JP2013150466A - Electric vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control damage of a cooler in an electric vehicle.SOLUTION: An electric vehicle 100 includes: a motor generator 11; a common coolant flow path 20 to make the coolant conduct to an inverter 12; a radiator 15 to be connected with the coolant flow path 20; a bypass pipe 30 to be connected in parallel with a radiator 15 through switching valves 16 and 18; a coolant pump 14 installed in the coolant flow path 20; a controller 50 that switches the switching valves 16 and 18 and starts and stops the coolant pump 14. The controller 50 switches the switching valves 16 and 18 to the bypass flow path side when turned on after the vehicle start switch 32 is turned off in the running, and includes a restart means to start the coolant pump 14.

Description

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

  In an electric vehicle or a hybrid vehicle, various electric devices such as a drive motor, an inverter that converts DC power from a battery into drive power supplied to the drive motor or boosts the drive voltage, and a DC / DC converter are provided. A cooling device is provided that cools each electrical device by circulating a coolant in each electrical device so that the temperature can be maintained at an optimum temperature for operation (see, for example, Patent Document 1). In addition, a cooling device that recirculates the coolant to the battery and the power control unit has also been proposed (see, for example, Patent Documents 2 and 3).

  The prior art cooling device described in Patent Document 1 has two cooling systems, a cooling system for electric devices such as a motor and an inverter, and a cooling system for an air conditioner that cools the room. When the cooling system is activated, in order to prevent the cooling capacity of the electrical equipment cooling system from being reduced by the released heat, the cooling system refrigerant for the air conditioner and the cooling system refrigerant for the electrical equipment There has been proposed a method in which a heat exchanger for exchanging heat between them is arranged so that the cooling capacity of the electric device is not lowered and the temperature of the electric device is not increased even when the air conditioner is operated.

  The prior art cooling device described in Patent Document 2 is configured to cool the battery in addition to the motor and the inverter. When the battery is at a low temperature, the cooling liquid is circulated without flowing to the radiator. In addition, it has been proposed to raise the temperature of the battery to an appropriate temperature by performing a temperature raising operation of the inverter.

  In the prior art described in Patent Document 3, a heater is provided in the cooling system, and when the temperature of the cooling water is low, the temperature of the PCU, the motor, and the battery is increased by increasing the temperature of the cooling water by the heater. The temperature is raised to an appropriate temperature, and after the temperature rises, the cooling water whose temperature has risen through each electrical device is cooled by flowing to the radiator so that the temperature of each electrical device is within an appropriate range for operation. Has been proposed.

  On the other hand, in a fuel cell vehicle using a fuel cell, a larger cooling device is required to maintain a fuel cell that releases a larger amount of heat than an electric device such as a motor or an inverter at an appropriate operating temperature. In a large cooling device, the length of the heat exchanger tube is long and large, so if the temperature difference between the temperature of the cooling water flowing into the heat exchanger and the temperature of the heat exchanger is large, The heat exchanger may be damaged. For this reason, when the temperature difference between the cooling water in the heat exchanger and the cooling water flowing into the heat exchanger is large, the cooling water can be bypassed and the cooling water can be flown through There has been proposed a method for suppressing the occurrence of damage in the heat exchanger by gradually introducing it into the furnace (for example, see Patent Document 4).

JP 2010-167886 A JP 2008-189249 A JP 2011-182607 A JP 2006-224879 A

  By the way, in the cooling device for the electric device of the electric vehicle as described in Patent Document 2, the temperature of the electric device such as a battery or the temperature of the cooling water after cooling the electric device is detected, and the temperature is determined according to the temperature. Change the opening direction of the switching valve that switches the flow path between the radiator (cooler) and the bypass pipe to adjust the flow rate of the cooling water passing through the radiator so that the temperature of each electrical device is within the appropriate temperature range. Yes. For this reason, as described in Patent Document 4, there is almost no case where the switching valve instantly switches to the radiator side and high-temperature cooling water flows into the radiator at once, and the radiator is not damaged by thermal shock. It was.

