JP6658558B2 - Cooling system for electric vehicles - Google Patents

Description

  The present invention relates to a cooling system for an electric vehicle.

  Conventionally, an electric vehicle using a motor generator as a drive source is known. Examples of the electric vehicle include a hybrid vehicle and an electric vehicle. In some cases, two motor generators are mounted on an electric vehicle. Since these motor generators generate heat in accordance with the operation, a cooling system for cooling the motor generator by supplying a coolant to the motor generator has been proposed.

  When two motor generators are mounted on an electric vehicle, the amount of heat generated by each motor generator may be different. For example, the amount of heat generated by the two motors may differ depending on the state of the vehicle. In such a case, it is necessary to supply the coolant to the motor generator having a large amount of heat generation, but it may not be necessary to supply the coolant to the motor generator having a small amount of heat generation. In view of this, conventionally, a cooling system that supplies a coolant to only one of the two motor generators has been proposed.

  FIG. 6 is a schematic configuration diagram of a conventional cooling system mounted on an electric vehicle, which is capable of switching supply of a coolant to two motor generators, that is, a driving motor generator and a power generation motor generator. It is shown. In a conventional cooling system, a coolant is pumped by an electric pump and supplied to a coolant switching path. The electric actuator for switching the coolant passage provided in the coolant switching passage includes an electric switching valve that is opened and closed under the control of the control ECU. By opening and closing the electric switching valve, the flow path of the coolant is switched between the flow path to the drive motor generator and the flow path to the power generation motor generator.

  Patent Documents 1 and 2 also disclose a cooling system capable of supplying a coolant to one of a driving motor generator and a power generation motor generator by switching the coolant flow path by the above-described electric actuator. Have been.

JP 2011-225134 A JP 2014-124977 A

  In a cooling system mounted on an electric vehicle having two motor generators, the cooling fluid can be supplied to only one of the motor generators by using an electric actuator as in the related art. However, the electric actuator has the disadvantage that the structure is relatively complicated, the number of parts is large, and the structure of the cooling system is complicated. In addition, the electric actuator has a large size, and there is also a problem that a space for installing the cooling system is required (it is disadvantageous in terms of mounting).

  An object of the present invention is to supply a coolant to only a desired motor generator with a simpler structure in a cooling system mounted on an electric vehicle having two motor generators.

The present invention is a cooling system for an electric vehicle mounted on an electric vehicle having a first motor generator and a second motor generator, the electric pump being capable of rotating forward and reverse for sucking and discharging a cooling liquid, and A coolant supply path for supplying coolant to the motor generator and the second motor generator, a first supply path extending from one end of the electric pump to the first motor generator, and a second supply path extending from the other end of the electric pump. A second supply path extending to the second motor generator, a third supply path connected to the first supply path, and configured to supply a coolant from a coolant supply port to the first supply path; A coolant supply path connected to a supply path and including a fourth supply path for supplying coolant from a coolant supply port to the second supply path; and a first supply path of the first supply path. A first check valve that is provided closer to the first motor generator than a connection position with the third supply path and that allows a coolant to flow to the first motor generator side; A second check valve that is provided closer to the second motor generator than a connection position between the second supply path and the fourth supply path, and that allows the flow of the coolant to the second motor generator. When the electric pump rotates forward, the coolant is supplied to the first motor generator and the coolant is not supplied to the second motor generator in the coolant supply path. When a first path is formed and the electric pump rotates in the reverse direction, the coolant is supplied to the second motor generator in the coolant supply path, and the first motor generator Wherein the cooling fluid is not supplied the second path of the cooling liquid is formed, it is an electric vehicle cooling system according to claim.

