Fuel cell system

Abstract

A fuel cell system is disclosed, comprising, within a package, a fuel cell stack; a hydrogen-rich gas supply means configured to supply a hydrogen-rich gas; a combustible gas detector configured to detect leakage of a combustible gas which is the hydrogen-rich gas or a raw fuel gas which is a raw material of the hydrogen-rich gas within the package; a combustible gas guide pipe through which the combustible gas is guided into the package; and a controller; wherein the controller is configured to inject the combustible gas intermittently through the combustible gas guide pipe, and to perform a self-diagnostic process as to whether or not the combustible gas detector is functioning properly.

1 . A fuel cell system comprising, within a package, 
 a fuel cell stack;    a hydrogen-rich gas supply means configured to supply a hydrogen-rich gas;    a combustible gas detector configured to detect leakage of a combustible gas which is the hydrogen-rich gas or a raw fuel gas which is a raw material of the hydrogen-rich gas within said package;    a combustible gas guide pipe through which the combustible gas is guided into said package; and    a controller;    wherein said controller is configured to inject the combustible gas intermittently through said combustible gas guide pipe, and to perform a self-diagnostic process as to whether or not said combustible gas detector is functioning properly.    
     
     
         2 . The fuel cell system according to  claim 1 , wherein 
 said combustible gas guide pipe is configured to branch from a combustible gas passage and to have an end positioned in the vicinity of said combustible gas detector, and    said controller is configured to inject the combustible gas intermittently toward said combustible gas detector through said combustible gas guide pipe, and to perform a self-diagnostic process as to whether or not said combustible gas detector is functioning properly.    
     
     
         3 . The fuel cell system according to  claim 2 , wherein said hydrogen-rich gas supply means is a reformer configured to generate the hydrogen-rich gas from the raw fuel gas.  
     
     
         4 . The fuel cell system according to  claim 3 , wherein said combustible gas guide pipe is configured to branch from a position in a raw fuel gas supply passage connected to an inlet of said reformer.  
     
     
         5 . The fuel cell system according to  claim 3 , wherein said combustible gas guide pipe is configured to branch from a position in a hydrogen supply passage extending between said reformer and an anode of said fuel cell stack, and the raw fuel gas is used under a stopped state of said reformer and the hydrogen-rich gas is used during an operation of said reformer as a gas injected toward said combustible gas detector.  
     
     
         6 . The fuel cell system according to  claim 3 , wherein said combustible gas guide pipe is configured to branch from a position in an exhausted hydrogen passage connected to an anode of said fuel cell stack, and the raw fuel gas filled within said fuel cell stack to purge the hydrogen-rich gas when an operation of the said fuel cell system terminates is used as a gas injected toward said combustible gas detector.  
     
     
         7 . The fuel cell system according to  claim 2 , wherein said controller is configured to close a raw fuel gas valve provided in a raw fuel gas supply passage when said combustible gas detector continues to detect the combustible gas after an elapse of predetermined time after said controller terminates injection of the combustible gas.  
     
     
         8 . The fuel cell system according to  claim 2 , wherein an exhaust fan is provided in said package in the vicinity of said combustible gas detector, and configured to dilute the injected combustible gas with ambient air and to exhaust the diluted combustible gas to outside of said package.  
     
     
         9 . The fuel cell system according to  claim 8 , wherein said controller is configured to operate said exhaust fan intermittently during a stopped state of said fuel cell system to allow leakage of the combustible gas to be monitored during the stopped state of said fuel cell system.  
     
     
         10 . The fuel cell system according to  claim 2 , wherein said controller is configured to perform the self-diagnostic process in such a manner that said controller determines that life of said combustion gas detector has expired when detection sensitivity of said combustible gas detector to the injected combustible gas varies from an initial value and becomes outside an allowable range, and prohibits an operation of said fuel cell system.  
     
     
         11 . The fuel cell system according to  claim 10 , wherein said controller further causes a warning to be displayed when determining that the life of said combustible gas detector has expired.  
     
     
         12 . The fuel cell system according to  claim 10 , wherein said controller is configured to set an injection interval of the combustible gas longer when a variation in the detection sensitivity of said combustible gas detector from an initial value is smaller than a predetermined value, and to set the injection interval shorter when the variation is larger than the predetermined value.  
     
     
         13 . The fuel cell system according to  claim 11 , wherein said controller is configured to set an injection interval of the combustible gas longer when a variation in the detection sensitivity of said combustible gas detector from an initial value is smaller than a predetermined value, and to set the injection interval shorter when the variation is larger than the predetermined value.  
     
     
         14 . The fuel cell system according to  claim 10 , wherein said controller is configured to predict the life of said combustible gas detector from the self-diagnostic process, and to communicate information regarding the predicted life to a maintenance operator.  
     
     
         15 . The fuel cell system according to  claim 11 , wherein said controller is configured to predict the life of said combustible gas detector from the self-diagnostic process, and to communicate information regarding the predicted life to a maintenance operator.