  However, in an electric vehicle, when the vehicle start switch for starting the vehicle during driving is turned on after being turned off, the circulation of the cooling water is stopped by turning off the vehicle start switch, and the motor or inverter The cooling water staying in the cooling water flow path is heated by the residual heat of each electric device and the heat generated by the motor due to the vehicle traveling by inertia, and the temperature rises greatly. After that, when the vehicle start switch is turned on, the control device detects the temperature of the cooling water near the portion where the temperature has risen or the temperature of the electric device where the temperature has risen, and tries to cool each electric device rapidly. For this reason, the control device may fully open the switching valve to the radiator side so that the cooling water can rapidly flow into the radiator. In this case, the high-temperature cooling water flows into the radiator (cooler) at once, and the radiator (cooler) may be damaged by thermal shock.

  Then, an object of this invention is to suppress damage to a cooler in an electric vehicle.

  The electric vehicle of the present invention is connected in series to the refrigerant flow path, the common refrigerant flow path for allowing the refrigerant to flow to the drive motor and the power source that supplies power to the drive motor, and the refrigerant is A cooler for cooling, a bypass channel connected to the refrigerant channel in parallel with the cooler via a switching valve, bypassing the cooler, a refrigerant pump provided in the refrigerant channel, and the switching valve And a control unit for starting and stopping the refrigerant pump, and when the control unit is turned on after the vehicle start switch is turned off during traveling, the control valve In addition to switching to the bypass flow path side, restarting means for starting the refrigerant pump is provided.

  In the electric vehicle according to the present invention, the restarting means switches the switching valve to an intermediate position where the refrigerant flows between the bypass flow path side and the cooler side after the first predetermined time has elapsed after the refrigerant pump is started. It is also preferable that the restarting means switch the switching valve to the cooler side after a second predetermined time has elapsed after switching the switching valve to the intermediate position.

  Further, in the electric vehicle according to the present invention, the restarting means changes the first and second predetermined times according to the time until the vehicle start switch is turned on after the vehicle start switch is turned off during traveling. It is also preferable that the restart means increases the first and second predetermined times as the time until the vehicle start switch is turned on after the vehicle start switch is turned off during traveling is longer. The vehicle speed sensor for detecting the vehicle speed is suitable, and the restarting means of the control unit has a vehicle speed detected by the vehicle speed sensor when the vehicle start switch is turned off. The larger the value, the longer the first and second predetermined times are.

  The present invention has an effect of suppressing damage to a cooler in an electric vehicle.

It is a distribution diagram showing the composition of the electric vehicle in the embodiment of the present invention. It is a flowchart which shows operation | movement of the electric vehicle in embodiment of this invention. It is explanatory drawing which shows the flow of the refrigerant | coolant of the electric vehicle in embodiment of this invention. It is explanatory drawing which shows the flow of the refrigerant | coolant of the electric vehicle in embodiment of this invention. It is a flowchart which shows the other operation | movement of the electric vehicle in embodiment of this invention. It is a graph which shows the relationship between the time between OFF-ON of the vehicle start switch of the electric vehicle in embodiment of this invention, and the 1st, 2nd predetermined time. It is a graph which shows the relationship between the vehicle speed at the time of vehicle starting switch-off of the electric vehicle in embodiment of this invention, and 1st, 2nd predetermined time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIG. 1, an electric vehicle 100 according to the present embodiment includes a motor generator 11 that is a drive motor for driving the electric vehicle 100, and direct current power of a battery (not shown) to alternating current power for driving the motor generator 11. An inverter 12 that is a power source to be converted, and a refrigerant flow path 20 that allows the refrigerant to flow through the motor generator 11 and the inverter 12 that is a power source are provided. Each of the motor generator 11 and the inverter 12 has an internal flow path (not shown) through which a refrigerant flows. The refrigerant flow path 20 is provided with a refrigerant pump 14 for circulating the refrigerant and a reservoir tank 13 for storing the refrigerant. The refrigerant flow path 20 includes an inverter inlet pipe 21, a reservoir tank inlet pipe 22, a refrigerant pump inlet pipe 23, a motor generator inlet pipe 24, a motor generator outlet pipe 25, and an inverter 12, an internal flow path of the motor generator 11, a reservoir tank. 13, including a refrigerant pump 14.

  Switching valves 16 and 18 are attached to one end of the inverter inlet pipe 21 and the motor generator outlet pipe 25, respectively. The switching valves 16 and 18 are three-way valves, and each has two connection ends in addition to the connection ends of the inverter inlet pipe 21 and the motor generator outlet pipe 25. A radiator main body 15a, which is a cooler for cooling the refrigerant, is connected to a connection end of each of the switching valves 16 and 18 via a radiator inlet pipe 15b and a radiator outlet pipe 15c. The radiator main body 15a, the radiator inlet pipe 15b, and the radiator outlet pipe 15c constitute a radiator 15 that is a cooler. A bypass pipe 30 is connected between the other connection ends so as to be in parallel with the radiator 15. Actuators 17 and 19 are attached to the switching valves 16 and 18 to move the valve bodies provided therein to switch the internal flow path between the radiator side and the bypass pipe side.

