Water pump control method, system and vehicle for electric vehicle

Abstract

The present application discloses a water pump control method, system, and vehicle for an electric vehicle, belonging to the field of electric vehicle thermal management. The method comprises: obtaining the actual temperatures of multiple components to be cooled and the current duty cycle of the water pump; determining the target duty cycle of the water pump based on each actual temperature; determining the water pump duty cycle increase or decrease demand based on the target duty cycle and the current duty cycle of the water pump; if the demand is an increase, executing a first control strategy to obtain an updated water pump duty cycle and calculate the output; if the demand is a decrease, executing a second control strategy to obtain an updated water pump duty cycle and calculate the output; and controlling the water pump based on the output. This method can maintain a stable change in the water pump duty cycle, solve the problem of sudden increase in water pressure due to a significant increase or decrease in water flow, which damages components such as pipelines, and extend the service life of the cooling system. It also does not require the installation of a water pressure sensor, reducing vehicle costs.

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 electric vehicles. Background Art

[0002] Electric vehicles all have thermal management systems, one of the core components of which is the water pump. When the water pump is turned on, it causes a sudden and significant increase in cooling flow, which in turn causes a sudden increase in water pressure, impacting pipe walls, the water pump, valves, and other components in the water path. This sudden increase in water pressure is caused by the inertia of water or other coolants, a phenomenon known as the "water hammer effect." Similarly, when the water pump is turned off, it causes a sudden and significant decrease in cooling flow, resulting in 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 channel. When the power is on, the vehicle controller sets the corresponding duty cycle according to the temperature of each component in the water channel, 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:

[0005] (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 working conditions. Excessive water pressure will reduce the durability of components such as water pipes and water pumps, and may also cause damage to the pipelines;

[0006] (2) If additional pressure measurement is required inside the water channel, the vehicle needs to install a pressure sensor in the water channel pipeline, which increases the cost of the vehicle. Summary of the Invention

[0007] 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 damaging pipelines and other components due to the opening or closing of the water pump or a significant 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 vehicle costs.

[0008] In order to solve the above technical problems, this application is implemented as follows:

[0009] 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. The thermal management system includes a water pipe, a water pump, and multiple components to be cooled. The method includes:

[0010] Obtain the actual temperature of multiple components to be cooled and the current duty cycle of the water pump;

[0011] determining a target duty cycle of the water pump based on each actual temperature;

[0012] Determine the duty cycle requirement of the water pump based on the target duty cycle of the water pump and the current duty cycle of the water pump;

[0013] If the demand is rising, the first control strategy is executed to obtain the updated pump duty cycle and calculate the output;

[0014] If the demand is decreasing, the second control strategy is executed to obtain the updated pump duty cycle and calculate the output;

[0015] The water pump is controlled according to the output.

[0016] Optionally, if the demand is rising, executing the first control strategy to obtain the updated water pump duty cycle and calculating the output comprises:

[0017] Step S201 , defining the threshold range of the water pump duty cycle x and the increase adjustment amount y of the water pump current duty cycle, where 0%≤x≤90%;

[0018] 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;

[0019] 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;

[0020] Step S204, determining the gradient value of the rising adjustment amount y according to the threshold range;

[0021] 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;

[0022] Step S206, determining whether the updated water pump duty cycle reaches the water pump target duty cycle;

[0023] 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;

[0024] Step S208: If yes, output the updated water pump duty cycle.

[0025] By subdividing the duty cycle range, the duty cycle increase adjustment amount can be controlled more finely, achieving a smoother increase adjustment effect.

[0026] Optionally, in step S202 of the first strategy:

[0027] The first threshold range a1 is: 0≤a1<20%, ​​and the corresponding first gradient value is: 10;

[0028] The second threshold range b1 is: 20%≤b1<40%, and the corresponding second gradient value is: 2;

[0029] The third threshold range c1 is: 40%≤c1<70%, and the corresponding third gradient value is: 5;

[0030] The fourth threshold range d1 is: 70%≤d1≤90%, and the corresponding fourth gradient value is: 10.

[0031] Different sub-ranges correspond to different adjustment rising gradients, which can be adjusted according to actual conditions to achieve better control effects.

