Patent ID: 6889121

Claim:
A computer implemented method for deriving a drive voltage waveform for a solenoid operated valve having a valve coil comprising the steps of: a) determining an initial estimate of electromagnetic parameters and a valve closure point, the electromagnetic parameters including a first L/R ratio corresponding to the pull-in time of the valve coil, a valve back emf, a second L/R ratio corresponding to the valve pull-hold time, and a hold resistance; b) deriving a drive voltage waveform based in part on the electromagnetic parameters and the valve closure point; c) obtaining a coil current feedback; d) determining the electromagnetic parameters and the valve closure point from the coil current feedback, thereby creating a revised estimate of the electromagnetic parameters and the closure point; e) updating the initial estimate with the revised estimate of the electromagnetic parameters and the valve closure point; and f) deriving a new voltage waveform based in part on the revised estimate of the electromagnetic parameters and the valve closure point.