GB2525414A - Fuel pump module for a fuel tank - Google Patents

Abstract

A fuel pump module 12, normally within a fuel tank 10, features a fuel pump 13, and jet inlet pump 40, which may feature a venturi arrangement. A portion 42 of fuel outlet from the fuel pump 13 is fed to the inlet pump 40 to power it, drawing fuel into the module 12. Control means 46, cuts the supply to the jet inlet pump 40 when a fuel level in the module 12 or surrounding fuel tank 10 exceeds a certain level, as measured and controlled by appropriate sensors and a control system 36. The cut off system may include a float and cut off valve arrangement (figs.2,3). As such under conditions of a full tank 10, or level of fuel in the tank 10 being such that the module 12 fills up naturally, such as via inlet 18, operation of the jet inlet pump 40 is not needed, and so it can be shut down.

Description

FUEL PUMP MODULE FORA FUEL TANK

TECHNICAL FIELD

The present invention generally relates to a fuel pump module for a liquid fuel tank of a combustion engine, in particular for an automotive vehicle.

BACKGROUND OF THE INVENTION

In transportation vehicles such as trucks, cars, planes and boats, the on-board fuel tank is generally shaped to maximize fuel storage capacity yet fit within often restricted areas dictated by the surrounding vehicle structure or chassis. The fuel tank may define one storage chamber, but may often be subdivided in two or more fuel storage chambers. Typically at least one fuel chamber is equipped with an electric motor fuel pump to supply the fuel demand to the engine in the vehicle.

The electric fuel pump is known to be integrated into an in-tank fuel pump module. A support structure of the module usually includes a flange mounted sealably to the fuel tank and a reservoir can is typically part of the module. The fuel pump is usually located in the reservoir can and draws fuel therefrom. The reservoir provides a reliable source of liquid fuel for the fuel pump even when the larger fuel chamber is relatively low of fuel and/or when the fuel within the supply chamber sloshes about due to movement of the vehicle or any other dynamics occurring relative to the vehicle.

A reservoir jet pump typically maintains adequate fuel levels in the reservoir can by routing a minority portion of pressurized fuel from the electric pump outlet and sending it through a venturi tube which in-turn aspirates a much greater amount of fuel from the fuel tank and into the reservoir. Typically the jet pump functions continuously regardless of reservoir fuel level and regardless of the fuel pressure at the pump outlet or pressure at the fuel rail. It is thus common for fuel in the reservoir can to overflow back into the fuel chamber.

The object of the present invention is to provide an improved fuel pump module.

SUMMARY OF THE INVENTION

The present invention derives from the observation that the operation of the jet pump is not required all the time. In particular, the jet pump does not appear to be necessary when the fuel reservoir is full, or when the fuel level in the fuel tank is above the top opening of the reservoir cup, which fills naturally by overflowing.

Accordingly, the present invention provides a fuel pump module for a fuel tank that comprises: a fuel reservoir to be placed in a liquid fuel tank; a fuel pump in said fuel reservoir, said fuel pump having an inlet to draw in fuel, and an outlet to discharge pressurized liquid fuel; and a jet pump for drawing fuel into said fuel reservoir, said jet pump being supplied with driving fuel from said fuel pump through a jet supply duct for driving its pumping effect.

It shall be appreciated that the present fuel pump module comprises flow control means associated with said jet pump or said jet supply duct and configured to stop the supply of driving fuel to said jet pump when the fuel level meets a predetermined fuel level. The predetermined fuel level of relevance may be set as a fuel level inside the fuel reservoir and/or inside the fuel tank.

By way of the flow control means it is possible to stop the flow of driving fuel (i.e. the portion of fuel from the fuel pump that allows operation of the jet pump) when the fuel level is equal or above a predetermined level, at or above which the jet pump is not considered necessary. The predetermined fuel level may be set so as to correspond to the upper edge of the reservoir or about this region.

Stopping the fuel feed to the jet pump allows using the full pumping capacity of the fuel pump for the supply of fuel to the engine fuel rail. In fact, cancelling the routing of a portion of pressurized fuel to the jet pump to serve as driving fuel will increase the flow, and hence pressure, to the engine fuel conduit. This will be detected by the ECU, which will in turn reduce the demand on the fuel pump. This will result in a decrease of the pump consumption and thus positively impact (decrease) the overall vehicle C02 emissions.

The flow control means may comprise a control valve that may be arranged in the jet supply duct, but preferably in the jet pump.

The flow control means comprise fuel level sensing means to monitor the fuel level, and the closure or opening of the flow control means may thus be triggered based on the detected level or status or configuration of the fuel level sensing means. In this connection, it may be noticed that fuel level sensing means may be of any appropriate type: fully mechanical systems can be employed, e.g. based on a float, but electro-mechanical level sensors can likewise be used.

