Cooling system

Abstract

To properly cool a componentry although abnormality occurs in a pump.SOLUTION: A cooling system 100 comprises: a coolant fluid circuit 3 in which coolant fluid flows, which therefore cools a battery pack 901 and a PCU 902; and an ECU 4 controlling the coolant fluid circuit 3. The coolant fluid circuit 3 includes: a first route 51; a second route 52; and a selector valve 9 switching between connection and disconnection of the first route 51 and the second route 52. The first route 51 includes a first water pump 81, and cools the battery pack 901. The second route 62 includes a second water pump 82, and cools the PCU 902. The ECU 4 controls the selector valve 9 in such a manner that the first route 51 and the second route 52 are disconnected from each other, when abnormality occurs in either the first water pump 81 or the second water pump 82 in a state in which the first route 51 and the second route 52 are connected to each other.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present disclosure relates to a cooling system, and more particularly to a cooling system using a coolant.

Background Art

[0002] The battery cooling system disclosed in Japanese Patent Application Laid-Open No. 2022-156950 (Patent Document 1) includes two pumps for circulating a coolant and a switching valve. The battery cooling system is configured such that the switching valve can switch which of the first to fifth paths the coolant flows through.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In a circuit configuration including two pumps as in Patent Document 1, an abnormality may occur in either one of the pumps. Then, the pump stopped due to the abnormality becomes a resistance, and the flow rate of the coolant decreases, and there is a possibility that the flow rate required for cooling the component to be cooled cannot be ensured. In that the occurrence of such a pump abnormality is not considered, there is room for improvement in the invention described in Patent Document 1.

[0005] The present disclosure has been made to solve the above problems, and one of the objects of the present disclosure is to appropriately cool components even when an abnormality occurs in a pump.

Means for Solving the Problems

[0006] A cooling system according to an aspect of the present disclosure is installed in a vehicle equipped with a battery pack and a drive device. The cooling system includes a coolant circuit that cools the battery pack and the drive device by circulating coolant, and a control device that controls the coolant circuit. The coolant circuit includes a first path, a second path, and a switching valve that switches between connecting and disconnecting the first path and the second path. The first path includes a first pump and cools the battery pack. The second path includes a second pump and cools the drive device. When an abnormality occurs in one of the first pump and the second pump in a situation where the first path and the second path are connected, the control device controls the switching valve so that the first path and the second path are separated.

[0007] In the above configuration, when an abnormality occurs in one of the first pump and the second pump in a situation where the first path and the second path are connected, the first path and the second path are separated. As a result, for the path that does not include the pump in which the abnormality has occurred among the first path and the second path, the circulation of the coolant can be continued using the normal pump. Since the path does not include the pump in which the abnormality has occurred, it is possible to prevent the pump in which the abnormality has occurred from acting as a resistance and reducing the flow rate of the coolant. Therefore, according to the above configuration, even when an abnormality occurs in the pump, the components can be appropriately cooled.

Effects of the Invention

[0008] According to the present disclosure, even when an abnormality occurs in the pump, the components can be appropriately cooled.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Modes for Carrying Out the Invention

[0010] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are denoted by the same reference numerals, and the description thereof will not be repeated.

[0011] [Embodiment] The "cooling system" according to the present disclosure is mounted on a vehicle.

[0012] [System Configuration] FIG. 1 is a diagram showing the overall configuration of a vehicle. The vehicle 900 is typically a battery electric vehicle (BEV), and includes a battery pack 901, a power control unit (PCU) 902 that is a driving device of the vehicle 900, and a charging device 903 configured to charge the battery pack 901 with external supply power.

[0013] The cooling system 100 includes a refrigerant circuit 1, a chiller 2, a coolant circuit 3, and an electronic control unit (ECU) 4.

[0014] The refrigerant circuit 1 is configured to adjust the temperature of the refrigerant circulating in the refrigerant circuit 1. The refrigerant circuit 1 has, for example, a configuration equivalent to a general heat pump system, and includes a compressor 11, a condenser 12, expansion valves 13 and 14, and an evaporator 15.

