JP2010277816A - Cooling system for fuel-cell loading vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a technique for unifying the cooling system of a fuel cell and the cooling system of an electric driving system, and making a cooling medium circulate through both the cooling systems using identical same pump. <P>SOLUTION: Cooling water from a first radiator and a second radiator connected in series is branched into two at a branching point 106, one of them is supplied from an electric driving system 107 to a fuel cell 111, and the other is supplied from a flow volume distribution control valve 108 to the fuel cell 111. Cooling water cooled at the radiator is supplied to the electric driving system 107, and the cooling water cooled at the radiator and the cooling water, removing the heat from the electric driving system 107, after being cooled at the radiator are mixed and supplied to the fuel cell. As a result, circulation of cooling water necessary for cooling both the electric driving system 107 required for relatively retaining at a low temperature and the fuel cell 111 required for retaining at high temperature relatively can be carried out using a single pump 110. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a cooling system for a vehicle equipped with a fuel cell, and more particularly to a technique for simplifying the system.

  As a technique related to cooling of a fuel cell in a vehicle equipped with a fuel cell, techniques described in, for example, Patent Document 1 and Patent Document 2 are known. A fuel cell generates heat during power generation, but its temperature needs to be controlled. Also, cooling of the electric drive system is necessary to avoid overheating of the motor and thermal destruction of the semiconductor device of the drive circuit that drives the motor.

  The appropriate cooling temperatures for the fuel cell and the electric drive system are different. For example, it is appropriate for a certain polymer electrolyte fuel cell to maintain a temperature of about 95 ° C. from the viewpoint of power generation efficiency. On the other hand, the semiconductor device needs to be kept at about 70 ° C. or lower in order to prevent thermal destruction and thermal runaway. For this reason, in the conventional in-vehicle cooling system, the cooling system for the fuel cell and the cooling system for the electric drive system are separate systems and have two cooling systems.

  FIG. 6 is a block diagram showing an outline of a cooling system for a vehicle equipped with a fuel cell according to the prior art. FIG. 6 shows a cooling system 500 mounted on a vehicle. In FIG. 6, the upper side of the figure is the front of the vehicle. The cooling system 500 includes a fuel cell radiator 501. The fuel cell radiator 501 air-cools the cooling water. The air-cooled cooling water is caused to flow through the circulation path 503 by the pump 502 and supplied to the fuel cell 504. The cooling water that has taken heat (reaction heat) from the fuel cell 504 is returned to the fuel cell radiator 501 where it is cooled again.

  In the cooling system of the fuel cell 508, the output of the pump 502 is adjusted so that the temperature of the cooling water in the portion discharged from the fuel cell 504 is, for example, 95 ° C.

  On the other hand, the cooling system 500 includes an electric drive system radiator 505. The electric drive system radiator 505 air-cools the cooling water, and the air-cooled cooling water flows through the circulation path 507 by the pump 506 and is supplied to the electric drive system 508. The electric drive system 508 includes, for example, a motor that generates a driving force, a semiconductor device of a drive circuit that drives the motor, and the like, which are cooled by cooling water. The cooling water that has cooled the electric drive system is returned to the electric drive system radiator 505, where it is cooled again.

  In the cooling system of the electric drive system 508, the output of the pump 506 is adjusted so that the temperature of the cooling water in the portion discharged from the electric drive system 508 is, for example, 70 ° C.

JP 2000-315513 A JP 2002-141079 A

  The cooling system shown in FIG. 6 requires a pump (502, 506) for the fuel cell and the electric drive system, and the configuration becomes complicated. In addition, power for two pumps is required. This becomes an obstacle when it is applied to a system that requires miniaturization, weight reduction, low energy consumption, and low cost like a passenger car.

  Therefore, an object of the present invention is to provide a technique for integrating a cooling system of a fuel cell and a cooling system of an electric drive system and circulating a cooling medium through both cooling systems using the same pump.

  The invention according to claim 1 is a vehicle equipped with a fuel cell and capable of traveling by electric drive, and a plurality of radiators extending in a width direction of the vehicle, and a downstream side of a flow of refrigerant from the plurality of radiators. An electric drive system element to be cooled, a fuel cell cooled by a refrigerant after cooling the electric drive system element, and a refrigerant pump for supplying a flow to the refrigerant are provided. This is a cooling system for a fuel cell vehicle.