The fuel level sensing means may be located inside and/or outside said fuel reservoir, e.g. in the fuel tank. For ease of realisation, the fuel level sensing means is preferably located inside the reservoir.

The control valve of the flow control means further comprises an actuating mechanism that cooperates with the fuel level sensing means.

The jet pump may generally comprise a body having an inlet section, a nozzle orifice and a Venturi tube. The jet pump is generally arranged inside the reservoir in the vicinity of an opening in the reservoir wall (e.g. bottom reservoir wall or nearby) to draw in fuel from the tank.

The control valve is preferably arranged upstream said of said nozzle orifice, e.g. in said inlet section.

The control valve advantageously comprises a flow passage having therein a valve seat that cooperates with a valve member, which is operated by the actuating mechanism.

In one embodiment, the actuating mechanism comprises a pivoting lever having a first branch, on one side of the pivot, acting, directly or indirectly, on the valve member, and a second branch, on the opposite side of the pivot, supporting a float extending in said reservoir. The lever and float are configured in such a way that the control valve is open when the fuel level in the reservoir is below said predetermined fuel level. This embodiment is of course of interest in that it is passive and does not require any battery power.

In alternative embodiments relying on electro-mechanical fuel level sensing means, using e.g. a float switch, capacitive device or other, the actuating mechanism comprises a motor for moving the valve member between its open and closed position depending on a fuel level signal generated by the fuel level sensing means.

As regards fuel level sensing in the fuel tank, one could exploit the signal generated by the conventional fuel level sensor, and operate the actuating means in order to close the control valve when the fuel level is above the predetermined fuel level.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, with reference to the accompanying drawings, in which: FIG. 1: is a principle drawing of the present fuel pump module mounted in a vehicle liquid fuel tank; FIGS. 2 and 3: are section views through an embodiment of a jet pump with integrated flow control valve, in open and closed positions, respectively; FIG. 4: is a detail view of the flow control valve of Figs. 2 and 3.

DETAILED DESCRIPTION OF A PREFERRED EMBODIMENT

Fig. 1 is a principle drawing illustrating the principle of the present invention, as applied to a liquid fuel tank 10 of an automotive vehicle with internal combustion engine.

The present fuel pump module is generally indicated 12 and is installed inside the fuel tank 10, which may be designed to contain liquid fuel 11 such as diesel or gasoline.

The fuel pump module 12 comprises a fuel pump 13 disposed in a fuel reservoir 14 that is formed by a generally cup-shaped reservoir (or "cup") having a top opening 15 and fixedly mounted within the fuel tank 10.

The top of the fuel tank 16 is provided with an opening 18 for inserting the fuel pump module 12 into the fuel tank 10. As it is known in the art, the fuel tank 10 substantially sealingly defines a fuel receiving space when the opening has been closed by a set plate 20.

The reservoir 14, which forms a "subtank" or "reserve cup," is disposed in proximity of the bottom plate 22 within the fuel tank 10. The reservoir may be fixed to the bottom plate, or rigidly connected to set plate by means of spacing studs. The reservoir cup 14 reserves a fuel, which flows into the cup 14 from within the fuel tank 10 and is drawn into fuel pump 13 arranged in the reservoir 14.

Fuel pump 13 typically includes an inlet 26 that draws in fuel from the reservoir 14 and at least one pressurized fuel outlet 28. The fuel pump 24 is typically electrically operated and may be of any standard design.

The inlet 26 can be covered by a filter (not shown). The fuel pump outlet 28 is routed to an engine fuel supply line 30 via an outlet duct 32 and a supply port 34 mounted in plate 20. The engine fuel supply line 30 delivers fuel to the engine's injection system 35 (e.g. a high-pressure common rail system). A pressure relief valve (not shown) may be integrated in outlet duct 32.

In modern engine designs, as shown in Fig.1, a pressure sensor 34 is arranged to sense the fuel pressure in fuel supply line 30. The signal 33 generated by the pressure sensor 34 is received in a control unit 36, generally the Engine Control Unit (ECU), which may then send a control signal 37 to the electronic unit 38 of the fuel pump module 12, in order to adapt the fuel pump operation so as to reach a desired pressure in the engine fuel supply line 30.

The control and operation of a fuel pump module 12 by an ECU in this regard is well known in the art and does not need to be further detailed herein.

