JP4382584B2 - Cooling device and vehicle equipped with the same - Google Patents

Description

  The present invention relates to a cooling device and a vehicle equipped with the cooling device.

Conventionally, as this type of cooling device, a device that exchanges heat between cooling water that cools a fuel cell that is a power source mounted on a vehicle and a cooling refrigerant that cools the vehicle interior has been proposed (for example, , See Patent Document 1). The apparatus described in Patent Document 1 is configured to exchange heat between cooling water of a fuel cell and a cooling refrigerant, and a cooling refrigerant cooler for cooling the cooling water and a radiator that cools the cooling water. To save space.
Japanese Patent Laying-Open No. 2002-75389 (FIG. 10)

  However, in the cooling device described in Patent Document 1, even when the calorific value of the fuel cell becomes large, heat is always exchanged between the cooling water of the fuel cell and the cooling refrigerant, so that the cooling water Since it is warmed up, the load which cools a fuel cell may be large. On the other hand, since the cooling refrigerant is also heated by exchanging heat with the cooling water of the fuel cell, the cooling may not function sufficiently.

  This invention is made in view of such a subject, and provides the cooling device which can reduce the cooling load of a power source using the cooling capacity of the refrigerant | coolant for cooling, functioning cooling. One of the purposes. Another object is to provide a vehicle equipped with such a cooling device.

  The cooling device of the present invention employs the following means in order to achieve at least a part of the above object.

The cooling device of the present invention comprises:
A cooling device for cooling a power source,
A cooling refrigerant flow path through which the cooling refrigerant circulates;
A cooling refrigerant cooler connected to the cooling refrigerant flow path for cooling the cooling refrigerant;
Heat exchanging means for exchanging heat between the power source or a power refrigerant for cooling the power source and the cooling refrigerant;
Determining means for determining whether or not the cooling capacity of the cooling refrigerant cooler has sufficient capacity;
When it is determined by the determination means that there is a surplus in cooling capacity, the heat exchange means controls the heat source or the power refrigerant and the cooling refrigerant to exchange heat, and the determination means Heat exchange control means for controlling not to perform the heat exchange when it is determined that there is no surplus cooling capacity;
It is equipped with.

  In this cooling device, when the cooling capacity of the cooling refrigerant cooler has sufficient capacity, heat exchange is performed between the power source or the power refrigerant and the cooling refrigerant by the heat exchange means, and the cooling capacity of the cooling refrigerant cooler is increased. When there is no surplus power, heat exchange is not performed between the power source or the power refrigerant and the cooling refrigerant. Therefore, it is possible to reduce the cooling load of the power source by using the cooling capacity of the cooling refrigerant while functioning the cooling.

  The cooling device of the present invention includes a bypass flow path formed so that the cooling refrigerant flows from the cooling refrigerant cooler to the heat exchange means, and connected to the bypass flow path to the heat exchange means. Switching means for switching whether the cooling refrigerant flows or not to the heat exchange means, and the heat exchange control means controls the bypass flow path when performing the heat exchange. The switching means is controlled so that the cooling refrigerant flows through the cooling passage, and the switching means is controlled so that the cooling refrigerant does not flow through the bypass flow path when controlling not to perform the heat exchange. Good. By so doing, heat exchange can be performed between the power source or the power refrigerant and the cooling refrigerant with a relatively simple configuration.

  In the cooling device of the present invention, the bypass flow path may be formed so that the cooling refrigerant flows from the cooling refrigerant cooler to the cooling refrigerant cooler via the heat exchange means. By so doing, the cooling refrigerant warmed by the heat exchange means can be cooled again by the cooling refrigerant cooler, so that sufficient cooling capacity can be secured. At this time, the bypass flow path may be formed so that the cooling refrigerant flows from a predetermined position where the cooling capacity of the cooling refrigerant cooler has a surplus capacity to the vicinity of the predetermined position via the heat exchange means. Good.

  The cooling device according to the present invention includes a power coolant channel connected to the power source and configured to allow the power coolant to circulate, and the power coolant connected to the power coolant channel to dissipate heat by ventilation. And the heat exchange means may be disposed downstream of the power source and upstream of the radiator in the power coolant channel. In this way, since the power refrigerant is cooled by the radiator after being cooled by the cooling refrigerant, the cooling performance of the cooling refrigerant cooler is higher than that after the power refrigerant is cooled by the radiator and then cooled by the cooling refrigerant. Can be used effectively.

  The cooling device according to the present invention includes a power coolant channel connected to the power source and configured to allow the power coolant to circulate, and the power coolant connected to the power coolant channel to dissipate heat by ventilation. The cooling refrigerant cooler is disposed at a position where the ventilation passing through the radiator is not warmed, and the radiator is disposed at a position where the ventilation passing through the cooling refrigerant cooler is not warmed. Also good. In this way, compared with the configuration in which one of the radiator and the cooling refrigerant cooler warms the other ventilation, the air passing through the radiator is not heated by the cooling refrigerant cooler, and the cooling refrigerant Since the wind which tries to pass through the cooler is not warmed by the radiator, the heat radiation efficiency of the radiator and the cooling refrigerant cooler can be increased.