[0032] 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:

[0033] Step S301 , defining the threshold range of the water pump duty cycle x1 and the decrease adjustment amount y1 of the water pump current duty cycle, where 90% ≥ x1 ≥ 0%;

[0034] 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 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, respectively;

[0035] 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;

[0036] Step S304, determining the gradient value of the downward adjustment amount y1 according to the threshold range;

[0037] Step S305, the current duty cycle of the water pump is adjusted downward according to the gradient value to obtain an updated duty cycle of the water pump;

[0038] Step S306, determining whether the updated water pump duty cycle reaches the water pump target duty cycle;

[0039] 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;

[0040] Step S308: If yes, output the updated water pump duty cycle.

[0041] By subdividing the duty cycle range, the duty cycle down-regulation amount can be controlled more finely, achieving a smoother down-regulation effect.

[0042] Optionally, in step S302 of the second strategy:

[0043] The fifth threshold range a2 is: 90% ≥ a2 > 60%, and the corresponding fifth gradient value is: 10;

[0044] The sixth threshold range b2 is: 60% ≥ b2 > 40%, and the corresponding sixth gradient value is: 5;

[0045] The seventh threshold range c2 is: 40% ≥ c2 > 10%, and the corresponding seventh gradient value is: 2;

[0046] The eighth threshold range d2 is: 10%≥d2≥0%, and the corresponding eighth gradient value is: 5.

[0047] Different sub-ranges correspond to different adjustment descent gradients, which can be adjusted according to actual conditions to achieve better control effects.

[0048] Optionally, the step of determining a target duty cycle of the water pump based on each actual temperature specifically includes:

[0049] Determining a threshold temperature level of the component to be cooled by presetting a threshold temperature of the component to be cooled;

[0050] Determine the water pump duty cycle based on the threshold temperature level;

[0051] Comparing the actual temperature of each component to be cooled with a preset threshold temperature to obtain the preset threshold temperature level corresponding to each actual temperature;

[0052] Obtaining a one-to-one corresponding water pump duty cycle based on the obtained multiple preset threshold temperature levels;

[0053] The duty cycles of multiple water pumps are compared, and the maximum water pump duty cycle is selected as the target water pump duty cycle.

[0054] By screening out the maximum 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.

[0055] 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:

[0056] The vehicle controller in the electric vehicle receives a temperature signal of each component to be cooled to obtain multiple actual temperatures;

[0057] 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.

[0058] Obtaining 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.

[0059] Optionally, the step of determining a target duty cycle of the water pump based on each actual temperature includes:

[0060] If the vehicle controller in the electric vehicle receives a vehicle power-off signal, the target duty cycle of the water pump is 0;

[0061] This step is used to control the water pump to stop rotating when the vehicle needs to be powered off.

[0062] In a second aspect, an embodiment of the present application provides a water pump control system for an electric vehicle, the system comprising:

[0063] A data acquisition module, used to obtain actual temperatures of multiple components to be cooled and a water pump duty cycle;

[0064] a first determining module, configured to determine a target duty cycle of the water pump based on each actual temperature;

[0065] A second determining 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;

[0066] 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;

[0067] an output calculation module, configured to calculate the output according to the updated water pump duty cycle;

[0068] The operation control module is used to control the water pump according to the output.

[0069] 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.

[0070] In the embodiment of the present application, the temperature signals and water pump duty cycle signals of multiple components to be cooled are obtained 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, 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. 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 needs of all components to be cooled; the water pump duty cycle demand is determined to be an increasing demand or a decreasing demand based on the size of the water pump's current duty cycle and the water pump's target duty cycle; the control strategy to be executed is determined based on this demand; if it is an increasing demand, the first control strategy is executed; if it is a decreasing demand, the second control strategy is executed; based on different control strategies, an increasing gradient is determined to increase the water pump's current duty cycle, or a decreasing gradient is determined to decrease the water pump's current duty cycle to obtain an updated water pump duty cycle, and the water pump duty cycle can be adjusted and controlled in real time based on different duty cycle demands. Therefore, this method controls the water pump not only by considering temperature but also by considering pressure. It can maintain a stable flow rate by continuously controlling the gradient of the water pump duty cycle change, preventing a sudden increase in water pressure caused by a large increase or decrease in flow rate, which can damage components such as pipes, thereby extending the service life of the cooling system. It also does not require the installation of a water pressure sensor, reducing vehicle costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0071] Figure 1 is a flow chart of a water pump control method for an electric vehicle provided by some embodiments of the present application;

[0072] Figure 2 is a structural diagram of a water pump control system for an electric vehicle provided by some embodiments of the present application;

[0073] Figure 3 This is a structural diagram of a vehicle provided in some embodiments of the present application. DETAILED DESCRIPTION

[0074] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are part of the embodiments of this application, not all of them. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0075] The terms "first," "second," and the like in the specification and claims of this application are used to distinguish similar objects and are not used to describe a particular order or precedence. It should be understood that the terms used in this manner are interchangeable where appropriate so that the embodiments of this application can be implemented in an order other than those illustrated or described herein. In addition, the term "and / or" in the specification and claims refers to at least one of the connected objects, and the character " / " generally indicates that the objects associated with each other are in an "or" relationship.

