Abstract:
A combustor support structure of the present invention supports, at a predetermined position of a fixation member, a combustor having a combustion section which burns supplied fuel and air, and an exhaust pipe which discharges outside, combustion gas generated by burning the fuel and air. The combustor support structure includes: a first fixing section provided in the combustor; a second fixing section provided in the fixation member and fixed to the first fixing section; a first stress-absorbing section provided in the combustor; a second stress-absorbing section provided in the fixation member and connected to the first stress-absorbing section; and a stress-absorbing member interposed between the first stress-absorbing section and the second stress-absorbing section, and absorbing stress caused by thermal expansion of the combustor.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a combustor support structure which supports a combustor at a predetermined position.  
         [0003]     2. Description of the Related Art  
         [0004]     Japanese Patent Application Laid-Open No. 2002-364849 discloses a conventional combustor. This combustor includes an air passage through which air is supplied into the combustor, and a fuel nozzle which is disposed in the air passage and which includes an ejection opening through which fuel is ejected. Fuel and air supplied into the air passage are mixed and burned in the combustion chamber, and generated combustion gas is discharged out through an exhaust pipe.  
         [0005]     When actually operating such a combustor, it must be fixed to a predetermined position to maintain a stable combustion state.  
       SUMMARY OF THE INVENTION  
       [0006]     However, a downstream side of the combustion gas from the combustion chamber of the combustor is heated to a high temperature by combustion gas passing through the downstream side, thereby thermally expanding the combustor and the exhaust pipe. That is, the shapes of the combustor and the exhaust pipe are varied due to temperature variations caused between a state where the combustor is stopped and is sufficiently cooled and a state where the combustor is operated and heated. Therefore, it is difficult to safely and reliably support the conventional combustor at a predetermined position.  
         [0007]     The present invention has been achieved in view of the above circumstances, and it is an object of the invention to provide a combustor support structure which safely and reliably supports a combustor whose outside dimension is varied due to thermal stress caused between the stopped state and the operating state of the combustor.  
         [0008]     According to one aspect of the present invention, there is provided a combustor support structure which supports, at a predetermined position of a fixation member, a combustor having a combustion section which burns supplied fuel and air, and an exhaust pipe which discharges outside, combustion gas generated by burning the fuel and air, the combustor support structure comprising: a first fixing section provided in the combustor; a second fixing section provided in the fixation member and fixed to the first fixing section; a first stress-absorbing section provided in the combustor; a second stress-absorbing section provided in the fixation member and connected to the first stress-absorbing section; and a stress-absorbing member interposed between the first stress-absorbing section and the second stress-absorbing section, the stress-absorbing member absorbing stress caused by thermal expansion of the combustor. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]     The invention will now be described with reference to the accompanying drawings wherein;  
         [0010]      FIG. 1  is a schematic view showing a structure of a combustor having a combustor support structure of the present invention;  
         [0011]      FIG. 2  is an enlarged view of a portion of the combustor support structure of the invention, which supports the combustor; and  
         [0012]      FIG. 3  is an enlarged view of a portion of the combustor support structure of the invention, which supports the combustor in a state where the combustor is thermally expanded. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0013]     Hereinafter, description will be made of embodiments of the present invention with reference to the drawings.  
         [0014]     A combustor  10  supported by a combustor support structure  1  of this embodiment constitutes a portion of a fuel cell system of a fuel cell vehicle. The combustor  10  is supported by a sub-frame  30  as a fixation member together with a fuel cell stack and a humidifier, and is disposed on a floor of the vehicle in a state where the combustor  10  is supported by the sub-frame  30 .  
         [0015]     The combustor  10  is used for burning exhaust hydrogen included in gas discharged when a fuel cell stack is purged and for discharging the burnt exhaust hydrogen outside. Further, the combustor  10  is used such that when the fuel cell is actuated at low temperature environment, hydrogen is burned, and heat of generated combustion gas is utilized to warm equipment such as the stack.  
         [0016]     As shown in  FIG. 1 , the combustor  10  includes a combustor body  11  having a combustion section  15  which burns air-fuel mixture, and a heat exchanger  20  which transmits heat of the combustion gas to cooling water of the fuel cell stack. The cooling water circulates in the heat exchanger  20  when the combustion gas generated in the combustion section  15  passes through the heat exchanger  20 . A mixing section  14  which uniformly mixes air and fuel supplied into the combustor body  11  is connected to the combustor body  11 . The air and fuel mixed by the mixing section  14  are sent into the combustor body  11 . An air-supply port  12  to which air is supplied from an air-supply apparatus (not shown) through a cathode (not shown) of the fuel cell stack (not shown) and the humidifier (not shown) are connected to the mixing section  14 . Further, a fuel-supply section  13  to which fuel is supplied from the fuel-supply apparatus (not shown) through an anode (not shown) of the fuel cell stack are connected to the mixing section  14 . Air and fuel are supplied to the mixing section  14  through the air-supply port  12  and the fuel-supply section  13 . An exhaust pipe  17  for discharging outside the combustion gas which passes through the heat exchanger  20  is connected to the heat exchanger  20 . That is, the heat exchanger  20  is interposed between the exhaust port  16  and the exhaust pipe  17  of the combustor  10 .  
