Patent ID: 7434399

Claim:
A supercharging pressure controller for an internal combustion engine, said controller comprising: a turbocharger that uses emission energy of exhaust gas flowing out of cylinders of an engine to rotate a turbine and to supercharge intake air suctioned into the cylinders of the engine; a motor that drives a compressor or a rotational shaft of the turbocharger; a supercharging pressure sensor for sensing supercharging pressure; and a motor controller means for controlling drive torque of the motor to substantially conform the actual supercharging pressure sensed by the supercharging pressure sensor to target supercharging pressure, wherein the motor controller means starts reducing the drive torque of the motor at a predetermined gradient based on actual emission energy applied to the turbine when the actual supercharging pressure is within a predetermined value from the target supercharging pressure and wherein the actual supercharging pressure is lower than the target supercharging pressure before the motor controller starts reducing the drive torque of the motor.