Control method for counter-rotating axial-flow type electronic water pump

Abstract

The invention relates to the technical field of automobile electronic water pumps. A control method for a counter-rotating axial-flow type electronic water pump comprises the steps that an efficiency curve graph of the electronic water pump is obtained through a simulation method, and data are stored in a control unit; the temperature of a cooling area required by the electronic water pump is detected and acquired and is transmitted to the signal processing unit; the signal processing unit judges the heat dissipation level according to the cooling area and transmits the heat dissipation level to the control unit; the control unit adjusts the rotating speeds of the first rotor and the second rotor according to the heat dissipation level; the rotating speeds of the first rotor and the second rotor are adjusted according to the temperature of the cooling area until cooling is not needed. According to the control method for the rotary axial-flow type electronic water pump, the axial installation space can be fully utilized, the requirement for the radial space size is reduced, meanwhile, the flow of cooling liquid is increased, the cooling effect of a heating part is improved, and loss is low. The technical problems that in the prior art, an electronic water pump is low in efficiency, obvious in attenuation and insufficient in performance are solved.

Description

Technical Field

[0001] This invention relates to the field of automotive electronic water pump technology, and in particular to a control method for a rotary axial flow electronic water pump. Background Technology

[0002] The electric water pump is a core component of a vehicle's thermal management system. It is responsible for driving the coolant circulation to dissipate heat from major heat-generating components such as the motor and battery, ensuring the normal operation of the vehicle's powertrain. If the electric water pump performs poorly, it can lead to overheating of the motor or battery, potentially causing a safety hazard.

[0003] In existing technologies, water pumps are typically single centrifugal pumps with simple control strategies. They primarily rely on temperature feedback from temperature sensors to control the flow rate of a single pump, resulting in low efficiency at both high and low flow rates. A typical efficiency curve for a traditional single centrifugal pump is shown below. Figure 1 As shown, the efficiency first increases and then decreases. The efficiency is low and the loss is high when the flow rate is large or small. Figure 1 The curve shown indicates that the optimal efficiency point is at a speed of 5000 rpm and a flow rate of 20 L / min, where the efficiency is relatively high, around 70%. However, if the flow rate deviates from this range, for example, if the required flow rate is 40 L / min, the efficiency of the pump will only be around 40%, showing a significant decrease. Summary of the Invention

[0004] This invention provides a control method for a rotary axial flow electric water pump that can fully utilize axial installation space, reduce radial space requirements, increase coolant flow rate, improve cooling effect of heat-generating components, and reduce losses; it solves the technical problems of low efficiency, significant attenuation, and insufficient performance of existing electric water pumps.

[0005] The above-mentioned technical problem of the present invention is solved by the following technical solution: a control method for a rotary axial flow electronic water pump, wherein the electronic water pump includes an inlet pipe and an outlet pipe, and a first stator, a first rotor, a second rotor and a second stator are sequentially arranged between the inlet pipe and the outlet pipe, wherein the first rotor and the second rotor rotate in opposite directions; When controlling the rotational speeds of the first and second rotors within the water pump, the following method shall be followed: Step 1: Obtain the efficiency curve of the electronic water pump through simulation or experimentation, and store the data in the control unit; Step 2: The detection unit acquires the temperature of the cooling area required by the electronic water pump and transmits it to the signal processing unit; Step 3: The signal processing unit determines the heat dissipation level based on the cooling area and transmits the result to the control unit; Step 4: The control unit adjusts the speed of the first and second rotors based on the heat dissipation level and the data in the control unit in Step 1. Step 5: Repeat steps 2 to 4 above, adjusting the speeds of the first and second rotors according to the temperature of the cooling zone until cooling is no longer required.

[0006] The inlet pipe, the first-stage stator system, the rotor system, the second-stage stator system, and the outlet pipe form a complete flow channel. A negative pressure is created inside, drawing the coolant in through the inlet pipe. First, the coolant passes through the first stator structure, where it undergoes pre-swirl to reduce flow losses as it enters the rotor casing, improving performance. Next, the coolant flows through the first rotor structure, where its kinetic and pressure potential energy are increased by the work done by the first rotor. It then enters the second rotor structure, where its kinetic and pressure potential energy are further increased by the work done by the second rotor, resulting in two pressurization boosts to improve performance. Finally, it enters the second stator casing, where its rectifier converts kinetic energy into pressure potential energy, further increasing the head. The coolant is then pumped out through the outlet pipe and enters the heating element pipe. The two-stage rotor system enhances the pump's performance and, in conjunction with the stator structure, further increases the head.

