Cooling system

Abstract

To secure cooling performance even when an abnormality occurs in an electric-type pump.SOLUTION: A cooling system 10, which cools a motor 11 of an electric vehicle and also makes a radiator 12 cool a cooling medium, comprises: cooling circuits 13 which have a main circuit in which an electric-type pump 14A circulates the cooling medium and a sub circuit in which a mechanical pump 14B circulates the cooling medium; a transmission device 16 that connects and disconnects transmission of power between the motor 11 and the mechanical pump 14B; a switching device 17 that switches between a first state where the cooling medium is circulated through the main circuit and a second state where the cooling medium is circulated through the sub circuit; sensing devices 18 and 19A that sense an abnormality of the electric-type pump; and a control device 19 that when the electric-type pump 14A is normal, sets the switching device 17 in the first state, and when the electric-type pump 14A is abnormal, makes the transmission device 16 connect the motor 11 to the mechanical pump 14B and sets the switching device 17 in the second state.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a cooling system that cools a drive motor of an electric vehicle with a cooling medium. [Background technology]

[0002] 2. Description of the Related Art Electric vehicles that run using a drive motor are known. Electric vehicles are generally equipped with a liquid-cooling type cooling device that cools a drive motor using a cooling circuit that circulates a cooling medium such as oil, cooling water, etc. For example, Patent Document 1 discloses a cooling device that cools an electric motor by circulating antifreeze as a cooling medium in a cooling circuit using an electric pump. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2004-75050 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the technology of Patent Document 1, the cooling medium is circulated by an electric pump, so in the unlikely event that a failure occurs in the electric circuit or the electric pump itself, the electric pump will not operate and the drive motor will not be cooled by the electric pump, which may cause the electric vehicle to become unable to run. Therefore, in the conventional technology, there is room for improvement in terms of ensuring cooling performance and enabling the electric vehicle to run even when the electric pump does not operate normally. The cooling system of the present invention has been devised in view of the above-mentioned problems, and one of its objectives is to ensure cooling performance and enable the electric vehicle to run even when the electric pump is not operating normally. [Means for solving the problem]

[0005] The present invention has been made to solve at least part of the above problems, and can be realized in the following aspects or application examples.

[0006] (1) This application example is a cooling system that cools a drive motor of an electric vehicle with a cooling medium and cools the cooling medium with a radiator, the cooling system including a main circuit that circulates the cooling medium between the radiator and the drive motor using an electric pump driven by electric power, and a sub-circuit that circulates the cooling medium between the radiator and the drive motor using a mechanical pump mechanically driven by the drive motor, a transmission device that connects the drive motor and the mechanical pump in a manner that allows power transmission to be disconnected, a switching device that is attached to the cooling circuit and switches between a first state in which the cooling medium is circulated through the main circuit and a second state in which the cooling medium is circulated through the sub-circuit, a detection device that detects an abnormality in the electric pump, and a control device that sets the switching device to the first state when no abnormality in the electric pump is detected by the detection device, and that connects the drive motor and the mechanical pump via the transmission device and sets the switching device to the second state when an abnormality in the electric pump is detected.

[0007] According to this, the cooling circuit of the cooling system is provided with a sub-circuit that uses a mechanical pump to circulate the cooling medium between the radiator and the drive motor, and if an abnormality is detected in the electric pump, the cooling medium can be circulated through the sub-circuit that uses the mechanical pump. Therefore, the circulation of the cooling medium can be continued even if the electric pump does not operate normally due to a failure of the electric circuit that supplies power to the electric pump, a failure of the electric pump body, etc. Therefore, even if the electric pump does not operate normally, the cooling performance of the cooling system is ensured, so that the electric vehicle can run. This will enable, for example, electric vehicles to travel under their own power to a repair shop without having to stop on the road (roadside breakdown), or to travel under their own power to a location where safety can be ensured. Effect of the Invention

[0008] According to the cooling system of the present invention, even if the electric pump does not operate normally, the cooling performance is ensured and the electric vehicle can be driven. [Brief description of the drawings]

[0009] [Figure 1] FIG. 1 is an explanatory diagram of a cooling system according to an application example. [Diagram 2] FIG. 4 is an explanatory diagram of the cooling system when the electric pump is normal. [Diagram 3] FIG. 4 is an explanatory diagram of the cooling system when the electric pump is not operating normally. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The embodiments of the present invention will be described with reference to the drawings. The following embodiments are merely examples, and are not intended to exclude various modifications or application of techniques not specified in the embodiments. The configurations of the following embodiments can be modified in various ways without departing from the spirit of the embodiments. In addition, they can be selected or combined as necessary.