  The cooling device of the present invention includes a compressor that compresses and supplies the cooling refrigerant to the cooling refrigerant cooler, and the determination unit is configured to change the cooling refrigerant cooler based on an operating state of the compressor. It may be determined whether there is a surplus in the cooling capacity. Generally, in a cooling device, when the cooling capacity of the cooling refrigerant cooler is insufficient, the cooling capacity of the cooling refrigerant may be increased by compressing the cooling refrigerant with a compressor. Thus, since there is a correlation between the operating condition of the compressor and the cooling capacity of the cooling refrigerant cooler, it is determined whether or not the cooling capacity of the cooling refrigerant cooler has sufficient capacity depending on the operating condition of the compressor. Can be determined. Here, the “operating state of the compressor” includes, for example, the power consumption of the compressor, the work amount of the compressor (such as the number of rotations and the number of piston movements), and the pressure of the cooling refrigerant compressed by the compressor. May be.

  The cooling device of the present invention includes temperature detection means for detecting the temperature of the cooling refrigerant cooled by the cooling refrigerant cooler, and the determination means is the cooling refrigerant detected by the temperature detection means. It may be determined whether or not the cooling capacity of the cooling refrigerant cooler has sufficient capacity based on the temperature. In this way, since there is a correlation between the temperature of the cooling refrigerant cooled by the cooling refrigerant cooler and the cooling capacity of the cooling refrigerant cooler, the temperature of the cooling refrigerant cooler depends on the temperature of the cooling refrigerant. It can be determined whether or not the cooling capacity has a surplus. Here, the “temperature detection means” may be any device that can grasp the temperature of the cooling refrigerant. For example, the temperature detection means may directly determine the temperature of the cooling refrigerant, or may be the temperature of the cooling refrigerant cooler. Alternatively, the temperature of the cooling refrigerant may be obtained indirectly from the temperature of the cooling refrigerant flow path or the like. Further, it may be determined whether the cooling capacity of the cooling refrigerant cooler has sufficient capacity by regarding those temperatures as the temperature of the cooling refrigerant. At this time, the determination unit may determine that the cooling capacity of the cooling refrigerant cooler has sufficient capacity when the temperature of the cooling refrigerant detected by the temperature detection unit is in the vicinity of an outside air temperature. When the cooling refrigerant is sufficiently cooled by the outside air, the temperature becomes close to the outside air temperature. Therefore, it can be determined relatively easily that the cooling capacity of the cooling refrigerant cooler has sufficient capacity.

  The cooling device of the present invention further includes wind speed detecting means for detecting a wind speed of the air passing through the cooling refrigerant cooler, and the determination means is configured such that the wind speed detected by the wind speed detecting means is the cooling refrigerant cooling. It may be determined that the cooling capacity of the cooling refrigerant cooler has sufficient capacity when the cooling capacity of the cooling unit becomes equal to or higher than a predetermined speed. In this way, since the cooling refrigerant is cooled by the ventilation, there is a correlation between the value related to the ventilation speed and the cooling capacity of the cooling refrigerant cooler, so the wind speed of the ventilation that passes through the cooling refrigerant cooler. Thus, it can be determined whether or not the cooling capacity of the cooling refrigerant cooler has sufficient capacity. Here, the “wind speed detection means” may be any means that can grasp the wind speed of the ventilation passing through the cooling refrigerant cooler. For example, the “wind speed detection means” may directly determine the ventilation speed or may be mounted on the vehicle. If it is, the wind speed of the ventilation may be obtained indirectly from the vehicle speed or the like. Further, for example, it may be determined whether the cooling capacity of the cooling refrigerant cooler has sufficient capacity by regarding the vehicle speed or the like as the speed of ventilation passing through the cooling refrigerant cooler.

  In the cooling device of the present invention, the cooling refrigerant may be carbon dioxide. In this way, the degree of influence on global warming is small compared to using alternative chlorofluorocarbons (for example, HFC-134a).

  In the cooling device of the present invention, the power source may be a fuel cell that generates electric power by an electrochemical reaction. Since the fuel cell generates power by an electrochemical reaction, it is necessary to control the temperature within a certain temperature range. In particular, when a high output is required, the heat generated by the electrochemical reaction is increased, so that the cooling load is increased. Therefore, it is highly significant to apply the present invention to cooling of a fuel cell.

  The vehicle of the present invention is mounted with the cooling device according to any of the various aspects described above. Since the cooling device of the present invention can reduce the cooling load of the power source while functioning cooling, a vehicle equipped with the same also has the same effect.

  Next, the best mode for carrying out the present invention will be described using examples.

  Embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a block diagram of a vehicle 10 equipped with a fuel cell, and FIGS. 2 and 3 are block diagrams showing an outline of a cooling device 12. The fuel cell-equipped vehicle 10 generates a fuel cell 21 that generates electric power by an electrochemical reaction between hydrogen (fuel gas) supplied from a hydrogen cylinder 22 by a hydrogen pump 24 and oxygen in air (oxidized gas) supplied from an air compressor 26. (Refer to FIG. 2) A plurality of stacked fuel cell stacks 20 (corresponding to a power source of the present invention), a power storage device 34 capable of storing or discharging electric power, and driving wheels 18 and 18 driven by electric power The motor 35 includes a power control unit (PCU) 30 that controls the entire system, and a cooling device 12 that cools the fuel cell stack 20 and the cooling refrigerant.

  The fuel cell stack 20 has a stack structure in which a plurality of well-known solid polymer electrolyte fuel cells 21 are stacked, and functions as a high voltage power supply (several hundred volts). In each unit cell of the fuel cell stack 20, hydrogen gas is supplied from the hydrogen cylinder 22 to the anode after the pressure and flow rate are adjusted by the hydrogen pump 24, and compressed air whose pressure is adjusted is supplied from the air compressor 26 to the cathode. An electromotive force is generated by the progress of a predetermined electrochemical reaction. In this fuel cell stack 20, in order to exhibit high power generation efficiency, the fuel cell stack 20 must be controlled within a predetermined operating temperature range (for example, 70 to 80 ° C.). The surplus hydrogen that has not reacted is sent upstream of the hydrogen pump 24 and reused as fuel gas.

