Exhaust state control device for fuel cell for mobile unit

Abstract

An exhaust state control device for a fuel cell for a mobile unit includes an exhaust gas temperature sensor ( 17 ) that measures the temperature of exhaust gas in a discharge passage that discharges the exhaust gas from the main body of the fuel cell, and an ambient temperature sensor ( 19 A) that measures the temperature of ambient air to which exhaust gas is to be discharged. If, based on the difference between the exhaust gas temperature and the ambient temperature, it is determined that white smoke is generated, it is determined whether a condition to reduce white smoke is satisfied. When a first condition is satisfied, a process to reduce white smoke is activated. When a second condition, which requires further reduction of white smoke than under the first condition, is satisfied, a process to suppress the generation of white smoke is activated.

1 . An exhaust state control device for a fuel cell for a mobile unit that detects a state of exhaust gas from a fuel cell mounted on a mobile unit, comprising:
 an exhaust gas temperature sensor that measures, as a state of the exhaust gas, a temperature of the exhaust gas in a discharge passage that discharges the exhaust gas from a main body of the fuel cell;   an ambient temperature sensor that measures, as a state of the ambient air, a temperature of the ambient air to which the exhaust gas is to be discharged;   a motion sensor that detects movement of the mobile unit;   a white smoke generation determination section that determines whether white smoke is generated based on a relationship between the state of exhaust gas and the state of ambient air;   a condition determination section that determines whether a predetermined condition to reduce white smoke is satisfied based on a detection signal from the motion sensor when the white smoke generation determination section determines that white smoke is generated; and   a control section that activates a process to reduce white smoke if the condition determination section determines that the predetermined condition is satisfied.   
   
   
       2 . The exhaust state control device for a fuel cell according to  claim 1 , further comprising:
 an operation state sensor that detects an operating state of an operating section that operates the mobile unit; and   a sensor that senses a surrounding environmental state of the mobile unit,   wherein the condition determination section determines whether the predetermined condition to reduce white smoke is satisfied based on at least one of the detected moving state of the mobile unit, the detected operating state of the operating section that operates the mobile unit, and the detected surrounding environmental state of the mobile unit.   
   
   
       3 . The exhaust state control device for a fuel cell according to  claim 1 , wherein the control section activates a process to reduce white smoke when the condition determination section determines that a first predetermined condition is satisfied, and activates a process to further reduce generation of white smoke than when the first predetermined condition is determined to be satisfied, if the condition determination section determines that a second predetermined condition is satisfied. 
   
   
       4 . The exhaust state control device for a fuel cell according to  claim 2 , wherein the control section activates a process to reduce white smoke when the condition determination section determines that a first predetermined condition is satisfied, and activates a process to further reduce generation of white smoke than when the first predetermined condition is determined to be satisfied, if the condition determination section determines that a second predetermined condition is satisfied. 
   
   
       5 . The exhaust state control device for a fuel cell according to  claim 4 , 
     wherein the white smoke generation determination section determines whether white smoke is generated according to the difference between the exhaust gas temperature and the ambient air temperature. 
   
   
       6 . The exhaust state control device for a fuel cell according to  claim 4 , further comprising 
     an ambient humidity sensor that measures a humidity of the ambient air to which the exhaust gas is to be discharged,
 wherein the white smoke generation determination section determines whether white smoke is generated according to the difference between the exhaust gas temperature and the ambient air temperature, and the ambient air humidity. 
 
   
   
       7 . The exhaust state control device for a fuel cell according to  claim 4 , wherein:
 the first predetermined condition is satisfied if either one of the conditions, where a moving speed of the mobile unit is determined to be at or below a predetermined value and where a visibility of white smoke around the mobile unit is determined to be higher than that in a reference environment, is satisfied; and   the second predetermined condition is satisfied if both the conditions, where the moving speed of the mobile unit is determined to be at or below the predetermined value and where the visibility of white smoke around the mobile unit is determined to be higher than that in the reference environment, are satisfied.   
   
   
       8 . The exhaust state control device for a fuel cell according to  claim 7 , wherein the condition where the moving speed of the mobile unit is determined to be at or below the predetermined value includes a state where the mobile unit is stationary. 
   
   
       9 . The exhaust state control device for a fuel cell according to  claim 7 , wherein the moving speed of the mobile unit is an absolute speed of the mobile unit or a relative speed between the mobile unit and the ambient air around the mobile unit. 
   
