JPH0223711B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention comprises a valve needle which opens under the influence of fuel pressure against the force of a closing spring, and at least one valve needle connected to an evaluation circuit and fixed immovably relative to the valve carrier. A fuel injection valve for an internal combustion engine having two induction coils, in which at least one magnetic flux acts in the core region of the induction coil, the magnetic flux forming a permanent magnet surrounded by the induction coil. It is of the type that is produced by the valve needle and is varied in relation to the position of the valve needle by a part that moves together with the valve needle.

The start of injection of a fuel injector is only accurately measured at the fuel injector itself. For this reason, significant efforts have been made to develop signal generators located directly on the fuel injectors. Due to the narrow design of the valve and the short stroke of the moving parts in the valve, it is considerably more difficult to measure the injection onset at the fuel injection itself than, for example, in a fuel injection pump. In the case of known fuel injection valves of the type mentioned at the outset, the induction coil is arranged in a chamber separated from the inner chamber filled with fuel, and the valve needle is arranged in an extension provided with a permanent magnet. , the extension of which is guided from the inner chamber through the bushing into the core area of the induction coil. A disadvantage of this known fuel injection valve is that its external dimensions are significantly larger than those of mass-produced fuel injection valves without induction coils.

Therefore, it is an object of the present invention to improve the fuel injection valve of the type mentioned at the beginning, and to substantially reduce the external dimensions of a mass-produced fuel injection valve without an induction coil, even though it has an induction coil. The object of the present invention is to provide a fuel injection valve as compact as the present invention.

In order to solve this problem, in the configuration of the present invention,
An induction coil is disposed in an insert of magnetically impermeable material inserted into the valve retainer and at least partially surrounded by the valve retainer, and at least one permanent magnet is disposed within the insert. The permanent magnet is housed in a fixed position and is coupled to the magnetically permeable part of the valve holder via a magnetically permeable bridge member, such that the magnetic flux of the permanent magnet passing through the induction coil connects the bridge member and the valve holder. a retaining body; a retaining ring extending with a slight radial play within the valve retaining body and connected to the valve needle; and a permanent magnet or a permanent magnet coupled to the retaining ring that changes with the stroke of the valve needle; It is closed via the axial gap between the soft iron part and the soft iron part.

Configured according to the invention, the external dimensions of a mass-produced fuel injector without an induction coil, while retaining the advantage that the start of fuel injection can be precisely measured in the fuel injector itself using an induction coil. This results in a fuel injection valve that does not substantially exceed .

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a fuel injection valve in longitudinal section. A valve needle 3, which opens outwardly, is assigned to the valve body 2 of this fuel injection valve. Valve body 2
A pressure spring, which is a closing spring 7, which keeps the valve needle 3 in the closed position, is compressed between the flange-shaped part 4 of the valve and the spring receiver in the form of a stopper sleeve 5. In addition, stoppa sleeve 5
is connected via a retaining ring 8 to a valve needle end 9 which is designed in the form of a head. This valve needle end 9 is guided through the retaining ring 8 by means of an inlet hole, which is not shown in the drawings, and is brought into the locking position after being guided through it. Retaining ring 8
projects beyond the valve needle end 9 and forms a ring 11 there. End face 1 of this ring 11
2 is located perpendicular to the axis of the valve needle 3;
A gap of equal width with the end face 15 of the insert 17 which is located opposite the end face 12 and serves as a connecting tube piece.
14 is formed. The insert 17 is screwed into the sleeve-shaped valve holder 18 and, at the outer edge of the end face 15 , makes intimate contact with a shoulder 20 provided on the inside of the valve holder 18 via a spacer ring 19 . are doing. As a result, the flange-like portion 4
The inner chamber 22 filled with fuel is sealed between the end face 15 and the inner chamber 22 . In this case, the valve body 2 is pressed tightly against the end face of the valve holder 18 via the portion 4 by means of a cap nut 23.

In order to maintain the position of the retaining ring 8 or the end face 12 at right angles to the axis of the valve needle 3, the stop sleeve 5 has a guide section 25 which surrounds the fitting section 26 of the valve needle 3.

