SUPERCHARGING DEVICE FOR ENGINE

PROBLEM TO BE SOLVED: To provide a supercharging device for an engine capable of eliminating or restraining surging by surely and quickly predicting or detecting the occurrence of the surging. SOLUTION: This engine 1 has a motor-driven supercharger 6. A rotating speed of a motor 6b is detected by a motor rotating speed sensor 21. Vibration of the rotating speed of the motor 6b is detected by band-pass filter processing by a control unit 20, and a determination is also made on whether or not the rotating speed of the motor 6b vibrates. When determined that the rotating speed of the motor 6b vibrates, a determination is made that the surging is caused in the motor-driven supercharger 6. When the surging is caused in the motor-driven supercharger 6, a bypass valve 11 is properly opened, and a part of pressurized suction air is recirculated to an upstream side common intake passage 3 via a bypass intake passage 10, and the surging is eliminated or restrained. COPYRIGHT: (C)2007,JPO&INPIT