JP2018111422A - Cooling system for electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply, in a cooling system mounted in an electric vehicle having two motor generators, cooling liquid to only desired one of the motor generators by a simpler structure.SOLUTION: A cooling system for an electric vehicle comprises: a passage 18a extending from an electric oil pump 22 to an HV motor 12; a passage 18b extending from the electric oil pump 22 to a generator 14; and a passage 18c connecting a node N1 on the passage 18a and a node N2 on the passage 18b. A check valve 24a for allowing circulation toward the HV motor 12 is provided further on the HV motor 12 side than the node N1 of the passage 18a. A check valve 24b for allowing circulation toward the generator 14 is provided further on the generator 14 side than the node N2 of the passage 18b. In addition, a check valve 24c for allowing circulation toward the node N1 is provided between the node N1 and the node N3 and a check valve 24d for allowing circulation toward the node N2 is provided between the node N3 and the node N2.SELECTED DRAWING: Figure 1

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. There are cases where two motor generators are mounted on an electric vehicle. Since these motor generators generate heat in response to 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 in each motor generator may be different. For example, the calorific values of the two motors may differ depending on the vehicle state. In such a case, it is necessary to supply the coolant to the motor generator with a large amount of heat generation, but it may not be necessary to supply the coolant to the motor generator with a small amount of heat generation. In view of this, conventionally, a cooling system that provides a coolant only to one of the two motor generators has been proposed.

  FIG. 6 is a schematic configuration diagram of a cooling system mounted on a conventional electric vehicle, which can switch between two motor generators, that is, a coolant supply to a driving motor generator and a power generation motor generator. It is shown. In the conventional cooling system, the coolant is pumped up by the electric pump and supplied to the coolant switching path. The coolant path switching electric actuator provided in the coolant switching path includes an electrical 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 generating motor generator by switching the flow path of the coolant using the electric actuator as described above. Has been.

JP 2011-225134 A Japanese Unexamined Patent Publication No. 2014-124977

  In a cooling system mounted on an electric vehicle having two motor generators, the coolant can be supplied to only one motor generator by using an electric actuator as in the conventional art. However, the electric actuator has a demerit that the structure is relatively complicated, the number of parts is large, and the structure of the cooling system is complicated. Moreover, the size of the electric actuator is large, and there is a problem that it takes a place for installing the cooling system (which is disadvantageous in terms of mounting).

  An object of the present invention is to supply a coolant only to 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 capable of rotating forward and reverse for sucking and discharging the coolant, and the first A coolant supply path for supplying coolant to the motor generator and the second motor generator, the first supply path extending from one end of the electric pump to the first motor generator, and 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 for supplying the coolant from the coolant supply port to the first supply path; and the second A coolant supply path connected to the supply path and including a fourth supply path for supplying the coolant from the coolant supply port to the second supply path; and the 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; and a second supply path, A second check valve provided on the second motor generator side relative to the connection position of the second supply path and the fourth supply path, and allowing the coolant to flow to the second motor generator side; An electric vehicle cooling system comprising:

  According to the above configuration, when the rotation direction in which the electric pump discharges the cooling liquid sucked from the pump side of the fourth supply path and the second supply path to the first supply path is normal rotation, The coolant is not supplied to the second motor generator, and the coolant is supplied to the first motor generator. Specifically, when the electric pump rotates in the forward 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 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 inflow of air from the open end of the second supply path on the second motor generator side, so that the coolant can be pumped 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 passage allows the coolant to flow to the first motor generator side, the coolant flowing into the first supply passage passes through the first check valve. Supplied to the first motor generator.

  On the other hand, when the rotation direction in which the electric pump discharges the coolant sucked from the third supply path and the pump side of the first supply path to the second supply path is reverse, the first motor The coolant is not 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 coolant 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 coolant to flow to the second motor generator side, the coolant flowing into the second supply path passes through the second check valve. Supplied to the second motor generator.

  As described above, according to the above-described configuration, the two motors have a simple structure as compared with the conventional structure, that is, an electric pump capable of forward and reverse rotation, a coolant supply path, a first check valve, and a second check valve. Coolant can be supplied to only one of the generators.

  Desirably, a third check valve provided in the third supply path and allowing the coolant to flow to the first supply path side, and provided in the fourth supply path and cooled to the second supply path side. And a fourth check valve that allows 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 apparatus further includes a control unit that controls the electric pump, and that determines 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, the coolant can be supplied only to a desired motor generator with a simpler structure.

1 is a schematic configuration diagram of a cooling system for an electric vehicle according to the present embodiment. It is a graph which shows the time change of the temperature of an HV motor and a generator. It is a figure which shows the 1st path | route through which cooling oil flows when an electric oil pump rotates forward. It is a figure which shows the 2nd path | route through which cooling oil flows when an electric oil pump reversely rotates. It is the structure schematic of the modification of the cooling system for electric vehicles. It is a structure schematic diagram of the conventional cooling system for electric vehicles.

  Hereinafter, embodiments of the present invention will be described.

