JP2018088389A - Fuel cell system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to identify leakage of cooling water due to a failure of a radiator, etc., at an early stage.SOLUTION: A fuel cell system 1 includes: a first temperature sensor 81 that measures a temperature of cooling water at a cooling water outlet 12 side of a fuel cell 10; a second temperature sensor 82 that measures the temperature of the cooling water at a cooling water inlet 21 side of a water heater 20 for heating the cooling water; a third temperature sensor 83 that measures the temperature of the cooling water at a cooling water outlet 22 side of the water heater 20; a cooling water pump 50 that circulates the cooling water; and a control device 70. The control device is configured to determine that there is cooling water leakage when the condition: "a measurement temperature T1 measured by the first temperature sensor≠a measurement temperature T2 measured by the second temperature sensor" or the condition "no temperature difference ΔT between the measurement temperature T2 and a measurement temperature T3 measured by the third temperature sensor" is met.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a fuel cell system.

  Some conventional fuel cell systems detect cooling water leaks due to radiator breakage or the like based on fluctuations in power used by the cooling water pump. Further, a technique is disclosed in which a shortage of coolant in the fuel cell system is detected from an abnormality in the measurement results of the coolant temperature at the inlet and outlet of the coolant of the cooling water circulation pump and the coolant of the generator (for example, , See Patent Document 1).

JP 2014-058931 A

  However, it is difficult to detect a cooling water leak due to a radiator breakage at an early stage.

  In view of the above, an object of the present invention is to provide a fuel cell system that enables early detection of coolant leakage due to radiator breakage or the like.

A system according to an aspect of the present invention is a fuel cell system including a fuel cell,
A first temperature sensor for measuring the temperature of the cooling water on the cooling water outlet side of the fuel cell;
A second temperature sensor for measuring the temperature of the cooling water on the cooling water inlet side of the water heater for heating the cooling water;
A third temperature sensor for measuring the temperature of the cooling water on the cooling water outlet side of the water heater;
A cooling water pump for circulating cooling water;
A control device that receives measurement values from the first temperature sensor, the second temperature sensor, and the third temperature sensor, and controls driving of the cooling water pump and the water heater;
With
The water heater, the second temperature sensor, and the third temperature sensor are disposed above the cooling water pump and the first temperature sensor in the gravity direction,
In the case where “the measured temperature T1 by the first temperature sensor is not equal to the measured temperature T2 by the second temperature sensor”, or “the temperature between the measured temperature T2 and the measured temperature T3 by the third temperature sensor”. When there is no difference ΔT ”, it is determined that a cooling water leak has occurred.

  In this fuel cell system, when the water level is lowered to such an extent that the cooling water leaks and does not reach the water heater, there is no cooling water between the first temperature sensor and the second temperature sensor. Therefore, since a temperature difference occurs, it is possible to determine cooling water leakage by detecting the presence or absence of the temperature difference. Also, if there is no cooling water before and after the water heater along the flow direction of the cooling water (upstream side and downstream side), the heat of the heating element does not move and stays there, Even if the air is warmed, the heat of the heating element does not flow, and a temperature difference ΔT does not occur between the measurement temperature T2 and the measurement temperature T3. Therefore, the leakage of the cooling water is detected by detecting the presence or absence of the temperature difference. can do.

In the fuel cell system, the control device
"Measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor" or "There is no temperature difference ΔT between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor" ”Drive the cooling water pump at a higher speed,
When “measured temperature T1 = measured temperature T2” or “there is a temperature difference ΔT”, the control device is configured to determine that the coolant level is lower than the water heater and higher than the fuel cell and the coolant pump. It may be.

The fuel cell system further includes a cooling water radiator, and a fourth temperature sensor that measures the temperature of the cooling water on the cooling water outlet side of the radiator,
The control device
"Measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor" or "There is no temperature difference ΔT between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor" ”Drive the cooling water pump at a higher speed,
If “measurement temperature T1 = measurement temperature T2” or “there is a temperature difference ΔT” does not hold and “measurement temperature T1 = measurement temperature T4 measured by the fourth temperature sensor” is not established, the cooling water level is the cooling level. You may be comprised so that it may determine that it is lower than the height of a water pump.

