FUEL SUPPLY SYSTEMS

Abstract

A fuel supply system includes a fuel pump disposed within the fuel tank A cover can close an opening formed in an upper portion of the fuel tank. A receptacle is provided on the cover. A controller can control the operation of a motor of the fuel pump. The controller includes an earth terminal and noise-generating electrical elements. The receptacle has an electrically conductive wall surrounding at least the electrical elements of the controller. The electrically conductive wall is electrically connected to the earth terminal of the controller.

Description

This application claims priority to Japanese patent application serial number 2006-132267, the contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to fuel supply systems that have a controller for controlling a motor that is adapted to drive a fuel pump.

2. Description of the Related Art

A known fuel supply system is disclosed, for example, in Japanese Laid-Open Patent Publication No. 8-177668. As shown in FIG. 5, the known fuel supply system includes a cover 104 that is fixedly attached to the top wall of a fuel tank 101 in order to close an opening 102 formed in the top wall. The cover 104 is formed of resin and includes a tubular portion 105 extending into the inner space of the fuel tank 101. A pump case 106 is suspended from the lower end of the tubular portion 105. A fuel pump 107 is disposed within the pump case 106. A depressed portion 105h opened to the exterior of the fuel tank 101 is formed in the tubular portion 105. A controller 108 for controlling a motor of the fuel pump 107 is received within the depressed portion 105h.

The controller 108 actuates a switching element (not shown) based on a signal supplied from an ECU in order to generate a pulsed voltage that is supplied to the motor of the fuel pump, so that a mean voltage applied to the motor of the fuel pump 107 can be controlled. Hence, the output of the fuel pump 107 is adjusted so as to keep a constant fuel pressure within a delivery pipe 116, to which fuel injectors 115 are attached.

Because the controller 108 actuates the switching element in order to generate a pulsed voltage, noise may be produced during the actuation of the switching element. In addition, because the cover 104, in which the controller 108 is disposed, is formed of resin, the cover 104 does not serve to absorb or reduce noise. As a result, a complicated filtering circuit including choke coils and capacitors is needed, which results in increase in costs.

Thus, there is a need in the art for a fuel supply system that can effectively reduce potential noise that may be generated by a controller of a fuel pump motor.

SUMMARY OF THE INVENTION

One aspect according to the present invention includes fuel supply systems for supplying a fuel from a vehicle fuel tank. The system includes a fuel pump disposed within the fuel tank, a cover capable of closing an opening formed in an upper portion of the fuel tank, a receptacle disposed on the cover, and a controller capable of controlling the operation of a motor of the fuel pump. The controller includes an earth terminal and noise-generating electrical elements. The receptacle has an electrically conductive wall surrounding at least the electrical elements of the controller, which may produce noise. The electrically conductive wall is electrically connected to the earth terminal of the controller.

With this arrangement, the noise-generating electrical elements can be shielded from the outside of the receptacle. Therefore, it is possible to eliminate the influence of the noise on the other controllers, such as an engine control unit (ECU), of a vehicle. In addition, it is not necessary to use a large-scale filtration circuit.

The noise-generating electrical elements may include a resister, a capacitor, a coil and a switching element as well as conductors of an electric circuit board.

In one embodiment, the controller is operable to produce a pulsed voltage by the actuation of a switching element in order to control a mean voltage applied to the motor.

In another embodiment, the electrically conductive wall of the receptacle is formed of metal. Alternatively, the electrically conductive wall may be formed of resin containing electrically conductive material or may include a resin layer and an electrically conductive material layer.

In a further embodiment, the fuel supply system further includes a spring that can resiliently hold the connecting condition between the electrically conductive wall and the earth terminal of the controller. With this arrangement, the electrical connection between the electrically conductive wall and the earth terminal can be reliably maintained for a long time without causing accidental disconnection when an external force, such as vibrations, has been applied to the receptacle.

In a further embodiment, the receptacle at least partly extends into the inner space of the fuel tank, so that the fuel within the fuel tank can contact with the receptacle. With this arrangement, it is possible to cool the receptacle as well as the controller by the fuel.