  The power storage device 34 has a structure in which a plurality of nickel metal hydride storage batteries are connected in series, and functions as a high-voltage power supply (several hundred volts). Under the control of the PCU 30, the power storage device 34 drives the drive motor 35 at the start of the vehicle, assists the drive motor 35 at the time of acceleration, and supplies power to other auxiliary machines. The power storage device 34 collects regenerative power from the drive motor 35 during deceleration regeneration or is charged by the fuel cell stack 20 according to the load. The power storage device 34 may be an electric double layer capacitor (capacitor) or the like.

  The drive motor 35 is a three-phase synchronous motor, and is arranged at the rear of the vehicle. The direct current output from the fuel cell stack 20 is converted into a three-phase alternating current by the PCU 30 and supplied to generate a rotational driving force. The driving force generated by the drive motor 35 is finally output to the drive wheels 18 and 18 via the drive shaft 14 and the differential gear 16 to cause the fuel cell vehicle 10 to travel. The vehicle speed v when the vehicle is traveling is detected by a vehicle speed sensor 37. The vehicle speed sensor 37 is electrically connected to the cooling controller 60.

  The PCU 30 includes a controller unit 31 configured as a logic circuit centered on a microcomputer, and an inverter unit 32 that converts a high voltage direct current of the fuel cell stack 20 and the power storage device 34 and an alternating current of the drive motors 34 and 34. And. The controller unit 31 of the PCU 30 supplies the electric power generated in the fuel cell stack 20 to the drive motor 35 and the power storage device 34 according to the load of the drive motor 35 and the power storage amount of the power storage device 34, and the power storage device 34. And the like. In addition, regenerative power obtained from the drive motor 35 is supplied to the power storage device 34 during deceleration or braking. The PCU 30 includes an input / output port (not shown), and various control signals from a cooling controller 60 described later are input to the controller unit 31 via the input port, and the controller unit 31 supplies the hydrogen pump 24 to the hydrogen pump 24. A drive signal, a drive signal to the air compressor 26, and the like are output via an output port.

  The cooling device 12 includes a fuel cell radiator 40 that dissipates cooling water (which corresponds to the power refrigerant of the present invention) that cools the fuel cell stack 20, a cooling refrigerant cooler 50 that cools the cooling refrigerant, and a fuel cell. And a cooling controller 60 for controlling cooling of the system.

  The fuel cell radiator 40 is disposed in front of the vehicle and dissipates heat by circulating cooling water circulating in the fuel cell 21. Connected to the fuel cell radiator 40 is a cooling water passage 41 for circulating cooling water from the fuel cell radiator 40 to the fuel cell radiator 40 via the inside of the fuel cell 21. The cooling water passage 41 is provided with a circulation pump 42, and the circulation water is circulated by the circulation pump 42 at a circulation speed of 50 to 150 L / min. Further, the cooling water flow path 41 is provided with a cooling water temperature sensor 36 at a position downstream of the outlet of the fuel cell stack 20 to detect the cooling water temperature Tf. The cooling water temperature sensor 36 is electrically connected to the cooling controller 60. Further, an outside air temperature sensor 39 that detects the outside air temperature Ta is provided in the vicinity of the fuel cell radiator 40. The outside air temperature sensor 39 is electrically connected to the cooling controller 60. A first cooling fan 46 is disposed downstream of the ventilation that passes through the fuel cell radiator 40. The first cooling fan 46 is a resin fan that forcibly vents the outside air to the fuel cell radiator 40 and is rotationally driven by a motor (not shown). The first cooling fan 46 is electrically connected to the cooling controller 60.

  The cooling refrigerant cooler 50 cools the high-temperature and high-pressure gaseous cooling refrigerant by ventilation. Here, carbon dioxide is used as the cooling refrigerant. The cooling refrigerant cooler 50 is disposed below the fuel cell radiator 40 in parallel with the fuel cell radiator 40 with respect to the flow of air passing through the fuel cell radiator 40. Therefore, the cooling refrigerant cooler 50 does not warm the ventilation that passes through the fuel cell radiator 40, and the fuel cell radiator 40 does not warm the ventilation that passes through the cooling refrigerant cooler 50. Although the cooling refrigerant is carbon dioxide, other alternative chlorofluorocarbons (HFC-134a, HC, etc.) may be used. The cooling refrigerant cooler 50 is connected to a cooling refrigerant flow path 51 through which the cooling refrigerant circulates. A pressure reducing valve 52, an evaporator 53, and a compressor 54 are connected to the cooling refrigerant flow path 51 downstream of the cooling refrigerant cooler 50. A second cooling fan 56 is disposed downstream of the ventilation passing through the cooling refrigerant cooler 50. The second cooling fan 56 is a resin fan that forcibly vents outside air to the cooling refrigerant cooler 50 and is rotationally driven by a motor (not shown). The second cooling fan 56 is electrically connected to the cooling controller 60. The second cooling fan 56 is controlled by the cooling controller 60 so that the rotational speed of the fan increases as the vehicle speed v decreases because the traveling wind decreases and a forced ventilation amount is required when the vehicle speed v is low. The Further, since the required heat radiation amount of the cooling refrigerant increases as the pressure of the cooling refrigerant increases, the cooling controller 60 controls the rotational speed to increase as the pressure of the cooling refrigerant increases.

