JPH03121254A - Fuel injector - Google Patents

Abstract

PURPOSE:To prevent bites between the nozzle for foreign material and a needle valve by providing a fuel filter for preventing the intrusion of foreign material from the upstream side on the supply port side of a fuel passage, and disposing a check valve for preventing the intrusion of foreign material from the downstream side on the exhaust port side of the fuel passage. CONSTITUTION:The fuel of the specified pressure from a fuel pump flows into a fuel passage 33 through a fuel supply piping 15, then an anchor 10 is sucked against a spring 11 by applying a current to the electromagnetic coil 7C of an electromagnetic actuator 7 so as to displace a needle valve 9 slidingly to be opened, and thus an injector performs fuel injection from a nozzle 8C. In this case, a fuel filter 16 is disposed at the supply port 33A1 of the fuel passage 33. An enlarged diameter part 31D1 is provided at the through passage 31E, connected to a fuel exhaust piping 17 communicated with the fuel passage 33, of a fixed iron core, and a check valve 34 for impeding the passage of fuel from the downstream side is disposed at this enlarged diameter part 31D1, thus preventing the intrusion of foreign material from the downstream side.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a fuel injector used, for example, in an electronically controlled fuel injection device.

[Conventional technology]

As a conventional fuel injector, one shown in FIG. 2 is known.

In the figure, 1 is installed on the intake passage side of the engine,
The injector body (hereinafter referred to as
The main body 1 has a generally cylindrical shape as a whole, and has a small-diameter nozzle mounting portion 2 formed at its distal end (lower end in the figure) and a base end (upper end in the figure). A communication hole 4 is formed in the peripheral wall of the main body 1 to supply fuel from the outside into the main body 1. A fuel inlet 5 is provided.

A fixed iron core 6 is made of a metal material or the like and extends to the center of the actuator accommodating part 3, and the fixed iron core 6 includes an iron core part 6A into which a coil bobbin 7B, which will be described later, is inserted;
A flange portion 6B is located above the iron core portion 6A and is formed into a brim shape, and its peripheral edge is caulked and fixed to the upper end of the actuator housing portion 3 to close the inside of the actuator housing portion 3; It is composed of a caulking part 6C located on the upper side and fixedly supporting the adjustment vibrator 12 described below, and a piping connection part 6D located on the upper side of the caulking part 6C and connected to the fuel discharge piping 17 described below. A through passage 6E is provided that penetrates upward and downward from the section 6A to the piping connection section 6D.

Reference numeral 7 denotes an electromagnetic actuator housed in the actuator housing part 3. The electromagnetic actuator 7 includes a core member 7A formed with an iron core part 6A extending inside the actuator housing part 3, and a core member 7A formed with an iron core part 6A extending inside the actuator housing part 3. Coil bobbin 7B positioned and inserted into the outer periphery of the core member 7A
and an electromagnetic coil 7C wound around the outer periphery of the coil bobbin 7B.

8 is a nozzle body that is fitted and fixed to the nozzle mounting part 2;
The nozzle body 8 has a generally cylindrical shape as a whole, into which a needle valve 9 (described later) is slidably fitted, and an internal passage 8A serving as a fuel passage, and a tip end of the internal passage 8A. It has a valve seat 8B formed inside and an injection port 8C formed below the valve seat 8B.

9 is inserted into the internal passage 8A of the nozzle body 8,
A needle valve is provided to be slidable in the axial direction.The upper end of the needle valve 9 becomes an anchor fixing part 9A that is integrally fixed with an anchor 10, which will be described later, and the lower end is attached to a valve seat 8B of the nozzle body 8. This is a valve portion 9B that applies separation pressure. A plurality of chamfered portions 9C for forming fuel passages between the anchor fixing portion 9A and the anchor 10 are formed on the outer peripheral surface of the anchor fixing portion 9A.

10 is an anchor that is slidably inserted into the communication hole 4 while being fixed to the anchor fixing part 9A of the needle valve 9;
The anchor 10 is provided with a through hole 10A in the upper and lower directions, and an anchor fixing portion 9A is provided below the through hole 10A.
An enlarged diameter portion 10B is formed to fit and fix the. Fuel can flow between the anchor fixing part 9A and the enlarged diameter part 10B at the chamfered part 9C of the anchor fixing part 9A. Furthermore, on the upper peripheral wall of the anchor 10,
It has a lateral hole 10C drilled in the radial direction so that fuel from the large fuel flow port 5 can be introduced into the through hole 10A.

