JP4977956B2 - Cooling control device for fuel cell system - Google Patents

Description

  The present invention relates to a cooling control device for a fuel cell system including a radiator and a fan for cooling the fuel cell.

  In a fuel cell, a fuel gas such as hydrogen gas and an oxidizing gas containing oxygen are electrochemically reacted through an electrolyte, and electric energy is directly taken out between electrodes provided on both surfaces of the electrolyte. In particular, a polymer electrolyte fuel cell using a polymer electrolyte has attracted attention as a power source for electric vehicles because of its low operating temperature and easy handling. That is, a fuel cell vehicle is equipped with a hydrogen storage device such as a high-pressure hydrogen tank, a liquid hydrogen tank, or a hydrogen storage alloy tank in the vehicle, and reacts by supplying hydrogen supplied therefrom and air containing oxygen to the fuel cell. This is the ultimate clean vehicle that drives the motor connected to the drive wheels with the electric energy extracted from the fuel cell, and the only exhaust material is water.

  Usually, in order to keep the operating temperature of the fuel cell optimal, a cooling system for circulating a coolant between the fuel cell and the radiator is provided. The radiator is provided with a radiator fan for sending air to the radiator.

  Such a radiator has a reduced heat dissipation capability as the outside air temperature increases. As a technique for maintaining the fuel cell in an appropriate temperature range even when the outside air temperature rises, there is a technique for obtaining an output upper limit value from the outside air temperature by an output upper limit function and limiting the output of the fuel cell to this output upper limit value ( For example, Patent Document 1).

In addition, as a noise reduction technology for fuel cell vehicles, the frequency of noise (fundamental frequency and second harmonic) generated when a rotary device such as a pump or fan is idle is set to be 30 Hz or more away from each other. There is a technique to reduce (for example, Patent Document 2).
JP-A-5-074477 (page 3, FIG. 1) JP 2004-178847 A (4th page, FIG. 1)

  However, when the output restriction described in Patent Document 1 is applied, there is a problem that the temperature of the coolant rises and the output restriction is applied, and the power performance is also deteriorated.

  In the technique described in Patent Document 2, noise can be reduced by limiting the number of revolutions of the fan of the radiator, but as a rebound, the temperature of the coolant rises except during idling, and the electrolyte membrane of the fuel cell The problem was that it dried and had a negative effect on power generation.

In order to solve the above-described problems, the present invention provides a fuel cell that generates power by an electrode reaction between an anode and a cathode that sandwich an electrolyte membrane, a cooling system that circulates a coolant between the fuel cell and a radiator, In a cooling control device of a fuel cell system including a fan that blows air to a radiator, fan rotation speed limiting means that limits the rotation speed of the fan, coolant temperature detection means that detects the temperature of the coolant, and the detection A restriction release means for releasing the fan speed limit by the fan speed limit means when the coolant temperature exceeds a predetermined temperature threshold, the load of the fuel cell, the pure water tank water level, Depending on the operating state of the fuel cell, which is one of the cathode outlet air temperature, the output limit state of the fuel cell, or the deviation between the target output of the fuel cell and the output limit value , And summarized in that to change the temperature threshold to release the rotational speed limit of the fan.

  According to the present invention, when the coolant temperature rises above the predetermined temperature threshold, the rotational speed limit of the fan is released. Therefore, when the coolant temperature is high, the fuel is more effective than the noise vibration suppression. By giving priority to cooling of the battery, there is an effect that the electrolyte membrane can be wetted (hereinafter, referred to as water management) while keeping the humidity of the cathode and anode appropriate.

  Further, the output restriction is relaxed in accordance with the temperature rise of the coolant, and there is an effect that the output performance of the fuel cell can be prevented from being lowered.

  Next, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a configuration diagram showing a first embodiment of a cooling control device for a fuel cell system according to the present invention. The fuel cell 1 is a fuel cell using a solid polymer electrolyte. The fuel cell 1 is supplied with hydrogen gas at the anode and air at the cathode by a hydrogen supply means and an air supply means (not shown), and the electrode reaction shown below proceeds to generate electric power.