  The pressure reducing valve 52 is a valve that reduces the temperature of the cooling refrigerant cooled by the cooling refrigerant cooler 50 to low temperature and low pressure.

  The evaporator 53 is configured such that wind from a blower fan (not shown) passes through the evaporator 53, and cools the wind passing through the evaporator 53 with the cooling refrigerant that has been cooled to low temperature and low pressure by the pressure reducing valve 52.

  The compressor 54 is a scroll-type electric inverter compressor that compresses the cooling refrigerant warmed by the evaporator 53 with electric power supplied from the PCU 30 and converts the refrigerant into a high-temperature and high-pressure gas. Here, if the cooling refrigerant warmed by the evaporator 53 is compressed into a high-pressure gas, it becomes easier to cool by the cooling refrigerant cooler 50 and the cooling capacity is increased. Therefore, the compressor 54 is supplied with air that passes through the evaporator 53. The cooling controller 60 controls the scroll rotation speed to increase as the cooling amount increases. As described above, the cooling refrigerant circulates through the cooling refrigerant cooler 50, the pressure reducing valve 52, the evaporator 53, and the compressor 54, thereby cooling the wind generated by the blower fan (not shown). Cooling is performed by supplying.

  Further, a bypass flow path 61 is connected to the cooling refrigerant cooler 50. This bypass flow path 61 allows cooling refrigerant to flow from a bypass inlet 50a (see FIG. 2) located near the center of the cooling refrigerant cooler 50 to a bypass outlet 50b located near the bypass inlet via a heat exchanger 62. It is formed to circulate. The position of the bypass inlet 50a is obtained by empirically obtaining in advance the temperature of the cooling refrigerant in the cooling refrigerant cooler 50 when the cooling load state is changed, and the cooling refrigerant cooler 50 under certain operating conditions. The temperature of the internal cooling refrigerant is determined as a position near the outside air temperature. At this position, the cooling refrigerant is cooled until it can no longer be cooled under certain operating conditions, so that sufficient capacity can be generated in the cooling capacity of the cooling refrigerant cooler 50. On the other hand, the position of the bypass outlet 50b is determined as a position where the cooling refrigerant warmed by the heat exchanger flows and can be sufficiently cooled to the outlet of the cooling refrigerant cooler 50. A cooling refrigerant temperature sensor 38 is provided in the vicinity of the bypass inlet 50a, and a cooling refrigerant temperature Tc in the vicinity of the bypass inlet 50a is detected. The cooling refrigerant temperature sensor 38 is electrically connected to the cooling controller 60. A switching valve 64 is disposed in the bypass passage 61 in the vicinity of the bypass inlet 50a and the bypass outlet 50b of the cooling refrigerant cooler 50. The switching valve 62 is a four-way valve that switches whether the cooling refrigerant flows through the heat exchanger 62 or does not flow through the heat exchanger 62, and is electrically connected to the cooling controller 60. . The cooling refrigerant cooler 50 is partitioned between the bypass inlet 50a and the bypass outlet 50b, and the cooling refrigerant flows through the switching valve 64 (see FIG. 2).

  The heat exchanger 62 performs heat exchange between the cooling water and the cooling refrigerant, and is disposed between the cooling water channel 41 and the bypass channel 61. The heat exchanger 62 is disposed downstream of the fuel cell stack 20 and upstream of the fuel cell radiator 40. In the heat exchanger 62, heat exchange is performed by using cooling water and a cooling refrigerant as counterflows (see FIG. 3).

  The cooling controller 60 is a controller constituted by a CPU, a ROM, and a RAM, and controls the cooling of the fuel cell stack 20. The cooling controller 60 includes an input / output port (not shown), and includes a signal from the cooling water temperature sensor 36, a signal from the vehicle speed sensor 37, a signal from the cooling refrigerant temperature sensor 38, and a signal from the outside air temperature sensor 39. Etc. are input via the input port, the drive signal to the switching valve 64, the drive signal to the first cooling fan 46, the drive signal to the compressor 54, the drive signal to the second cooling fan 56, to the switch valve 64 Is output via the output port. The cooling controller 60 is connected to the PCU 30 via this input / output port, and exchanges various control signals and data. The cooling controller 60 corresponds to the determination unit and the heat exchange control unit of the present invention.

  Next, the operation of the fuel cell-equipped vehicle 10 of this embodiment configured as described above, first, the operation of cooling the fuel cell stack 20 will be described. When the fuel cell vehicle 10 is started, a fuel cell cooling routine shown in FIG. 4 is started. This routine is stored in the ROM (not shown) of the cooling controller 60, and is repeatedly executed at a predetermined timing (for example, every several milliseconds) by the CPU (not shown) of the cooling controller 60. When the fuel cell vehicle 10 is started, the switching valve 64 is switched so that the cooling refrigerant does not flow through the heat exchanger 62, as shown in FIG. First, the cooling controller 60 acquires the cooling water temperature Tf and the vehicle speed v of the vehicle (step S100), and determines whether or not the cooling water temperature Tf is below a predetermined operating temperature range (for example, 70 to 80 ° C.) ( Step S110). When the cooling water temperature Tf is not below the predetermined operating temperature range, the cooling controller 60 sets the voltage V for rotating the first cooling fan 46 based on the cooling water temperature Tf and the vehicle speed v (step S120), and the set voltage The first cooling fan 46 is rotationally driven at V (step S130), and this routine is finished. Here, the voltage V is set using a cooling map that is set so that the voltage increases as the coolant temperature Tf and the vehicle speed v increase, and is stored in the ROM. That is, the amount of air passing through the fuel cell radiator 40 is set to be large when the heat generation of the fuel cell stack 20 is large. On the other hand, when the cooling water temperature Tf is equal to or lower than the predetermined operating temperature range, the cooling controller 60 allows the cooling water provided in the cooling water passage 41 to pass through the fuel cell radiator 40 so as not to cool the cooling water. The valve (not shown) is switched so as to circulate the cooling water in a bypass flow path (not shown) that can be avoided (step S140), and this routine is finished.