The fuel cell system further includes a cooling water radiator, and a fourth temperature sensor that measures the temperature of the cooling water on the cooling water outlet side of the radiator,
The control device
"Measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor" or "There is no temperature difference ΔT between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor" ”Drive the cooling water pump at a higher speed,
After “measurement temperature T1 = measurement temperature T2” or “there is a temperature difference ΔT” is not established, after the power generation of the fuel cell is stopped, “measurement temperature T1 = measurement temperature by the fourth temperature sensor” When it is not “T4”, the cooling water level may be determined to be zero.

The fuel cell system further includes a cooling water radiator, and a fourth temperature sensor that measures the temperature of the cooling water on the cooling water outlet side of the radiator,
The control device
"Measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor" or "There is no temperature difference ΔT between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor" ”Drive the cooling water pump at a higher speed,
If “measurement temperature T1 = measurement temperature T2” or “there is a temperature difference ΔT” does not hold, and “measurement temperature T1 = measurement temperature T4 measured by the fourth temperature sensor”, the water level of the cooling water is It may be configured to determine that it is zero.

  ADVANTAGE OF THE INVENTION According to this invention, the fuel cell system which makes it possible to discover the cooling water leak by a radiator failure etc. at an early stage can be provided.

It is a figure which shows the outline of a structure of a fuel cell system. It is the figure seen from the side surface which shows the example of arrangement | positioning of the gravity direction, such as a water heater in a fuel cell system, and a fuel cell, and the example of the water level of cooling water. It is a flowchart which shows the example of determination of the water level of a cooling water. It is the figure seen from the side surface which shows the example of arrangement | positioning of the gravity direction, such as a water heater in a fuel cell system of 2nd Embodiment, and a water level level example of a cooling water. It is a flowchart which shows the example of determination of the water level of cooling water in 3rd Embodiment.

  A preferred embodiment of the present invention will be described with reference to the accompanying drawings. In addition, in each figure, what attached | subjected the same code | symbol has the same or similar structure.

[First Embodiment]
The fuel cell system 1 includes a fuel cell 10, a water pipe 60 through which cooling water of the fuel cell 10 flows, a radiator 40 installed in the water pipe 60, a bypass 62 of the water pipe 60, a three-way valve 30 installed in the water pipe 60, and the water pipe 60. An installed cooling water pump 50, a computer (control device), and the like are provided (see FIG. 1). The fuel cell system 1 of the present embodiment further includes a water heater 20, a first temperature sensor 81, a second temperature sensor 82, a third temperature sensor 83, a fourth temperature sensor 84, and the like (FIG. 1). reference).

  The bypass 62 is a bypass channel that branches from the water pipe 60 at the upstream side (upstream side) of the radiator 40. The three-way valve 30 can be used to adjust the flow rates to the radiator 40 side and the bypass 62 side.

  The water heater 20 is a heater for heating the cooling water, which is disposed at a position in the water tube 60 that is the rear stage (downstream side) of the fuel cell 10. A branch pipe 61 for water heating may be provided in the water pipe 60, and the water heater 20 may be provided in the branch pipe 61 (see FIG. 1). In this case, the cooling water may be sent to the branch pipe 61 and the water heater 20 only when necessary using the three-way valve 32 provided in the branch portion. The water heater 20 is disposed above the fuel cell 10 and the cooling water pump 50 in the gravity direction (vertical direction) (see FIG. 2).

  The radiator 40 is an air cooling device that releases heat of the cooling water using the radiator fans 43 and 44. Reference numeral 41 denotes a cooling water inlet of the radiator 40.

  The cooling water pump 50 is a pump for circulating the cooling water by applying pressure. The arrangement of the cooling water pump 50 is not particularly limited, but the cooling water pump 50 of this embodiment is arranged on the water pipe 60 between the cooling water outlet 42 of the radiator 40 and the cooling water inlet 11 of the fuel cell 10. (See FIG. 1). In addition, the cooling water pump 50 in this embodiment is arrange | positioned at the height equivalent to the fuel cell 10 (refer FIG. 2).