Reference numeral 11 denotes a spring inserted into the lower part of the through passage 6E of the fixed iron core 6, and the spring 11 comes into contact with the upper surface of the anchor 10 to urge the anchor 10 downward. 1
Reference numeral 2 denotes a sleeve-shaped adjustment vibrator that is inserted into the through passage 6E of the fixed iron core 6 and supports the upper end of the spring 11. The adjustment vibe 12 is positioned at an appropriate position within the through passage 6E, and is inserted into the through passage 6E of the fixed iron core 6. By caulking and fixing, the biasing force of the spring 11 is adjusted.

Reference numeral 13 denotes an L-shaped fuel supply pipe integrally attached to the main body 1 in communication with the fuel inlet 5 so as to constitute a casing together with the main body 1; It is composed of a communication pipe 13A directly attached to the communication pipe 13A, and a connecting pipe 13B that is integrally attached to the communication pipe 13A and connected to a fuel supply pipe 15, which will be described later, and has a supply passage 13G inside.

The fuel passage 14 is constituted by the supply passage 13C, the fuel inlet 5, the horizontal hole 10C, the through hole 10A, and the through passage 6E along the flow of fuel, and includes the horizontal hole 1oC and the through hole 10.
The upstream side of the anchor 10 having A is the supply passage section 1.
4A, the downstream side is the discharge passage section 14B.

A fuel supply pipe 15 connects a fuel pump (not shown) and the connecting pipe 13B, and the fuel supply pipe 15 introduces fuel in a fuel tank (not shown) to the supply passage section 14A. Reference numeral 16 denotes a fuel filter provided at the supply port 14A of the supply passage portion 14A, and the fuel filter 16 filters foreign matter flowing from the fuel supply pipe 15 side and prevents the foreign matter from entering the fuel passage 14 side. is prevented.

Reference numeral 17 denotes a fuel discharge pipe that connects the pipe connection part 6D of the fixed iron core 6 and the fuel tank via a pressure regulator (not shown), and the fuel discharge pipe 17 is discharged to the outside via the discharge passage part 14B. Fuel is returned to the fuel tank.

Reference numeral 18 denotes a discharge passage section 14 which is an outlet section of the piping connection section 6D.
The fuel filter 18 is a fuel filter provided at the exhaust port 14B1 of the fuel outlet 14B, and the fuel filter 18 prevents foreign matter from flowing toward the fuel passage 14 due to backflow of fuel from the fuel exhaust pipe 17 side or due to precipitation when the flow of fuel is stopped. Preventing intrusion.

19 is a stopper that regulates the lift amount of the needle valve 9; 20 is a nozzle holder that protects the injection port 8C; and 21 is a stopper that is electrically connected to the electromagnetic coil 7C to supply power. Connector provided.

The conventional fuel injector is configured as described above, but the fuel from the fuel pump flows into the fuel passage 14 from the supply port 14A1 via the fuel supply pipe 15 while maintaining a predetermined pressure, and the fuel is When passing through the passage 14, the electromagnetic coil 7C is cooled, and the fuel is returned to the fuel tank via the fuel discharge pipe 17. Furthermore, when passing through the fuel passage 14, the fuel that has flowed into the through hole 10A from the supply passage part 14A via the side hole 10C flows to the discharge passage part 4B, and also flows between the chamfered part 9C of the anchor fixing part 9A and the anchor 10. The fuel is supplied to the injection port 8C through the internal passage 8A of the nozzle body 8 while maintaining a predetermined pressure.

When an injection pulse from a control device (not shown) electrically connected via the connector 21 is supplied to the electromagnetic coil 7C of the electromagnetic actuator 7, a magnetic path is formed in the core member 7A, and the anchor 10 is attracted against the urging force of the spring 11, so that the needle valve 9 is slid and opened, and fuel is injected outward from the injection port 8C.

[Problem to be solved by the invention]

By the way, in the above-mentioned conventional technology, the supply passage section 1
Fuel filters 16.18 are provided at the supply port 14A1 of the fuel injector 14A and the discharge port 14B of the discharge passage section 14B, but when the fuel injector is assembled, foreign matter such as dust and cutting powder remains in the fuel passage 14. 2
If two fuel filters 16, 18 are installed, foreign particles will have no place to escape and will float in the fuel passage 14.

