Pump and method of controlling the same

Abstract

The application relates to a pump and a control method thereof. The pump comprises an armature and a controller. The controller controls the armature to operate according to the following method. According to the control method, when dry running is detected, the pump is controlled to perform a first mode step, the first mode step comprises controlling the pump to operate at a first speed, accumulating the time of pump operation as a first mode time, and when the first mode time reaches a first mode threshold, the pump is controlled to exit the first mode step. The method can effectively deal with the dry running problem.

Description

Technical Field

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

[0002] When the coolant level in a car's cooling system is insufficient, it means there are gaps within the system that are not filled with enough coolant and are instead occupied by air. If the pump is filled with air without enough coolant, it will cause the pump to run dry. Prolonged dry running can cause irreversible damage to the 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 is greater than 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. Summary of the Invention

[0004] This application addresses at least one technical problem existing in the prior art.

[0005] This application provides a pump control method, which includes: When dry running is detected, the pump is controlled to perform a first mode step. The first mode step includes controlling the pump to run at a first speed, accumulating the pump running time as the first mode current time, and controlling the pump to exit the first mode step when the first mode current time reaches a first mode threshold. The first mode threshold is greater than 5 minutes but not greater than 30 minutes, the first speed is not greater than 70% of the pump's rated speed, and the first speed is not less than 3000 rpm.

[0006] In some specific implementations, the first mode step includes: Controlling the pump to exit the first mode step while simultaneously disabling the first mode step; and / or The total dry running time of the pump throughout its entire lifespan is defined as the total dry running time. The first mode step is disabled when the total dry running time is not less than a total dry running threshold, where the total dry running threshold is greater than 60 minutes, the first speed is not greater than 60% of the pump's rated speed, and the first speed is not less than 3800 rpm; and / or When dry running is detected to have disappeared, the control pump operates at the required speed.

[0007] In some specific implementations, if dry running is detected and the first mode step is disabled, the pump is controlled to perform a normal dry running protection step. This normal dry running protection step includes controlling the pump to attempt operation when the rest period reaches a rest time threshold. The pump attempt to operate includes: The pump is controlled to operate at a trial speed greater than the first speed. If the dry running is detected to disappear, the pump is controlled to operate at the required speed. If the dry running is not detected to disappear after a predetermined trial operation time threshold, the pump is controlled to continue the conventional dry running protection steps. The rest time threshold is greater than 1 second, and the attempt operation time threshold is not greater than 5 seconds.

[0008] In some specific implementations, the total dry-run threshold is greater than 100 minutes and not greater than 800 minutes, the first mode threshold is greater than 6 minutes and not greater than 28 minutes, in the normal dry-run protection mode, the rest time threshold is greater than 2 seconds, the attempt operation time threshold is not greater than 2 seconds, and when the number of attempts to run the pump reaches the attempt number threshold, the pump is controlled to stop running, and the attempt number threshold is not less than 2.

[0009] In some specific implementations, the total dry-turn threshold is greater than 150 minutes and not greater than 450 minutes, the first mode threshold is greater than 10 minutes and not greater than 18 minutes, and the number of attempts threshold is not less than 6.

[0010] In some specific implementations, the total dry-turn threshold is greater than 160 minutes and not greater than 350 minutes, the first mode threshold is greater than 11 minutes and not greater than 16 minutes, and the number of attempts threshold is not less than 10.

[0011] In some specific implementations, the total dry-transfer threshold is greater than 180 minutes and not greater than 250 minutes, the first mode threshold is greater than 13 minutes and not greater than 15 minutes, and the number of attempts threshold is not greater than 800.

[0012] In some specific embodiments, detecting dry running includes detecting that the pump current is less than a current threshold, and controlling the pump to rest includes controlling the pump to stop operating or controlling the pump to reduce its operating speed to a resting speed, which is less than the first speed.

[0013] In some specific implementations, the current threshold is related to the pump speed, and the lower the pump speed, the lower the current threshold.

[0014] On the other hand, this application provides a pump that includes an armature and a controller, the controller controlling the operation of the armature according to the aforementioned method.

[0015] According to some specific embodiments of this application, when dry running is detected, the pump is controlled to operate in a first mode. This first mode operates at a relatively low speed for more than 5 minutes to purge air from the pump, allowing it to quickly enter normal operating conditions. The first mode is particularly helpful for adding coolant to an empty cooling system. If the empty cooling system is filled with air, controlling the pump to operate in the first mode will quickly purge the air and rapidly add coolant. The first speed of the pump operating in the first mode does not exceed 70% of the pump's rated speed, and the continuous operating time is less than 30 minutes. Appropriately limiting the speed and operating time in the first mode largely prevents excessive pump wear.

