JP2003120459A - Injection valve for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To completely avoid breakage and cracking by preventing high tensile strength in a range in which an inflow hole and an internal cut cross each other. SOLUTION: This injection valve, used for an internal combustion engine, is provided with a valve casing section 4 including the internal cut 20 having a roughly circular cross section and the inflow hole 16 for compressed fuel which opens inside the internal cut 20, whereas the inflow hole 16 is formed so as to cross the internal cut 20 of a valve casing section by part 45 of an internal cross section 44.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an injection valve for an internal combustion engine, particularly an injection valve for a common rail fuel injection system,
A type of valve casing having an internal cutout having a substantially circular cross section and an inlet hole for high pressure fuel opening into the internal cutout.

[0002]

2. Description of the Prior Art An injection valve of this type is known from DE-A-1983 2826. This known injection valve is used in a common rail injection device for an internal combustion engine, which is designed as an injector and has a fuel high pressure accumulator which is connected to a high pressure pump. The injection valve has a fuel high pressure connection connected to the fuel high pressure accumulator, a fuel low pressure connection for connection to the fuel return device, and an electrical connection. Serves to electrically control the electrically operated control valve of the injection valve, which is, for example, a solenoid valve. In the known injection valve, the valve needle is loaded in the closing direction by the fuel pressure in the control pressure chamber via the valve piston. The control pressure chamber is arranged in a valve member inserted in the valve casing and is connected to the fuel high pressure connection or to the fuel low pressure connection via a supply passage with a supply throttle and a discharge passage with a discharge throttle. Connected to the department.
The discharge passage can be opened and closed by means of a valve component of the control valve, which has, for example, an electromagnetic regulator or a piezoelectric regulator as a drive, and the fuel pressure in the control pressure chamber can be controlled by the individual actuation of the valve needle. Can be controlled for the process. The opening speed of the valve needle is defined by the flow-through difference between the supply throttle and the discharge throttle when the discharge passage is opened, and thus by the fixedly adjusted dimensional ratio of the supply throttle and the discharge throttle.

In the known injection valve, the supply passage for the high-pressure fuel is made up of several parts and has an inlet hole provided in the valve casing part of the injection valve, which inlet hole is the valve casing. An inner notch of the portion opens into a ring chamber surrounding the valve member. The inflow hole in this case is open in its internal cutout over its entire internal cross section. In practice, we know the following: That is, in the known injection valve, in the intersection region of the inflow hole and the internal cutout, strong tensile stress is generated in the circumferential direction based on the inflow hole cutout effect and high fuel pressure. , Damage or crack formation may occur.

[0004]

[Patent Document 1] German Patent Publication No. 19832
No. 826

[0005]

SUMMARY OF THE INVENTION The object of the present invention is therefore to improve an injection valve of the type mentioned at the outset to generate a strong tensile stress in the region of intersection of the inlet hole and the internal notch,
As a result, it is to provide an injection valve capable of reliably avoiding damage or crack formation in the region.

[0006]

In order to solve this problem, in the structure of the present invention, the inflow hole intersects with the internal cutout of the valve casing portion at only a part of the internal cross section.

[0007]

The injection valve according to the present invention thus constructed has the following advantages. That is, in the injection valve according to the present invention, the notch stress in the intersection region between the internal notch and the inflow hole is significantly reduced, and thus the strength of the injection valve is significantly increased. In the injection valve according to the present invention,
The inflow hole intersects only a part of its internal cross section with the internal notch in the valve casing part of the injection valve. By changing the shape of the transition edge, the material stress acting in the circumferential direction during high pressure loading is advantageously reduced. In this way, the service life and reliability of the injection valve can be increased without great effort or expense in manufacturing.

Further advantageous configurations of the invention are described in claims 2 and below.

In an advantageous configuration of the invention, an inflow hole is provided in the valve casing part from a connection of the valve casing part, the inflow hole extending beyond the internal notch and opposite the connection part of the valve casing part. It extends to the side part. With this configuration, the transition edge from the inflow hole to the internal cutout can be symmetrically shaped, which makes it possible to reduce the cutout stress particularly strongly.