  According to the first aspect of the present invention, the maintenance temperature may be relatively increased by the refrigerant after cooling the electric drive system that is the cooling target that needs to have a relatively low maintenance temperature. Therefore, even if there is only one refrigerant pump, a cooling balance can be ensured. In other words, two cooling systems having different cooling temperatures can be operated by a single refrigerant pump.

  The elements of the electric drive system are elements that constitute a system that performs electric drive. Specifically, the motor for moving the vehicle, the drive circuit for driving the motor, the drive Examples thereof include an electronic device constituting the circuit, a power supply circuit for supplying power to the drive circuit, and an electronic device constituting the power supply circuit. This element may be one or plural.

  According to a second aspect of the present invention, in the first aspect of the present invention, the plurality of radiators are arranged in multiple stages along the direction of air flow as the vehicle moves forward. According to the second aspect of the present invention, it is possible to cool the refrigerant by effectively using the limited internal space of the vehicle.

  According to a third aspect of the present invention, in the first or second aspect of the present invention, a branch for dividing the flow of the refrigerant disposed on the upstream side of the element of the electric drive system and a refrigerant separated from the branch are arranged. A flow rate ratio for adjusting a flow rate ratio between a refrigerant bypass flow path that bypasses the elements of the electric drive system and merges with the refrigerant that has cooled the elements of the electric drive system on the downstream side, and two flow paths separated from the branch And adjusting means.

  According to the third aspect of the present invention, the temperature of the fuel cell can be precisely adjusted by adjusting, for example, the opening degree of the flow rate adjusting valve, which is the flow rate adjusting means. Thereby, the power generation efficiency of the fuel cell can be maintained high. Even if there is only one refrigerant pump, the temperature control of the electric drive system and the fuel cell can be performed appropriately. That is, even if there is only one refrigerant pump, by adjusting the opening of the flow distribution adjusting valve, the flow rate ratio of the two channels separated from the branch is adjusted, and the two systems that require different cooling capacities The cooling function of the cooling system can be balanced.

  According to a fourth aspect of the present invention, in the third aspect of the present invention, the first temperature sensor that detects the temperature of the refrigerant that has cooled the elements of the electric drive system, and the temperature of the refrigerant that has cooled the fuel cell. The apparatus further includes a second temperature sensor to be detected, and a control unit that controls the upstream flow rate ratio adjusting unit based on outputs of the first temperature sensor and the second temperature sensor.

  According to the invention described in claim 4, the ratio between the flow rate of the refrigerant supplied to the elements of the electric drive system and the flow rate of the refrigerant bypassing the electric drive system is adjusted based on the outputs of the two temperature sensors. The In this configuration, the temperature of the element of the electric drive system rises, and if the further cooling is necessary, the former flow rate is increased. If the temperature of the fuel cell rises and further cooling is required, the latter control is performed to increase the flow rate. Thereby, even if there is one refrigerant pump, management of the cooling function of the two systems is appropriately performed.

  According to a fifth aspect of the present invention, in the first aspect of the present invention, the refrigerant discharged from the fuel cell is supplied to the elements of the electric drive system without passing through the plurality of radiators. The apparatus further comprises supply means.

  According to the fifth aspect of the present invention, when the temperature of the fuel cell is at a low temperature at which the power generation efficiency is lowered, the refrigerant that does not pass the radiator is supplied to the element of the electric drive system, and further, the element of the electric drive system. The refrigerant whose temperature has been increased is supplied to the fuel cell. As a result, the amount of heat is supplied to the fuel cell, and the low temperature state of the fuel cell described above is eliminated.

  ADVANTAGE OF THE INVENTION According to this invention, the cooling system of a fuel cell and the cooling system of an electric drive system are integrated, and the technique which circulates a cooling medium to both cooling systems with the same pump is provided.

It is a block diagram which shows the outline | summary of the cooling system of embodiment. It is a block diagram which shows the outline | summary of the control system of embodiment. It is a flowchart which shows an example of the control operation of embodiment. It is a graph which shows the relationship between the state of a vehicle, and each parameter. It is a block diagram which shows the outline | summary of the cooling system of embodiment. It is a block diagram which shows the outline | summary of the conventional cooling system.

