flow control device based on a PTC heater. The device is configured in a controller of a vehicle heating device, and the vehicle heating device includes a PTC heater. The controller is communicatively connected to the PTC heater. Specifically, please refer to Figure 2 , the flow control device 700 based on a PTC heater includes:

[0051] An acquisition unit 701, configured to periodically acquire the temperature difference between the inlet and outlet of the PTC heater and the heating power.

[0052] In this embodiment, the vehicle heating system includes a PTC heater, a water pump, and a circulation pipeline. The PTC heater is connected to the water pump through the circulation pipeline; the circulation pipeline contains coolant; the water pump is used to drive the movement of the coolant; the PTC heater is used to heat the coolant.

[0053] Periodically acquire the temperature difference between the inlet and outlet of the PTC heater and the heating power; specifically, acquire the temperature difference between the inlet and outlet of the PTC heater and the heating power every preset time period. The preset time period can be set according to actual applications, and the preset time period can be set to 100 microseconds.

[0054] The heating power is the power value output by the PTC heater itself, and the power value is the effective power value. The heating power is obtained based on the theoretical heating power and heating efficiency of the PTC heater. For example, if the theoretical heating power of the PTC heater is 7KW and the heating efficiency is 95%, then the heating power Q of the PTC heater is 6.65KW. The specific calculation formula is: Q = (7×0.95) KW = 6.65KW. In addition, the heating power can also be calculated by detecting the actual voltage value and actual current value of the PTC heater and according to the actual voltage value and the actual current value.

[0055] Further, a temperature sensor can be used to obtain the temperature difference between the inlet and outlet of the PTC heater; where the temperature difference between the inlet and outlet = | the coolant temperature at the inlet of the PTC heater - the coolant temperature at the outlet of the PTC heater |.

[0056] The calculation unit 702 is configured to input the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate.

[0057] In this embodiment, the performance parameters of the coolant, the heating power Q, and the temperature difference between the inlet and outlet are input into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate Vs; the performance parameters of the coolant come from the coolant supplier, and the performance parameters include data such as the constant pressure specific heat capacity Cp and specific weight r of the coolant; specifically, the coolant can be a 50% ethylene glycol solution. The constant pressure specific heat capacity of the 50% ethylene glycol solution is about 3.5 KJ / Kg·°C, and the specific weight of the 50% ethylene glycol solution is about 1113 Kg / m 3 .

[0058] The flow calculation formula is: ; where Vs is the coolant flow rate, Q is the heating power, Cp is the constant pressure specific heat capacity, r is the specific weight, is the temperature difference between the inlet and outlet.

[0059] In the embodiment of the present invention, the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet can be input into a preset flow calculation formula to calculate and obtain the corresponding coolant flow rate, so as to realize low-cost calculation of the coolant flow rate; further, compared with using a dedicated flow meter to obtain the coolant flow rate in the prior art, the embodiment of the present invention can reduce the coolant flow meter assembly and reduce the coolant flow rate calculation cost.

[0060] A control unit 703 is configured to obtain an output value of the working parameter according to a pre-stored correspondence between the coolant flow rate and the working parameter at different output temperature differences, and control the output temperature of the PTC heater according to the output value.

[0061] In this embodiment, the controller is communicatively connected to a vehicle control terminal of the whole vehicle; specifically, the vehicle controller is communicatively connected to the controller through a LIN transceiver and a digital isolation chip, and the LIN transceiver and the digital isolation chip are used to realize the transmission of signals or energy between the vehicle controller and the controller; before obtaining the output value of the working parameter according to the pre-stored correspondence between the coolant flow rate and the working parameter at different output temperature differences, it is necessary to obtain the target output temperature from the vehicle controller in real time or at regular intervals; wherein, the target output temperature is the output temperature of the PTC heater set by the vehicle controller; at the same time, a temperature sensor is used to collect the real-time output temperature of the PTC heater in real time; the output temperature difference is calculated according to the target output temperature and the real-time output temperature; the output value of the working parameter is obtained according to the pre-stored correspondence between the coolant flow rate and the working parameter at different output temperature differences; the rotation speed of the water pump is adjusted according to the output value, so as to realize the dynamic adjustment of the rotation speed of the water pump according to the coolant flow rate, and indirectly realize the precise control of the output temperature of the PTC heater, improve the heating efficiency of the PTC heater, make the real-time output temperature of the PTC heater reach the target output temperature as fast as possible, ensure the stability of the real-time output temperature, and meet the heating requirements; for example, if the output temperature difference is greater than a preset maximum threshold of the output temperature difference, the output value of the working parameter is obtained according to the pre-stored correspondence between the coolant flow rate and the working parameter at different output temperature differences, and the rotation speed of the water pump is adjusted according to the output value. When the rotation speed of the water pump is adjusted according to the output value, the heating efficiency of the PTC heater reaches the highest; further, in order to make the real-time output temperature of the PTC heater reach the target output temperature as fast as possible, while adjusting the rotation speed of the water pump, the heating power of the PTC heater can also be dynamically adjusted according to the output temperature difference to improve the heating efficiency of the PTC heater.