         [0017]     In this embodiment, air is supplied to the combustor  10  from the air-supply port  12  provided on one end of the substantially cylindrical combustor body  11 , and fuel is supplied to the combustor  10  from the fuel-supply section  13  provided near the air-supply port  12 , and the air and fuel are uniformly mixed by the mixing section  14 . Thereafter, the air-fuel mixture sent from the mixing section  14  is burned in the combustion section  15 , and the combustion gas is discharged outside from the other end of the combustor body  11  through the exhaust pipe  17 .  
         [0018]     The air-supply port  12  is formed at its periphery with a body-side flange  18  as a body-side fixing section. A plurality of stud bolts  18   a  project from the body-side flange  18 . The humidifier (not shown) is connected to the air-supply port  12 , and is fixed to the sub-frame (fixation member)  30 . A fixation member-side flange as a fixation member-side fixing section is formed on a portion of the humidifier. That is, nuts (not shown) are fastened to the stud bolts  18   a,  the body-side flange  18  and the fixation member-side flange are connected to each other, thereby fixing the combustor  10  to the sub-frame  30  through the humidifier.  
         [0019]     As shown in  FIG. 1 , body-side stays  19  having high rigidity as body-side stress-absorbing sections are fixed near a connected portion between the exhaust pipe  17  and the heat exchanger  20  and in a substantially central portion of the exhaust pipe  17 , respectively. As shown in  FIG. 2  and  FIG. 3 , the sub-frame  30  is provided with a fixation-side stay  33  having high rigidity as a stress-absorbing section on the side of the fixation member (sub-frame). The fixation-side stay  33  is opposed to the body-side stay  19  when the combustor  10  is fixed.  
         [0020]     A mount  40  as a stress-absorbing member includes two plates  41  having high rigidity, and an absorber  42  made of elastomer, rubber or the like having resilience and elasticity. The two plates  41  are integrally formed such as to sandwich the absorber  42 . Stud bolts  41   a  outwardly project from the plates  41 .  
         [0021]     The mount  40  is fastened to the body-side stay  19  and the fixation-side stay  33  by fastening nuts  41   b  to the stud bolts  41   a  which are inserted into mounting holes  19   a  and  33   a  formed in the body-side stay  19  and the fixation-side stay  33 . When the temperature of the combustor  10  is low, the absorber  42  of the mount  40  is not deformed as shown in  FIG. 2 , and the mount  40  supports the combustor  10  while keeping the formed shape thereof. When the combustor  10  is operated and the combustion section  15  is heated, the combustion section  15  and the exhaust pipe  17  are deformed in the longitudinal direction due to thermal expansion, the absorber  42  of the mount  40  is resiliently deformed, and the mount  40  supports the combustor  10  in a state where thermal stress is absorbed as shown in  FIG. 3 .  
         [0022]     As explained above, according to the combustor support structure  1  of the embodiment of the present invention, body-side fixing section (body-side flange)  18  provided on the combustor  10  and the fixation member-side fixing section (fixation member-side flange) provided on the fixation member (sub-frame)  30  are connected to each other, and the body-side stress-absorbing section (body-side stay)  19  provided on the combustor  10  and the fixation member-side stress-absorbing section (fixation-side stay)  33  provided on the fixation member  30  are connected to each other with the stress-absorbing member  40 . Therefore, even when the operating combustor  10  is thermally expanded, the thermal expansion is absorbed by the stress-absorbing member  40  and thus, the thermal stress acting on the fixation member  30  and the combustor  10  can be moderated, and the combustor  10  can safely and reliably be supported.  
         [0023]     A portion of the combustor  10  closer to the air-supply port  12  than the combustion section  15  is fixed by the body-side fixing section  18 , and a portion of the combustor  10  closer to the exhaust pipe  17  than the combustion section  15  is supported by the body-side stress-absorbing section  19 . Therefore, equipment and pipes disposed closer to the air-supply port  12  than the combustion section  15  need not have stress absorbing function, and the entire apparatus can be simplified.  
         [0024]     Since the heat exchanger  20  is provided between the combustor body  11  and the exhaust pipe  17 , waste heat of combustion gas is absorbed and utilized by the heat exchanger  20 , the machinery efficiency is enhanced, the temperature of the combustion gas which has passed through the heat exchanger  20  is lowered, and the temperature of the exhaust pipe  17  is lowered. With this structure, heat resistance required for the stress-absorbing member  40  is moderated, various materials can be used as the stress-absorbing member  40 , and the cost of the stress-absorbing member  40  can be reduced.  
         [0025]     The absorber  42  of the present embodiment is made of elastomer, rubber or the like having resilience and elasticity, but the same effect can be obtained even if a metal thin plate is corrugated so that the resilience and elasticity can be obtained, and the combustor  10  is supported by this corrugated thin plate. If metal is used as the absorber  42 , even under a temperature condition where the heat exchanger  20  is not provided and the exhaust pipe  17  is heated to high temperature and elastomer, rubber or the like can not be used, the combustor can be supported safely and reliably.  
         [0026]     The entire content of a Japanese Patent Application No. P2003-349418 with a filing date of Oct. 8, 2003 is herein incorporated by reference.  
         [0027]     Although the invention has been described above by reference to certain embodiments of the invention, the invention is not limited to the embodiments described above will occur to these skilled in the art, in light of the teachings. The scope of the invention is defined with reference to the following claims.