[0007] The efficiency curve of the axial flow electric water pump can be obtained through simulation or experimentation and stored in advance in the control unit. The control unit can then determine the optimal speed of the first and second rotors by looking up tables / retrieval or other methods, thereby improving efficiency.

[0008] Preferably, the efficiency curve in the first step is plotted using the following method: First, a model is established, including the inlet pipe, the first stator, the first rotor, the second rotor, the second stator, and the flow domain within the outlet pipe; second, the entire flow domain model is meshed using finite element methods; then, fluid numerical values ​​are set and simulated, including the rotational speed of the first rotor, the rotational speed of the second rotor, and the outlet flow rate, while monitoring the rotor torque and the total pressure difference between the inlet and outlet; finally, based on the calculated information, efficiency curves of the first and second rotors at different rotational speeds are plotted.

[0009] Preferably, the cooling area is the engine area.

[0010] Preferably, the heat dissipation level can be divided into 5 levels, A, B, C, D, and E, with the heat dissipation requirement decreasing in that order. A represents the highest temperature and requires urgent heat dissipation, while E represents no heat dissipation required.

[0011] As a preferred method, the rotor speed is graded. The first rotor speed n1 has three levels: high, medium, and low. The second rotor speed n2 also has three levels: high, medium, and low. The efficiency curve is plotted based on the rotor speed grading.

[0012] When the heat dissipation level is A, heat dissipation is urgently needed, requiring the maximum flow rate Q1. By consulting a table / retrieving the electronic water pump efficiency curve, the optimal efficiency point corresponding to the Q1 flow rate is obtained. Furthermore, the corresponding rotor speeds for the first and second stages are n1 (high speed) and n2 (high speed), respectively. At this point, rapid heat dissipation and cooling are achieved, with the highest efficiency point at Q1. When the heat dissipation level is detected to decrease to B, faster heat dissipation is required, necessitating a larger flow rate Q2. By consulting a table / retrieving the electronic water pump efficiency curve, the optimal efficiency point corresponding to the Q2 flow rate is obtained. Furthermore, the corresponding rotor speeds for the first and second stages are n1 (high speed) and n2 (medium speed), respectively. When the heat dissipation level is detected to further decrease to C, only a slow speed is needed. For heat dissipation, a relatively small flow rate of Q3 is required. Similarly, by looking up the table / searching the electronic water pump efficiency curve, the optimal efficiency point corresponding to the flow rate of Q3 is obtained, and the corresponding first and second rotor speeds are n1 (medium) and n2 (high), respectively. When the heat dissipation level is further reduced to D, only heat preservation is needed, and the required flow rate is further reduced to Q4. By looking up the table / searching the electronic water pump efficiency curve, the optimal efficiency point corresponding to the flow rate of Q3 is obtained, and the corresponding first and second rotor speeds are n1 (medium) and n2 (medium), respectively. When the heat dissipation level is E, it is only necessary to avoid rotor reversal and damage to the motor. The speed is adjusted to n1 (low) and n2 (low), and the rotors rotate at the lowest speed.

[0013] Therefore, the control method for a counter-rotating axial-flow electronic water pump of the present invention has the following advantages: It effectively improves pump performance through a two-stage counter-rotating axial-flow structure, and achieves rectification and pressurization effects through the front and rear first stator structures and the second stator structure, further increasing the head. By monitoring the engine temperature in real time and comparing the efficiency curve to adjust the flow output, the characteristics of the two-stage rotor of the counter-rotating axial-flow electronic water pump are fully utilized, achieving the highest efficiency output under various temperatures and heat dissipation requirements, reducing power consumption, and effectively solving the problems of low efficiency and high power consumption of single pumps in the prior art. Attached Figure Description

[0014] Figure 1 This is an efficiency curve of a single centrifugal pump in the existing technology.

[0015] Figure 2 yes Figure 1 A schematic diagram of a medium-sized electronic water pump.

[0016] Figure 3 This is a schematic diagram of the efficiency curve of a rotary axial flow electronic water pump.

[0017] Figure 4 It is a flowchart of the control method. Detailed Implementation

[0018] The technical solution of the invention will be further described in detail below through embodiments and in conjunction with the accompanying drawings.

