| 摘要 |
PROBLEM TO BE SOLVED: To provide a valve control device capable of performing good valve closing operation and reducing motor driving circuit loss during PWM control. SOLUTION: A returning torque which moves a control valve in either of a valve opening direction or a valve closing direction is applied to an EGR valve. The valve control device comprises a valve driving motor 13 which applies a motor torque counteracting a returning torque to an exhaust gas circulation valve, and a motor driving circuit 12 which controls driving of a valve driving motor by PWM control to control opening and closing of the EGR valve in proportion to torque balance of the returning torque and the motor torque. Furthermore, the motor driving circuit has PWM switch elements 41 and 43 that controls the valve driving motor under PWM control, and non-PWM switch elements 42a and 44a which turns ON to bring a motor winding of the valve driving motor into a short-circuit state when PWM control elements are OFF. COPYRIGHT: (C)2005,JPO&NCIPI
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