In its normal configuration, the insert 17 has a connecting thread 27 for connecting a high-pressure conduit and a fuel supply hole 28.
It has This fuel supply hole 28 is connected to the insert 1
It opens into the inner chamber 22 at the end surface 15 of 7 .
Furthermore, two blind holes 29 are provided in the insert body 17 and extend in the axial direction from the end surface 15, and rod-shaped permanent magnets 30 are inserted into each of the blind holes.
The entire insert 17 consists of a magnetically impermeable, unmagnetized material. The rod-shaped permanent magnet 30 is however held in the blind hole 29 by a first soft iron part 31 which acts as a closure. This first soft iron section 31 is magnetically coupled to the interior chamber 22 . At the ends of the permanent magnets 30 facing away from the inner chamber 22, a second soft iron part 32 is attached in each case, the second soft iron parts 32 of both permanent magnets 30 being arranged in the transverse bore. They are magnetically coupled by soft iron pins 33. Second soft iron part 3
2 provides a better magnetic coupling between the permanent magnet 30 and the soft iron pin 33, so that the second soft iron part 32 and the soft iron pin 33 together act as a bridge member. A soft iron pin 33 is located in the area of the internal thread 35 for screwing the insert 17 into the valve holder 18 . This results in a magnetic coupling between the soft iron pin 33 and the valve holder 18, which is also made of magnetically permeable material, in this connecting position. In this case, the soft iron pin 33 also serves to secure the insert 17 to the valve holder 18.

In the area between the internal thread 35 and the spacer ring 19 made of magnetically impermeable material there is an insert 1
An induction coil 37 is arranged in a recess 36 provided on the outer circumferential surface of 7, the connecting conductor 38 of which is passed outwardly through a groove 39 provided in the insert 17 in the area of the internal thread 35. You will be guided to.

The cross section shown in FIG. 2 shows the position of the second soft iron part 32 and the rod-shaped permanent magnet 30 with respect to the axis of the fuel injection valve and the fuel supply hole 28. In this case, the permanent magnet 30 is located in an extension of the end face 12 of the retaining ring 8.

By configuring the fuel injection valve as described above, a magnetic circuit is generated, and the magnetic flux of this magnetic circuit is passed through the soft iron pin 33 to the valve holder 18, and is passed through the valve holder 18 to the induction coil. 37 on the outside, it again reaches the permanent magnet 30 via the valve body 2, the valve needle 3, the retaining ring 8, the gap 14 and the first soft iron part 31 following this gap. Furthermore, in this case the magnetic flux can also be transferred to the retaining ring 8 by means of a shorter coupling, ie via the gap 40 formed between the retaining ring 8 and the valve retainer 18 which radially surrounds this retaining ring 8. It is extremely important that this is achieved.

When fuel is supplied under pressure to the inner chamber 22 starting from the closed position of the valve needle 3, the valve needle 3 slides in the axial direction and the fuel is ejected at the valve body 2.
The gap 14 increases, increasing the resistance in the magnetic circuit and causing magnetic flux changes. This magnetic flux change causes a corresponding induced voltage in the induction coil 37, which is connected to the evaluation device via the connecting conductor 38. The retaining ring 8 provided in this embodiment makes it possible to realize a relatively large area penetrated by the magnetic flux.

With the above-described embodiment of the fuel injection valve, the external dimensions of a mass-produced fuel injection valve without a needle stroke signal generator or an injection start signal generator can be maintained in a simple manner. The arrangement according to this embodiment can form a defined and continuous magnetic circuit. During the variable width 14, which indicates the position of the valve needle 3, the magnetic flux is radially cut off from the retaining ring 8 by the spacer ring 19, which at the same time acts as a sealing ring, so that the magnetic flux is approximately It can only be changed by a movement of the valve needle 3 or a movement of the retaining ring 8.