  The temperature sensors 81 to 84 are sensors that measure the water temperature at a predetermined position of the cooling water circulating through the fuel cell system 1.

  The first temperature sensor 81 is a sensor that measures the temperature of the cooling water on the cooling water outlet 12 side of the fuel cell 10.

  The second temperature sensor 82 is a sensor that measures the coolant temperature at the coolant inlet 21 side of the water heater 20. According to the second temperature sensor 82, the coolant temperature before being heated by the water heater 20 is measured.

  The third temperature sensor 83 is a sensor that measures the coolant temperature on the coolant outlet 22 side of the water heater 20. According to the third temperature sensor 83, the cooling water temperature after heating when heated by the water heater 20 is measured.

  The fourth temperature sensor 84 is a sensor that measures the coolant temperature at the coolant outlet 42 side of the radiator 40. According to the fourth temperature sensor 84, the coolant temperature after being cooled by passing through the radiator 40 is measured.

  Note that the second temperature sensor 82 and the third temperature sensor 83 in the present embodiment are located above the cooling water pump 50, the first temperature sensor 81, and the fuel cell 10 in the gravity direction, similarly to the water heater 20. Are arranged (see FIG. 2).

  The computer (control device) 70 controls the fuel cell 10, the three-way valve 30, the cooling water pump 50, and the like according to operating conditions. The computer 70 of the present embodiment receives the measured values of the water temperature by the first temperature sensor 81, the second temperature sensor 82, the third temperature sensor 83, and the fourth temperature sensor 84, and receives the cooling water pump 50 and the water. The driving of the heater 20 is controlled (see FIG. 1 and the like).

  Next, the cooling water leak detection function in the fuel cell system 1 of the present embodiment will be described using a flowchart (see FIG. 3).

  First, an outline of cooling water leak detection in the fuel cell system 1 will be briefly described. In the fuel cell system 1, when the water level is lowered to such an extent that the cooling water leaks and does not reach the water heater 20, the cooling water is interposed between the first temperature sensor 81 and the second temperature sensor 82. Since there is no temperature difference, a temperature difference ΔT occurs between the measured temperature T1 measured by the first temperature sensor 81 and the measured temperature T2 measured by the second temperature sensor 82, so that cooling water leaks by detecting the presence or absence of the temperature difference. Can be determined. Further, when there is no cooling water before and after (upstream and downstream) of the water heater 20 along the direction in which the cooling water flows, the temperature T2 measured by the second temperature sensor 82 and the third temperature sensor 83 are used. Since a temperature difference ΔT does not occur with the measured temperature T3, it is possible to detect a cooling water leak by detecting the presence or absence of this temperature difference.

In the present embodiment, the following four levels are set as the coolant level circulating in the fuel cell system 1 as a premise for detecting coolant leakage (see FIG. 2).
“Normal water level A (full)”: A normal water level at which the water level exceeds the water heater 20 or reaches the water heater 20.
・ "Abnormal water level B (mid)" ... An abnormal water level where the water level is below the water heater 20.
“Abnormal water level C (low)”: A further abnormal water level in which the water level is below the upper surface of the fuel cell 10 or the upper part of the cooling water pump 50.
・ "Abnormal water level D (empty)" …… The most abnormal water level where the water level is almost zero.

  Cooling water leak detection is performed as follows. First, the cooling water pump 50 is driven to rotate at a low speed, and the water heater 20 is heated (the heater is turned on to heat the cooling water) (step SP1). In addition, the low rotation as used in this specification means the rotation which assumed the minimum flow volume when flowing cooling water. That is, the number of rotations when the cooling water circulates in a situation where the force for pushing out the water is weak. The rotation speed of the present embodiment is such that cooling water is not leaking, cooling water is circulated when there is a sufficient amount of cooling water, cooling water is leaking, and cooling water is not circulated when cooling water is reduced. The number of revolutions.