[0062] In some embodiments, the calculation unit 702 is further configured to:

[0063] Determine the target coolant flow rate of the PTC heater, where the target coolant flow rate is the average value of multiple coolant flow rates within a preset statistical period.

[0064] In this embodiment, in order to precisely adjust the output temperature of the PTC heater, the rotational speed of the water pump can be dynamically adjusted according to the target coolant flow rate; wherein, the coolant flow rate can be adjusted by adjusting the rotational speed of the water pump, and the output temperature of the PTC heater can be adjusted by adjusting the coolant flow rate; the target coolant flow rate is the average value of multiple coolant flow rates within a preset statistical period; the statistical period can be set according to actual applications, wherein, the statistical period is greater than the preset duration, the statistical period is an integer multiple of the preset duration, and the statistical period can be set to 1 second.

[0065] In some embodiments, the calculation unit 702 is further configured to:

[0066] Determine whether the coolant flow rate is within a preset flow rate range; if it is not within the preset flow rate range, output a corresponding flow rate anomaly prompt message.

[0067] In this embodiment, determine whether the coolant flow rate is within a preset flow rate range; the preset flow rate range can be set according to actual applications; if it is within the preset flow rate range, dynamically adjust the rotational speed of the water pump according to the coolant flow rate; specifically, the rotational speed of the water pump can be dynamically adjusted according to the set output temperature and the coolant flow rate; wherein, the coolant flow rate can be adjusted by adjusting the rotational speed of the water pump, and the output temperature of the PTC heater can be adjusted by adjusting the coolant flow rate, so as to achieve precise control of the output temperature of the PTC heater and meet the heating requirements.

[0068] If it is not within the preset flow rate range, output a corresponding flow rate anomaly prompt message, and the flow rate anomaly prompt message can be "coolant flow rate anomaly", etc.; specifically, display the flow rate anomaly prompt message on a specified interface to prompt the user.

[0069] In some embodiments, after the calculation unit 702 executes the step of determining whether the coolant flow rate is within a preset flow rate range, it is further configured to:

[0070] If it is not within the preset flow rate range, then determine whether the coolant flow rate is greater than a preset flow rate threshold; if so, output a first anomaly prompt message; if not, output a second anomaly prompt message and / or control the PTC heater to stop heating.

[0071] In this embodiment, if the coolant flow rate is not within the preset flow rate range, it is determined whether the coolant flow rate is greater than a preset flow rate threshold; the preset flow rate threshold is greater than or equal to the maximum value in the preset flow rate range, and the preset flow rate threshold can be set according to actual applications; when the coolant flow rate is greater than the preset flow rate threshold, the coolant pressure in the circulation pipeline is high, which is likely to cause device damage. At this time, a first abnormal prompt message is output to prompt the user, and the user can adjust the speed of the water pump down or turn off the PTC heater according to the first abnormal prompt message; the first abnormal prompt message can be "High pipeline pressure, please adjust down or turn off the PTC heater, etc.".

[0072] When the coolant flow rate is not within the preset flow rate range and is not greater than the preset flow rate threshold, it is determined that the PTC heater is in a dry burning state. To prevent device damage, a second abnormal prompt message needs to be output and / or the PTC heater is controlled to stop heating; wherein, the second abnormal prompt message is "The PTC heater is dry burning, please turn off the PTC heater or supplement the coolant".

