Pump and method of controlling the same

Abstract

The present application provides a pump and a control method thereof. In the dry running detection step, when the pump is detected in a dry running state, the pump is switched to a recovery attempt step. In the recovery attempt step, the rotation speed of the pump is reduced to a recovery attempt speed, and after maintaining the pump at the recovery attempt speed for a recovery attempt time threshold, the rotation speed is increased to a detection attempt speed to enter a dry running detection attempt step. The detection attempt speed is at least 800 rotations per minute faster than the recovery attempt speed. The recovery attempt time threshold is not less than 2 seconds and not more than 8 minutes. The pump can intelligently handle priming of the pump to effectively recover the pump to a normal working state.

Description

Technical Field

[0001] This application relates to equipment for conveying liquids, and more particularly to pumps and methods for controlling them. Background Technology

[0002] When the coolant is insufficient, the cooling system cannot be completely filled, and air will fill the gaps. If the pump operates with insufficient coolant or only a small amount present, dry running will occur. Prolonged dry running will lead to excessive wear on the water pump.

[0003] A method for dry-run protection of an electronic water pump is disclosed in invention patent application publication No. CN116006450A. When the electronic water pump of the target vehicle is in operation, the rotational speed of the electronic water pump is detected; when the rotational speed of the electronic water pump exceeds a first threshold, the torque current of the electronic water pump is detected; when the torque current of the electronic water pump meets a first dry-run condition, the electronic water pump is determined to be in a dry-run state, and dry-run protection is performed on the electronic water pump.

[0004] However, as Figure 5 As shown, under dry-run protection mode, after the pump stops for a rest period of time T1, an attempt is made to detect dry running within a detection time threshold T2. The detection time threshold T2 is very short, making it difficult for the pump to provide sufficient driving force to push the coolant in. For example, when replacing an old pump with a new one at a service station, if the coolant in the cooling system is insufficient, the new pump may trigger the protection mechanism due to dry running, causing it to malfunction. In this situation, the pump's driving force is insufficient to deliver coolant into the system. Without specialized equipment to inject coolant, it is difficult to complete the maintenance of the cooling system. Summary of the Invention

[0005] This application addresses at least one technical problem existing in the prior art.

[0006] This application provides a pump control method, which includes: The dry-run detection step involves switching the pump to the recovery attempt step when it is detected that the pump is in a dry-run state. In the attempted recovery step, the pump speed is reduced to the attempted recovery speed, and the pump is kept running at the attempted recovery speed until the attempted recovery time threshold is reached. Then the speed is increased to the attempted detection speed to enter the attempted dry run detection step. The detection speed is at least 800 revolutions per minute faster than the recovery speed; and The threshold for attempted recovery time is no less than 2 seconds and no more than 8 minutes.

[0007] In some specific embodiments, in the dry run detection step, if the pump is still detected to be in a dry run state after the attempt detection time threshold is reached, the process switches to the recovery attempt step.

[0008] The threshold for the attempt detection time is no more than 5 seconds;

[0009] The attempt detection speed is at least 1000 rpm faster than the attempt recovery speed, and the attempt recovery speed is less than the dry-run detection speed threshold.

[0010] The dry rotation detection speed threshold is not less than 4000 rpm.

[0011] In some specific embodiments, in the dry running detection step, if the pump is still detected to be in a dry running state after a preset continuous dry running time threshold, the operation of the pump is stopped.

[0012] The continuous dry running time threshold is not less than 8 minutes, and the dry running detection speed threshold is not greater than 9800 rpm.

[0013] In some specific implementations, the attempted recovery time threshold is not less than 3 seconds and not more than 7 minutes, the continuous dry running time threshold is not less than 9 minutes and not more than 60 minutes, and the dry running detection speed threshold is not more than 8000 rpm.

[0014] In some specific implementations, the continuous dry running time threshold is not less than 10 minutes and not more than 30 minutes, and the attempted recovery time threshold is not less than 4 seconds and not more than 6 minutes.

[0015] In some specific implementations, the attempted recovery time threshold is not less than 5 seconds and not more than 5 minutes. In the dry run detection step and / or the attempted dry run detection step, if the pump current is detected to be less than the current threshold, it indicates that the pump is in a dry run state.

[0016] In some specific implementations, the attempted recovery time threshold is not less than 6 seconds and not more than 4 minutes, and the current threshold is related to the pump speed; the lower the pump speed, the lower the current threshold.

[0017] In some specific implementations, the attempted recovery time threshold is not less than 8 seconds and not more than 3 minutes. In the dry run detection step, if it is detected that the pump is not in a dry run state, the system switches to the normal operation step, in which the pump operates in response to the required speed.

[0018] In some specific implementations, the attempted recovery time threshold is not less than 10 seconds and not more than 2 minutes, and in the dry run detection step, the pump operates in response to a demand speed, which is greater than the dry run detection speed threshold.

[0019] On the other hand, this application provides a water pump, which includes an armature and a controller, wherein the controller controls the operation of the armature according to the aforementioned method.

