The invention is directed to an improved position sensor for a latching solenoid (15). In the preferred embodiment, the solenoid has a permanent magnet (16), a coil (18) adapted to be selectively energized by either a positive or negative current, a first pole-piece (19) and a second pole-piece (20),...http://www.google.com.au/patents/US6351199?utm_source=gb-gplus-sharePatent US6351199 - Position sensor for latching solenoid valve