Reference sign 40 symbolises a jet pump that is arranged in the vicinity of an opening 41 in the reservoir wall that may generally be located in the bottom reservoir wall or nearby. Classically, a jet pump is a device that is configured to create a pumping action to transfer fuel outside of the reservoir cup 14 into the jet pump 40, and thence into the reservoir cup 14, by using a fuel flow discharged from the fuel pump 24 as a driving source.

This is generally achieved by using the Venturi principle. Accordingly, line 42 in Fig.1 materialises the jet supply duct that supplies a flow of pressurized fuel from the fuel pump 24 to the jet pump 40, which comprises a nozzle 401 and a Venturi tube 402.

It may be noted that the connection of the jet supply duct 42 at the level of the fuel pump 24 may depend on the design. The fuel pump 24 may comprise an outlet 28' dedicated to the jet pump supply in addition to the main outlet 28 connected to the engine supply line 30. Alternatively, the fuel pump may have a single outlet, and the jet supply duct may branch off from the output line.

Reference sign 46 generally indicates flow control means adapted to stop the supply of fuel through the jet supply duct 42 when the fuel level meets a predetermined level. The idea here is to stop the flow through the jet supply duct when not needed, e.g. when the reservoir is full or when the fuel level in the fuel tank is high enough for the reservoir to be filled by simple overflow. Accordingly, the flow control means comprise an associated fuel level sensing means that will control the actuation of the flow control means so as to allow or hinder the flow of fuel from the pump l3to the jet pump 40. In the schematic drawing of Fig.1 the flow control means 46 are represented on the supply duct, which is a possibility. The flow control means 46 can be arranged at any position in the jet feed line, between the output of the fuel pump and the nozzle 401.

A variety of designs can be envisaged by those skilled in the art in order to implement the present invention.

An embodiment where the flow control means is integrated in a jet pump will now be described with reference to Figs. 2 to 4. This jet pump, indicated 100, can be used otherwise standard fuel pump module designs.

Having regard to Fig.1, jet pump 100 can be used in place of jet pump 40, i.e. over opening 41 (but the flow control means identified 46 in Fig. 1 would not be required, since they are integrated in the jet pump 100).

Fig. 2 illustrates ajet pump 100 comprising a body 102 having therein an inlet section 104 for connection to a jet supply duct (such as e.g. duct 42) connected at the other end to a fuel pump outlet (e.g. pump 13), a nozzle 106 and a Venturi tube 108 (also referred to as mixing tube).

The nozzle 106 is mounted inside a base portion 110 of the body 102, where it is connected to the inlet section 104 and has its nozzle orifice 112 inside an open chamber 114 and directed towards the Venturi tube 108.

Chamber 114 is open towards the Venturi tube 108 and downwardly, and the jet pump 100 is arranged in the reservoir cup l4so as to be above an orifice that opens in the fuel tank (such as orifice 41). Flow of fuel out of nozzle orifice 112 and through Venturi tube 108 causes a reduction in pressure in the region of chamber 114 relative to the pressure in the main fuel tank 10, which in turn causes fuel to be entrained from the tank into the jet pump 100 through Venturi tube 108 and then into the reservoir 14.

In the present variant, the flow control means take the form of a control valve 118 integrated inside the jet pump 100, in the inlet section 108 thereof, i.e. upstream of the nozzle 106. As it can be seen, both the control valve 118 and the nozzle 106 are designed as independent parts, the former being fitted though the bottom 110 in the inlet section, and the latter in a recess in bottom 110. Control valve 118 is tightly fitted in inlet section 104, against a shoulder 1041. Nozzle 106 is fixed in place by means of a pin 1061 inserted in a corresponding borehole 1101.

The internal construction of control valve 118 will be better understood from Fig.4. Control valve 118 comprises a body 120 sealingly mounted in the inlet section 108 with a fuel flow passage 122 therein, extending between an inlet port 124 and an outlet port 126. A sealing seat 128 is arranged in a valve chamber 130 in said passage 122, with which a valve member 132 cooperates to allow, or close, the flow of fuel through the control valve 118. An actuation mechanism 134 is provided to move the valve member between the closed position, in which it rests on the valve seat and hinders the flow of fuel through the jet pump and an open position, lifted off from the valve seat.

When the control valve 118 is open, driving fuel received from the pump enters the valve 118 via inlet port 124 and inlet passage 124a, flows to the valve chamber 130 and further to outlet passage 126a and outlet port 126, from which it flows into an inlet portion 136 of nozzle 106.

In the present variant, the valve actuation mechanism simply comprises an actuating lever 140 extending inside the reservoir cup and fixed to body 102. Lever 140 has an actuating branch 142 acting on the valve member 130 and a handling branch 144 that is provided at its end with a floater 146. The lever 140 pivots about an axis 148, which also serves as fixing point. On the valve side of lever 140, the actuation branch 142 has a curved extremity forming a cam portion that cooperates with a pin 149 in a wall of valve chamber 130. When the lever rotates clockwise about axis 148, pin 149 is pushed to the right, hence moving valve member 130 towards the valve seat 128.