[0019] Example: like Figure 2 As shown, a control method for a rotary axial flow electric water pump includes an inlet pipe 1 and an outlet pipe 7 located at both ends. A first stator system, a rotor system, and a second stator system are arranged between the inlet pipe 1 and the outlet pipe 7.

[0020] The first stator system includes a first stator housing 2, in which a first stator 11 is integrally injection molded. A first shaft hole is opened in the center of the first stator 11, and a first motor 3 is fixed in the first shaft hole by ultrasonic welding. Of course, it can also be fixed and connected by thread or glue.

[0021] The second stator system includes a second stator housing 6, within which a second stator 8 is integrally injection molded. A second shaft hole is provided in the center of the second stator 8, and a second motor 5 is fixed in the second shaft hole by ultrasonic welding.

[0022] The rotor system includes a rotor casing 4, within which a first rotor 10 and a second rotor 9 are mounted. Gaps are maintained between the inner wall of the rotor casing 4 and both the first rotor 10 and the second rotor 9 to ensure rotation within the casing. The first rotor 10 can be directly press-fitted to the shaft of the first motor, or it can be connected using a key, coupling, or other methods, as long as the motor can drive the rotor to rotate normally. Similarly, the second rotor 9 is driven to rotate by the second motor 5. Figure 4 As shown, the first rotor 10 and the second rotor 9 are mirror images of each other, but rotate in opposite directions.

[0023] One end of the first stator casing 2 is connected to the inlet pipe 1 by butt welding or ultrasonic welding. The other end of the first stator casing 2 is also connected to one end of the rotor casing 4 by butt welding or ultrasonic welding. The other end of the rotor casing 4 is connected to one end of the second stator casing 6 by butt welding or ultrasonic welding. The other end of the second stator casing 6 is also connected to the outlet pipe 7 by butt welding or ultrasonic welding.

[0024] The above-mentioned electronic water pump uses the following method for flow control in order to achieve maximum efficiency: Step 1: Obtain the efficiency curve of the counter-rotating axial flow electric water pump through numerical simulation. The main steps are as follows: a. Establish a flow domain model for the entire counter-rotating axial flow electric water pump.

[0025] b. Perform finite element mesh generation on the entire watershed model.

[0026] c. Perform fluid numerical simulation calculations and related settings; key settings include the rotational speeds of the first and second rotors, the flow rate of the outlet pipe, and monitoring the rotor torque and the total pressure difference between the inlet and outlet.

[0027] d. Post-processing. Based on the relevant information obtained in step c, plot the efficiency curves of the first and second stage rotors at different speeds, as shown in the attached figure. Figure 3 As shown.

[0028] In this embodiment of the invention, both the first rotor and the second rotor have three preset speed settings: high, medium, and low. The high speed is 4000 rpm, the medium speed is 2000 rpm, and the low speed is 500 rpm. (See attached diagram.) Figure 3 The performance curve shown has the following characteristics: 1. With the first stage rotor operating at medium speed and the second stage rotor operating at medium speed, the highest efficiency point is 10L / min; 2. With the first stage rotor at medium speed and the second stage rotor at high speed, the highest efficiency point is 20L / min; 3. With the first stage rotor at high speed and the second stage rotor at medium speed, the highest efficiency point is 30L / min; 4. With the first stage rotor at high speed and the second stage rotor at high speed, the highest efficiency point is 40L / min; 5. The first stage rotor is at its lowest speed, and the second stage rotor is at its lowest speed. This consumes the least power and simply prevents the rotor from reversing.

[0029] The above data is stored in the control unit so that the control unit can make the best selection based on the data.

[0030] Step 2: The detection unit (which can be a temperature sensor) acquires the engine zone temperature T1 and transmits it to the signal processing unit.

[0031] Step 3: The signal processing unit determines the heat dissipation level based on the cooling area. The heat dissipation level is divided into five levels: A, B, C, D, and E, with level A being the highest and decreasing from A to E. If the obtained engine temperature is 300℃, the heat dissipation level is determined to be Class A (the temperature that urgently needs to be cooled can be selected according to the heat resistance level of different parts of the engine and the model), and then transmitted to the control unit.