Anode (hydrogen electrode): H ₂ → 2H ⁺ + 2e ⁻ (1)
Cathode (oxygen electrode): 2H ⁺ + 2e ⁻ + (1/2) O ₂ → H ₂ O (2)
The fuel cell 1 and the radiator 3 are connected so that the coolant line 5 forms a circulation path. The pump 2 circulates the coolant between the fuel cell 1 and the radiator 3. The fan 4 sends air to the radiator 3 to cool the coolant.

  The cooling control device 6 includes a temperature sensor 7, a vehicle speed detection means 8, a sound vibration request fan limit rotation speed calculation means 9, a temperature control fan rotation speed calculation means 10, a fan rotation speed limit means 11, and a restriction release. And means 12.

  The temperature sensor 7 measures the coolant temperature at the fuel cell inlet. The temperature control fan rotation speed calculation means 10 calculates the required fan rotation speed for controlling the coolant temperature at the fuel cell inlet detected by the temperature sensor 7 to the target temperature.

  The vehicle speed detection means 8 detects the vehicle speed. The sound vibration request fan limit rotation speed calculation means 9 calculates the upper limit rotation speed of the fan 4 according to the vehicle speed and the coolant temperature. This fan upper limit rotation speed is calculated, for example, so that the fan rotation speed limit corresponding to the vehicle speed is relaxed as the coolant temperature increases.

  The limiter 11 calculates the temperature control fan speed by selecting the smaller one of the fan speeds calculated by the sound vibration request fan limit speed calculator 9 and the temperature control fan speed calculator 10. The temperature control fan rotation speed calculated by the means 10 is limited to the sound vibration request fan rotation speed calculated by the sound vibration request fan limit rotation speed calculation means 9.

  The restriction release unit 12 releases the fan rotation speed restriction applied by the fan rotation number restriction unit 11 in accordance with the coolant temperature detected by the temperature sensor 7. When canceling, the fan speed calculated by the temperature control fan speed calculator 10 is selected.

  FIG. 2 is a calculation block diagram of the sound vibration demand fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11 and the limit release means 12 in this embodiment.

  The sound vibration request fan limit rotation speed calculation means 9 calculates the fan upper limit rotation speed according to the vehicle speed, using a table indicating the relationship of the fan upper limit rotation speed to the vehicle speed. Since the noise of the fan 4 becomes easier to hear as the vehicle speed decreases, the table value is set so that the fan upper limit rotational speed decreases as the vehicle speed decreases.

  The temperature control fan speed calculator 10 calculates a target fan speed for maintaining the coolant temperature at the target temperature by, for example, PI control calculation based on a deviation between the target temperature of the coolant and the measured temperature. When the measured temperature deviates from the target temperature, the feedback of PI control works and the fan rotation speed is corrected, and the measured temperature can be returned to the target temperature.

  The fan rotation speed limiting means 11 selects the smaller one of the fan upper limit rotation speed output from the sound vibration request fan limit rotation speed calculation means 9 and the target fan rotation speed output from the temperature control fan rotation speed calculation means 10. The fan speed is limited to the sound vibration request fan limit speed.

  The restriction releasing means 12 is a comparator 22 that compares the threshold value with the measured coolant temperature, and the rotation speed of the fan rotation speed limiting means 11 or the rotation of the temperature control fan rotation speed calculation means 10 according to the comparison result. A rotation speed instruction value switch 23 for switching between numbers is provided.

  The restriction release means 12 determines whether or not the coolant temperature detected by the temperature sensor 7 has exceeded a predetermined threshold, and does not exceed it by switching the rotation speed instruction value switch 23 based on the determination result. In this case, the output of the fan rotation speed limiting means 11 is selected, and if it exceeds, the output of the temperature control fan rotation speed calculation means 10 is selected to cancel the restriction on the sound vibration request fan upper limit rotation speed.

