JP2000097124A - High pressure fluid injection device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify the structure of a conduit line, and to prevent that the fuel is continued to inject in the disorder condition of a two-way valve for injection control, in a high pressure fluid injection device. SOLUTION: A needle 12 to open and close an injection hole 101 for fuel injection purpose is controlled by increasing and decreasing the pressure of a control hydraulic chamber 106 generating its back pressure. The high pressure fuel leading-in to the control hydraulic chamber 106, and the release of the high pressure, are carried out by a single common use conduit line 21, by switching a two-way valve 42. Inside a tubular body 11 is made into a valve chest 103 and a cylinder 105, and a needle 12 is held slidable in the cylinder 105 to prevent the leakage of the fuel from the sliding part of the needle 12 to the other part, so as to make a drain conduit line unnecessary. The leading-in of the high pressure fuel to the valve chest 103 is carried out through a check valve 14, and the fuel leading-in to the valve chest 103 is prohibited as well as the inside of the valve chest 103 is maintained at a high pressure, so as to prevent the continuous injection of the fuel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a high-pressure fluid ejection device.

[0002]

2. Description of the Related Art FIG. 2 shows a configuration of a high-pressure fluid injection device generally used in an internal combustion engine. The high-pressure fluid ejection device includes an injector 8 that ejects a high-pressure fluid from an injection hole.
1 and high-pressure line 8 connected to high-pressure reservoir 83
2, a low pressure line 84 and a drain line 87 connected to the low pressure reservoir 85 are provided. In the case of a common rail fuel injection device for a diesel internal combustion engine, the injector 81 is provided in each cylinder, the high-pressure reservoir 83 is a common rail common to each cylinder stored with high-pressure fuel, and the low-pressure reservoir 85 is a fuel tank. is there.

The injector 81 is connected to a high-pressure line 82 at a high-pressure port 81a of a body 810, and is connected to a low-pressure port 8a.
1b is connected to the low-pressure line 84 and the drain port 81
It is connected to the drain line 87 at c. Body 81
The valve chamber 811 and the spring chamber 81 are coaxial from the bottom to 0.
2. A cylinder 813 is formed. A high-pressure fluid is supplied to the valve chamber 811 from a high-pressure port 81a. Valve chamber 81
Numeral 1 communicates with the injection hole 815 via a passage 814, and the opening and closing of the injection hole 815 is performed by a needle 816 slidably held in a cylinder 813. The needle 816 has a valve body 8161 that is connected to the valve chamber 811 via the spring chamber 812.
And opens and closes the upstream end of the passage 814.

The driving force for driving the needle 816 to open and close is:
In the valve opening direction, the high-pressure fluid in the valve chamber 811 is applied to the valve body 816.
1 is acting on the tip surface. In the valve closing direction, the spring 817 provided in the spring chamber 812
6 are energized. Also, fluid is introduced from the high pressure port 81a into the control hydraulic chamber 819 via the inlet throttle 818,
This pressure acts on the upper end surface of the needle 816.

The opening and closing of the needle 816 is controlled by the control hydraulic chamber 81.
The change of the pressure is performed by a two-way valve 86 provided in the middle of the low-pressure line 84. That is, when the two-way valve 86 is "closed", the control hydraulic chamber 819 has a high pressure, and when it is "open", the control hydraulic chamber 819 is high.
Is released to the low-pressure reservoir 85 via the low-pressure line 84.

The spring chamber 812 has a valve chamber 81.
1. The fluid in the control hydraulic chamber 819 leaks through the sliding portion of the needle 816 and the like, and the leaked fluid returns to the low-pressure reservoir 85 through the drain port 81c and the drain pipe 87.

[0007] European Patent Application Publication No. EP 075365
In the fuel injection device for an internal combustion engine described in No. 9A1, the high pressure fluid from the high pressure port 81a is introduced into the valve chamber 811 through the spring chamber 812, thereby eliminating the need for the drain pipe 87.

[0008]

By the way, if the number of injectors is plural, the number of pipes is increased by the number, and the work of connecting these pipes to the high pressure port and the low pressure port of the injector is also increased. For example, a general internal combustion engine usually has four or more cylinders. Even in the case of the above-mentioned European Patent Application Publication No. EP0753659A1, since both the high-pressure pipe and the low-pressure pipe are essential, the routing of the pipes is complicated, and there is not much freedom in mounting.

Further, since the high-pressure fluid is constantly supplied from the high-pressure reservoir to the injector, if the two-way valve fails and remains "open", the high-pressure fluid is continuously injected.

The present invention has been made in view of the above circumstances,
It is an object of the present invention to provide a high-pressure fluid injection device that has a simple configuration of a pipeline and that can prevent continued injection of fuel even when a two-way valve for injection control fails.