[0016] While operating the pump in the first mode improves the efficiency of adding coolant to an empty system while taking into account pump wear, it is understandable that this operation involves dry running, which can damage the pump. This application creatively employs protective measures to prevent excessive damage from unrestricted operation in the first mode. Firstly, the duration of each first-mode operation is limited, specifically, the time for each first-mode session must not exceed a predetermined threshold. This threshold prevents erroneous prolonged operation in the first mode. Secondly, the total dry-running time over the pump's entire lifespan is accumulated. When the total dry-running time is not less than the total dry-running threshold, it indicates that the pump's wear has reached its permissible limit, and continued operation in the first mode is likely to lead to failure. Therefore, continued operation in the first mode is prohibited to prevent excessive pump wear, thereby maximizing the pump's service potential and preventing unexpected excessive damage to the cooling system due to pump failure.

[0017] If a pump that is prohibited from continuing to operate in the first mode is not replaced but still needs to be operated, it will enter the normal dry run protection mode with reduced wear in order to attempt to resume operation under better protection and to maximize the pump's performance. Attached Figure Description

[0018] The specific embodiments of this application are described in detail below with reference to the accompanying drawings, wherein: Figure 1 A schematic diagram of a pump according to one specific embodiment is shown; Figure 2 A schematic flowchart of a pump control method according to a specific embodiment is shown; and Figure 3 This diagram illustrates the relationship between operating time and rotational speed of a pump in an exhaust scenario, according to a specific embodiment. Figure 4 This diagram illustrates the time-speed relationship of a pump in one specific embodiment when the pump is controlled according to the conventional dry-run protection procedure. Detailed Implementation

[0019] This application relates to a pump and a control method thereof, which can intelligently detect and handle dry running conditions of the pump. The following detailed description, in conjunction with the accompanying drawings and specific embodiments, further illustrates this application.

[0020] Please see Figure 1 As 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 a temperature sensor (though not shown, it may be included). The controller 82 internally houses a memory 88, including permanent memory, for storing data that will not be lost due to power failure.

[0021] The controller 82 controls the operation of the armature 80 according to a preset method, which can handle dry running situations. Dry running is an abnormal condition in pump operation, referring to the pump operating without water or with insufficient water volume, which may lead to overheating, wear, or even damage. Several mature control methods exist in the art for detecting dry running, identifying whether the pump is running dry through detection steps. For example, it can be determined by the pump's speed and current; if the current is less than a certain threshold at a certain speed, it indicates that the pump is running dry. In some specific embodiments, 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.

[0022] Technicians have found that dry running can be accurately determined by the relationship between pump speed and current when the pump speed is relatively high, which avoids inaccurate dry running determination when the speed is too low (e.g., less than 2,000 rpm).

[0023] If dry running is detected, the pump needs to be protected to prevent excessive wear under severe dry running conditions.

[0024] According to some specific embodiments of this application, if the pump is controlled to perform a first-mode step before the regular dry-run protection step is performed when dry running is detected, normal operation can be restored more efficiently. If the first-mode step is prohibited when dry running is detected, the pump is then controlled to perform the regular dry-run protection step.

[0025] Please refer to the following: Figure 2As shown, the pump control method 100 includes a start step 1. In start step 1, the pump is controlled to operate at a requested speed while simultaneously detecting whether it is dry running. If dry running is detected in start step 1, the pump 800 is controlled to enter a first mode step 10. The first mode step 10 includes a step 11 for obtaining the total dry running time, which represents the time the pump runs dry over its entire lifespan, for example, a parameter accumulated and stored in a memory beforehand. After obtaining the total dry running time step 11, a step 12 for determining the dry running time is included, in which it is determined whether the total dry running time is less than a total dry running threshold. If yes, the pump is controlled to perform a venting step 13; otherwise, the pump is controlled to perform a normal dry running protection step 30.

[0026] In the venting step 13, the pump 800 is controlled to operate at a first speed V1, and the pump operation time is accumulated and calculated as the current time Tv of the first mode. In some specific embodiments, in the venting step 13, the dry running time of the pump throughout its entire life cycle is also accumulated, i.e., the total dry running time. The total dry running time is stored in a permanent memory so that the record can still be maintained in the event of a power outage.