  Here, a temperature threshold value that does not deteriorate water management or power performance is set as the threshold value. Also, by releasing after the measured temperature of the coolant exceeds the threshold for a predetermined time, even if noise is intervening in the measured temperature of the coolant, it is possible to prevent erroneous release of the fan speed limit. be able to.

  FIG. 3 is a time chart showing changes over time in vehicle speed, fan rotation speed, and fuel cell inlet coolant temperature. (A) Vehicle speed, (b) Fan rotation speed, (c) Coolant temperature indicates the case where the fan rotation speed limitation is not released, (d) Vehicle speed, (e) Fan rotation speed, (f) Coolant temperature is The case where the fan rotation speed limitation is released is shown.

For example, as shown in FIG. 3 (a), when the vehicle speed is suddenly decelerated from a high state,
・ Fuel cell heat capacity ・ Running wind reduction ・ Sound vibration request fan upper limit rotation speed reduction (Fig. 3 (b))
As a result, the temperature of the cooling liquid temporarily rises as shown in FIG. At this time, if the temperature of the coolant does not exceed the fan restriction release temperature threshold, the actual rotation speed of the fan is limited to the sound vibration request fan upper limit rotation speed as shown in FIG.

For example, as shown in FIG. 3 (d), when the vehicle speed is high and the vehicle goes downhill, the vehicle speed decreases.
・ Increase in heat generation due to increase in fuel cell output ・ Reduction in running wind ・ Reduction of upper limit number of rotations required for sound vibration request fan
As a result, the temperature of the coolant rises as shown in FIG. If the temperature of the coolant exceeds the fan limit release temperature threshold, the sound vibration request fan rotation speed limit is released, and the actual fan rotation speed matches the target temperature control fan rotation speed.

  The timing at which the rotational speed restriction is restored after the fan rotational speed restriction is released is when the coolant temperature falls below a fan restriction return temperature threshold that is lower than the release temperature threshold for a predetermined time. Thus, by providing a hysteresis between the rotation speed limit release and the rotation speed limit return, it is possible to prevent hunting between the release and the return.

  According to the first embodiment described above, when the coolant temperature rises above the predetermined temperature threshold, the fan speed limit is released, so that noise vibration occurs when the coolant temperature is high. By giving priority to the cooling of the fuel cell over the suppression of the above, there is an effect that the humidity of the cathode and the anode can be appropriately maintained and the electrolyte membrane can be moistened.

  Further, the output restriction is relaxed in accordance with the temperature rise of the coolant, and there is an effect that the output performance of the fuel cell can be prevented from being lowered.

  Further, according to this embodiment, when the coolant temperature exceeds the temperature threshold for a predetermined time, the fan speed limit is canceled, so that when noise is intervening in the measured coolant temperature, There is also an effect that it is possible to prevent erroneous release.

  Furthermore, according to the present embodiment, when the fan rotation speed limit is canceled and the coolant temperature falls below a predetermined temperature threshold value lower than the release temperature threshold value for a predetermined time, the fan rotation speed limit is restored. In addition, hysteresis can be provided between the rotational speed limit, release and return, and there is an effect that hunting of release and return can be prevented.

  Next, a second embodiment of the cooling control device for the fuel cell system according to the present invention will be described. FIG. 4 is a configuration diagram illustrating the second embodiment. The air conditioner ON / OFF detecting means 13 for detecting the on / off state of the air conditioner is added to the configuration of the first embodiment shown in FIG. 1, thereby detecting whether the operating state of the air conditioner is on or off. The restriction releasing unit 12 releases the fan rotation speed limitation applied by the fan rotation number limiting unit 11 according to the operating state of the air conditioner and the coolant temperature. Since the other configuration is the same as that of the first embodiment, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 5 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11 and the limit release means 12 in this embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 5, the restriction release unit 12 of the present embodiment includes a threshold value A in an air conditioner ON state, a threshold value B in an air conditioner OFF state (threshold value A> threshold value B), and a threshold value switch 21 that switches and outputs these two threshold values. And the comparator 22 that compares the output of the threshold switch 21 and the measured coolant temperature by the temperature sensor 7, and the rotational speed of the fan rotational speed limiting means 11 or the temperature control according to the comparison result of the comparator 22. A rotation speed instruction value switch 23 for switching between the rotation speed of the fan rotation speed calculation means 10 is provided.

