In-tank fuel pump and reservoir

Abstract

An engine fuel delivery system and method, and for use therein, an in-tank fuel pump and reservoir canister module assembly having a primary fuel filter mounted in a base subassembly adjacent the bottom of the tank and defining a filter chamber in the base having an outlet connected to the inlet of an electric fuel pump received directly in the tank exteriorly alongside of an upright open top reserve fuel canister. The pump outlet is connected to a bypass pressure regulator which discharges fuel in excess of engine demand into the canister. The canister has a bottom outlet mounted on the base subassembly and closed by a flow controlling valve and/or by a restricted orifice communicating the canister outlet with the filter chamber for returning bypassed reserve fuel from the canister reservoir to the pump inlet, either continuously and/or when a low level supply of fuel in the tank to the primary filter is interrupted, such as during cornering or going up or down a steep hill or incline. The valve is formed integrally on or mounted in contact with a secondary filter diaphragm base mounted between the canister outlet and filter chamber and also communicating with the tank. The valve opens with canister outflow downwardly against the bias of a coil spring in response to pump suction acting on a capillary seal formed on the diaphragm filter material to thereby allow reserve fuel to wash over and flow through it into the filter chamber. At system shut-down a filter backwash flow can occur from the canister reservoir.