Control device for internal combustion engine

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, and an exhaust-valve control apparatus for controlling at least close timing of an exhaust 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;
• exhaust-valve control means for performing close timing control which causes the exhaust-valve control apparatus to control the close timing of the exhaust valve such that the close timing of the exhaust valve coincides with a close 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 and a failure of the exhaust-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 and control of the close timing of the exhaust valve by the exhaust-valve control apparatus, wherein
• the exhaust-valve control means is configured such that, when the failure detection means has determined that the intake-valve control apparatus has a failure, the exhaust-valve control means performs, in place of the close timing control, combustion-percentage-increase-amount control which causes the exhaust-valve control apparatus to control the close timing of the exhaust valve such that the combustion percentage increase amount coincides with an increase amount target value;
• and
• the intake-valve control means is configured such that, when the failure detection means has determined that the exhaust-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 the increase amount target value.

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:

• 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;
• intake-valve control means for performing 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 becomes equal to an increase amount target value;
• and
• failure detection means for detecting a failure of the engine 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 failure detection means is configured to determine that the engine control apparatus has a failure when the degree of a deviation of the combustion percentage increase amount from the increase amount target value is greater than a predetermined degree during the combustion-percentage-increase-amount control.

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:

• 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;
• intake-valve control means for performing 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 becomes equal to an increase amount target value;
• and
• failure detection means for detecting a failure of the engine 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 failure detection means is configured to detect a failure of the engine control apparatus by making use of a change amount between the combustion percentage increase amount before the increase amount target value is changed by a predetermined amount during the combustion-percentage-increase-amount control and that after the increase amount target value has been changed by the predetermined amount during the combustion-percentage-increase-amount control.