Internal combustion engine and control device thereof

A control device for controlling an internal combustion engine that includes:

• (i) a supercharger including a compressor arranged in an intake passage of the internal combustion engine and supercharging intake air;
• (ii) a throttle valve arranged in the intake passage on a downstream side from the compressor and adjusting an intake air amount;
• and (iii) an actuator configured to control a supercharging pressure by adjusting a driving force of the compressor, the control device comprising:
• reserve control executing means for executing supercharging pressure reserve control in which, when there is (1) a request for switching of combustion from a first combustion at an air/fuel ratio at a stoichiometric air/fuel ratio or less to a lean combustion at an air/fuel ratio larger than the stoichiometric air/fuel ratio and (2) also there is a request for raising the supercharging pressure after the switching of combustion to a pressure higher than the supercharging pressure before the switching of combustion, the supercharging pressure is raised while a requested intake air amount required for realizing a requested torque of the internal combustion engine in the first combustion is maintained, by using the throttle valve and the actuator;
• and
• combustion switching executing means for executing the switching of combustion after the supercharging pressure reserve control is finished,
• wherein the supercharging pressure reserve control is finished when an actual supercharging pressure reaches a lower one of the requested supercharging pressure and a realizable supercharging pressure,
• the requested supercharging pressure is a supercharging pressure required for realizing the requested torque while the supercharging pressure reserve control is being executed in the lean combustion, and
• the realizable supercharging pressure is a maximum supercharging pressure realizable by adjustment of the actuator under an actual intake air amount while the supercharging pressure reserve control is being executed.