[0020] According to the technical solution of this application, when the pump operates at the attempted recovery speed, it generates little heat and can produce the necessary negative pressure, allowing coolant to flow into the pump rapidly. The coolant carries away the pump's heat after entering, helping to suppress overheating and thus restoring the pump to normal operation. In this case, if a dry-run test is performed again, it will be found that the pump is not in a dry-running state. Therefore, by operating according to the attempted recovery procedure, coolant can be effectively injected without special priming equipment, air in the pump can be expelled, and the pump can be restored to normal operating conditions. Attached Figure Description

[0021] The specific embodiments of this application are described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram showing a specific embodiment of a pump control method is displayed; Figure 2 This diagram illustrates the time-speed relationship of a pump according to a specific embodiment. Figure 3 This diagram illustrates the time-speed relationship of a pump according to another specific embodiment. Figure 4 A schematic diagram of a pump according to one specific embodiment is shown; Figure 5 This diagram illustrates the time-speed relationship of a pump using a conventional control method. Detailed Implementation

[0022] According to a specific embodiment of this application, a pump control method is as follows: Figure 1 As shown, this control method can be applied to Figure 4 The pump 800 is shown. Pump 800 includes an armature 80, a controller 82, and multiple sensors. These sensors include, but are not limited to, a speed sensor 84, a current sensor 86, and (though not shown, may include) a temperature sensor. These sensors are signal-connected to the controller 82, enabling the controller 82 to receive sensor signals and thus make necessary control responses in real time. The controller 82 has an internal memory 88, including permanent memory, for storing data that will not be lost due to power failure. In some specific embodiments, the controller 82 controls the armature operation according to the aforementioned method.

[0023] The pump control method includes a conventional power-on and start-up step 11. In the power-on and start-up step 11, the controller 82 completes a series of start-up processes, obtains the required speed r according to the current situation, and controls the pump 800 to operate according to the required speed r. After the pump 800 starts operating, it enters the dry-run detection step 12 under certain conditions.

[0024] Dry running is an abnormal situation in pump operation, referring to the pump operating without water or with insufficient water flow. This can lead to overheating and rapid wear. Several mature control methods exist in the field to detect dry running, identifying whether a pump is running dry through specific detection steps. For example, the pump's speed and current can be used to determine if it is running dry. If the current is less than a certain threshold at a given speed, it indicates dry running. In some specific implementations, detecting dry running includes detecting that the pump current is less than a current threshold. The current threshold is related to the pump's speed; the lower the pump speed, the lower the current threshold. The corresponding speed and current thresholds can be calibrated experimentally.

[0025] Technicians discovered that at higher pump speeds, the relationship between speed and current can be monitored to accurately determine if dry running has occurred. This method avoids inaccurate dry running detection at lower speeds (e.g., less than 2000 rpm). Typically, the required speed *r* is greater than the dry running detection speed threshold. The dry running detection speed threshold is no less than 4000 rpm and no more than 9800 rpm. For example, the dry running detection speed thresholds are 6000 rpm, 7000 rpm, 7600 rpm, or 8000 rpm.

[0026] In the dry running detection step 12, pump 800 usually continues to operate in response to the demand speed r. If the demand speed r is not greater than the dry running detection speed threshold, it is usually necessary to control the speed of pump 800 to be increased above the dry running detection speed threshold. When pump 800 is detected to be in a dry running state, pump 800 is switched to attempt recovery step 13.

[0027] In the recovery attempt step 13, the speed of pump 800 is reduced to the recovery attempt speed R1. After maintaining pump 800 at the recovery attempt speed R1 for the recovery attempt time threshold, the speed is increased to the detection attempt speed R2 to proceed to the dry-run detection attempt step 2. The recovery attempt speed R1 is less than the dry-run detection speed threshold. When pump 800 operates at the recovery attempt speed R1, its heat generation is low, and it can generate the necessary negative pressure to allow coolant to quickly flow into the pump 800 through the cooling system. Once coolant is in the pump 800, the coolant dissipates heat, suppressing excessive heat generation and restoring normal operation. In this case, if pump 800 then proceeds to the dry-run detection attempt step 2, it will be detected that pump 800 is not in a dry-running state. Controlling pump 800 to operate according to the recovery attempt step 13 during dry-running is suitable for quickly removing air from pump 800, allowing it to return to normal operating conditions.

[0028] In some specific embodiments, the dry-run detection step 2 includes two sub-steps: dry-run detection sub-step 20 and continuous dry-run judgment sub-step 22. In some specific embodiments, in the dry-run detection step 2 (e.g., in the dry-run detection sub-step 20), if it is detected that the pump 800 is not in a dry-run state, then the system switches to the normal operation step 3, in which the pump 800 operates in response to the required speed r. The time-speed relationship of the pump 800 under this condition is illustrated in the diagram below. Figure 2 As shown. The recovery time threshold should be no less than 2 seconds and no more than 8 minutes. For example, the recovery time threshold can be 3 seconds, 4 seconds, 5 seconds, 6 seconds, 7 seconds, 8 seconds, 10 seconds, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 6 minutes, or 8 minutes. After a recovery period of an appropriate time, proceed to step 2 of the dry-run test, and switch to the regular operation step 3 in a timely manner after the normal operating conditions are restored.