  FIG. 1 is a schematic configuration diagram of a cooling system 10 for an electric vehicle 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 drive motor generator, and serves as a drive source for the hybrid car with electric power from a battery (not shown). The generator 14 is rotated by power from an engine (not shown) to generate electricity and charge the battery. In this embodiment, the electric vehicle cooling system 10 is mounted on a hybrid car, but 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. As a control unit that controls the plurality of check valves 24 a to 24 d provided in the coolant supply path 18 (hereinafter, the check valves 24 a to d are collectively referred to as check valves 24) and the electric oil pump 22. The control ECU 26 is configured.

  The cooling oil 16 flows through the cooling liquid supply path 18 and flows into the HV motor 12 and the generator 14. Thereby, the HV motor 12 and the generator 14 are cooled. The cooling oil 16 flowing through the HV motor 12 and the generator 14 is stored in the oil pan 20 again. Thus, the cooling oil 16 circulates. In the circulation path, a cooler such as a radiator may be provided. In addition, if a cooling mode is adopted in which the HV motor 12 and the generator 14 are covered with a water cooling jacket, other liquids such as water (cooling water) can be used as the cooling liquid.

  The coolant supply path 18 is a flow path 18a as a first supply path extending from one end 22a of the electric oil pump 22 to the HV motor 12, and a flow as a second supply path extending from the other end 22b of the electric oil pump 22 to the generator 14. The passage 18b includes a passage 18c that connects the node N1 in the middle of the passage 18a to the node N2 in the middle of the passage 18b, and a passage 18d that extends from the node N3 in the middle of the passage 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 the end of the flow path 18d on the oil pan 20 side. As shown in FIG. 1, the flow path 18 a is divided into a flow path 18 a-1 from the electric oil pump 22 to the node N <b> 1 and a flow path 18 a-2 from the node N <b> 1 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 channel 18c is divided into a channel 18c-1 from the node N1 to the node N3 and a channel 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 include 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 backward under the control of the control ECU 26. As described above, the electric oil pump 22 performs suction and discharge of the cooling oil 16. The electric oil pump 22 has two ends. When the electric oil pump 22 rotates forward, the one end 22a serves as a discharge end and the other end 22b serves as a suction end. When the electric oil pump 22 rotates in the reverse direction, one end 22a serves as a suction end and the other end. 22b becomes a discharge end. In the present embodiment, when the electric oil pump 22 rotates forward, the cooling oil 16 is sucked 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 flow path 18a-1 and discharged to the flow path 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 in the forward direction from the flow port. When the fluid flows in the forward direction through the flow path provided with the check valve 24, the check ball is separated from the circulation port by the flow of the fluid, and the fluid can circulate through the gap generated thereby. On the other hand, when the fluid flows in the reverse direction through 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 prohibits 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 in the flow path 18a-2 (that is, on the HV motor 12 side of the flow path 18a from the node N1 where the flow path 18a is connected to 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 to flow in the flow path 18b-2 (that is, on the generator 14 side of the flow path 18b with respect to the node N2 where the flow path 18b is connected to 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. Furthermore, a check valve 24d as a fourth check valve is provided in the flow path 18c-2 in a direction that allows the flow of the cooling oil 16 from the node N3 to the node N2.

  A path through which the cooling oil 16 flows in the coolant supply path 18 is formed by the rotation of the electric oil pump 22 and the check valves 24a to 24d. More specifically, the plurality of check valves 24 a to 24 d are provided in the first path where 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 forward. 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 through 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 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 normal rotation control signal for normal rotation of the electric oil pump 22 to the electric oil pump 22, and the electric oil pump 22 that has received the normal rotation control signal starts normal rotation. Further, 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 receiving 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 a normal rotation control signal when the HV motor 12 needs to be cooled (that is, when the HV motor 12 generates a large amount of heat), and when the generator 14 needs to be cooled (that is, the generator 14 generates heat). When the amount is large), a reverse rotation control signal is transmitted.

  The control ECU 26 may determine which of the HV motor 12 and the generator 14 needs to be cooled based on the vehicle state of the hybrid car on which the electric vehicle cooling system 10 is mounted. 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 traveling pattern of the hybrid car and a remaining power (SOC) of the battery.

  FIG. 2 shows a graph showing temporal changes in the temperatures of the HV motor 12 and the generator 14. In each of the two graphs shown in FIG. 2, the horizontal axis indicates time, and the vertical axis indicates temperature.

  FIG. 2 (a) shows a graph when the hybrid car continues to run at a low speed. When the hybrid car travels at a low speed, the driving force from the engine is not used, and only the HV motor 12 is used as a driving source. Therefore, when the hybrid car travels at a low speed, the HV motor 12 continues to operate. As a result, as shown in FIG. 2A, the temperature of the HV motor 12 rises and becomes at least higher than the temperature of the generator 14. That is, in this state, it can be said that it is more necessary to cool the HV motor 12 than the generator 14. Therefore, the control ECU 26 transmits a forward rotation control signal to cool the HV motor 12 when the hybrid car is traveling at a low speed or when the low-speed traveling is continued for a predetermined time.