[0076] The water pump control method, system, vehicle and readable storage medium of the electric vehicle provided by the embodiments of the present application are described in detail below with reference to the accompanying drawings through specific embodiments and their application scenarios.

[0077] In some embodiments of this application, please refer to Figure 1 , which 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:

[0078] S101: Acquire the actual temperatures of multiple components to be cooled and the current duty cycle of the water pump;

[0079] S102: Determine a target duty cycle of the water pump based on each actual temperature;

[0080] S103: Determine the water pump duty cycle requirement based on the water pump target duty cycle and the water pump current duty cycle;

[0081] S104: If the demand is rising, execute the first control strategy to obtain the updated water pump duty cycle and calculate the output;

[0082] S105: If the demand is decreasing, execute the second control strategy to obtain the updated water pump duty cycle and calculate the output;

[0083] S106: Control the water pump according to the output.

[0084] In some embodiments of the present application, S101: obtaining actual temperatures of multiple components to be cooled and current duty cycles of water pumps. The actual temperatures of multiple components to be cooled in the pipeline and the current duty cycles of the water pumps are obtained via a vehicle control unit (VCU) in the electric vehicle.

[0085] 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.

[0086] 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.

[0087] In some embodiments of the present application, S102: Determine a target water pump duty cycle based on each actual temperature. For example, using a motor as an example, the actual motor temperature signal input by the VCU is compared with a preset threshold temperature to obtain the threshold level of the motor's actual temperature. Based on the threshold temperature level, the corresponding water pump duty cycle is obtained. Similarly, the corresponding water pump duty cycles of other components to be cooled can be obtained. Multiple water pump duty cycles are compared, and the maximum water pump duty cycle is selected as the target water pump duty cycle. This target water pump duty cycle can meet the cooling requirements of all components to be cooled.

[0088] In this embodiment, taking a motor as an example, the threshold levels corresponding to the preset threshold temperatures may be: 70°C for the reset temperature, 83°C for the first threshold temperature, 92°C for the second threshold temperature, 100°C for the third threshold temperature, and 110°C for the fourth threshold temperature. The required water pump duty cycle for the reset temperature may be 20%, the required water pump duty cycle for the first threshold temperature may be 35%, the required water pump duty cycle for the second threshold temperature may be 45%, the required water pump duty cycle for the third threshold temperature may be 65%, and the required water pump duty cycle for the fourth threshold temperature may be 85%.

[0089] It is worth noting that if the actual motor temperature is lower than the callback temperature of 70°C, the water pump duty cycle will not be turned on. At this time, the water pump duty cycle is 0. 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. Similarly, the water pump duty cycle corresponding to the actual temperature of other components to be cooled can be obtained.

[0090] It should be noted that the preset threshold temperature is set based on the cooling requirements of different components to be cooled. The corresponding water pump duty cycle for each threshold level is determined based on the heat dissipation requirements of different components to be cooled. The required heat dissipation is calculated based on the temperature of each component to be cooled, which in turn determines the required water flow through the pipeline and the required water pump duty cycle. The preset threshold temperature and threshold level for each component to be cooled will vary, and the specific pump duty cycle will be determined based on actual conditions.

[0091] In some embodiments of the present application, if the VCU in the electric vehicle receives a power-off signal of the vehicle, the acquired target duty cycle of the water pump is 0, and the water pump is controlled to gradually stop running.

[0092] In some embodiments of the present application, S103: determining a water pump duty cycle requirement according to the water pump target duty cycle and the water pump current duty cycle. The water pump target duty cycle is compared with the water pump current duty cycle to determine the water pump duty cycle requirement.

[0093] 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 water pump duty cycle demand 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 water pump duty cycle demand 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.

[0094] 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.

[0095] In this embodiment, the first control strategy includes:

[0096] Step S201 , defining the threshold range of the water pump duty cycle x and the increase adjustment amount y of the water pump current duty cycle, where 0%≤x≤90%;

[0097] 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;

[0098] 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;

[0099] Step S204, determining the gradient value of the rising adjustment amount y according to the threshold range;

[0100] 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;

[0101] Step S206, determining whether the updated water pump duty cycle reaches the water pump target duty cycle;

[0102] 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;

[0103] Step S208: If yes, output the updated water pump duty cycle.

[0104] In this embodiment, the threshold range is divided into different subranges (a1, b1, c1, and d1), and each subrange is assigned a corresponding gradient value for the rising adjustment variable y. By subdividing the duty cycle range, the duty cycle adjustment variable can be more precisely controlled, achieving a smoother adjustment effect. Different subranges correspond to different adjustment gradients, which can be adjusted according to actual conditions to achieve better control. By determining the gradient value of the rising adjustment variable y based on the threshold range, the corresponding adjustment gradient value can be selected based on the subrange in which the current duty cycle falls, ensuring that the adjustment variable is neither too large nor too small, maintaining system stability and responsiveness. The current pump duty cycle is adjusted upward by the gradient value to obtain an updated pump duty cycle. Based on the determined adjustment gradient value, the current duty cycle can be adjusted upward to obtain a new duty cycle value, achieving gradual duty cycle adjustment.

[0105] In some embodiments of the present application, in step S202 of the first strategy:

[0106] The first threshold range a1 is: 0≤a1<20%, ​​and the corresponding first gradient value is: 10;

[0107] The second threshold range b1 is: 20%≤b1<40%, and the corresponding second gradient value is: 2;

[0108] The third threshold range c1 is: 40%≤c1<70%, and the corresponding third gradient value is: 5;

[0109] The fourth threshold range d1 is: 70%≤d1≤90%, and the corresponding fourth gradient value is: 10.

[0110] Refer to the schematic table 1 below, 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:

[0111] Table 1 Correspondence between water pump duty cycle and water pump duty cycle rising gradient value

[0112]

[0113] In this embodiment, when the duty cycle of the water pump is small, that is, when the water flow rate is low, no large water pressure will be generated, and this process can be completed quickly. If the current duty cycle of the water pump is increased from 0% to 20%, this process can provide a faster rising gradient. During the process of the water pump's duty cycle rising, that is, when the water flow rate is higher than a certain level, the water circuit pressure rises rapidly in this process. During 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 water pump's duty cycle rises to 20%, the water pump's duty cycle rising gradient needs to be reduced to ensure a steady increase in the water flow rate. When the water pump's flow rate stabilizes, that is, when the water pump's duty cycle 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 water pump's descending gradient at high duty cycles.

[0114] 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.

[0115] In this embodiment, the second control strategy includes:

[0116] Step S301 , defining the threshold range of the water pump duty cycle x1 and the decrease adjustment amount y1 of the water pump current duty cycle, where 90% ≥ x1 ≥ 0%;

[0117] 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 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, respectively;

[0118] 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;

[0119] Step S304, determining the gradient value of the downward adjustment amount y1 according to the threshold range;

[0120] Step S305, the current duty cycle of the water pump is adjusted downward according to the gradient value to obtain an updated duty cycle of the water pump;

[0121] Step S306, determining whether the updated water pump duty cycle reaches the water pump target duty cycle;

[0122] 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;

[0123] Step S308: If yes, output the updated water pump duty cycle.

[0124] 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 each sub-range is assigned a corresponding gradient value for the downward adjustment amount y1. By subdividing the duty cycle range, the duty cycle adjustment amount can be more precisely controlled, achieving 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. By determining the gradient value for the downward adjustment amount y1 based on the threshold range, the corresponding adjustment gradient value can be selected based on the sub-range in which the current duty cycle falls, ensuring that the adjustment amount is neither too large nor too small, maintaining system stability and responsiveness. The current pump duty cycle is adjusted downward by the gradient value to obtain an updated pump duty cycle. Based on the determined adjustment gradient value, the current duty cycle can be adjusted downward to obtain a new duty cycle value, achieving gradual duty cycle adjustment.

