1. Field of the Invention
The present invention relates to the field of fuel systems that include a fuel pump, a jet pump and a fuel filter.
2. Discussion of the Background
To date, the fuel delivery modules (FDM) require a substantial reservoir capacity to provide enough reserve fuel for low fuel considerations.
It is namely so that in certain circumstances, for example, when the volume of fuel contained in the fuel tank of an automotive vehicle falls below a certain minimum level and this vehicle travels through a prolonged curve, uphill or downhill, or if it is otherwise subjected to sudden and pronounced changes in speed, direction, etc., the fuel could be displaced to one side of the tank to such an extent that the inlet end of the dip tube, which forms part of the fuel-intake tubing, is at least temporarily no longer submerged in the fuel. Under such conditions, the dip tube sucks out air instead of fuel, thereby producing an interruption in the feed fuel flow that impedes the proper operation of the internal-combustion engine.
In order to avoid such problems, most fuel tanks include a reservoir i.e. a subtank intended to trap fuel and act as a reserve.
The use of a jet pump to fill a fuel reservoir within a fuel tank is a common technology. Typically, there is a separate pressurized fuel line from the outlet of the fuel pump or positive pressure from a connection to the pumping element or the return fuel from a fuel pressure regulator which connects to and supplies a jet pump which fills the reservoir to provide a reserve fuel supply for the fuel pump for low fuel conditions such as:                Hard acceleration/deceleration        Extended turns like a “clover leaf” on a highway access or egress.        Ascending or descending grades, (i.e. Sandia Pass in New Mexico)        
This Fuel line is in addition to the supply line to the engine and requires additional clamps and fittings to complete the circuit. Packaging the jet pump components presents complications in terms of locating the features without adding complexity to the reservoir and/or fuel pressure supply line. These additional components also add to the potential failure modes that must be considered and addressed with corrective actions in the design of the fuel delivery module.
Additionally, static electricity can build up within the pump, filter media and flow path to the point where the potential is high enough to cause an electrical discharge to the nearest ground point. This can cause electrical noise or, in the worst case, a thermal event inside the fuel tank. To solve that problem, a wire is often used to connect the negative (ground) terminal of the pump or the negative ground terminal of the fuel level sender and the conductive plastic filter housing. Any static charge built up in the filter housing will be conducted to this terminal.
A direct contact between pump and filter media could eliminate such a problem and the need for a ground wire and its associated failure modes. A direct contact between pump and filter has been proposed in U.S. Pat. No. 5,642,718, which does not address however the problems of the jet pump location/connection.
USPTO Backgrounds
USPTO Backgrounds