Abstract:
The present invention reliably extinguishes fires in devices that have exceeded the guaranteed temperature without the use of a sensor. An in-vehicle fire extinguisher ( 100 ) extinguishes fires using an air conditioner for heating or cooling the interior of a vehicle compartment. A coolant discharged from a compressor ( 101 ) is pumped into the compressor ( 101 ) through a circulation path ( 106 ) via a condenser ( 102 ), an expansion valve ( 103 ) and an evaporator ( 105 ). A fire extinguishing unit ( 104 ) is provided to the circulation path ( 106 ) between the expansion valve ( 103 ) and the compressor ( 101 ). When a device mounted in a vehicle exceeds the guaranteed temperature, the fire extinguishing unit ( 104 ) melts so that coolant pumped from the circulation path ( 106 ) is discharged to the exterior and extinguishes the device fire.

Description:
TECHNICAL FIELD 
       [0001]    The present invention relates to an in-vehicle fire extinguishing apparatus that performs fire extinguishing by utilizing an air conditioning apparatus that heats or cools the vehicle interior. 
       BACKGROUND ART 
       [0002]    Conventionally, a fire extinguishing device disclosed in PTL 1 has been known in which, when an abnormality detection sensor detects an abnormality of a storage battery such as an abrupt change in temperature, a flame-retardant refrigerant circulating in a refrigeration circuit in a cooling device is discharged into a battery pack through a discharge pipe. According to PTL 1, by using refrigerant as a fire extinguishing agent, fire extinguishing can be promptly performed even when fire occurs in the storage battery. 
       CITATION LIST 
     Patent Literature 
     PTL 1 
     Japanese Patent Application Laid-Open No. 2010-110356 
     SUMMARY OF INVENTION 
     Technical Problem 
       [0003]    However, in PTL 1, since fire extinguishing is performed when the abnormality detection sensor detects an abnormality, fire extinguishing cannot be performed in the case where the abnormality detection sensor is broken or damaged by impact or the like applied to the vehicle from the outside. 
         [0004]    An object of the present invention is to provide an in-vehicle fire extinguishing apparatus that can surely perform fire extinguishing and the like, by performing the fire extinguishing without using a sensor. 
       Solution to Problem 
       [0005]    An in-vehicle fire extinguishing apparatus of an embodiment of the present invention is configured to perform fire extinguishing by utilizing an air conditioning apparatus that heats or cools a vehicle interior, the in-vehicle fire extinguishing apparatus including: an incombustible or flame-retardant refrigerant; a compressor that compresses the refrigerant in such a manner as to increase a temperature and a pressure of the refrigerant; a condenser that causes a high-temperature and high-pressure refrigerant compressed by the compressor to release heat; an expansion valve that expands the refrigerant that is caused to release heat by the condenser in such a manner as to reduce the temperature and the pressure of the refrigerant; an evaporator that causes a low-temperature and low-pressure refrigerant expanded by the expansion valve to absorb heat; a circulation path that causes the refrigerant output from the compressor to enter the compressor through the condenser, the expansion valve, and the evaporator; and a fire extinguishing section provided in the circulation path between the expansion valve and the compressor, the fire extinguishing section allowing the refrigerant entered from the circulation path to be output to the circulation path under an environment of a temperature below a predetermined temperature equal to or greater than a guaranteed temperature of a device mounted in a vehicle, and emitting the refrigerant entered from the circulation path to an exterior so as to perform fire extinguishing by being melted under an environment of a temperature equal to or greater than the predetermined temperature. 
       Advantageous Effects of Invention 
       [0006]    According to the present invention, fire extinguishing and the like can be surely performed, by performing the fire extinguishing without using a sensor. 
