cooling system

Abstract

Provided is a cooling system capable of notifying of replacement of coolant due to mixing of water at an appropriate timing. The cooling system includes a coolant reservoir that stores coolant; a circulation pump that circulates the coolant stored in the coolant reservoir; a conductivity measurement sensor that is disposed at a bottom portion of the coolant reservoir and measures conductivity of the coolant stored in the coolant reservoir; a control device that controls start and stop of the circulation pump and causes the conductivity measurement sensor to measure the conductivity, and determines whether a measured value of the conductivity is equal to or greater than a threshold value set in advance; and a notification device that notifies of replacement of the coolant when the control device determines that the threshold value is exceeded. The control device causes the conductivity measurement sensor to measure the conductivity when a set time set in advance elapses after the circulation pump is stopped.

Description

Technical Field

[0001] The present invention relates to a cooling system having a circulation path for circulating a coolant containing a non-aqueous base agent. Background Technology

[0002] As an example of this technology, a cooling system is disclosed in Patent Document 1. The cooling system includes: a circulation path for circulating a coolant containing a non-aqueous base agent; and a reservoir disposed on the circulation path for storing the coolant. The coolant is a liquid containing a non-aqueous base agent, and therefore is an insulating coolant. Therefore, this cooling system is used, for example, for cooling electronic equipment and electronic components in electric vehicles.

[0003] However, in the coolant reservoir or circulation path, water may sometimes mix into the coolant due to accidental injection or condensation, increasing the coolant's conductivity. Therefore, the cooling system includes a conductivity sensor in the reservoir to measure the coolant's conductivity. The cooling system's control device then determines whether the conductivity sensor's reading is above a preset threshold. If the reading is above the threshold, a notification device can be activated to request a coolant replacement.

[0004] Patent Document 1: Japanese Patent Application Publication No. 2022-158432 Summary of the Invention

[0005] However, the cooling system includes a circulation pump that circulates the coolant stored in the reservoir through a circulation path. When the circulation pump is operating, the water contained in the coolant is agitated along with the non-aqueous base agent within the pump. Consequently, even when the coolant should be replaced due to water contamination, the coolant reading measured by the conductivity sensor may sometimes be below the replacement threshold. As a result, coolant replacement may not be notified at the appropriate time.

[0006] The present invention has been made in view of this aspect, and its object is to provide a cooling system that can notify the replacement of coolant at the appropriate time when the coolant is mixed with water.

[0007] In view of the aforementioned issues, the cooling system of the present invention is a cooling system having a circulation path for circulating a coolant containing a non-aqueous base agent. The cooling system includes at least: a reservoir disposed in the circulation path and storing the coolant; a circulation pump that circulates the coolant stored in the reservoir in the circulation path; a conductivity sensor disposed at the bottom of the reservoir and measuring the conductivity of the coolant stored in the reservoir; a control device that controls the starting and stopping of the circulation pump, and causes the conductivity sensor to measure the conductivity, and determines whether the measured value of the conductivity measured by the conductivity sensor is above a preset threshold; and a notification device that, when the control device determines that the conductivity is above the threshold, notifies the replacement of the coolant, wherein the control device causes the conductivity sensor to measure the conductivity after a preset time has elapsed since the circulation pump was stopped.

[0008] In a preferred embodiment, if the control device stops the circulation pump but starts the circulation pump before the set time has elapsed, it starts the circulation pump after measuring the conductivity using the conductivity measuring sensor.

[0009] Invention Effects

[0010] According to the present invention, it is possible to notify the replacement of coolant at an appropriate time when the coolant is contaminated with moisture. Attached Figure Description

[0011] Figure 1 This is a diagram illustrating the device structure of the cooling system according to an embodiment of the present invention.

[0012] Figure 2 yes Figure 1 The control block diagram of the cooling system control device is shown.

[0013] Figure 3 It means Figure 1 The graph shows the relationship between the conductivity of the coolant in the cooling system and time.

[0014] Figure 4 yes Figure 2 The control flowchart of the control device is shown. Detailed Implementation

[0015] The following is for reference. Figures 1-4 The cooling system 1 involved in this embodiment will be described. Figure 1 This is a diagram illustrating the device structure of the cooling system 1 according to an embodiment of the present invention. The cooling system 1 according to this embodiment is, for example, a cooling system installed in an electric vehicle. Figure 1As shown, the cooling system 1 is a system for cooling on-board equipment such as the battery 52 installed in the electric vehicle.