[0015] The chiller 2 performs heat exchange between the refrigerant circulating in the refrigerant circuit 1 and the coolant circulating in the coolant circuit 3. More specifically, the liquid-phase refrigerant depressurized by the expansion valve 14 evaporates in the chiller 2, thereby taking heat from the coolant circulating in the coolant circuit 3. As a result, the coolant circulating in the coolant circuit 3 is cooled.

[0016] The coolant circuit 3 includes a cooling path 5, a radiator 6, a reserve tank (R / T) 7, a first water pump (W / P) 81, a second water pump 82, and a switching valve 9. Although not shown, the radiator 6 is provided with a radiator fan.

[0017] The cooling path 5 is a pipe that constitutes the flow path of the coolant. The coolant is, for example, LLC (Long Life Coolant) containing ethylene glycol or the like. The cooling path 5 includes a first path 51 and a second path 52.

[0018] The first path 51 includes a path 51A and a path 51B. The path 51A connects between the switching valve 9 and the reserve tank 7. A battery pack 901 is connected to the path 51A. The path 51B connects between the reserve tank 7 and the switching valve 9. A first water pump 81 and a chiller 2 are connected to the path 51B. The path 51A and the path 51B are connected within the reserve tank 7.

[0019] The second path 52 includes a path 52A, a path 52B, and a path 52C. The path 52A connects between the switching valve 9 and the reserve tank 7. A radiator 6 is connected to the path 52A. The path 52B connects between the switching valve 9 and the reserve tank 7. No devices such as the radiator 6 are connected to the path 52B, and it is configured to bypass the radiator 6. The path 52A and the path 52B are connected within the reserve tank 7. The path 52C connects between the path 52B at the upstream (front) of the connection point to the reserve tank 7 and the switching valve 9. A first water pump 81, a PCU 902, and a charging device 903 are connected to the path 52C.

[0020] The first water pump 81 is an electric water pump that discharges the coolant according to a control command from the ECU 4. The path 51A is connected upstream of the path 51B to which the first water pump 81 is connected. By driving the first water pump 81, the battery pack 901 provided in the path 51A can be cooled. The first water pump 81 corresponds to the "first pump" according to the present disclosure.

[0021] The second water pump 82 is an electric water pump that discharges the coolant according to a control command from the ECU 4. Downstream of the first water pump 81 in the path 52C, the PCU 902 is connected. The coolant discharged from the first water pump 81 can cool the PCU 902 and the charging device 903. The second water pump 82 corresponds to the "second pump" according to the present disclosure.

[0022] The switching valve 9 is a five-way valve in this example. The switching valve 9 is configured to be able to switch the cooling path 5 according to a control command from the ECU 4 so that the coolant input to at least one of the path 51B and the path 52C is output from at least one of the path 51A, the path 52A, and the path 52B. The switching control of the switching valve 9 will be described with reference to FIG. 2.

[0023] The ECU 4 controls the first water pump 81, the second water pump 82, and the switching valve 9 based on the temperature of the coolant detected by a plurality of temperature sensors (not shown) provided in the battery pack 901, the PCU 902, the charging device 903, and the coolant circuit 3, respectively.

[0024] <Switching of the coolant circuit> FIG. 2 is a schematic diagram for explaining the switching of the coolant circuit 3. The coolant circuit 3 is configured to switch between a "series path" and an "independent path" by controlling the switching valve 9 according to a control command from the ECU 4.

[0025] The series path is a path in which the first path 51 and the second path 52 are connected in series. In the example shown in FIG. 2, the switching valve 9 is controlled such that the path 51B in the first path 51 and the path 52A in the second path 52 are connected, and the path 51A in the first path 51 and the path 52C in the second path 52 are connected. Although not shown, the path 51B and the path 52B may be connected. In the series path, since the coolant flows through the entire first path 51 and the second path 52, two water pumps exist on the path.

[0026] An independent path means that the first path 51 and the second path 52 are separated, in other words, paths independent of each other. In the example shown in FIG. 2, the switching valve 9 is controlled such that the path 51A and the path 51B in the first path 51 are connected, and the path 52A and the path 52C in the second path 52 are connected. Although not shown, the path 52B and the path 52C may be connected. In an independent path, the coolant flows separately through the first path 51 and the second path 52. In this case, there is one water pump on each path.

