Fuel supply system responsive to engine fuel demand

• US 6,279,541 B1
• Filed: 12/01/2000
• Issued: 08/28/2001
• Est. Priority Date: 12/01/2000
• Status: Expired due to Fees

• Current Assignee: TI Group Automotive Systems LLC
• Original Assignee: Walbro Corporation (Sun Capital Partners Incorporated)
• Inventors: Maschke, Edwyn R., Kuperus, Peter P., Gettel, Bryan J., Talaski, Edward J., Kuenzli, Ronald B., Doane, Kirk D.
• Primary Examiner(s): MILLER, CARL STUART
• Application Number:
  US09/727,616
• Time in Patent Office: 270 Days
• Field of Search: 123/514, 123/497, 123/456, 123/506, 123/357
• US Class Current: 123/497
• CPC Class Codes: F02D 33/003 Controlling the feeding of liquid fuel from storage containers to carburettors or fuel-injection apparatus control of electrical fuel pumps F02D41/3082, controlling fuel flow to a common rail F02D41/3845; Failure or leakage prevention; Diagnosis or detection of failure; Arrangement of sensors in the fuel system; Electric wiring; Electrostatic discharge
• CPC Class Codes: F02D 41/3082 Control of electrical fuel pumps
• CPC Class Codes: F02D 41/3809 Common rail control systems common rail apparatus F02M55/025, F02M63/0225
• CPC Class Codes: F02M 2037/087 Controlling fuel pressure valve
• CPC Class Codes: F02M 37/0029 Pressure regulator in the low pressure fuel system pressure regulator in low-pressure injection apparatus F02M69/54
• CPC Class Codes: F02M 37/0052 Details on the fuel return circuit; Arrangement of pressure regulators
• CPC Class Codes: F02M 69/54 Arrangement of fuel pressure regulators

Abstract

A no-return system for supplying fuel from a tank to a fuel injected internal combustion engine of an automotive vehicle in response to the fuel demand of the engine. The pump supplies more fuel than that required by the operating engine and the excess fuel is diverted from the engine by a bypass fuel pressure regulator and returned to the tank through a fluid-activatable switch movable to electrically open and closed states in response to the rate of flow of excess fuel through the switch. An electric control circuit is responsive to the state of the switch to change the magnitude of the power applied to the electric motor to change its operating speed and thereby modulate the output fuel flow rate of the pump in response to the fuel demand of the engine.

Claims

1. An apparatus for supplying fuel in a fuel system to an internal combustion engine comprising:

an electric motor for driving a fuel pump;

a fuel pump having an outlet configured to deliver fuel to the engine;

a bypass fuel pressure regulator communicating with the pump outlet to regulate the pressure of fuel supplied to the engine and configured to divert excess fuel flow from the engine in response to the fuel demand of the engine;

a fluid-activatable switch communicating with the pressure regulator and receiving the excess fuel from the pressure regulator and returning the excess fuel to a fuel tank; and

an electric control circuit electrically connected to the switch, capable of being electrically connected to an electric voltage power source and to the electric motor for supplying an electric current to the electric motor;

wherein said switch is manipulable into an electrically open position and an electrically closed position as determined by the rate of flow of excess fuel from the pressure regulator; and

wherein said control circuit is capable of adjusting the magnitude of the power of the current supplied to the electric motor as dictated by the position of the switch such that the speed of said electric fuel pump motor is modulated in accordance with changes in the rate of flow of excess fuel and the position of the switch.

2. The apparatus according to claim 1, wherein said fluid-activatable switch comprises:

an elongate body having an inlet opening at one end, a stop opening at the opposite end, at least one outlet opening, and a longitudinal chamber in communication with said inlet opening, said stop opening, and said at least one outlet opening;

a plunger, slidingly received within said chamber, having a shoulder portion proximate said at least one outlet opening in said body, and a single electrically conductive contact mounted on said shoulder portion proximate said inlet opening;

an adjustable stop received in said stop opening having a tail portion extending into said chamber and an exposed head portion;

a yieldable and resilient biasing element, received between said plunger and said stop, having a first end bearing and abutting said tail portion of said stop and a second end extending into said chamber and abutting said plunger; and

a pair of electrically conductive contacts electrically connected to said electric control circuit and exposed within said chamber of said body substantially between said inlet opening and said at least one outlet opening;

wherein said chamber of said body defines a fuel flow path from said inlet opening to said at least one outlet opening, said single contact and said shoulder portion of said plunger are situated in said fuel flow path and yieldably biased against fuel flowing within said fuel flow path, said plunger is capable of being moved as dictated by the rate of the excess fuel flowing along said fuel flow path such that said switch is in one of said electrically open position and said electrically closed position, and said open position is defined as said single contact being separated from said pair of contacts and said closed position is defined as said single contact being in electrical contact with said pair of contacts.

3. The apparatus according to claim 2, wherein said longitudinal chamber is substantially cylindrical.

4. The apparatus according to claim 3, wherein said inlet opening and said stop opening are substantially aligned with the longitudinal axis of said longitudinal chamber.

5. The apparatus according to claim 3, wherein said shoulder portion of said plunger is substantially cylindrical and has a cross-sectional area that approaches the cross-sectional area of said longitudinal chamber.

6. The apparatus according to claim 2, wherein each of said at least one outlet opening is defined within a common middle portion of said elongate body.

7. The apparatus according to claim 2, wherein said adjustable stop and said stop opening are both threaded such that said stop is adjustably threadingly received in said stop opening.

