Water pump control method and system of electric vehicle and vehicle

Abstract

The invention discloses a water pump control method and system of an electric vehicle and the vehicle, and belongs to the field of electric vehicle heat management. The method comprises the steps that the actual temperature of a plurality of to-be-cooled parts and the current duty ratio of a water pump are obtained; determining a target duty ratio of the water pump based on each actual temperature; according to the target duty ratio of the water pump and the current duty ratio of the water pump, determining the duty ratio lifting demand of the water pump; if the demand is the rising demand, executing a first control strategy, obtaining an updated water pump duty ratio, and calculating an output quantity; if so, executing a second control strategy to obtain an updated water pump duty ratio and calculate an output quantity; and controlling the water pump according to the output quantity. According to the method, stable change of the duty ratio of the water pump can be maintained, the problem that parts such as pipelines are damaged due to sudden increase of water pressure caused by great increase or decrease of water flow is solved, the service life of a cooling system is prolonged, a water pressure sensor does not need to be additionally arranged, and the vehicle cost is reduced.

Description

Technical Field

[0001] The present application belongs to the technical field of thermal management of electric vehicles, and specifically relates to a water pump control method, system and vehicle for an electric vehicle. Background Art

[0002] Electric vehicles all have a thermal management system, one of the core components of which is the water pump. When the water pump is turned on, the cooling flow rate will suddenly increase significantly, which will cause a sudden increase in water pressure and impact on the pipe wall, water pump, valve, etc. in the water channel. The sudden increase in water pressure is caused by the inertia of water or other coolants. This situation is called the "water hammer effect". Similarly, when the water pump is turned off, the cooling flow rate will suddenly decrease significantly, causing a sudden increase in water pressure.

[0003] At present, the control of the water pump in the thermal management system of electric vehicles is generally based on temperature, without considering the influence of the internal pressure of the water circuit. When the power is on, the vehicle controller sets the corresponding duty cycle according to the temperature of each component in the water circuit, and the water pump executes the duty cycle request sent by the vehicle controller. When the power is off, the vehicle controller disconnects the power supply of the water pump and the water pump stops working.

[0004] This control method leads to the following problems: (1) Due to the long-term pressure shock caused by the large change in flow rate, the components in the water circulation will work under harsh conditions. Excessive water pressure will reduce the durability of components such as water pipes, water pumps, and cause damage to the pipelines; (2) If it is necessary to additionally measure the pressure inside the water circuit, the vehicle needs to install a pressure sensor in the water circuit, which increases the cost of the vehicle. Summary of the invention

[0005] The purpose of the embodiments of the present application is to provide a water pump control method, system and vehicle for an electric vehicle, which can solve the problem of sudden increase in water pressure causing damage to pipelines and other components due to the opening or closing of the water pump or a substantial increase or decrease in water flow, control the water flow to change smoothly, and the vehicle does not need to be equipped with a pressure sensor, thereby reducing the cost of the vehicle.

[0006] In order to solve the above technical problems, this application is implemented as follows: In a first aspect, an embodiment of the present application provides a water pump control method for an electric vehicle, which is applied to a thermal management system, wherein the thermal management system includes a water pipeline, a water pump, and a plurality of components to be cooled. The method includes: Obtain the actual temperature of multiple components to be cooled and the current duty cycle of the water pump; determining a target duty cycle of the water pump based on each actual temperature; Determine the duty cycle requirement of the water pump according to the target duty cycle of the water pump and the current duty cycle of the water pump; If it is an increasing demand, the first control strategy is executed to obtain the updated duty cycle of the water pump and calculate the output; If it is a decreasing demand, the second control strategy is executed to obtain the updated duty cycle of the water pump and calculate the output; The water pump is controlled according to the output.

[0007] Optionally, if the demand is rising, executing the first control strategy, obtaining the updated water pump duty cycle and calculating the output, the first control strategy in the step includes: Step S201, defining the threshold range of the water pump duty cycle x and the increase adjustment amount y of the current water pump duty cycle, where 0%≤x≤90%; Step S202, dividing the threshold range into a first threshold range a1, a second threshold range b1, a third threshold range c1 and a fourth threshold range d1 in ascending order, which correspond to the first gradient value, the second gradient value, the third gradient value and the fourth gradient value of the rising adjustment amount y of the current duty cycle of the water pump respectively; Step S203, determining a threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S204, determining the gradient value of the rising adjustment amount y according to the threshold range; Step S205, adjusting the current duty cycle of the water pump upward according to the gradient value to obtain an updated duty cycle of the water pump; Step S206, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; Step S207: if not, the updated water pump duty cycle is used as the current water pump duty cycle, and steps S203 to S206 are repeated; Step S208: If yes, output the updated water pump duty cycle.

