JP2004179153A - Fuel cell system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make an discharge circulating gas possible to be utilized to heat a heating medium without causing the boiling of the heating medium, high-pressurizing of the heating medium passage, and degeneration or the like of the heating medium. <P>SOLUTION: At a cold-start, the fuel cell system is warmed up by giving heat of a high-temperature combustion gas generated by a combustor 5 to the heating medium to control the temperature of the fuel cell system with a heat exchanger 6, and discharge is carried out via a gas discharge three-way valve 21 to discharge a high-temperature combustion gas generated by the combustor 5 without passing through the heat exchanger 6 in carrying out hydrogen purge. <P>COPYRIGHT: (C)2004,JPO

Description

  The present invention relates to a fuel cell device that can effectively remove a power generation suppressing substance that suppresses power generation.

  2. Description of the Related Art Conventionally, when a fuel gas such as hydrogen supplied to a fuel cell (hereinafter referred to as hydrogen) is circulated and supplied, an impurity that suppresses the generation of electric power, that is, a power generation suppressing substance is accumulated along with the circulating gas in a circulation path. There is known one that discharges to the atmosphere (see Patent Document 1).

This is because during a certain operation time when the amount of impurities in the circulation path is considered to exceed a predetermined amount, impurities are gradually accumulated and adhere to the electrode reaction surface due to the closed cycle of the circulation path, and the partial pressure of hydrogen is relatively high. When the electrochemical reaction is hindered due to a decrease in hydrogen and the output voltage of the fuel cell drops above a predetermined level, or when the hydrogen concentration drops below a predetermined level, the gas in the circulation path is released to the atmosphere. Release to the atmosphere by a valve.
JP 2000-243417 A

  However, in the above conventional example, when the amount of impurities in the circulation path is equal to or more than a predetermined value, the gas in the circulation path is released to the atmosphere, but the circulation path contains hydrogen having a low content in the atmosphere. For reasons such as, it is not preferable to discharge it as it is not a regulated substance, and when hydrogen is produced by reforming fuel such as methanol or gasoline, a small amount of hydrogen gas contains fuel components. In some cases, it is not preferable to release the substance as it is from the viewpoint of the atmospheric environment.

  Desirably, the gas in the circulation path is mixed with an oxidizing gas such as air, burned in a combustor or the like, and discharged in the form of water vapor or the like. By passing through the heat exchanger, it is conceivable to reuse the heat medium of the fuel cell for raising the temperature.

  In such a case, if the heat medium is flowing through the heat exchanger, the heat medium can be heated in a relatively small amount. However, when the heat medium does not flow on the heat exchanger side, the generated heat of combustion is given to a very small portion of the heat medium, and the temperature of the heat medium becomes high. It is necessary to consider that there is a possibility of causing a system failure due to the above or a deterioration due to thermal decomposition of the heat medium.

  Therefore, the present invention has been made in view of the above-described problems, and it is possible to use the exhaust circulating gas for heating the heat medium without causing the heat medium to boil, increasing the pressure of the heat medium passage, and altering the heat medium. It is intended to provide a battery system.

  According to a first aspect of the present invention, a gas in a hydrogen supply unit that supplies hydrogen to a fuel cell is discharged through a combustion gas generation unit by a hydrogen purge unit, and reacted with oxygen by the combustion gas generation unit to generate a high-temperature gas. In a fuel cell system in which a combustion gas is generated, and the heat of the combustion gas is supplied to a heat medium that controls the temperature of the fuel cell system by a heat exchange means during a cold start and heated to warm up the fuel cell system, A heat exchange means bypass means for discharging the gas without passing through the heat exchange means is provided, and when performing hydrogen purging, the combustion gas is discharged by bypassing the heat exchange means.

  According to a second aspect of the present invention, a gas in a hydrogen supply unit that supplies hydrogen to a fuel cell is discharged through a combustion gas generation unit by a hydrogen purge unit, and a high-temperature combustion gas is generated by the combustion gas generation unit. At the time of cold start, the fuel cell system can be warmed up by applying heat of the combustion gas to the heat medium by the heat exchange means and heating it, and the heat medium passage switching means closes the heat medium passage to the heat exchange means side. Alternatively, in the fuel cell system in which the heat medium is passed to the heat exchange unit bypass passage side in which the heat medium is passed by bypassing the heat exchange unit, even when the heat medium passage is set to the heat exchange unit bypass passage side, the predetermined amount is set to the heat exchange unit side. The heat medium was also circulated.

  According to a third aspect of the present invention, a gas in a hydrogen supply unit for supplying hydrogen to a fuel cell is discharged through a combustion gas generation unit by a hydrogen purge unit, and is reacted with oxygen by the combustion gas generation unit to generate a high-temperature gas. It is possible to warm up the fuel cell system by generating combustion gas and applying heat of the combustion gas to a heat medium for controlling the temperature of the fuel cell system by a heat exchange means at the time of a cold start, thereby heating the fuel cell system. In a fuel cell system comprising a heat exchange means bypass passage for bypassing the heat medium and flowing the heat medium and a heat medium passage switching means for switching the heat medium passage to the heat exchange means side or the heat exchange means bypass passage side, hydrogen purge is required. If the heat medium is flowing through the heat exchange means bypass passage at the time of the heat exchange, the heat medium passage is switched to the heat exchange means and the hydrogen purge is performed. It was.

  Therefore, according to the first aspect of the present invention, at the time of a cold start, the heat of the high-temperature combustion gas generated by the combustion gas generation means is given to the heat medium for controlling the temperature of the fuel cell system by the heat exchange means and heated. In order to discharge the hot combustion gas generated by the combustion gas generating means without passing through the heat exchanging means through the heat exchanging means bypass means, the hydrogen purging is performed. The generated heat is discharged to the atmosphere without being supplied to the heat exchanger, and even when the flow of the heat medium into the heat exchanger is stopped, part of the heat medium is not overheated, It is possible to avoid problems such as boiling, high pressure of the heat medium passage, and deterioration of the heat medium.

  In the second invention of the present invention, the gas in the hydrogen supply means for supplying hydrogen to the fuel cell is discharged through the combustion gas generation means by the hydrogen purge means, and the combustion gas generation means generates high-temperature combustion gas. At the time of cold start, the fuel cell system can be warmed up by applying heat of the combustion gas to the heat medium by the heat exchange means and heating it, and the heat medium passage switching means closes the heat medium passage to the heat exchange means side. Alternatively, in the fuel cell system in which the heat medium is passed to the heat exchange unit bypass passage side in which the heat medium is passed by bypassing the heat exchange unit, even when the heat medium passage is set to the heat exchange unit bypass passage side, the predetermined amount is set to the heat exchange unit side. Since the heat medium is also allowed to flow through the heat exchanger, a predetermined amount of the heat medium always flows through the heat exchanger during the operation of the combustor, even during the normal operation in which the warming-up is completed. Body boiling, high pressure of the heat medium passage, it is possible to avoid problems such as deterioration of the heat medium.

  According to the third aspect of the present invention, the gas in the hydrogen supply means for supplying hydrogen to the fuel cell is discharged through the combustion gas generation means by the hydrogen purge means, and is reacted with oxygen by the combustion gas generation means to generate a high-temperature gas. It is possible to warm up the fuel cell system by generating combustion gas and applying heat of the combustion gas to a heat medium for controlling the temperature of the fuel cell system by a heat exchange means at the time of a cold start, thereby heating the fuel cell system. In a fuel cell system comprising a heat exchange means bypass passage for bypassing the heat medium and flowing the heat medium and a heat medium passage switching means for switching the heat medium passage to the heat exchange means side or the heat exchange means bypass passage side, hydrogen purge is required. When the heat medium was flowing through the heat exchange means bypass passage side when the heat exchange was performed, the heat medium passage was switched to the heat exchange means side, and then hydrogen purging was performed. The heat generated by the hydrogen purging is removed by a large amount of heat medium through the heat exchange means, and the heat medium can be boiled without increasing the work of the pump, the pressure of the heat medium passage is increased, and the heat medium is deteriorated. Troubles can be avoided.

  Hereinafter, the fuel cell system of the present invention will be described based on each embodiment.

(1st Embodiment)
1 to 4 show a first embodiment of a fuel cell system to which the present invention is applied. FIG. 1 is a system configuration diagram, FIG. 2 is a control block diagram, and FIG. 3 is a control flowchart of "heating operation execution determination means". FIG. 4 is a control flowchart of the "heating operation means".

  In FIG. 1, a fuel cell system includes a fuel cell 1 that generates electric power by receiving supply of hydrogen and oxygen (air), a hydrogen supply system 2 as a hydrogen supply unit that circulates and supplies hydrogen to the fuel cell 1, and a fuel cell system. An oxidizing gas supply system 3 for supplying air containing oxygen to the cell 1; a heat medium supply system 4 as a temperature control means for supplying a heat medium to the fuel cell 1; It comprises a combustor 5 as a combustion gas generating means for burning, and a heat exchanger 6 as a heat exchange means for exchanging heat between the combustion gas of the combustor 5 and the heat medium. A temperature sensor 7 for detecting the temperature of the fuel cell 1 and a wattmeter 8 for detecting a power generation state of the fuel cell 1 are arranged in the fuel cell 1, and both detection signals are input to the control unit 9.

  The hydrogen supply system 2 supplies hydrogen as a fuel gas from a high-pressure storage tank (not shown) to a fuel electrode of the fuel cell 1 after reducing the pressure to a preset pressure by a hydrogen pressure regulating valve 10. Exhaust hydrogen discharged from the fuel electrode of the fuel cell 1 is returned through the circulation passage 11, mixed with hydrogen newly supplied by the ejector 12, and supplied to the fuel electrode of the fuel cell 1 again. The circulation path 11 is connected to the combustor 5 via a purge valve 13 as a purge means. When the purge valve 13 is opened, the gas in the circulation path 11 is supplied to the combustor 5. The hydrogen pressure regulating valve 10 and the purge valve 13 are controlled by the control unit 9.

  The oxidizing gas supply system 3 takes in the outside air, compresses and sends it out by a compressor 14 driven by an electric motor (not shown), supplies it to the oxidant electrode of the fuel cell 1, and discharges the exhaust air discharged from the oxidant electrode to the combustion Is supplied to the vessel 5.

  The heat medium supply system 4 controls the temperature of the fuel cell 1 by flowing the heat medium through a heat medium passage (not shown) of the fuel cell 1. The heat medium whose flow rate is controlled by the control unit 9 is supplied to the heat medium supply system 4. A pump 16 for pressure feeding and a radiator 18 for cooling a heat medium discharged from the fuel cell 1 via a three-way valve 17 are connected in series to a heat medium passage of the fuel cell 1. The radiator 18 is provided with a radiator fan 19, the rotation of which is controlled by the control unit 9 to control the amount of air flow to the radiator 18, thereby controlling the temperature of the heat medium passing through the radiator 18.