8. The apparatus according to claim 2, wherein said stop is one of a plug and a cup-shaped closure.

9. The apparatus according to claim 2, wherein said resilient biasing element is a spring.

10. The apparatus according to claim 2, wherein said plunger has a plurality of integral fins in sliding contact with the inner surface of said elongate body.

11. The apparatus according to claim 2, wherein said single electrically conductive contact is an annular disc of metal.

12. The apparatus according to claim 11, wherein said plunger has a stem integral with said shoulder portion and extending toward said inlet opening, and said annular disc is adjustably fixed on said stem proximate the extended end of said stem.

13. The apparatus according to claim 12, wherein said longitudinal chamber is substantially cylindrical, and said inlet opening and said stem are substantially aligned with the longitudinal axis of said longitudinal chamber.

14. The apparatus according to claim 2, wherein said single electrically conductive contact is an annular ring of metal.

15. The apparatus according to claim 14, wherein said plunger has a pocket integral with said shoulder portion and facing said inlet opening, and said annular ring is fixedly seated in said pocket such that said annular ring extends toward said inlet opening partially beyond the confines of said pocket.

16. The apparatus according to claim 2, wherein said pair of electrically conductive contacts is a pair of prongs of metal.

17. The apparatus according to claim 16, wherein said elongate body has a plug opening substantially between said inlet opening and said at least one outlet opening, said fluid-activatable switch includes an electrically insulative plug casing sealingly situated within said plug opening, and said pair of prongs is mounted in said plug casing such that said prongs are at least partially exposed within said longitudinal chamber and are electrically connected to said electric voltage control circuit.

18. The apparatus according to claim 2, wherein said pair of electrically conducive contacts is a pair of flexible prongs of metal and sealingly mounted in the wall of said longitudinal chamber such that said flexible prongs protrude into said chamber substantially between said inlet opening and said at least one outlet opening.

19. The apparatus according to claim 18, wherein said elongate body includes a plurality of laminar flow guide structures integral with the wall of said longitudinal chamber and situated within said chamber proximate said inlet opening, and at least one of said laminar flow guide structures has a stop surface for physically limiting the extent of flexing of at least one of said flexible prongs when said fluid-activatable switch is in said electrically closed position.

20. The apparatus according to claim 1, wherein said electric control circuit comprises:

an electrically resistive circuit element; and

means for electrically sensing the position of said fluid-activatable switch and selectively connecting said resistive circuit element in electrical series with said electric motor and to said electric voltage power source as dictated by said sensed position of said switch.

21. The apparatus according to claim 20, wherein said electrically resistive circuit element is a resistor.

22. The apparatus according to claim 20, wherein said position sensing and selective connecting means comprises a field-effect transistor.

23. The apparatus of claim 1, wherein said fluid-activatable switch comprises:

an elongate body having an inlet opening at one end, an end outlet opening at the opposite end, at least one side outlet opening, and a longitudinal chamber in communication with said inlet opening, said end outlet opening, and said at least one side outlet opening;

an electrically conductive first contact, electrically connected to said electric control circuit, mounted and exposed within said chamber of said body proximate said end outlet opening;

an electrically conductive resilient biasing element having a first end electrically attached to said first contact and a second end extending into said chamber;

an electrically conductive plunger, slidingly received within said chamber, having a biased side electrically attached to said second end of said biasing element, and an impact side opposite said biased side and movably situated substantially between said inlet opening and said at least one side outlet opening in said body; and

an electrically conductive second contact, electrically connected to said electric control circuit, mounted and exposed within said chamber of said body substantially between said inlet opening and said at least one side outlet opening;

wherein said chamber of said body defines a fuel flow path from said inlet opening to said outlet openings, said plunger is situated within said fuel flow path and yieldably biased against fuel flowing within said fuel flow path, said plunger is capable of being moved as dictated by said fuel flowing within said fuel flow path such that said switch is in one of said electrically open position and said electrically closed position, and said open position is defined as said plunger being separated from said second contact and said closed position is defined as said plunger being in electrical contact with said second contact.

24. The apparatus according to claim 23, wherein said longitudinal chamber is at least substantially funnel-shaped between substantially said second contact and said at least one side outlet opening and cylindrical between substantially said at least one side outlet opening and said first contact.

25. The apparatus according to claim 23, wherein each of said at least one side outlet opening is defined within a common middle section of said elongate body between said first contact and said second contact.

26. The apparatus according to claim 23, wherein said resilient biasing element is a helical spring of metal.

27. The apparatus according to claim 23, wherein said electrically conductive plunger is substantially spherical.

28. The apparatus according to claim 27, wherein said longitudinal chamber is substantially cylindrical proximate said at least one side outlet opening, and the diameter of said spherical plunger substantially approaches the diameter of said longitudinal chamber proximate said at least one side outlet opening.

29. The apparatus according to claim 27, wherein said electrically conductive spherical plunger is a ball of metal.

30. The apparatus according to claim 23, wherein said electrically conductive second contact comprises a pair of metal prongs electrically shorted together.

31. The apparatus accordingly to claim 30, wherein said electrically conductive first contact comprises another pair of metal prongs electrically shorted together.

32. The apparatus according to claim 31, wherein said metal prongs of said second contact are substantially parallel to each other, and said metal prongs of said first contact are substantially parallel to each other.

33. The apparatus according to claim 1 wherein the fuel system is a returnless fuel system.

34. The apparatus according to claim 1 wherein the electric control circuit is configured to adjust the magnitude of the voltage of the current applied to the electric motor as dictated by the position of the switch.

35. The apparatus according to claim 1 wherein the control circuit is configured as a pulse width modulation circuit to adjust the power of the current applied to the electric motor as dictated by the position of the switch.