[0029] In the dry-run detection sub-step 20, if pump 800 is still detected to be in a dry-running state after reaching the attempt detection time threshold, the process switches to the attempt recovery step 13. The attempt detection speed R2 is at least 800 rpm faster than the attempt recovery speed R1. For example, the attempt detection speed R2 is 1000 rpm, 1600 rpm, 2000 rpm, or 2600 rpm faster than the attempt recovery speed R1. The attempt detection time threshold is less than the attempt recovery time threshold. The attempt detection time threshold limits the operation time of the dry-run detection sub-step 20, preventing unnecessary damage to pump 800 caused by prolonged operation at a high attempt detection speed R2. The attempt detection time threshold is no greater than 5 seconds. For example, the attempt detection time threshold is 4 seconds, 3 seconds, or 2 seconds.

[0030] In the continuous dry running judgment sub-step 22, if pump 800 is still detected to be in a dry running state after a preset continuous dry running time threshold, then the operation of pump 800 is stopped. Under this condition, the time-speed relationship of pump 800 is shown in the following diagram. Figure 3 As shown. The continuous dry running time threshold is not less than 8 minutes and not more than 60 minutes. For example, the continuous dry running time thresholds are 9 minutes, 10 minutes, 15 minutes, 20 minutes, 26 minutes, and 30 minutes. Because the continuous dry running judgment sub-step 22 appropriately limits the dry running time, it avoids unnecessary and lengthy attempts to recover in the event of unexpected situations such as a complete lack of coolant. If venting is difficult to achieve under the limited conditions, pump 800 is stopped, effectively preventing excessive wear of pump 800.

[0031] Pump 800 being in a dry-running state indicates that the controller determines that pump 800 is in a dry-running state based on predetermined signals. In some specific embodiments, if the current of pump 800 is detected to be less than a current threshold in dry-running detection step 12 and / or attempted dry-running detection step 2, it indicates that pump 800 is in a dry-running state. The current threshold is related to the rotational speed of pump 800; the lower the rotational speed of pump 800, the lower the current threshold.

[0032] Despite the above explanation, the scope of patent protection for this application is defined by the claims.

Claims

1. A pump control method, characterized in that, It includes: The dry-run detection step involves switching the pump to the recovery attempt step when it is detected that the pump is in a dry-run state. In the attempted recovery step, the pump speed is reduced to the attempted recovery speed, and the pump is kept running at the attempted recovery speed until the attempted recovery time threshold is reached. Then the speed is increased to the attempted detection speed to enter the attempted dry run detection step. The detection speed is at least 800 revolutions per minute faster than the recovery speed; and The threshold for attempted recovery time is no less than 2 seconds and no more than 8 minutes.

2. The method according to claim 1, wherein, In the dry run detection step, if the pump is still detected to be in a dry run state after the detection time threshold is reached, then switch to the recovery step. The threshold for the attempt detection time is no more than 5 seconds; The attempt detection speed is at least 1000 rpm faster than the attempt recovery speed, and the attempt recovery speed is less than the dry-run detection speed threshold. The dry rotation detection speed threshold is not less than 4000 rpm.

3. The method according to claim 2, wherein, In the dry running detection step, if the pump is still detected to be in a dry running state after a preset continuous dry running time threshold, the operation of the pump is stopped. The continuous dry running time threshold is not less than 8 minutes, and the dry running detection speed threshold is not greater than 9800 rpm.

4. The method according to claim 3, wherein, The threshold for attempted recovery time is no less than 3 seconds and no more than 7 minutes, the threshold for continuous dry running time is no less than 9 minutes and no more than 60 minutes, and the threshold for dry running detection speed is no more than 8000 rpm.

5. The method according to claim 3, wherein, The threshold for continuous dry running time is not less than 10 minutes and not more than 30 minutes, and the threshold for attempted recovery time is not less than 4 seconds and not more than 6 minutes.

6. The method according to claim 1, wherein, The attempt recovery time threshold is not less than 5 seconds and not more than 5 minutes. In the dry run detection step and / or the attempt dry run detection step, if the pump current is detected to be less than the current threshold, it indicates that the pump is in a dry run state.

7. The method according to claim 6, wherein, The attempted recovery time threshold is not less than 6 seconds and not more than 4 minutes. The current threshold is related to the pump speed, and the lower the pump speed, the lower the current threshold.

8. The method according to claim 1, wherein, The attempt recovery time threshold is not less than 8 seconds and not more than 3 minutes. In the attempt dry run detection step, if it is detected that the pump is not in a dry run state, the process switches to the normal operation step, in which the pump operates in response to the required speed.

9. The method according to claim 2, wherein, The attempted recovery time threshold is not less than 10 seconds and not more than 2 minutes. In the dry run detection step, the pump operates in response to the required speed, which is greater than the dry run detection speed threshold.

10. A water pump, comprising an armature and a controller, characterized in that, The controller controls the armature operation according to any one of claims 1 to 9.

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