[0027] In the coolant circuit 3 configured as described above, an abnormality may occur and one of the first water pump 81 and the second water pump 82 may stop. When an abnormality of the water pump occurs under the situation of the series path, the stopped water pump becomes a resistance and the flow rate of the coolant decreases, and there is a possibility that the flow rate required for cooling the components to be cooled (the battery pack 901, the PCU 902, and the charging device 903) cannot be ensured.

[0028] Therefore, in the present embodiment, when an abnormality occurs in one of the water pumps under the situation where the coolant circuit 3 is a series path, the ECU 4 controls the switching valve 9 so that the coolant circuit 3 can be switched from the series path to an independent path (that is, the first path 51 and the second path 52 are separated). As a result, for the paths including the normal water pump among the first path 51 and the second path 52, it becomes possible to ensure the flow rate required for cooling the components. Specifically, when the coolant circuit 3 is switched when an abnormality occurs in the first water pump 81, the PCU 202 and the charging device 903 provided in the second path 52 can be appropriately cooled by the normal second water pump 82 without being affected by the increase in resistance of the first water pump 81. Conversely, when the coolant circuit 3 is switched when an abnormality occurs in the second water pump 82, the battery pack 901 provided in the first path 51 can be appropriately cooled by the normal first water pump 81 without being affected by the increase in resistance of the second water pump 82.

[0029] <Processing Flow of Switching Control> FIG. 3 is a flowchart showing an example of the control processing procedure in the cooling system 100. The processing shown in this flowchart is called from the main routine and executed when a predetermined condition is satisfied (for example, at each predetermined cycle) during the operation of the cooling system 100. Hereinafter, the case where an abnormality occurs in the second water pump 82 will be typically described, but the same control can be executed when an abnormality occurs in the first water pump 81.

[0030] In S1, the ECU 4 determines whether the coolant circuit 3 is a series path. If the coolant circuit 3 is an independent path (NO in S1), the ECU 4 returns the process to the main routine. If the coolant circuit 3 is a series path (YES in S1), the ECU 4 advances the process to S2.

[0031] In S2, the ECU 4 determines whether the rotational speed N2 of the second water pump 82 is less than the threshold value TH. The threshold value TH is a low rotational speed at which an abnormality may occur in the second water pump 82 and is predetermined. If the rotational speed N2 of the second water pump 82 is equal to or higher than the threshold value TH (NO in S2), the ECU 4 returns the process to the main routine. If the rotational speed N2 of the second water pump 82 is less than the threshold value TH (YES in S2), the ECU 4 advances the process to S3.

[0032] In S3, the ECU 4 determines whether the elapsed time ΔT in the state where the rotational speed N2 of the second water pump 82 is less than the threshold value TH has reached the first reference time REF1. The first reference time REF1 is the longest time for the self-protection function of the second water pump 82 (the function of automatically reducing the rotational speed N2 to protect itself from failure) to be exerted and is predetermined according to the specifications of the second water pump 82. If the elapsed time ΔT is less than the first reference time REF1 (NO in S3), the ECU 4 waits. When the elapsed time ΔT reaches the first reference time REF1 (YES in S3), the ECU 4 advances the process to S4.

[0033] In S4, the ECU 4 determines that there may be an abnormality in the second water pump 82. Then, the ECU 4 controls the switching valve 9 so that the coolant circuit 3 can be switched from the series path to the independent path.

[0034] In S5, the ECU 4 improves the output (coolant discharge amount or rotational speed) of the first water pump 81 compared to before the switching to the independent path of the coolant circuit 3. As one specific example, when the first water pump 81 is controlled in three steps of low output, medium output, and high output, the ECU 4 improves the output of the first water pump 81 to one step higher (for example, high output) than the output (for example, medium output) determined according to the coolant temperature in the series path.

[0035] In S6, the ECU 4 improves the output (rotational speed) of the radiator fan compared to before the switching to the independent path of the coolant circuit 3. This process can also be realized in the same way as the process in S5.

[0036] In S7, the ECU 4 determines whether the elapsed time ΔT in the state where the rotational speed N2 of the second water pump 82 is less than the threshold value TH is longer than the second reference time REF2. The second reference time REF2 is a time longer than the first reference time REF1 in S3 and is predetermined to start subsequent retry control. Until the elapsed time ΔT reaches the second reference time REF2 (NO in S7), the ECU 4 waits. When the elapsed time ΔT reaches the second reference time REF2 (YES in S7), the ECU 4 proceeds with the process to S8.