  The three-way valve 17 is arranged at a branch point to a heat exchange passage 20 that bypasses the radiator 18, and allows the heat medium discharged from the fuel cell 1 to flow through the heat exchange passage 20, or a heat exchanger. 6 is switched to the radiator 18 side which bypasses, or is switched and selected by the control unit 9. Assuming that the heat exchange passage 20 is the main passage, the passage on the radiator 18 side is a heat exchanger bypass passage. A heat exchanger 6 as heat exchange means is disposed in the middle of the heat exchange passage 20, and the heat exchanger 6 can heat a heat medium passing therethrough as described later. The heat exchanger 6 is disposed in the heat exchanger passage 20 through which the heat medium does not always flow without being disposed in the heat medium supply system 4 through which the heat medium always flows by the pump 16. Pressure loss due to the heat exchanger 6 does not always occur in the circulation, and a decrease in efficiency due to the pump 16 constantly performing useless work is prevented.

  The control unit 9 controls switching of the three-way valve 17 based on a temperature signal from the temperature sensor 7 of the fuel cell 1. When the temperature signal from the temperature sensor 7 is higher than a predetermined temperature, the three-way valve 17 is switched to the radiator 18 side (heat exchanger bypass passage), and the heat medium is guided to the radiator 18 and cooled. The set temperature is appropriately determined from a temperature range in which the fuel cell system can operate stably. When the temperature signal from the temperature sensor 7 is lower than the set temperature, the three-way valve 17 is switched to the heat exchange passage 20, and the heat medium is guided to the heat exchanger 6.

  In the heat exchanger 6, a heat medium is supplied to one of the heat exchange surfaces, and the combustion gas from the combustor 5 is selectively supplied to the other of the heat exchange surfaces via the exhaust three-way valve 21. Is supplied to the heat medium to perform heat exchange. As described above, the heat medium supplied to the heat exchanger 6 through the heat exchange passage 20 is lower than the set temperature, and the heat medium is heated to increase the temperature of the fuel cell 1. . The case where the heat medium is lower than the set temperature corresponds to the case where the temperature of the fuel cell 1 is low and the power generation is impossible or the efficiency is very poor.

  When the purge valve 13 is opened, the combustor 5 burns the circulating gas discharged from the circulation path 11 with the exhaust air from the oxidizing gas supply system 3 of the fuel cell 1 and passes through the exhaust three-way valve 21. To exhaust the combustion gas to the outside air or supply it to the heat exchanger 6. The switching position of the exhaust three-way valve 21 is controlled by the control unit 9, and is usually located at an outside air side where the combustion gas is discharged to the outside air. The three-way valve 17 of the heat medium supply system 4 is connected to the heat exchanger 6. When it is switched to the heat exchanger side, it is switched to the heat exchanger side position. When the exhaust three-way valve 21 is switched to the position on the heat exchanger side and the combustion gas of the combustor 5 is supplied to the heat exchanger 6, the heat medium is heated by the heat of the combustion gas. In addition, while the purge valve 13 is open, the circulating gas of the fuel electrode of the fuel cell 1 is discharged, and power generation in the fuel cell 1 is not performed.

  The fuel cell system having the above configuration is controlled by the control block diagram of FIG.

  In FIG. 2, the control unit 9 first determines whether or not to perform the heating operation on the heat medium by the heating operation execution determination unit 25, and then performs the heating operation or the heating operation by the heating operation unit 26 according to the determination result. And the continuation of the normal operation is executed. FIG. 3 is a flowchart of the heating operation execution determining means 25, and FIG. 4 is a flowchart of the heating operation means 26. Hereinafter, a detailed control procedure of each means will be described with reference to FIGS.

  First, the heating operation execution determining means shown in FIG. 3 reads the temperature TFC of the fuel cell 1 from the temperature signal TFC from the temperature sensor 7 in step S11.

  In step S12, it is determined whether or not the read temperature signal TFC is higher than a predetermined temperature SLTFC. If the temperature signal TFC is higher than the predetermined temperature SLTFC, the process proceeds to step S14, and if not, the process proceeds to step S13.

  In step S13, the heating operation flag FCOLD is set to 1 (heating operation permission), and the flow ends, and in step S14, the heating operation flag FCOLD is set to 0 (heating operation not permitted), and the process ends.

  The heating operation means shown in FIG. 4 first determines in step S21 whether the heating operation flag FCOLD set by the heating operation execution determination means is 1 or 0. If so, the process proceeds to step S22.

  In step S24, the exhaust gas three-way valve 21 is set to the outside air side position, and a series of processing ends.

  In step S22, in order to perform the heating operation, the purge valve 13 is opened, and the hydrogen pressure regulating valve 10 is adjusted so that the amount of heat necessary for warming up is supplied from the combustor 5 with a sufficient amount of hydrogen. The operation of the compressor 14 is continued to supply air to the vessel 5. Thus, the combustor 5 is supplied with a sufficient amount of hydrogen and air to generate heat required for warming up, and generates high-temperature combustion gas. Further, the three-way valve 17 of the heat medium supply system 4 is switched to the heat exchanger 6 side, and the pump 16 is operated. The heat medium flows through the pump 16, the fuel cell 1, the three-way valve 17, the heat exchange passage 20, and the heat exchanger 6. After these processes, the process proceeds to step S23.

  In step S23, the exhaust three-way valve 21 is switched to the heat exchanger side position, and a series of processing ends. The high-temperature combustion gas obtained in the combustor 5 passes through the heat exchanger 6. The heat of the combustion gas is transmitted to the heat medium via the heat exchanger 6, and the high-temperature heat medium is guided to the fuel cell 1. Therefore, the temperature of the fuel cell 1 is rapidly increased, and reaches a temperature at which the fuel cell 1 can operate efficiently in a short time.

  In the above processing, the present application is characterized by step S23 and step S24. That is, the combustion gas is guided to the heat exchanger 6 only when the heating operation is performed, and the combustion gas is discharged to the atmosphere without passing through the heat exchanger 6 otherwise. Can be prevented from being transmitted to the heat medium, and overheating and boiling of the heat medium, breakage due to high pressure of the heat medium passage, deterioration of the heat medium, and the like can be suppressed.

  In the present embodiment, the following effects can be obtained.

  (A) At the time of a cold start, heat of the high-temperature combustion gas generated by the combustor 5 as the combustion gas generating means is given to the heat medium for controlling the temperature of the fuel cell system by the heat exchanger 6 as the heat exchange means. The three-way exhaust valve 21 as a heat exchange means bypass means for heating the fuel cell system by heating and discharging the high-temperature combustion gas generated by the combustor 5 without passing through the heat exchanger 6 when executing the hydrogen purge. The heat generated during the hydrogen purge is discharged to the atmosphere without being supplied to the heat exchanger 6, so that even when the flow of the heat medium into the heat exchanger 6 is stopped, Since the portion is not overheated, troubles such as boiling of the heat medium, high pressure of the heat medium passage, and deterioration of the heat medium can be avoided.

(2nd Embodiment)
5 to 8 show a second embodiment of the fuel cell system to which the present invention is applied, FIG. 5 is a system configuration diagram, FIG. 6 is a control block diagram, FIG. 7 is a control flowchart of "hydrogen purge determination means", FIG. 8 is a control flowchart of the "hydrogen purging means". In this embodiment, a part of the heat medium is always circulated to the heat exchanger, and the exhaust three-way valve downstream of the combustor 5 is eliminated, so that the entire amount of combustion gas in the combustor is supplied to the heat exchanger. It is like that. The same devices as those of the previous embodiment are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In FIG. 5, the fuel cell system connects the heat exchanger 6 and the three-way valve 17 in the heat exchange passage 20 of the heat medium supply system 4 to the vicinity of the heat medium outlet of the fuel cell 1, and the controller 9 A bypass valve 27 whose valve opening is adjusted is arranged and provided. A part of the heat medium discharged from the fuel cell 1 flows into the heat exchange passage 20 according to the opening degree of the bypass valve 27, is sucked into the pump 16 via the heat exchanger 6, and Distribute. Although not shown, the same operation can be performed by operating the three-way valve 17 itself without providing the bypass valve 27 so that the heat medium flows through the heat exchange passage 20.

  Further, the combustor 5 is directly connected to the heat exchanger 6, and when the combustor 5 burns the circulating gas, the entire amount of the combustion gas is supplied to the heat exchanger 6.

  At the time of the cold start in the present embodiment, the exhaust hydrogen and the exhaust air supplied via the purge valve 13 are burned by the combustor 5 as in the first embodiment, and the high-temperature combustion gas is removed by the heat exchanger. 6 On the other hand, the three-way valve 17 is open on the heat exchanger 6 side, and the entire flow rate of the heat medium from the outlet of the fuel cell 1 is supplied from the three-way valve 17 to the heat exchanger 6. For this reason, at the time of a cold start, the fuel cell system can be warmed up by applying heat of the combustion gas to the heat medium and heating it.

  Further, in the fuel cell system, impurities are accumulated in a gas in a circulation path which is a hydrogen supply means 2 for supplying hydrogen to the fuel cell 1, and this gas is used as a combustor as the combustion gas generation means. The control described below is performed in connection with the operation of the purge valve 13 as the hydrogen purging means discharged through the fuel cell 5.

  FIG. 6 is a control block diagram executed at regular intervals by the control unit 9 of the fuel cell system having the above-described configuration. The control unit 9 first determines whether or not to perform hydrogen purging by the hydrogen purge determining unit 28, and then performs the hydrogen purging operation by the hydrogen purging unit 29 according to the determination result, or Continue normal operation without executing hydrogen purge. FIG. 7 is a flowchart of the hydrogen purge judging means 28, and FIG. 8 is a flowchart of the hydrogen purge means 29. The detailed control procedure of each means will be described below with reference to FIGS.

  First, in step S31, the hydrogen purge determination unit 28 shown in FIG. 7 determines whether the hydrogen purge permission flag FH2P is 1 (permit hydrogen purge) or 0 (permit hydrogen purge). If the hydrogen purge permission flag FH2P is 1, the hydrogen purge control is already underway, so there is no need to determine whether to perform hydrogen purge. The process is terminated as it is, and if the hydrogen purge permission flag FH2P is 0, the process proceeds to step S32. move on.

  In step S32, it is determined whether or not the "impurity accumulation index contained in the circulating gas in the circulation path" SUMGAS calculated later exceeds a predetermined value SLGAS. If the “accumulation index of impurities contained in the circulating gas” “SUMGAS” is equal to or less than the predetermined value SLGAS, it is determined that hydrogen purging is not necessary yet, and the process proceeds to step S33.

  In step S35, the "impurity accumulation index contained in the circulating gas in the circulation path" SUMGAS is set to zero, and the hydrogen purge permission flag FH2P is set to 1 to permit the hydrogen purge operation in order to permit the hydrogen purge.

  In step S33, the power generation amount W of the fuel cell 1 is read, and the process proceeds to step S34.

In step S34, the following equation is given.
Calculates the “index of accumulation of impurities contained in the circulating gas in the circulation path” SUMGAS, and ends the processing. Here, K is, for example, K = 1 if this processing is performed every second, and if irregular, it is a numerical value proportional to the time from the last execution of this processing to the current time. Should be set.