[0008] By subdividing the duty cycle range, the rising adjustment amount of the duty cycle can be controlled more finely to achieve a smoother rising adjustment effect.

[0009] Optionally, in step S202 of the first strategy: The first threshold range a1 is: 0≤a1<20%, ​​and the corresponding first gradient value is: 10; The second threshold range b1 is: 20%≤b1<40%, and the corresponding second gradient value is: 2; The third threshold range c1 is: 40%≤c1<70%, and the corresponding third gradient value is: 5; The fourth threshold range d1 is: 70%≤d1≤90%, and the corresponding fourth gradient value is: 10.

[0010] Different sub-ranges correspond to different adjustment rising gradients, which can be adjusted according to actual conditions to achieve better control effects.

[0011] Optionally, if the demand is decreasing, executing the second control strategy, obtaining the updated water pump duty cycle and calculating the output, the second control strategy in the step includes: Step S301, defining the threshold range of the water pump duty cycle x1 and the downward adjustment amount y1 of the current water pump duty cycle, where 90% ≥ x1 ≥ 0%; Step S302, dividing the threshold range into a fifth threshold range a2, a sixth threshold range b2, a seventh threshold range c2 and an eighth threshold range d2 in descending order, which respectively correspond to the fifth gradient value, the sixth gradient value, the seventh gradient value and the eighth gradient value of the downward adjustment amount y1 of the current duty cycle of the water pump; Step S303, determining a threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S304, determining the gradient value of the downward adjustment amount y1 according to the threshold range; Step S305, adjusting the current duty cycle of the water pump downward according to the gradient value to obtain an updated duty cycle of the water pump; Step S306, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; Step S307: if not, the updated water pump duty cycle is used as the current water pump duty cycle, and steps S303 to S306 are repeated; Step S308: If yes, output the updated water pump duty cycle.

[0012] By subdividing the duty cycle range, the duty cycle down-regulation amount can be controlled more finely, achieving a smoother down-regulation effect.

[0013] Optionally, in step S302 of the second strategy: The fifth threshold range a2 is: 90%≥a2>60%, and the corresponding fifth gradient value is: 10; The sixth threshold range b2 is: 60% ≥ b2 > 40%, and the corresponding sixth gradient value is: 5; The seventh threshold range c2 is: 40% ≥ c2 > 10%, and the corresponding seventh gradient value is: 2; The eighth threshold range d2 is: 10%≥d2≥0%, and the corresponding eighth gradient value is: 5.

[0014] Different sub-ranges correspond to different adjustment descent gradients, which can be adjusted according to actual conditions to achieve better control effects.

[0015] Optionally, the step of determining a target duty cycle of the water pump based on each actual temperature specifically includes: Determining a threshold temperature level of the component to be cooled by presetting a threshold temperature of the component to be cooled; determining a water pump duty cycle based on a threshold temperature level; Compare the actual temperature of each component to be cooled with the preset threshold temperature to obtain the preset threshold temperature level corresponding to each actual temperature; Obtaining a one-to-one corresponding water pump duty cycle based on the obtained multiple preset threshold temperature levels; Multiple water pump duty cycles are compared, and the maximum water pump duty cycle is selected as the water pump target duty cycle.

[0016] By screening out the maximum value of the water pump duty cycle as the water pump target duty cycle, the water pump target duty cycle can meet the cooling requirements of all components to be cooled.

[0017] Optionally, the step of obtaining actual temperatures of a plurality of components to be cooled and a current duty cycle of a water pump specifically includes: The vehicle controller in the electric vehicle receives the temperature signal of each component to be cooled to obtain multiple actual temperatures; The water pump duty cycle signal is received by the vehicle controller in the electric vehicle to obtain the current duty cycle of the water pump.

[0018] Acquiring temperature signals and duty cycle signals through the vehicle controller can make the data more accurate and improve the reliability and timeliness of the data.

[0019] Optionally, the step of determining a target duty cycle of the water pump based on each of the actual temperatures comprises: If the vehicle controller in the electric vehicle receives a vehicle power-off signal, the target duty cycle of the water pump is 0; This step is used to control the water pump to stop rotating when the vehicle needs to be powered off.