     
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         [0007]      FIG. 1  is a block diagram illustrating a configuration of an in-vehicle fire extinguishing apparatus according to Embodiment 1 of the present invention; 
           [0008]      FIG. 2  is a perspective view of a fire extinguishing section in Embodiment 1 of the present invention; 
           [0009]      FIG. 3  is a sectional view taken along line A-A of  FIG. 2  illustrating a state where a closure section in Embodiment 1 of the present invention is not yet melted; 
           [0010]      FIG. 4  is a sectional view taken along line A-A of  FIG. 2  illustrating a state where the closure section in Embodiment 1 of the present invention has been melted; 
           [0011]      FIG. 5  is a perspective view of a charger on which the fire extinguishing section in Embodiment 1 of the present invention is attached; 
           [0012]      FIG. 6  is an enlarged sectional view of a main part of a fire extinguishing section in Embodiment 2 of the present invention; 
           [0013]      FIG. 7  is an enlarged sectional view of a main part of a fire extinguishing section in Embodiment 3 of the present invention; 
           [0014]      FIG. 8  is an enlarged sectional view of a main part of a fire extinguishing section in Embodiment 4 of the present invention; and 
           [0015]      FIG. 9  is an enlarged sectional view of a main part of a fire extinguishing section in Embodiment 5 of the present invention. 
       
    
    
     DESCRIPTION OF EMBODIMENTS 
       [0016]    In the following, embodiments of the present invention will be described in detail with reference to the accompanying drawings. 
       Embodiment 1 
     Configuration of In-Vehicle Fire Extinguishing Apparatus 
       [0017]    A configuration of in-vehicle fire extinguishing apparatus  100  according to Embodiment 1 of the present invention is described with reference to  FIG. 1 .  FIG. 1  is a block diagram illustrating a configuration of in-vehicle fire extinguishing apparatus  100  according to an embodiment of the present embodiment. 
         [0018]    In-vehicle fire extinguishing apparatus  100  includes compressor  101 , condenser  102 , expansion valve  103 , fire extinguishing section  104 , evaporator  105 , and circulation path  106 . 
         [0019]    Air conditioning section  150  includes compressor  101 , condenser  102 , expansion valve  103 , evaporator  105 , and circulation path  106 . Air conditioning section  150  serves as an air conditioning apparatus, and heats or cools the vehicle interior. 
         [0020]    Compressor  101  compresses refrigerant having entered from evaporator  105  through circulation path  106  so as to increase the temperature and pressure of the refrigerant. Compressor  101  supplies the high-temperature and high-pressure refrigerant to condenser  102  through circulation path  106 . Here, the refrigerant is incombustible or flame-retardant, and, for example, carbon dioxide, HFC-134a or HF0-1234yf is used as the refrigerant. An incombustible refrigerant is difficult to ignite, and does not continuously burn. A flame-retardant refrigerant is difficult to ignite, and even when it is ignited and combustion is continued, the speed is extremely low. In the present invention, an incombustible refrigerant is preferably used. 
         [0021]    Condenser  102  causes the high-temperature and high-pressure refrigerant having entered from compressor  101  through circulation path  106  to release heat so as to liquefy the refrigerant, and supplies the liquefied refrigerant to expansion valve  103  through circulation path  106 . The heat released from the refrigerant in condenser  102  heats up the vehicle interior. 
         [0022]    Expansion valve  103  expands the refrigerant having entered from condenser  102  through circulation path  106  so as to reduce the temperature and pressure of the refrigerant. Expansion valve  103  supplies the low-temperature and low-pressure refrigerant to fire extinguishing section  104  through circulation path  106 . 
         [0023]    Under an environment of a predetermined temperature below a guaranteed temperature of a device mounted on the vehicle (hereinafter referred to as “fire extinguishing start temperature”), fire extinguishing section  104  supplies the low-temperature and low-pressure refrigerant having entered from expansion valve  103  through circulation path  106  to evaporator  105  through circulation path  106 . Under an environment of the fire extinguishing start temperature or above, a part of fire extinguishing section  104  is melted, and the low-temperature and low-pressure refrigerant having entered from expansion valve  103  through circulation path  106  is emitted out of in-vehicle fire extinguishing apparatus  100 , whereby fire extinguishing is performed. Here, the refrigerant having entered fire extinguishing section  104  from expansion valve  103  through circulation path  106  has a pressure higher than that of the outside air. It is to be noted that details of the configuration of fire extinguishing section  104  will be described later. 