  According to the above configuration, when the rotation direction in which the electric pump discharges the coolant sucked from the pump side of the fourth supply path and the second supply path to the first supply path is set to the forward rotation, when the electric pump rotates forward, , The coolant is not supplied to the second motor generator, but the coolant is supplied to the first motor generator. Specifically, when the electric pump rotates forward, the cooling liquid is pumped from the cooling liquid supply port by the suction force of the electric pump, and is supplied to the second supply path through the fourth supply path. Here, the second check valve provided in the second supply path is closed by the suction force of the electric pump. This prevents the inflow of air from the open end of the second supply path on the side of the second motor generator, so that it is possible to pump the coolant by the suction force of the electric pump. The coolant supplied to the second supply path flows into the first supply path via the electric pump. Since the first check valve provided in the first supply path allows the flow of the coolant to the first motor generator side, the coolant flowing into the first supply path passes through the first check valve. It is supplied to the first motor generator.

  On the other hand, if the rotation direction in which the electric pump discharges the coolant sucked from the pump side of the third supply path and the first supply path to the second supply path is reverse rotation, when the electric pump rotates reversely, the first motor No coolant is supplied to the generator, and the coolant is supplied to the second motor generator. Specifically, when the electric pump rotates in the reverse direction, the cooling liquid is pumped up from the cooling liquid supply port by the suction force of the electric pump, and is supplied to the first supply path through the third supply path. Here, the first check valve provided in the first supply path is closed by the suction force of the electric pump. This prevents the inflow of air from the open end of the first supply path on the first motor generator side, so that the coolant can be pumped by the suction force of the electric pump. The cooling liquid supplied to the first supply path flows into the second supply path via the electric pump. Since the second check valve provided in the second supply path allows the flow of the coolant to the second motor generator side, the coolant flowing into the second supply path passes through the second check valve. It is supplied to the second motor generator.

  As described above, according to the above configuration, the two motors are configured by a simpler structure as compared with the related art, such as the electric pump capable of rotating in the forward and reverse directions, the coolant supply path, the first check valve, and the second check valve. The coolant can be supplied to only one of the generators.

  Desirably, a third check valve provided in the third supply path and allowing the flow of the cooling liquid to the first supply path side, and cooling provided to the fourth supply path and cooling to the second supply path side A fourth check valve that permits the flow of the liquid. According to this structure, the flow path from the coolant supply port to the third check valve and the fourth check valve can be shared.

  Preferably, the control unit further includes a control unit for controlling the electric pump, the control unit determining a rotation direction of the electric pump according to a vehicle state of the electric vehicle.

  According to the present invention, in a cooling system mounted on an electric vehicle having two motor generators, it is possible to supply the coolant only to the desired motor generator with a simpler structure.

1 is a schematic configuration diagram of a cooling system for an electric vehicle according to an embodiment. 5 is a graph showing a time change of the temperature of the HV motor and the generator. FIG. 4 is a diagram illustrating a first path through which cooling oil flows when the electric oil pump rotates forward. It is a figure showing the 2nd course in which cooling oil flows when an electric oil pump rotates reversely. It is a structure schematic diagram of a modification of the cooling system for electric vehicles. It is a schematic diagram of a configuration of a conventional electric vehicle cooling system.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of an electric vehicle cooling system 10 according to the present embodiment, which is mounted on a hybrid car as an electric vehicle. The electric vehicle cooling system 10 is a system for cooling the HV motor 12 as a first motor generator and the generator 14 as a second motor generator. The HV motor 12 is a driving motor generator, and serves as a driving source of a hybrid car by electric power from a battery (not shown). The generator 14 is rotated by power from an engine (not shown) to generate electric power and charge the battery. In the present embodiment, the electric vehicle cooling system 10 is mounted on a hybrid car. However, the electric vehicle cooling system 10 may be mounted on another electric vehicle such as an electric vehicle having two motor generators. Good.

  The electric vehicle cooling system 10 includes a cooling liquid supply path 18 for supplying a cooling oil 16 as a cooling liquid to the HV motor 12 and the generator 14, and an electric oil pump 22 as an electric pump for sucking and discharging the cooling oil 16. A plurality of check valves 24 a to 24 d provided in the coolant supply passage 18 (hereinafter, the check valves 24 a to 24 d are collectively referred to as a check valve 24), and a control unit for controlling the electric oil pump 22. The control ECU 26 is included.