Another aspect of the present invention includes fuel supply systems used in combination with a fuel tank. The fuel supply systems include a fuel pump including a motor, a controller for controlling the motor, and a receptacle that receives the controller and is mounted to the fuel tank. The receptacle includes a noise-shielding wall capable of shielding noise when the noise is generated by the controller. The noise-shielding wall may be an electrically conductive wall surrounding at least a part of the controller. Therefore, it is possible to inhibit noise from travailing to the outside of the receptacle.

In one embodiment, the controller includes an earth terminal that is electrically connected to the electrically conductive wall of the receptacle.

In another embodiment, the controller includes an IC chip with a switching device, so that a pulsed voltage is generated by the actuation of the switching device and is supplied to the motor. The IC chip is surrounded by the electrically conductive wall. The IC chip may be mounted to a circuit board disposed within the receptacle.

In a further embodiment, the controller farther includes a noise filtration circuit including a choke coil and a capacitor mounted to the circuit board. The capacitor is surrounded by the electrically conductive wall.

In a still further embodiment, the receptacle includes a first portion extending to the outside of the fuel tank and a second portion extending into the inner space of the fuel tank. The second portion includes the electrically conductive wall.

The first portion may be integrally formed with the cover and the second portion may be integrated with the first portion by an insertion molding process.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of a fuel supply system according to an embodiment of the present invention;

FIG. 2 is an enlarged vertical sectional view of a cover or a flange of the fuel supply system and showing a sectional view taken along line II-II in FIG. 3;

FIG. 3 is a plan view of a fuel tank incorporating the fuel supply system;

FIG. 4 is a schematic circuit configuration of a controller of the fuel supply system; and

FIG. 5 is a schematic view of a known fuel supply system.

DETAILED DESCRIPTION OF THE INVENTION

Each of the additional features and teachings disclosed above and below may be utilized separately or in conjunction with other features and teachings to provide improved fuel supply systems. Representative examples of the present invention, which examples utilize many of these additional features and teachings both separately and in conjunction with one another, will now be described in detail with reference to the attached drawings. This detailed description is merely intended to teach a person of skill in the art further details for practicing preferred aspects of the present teachings and is not intended to limit the scope of the invention. Only the claims define the scope of the claimed invention. Therefore, combinations of features and steps disclosed in the following detailed description may not be necessary to practice the invention in the broadest sense, and are instead taught merely to particularly describe representative examples of the invention. Moreover, various features of the representative examples and the dependent claims may be combined in ways that are not specifically enumerated in order to provide additional useful embodiments of the present teachings.

An embodiment according to the present invention will now be described with reference to FIGS. 1 to 4.

<General Construction of Fuel Supply System>

A fuel supply system 10 is configured to supply a fuel from a fuel tank 11 to injectors (not shown) under pressure. As shown in FIG. 1, the fuel supply system 10 generally includes a pump assembly 20 disposed within the fuel tank 11, and a flanged lid or cover 30 for closing an opening 13 formed in an upper wall of the fuel tank 11.

The pump assembly 20 includes a reservoir cup 21 with an upper opening, a fuel pump 23, a suction filter 24, a high-pressure filter 25 and a pressure regulator 26. The reservoir cup 21 is disposed within the fuel tank 11 and is placed on the bottom of the fuel tank 11 The fuel pump 23 is disposed within the reservoir cup 21. In this embodiment the fuel pump 23 is configured as a motor integrated pump having an impeller pump section and a motor section. The impeller pump section serves to draw, pressurize and discharge the fuel under pressure. The motor section can drive the pump section.