[0011] [1. Configuration] FIG. 1 is an explanatory diagram of a cooling system 10 according to this application example. The cooling system 10 is a facility for cooling a drive motor 11 provided as a power source in an electric vehicle (not shown) using a liquid cooling medium, and is equipped in the electric vehicle (not shown). An example of the liquid refrigerant used in the cooling system 10 is cooling water (coolant liquid). The drive motor 11 is an electric motor connected to wheels 2L, 2R of an electric vehicle (not shown) to drive the wheels 2L, 2R. The vehicle type to which the cooling system 10 is applied is not particularly limited, and examples thereof include passenger cars, buses, and trucks.

[0012] This cooling system 10 includes a radiator 12 for cooling the cooling medium, a cooling circuit 13 that forms a flow path for circulating the cooling medium between the drive motor 11 and the radiator 12, and a pump 14 that forcibly circulates the cooling medium within the cooling circuit 13. The cooling circuit 13 is formed by a plurality of pipes 15 that connect the drive motor 11, the radiator 12, and the pump 14. In the cooling circuit 13, the cooling medium flows in a predetermined flow direction (the flow direction of the cooling medium is indicated by an arrow in FIG. 1). The pump 14 is provided in the cooling circuit 13 and is a pump that pumps the cooling medium in the cooling circuit 13 and forcibly circulates the cooling medium.

[0013] The cooling medium flowing through the cooling circuit 13 is circulated between the drive motor 11 and the radiator 12 by the pump 14, and cools the drive motor 11 as it passes through a water jacket (not shown) of the drive motor 11. The radiator 12 is provided downstream of the drive motor 11 in the cooling circuit 13, and is a heat exchanger for dissipating heat from the cooling medium used to cool the drive motor 11. The cooling medium dissipated heat in the radiator 12 returns to the drive motor 11 through the cooling circuit 13 and is used to cool the drive motor 11.

[0014] As shown in FIG. 1, the cooling system 10 is provided with two pumps 14, an electric pump 14A and a mechanical pump 14B. The electric pump 14A is a pump that is driven by electric power from a power supply device (not shown). The mechanical pump 14B is a pump that is attached to the drive motor 11 and is mechanically driven by the drive motor 11. In other words, the mechanical pump 14B is driven without depending on electric power from a power supply device. The electric pump 14A is a main pump that is used when the electric pump 14A is operating normally (i.e., during normal operation), whereas the mechanical pump 14B can be considered a sub-pump that is used when an abnormality occurs in the electric pump 14A.

[0015] A clutch 16 is provided between the mechanical pump 14B and the drive motor 11. The clutch 16 is a transmission device that connects and disconnects the power transmission between the drive motor 11 and the mechanical pump 14B. When the drive motor 11 and the mechanical pump 14B are connected by the clutch 16, the power of the drive motor 11 is transmitted to the mechanical pump 14B, and the mechanical pump 14B is driven. When the drive motor 11 and the mechanical pump 14B are disconnected by the clutch 16, the power transmission from the drive motor 11 to the mechanical pump 14B is interrupted, and the mechanical pump 14B does not drive.

[0016] As an example, the mechanical pump 14B and the clutch 16 are integrally provided in a casing 11A of the drive motor 11. In this case, there are advantages in that it is not necessary to consider the layout when adding the mechanical pump 14B and clutch 16 to an existing cooling system, and that the power of the drive motor 11 can be easily used to drive the mechanical pump 14B.

[0017] The multiple pipes 15 forming the cooling circuit 13 include a main pipe 15A connected to the drive motor 11, a first branch pipe 15B branching off from the main pipe 15A and connecting to the electric pump 14A, and a second branch pipe 15C branching off from the main pipe 15A and connecting to the mechanical pump 14B. The main pipe 15A is connected to the inlet and outlet of the cooling medium in the drive motor 11, and is also connected to the inlet and outlet of the cooling medium in the radiator 12 provided downstream of the drive motor 11. That is, the cooling medium flows into the drive motor 11 through the main pipe 15A located upstream of the drive motor 11, and is discharged from the drive motor 11 through the main pipe 15A located downstream. The cooling medium discharged from the drive motor 11 flows into the radiator 12 through the main pipe 15A, and is discharged from the radiator 12 through the main pipe 15A located downstream.

