No-return loop fuel system

Abstract

A no-return loop fuel injection system supplies fuel from a fuel pump to an injector fuel rail, through a fuel line. A biased closed pressure control valve communicates with the fuel line and has a valve head preferably of a diaphragm type carrying a fuel side having first and second areas which are segregated and defined by a valve seat when the pressure control valve is closed. An opposite second side of the pressure control valve is exposed to a reference pressure and a closure biasing force. The pressure control valve opens when a hydraulic opening force induced by a fuel pressure exerted upon the first area, plus a fuel pressure exerted upon the second area, is greater than the net reference pressure and closure biasing forces. Preferably, the first area is smaller than the second area, thus manipulating the effects of the fuel pressures exerted upon the first and second areas with respect to opening the valve. When the pressure control valve is open, the system operating pressure exposed to both the first and second areas is sufficient to produce the hydraulic force necessary to keep the valve open. Preferably, the pressure control valve is part of a pressure valve assembly of a fuel pump module located inside a fuel tank. The pressure valve assembly preferably has a flow check valve orientated in a parallel flow configuration to the pressure control valve when the fuel pump is of a variable speed type, or, for systems utilizing constant speed pumps the check valve is replaced with a flow bypass orifice.