  The restriction release means 12 determines whether or not the measured temperature of the coolant has exceeded a predetermined threshold value, and if not, selects the output of the fan rotation speed restriction means 11. By selecting the output of the number calculation means 10, the restriction on the sound vibration request fan upper limit rotational speed is released.

  Here, the threshold value is provided in two stages, and the threshold value A when the air conditioner operating state is on is set higher than the threshold value B when the air conditioner is off. The reason why such a setting is possible will be described using the relationship among the output current of the fuel cell, the coolant temperature, and the water balance shown in FIG. As the output current of the fuel cell increases, the amount of water produced per unit time increases, so the water balance becomes positive. In addition, the lower the coolant temperature, the lower the water vapor pressure contained in the cathode exhaust, and the more difficult it is to dry the cathode, resulting in a positive water balance. When the air conditioner operating state is ON, the output current corresponding to the power consumption of the air conditioner increases. Therefore, even if the coolant temperature is high to some extent, the water balance is positive. Therefore, the coolant having a positive water balance as shown in FIG. It becomes possible to set the temperature as the fan limit release temperature threshold.

  According to the second embodiment described above, the temperature threshold value for releasing the fan speed limit restriction is provided in two stages, and the temperature threshold value in the air conditioner on state is set higher than the temperature threshold value in the air conditioner off state. The fuel cell output is increased by the amount of power consumed, and the amount of water produced can be increased accordingly, which is advantageous for water management. Therefore, an effect of reducing fan noise can be obtained by setting the temperature threshold value for releasing the fan rotation speed limit high.

  In general, a condenser for an air conditioner is attached in the vicinity of the radiator. When the air conditioner is turned on, the condenser generates heat, and the wind hitting the radiator is warmed, which is disadvantageous for cooling the coolant. Therefore, in the air conditioner ON state, the fan rotation speed limit can be easily prevented from being released by setting the temperature threshold value for releasing the fan rotation speed restriction high.

  Next, a third embodiment of the cooling control device of the fuel cell system according to the present invention will be described. FIG. 7 is a configuration diagram illustrating the third embodiment. A power manager 14 for controlling the current taken out from the fuel cell 1 according to the fuel cell target take-out current and a take-out current sensor 15 for detecting the take-out current of the fuel cell 1 are added to the configuration of the first embodiment shown in FIG.

  The restriction releasing unit 12 releases the fan rotation speed limit applied by the fan rotation number limiting unit 11 according to the extraction current detected by the extraction current sensor 15 and the coolant temperature. Since the other configuration is the same as that of the first embodiment, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 8 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11 and the limit release means 12 in the present embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 8, the restriction release means 12 of the present embodiment includes an extraction current-temperature threshold conversion table 24 that stores a fan rotation speed restriction release temperature threshold for the fuel cell extraction current detected by the extraction current sensor 15, a temperature threshold, and a temperature. A comparator 22 that compares the measured coolant temperature by the sensor 7, and the rotation speed of the fan rotation speed limiting means 11 or the rotation speed of the temperature control fan rotation speed calculation means 10 according to the comparison result of the comparator 22. And a rotation speed instruction value switch 23 for switching between the two.

  The restriction release temperature threshold of the extraction current-temperature threshold conversion table 24 is set according to the extraction current of the fuel cell. As described in FIG. 6, the maximum coolant temperature at which the water balance becomes positive increases as the extraction current increases. Therefore, the higher the extraction current, the higher the temperature limit for releasing the fan restriction. It should be noted that the same effect can be obtained by using the extraction power instead of the extraction current from the fuel cell.