         [0024]    Here, examples of the device mounted in the vehicle include a motor, a charger, a battery, and an ECU. A guaranteed temperature of a device includes an operation guarantee temperature and a storage guarantee temperature. The operation guarantee temperature of a device is a temperature at which the device can normally function. When the device is used at a temperature greater than the operation guarantee temperature, the device does not normally operate, or the lifetime of the device is shortened from the guarantee lifetime. The operation guarantee temperature of a device mounted in an electric automobile provided with no engine is, for example, 125° C. In the case where the operation guarantee temperature of a device mounted in an electric automobile provided with no engine is 125° C., the fire extinguishing start temperature is set to, for example, 150° C. In addition, the storage guarantee temperature of a device is a temperature at which the possibility that the device is broken is high. The storage guarantee temperature of a device mounted in an electric automobile provided with no engine is, for example, 150° C. In the case where the storage guarantee temperature of a device mounted in an electric automobile provided with no engine is 150° C., the fire extinguishing start temperature is set to a temperature greater than 150° C. It is to be noted that the fire extinguishing start temperature may be the same as the operation guarantee temperature or the storage guarantee temperature of the device mounted in the vehicle. 
         [0025]    Evaporator  105  evaporates the refrigerant having entered from fire extinguishing section  104  through circulation path  106  such that the refrigerant absorbs heat, and then evaporator  105  supplies the refrigerant having absorbed the heat to compressor  101  through circulation path  106 . When heat is absorbed by the refrigerant in evaporator  105 , the vehicle interior is cooled. 
         [0026]    Circulation path  106  circulates the refrigerant output from compressor  101  through condenser  102 , expansion valve  103 , fire extinguishing section  104 , evaporator  105  and compressor  101 , in the named order. 
       &lt;Configuration of Fire Extinguishing Section&gt; 
       [0027]    The configuration of fire extinguishing section  104  in Embodiment 1 of the present invention is described with reference to  FIG. 2  and  FIG. 3 .  FIG. 2  is a perspective view of fire extinguishing section  104  in the present embodiment.  FIG. 3  is a sectional view taken along line A-A of  FIG. 2  illustrating a state where closure section  203  is not yet melted. 
         [0028]    Fire extinguishing section  104  includes fire extinguishing board  201 , void  202  (see  FIG. 3 ), and closure section  203 . 
         [0029]    Fire extinguishing board  201  has a plate-shape. Fire extinguishing board  201  is provided with closure section  203 . 
         [0030]    Void  202  is surrounded by wall section  201   a . Refrigerant enters void  202  from circulation path  106 , and the refrigerant having entered void  202  is output to circulation path  106 . 
         [0031]    Closure section  203  is formed of a material different from that of fire extinguishing board  201 . Closure section  203  is formed of a material that is melted by a temperature greater than the fire extinguishing start temperature, and closure section  203  is attached to fire extinguishing board  201 . For example, closure section  203  is formed of a fusible alloy which is used for thermal fuses, and closure section  203  is attached to fire extinguishing board  201 . In addition, closure section  203  may be formed of tin or a solder and attached to fire extinguishing board  201  such that closure section  203  is melted at the fusing point of tin or solder. When closure section  203  is formed of a solder, closure section  203  can be melted at, for example, 183° C. 
         [0032]    Closure section  203  is provided in wall section  201   a  that separates void  202  from the exterior in fire extinguishing section  104 . For example, closure section  203  is attached to wall section  201   a  by welding. As viewed in the thickness cross-section of wall section  201   a , closure section  203  is formed in a rectangular shape (see  FIG. 3 ). When provided in wall section  201   a , closure section  203  seals void  202  from the exterior. 
         [0033]    Under an environment of a temperature below the fire extinguishing start temperature, the state where closure section  203  is provided in fire extinguishing board  201  is maintained. Thus, the refrigerant having entered void  202  from circulation path  106  is output to circulation path  106  without being emitted to the exterior of fire extinguishing section  104 . In addition, under an environment of the fire extinguishing start temperature or above, closure section  203  is melted by heat. Thus, the refrigerant having entered void  202  from circulation path  106  is emitted out of fire extinguishing section  104 . Here, at the time of extinguishing fire, the entirety of closure section  203  is not have to be melted as long as the refrigerant having entered void  202  is emitted out of fire extinguishing section  104 . In view of this, the melting of closure section  203  includes the case where the entirety of closure section  203  is melted and the case where a part of closure section  203  is melted. 
