Patent ID: 6169335
Filing Date: 2001-01-02
Classification: F16H,F16K

Abstract:
A process for current control of an inductive load of an electrohydraulic pressure regulator in an automatic transmission of a motor vehicle, the process comprising the steps of: connecting a precision resistor (5) in series to the inductive load and electrically coupling the A/D converter (7) to the precision resistor (5);periodically measuring a voltage drop experienced across the precision resistor (5) and supplying the measured voltage drop to the A/D converter (7) where the measured voltage drop is converted to a current actual value (iact(t)); summing the current actual value (iact(t)), outputted by the A/D converter (7), with a supplied current reference value (iref(t)) to generate a combined error signal, and inputting the error signal to a clock controlled regulator (2); generating from the inputted error signal, via the clock controlled regulator (2), a regulating output signal (PWMregulator) for controlling a flow of current through the inductive load; synchronizing a time when the voltage across the precision resistor (5) is periodically measured by delaying an inquiry cycle of the AND converter (7) by a presettable time (dt) related to a cycle of the output signal (PWMregulator); and generating a pilot control second signal (S2), in a case of a substantial change in the current reference value (iref(t)), and combining the pilot control second signal (S2) together with the output signal (PWMregulator), generated by the clock controlled regulator (2), for controlling a flow of current through the inductive load.