  Here, “the measured temperature T1 by the first temperature sensor 81 ≠ the measured temperature T2 by the second temperature sensor 82” (if the coolant level is equal to or lower than B, the coolant is contained in the water heater 20). The measured temperature T2 measured by the second temperature sensor 82 that is not in contact with the cooling water is different from the measured temperature T1 measured by the first temperature sensor 81) or “measured temperature T2 and the third temperature sensor 83”. If there is no temperature difference ΔT between the measured temperature T3 and the measured temperature T3 (Yes in step SP2), the computer 70 determines that the coolant leaks in the fuel cell system 1. In this case, the process proceeds to step SP3 and subsequent steps, and the degree of cooling water leakage is determined.

  On the other hand, there is no temperature difference ΔT between “the measured temperature T1 by the first temperature sensor 81 ≠ the measured temperature T2 by the second temperature sensor 82” and “the measured temperature T2 by the third temperature sensor 83”. ”(No in step SP2), the computer 70 determines that no cooling water leak has occurred and the water level is normal (normal water level A) (step SP6), and cooling. The water leak detection flow is terminated.

  In step SP3, the cooling water pump 50 is driven to rotate at a high speed, and the water heater 20 is heated (step SP3). In addition, high rotation as used in this specification means rotation sufficient to make the heat generation of the fuel cell system 1 reach the radiator 40. In this embodiment, it is set as the rotation speed which can flow cooling water. If the cooling water can be allowed to flow even if air is contained by increasing the number of revolutions of the cooling water pump 50, the determination using the sensor can be performed.

  After a lapse of a predetermined time in step SP3 (the specific time is not limited as long as the temperature difference between T2 and T3 can be generated by the water heater 20), “measurement temperature T1 = measurement temperature T2”. Alternatively, it is determined whether or not “there is a temperature difference ΔT between the measured temperature T2 and the measured temperature T3” (step SP4-1). If Yes in step SP4-1, it is determined that the cooling water of the fuel cell system 1 is at the abnormal water level B (mid) (step SP9), and the cooling water leak detection flow is terminated. Incidentally, when there is extrusion of cooling water due to high rotation of the cooling water pump 50, a temperature difference ΔT occurs between the measurement temperature T2 and the measurement temperature T3. The height is high enough to allow extrusion. On the other hand, in the case of No in step SP4-1, the power generation of the fuel cell 10 is stopped (step SP4-2), and there is no heating element between the fourth temperature sensor 84 and the first temperature sensor 81. To. Thereafter, the process proceeds to step SP5.

  In step SP5, it is determined whether or not “measurement temperature T1 = measurement temperature T4”. If Yes in step SP5, this means that there is no temperature difference ΔT between the measured temperature T1 and the measured temperature T4. If water is present, the water flows from the fourth temperature sensor 84 toward the first temperature sensor 81, and the fuel cell 10 is not generating heat between them, so that the water rises in the fuel cell 10. Without being heated, the measurement temperature T4 and the measurement temperature T1 become the same temperature. From these results, it is determined that the cooling water of the fuel cell system 1 is at an abnormal water level C (low) that is lower than the height of the fuel cell 10, for example, so that the cooling water flows (step SP8). End the flow. The abnormal water level C (low) is a level at which the cooling water can be pushed out by the cooling water pump 50. Therefore, there is a movement of the cooling water from the fourth temperature sensor 84 to the first temperature sensor 81. The measurement temperature T1 and the measurement temperature T4 measured by the fourth temperature sensor 84 become the same temperature.

  On the other hand, in the case of No in step SP5, this means that there is a temperature difference ΔT between the measured temperature T1 and the measured temperature T4. If there is no water, no water flows through the first temperature sensor 81 and the fourth temperature sensor 84. At this time, the measurement temperature T1 is a temperature of the fuel cell 10 (stack), and the measurement temperature T4 is a different temperature such as a temperature affected by heat conduction from the piping of the radiator 40 body. And the measured temperature T4 become different temperatures. From these results, it is determined that the cooling water of the fuel cell system 1 is at the abnormal water level D (empty) (step SP7), and the cooling water leakage detection flow is terminated. The abnormal water level D (empty) is such that the cooling water runs out, and both the measured temperature T1 and the measured temperature T4 only capture the air temperature at that place.

  According to the fuel cell system 1 of the present embodiment described so far, according to the conventional method, the coolant leakage can be determined only when the coolant does not flow into the coolant pump, in other words, With the conventional method, it was not possible to find a cooling water leak until the cooling water was removed, but it was possible to find a cooling water leak due to a radiator breakage at an early stage.

