Patent ID: 8681468

Claim:
A method of controlling a solenoid valve comprises: initiating engagement of the solenoid valve by applying to the solenoid valve either a pull-in voltage or a pull-in current; during the applying, maintaining either the pull-in voltage or the pull-in current and monitoring at least one of average voltage across the solenoid valve or current through the solenoid valve; from the monitoring, determining completion of engagement of the solenoid valve; and after the determining, maintaining the pull-in voltage or the pull-in current during a predetermined time lag after the determining completion of the engagement, and then reducing either the pull-in voltage maintained during the applying to a hold voltage, or the pull-in current maintained during the applying to a hold current, wherein the reducing maintains the engagement of the solenoid valve; wherein the monitoring includes monitoring both the average voltage across the solenoid valve and the current through the solenoid valve.