1. First Embodiment (Configuration of Cooling System)
Hereinafter, an embodiment of the present invention will be described with reference to FIG. FIG. 1 shows an outline of a cooling system mounted on a vehicle. In FIG. 1, the upper side of the figure is the front in the traveling direction of the vehicle. FIG. 1 mainly shows the configuration of the cooling system of the cooling system. In FIG. 1, a cooling system 100 is shown. Note that the structure of the vehicle is not particularly limited as long as the vehicle has a mechanism that travels by electric power, and thus the description of the structure of the vehicle is omitted.

  The cooling system 100 includes a first radiator 101 and a second radiator 102. The first radiator 101 is disposed on the front side when viewed from the front in the traveling direction of the vehicle, and the twenty-second radiator 102 is disposed on the rear side. These two radiators have a structure extending in the width direction of the vehicle. The cooling water is first supplied from the refrigerant path 103 to the second radiator, air-cooled there, and then sent to the first radiator 101, where it is further air-cooled.

  The cooling water cooled by the first radiator 101 is sent to the thermo valve 104 (supply means). The thermo valve 104 functions as a bypass valve that can bypass the coolant from the refrigerant flow path 103 to the second radiator 102 and bypass the coolant to the branch point 106 via the bypass path 105. When the thermo valve 104 is not in the above-described bypass state, the bypass path 105 is closed and the cooling water flowing through the refrigerant flow path 103 is supplied to the second radiator 102.

  A branch point 106 that divides the flow path into two is disposed on the downstream side of the thermo valve 104. One flow path branched from the branch point 106 guides cooling water to the electric drive system 107. The other flow path branched from the branch point 106 is a bypass flow path that bypasses the electric drive system 107 and guides the cooling water to the flow rate distribution control valve 108 (flow rate ratio adjusting means).

  The electric drive system 107 includes a vehicle drive motor that is an element (an object to be cooled) cooled by cooling water, and a semiconductor device of a drive circuit that drives the motor. The flow rate distribution control valve 108 has a structure that can be opened and closed, and has a function of adjusting the flow rate passing therethrough.

  A temperature sensor 1 (109) is disposed downstream of the electric drive system 107. The temperature of the cooling water that cools the electric drive system 107 and takes heat away from the electric drive system 107 is detected by the temperature sensor 1 (109). The cooling water whose temperature is detected by the temperature sensor 1 (109) merges with the cooling water from the flow rate distribution control valve 108 and is sent to the pump 110. The pump 110 is a device for giving a flow to the cooling water. The pump 110 is driven by a motor (not shown) and sends the cooling water discharged from the electric drive system 107 and the flow distribution control valve 108 toward the fuel cell 111 for cooling. Cooling water is circulated within the system 100.

  The fuel cell 111 has a structure in which a plurality of cells are stacked, and includes a refrigerant flow path through which cooling water flows. The cooling water that has cooled the fuel cell 111 is discharged to the refrigerant flow path 103. In the vicinity of the fuel cell 111 in the refrigerant flow path 103, the temperature sensor 2 (112) is arranged. The temperature sensor 2 (112) detects the temperature of the cooling water discharged from the fuel cell 111.

(Outline of cooling water flow)
First, the outline of the flow of the cooling water in the case where the refrigerant flow path 103 → the second radiator 102 → the first radiator 101 → the thermo valve 104 and the flow path are set without setting the thermo valve 104 to the bypass state is briefly described. explain. In this case, the cooling water flowing through the refrigerant flow path 103 is cooled in the second radiator 102, then sent to the first radiator 101, further cooled there, and discharged toward the thermo valve 104.

  The cooling water that has passed through the thermo valve 104 is branched into two paths at a branch point 106, and one of them is sent to the pump 110 after cooling the electric drive system 107. The other branched part passes through the flow rate distribution control valve 108, joins the cooling water that has cooled the electric drive system 107, and is sent to the pump 110. The cooling water pumped by the pump 110 is sent to the fuel cell 111, and after cooling the fuel cell 111, it is sent to the refrigerant flow path 103.

  When the thermo valve 104 is in the bypass state, the cooling water flowing through the refrigerant flow path 103 is bypassed to the bypass path 105 and does not pass through the second radiator 102 and the first radiator 101, and from the thermo valve 104 to the branch point 106. Supplied. The subsequent flow of the cooling water is the same as when the thermo valve 104 is not bypassed.