  According to the third embodiment described above, since the temperature threshold value for releasing the fan rotation speed limit is increased as the extraction current and extraction power of the fuel cell are increased, the amount of generated water can be increased by the increase in the extraction current and extraction power of the fuel cell. So it is advantageous for water management. Therefore, by setting the temperature threshold value for releasing the fan rotation speed limit high, there is an effect that the noise of the fan can be reduced.

  Next, a fourth embodiment of the cooling control device for the fuel cell system according to the present invention will be described. FIG. 9 is a configuration diagram illustrating the fourth embodiment. A power manager 14 for controlling a current taken out from the fuel cell 1 according to the fuel cell target extraction current is added to the configuration of the first embodiment in FIG.

  The restriction canceling means 12 cancels the fan rotational speed restriction applied by the fan rotational speed limiting means 11 in accordance with the target extraction current of the fuel cell and the coolant temperature. Since the other configuration is the same as that of the first embodiment, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 10 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11 and the limit release means 12 in this embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 10, the restriction release means 12 of the present embodiment includes a target extraction current-temperature threshold conversion table 25 that stores a fan rotation speed limitation release temperature threshold for the fuel cell target extraction current, and a coolant by the temperature threshold and the temperature sensor 7. A comparator 22 that compares the measured temperature, and a rotational speed instruction that switches between the rotational speed of the fan rotational speed limiting means 11 and the rotational speed of the temperature control fan rotational speed computing means 10 according to the comparison result of the comparator 22 And a value switch 23.

  The restriction release temperature threshold of the target extraction current-temperature threshold conversion table 25 is set according to the target extraction current of the fuel cell. The present embodiment is an alternative example in which the extraction current in the third embodiment is replaced with a target extraction current. The same effect can be obtained by using the target extraction power instead of the target extraction current.

  According to the fourth embodiment described above, since the temperature threshold value for releasing the fan speed limitation is increased as the target extraction current and target extraction power of the fuel cell are larger, the target extraction current and the actual extraction power are replaced with the target extraction current and the actual extraction power. By setting the temperature threshold according to the target extraction power, there is an effect that the noise of the fan can be reduced.

  Next, a fifth embodiment of the cooling control device for the fuel cell system according to the present invention will be described. FIG. 11 is a configuration diagram illustrating the fifth embodiment. 1 includes a pure water pump 40 for supplying humidified pure water to the fuel cell 1, a pure water tank 41 for storing pure water, and a water level sensor for detecting the water level of the pure water tank 41. 43 and a pure water conduit 42 for circulating pure water between the fuel cell 1 and the pure water tank 41 are added, and a detection signal of the water level sensor 43 is connected to the restriction releasing means 12. Then, the restriction release means 12 releases the restriction on the fan rotation speed applied by the fan rotation speed restriction means 11 in accordance with the water level signal of the pure water tank and the coolant temperature. Since the other configuration is the same as that of the first embodiment shown in FIG. 1, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 12 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11 and the limit release means 12 in this embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 12, the restriction release means 12 of this embodiment includes a pure water level-temperature threshold conversion table 26 that stores a fan rotation speed restriction release temperature threshold for the pure water tank water level, and a coolant measurement by the temperature threshold and the temperature sensor 7. A comparator 22 that compares the temperature and a rotation speed instruction value that switches between the rotation speed of the fan rotation speed limiter 11 and the rotation speed of the temperature control fan rotation speed calculator 10 according to the comparison result of the comparator 22 And a switch 23.

  The restriction release temperature threshold value of the pure water level-temperature threshold value conversion table 26 is set according to the water level of the pure water tank 41. The higher the pure water tank level, the more water management is available, so the temperature threshold for releasing the fan restriction is set higher.

  According to the fifth embodiment described above, the fan rotation speed limit is canceled according to the coolant temperature and the pure water tank water level. Therefore, the higher the pure water tank water level, the higher the temperature threshold for releasing the fan rotation speed limit. By setting it high, there is an effect that priority can be given to noise reduction of the fan when there is a margin in the amount of pure water for humidification. Further, when the pure water tank water level is low, the generation of humidifying pure water can be promoted by giving priority to cooling by the fan.