The suction filter 24f is attached to a fuel suction port 23e of the fuel pump 23, so that the fuel within the reservoir cup 21 is filtered by the suction filter 24_f before entering the fuel pump 23. Due to the pumping action of the impeller that rotates within a pump chamber the fuel is drawn into the fuel pump 23 via the suction filter 24f and the fuel suction port 23e and is pressurized within the pump chamber. The pump chamber can be defined by a groove(s) formed in the pump section along the flow path of the fuel. The pressurized fuel then flows into the motor section, so that the fuel cools the motor section. Also the pressurized fuel serves to lubricates and wash the rotary portions of the motor section. Thereafter, the pressurized fuel is discharged via a discharge port 23u provided on the upper end of the fuel pump 23. The fuel discharged from the discharge port 23u is delivered to the high-pressure filter 25 via a discharge-side pipeline 24. The high-pressure filter 25 can remove particles from the fuel. The particles may be contained in the fuel when the fuel flows through the motor section. After passing through the high-pressure filter 25, the fuel pressure is adjusted to a suitable value by the pressure regulator 26 and the fuel is further delivered to the injectors via an external fuel supply pipe (not shown), located outside of the fuel tank 11, and a fuel delivery pipe (not shown). The fuel is then injected into combustion chambers of an internal combustion engine (not shown).

<Cover or Flange>

The flanged lid or cover 30 is formed mainly of resin and includes a flange body portion 32 and a receptacle portion 40. The flange body portion 32 is adapted to close the upper opening 13 of the fuel tank 11. The receptacle portion 40 serves to receive a controller 50 that can control the operation of the motor of the fuel pump 23. As shown in FIG. 3, the flange body portion 32 has a disk-like configuration. A cylindrical positioning projection 32t is formed on the lower surface of the flange body portion 32 and is fitted into the upper opening 13 of the tank 11 (see FIG. 1). In addition, a retainer portion 32p extends from the peripheral edge of the positioning projection 32t so as to be pressed against the peripheral portion of the upper opening 13 of the tank 11 from the outer side of the tank 11.

As shown in FIG. 3, the receptacle portion 40 is positioned adjacent to the peripheral portion of the cover 30 and extends upward and downward from the cover 30 as shown in FIG. 2.

The receptacle portion 40 has a substantially tubular configuration and includes a closed bottom and an open top that is closed by a cover 44, so that a substantially closed space is defined within the receptacle portion 40. More specifically, the receptacle portion 40 has an outer-side part 41 and an inner-side part 43. The outer-side part 41 extends outward (upward as viewed in FIG. 2) from the flange body portion 32. The inner-side part 43 extends inward (downward as viewed in FIG. 2) from the flange body portion 32 into the inner space of the fuel tank 11. A connector 52 for the controller 50 is formed on the outer lateral wall of the outer-side part 41. An opening 41k is formed on the top of the outer-side part 41 of the receptacle portion 40 in order to enable insertion of the controller 50 into the receptacle portion 40. The cover 44 made of resin is attached to the receptacle portion 40 in order to close the opening 41k.

The inner-side part 43 is configured as a bottomed cylindrical housing and may be formed of electrically conductive metal material. A flange-like enlarged portion 43f is formed on the outer periphery of the upper end of the inner-side part 43 and can be joined to the outer-side part 41 when the outer-side part 41 is molded. Thus, the inner-side part 43 with the enlarged portion 43f is inserted into a mold that is prepared for molding the flange body portion 32 and the outer-side part 41 of the receptacle portion 40. The enlarged portion 43f is positioned within a portion of the mold cavity corresponding to the lower end portion of the outer-side part 41. Therefore, the enlarged portion 43f is inserted into the resin that forms the lower end portion of the outer-side part 41 by the molding process. In this way, the outer-side part 41 is integrated with the inner-side part 43 to form the bottomed cylindrical receptacle 40 by the molding process of the flange body portion 32 and the outer-side part 41.

<Controller>

As shown in FIG. 4, the controller 50 can be electrically connected to an engine control unit (hereinafter called “ECU”) by connecting an electrical connector CN, which extends from the ECU, to the connector 52 of the receptacle 40. Based on a signal Sg supplied from the ECU, the controller 50 actuates a switching element (not shown) provided on an IC chip 55. In response to the actuation of the switching element, a voltage signal (a battery voltage Vb in this embodiment) applied to a motor M of the motor section of the fuel pump 23 is switched on and off, so that a pulsed voltage signal is produced. Therefore, adjusting a pulse width or a value equivalent to the pulse width based on the signal Sg from the ECU can vary a mean voltage Vav applied to the motor M in order to control the output of the motor M. Hence, it is possible to keep a constant fuel pressure within the delivery pipe to which the injectors are connected. In the embodiment shown in FIG. 4, the voltage Vb is a voltage of a battery as a power source and also is a power source voltage of the ECU.