[0020] In a second aspect, an embodiment of the present application provides a water pump control system for an electric vehicle, the system comprising: A data acquisition module, used to acquire actual temperatures of multiple components to be cooled and a water pump duty cycle; A first determination module, configured to determine a target duty cycle of the water pump based on each actual temperature; A second determination module is used to determine the duty cycle requirement of the water pump according to the target duty cycle of the water pump and the current duty cycle of the water pump; A strategy execution module, configured to execute a first control strategy to obtain an updated water pump duty cycle if the demand is increasing, and to execute a second control strategy to obtain an updated water pump duty cycle if the demand is decreasing; An output quantity calculation module, used for calculating the output quantity according to the updated water pump duty cycle; The operation control module is used to control the water pump according to the output.

[0021] In a third aspect, an embodiment of the present application provides a vehicle comprising a processor, a memory, a signal acquisition device, and a computer program or instruction stored in the memory and executable on the processor, wherein the steps of the method described in the first aspect are implemented when the computer program or instruction is executed by the processor.

[0022] In the embodiment of the present application, the temperature signals of multiple components to be cooled and the duty cycle signals of the water pump are obtained through the vehicle controller, so as to obtain the actual temperature of the components to be cooled and the current duty cycle of the water pump, which can make the data more accurate and improve the reliability and timeliness of the data; based on the actual temperature of each component to be cooled, the threshold level of the actual temperature of each component to be cooled is determined by comparing it with the preset threshold temperature, and the duty cycle required for the actual temperature of each component to be cooled is obtained according to the threshold level, and the target duty cycle of the water pump is determined based on the comparison of multiple duty cycles, which can ensure that the water pump The target duty cycle meets the cooling requirements of all components to be cooled; the duty cycle requirement of the water pump is determined to be an increasing requirement or a decreasing requirement according to the size of the current duty cycle of the water pump and the target duty cycle of the water pump; the control strategy to be executed is determined according to this requirement, if it is an increasing requirement, the first control strategy is executed, if it is a decreasing requirement, the second control strategy is executed; according to different control strategies, the increasing gradient is determined to increase the current duty cycle of the water pump or the decreasing gradient is determined to decrease the current duty cycle of the water pump to obtain the updated duty cycle of the water pump, and the duty cycle of the water pump can be adjusted and controlled in real time based on different duty cycle requirements. Therefore, this method not only considers the temperature but also the pressure to control the water pump, and can maintain the stable change of the flow rate by continuously controlling the change gradient of the water pump duty cycle, prevent the sudden increase of water pressure caused by the substantial increase or decrease of the flow rate, and damage the pipeline and other components, extend the service life of the cooling system, and does not need to install a water pressure sensor, reducing the cost of the vehicle. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 is a flow chart of a water pump control method for an electric vehicle provided by some embodiments of the present application; Figure 2 is a structural diagram of a water pump control system for an electric vehicle provided by some embodiments of the present application; Figure 3 This is a structural diagram of a vehicle provided in some embodiments of the present application. DETAILED DESCRIPTION

[0024] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of this application.

[0025] The terms "first", "second", etc. in the specification and claims of the present application are used to distinguish similar objects, and are not used to describe a specific order or sequence. It should be understood that the data used in this way can be interchangeable under appropriate circumstances, so that the embodiments of the present application can be implemented in an order other than those illustrated or described here. In addition, the "and / or" in the specification and claims represents at least one of the connected objects, and the character " / " generally represents that the objects associated with each other are in an "or" relationship.

[0026] In conjunction with the accompanying drawings, the water pump control method, system, vehicle and readable storage medium of the electric vehicle provided in the embodiments of the present application are described in detail through specific embodiments and their application scenarios.

[0027] In some embodiments of this application, please refer to Figure 1 , is a flow chart of a water pump control method for an electric vehicle proposed in a possible embodiment of the present application, wherein the proposed method includes: S101: Acquire actual temperatures of multiple components to be cooled and current duty cycle of a water pump; S102: Determine a target duty cycle of the water pump based on each actual temperature; S103: Determine the duty cycle requirement of the water pump according to the target duty cycle of the water pump and the current duty cycle of the water pump; S104: If the demand is rising, execute the first control strategy to obtain an updated water pump duty cycle and calculate the output; S105: If the demand is decreasing, execute the second control strategy to obtain an updated water pump duty cycle and calculate the output; S106: Control the water pump according to the output.

[0028] In some embodiments of the present application, S101: obtaining the actual temperature of multiple components to be cooled and the current duty cycle of the water pump. The actual temperature of multiple components to be cooled and the current duty cycle of the water pump of the pipeline are obtained through a vehicle control unit (VCU) in the electric vehicle.

