CONTROL APPARATUS FOR INTERNAL COMBUSTION ENGINE

According to first quantity of state control, a rich spike is executed while actuating a waste gate valve (46) so as to decrease turbocharging pressure, and after completion of the rich spike, the waste gate valve (46) is actuated to raise the turbocharging pressure again, the combustion air-fuel ratio is adjusted to the theoretical air-fuel ratio while suppressing an air amount by a throttle (40) so as not to vary shaft torque until the turbocharging pressure is restored, and upon the turbocharging pressure being restored the air amount is increased by the throttle and the combustion air-fuel ratio is returned to a lean air-fuel ratio. According to second quantity of state control, a rich spike is executed while actuating the waste gate valve (46) so as to maintain the turbocharging pressure, and after completion of the rich spike, the air amount is increased by the throttle (40) and the combustion air-fuel ratio is returned to a lean air-fuel ratio.