         [0034]    A predetermined pressure is exerted on closure section  203  by the refrigerant having entered void  202 , and therefore, closure section  203  is so provided in fire extinguishing board  201  as not to be dropped off from fire extinguishing board  201  by the pressure of the refrigerant under an environment of a temperature below the fire extinguishing start temperature. 
       &lt;Fire Extinguishing Method&gt; 
       [0035]    A fire extinguishing method in Embodiment 1 of the present invention is described with reference to  FIG. 3  and  FIG. 4 .  FIG. 4  is a sectional view taken along line A-A of  FIG. 2  illustrating a state where closure section  203  has been melted. 
         [0036]    Referring to  FIG. 3 , closure section  203  is heated and melted by fire when fire occurs at device  301 , under an environment of the fire extinguishing start temperature or above. When part of closure section  203  is melted, or when closure section  203  is melted and dropped off from fire extinguishing board  201  as illustrated in  FIG. 4 , through hole  401  that connects void  202  and the exterior is defined in fire extinguishing board  201 . In this state, the refrigerant having entered void  202  is emitted to device  301  and the area around device  301  from through hole  401 , so as to extinguish the fire. 
         [0037]    At this time, before closure section  203  is melted, wall section  201   a  and closure section  203  are under a predetermined pressure exerted by the refrigerant having entered void  202 . Accordingly, the refrigerant which is emitted from through hole  401  when closure section  203  is melted has a certain force caused by the release of the pressure. 
       &lt;Exemplary Use of Fire Extinguishing Section&gt; 
       [0038]    An exemplary use of fire extinguishing section  104  in Embodiment 1 of the present invention is described with reference to  FIG. 5 .  FIG. 5  is a perspective view of charger  502  on which fire extinguishing section  104  in the present embodiment is attached. 
         [0039]    As illustrated in  FIG. 5 , fire extinguishing section  104  is attached to charger  502  through cover  501 . 
         [0040]    Cover  501  covers the space between fire extinguishing section  104  and charger  502 . 
         [0041]    Between cover  501  and charger  502 , power source circuit section  504  on which device  503  is mounted is housed. On the upper side of cover  501 , fire extinguishing section  104  is attached. 
         [0042]    In  FIG. 5 , fire extinguishing board  201  includes pressure-regulating valve  505 . Pressure-regulating valve  505  adjusts the pressure of the refrigerant having entered void  202  exerted on fire extinguishing board  201 . 
         [0043]    In the above-mentioned configuration, when fire is caused by ignited device  503 , closure section  203  is melted. Thus, the refrigerant having entered fire extinguishing board  201  from circulation path  106  is scattered to power source circuit section  504  so as to extinguish fire. 
       &lt;Effect of the Present Embodiment&gt; 
       [0044]    According to the present embodiment, fire or the like can be surely extinguished by performing fire extinguishing without using a sensor. 
         [0045]    In addition, according to the present embodiment, the closure section has a simple rectangular shape in the thickness cross-section of the wall section forming the fire extinguishing section. Thus, the closure section can be readily formed, and the calculation of the pressure of the refrigerant exerted on the closure section can be easily performed, and in addition, the temperature at which the closure section is melted can be readily set since the calculation of the heat conduction characteristics in the closure section is readily performed. 
         [0046]    In addition, according to the present embodiment, when a pressure-regulating valve is provided in the fire extinguishing section, it is possible to prevent the closure section from being dropped off from the fire extinguishing board by the pressure of the refrigerant exerted on the closure section, under an environment of a temperature below the fire extinguishing start temperature. 
       &lt;Modification of the Present Embodiment&gt; 
       [0047]    While the closure section has a rectangular shape in the thickness cross-section of the wall section of the fire extinguishing board in the present embodiment, the present invention is not limited to this, and the closure section may have a square shape in the thickness cross-section of the wall section of the fire extinguishing board. 
       Embodiment 2 
     Configuration of Fire Extinguishing Section 
       [0048]    The configuration of fire extinguishing section  600  in Embodiment 2 of the present invention is described with reference to  FIG. 6 .  FIG. 6  is an enlarged sectional view of a main part of fire extinguishing section  600  in the present embodiment. 