[0016] Specifically, the cooling system 1 has a circulation path 50 formed by piping and the like, which circulates the coolant. The cooling system 1 includes: a reservoir 20 disposed on the circulation path 50 and storing coolant C; and a circulation pump 30 that circulates the coolant C stored in the reservoir 20 on the circulation path 50.

[0017] The circulation pump 30 includes a pump body 31 disposed in the circulation path 50 and a motor 32 that operates the pump body 31. The motor 32 is driven by a control signal from the control device 10 (described later), and the pump body 31 operates due to the torque of the motor 32. This allows the coolant C in the storage tank 20 to circulate in the circulation path 50. In this embodiment, as an example, a refrigerator 51, a battery 52, an oil cooler 53, an inverter 54, a drive motor 55, a radiator 56, etc., are connected in series in the circulation path 50.

[0018] In this embodiment, the coolant (composition) C contains a non-aqueous base agent, specifically, an insulating base agent as a non-aqueous base agent. The coolant C is electrically insulating and has a conductivity lower than that of water. That is, the insulating base agent is, for example, an insulating oil, preferably a hydrocarbon oil, an ester oil, or a mixture thereof. Examples of hydrocarbon oils include mineral oil, synthetic hydrocarbon oils, or mixtures thereof. Examples of mineral oils include paraffinic mineral oil, naphthenic mineral oil, or mixtures thereof. The content of the insulating base agent in the coolant composition is, for example, 10 to 100% by mass, preferably 30 to 99% by mass, more preferably 50 to 99% by mass, and even more preferably 70 to 99% by mass.

[0019] Coolant C may also contain insulating additives such as flame retardants, antioxidants, rust inhibitors, friction modifiers, corrosion inhibitors, viscosity index improvers, pour point depressants, dispersants, surfactants, wear-resistant agents, or solid lubricants. The content of additives in coolant C is, for example, 0.1–20% by mass, preferably 0.2–10% by mass, more preferably 0.4–5% by mass, and even more preferably 0.5–1% by mass.

[0020] The refrigeration unit 51 is a heat exchange device that uses coolant C as a refrigerant to absorb heat from coolant C and cool it. Downstream of the refrigeration unit 51 in the circulation path 50, a battery 52, an oil cooler 53, an inverter 54, a drive motor 55, and a radiator 56 are connected in sequence.

[0021] Battery 52 is a secondary battery that supplies power to the drive motor 55 and the like via inverter 54 (described later). Furthermore, oil cooler 53 is a cooling device that cools the oil by exchanging heat between the oil and coolant C supplied to the powertrain of the vehicle, including the drive motor 55 and the like. Radiator 56 is located at the front of the vehicle and cools the coolant C flowing inside it by exchanging heat with the outside air.

[0022] In this embodiment, coolant C is stored in the storage tank 20, and coolant C is discharged from the bottom 21 of the storage tank 20 via the circulation pump 30. The coolant C discharged by the circulation pump 30 passes sequentially through the refrigerator 51, battery 52, oil cooler 53, inverter 54, drive motor 55, and radiator 56 connected to the circulation path 50, and returns to the storage tank 20 from the top. Thus, the coolant C can be used to cool the various devices while circulating in the circulation path 50.

[0023] In this embodiment, the cooling system 1 includes: a conductivity sensor 40 for measuring the conductivity of the coolant C stored in the reservoir 20; and a temperature sensor 60 for detecting the temperature of the coolant C. The conductivity sensor 40 is electrically connected to the control device 10. The conductivity sensor 40 intermittently measures the conductivity of the coolant C using a control signal from the control device 10.

[0024] The water (moisture) mixed into the coolant C has a higher specific gravity and higher conductivity than the non-aqueous base agent (insulating oil) contained in the coolant C. When water is mixed into the coolant C, the water in the coolant C tends to accumulate at the bottom 21 of the reservoir 20. From this point of view, in this embodiment, the conductivity measuring sensor 40 is disposed at the bottom 21 of the reservoir 20.

[0025] Therefore, it is possible to measure the conductivity of a portion of the coolant C stored in the reservoir 20 that contains a relatively large amount of water. The conductivity value of the coolant C measured by the conductivity sensor 40 is output to the control device 10.