[0018] One end of the first branch pipe 15B is connected to the main pipe 15A downstream of the radiator 12, and the other end is connected to the main pipe 15A upstream of the drive motor 11. The electric pump 14A is interposed in this first branch pipe 15B. That is, the first branch pipe 15B is a branch path that branches off from the main pipe 15A and rejoins the main pipe 15A via the electric pump 14A. The first branch pipe 15B and the main pipe 15A form a main circuit that uses the electric pump 14A to circulate the cooling medium between the radiator 12 and the drive motor 11. The main circuit is a main circulation circuit that is used when the electric pump 14A is operating normally.

[0019] The second branch pipe 15C is a flow path separate from the first branch pipe 15B, and has one end connected to the main pipe 15A downstream of the radiator 12 and the other end connected to the main pipe 15A upstream of the drive motor 11. The mechanical pump 14B is interposed in this second branch pipe 15C. That is, the second branch pipe 15C is a branch path that branches off from the main pipe 15A and rejoins the main pipe 15A via the mechanical pump 14B. The second branch pipe 15C and the main pipe 15A form a sub-circuit that uses the mechanical pump 14B to circulate the cooling medium between the radiator 12 and the drive motor 11. The sub-circuit is an auxiliary circulation circuit that is used when an abnormality occurs in the electric pump 14A.

[0020] As shown in FIG. 1, each of the branch pipes 15B and 15C branches off from the main pipe 15A at a common branch point (connection point) and merges into the main pipe 15A at a common junction point (connection point). In the cooling circuit 13, a first switching valve 17A and a second switching valve 17B (switching device) are provided at the branching point and the joining point of the branch pipes 15B, 15C, respectively. Each of the switching valves 17A and 17B is a switching device that switches between a first state in which the cooling medium is circulated through a main circuit and a second state in which the cooling medium is circulated through a sub-circuit.

[0021] When each of the switching valves 17A and 17B is set to the first state, the cooling medium circulates through the main circuit, that is, the main pipe 15A and the first branch pipe 15B. In this case, the second branch pipe 15C is cut off from the main pipe 15A, and the cooling medium does not flow through the sub-circuit. When the switching valves 17A and 17B are set to the second state, the cooling medium circulates through the sub-circuit, that is, the main pipe 15A and the second branch pipe 15C. In this case, the first branch pipe 15B is cut off from the main pipe 15A, and the cooling medium does not flow through the main circuit.

[0022] A specific example of each of the switching valves 17A and 17B shown in FIG. 1 is a three-way valve (3-2 way valve) provided at a position where three pipes 15A, 15B, and 15C intersect. In this case, each of the switching valves 17A and 17B is provided with a first port for opening and closing between the main pipe 15A and the first branch pipe 15B, and a second port for opening and closing between the main pipe 15A and the second branch pipe 15C. When set to the first state, each of the switching valves 17A and 17B opens the first port and closes the second port. On the other hand, when set to the second state, each of the switching valves 17A and 17B closes the first port and opens the second port. Note that, in each of the switching valves 17A and 17B, in a non-energized state, the relay is turned OFF to open the main pipe 15A and the first branch pipe 15B, and in a powered state, the relay is turned ON to open the main pipe 15A and the second branch pipe 15C, but the powered and non-powered states may be configured inversely.

[0023] The cooling circuit 13 is also provided with a sensor 18 for detecting an abnormality in the electric pump 14A. An example of this sensor 18 is a flow rate sensor that detects the flow rate of the cooling medium in the cooling circuit 13. The sensor 18 in FIG. 1 is disposed in the first branch pipe 15B downstream of the electric pump 14A.

[0024] In this specification, an abnormality in the electric pump 14A refers to a state in which the electric pump 14A does not operate normally. When the electric pump 14A operates normally, the cooling medium circulates through the main circuit (cooling circuit 13), but when the electric pump 14A does not operate normally, the cooling medium does not circulate through the main circuit. Therefore, it is possible to detect whether the electric pump 14A is operating normally, i.e., whether there is an abnormality in the electric pump 14A, from the detection result of the flow rate sensor used as the sensor 18. Abnormalities in the electric pump 14A include, for example, a failure of the electrical circuit, such as a short circuit or a broken wire in the electrical circuit that supplies power to the electric pump 14A, or a failure of the electric pump 14A itself due to the intrusion of foreign matter or air into the electric pump 14A.

[0025] In FIG. 1, the control device 19 is an electronic control device for overall control of the cooling system 10, and is configured as, for example, an LSI device or an embedded electronic device integrating a microprocessor, ROM, RAM, and the like. The sensor 18 is connected to the input side of the control device 19, and a detection signal S of the sensor 18 is input. The electric pump 14A, each of the switching valves 17A, 17B, and the clutch 16 are connected to the output side of the control device 19, and control signals C1, C2, C3, and C4 are output from the control device 19 to each of the sections 14A, 17A, 17B, and 16.