  The embodiments described above are for facilitating the understanding of the present invention, and are not intended to limit the present invention. Each element provided in the embodiment and its arrangement, material, condition, shape, size, and the like are not limited to those illustrated, and can be appropriately changed. In addition, the structures shown in different embodiments can be partially replaced or combined.

  For example, in the above-described embodiment, the example in which the temperature sensors 82 and 83 are disposed at the cooling water inlet 21 and the cooling water outlet 22 of the water heater 20 has been described. This is only an example of a suitable arrangement. In short, in order to detect the cooling water leak in the fuel cell system 1, it is important to detect the temperature difference of the cooling water between the predetermined location of the water pipe 60 (or the branch pipe 61). If this can be achieved, the arrangement of the temperature sensor is not specified at a precise position.

  Further, the arrangement of the fuel cell 10, the cooling water pump 50, the first to fourth temperature sensors 81 to 84, etc. shown in the above-described embodiment is merely an example, and the fuel cell system arranged at a height different from this. 1 can also detect a coolant leak early based on the same mechanism and concept.

[Second Embodiment]
A second embodiment of the fuel cell system 1 will be described with reference to FIG. In the fuel cell system 1, the fuel cell 10 is disposed at a position higher than the cooling water pump 50. Further, the first temperature sensor 81 is arranged at the same height as the fuel cell 10, and the fourth temperature sensor 84 is arranged at a position lower than the fuel cell 10 and higher than the coolant pump 50 (see FIG. 4). ).

In such a fuel cell system 1, although detailed description is omitted, the level of the cooling water circulating in the fuel cell system 1 is determined according to the mechanism and concept described in the first embodiment.
“Normal water level A (full)”: The normal water level that the water level exceeds (has reached) the water heater 20.
・ "Abnormal water level B (mid)" ... An abnormal water level where the water level is below the water heater 20.
“Abnormal water level C (low)”: A further abnormal water level in which the water level is below the bottom surface of the fuel cell 10 or the upper part of the cooling water pump 50.
・ "Abnormal water level D (empty)" …… The most abnormal water level where the water level is almost zero.
It is possible to determine which of the following.

[Third Embodiment]
In the first embodiment described above, when the cooling water leak is detected, if the answer is No in step SP4-1 (when there is no temperature difference ΔT between the measured temperature T2 and the measured temperature T3), the fuel cell 10 generates power. Although stopped (step SP4-2), conversely, it is also possible to detect cooling water leakage without stopping the power generation of the fuel cell 10. Hereinafter, an example of determining the water level when the power generation of the fuel cell 10 is not stopped will be described (see FIG. 5). In addition, description is abbreviate | omitted about step SP11-step SP13, step SP16, step SP19 which is the same content as 1st Embodiment, and only the part of step SP14-step SP18 is demonstrated here (refer FIG. 5).

  In the case of No in step SP14, the process proceeds to step SP15 without stopping the power generation of the fuel cell 10. In step SP15, it is determined whether or not “measurement temperature T1 = measurement temperature T4”. In the case of No in step SP15, this means that there is a temperature difference ΔT between the measured temperature T1 and the measured temperature T4. If water is present, the water flows from the fourth temperature sensor 84 toward the first temperature sensor 81. Since the fuel cell 10 exists between them, the temperature of the water rises in the fuel cell 10, and the measured temperature T4 and measurement temperature T1 are different temperatures. From these results, it is determined that the cooling water of the fuel cell system 1 is at an abnormal water level C (low) that is lower than the height of the fuel cell 10, for example, so that the cooling water flows (step SP18). End the flow.

  On the other hand, if Yes in step SP15, there is no temperature difference ΔT between the measured temperature T1 and the measured temperature T4. If there is no water, water does not flow through the first temperature sensor 81 and the fourth temperature sensor 84, so the measurement temperature T1 and the measurement temperature T4 are the same. From these results, it is determined that the cooling water of the fuel cell system 1 is at the abnormal water level D (empty) (step SP17), and the cooling water leakage detection flow is terminated.

