To minimize reduction of engine output associated with knocking avoiding control and securely avoid the knocking.
An internal combustion engine equipped with a variable compression ratio mechanism capable of variable-controlling compression ratio is capable of reducing the compression ratio or lagging ignition time for the knocking avoiding control when a knock sensor detects knocking. In a relation of engine rotation speed Ne to loading Tp, the compression ratio reduction is carried out with priority on the lower speed side than a predetermined rotation speed NCR, and when the compression ratio reaches the limit, the ignition time is lagged. Lagging the ignition time is carried out with priority on the higher speed side than the NCR, and when the ignition time reaches the limit, the compression ratio is reduced. The output reduction is minimized as the influence of the compression ratio and the ignition time depends on operation conditions such as the rotation speed. The knocking can be securely avoided as for delay of changing the compression ratio in the high speed range.
HASEGAWA KAZUYA
TAKEMURA SHINICHI
Hiromichi Kobayashi
Tomioka Kiyoshi