[0026] Temperature sensor 60 is electrically connected to control device 10. Its placement is not particularly limited as long as it can detect the temperature of the coolant C flowing between radiator 56 and circulation pump 30. In this embodiment, temperature sensor 60 is disposed inside (upper part) of reservoir 20 to detect the temperature of the coolant C stored in reservoir 20. The detected temperature value of coolant C by temperature sensor 60 is output as temperature data to control device 10.

[0027] The notification device 70 is electrically connected to the control device 10 and is a device that notifies the replacement of coolant C when moisture has mixed in with it. The notification device 70 can be a warning light that urges the replacement of coolant C; the notification method is not limited as long as it can urge the replacement of coolant C. The conditions for notification by the notification device 70 will be described together with the description of the control device 10.

[0028] Although not shown in the figure, the control device 10 is a microcomputer consisting of an arithmetic unit (CPU) for performing operations, a secondary storage device (ROM) that records the program used for operations, and a temporary storage device (RAM) that stores the operation process or temporary control variables.

[0029] Specifically, the control device 10 controls the starting and stopping of the circulation pump 30 (specifically, the motor 32). Furthermore, the control device 10 causes the conductivity measuring sensor 40 to measure conductivity and determines whether liquid replacement is required based on whether the measured conductivity value is above a preset threshold. A secondary storage device stores a program for controlling the circulation pump 30 and determining liquid replacement, which is executed by the computing device. The conductivity values ​​obtained during program execution are temporarily stored in the aforementioned temporary storage device.

[0030] Figure 2 yes Figure 1 The control block diagram of the control device 10 for the cooling system 1 is shown. Figure 2 As shown, the control device 10, as software, includes a pump operation determination unit 11, a pump operation execution unit 12, a stop time measurement unit 13, a measurement determination unit 14, a measurement execution unit 15, a liquid replacement determination unit 16, and a notification execution unit 17.

[0031] The pump operation determination unit 11 determines whether to start and stop the circulation pump 30 based on factors such as the vehicle's driving conditions. For example, the pump operation determination unit 11 determines whether to start and stop the circulation pump 30 based on factors such as the temperature of the battery 52 or other equipment, or the torque and driving time generated by the drive motor 55.

[0032] The pump operation execution unit 12 executes the start or stop of the motor 32 of the circulating pump 30 based on the determination result of the pump operation determination unit 11. Specifically, the pump operation execution unit 12 controls the operation of the circulating pump 30, including starting and stopping the circulating pump 30, by sending a control signal to the circulating pump 30 (motor 32).

[0033] The stop time measuring unit 13 measures the stop time after the circulating pump 30 stops. Specifically, the stop time measuring unit 13 measures the elapsed time after the pump operation execution unit 12 sends a control signal to the circulating pump 30 to stop the operation, and uses this time as the stop time.

[0034] The measurement determination unit 14 determines whether to allow the conductivity measuring sensor 40 to measure the conductivity of the coolant C. Specifically, the measurement determination unit 14 determines whether a preset time has elapsed after the circulation pump 30 has stopped, based on the stop time measured by the stop time measuring unit 13, as a condition for measurement execution, and whether this condition is met. Furthermore, the measurement determination unit 14 determines whether the condition for measurement execution is met by setting the time between the stop time and the start of the circulation pump 30 before the aforementioned preset time has elapsed. Moreover, the following can also be performed... Figure 4 The determination condition for the measurement execution in step S306.

[0035] Additionally, the “set time” mentioned here refers to the time after the circulation pump 30 stops, during which the water in the coolant C containing water is separated from the non-aqueous base agent by the above-mentioned specific gravity and accumulates at the bottom 21 of the storage tank 20, for example, set to about 10 minutes.

[0036] The measurement execution unit 15 measures the conductivity of the coolant C using the conductivity measuring sensor 40 based on the determination result of the measurement determination unit 14. Specifically, when the determination conditions for measurement execution are met, the measurement execution unit 15 intermittently sends control signals to the conductivity measuring sensor 40 to measure the conductivity of the coolant C, thereby executing the measurement control of the conductivity measuring sensor 40.

