In-tank fuel pump and reservoir

摘要

An in-tank fuel pump and reservoir canister module having a fuel filter mounted in the module base adjacent the bottom of the tank and defining a filter chamber having an outlet connected to the inlet of an electric fuel pump received directly in the tank exteriorly alongside of an upright overflow-type reserve fuel canister. A canister bottom outlet is closed by a flow controlling valve and/or by an always-open restricted orifice communicating with the filter chamber for returning engine bypassed reserve fuel from the canister reservoir to the pump inlet, either continuously and/or only when a low level supply of fuel in the tank to the filter is interrupted. The valve is operated by a diaphragm portion of the filter, base-mounted between the canister outlet and filter chamber and also communicating directly with the tank, the valve opening against the bias of a coil spring in response to pump suction acting on a capillary seal formed on the diaphragm filter to thereby allow reserve fuel to flow into the filter chamber. At system shut-down a filter backwash flow can occur from the canister reservoir. The pump rotary vane impeller chamber has an internal vapor purging passageway communicating at its outlet directly with the interior of the tank so as not to be subjected to any anti-purging gravity pressure head differential existing between the fuel level in the canister reservoir versus that of the main body of fuel in the tank.