Abstract: A "returnless" fuel system for a motor vehicle is disclosed. A "series-pass" fuel regulator in the system includes an internal fluid passage containing a fluted pin and having a valve seat at one end. A valve ball bears against one end of the fluted pin and is biased toward the valve seat by a valve spring. The other end of the fluted pin bears against a diaphragm assembly. A main spring resists the movement the diaphragm assembly in the direction away from the fluted pin. The internal fluid passage in the regulator communicates with a chamber defined by the diaphragm assembly, the chamber further communicating with the outlet of the regulator. The inlet of the regulator communicates with the internal fluid passage when the valve ball is not seated against the valve seat and does not so communicate when the valve ball is seated against the valve seat.

Abstract: In one embodiment of the present invention, a "returnless" fuel delivery system for a motor vehicle includes a fuel pressure regulator located in the fuel tank and a fuel pressure damper located at the fuel rail on the vehicle's engine. The fuel return line from the fuel rail to the fuel tank, a conventional feature in fuel delivery systems, is eliminated. Fuel delivery systems according to the present invention can provide very precise fuel delivery at a highly competitive system cost.

Abstract: In one embodiment of the present invention, a "returnless" fuel system for a motor vehicle is disclosed. A "series-pass" fuel pressure regulator in the system provides fuel of a regulated pressure to a fuel rail comprising at least one fuel injector. A "bypass" fuel pressure regulator provides fuel with a regulated pressure to the series pass regulator. An in-line fuel filter is located downstream from the bypass regulator, such that only the fuel which reaches the series-pass regulator is filtered. A check valve is located downstream from the bypass regulator as well, to prevent fuel pressure bleed-down through the fuel pump and the bypass regulator. A pressure relief valve is coupled to allow fuel with a pressure above a predetermined value to flow around the check valve.