[0037] The liquid replacement determination unit 16 determines whether the conductivity measured by the conductivity measuring sensor 40 in the measurement execution unit 15 is above a preset threshold. Specifically, such as... Figure 3 As shown, when the cooling system 1 is used appropriately, as indicated by the solid line L1, the conductivity of the coolant C only increases slightly even after time. Therefore, in this case, specifically, the fluid replacement determination unit 16 determines not to perform a replacement of the coolant C.

[0038] However, for example, if unexpected moisture is introduced into the coolant C due to condensation in the circulation path 50 or the reservoir 20, or due to the absorption of moisture by the coolant C, the conductivity becomes as shown by the dashed line L3. In this dashed line L3, the conductivity of the coolant C containing moisture increases at a higher rate than the solid line L1, and at time T1, the measured value reaches the threshold P1 (e.g., conductivity 0.1 μS / cm). Moreover, if water is accidentally injected at time T2, as shown by the double-dotted line L2, the conductivity of the coolant C containing water increases sharply, and at time T3, the measured value reaches the threshold P1 (e.g., conductivity 0.1 μS / cm). In these cases, the liquid replacement determination unit 16 determines that the coolant C should be replaced and notifies the execution unit 17 to have the notification device 70 execute the notification.

[0039] The following is for reference. Figure 4 , based on Figure 2 The control flow of the control device 10 shown will be explained. Figure 4 yes Figure 2 The control flowchart of the control device 10 is shown. First, in the execution... Figure 4 Prior to the control flow shown, the pump operation determination unit 11 determines whether the circulating pump 30, which is currently in operation, should be stopped based on factors such as the vehicle's driving conditions. If it is determined that the circulating pump 30 should be stopped, the pump operation execution unit 12 stops the circulating pump 30. In this state, the process proceeds to step S301.

[0040] In step S301, the stop time measuring unit 13 measures the time (stop time) after the circulation pump 30 stops. Next, the process proceeds to step S302, where the measurement determination unit 14 determines whether the stop time has reached the set time. If the measurement determination unit 14 determines that the stop time has not reached the set time (NO), the process proceeds to step S303 because the measurement conditions for the coolant C based on the conductivity measurement sensor 40 are not met.

[0041] In step S303, the measurement determination unit 14 determines whether it is before the circulation pump 30 is started. Specifically, the measurement determination unit 14 uses the determination of whether the pump operation determination unit 11 determines that the circulation pump 30 is started (specifically, whether the pump operation execution unit 12 has sent a control signal to start the circulation pump 30) as the determination condition for measurement execution (measurement condition). Here, if it is determined that it is not before the control signal to start the circulation pump 30 is sent (NO), the process returns to step S301.

[0042] Thus, without sending a control signal to start the circulation pump 30, the process of steps S301 to S303 is repeated if the stop time of the circulation pump 30 has not reached the set time. Then, in step S302, if the measurement determination unit 14 determines that the stop time has reached the set time (YES), since the measurement conditions of the coolant C based on the conductivity measurement sensor 40 are met, the process proceeds to step S304. In step S304, the measurement execution unit 15 intermittently sends control signals to the conductivity measurement sensor 40, causing the conductivity measurement sensor 40 to measure the conductivity of the coolant C, and the process proceeds to step S305.

[0043] In step S305, the liquid replacement determination unit 16 determines whether the conductivity measured by the conductivity measuring sensor 40 is above a preset threshold. If the conductivity of the coolant C is above the preset threshold (YES), the process proceeds to step S309. In step S309, the notification execution unit 17 sends a notification instruction (notification signal) to the notification device 70 to notify that the coolant C should be replaced, causing the notification device 70 to execute the notification.

[0044] Thus, while the circulation pump 30 is operating, the water contained in the coolant C is stirred together with the non-aqueous base agent of the coolant C within the circulation pump 30. However, in step S302, the coolant C can be left to stand in the reservoir 20 for a certain period of time (specifically, a set time). As a result, the water in the coolant C, which contains water, easily accumulates at the bottom 21 of the reservoir 20 due to separation from the non-aqueous base agent by specific gravity. Consequently, in order to detect whether the coolant C contains more water than expected, it is possible to determine whether the conductivity of the coolant C is above a threshold. Thus, the notification device 70 can notify the driver or others at an appropriate time that the coolant C needs to be replaced due to the presence of water.