[0125] In some embodiments of the present application, in step S202 of the first strategy:

[0126] The fifth threshold range a2 is: 90% ≥ a2 > 60%, and the corresponding fifth gradient value is: 10;

[0127] The sixth threshold range b2 is: 60% ≥ b2 > 40%, and the corresponding sixth gradient value is: 5;

[0128] The seventh threshold range c2 is: 40% ≥ c2 > 10%, and the corresponding seventh gradient value is: 2;

[0129] The eighth threshold range d2 is: 10%≥d2≥0%, and the corresponding eighth gradient value is: 5.

[0130] Refer to Table 2 below, where 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:

[0131] Table 2 Correspondence between water pump duty cycle and water pump duty cycle decrease gradient value

[0132]

[0133] In this embodiment, if the water pump is already operating at a high duty cycle, such as 90%, the water flow rate has stabilized. At this time, a small adjustment to the water pump duty cycle 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, 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 descent of the water flow rate. When the water pump flow rate stabilizes, that is, when the water pump duty cycle reaches approximately 10%, the water pressure is in a stable state. In order to reduce the time required for water pump control, the water pump's descent gradient at low duty cycles needs to be appropriately increased.

[0134] In some embodiments of the present application, S106: control the water pump according to the output; the output can be flow rate, speed, etc., and 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 smooth flow control.

[0135] 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, 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. 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 target duty cycle satisfies the cooling needs of all components to be cooled; the water pump duty cycle demand is determined to be an increasing demand or a decreasing demand based on the size of the current water pump duty cycle and the target water pump duty cycle; the control strategy to be executed is determined based on this demand. If it is an increasing demand, the first control strategy is executed; if it is a decreasing demand, the second control strategy is executed; according to different control strategies, the increasing gradient is determined to increase the current water pump duty cycle or the decreasing gradient is determined to decrease the current water pump duty cycle to obtain an updated water pump duty cycle, and the water pump duty cycle can be adjusted and controlled in real time based on different duty cycle demands. Therefore, this method not only considers temperature but also pressure to control the water pump. It can maintain a stable flow rate by continuously controlling the change gradient of the water pump duty cycle, preventing the sudden increase in water pressure caused by a large increase or decrease in flow rate, which can damage components such as pipes, extend the service life of the cooling system, and does not require the installation of a water pressure sensor, thereby reducing vehicle costs.

[0136] 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 includes:

[0137] A data acquisition module 210 is used to obtain actual temperatures of multiple components to be cooled and a water pump duty cycle;

[0138] A first determination module 220 is configured to determine a target duty cycle of the water pump based on each actual temperature;

[0139] A second determining module 230 is configured to determine a water pump duty cycle requirement based on the water pump target duty cycle and the water pump current duty cycle;

[0140] The strategy execution module 240 is configured 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;

[0141] an output calculation module 250, configured to calculate the output according to the updated water pump duty cycle;

[0142] The operation control module 260 is used to control the water pump according to the output.

[0143] Optionally, the embodiment of the present application 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 above-mentioned electric vehicle water pump control method embodiment is implemented, and the same technical effect can be achieved. To avoid repetition, it will not be described here.

[0144] The processor is the processor in the electronic device described in the above embodiment. The memory is a readable storage medium, including computer-readable storage media such as computer read-only memory (ROM), random access memory (RAM), a magnetic disk, or an optical disk. The memory can be an external storage device of the vehicle, such as a plug-in hard drive or smart memory card equipped on the vehicle, or 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 about to be output.

[0145] 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.

[0146] 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.

[0147] It should be noted that, in this article, the terms "comprise", "include" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, an element defined by the statement "comprises a ..." does not exclude the presence of other identical elements in the process, method, article or device comprising the element. In addition, it should be noted 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 the opposite 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.

[0148] Through the description of the above embodiments, those skilled in the art can clearly understand that the above-mentioned embodiment methods can be implemented by means of software plus the necessary general hardware platform. Of course, they can also be implemented by hardware, but in many cases the former is a more preferred embodiment. Based on this understanding, the technical solution of this application, or the part that contributes to the existing technology, can be embodied in the form of a software product. This computer software product is stored in a storage medium (such as ROM / RAM, magnetic disk, optical disk), and includes a number of instructions for enabling a terminal (which can be a mobile phone, computer, server, air conditioner, or network device, etc.) to execute the methods described in each embodiment of this application.

[0149] 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 this application, ordinary technicians in this field can also make many forms without departing from the purpose of this application and the scope of protection of the claims, all of which are within the protection of this application.

