Exhaust emission purifier of internal combustion engine

Abstract

An object of this invention is to prevent components such as NOx and H2S being emitted when starting a vehicle and improve exhaust emissions by utilizing information of a navigation system. A navigation system mounted in the vehicle is connected to an ECU. The ECU predicts whether a stopping time of the internal combustion engine is near based on the current position and travel history of the vehicle obtained from the navigation system. When a stopping time is near, the ECU executes rich spike control prior to the stopping time to thereby perform a regeneration process of the NOx catalyst. Thus, NOx components or sulfur components remaining in the catalyst can be eliminated before stopping the internal combustion engine. Accordingly, even if warming up is performed when the engine is next started, emission of NOx or hydrogen sulfide can be avoided.

1 . An exhaust emission purifier of an internal combustion engine, comprising:
 a NOx catalyst that is provided in an exhaust passage of an internal combustion engine that is mounted in a vehicle, and that stores and reduces NOx components in exhaust gas;   information acquiring means that acquires information including a current position and a travel history of the vehicle as travel information; and   catalyst regeneration control means that, when it is predicted that a stopping time of the internal combustion engine is near based on the travel information, makes an exhaust air-fuel ratio of the internal combustion engine richer than at a time of normal operation.   
     
     
         2 . The exhaust emission purifier of an internal combustion engine according to  claim 1 , wherein the catalyst regeneration control means predicts whether or not a stopping time of the internal combustion engine is near by comparing a current position of the vehicle that is obtained as the travel information and a destination that is registered in the information acquiring means. 
     
     
         3 . The exhaust emission purifier of an internal combustion engine according to  claim 1 , wherein the catalyst regeneration control means predicts whether or not the internal combustion engine will be stopped for a period that is long enough to require a warming up operation based on the travel history of the vehicle that is obtained as the travel information, and when the catalyst regeneration control means predicts that the stop time will be long, the catalyst regeneration control means enriches the exhaust air-fuel ratio prior to stopping. 
     
     
         4 . The exhaust emission purifier of an internal combustion engine according to  claim 1 , further comprising:
 NOx storage amount acquiring means that acquires an amount of NOx components stored in the NOx catalyst;   wherein when a storage amount of the NOx components is greater than or equal to a NOx reference determination value, the catalyst regeneration control means enriches the exhaust air-fuel ratio in order to perform a reduction process for the NOx components.   
     
     
         5 . The exhaust emission purifier of an internal combustion engine according to  claim 1 , further comprising:
 sulfur adherence amount acquiring means that acquires an amount of sulfur components adhered to the NOx catalyst;   wherein when an adherence amount of the sulfur components is greater than or equal to a sulfur reference determination value, the catalyst regeneration control means enriches the exhaust air-fuel ratio in order to perform a desorption process for the sulfur components.   
     
     
         6 . The exhaust emission purifier of an internal combustion engine according to  claim 5 , wherein when performing the desorption process for the sulfur components, the catalyst regeneration control means enriches the exhaust air-fuel ratio over a longer time period than a time period required for a reduction process for NOx components stored in the NOx catalyst. 
     
     
         7 . The exhaust emission purifier of an internal combustion engine according to  claim 5 , wherein the catalyst regeneration control means adjusts an execution state of the desorption process based on road traffic information or a time of travel that are obtained as the travel information. 
     
     
         8 . The exhaust emission purifier of an internal combustion engine according to  claim 1 , wherein the catalyst regeneration control means estimates a temperature of the internal combustion engine at a time of a next start-up based on at least one item of information among items of information relating to a current position of the vehicle and a current date that are obtained as the travel information and an outside air temperature, and previously adjusts an amount of NOx components that remain in the NOx catalyst when the internal combustion engine stops in accordance with the estimated temperature.