[0027] After exhaust step 13, a dry run detection step 15 and an exhaust time determination step 20 are performed. In dry run detection step 15, if dry run is detected to have disappeared, the system proceeds to normal operation step 16. In normal operation step 16, the pump is controlled to operate at the requested speed V0. If dry run is detected to still exist in dry run detection step 15, the system proceeds to exhaust time determination step 20. In exhaust time determination step 20, it is determined whether the current time Tv of the first mode is greater than the first mode sub-threshold. If not, the system returns to exhaust step 13; if so, the current time Tv of the first mode has reached the first mode sub-threshold, and the pump is controlled to enter exit step 22, or in some other embodiments, the pump that is prohibited from continuing to operate in the first mode is controlled to enter the normal dry run protection step 30. At this time, if the pump is not replaced and enters the normal dry run protection mode with less wear, it attempts to resume operation under better protection, which can maximize the pump's performance.

[0028] In exit step 22, the control pump 800 exits the first mode step. For example, the operation of pump 800 is stopped, and if the total dry running time is not saved, it is saved in permanent memory. In some embodiments, exit step 22 includes disabling the first mode step and continuing operation in other ways. This disabling is beneficial for pump protection, effectively preventing prolonged operation without coolant. This disabling is one-time, and is lifted when the pump is powered back on, allowing the first mode step. The first mode sub-threshold is greater than 5 minutes and not more than 30 minutes. For example, the first mode sub-threshold is 6 minutes, 11 minutes, 13 minutes, 15 minutes, 16 minutes, 18 minutes, 20 minutes, 24 minutes, or 28 minutes. In some embodiments, the first speed V1 is greater than the rest speed. The first speed V1 is not greater than 70% of the pump's rated speed, and the first speed V1 is not less than 3000 rpm. For example, the first speed V1 is 60%, 50%, 45%, or 35% of the pump's rated speed. In some specific implementations, the first speed V1 is 3200 rpm, 3500 rpm, 3800 rpm, or 4800 rpm.

[0029] The operating time-speed relationship curve of pump 800 is as follows: Figure 3 As shown.

[0030] In some pump usage scenarios, the cooling system (not shown) where pump 800 is installed is already filled with coolant, but the coolant has not yet entered pump 800. In the normal dry-run protection mode, it is difficult to generate an effective negative pressure in the cooling system, thus preventing coolant from being introduced into the pump. This is especially problematic when installing a new pump into a cooling system, as the pump is empty. If the pump cannot be filled with coolant quickly, the installation period for the new pump will be extremely long.

[0031] The first mode step is disabled when the total dry run time is not less than the total dry run threshold. This disabling of the first mode step is permanent. For example, this state of disabling the first mode step is stored in permanent memory, and this saved state is read back to controller 82 after the pump is powered on again. The total dry run threshold is greater than 60 minutes. In some specific embodiments, the total dry run threshold is calibrated experimentally. For example, the total dry run threshold is 100 minutes, 150 minutes, 160 minutes, 180 minutes, 250 minutes, 350 minutes, 400 minutes, 450 minutes, 600 minutes, 700 minutes, or 800 minutes.

[0032] Figure 4This diagram illustrates the pump's time-speed relationship when the pump is controlled according to a standard dry-run protection procedure, where the pump stops operating during rest periods. The standard dry-run protection procedure 30 includes controlling the pump to rest, and then attempting to restart the pump after the rest time threshold T1 has been reached. The pump attempt includes: controlling the pump to run at a test speed; if dry-running is detected to have disappeared, controlling the pump to run at the required speed; if dry-running is not detected after a predetermined test time threshold T2, the standard dry-run protection procedure 30 continues. Controlling the pump to rest includes controlling the pump to stop operating or controlling the pump to reduce its operating speed to a rest speed. The rest speed is less than a first speed V1. The first speed V1 is less than the test speed. For example, the pump's rated speed is 6,000 rpm, the test speed at 90% of the rated speed is 5.4,000 rpm, and the rest speed is 3,000 rpm. When the pump stops operating or operates at a low rest speed, the heat generated by the pump operating at the test speed or higher is reduced, the pump is relatively cooled, and excessive wear is effectively avoided. The rest time threshold is greater than 1 second. For example, the rest time threshold is 2 seconds, 5 seconds, 8 seconds, 10 seconds, 15 seconds, 20 seconds, 25 seconds, 30 seconds, 38 seconds, 45 seconds, or 50 seconds. The attempt operation time threshold is no greater than 5 seconds; for example, the attempt operation time threshold is 0.1 seconds, 0.2 seconds, 0.5 seconds, 1 second, or 2 seconds. In some specific implementations, under the normal dry-run protection mode, when the number of attempts by the control pump reaches the attempt count threshold, the control pump stops operating. The attempt count threshold is no less than 2 and no greater than 800. For example, the attempt count threshold is 6, 8, 10, 20, 80, 160, 300, 500, or 700.