[0073] In some embodiments, after the calculation unit 702 executes the step of calculating to obtain the corresponding coolant flow rate, it is further used for:

[0074] Obtain the theoretical coolant flow rate according to the operating parameters and characteristic data of the water pump; determine whether the difference between the coolant flow rate and the theoretical coolant flow rate is within a preset difference range; if it is not within the preset difference range, output a third abnormal prompt message.

[0075] In this embodiment, obtain the theoretical coolant flow rate according to the operating parameters and characteristic data of the water pump; determine whether the difference between the coolant flow rate and the theoretical coolant flow rate is within a preset difference range; if it is within the preset difference range, perform subsequent operations, for example, dynamically adjust the speed of the water pump according to the coolant flow rate, or obtain a coolant flow rate compensation value according to the difference, and dynamically adjust the speed of the water pump according to the coolant flow rate compensation value and the coolant flow rate.

[0076] If it is not within the preset difference range, it means that the coolant in the circulation pipeline is insufficient, and a third abnormal prompt message is output to prompt the user. The third abnormal prompt message can be "Insufficient coolant, please supplement", etc.

[0077] In some embodiments, before the calculation unit 702 executes the step of inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow rate calculation formula, it is further used for:

[0078] Perform unit conversion on the performance parameters and / or the heating power according to the target measurement unit.

[0079] In this embodiment, before inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow calculation formula, it is also necessary to perform unit conversion on the performance parameters and / or the heating power according to the target measurement unit; the target measurement unit can be the measurement unit of the coolant flow rate, and the target measurement unit can be set to m 3 / h; for example, the heating power of the PTC heater is 6.65 KW. At this time, the measurement unit of the heating power does not match the target measurement unit. Therefore, it is necessary to perform unit conversion on it according to the target measurement unit m 3 / h. The specific conversion formula is: Q = 6.65×3600 KJ / h = 23940 KJ / h; where Q is the heating power.

[0080] In some embodiments, when the obtaining unit 701 executes the step of periodically obtaining the temperature difference between the inlet and outlet of the PTC heater, it is specifically configured to:

[0081] Periodically obtain the first coolant temperature collected by the first temperature sensor and the second coolant temperature collected by the second temperature sensor; wherein, the first temperature sensor is arranged at the water inlet of the PTC heater, and the second temperature sensor is arranged at the water outlet of the PTC heater; the difference between the first coolant temperature and the second coolant temperature is used as the temperature difference between the inlet and outlet.

[0082] In this embodiment, the first temperature sensor obtains the coolant temperature at the water inlet of the PTC heater and provides it to the controller; the second temperature sensor obtains the coolant temperature at the water outlet of the PTC heater and provides it to the controller; the controller can calculate the temperature difference between the inlet and outlet according to the first coolant temperature and the second coolant temperature.

[0083] In summary, embodiments of the present invention can calculate and obtain the corresponding coolant flow rate by inputting the performance parameters of the coolant, the heating power, and the temperature difference between the inlet and outlet into a preset flow rate calculation formula, thereby achieving low-cost calculation of the coolant flow rate. Further, compared with using a dedicated flow meter to obtain the coolant flow rate in the prior art, embodiments of the present invention can reduce the coolant flow meter assembly and lower the cost of calculating the coolant flow rate. Embodiments of the present invention can also obtain the output value of the working parameter according to the corresponding relationship between the coolant flow rate and the working parameter stored in advance under different output temperature differences, and control the output temperature of the PTC heater according to the output value, so as to achieve precise control of the output temperature of the PTC heater, improve the heating efficiency of the PTC heater, make the real-time output temperature of the PTC heater reach the target output temperature as quickly as possible, ensure the stability of the real-time output temperature, and meet the heating requirements.

[0084] As described above, the above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention can easily think of various equivalent modifications or substitutions, and these modifications or substitutions should all be covered within the protection scope of the present invention. Therefore, the protection scope of the present invention shall be subject to the protection scope of the claims.

