Method and apparatus for processing exhaust gas in internal combustion engine

Abstract

An exhaust gas processing apparatus ( 26 ) has a bypass passage ( 31 a ) arranged in parallel with exhaust turbine ( 24 b ), an actuator ( 33 ) for opening/closing a bypass valve ( 32 ) to open/close the bypass passage, a fuel supplying valve ( 29 ) for supplying fuel to an exhaust passage ( 22 a ) upstream of a branch portion between the exhaust and bypass passages, a glow plug ( 30 ) for igniting the fuel supplied from the fuel valve, and an ECU ( 13 ) including a processing mode selecting unit ( 13 k ) for selecting a first exhaust gas processing mode for igniting the fuel to introduce the ignited fuel from the bypass passage to an exhaust emission purifier ( 25 ), or a second exhaust gas processing mode for introducing the fuel supplied to the exhaust passage through an exhaust turbine ( 24 b ) to the exhaust emission purifier without igniting the fuel, based upon whether or not there is a flame failure of the fuel.

1 - 14 . (canceled) 
     
     
         15 . A method for processing an exhaust gas introduced to an exhaust emission purifier in a vehicle mounting an internal combustion engine thereon including a bypass valve for opening/closing a bypass passage of the exhaust gas branching from an exhaust passage upstream of an exhaust turbine in an exhaust turbocharger and merging with an exhaust passage positioned between the exhaust turbine and the exhaust emission purifier, a fuel supplying valve for supplying fuel to the exhaust passage upstream of a branch portion between the bypass passage and the exhaust passage, and igniting means for igniting the fuel supplied from the fuel supplying valve in the exhaust passage upstream of the branch portion between the bypass passage and the exhaust passage, comprising:
 a first exhaust gas processing mode for opening the bypass valve, activating the igniting means, and supplying the fuel to the exhaust passage from the fuel supplying valve to ignite the supplied fuel;   a second exhaust gas processing mode for closing the bypass valve and supplying the fuel to the exhaust passage from the fuel supplying valve without activating the igniting means;   a step for determining whether or not there is a flame failure of the fuel when the fuel is ignited by the igniting means; and   a step for selecting the first exhaust gas processing mode in a case where it is determined that there is not the flame failure of the fuel, and selecting the second exhaust gas processing mode in a case where it is determined that there is the flame failure of the fuel.   
     
     
         16 . A method for processing an exhaust gas according to  claim 15 , wherein the step for determining whether or not there is the flame failure of the fuel comprises:
 a step for detecting an exhaust gas temperature;   a step for detecting a flow rate of the exhaust gas flowing into the exhaust emission purifier; and   a step for detecting an oxygen concentration in the exhaust gas.   
     
     
         17 . A method for processing an exhaust gas according to  claim 16 , further comprising:
 a third exhaust gas processing mode for closing the bypass valve, not activating the igniting means, and not supplying the fuel to the exhaust passage from the fuel supplying valve; and   a step for selecting the third exhaust gas processing mode in a case where the detected exhaust gas temperature exceeds a predetermined temperature.   
     
     
         18 . A method for processing an exhaust gas according to  claim 15 , wherein the step for determining whether or not there is a flame failure of the fuel comprises:
 a step for determining whether the vehicle is in the decelerating state or the internal combustion engine is in an idling state, wherein   in a case where it is determined that the vehicle is in the decelerating state or the internal combustion engine is in the idling state, it is determined that there is not the flame failure of the fuel, and in a case where it is determined that neither the vehicle is in the decelerating state nor the internal combustion engine is in the idling state, it is determined that there is the flame failure of the fuel.   
     
     
         19 . A method for processing an exhaust gas according to  claim 18 , further comprising:
 a third exhaust gas processing mode for closing the bypass valve, not activating the igniting means, and not supplying the fuel to the exhaust passage from the fuel supplying valve;   a step for detecting an exhaust gas temperature; and   a step for selecting the third exhaust gas processing mode in a case where the detected exhaust gas temperature exceeds a predetermined temperature.   
     
     
         20 . A method for processing an exhaust gas according to  claim 17 , further comprising:
 a step for determining presence/absence of malfunction in an opening/closing action of the bypass valve based upon a variation in the exhaust gas temperature in a case where the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.   
     
     
         21 . A method for processing an exhaust gas according to  claim 20 , wherein
 the step for determining the presence/absence of the malfunction in the opening/closing action of the bypass valve determines that the opening/closing action of the bypass valve is wrong in a case where the exhaust gas temperature is not lowered at the time the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.   
     
     
         22 . A method for processing an exhaust gas according to  claim 19 , further comprising:
 a step for determining presence/absence of malfunction in an opening/closing action of the bypass valve based upon a variation in the exhaust gas temperature in a case where the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.   
     