  If the opening degree of the flow distribution control valve 108 (the degree of opening of the valve) is adjusted in the flow of the cooling water, the flow rate ratio of the cooling water branched at the branch point 106 changes. For example, when the opening degree of the flow distribution control valve 108 is increased (when the opening / closing of the valve is increased), the flow rate of the cooling water flowing through the flow distribution control valve 108 is increased, and the flow rate of the cooling water flowing through the electric drive system 107 is decreased. To do. Since the cooling water after passing through the electric drive system 107 has a higher temperature than the cooling water after passing through the flow distribution control valve 108, in this case, the temperature of the cooling water supplied to the fuel cell 111 is lowered.

  On the contrary, when the opening degree of the flow distribution control valve 111 is decreased (when the opening / closing of the valve is decreased), the flow rate of the cooling water flowing through the flow distribution control valve 108 decreases, and the flow rate of the cooling water flowing through the electric drive system 107 is reduced. To increase. In this case, the ability to cool the electric drive system 107 increases, but the temperature of the cooling water supplied to the fuel cell 111 increases.

(Control system configuration)
FIG. 2 is a block diagram showing a control system of the system shown in FIG. The control system shown in FIG. 1 includes a controller 201 (control means). The controller 201 has a function as a computer and includes a CPU, a memory, and an interface circuit. The controller 201 executes a control procedure described later, and performs cooling control in the cooling system 100.

  2 includes the thermo valve 104, the pump 110, the flow distribution control valve 108, the temperature sensor 1 (109), and the temperature sensor 2 (112), which are also shown in FIG. The controller 201 controls the thermo valve 104, the pump 110, and the flow rate distribution control valve 108 based on detection signals of the temperature sensor 1 (109) and the temperature sensor 2 (112). A specific example of this control will be described later.

(Example of control)
FIG. 3 is a flowchart showing an example of an execution procedure of control performed in the control system of FIG. The control shown in FIG. 3 is executed by the controller 201 based on the control program stored in the memory in the controller 201 of FIG.

  For example, when the vehicle equipped with the cooling system 100 is turned on (turned on) and the brake is released and the accelerator is depressed, the vehicle can be driven. Be started. When the process is started (step S301), the pump 110 is started (step S302), and the circulation of the cooling water is started. In the initial state, it is assumed that the flow rate distribution control valve 108 is set to an opening obtained experimentally in advance.

  Next, the temperature detected by the temperature sensor 2 (112) is referred to, and the temperature of the cooling water discharged from the fuel cell 111 is within a predetermined low temperature range (in this example, a range of 10 ° C. or less). Is determined (step S303). If the temperature of the cooling water from the fuel cell 111 is in a predetermined low temperature range, the cooling water flowing through the refrigerant channel 103 does not pass through the second radiator 102 and the first radiator 101 and branches from the thermo valve 104. The thermo valve 104 is switched so as to flow to the point 106 (step S304). Thus, the cooling water from the refrigerant flow path 103 is not cooled by the radiator.

  In step S303, if the temperature of the cooling water discharged from the fuel cell 107 is not in the range of 10 ° C. or lower, the process proceeds to step S305, where the refrigerant flow path 103 → second radiator 102 → first radiator 101 → thermo valve 104. The thermo valve 104 is switched so that the flow path is connected. At this time, the bypass path 105 is closed.

  After step S304 or step S305, it is determined whether or not the temperature detected by the temperature sensor 1 (109) exceeds a predetermined upper limit (70 ° C. in this example) (step S306). If the temperature detected by the temperature sensor 1 (109) exceeds 70 ° C., the flow distribution control valve 108 is controlled in the closing direction (small opening) so that the cooling water supplied to the electric drive system 107 increases. Adjustment is performed (step S307). The control in the closing direction is performed with a predetermined change width. At this time, control for increasing the output of the pump 110 may be used in combination. After performing the process of step S307, the processes of step S303 and subsequent steps are repeated.

  In step S306, if the detected temperature of temperature sensor 1 (109) is 70 ° C. or lower, the process proceeds to step S308, and the detected temperature of temperature sensor 2 (112) is set to a predetermined upper limit value (in this case, 95 ° C.). A determination is made as to whether it has exceeded. When the detected temperature of the temperature sensor 2 (112) exceeds 95 ° C., the flow distribution control valve 111 is opened (large opening) so that the flow rate of the cooling water flowing through the flow distribution control valve 108 increases. Adjustment is made (step S309).