  Next, an operation for exchanging heat between the cooling water and the cooling refrigerant will be described. FIG. 5 is a flowchart of a heat exchange control routine executed by the CPU of the cooling controller 60. This routine is stored in a ROM (not shown) of the cooling controller 60, and is repeatedly executed at a predetermined timing (for example, every several milliseconds) by the cooling controller 60 when a cooling switch (not shown) is turned on. The

  When this routine is started, the cooling controller 60 first determines the cooling water temperature Tf, the cooling refrigerant temperature Tc, and the outside air temperature Ta from the cooling water temperature sensor 36, the cooling refrigerant temperature sensor 38, and the outside air temperature sensor 39. Each is acquired (step S300). Next, the cooling controller 60 determines whether or not the cooling water temperature Tf is equal to or higher than a predetermined operating temperature range (for example, 70 to 80 ° C.) (step S310). As described above, the cooling device 12 controls the cooling so that the temperature of the fuel cell stack 20 falls within a predetermined operating temperature range. However, when the high-speed traveling continues, the amount of heat generated by the fuel cell stack 20 is the fuel. If the state of exceeding the heat dissipation amount of the battery radiator 40 continues, the cooling water temperature Tf may exceed a predetermined operating temperature range. When the cooling water temperature Tf is equal to or higher than the predetermined operating temperature range, the cooling controller 60 determines whether or not the cooling refrigerant temperature Tc is near the outside air temperature Ta (for example, the outside air temperature + 5 ° C. or less). Step S320). When the cooling refrigerant temperature Tc is near the outside air temperature, the cooling controller 60 considers that the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity, and switches the cooling refrigerant to flow through the heat exchanger 62. The valve 64 is switched (step S330), and this routine is finished. Before the switching valve 64 is switched, the cooling refrigerant cooled to the bypass inlet 52a immediately returns to the cooling refrigerant cooler 50 through the bypass outlet 52b via the switching valve 64 as shown in FIG. However, when the switching valve 64 is switched, the cooling refrigerant cooled to the bypass inlet 52a flows through the heat exchanger 62 via the switching valve 64 as shown in FIG. Then, heat exchange is performed between the cooling refrigerant cooled to the vicinity of the outside air temperature (for example, 35 ° C.) and the cooling water (for example, 85 ° C.) exceeding the predetermined operating temperature range. The cooling water cooled by the cooling refrigerant is further cooled to an appropriate temperature by the fuel cell radiator 40 and flows through the fuel cell stack 20 to cool it. On the other hand, the cooling refrigerant warmed by the cooling water returns to the cooling refrigerant cooler 50 from the bypass outlet 50b and is cooled again, and cools the wind by a blower fan (not shown) by the evaporator 53 via the pressure reducing valve 52. To work.

  On the other hand, when the cooling water temperature Tf is less than the predetermined operating temperature range in step S310, it is not necessary to use the cooling capacity of the cooling refrigerant cooler 50, or in step S320, the cooling refrigerant temperature Tc is near the outside air temperature. If not, the cooling capacity of the cooling refrigerant cooler 50 is not sufficient, so the cooling controller 60 switches the switching valve 64 so that the cooling refrigerant does not flow to the heat exchanger 62 (step S340). finish. Even when heat is exchanged in the heat exchanger 62 and the temperature of the cooling refrigerant rises too much, the cooling refrigerant circulates and the temperature detected by the cooling refrigerant temperature sensor 38 also rises. Since it is determined that the cooling capacity of the refrigerant cooler 50 has no surplus capacity and heat exchange is not performed, the cooling can be functioned.

  According to the fuel cell-equipped vehicle 10 equipped with the cooling device 12 of the present embodiment described in detail above, the cooling water that cools the fuel cell 21 by the heat exchanger 62 when the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity. Is exchanged between the cooling water and the cooling refrigerant, and when the cooling capacity of the cooling refrigerant cooler 50 is not sufficient, heat exchange is not performed between the cooling water for cooling the fuel cell 21 and the cooling refrigerant. Therefore, the cooling load of the fuel cell stack 20 can be reduced using the cooling capacity of the cooling refrigerant while the cooling is functioning.

  In addition, the cooling controller 60 controls the switching valve 64 so that the cooling refrigerant flows through the bypass passage 61 when performing control so as to perform heat exchange, and bypass passage when performing control so as not to perform heat exchange. Since the switching valve 64 is controlled so that the cooling refrigerant does not flow through 61, heat exchange can be performed between the cooling water and the cooling refrigerant with a relatively simple configuration.

  Further, the bypass flow path 61 is formed so that the cooling refrigerant flows from the bypass inlet 50a where the cooling capacity of the cooling refrigerant cooler 50 has a surplus to the bypass outlet 50b via the heat exchanger 62. The cooling refrigerant to which heat is given by the heat exchanger 62 can be sent to the bypass outlet 50b where the cooling capacity has a surplus, and can be cooled again by the cooling refrigerant cooler 50, and sufficient cooling capacity can be secured.

