Control apparatus for internal combustion engine

Abstract

A control apparatus for an internal combustion engine in the present invention includes a DPF installed in an exhaust passage and a DOC installed in the exhaust passage on the upstream side of the DPF. The control apparatus changes an engine control parameter so as to facilitate NO 2 -based regeneration when it is determined that an operating state in which the NO 2 -based regeneration speed is higher than a predetermined threshold value is established during operation of the internal combustion engine.

1 . A control apparatus for an internal combustion engine, comprising:
 a particulate filter that is installed in an exhaust passage of the internal combustion engine and traps particulate filter; and   a controller that is programmed to:   produce NO 2  in exhaust gas supplied to the particulate filter;   estimate an NO 2 -based regeneration speed that is a speed of regeneration of the particulate filter using NO 2 , during operation of the internal combustion engine;   determine whether or not an operating state in which the NO 2 -based regeneration speed is higher than a predetermined threshold value is established during operation of the internal combustion engine; and   change an engine control parameter so that when determining that the operation state in which the NO 2 -based regeneration speed is higher than the threshold value is established, an amount of NO 2  supplied to the particulate filter and a temperature of the particulate filter are increased,   wherein the controller determines that the operating state in which the NO 2 -based regeneration speed is higher than the threshold value has been established when a present temperature of the particulate filter is higher than a predetermined temperature threshold value and a present amount of accumulation of particulate matter in the particulate filter is larger than a predetermined accumulation amount threshold value and a present amount of NO 2  flown into the particulate filter is larger than a predetermined NO2 amount threshold value.   
     
     
         2 . The control apparatus for the internal combustion engine according to  claim 1 ,
 wherein even when the operation state in which the NO 2 -based regeneration speed is higher than the threshold value is established, the controller prohibits a change in the engine control parameter in a case in which an outside air temperature is lower than or equal to a predetermined value and/or an engine cooling water temperature is lower than or equal to a predetermined value.   
     
     
         3 . The control apparatus for the internal combustion engine according to  claim 1 ,
 wherein even when the operation state in which the NO 2 -based regeneration speed is higher than the threshold value is established, the controller prohibits a change in the engine control parameter in a case in which torque control is performed so that a torque of the internal combustion engine is maintained.   
     
     
         4 . The control apparatus for the internal combustion engine according to  claim 1 ,
 wherein even when the operation state in which the NO 2 -based regeneration speed is higher than the threshold value is established, the controller prohibits a change in the engine control parameter in a case in which a vehicle on which the internal combustion engine is mounted is traveling in an urban area.   
     
     
         5 . The control apparatus for the internal combustion engine according to  claim 1 ,
 wherein the controller suspends a change in the engine control parameter when the operation state in which the NO 2 -based regeneration speed is higher than the threshold value has stopped being established during a period in which the change in the engine control parameter is being performed.   
     
     
         6 . The control apparatus for the internal combustion engine according to  claim 3 ,
 wherein a case in which cruise control to control the torque of the internal combustion engine is performed so that a speed of a vehicle is maintained corresponds to the case in which the torque control is performed so that the torque of the internal combustion engine is maintained.   
     
     
         7 . A control apparatus for an internal combustion engine, comprising:
 a particulate filter that is installed in an exhaust passage of the internal combustion engine and traps particulate filter;   NO 2  production means for producing NO 2  in exhaust gas supplied to the particulate filter;   NO 2 -based regeneration speed estimation means for estimating an NO 2 -based regeneration speed that is a speed of regeneration of the particulate filter using NO 2 , during operation of the internal combustion engine;   operating state determination means for determining whether or not an operating state in which the NO 2 -based regeneration speed is higher than a predetermined threshold value is established during operation of the internal combustion engine; and   control parameter change means for changing an engine control parameter so that when the operation state in which the NO 2 -based regeneration speed is higher than the threshold value is determined to be established by the operation state determination means, an amount of NO 2  supplied to the particulate filter and a temperature of the particulate filter are increased,   wherein the operating state determination means determines that the operating state in which the NO 2 -based regeneration speed is higher than the threshold value has been established when a present temperature of the particulate filter is higher than a predetermined temperature threshold value and a present amount of accumulation of particulate matter in the particulate filter is larger than a predetermined accumulation amount threshold value and a present amount of NO 2  flown into the particulate filter is larger than a predetermined NO2 amount threshold value.