         [0049]    As compared with fire extinguishing section  104  according to Embodiment 1 illustrated in  FIG. 2  and  FIG. 3 , fire extinguishing section  600  illustrated in  FIG. 6  includes closure section  601  in place of closure section  203 . It is to be noted that, in  FIG. 6 , the same reference numerals are attached to the components same as those in  FIG. 2  to  FIG. 4 , and the descriptions thereof are omitted. In addition, the in-vehicle fire extinguishing apparatus according to the embodiment of the present embodiment has the same configuration as that illustrated in  FIG. 1 , and the description thereof is omitted. 
         [0050]    Fire extinguishing section  600  includes fire extinguishing board  201 , void  202 , and closure section  601 . 
         [0051]    Fire extinguishing board  201  is provided with closure section  601 . 
         [0052]    Closure section  601  is formed of a material different from that of fire extinguishing board  201 . Closure section  601  is formed of a material that melts under an environment of the fire extinguishing start temperature or above, and is attached to fire extinguishing board  201 . The material of closure section  601  is same as that of closure section  203  of Embodiment 1, and the description thereof is omitted. 
         [0053]    Closure section  601  is provided in wall section  201   a  that separates void  202  from the exterior in fire extinguishing section  600 . Closure section  601  has irregularity on side wall  601   a , and is engaged with wall section  201   a  by the irregularity. When provided in wall section  201   a , closure section  601  seals void  202  from the exterior. 
         [0054]    Under an environment of a temperature below the fire extinguishing start temperature, the state where closure section  601  is provided in fire extinguishing board  201  is maintained. Thus, the refrigerant having entered void  202  from circulation path  106  is output to circulation path  106  without being emitted to the exterior of fire extinguishing section  600 . In addition, under an environment of the fire extinguishing start temperature or above, closure section  601  is melted by heat. Thus, the refrigerant having entered void  202  from circulation path  106  is emitted out of fire extinguishing section  600 . 
         [0055]    A predetermined pressure is exerted on closure section  601  by the refrigerant having entered void  202 , and therefore, closure section  601  is so provided in fire extinguishing board  201  as not to be dropped off from fire extinguishing board  201  by the pressure of the refrigerant under an environment of a temperature below the fire extinguishing start temperature. 
       &lt;Fire Extinguishing Method&gt; 
       [0056]    A fire extinguishing method in Embodiment 2 of the present invention is described with reference to  FIG. 6 . 
         [0057]    Referring to  FIG. 6 , closure section  601  is heated and melted by fire when fire occurs at device  301 , under an environment of the fire extinguishing start temperature or above. At this time, the protruding parts of the irregularity of side wall  601   a  of closure section  601  are melted, and closure section  601  drops off from fire extinguishing board  201 , or a gap is defined between side wall  601   a  and wall section  201   a . Accordingly, through the through hole defined after closure section  601  drops off, or through the through hole in the form of the gap defined between side wall  601   a  and wall section  201   a , the refrigerant can be emitted out of void  202 . 
         [0058]    It is to be noted that the other points of the fire extinguishing method in the present embodiment are same as in Embodiment 1, and the description thereof is omitted. 
       &lt;Effect of the Present Embodiment&gt; 
       [0059]    According to the present invention, fire or the like can be surely extinguished by performing fire extinguishing without using a sensor to detect temperature changes. 
         [0060]    In addition, according to the present embodiment, since the closure section is engaged by the irregularity with the wall section of the fire extinguishing board, it is possible to securely prevent the closure section from dropping off due to the shock and the pressure of the refrigerant applied to the in-vehicle fire extinguishing apparatus. 
         [0061]    In addition, according to the present embodiment, the closure section and the fire extinguishing board are engaged with each other by the irregularity, and, under an environment of the fire extinguishing start temperature or above, the refrigerant can be emitted to the exterior by only melting the protruding part of the side wall of the closure section. Thus, the closure section can be melted with low energy, and fire can be extinguished at an early stage. 
         [0062]    In addition, according to the present embodiment, when a pressure-regulating valve is provided in the fire extinguishing section, it is possible to prevent the closure section from being dropped off from the fire extinguishing board by the pressure of the refrigerant exerted on the closure section, under an environment of a temperature below the fire extinguishing start temperature. 
       Embodiment 3 
     Configuration of Fire Extinguishing Section 
       [0063]    The configuration of fire extinguishing section  700  in Embodiment 3 of the present invention is described with reference to  FIG. 7 .  FIG. 7  is an enlarged sectional view of a main part of fire extinguishing section  700  in the present embodiment. 
