Fuel pressure regulators have been disposed in various portions of vehicle fuel delivery systems to regulate the pressure of fuel delivered to an operating engine. In return type fuel systems, a fuel pressure regulator is typically disposed downstream of the engine fuel injectors and often on the engine fuel rail and fuel delivered in excess of the engine's fuel demand is returned by the fuel pressure regulator to the fuel tank through a return fuel line. In "return less" or no return type fuel systems, a fuel pressure regulator is disposed upstream of the engine and usually within the fuel tank immediately downstream of the fuel pump to bypass excess fuel delivered from the fuel pump into the fuel tank.
Fuel filters may be disposed downstream of the fuel pump as well to remove contaminants from the fuel delivered to the engine. Generally, fuel flow through the filter results in a pressure loss the magnitude of which increases as the fuel filter becomes increasingly clogged during use. Thus, it is preferable to regulate the pressure of the fuel downstream of any in-line fuel filter to remove the affects of the fuel filter on the pressure of fuel supplied to the engine.
One fuel system, as disclosed in U.S. Pat. No. 5,520,156, disposes an annular fuel filter in a depending skirt of a body attached to the fuel tank such that the fuel filter is immediately downstream of the fuel pump and the fuel delivered from the fuel pump flows through the fuel filter before being discharged from the fuel tank to an engine through a fuel line. In this fuel system, a fuel line connector and filter housing cap is removably received in the body and releasably retained by a ring threadably received on the body.
U.S. Pat. No. 5,433,241 discloses a module mounted on a fuel tank with an outer body receiving a fuel pressure regulator downstream of a fuel pump in the fuel tank. An inner body having an outlet through which fuel flows to a fuel line for delivery to the engine is disposed within the outer body to enclose a fuel filter therein. The inner body is press fit into the outer body with an O-ring between them to provide a seal.
Despite disposing one or more O-rings between the various members of these multiple piece assemblies, fuel vapors permeate the seals and escape from the fuel tank through the assemblies. The leaking hydrocarbon fuel vapors are hazardous to the environment and unacceptable under increasingly strict governmental regulations. Further, the multiple piece assemblies have a reduced strength and are subject to leaking liquid fuel as well as fuel vapors upon impact, such a during a vehicle accident.