  In this case, the flow rate of the cooling water flowing through the electric drive system 107 is decreased, and on the other hand, the flow rate of the cooling water that is cooled by the radiator and passes through the flow distribution control valve 108 is increased. The amount of heat decreases, and the temperature of the cooling water supplied to the fuel cell 111 decreases. For this reason, the cooling efficiency of the fuel cell 111 is increased.

  Note that the control in the opening direction of the flow rate distribution control valve 108 in step S309 is performed with a predetermined change width. At this time, control for increasing the output of the pump 110 may be used in combination.

  After step S309 or in step S308, if the detected temperature of the temperature sensor 2 (112) does not exceed 95 ° C., the process proceeds to step S310, and it is determined whether or not to end the process. For example, when the start key is removed (turned off), the determination in step S310 is YES, and the control ends (step S311). If the control is to be continued, the process returns to the previous stage of step S303, and the processes after step S303 are repeated.

(function)
When the temperature of the fuel cell 111 is low, the reaction for power generation becomes low efficiency, and the output of the fuel cell 111 becomes lower than a specified value. In such a case, it is not appropriate to cool the fuel cell. In the control shown in FIG. 3, when this low temperature state is detected in step S303, the process proceeds to step S304, and the supply of cooling water to the radiator is shut off. As a result, the cooling action by the radiator of the cooling water supplied to the electric drive system 104 is stopped, the temperature of the cooling water discharged from the electric drive system 107 rises, and the cooling water sent from the pump 110 to the fuel cell 111. The temperature rises. As a result, the fuel cell 111 is heated by the exhaust heat of the electric drive system 107, and the reaction efficiency is improved. This action is particularly effective at the start of the vehicle in winter and cold regions.

  In particular, the semiconductor device of the electric drive system 107 is vulnerable to a high temperature, and it is important to set the temperature below the set upper limit. In the control illustrated in FIG. 3, the temperature of the electric drive system 107 is monitored by the temperature sensor 1 (109), and when the temperature exceeds a predetermined temperature, the process proceeds from step S306 to step S307, and the electric drive system The flow rate of the cooling water for cooling 107 is increased and its cooling function is strengthened. For this reason, overheating of the electric drive system 107 is prevented.

  When the temperature of the fuel cell 107 is higher than an appropriate temperature range, the power generation efficiency is reduced due to drying of the electrolyte membrane or the like. For this reason, it is important that the fuel cell 107 does not exceed a certain temperature in order to exhibit a prescribed power generation capacity.

  In the control shown in FIG. 3, the temperature sensor 2 (112) monitors the temperature of the cooling water discharged from the fuel cell 111. If the temperature of the fuel cell 111 exceeds a predetermined temperature, the steps from step S308 to step S308 are performed. Proceeding to S309, the temperature of the cooling water for cooling the fuel cell 107 is lowered. As a result, the cooling efficiency of the fuel cell 111 is increased, and a decrease in power generation efficiency due to overheating of the fuel cell 111 is suppressed.

(Superiority)
As described above, in the present embodiment, in consideration of the flow of cooling water, the flow path is branched downstream of the second radiator 102 and the first radiator 101, and one is supplied to the electric drive system 107. The other is supplied to the flow distribution control valve 108. Then, the cooling water that has taken heat from the electric drive system 107 and the cooling water that has passed through the flow distribution control valve 108 are merged before the pump 110, pumped by the pump 110, and supplied to the fuel cell 111.

  In this configuration, the cooling water cooled by the radiator is supplied as it is to the electric drive system 107, and the cooling water cooled by the radiator and the heat from the electric drive system 107 are cooled to the fuel cell after being cooled by the radiator. The cooling water deprived of the water is mixed and supplied. For this reason, the cooling water circulation required for cooling the electric drive system 107 that needs to be maintained at a relatively low temperature and the fuel cell 111 that needs to be maintained at a relatively high temperature is performed by one pump 110. I can cover it. Further, the temperature of the cooling water supplied from the pump 110 to the fuel cell 111 is adjusted by adjusting the mixing ratio when the branched one is mixed again by the flow rate distribution control valve 108. Since this adjustment can be performed precisely, control for maintaining the temperature of the fuel cell at a temperature suitable for power generation can be easily performed.