   
       10 . The exhaust state control device for a fuel cell according to  claim 4 , wherein:
 the mobile unit is a vehicle;   the first predetermined condition is satisfied if either one of conditions, where a shift lever is determined to be in a parking position and where a visibility of white smoke around the mobile unit is determined to be higher than that in a reference environment, is satisfied; and   the second predetermined condition is satisfied if both the conditions, where the shift lever is determined to be in the parking position and where the visibility of white smoke around the mobile unit can be determined to be higher than that in the reference environment, are satisfied.   
   
   
       11 . The exhaust state control device for a fuel cell according to  claim 4 , wherein:
 the first predetermined condition is satisfied if either one of conditions, a condition where the white smoke generation determination section determines that white smoke is generated, or a condition where a moving speed of the mobile unit is at or below a predetermined value and where a visibility of white smoke around the mobile unit is determined to be lower than that in a reference environment, is satisfied; and   the second predetermined condition is satisfied if both the conditions, where the moving speed of the mobile unit is determined to be at or below the predetermined value and where the visibility of white smoke around the mobile unit is determined to be higher than that in the reference environment, are satisfied.   
   
   
       12 . The exhaust state control device for a fuel cell according to  claim 11 , wherein if the conditions, where the white smoke generation determination section determines that white smoke is generated, and where the moving speed of the mobile unit is at or below the predetermined value and the visibility of white smoke around the mobile unit is determined to be lower than that in the reference environment, are satisfied, the process to reduce white smoke, which is performed when the condition determination section determined that the first predetermined condition has been satisfied, is performed in different level. 
   
   
       13 . The exhaust state control device for a fuel cell according to  claim 4 , wherein:
 the first predetermined condition is satisfied if either one of conditions, where a vision of an operator who operates the mobile unit is determined to be affected by white smoke and where a visibility of white smoke around the mobile unit is higher than that in a reference environment, is satisfied; and   the second predetermined condition is satisfied if both the condition, where the vision of the operator who operates the mobile unit is determined to be affected by white smoke and where the visibility of white smoke around the mobile unit is higher than that in the reference environment, are satisfied.   
   
   
       14 . The exhaust state control device for a fuel cell according to  claim 7 , wherein the reference environment includes at least one of a daytime environment and a non-rainy environment. 
   
   
       15 . The exhaust state control device for a fuel cell according to  claim 14 , wherein:
 the mobile unit is a vehicle;   the operating state of the operating section is determined based on whether a headlight is on;   the surrounding environmental state is determined based on at least one of: whether a darkness detection signal for an automatic light is on; whether a current time is after a sunset and before a sunrise; whether a signal from a global positioning system cannot be received; whether a wiper is on; whether a rain sensing signal is on; and whether a detection value of the ambient humidity sensor exceeds a predetermined value; and   the condition determination section determines that the reference environment is the daytime or non-rainy environment if at least one of the determined states above is satisfied.   
   
   
       16 . The exhaust state control device for a fuel cell according to  claim 13 , wherein the vision of the operator is determined to be affected by white smoke if the mobile unit advances in a discharging direction of the exhaust gas. 
   
   
       17 . The exhaust state control device for a fuel cell according to  claim 13 , wherein:
 the mobile unit is a vehicle; and   it is determined that the condition where the white smoke interferes with vision of the operator of the mobile unit is satisfied when at least one of the shift lever is in a reverse position and the parking brake is off.   
   
   
       18 . The exhaust state control device for a fuel cell according to  claim 4 , wherein the process to reduce white smoke is at least one of a process to control the exhaust gas temperature and a process to control a flow rate of the exhaust gas at an air electrode side of the fuel cell. 
   
   
       19 . The exhaust state control device for a fuel cell according to  claim 18 , wherein discharge of the exhaust gas at the air electrode side is controlled such that a limit of the flow rate of the exhaust gas decreases as the moving speed of the mobile unit decreases. 
   
   
       20 . The exhaust state control device for a fuel cell according to  claim 18 , wherein a pressure or the flow rate of the exhaust gas at the air electrode side is controlled such that the limit of the flow rate of the exhaust gas increases as the pressure of the exhaust gas increases. 
   
   
       21 . The exhaust state control device for a fuel cell according to  claim 4 , wherein the process to reduce the generation of white smoke, which is performed when the condition determination section determines that the second predetermined condition is satisfied, includes at least one of stopping scavenging air and shutting off a hydrogen supply pressure to the fuel cell.