Catalyst warming apparatus of internal combustion engine

Abstract

It is an object of the present invention to provide a technology capable of producing an appropriate combustible mixture in an apparatus for heating an exhaust-purifying catalyst disposed in an exhaust passage of an internal combustion engine, without providing a special pre-mixing chamber for mixing fuel and air, by burning the combustible mixture in the exhaust passage upstream of the exhaust-purifying catalyst when the exhaust-purifying catalyst is inactive. To achieve this object, in a catalyst warming apparatus of the internal combustion engine according to the present invention, a sub exhaust-purifying catalyst is disposed in the exhaust passage upstream of a main exhaust-purifying catalyst, and the fuel components and air are discharged from the internal combustion engine when the main exhaust-purifying catalyst needs to be warmed up. Thus, the fuel components and air discharged from the internal combustion engine are mixed into a combustible mixture in the sub exhaust-purifying catalyst, and the resultant combustible mixture is burned upstream of the main exhaust-purifying catalyst.

What is claimed is:  
     
         1 . A catalyst warming apparatus of an internal combustion engine, comprising: 
 an exhaust passage connected to the internal combustion engine;    a main exhaust-purifying catalyst provided in said exhaust passage for purifying exhaust gas flowing in said exhaust passage;    a sub exhaust-purifying catalyst provided in said exhaust passage upstream of said main exhaust-purifying catalyst for purifying the exhaust gas flowing in said exhaust passage;    ignition means provided in said exhaust passage between said main and sub exhaust-purifying catalysts; and    combustible-component supply means for supplying fuel and air to the exhaust passage upstream of said sub exhaust-purifying catalyst;    wherein said combustible-component supply means supplies the fuel and air to the exhaust passage upstream of said sub exhaust-purifying catalyst immediately after completion of starting of said internal combustion engine.    
     
     
         2 . A catalyst warming apparatus of an internal combustion engine according to  claim 1 , wherein said combustible-component supply means supplies the fuel and air to the exhaust passage upstream of said sub exhaust-purifying catalyst, by causing at least one of the cylinders of said internal combustion engine to discharge exhaust gas containing unburned fuel, and, at the same time, causing the remainder of the cylinders to discharge exhaust gas containing unburned air immediately after completion of starting of said internal combustion engine.  
     
     
         3 . A catalyst warming apparatus of an internal combustion engine according to  claim 2 , wherein said combustible-component supply means causes said at least one of the cylinders to discharge the exhaust gas containing unburned fuel, by burning a rich mixture in said at least one of the cylinders.  
     
     
         4 . A catalyst warming apparatus of an internal combustion engine according to  claim 2 , wherein said combustible-component supply means causes said at least one of the cylinders to discharge the exhaust gas containing unburned fuel, by injecting main fuel for combustion from a fuel injection valve of said at least one of the cylinders, and then, injecting sub fuel therefrom.  
     
     
         5 . A catalyst warming apparatus of an internal combustion engine according to  claim 2 , wherein said combustible-component supply means causes said at least one of the cylinders to discharge the exhaust gas containing unburned fuel, by causing low-temperature combustion to occur in said at least one of the cylinders.  
     
     
         6 . A catalyst warming apparatus of an internal combustion engine according to  claim 2 , wherein said combustible-component supply means causes said remainder of the cylinders to discharge the exhaust gas containing unburned air, by burning a lean mixture in said remainder of the cylinders.  
     
     
         7 . A catalyst warming apparatus of an internal combustion engine according to  claim 2 , wherein said combustible-component supply means causes said remainder of the cylinders to discharge the exhaust gas containing unburned air, by inhibiting actuation of a fuel injection valve of each of said remainder of the cylinders.  
     
     
         8 . A catalyst warming apparatus of an internal combustion engine according to  claim 1 , wherein said combustible-component supply means supplies the fuel and air to the exhaust passage upstream of said sub exhaust-purifying catalyst, by burning a rich mixture in every cylinder of said internal combustion engine as well as supplying sub air to the exhaust passage upstream of said sub exhaust-purifying catalyst immediately after completion of starting of said internal combustion engine.