[0026] [2. Control] As shown in FIG. 1, the control device 19 has, as functional elements, a determination unit 19A and a signal generation unit 19B. These elements 19A and 19B are shown by classifying the functions of the control device 19 for convenience. These elements 19A and 19B can be written as independent programs, and can also be written as a composite program that combines a plurality of elements 19A and 19B. The programs corresponding to each element are stored in the memory or storage device of the control device 19 and executed by the processor.

[0027] The determination unit 19A determines whether or not an abnormality has occurred in the electric pump 14A based on the detection signal S of the sensor 18. The sensor 18 and the determination unit 19A form a detection device that detects an abnormality in the electric pump 14A. For example, when the sensor 18 is a flow sensor, the determination unit 19A determines whether or not an abnormality has occurred in the electric pump 14A based on the flow rate of the cooling medium. As a specific example, the determination unit 19A may determine that the electric pump 14A is operating normally when the flow rate of the cooling medium is equal to or greater than a predetermined value, and may determine that an abnormality has occurred in the electric pump 14A when the flow rate of the cooling medium is less than the predetermined value. The predetermined value is a value that is set in advance as a predetermined flow rate that can be used to determine whether or not the operation of the electric pump 14A is normal. This predetermined value may be set as appropriate based on simulations, experiments, and the like.

[0028] The signal generating unit 19B generates control signals C1, C2, C3, and C4 to the electric pump 14A, the switching valves 17A and 17B, and the clutch 16 in the cooling system 10 based on the determination result of the determining unit 19A. The control signals C1, C2, C3, and C4 are commands for controlling the operations of the respective units 14A, 17A, 17B, and 16.

[0029] The control signal C1 for the electric pump 14A is a signal that switches the operation of the electric pump 14A on and off. When the electric pump 14A is operating normally (i.e., no abnormality is detected), the signal generating unit 19B outputs the control signal C1 that instructs the electric pump 14A to turn on its operation. When an abnormality in the electric pump 14A is detected, the signal generating unit 19B outputs the control signal C1 that instructs the electric pump 14A to turn off its operation.

[0030] The control signals C2 and C3 for the switching valves 17A and 17B are signals for switching the switching valves 17A and 17B between a first state and a second state. When the electric pump 14A is operating normally, the signal generating unit 19B outputs control signals C2, C3 to set the switching valves 17A, 17B to the first state. When an abnormality in the electric pump 14A is detected, the signal generating unit 19B outputs control signals C2, C3 to set the switching valves 17A, 17B to the second state. Specifically, in order to switch between the first state and the second state, the signal generating unit 19B switches the relays of the switching valves 17A, 17A to an energized state or a de-energized state.

[0031] The control signal C4 for the clutch 16 is a signal that switches between connecting and disconnecting the clutch 16. When the electric pump 14A is operating normally, the signal generating unit 19B outputs the control signal C4 that instructs the clutch 16 to cut off the power. When an abnormality in the electric pump 14A is detected, the signal generating unit 19B outputs the control signal C4 that instructs the clutch 16 to transmit the power.

[0032] FIG. 2 is an explanatory diagram of the cooling system 10 when the electric pump 14A is normal. In this case, the determination unit 19A determines, based on the detection signal S of the sensor 18, that the electric pump 14A is operating normally. The signal generating unit 19B outputs a control signal C1 ("C1:ON" in the drawing) that instructs the electric pump 14A to operate on. The signal generating unit 19B also outputs control signals C2, C3 ("C2:M" and "C3:M" in the drawing) that set the switching valves 17A, 17B to the first state, and outputs a control signal C4 ("C4:OFF" in the drawing) that disengages the clutch 16.

[0033] As a result, each of the switching valves 17A and 17B is set to the first state, and the cooling medium circulates through the main circuit, that is, the main pipe 15A and the first branch pipe 15B. In Fig. 2, the second branch pipe 15C (sub-circuit) through which the cooling medium does not flow is indicated by a dashed line. Furthermore, since the clutch 16 is disengaged, power is not transmitted from the drive motor 11 to the mechanical pump 14B, and therefore the mechanical pump 14B does not operate.

[0034] FIG. 3 is an explanatory diagram of the cooling system 10 when the electric pump 14A is not operating normally. In this case, the determining unit 19A determines, based on the detection signal S of the sensor 18, that an abnormality has occurred in the electric pump 14A. The signal generating unit 19B outputs a control signal C1 ("C1:OFF" in the drawing) that instructs the electric pump 14A to turn off its operation. The signal generating unit 19B also outputs control signals C2, C3 ("C2:S" and "C3:S" in the drawing) that set the switching valves 17A, 17B to the second state, and outputs a control signal C4 ("C4:ON" in the drawing) that engages the clutch 16.

[0035] As a result, each of the switching valves 17A and 17B is set to the second state, and the cooling medium circulates through the sub-circuit, i.e., the main pipe 15A and the second branch pipe 15C. In Fig. 3, the first branch pipe 15B (main circuit), through which the cooling medium does not flow, is indicated by a dashed line. Furthermore, the clutch 16 is connected, so that the power is transmitted from the drive motor 11 to the mechanical pump 14B, causing the mechanical pump 14B to operate.

[0036] [3. Effects] The present embodiment described above provides the following advantageous effects. The cooling circuit 13 of the cooling system 10 in this application example is provided with a sub-circuit that circulates the cooling medium between the radiator 12 and the drive motor 11 using a mechanical pump 14B, and when an abnormality occurs in the electric pump 14A, the cooling medium can be circulated through the sub-circuit using the mechanical pump 14B. Therefore, even if the electric pump 14A does not operate normally due to a failure of the electric circuit that supplies power to the electric pump 14A or a failure of the electric pump 14A itself, the cooling medium can continue to circulate by the sub-circuit using the mechanical pump 14B. Therefore, even if the electric pump 14A does not operate normally, the cooling performance of the cooling system 10 is ensured, so that the electric vehicle can run. As a result, even if the electric pump 14A breaks down while the electric vehicle is traveling, it is possible for the electric vehicle to travel under its own power to a repair shop without having to stop on the road (roadside breakdown), or to a location where safety can be ensured.

[0037] In addition, the mechanical pump 14B, which is the sub-pump, is mechanically driven by the power of the drive motor 11 without using electricity, so the mechanical pump 14B can be driven as long as the electric vehicle can run, that is, the cooling performance of the cooling system 10 is ensured.

[0038] [4.Other] In the above-described cooling system 10, the position of the sensor 18 is not limited to the downstream side of the electric pump 14A in the first branch pipe 15B. For example, the position of the sensor 18 may be the upstream side of the electric pump 14A in the first branch pipe 15B. The sensor 18 is not limited to a flow rate sensor, and may be any sensor that can detect an abnormality in the electric pump 14A. Furthermore, the layout of the first branch pipe 15B, the second branch pipe 15C, and the switching valves 17A and 17B is not limited to the example shown in the figure. The structure of the switching valves 17A, 17B is not limited to the above-mentioned three-way valve, and any well-known structure may be adopted as long as it can switch between a first state in which the cooling medium is circulated through the main circuit and a second state in which the cooling medium is circulated through the sub-circuit. [Explanation of symbols]

[0039] 2L,2R wheels 10 Cooling System 11 Driving motor 11A Casing 12 Radiator 13 Cooling circuit 14 Pump 14A Electric Pump 14B Mechanical pump 15 Pipe 15A Main Pipe 15B First branch pipe 15C Second branch pipe 16 Clutch (transmission device) 17A First switching valve (switching device) 17B Second switching valve (switching device) 18 Sensors (detection devices) 19 Control device 19A Judgment unit (detection device) 19B Signal generation section C1 Control Signal C2 Control Signal C3 Control Signal C4 Control Signal S Detection signal

Claims

[Claim 1] A cooling system that cools a drive motor of an electric vehicle by a cooling medium and cools the cooling medium by a radiator, a cooling circuit including a main circuit that circulates the cooling medium between the radiator and the drive motor using an electric pump that is driven by electric power, and a sub-circuit that circulates the cooling medium between the radiator and the drive motor using a mechanical pump that is mechanically driven by the drive motor; a transmission device that connects and disconnects the power transmission between the drive motor and the mechanical pump; a switching device provided in the cooling circuit and configured to switch between a first state in which the cooling medium is circulated through the main circuit and a second state in which the cooling medium is circulated through the sub-circuit; A detection device that detects an abnormality in the electric pump; a control device which sets the switching device to the first state when no abnormality in the electric pump is detected by the detection device, and which connects the drive motor and the mechanical pump via the transmission device and sets the switching device to the second state when an abnormality in the electric pump is detected by the detection device. A cooling system comprising:

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