Patent ID: 8596233

Claim:
A spark ignition type internal combustion engine, comprising: a variable compression ratio mechanism able to change a mechanical compression ratio, a variable valve timing mechanism able to control a closing timing of an intake valve, a throttle valve arranged in an engine intake passage for controlling an intake air amount, and an electronic control unit having control logic which, when executed: retards the closing timing of the intake valve in a direction away from an intake bottom dead center as an engine load becomes lower from an engine high load to an engine low load, maintains the mechanical compression ratio at a maximum mechanical compression ratio in a load region where the engine load is lower than a predetermined first load, decreases the mechanical compression ratio as the engine load becomes higher so that an actual compression ratio becomes constant in a load region where the engine load is higher than the predetermined first load, holds the throttle valve in a fully open state in a load region where the engine load is higher than a predetermined second load, which is lower than the predetermined first load, decreases an opening degree of the throttle valve as the engine load becomes lower in a load region where the engine load is lower than the predetermined second load, and retards the closing timing of the intake valve in a direction away from the intake bottom dead center as the engine load becomes lower in the load region where the engine load is lower than the predetermined second load, and, in a load region where the mechanical compression ratio is maintained at the maximum mechanical compression ratio, the actual compression ratio is lowered as the engine load falls.