  The cooling oil 16 flows around the HV motor 12 and the generator 14 through the cooling liquid supply path 18. Thereby, HV motor 12 and generator 14 are cooled. The cooling oil 16 flowing around the HV motor 12 and the generator 14 is stored in the oil pan 20 again. Thus, the cooling oil 16 is circulating. A cooler such as a radiator may be provided in the circulation path. Further, if a mode is adopted in which the HV motor 12 and the generator 14 are covered with a water-cooling jacket for cooling, another liquid such as water (cooling water) can be used as the cooling liquid.

  The coolant supply passage 18 has a flow passage 18 a as a first supply passage extending from one end 22 a of the electric oil pump 22 to the HV motor 12, and a flow passage as a second supply passage extending from the other end 22 b of the electric oil pump 22 to the generator 14. The path 18b includes a flow path 18c connecting the node N1 in the middle of the flow path 18a to the node N2 in the middle of the flow path 18b, and a flow path 18d extending from the node N3 in the middle of the flow path 18c to the oil pan 20. It is configured. Here, the node N1 is a connection position between the flow path 18a and the flow path 18c, and the node N2 is a connection position between the flow path 18b and the flow path 18c. An oil strainer 28 for sucking the cooling oil 16 and removing solid matter mixed in the cooling oil 16 is provided at an end of the flow path 18d on the oil pan 20 side as a cooling liquid supply port. As shown in FIG. 1, the flow path 18a is divided into a flow path 18a-1 from the electric oil pump 22 to the node N1, and a flow path 18a-2 from the node N1 to the HV motor 12. The flow path 18b is divided into a flow path 18b-1 from the electric oil pump 22 to the node N2 and a flow path 18b-2 from the node N2 to the generator 14. The flow path 18c is divided into a flow path 18c-1 from the node N1 to the node N3 and a flow path 18c-2 from the node N3 to the node N2. The flow path 18d and the flow path 18c-1 constitute a third supply path for supplying the cooling oil 16 from the oil strainer 28 to the flow path 18a. Similarly, the flow path 18d and the flow path 18c-2 A fourth supply path for supplying the cooling oil 16 from the oil strainer 28 to the flow path 18b is configured.

  The electric oil pump 22 is an electric pump that can rotate forward and reverse under the control of the control ECU 26. As described above, the electric oil pump 22 suctions and discharges the cooling oil 16. The electric oil pump 22 has two ends, and when rotated forward, one end 22a becomes a discharge end and the other end 22b becomes a suction end, and when rotated reversely, one end 22a becomes a suction end and the other end. 22b is the discharge end. In this embodiment, when the electric oil pump 22 rotates forward, the cooling oil 16 is suctioned from the flow path 18b-1 and discharged to the flow path 18a-1. On the other hand, when the electric oil pump 22 rotates in the reverse direction, the cooling oil 16 is sucked from the channel 18a-1 and discharged to the channel 18b-1.

  The check valve 24 allows the fluid to flow in the forward direction, but prohibits the flow in the reverse direction. The check valve 24 has a very simple structure and includes, for example, a flow port through which a fluid flows, and a check ball provided downstream of the flow port in the forward direction. When the fluid flows in the forward direction in the flow path in which the check valve 24 is provided, the check ball is separated from the flow port by the flow of the fluid, and the fluid can flow through a gap generated thereby. On the other hand, when the fluid flows in the reverse direction in the flow path provided with the check valve 24, the check ball is pressed against the flow port by the back pressure of the fluid, and the flow port is closed. This inhibits fluid flow.

  In the present embodiment, four check valves 24 are provided. Specifically, the cooling oil 16 from the node N1 to the HV motor 12 is provided to the flow path 18a-2 (that is, the HV motor 12 side from the node N1 which is the connection position of the flow path 18a with the flow path 18c-1). A check valve 24a as a first check valve is provided in a direction that allows the flow of air. Further, the flow of the cooling oil 16 from the node N2 to the generator 14 is allowed in the flow path 18b-2 (that is, the flow path 18b is closer to the generator 14 than the node N2 which is the connection position with the flow path 18c-2). A check valve 24b as a second check valve is provided in the direction. Further, a check valve 24c as a third check valve is provided in the flow path 18c-1 in a direction that allows the flow of the cooling oil 16 from the node N3 to the node N1. Further, a check valve 24d as a fourth check valve is provided in the flow path 18c-2 in a direction allowing the flow of the cooling oil 16 from the node N3 to the node N2.

