High-pressure fuel pump

Patent metadata

Field	Value
Publication number	US-10247181-B2
Application number	US-201615041874-A
Country	US
Kind code	B2
Filing date	Feb 11, 2016
Priority date	Nov 16, 2005
Publication date	Apr 2, 2019
Grant date	Apr 2, 2019

Abstract

A high-pressure fuel pump includes a pressurizing chamber for pressurizing fuel, an outlet valve for discharging the fuel pressurized in the pressurizing chamber to an outlet passage, a relief passage for connecting the outlet passage located downstream of the outlet valve and the pressurizing chamber with each other while bypassing the outlet valve. A relief valve device is provided in the relief passage and adapted to open when an internal pressure of the outlet passage becomes higher than that of the pressurizing chamber, thereby providing communication between the outlet passage and the pressurizing chamber. The relief valve includes a relief spring mechanism for pressing a relief valve to a relief valve seat. At least the relief spring mechanism among members of the relief valve device is provided outside the pressurizing chamber in the pump body.

First claim

What is claimed is:

1. A high-pressure fuel pump comprising:
a pressurizing chamber which is formed in a pump body;
an outlet valve device which is disposed on an outlet passage side of the pressurizing chamber;
a relief valve device which is disposed in a relief passage fluidly connecting an outlet passage to the pressurizing chamber, while bypassing the outlet valve device, wherein
the relief valve device includes a relief valve, a relief valve seat, and a relief spring configured to pull the relief valve toward the relief valve seat,
the relief valve device in the relief passage is fixed so as to close an aperture connecting to the pressurizing chamber, and
the relief spring is disposed outside of the pressurizing chamber, wherein
the pump body defines a cavity into which the relief valve is inserted, the cavity having a first longitudinal end and a second longitudinal end that is opposite to the first longitudinal end,
the second longitudinal end is located at an outermost surface of the pump body, and

the relief valve opens along a direction that is away from the second longitudinal end of the cavity.

2. The high-pressure fuel pump according to claim 1 , wherein the valve seat has a seat surface formed on a pressurizing chamber side.

3. The high-pressure fuel pump according to claim 2 , wherein the valve seat has a spring receiving surface formed on an opposite side from the seat surface.

4. The high-pressure fuel pump according to claim 1 , wherein the relief valve is formed in a spherical-surface shape.

5. The high-pressure fuel pump according to claim 1 , further comprising:
an inlet valve device which is disposed on an inlet passage side of the pressurizing chamber; wherein
the inlet valve device includes an inlet valve, an inlet valve seat, and a spring configured to urge the inlet valve via a plunger, and
the spring is disposed on an opposite side of the inlet valve seat from the pressurizing chamber.

6. The high-pressure fuel pump according to claim 1 , wherein the relief valve device forms an independent unit as an assembly.

7. The high-pressure fuel pump according to claim 6 , wherein the relief valve device is inserted into a through hole extending from a side wall of the pump body.

8. The high-pressure fuel pump according to claim 1 , further comprising:
a pressure damper configured to reduce pressure pulsation; and
a cut-off valve configured to allow fuel to flow only in a direction toward the pressurizing chamber from an inlet joint, wherein the cut-off valve is disposed on an upstream side of the pressure damper.

9. The high-pressure fuel pump according to claim 8 , wherein the cut-off valve is provided with a hole.

10. The high-pressure fuel pump according to claim 1 , wherein
the relief valve device further includes a relief valve rod connected to the relief valve, and
the relief spring is configured to pull the relief valve toward the relief valve seat by pressing the relief valve rod in a direction away from the relief valve seat.

11. The high-pressure fuel pump according to claim 1 , wherein the aperture is formed on a peripheral side face of the pressurizing chamber.

12. The high-pressure fuel pump according to claim 1 , wherein the aperture is formed on a top of the pressurizing chamber.

13. The high-pressure fuel pump according to claim 1 , wherein an inner peripheral surface of the relief passage forms the aperture.

14. A high-pressure fuel pump comprising:
a pressurizing chamber which is formed in a pump body;
an outlet valve device which is disposed on an outlet passage side of the pressurizing chamber;
a relief valve device which is disposed in a relief passage fluidly connecting an outlet passage to the pressurizing chamber, while bypassing the outlet valve device, wherein
the relief valve device includes a relief valve and a relief valve seat against which the relief valve abuts,
the pressurizing chamber includes a top wall forming the top of the pressurizing chamber, the top wall including a bottom surface facing the pressurizing chamber and an opposing top surface facing away from the pressurizing chamber, wherein the relief valve seat is disposed within a recess formed in the top surface,
the pump body defines a cavity into which the relief valve is inserted, the cavity having a first longitudinal end and a second longitudinal end that is opposite to the first longitudinal end, the second longitudinal end is located at an outermost surface of the pump body, and
the relief valve opens along a direction that is away from the second longitudinal end of the cavity.

15. A high-pressure fuel pump comprising:
a pressurizing chamber which is formed in a pump body;
an outlet valve device which is disposed on an outlet passage side of the pressurizing chamber;
a relief valve device which is disposed in a relief passage fluidly connecting an outlet passage to the pressurizing chamber, while bypassing the outlet valve device, wherein
the relief valve device includes a relief valve, a relief valve seat, and a relief spring configured to pull the relief valve toward the relief valve seat,
the relief valve device includes a holder welded to the relief valve seat, the holder containing the relief spring therein,
the holder is fixed within a mounting hole formed in the pump body, the mounting hole opening directly to an inlet passage of the pump,
the relief valve being disposed in the mounting hole, the mounting hole having a first longitudinal end and a second longitudinal end that is opposite to the first longitudinal end, the second longitudinal end is located at an outermost surface of the pump body, and
the relief valve opens along a direction that is away from the second longitudinal end of the cavity.

Assignees

• Hitachi Ltd

Inventors

• Usui Satoshi
• Yamada Hiroyuki
• Tokuo Kenichiro
• Onose Toru
• Abe Masami

Classifications

• F02M59/366

  Valves being actuated electrically · CPC title

• F04B53/1002

  Ball valves · CPC title

• F04B53/16

  Casings; Cylinders; Cylinder liners or heads; Fluid connections · CPC title

• F02M59/462

  Delivery valves · CPC title

• F04B53/10

  Valves; Arrangement of valves · CPC title