  In the present embodiment, by using the flow distribution control valve 108, only one pump 110 may be necessary to realize the above-described function. That is, by distributing the cooling water circulated by one pump and changing the distribution ratio, the flow rate of the cooling water supplied to the electric drive system 107 and the temperature of the cooling water supplied to the fuel cell 111 are changed. Control and adjust each to have proper cooling function. For this reason, the structure of the pump system is simplified, and advantages such as downsizing, cost reduction, and weight reduction of the cooling system can be obtained.

  Further, by arranging the first radiator 101 and the second radiator 102 in order from the front of the traveling direction of the vehicle, an effective air cooling structure using a limited space inside the vehicle can be obtained.

(Concrete example)
FIG. 4 is a graph conceptually showing the relationship between the vehicle state and each parameter. The unit of the graph axis is a relative value. In FIG. 4A, the horizontal axis represents the time axis, and the vertical axis represents the vehicle speed (dashed line) and the state of vehicle inclination (solid line). FIG. 4 (A) shows a state in which the vehicle first goes up the hill, then flattenes when the hill is fully climbed, immediately goes downhill, and travels horizontally when the downhill has been completed. And the change of the vehicle speed in this case is shown.

  FIG. 4B shares a time axis (horizontal axis) with FIG. 4A, and the vertical axis indicates temperature. Here, the temperature of the semiconductor device of the drive circuit that drives the motor in the electric drive system 107 is indicated by a solid line, and the temperature inside the fuel cell 111 is indicated by a broken line.

  FIG. 4C shares the time axis (horizontal axis) with FIG. 4A, and the vertical axis indicates the opening of the flow distribution control valve 111.

  In this example, as shown in FIG. 4C, when the hill is first climbed, the opening of the fuel distribution control valve 108 is set to a small opening, and the fuel cell 111 is cooled. Compared with the cooling of the semiconductor device of the electric drive system, the temperature of the fuel cell 111 rises with an increase in power generation when climbing up. On the other hand, the temperature of the semiconductor device of the electric drive system 107 is sufficiently cooled and rises very slowly.

  Since the load applied to the electric motor is suddenly reduced at the stage where the hill goes up in FIG. 4 (A), the temperature of the semiconductor device does not increase as shown in FIG. 4 (B). On the other hand, in the fuel cell 111, since the extraction of current is reduced, the generation of heat continues, although the generation of reaction heat is somewhat reduced, and the internal temperature rises and the temperature gradually increases.

  In this example, when the temperature inside the fuel cell 111 rises to a certain level (time t1), the opening degree of the fuel distribution control valve 108 is increased and the flow rate of the cooling water supplied to the fuel cell 111 is increased. Is done. For this reason, as shown in FIG. 4B, the heat inside the fuel cell 111 is surely taken away by the increased cooling water, and the internal temperature changes from rising to falling.

  Further, FIG. 4B shows a state in which the temperature of the semiconductor device of the electric drive system 107 gradually increases due to the effect of increasing the supply ratio of the cooling water to the fuel cell 111. Then, as shown in FIG. 4A, as the vehicle goes downhill and the vehicle speed increases, the load on the electric drive system 107 increases, and the temperature of the semiconductor device approaches the predetermined management water temperature upper limit.

  At this time, the opening degree of the flow distribution control valve 108 is reduced at time t2 in FIG. Thereby, the supply amount of the cooling water to the electric drive system 107 increases, the temperature rise of the semiconductor device is suppressed, and the temperature decreases. On the other hand, in the fuel cell 111, the temperature changes from a moderate temperature rise to a slightly sudden temperature rise.

  Here, as shown in FIG. 4 (A), the vehicle reaches a time t3 in FIG. 4 (C) in a state where the vehicle is running horizontally and the vehicle speed is constant. At the time t3, the temperature of the semiconductor device of the electric drive system 107 has decreased by a considerable amount from the predetermined management water temperature upper limit, and the opening of the fuel distribution control valve 108 is fixed at a position where it is not over-throttle. By doing so, the temperature of the semiconductor device of the electric drive system 104 is stabilized at a constant value.

  FIG. 4B shows a state in which the temperature rise of the fuel cell 111 is suppressed and becomes a constant value at time t3. This is because the amount of charge from the fuel cell 111 to a battery (not shown in FIG. 1) increases while the vehicle speed becomes constant, and the ratio of power supply from the battery to the electric drive system 107 increases. This is because the load amount of the battery 111 is reduced and generation of reaction heat is suppressed.