  Next, a sixth embodiment of the cooling control device of the fuel cell system according to the present invention will be described. FIG. 13 is a configuration diagram illustrating the sixth embodiment. A compressor 50 for supplying air to the cathode of the fuel cell 1 and a cathode outlet temperature sensor 51 for detecting the air temperature at the cathode outlet are added to the configuration of the first embodiment shown in FIG. , Connected to the restriction release means 12. Then, the restriction releasing means 12 releases the restriction on the fan speed applied by the fan speed limiting means 11 according to the cathode outlet temperature and the coolant temperature. Since the other configuration is the same as that of the first embodiment shown in FIG. 1, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 14 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11, and the limit release means 12 in this embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 14, the restriction release means 12 of this embodiment includes an air temperature-temperature threshold conversion table 27 that stores a fan rotation speed restriction release temperature threshold with respect to the cathode outlet air temperature, and a coolant measured temperature by the temperature threshold and the temperature sensor 7. And a rotational speed instruction value switching for switching between the rotational speed of the fan rotational speed limiting means 11 and the rotational speed of the temperature control fan rotational speed computing means 10 according to the comparison result of the comparator 22 And a container 23.

  The restriction release temperature threshold value of the air temperature-temperature threshold value conversion table 27 is set according to the cathode outlet air temperature. The higher the cathode outlet air temperature, the higher the water vapor pressure contained in the cathode exhaust and the worse the water management. Therefore, the temperature threshold for releasing the fan rotation speed restriction is set low and cooling is given priority.

  According to the sixth embodiment described above, the higher the cathode outlet air temperature, the lower the temperature threshold value for releasing the fan rotation speed limit. Therefore, the higher the cathode outlet air temperature, the easier the electrolyte membrane dries and the power generation becomes more difficult. By lowering the temperature threshold value for releasing the fan rotation speed limit, cooling by the fan can be promoted, and deterioration of water management can be prevented.

  Next, a seventh embodiment of the cooling control device for the fuel cell system according to the present invention will be described. FIG. 15 is a configuration diagram illustrating the seventh embodiment. The power manager 14 for extracting current from the fuel cell 1 and the output limiting means 16 for limiting the extraction current of the fuel cell to prevent the fuel cell from being overheated are added to the configuration of the first embodiment in FIG. The output restriction value of the output restriction means 16 is input to the restriction release means 12. Further, the restriction release unit 12 releases the restriction on the fan rotation speed applied by the fan rotation number restriction unit 11 according to the output restriction value and the coolant temperature. Since the other configuration is the same as that of the first embodiment shown in FIG. 1, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 16 shows a calculation block diagram of the output limiting means 16 in this embodiment. The output restriction means 16 includes an output restriction table 61 that calculates an output restriction value from the coolant temperature, and a select row 62. The output limit table 61 is set so that the output limit value decreases as the coolant temperature at the fuel cell inlet increases. The target extraction current is limited by selecting, with the select row 62, the smaller value of the output limitation value calculated by the output limitation table 61 and the fuel cell target extraction current. The calculated output limit value is used for the limit releasing means 12.

  FIG. 17 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11, and the limit release means 12 in this embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 17, the restriction release unit 12 of this embodiment includes an output limit value-temperature threshold conversion table 28 that stores a fan rotation speed limit release temperature threshold with respect to the output limit value, and a coolant measured temperature by the temperature threshold and the temperature sensor 7. And a rotational speed instruction value switching for switching between the rotational speed of the fan rotational speed limiting means 11 and the rotational speed of the temperature control fan rotational speed computing means 10 according to the comparison result of the comparator 22 And a container 23.

  The restriction release temperature threshold in the output limit value-temperature threshold conversion table 28 is set according to the output limit value. As the output limit becomes tighter and the output limit value decreases, the temperature threshold for releasing the fan limit is set lower, and cooling by the fan has priority.