[0032] Step 4: The control unit determines the required heat dissipation flow rate of 40L / min based on the heat dissipation level. By looking up the table / searching the efficiency curve, it determines the speed corresponding to the optimal efficiency at this time: the first rotor speed is at the high speed and the second rotor speed is at the high speed. It then controls the first motor and the second motor to output the corresponding power. At this time, the entire pump system circulates rapidly at a flow rate of 40L / min to cool the system. At this time, it has the highest efficiency of 70%.

[0033] Step 5: The detection unit continuously monitors the engine area temperature. When it drops to 250℃, it transmits the temperature signal to the signal processing unit. The signal processing unit determines that the heat dissipation level has decreased to level B and transmits this information to the control unit. Based on the heat dissipation level, the control unit determines that the required heat dissipation flow rate is 30L / min. By looking up a table / retrieving an efficiency curve, it determines the optimal speed corresponding to this point: the first rotor speed is at high speed and the second rotor speed is at medium speed. The control unit then controls the first and second motors to output the corresponding power. At this point, the entire pump system circulates rapidly at a flow rate of 30L / min to cool the system, achieving a maximum efficiency of 70%. The detection unit continuously monitors the engine area temperature. When it drops to 150℃, it transmits the temperature signal to the signal processing unit. The signal processing unit determines that the heat dissipation level has decreased to level C and transmits this information to the control unit. Based on the heat dissipation level, the control unit determines that the required heat dissipation flow rate is 20L / min. By looking up a table / retrieving an efficiency curve, it determines the optimal speed corresponding to this point: the first rotor speed is at medium speed and the second rotor speed is at high speed. The control unit then controls the first and second motors to output the corresponding power. At this point, the entire pump system circulates at a flow rate of 20L / min to cool the system, achieving a maximum efficiency of 70%. Repeat the above steps until cooling is no longer needed. At this point, control both the first-stage rotor and the second-stage rotor to run at low speeds to avoid reverse rotation. The entire system will then consume the least amount of power.

[0034] The specific embodiments described herein are merely illustrative of the concept of the invention. Those skilled in the art to which this invention pertains may make various modifications or additions to the described specific embodiments or use similar methods to replace them, without departing from the spirit of the invention or exceeding the scope defined by the appended claims.

Claims

1. A control method for a rotary axial flow electronic water pump, characterized in that: The electric water pump includes an inlet pipe and an outlet pipe. Between the inlet pipe and the outlet pipe, a first stator, a first rotor, a second rotor, and a second stator are arranged in sequence, wherein the first rotor and the second rotor rotate in opposite directions. When controlling the rotational speeds of the first and second rotors within the water pump, the following method shall be followed: Step 1: Obtain the efficiency curve of the electronic water pump through simulation or experimentation, and store the data in the control unit; Step 2: The detection unit acquires the temperature of the cooling area required by the electronic water pump and transmits it to the signal processing unit; Step 3: The signal processing unit determines the heat dissipation level based on the cooling area and transmits the result to the control unit; Step 4: The control unit adjusts the speed of the first and second rotors based on the heat dissipation level and the data in the control unit in Step 1. Step 5: Repeat steps 2 to 4 above, adjusting the speeds of the first and second rotors according to the temperature of the cooling zone until cooling is no longer required.

2. The control method for a rotary axial flow electronic water pump according to claim 1, characterized in that: The efficiency curves in the first step are plotted using the following method: First, a model is established, including the inlet pipe, the first stator, the first rotor, the second rotor, the second stator, and the flow domain within the outlet pipe. Second, the entire flow domain model is meshed using finite element methods. Then, fluid parameters are set and simulated, including the rotational speed of the first rotor, the rotational speed of the second rotor, and the outlet flow rate, while monitoring the rotor torque and the total pressure difference between the inlet and outlet. Finally, based on the calculated information, efficiency curves of the first and second rotors at different rotational speeds are plotted.

3. The control method for a rotary axial flow electronic water pump according to claim 1, characterized in that: The cooling area is the engine area.

4. The control method for a rotary axial flow electronic water pump according to claim 1, characterized in that: The heat dissipation levels can be divided into 5 levels, A, B, C, D, and E, with the heat dissipation requirements decreasing in that order. A represents the highest temperature and requires urgent heat dissipation, while E represents no heat dissipation required.

5. The control method for a rotary axial flow electronic water pump according to claim 1, characterized in that: The rotor speeds are graded, with the first rotor speed n1 having three levels: high, medium, and low, and the second rotor speed n2 also having three levels: high, medium, and low. Efficiency curves are plotted based on the rotor speed grades.

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