  The rotation of the electric oil pump 22 and the plurality of check valves 24 a to 24 d form a passage through which the cooling oil 16 flows in the cooling liquid supply passage 18. More specifically, the plurality of check valves 24 a to 24 d are configured such that when the electric oil pump 22 rotates forward, the cooling oil 16 is supplied to the HV motor 12 and the cooling oil 16 is not supplied to the generator 14. When the electric oil pump 22 rotates in the reverse direction, the cooling oil 16 is supplied to the generator 14 and the second path in which the cooling oil 16 is not supplied to the HV motor 12 is formed. Details of the first path and the second path, and the operation of the plurality of check valves 24a to 24d will be described later.

  The control ECU 26 controls the electric oil pump 22 by transmitting a control signal to the electric oil pump 22. Specifically, the control ECU 26 transmits a forward rotation control signal for rotating the electric oil pump 22 in the forward direction to the electric oil pump 22, and the electric oil pump 22 receiving the signal starts the forward rotation. In addition, the control ECU 26 transmits a reverse rotation control signal for reversely rotating the electric oil pump 22 to the electric oil pump 22, and the electric oil pump 22 that has received the reverse rotation control signal starts reverse rotation.

  As described above, when the electric oil pump 22 rotates forward, the cooling oil 16 is supplied only to the HV motor 12, and when the electric oil pump 22 rotates reversely, the cooling oil 16 is supplied only to the generator 14. Therefore, the control ECU 26 transmits the forward rotation control signal when the HV motor 12 needs to be cooled (ie, when the HV motor 12 generates a large amount of heat), and when the generator 14 needs to be cooled (ie, when the HV motor 12 needs to be cooled). When the amount is large, the reverse rotation control signal is transmitted.

  The control ECU 26 may determine which of the HV motor 12 and the generator 14 needs cooling based on the vehicle state of the hybrid car equipped with the electric vehicle cooling system 10. That is, the control ECU 26 may determine the rotation direction of the electric oil pump 22 based on the vehicle state of the hybrid car. The vehicle state is a concept including a running pattern of the hybrid car and a state of charge (SOC) of the battery.

  FIG. 2 is a graph showing a time change of the temperature of the HV motor 12 and the temperature of the generator 14. In each of the two graphs shown in FIG. 2, the horizontal axis represents time, and the vertical axis represents temperature.

  FIG. 2A shows a graph when the hybrid car continues to run at low speed. When the hybrid car travels at a low speed, only the HV motor 12 is used as a driving source without using the driving force from the engine. Therefore, when the hybrid car runs at low speed, the HV motor 12 continues to operate. As a result, as shown in FIG. 2A, the temperature of the HV motor 12 increases, and at least becomes higher than the temperature of the generator 14. That is, in this state, it can be said that the need to cool the HV motor 12 is higher than that of the generator 14. Therefore, when the hybrid car is running at a low speed or when the low-speed running is continued for a predetermined time, control ECU 26 transmits a forward rotation control signal to cool HV motor 12.

  FIG. 2B shows a graph when the SOC of the battery is low (for example, when the SOC is 20%). When the SOC is low, the battery needs to be charged, so that the generator 14 operates. In particular, when the SOC is low, the generator 14 operates continuously. As a result, as shown in FIG. 2B, the temperature of the generator 14 increases and becomes higher than at least the temperature of the HV motor 12. That is, in this state, it can be said that the necessity of cooling the generator 14 is higher than that of the HV motor 12. Therefore, when the SOC of the battery is low, control ECU 26 transmits a reverse rotation control signal to cool generator 14.

  The schematic configuration of the electric vehicle cooling system 10 according to the present embodiment is as described above. Hereinafter, details of a first path which is a path of the cooling oil 16 when the electric oil pump 22 rotates forward, a second path which is a path of the cooling oil 16 when the electric oil pump 22 rotates reversely, and a plurality of reverse paths The operation of the stop valves 24a to 24d will be described.

