Patent ID: 8014935

Claim:
A control apparatus for an internal combustion engine including an intake-valve control apparatus which controls at least open timing of an intake valve of the internal combustion engine, the engine control apparatus comprising: intake-valve control means for performing open timing control which causes the intake-valve control apparatus to control the open timing of the intake valve such that the open timing of the intake valve coincides with an open timing target value; combustion percentage acquisition means for acquiring a change in combustion percentage with crank angle, the combustion percentage being the ratio of an amount of combusted fuel, which increases continuously during an expansion stroke, to a total amount of fuel taken into a combustion chamber of the internal combustion engine in an intake stroke; and failure detection means for detecting a failure of the intake-valve control apparatus by making use of an increase amount of the combustion percentage within a predetermined crank angle range during the expansion stroke, the increase amount changing as a result of control of the open timing of the intake valve by the intake-valve control apparatus, wherein the intake valve control means is configured such that, when the failure detection means has determined that the intake-valve control apparatus has a failure, the intake-valve control means performs, in place of the open timing control, combustion-percentage-increase-amount control which causes the intake-valve control apparatus to control the open timing of the intake valve such that the combustion percentage increase amount coincides with an increase amount target value.