Solenoid valve drive device

A solenoid valve drive device wherein a hysteresis set value or a hysteresis time is set based on a first difference value between an extreme value of a hysteresis value of a solenoid valve current in a peak hold section of the solenoid valve current and a hysteresis set value, the solenoid valve drive device comprising:

• a controller configured to:
• output an opening/closing command to a first switching element for turning on/off a drive current supplied to the solenoid valve,
• generate a hysteresis of the drive current by repeatedly turning on/off the first switching element in a first peak hold period after a current value of the drive current reaches a first current level, and
• (i) set extreme values of the hysteresis such that the hysteresis of the drive current falls within a predetermined range from the first current level, or (ii) set a time interval between extreme values of the hysteresis such that the hysteresis of the drive current falls within a predetermined range from the first current level;
• and
• a storage device configured to store set values of the extreme values of the hysteresis and a set value of the time interval between the extreme values of the hysteresis,
• wherein the controller is further configured to:
• calculate a first gradient of the hysteresis of the drive current using the extreme values of the hysteresis of the drive current and the time interval between the extreme values and calculate a second gradient of the hysteresis using the set values of the extreme values of the hysteresis and the set value of the time interval between the extreme values of the hysteresis, and
• set the extreme values of the hysteresis or set the time interval between the extreme values of the hysteresis so that a second difference value between the first gradient and the second gradient falls within a predetermined gradient threshold in a case where the second difference value is not within the predetermined gradient threshold.