Patent ID: 6922995

Claim:
A control method for a supercharging device for supercharging intake air in an intake passage of an internal combustion engine based on a required intake air flow rate of the engine, the device comprising a positive-displacement supercharger disposed in the intake passage, an electric motor driving the supercharger in response to a supplied electric power, the electric motor functioning as a generator when a rotational energy is input from the supercharger, a bypass passage bypassing the supercharger and connecting an upstream portion and a downstream portion of the intake passage, and a bypass valve which opens and closes the bypass passage, the method comprising: determining a discharge flow rate of the supercharger; regulating an opening of the bypass valve based on the discharge flow rate of the supercharger and the required intake air flow rate of the engine; driving the supercharger by supplying electric power to the electric motor to supercharge intake air in the intake passage when the required intake air flow rate of the engine is greater than a predetermined threshold value; and causing the electric motor/generator to generate electric power by a rotational energy input from the supercharger which rotates according to an air flow in the intake passage when the required intake air flow rate of the engine is not greater than the threshold value.