Control Device and Control Method for Internal Combustion Engine

摘要

An engine includes a variable valve mechanism capable of holding a valve timing of an intake valve in an intermediate phase when the engine is started. An ECU calculates a degree of deposit adhesion in a combustion chamber, and calculates a deposit correction amount that is a retard correction amount for an ignition timing set in accordance with the calculated degree of the deposit adhesion. The ECU calculates a first correction amount that is a first adaptive value for the retard correction amount for the ignition timing in a reference phase of the valve timing and a second correction amount that is a second adaptive value for the retard correction amount for the ignition timing in an adaptation phase of the valve timing. The deposit correction amount is set based on the first correction amount and the second correction amount.

主权项

1. A control device for an internal combustion engine, the internal combustion engine including an intake valve, a combustion chamber, and a variable valve mechanism, the variable valve mechanism being configured to change a valve timing of the intake valve, and the variable valve mechanism being configured to hold the valve timing in an intermediate phase when the internal combustion engine is started, the intermediate phase being a phase set in a middle between a most retarded phase and a most advanced phase of the valve timing of the intake valve, the control device comprising
an electronic control unit configured to:
calculate a degree of deposit adhesion in the combustion chamber;calculate a deposit correction amount, the deposit correction amount being a retard correction amount for an ignition timing set in accordance with the degree of the deposit adhesion;calculate, as a reference correction amount, a first adaptive value for the retard correction amount for the ignition timing with which occurrence of knocking is suppressed when the amount of the deposit adhesion is equal to or more than a predetermined amount and a phase of a present valve timing is a reference phase, the reference phase being a phase of the valve timing at which an internal exhaust gas recirculation amount in the combustion chamber is minimized;calculate a first correction amount by correcting the reference correction amount in accordance with the degree of the deposit adhesion;calculate, as an adaptive correction amount, a second adaptive value for the retard correction amount for the ignition timing with which the occurrence of the knocking is suppressed when the amount of the deposit adhesion is equal to or more than the predetermined amount and the phase of the present valve timing is an adaptation phase, the adaptation phase being a phase of the valve timing optimal in accordance with an engine operation state;calculate a relative correction amount by subtracting the reference correction amount from the adaptive correction amount;calculate a correction ratio indicating a degree of an effect of the present valve timing on an ignition timing correction in accordance with the degree of the deposit adhesion;calculate a second correction amount by correcting the relative correction amount in accordance with the degree of the deposit adhesion and the correction ratio; andset a sum of the first correction amount and the second correction amount as the deposit correction amount.