Claims

1. A flow control method based on a PTC heater, characterized in that: The method is applied to a controller of a vehicle-mounted heating device, the vehicle-mounted heating device includes a PTC heater, the controller is communicatively connected with the PTC heater, and the method includes: The inlet and outlet temperature difference and heating power of the PTC heater are obtained regularly; the heating power is the power value output by the PTC heater itself, and the power value is the effective power value; The performance parameters of the coolant, the heating power and the inlet and outlet temperature difference are input into a preset flow calculation formula to calculate the corresponding coolant flow; the flow calculation formula is: ; Where Vs is the coolant flow rate, Q is the heating power, Cp is the constant pressure specific heat capacity, r is the specific weight, is the inlet and outlet temperature difference; According to the pre-stored correspondence between the coolant flow rate and the working parameter at different output temperature differences, an output value of the working parameter is obtained to control the output temperature of the PTC heater according to the output value; After the calculation to obtain the corresponding coolant flow rate, the method further includes: The target coolant flow rate of the PTC heater is determined, and a plurality of coolant flow rates within a preset statistical period are acquired and an average is calculated to obtain the target coolant flow rate.

2. The flow control method based on the PTC heater according to claim 1, characterized in that: After the calculation to obtain the corresponding coolant flow rate, the method further includes: Determining whether the coolant flow rate is within a preset flow rate range; If it is not within the preset flow rate range, the corresponding flow abnormality prompt information is output.

3. The flow control method based on the PTC heater according to claim 2, characterized in that: After determining whether the coolant flow rate is within a preset flow rate range, the method further includes: If it is not within the preset flow range, determining whether the coolant flow is greater than a preset flow threshold; If yes, output the first abnormal prompt information; If not, a second abnormal prompt message is output and / or the PTC heater is controlled to stop heating.

4. The flow control method based on a PTC heater according to claim 1, characterized in that: After the calculation to obtain the corresponding coolant flow rate, the method further includes: Obtain theoretical coolant flow rate based on the operating parameters and characteristic data of the water pump; Determining whether a difference between the coolant flow rate and the theoretical coolant flow rate is within a preset difference range; If it is not within the preset difference range, a third abnormal prompt information is output.

5. The flow control method based on PTC heater according to claim 1, characterized in that: Before inputting the performance parameters of the coolant, the heating power and the inlet and outlet temperature difference into the preset flow calculation formula, the method further includes: The performance parameter and / or the heating power is / are converted into units according to a target measurement unit.

6. The flow control method based on PTC heater according to claim 1, characterized in that: The step of regularly obtaining the inlet and outlet temperature difference of the PTC heater includes: Regularly acquiring a first coolant temperature collected by a first temperature sensor and a second coolant temperature collected by a second temperature sensor; wherein the first temperature sensor is arranged at a water inlet of the PTC heater, and the second temperature sensor is arranged at a water outlet of the PTC heater; The difference between the first coolant temperature and the second coolant temperature is used as the inlet and outlet temperature difference.

7. A flow control device based on a PTC heater, characterized in that: The device is configured in a controller of a vehicle-mounted heating device, the vehicle-mounted heating device includes a PTC heater, the controller is communicatively connected with the PTC heater, and the device includes: An acquisition unit, used for regularly acquiring the inlet and outlet temperature difference and heating power of the PTC heater; the heating power is the power value output by the PTC heater itself, and the power value is an effective power value; The calculation unit is used to input the performance parameters of the coolant, the heating power and the inlet and outlet temperature difference into a preset flow calculation formula to calculate the corresponding coolant flow; the flow calculation formula is: ; Where Vs is the coolant flow rate, Q is the heating power, Cp is the constant pressure specific heat capacity, r is the specific weight, is the inlet and outlet temperature difference; A control unit, for obtaining an output value of the operating parameter according to a pre-stored correspondence between a coolant flow rate and an operating parameter at different output temperature differences, so as to control the output temperature of the PTC heater according to the output value; The computing unit is also used for: The target coolant flow rate of the PTC heater is determined, and a plurality of coolant flow rates within a preset statistical period are acquired and an average is calculated to obtain the target coolant flow rate.

8. The flow control device based on a PTC heater according to claim 7, characterized in that: The computing unit is also used for: Determining whether the coolant flow rate is within a preset flow rate range; If it is not within the preset flow rate range, the corresponding flow abnormality prompt information is output.

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