FIELD: engine building.
SUBSTANCE: control device for the variable compression ratio internal combustion engine is provided with a variable compression ratio mechanism for varying the compression ratio of the engine in accordance with with the angular position of the control shaft and the compression ratio unit, which determines the actual compression ratio. In a predetermined state (S11) of the engine operation, such as immediately after starting the engine, the initial position learning operation for the compression ratio determination unit is performed (S12) with the control shaft mechanically locked in a predetermined initial position. During engine operation, even when the actual compression ratio is lost due to a communication error or the like (S13) or even when the difference between the actual compression ratio and the target compression ratio becomes greater than the allowable deviation due to some faults (S14), initial position learning operation is immediately executed (S15), thereby allowing a quick return to a state where normal control of the compression ratio can be performed.
EFFECT: ability to quickly return to a state where normal control of the compression ratio can be performed.
7 cl, 3 dwg