In a particularly advantageous configuration of the invention, the inlet holes are
A section extending beyond the internal notch is connected to the supply hole, which is connected to the injection opening of the injection valve. According to this structure, the high-pressure fuel can be advantageously supplied to the internal cutout of the valve casing portion surrounding the valve member and the supply hole connected to the injection opening through the inflow hole. Therefore, the structure of the injection valve can be simplified. Since no other hole extends from the high pressure connection, the connecting conduit extending from the fuel high pressure accumulator can be screwed directly onto the valve casing part and, for example, the fuel filter can be integrated into the valve casing part. You can

In a particularly advantageous embodiment of the invention, the transition edge between the at least one inlet and the internal cutout of the valve housing part is rounded and chamfered. By forming a rounded edge and varying the shape of the transition edge, improved high pressure strength is obtained in the intersection region. Yet another advantage is that during an electrochemical or other method of introducing a material processing tool into the internal notch of the valve body portion, the transition edge is shaped differently from the prior art, And it is easily accessible.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, embodiments of the present invention will be described with reference to the drawings.

1a and 1b show a fuel injection valve 1 which is known from the prior art, the fuel injection valve 1 being a high-pressure fuel in which high-pressure fuel is continuously supplied by a high-pressure feed pump. It is intended to be used in a fuel injection device equipped with an accumulator. The illustrated fuel injection valve 1 has a valve casing part 4 with an internal cutout 20.
The internal notch 20 has a longitudinal hole 5 formed in a part of its entire length, in which a valve piston 6 is arranged.
One of the ends acts on a valve needle 60 arranged in the nozzle body 65. The valve needle 60 is arranged in the pressure chamber 61, and the fuel under high pressure is supplied to the pressure chamber 61 via the supply hole 8. During the opening stroke movement of the valve piston 6, the valve needle 60 is constantly lifted against the closing force of the spring 63 by the high fuel pressure in the pressure chamber acting on the pressure shoulder 68 of the valve needle. Then, the fuel is injected into the combustion chamber of the internal combustion engine through the injection opening 7 connected to the pressure chamber. The lowering of the valve piston 6 pushes the valve needle in the closing direction into the valve seat 62 of the injection valve, terminating the injection process.

As can be seen in FIG. 1a, the valve piston 6 is guided at its end opposite the valve needle in a cylindrical bore 11, which is provided in the valve member 12, which valve The member 12 is inserted in a coaxial bore 15 which extends the longitudinal bore 5 and has a large diameter.
The valve member 12 is firmly clamped in the flange region 22 via the screw member 23 with the valve casing part 4. The internal notch 20 of the valve casing part 4 further has another term connected to the bore 15 and having a larger diameter, so that the outer peripheral wall of the valve member 12 and the cylindrical inner wall of the further bore. Between them, a ring chamber is formed in the inner cutout 20. The end surface 13 of the valve piston 6 closes the control pressure chamber 14 in the cylindrical hole 11 of the valve member.
Is connected to the high-pressure fuel connection 3 via a supply passage. The supply passage is formed of approximately three parts. A hole 26 extending radially through the wall of the valve member 12
A supply throttle is formed on the inner wall in a part of its entire length and is always connected to a ring chamber which surrounds the valve member 12 over its entire circumference, which ring chamber is provided with a sealing ring 39 in the longitudinal bore. 5 and is always connected via the supply throttle 16 and the fuel filter 42 to the fuel high-pressure connection 3 of the connecting piece 9 which can be screwed into the valve housing part 4. Inflow hole 16
In the injection valve known from the prior art, it opens into the inner notch 20 of the valve casing part 4 over the entire inner cross section. A control pressure chamber 14 is provided via a supply passage having a supply throttle.
Are exposed to high fuel pressure in the fuel high pressure accumulator. Coaxial with the valve piston 6, a hole extending from the control pressure chamber 14 into the valve member 12 is further branched, and this hole forms a fuel discharge passage 17 having a discharge throttle 18. , The fuel discharge passage 17 is provided in the pressure release chamber 1.
9, the pressure release chamber 19 is connected to the fuel low pressure connection portion 1
0, the fuel low pressure connection 10 is further connected to the fuel return line in a manner not shown.
The outflow of the fuel discharge passage 17 from the valve member 12 is performed by the valve member 1
2 is a conical concave portion 21 of the end face located outside
In the area of. A valve seat 24 is formed in the conical portion 21, and a control valve member 25 of a solenoid valve 30 that controls the injection valve cooperates with the valve seat 24. The control valve member 25 is connected to the mover 27.
7 cooperates with the electromagnet of the solenoid valve 30. Since the mover 27 and the control valve member 25 connected to the mover are constantly loaded in the closing direction by the closing spring 31 which is immovably supported with respect to the casing, the control valve member 25 is normally closed. In contact with the valve seat 24 in the position. When the electromagnet is excited, the mover 27 is moved toward the electromagnet, so that the discharge passage 17 is opened toward the pressure release chamber 19.