  Furthermore, since the heat exchanger 62 is disposed in the cooling water channel 41 downstream of the fuel cell stack 20 and upstream of the fuel cell radiator 40, the fuel cell is cooled after the cooling water is cooled by the cooling refrigerant. Since it is cooled by the radiator 40, the cooling performance of the cooling refrigerant cooler 50 can be used more effectively than the cooling water is cooled by the cooling refrigerant after being cooled by the fuel cell radiator 40. Further, in the fuel cell radiator 40, since the temperature control of the cooling water is performed by the first cooling fan 46 or the like so as to be in a predetermined operation temperature range, the fuel cell radiator 40 is cooled by the cooling refrigerant after being cooled by the fuel cell radiator 40. This configuration has better temperature controllability.

  The cooling refrigerant cooler 50 is disposed at a position where the ventilation passing through the fuel cell radiator 40 is not warmed, and the fuel cell radiator 40 is disposed at a position where the ventilation passing through the cooling refrigerant cooler 50 is not warmed. Therefore, compared with the configuration in which one of the fuel cell radiator 40 and the cooling refrigerant cooler 50 warms the other ventilation, the wind that is about to pass through the fuel cell radiator 40 is not heated by the cooling refrigerant cooler 50. In addition, since the air that attempts to pass through the cooling refrigerant cooler 50 is not heated by the fuel cell radiator 40, the heat radiation efficiency of the fuel cell radiator 40 and the cooling refrigerant cooler 50 can be increased. Further, since the heat radiation efficiency of the fuel cell radiator 40 and the cooling refrigerant cooler 50 is increased, the fuel cell radiator 40 and the cooling refrigerant cooler 50 can be made compact.

  In addition, since there is a correlation between the temperature of the cooling refrigerant cooled by the cooling refrigerant cooler 50 and the cooling capacity of the cooling refrigerant cooler 50, the cooling controller 60 determines the cooling refrigerant temperature Tc. Based on the above, it is possible to determine whether or not the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity. In addition, when the cooling refrigerant is sufficiently cooled by the outside air, the temperature becomes close to the outside air temperature. Therefore, the cooling controller 60 can relatively easily cool the air depending on whether or not the cooling refrigerant temperature Tc is near the outside air temperature. It can be determined that the cooling capacity of the refrigerant cooler 50 has sufficient capacity.

  Furthermore, since the cooling refrigerant is carbon dioxide, the degree of influence on global warming is small compared to using an alternative chlorofluorocarbon (for example, HFC-134a).

  Furthermore, the power source of the fuel cell vehicle 10 of the invention is a fuel cell stack 21 in which a plurality of fuel cells 21 that generate electricity by electrochemical reaction are stacked. Since the fuel cell 21 generates electric power by an electrochemical reaction, it is necessary to control its temperature within a certain temperature range. In particular, when a high output is required, the heat generated by the electrochemical reaction increases, so the cooling load increases. Therefore, it is highly significant that the present invention is applied to the cooling of the fuel cell stack 21.

  Further, in the heat exchanger 62, since the cooling water and the cooling refrigerant perform heat exchange in a counterflow, compared to the case where heat exchange is performed by a parallel flow in which the cooling water and the cooling refrigerant circulate in the same direction, Exchange efficiency is good.

  The fuel cell 21 mounted on the fuel cell-equipped vehicle 10 has a large load on the fuel cell 21 and a large amount of heat generated by the fuel cell 21 during high-speed travel where a large vehicle driving force is required. The amount of heat increases. On the other hand, there is no great difference in the necessity of cooling the cooling refrigerant 50 during cooling at high speed or low speed. In addition, since the amount of air passing through the cooling refrigerant cooler 50 increases during high-speed traveling, there is a tendency for the remaining cooling capacity of the cooling refrigerant cooler 50 to be generated. As described above, in the fuel cell-equipped vehicle 10, when the amount of heat generated by the fuel cell 21 increases, there is a surplus in the cooling performance of the cooling refrigerant cooler 50. It is easy to reduce.

  In addition, this invention is not limited to the Example mentioned above at all, and as long as it belongs to the technical scope of this invention, it cannot be overemphasized that it can implement with a various aspect.

  For example, in the above-described embodiment, it is determined whether the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity based on the cooling refrigerant temperature Tc detected by the cooling refrigerant sensor 38 by the cooling controller 60. However, based on the rotation speed of the compressor 54, it may be determined whether there is sufficient capacity in the cooling capacity of the cooling refrigerant cooler. Generally, when the cooling capacity of the cooling refrigerant cooler 50 is insufficient, the cooling refrigerant may be compressed by the compressor 54 to increase the cooling capacity. Therefore, the rotation speed of the compressor 54 and the cooling refrigerant cooler Since there is a correlation with the cooling capacity of 50, it is possible to determine whether or not the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity based on the rotation speed of the compressor 54. Instead of the rotational speed of the compressor 54, for example, the power consumption of the compressor 54, the pressure of the cooling refrigerant compressed by the compressor 54, or the number of piston movements when a piston type compressor is used. Also good.