Because the controller 50 generates a pulsed voltage by the actuation of the switching element, noise may be produced during the actuation of the switching element. Therefore, a filtration circuit 56 is provided in a power supply line P for the controller 50 in order to absorb noise that may be produced at the IC chip 55, so that the noise is prevented from traveling to the side of the ECU. The filtration circuit 56 includes a choke coil 56t and a capacitor 56c. The filtration circuit 56 as will as the IC chip 55 is mounted to a circuit board 57 of the controller 50 (see FIG. 2). In FIG. 2, a symbol E designates an earth terminal of the circuit board 57.

IC chip 55 further includes a speed measuring device (no shown). The speed measuring device can measure the rotational speed of the motor M and can output a rotational speed signal F that is supplied to the ECU for a feedback control.

<Mounting Structure of Controller>

As shown in FIG. 2, the controller 50 is disposed within the receptacle portion 40 of the cover 30 in such a manner that the circuit board 57 is positioned to extend substantially vertically. As described above, the IC chip 55, the capacitor 56c and the choke coil 56t are mounted to the circuit board 57. The IC chip 55, the circuit board 57 and a part of the choke coil 56t are positioned within the inner-side part 43 of the receptacle 40, which is formed of electrically conductive metal material. A leaf spring 57b formed of electrically conductive material is connected to the earth terminal E of the circuit board 57 and is resiliently deformed between the circuit board 57 and an inner wall of the inner-side part 43, so that the leaf spring 57b contacts with the inner wall of the inner-side part 43. Therefore, the earth terminal E and the inner-side part 43 are electrically connected by the leaf spring 57b.

Further, although not shown in the drawings, a member having high heat conductivity may be disposed between the circuit board 57 and the inner wall of the inner-side part 43, so that the heat that may be produced by the switching element of the IC chip 55 can be easily conducted to the inner-side part 43. Because the fuel may contact with the outer surface of the inner-side part 43, the fuel may cool the inner-side part 43. Therefore, the fuel serves to absorb the heat produced at the IC chip 55.

<Advantages of Fuel Supply System>

According to the fuel supply system 10 of this embodiment; the electrically conductive wall of the inner-side part 43 of the receptacle 40 surrounds the electrical elements of the controller 50, which may produce nose and include the switching element mounted to the IC chip 55, and the capacitor 56c disposed adjacent to the IC chip 55. In other words, the electrically conductive wall of the inner-side part 43 of the receptacle 40 serves as an electrical shield for preventing noise from traveling to the outside of the receptacle 40 via the inner-side part 43. Therefore, it is possible to reduce the influence of the noise on the ECU or other outside controller. It is not necessary to construct the filtration circuit 50 to have a complicated construction. As a result, the influence of the noise that may be produced by the controller 50 can be effectively reduced without increase in the manufacturing cost.

In addition, the electrically conductive wall or the wall of the inner-side part 43 is electrically connected to the earth terminal E of the controller 50 via the electrically conductive leaf spring 57b. Therefore, the electrical connection between the electrically conductive wall and the earth terminal E can be reliably maintained for a long time without causing accidental disconnection by an external force, such as vibrations, that may be applied to the receptacle 40.

Further, because the fuel within the tank 11 can contact with the outer surface of the inner-side part 43 that extends into the inner space of the tank 11, the fuel can cool the inner-side part 43 and can eventually cool the controller 50 disposed therein.

Alterative Embodiments

The invention may not be limited to the above embodiment but may be modified in various ways without departing from the sprits of the invention. For example, in the above embodiment, the outer-side part 41 of the receptacle 40 is formed of resin while the inner-side part 43 is formed of electrically conductive metal. However, the outer-side part 41 also may be formed of metal.

