Patent ID: 7023682
Filing Date: 2006-04-04
Classification: F01L,F02D,H01F,H01H

Abstract:
1. A method for solenoid control comprising the following steps: providing a freewheel circuit that includes a solenoid connected to a system power supply via a resistive shunt and a freewheel diode in parallel with the solenoid, the resistive shunt being included in a current-measuring circuit that measures current through the solenoid; providing a current-control circuit comprising a differencing component, a power transistor and a switch device; supplying a voltage pulse to the freewheel circuit by means of said power supply to reach a predetermined current level in said solenoid, and thereafter: providing a voltage-control circuit comprising a second differencing component and having a structure similar to that of the current-control circuit; connecting an input of the second differencing component to an output of the current control circuit; applying into the freewheel circuit by means of the voltage-control circuit a control voltage of any value between 0 and a maximum supply voltage, thereby controlling the rate at which the current within the freewheel circuit decreases.