         [0064]    As compared with fire extinguishing section  104  according to Embodiment 1 illustrated in  FIG. 2  and  FIG. 3 , fire extinguishing section  700  illustrated in  FIG. 7  includes closure section  701  in place of closure section  203 . It is to be noted that, in  FIG. 7 , the same reference numerals are attached to the components same as those in  FIG. 2  to  FIG. 4 , and the descriptions thereof are omitted. In addition, the configuration of the in-vehicle fire extinguishing apparatus according to the embodiment of the present embodiment is same as that of  FIG. 1 , and the description thereof is omitted. 
         [0065]    Fire extinguishing section  700  includes fire extinguishing board  201 , void  202 , and closure section  701 . 
         [0066]    Fire extinguishing board  201  is provided with closure section  701 . 
         [0067]    Closure section  701  is formed of a material different from that of fire extinguishing board  201 . Closure section  701  is formed of a material that is melted by a temperature greater than the fire extinguishing start temperature, and closure section  701  is attached to fire extinguishing board  201 . The material of closure section  701  is same as that of closure section  203  of Embodiment 1, and the description thereof is omitted. 
         [0068]    Closure section  701  is provided in wall section  201   a  that separates void  202  from the exterior in fire extinguishing section  700 . As viewed in the thickness cross-section of wall section  201   a , closure section  701  has a form tapering from the exterior toward void  202  of fire extinguishing section  700 . When provided in wall section  201   a , closure section  701  seals void  202  from the exterior. 
         [0069]    Under an environment of a temperature below the fire extinguishing start temperature, the state where closure section  701  is provided in fire extinguishing board  201  is maintained. Thus, the refrigerant having entered void  202  from circulation path  106  is output to circulation path  106  without being emitted to the exterior of fire extinguishing section  700 . In addition, under an environment of the fire extinguishing start temperature or above, closure section  701  is melted by heat. Thus, the refrigerant having entered void  202  from circulation path  106  is emitted out of fire extinguishing section  700 . 
         [0070]    A predetermined pressure is exerted on closure section  701  by the refrigerant having entered void  202 , and therefore, closure section  701  is so provided in fire extinguishing board  201  as not to be dropped off from fire extinguishing board  201  by the pressure of the refrigerant under an environment of a temperature below the fire extinguishing start temperature. 
         [0071]    It is to be noted that the other points of the fire extinguishing method in the present embodiment are same as in Embodiment 1, and the description thereof is omitted. 
       &lt;Effect of the Present Embodiment&gt; 
       [0072]    According to the present invention, fire or the like can be surely extinguished by performing fire extinguishing without using a sensor to detect temperature changes. 
         [0073]    In addition, according to the present embodiment, the closure section has a form tapering from the exterior toward the interior of the fire extinguishing section as viewed in the thickness cross-section of the wall section. Thus, since the size of the surface area contacting the refrigerant can be reduced, the influence of the pressure of the refrigerant can be minimized, and the area heated by fire when fire is caused can be increased. Thus, the closure section can be melted with low energy, and fire can be extinguished at an early stage. 
         [0074]    In addition, according to the present embodiment, when a pressure-regulating valve is provided in the fire extinguishing section, it is possible to prevent the closure section from being dropped off from the fire extinguishing board by the pressure of the refrigerant exerted on the closure section, under an environment of a temperature below the fire extinguishing start temperature. 
       Embodiment 4 
     Configuration of Fire Extinguishing Section 
       [0075]    The configuration of fire extinguishing section  800  in Embodiment 4 of the present invention is described with reference to  FIG. 8 .  FIG. 8  is an enlarged sectional view of a main part of fire extinguishing section  800  in the present embodiment. 
         [0076]    As compared with fire extinguishing section  104  according to Embodiment 1 illustrated in  FIG. 2  and  FIG. 3 , fire extinguishing section  800  illustrated in  FIG. 8  includes closure section  801  in place of closure section  203 . It is to be noted that, in  FIG. 8 , the same reference numerals are attached to the components same as those in  FIG. 2  to  FIG. 4 , and the descriptions thereof are omitted. In addition, the configuration of the in-vehicle fire extinguishing apparatus according to the embodiment of the present embodiment is same as that of  FIG. 1 , and the description thereof is omitted. 