  With this setting, the “index of accumulation of impurities contained in the circulating gas in the circulation path” SUMGAS is a value substantially proportional to the integrated value of the extracted electric power. Although the value of the impurity accumulation index SUMGAS is different from the actual impurity amount, the impurity of the hydrogen electrode is substantially proportional to the amount of electric power taken out similarly to SUMGAS. By judging the hydrogen purge timing based on the magnitude of the accumulation index "SUMGAS", it is possible to estimate the exact purge timing without waste. Note that the timing of the hydrogen purge is not limited to the method described in this embodiment, and as disclosed in Japanese Patent Application Laid-Open No. 2000-243417, every time a certain operation time elapses, the impurities are circulated in a closed cycle. Therefore, when the electrochemical reaction is hindered due to gradually accumulating and adhering to the electrode reaction surface or the relative partial pressure of the fuel gas is reduced, and the output voltage of the fuel cell is reduced to a predetermined value or more, Alternatively, the prediction may be made when the hydrogen concentration falls below a predetermined concentration.

  The hydrogen purging means 29 shown in FIG. 8 first determines in step S41 whether the hydrogen purge permission flag FH2P is 1 (hydrogen purge permission). If the hydrogen purge permission flag FH2P is 1, the flow proceeds to step S42. The process proceeds, and if the hydrogen purge is not permitted, the present process is terminated as it is.

  In step S42, the rotational speed NP of the pump 16 is read, and in step S43, the opening BBO of the bypass valve 27 corresponding to the rotational speed NP of the pump 16 is read with reference to the pump rotational speed-opening table, and in step S44. The bypass valve 27 is opened by the read opening BBO, and the purge valve 13 is opened to start purging.

  In step S45, the timer TM is increased by a predetermined amount T (a value that recovers the operation of the system and minimizes unnecessary release of hydrogen, which is experimentally obtained). The predetermined amount T is the same as K in step S34 of FIG. 7, and may be a constant value if the present process is performed at regular intervals, but if the process is irregular, it may be a predetermined value from the previous execution of the present process to the present. Set a value proportional to the elapsed time. By doing so, the time during which the purge is being performed can be accurately counted up.

  In step S46, it is determined whether or not the timer TM has exceeded a predetermined value SLTM. If the timer TM has not exceeded the predetermined value SLTM, the process is terminated to continue purging. If it has, the process proceeds to step S47 to terminate the hydrogen purge. Therefore, the bypass valve 27 and the purge valve 13 are closed, the hydrogen purge permission flag FH2P is set to zero, the timer TM is set to zero for the next measurement, and the process ends.

  The characteristic part of the present embodiment is the processing of steps S42 to S44. When hydrogen purging is performed, the three-way valve 17 is on the radiator 18 side, that is, on the side of the heat exchanger bypass passage as heat exchange means. Even though the heat medium always flows through the heat exchanger 6 in a predetermined amount (based on the pump rotation speed-opening degree table in step 43), excessive heat is not given to a part of the heat medium, , Boiling of the heat medium passage, high pressure of the heat medium passage, and deterioration of the heat medium due to thermal decomposition can be avoided. When the three-way valve 17 was on the heat exchanger 6 side, the control of the bypass valve 27 was unnecessary, but there was no problem even if it was executed, and the cases were not divided for simplification.

  Further, in the present embodiment, the bypass valve 27 is newly added. However, the three-way valve 17 is provided with an opening adjustment function, and a predetermined amount of the heat medium is also circulated to the heat exchanger 6 side during the hydrogen purging. With this configuration, the same effect can be obtained without requiring the addition of the bypass valve 27.

  In the present embodiment, the following effects can be obtained.

  (A) The gas in the hydrogen supply means 2 for supplying hydrogen to the fuel cell 1 is discharged through the combustor 5 as the combustion gas generating means by the purge valve 13 as the hydrogen purging means, and the high temperature combustion is performed by the combustor 5. The fuel cell system can be warmed up by generating gas and applying heat of the combustion gas to the heat medium by the heat exchanger 6 as a heat exchange means at the time of a cold start to heat the fuel cell system. In the fuel cell system in which the heat medium passage is circulated by the three-way valve 17 to the heat exchanger 6 side or the heat exchange means bypass passage side in which the heat medium is circulated by bypassing the heat exchanger 6, Even when the heat exchanger is on the bypass passage side, a predetermined amount of the heat medium is circulated also to the heat exchanger 6 side. A predetermined amount of the heat medium flows through the heat exchanger 6, so that the heat medium boils and the high pressure of the heat medium passage is increased without newly adding the exhaust three-way valve 21 and the like between the combustor 5 and the heat exchanger 6. Troubles such as heat generation and deterioration of the heat medium can be avoided.

(Third embodiment)
9 to 12 show a third embodiment of a fuel cell system to which the present invention is applied. FIG. 9 is a system configuration diagram, FIG. 10 is a control block diagram, and FIG. 11 is a control flowchart of a "heat medium passage selecting means". FIG. 12 is a control flowchart of the "hydrogen purging means". In the present embodiment, the purging operation is performed after the three-way valve switches the heat medium to flow to the heat exchanger. Note that the same devices as those in FIGS. 1 to 8 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  9, the fuel cell system has a configuration in which the bypass valve 27 is removed from the fuel cell system shown in FIG. Prior to the purging operation, the control unit 9 switches the three-way valve 17 to the heat exchanger side.

  FIG. 10 is a control block diagram executed at regular intervals by the control unit 9 of the fuel cell system configured as described above. The control unit 9 first determines whether or not hydrogen purging is to be performed by the hydrogen purge determining means 28. When the hydrogen purging is permitted, the heat medium passage selecting means 30 transfers the heat medium to the heat exchanger 6 side. Then, hydrogen purge control is performed by the hydrogen purge means 31. The hydrogen purge determination means 28 is the same as that in FIG. 7 of the second embodiment, and has already been described, and thus description thereof will be omitted. FIG. 11 is a control flowchart of the heat medium passage selecting unit 30, and FIG. 12 is a control flowchart of the hydrogen purge unit 31. The detailed control procedure of each means will be described below with reference to FIGS.

  The heat medium passage selecting means 30 shown in FIG. 11 first determines whether or not the hydrogen purge permission flag FH2P is 1 (hydrogen purge permission) in step S51, and if not, proceeds to step S52 and is permitted. If yes, go to step 55.

  In step S52, the temperature TFC of the fuel cell 1 is read from the temperature signal of the temperature sensor 7, and in step S53, it is determined whether the temperature TFC is lower than a predetermined temperature SLTFC. This processing is ended in the mode for cooling the heat medium on the radiator 18 side. On the other hand, if the temperature TFC is lower than the set temperature SLTFC, the process proceeds to step S55.

  Step S55 is selected irrespective of the temperature of the fuel cell 1 when hydrogen purging is permitted in step S51, and when the temperature TFC is lower than the set temperature SLTFC in step S53. This mode is set to a mode in which the heat medium is circulated to the heat exchanger 6 on the side of the heat exchanger 6, and the present process is ended. With this control, the heat medium always flows through the heat exchanger 6 when the hydrogen purge is executed.

  The hydrogen purging means 31 shown in FIG. 12 first determines whether or not the hydrogen purge permission flag FH2P is 1 (hydrogen purge permission) at step S61. If so, the process proceeds to step S62.

  In step S62, the purge valve 13 is opened to start hydrogen purging. In step S63, the timer TM is set to a predetermined amount T (a value that recovers the operation of the system and minimizes wasteful hydrogen release). , Required experimentally). This is the same as K in step S34 in FIG. 7, and may be a constant value if this processing is performed at regular intervals, but if irregular, the elapsed time from the previous execution of this processing to the present time Set a value proportional to. By doing so, the time during which the purge is being performed can be accurately counted up.

  In step S64, it is determined whether or not the timer TM has exceeded a predetermined value SLTM. If the timer TM has not exceeded the predetermined value SLTM, the process is terminated to continue purging, and if it has, the process proceeds to step S65 to terminate the hydrogen purge. Therefore, the purge valve 13 is closed, the hydrogen purge permission flag FH2P is set to zero, the timer TM is set to zero for the next measurement, and the process ends.

  By performing the above processing, even if the heat medium passage is on the radiator 18 side (heat exchange means bypass passage side), the hydrogen purge is performed after the change to the heat exchanger 6 side. Part of the heat medium does not stay in the inside, so that it is possible to avoid boiling of the heat medium, increase in the pressure of the heat medium passage, and deterioration due to thermal decomposition of the heat medium.

  In addition, it becomes possible to combine the combustor 5 for raising the temperature of the fuel cell 1 at the time of low-temperature start-up and the combustor 5 for burning the hydrogen discharged by the purge with one, so that the layout property and the cost can be reduced.

  In the present embodiment, the following effects can be obtained.

  (C) The gas in the hydrogen supply means 2 for supplying hydrogen to the fuel cell 1 is discharged by the hydrogen purge valve 13 through the combustor 5 serving as combustion gas generation means, and the combustor 5 reacts with oxygen to cause high temperature. During the cold start, the heat of the combustion gas is given to a heat medium for controlling the temperature of the fuel cell system by the heat exchanger 6 as a heat exchange means and heated to warm up the fuel cell system. Hydrogen purging is required in a fuel cell system which includes a three-way valve 17 as a heat medium passage switching means for switching a heat medium passage to a heat exchanger 6 side or a heat exchanger bypass passage (radiator 18) side. When the heat medium is flowing through the heat exchanger bypass passage at the time of the heat transfer, the heat medium passage is switched to the heat exchanger 6 side and then the hydrogen purge is performed. The generated heat is taken away by a large amount of heat medium via the heat exchanger 6, without adding a new exhaust three-way valve or the like between the combustor 5 and the heat exchanger 6. Troubles such as boiling of the heat medium, high pressure of the heat medium passage, and deterioration of the heat medium can be avoided without increasing the work.

(Fourth embodiment)
13 and 14 show a fourth embodiment of a fuel cell system to which the present invention is applied. FIG. 13 is a control block diagram, and FIG. 14 is a control flowchart of "hydrogen purging means". In the present embodiment, based on the system configuration shown in FIG. 9 of the third embodiment, if the heat medium flows through the radiator when the hydrogen purge is requested, the heat medium is transferred to the heat exchange means. Purging is prohibited until it is distributed. The same devices as those in FIGS. 1 to 12 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  The fuel cell system has the system configuration shown in FIG. 9 of the third embodiment.

  FIG. 13 is a control block diagram executed by the control unit 9 of the fuel cell system at regular intervals. The control unit 9 first determines whether or not hydrogen purging is to be performed by the hydrogen purge determining means 28. When the hydrogen purging is permitted, the heat medium passage selecting means 30 transfers the heat medium to the heat exchanger 6 side. Then, hydrogen purge control is performed by the hydrogen purge unit 32, and the timing of the hydrogen purge unit 32 is changed in accordance with an instruction from the heat medium passage selection unit 30. The hydrogen purge determination means 28 is the same as that of FIG. 7 of the second embodiment, and the heat medium passage selection means 30 is the same as that of FIG. 11 of the third embodiment, which has already been described. Is omitted. FIG. 14 is a control flowchart of the hydrogen purge means 32. Hereinafter, a detailed control procedure of the hydrogen purge unit 32 will be described with reference to FIG.