[0029] In this embodiment, the actual temperature of each component to be cooled is collected by a temperature sensor installed on each component to be cooled, and the temperature signals of multiple components to be cooled are sent to the VCU to obtain the actual temperatures of multiple components to be cooled. The water pump collects relevant electrical signals through its own sensors, and after a series of processing, the collected signals are transmitted to the VCU through specific lines. These specific lines are usually cables connected to the water pump, which are responsible for transmitting the sensor signals of the water pump to the corresponding interfaces of the VCU to obtain the current duty cycle of the water pump.

[0030] It should be noted that the multiple components to be cooled include: motor, motor controller, DC-to-DC converter, on-board charger and other components.

[0031] In some embodiments of the present application, S102: Determine the target duty cycle of the water pump based on each actual temperature. For example, using a motor for illustration, the actual temperature signal of the motor input by the VCU is compared with the preset threshold temperature to obtain the threshold level of the actual temperature of the motor, and the corresponding water pump duty cycle is obtained based on the threshold temperature level. Similarly, the corresponding water pump duty cycles of other components to be cooled can be obtained, and multiple water pump duty cycles are compared to select the maximum water pump duty cycle as the target water pump duty cycle, which can meet the cooling requirements of all components to be cooled.

[0032] In this embodiment, taking the motor as an example, the threshold level corresponding to the preset threshold temperature may be: the threshold level corresponding to 70°C is the callback temperature, the threshold level corresponding to 83°C is the first threshold temperature, the threshold level corresponding to 92°C is the second threshold temperature, the threshold level corresponding to 100°C is the third threshold temperature, and the threshold level corresponding to 110°C is the fourth threshold temperature. Among them, the required water pump duty cycle corresponding to the callback temperature may be 20%, the required water pump duty cycle corresponding to the first threshold temperature may be 35%, the required water pump duty cycle corresponding to the second threshold temperature may be 45%, the required water pump duty cycle corresponding to the third threshold temperature may be 65%, and the required water pump duty cycle corresponding to the fourth threshold temperature may be 85%.

[0033] It is worth noting that if the actual temperature of the motor is lower than the callback temperature of 70°C, the water pump duty cycle will not be turned on, and the water pump duty cycle is 0 at this time. Generally, if the motor temperature is between 70°C and 83°C, the corresponding water pump duty cycle can be 20% to 35%; if the motor temperature is between 83°C and 92°C, the corresponding water pump duty cycle can be 35% to 45%; if the motor temperature is between 92°C and 100°C, the corresponding water pump duty cycle can be 45% to 65%; if the motor temperature is between 100°C and 110°C, the corresponding water pump duty cycle can be 65% to 85%. The existing linear interpolation method is used to obtain the value, and the water pump duty cycle corresponding to the actual temperature of other components to be cooled can be obtained in the same way.

[0034] It should be noted that the preset threshold temperature is set based on the cooling requirements of different components to be cooled, and the water pump duty cycle corresponding to the threshold level is obtained based on the heat dissipation requirements of different components to be cooled. The required heat dissipation is calculated according to the temperature of different components to be cooled, and then the required water flow through the pipeline is obtained, and finally the required water pump duty cycle is obtained. Different components to be cooled have different preset threshold temperatures and threshold levels corresponding to different water pump duty cycles, which need to be obtained based on actual conditions.

[0035] In some embodiments of the present application, if the VCU in the electric vehicle receives a power-off signal of the vehicle, the acquired water pump target duty cycle is 0, and the water pump is controlled to gradually stop running.

[0036] In some embodiments of the present application, S103: Determine the duty cycle requirement of the water pump according to the target duty cycle of the water pump and the current duty cycle of the water pump. The target duty cycle of the water pump is compared with the current duty cycle of the water pump to determine the duty cycle requirement of the water pump.

[0037] In this embodiment, if the current duty cycle of the water pump obtained by the VCU is less than the target duty cycle of the water pump, the duty cycle demand of the water pump is an increasing demand; if the current duty cycle of the water pump obtained by the VCU is greater than the target duty cycle of the water pump, the duty cycle demand of the water pump is a decreasing demand. The corresponding control strategy is executed according to the increasing demand or decreasing demand to control the change of the water pump duty cycle until the target duty cycle is reached.

[0038] In some embodiments of the present application, S104: if it is an increasing demand, execute the first control strategy to obtain an updated water pump duty cycle and calculate the output.

