US 7,610,901 B2
	Method for detecting the opening of a passive pressure control valve
Martin Bucher, Bermatingen (Germany); Armin Dölker, Friedrichshafen (Germany); Volker Wachter, Mengen (Germany); and Uwe Kosiedowski, Owingen (Germany)
Assigned to MTU Friedrichshafen, Friedrichshafen (Germany)
Filed on Oct. 19, 2007, as Appl. No. 11/975,585.
Claims priority of application No. 10 2006 049 266 (DE), filed on Oct. 19, 2006.
Prior Publication US 2008/0092852 A1, Apr. 24, 2008
This patent is subject to a terminal disclaimer.
Int. Cl. F02M 69/54 (2006.01); F02M 69/52 (2006.01)

U.S. Cl. 123—457

8 Claims

1. A method for detecting opening of a passive pressure control valve, which conducts fuel from a common rail system back to a fuel tank, comprising the steps of: automatically controlling rail pressure (pCR) by calculating a correcting variable for acting on a controlled system from a rail pressure control deviation (ep) via a pressure controller; detecting, starting from a steady-state rail pressure in normal operation, a load reduction when the rail pressure (pCR) exceeds a first limit (GW1); and detecting opening of a pressure control valve after the first limit (GW1) is exceeded if a steady-state operating state is subsequently detected again, and if a characteristic of a closed-loop control system deviates significantly from a reference value (REF).