     
         23 . A method for processing an exhaust gas according to  claim 22 , wherein
 the step for determining the presence/absence of the malfunction in the opening/closing action of the bypass valve determines that the opening/closing action of the bypass valve is wrong in a case where the exhaust gas temperature is not lowered at the time the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.   
     
     
         24 . An apparatus, in which an exhaust turbocharger and an exhaust emission purifier are incorporated, for processing an exhaust gas introduced from an internal combustion engine to the exhaust emission purifier, comprising:
 a bypass conduit for defining a bypass passage of the exhaust gas branching from an exhaust passage upstream of an exhaust turbine in the exhaust turbocharger and merging with an exhaust passage positioned between the exhaust turbine and the exhaust emission purifier;   a bypass valve mounted on the bypass conduit for opening/closing the bypass passage;   an actuator for performing an opening/closing action of the bypass valve;   a fuel supplying valve for supplying fuel to the exhaust passage upstream of a branch portion between the exhaust passage and the bypass passage;   igniting means for igniting the fuel supplied from the fuel supplying valve to the exhaust passage upstream of the branch portion between the exhaust passage the bypass passage; and   control means for controlling each of operations of the actuator, the fuel supplying valve and the igniting means,   wherein the control means comprises:   a flame failure determining unit for determining whether or not there is a flame failure of the fuel, in a case where the fuel is ignited by the igniting means; and   a processing mode selecting unit for selecting a first exhaust gas processing mode for opening the bypass valve, activating the igniting means and supplying the fuel to the exhaust passage from the fuel supplying valve to ignite the fuel, or a second exhaust gas processing mode for closing the bypass valve and supplying the fuel to the exhaust passage from the fuel supplying valve without activating the igniting means, based upon the determination result of the flame failure determining unit.   
     
     
         25 . An apparatus for processing an exhaust gas according to  claim 24 , further comprising:
 an exhaust gas temperature sensor for detecting a temperature of the exhaust passage;   an exhaust gas flow sensor for detecting a flow rate of the exhaust gas flowing into the exhaust emission purifier; and   an O 2  sensor for detecting an oxygen concentration in the exhaust gas,   wherein the flame failure determining unit in the control means determines whether or not there is the flame failure of the fuel based upon the detected exhaust gas temperature, exhaust gas flow rate and oxygen concentration.   
     
     
         26 . An apparatus for processing an exhaust gas according to  claim 25 , wherein the processing mode selecting unit in the control means selects the third exhaust gas processing mode for closing the bypass valve, not activating the igniting means and not supplying the fuel to the exhaust passage from the fuel supplying valve in a case where the exhaust gas temperature detected by the exhaust gas temperature sensor exceeds a predetermined temperature. 
     
     
         27 . An apparatus for processing an exhaust gas according to  claim 24 , further comprising:
 load detecting means for detecting a load of the internal combustion engine, wherein the flame failure determining unit in the control means determines that there is not the flame failure of the fuel in a case where the load detected by the load detecting means is below a light load and there is the flame failure of the fuel in the other case.   
     
     
         28 . An apparatus for processing an exhaust gas according to  claim 27 , further comprising:
 an exhaust gas temperature sensor for detecting a temperature of the exhaust passage, wherein the processing mode selecting unit in the control means selects the third exhaust gas processing mode for closing the bypass valve, not activating the igniting means and not supplying the fuel to the exhaust passage from the fuel supplying valve in a case where the exhaust gas temperature detected by the exhaust gas temperature sensor exceeds a predetermined temperature.   
     
     
         29 . An apparatus for processing an exhaust gas according to  claim 26 , wherein the control means further comprises:
 a failure determining unit for determining presence/absence of malfunction in an opening/closing action of the bypass valve based upon a variation in the exhaust temperature in a case where the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.   
     
     
         30 . An apparatus for processing an exhaust gas according to  claim 29 , wherein the failure determining unit determines that the opening/closing action of the bypass valve is wrong in a case the exhaust gas temperature is not lowered at the time the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode. 
     
     
         31 . An apparatus for processing an exhaust gas according to  claim 28 , wherein the control means further comprises:
 a failure determining unit for determining presence/absence of malfunction in an opening/closing action of the bypass valve based upon a variation in the exhaust temperature in a case where the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.   
     
     
         32 . An apparatus for processing an exhaust gas according to  claim 31 , wherein the failure determining unit determines that the opening/closing action of the bypass valve is wrong in a case the exhaust gas temperature is not lowered at the time the first exhaust gas processing mode is changed to the second or third exhaust gas processing mode.