[0039] In this embodiment, the first control strategy includes: Step S201, defining the threshold range of the water pump duty cycle x and the increase adjustment amount y of the current water pump duty cycle, where 0%≤x≤90%; Step S202, dividing the threshold range into a first threshold range a1, a second threshold range b1, a third threshold range c1 and a fourth threshold range d1 in ascending order, which correspond to the first gradient value, the second gradient value, the third gradient value and the fourth gradient value of the rising adjustment amount y of the current duty cycle of the water pump respectively; Step S203, determining a threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S204, determining the gradient value of the rising adjustment amount y according to the threshold range; Step S205, adjusting the current duty cycle of the water pump upward according to the gradient value to obtain an updated duty cycle of the water pump; Step S206, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; Step S207: if not, the updated water pump duty cycle is used as the current water pump duty cycle, and steps S203 to S206 are repeated; Step S208: If yes, output the updated water pump duty cycle.

[0040] In this embodiment, the threshold range is divided into different sub-ranges (a first threshold range a1, a second threshold range b1, a third threshold range c1 and a fourth threshold range d1), and a corresponding gradient value of the rising adjustment amount y is assigned to each sub-range. By subdividing the duty cycle range, the adjustment amount of the duty cycle can be more finely controlled to achieve a smoother adjustment effect. Different sub-ranges correspond to different adjustment gradients, which can be adjusted according to actual conditions to achieve better control effects. The gradient value of the rising adjustment amount y determined according to the threshold range can be selected based on the sub-range where the current duty cycle is located, ensuring that the adjustment amount is neither too large nor too small, and maintaining the stability and response speed of the system. After the current duty cycle of the water pump is increased according to the gradient value, the updated duty cycle of the water pump is obtained. The current duty cycle can be increased according to the determined adjustment gradient value to obtain a new duty cycle value to achieve a step-by-step adjustment of the duty cycle.

[0041] In some embodiments of the present application, in step S202 of the first strategy: The first threshold range a1 is: 0≤a1<20%, ​​and the corresponding first gradient value is: 10; The second threshold range b1 is: 20%≤b1<40%, and the corresponding second gradient value is: 2; The third threshold range c1 is: 40%≤c1<70%, and the corresponding third gradient value is: 5; The fourth threshold range d1 is: 70%≤d1≤90%, and the corresponding fourth gradient value is: 10.

[0042] Refer to the schematic table 1 as follows, the horizontal axis (X axis) is the water pump duty cycle, and the vertical axis (Y axis) is the water pump duty cycle rising gradient value: Table 1 Correspondence between water pump duty cycle and water pump duty cycle rising gradient value In this embodiment, when the duty cycle of the water pump is small, that is, when the flow rate of the water flow is low, no large water pressure will be generated, and this process can be passed quickly. If the current duty cycle of the water pump is increased from 0% to 20%, this process can give a faster rising gradient. During the duty cycle increase process of the water pump, that is, when the water flow rate is higher than a certain level, the water circuit pressure rises rapidly in this process. In this process, if a high water pump rising gradient is maintained, it will cause excessive water pressure, and then produce a "water hammer effect"; based on this, when the duty cycle of the water pump rises to 20%, the duty cycle rising gradient of the water pump needs to be reduced to ensure a steady increase in the water flow rate. When the water pump flow rate is stable, that is, when the duty cycle of the water pump reaches about 40%, the water pressure is in a stable state. In order to reduce the time required for water pump control, it is necessary to increase the downward gradient of the water pump at a high duty cycle.

[0043] In some embodiments of the present application, S105: if it is a decreasing demand, execute the second control strategy to obtain an updated water pump duty cycle and calculate the output.

[0044] In this embodiment, the second control strategy includes: Step S301, defining the threshold range of the water pump duty cycle x1 and the downward adjustment amount y1 of the current water pump duty cycle, where 90% ≥ x1 ≥ 0%; Step S302, dividing the threshold range into a fifth threshold range a2, a sixth threshold range b2, a seventh threshold range c2 and an eighth threshold range d2 in descending order, which respectively correspond to the fifth gradient value, the sixth gradient value, the seventh gradient value and the eighth gradient value of the downward adjustment amount y1 of the current duty cycle of the water pump; Step S303, determining a threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S304, determining the gradient value of the downward adjustment amount y1 according to the threshold range; Step S305, adjusting the current duty cycle of the water pump downward according to the gradient value to obtain an updated duty cycle of the water pump; Step S306, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; Step S307: if not, the updated water pump duty cycle is used as the current water pump duty cycle, and steps S303 to S306 are repeated; Step S308: If yes, output the updated water pump duty cycle.