  According to the seventh embodiment described above, since the temperature threshold value for releasing the fan rotation speed restriction is lowered as the output restriction becomes tighter, it is possible to promote cooling by the fan, relax the output restriction, and improve the power performance. effective.

  Next, an eighth embodiment of the cooling control device for a fuel cell system according to the present invention will be described. FIG. 18 is a configuration diagram illustrating the eighth embodiment. The power manager 14 for extracting current from the fuel cell 1 and the output limiting means 16 for limiting the extraction current of the fuel cell to prevent the fuel cell from being overheated are added to the configuration of the first embodiment in FIG. The output limit value of the output limiting unit 16 and the fuel cell target extraction current are input to the limit canceling unit 12. Further, the restriction releasing means 12 releases the restriction on the fan speed applied by the fan speed limiting means 11 according to the output limit value, the fuel cell target extraction current, and the coolant temperature. Since the other configuration is the same as that of the first embodiment shown in FIG. 1, the same components are assigned the same reference numerals and redundant description is omitted.

  FIG. 19 is a calculation block diagram of the sound vibration request fan limit rotation speed calculation means 9, the temperature control fan rotation speed calculation means 10, the fan rotation speed limit means 11, and the limit release means 12 in this embodiment. The sound vibration request fan limit speed calculating means 9, the temperature control fan speed calculating means 10, and the fan speed limit means 11 are the same as those in the first embodiment shown in FIG.

  In FIG. 19, the limit release means 12 of this embodiment includes a subtractor 29 that calculates a deviation between the target extraction current and the output limit value, and a deviation-temperature threshold conversion that stores a fan rotation speed limit release temperature threshold for this deviation. The table 30, the comparator 22 that compares the temperature threshold value and the coolant measurement temperature by the temperature sensor 7, and the rotation speed of the fan rotation speed limiting means 11 or the temperature control fan rotation according to the comparison result of the comparator 22 A rotation speed instruction value switch 23 for switching the rotation speed of the number calculation means 10 is provided.

  The restriction release temperature threshold value of the deviation-temperature threshold value conversion table 30 is set according to the deviation between the target extraction current and the output restriction value. As this deviation is larger, the actual output cannot be output with respect to the required output for the fuel cell. Therefore, the temperature threshold value for releasing the fan rotation speed restriction is set low, and cooling by the fan is given priority.

  According to the eighth embodiment described above, as the deviation between the target output of the fuel cell and the output limit value increases, the temperature threshold value for releasing the fan speed limit is lowered, so that the difference between the requested output and the actual output is large. In this case, there is an effect that it is possible to relax the output restriction by lowering the temperature threshold value for releasing the fan rotation speed restriction.

1 is a configuration diagram illustrating a first embodiment of a cooling control device for a fuel cell vehicle according to the present invention. FIG. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 1. FIG. 3 is a time chart in the first embodiment. It is a block diagram which shows Example 2 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 2. FIG. It is a figure which shows the relationship between the output electric current in Example 2, a coolant temperature, and a water balance. It is a block diagram which shows Example 3 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 3. FIG. It is a block diagram which shows Example 4 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 4. FIG. It is a block diagram which shows Example 5 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 5. FIG. It is a block diagram which shows Example 6 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 6. FIG. It is a block diagram which shows Example 7 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. FIG. 10 is a block diagram for explaining fuel cell output restriction in a seventh embodiment. It is a block diagram explaining the detail of the fan speed limitation cancellation | release in Example 7. FIG. It is a block diagram which shows Example 8 of the cooling control apparatus of the fuel cell vehicle which concerns on this invention. It is a block diagram explaining the detail of fan rotation speed restrictions cancellation | release in Example 8. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Fuel cell 2 ... Pump 3 ... Radiator 4 ... Fan 5 ... Coolant liquid line 6 ... Cooling control device 7 ... Temperature sensor 8 ... Vehicle speed detection means 9 ... Sound vibration request | requirement fan limitation rotation speed calculation means 10 ... Temperature control fan Rotational speed calculation means 11 ... fan rotational speed restriction means 12 ... restriction release means 13 ... air conditioner on / off detection means 14 ... power manager 15 ... extraction current sensor 40 ... pure water pump 41 ... pure water tank 42 ... pure water pipe line 43 ... Water level sensor 50 ... Compressor 51 ... Cathode outlet temperature sensor