  FIG. 3 shows a first path formed when the electric oil pump 22 rotates forward. When the electric oil pump 22 rotates forward, the electric oil pump 22 discharges the cooling oil 16 sucked from the flow path 18b-1 to the flow path 18a-1. By the suction force of the electric oil pump 22, the cooling oil 16 is pumped from the oil pan 20 to the flow path 18d via the oil strainer 28, and flows into the flow path 18d. Here, due to the suction force of the electric oil pump 22, a force flowing from the generator 14 side to the node N2 side with respect to the air in the flow path 18b-2 or the cooling oil 16 remaining in the flow path 18b-2. Is added, whereby the check valve 24b is closed. This prevents air from flowing from the open end of the flow path 18b-2 on the generator 14 side to the inside of the check valve 24b (on the node N2 side). The cooling oil 16 can be pumped.

  Further, a force flowing from the node N1 to the node N3 is applied to the air in the flow path 18c-1 or the cooling oil 16 remaining in the flow path 18c-1 by the suction force of the electric oil pump 22. , Whereby the check valve 24c is closed.

  The cooling oil 16 that has flowed into the flow path 18d flows into the flow path 18c-2 via the node N3. The check valve 24d provided in the flow path 18c-2 allows the flow of the cooling oil 16 from the node N3 to the node N2. Therefore, the cooling oil 16 flowing through the flow path 18c-2 flows into the node N2 through the check valve 24d. The cooling oil 16 flowing into the node N2 does not flow into the flow channel 18b-2 but flows into the flow channel 18b-1 due to the suction force of the electric oil pump 22. That is, the cooling oil 16 does not flow to the generator 14 side.

  The cooling oil 16 flowing through the flow path 18b-1 is sucked by the electric oil pump 22 and discharged to the flow path 18a-1. As described above, since the check valve 24c is closed, the cooling oil 16 flowing through the flow path 18a-1 does not flow from the node N1 to the flow path 18c-1, but all flows into the flow path 18a-2. Inflow. That is, by closing the check valve 24c, the cooling oil 16 that has flowed through the flow path 18a-1 can appropriately flow into the flow path 18a-2 (that is, be supplied to the HV motor 12).

  The check valve 24a provided in the flow path 18a-2 allows the flow of the cooling oil 16 from the node N1 to the HV motor 12 side. Therefore, the cooling oil 16 flowing through the flow path 18a-2 passes through the check valve 24a and is supplied to the HV motor 12.

  As described above, when the electric oil pump 22 rotates forward, the cooling oil 16 is not supplied to the generator 14, and a first path for supplying the cooling oil 16 to the HV motor 12 is formed.

  FIG. 4 shows a second path formed when the electric oil pump 22 rotates in the reverse direction. When the electric oil pump 22 rotates in the reverse direction, the electric oil pump 22 discharges the cooling oil 16 sucked from the flow path 18a-1 to the flow path 18b-1. By the suction force of the electric oil pump 22, the cooling oil 16 is pumped from the oil pan 20 to the flow path 18d via the oil strainer 28, and flows into the flow path 18d. Here, the suction force of the electric oil pump 22 causes the air in the flow path 18a-2 or the cooling oil 16 remaining in the flow path 18a-2 to flow from the HV motor 12 side to the node N1 side. Force is applied, thereby closing check valve 24a. This prevents air from flowing from the open end of the flow path 18a-2 on the HV motor 12 side to the inside of the check valve 24a (node N1 side), so that the oil pan 20 is sucked by the electric oil pump 22. The cooling oil 16 can be pumped from the pump.

  Further, a force flowing from the node N2 to the node N3 is applied to the air in the flow path 18c-2 or the cooling oil 16 remaining in the flow path 18c-2 by the suction force of the electric oil pump 22. Thereby, the check valve 24d is closed.