[0045] In this embodiment, the threshold range is divided into different sub-ranges (fifth threshold range a2, sixth threshold range b2, seventh threshold range c2 and eighth threshold range d2), and the corresponding gradient value of the downward adjustment amount y1 is assigned to each sub-range. By subdividing the duty cycle range, the adjustment amount of the duty cycle can be more finely controlled to achieve a smoother adjustment effect. Different sub-ranges correspond to different adjustment gradients, which can be adjusted according to actual conditions to achieve better control effects. Determining the gradient value of the downward adjustment amount y1 according to the threshold range in which it is located can select the corresponding adjustment gradient value based on the sub-range in which the current duty cycle is located, ensuring that the adjustment amount is neither too large nor too small, and maintaining the stability and response speed of the system. After the current duty cycle of the water pump is lowered according to the gradient value, the updated duty cycle of the water pump is obtained. The current duty cycle can be lowered according to the determined adjustment gradient value to obtain a new duty cycle value to achieve a step-by-step adjustment of the duty cycle.

[0046] In some embodiments of the present application, in step S202 of the first strategy: The fifth threshold range a2 is: 90%≥a2>60%, and the corresponding fifth gradient value is: 10; The sixth threshold range b2 is: 60% ≥ b2 > 40%, and the corresponding sixth gradient value is: 5; The seventh threshold range c2 is: 40% ≥ c2 > 10%, and the corresponding seventh gradient value is: 2; The eighth threshold range d2 is: 10%≥d2≥0%, and the corresponding eighth gradient value is: 5.

[0047] Refer to the schematic table 2 as follows, the horizontal axis (X axis) is the water pump duty cycle, and the vertical axis (Y axis) is the water pump duty cycle decrease gradient value: Table 2 Correspondence between water pump duty cycle and water pump duty cycle decrease gradient value In this embodiment, if the water pump is already running at a high duty cycle, such as 90%, the flow rate of the water flow has tended to be stable. At this time, a small adjustment of the duty cycle of the water pump will not generate a large water pressure, and this process can be adjusted quickly. During the process of the water pump's duty cycle decreasing, that is, when the water flow rate is lower than a certain level, the water circuit pressure rises rapidly during this process. During this process, if a high water pump descent gradient is maintained, it will cause excessive water pressure, and then produce a "water hammer effect"; based on this, when the water pump duty cycle drops to 40%, the water pump duty cycle descent gradient needs to be reduced to ensure a steady decline in the water flow rate. When the water pump flow rate is stable, that is, when the water pump duty cycle reaches about 10%, the water pressure is in a stable state. In order to reduce the time required for water pump control, it is necessary to appropriately increase the descent gradient of the water pump at a low duty cycle.

[0048] In some embodiments of the present application, S106: control the water pump according to the output; the output may be flow rate, rotation speed, etc. The output is applied to the controller of the water pump to adjust the operating state of the water pump to achieve the effect of smoothly controlling the flow rate.

[0049] In summary, the method obtains temperature signals and water pump duty cycle signals of multiple components to be cooled through the vehicle controller, thereby obtaining the actual temperature of the components to be cooled and the current duty cycle of the water pump, which can make the data more accurate and improve the reliability and timeliness of the data; based on the actual temperature of each component to be cooled, by comparing it with the preset threshold temperature, the threshold level of the actual temperature of each component to be cooled is determined, and the duty cycle required for the actual temperature of each component to be cooled is obtained according to the threshold level, and the target duty cycle of the water pump is determined based on the comparison of multiple duty cycles, which can ensure the target duty cycle of the water pump The standard duty cycle meets the cooling requirements of all components to be cooled; the duty cycle requirement of the water pump is determined to be an increasing requirement or a decreasing requirement according to the size of the current duty cycle of the water pump and the target duty cycle of the water pump; the control strategy to be executed is determined according to this requirement, if it is an increasing requirement, the first control strategy is executed, if it is a decreasing requirement, the second control strategy is executed; according to different control strategies, the increasing gradient is determined to increase the current duty cycle of the water pump or the decreasing gradient is determined to decrease the current duty cycle of the water pump to obtain the updated duty cycle of the water pump, and the duty cycle of the water pump can be adjusted and controlled in real time based on different duty cycle requirements. Therefore, this method not only considers the temperature but also the pressure to control the water pump, and can maintain the stable change of the flow rate by continuously controlling the change gradient of the water pump duty cycle, prevent the sudden increase of water pressure caused by the substantial increase or decrease of the flow rate, and damage the pipeline and other components, extend the service life of the cooling system, and does not need to install a water pressure sensor, reducing the cost of the vehicle.