Furthermore, if the fuel filter 16 on the supply passage section 14A side is damaged, foreign matter from the upstream side passes through the damaged fuel filter 16, enters the fuel passage 14, and becomes floating.

Foreign matter in the fuel passage 14 may flow into the injection port 8C together with the fuel when the needle valve 90 is opened, and may become caught between the valve seat 8B and the valve portion 9B. However, there is a problem in that the valve seat 8B and the valve portion 9B cannot be brought into close contact with each other (this results in fuel leaking from the injection port 8C).

The present invention was made in view of the problems of the prior art described above, and an object of the present invention is to provide a fuel injector that can reliably eliminate the problem caused by floating foreign objects.

[Means to solve the problem]

The configuration adopted by the present invention in order to solve the above-mentioned problems includes a casing containing an actuator, a fuel passage formed within the casing, with one end serving as a supply port and the other end serving as a discharge port, and the casing. a nozzle body that is provided in the nozzle body and has an injection port on the tip side to which fuel is supplied from the fuel passage; In a fuel injector equipped with a needle valve that opens and closes, a fuel filter is provided on the supply port side of the fuel passage to prevent foreign matter from entering from the upstream side, and a fuel filter is provided on the discharge port side of the fuel passage to prevent foreign matter from entering from the upstream side. It is equipped with a check valve that allows circulation and passage of foreign matter and prevents foreign matter from entering from the downstream side.

[Function] With the above configuration, when foreign matter remains in the fuel passage, the check valve is activated when fuel is supplied from the supply port into the fuel passage, passes through the passage, and is discharged to the outside from the discharge port. When the valve is opened, the foreign matter passes through the opened check valve together with the fuel and flows out to the outside.

Also, when the fuel supply stops, the check valve closes.
Prevents foreign matter from entering from the downstream side of the fuel passage.

〔Example〕

Embodiments of the present invention will be described below with reference to FIG. The overall configuration of the fuel injector of this example is as follows:
Fixed iron core 6 and discharge passage section 14B of the prior art described above
Since they are the same except for the fuel filter 18 provided at the discharge port 14B+, the same members are given the same reference numerals and their explanations will be omitted here.

In the figure, 31 is the fixed iron core of this embodiment, and the overall structure of the fixed iron core 31 is almost the same as that of the fixed iron core 6 of the conventional technology, including an iron core portion 31A formed above the iron core portion 31A. flange portion 31B, a caulking portion 31C located above the flange portion 31B, a piping connection portion 31D located above the caulking portion 31G and connected to the fuel discharge pipe 17, etc. Penetration passage 31 to piping connection 31D
E is provided. The through passage 31E is formed with an enlarged diameter at the piping connection portion 31D, and a stepped portion at the boundary between the enlarged diameter portion 31D and other portions forms the valve seat 32 of the valve body 35, which will be described later. It becomes. Note that the fuel passage 33 of this embodiment includes a supply passage 13C1, a fuel inlet 5, and a side hole 10.
It is composed of a C1 through hole 10A and a through passage 31E, and the upstream side of the anchor 10 is a supply passage part 33A, and the downstream side is a discharge passage part 33B.

Reference numeral 34 designates a check valve of this embodiment, and the check valve 34 is located at the enlarged diameter portion 31D of the through passage 31E, and includes a valve body 35 that contacts the valve seat 32 to open and close the through passage 31E; A spring 36 that biases the valve body 35 toward the valve seat 32 is embedded in the inner wall surface of the enlarged diameter portion 31D, and the spring 36 is embedded in the inner wall surface of the enlarged diameter portion 31D.
6 and an annular spring receiver 37 that supports the upper end of the spring.

In the fuel injector of this embodiment configured as described above, as in the prior art, fuel is supplied from the fuel pump to the fuel passage from the supply port 33A through the fuel supply pipe 15 while maintaining a predetermined pressure. 33, cools the electromagnetic coil 7C, and is returned to the fuel tank via the fuel discharge pipe 17.