  The electric vehicle 100 includes a control unit 50 that controls the motor generator 11 and the inverter 12. The control unit 50 is a computer including a CPU and a memory for signal processing inside. The control unit 50 is connected to the motor generator 11, the inverter 12, the refrigerant pump 14, and the actuators 17 and 19, and each device is configured to operate according to a command from the control unit 50. In FIG. 1, the alternate long and short dash line indicates a signal line.

  The electric vehicle 100 is provided with a vehicle speed sensor 31 that detects the vehicle speed. The vehicle speed sensor 31 is connected to the control unit 50, and the control unit 50 is configured to acquire vehicle speed data. When the vehicle start switch 32 is turned on, the electric vehicle 100 can be driven by the inverter 12 and the motor generator 11, and the refrigerant pump 14 can be started by a command from the control unit 50. When the vehicle start switch 32 is turned off, the inverter 12 stops and the motor generator 11 cannot be driven, the refrigerant pump 14 also stops, and the electric vehicle 100 cannot be driven.

  When the vehicle start switch 32 is turned on and the electric vehicle 100 is started, the refrigerant pump 14 is also started, and the refrigerant is circulated through the refrigerant flow path 20 and the radiator 15 to cool the inverter 12 and the motor generator 11. In this case, the switching valves 16 and 18 are each switched to the radiator 15 side. In FIG. 1, the bypass pipe side of each switching valve 16, 18 is a black triangle and the radiator side is a white triangle because the valve body inside the switching valve 16, 18 is switched to the bypass pipe 30 side. Thus, no refrigerant flows through the bypass pipe 30 and all the refrigerant flows into the radiator 15. The refrigerant whose temperature has risen by absorbing heat from the inverter 12 and the motor generator 11 is cooled by the radiator 15 and circulates through the refrigerant flow path 20 as shown by the arrows in FIG.

  An operation in the case where the electric vehicle 100 configured as described above is turned on after the vehicle start switch 32 is turned off while traveling will be described with reference to the flowchart of FIG.

  As shown in step S101 of FIG. 2, while the electric vehicle 100 is traveling, the control unit 50 acquires the vehicle speed by the vehicle speed sensor 31 shown in FIG. 1, and as shown in step S102 of FIG. km / hr) is determined. Then, if the vehicle speed is 0 (km / hr) or higher, control unit 50 determines that electric vehicle 100 is traveling. Next, as shown in step S <b> 103 of FIG. 2, the control unit 50 determines whether or not the vehicle start switch 32 that is turned on (Ready on) during driving is turned off (Ready off). When the vehicle start switch 32 is on (Ready on), it waits until the vehicle start switch 32 is turned off (Ready off). When the vehicle start switch 32 is turned off (Ready off), the control unit 50 determines that the vehicle start switch 32 is turned off (Ready off) while the electric vehicle 100 is traveling, and FIG. It progresses to step S104 shown and waits until the vehicle start switch 32 is set to ON (Ready on). Then, as shown in step S104 of FIG. 2, when the vehicle start switch 32 is turned on (Ready on), the process proceeds to step S105 shown in FIG. 2, and a command for setting the switching valves 16 and 18 to the bypass side is output. In response to this command, the actuators 17 and 19 of the switching valves 16 and 18 operate to move the valve bodies provided therein to switch the internal flow path to the bypass pipe side. And the control part 50 starts the refrigerant | coolant pump 14 as shown to step S106 of FIG.