  The cooling oil 16 that has flowed into the flow path 18d flows into the flow path 18c-1 via the node N3. The check valve 24c provided in the flow path 18c-1 allows the flow of the cooling oil 16 from the node N3 to the node N1. Therefore, the cooling oil 16 flowing through the flow path 18c-1 flows into the node N1 through the check valve 24c. The cooling oil 16 that has flowed into the node N1 does not flow into the flow path 18a-2 but flows into the flow path 18a-1 due to the suction force of the electric oil pump 22. That is, the cooling oil 16 does not flow to the HV motor 12 side.

  The cooling oil 16 flowing through the flow path 18a-1 is sucked by the electric oil pump 22 and discharged to the flow path 18b-1. As described above, since the check valve 24d is closed, the cooling oil 16 flowing through the flow path 18b-1 does not flow from the node N2 to the flow path 18c-2, but all flows into the flow path 18b-2. Inflow. That is, by closing the check valve 24d, the cooling oil 16 that has flowed through the flow path 18b-1 can appropriately flow into the flow path 18b-2 (that is, can be supplied to the generator 14).

  The check valve 24b provided in the flow path 18b-2 allows the flow of the cooling oil 16 from the node N2 side to the generator 14 side. Therefore, the cooling oil 16 flowing through the flow path 18b-2 is supplied to the generator 14 through the check valve 24b.

  As described above, when the electric oil pump 22 rotates in the reverse direction, the cooling oil 16 is not supplied to the HV motor 12, and a second path for supplying the cooling oil 16 to the generator 14 is formed.

  As described above, according to the electric vehicle cooling system 10 according to the present embodiment, the electric oil pump 22 that can rotate in the forward and reverse directions, the coolant supply path 18, and the , The cooling oil 16 can be supplied to only one of the HV motor 12 and the generator 14 in accordance with the rotation direction of the electric oil pump 22.

  FIG. 5 shows an electric vehicle cooling system 10-2 according to a modification. In FIG. 5, the same components as those in the above-described basic embodiment are denoted by the same reference numerals, and description thereof is omitted. In the above-described basic embodiment, the flow path 18d is shared between the third supply path and the fourth supply path. However, two flow paths 18d are provided like the coolant supply path 18-2 of the modified example. It may be. Specifically, the flow path 18d-1 connected from the oil strainer 28a to the flow path 18c-1 and the flow path 18d-2 connected from the oil strainer 28b to the flow path 18c-2 may be separately provided. Good. In the modification, the check valve 24c provided in the flow path 18c-1 and the check valve 24d provided in the flow path 18c-2 in the above-described basic embodiment can be omitted. The operation or operation of the electric vehicle cooling system 10-2 is the same as that of the above-described basic embodiment, and thus the description thereof is omitted.

  The embodiment according to the present invention has been described above, but the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.

  Reference Signs List 10 cooling system for electric vehicle, 12 HV motor, 14 generator, 16 cooling oil, 18 cooling liquid supply path, 20 oil pan, 22 electric oil pump, 24a-d check valve, 26 control ECU.

Claims (1)

An electric vehicle cooling system mounted on an electric vehicle having a first motor generator and a second motor generator,
A forward / reverse rotatable electric pump for sucking and discharging the coolant,
A coolant supply path for supplying coolant to the first motor generator and the second motor generator, a first supply path extending from one end of the electric pump to the first motor generator, A second supply path extending from the other end to the second motor generator, a third supply path connected to the first supply path, for supplying a coolant from a coolant supply port to the first supply path, A coolant supply path connected to the second supply path, the coolant supply path including a fourth supply path for supplying coolant from the coolant supply port to the second supply path;
The first supply path is provided closer to the first motor generator than a connection position between the first supply path and the third supply path, and allows a coolant to flow to the first motor generator. One check valve,
The second supply path is provided closer to the second motor generator than a connection position between the second supply path and the fourth supply path, and allows a coolant to flow to the second motor generator. Two check valves;
Equipped with a,
When the electric pump rotates forward, in the coolant supply passage, the coolant is supplied to the first motor generator, and the first coolant of the coolant is not supplied to the second motor generator. When a path is formed and the electric pump rotates in the reverse direction, the coolant is supplied to the second motor generator in the coolant supply path, and the coolant is not supplied to the first motor generator. A second path for the cooling liquid is formed;
A cooling system for an electric vehicle, comprising: