| 摘要 |
PURPOSE: To enhance the valve opening detection accuracy and operation failure judgement accuracy of a flow rate control valve. CONSTITUTION: A step motor 43 is employed as a drive source for an EGR valve 42, and the rotary motion of its rotor 46 is transformed into a vertical motion of a motor shaft 49 via a female screw member 48, so that a valve body 53 is thereby moved up and down. Besides, a rotation detecting magnetic section 62 where each N pole and each S pole are alternately magnetized at a definite pitch, is formed at the upper end section of the rotor 46, and one or plural holes IC 61 are disposed above the rotation detecting magnetic section 62. The output pulse of the aforesaid holes IC 61 is counted so as to allow the rotary momentum of the rotor 46 to be detected, the detected rotary momentum is compared with a target momentum, it is then judged whether or not a deviation between both of them is in a range of allowable errors, and when the deviation is out of an allowable error, the operation of the EGR valve is judged as faulty. |