[0011]

According to the first aspect of the present invention, the injector has a cylindrical body, and the inside of the body is formed as a valve chamber and a cylinder. A control hydraulic chamber that slidably holds the needle and opens and closes the injection hole, and communicates with a pipeline connecting the high-pressure reservoir and the injector to generate a back pressure of the needle that urges the needle in the valve closing direction. And an introduction path for guiding the high-pressure fluid from the pipe to the valve chamber, and a check valve provided in the middle of the introduction path and having a forward direction from the pipe toward the valve chamber. And, a throttle is provided in the middle of the pipeline, and a branch pipeline that branches from the pipeline to the low-pressure reservoir is provided downstream of the throttle, and in the middle of the branch pipeline,
A two-way valve is provided for switching between communication and shutoff between the pipe and the low-pressure reservoir and increasing or decreasing the pressure in the control hydraulic chamber to control the opening and closing of the needle.

When the line connecting the high pressure reservoir and the injector is disconnected from the low pressure reservoir, high pressure fluid is introduced into the control hydraulic chamber and the needle closes due to high back pressure. High-pressure fluid is also introduced into the valve chamber via a check valve. When the line communicates with the low-pressure reservoir, the pressure introduced into the injector decreases, but the pressure in the valve chamber is maintained at a high level because the check valve is closed. When the back pressure of the needle generated in the control hydraulic chamber is reduced due to the communication between the pipe and the low-pressure reservoir and the needle is opened, the fuel in the valve chamber is injected from the injection hole.

As described above, high pressure fluid can be introduced into the valve chamber and the control hydraulic chamber using the section of one pipe from the branch to the branch pipe to the injector. The high pressure in the hydraulic chamber can be released to the low pressure reservoir. In addition, since the body is cylindrical and the inside of the body is a valve chamber and a cylinder, the fluid in the valve chamber and the control hydraulic chamber does not leak to other places through the gap between the cylinder wall and the needle, and the drain pipe is unnecessary. It is. Therefore, it is only necessary to connect one pipe in the injector, and the configuration of the pipe can be simplified. That is,
It is easy to route pipes and easy to install.

When the two-way valve is opened to communicate between the control hydraulic chamber and the low-pressure reservoir, the pressure introduced into the injector becomes low as described above, and the check valve is closed. Therefore, as long as the two-way valve is "open", no high-pressure fluid is introduced into the valve chamber. Therefore, even when the two-way valve is left open due to failure,
The high pressure fluid does not continue to be injected from the injection hole.

[0015]

FIG. 1 shows a configuration of a high-pressure fluid ejection device according to the present invention. Description will be made assuming that the invention is applied to fuel injection. The high-pressure fluid injection device includes an injector 1 for injecting fuel, a high-pressure reservoir 3 for holding high-pressure fuel as a high-pressure fluid, a low-pressure reservoir 6 for holding low-pressure fuel as a low-pressure fluid,
It is composed of a main pipe 2 as a pipe through which fuel flows, a branch pipe 5, a control actuator 4 for injection control, and the like.

The injector 1 has a cylindrical body 11 and is mounted so as to penetrate the combustion chamber wall. An injection hole 101 for fuel injection is formed at the lower end of the body 11, and only one fuel port 15 for connecting to the main conduit 2 is provided at the upper end. The lower side of the body 11 is the valve chamber 103.
And the upper side is the cylinder 105. Valve room 1
The needle 12 is provided through the cylinder 03 and the cylinder 105.

The valve chamber 103 has a stepped shape in which the upper half has a large diameter and the lower half has a small diameter. On the lower wall surface of the valve chamber 103, a passage 102 communicating with the injection hole 101 is opened at the position of the axis C. Fuel is introduced into the valve chamber 103 through an introduction passage 104 having the fuel port 15 as an upstream end. A check valve 14 having a forward direction from the fuel port 15 to the valve chamber 103 is provided in the middle of the introduction path 104, and allows the fuel to flow only in the above-described direction.

The cylinder 105 has a smaller diameter than the large diameter half of the valve chamber 103.
Are slidably held, and a piston portion 122, which is an upper portion of the needle 12, is in sliding contact with the wall surface of the cylinder 105.

The diameter of the needle 12 is slightly smaller than the lower half of the valve chamber 103 and larger than the upstream end of the passage 102. The distal end surface 12a of the valve body 121 is formed in a conical shape, and the needle 12 is seated on the periphery of the upstream end of the passage 102 as a valve seat 102a, and the valve chamber 103 and the passage 102
Between the two.

When the needle 12 is closed, hydraulic pressure acts on the distal end surface 102a of the annular portion above the contact portion with the valve seat 102a, except for the pointed portion, by the fuel in the valve chamber 103. When the valve is opened, hydraulic pressure acts on the entire distal end surface 102a. The hydraulic pressure acting on the distal end surface 102a urges the needle 12 upward, that is, in the valve opening direction.