[0033] While operating the pump in the first mode improves the efficiency of adding coolant to an empty system while taking into account pump wear, it is understandable that dry running in the first mode can still cause some damage to the pump. This application creatively employs protection measures to prevent the pump from operating in the first mode without restriction. Firstly, it limits the duration of each first-mode operation, specifically limiting the time Tv of that first-mode session to no more than a first-mode sub-threshold. This first-mode sub-threshold is a predetermined time value, preventing erroneous prolonged operation in the first mode. Secondly, it accumulates the total dry running time over the pump's entire lifespan. For example, the total dry running time is stored in the pump's control system memory. The total dry running time stored in memory is not lost due to power outages and typically only increases with accumulation, never decreasing. When the total dry running time is not less than the total dry running threshold, it indicates that the pump wear has reached its permissible limit, and continued operation in the first mode is likely to lead to failure. Therefore, continued operation in the first mode is prohibited to prevent excessive pump wear, thereby maximizing the pump's service potential and preventing accidental excessive damage to the cooling system due to pump failure.

[0034] 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: When dry running is detected, the pump is controlled to perform a first mode step. The first mode step includes controlling the pump to run at a first speed, accumulating the pump running time as the first mode current time, and controlling the pump to exit the first mode step when the first mode current time reaches a first mode threshold. The first mode threshold is greater than 5 minutes but not greater than 30 minutes, the first speed is not greater than 70% of the pump's rated speed, and the first speed is not less than 3000 rpm.

2. The method according to claim 1, wherein, The first mode steps include: Controlling the pump to exit the first mode step while simultaneously disabling the first mode step; and / or The total dry running time of the pump throughout its entire lifespan is defined as the total dry running time. The first mode step is disabled when the total dry running time is not less than a total dry running threshold, where the total dry running threshold is greater than 60 minutes, the first speed is not greater than 60% of the pump's rated speed, and the first speed is not less than 3800 rpm; and / or When dry running is detected to have disappeared, the control pump operates at the required speed.

3. The method according to claim 2, wherein, If dry running is detected and the first mode step is disabled, then the pump is controlled to perform a normal dry running protection step. The normal dry running protection step includes controlling the pump to rest for a rest time threshold and then controlling the pump to attempt to run. The pump attempt to run includes: The pump is controlled to operate at a trial speed greater than the first speed. If the dry running is detected to disappear, the pump is controlled to operate at the required speed. If the dry running is not detected to disappear after a predetermined trial operation time threshold, the pump is controlled to continue the conventional dry running protection steps. The rest time threshold is greater than 1 second, and the attempt operation time threshold is not greater than 5 seconds.

4. The method according to claim 3, wherein, The total dry-run threshold is greater than 100 minutes and not greater than 800 minutes. The first mode threshold is greater than 6 minutes and not greater than 28 minutes. In the normal dry-run protection mode, the rest time threshold is greater than 2 seconds, the attempt operation time threshold is not greater than 2 seconds, and when the number of attempts to run the pump reaches the attempt number threshold, the pump is controlled to stop running. The attempt number threshold is not less than 2.

5. The method according to claim 4, wherein, The total dry-run threshold is greater than 150 minutes and not greater than 450 minutes, the first mode threshold is greater than 10 minutes and not greater than 18 minutes, and the number of attempts threshold is not less than 6.

6. The method according to claim 4, wherein, The total dry-run threshold is greater than 160 minutes and not greater than 350 minutes, the first mode threshold is greater than 11 minutes and not greater than 16 minutes, and the number of attempts threshold is not less than 10.

7. The method according to claim 2, wherein, The total dry-run threshold is greater than 180 minutes and not greater than 250 minutes, the first mode threshold is greater than 13 minutes and not greater than 15 minutes, and the number of attempts threshold is not greater than 800.

8. The method according to claim 3, wherein, The detection of dry running includes detecting that the pump current is less than a current threshold, and the control of the pump to rest includes controlling the pump to stop operating or controlling the pump to reduce its operating speed to a rest speed, wherein the rest speed is less than the first speed.

9. The method according to claim 8, wherein, The current threshold is related to the pump speed; the lower the pump speed, the lower the current threshold.

10. A 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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