  Alternatively, a wind speed sensor for detecting the speed of the wind passing through the cooling refrigerant cooler is provided, and the wind speed detected by the wind speed sensor is equal to or higher than a predetermined speed at which the cooling capacity of the cooling refrigerant cooler 50 has a surplus. Sometimes, it may be determined that the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity. In this way, since the cooling refrigerant is cooled by the ventilation, there is a correlation between the value relating to the wind speed and the cooling capacity of the cooling refrigerant cooler, so that the cooling speed depends on the speed of the wind passing through the cooling refrigerant cooler. It can be determined whether the cooling capacity of the refrigerant cooler 50 has sufficient capacity. Here, the predetermined speed has previously experienced the temperature of the cooling refrigerant at the bypass inlet 50a of the cooling refrigerant cooler 50 when the speed of the wind passing through the cooling refrigerant cooler 50 or the load state of the cooling is changed. Therefore, it may be determined as a wind speed at which the temperature of the cooling refrigerant at the bypass inlet 50a is close to the outside air temperature. Note that the wind speed of the ventilation may be obtained indirectly by using a vehicle speed sensor or the like instead of the wind speed sensor, or the vehicle speed may be regarded as the wind speed.

  Further, in the above-described embodiment, the switching valve 64 is provided in the bypass flow path 61 connected to the cooling refrigerant cooler 50 to switch whether the cooling refrigerant is allowed to flow to the heat exchanger 62 and to exchange heat of the cooling water. However, as in the cooling device 112 shown in FIG. 6, a switching valve 64 is provided in the bypass flow path 161 connected to the cooling water flow path 41 so that the cooling water flows to the heat exchanger 62. The cooling refrigerant may be switched to be allowed to flow, and the cooling refrigerant may be circulated through the heat exchanger 62 at all times. Even in this case, the cooling load of the fuel cell stack 20 can be reduced while the cooling is functioning.

  Further, in the above-described embodiment, the cooling water flowing through the cooling water flow path 41 and the cooling refrigerant flowing through the bypass flow path 61 exchange heat in the heat exchanger 62. The bypass channel 61 may be formed so as to be provided alongside the water channel 41, and heat exchange may be performed directly between the fuel cell stack 20 and the cooling refrigerant. Alternatively, a water jacket portion that covers the outer periphery of the fuel cell stack 20 is formed, and a bypass flow path 61 is connected to the water jacket portion to circulate the cooling refrigerant, so that the fuel cell stack 20 and the cooling refrigerant are directly connected. Heat exchange may be performed at Even in this case, the same effect as the present invention can be obtained.

  Furthermore, in the above-described embodiment, the cooling refrigerant cooler 50 is arranged in parallel with the fuel cell radiator 40 with respect to the flow of air passing through the fuel cell radiator 40 below the fuel cell radiator 40. A cooling refrigerant cooler 50 may be disposed in front of the battery radiator 40 in series with the fuel cell radiator 40 with respect to the flow of air passing through the fuel cell radiator 40. In this way, the cooling of the fuel cell stack 20 can be reduced by using the cooling capacity of the cooling refrigerant while functioning the cooling while reducing the size of the cooling refrigerant cooler 50 and the fuel cell radiator 40 in parallel. Can be reduced.

  In the embodiment described above, the temperature of the cooling refrigerant is directly detected by the cooling refrigerant temperature sensor. However, the cooling refrigerant is indirectly detected from the temperature of the cooling refrigerant cooler 50 and the temperature of the cooling refrigerant flow path 51. The temperature may be obtained. Further, these temperatures may be regarded as the temperature of the cooling refrigerant to determine whether or not the cooling capacity of the cooling refrigerant cooler 50 has sufficient capacity.

  In the above-described embodiment, the switching valve 64 switches whether or not the cooling refrigerant flows through the heat exchanger 62. However, as in the cooling device 212 shown in FIG. The flow rate control valves 264a and 264b are provided in the flow path 61a and the heat exchange flow path 61b, respectively, a check valve 264c is provided so that the cooling refrigerant does not flow backward, and an outlet temperature sensor 238 is provided near the outlet of the cooling refrigerant cooler 50. The flow rate is controlled so that the flow rate of the cooling refrigerant flowing through the heat exchanger 62 decreases as the temperature of the cooling refrigerant in the vicinity of the outlet of the cooling refrigerant cooler 50 detected by the outlet temperature sensor 238 increases. You may control by valve | bulb 264a, 264b. By doing so, it is possible to reduce the cooling load of the fuel cell stack 20 while allowing the cooling to function more accurately. Further, the flow rate of the cooling refrigerant flowing through the heat exchanger 62 may be controlled based on the cooling water temperature Tf, the cooling refrigerant temperature Tc, or the like.

  Further, in the above-described embodiment, whether or not the cooling capacity of the cooling refrigerant cooler 50 is used based on whether or not the cooling water temperature Tf is equal to or higher than a predetermined operating temperature range (for example, 70 to 80 ° C.). Although it determined, you may determine based on whether it is more than predetermined temperature (for example, 75 degreeC etc.). Even in this case, it is possible to reduce the cooling load of the fuel cell stack 20 by using the cooling capacity of the cooling refrigerant while functioning the cooling.

  Furthermore, in the above-described embodiment, the power source of the vehicle is the fuel cell stack 20, but any power source that requires cooling may be used, for example, the driving motor 35, an engine, a battery, or the like. There may be.

  Furthermore, in the above-described embodiment, the cooling device 12 is applied to the fuel cell vehicle 10 (automobile). However, the cooling device 12 is not particularly limited as long as the fuel cell radiator 40 and the cooling refrigerant cooler 50 are provided. You may apply to a ship, an aircraft, etc., and may apply to the electric power generation system of a house, etc.