         [0077]    Fire extinguishing section  800  includes fire extinguishing board  201 , void  202  (omitted in  FIG. 8 ), and closure section  801 . 
         [0078]    Fire extinguishing board  201  is provided with closure section  801 . 
         [0079]    Closure section  801  is formed of a material different from that of fire extinguishing board  201 . Closure section  801  is formed of a material that is melted by a temperature greater than the fire extinguishing start temperature, and closure section  801  is attached to fire extinguishing board  201 . The material of closure section  801  is same as that of closure section  203  of Embodiment 1, and the description thereof is omitted. 
         [0080]    Closure section  801  is provided in wall section  201   a  that separates void  202  from the exterior in fire extinguishing section  800 . In closure section  801 , screw thread  801   b  is formed on side wall  801   a , and screw thread  801   b  is threadedly engaged with wall section  201   a . When provided in wall section  201   a , closure section  801  seals void  202  from the exterior. 
         [0081]    Under an environment of a temperature below the fire extinguishing start temperature, the state where closure section  801  is provided in fire extinguishing board  201  is maintained. Thus, the refrigerant having entered void  202  from circulation path  106  is output to circulation path  106  without being emitted to the exterior of fire extinguishing section  800 . In addition, under an environment of the fire extinguishing start temperature or above, closure section  801  is melted by heat. Thus, the refrigerant having entered void  202  from circulation path  106  is emitted out of fire extinguishing section  800 . 
         [0082]    A predetermined pressure is exerted on closure section  801  by the refrigerant having entered void  202 , and therefore, closure section  801  is so provided in fire extinguishing board  201  as not to be dropped off from fire extinguishing board  201  by the pressure of the refrigerant under an environment of a temperature below the fire extinguishing start temperature. 
       &lt;Fire Extinguishing Method&gt; 
       [0083]    A fire extinguishing method in Embodiment 4 of the present invention is described with reference to  FIG. 8 . 
         [0084]    Referring to  FIG. 8 , closure section  801  is heated and melted by fire when fire occurs at device  301 , under an environment of the fire extinguishing start temperature or above. At this time, when screw thread  801   b  of side wall  801   a  is melted, closure section  801  is drops off from fire extinguishing board  201 , or a gap is defined between side wall  801   a  and wall section  201   a . Accordingly, through the through hole defined after closure section  801  drops off, or through the through hole in the form of the gap defined between side wall  801   a  and wall section  201   a , the refrigerant can be emitted out of void  202 . 
         [0085]    It is to be noted that the other points of the fire extinguishing method in the present embodiment are same as in Embodiment 1, and the description thereof is omitted. 
       &lt;Effect of the Present Embodiment&gt; 
       [0086]    According to the present invention, fire or the like can be surely extinguished by performing fire extinguishing without using a sensor to detect temperature changes. 
         [0087]    In addition, according to the present embodiment, since the closure section is threadedly engaged with the fire extinguishing board, it is possible to securely prevent the closure section from dropping off due to the shock and the pressure of the refrigerant applied to the in-vehicle fire extinguishing apparatus. 
         [0088]    In addition, according to the present embodiment, the refrigerant is emitted to the exterior when the screw thread of the side wall of the closure section is melted. Thus, the closure section can be melted with low energy, and fire can be extinguished at an early stage. 
         [0089]    In addition, according to the present embodiment, when a pressure-regulating valve is provided in the fire extinguishing section, it is possible to prevent the closure section from being dropped off from the fire extinguishing board by the pressure of the refrigerant exerted on the closure section, under an environment of a temperature below the fire extinguishing start temperature. 
       Embodiment 5 
     Configuration of Fire Extinguishing Section 
       [0090]    The configuration of fire extinguishing section  900  in Embodiment 5 of the present invention is described with reference to  FIG. 9 .  FIG. 9  is an enlarged sectional view of a main part of fire extinguishing section  900  in the present embodiment. 