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

  The schematic configuration of the cooling system 10 for an electric vehicle according to the present embodiment is as described above. Hereinafter, details of the first path that is the path of the cooling oil 16 when the electric oil pump 22 rotates forward, the details of the second path that is the path of the cooling oil 16 when the electric oil pump 22 rotates reversely, and a plurality of reverses 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. Due to the suction force of the electric oil pump 22, the cooling oil 16 is pumped from the oil pan 20 through the oil strainer 28 to the flow path 18d and flows into the flow path 18d. Here, due to the suction force of the electric oil pump 22, the force that flows 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 thereby closing the check valve 24b. This prevents inflow of air from the open end of the flow path 18b-2 on the generator 14 side to the inner side of the check valve 24b (node N2 side), so that the suction force of the electric oil pump 22 causes the oil pan 20 to The cooling oil 16 can be pumped up.

  Further, the suction force of the electric oil pump 22 applies a force that flows from the node N1 side to the node N3 side with respect to the air in the flow path 18c-1 or the cooling oil 16 remaining in the flow path 18c-1. Thereby, 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 cooling oil 16 to flow from the node N3 side to the node N2 side. Therefore, the cooling oil 16 flowing through the flow path 18c-2 passes through the check valve 24d and flows into the node N2. The cooling oil 16 flowing into the node N2 does not flow into the flow path 18b-2 but flows into the flow path 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 into 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 that has flowed through the flow path 18a-1 does not flow from the node N1 to the flow path 18c-1, but all flows to the flow path 18a-2. Inflow. That is, when the check valve 24c is closed, the cooling oil 16 that has flowed through the flow path 18a-1 can be suitably flowed into the flow path 18a-2 (that is, supplied to the HV motor 12).

  The check valve 24a provided in the flow path 18a-2 allows the cooling oil 16 to flow from the node N1 side 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 in the forward direction, the cooling oil 16 is not supplied to the generator 14, and a first path through which the cooling oil 16 is supplied 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. Due to the suction force of the electric oil pump 22, the cooling oil 16 is pumped from the oil pan 20 through the oil strainer 28 to the flow path 18d 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. A force is applied thereby closing the check valve 24a. Accordingly, inflow of air from the open end of the flow path 18a-2 on the HV motor 12 side to the inner side of the check valve 24a (node N1 side) is prevented, so that the oil pan 20 is absorbed by the suction force of the electric oil pump 22. The cooling oil 16 can be pumped from the tank.

  Further, the suction force of the electric oil pump 22 applies a force that flows from the node N2 side to the node N3 side with respect to the air in the flow path 18c-2 or the cooling oil 16 remaining in the flow path 18c-2. 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 cooling oil 16 to flow from the node N3 side to the node N1 side. Therefore, the cooling oil 16 flowing through the flow path 18c-1 passes through the check valve 24c and flows into the node N1. The cooling oil 16 flowing 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 into 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 that has flowed through the flow path 18b-1 does not flow from the node N2 to the flow path 18c-2, but all flows to the flow path 18b-2. Inflow. In other words, since the check valve 24d is closed, the cooling oil 16 that has flowed through the flow path 18b-1 can be preferably introduced into the flow path 18b-2 (that is, supplied to the generator 14).

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

  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 through which the cooling oil 16 is supplied to the generator 14 is formed.

  As described above, according to the cooling system 10 for an electric vehicle according to the present embodiment, there is no need to provide an actuator for switching the flow path, and the electric oil pump 22, the coolant supply path 18, and the plurality of fluid oil paths 18 that can rotate forward and reverse. According to the simple structure of the check valves 24a to 24d, 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 basic embodiment are denoted by the same reference numerals, and description thereof is omitted. In the basic embodiment, the flow path 18d is shared by the third supply path and the fourth supply path. However, like the modified coolant supply path 18-2, two flow paths 18d are provided. 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 provided separately. 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 basic embodiment can be omitted. Since the operation or action of the electric vehicle cooling system 10-2 is the same as that of the basic embodiment, the description thereof is omitted.

  As mentioned above, although embodiment which concerns on this invention was described, this invention is not limited to the said embodiment, A various change is possible unless it deviates from the meaning of this invention.

  DESCRIPTION OF SYMBOLS 10 Cooling system for electric vehicles, 12 HV motor, 14 generator, 16 cooling oil, 18 coolant 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,
An electric pump capable of rotating in forward and reverse directions for sucking and discharging the coolant;
A coolant supply path for supplying coolant to the first motor generator and the second motor generator, the first supply path extending from one end of the electric pump to the first motor generator, and the electric pump 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 the coolant from the coolant supply port to the first supply path; A coolant supply path connected to the second supply path and including a fourth supply path for supplying the coolant from the coolant supply port to the second supply path;
The first supply path is provided closer to the first motor generator side than the connection position between the first supply path and the third supply path, and allows the coolant to flow to the first motor generator side. 1 check valve,
The second supply path is provided closer to the second motor generator side than the connection position between the second supply path and the fourth supply path, and allows the coolant to flow to the second motor generator side. 2 check valves,
A cooling system for an electric vehicle comprising: