Control apparatus for internal combustion engine including valve stop mechanism

摘要

A control apparatus which is capable of determining an abnormality of a stopping operation of an exhaust valve without using a dedicated sensor for detecting the abnormality in an internal combustion engine including a valve stop mechanism capable of maintaining the exhaust valve and an intake valve in a valve closed state is provided. It is discriminated whether or not there is a change to a rich side of a air fuel ratio of gas detected by a main A/F sensor at the time of a fuel cut for all the cylinders associated with a valve stop request for the exhaust valves and intake valves of all the cylinders. Then, when it is discriminated that there is the change to the rich side of the air fuel ratio of the gas, it is determined that the stopping operation of the exhaust valve is not performed in a normal manner in at least one cylinder.

主权项

1. A control apparatus for an internal combustion engine including a valve stop mechanism, the control apparatus comprising:
an exhaust valve stop mechanism to change an operation state of an exhaust valve between a valve operating state and a valve closed and stopped state, the exhaust valve being provided in all cylinders of an internal combustion engine including at least one cylinder; an intake valve stop mechanism to change an operation state of an intake valve between a valve operating state and a valve closed and stopped state, the intake valve being provided in all the cylinders; an intake valve abnormality determination circuit which determines a presence or absence of an abnormality of a stopping operation of the intake valve by the intake valve stop mechanism; an air fuel ratio sensor which detects an air fuel ratio of gas discharged from each cylinder; a discrimination circuit which discriminates a presence or absence of a change to a rich side of an air fuel ratio of the gas detected by the air fuel ratio sensor while fuel supply is stopped for all the cylinders associated with a valve stop request for the exhaust valves and the intake valves of all the cylinders; and an exhaust valve abnormality determination circuit which determines that a stopping operation of the exhaust valve is not performed in a normal manner in at least one cylinder when the discrimination circuit discriminates that there is the change to the rich side of the air fuel ratio of the gas, in a case where it is determined that no abnormality has occurred in the stopping operation of the intake valve.