  The hydrogen purging means 32 shown in FIG. 14 first determines whether or not the hydrogen purge permission flag FH2P is 1 (hydrogen purge permission) in step S71. If not, the flow proceeds to step S77, and the hydrogen purge means is permitted. If so, the process proceeds to step S72.

  In step S72, referring to the direction in which the three-way valve is open, if the valve is open on the radiator 18 side, that is, on the heat exchanger bypass passage side, the process proceeds to step S77, and the valve is opened on the heat exchanger 6 side. If so, the process proceeds to step S73.

  In step S73, the purge valve 13 is opened to start purging, and steps S74 to S76 are executed. Note that the processing in steps S74 to S76 is the same as that in steps S63 to S65 in FIG. 12 of the third embodiment, and a duplicate description will be omitted.

  On the other hand, in step S77, the purge valve 13 is closed, and the process is terminated in a purge prohibited state.

  By executing the above processing, if the three-way valve 17 is opened on the radiator 18 side and the heat medium is not flowing to the heat exchanger 6, the process proceeds from step S72 to step S77 and the purge valve 13 is turned on. Since the valve is closed, it is possible to avoid boiling of the heat medium, increasing the pressure of the heat medium passage, and altering the heat medium due to thermal decomposition. Also, if the heat medium passage becomes the radiator 18 side (heat exchanger bypass passage side) during the purging, the purging is prohibited at that time and the value of the timer TM is kept at the current value until the purging is completed. , The purge time is also performed accurately. And it is consumed by the subsequent purge.

  In the present embodiment, in addition to the effect (C) in the third embodiment, the following effects can be obtained.

  (D) If the heat medium is flowing through the heat exchange means bypass passage (radiator 18 side) when the hydrogen purge is requested, purging is prohibited until the heat medium flows to the heat exchanger 6 side. In addition, it is possible to avoid boiling of the heat medium, increase in the pressure of the heat medium passage, deterioration of the heat medium, and the like.

(Fifth embodiment)
FIGS. 15 and 16 show a fifth embodiment of a fuel cell system to which the present invention is applied. FIG. 15 is a system configuration diagram, and FIG. 16 is a control flowchart of a heat medium passage selecting means. In the present embodiment, a heat medium quenching means for quenching the temperature of the heat medium faster than usual is provided, and when the heat medium is circulated to the radiator side at the time of requesting hydrogen purge, the heat medium is cooled by the heat medium quenching means. After rapid cooling, a heat medium is circulated to the heat exchanger side to perform hydrogen purging. The same devices as those in FIGS. 1 to 14 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In FIG. 15, the fuel cell system is almost the same as the system configuration shown in FIG. 9 of the third embodiment, but measures the temperature of the heat medium at the outlet of the radiator 18 and inputs the temperature signal to the control unit 9. The configuration in which the heat medium thermometer 33 is provided is added.

  Although not shown, the control unit 9 of the fuel cell system includes a control block similar to that shown in FIG. 13 of the fourth embodiment, and first determines whether or not to perform hydrogen purging by the hydrogen purge determining means 28. Then, when execution of hydrogen purging is permitted, the heat medium is circulated to the heat exchanger 6 side by the heat medium passage selecting means 30, and then hydrogen purge control is executed by the hydrogen purging means 32. The timing is changed according to an instruction from the heat medium passage selecting means 30.

  The hydrogen purge determination means 28 is the same as that of FIG. 7 of the second embodiment, and the hydrogen purge means 32 is the same as that of FIG. 14 of the fourth embodiment, and has already been described. I do. FIG. 16 is a control flowchart of the heat medium passage selecting means 30. The detailed control procedure of the heat medium passage selecting means 30 will be described below with reference to FIG.

  The heat medium path selecting means 30 shown in FIG. 16 first reads the fuel cell temperature TFC in step S81, and determines in step S82 whether the fuel cell temperature TFC is higher than the low set temperature SLTFCL. The process proceeds to S92, and if it is higher, the process proceeds to step S83.

  In step S92, the three-way valve is set to the heat exchanger 6 side to set the mode in which the fuel cell 1 is not cooled, and the process ends.

  In step S83, the three-way valve is set to the radiator 18 (heat exchanger bypass passage) side to prepare for cooling the fuel cell 1.

  In step S84, it is determined whether or not the hydrogen purge permission flag FH2P is 1 (permit hydrogen purge). If permitted, the process proceeds to step S91. In step S91, the rotation speed of the pump 16 is set to the first predetermined rotation speed (normally). The rotation speed is set to a second predetermined rotation speed higher than the rotation speed of the pump during operation, and the radiator fan 19 is rotated. With this setting, a large amount of the cold heat medium cooled by the radiator 18 is sent to the fuel cell 1 and the fuel cell 1 can be rapidly cooled.

  On the other hand, if hydrogen purging is not permitted in step S84, the rapid cooling operation is not performed and normal control is performed. That is, in step S85, it is determined whether the temperature TFC of the fuel cell 1 is higher than the high set temperature SLTFCH higher than the low set temperature SLTFCL, and if it is higher, the rotation speed of the pump 16 is set to the first predetermined rotation speed in step S90. The second predetermined rotation speed is set to a higher value, but if it is lower, the first predetermined rotation speed is set.

  Thereafter, in step S87, the heat medium temperature TLLC is read from the temperature signal from the temperature sensor 33, and it is determined in step S88 whether the temperature is lower than the predetermined medium temperature SLTLLC. 19 is rotated.

  By performing the above processing, even if the temperature of the fuel cell 1 is high and the three-way valve 17 opens the radiator 18 to the side where the heat medium flows, the fuel cell 1 is rapidly cooled and the fuel cell 1 is cooled. After sufficiently lowering the temperature, open the three-way valve 17 to the heat exchanger 6 side and then perform hydrogen purging, thereby avoiding boiling of the heat medium, increasing the pressure of the heat medium passage, and alteration due to thermal decomposition of the heat medium. It is possible to do. Further, there is an advantage that the temperature of the fuel cell 1 can be prevented from becoming too high, and that the time during which the hydrogen purging is prohibited is short.

  In the present embodiment, the following effects can be obtained in addition to the effect (C) in the third embodiment and the effect (D) in the fourth embodiment.

  (E) As a fuel cell system, a radiator 18 as a heat medium cooling means for cooling the heat medium to the heat exchange means bypass passage (radiator 18 side) and a heat medium quenching means for rapidly cooling the temperature of the heat medium faster than usual. In the case where the radiator fan 19 is provided and the heat medium is flowing through the radiator 18 when the hydrogen purge is requested, the heat medium is rapidly cooled to a predetermined temperature or less by the radiator fan 19, and then the heat medium passage is connected to the heat exchanger. Since the hydrogen purging is performed after switching to the 6 side, the temperature of the fuel cell 1 is maintained at an optimum level, and the hydrogen purging is not hindered at an appropriate time. Deterioration of the heat medium can be avoided.

  (F) Since the pump 16 for increasing the flow rate of the heat medium passing through the radiator 18 is used as the heat medium quenching means, the fuel cell 1 can be accurately cooled without adding a special device.

  (G) The fuel cell system includes the radiator 18 in the heat exchange unit bypass passage, and the radiator fan 19 that increases the amount of air passing through the radiator 18 as the heat medium quenching unit. It is possible to do.

(Sixth embodiment)
17 to 19 show a sixth embodiment of the fuel cell system to which the present invention is applied. FIG. 17 is a control flowchart of the hydrogen purge determining means, FIG. 18 is a control flowchart of the heat medium passage selecting means, and FIG. 6 is a control flowchart of a purge unit. In the present embodiment, when the heat medium is flowing through the radiator when the hydrogen purge is requested, the heat medium is switched to the heat exchanger according to the urgency of the purge, and then the hydrogen purge is performed. Or prohibition of purging. The same devices as those in FIGS. 1 to 16 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  The fuel cell system has the system configuration shown in FIG. 15 of the fifth embodiment.

  Although not shown, the control unit 9 of the fuel cell system includes a control block similar to that shown in FIG. 13 of the fourth embodiment. When the execution of hydrogen purging is permitted, the heat medium is passed to the heat exchanger 6 by the heat medium passage selecting means 30, and then the hydrogen purging control is executed by the hydrogen purging means 32. FIG. 17 is a control flowchart of the hydrogen purge determining means 28, FIG. 18 is a control flowchart of the heat medium passage selecting means 30, and FIG. 19 is a control flowchart of the hydrogen purge means 32. A detailed control procedure of each means will be described below.

  The hydrogen purge determination means 28 shown in FIG. 17 first reads the current electric energy from the wattmeter 8 in step S101 and also reads the hydrogen purge duration time TM counted by the hydrogen purge means 32 described later.

In step S102, the following equation is obtained: SUMGAS = SUMGAS + W × K1-TM × K2
The SUMGAS, which is an impurity accumulation index, is calculated by the following equation. This index quantifies the fact that when the fuel cell is operated, electric power W is generated, so that impurities also accumulate, and when the purge is performed, the purge execution time increases, and the impurities decrease. Here, K1 and K2 are set by investigating appropriate values through experiments and the like.

  In step S103, it is determined whether the impurity accumulation index SUMGAS has become larger than the first predetermined value SLGASL. If it is larger, the process proceeds to step S104 to request a purge. In step S104, the first purge permission flag FH2PL is set to 1 and the second purge permission flag FH2PH is set to 0.

  In step S105, it is determined whether the impurity accumulation index SUMGAS has become larger than the second predetermined value SLGASH which is larger than the first predetermined value SLGASL. If it is larger, the second purge permission flag FH2PH is set to 1 and the first purge permission flag FH2PL is set to 0 in step S106 to request a purge.

  In step S107, it is determined whether or not the impurity accumulation index SUMGAS has fallen below zero, and if it has fallen below zero, it is determined that purging has been completed. In step S108, the first and second purge permission flags are both set to zero to prohibit purging. The process ends.

  By performing the above processing, the amount of impurities currently accumulated is at a level that requires urgent purging (SUMGAS> SLGASH) or at a level at which it is possible to wait until the heat medium passage is on the heat exchanger side. (SLGASH ≧ SUMGAS> SLGASL) or whether the purge is completed (0> SUMGAS).

  The heat medium passage selecting means 30 shown in FIG. 18 first determines whether or not the second purge permission flag FH2PH is 1 in step S111, and executes 1 if it is 1 (an urgently required purge state). In step S123, the three-way valve 17 is set to the heat exchanger 6 side so that the heat medium flows through the heat exchanger 6, and the process ends. If the second purge permission flag FH2PH = 0, the process proceeds to step S112.

