Control unit for internal combustion engine

Abstract

A control unit for an internal combustion engine can activate a three-way catalyst at the early stage and can lessen the deterioration of the exhaust in an internal combustion engine such as HC, CO, and NOx, etc. from the exhaust gas when starting. The control unit for an internal combustion engine is provided with the three-way catalyst and HC adsorbent on an exhaust side. The control unit alternately controls the A/F between a rich state and a lean state in order to quicken the activation of the three-way catalyst when the internal combustion engine starts.

What is claimed is:  
     
         1 . A control unit for an internal combustion engine including the three way catalyst and HC adsorbent on an exhaust side, 
 wherein said control unit alternately controls the A/F between a rich state and a lean state in order to quicken the activation of said three way catalyst when said internal combustion engine starts.    
     
     
         2 . A control unit for an internal combustion engine including the three way catalyst on an exhaust side, 
 wherein control unit has a means for detecting completion of the evaporation of moisture in said three way catalyst directly or indirectly, and    wherein control unit alternately controls the A/F between a rich state and a lean state in order to quicken the activation of said three way catalyst after the completion of the evaporation of moisture in said three way catalyst is detected.    
     
     
         3 . The control unit for an internal combustion engine according to  claim 2 , 
 wherein the ignition time is retarded for the period until moisture in said three way catalyst evaporates directly after the start of said internal combustion engine.    
     
     
         4 . A control unit for an internal combustion engine including the three way catalyst on an exhaust side, 
 wherein control unit has a means for detecting the temperature of said three way catalyst directly or indirectly, and    wherein control unit alternately controls the A/F between a rich state and a lean state in order to quicken the activation of the three way catalyst when the temperature of said three way catalyst is a value within the fixed range.    
     
     
         5 . A control unit for an internal combustion engine including the three way catalyst on an exhaust side, 
 wherein control unit has a means for detecting the operating state of the internal combustion engine, and    wherein control unit alternately controls the A/F between a rich state and a lean state in order to quicken the activation of the three way catalyst based on the operating state.    
     
     
         6 . A control unit for an internal combustion engine including the three way catalyst and HC adsorbent on an exhaust side in the order, 
 wherein control unit has a means for detecting the temperature of said HC adsorbent directly or indirectly, and    wherein control unit alternately controls the A/F between a rich state and a lean state in order to change the temperature of said HC adsorbent.    
     
     
         7 . The control unit for an internal combustion engine according to  claim 6 , 
 wherein control unit alternately controls the A/F between a rich state and a lean state when the temperature of said HC adsorbent is within the fixed range.    
     
     
         8 . A control unit for an internal combustion engine including a catalyst which has the three way catalyst and HC adsorbent in the same carrier on an exhaust side, 
 wherein control unit alternately controls the A/F between a rich state and a lean state in order to change the temperature of said HC adsorbent.