Claims (11)

A fuel cell system comprising: a fuel cell that generates electricity by an electrode reaction between an anode and a cathode sandwiching an electrolyte membrane; a cooling system that circulates a coolant between the fuel cell and the radiator; and a fan that blows air to the radiator In the cooling control device,
Fan rotational speed limiting means for limiting the rotational speed of the fan;
A coolant temperature detecting means for detecting the temperature of the coolant;
When the detected coolant temperature exceeds the predetermined temperature threshold, and a restriction releasing means for releasing the rotational speed limit of the fan by the fan rotation speed limiting means,
According to the operating state of the fuel cell, which is one of the load of the fuel cell, the pure water tank water level, the cathode outlet air temperature, the output limit state of the fuel cell, and the deviation between the target output of the fuel cell and the output limit value The temperature control threshold value for canceling the rotational speed limit of the fan is changed . The operating state of the fuel cell is a load of the fuel cell,
2. The cooling control device for a fuel cell system according to claim 1, wherein the temperature range value is set to be higher as the load of the fuel cell is larger.   The cooling control apparatus for a fuel cell system according to claim 2, wherein the load of the fuel cell is an extraction current or an extraction electric power of the fuel cell.   The cooling control apparatus for a fuel cell system according to claim 2, wherein the load of the fuel cell is a target extraction current or a target extraction power of the fuel cell. An air conditioner serving as a load device of the fuel cell;
Air conditioner on / off detecting means for detecting whether the operating state of the air conditioner is on or off,
The load of the fuel cell indicates the operating state of the air conditioner,
The restriction release unit includes a first temperature threshold value in an air conditioner on state and a second temperature threshold value in an air conditioner off state, and the first temperature threshold value is set to a value higher than the second temperature threshold value. The cooling control device for a fuel cell system according to claim 2. A pure water tank for storing pure water for humidification of the fuel cell;
Comprising a tank water level detection means for detecting the water level of the pure water tank, a,
The operating state of the fuel cell is a pure water tank water level,
2. The cooling control apparatus for a fuel cell system according to claim 1, wherein the restriction release means sets a higher temperature threshold for releasing the fan rotation speed restriction as the tank water level is higher. A cathode outlet air temperature detecting means for detecting the cathode outlet air temperature;
The operating state of the fuel cell is the cathode outlet air temperature,
2. The cooling control apparatus for a fuel cell system according to claim 1, wherein the restriction release unit sets a lower temperature threshold value for releasing the fan speed restriction as the cathode outlet air temperature is higher. Output limiting means for limiting the output of the fuel cell according to the detected temperature of the coolant,
The operating state of the fuel cell is an output limiting state of the fuel cell,
2. The cooling control apparatus for a fuel cell system according to claim 1, wherein the restriction release means sets the temperature threshold value for releasing the fan rotation speed restriction so that the output restriction becomes tight. Output limiting means for limiting the output of the fuel cell according to the detected temperature of the coolant,
The operating state of the fuel cell is a deviation between the target output of the fuel cell and the output limit value,
2. The cooling of the fuel cell system according to claim 1, wherein the limit release unit sets a lower temperature threshold for releasing the fan rotation speed limit as the deviation between the target output of the fuel cell and the output limit value increases. Control device.   The said restriction cancellation | release means cancels | releases rotation speed limitation of a fan, when the detected coolant temperature exceeds a temperature threshold value for the predetermined time, The any one of Claims 1 thru | or 9 characterized by the above-mentioned. The fuel cell system cooling control device according to claim.   The restriction release means returns to the fan speed limit when the detected coolant temperature falls below a predetermined temperature threshold lower than the release temperature threshold for a predetermined time after canceling the fan speed limit. The cooling control device for a fuel cell system according to any one of claims 1 to 10.

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