[0045] Here, in step S305, if the conductivity measured by the conductivity measuring sensor 40 is less than a preset threshold (NO) due to the liquid replacement determination unit 16, the process proceeds to step S306. In step S306, the measurement determination unit 14 determines whether it is before the circulation pump 30 is started. Specifically, as described above, the measurement determination unit 14 determines whether the pump operation determination unit 11 determines that the circulation pump 30 is started (specifically, whether the pump operation execution unit 12 has sent a control signal to start the circulation pump 30) as the determination condition for measurement execution. Here, if it is determined that it is not before the control signal to start the circulation pump 30 is sent (NO), step S306 is repeated.

[0046] In steps S303 and S306, if the measurement determination unit 14 determines that a control signal to start the circulation pump 30 from the pump operation execution unit 12 is to be sent (YES), in order to satisfy the determination condition for measurement execution based on the conductivity measurement sensor 40, the process proceeds to step S307.

[0047] In step S307, the measurement execution unit 15 intermittently sends control signals to the conductivity measuring sensor 40, causing the conductivity measuring sensor 40 to measure the conductivity of the coolant C. Then, the pump operation execution unit 12 sends a control signal to start the circulation pump 30 (motor 32), starting the circulation pump 30 and proceeding to step S308.

[0048] In step S308, the liquid replacement determination unit 16 determines whether the conductivity measured by the conductivity measuring sensor 40 is above a preset threshold. If the conductivity of the coolant C is above the preset threshold (YES), the process proceeds to step S309. In step S309, the notification execution unit 17 sends a notification instruction (notification signal) to the notification device 70 to indicate that the coolant C should be replaced, causing the notification device 70 to execute the notification.

[0049] On the other hand, in step S308, if the conductivity measured by the conductivity measuring sensor 40 is less than a preset threshold (NO) by the liquid replacement determination unit 16, a series of processes will end until the circulation pump 30 is stopped again.

[0050] In this embodiment, after stopping the circulation pump 30 when proceeding from step S303 to step S307, the circulation pump 30 is restarted before a set time has elapsed. Even in this case, the determination condition for measuring the conductivity of the coolant C is met by the determination unit 14.

[0051] As a result, after the conductivity measuring sensor 40 measures the conductivity of the coolant C by the measuring execution unit 15, the circulation pump 30 can be started by the pump operation execution unit 12. Therefore, the conductivity of the coolant C can be measured before the water contained in the coolant C is stirred by the non-aqueous base agent. Furthermore, even if water has mixed into the coolant C during a long period of non-use of the circulation pump 30, the conductivity of the coolant C can be confirmed in step S307.

[0052] The embodiments of the present invention have been described in detail above, but the present invention is not limited to the described embodiments. Various design changes can be made without departing from the spirit of the present invention as set forth in the claims.

[0053] For example, in Figure 4 In step S307, the circulation pump 30 is started after the conductivity is measured and before proceeding to step S308. However, for example, in S307, the circulation pump 30 may not be started after the conductivity is measured, and step S308 may proceed only when the conductivity is less than a threshold. Thus, before starting the circulation pump 30, in step S309, a notification command for replacing the coolant C can be sent to the notification device 70, urging the driver or others to replace the coolant C.

[0054] Symbol Explanation

[0055] 1-Cooling system, 10-Control device, 20-Reservoir, 21-Bottom, 30-Circulation pump, 40-Conductivity measuring sensor, 50-Circulation path, 70-Notification device, C-Coolant.

Claims

1. A cooling system having a circulation path for circulating a coolant containing a non-aqueous base agent, The cooling system is characterized by having at least the following features: A storage tank, which is located in the circulation path and stores the coolant; A circulation pump that circulates the coolant stored in the reservoir in the circulation path; A conductivity sensor is disposed at the bottom of the liquid storage tank to measure the conductivity of the coolant stored in the liquid storage tank; A control device controls the start and stop of the circulating pump, and causes the conductivity measuring sensor to measure the conductivity, and determines whether the measured value of the conductivity measured by the conductivity measuring sensor is above a preset threshold. and The notification device notifies the control device to replace the coolant when the threshold value is determined to be above the threshold. After the control device stops the circulating pump, and a preset time has elapsed, the conductivity sensor measures the conductivity.

2. The cooling system according to claim 1, characterized in that, If the control device stops the circulation pump but starts the circulation pump before the set time has elapsed, it starts the circulation pump after measuring the conductivity using the conductivity measuring sensor.

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