CONTROL DEVICE OF ELECTRIC VARIABLE VALVE TIMING DEVICE

PROBLEM TO BE SOLVED: To prevent overheat of a motor and to prevent degradation of durability and malfunction due to overheat of the motor, in an electric variable valve timing device using the motor as a driving source. SOLUTION: When starting the engine, stop/rotation of the motor 26 is detected based on existence of an output pulse of an encoder built in the motor 26 and a current-carry control (a duty control) of the motor 26 is inhibited and the motor 26 is kept in a current-carry off state till rotation start of the motor 26 is detected and the current-carry control of the motor 26 is started after the rotation start of the motor 26 is detected. When stopping the engine, the stop/rotation of the motor 26 is detected by using a time interval of the pulse output from the encoder (or the motor rotation speed calculated from this), the current control of the motor 26 is permitted till rotation stop of the motor 26 is detected and current supply of the motor 26 is stopped by inhibiting the current-carry control of the motor 26 at the time point when the rotation stop of the motor 26 is detected. COPYRIGHT: (C)2009,JPO&INPIT