[0050] In some embodiments of this application, please refer to Figure 2 , is a structural diagram of a water pump control system of an electric vehicle, the water pump control system 200 of the electric vehicle comprises: A data acquisition module 210 is used to acquire actual temperatures of multiple components to be cooled and a water pump duty cycle; A first determination module 220, configured to determine a target duty cycle of the water pump based on each actual temperature; A second determination module 230, configured to determine a water pump duty cycle requirement according to a water pump target duty cycle and a water pump current duty cycle; A strategy execution module 240 is used to execute the first control strategy to obtain an updated water pump duty cycle if the demand is increasing, and to execute the second control strategy to obtain an updated water pump duty cycle if the demand is decreasing; An output calculation module 250, configured to calculate the output according to the updated water pump duty cycle; The operation control module 260 is used to control the water pump according to the output.

[0051] Optionally, the present application embodiment further provides a vehicle 300, see Figure 3 , is a structural diagram of a vehicle 300, including a signal acquisition device 310, a processor 320, a memory 330, and a computer program 340 or instruction stored in the memory and executable on the processor. When the computer program 340 or instruction is executed by the processor, each process of the water pump control method embodiment of the above-mentioned electric vehicle is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0052] The processor is a processor in the electronic device described in the above embodiment. The memory is a readable storage medium, including a computer readable storage medium, such as a computer read-only memory (ROM), a random access memory (RAM), a magnetic disk or an optical disk, etc. The memory can be an external storage device of the vehicle, such as a plug-in hard disk or a smart memory card equipped on the vehicle; it can also be an internal storage unit of the vehicle; the memory can be used not only to store application software installed in the vehicle and various types of data, but also to temporarily store data that has been output or is to be output.

[0053] An embodiment of the present application further provides a chip, which includes a processor and a communication interface, wherein the communication interface is coupled to the processor, and the processor is used to run programs or instructions to implement the various processes of the above-mentioned electric vehicle water pump control method embodiment, and can achieve the same technical effect. To avoid repetition, it will not be repeated here.

[0054] It should be understood that the chip mentioned in the embodiments of the present application can also be called a system-level chip, a system chip, a chip system or a system-on-chip chip, etc.

[0055] It should be noted that, in this article, the terms "comprise", "include" or any other variant thereof are intended to cover non-exclusive inclusion, so that the process, method, article or device including a series of elements includes not only those elements, but also includes other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise one..." do not exclude the presence of other identical elements in the process, method, article or device including the element. In addition, it should be pointed out that the scope of the methods and devices in the embodiments of the present application is not limited to performing functions in the order shown or discussed, and may also include performing functions in a substantially simultaneous manner or in reverse order according to the functions involved, for example, the described method may be performed in an order different from that described, and various steps may also be added, omitted, or combined. In addition, the features described with reference to certain examples may be combined in other examples.

[0056] Through the description of the above implementation methods, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus a necessary general hardware platform, and of course by hardware, but in many cases the former is a better implementation method. Based on such an understanding, the technical solution of the present application, or the part that contributes to the prior art, can be embodied in the form of a software product, which is stored in a storage medium (such as ROM / RAM, a magnetic disk, or an optical disk), and includes a number of instructions for a terminal (which can be a mobile phone, a computer, a server, an air conditioner, or a network device, etc.) to execute the methods described in each embodiment of the present application.

[0057] The embodiments of the present application are described above in conjunction with the accompanying drawings, but the present application is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present application, ordinary technicians in this field can also make many forms without departing from the purpose of the present application and the scope of protection of the claims, all of which are within the protection of the present application.

Claims

1. A water pump control method for an electric vehicle, applied to a thermal management system, wherein the thermal management system comprises a water pipeline, a water pump and a plurality of components to be cooled, characterized in that: The method comprises: Obtain the actual temperature of multiple components to be cooled and the current duty cycle of the water pump; determining a target duty cycle of the water pump based on each of the actual temperatures; Determining a water pump duty cycle requirement according to the water pump target duty cycle and the water pump current duty cycle; If it is an increasing demand, the first control strategy is executed to obtain the updated duty cycle of the water pump and calculate the output; If it is a decreasing demand, the second control strategy is executed to obtain the updated duty cycle of the water pump and calculate the output; The water pump is controlled according to the output.

2. The water pump control method of an electric vehicle according to claim 1, characterized in that: The first control strategy includes: Step S201, defining a threshold range of a water pump duty cycle x and an increase adjustment amount y of the current water pump duty cycle, wherein 0%≤x≤90%; Step S202, dividing the threshold range into a first threshold range a1, a second threshold range b1, a third threshold range c1 and a fourth threshold range d1 in ascending order, which correspond to the first gradient value, the second gradient value, the third gradient value and the fourth gradient value of the rising adjustment amount y of the current duty cycle of the water pump respectively; Step S203, determining a threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S204, determining the gradient value of the rising adjustment amount y according to the threshold range; Step S205, increasing the current duty cycle of the water pump according to the gradient value to obtain an updated duty cycle of the water pump; Step S206, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; Step S207: if not, taking the updated water pump duty cycle as the current water pump duty cycle, and repeating steps S203 to S206; Step S208: If yes, output the updated water pump duty cycle.

