Control device of an engine

Abstract

There is provided a control device for controlling an engine operation such that the engine is operated at a predetermined fuel consumption in accordance with a requested output. The engine comprises an electric motor and an exhaust gas purification catalyst. When an air fuel ratio of an exhaust gas should be made rich to restore an ability of purification of the catalyst, the device controls the motor operation such that the air fuel ratio of the exhaust gas is made rich while the engine output is caused to be decreased and the shortage of the engine output relative to the requested output is supplemented by the motor output to totally output the requested output.

1 . A control device for controlling an operation of an engine such that the engine is operated at a predetermined fuel consumption in accordance with a requested output, the engine comprising an electric motor and an exhaust gas purification catalyst arranged in an exhaust passage of the engine for purifying components included in an exhaust gas wherein, when the engine is operated at a predetermined fuel consumption and the output of the engine does not reach a requested output, the control device controls an operation of the electric motor such that the shortage of the output of the engine relative to the requested output is supplemented by an output of the electric motor to totally output the requested output and, on the other hand, when the engine is operated at a predetermined fuel consumption and the output of the engine exceeds the requested output, the control device controls the operation of the electric motor such that the excess output of the engine relative to the requested output is stored as an electric power to totally output the requested output and, further, when an air fuel ratio of an exhaust gas should be made rich to restore an ability of purification of the catalyst, the control device controls the operation of the electric motor such that the air fuel ratio of the exhaust gas is made rich while the output of the engine is caused to be decreased and the shortage of the output of the engine relative to the requested output is supplemented by the output of the electric motor to totally output the requested output.  
     
     
         2 . A control device set forth in  claim 1  wherein, when the air fuel ratio of the exhaust gas should be made rich to restore the ability of purification of the catalyst, the control device controls the operation of the engine such that the operation of the engine is stopped just after the output of the engine is caused to be decreased and, shortly thereafter, the air fuel ratio of the exhaust gas is made rich.  
     
     
         3 . A control device as set forth in  claim 1 , wherein the catalyst comprises a NO x  absorbent which absorbs a NO x  included in the exhaust gas if the air fuel ratio of the exhaust gas flowing into the catalyst is lean and which releases the absorbed NO x  if the air fuel ratio of the exhaust gas flowing into the catalyst becomes stoichiometric or rich.