In addition, the inner-side part 43 and/or the outer-side part 41 may be formed of resin that contains metal powder for providing electrical conductivity. It is also possible to form the inner-side part 43 and/or the outer-side part 41 of resin, while an electrically conductive material layer is formed on the inner wall surface.

Further, although the cover 30 and the pump assembly 20 are separated from each other in the above embodiment, the cover 30 and the pump assembly 20 may be integrated into one assembly.

Claims

1. A fuel supply system for supplying a fuel from a vehicle fuel tank, comprising:

a fuel pump disposed within the fuel tank;

a cover capable of closing an opening formed in an upper portion of the fuel tank, wherein the cover includes a receptacle; and

a controller capable of controlling the operation of a motor of the fuel pump, wherein the controller includes an earth terminal and electrical elements that may produce noise;

wherein the receptacle has an electrically conductive wall surrounding at least the electrical elements of the controller; and

wherein the electrically conductive wall is electrically connected to the earth terminal of the controller.

2. The fuel supply system as in claim 1, wherein the controller is operable to produce a pulsed voltage by the actuation of a switching element in order to control a mean voltage applied to the motor.

3. The fuel supply system as in claim 1, wherein the electrically conductive wall of the receptacle is formed of metal.

4. The fuel supply system as in claim 1, wherein the electrically conductive wall of the receptacle is formed of resin containing electrically conductive material.

5. The fuel supply system as in claim 1, wherein the electrically conductive wall comprises a resin layer and an electrically conductive material layer.

6. The fuel supply system as in claim 1, further comprising a spring constructed to resiliently hold the connecting condition between the electrically conductive wall and the earth terminal of the controller.

7. The fuel supply system as in claim 1, wherein the receptacle at least partly extends in to the inner space of the fuel tank, so that the fuel within the fuel tank can contact with the receptacle.

8. A fuel supply system used in combination with a fuel tank, comprising:

a fuel pump including a motor;

a controller capable of controlling the motor; and

a receptacle capable of receiving the controller,

wherein the receptacle is mounted to the fuel tank and includes a noise-shielding wall capable of shielding noise of the controller.

9. The fuel supply system as in claim 8, wherein the noise-shielding wall comprises an electrically conductive wall surrounding at least a part of the controller.

10. The fuel supply system as in claim 9, wherein:

the controller includes an earth terminal; and

the earth terminal is electrically connected to the electrically conductive wall of the receptacle.

11. The fuel supply system as in claim 10, further comprising an electrically conductive spring that can resiliently contact with the electrically conductive wall and the earth terminal in order to provide electrical connection therebetween.

12. The fuel supply system as in claim 9, wherein:

the controller comprises an IC chip including a switching device, so that a pulsed voltage is generated by the actuation of the switching device and is supplied to the motor; and

the IC chip is surrounded by the electrically conductive wall.

13. The fuel supply system as in claim 12, wherein:

the IC chip is mounted to a circuit board disposed within the receptacle.

14. The fuel supply system as in claim 13, wherein:

the controller further comprises a noise filtration circuit including a choke coil and a capacitor mounted to the circuit board; and

the capacitor is surrounded by the electrically conductive wall.

15. The fuel supply system as in claim 9, wherein the electrically conductive wall of the receptacle is formed of metal.

16. The fuel supply system as in claim 9, wherein the electrically conductive wall of the receptacle is formed of electrically conductive resin.

17. The fuel supply system as in claim 9, wherein the electrically conductive wall comprises a resin wall layer and an electrically conductive material layer.

18. The fuel supply system as in claim 9, wherein:

the fuel tank has an opening permitting communication between the inner space of the fuel tank and the outside of the fuel tank;

the fuel supply system further includes a cover constructed to close the opening of the fuel tank; and

the receptacle is provided on the cover

19. The fuel supply system as in claim 18, wherein:

the receptacle comprises a first portion extending to the outside of the fuel tank and a second portion extending into an inner space of the fuel tank; and

the second portion comprises the electrically conductive wall.

20. The fuel supply system as in claim 19, wherein the first portion is integrally formed with the cover and the second portion is integrated with the first portion by an insertion molding process.