  In step S112, the temperature TFC of the fuel cell 1 is read, and in step S113, it is determined whether the temperature TFC is higher than a predetermined temperature SLTFCL. If the temperature is low, the three-way valve 17 is set to the heat exchanger 6 side in step S123 so that the temperature of the fuel cell 1 is not further cooled. If the temperature is high, the three-way valve 17 is set to the radiator 18 side to cool the heat medium temperature in step S114. I do.

  In step S115, it is determined whether the first purge permission flag FH2PL is 1. If it is 1, the process proceeds to step S119, and if it is 0, the process proceeds to step S116. The processing of steps S116 to S122 is the same as the processing of steps S85 to S89 in FIG. 16 of the fifth embodiment, and a duplicate description will be omitted.

  By performing the above-described processing, when urging is urgently required and when the temperature of the fuel cell 1 is lower than the predetermined temperature SLTFCL, the three-way valve 17 is opened to the heat exchanger 6 side, and the fuel cell 1 is opened. The temperature is prevented from lowering any more, and in other cases, the pump 16 is rotated and / or the radiator fan 19 is rotated to actively cool.

  In the hydrogen purging means 32 shown in FIG. 19, first, in step S131, it is determined whether or not the second purge permission flag FH2PH is 1, and if it is 1, the routine jumps to step S134 to execute the hydrogen purge urgently and the purge valve The valve 13 is opened, the hydrogen purge duration time TM is counted up in step S135, and the process is terminated. On the other hand, if the second purge permission flag FH2PH = 0 in step S131, the process proceeds to step S132.

  In step S132, it is determined whether the first purge permission flag FH2PL is 1. If it is not 1, the purge is not requested. Therefore, the hydrogen purge duration time TM is reset in step S136, and the purge valve 13 is closed in step S137. Then, the present process ends. If FH2PL = 1 in step S132, the process proceeds to step S133.

  In step S133, it is determined whether the three-way valve 17 is set on the radiator 18 side, that is, in the heat exchanger bypass passage. If the three-way valve 17 is on the radiator 18 side, the purge valve 13 is closed in step S137 to delay the purge execution timing. The process is terminated and the present process ends. On the other hand, if the three-way valve 17 is on the heat exchanger 6 side, purging is possible. Therefore, the purge valve 13 is opened in step S134, the hydrogen purge continuation time TM is counted up in step S135, and the process is terminated.

  By performing the above processing, when urging is urgently required, even if the temperature of the fuel cell 1 is higher than the predetermined temperature SLTFCL, the heat medium can be circulated to the heat exchanger 6 side so that the heat exchanger 6 In the case where the purge is required while cooling and the fuel cell 1 can be operated without purging, the purge can be prohibited and the cooling of the fuel cell 1 can be prioritized. It is possible to avoid the boiling of the heat medium, the high pressure of the heat medium passage, the deterioration of the heat medium due to the thermal decomposition, and the like, while achieving the optimal balance between the temperature control of the fuel cell 1 and the fuel cell 1. Further, since the urgency of the purge can be predicted from the voltage drop of the cells constituting the fuel cell 1, the urgency of the purge may be determined based on the cell voltage, or may be used in combination.

  In the present embodiment, in addition to the effect (c) of the third embodiment, the effect (d) of the fourth embodiment, and the effects (f) and (g) of the fifth embodiment, the following effects are obtained. be able to.

  (H) If the heat medium is flowing through the heat exchange means bypass passage (radiator 18) when the hydrogen purge is requested, the hydrogen purge should be performed after switching the heat medium passage to the heat exchanger 6 side. In order to select whether to prohibit the purging in accordance with the urgency of the purging, the deviation from the optimal timing of the hydrogen purging and the deviation from the target of the request for switching the heat medium passage to the radiator 18 side are both minimized. Boiling of the medium, increase in the pressure of the heat medium passage, deterioration of the heat medium, and the like can be avoided.

  (G) When the urgency of the requested hydrogen purge is high, the heat medium passage is switched to the heat exchanger 6 side to perform the hydrogen purge, so that the hydrogen purge is executed without largely deviating from the optimal timing of the hydrogen purge. Therefore, it is possible to avoid boiling of the heat medium, increase in the pressure of the heat medium passage, deterioration of the heat medium, and the like without greatly lowering the power generation efficiency.

  (G) If the urgency of the hydrogen purging decreases during execution of the hydrogen purging, the heat medium passage is switched to the heat exchange means bypass passage (radiator 18) and the hydrogen purging is prohibited, so that the heat medium passage is moved to the radiator 18 side. It is possible to avoid boiling of the heat medium, increase in the pressure of the heat medium passage, deterioration of the heat medium, and the like while minimizing the deviation of the switching request from the target.

  (C) If the urgency of the requested hydrogen purge is low, the purging is prohibited, so that the deviation of the request for switching the heat medium passage toward the radiator 18 from the target is minimized while the boiling of the heat medium and the heat medium passage It is possible to avoid high pressure, deterioration of the heat medium, and the like.

  (G) As a fuel cell system, a heat medium cooling means for cooling the heat medium in the heat exchange means bypass passage, for example, a heat medium delivery pump 16 passing through the radiator 18 and a heat medium quenching for rapidly cooling the temperature of the heat medium. A means for operating a radiator fan 19 for sending cooling air to the radiator 18 as means is provided. When the urgency of the required hydrogen purge is low, the hydrogen purge is temporarily prohibited and the heat medium is cooled by the heat medium quenching means. After rapid cooling to a temperature below the temperature, the heat medium passage is switched to the heat exchanger 6 and then the hydrogen purge is permitted, so that the temperature of the fuel cell 1 can be set to the optimum temperature, and the purge timing is set to the optimum timing. To minimize boiling of the heat medium, increase the pressure of the heat medium passages, and alter the quality of the heat medium while minimizing the decrease in power generation efficiency. It can be.

  (S) Since the urgency of the purge is determined according to any of the cell voltage of the fuel cell 1, the operating time of the fuel cell 1, the operating load of the fuel cell 1, and the purge duration of the fuel cell 1, The degree of urgency can be accurately grasped.

(Seventh embodiment)
20 to 25 show a seventh embodiment of the fuel cell system to which the present invention is applied, FIGS. 20 to 23 show a first example of the seventh embodiment, and FIGS. 24 and 25 show a seventh embodiment. It is a 2nd Example of a form. In the present embodiment, the minimum opening degree of the three-way valve according to the pump discharge flow rate is ensured so that the flow rate of the heat medium (coolant) to the heat exchanger into which the entire amount of the combustion gas of the purged exhaust hydrogen flows into the combustor flows. Is set.

  FIG. 20 showing the first embodiment is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit, and FIGS. 21 and 22 are control block diagrams of pump control and three-way valve control executed by the control unit. 23 is a characteristic diagram showing an operation state of the heat medium supply system by the pump control and the three-way valve control. The same devices as those in FIGS. 1 to 19 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In FIG. 20, the heat medium supply system 4 of the fuel cell system is similar to the second embodiment in that the heat medium supply system 4 includes a heat exchanger passage 20 between the heat exchanger 6 and the three-way valve 17 and the fuel cell 1 And a three-way valve 17 whose valve opening is adjusted by the controller 9 is arranged and provided. A part of the heat medium discharged from the fuel cell 1 flows into the heat exchanger passage 20 in accordance with the opening degree of the three-way valve 17, is sucked into the pump 16 via the heat exchanger 6, and is absorbed by the heat exchanger 6. Distribute. In the heat medium supply system 4, the three-way valve 17 itself is operated without providing a bypass valve to operate the heat medium to flow through the heat exchange passage 20. The illustration of the hydrogen supply system 2 and the oxidizing gas supply system 3 is omitted.

  Further, the combustor 5 is directly connected to the heat exchanger 6, and when the combustor 5 burns the exhausted hydrogen circulating gas purged and discharged from the fuel cell 1 side, the entire amount of the combustion gas is transferred to the heat exchanger 6. The supplied combustion exhaust gas is cooled by the coolant in the heat exchanger 6 and then discharged outside the vehicle. The flow rate of the coolant flowing through the heat exchanger 6 is controlled by adjusting the opening of the three-way valve 17 by the control unit 9.

  The control unit 9 calculates the target flow rate of the heat medium to be supplied to the fuel cell 1 by the coolant target flow rate setting means 44 and calculates the target rotation rate calculated by the pump control means 45 based on the target flow rate. To control. The control unit 9 also calculates the valve opening of the three-way valve 17 to the heat exchange passage 20 by the three-way valve temperature control opening calculating means 46 based on the inlet temperature of the cooling liquid of the fuel cell 1. The minimum required opening of the three-way valve 17 is calculated by the three-way valve minimum opening calculating means 33 based on the target flow rate from the target flow rate setting means 44, and the three-way valve opening setting means is calculated based on the two opening degree calculating means 46 and 33. 34 controls the opening of the three-way valve 17.

  As shown in FIG. 21, the coolant target flow rate setting means 44 includes a target flow rate map in which the fuel cell output power and the coolant target flow rate are set in advance. The target flow rate of the coolant supplied to the fuel cell 1 is calculated with reference to the target flow rate map. In the target flow rate map, since the calorific value of the fuel cell 1 increases as the power taken out of the fuel cell 1 increases, the target flow rate of the coolant is increased to suppress an increase in the inlet / outlet temperature difference of the fuel cell 1 and The radiator 18 is set to improve the heat radiation characteristics.

  The pump control means 45 is provided with a pump flow rate / rotation speed map set in advance, and refers to a pump flow rate / rotation speed map to determine a pump rotation speed for achieving a target flow rate from the coolant target flow rate setting means 44. Then, the target rotation speed of the pump 16 is calculated, and the pump 16 is driven to reach the target rotation speed. The pump flow rate / rotation speed map is set by actually measuring the relationship between the pump rotation speed and the coolant flow rate in advance, or by predicting the relationship between the characteristics of the pump 16 and the pressure loss of the coolant circulation path.

  As shown in FIG. 22, the three-way valve temperature control opening calculating means 46 calculates the difference between the cooling water inlet temperature of the fuel cell 1 detected by the temperature detecting means 35 and a preset fuel cell inlet target coolant temperature. In accordance therewith, the opening of the three-way valve 17 for controlling the temperature of the fuel cell 1 is calculated. That is, when the detected coolant inlet temperature is higher than the inlet target coolant temperature, the flow rate to the heat exchanger passage 20 is reduced, and the three-way valve 17 is increased so that the flow rate to the radiator 18 is increased. When the opening degree is calculated and the detected coolant inlet temperature is lower than the inlet target coolant temperature, the flow rate to the heat exchange passage 20 is increased, and the flow rate to the radiator 18 is reduced instead. The opening degree of the three-way valve 17 is calculated, and if the difference between the two temperatures is smaller than the preset temperature difference, the calculation is performed so as to maintain the current valve opening degree of the three-way valve 17.

  FIGS. 23A to 23C show the opening of the three-way valve 17 at each target flow rate when the target flow rate is, for example, 100 L / min, 50 L / min, and 20 L / min. 3) shows the coolant flow rate distribution characteristics of the radiator side flow rate (solid line illustration, the flow rate is the vertical axis) and the bypass side flow rate (heat exchange passage 20 side, chain line illustration) according to the above.

