CONTROL DEVICE FOR VARIABLE COMPRESSION RATIO INTERNAL COMBUSTION ENGINE

摘要

PROBLEM TO BE SOLVED: To solve problems that when rapid increase and reduction in an accelerator opening are repeated in a short period, an actual compression ratio can not follow a target compression ratio to enlarge a deviation Δε therebetween, which induces possibility of knocking or pre-ignition.

SOLUTION: A control device includes a variable compression ratio device that can vary an engine compression ratio, and sets a target compression ratio with respect to engine operation conditions, and variably controls the engine compression ratio to the target compression ratio. The control device adds up deviations Δε of an actual compression ratio from the target compression ratio in a prescribed period to obtain an integrated value S of compression ratio deviations. When the integrated value S exceeds a prescribed threshold, the control device determines that rapid increase and decrease in the target compression ratio (intake air amount) is repeated, and corrects the target compression ratio toward a lower side and suppresses unnecessary increase in the actual compression ratio to avoid occurrence of knocking or pre-ignition.

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