         [0091]    As compared with fire extinguishing section  104  according to Embodiment 1 illustrated in  FIG. 2  and  FIG. 3 , fire extinguishing section  900  illustrated in  FIG. 9  includes closure section  901  in place of closure section  203 . It is to be noted that, in  FIG. 9 , the same reference numerals are attached to the components same as those in  FIG. 2  to  FIG. 4 , and the descriptions thereof are omitted. In addition, the configuration of the in-vehicle fire extinguishing apparatus according to the embodiment of the present embodiment is same as that of  FIG. 1 , and the description thereof is omitted. 
         [0092]    Fire extinguishing section  900  includes fire extinguishing board  201 , void  202 , and closure section  901 . 
         [0093]    Fire extinguishing board  201  is provided with closure section  901 . 
         [0094]    Closure section  901  is formed of a material different from that of fire extinguishing board  201 . Closure section  901  is formed of a material that is melted by a temperature greater than the fire extinguishing start temperature, and closure section  901  is attached to fire extinguishing board  201 . The material of closure section  901  is same as that of closure section  203  of Embodiment 1, and the description thereof is omitted. 
         [0095]    Closure section  901  is provided in wall section  201   a  that separates void  202  from the exterior in fire extinguishing section  900 . As viewed in the thickness cross-section of wall section  201   a , closure section  901  has a form tapering from void  202  toward the exterior of fire extinguishing section  900 . When provided in wall section  201   a , closure section  901  seals void  202  from the exterior. 
         [0096]    Under an environment of a temperature below the fire extinguishing start temperature, the state where closure section  901  is provided in fire extinguishing board  201  is maintained. Thus, the refrigerant having entered void  202  from circulation path  106  is output to circulation path  106  without being emitted to the exterior of fire extinguishing section  900 . In addition, under an environment of the fire extinguishing start temperature or above, closure section  901  is melted by heat. Thus, the refrigerant having entered void  202  from circulation path  106  is emitted out of fire extinguishing section  900 . 
         [0097]    It is to be noted that the other points of the fire extinguishing method in the present embodiment are same as in Embodiment 1, and the description thereof is omitted. 
       &lt;Effect of the Present Embodiment&gt; 
       [0098]    According to the present invention, fire or the like can be surely extinguished by performing fire extinguishing without using a sensor to detect temperature changes. 
         [0099]    In addition, according to the present embodiment, the closure section has a form tapering from the interior toward the exterior of the fire extinguishing section as viewed in the thickness cross-section of the wall section. Thus, it is possible to prevent the closure section from dropping off from the fire extinguishing board when the pressure of the refrigerant is increased in the state where fire is not caused. 
         [0100]    In addition, according to the present embodiment, when a pressure-regulating valve is provided in the fire extinguishing section, it is possible to prevent the closure section from being dropped off from the fire extinguishing board by the pressure of the refrigerant exerted on the closure section, under an environment of a temperature below the fire extinguishing start temperature. 
       &lt;Modification Common to All Embodiments&gt; 
       [0101]    While the refrigerant is emitted to the exterior when the closure section is melted in the above-mentioned Embodiments 1 to 5, the present invention is not limited to this, and the refrigerant may be emitted to the exterior when the entirety of the fire extinguishing section is melted. In this case, the closure section is unnecessary. 
         [0102]    In addition, while the fire extinguishing section is provided in the circulation path between the expansion valve and the evaporator in the above-mentioned Embodiment 1 to embodiment 5, the present invention is not limited to this, and the fire extinguishing section may be provided between the evaporator and the compressor. 
         [0103]    In addition, while a plurality of the closure sections are provided in the above-mentioned Embodiments 1 to 5, the present invention is not limited to this, and the number of the closure section may be one. 
         [0104]    This application is entitled to and claims the benefit of Japanese Patent Application No. 2012-068961 dated Mar. 26, 2012, the disclosure of which including the specification, drawings and abstract is incorporated herein by reference in its entirety. 
       INDUSTRIAL APPLICABILITY 
       [0105]    The in-vehicle fire extinguishing apparatus according to the embodiments of the present invention is suitable for use in performing fire extinguishing by utilizing an air conditioning apparatus that heats or cools the vehicle interior. 
       REFERENCE SIGNS LIST 
       [0000]    
       
           100  In-vehicle fire extinguishing apparatus 
           101  Compressor 
           102  Condenser 
           103  Expansion valve 
           104  Fire extinguishing section 
           105  Evaporator 
           106  Circulation path 
           150  Air conditioning section