  The three-way valve minimum required opening degree calculating means 33 calculates a predetermined target flow rate (for example, 5 liters per minute (5 L / min)) to the heat exchanger passage 20 by a predetermined target flow rate-three-way valve. An opening degree map is provided, and the minimum required opening degree of the three-way valve 17 is calculated with reference to the target flow rate-three-way valve opening degree map in accordance with the target flow rate of the cooling liquid output by the coolant target flow rate setting means 44. The target flow rate-three-way valve opening degree map sets how much the three-way valve 17 needs to be opened in order to secure the minimum required flow rate with respect to the changing target flow rate, and sets the degree of opening (%). First, an opening degree that can secure the minimum necessary flow rate for each flow rate is actually measured and set.

  In the examples of FIGS. 23A to 23C, in order to secure the minimum required flow rate, when the target flow rate is 100 L / min, the opening of the three-way valve 17 needs to be 3%, and the target flow rate is When the flow rate is 50 L / min, the opening degree of the three-way valve 17 is required to be 8%, and when the target flow rate is 20 L / min, the opening degree of the three-way valve 17 is required to be 15%.

  The three-way valve opening setting means 34 controls the opening of the three-way valve 17 from the three-way valve temperature adjustment opening calculating means 46 for adjusting the temperature of the coolant flowing into the fuel cell 1 and the minimum opening to the heat exchange passage 20. The minimum required opening of the three-way valve from the three-way valve minimum required opening calculating means 33 for ensuring the required flow rate is compared, the larger opening is selected, and the opening of the three-way valve 17 becomes the target opening. Drive.

  Although the three-way valve minimum required opening calculating means 33 of the above embodiment sets the minimum required opening of the three-way valve 17 based on the target flow rate from the coolant target flow rate setting means 44, it is not shown, It is also possible to measure the pump discharge flow rate and set the minimum required opening of the three-way valve 17 according to the pump discharge flow rate.

  As described above, in this (first) embodiment, the heat exchanger 6 for recovering the combustion heat of the combustion gas from the combustor 5 of purged hydrogen is provided in the heat exchange passage 20 on the radiator bypass side. In the fuel cell system, the minimum opening of the three-way valve is adjusted according to the pump discharge coolant flow rate (coolant target flow rate) so as to secure the coolant flow rate to the heat exchange passage 20 via the heat exchanger 6. This setting prevents the temperature of the coolant passing through the heat exchanger 6 from excessively rising and deteriorating the coolant, and ensures that the combustion exhaust gas of the combustor 5 is cooled by the heat exchanger 6 to the outside of the vehicle. Exhaust can be performed, and furthermore, it is possible to prevent the heat exchanger 6 from being broken in an empty firing state.

  FIGS. 24 and 25 are a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit showing a second example of the fuel cell system of the seventh embodiment, and a three-way valve minimum required opening calculating means. It is a control block diagram. In the fuel cell system shown in the present (second) embodiment, the minimum required opening of the three-way valve calculated by the three-way valve minimum required opening calculating means is based on the target flow rate of the coolant target flow rate setting means in the first embodiment. Instead of performing the calculation, the calculation is performed based on the pump target rotation speed calculated by the pump control means. 20 to 23 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In the present (second) embodiment, as shown in FIG. 24, the three-way valve minimum necessary opening degree calculating means 36 receives the pump target rotation speed calculated by the pump control means 45.

  As shown in FIG. 25, the three-way valve minimum required opening calculating means 36 is configured to calculate the minimum required opening of the three-way valve 17 based on the input target pump speed (or pump drive duty ratio). are doing. Specifically, the target for calculating the target coolant flow rate to the fuel cell 1 is provided before the three-way valve minimum required opening calculating unit 36B configured similarly to the three-way valve minimum required opening calculating means 33 of the first embodiment. A coolant flow rate calculation unit 36A is newly inserted.

  The target coolant flow rate calculation unit 36A includes a preset pump speed (or pump drive duty ratio) -coolant flow rate table, and is based on an input target pump speed (or pump drive duty ratio). The target coolant flow rate to the fuel cell 1 is calculated with reference to the pump rotation speed-coolant flow rate table, and is output to the three-way valve minimum required opening calculation section 36B. Other configurations are the same as in the first embodiment.

  Also in this (second) embodiment, the fuel cell system provided with the heat exchanger 6 for recovering the combustion heat of the combustion gas from the combustor 5 of the purged hydrogen in the heat exchanger passage 20 on the radiator bypass side. In order to secure the flow rate of the coolant to the heat exchanger passage 20 via the heat exchanger 6, the flow rate of the coolant discharged from the pump is determined from the pump rotation speed or the duty ratio of the pump drive. Since the minimum required opening of the valve 17 is set, it is possible to prevent the temperature of the coolant passing through the heat exchanger 6 from excessively increasing and to prevent the coolant from deteriorating. Thus, it is possible to reliably cool and exhaust the gas to the outside of the vehicle, and further, it is possible to prevent the heat exchanger 6 from being broken due to an empty firing state.

  In the present embodiment, in addition to the effect (A) in the second embodiment, the following effects can be obtained.

  (C) In the first embodiment, the heat medium supply means 4 includes a pump 16 for circulating the coolant of the fuel cell 1, and the heat medium passage switching means includes a passage 20 for passing the heat medium through the heat exchange means 6. The control means 9 controls the opening degree of the three-way valve to the heat exchange means passage passage 20 necessary for controlling the temperature of the fuel cell 1. The three-way valve temperature control opening calculating means 46 for calculating and the three-way valve 17 for calculating the minimum necessary opening of the three-way valve 17 in accordance with the pump discharge medium flow rate in order to secure the minimum necessary heat medium flow rate to the heat exchange means 6. The three-way valve opening calculated by the valve minimum required opening calculating means 33 and the three-way valve temperature control opening calculating means 46 is less than the minimum required opening calculated by the three-way valve minimum necessary opening calculating means 33. If necessary, set the three-way valve opening to the minimum required opening. A three-way valve opening setting means 34 for setting, and configured with a.

  That is, the heat exchanger passage 20 on the radiator bypass side is provided with a heat exchanger 6 for recovering the combustion heat of the combustion gas of the purged hydrogen by the combustor 5. Since the minimum opening of the three-way valve is set in accordance with the pump discharge coolant flow rate (coolant target flow rate) so as to secure the coolant flow rate, the coolant temperature via the heat exchanger 6 rises excessively and cooling is performed. The liquid can be prevented from deteriorating, and the combustion exhaust gas of the combustor 5 can be reliably cooled by the heat exchanger 6 and exhausted to the outside of the vehicle. Can be prevented.

  (G) In the second embodiment, the three-way valve minimum required opening calculating means 33 of the first embodiment calculates the minimum required opening of the three-way valve 17 based on the pump speed or the pump drive duty ratio. I made it. That is, the heat exchanger passage 20 on the radiator bypass side is provided with the heat exchanger 6 for recovering the combustion heat of the combustion gas of the purged hydrogen by the combustor 5. Through the heat exchanger 6 to obtain the pump discharge coolant flow rate from the pump rotation speed or the pump drive duty ratio so as to secure the coolant flow rate, and to set the three-way valve minimum opening according to the pump discharge coolant flow rate. It is possible to prevent the coolant temperature that has been excessively increased and the coolant from deteriorating, and the combustion exhaust gas of the combustor 5 can be reliably cooled by the heat exchanger 6 and exhausted to the outside of the vehicle. It is possible to prevent the exchanger 6 from being broken due to an empty firing state.

(Eighth embodiment)
26 to 27 show an eighth embodiment of a fuel cell system to which the present invention is applied, FIG. 26 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit, and FIG. FIG. 4 is a control block diagram of a three-way valve control unit to be used. In the present embodiment, when the hydrogen in the circulation path of the hydrogen supply means of the fuel cell is not purged, the entire amount of the heat medium (cooling liquid) flows to the radiator side, and the purged heat is supplied to the heat exchange passage at or immediately before the purge. The three-way valve is controlled so as to flow the minimum necessary flow rate. 20 to 25 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  As shown in FIG. 26, in the fuel cell system according to the present embodiment, a purge signal from the controller 9 is input to the three-way valve opening degree setting means 37.

  As shown in FIG. 27, the three-way valve opening setting means 37 includes a three-way valve opening degree for controlling the coolant temperature from the three-way valve temperature adjustment opening degree calculating means 46 and a three-way valve minimum required opening degree A select high output for selecting (select high) the opening with the larger minimum required opening and outputting the three-way valve opening for controlling the coolant temperature from the three-way valve temperature adjustment opening calculating means 46. A temperature control output. When the purge signal is not input, the temperature control output is selected and output as the three-way valve target opening, and when the purge signal is input, the select high output is selected and the three-way valve target opening is selected. There is provided a selection means 38 for outputting, and drives the three-way valve 17 so that the opening thereof becomes the target opening.

  As described above, in the present embodiment, when there is no purge signal, the three-way valve opening required for controlling the temperature of the fuel cell 1 is selectively output, and when there is the purge signal, the three-way valve minimum required opening is And the larger three-way valve opening required for controlling the temperature of the fuel cell 1 is selected and output, so that at the time of purging, the coolant temperature via the heat exchanger 6 rises excessively and the cooling The liquid can be prevented from deteriorating, and the combustion exhaust gas of the combustor 5 can be reliably cooled by the heat exchanger 6 and exhausted to the outside of the vehicle. Can be prevented. On the other hand, during most of the period during which the purge operation is not performed, the three-way valve 17 can be controlled to the opening degree required for controlling the temperature of the fuel cell 1. The cooling performance of the fuel cell 1 can be maintained at an optimum temperature.

  In the present embodiment, in addition to the effect (A) in the second embodiment, the following effects can be obtained.

  (T) The three-way valve opening setting means 37 sets the three-way valve opening to the minimum required opening at or immediately before purging by the purging means when the three-way valve opening is less than the minimum required opening. For this reason, at the time of purging, it is possible to prevent the temperature of the coolant passing through the heat exchanger 6 from excessively increasing and to prevent the coolant from deteriorating, so that the combustion exhaust gas of the combustor 5 is reliably cooled by the heat exchanger 6. The heat exchanger 6 can be prevented from being damaged due to being in an empty burning state. On the other hand, during most of the period during which the purge operation is not performed, the three-way valve 17 can be controlled to the opening degree required for controlling the temperature of the fuel cell 1. The cooling performance of the fuel cell 1 can be maintained at an optimum temperature.

(Ninth embodiment)
FIGS. 28 and 29 show a ninth embodiment of a fuel cell system to which the present invention is applied. FIG. 28 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit. FIG. 4 is a control block diagram of a three-way valve control unit to be used. In the present embodiment, the minimum required opening of the three-way valve is increased according to the purge time. 20 to 27 are denoted by the same reference numerals, and the description thereof will be omitted or simplified.

  As shown in FIG. 28, in the fuel cell system according to the present embodiment, a purge signal from the controller 9 is input to the three-way valve minimum required opening calculating means 39.