  In this way, when the refrigerant pump 14 is started with the switching valves 16 and 18 as bypass sides, the refrigerant does not pass through the radiator 15 but circulates through the refrigerant flow path 20 through the bypass pipe 30 as shown in FIG. . If the vehicle start switch 32 is turned off (Ready off) during traveling, the inverter 12 stays in the flow path inside the inverter 12 because the refrigerant flow stops when the temperature of the switching element is high. The temperature of the refrigerant is high. Moreover, even if the vehicle start switch 32 is turned off (Ready off), the electric vehicle 100 continues to travel with inertia. For this reason, the motor generator 11 is rotated by inertial running of the electric vehicle 100 and the motor generator 11 generates heat. This heat increases the temperature of the refrigerant staying in the flow path inside the motor generator 11. On the other hand, the inverter inlet pipe 21, the reservoir tank 13 between the inverter 12 and the motor generator 11, the reservoir tank inlet pipe 22, the refrigerant pump 14, the motor generator inlet pipe 24, the motor generator outlet pipe 25, and the bypass pipe 30 are retained. The temperature of the refrigerant that has been changed hardly from the state in which the vehicle start switch 32 is turned off (Ready off), and the temperature has risen like the refrigerant that has accumulated in the flow paths inside the inverter 12 and the motor generator 11. Absent. For this reason, when the refrigerant pump 14 is started and the radiator 15 is bypassed and the refrigerant is circulated as shown in FIG. 3, the high-temperature refrigerant accumulated in the flow paths inside the inverter 12 and the motor generator 11 and the other For example, in the reservoir tank 13, the pipes 21, 22, 23, 24, 25, and the bypass pipe 30 of the refrigerant flow path 20 are mixed with the refrigerant that has not been raised in temperature. Thus, the temperature of the entire refrigerant is made uniform. As a whole, the refrigerant temperature becomes slightly higher than the refrigerant temperature in a state where the vehicle start switch 32 is turned off (Ready off).

  Thus, a certain time is required until the refrigerant is mixed and reaches a uniform temperature. As shown in step S107 of FIG. 2, the controller 50 allows the refrigerant to flow only through the bypass pipe 30 for the first predetermined time and continues the operation without flowing the refrigerant through the radiator 15. The first predetermined time can be determined by the capacity of the radiator 15 or the discharge capacity of the refrigerant pump 14. Then, as shown in step S107 of FIG. 2, when the first predetermined time has elapsed, the control unit 50 issues a command to set each switching valve 16, 18 to an intermediate position, as shown in step S108 of FIG. Output. Here, the intermediate position means that the position of each valve body provided in the interior is a position where the refrigerant can flow through both the bypass pipe 30 and the radiator 15, as shown in FIG. The switching valves 16 and 18 can cause the refrigerant to flow through the bypass pipe 30 and the radiator 15. The flow rate ratio of the refrigerant between the bypass pipe 30 and the radiator 15 can be appropriately determined. For example, the flow quantity of the refrigerant flowing through each of the bypass pipe 30 and the radiator 15 may be made equal. The actuators 17 and 19 may be operated so that the flow rate of 15 is increased. In FIG. 4, the bypass pipe side and the radiator side of each switching valve 16, 18 are hatched because the valve body inside the switching valve 16, 18 is in an intermediate position, and refrigerant is present in both the bypass pipe 30 and the radiator 15. Is flowing.

  Then, as shown in step S109 in FIG. 2, the control unit 50 stands by until the second predetermined time elapses after the switching valves 16 and 18 are set to the intermediate positions. The second predetermined time is a time for replacing and mixing the temperature of the refrigerant in the radiator 15 with a refrigerant having a higher temperature in the refrigerant flow path 20 and the bypass pipe 30 that are gradually higher in temperature. 20, a time that may be appropriately determined depending on the capacity of the internal flow path of the inverter 12 and the motor generator 11, the flow rate of the refrigerant pump 14, and the like.

  Then, when the second predetermined time has elapsed, the control unit 50 switches the switching valves 16 and 18 to the radiator side as shown in step S110 of FIG. Then, as shown in FIG. 1, the refrigerant circulates through the inverter 12, the reservoir tank 13, the refrigerant pump 14, the motor generator 11, and the radiator 15, and the refrigerant whose temperature is increased by the inverter 12 and the motor generator 11 is cooled by the radiator 15. Then, it flows again into the inverter 12 and the motor generator 11.

  In the embodiment described above, when the vehicle start switch 32 is turned off during traveling and the vehicle is turned on after traveling or after the vehicle is stopped, the switching valve 16, so that the refrigerant flows bypassing the radiator 15. 18 is switched, it is possible to suppress the refrigerant that has accumulated in the inverter 12 and the motor generator 11 whose temperature has been increased due to residual heat or the like from flowing into the radiator 15 at a stretch. It can be mitigated and damage to the radiator 15 can be suppressed.