  The present invention is suitable for application to a fuel cell system.

DESCRIPTION OF SYMBOLS 1 ... Fuel cell system, 10 ... Fuel cell, 12 ... Cooling water outlet, 20 ... Water heater, 21 ... Cooling water inlet, 22 ... Cooling water outlet, 40 ... Radiator, 42 ... Cooling water outlet, 50 ... Cooling water pump , 70 ... Computer (control device), 81 ... First temperature sensor, 82 ... Second temperature sensor, 83 ... Third temperature sensor, 84 ... Fourth temperature sensor, T1 ... Measurement by the first temperature sensor Temperature, T2 ... Measured temperature by the second temperature sensor, T3 ... Measured temperature by the third temperature sensor, T4 ... Measured temperature by the fourth temperature sensor

Claims (5)

A fuel cell system having a fuel cell,
A first temperature sensor for measuring a temperature of cooling water on a cooling water outlet side of the fuel cell;
A second temperature sensor for measuring the temperature of the cooling water on the cooling water inlet side of the water heater for heating the cooling water;
A third temperature sensor for measuring a coolant temperature on the coolant outlet side of the water heater;
A cooling water pump for circulating cooling water;
A control device that receives measurement values from the first temperature sensor, the second temperature sensor, and the third temperature sensor, and controls driving of the cooling water pump and the water heater;
With
The water heater, the second temperature sensor, and the third temperature sensor are disposed above the cooling water pump and the first temperature sensor in the gravity direction,
In the case where “the measured temperature T1 by the first temperature sensor is not equal to the measured temperature T2 by the second temperature sensor”, or “the measured temperature T2 and the measured temperature T3 by the third temperature sensor”. The fuel cell system is configured to determine that a cooling water leak has occurred when there is no temperature difference ΔT. The controller is
When “measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor” or “a temperature between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor” When there is no difference ΔT ”, the cooling water pump is driven at a higher speed,
When “measured temperature T1 = measured temperature T2” or “there is the temperature difference ΔT”, the control device determines that the coolant level is lower than the water heater and higher than the fuel cell and the coolant pump. The fuel cell system according to claim 1, wherein the fuel cell system is configured to. A cooling water radiator, and a fourth temperature sensor for measuring the temperature of the cooling water on the cooling water outlet side of the radiator,
The controller is
When “measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor” or “a temperature between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor” When there is no difference ΔT ”, the cooling water pump is driven at a higher speed,
When “measurement temperature T1 = measurement temperature T2” or “there is a temperature difference ΔT” does not hold and “measurement temperature T1 = measurement temperature T4 measured by the fourth temperature sensor” is not established, the water level of the cooling water The fuel cell system according to claim 1, wherein the fuel cell system is configured to determine that is lower than a height of the cooling water pump. A cooling water radiator, and a fourth temperature sensor for measuring the temperature of the cooling water on the cooling water outlet side of the radiator,
The controller is
When “measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor” or “a temperature between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor” When there is no difference ΔT ”, the cooling water pump is driven at a higher speed,
When “measurement temperature T1 = measurement temperature T2” or “there is a temperature difference ΔT” is not established, power generation of the fuel cell is stopped, and then “measurement temperature T1 = measurement temperature T4 by the fourth temperature sensor”. When not, the fuel cell system according to claim 1, wherein the fuel cell system is configured to determine that the water level of the cooling water is zero. A cooling water radiator, and a fourth temperature sensor for measuring the temperature of the cooling water on the cooling water outlet side of the radiator,
The controller is
When “measured temperature T1 measured by the first temperature sensor ≠ measured temperature T2 measured by the second temperature sensor” or “a temperature between the measured temperature T2 and the measured temperature T3 measured by the third temperature sensor” When there is no difference ΔT ”, the cooling water pump is driven at a higher speed,
If “measurement temperature T1 = measurement temperature T2” or “there is a temperature difference ΔT” does not hold, and “measurement temperature T1 = measurement temperature T4 measured by the fourth temperature sensor”, the water level of the cooling water The fuel cell system according to claim 1, wherein the fuel cell system is configured to determine that the level is zero.

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