  As shown in FIG. 29, the three-way valve minimum required opening calculating unit 39 is input with a three-way valve minimum required opening calculating unit 39A (same configuration as shown in FIG. 25 of the seventh embodiment). A coefficient generation unit 39B that outputs a coefficient that increases according to the input time (purge time) of the purge signal, and a coefficient generation unit 39B that outputs a three-way valve minimum required opening signal output by the three-way valve minimum required opening calculation unit 39A A multiplier 39C for multiplying the output coefficient.

  The coefficient generator 39B does not generate a coefficient or outputs a coefficient “0” when no purge signal is input, and outputs a coefficient “1” when a purge signal is input. When the signal elapses a preset time, it is configured to output a coefficient “1” or more that increases according to the elapsed time.

  Therefore, the three-way valve minimum required opening calculating unit 39A outputs the coefficient output from the coefficient generator 39B to “none” or “0” when the purge signal is not input. When the multiplier 39C multiplies the three-way valve minimum required opening signal output from the controller 39 by the multiplier 39C, the minimum required opening is output as "zero". When the purge signal is input, the coefficient generator 39B outputs a coefficient “1”. Therefore, the three-way valve minimum required opening signal output from the three-way valve minimum required opening calculating section 39A is multiplied by the multiplier 39C. Is multiplied by the coefficient “1” and output as it is.

  Further, when the purge signal elapses a preset time, a coefficient of “1” or more that increases in accordance with the elapsed time is output, and is output by the three-way valve minimum required opening calculating section 39A. The three-way valve minimum required opening signal is multiplied by a coefficient of "1" or more by a multiplier 39C, and the increased minimum required opening is output. The output of the three-way valve minimum necessary opening calculating means 39 is input to the three-way valve opening setting means 34, and is compared with the three-way valve opening for controlling the coolant temperature from the three-way valve temperature adjusting opening calculating means 46. The larger opening is selected as the target opening (select high), and the opening of the three-way valve 17 is driven to be the target opening.

  As described above, in the present embodiment, when there is no purge signal, the three-way valve opening required for controlling the temperature of the fuel cell 1 is selectively output, and when there is the purge signal, the three-way valve minimum required opening is And the three-way valve having a larger opening required for controlling the temperature of the fuel cell 1 is selectively output, and the minimum required opening of the three-way valve 17 is increased in accordance with the input purge time. I have. Therefore, if the purge time is prolonged without the cell voltage of the fuel cell 1 recovering, the combustion state of the purged hydrogen in the combustor 5 may continue for a long time, and the temperature of the coolant may rise excessively. However, in the present embodiment, the three-way valve 17 moves in the direction to open the heat exchanger passage 20 side according to the purge time and the flow rate of the coolant to the heat exchanger 6 increases. Can be suppressed, and its deterioration can be prevented.

  In the present embodiment, in addition to the effect (A) in the second embodiment, the following effects can be obtained.

  (H) The three-way valve minimum required opening calculating means 39 increases the minimum required opening of the three-way valve 17 in accordance with the purge time by the purge means, so that the cell voltage of the fuel cell 1 is not recovered and the purge time is long. If this happens, the combustion state of the purged hydrogen in the combustor 5 may continue for a long time, and the temperature of the coolant may rise excessively. However, in the present embodiment, the three-way valve depends on the purge time. Since 17 moves in a direction to open the heat exchanger passage 20 side, the flow rate of the coolant to the heat exchanger 6 increases, so that an excessive rise in the temperature of the coolant can be suppressed and its deterioration can be prevented.

(Tenth embodiment)
FIGS. 30 to 33 show the first and second examples of the ninth embodiment of the fuel cell system to which the present invention is applied, and FIG. 30 shows the heat medium supply system and control unit of the first example of the eighth embodiment. FIG. 31 is a control block diagram of a three-way valve minimum required opening calculating means of the first embodiment, and FIG. 32 is a heat medium supply system of a second embodiment of the eighth embodiment. And FIG. 33 is a control block diagram of a three-way valve minimum required opening calculating means of the second embodiment. In the present embodiment, the minimum required opening of the three-way valve is adjusted in accordance with the temperature of the coolant or the temperature of the combustion gas passing through the heat exchanger. 20 to 29 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In the fuel cell system of the first embodiment, as shown in FIG. 30, a temperature detecting means 41 for detecting the temperature of the coolant at the outlet of the heat exchanger 6 in the heat exchanger passage 20 is provided. The input is input to the three-way valve minimum required opening calculating means 40 of the controller 9.

  As shown in FIG. 31, the three-way valve minimum required opening calculating means 40 is input with a three-way valve minimum required opening calculating unit 40A (same configuration as shown in FIG. 25 of the seventh embodiment). A coefficient generator 40B that outputs a coefficient that increases in accordance with the temperature of the coolant at the outlet of the heat exchanger 6 by the temperature detector 41, and a three-way valve minimum required opening that is output by the three-way valve minimum required opening calculator 40A A multiplier 40C for multiplying the signal by the coefficient output from the coefficient generation unit 40B.

  The coefficient generator 40B outputs a coefficient “1” when the input temperature from the temperature detector 41 does not reach the preset temperature, and outputs the coefficient “1” when the input temperature from the temperature detector 41 is lower than the preset temperature. If the temperature exceeds the coefficient, the coefficient is increased so as to increase as the temperature rises, and outputs a coefficient of “1” or more.

  Therefore, the three-way valve minimum necessary opening degree calculating means 40 outputs the coefficient "1" when the input temperature from the temperature detecting means 41 does not reach the preset set temperature. The three-way valve minimum necessary opening signal output by the minimum valve necessary opening calculating section 40A is multiplied by the coefficient "1" by the multiplier 40C and output as it is. Further, when the temperature detected by the temperature detecting means 41 exceeds a preset temperature, a coefficient of “1” or more which increases in accordance with the temperature rise is output, so that the three-way valve minimum required opening degree is output. The multiplier 40C multiplies the three-way valve minimum required opening signal output by the arithmetic unit 40A by a coefficient of "1" or more, and outputs the increased minimum required opening.

  The output of the three-way valve minimum necessary opening calculating means 40 is input to the three-way valve opening setting means 34, and is compared with the three-way valve opening for controlling the coolant temperature from the three-way valve temperature adjusting opening calculating means 46. The larger opening is selected as the target opening (select high), and the opening of the three-way valve 17 is driven to be the target opening.

  FIG. 32 and FIG. 33 are system configuration diagrams of a fuel cell system including a heat medium supply system and a control unit showing a second example of the fuel cell system of the tenth embodiment, and a three-way valve minimum required opening degree calculating means. It is a control block diagram. In the fuel cell system shown in the present (second) embodiment, the minimum required opening of the three-way valve calculated by the three-way valve minimum required opening calculating means is based on the coolant temperature at the heat exchanger outlet in the first embodiment. Instead of the calculation, the calculation is performed based on the temperature of the combustor exhaust gas at the outlet of the heat exchanger. 20 to 31 are denoted by the same reference numerals, and description thereof will be omitted or simplified.

  In the fuel cell system of the second embodiment, as shown in FIG. 32, a temperature detecting means 43 for detecting the temperature of the combustion exhaust gas at the outlet of the heat exchanger 6 in the heat exchanger passage 20 is provided. Is input to the three-way valve minimum required opening calculating means 42 of the controller 9.

  As shown in FIG. 33, the three-way valve minimum required opening calculating means 42 is input with a three-way valve minimum required opening calculating unit 42A (same configuration as shown in FIG. 25 of the seventh embodiment). A coefficient generator 42B for outputting a coefficient that increases in accordance with the temperature of the combustion exhaust gas at the outlet of the heat exchanger 6 by the temperature detector 43, and a three-way valve minimum required opening output from the three-way valve minimum required opening calculator 42A. And a multiplier 42C for multiplying the degree signal by the coefficient output from the coefficient generation unit 42B.

  The coefficient generator 42B outputs a coefficient “1” when the input temperature from the temperature detector 43 does not reach a preset reference temperature, and the input temperature from the temperature detector 43 is set in advance. When the temperature exceeds the reference temperature, a coefficient of “1” or more that increases as the temperature rises is output.

  Therefore, the three-way valve minimum required opening degree calculating means 42 outputs the coefficient “1” from the coefficient generator 42B when the input temperature from the temperature detecting means 43 does not reach the preset reference value temperature. The three-way valve minimum necessary opening signal output by the three-way valve minimum necessary opening calculating section 42A is multiplied by a coefficient "1" by the multiplier 42C and output as it is. If the input temperature detected by the temperature detecting means 43 exceeds a preset reference temperature, a coefficient of “1” or more that increases in accordance with the temperature rise is output. The multiplier 42C multiplies the minimum required opening signal output from the opening calculator 42A by a coefficient of "1" or more, and outputs the increased minimum required opening.

  The output of the three-way valve minimum required opening calculating means 42 is input to the three-way valve opening setting means 34 and compared with the three-way valve opening for controlling the coolant temperature from the three-way valve temperature adjusting opening calculating means 46. The larger opening is selected as the target opening (select high), and the opening of the three-way valve 17 is driven to be the target opening.

  As described above, in the present embodiment, when the coolant temperature at the outlet of the heat exchanger 6 or the combustion exhaust gas temperature does not reach a preset value, the three-way valve minimum required opening degree and the fuel cell 1 If the temperature of the coolant at the outlet of the heat exchanger 6 or the temperature of the combustion exhaust gas exceeds a preset value, the temperature rises. , The minimum required opening of the three-way valve 17 is increased. Therefore, even when the coolant temperature at the outlet of the heat exchanger 6 excessively rises due to insufficient coolant flow rate to the heat exchanger 6 or variation in combustion in the combustor 5, the three-way valve 17 is operated in accordance with the coolant temperature. Since the coolant moves toward the heat exchanger passage 20 and the flow rate of the coolant in the heat exchanger 6 increases, an excessive rise in the temperature of the coolant can be suppressed and its deterioration can be prevented.

  In the present embodiment, in addition to the effect (A) in the second embodiment, the following effects can be obtained.

  (T) temperature detecting means 41, 43 for detecting the temperature of the heat medium or the combustion exhaust gas which has passed through the heat exchanging means 6; As the temperature of the heat medium at the outlet 6 increases, the minimum required opening degree of the three-way valve to the heat exchange means 6 increases. Even when the coolant temperature at the outlet 6 rises excessively, the three-way valve 17 moves toward the heat exchanger passage 20 according to the coolant temperature and the coolant flow rate in the heat exchanger 6 increases. Excessive temperature rise can be suppressed and its deterioration can be prevented.

