PURPOSE: To accurately operate a solenoid valve regardless of dispersion of the resistance value of a coil and influence of oil pressure, etc., by correcting the duty ratio of a specified pulse voltage electrified to the coil in response to detected values of a current value and a voltage value of the coil for driving the valve body of the solenoid valve.
CONSTITUTION: A solenoid valve (c) is opened/closed by moving a valve body (b) by electromagnetic force generated in accordance with electrification to a coil (a). In this case, a current value electrified to the coil (a) and the voltage value impressed to the coil (a) are detected by detection means d1, d2, respectively. On the other hand, the duty ratio of a specified pulse voltage electrified to the coil (a) is controlled by a duty control unit (e). The output of the duty control unit (g) is corrected by a correcting part (f) in response to the current value and the voltage value detected by the respective detection means d1, d2. Consequently, the solenoid valve (a) is accurately operated even if moving speed and timing of the valve body (b) are changed due to dispersion and variation of a resistance value, and influence of oil pressure, etc., in the coil (a).
TAZAWA MITSUGI
MORITA NORIO
NACHI FUJIKOSHI CORP
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