Claims

1. A water pump control method for an electric vehicle, applied to a thermal management system, wherein the thermal management system includes a water pipe, 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 the demand is rising, the first control strategy is executed to obtain the updated water pump duty cycle and calculate the output. The first control strategy includes: step S201, defining the threshold range of the water pump duty cycle x and the rising 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 water pump duty cycle, respectively; step S203, according to The current duty cycle of the water pump determines the threshold range of 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 water pump duty cycle; step S206, determining whether the updated water pump duty cycle reaches the water pump target duty cycle; step S207, if not, using the updated water pump duty cycle as the current water pump duty cycle, and repeating steps S203 to S206; step S208, if yes, outputting the updated water pump duty cycle; If the demand is decreasing, the second control strategy is executed to obtain an updated water pump duty cycle and calculate the output. 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, 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, corresponding to the fifth gradient value, the sixth gradient value, the seventh gradient value, and the eighth gradient value of the decreasing adjustment amount y1 of the current water pump duty cycle, respectively; step S303, Determine the threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S304, determine the gradient value of the downward adjustment amount y1 according to the threshold range; Step S305, adjust 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, determine whether the updated duty cycle of the water pump reaches the target duty cycle of the water pump; Step S307, if not, use the updated duty cycle of the water pump as the current duty cycle of the water pump, and repeat Steps S303 to S306; Step S308, if yes, output the updated duty cycle of the water pump; 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: 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.

3. The water pump control method of an electric vehicle according to claim 1, 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 value 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.

4. 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 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 the threshold temperature level; Comparing the actual temperature of each component to be cooled with a preset threshold temperature to obtain a 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; 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.

5. 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 a temperature signal of each component to be cooled by a vehicle controller in the electric vehicle to obtain a plurality of 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.

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 actual temperature includes: If the vehicle controller in the electric vehicle receives a vehicle power-off signal, the target duty cycle of the water pump is 0.

7. A water pump control system for an electric vehicle, characterized in that: The system comprises: A data acquisition module, used to obtain actual temperatures of multiple components to be cooled and a water pump duty cycle; a first determining module, configured to determine a target duty cycle of the water pump based on each of the actual temperatures; A second determining module is used to determine the water pump duty cycle increase or decrease requirement according to the water pump target duty cycle and the water pump current duty cycle; The strategy execution module is configured to execute a first control strategy to obtain an updated water pump duty cycle if the demand is rising. The first control strategy includes: step S201, defining a threshold range of the water pump duty cycle x and an 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, corresponding to a first gradient value, a second gradient value, a third gradient value, and a fourth gradient value of the increase adjustment amount y of the current water pump duty cycle, respectively; step S203 , determine the threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; step S204, determine the gradient value of the rising adjustment amount y according to the threshold range; step S205, increase the current duty cycle of the water pump according to the gradient value to obtain an updated water pump duty cycle; step S206, determine whether the updated water pump duty cycle reaches the water pump target duty cycle; step S207, if not, use the updated water pump duty cycle as the current duty cycle of the water pump, and repeat steps S203 to S206; step S208, if so, output the updated water pump duty cycle If the demand is for a decrease, the second control strategy is executed to obtain an updated duty cycle of the water pump, and the second control strategy includes: step S301, defining the threshold range of the water pump duty cycle x1 and the decrease adjustment amount y1 of the current duty cycle of the water pump, 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 correspond to the fifth gradient value, the sixth gradient value, the seventh gradient value and the eighth gradient value of the decrease adjustment amount y1 of the current duty cycle of the water pump, respectively; step S303, based on Determine the threshold range of the current duty cycle of the water pump according to the current duty cycle of the water pump; Step S304, determine the gradient value of the downward adjustment amount y1 according to the threshold range; Step S305, adjust 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, determine whether the updated duty cycle of the water pump reaches the target duty cycle of the water pump; Step S307, if not, use the updated duty cycle of the water pump as the current duty cycle of the water pump, and repeat Steps S303 to S306; Step S308, if yes, output the updated duty cycle of the water pump; an output calculation module, configured to calculate the output according to the updated water pump duty cycle; The operation control module is used to control the water pump according to the output.

8. A vehicle, characterized in that: The method comprises a processor, a memory, and a program or instruction stored in the memory and executable on the processor, wherein the program or instruction, when executed by the processor, implements the steps of the water pump control method of the electric vehicle as described in any one of claims 1 to 6.

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