FIG. 1 is a system configuration diagram of a fuel cell system according to an embodiment of the present invention. FIG. 3 is a control block diagram of the control unit. 6 is a control flowchart of a heating operation execution determining unit. Similarly, a heating operation means "control flowchart. FIG. 6 is a system configuration diagram of a fuel cell system according to a second embodiment of the present invention. FIG. 3 is a control block diagram of the control unit. 7 is a control flowchart of a hydrogen purge determination unit. 7 is a control flowchart of the hydrogen purging unit. FIG. 9 is a system configuration diagram of a fuel cell system according to a third embodiment of the present invention. FIG. 3 is a control block diagram of the control unit. 7 is a control flowchart of a heat medium passage selecting unit. 7 is a control flowchart of the hydrogen purging unit. FIG. 14 is a control block diagram of a control unit of a fuel cell system according to a fourth embodiment of the present invention. 7 is a control flowchart of the hydrogen purging unit. FIG. 13 is a system configuration diagram of a fuel cell system according to a fifth embodiment of the present invention. 7 is a control flowchart of a heat medium passage selecting unit. 13 is a control flowchart of a hydrogen purge determination unit of a fuel cell system according to a sixth embodiment of the present invention. 7 is a control flowchart of a heat medium passage selecting unit. 7 is a control flowchart of the hydrogen purging unit. FIG. 16 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit according to a first example of the seventh embodiment of the present invention. FIG. 4 is a control block diagram of pump control executed by the control unit of the first embodiment. FIG. 4 is a control block diagram of three-way valve control executed by the control unit of the first embodiment. FIG. 4 is a characteristic diagram showing an operation state of a heat medium supply system under pump control and three-way valve control according to the first embodiment. FIG. 18 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit according to a second example of the seventh embodiment of the present invention. FIG. 9 is a control block diagram of a three-way valve minimum required opening calculating means of the second embodiment. FIG. 18 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit according to an eighth embodiment of the present invention. FIG. 28 is a control block diagram of a three-way valve control unit executed by the control unit of the eighth embodiment. FIG. 19 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit according to a ninth embodiment of the present invention. FIG. 21 is a control block diagram of a three-way valve control unit executed by the control unit of the ninth embodiment. FIG. 19 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit according to a first example of the tenth embodiment of the present invention. FIG. 3 is a control block diagram of a three-way valve minimum required opening calculating means of the first embodiment. FIG. 21 is a system configuration diagram of a fuel cell system including a heat medium supply system and a control unit according to a second example of the tenth embodiment of the present invention. FIG. 9 is a control block diagram of a three-way valve minimum required opening calculating means of the second embodiment.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 Fuel cell 2 Hydrogen supply system as hydrogen supply means 3 Oxidation gas supply system 4 Heat medium supply system 5 Combustor as combustion gas generation means 6 Heat exchanger as heat exchange means 7, 33 Temperature sensor 8 Wattmeter 9 Control Unit 11 Circulation path 13 Purge valve 16 as a purging means 16 Pump 17 Three-way valve 18 Radiator 19 Radiator fan 20 Heat exchange passage 21 Exhaust three-way valve 25 Heating operation execution judging means 26 Heating operation means 28 Hydrogen purge judging means 29, 31, 32 Hydrogen purging means 30 Heat medium flow path selecting means 33, 36, 39, 40 Three-way valve minimum required opening calculating means 34, 37 Three-way valve opening setting means 35, 41, 43 Temperature detecting means 44 Coolant target flow rate setting means 45 Pump control means 46 Three-way valve temperature control opening calculation means

Claims (22)

A fuel cell that generates electricity by reacting hydrogen and oxygen;
Heat medium supply means for circulating and supplying a heat medium to the fuel cell,
Combustion gas generating means for reacting hydrogen and oxygen to generate high-temperature combustion gas,
Heat exchange means for warming up the fuel cell system by applying the heat of the combustion gas to the heat medium and heating it during cold start;
Hydrogen purging means for discharging gas in a hydrogen supply means for supplying hydrogen to the fuel cell through the combustion gas generating means,
Control means for controlling the temperature of the fuel cell system by controlling the fuel cell and the hydrogen purging means and adjusting the temperature of the heating medium.
A fuel is provided, wherein a heat exchange means bypass means for discharging the combustion gas without passing through the heat exchange means is provided, and the combustion gas is discharged by bypassing the heat exchange means when executing hydrogen purging by the control means. Battery system. A fuel cell that generates electricity by reacting hydrogen and oxygen;
Heat medium supply means for circulating and supplying a heat medium to the fuel cell,
Combustion gas generating means for reacting hydrogen and oxygen to generate high-temperature combustion gas,
Heat exchange means for warming up the fuel cell system by applying heat of the combustion gas to the heat medium and heating it during cold start,
A heat exchange means bypass passage for bypassing the heat exchange means and flowing the heat medium,
Heat medium passage switching means for switching the passage of the heat medium to the heat exchange means side or the heat exchange means bypass passage side;
Hydrogen purging means for discharging gas in the hydrogen supply means for supplying hydrogen to the fuel cell through the combustion gas generating means,
Control means for controlling the temperature of the fuel cell system by controlling the temperature of the heat medium by controlling the fuel cell, the heat medium passage switching means and the hydrogen purge means,
The fuel cell system according to claim 1, wherein the control unit allows the heat medium to flow to the heat exchange unit by a predetermined amount even when the heat medium passage is on the heat exchange unit bypass passage side. A fuel cell that generates electricity by reacting hydrogen and oxygen;
Heat medium supply means for circulating and supplying a heat medium to the fuel cell,
Combustion gas generating means for reacting hydrogen and oxygen to generate high-temperature combustion gas,
Heat exchange means for warming up the fuel cell system by applying heat of the combustion gas to the heat medium and heating it during cold start,
A heat exchange means bypass passage for bypassing the heat exchange means and flowing the heat medium,
Heat medium passage switching means for switching the passage of the heat medium to the heat exchange means side or the heat exchange means bypass passage side;
Hydrogen purging means for discharging gas in the hydrogen supply means for supplying hydrogen to the fuel cell through the combustion gas generating means,
A control means for controlling the temperature of the fuel cell system by controlling the temperature of the heat medium by controlling the fuel cell, the heat medium passage switching means and the hydrogen purging means,
When the heat medium is flowing through the heat exchange means bypass passage when the hydrogen purge is requested, the control means switches the heat medium passage to the heat exchange means and then performs the hydrogen purge. Fuel cell system.   If the heat medium flows through the heat exchange unit bypass passage when the hydrogen purge is requested, the control unit inhibits the purge until the heat medium flows through the heat exchange unit. The fuel cell system according to claim 3. The fuel cell system includes a heat medium cooling unit that cools the heat medium in the heat exchange unit bypass passage and a heat medium quenching unit that rapidly cools the temperature of the heat medium faster than usual.
When the heat medium is flowing through the heat exchange means bypass passage when the hydrogen purge is requested, the control means quenches the heat medium to a predetermined temperature or less by the heat medium quenching means, and then passes the heat medium passage. The fuel cell system according to claim 4, wherein the hydrogen purging is performed after switching to the heat exchange means side.   If the heat medium is flowing through the heat exchange means bypass passage when the hydrogen purge is requested, the control means switches the heat medium passage to the heat exchange means and then performs the hydrogen purge or inhibits the purging. 5. The fuel cell system according to claim 4, wherein the selection is made according to the urgency of the purge.   7. The fuel cell system according to claim 6, wherein when the urgency of the requested hydrogen purge is high, the control unit switches the heat medium passage to the heat exchange unit to perform the hydrogen purge.   8. The fuel according to claim 7, wherein, when the urgency of the hydrogen purge decreases during execution of the hydrogen purge, the control unit switches the heat medium passage to the heat exchange unit bypass passage and inhibits the hydrogen purge. Battery system.   7. The fuel cell system according to claim 6, wherein the control unit prohibits the purging when the requested urgency of the hydrogen purging is low. The fuel cell system includes a heat medium cooling unit that cools the heat medium in the heat exchange unit bypass passage and a heat medium quenching unit that rapidly cools the temperature of the heat medium,
When the urgency of the requested hydrogen purge is low, the control means temporarily inhibits the hydrogen purge and, after the heat medium is rapidly cooled to a predetermined temperature or less by the heat medium quenching means, moves the heat medium passage to the heat exchange means side. 7. The fuel cell system according to claim 6, wherein hydrogen purging is permitted after switching.   11. The fuel cell system according to claim 6, wherein the control unit determines the urgency of the purge from the cell voltage of the fuel cell.   The fuel cell system according to any one of claims 6 to 10, wherein the control unit determines the urgency of the purge from the operation time of the fuel cell.   The fuel cell system according to any one of claims 6 to 10, wherein the control unit determines the urgency of the purge from an operation load of the fuel cell.   The fuel cell system according to any one of claims 6 to 10, wherein the control means determines the urgency of the purge from a purge duration of the fuel cell.   The fuel cell system according to claim 5, wherein the heat medium quenching means increases a flow rate of the heat medium passing through the heat exchange means bypass passage and the heat medium cooling means. The fuel cell system includes a radiator in a heat exchange unit bypass passage,
11. The fuel cell system according to claim 5, wherein the heat medium quenching means increases an amount of air passing through the radiator. The heat medium supply unit includes a pump that circulates a coolant of the fuel cell,
The heat medium passage switching means is configured by a three-way valve capable of adjusting the flow division of a heat medium through a heat exchange means and a heat exchange means bypass passage,
The control means includes a three-way valve temperature control opening calculating means for calculating a three-way valve opening to the heat exchange means passage passage side necessary for controlling the temperature of the fuel cell, and a minimum heat medium required for the heat exchange means. A three-way valve minimum necessary opening calculating means for calculating a minimum required opening of the three-way valve in accordance with the pump discharge medium flow rate in order to secure a flow rate; and a three-way valve opening calculated by the three-way valve temperature regulating opening calculating means. If the degree is less than the minimum required opening calculated by the three-way valve minimum required opening calculating means, three-way valve opening setting means for setting the three-way valve opening to the minimum required opening is provided. The fuel cell system according to claim 2, wherein:   18. The fuel cell system according to claim 17, wherein the three-way valve minimum required opening calculating means calculates the minimum required opening of the three-way valve based on the pump speed or the pump drive duty ratio.   The three-way valve opening setting unit sets the three-way valve opening to the minimum required opening at the time of or immediately before purging by the purging unit when the three-way valve opening is less than the minimum required opening. The fuel cell system according to claim 17 or 18, wherein   The fuel according to any one of claims 17 to 19, wherein the three-way valve minimum required opening calculating means increases the minimum required opening of the three-way valve according to a purge time by a purge means. Battery system. The fuel cell system includes a temperature detection unit that detects a temperature of the heat medium that has passed through the heat exchange unit,
18. The method according to claim 17, wherein the three-way valve minimum required opening calculating means increases the minimum required opening of the three-way valve to the heat exchanging means as the detected heat medium temperature at the heat exchanging means outlet increases. The fuel cell system according to claim 19. The fuel cell system includes a temperature detection unit that detects a temperature of the combustion exhaust gas that has passed through the heat exchange unit,
The three-way valve minimum required opening calculating means increases the minimum required opening of the three-way valve to the heat exchange means as the detected temperature of the combustion exhaust gas at the outlet of the heat exchange means increases. The fuel cell system according to any one of claims 17 to 19.

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