  Next, another operation of the electric vehicle 100 of the present invention will be described with reference to FIGS. In this operation, as shown in step S204 of FIG. 5, the control unit 50 starts the timer when the vehicle start switch 32 is turned off (Ready off) during traveling, and then the vehicle start switch 32 is turned on. When turned on (Ready on), the timer is stopped as shown in step S207 of FIG. 5, and the time from when the vehicle start switch 32 is turned off (Ready off) to when it is turned on (Ready on) is set. get. Further, the control unit 50 acquires the vehicle speed of the electrically powered vehicle 100 from the vehicle speed sensor 31 when the vehicle start switch 32 is turned off (Ready off) as shown in Step S <b> 205 of FIG. 5. Then, as shown in FIG. 6 and FIG. 7, when the time from turning off the vehicle start switch 32 to turning it on is long, or when the vehicle speed when turning off the vehicle start switch 32 is high, the control unit 50 Makes the first and second predetermined times longer. In this way, when the time from when the vehicle start switch 32 is turned off to when the vehicle start switch 32 is turned on is long, the refrigerant remaining in the respective internal flow paths due to the residual heat of the inverter 12 or the heat generation of the motor generator 11 Even if the temperature rise is large and it takes time to equalize the refrigerant temperature by flowing the refrigerant through the bypass pipe 30, the first and second times are lengthened. The thermal shock of can be suppressed. Further, when the electric vehicle 100 is traveling at a high speed, the residual heat of the inverter 12 and the heat generation of the motor generator 11 also increase when the vehicle start switch 32 is turned off. Since the time is lengthened, the thermal shock of the radiator 15 can be effectively suppressed.

  In the embodiment described above, the bypass pipe 30 has been described as being connected to the refrigerant flow path 20 via the two switching valves 16 and 18, but only the switching valve 18 on the upstream side of the refrigerant flow. The switching valve 16 on the downstream side of the refrigerant flow may not be provided. In this case, the same effects as those of the above-described embodiment can be obtained. The same is true if only the switching valve 16 on the downstream side of the refrigerant flow is provided.

  11 motor generator, 12 inverter, 13 reservoir tank, 14 refrigerant pump, 15 radiator, 15a radiator body, 15b radiator inlet pipe, 15c radiator outlet pipe, 16, 18 switching valve, 17, 19 actuator, 20 refrigerant flow path, 21 inverter Inlet pipe, 22 Reservoir tank inlet pipe, 23 Refrigerant pump inlet pipe, 24 Motor generator inlet pipe, 25 Motor generator outlet pipe, 30 Bypass pipe, 31 Vehicle speed sensor, 32 Vehicle start switch, 50 Control unit, 100 Electric vehicle.

Claims (6)

A common refrigerant flow path for allowing the refrigerant to flow through the driving motor and an electric power source that supplies electric power to the driving motor;
A cooler connected in series to the refrigerant flow path for cooling the refrigerant;
A bypass flow path that is connected to the refrigerant flow path in parallel with the cooler via a switching valve and bypasses the cooler;
A refrigerant pump provided in the refrigerant flow path;
A control unit for switching the switching valve and starting and stopping the refrigerant pump;
An electric vehicle comprising:
The controller is
A restart means for starting the refrigerant pump and switching the switching valve to the bypass flow path side when the vehicle start switch is turned on after being turned off during traveling;
An electric vehicle characterized by The electric vehicle according to claim 1,
The restarting means switches the switching valve to an intermediate position for flowing the refrigerant to the bypass flow path side and the cooler side after the first predetermined time has elapsed after starting of the refrigerant pump;
An electric vehicle characterized by The electric vehicle according to claim 2,
The restarting means switches the switching valve to the cooler side after a second predetermined time has elapsed after switching the switching valve to an intermediate position;
An electric vehicle characterized by An electric vehicle according to claim 2 or 3,
The restarting means changes the first and second predetermined times according to the time until the vehicle start switch is turned on after the vehicle start switch is turned off during traveling.
An electric vehicle characterized by The electric vehicle according to claim 4,
The restarting means increases the first and second predetermined times as the time until the vehicle start switch is turned on after the vehicle start switch is turned off during traveling is longer,
An electric vehicle characterized by The electric vehicle according to claim 4 or 5,
It has a vehicle speed sensor that detects the vehicle speed,
The restarting means of the control unit increases the first and second predetermined times as the vehicle speed detected by the vehicle speed sensor when the vehicle start switch is turned off increases.
An electric vehicle characterized by

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