Mechanism for restraining fuel pressure pulsation and high pressure fuel supply pump of internal combustion engine with such mechanism

Patent metadata

Field	Value
Publication number	US-9709055-B2
Application number	US-201414497755-A
Country	US
Kind code	B2
Filing date	Sep 26, 2014
Priority date	Apr 25, 2008
Publication date	Jul 18, 2017
Grant date	Jul 18, 2017

Abstract

A mechanism for reducing pressure pulsation includes a pair of metal dampers formed by joining two disk-shaped metal diaphragms over an entire circumference and forming a hermetically sealed space inside a joined portion. Gas is sealed in the aforementioned hermetically sealed space of the damper, and a pair of pressing members give pressing forces to both outer surfaces of the aforementioned metal dampers at a position at an inner diameter side from the joined portion. The mechanism is unitized, with the pair of pressing members being connected in a state in which they sandwich the metal damper.

First claim

The invention claimed is:

1. A fuel supply pump comprising:
a pump housing;
a pressurizing chamber that is formed in the pump housing;
a plunger that is configured to move reciprocally and change a volume of the pressurizing chamber;
a plunger seal that is in slidable contact with an outer periphery of the plunger;
a damper chamber that is formed on an opposite side of the pressurizing chamber from the plunger, the damper chamber containing a metal damper therein;
a seal chamber that is formed between the plunger seal and an end portion of the pump housing, the seal chamber being positioned on an opposite side from the damper chamber;
an intake joint that is provided on a side peripheral surface of the pump housing, the intake joint having a fuel passage that is configured to introduce fuel into the pump housing; and
an intake passage that is formed in the pump housing, the intake passage connecting the damper chamber and the seal chamber; wherein
the fuel passage in the intake joint is connected to a branching portion of the intake passage, the branching portion being located at a middle of the intake passage; and
the intake passage is formed in a direction parallel to a direction of reciprocal movement of the plunger so that a first region of the intake passage, in which fuel flows to the damper chamber from the branching portion, and a second region of the intake passage, in which fuel flows to the seal chamber from the branching portion, are positioned on a same straight line,
wherein the pump housing has a concave portion in which a part of the seal chamber is located, and the concave portion is located to overlap with the branching portion of the intake passage along the direction of reciprocal movement of the plunger.

2. The fuel supply pump according to claim 1 , wherein
the pump housing has a single straight through hole that extends along the direction of reciprocal movement of the plunger, and the single straight through hole comprises the first region of the intake passage and the second region of the intake passage.

3. The fuel supply pump according to claim 1 , wherein
the fuel passage in the intake joint is formed in a direction perpendicular to a longitudinal direction of a longest straight portion of the intake passage.

4. The fuel supply pump according to claim 1 , wherein
an inner diameter of the concave portion is larger than an inner diameter of a sliding portion of a cylinder that slidably holds the plunger.

5. The fuel supply pump according to claim 1 , wherein
the plunger is biased by a spring in a direction away from the pressurizing chamber, and
a part of the seal chamber is defined in a holder that holds the plunger seal and the spring.

6. The fuel supply pump according to claim 5 , wherein
the holder is fixed into the concave portion of the pump housing, the concave portion being located to overlap the branching portion of the intake passage along the direction of reciprocal movement of the plunger.

7. The fuel supply pump according to claim 1 , wherein
the intake passage is formed so that the damper chamber and the seal chamber are directly communicated in the direction of reciprocal movement of the plunger.

8. The fuel supply pump according to claim 7 , wherein
the metal damper in the damper chamber is arranged in a position to overlap the intake passage in a longitudinal direction of the intake passage.

9. The fuel supply pump according to claim 7 , wherein
the damper chamber is provided fluidically between the seal chamber and the pressurizing chamber.

10. The fuel supply pump according to claim 7 , wherein
the damper chamber is formed between the pump housing and a damper cover, the damper cover being fixed to the pump housing, and
the metal damper is held by a first holding member and a second holding member so that the metal damper is not in a direct contact with the damper cover and the pump housing.

11. The fuel supply pump according to claim 10 , wherein
the first holding member is arranged between the metal damper and the damper cover,
the second holding member is arranged between the metal damper and the pump housing, and
the metal damper is in contact with the second holding member in a space of the damper cover side with respect to an uppermost end portion of the pump housing.

12. The fuel supply pump according to claim 10 , wherein
the first holding member is arranged between the metal damper and the damper cover,
the second holding member is arranged between the metal damper and the pump housing, and
the metal damper is in contact with the second holding member in a space of the damper cover side in a moving direction of the plunger with respect to a connection portion of the pump housing and the damper cover.

13. The fuel supply pump according to claim 10 , wherein
the first holding member is arranged between the metal damper and the damper cover,
the second holding member is arranged between the metal damper and the pump housing, and
the metal damper is in contact with the second holding member in a space radially outward with respect to the intake passage.

Assignees

• Hitachi Automotive Systems Ltd

Inventors

• Usui Satoshi
• Tamura Shingo
• Miyazaki Katsumi
• Takahashi Sunao
• Suganami Masayuki
• Hashida Minoru

Classifications

• F04B39/125

  Cylinder heads · CPC title

• F02M59/442

  means preventing fuel leakage around pump plunger, e.g. fluid barriers · CPC title

• F02M55/04 Primary

  Means for damping vibrations {or pressure fluctuations} in injection pump inlets {or outlets} · CPC title

• F02M59/48

  Assembling; Disassembling; Replacing · CPC title

• F02M37/0041

  Means for damping pressure pulsations (equalisation of pulses in positive displacement pumps F04B1/00; devices for damping fluid pulsations in pipes F16L55/04) · CPC title