A large-diameter half of the valve chamber 103 is a spring chamber 1031, and a coil-shaped spring 13 is provided on the outer periphery of the needle 12. The spring 13
A flange 123 formed on the peripheral wall surface of the needle 12 and the valve chamber 1
03 is held in a compressed state between the upper wall surfaces of the needle 1
2 is urged downward, that is, in the valve closing direction.

A space is defined above the needle 12 and between the wall of the cylinder 105 and the control hydraulic chamber 10.
There are six. The control hydraulic chamber 106 communicates with the fuel port 15, and a control hydraulic pressure is introduced into the control hydraulic chamber 106. This control oil pressure acts on the upper end surface of the needle 12 to generate a back pressure that urges the needle 12 downward, that is, in the valve closing direction.

The main line 2 has one end connected to the injector 1 at the fuel port 15 and the other end connected to the high-pressure reservoir 3.

The control actuator 4 is provided in the middle of the main line 2 and controls the pressure of the fuel introduced into the injector 1.
The control actuator 4 is provided with an inlet orifice 41 that is constricted in the middle of the trunk line 2, and a branch line 5 that branches off from the main line 2 at a downstream portion 2 a thereof. The branch line 5 is connected to a low-pressure reservoir 6.

An electromagnetic two-way valve 42, which is a two-way valve, is provided in the middle of the branch pipe line 5.
An outlet orifice 43 is provided on the a side. Electromagnetic two-way valve 4
Reference numeral 2 indicates that the control hydraulic chamber 106 communicates with the low-pressure reservoir 6 via the outlet orifice 43 when the valve is "open", and shuts off the control hydraulic chamber 106 and the low-pressure reservoir 6 when the valve is "closed". An “open” command is output to the electromagnetic two-way valve 42 from a not-shown electronic control unit (ECU) at a predetermined time for a predetermined time.

In the middle of the main line 2, a check valve 7 is provided between the high-pressure reservoir 3 and the control actuator 4 so that the direction from the high-pressure reservoir 3 toward the control actuator 4 is a forward direction. The effect of pressure pulsation 3 is shielded.

When there are a plurality of injectors 1, the high-pressure reservoir 3 and the low-pressure reservoir 6 are common, and in the case of a common rail type fuel injection device, the high-pressure reservoir 3 is a common rail and the low-pressure reservoir 6 is a fuel tank.

The operation of the high-pressure fluid ejection device will be described. First, when the device is started, when the electromagnetic two-way valve 42 is closed, the connection between the main line 2 and the low-pressure reservoir 6 is shut off, and high-pressure fuel is introduced from the high-pressure reservoir 3 to the injector 1 via the main line 2. The introduced high-pressure fuel causes the pressure in the control hydraulic chamber 106 to increase, while the check valve 14 opens, and the introduction path 10
4, the valve chamber 103 is filled. After filling the valve chamber 103 with high-pressure fuel, the check valve 14 closes again.

In this state, when the electromagnetic two-way valve 42 is opened in response to the "open" command from the ECU, the main pipeline 2
And the low-pressure reservoir 6 communicate with each other, and the main line 2 is throttled by the inlet orifice 41 upstream of the branch portion 2a, so that the high pressure of the control hydraulic chamber 106 is reduced by the branch portion 2a of the main line 2. A section (hereinafter, a dual-purpose pipe line) 21 from the to the connection end to the fuel port 15 is opened to the low-pressure reservoir 6 through the branch pipe line 5, and the urging force of the needle 12 in the valve closing direction decreases. On the other hand, in the valve chamber 103, since the check valve 14 keeps the closed state and the space between the valve chamber 103 and the fuel port 15 is shut off,
The pressure remains high.

The pressure reduction width of the control hydraulic chamber 106 is given by the ratio of the opening area of the inlet orifice 41 to the opening area of the outlet orifice 43.
When the urging force in the valve opening direction and the urging force in the valve closing direction fall below a balanced pressure, the needle 12 lifts, and the valve chamber 103
The high-pressure fuel inside is injected from the injection hole 101.

When the electromagnetic two-way valve 42 is closed in response to the "open" command from the ECU, the main line 2 and the low-pressure reservoir 6 are shut off again, and the pressure of the fuel introduced into the injector 1 increases. High-pressure fuel is introduced from the fuel port 15. As a result, the pressure in the control hydraulic chamber 106 is reduced to the inlet orifice 41.
Then, the urging force in the valve closing direction with respect to the needle 12 increases at a speed corresponding to the opening area of the needle 12, and finally the urging force in the valve closing direction becomes dominant, and the needle 12 closes. On the other hand, the valve chamber 10
In No. 3, the pressure is reduced by the fuel injection. Then, the check valve 14 is opened, high-pressure fuel is introduced into the valve chamber 103, and the high-pressure fuel is again charged into the valve chamber 103 to prepare for the next fuel injection.