The opening and closing of the injection valve is controlled by the solenoid valve 30 as described below. Since the mover 27 is always loaded in the closing direction by the closing spring 31, the control valve member 25 is in contact with the valve seat 24 in the closed position and the control pressure chamber 14 is released when the electromagnet is not energized. It is closed to the pressure side 19. As a result, a high pressure is formed there very quickly via the supply channel, which is also present in the fuel high-pressure accumulator. Due to the area of the end face 13, the pressure in the control pressure chamber 14 is
On the contrary, it produces a closing force on the valve needle 60 connected thereto, which closing force is greater than the force acting in the opening direction on the other side by the high pressure present. When the control pressure chamber 14 is opened toward the pressure release side 19 by opening the solenoid valve, the pressure in the slight volume of the control pressure chamber 14 drops very quickly. Because that
This is because the control pressure chamber 14 is blocked from the high pressure side via the supply throttle. As a result, the force exerted on the valve needle in the opening direction is predominant due to the high fuel pressure at the valve needle, so that the valve needle 60 is moved towards the information and at least one injection opening 7 is for injection. Open to the public. However, when the electromagnetic valve 30 closes the fuel discharge passage 17, the pressure in the control pressure chamber 14 can rise again due to the fuel replenished through the supply passage, so that the original closing force is generated and the fuel injection valve is closed. Valve needle closes the injection opening.

2 and 3 each show an injection valve according to the invention in a sectional view. The same reference numerals are used for the same members as in FIGS. 1a and 1b. 2 shows the upper part of the valve casing part 4, the internal notch 20 passing through the casing part 4 being a longitudinal hole 5 and a hole 15, which is coaxially connected to the longitudinal hole 5.
And 35. The holes 15 and 35 are the valve member 12
For receiving the holes in the outer peripheral wall of the valve member 3
A ring chamber is formed with the inner peripheral wall of No. 5. The high-pressure connection 3 is formed on a tube piece 9, which is integrally connected to the valve casing part 4 by, for example, forging. The high-pressure connection 3 has a receiving opening 33 for the fuel filter, from which an inlet opening 16 extends in the valve housing part 4. This inflow hole 16 is shown in FIG.
And as best seen in FIG. 4, the internal notch 20 of the valve casing part 4 is traversed only in part of its internal cross section 44. The inflow hole 16 has an internal cutout 20 in the region of the wall 35 of the cylindrical peripheral wall whose internal cross section 4
Only a portion or portion 45 of 4 is traversed, not a portion 46 of the inner cross section 44. As a result, the shape of the transition edge portion 38 between the inflow hole 16 and the inner wall 35 of the internal cutout 20 changes to a vertically elongated thin contour. "R"
Is the radius of the inflow hole 16, “R” is the radius of the cylindrical peripheral wall-shaped inner wall 35 of the inner cutout 20, and “d” is the center axis 50 of the inflow hole 16 and the center axis 51 of the inner cutout 20. In the case of intervals between, this is obtained if the following two geometric conditions are met at the same time: 1) r + d> R and 2) d-r <R In the embodiment, the central axis 50 of the inflow hole 16 is
The distance d between the inner notch 20 and the central axis 51 of the inner notch 20 is equal to the radius R of the inner notch 20 in the region of the inner wall 35 having a cylindrical peripheral wall shape. The distance d, however, may also be larger or smaller than the radius R of the internal cutout 20. What is important is that the inlet hole only has an internal cutout 44
Is part of that.

As best seen in FIG. 3, the inlet hole 1
6 enters the tubular base body 1 from the receiving portion 33 of the high-voltage connection portion 3 as follows. That is, in this case, the inflow hole 16 is a section 36, which extends beyond the internal notch 20 to some extent in the section of the valve body part 4 opposite the high-pressure connection 3, where the inflow hole 16 or its section 36 is located. , And is connected to the supply hole 8. In the illustrated embodiment, the inlet hole is connected at its end with the supply hole. However, the supply hole 8 may also branch off from the section 36 of the inflow hole 16 in a T-shape. Inflow hole 16 extending from the fuel high pressure connection 3
Supplies the high pressure fuel to the internal recess 20 and the supply hole 8 in an advantageous manner.