As it will be understood, the float 146 will rise or fall with the fuel level inside the reservoir cup, and thus cause a corresponding pivoting movement of the lever 140. In the configuration shown in Fig.2, the fuel level in the reservoir is low, at least lower than the predefined level, whereby the valve member 132 is off the valve seat 128, allowing the flow of fuel through the control valve 118 and hence allowing operation of the jet pump 100. The jet pump 100 operates according to its nominal function, which is to fill the reservoir.

Starting from the configuration of Fig.2, as the jet pump 100 progressively fills up the reservoir, the float 146 will rise, causing the pivoting of lever 140 to progressively bring the valve member 132 against the valve seat 128 and to finally close the valve, as shown in Fig.3. The jet pump 100 is thus deactivated.

Preferably, the level sensing means are configured so that the valve is closed when the reservoir is full or nearly full.

In practice, the control valve will thus be closed as long as the fuel level in the fuel tank is above the reservoir cup. Also when the fuel level in the tank is low, the control valve will be closed a great amount of time since the pumping rate of the jet pump is much greater than the engine consumption. The closure of the fluid communication between the fuel pump and jet pump nozzle, when not needed, allows reducing the demand on the fuel pump, and results in an overall reduction vehicle emissions.

Claims (13)

1. CLAIMS1. A fuel pump module for a fuel tank, comprising: a fuel reservoir (14) to be placed in a liquid fuel tank (10); a fuel pump (13) in said fuel reservoir (14), said fuel pump (13) having an inlet (26) to draw in fuel, and an outlet (28) to discharge pressurized liquid fuel; a jet pump (40; 100) for drawing fuel into said fuel reservoir (14), said jet pump (40; 100) being supplied with fuel from said fuel pump (13) through a jet supply duct (42); characterized by flow control means (46; 118) associated with said jet pump (40; 100) or said jet supply duct (42) and configured to stop the supply of driving fuel to said jet pump (40; 100) when the fuel level meets a predetermined fuel level.
2. 2. The fuel pump module according to claim 1, wherein the flow control means comprise a control valve (118), preferably in said jet pump (100).
3. 3. The fuel pump module according to claim 1 or 2, wherein the flow control means comprise fuel level sensing means to monitor the fuel level in the fuel reservoir (14) and/or in the fuel tank (10) based on which the closure or opening of the flow control means is triggered.
4. 4. The fuel pump module according to claims 2 and 3, wherein said control valve (118) comprises an actuating mechanism that cooperates with the fuel level sensing means.
5. 5. The fuel pump module according to claim 3 or 4, wherein said fuel level sensing means is of the mechanical or electro-mechanical type.
6. 6. The fuel pump module according to any one of claims 2 to 5, wherein said jet pump comprises a body (102) comprising an inlet section (104), a nozzle orifice (112) and a Venturi tube (108), and wherein said control valve (118) is arranged upstream said of said nozzle orifice (112), preferably in said inlet section (104).
7. 7. The fuel pump module according to any one of claims 2 to 6, wherein said control valve comprises a flow passage (122) having therein a valve seat (128) that cooperates with a valve member (132), which is operated by said actuating mechanism.
8. 8. The fuel pump module according to any one of claims 2 to 7, wherein said fuel level sensing means are located inside and/or outside said fuel reservoir.
9. 9. The fuel pump module according to any one of claims 2 to 8, wherein said actuating mechanism comprises a pivoting lever (140) having a first branch, on one side of the pivot, acting, directly or indirectly, on said valve member, and a second branch, on the opposite side of the pivot, supporting a float that extending in said reservoir, the lever and float being configured in such a way that the control valve is open when the fuel level in said reservoir reaches or drops below said predetermined fuel level.
10. 10. The fuel pump module according to any one of claims 2 to 8, wherein said actuating mechanism comprises a motor for moving said valve member between its open and closed position depending on a fuel level signal generated by said fuel level sensing means.
11. 11. The fuel pump module according to any one of the preceding claims, wherein said predetermined fuel level substantially corresponds to a full reservoir.
12. 12. The fuel pump module according to claims 2 and 3, wherein said fuel sensing means comprise a fuel level sensor in said tank, which generates a signal representative of the fuel level in said fuel tank; and said actuation mechanism actuates said control valve based on said signal.
13. 13. A fuel tank having at least one chamber comprising therein a fuel pump module according to any one of the preceding claims.