As described above, the introduction of the high-pressure fuel into the valve chamber 103 and the control hydraulic chamber 106 and the opening of the control hydraulic chamber 106 to the high-pressure low-pressure reservoir 6 require only one shared pipe connected to the injector 1. This is done by way 21.

The body 11 is formed into a cylindrical shape.
The inside of the valve chamber 103 and the cylinder 105 is used for the fuel in the valve chamber 103 and the control hydraulic chamber 106.
It does not leak to other places through the gap between the wall and the needle 12. Of the fuel introduced into the injector 1, the fuel introduced into the valve chamber 103 is injected from the injection hole 101,
The fuel introduced into the control hydraulic chamber 106 is returned to the low-pressure reservoir 6 via the shared pipeline 21. That is, a drain pipe (see FIG. 2) is unnecessary, and a leakless structure is provided.

Therefore, in the injector 1, only one dual-purpose pipe 21 needs to be connected to one fuel port 15, and the configuration of the pipe can be simplified as shown in the figure. In other words, the arrangement of the pipeline is simple and the mounting property is good.

Further, the high-pressure fluid ejection device of the present invention has the following effects. When the electromagnetic two-way valve 42 is set to “open”, the fuel pressure introduced into the injector 1 becomes low as described above, and the check valve 14 is set to the “closed” state. , No high-pressure fuel is introduced into the valve chamber 103. Therefore, even when the electromagnetic two-way valve 42 is closed due to a failure due to a failure of the ECU in response to a “close” command from the ECU, fuel is not continuously injected from the injection hole 101.

In addition, after the electromagnetic two-way valve 42 is opened, the pressure in the valve chamber 103 acting on the distal end surface 12a of the needle 12 in the valve opening direction is reduced by fuel injection. The force becomes inferior to the urging force in the valve closing direction, which is composed of the pressure of the control hydraulic chamber 106 and the spring force of the spring 13, and the needle 12 closes quickly.

The outlet orifice may be shared by the electromagnetic two-way valve 42.

The present invention can be applied to an injector in which a spring is provided in a control hydraulic chamber. Also,
Although the present embodiment has been described for fuel injection, the present invention can also be applied to injection of other high-pressure fluid.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of a high-pressure fluid ejection device of the present invention.

FIG. 2 is a cross-sectional view illustrating an example of a conventional high-pressure fluid ejection device.

[Explanation of symbols]

 Reference Signs List 1 injector 11 body 12 needle 14 check valve 101 injection hole 103 valve chamber 104 introduction path 105 cylinder 106 control hydraulic chamber 2 main pipe (pipe) 2a branch section 21 dual-use pipe 3 high-pressure reservoir 4 control actuator 41 inlet orifice Throttle) 42 electromagnetic two-way valve (two-way valve) 43 outlet orifice 5 branch pipe (pipe) 6 low-pressure reservoir

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yoshihiro Tsuzuki 14 Iwatani, Shimowakaku-cho, Nishio-shi, Aichi Japan Inside the Japan Automotive Parts Research Institute (72) Inventor Toshihiko Inoka 1-chome, Showa-cho, Kariya-shi, Aichi Address DENSO Corporation (72) Inventor Showa Kojima 1-1-1, Showa-cho, Kariya-shi, Aichi F-term (reference) 3G066 AA07 AB02 AC09 AD12 BA12 BA30 BA33 CB07U CB09 CB11 CB12 CC06T CC08T CC14 CC21 CC63 CC64T CC66 CC69

Claims (1)

[Claims] 1. An injector for injecting a high-pressure fluid from an injection hole, a high-pressure reservoir holding a high-pressure fluid, a low-pressure reservoir holding a low-pressure fluid, and a high-pressure reservoir and a pipe connecting the low-pressure reservoir and the injector. In the high-pressure fluid ejection device provided, the injector has a cylindrical body, the body is formed into a valve chamber and a cylinder, and the injector is provided through the valve chamber and the cylinder, and is slidably held in the cylinder. A control hydraulic chamber that opens and closes the injection hole, communicates with a pipeline connecting the high-pressure reservoir and the injector, and generates a back pressure of the needle that urges the needle in the valve closing direction; An introduction path that guides fluid to the valve chamber, and a check valve that is provided in the middle of the introduction path and has a forward direction in which a direction from the pipe line toward the valve chamber is a forward direction.
In addition, a throttle is provided in the middle of the pipeline, and a branch pipeline branching from the pipeline and reaching the low-pressure reservoir is provided downstream of the throttle, and communication and blocking between the pipeline and the low-pressure reservoir is provided in the middle of the branch pipeline. A high-pressure fluid injection device, comprising a two-way valve for controlling the opening and closing of the needle by increasing and decreasing the pressure of the control hydraulic chamber.