In the preferred embodiment shown, the central axis 50 of the inlet hole 16 extends perpendicularly to the central axis 51 of the internal notch 20 of the valve body portion 4, however, also the central axis of the inlet hole 16 is shown. 50 is the central axis 5 of the internal notch 20
It is also possible for the arrangement to extend at an angle different from 90 ° with respect to 1.

In order to increase the strength of the transition edge 38 in the region of intersection of the inner wall 35 and the inflow hole 16, it is advantageous to round and chamfer the transition edge 38. Such machining can be performed, for example, in an electrochemical method, in which a material removal tool is introduced into the internal cutout 20. Due to the good accessibility to the transition edge 38, a relatively large rounding can be formed, which is positive for the strength of the injection valve in the region of intersection of the internal cutout and the inlet hole. Act on.

The present invention is not limited to injection valves for common rail systems, but for all injection valves for internal combustion engines in which the inflow hole for high pressure fuel is connected to the internal cutout of the valve body. Can be used. Due to the fact that the internal notch of the inflow hole is simply notched and the inflow hole is not completely open to the internal notch, it advantageously changes the structure of the transition edge and reduces the notch stress. The high pressure strength of the injection valve can be increased.

[Brief description of drawings]

1a is a cross-sectional view of the upper part of a known injection valve according to the prior art. FIG.

1b is a cross-sectional view showing a lower portion of the injection valve shown in FIG. 1a.

FIG. 2 is a sectional view of a casing portion of the injection valve according to the present invention taken along line II-II of FIG.

FIG. 3 is another sectional view showing a casing portion of the injection valve according to the present invention.

FIG. 4 is a view showing an injection valve according to the present invention in a cross section perpendicular to an inflow hole.

[Explanation of symbols]

1 Fuel Injection Valve, 3 High Pressure Connection, 4 Valve Casing Part, 5 Longitudinal Hole, 6 Valve Piston, 7
Injection opening, 8 supply hole, 9 connecting pipe piece, 10 fuel low pressure connection part, 11 cylindrical hole, 12 valve member, 13
End face, 14 control pressure chamber, 15 hole, 16 supply throttle or inflow hole, 17 fuel discharge passage, 18
Discharge throttle, 19 Pressure release chamber, 20 Internal cutout, 2
1 part, 22 flange area, 23 screw member,
24 valve seats, 25 control valve members, 26 holes, 2
7 mover, 30 solenoid valve, 31 closing spring, 3
5 holes, 36 sections, 38 transition edge, 42 fuel filter, 44 internal cross section, 45, 46 part, 60 valve needle, 61 pressure chamber, 62 valve seat, 63 spring, 65 nozzle body, 68 pressure shoulder

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Stephan Hauk             Federal Republic of Germany Waldenbuchri             -Benecker Veg 24 F-term (reference) 3G066 BA46 CC08T CC68U CC70                       CE22

Claims (6)

[Claims] 1. An injection valve for an internal combustion engine, comprising a valve casing part (4) with an internal cutout (20) having a substantially circular cross section and opening into the internal cutout (20).
In the type provided with an inflow hole (16) for high-pressure fuel, the inflow hole (16) is an internal cutout (20) in the valve casing part and merely a part (45) of the internal cross section (44). An injection valve for an internal combustion engine, which is characterized by intersecting with each other. 2. An inflow hole (16) is provided in the valve casing part from the connection (3) of the valve casing part (4), the inflow hole (16) over the internal notch (20). 2. The injection valve according to claim 1, which extends to a portion of the casing part (4) opposite the connection part (3). 3. The inflow hole (16) has an internal notch (20).
A section (36) extending beyond the valve casing part (4) to the part of the valve casing part (4) opposite the connection part (3) is connected to the supply hole (8), said supply hole (8). The injection valve according to claim 1 or 2, wherein is connected to the injection opening (7) of the injection valve. 4. The transition edge (38) between the at least one inlet hole (16) and the internal cutout (20) of the valve casing part (4) is rounded and chamfered. The injection valve according to any one of items 1 to 7. 5. The inflow hole (16) has an internal cross section (4).
Part of 4), internal cutout (20) in the valve casing part
And a cylindrical inner wall (35) of the inner notch (20).
5. The injection valve according to any one of claims 1 to 4, which intersects in the region of. 6. The method according to claim 1, wherein the central axis (50) of the inflow hole (16) extends perpendicularly to the central axis (51) of the internal cutout (20). Injection valve.