It is a block diagram which shows the outline of a structure of the fuel cell mounting vehicle 10 of a present Example. It is explanatory drawing of the cooling device 12 of a present Example. It is explanatory drawing of the cooling device 12 of a present Example. It is a fuel cell cooling control routine of a present Example. It is a heat exchange control routine of a present Example. FIG. 2 is a configuration diagram showing an outline of a configuration of a cooling device 112. FIG. 2 is a configuration diagram showing an outline of the configuration of a cooling device 212.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 10 Fuel cell vehicle, 12 Cooling device, 14 Drive shaft, 16 Differential gear, 17 Drive wheel, 18 Drive wheel, 20 Fuel cell stack, 21 Fuel cell, 22 Hydrogen cylinder, 24 Hydrogen pump, 26 Air compressor, 30 PCU, 31 controller section, 32 inverter section, 34 power storage device, 35 driving motor, 36 cooling water temperature sensor, 37 vehicle speed sensor, 38 cooling refrigerant temperature sensor, 39 outside air temperature sensor, 40 fuel cell radiator, 41 cooling water flow path, 42 circulation Pump, 46 First cooling fan, 50 Cooling refrigerant cooler, 50a Bypass inlet, 50b Bypass outlet, 51 Cooling refrigerant flow path, 52 Pressure reducing valve, 53 Evaporator, 54 Compressor, 56 Second cooling fan, 60 For cooling Controller, 61 bypass flow path, 61a bypass Road, 61b heat exchange passage, 62 a heat exchanger, 64 a switching valve, 112 cooler, 161 bypass passage, 212 cooling apparatus, 238 an outlet temperature sensor, 264a, 264b flow control valve, 264c check valve.

Claims (13)

A cooling device for cooling a power source,
A cooling refrigerant flow path through which the cooling refrigerant circulates;
A cooling refrigerant cooler connected to the cooling refrigerant flow path for cooling the cooling refrigerant;
Heat exchanging means for exchanging heat between the power source or a power refrigerant for cooling the power source and the cooling refrigerant;
Determining means for determining whether or not the cooling capacity of the cooling refrigerant cooler has sufficient capacity;
When it is determined by the determination means that there is sufficient cooling capacity, the heat exchange means controls the heat source or the power refrigerant and the cooling refrigerant to exchange heat, and the determination means Heat exchange control means for controlling not to perform the heat exchange when it is determined that there is no surplus cooling capacity;
With cooling device. The cooling device according to claim 1,
A bypass passage formed so that the cooling refrigerant flows from the cooling refrigerant cooler to the heat exchange means;
Switching means connected to the bypass flow path for switching whether the cooling refrigerant circulates in the heat exchange means or whether the cooling refrigerant does not circulate in the heat exchange means;
With
The heat exchange control means controls the switching means so that the cooling refrigerant flows through the bypass flow path when performing control to perform the heat exchange, and controls the heat exchange not to perform the heat exchange. Controlling the switching means so that the cooling refrigerant does not flow through the bypass flow path;
Cooling system. The bypass flow path is formed such that the cooling refrigerant flows from the cooling refrigerant cooler to the cooling refrigerant cooler via the heat exchange means.
The cooling device according to claim 2. The bypass flow path is formed such that the cooling refrigerant flows from a predetermined position where a surplus capacity is generated in the cooling capacity of the cooling refrigerant cooler to the vicinity of the predetermined position via the heat exchange means.
The cooling device according to claim 3. The cooling device according to any one of claims 1 to 4,
A power refrigerant flow path connected to the power source and formed so that the power refrigerant flows;
A radiator connected to the power refrigerant flow path and dissipating heat by passing the power refrigerant;
With
The heat exchanging means is disposed downstream of the power source and upstream of the radiator in the power coolant channel.
Cooling system. The cooling device according to any one of claims 1 to 5,
A power refrigerant flow path connected to the power source and formed so that the power refrigerant flows;
A radiator connected to the power refrigerant flow path and dissipating heat by passing the power refrigerant;
With
The cooling refrigerant cooler is disposed at a position where the ventilation passing through the radiator is not warmed, and the radiator is disposed at a position where the ventilation passing through the cooling refrigerant cooler is not warmed.
Cooling system. The cooling device according to any one of claims 1 to 6,
A compressor that compresses and supplies the cooling refrigerant to the cooling refrigerant cooler;
The determination means determines whether or not there is a surplus in the cooling capacity of the cooling refrigerant cooler based on the operating state of the compressor.
Cooling system. The cooling device according to any one of claims 1 to 7,
Temperature detecting means for detecting the temperature of the cooling refrigerant cooled by the cooling refrigerant cooler,
The determination means determines whether or not there is a surplus in the cooling capacity of the cooling refrigerant cooler based on the temperature of the cooling refrigerant detected by the temperature detection means;
Cooling system. The determination means determines that the cooling capacity of the cooling refrigerant cooler has sufficient capacity when the temperature of the cooling refrigerant detected by the temperature detection means is in the vicinity of an outside air temperature.
The cooling device according to claim 8. The cooling device according to any one of claims 1 to 9,
A wind speed detecting means for detecting a wind speed of the ventilation passing through the cooling refrigerant cooler,
The determination means has a surplus capacity in the cooling capacity of the cooling refrigerant cooler when the wind speed detected by the wind speed detection means exceeds a predetermined speed at which a surplus capacity is generated in the cooling capacity of the cooling refrigerant cooler. To determine,
Cooling system.   The cooling device according to claim 1, wherein the cooling refrigerant is carbon dioxide.   The cooling device according to claim 1, wherein the power source is a fuel cell that generates electric power by an electrochemical reaction.   A vehicle equipped with the cooling device according to claim 1.

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