3. The water pump control method of an electric vehicle according to claim 2, characterized in that: In step S202, The first threshold range a1 is: 0≤a1<20%, ​​and the corresponding first gradient value is: 10; The second threshold range b1 is: 20%≤b1<40%, and the corresponding second gradient value is: 2; The third threshold range c1 is: 40%≤c1<70%, and the corresponding third gradient value is: 5; The fourth threshold range d1 is: 70%≤d1≤90%, and the corresponding fourth gradient value is:

10.

4. The water pump control method of an electric vehicle according to claim 1, characterized in that: The second control strategy includes: Step S301, defining a threshold range of the water pump duty cycle x1 and a decreasing adjustment amount y1 of the current water pump duty cycle, wherein 90% ≥ x1 ≥ 0%; Step S302, dividing the threshold range into a fifth threshold range a2, a sixth threshold range b2, a seventh threshold range c2 and an eighth threshold range d2 in descending order, which respectively correspond to the fifth gradient value, the sixth gradient value, the seventh gradient value and the eighth gradient value of the downward adjustment amount y1 of the current duty cycle of the water pump; Step S303, determining a threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S304, determining the gradient value of the downward adjustment amount y1 according to the threshold range; Step S305, adjusting the current duty cycle of the water pump downward according to the gradient value to obtain an updated duty cycle of the water pump; Step S306, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; Step S307: if not, taking the updated water pump duty cycle as the current water pump duty cycle, and repeating steps S303 to S306; Step S308: If yes, output the updated water pump duty cycle.

5. The water pump control method of an electric vehicle according to claim 4, characterized in that: In step S302, The fifth threshold range a2 is: 90%≥a2>60%, and the corresponding fifth gradient value is: 10; The sixth threshold range b2 is: 60% ≥ b2 > 40%, and the corresponding sixth gradient value is: 5; The seventh threshold range c2 is: 40% ≥ c2 > 10%, and the corresponding seventh gradient value is: 2; The eighth threshold range d2 is: 10%≥d2≥0%, and the corresponding eighth gradient value is:

5.

6. The water pump control method of an electric vehicle according to claim 1, characterized in that: The step of determining the target duty cycle of the water pump based on each of the actual temperatures specifically includes: Determining a threshold temperature level of the component to be cooled by presetting a threshold temperature of the component to be cooled; determining a water pump duty cycle based on the threshold temperature level; Comparing the actual temperature of each of the components to be cooled with a preset threshold temperature to obtain a preset threshold temperature level corresponding to each of the actual temperatures; Acquire a one-to-one corresponding water pump duty cycle based on the obtained multiple preset threshold temperature levels; The plurality of water pump duty cycles are compared, and the maximum water pump duty cycle is selected as the water pump target duty cycle.

7. The water pump control method of an electric vehicle according to claim 1, characterized in that: The step of obtaining the actual temperatures of the multiple components to be cooled and the current duty cycle of the water pump specifically includes: Receiving the temperature signal of each component to be cooled by a vehicle controller in the electric vehicle to obtain the multiple actual temperatures; The water pump duty cycle signal is received by a vehicle controller in the electric vehicle to obtain the current duty cycle of the water pump.

8. The water pump control method of an electric vehicle according to claim 1, characterized in that: The step of determining the target duty cycle of the water pump based on each of the actual temperatures comprises: If the vehicle controller in the electric vehicle receives a vehicle power-off signal, the target duty cycle of the water pump is 0.

9. A water pump control system for an electric vehicle, characterized in that: The system comprises: A data acquisition module, used to acquire actual temperatures of multiple components to be cooled and a water pump duty cycle; A first determination module, configured to determine a target duty cycle of the water pump based on each of the actual temperatures; A second determination module, configured to determine a water pump duty cycle increase or decrease requirement according to the water pump target duty cycle and the water pump current duty cycle; A strategy execution module, configured to execute a first control strategy to obtain an updated water pump duty cycle if the demand is increasing, and to execute a second control strategy to obtain an updated water pump duty cycle if the demand is decreasing; An output quantity calculation module, used for calculating the output quantity according to the updated water pump duty cycle; The operation control module is used to control the water pump according to the output.

10. A vehicle, characterized in that: It includes a processor, a memory, and a program or instruction stored in the memory and executable on the processor. When the program or instruction is executed by the processor, the steps of the water pump control method of the electric vehicle as described in claims 1-8 are implemented.

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