Furthermore, the fuel that has flowed into the through hole IOA is
3B, and is also supplied to the injection port 8C while maintaining a predetermined pressure. Then, the anchor 10 is attracted by the electromagnetic actuator 7 against the biasing force of the spring 11, the needle valve 9 is opened, and fuel is injected outward from the injection port 8C.

On the other hand, if foreign matter is mixed into the fuel when the fuel is returned from the fuel supply pipe 15 to the fuel tank via the fuel passage 33 and the fuel discharge pipe 17, the foreign matter will be captured by the fuel filter 16.

In addition, when assembling the fuel injector, it is sometimes necessary to install the fuel injector when there is a foreign object remaining in the fuel passage 33, or when the fuel filter 16 is damaged and a foreign object enters the fuel passage 33 together with the fuel from the upstream side. Fuel discharge pipe 17
The fuel flows out into the fuel discharge pipe 17 along with the fuel via the check valve 34, which opens as the fuel flows out. Then, when the flow of fuel stops, the check valve 34 closes,
Backflow of fuel from the fuel discharge pipe 17 into the fuel passage 33 is prevented, and foreign matter present on the fuel discharge pipe 17 side is prevented from entering the fuel passage 33.

As a result, foreign matter remains in the fuel passage 33 and the valve seat 8B
and the valve part 9B, and the injection port 8
It is possible to reliably prevent fuel from leaking from C.

In addition, when the flow of fuel is stopped, the check valve 34
The valve is closed and backflow is suppressed, and foreign matter present in the fuel discharge pipe 17 can be reliably prevented from entering the fuel passage 33.

In addition, in this embodiment, the check valve 34 is connected to the discharge passage section 33.
The check valve 34 is provided at the discharge port 33B1 of the anchor 10 to prevent foreign matter from entering the internal passage 8A of the nozzle body 8 from the fuel passage 33.
Since it is possible to prevent foreign matter from entering the internal passage 8A, it may be provided at any position within the discharge passage section 33B or the fuel discharge pipe 17 as long as it is on the downstream side of the boundary. However, when installed in the fuel discharge pipe 17, the mounting position is the pipe connection part 31.
Desirably around D.

Further, in this embodiment, the check valve 34 is composed of the valve body 35, the spring 36, and the spring receiver 37, but the present invention is not limited to this, and the present invention is not limited to this, and the check valve 34 has other structures such as those using a plate-shaped valve body. But that's fine.

〔Effect of the invention〕

As detailed above, according to the present invention, a fuel filter is provided on the supply port side of the fuel passage to prevent foreign matter from entering from the upstream side, and a fuel filter is provided on the discharge port side of the fuel passage to allow passage of foreign matter from the upstream side. At the same time, since a check valve is provided to prevent foreign matter from entering from the downstream side, foreign matter remaining in the fuel passage is discharged to the outside through the check valve along with the flow of fuel, and the foreign matter is removed from the injection port of the nozzle body and the injection port. This eliminates the possibility of getting caught between the needle valve that opens and closes the mouth, and it is possible to reliably prevent fuel from leaking from the injection port.

In addition, when the flow of fuel is stopped, the check valve closes to prevent backflow of fuel, thereby reliably preventing foreign matter present on the downstream side of the fuel passage from entering the fuel passage. .

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a fuel injector according to an embodiment of the present invention, and FIG. 2 is a vertical cross-sectional view showing a fuel injector according to a prior art. 1... Injector body (casing), 7... Electromagnetic actuator, 8... Nozzle body, 8C...
Injection port, 9... Needle valve, 13... Fuel supply piping (casing), 16... Fuel filter, 33...
Fuel passage, 33A,... Supply port, 33B,... Discharge port, 34... Check valve.

Claims (1)

[Claims] A casing containing an actuator; a fuel passage formed within the casing, with one end serving as a supply port and the other end serving as a discharge port; and a fuel passage provided in the casing and having a distal end supplied with fuel from the fuel passage. In the fuel injector, the fuel injector includes a nozzle body having an injection port, and a needle valve that is slidably inserted into the nozzle body and opens and closes the injection port of the nozzle body under control of the actuator. A fuel filter is provided on the inlet side to prevent foreign matter from entering from the upstream side, and a fuel filter is provided at the outlet side of the fuel passage to allow the flow of fuel from the upstream side and the passage of foreign matter, and to prevent the intrusion of foreign matter from the downstream side. A fuel injector characterized by being equipped with a check valve that prevents