Fuel supply for international combustion engine

• US 5,785,025 A
• Filed: 09/12/1997
• Issued: 07/28/1998
• Est. Priority Date: 06/09/1995
• Status: Expired due to Fees

• Current Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Original Assignee: Nippondenso Co., Ltd. (DENSO Corporation)
• Inventors: Miwa, Makoto, Yoshiume, Naoki, Isomura, Shigenori
• Primary Examiner(s): Moulis, Thomas N.
• Application Number:
  US08/928,401
• Time in Patent Office: 319 Days
• Field of Search: 123/497, 123/514, 123/509, 123/511, 123/457-8, 123/459
• US Class Current: 123/497
• CPC Class Codes: F02D 2200/0602 Fuel pressure
• CPC Class Codes: F02D 2250/31 Control of the fuel pressure
• 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 41/123 the fuel injection being cut-off
• CPC Class Codes: F02D 41/22 Safety or indicating devices for abnormal conditions in air/fuel ratio feedback systems F02D41/1495, in electric control linkage F02D11/107, in purge control systems F02M25/0809
• CPC Class Codes: F02D 41/3082 Control of electrical fuel pumps
• CPC Class Codes: F02D 41/3818 for petrol engines
• 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 37/0058 Returnless fuel systems, i.e. the fuel return lines are not entering the fuel tank
• CPC Class Codes: F02M 37/10 submerged in fuel, e.g. in reservoir
• CPC Class Codes: F02M 69/462 Arrangement of fuel conduits, e.g. with valves for maintaining pressure in the pipes after the engine being shut-down
• CPC Class Codes: F02M 69/54 Arrangement of fuel pressure regulators

Abstract

In a fuel supply system employing a returnless fuel pipe arrangement, a relief valve is provided at a discharge side of a fuel pump. The relief valve is opened when fuel pressure in the fuel pipe arrangement becomes no less than a system protective pressure, so as to relieve the fuel pressure to protect the system. The relief valve is also arranged to be open when the fuel pressure in the fuel pipe arrangement becomes higher than a target fuel pressure by a predetermined value or when the fuel cut is performed. Thus, the fuel pressure in the fuel pipe arrangement is lowered. Thereafter, when the fuel pressure in the fuel pipe arrangement is lowered to a pressure near the target fuel pressure, the relief valve is arranged to be closed so that the fuel pressure in the fuel pipe arrangement is held substantially at the target fuel pressure.

Claims

1. A fuel supply system for an internal combustion engine, and fuel supply system having a returnless fuel pipe arrangement in which no fuel return line is provided for returning an excessive portion of fuel, delivered under pressure from a fuel pump to a fuel injector, to a fuel tank, said fuel supply system comprising:

fuel pressure control means for controlling said fuel pump so as to converge a fuel pressure in said fuel pipe arrangement to a target fuel pressure;

a check valve provided at a fuel discharge port of said fuel pump; and

function stopping means for stopping a function of said check valve under a predetermined condition.

2. The fuel supply system according to claim 1, wherein said fuel pressure control means includes means for reducing a fuel discharge of said fuel pump under said predetermined condition.

3. The fuel supply system according to claim 1, wherein said fuel pressure control means stops said fuel pump under said predetermined condition.

4. The fuel supply system according to claim 1, wherein said fuel pressure control means rotates said fuel pump in a reverse direction under said predetermined condition.

5. The fuel supply system according to claim 1, wherein said check valve includes a solenoid, and said function stopping means stops the function of said check valve by energizing said solenoid.

6. The fuel supply system according to claim 1, wherein said function stopping means stops the function of said check valve when the fuel pressure in said fuel pipe arrangement becomes higher than the target fuel pressure by a predetermined value.

7. The fuel supply system according to claim 1, wherein said function stopping means stops the function of said check valve when fuel cut is performed to stop fuel injection from said fuel injector.

8. The fuel supply system according to claim 7, wherein said fuel pressure control means includes means for controlling, during the fuel cut, the fuel pressure in said fuel pipe arrangement to approximate to a value which represents the target fuel pressure for fuel injection upon returning from the fuel cut.