High pressure fuel pump and fuel supply system

Patent metadata

Field	Value
Publication number	US-11525427-B2
Application number	US-202117246804-A
Country	US
Kind code	B2
Filing date	May 3, 2021
Priority date	Jun 22, 2017
Publication date	Dec 13, 2022
Grant date	Dec 13, 2022

Abstract

A high pressure fuel pump includes: a pump body that forms a suction passage and a pressurizing chamber and slidably supports a plunger; and a control valve that opens a connection between the suction passage and the pressurizing chamber in a suction stroke, during which the plunger is driven toward a suction side for suctioning fuel into the pressurizing chamber, while the control valve controls closing timing, at which the connection between the suction passage and the pressurizing chamber is closed by the control valve in a delivery stroke, during which the plunger is driven toward a delivery side for delivering the fuel out of the pressurizing chamber. The pump body forms a release passage that is communicated with the suction passage. The release passage relieves the fuel, which is pressurized by the plunger, from the pressurizing chamber before the closing timing during the delivery stroke.

First claim

What is claimed is:

1. A high pressure fuel pump for delivering fuel, which is suctioned into a pressurizing chamber from a low pressure fuel pump through a suction passage, to a supply destination after pressurizing the fuel in the pressurizing chamber with a plunger, the high pressure fuel pump comprising:
a pump body that slidably supports the plunger and forms the suction passage, the pressurizing chamber, a cam receiving chamber, a release passage, an internal pressure variable chamber and a communication passage, wherein the pressurizing chamber is communicated with the suction passage and the release passage through a connection, and the release passage is communicated with the cam receiving chamber which receives a drive cam that is configured to drive the plunger, and an internal pressure of the internal pressure variable chamber is increased and decreased in response to reciprocation of the plunger, and the communication passage communicates between the internal pressure variable chamber and the cam receiving chamber;
a control valve that is configured to open and close the connection; and
a controller that is configured to control an operation of the control valve, wherein:
the controller is configured to place the control valve in an opening state where the control valve opens the connection to supply the fuel from the suction passage to the pressurizing chamber through the connection in a suction stroke, during which the plunger is driven toward a suction side for suctioning the fuel into the pressurizing chamber;
the controller is configured to place the control valve in a closing state where the control valve closes the connection at a closing timing in a delivery stroke, during which the plunger is driven toward a delivery side for delivering the fuel out of the pressurizing chamber upon pressurization of the fuel after the suction stroke;
the controller is configured to maintain the control valve in the opening state to relieve the fuel, which is pressurized by the plunger, from the pressurizing chamber to the cam receiving chamber through the connection and the release passage during the delivery stroke until the closing timing reaches after a start of the delivery stroke;
the release passage is communicated with the suction passage through the connection; and
the connection is configured to conduct the fuel from the pressurizing chamber to the release passage and thereafter to the cam receiving chamber in a case where a fuel pressure in the pressurizing chamber is higher than a fuel pressure in the cam receiving chamber in the opening state of the control valve.

2. The high pressure fuel pump according to claim 1 , wherein:
the pump body forms a drain passage that drains the fuel from the cam receiving chamber to a fuel tank.

3. The high pressure fuel pump according to claim 2 , wherein:
a passage cross-sectional area of a portion of the release passage is reduced on a side of the cam receiving chamber, at which the suction passage is placed, to form a release flow restricting portion; and
a passage cross-sectional area of at least a portion of the drain passage is reduced in comparison to a passage cross-sectional area of the release flow restricting portion.

4. The high pressure fuel pump according to claim 1 , wherein the connection is configured to conduct the fuel from the release passage to the pressurizing chamber in a case where the fuel pressure in the pressurizing chamber is lower than the fuel pressure in the cam receiving chamber in the opening state of the control valve.

5. The high pressure fuel pump according to claim 1 , wherein the connection is located only on one axial side of the pressurizing chamber which is opposite to the plunger in an axial direction of the plunger.

6. A high pressure fuel pump for delivering fuel, which is suctioned into a pressurizing chamber from a low pressure fuel pump through a suction passage, to a supply destination after pressurizing the fuel in the pressurizing chamber with a plunger, the high pressure fuel pump comprising:
a pump body that slidably supports the plunger and forms the suction passage, the pressurizing chamber, a cam receiving chamber, a release passage, an internal pressure variable chamber and a communication passage, wherein the pressurizing chamber is communicated with the suction passage and the release passage through a connection, and the release passage is communicated with the cam receiving chamber which receives a drive cam that is configured to drive the plunger, and an internal pressure of the internal pressure variable chamber is increased and decreased in response to reciprocation of the plunger, and the communication passage communicates between the internal pressure variable chamber and the cam receiving chamber;
a control valve that is configured to open and close the connection; and
a controller that is configured to control an operation of the control valve, wherein:
the controller is configured to place the control valve in an opening state where the control valve opens the connection to supply the fuel from the suction passage to the pressurizing chamber through the connection in a suction stroke, during which the plunger is driven toward a suction side for suctioning the fuel into the pressurizing chamber;
the controller is configured to place the control valve in a closing state where the control valve closes the connection at a closing timing in a delivery stroke, during which the plunger is driven toward a delivery side for delivering the fuel out of the pressurizing chamber upon pressurization of the fuel after the suction stroke;
the controller is configured to maintain the control valve in the opening state to relieve the fuel, which is pressurized by the plunger, from the pressurizing chamber to the cam receiving chamber through the connection and the release passage during the delivery stroke until the closing timing reaches after a start of the delivery stroke;
the pump body forms a drain passage that drains the fuel from the cam receiving chamber to a fuel tank;
a passage cross-sectional area of a portion of the release passage is reduced on a side of the cam receiving chamber, at which the suction passage is placed, to form a release flow restricting portion; and
a passage cross-sectional area of at least-a portion of the drain passage is reduced in comparison to a passage cross-sectional area of the release flow restricting portion.

Assignees

• Denso Corp

Inventors

• Yamamoto Shuhei
• Onishi Kazuhiro

Classifications

• F02M59/34

  by throttling of passages to pumping elements or of overflow passages {, e.g. throttling by means of a pressure-controlled sliding valve having liquid stop or abutment} · CPC title

• F02M59/368 Primary

  Pump inlet valves being closed when actuated · CPC title

• F02M63/0265

  Pumps feeding common rails · CPC title

• F02M59/06 Primary

  with cylinders arranged radially to driving shaft, e.g. in V or star arrangement · CPC title

• F02M37/0047

  Layout or arrangement of systems for feeding fuel (fuel injection apparatus characterised by their conduits and venting means F02M55/00; fuel injection apparatus having a common rail F02M63/0225; arrangement of fuel conduits of low pressure fuel injection apparatus F02M69/462) · CPC title