Injector

Patent metadata

Field	Value
Publication number	US-10156216-B2
Application number	US-201615738692-A
Country	US
Kind code	B2
Filing date	Jun 2, 2016
Priority date	Jun 26, 2015
Publication date	Dec 18, 2018
Grant date	Dec 18, 2018

Abstract

An enclosure member includes a throughhole that penetrates a cover portion. The cover portion includes a blocking portion that receives an abutment by a wall portion to close an opening of an outflow passage with respect to spaces outside of the enclosure member. The blocking portion is provided so as to surround an opening of the throughhole, and the throughhole is in communication with the outflow passage even when the blocking portion is abutting the wall portion. Further, a spring is outside of a back pressure chamber to bias the enclosure member. The enclosure member itself blocks outside spaces from the back pressure chamber, so the expenditure of high pressure fuel may be controlled, and an injection hole may be opened and closed by a needle.

First claim

The invention claimed is:

1. An injector, comprising:
a needle which is a valve body configured to open and close an injection hole that injects fuel;
a body which has a cylindrical shape and which houses the needle therein, the body having the injection hole;
a back pressure chamber for exerting a back pressure of fuel on the needle in a direction of closing the injection hole;
an outflow passage that allows fuel to flow out of the back pressure chamber;
a drive unit configured to open and close the outflow passage based on a control signal from a controller, thereby increasing or decreasing the back pressure to operate the opening and closing of the injection hole via the needle;
an enclosure member that includes
a cover portion configured to cover a rear end of the needle from a rear side, and
a cylinder portion configured to be in slidable contact with an outer circumferential surface of the needle to slidably support the needle, the rear end of the needle being surrounded by the cover portion and the cylinder portion to form the back pressure chamber on a rear end side of the needle;

a spring configured to bias the enclosure member toward the rear side; and
a wall portion disposed on the rear side of the cover portion and configured to receive an abutment of the cover portion to regulate movement of the enclosure member toward the rear side, the wall portion including an opening of the outflow passage, wherein
the enclosure member includes at least one throughhole that penetrates through the cover portion,
the cover portion includes a blocking portion that, when the cover portion abuts the wall portion, blocks the opening of the outflow passage with respect to spaces outside of the enclosure member,
the blocking portion is provided so as to surround an opening of the throughhole, the throughhole being in communication with the outflow passage even when abutting the cover portion, and
the spring is outside of the back pressure chamber to bias the enclosure member.

2. An injector, comprising:
a needle which is a valve body configured to open and close an injection hole that injects fuel;
a body which has a cylindrical shape and which houses the needle therein, the body having the injection hole;
a back pressure chamber for exerting a back pressure of fuel on the needle in a direction of closing the injection hole;
an outflow passage that allows fuel to flow out of the back pressure chamber;
a drive unit configured to increase or decrease the back pressure based on a control signal from a controller to operate the opening and closing of the injection hole via the needle, the drive unit including a three way valve that switches the outflow passage between two connections, the outflow passage being connected to one connection when the back pressure is to be decreased, the outflow passage being connect to another connection when the back pressure is to be increased;
an enclosure member that includes
a cover portion configured to cover a rear end of the needle from a rear side, and
a cylinder portion configured to be in slidable contact with an outer circumferential surface of the needle to slidably support the needle, the rear end of the needle being surrounded by the cover portion and the cylinder portion to form the back pressure chamber on a rear end side of the needle;

a spring configured to bias the enclosure member toward the rear side; and
a wall portion disposed on the rear side of the cover portion and configured to receive an abutment of the cover portion to regulate movement of the enclosure member toward the rear side, the wall portion including an opening of the outflow passage, wherein
the enclosure member includes at least one throughhole that penetrates through the cover portion,
the cover portion includes a blocking portion that, when the cover portion abuts the wall portion, blocks the opening of the outflow passage with respect to spaces outside of the enclosure member,
the blocking portion is provided so as to surround an opening of the throughhole, the throughhole being in communication with the outflow passage even when abutting the cover portion, and
the spring is outside of the back pressure chamber to bias the enclosure member.

3. The injector of claim 1 , wherein
the spring is set so as to bias the enclosure member toward the rear side and also to bias the needle toward a leading side, and
the needle is moved toward the leading side by the biasing force of the spring and the back pressure.

4. The injector of claim 1 , wherein
an abrasion resistance treatment is performed on the blocking portion and the wall portion.

5. The injector of claim 2 , wherein
the spring is set so as to bias the enclosure member toward the rear side and also to bias the needle toward a leading side, and
the needle is moved toward the leading side by the biasing force of the spring and the back pressure.

6. The injector of claim 2 , wherein
an abrasion resistance treatment is performed on the blocking portion and the wall portion.

Assignees

• Denso Corp

Inventors

• Tanada Hiroki
• Ueda Daiji

Classifications

• F02M47/00

  Fuel-injection apparatus operated cyclically with fuel-injection valves actuated by fluid pressure (fuel- injectors actuated by the pressure in engine working cylinders F02M49/00) · CPC title

• F02M55/008

  Arrangement of fuel passages inside of injectors · CPC title

• F02M2547/008

  Means for influencing the flow rate out of or into a control chamber, e.g. depending on the position of the needle · CPC title

• F02M47/027 Primary

  Electrically actuated valves draining the chamber to release the closing pressure · CPC title

• F02M47/02 Primary

  of accumulator-injector type, i.e. having fuel pressure of accumulator tending to open, and fuel pressure in other chamber tending to close, injection valves and having means for periodically releasing that closing pressure · CPC title