2. Second Embodiment FIG. 5 is a block diagram illustrating another aspect of the embodiment. In FIG. 5, a cooling system 600 is shown. The cooling system 600 differs from the cooling system 100 of FIG. 1 in the position of the flow distribution control valve. In this example, the flow rate distribution control valve 113 is arranged on the downstream side of the electric drive system 107 and on the upstream side where the branch path from the branch point 106 joins.

  In this configuration, when the opening degree of the flow distribution control valve 113 is increased, the flow rate of the cooling water to the electric drive system 107 is increased, and the cooling effect of the electric drive system 107 is increased. Further, when the opening degree of the flow distribution control valve 113 is reduced, the flow rate of the cooling water to the electric drive system 107 is reduced, the temperature of the cooling water sent to the fuel cell 111 is lowered, and the cooling effect of the fuel cell 111 is high. Become.

3. Others A flow rate adjustment control valve may be arranged in both of the two systems of flow paths branched from the branch point 106. In this case, the process of step S307 and step 309 of FIG. 3 is performed by adjusting the opening degree of at least one of the two flow rate adjustment control valves.

  In the configuration shown in FIG. 1, a configuration without the flow distribution control valve 108 is also conceivable. In this case, the distribution ratio of the cooling water to the electric drive system 107 and the flow rate distribution control valve 108 is fixed. In this case, the distribution ratio is set by adjusting the conductance of the flow of the cooling water flowing through each flow path. This adjustment can be performed by setting the inner diameter of the pipe or adjusting a valve (not shown) disposed in the middle of the refrigerant flow path.

  The temperature threshold value detected and managed by the temperature sensors 1 and 2 can be changed according to the scale and type of the fuel cell, the scale of the electric drive system, the circuit configuration, and the like. The vehicle is not particularly limited as long as it travels by electric vehicle for the purpose of transporting passenger cars, trucks, buses, and other people and luggage. The refrigerant is not limited to water as long as it is a fluid for cooling. Further, the number of radiators is not limited to two and may be three or more. The position of the pump may be between the refrigerant flow path 103 or the thermo valve 104 and the branch point 106.

  The present invention can be applied to an in-vehicle cooling system.

  DESCRIPTION OF SYMBOLS 100 ... Cooling system, 101 ... 1st radiator, 102 ... 2nd radiator, 103 ... Refrigerant flow path, 104 ... Thermo valve, 105 ... Bypass path, 106 ... Branch point, 107 ... Electric drive system, 108 ... Flow distribution Control valve 109 ... temperature sensor 1, 110 ... pump, 111 ... fuel cell, 112 ... temperature sensor 2, 201 ... controller, 600 ... cooling system.

Claims (5)

In a vehicle equipped with a fuel cell that can be driven by electricity,
A plurality of radiators extending in the width direction of the vehicle,
An element of an electric drive system to be cooled, which is disposed downstream of the flow of refrigerant from the plurality of radiators;
A fuel cell cooled by a refrigerant after cooling elements of the electric drive system;
A cooling system for a vehicle equipped with a fuel cell, comprising: a refrigerant pump for supplying a flow to the refrigerant.   2. The fuel cell vehicle cooling system according to claim 1, wherein the plurality of radiators are arranged in multiple stages along an air flow direction when the vehicle moves forward. 3. A branch arranged upstream of the element of the electric drive system and for dividing the flow of the refrigerant;
A refrigerant bypass flow path for bypassing the element of the electric drive system with the refrigerant separated from the branch and joining the refrigerant that has cooled the element of the electric drive system on the downstream side;
The fuel cell-equipped vehicle cooling system according to claim 1, further comprising: a flow rate ratio adjusting unit that adjusts a flow rate ratio of the two flow paths separated from the branch. A first temperature sensor for detecting the temperature of the refrigerant that has cooled the elements of the electric drive system;
A second temperature sensor for detecting the temperature of the refrigerant that has cooled the fuel cell;
The fuel cell-equipped vehicle according to claim 3, further comprising: a control unit that controls the upstream flow rate ratio adjusting unit based on outputs of the first temperature sensor and the second temperature sensor. Cooling system. The fuel cell according to any one of claims 1 to 4, further comprising supply means for supplying the refrigerant discharged from the fuel cell to the elements of the electric drive system without passing through the plurality of radiators. Onboard vehicle cooling system.

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