[0037] In S8, the ECU 4 executes retry control. When the rotational speed N2 of the second water pump 82 is less than the threshold value TH, in addition to the possibility that an abnormality has occurred in the second water pump 82, there is also a possibility that the second water pump 82 is simply out of tune. Retry control is control to restart the second water pump 82 after once stopping the second water pump 82.

[0038] In S9, the ECU 4 determines whether the rotational speed N2 of the second water pump 82 has increased above the threshold value TH by retry control. When the rotational speed N2 of the second water pump 82 is equal to or higher than the threshold value TH (YES in S9), the second water pump 82 is likely to have returned to a normal state by retry control even though the rotational speed N2 has decreased due to out-of-synchronization. Therefore, the ECU 4 controls the switching valve 9 so that the coolant circuit 3 is switched from the independent path to the series path (S12). Also, the ECU 4 decreases the output of the first water pump 81, which was improved in S5, to the value before the improvement (S13). Further, the ECU 4 decreases the output of the radiator fan, which was improved in S6, to the value before the improvement (S14).

[0039] On the other hand, when the rotational speed N2 of the second water pump 82 is less than the threshold value TH even after executing the retry control (NO in S9), the ECU 4 advances the process to S10 and determines whether the elapsed time ΔT in the state where the rotational speed N2 of the second water pump 82 is less than the threshold value TH is longer than the third reference time REF3. The third reference time REF3 is a time longer than the second reference time REF2 in S7 and is determined in advance to determine whether the second water pump 82 can return from out-of-synchronization by retry control. When the elapsed time ΔT is less than the third reference time REF3 (NO in S10), the ECU 4 returns the process to S9. When the elapsed time ΔT reaches the third reference time REF3 (YES in S10), the ECU 4 advances the process to S11.

[0040] In S11, the ECU 4 confirms the diagnosis that an abnormality has occurred in the second water pump 82 and records the diagnosis result in the diagnosis.

[0041] As described above, in the present embodiment, the coolant circuit 3 is a series path, and when an abnormality (there is a possibility thereof) occurs in one of the first water pump 81 and the second water pump 82, the ECU 4 switches the coolant circuit 3 from the series path to an independent path. Thereby, for the path that does not include the water pump in which an abnormality has occurred among the first path 51 and the second path 52, the circulation of the coolant can be continued using the normal water pump. Since the path does not include the pump in which an abnormality has occurred, it is possible to prevent the pump in which an abnormality has occurred from acting as a resistance and reducing the flow rate of the coolant. Therefore, according to the present embodiment, even when an abnormality occurs in one of the first water pump 81 and the second water pump 82, the component to be cooled can be appropriately cooled.

[0042] The embodiments disclosed this time should be considered to be illustrative in all respects and not restrictive. The scope of the present disclosure is shown not by the description of the above-described embodiments but by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims.

Explanation of Reference Numerals

[0043] 100 Cooling system, 1 Refrigerant circuit, 11 Compressor, 12 Condenser, 13, 14 Expansion valve, 15 Evaporator, 2 Chiller, 3 Coolant circuit, 4 ECU, 5 Cooling path, 51 First path, 51A, 51B Paths, 52 Second path, 52A, 52B, 52C Paths, 6 Radiator, 7 Reservoir tank, 81 First water pump, 82 Second water pump, 9 Switching valve, 900 Vehicle, 901 Battery pack, 902 PCU, 903 Charging device.

Claims

【Claim 1】 A cooling system installed in a vehicle equipped with a battery pack and a drive device, comprising: a coolant circuit that cools the battery pack and the drive device by circulating coolant; and a control device that controls the coolant circuit, wherein the coolant circuit includes a first pump and a first path for cooling the battery pack; includes a second pump and a second path for cooling the drive device; and includes a switching valve for switching connection and separation between the first path and the second path, and the control device controls the switching valve so that the first path and the second path are separated when an abnormality occurs in one of the first pump and the second pump in a situation where the first path and the second path are connected.

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