The second embodiment shown in FIG. 3 has substantially the same structure as the first embodiment shown in FIG. The difference is that the insert 1 in the embodiment shown in FIG.
7 and the valve holder 18 are combined into one member as a valve holder 18'. As a result, the female thread 35 in the first embodiment is eliminated. The entire valve holder 18' is made of a magnetically permeable material, such as soft iron, and is of sleeve-like design as in the first embodiment. In this case, the valve holder 1
One end of 8' is connected to the flange-like part 4 of the valve body 2.
The valve body 2 is held at its flange-like portion 4 by a cap nut 23 screwed to the valve holding body 18'. As a result, an inner chamber 22 is formed inside the valve retainer 18', as in the first embodiment, into which the valve needle 3 projects together with the retainer ring 8. The valve holder 18' has a vertical hole 42 on its connecting side, into which a substantially rod-shaped insert 43 made of a magnetically impermeable material is inserted. It is. In a manner similar to the insert 17, the insert 43 closes off the inner chamber 22 on one end side at the end opposite the valve body 2. In this case, the end face 15' is perpendicular to the axis of the valve needle 2 and the retaining ring 8, forming a gap 14.
It is located parallel to the end surface 12 of. At the connection end and the interior end of the insert 43, the insert 43 is in each case tightly connected to the valve carrier 18'. In this case, the tight connection can be effected, for example, by electron beam welding. An induction coil 37 is disposed on the outer periphery of the insert 43 between both welding locations in the insert 43, as in the first embodiment. In this case, the connecting wire 38 of the induction coil 37 is guided outwards via a recess 45 provided in the valve carrier 18'. A fuel supply hole 28 extends inside the insert 43 . Further, a bar-shaped permanent magnet 30 is inserted into a hole parallel to the axis provided in the insert body 43, so that the permanent magnet 30
A magnetic connection is created which leads from the first soft iron part 31, which serves as a closure pair, to the interior chamber 22 and via the gap 14 to the retaining ring 8. The permanent magnet 30 has a second soft iron section 32 and a third section acting as bridge members as in the first embodiment.
It is magnetically coupled to the valve holder 18' via a soft iron pin (not shown). This second
The fuel injection valve according to the embodiment has almost the same characteristics as the fuel injection valve according to the first embodiment described above. The advantage of this second embodiment is that the female thread 35 and the spacer ring 19 fit into the inner space 2 at this location.
The second seal is omitted. The fuel injection valve according to the invention is generally easy to manufacture and assemble. Sealing problems have also been solved, for example by electron beam welding.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view showing a first embodiment of a fuel injection valve according to the present invention, FIG. 2 is a cross-sectional view of the fuel injection valve shown in FIG. 1, and FIG. 3 is a second embodiment. FIG. 2... Valve body, 3... Valve needle, 4... Flange-shaped portion, 5... Stopper sleeve, 7... Closing spring, 8... Retaining ring, 9... Valve needle end, 11... Ring, 12, 15, 15'... End face, 14... Interval, 17, 43... Insert, 1
8, 18'... Valve holding body, 19... Spacer ring, 20... Shoulder, 22... Inner chamber, 23... Cap nut, 25... Guide portion, 26... Compatible portion, 27...
... Connection thread, 28 ... Fuel supply hole, 29 ... Blind hole, 30 ... Permanent magnet, 31 ... First soft iron part, 32 ... Second soft iron part (bridge member),
33... Soft iron pin (bridge member), 35... Female thread, 36... Notch, 37... Induction coil,
38...Connection conductor, 39...Groove, 40...Between,
42... Vertical hole, 45... Notch.

Claims (1)

Claims: 1. A valve needle 3 which opens under the action of fuel pressure against the force of a closing spring 7 and which is connected to an evaluation circuit and fixed immovably to the valve holder 18, 18'. A fuel injection valve for an internal combustion engine having at least one induction coil 37 , in which at least one magnetic flux acts in the core region of the induction coil 37 .
In the type in which the induction coil 37 is produced by a permanent magnet 30 surrounded by the valve holder 18 and is varied in relation to the position of the valve needle 3 by a part moving together with the valve needle 3. .
is housed in a fixed position, and the permanent magnet is connected to the valve holder 1 via magnetically permeable bridge members 32 and 33.
8, 18', and the magnetic flux passing through the induction coil 37 of the permanent magnet 30 is
Bridge members 32, 33 and valve retainers 18, 18'
a retaining ring 8 extending with a slight radial play in the valve holder and connected to the valve needle 3; a retaining ring 8 and a permanent magnet 30 or the permanent magnet varying with the stroke of the valve needle 3; The axial distance between the soft iron part 31 connected to the
A fuel injection valve for an internal combustion engine, characterized in that it is closed through. 2 At least one permanent magnet 30 is inserted into the insert part 1 of the magnetically impermeable material of the valve holder 18, 18'.
7, 43, this insertion portion 17, 4
3, which is held by a first soft iron part 31 inserted tightly into the fuel injector, which soft iron part 31 is adjacent to the fuel injection valve interior 22, which is filled with fuel. The fuel injection valve according to item 1. 3 The end face 15 of the first soft iron part 31, which is the limiting face for the inner chamber 22, is located at right angles to the travel direction of the valve needle 3, so that the valve needle 3 has one end face 12 of the first soft iron part A retaining ring 8 forming, together with the end face 15 of the part 31, an equally wide gap 14
2. A fuel injection valve according to claim 2, which is combined with a fuel injection valve. 4 A second soft iron portion 32 is provided at the end of the permanent magnet 30 located opposite to the first soft iron portion 31, which second soft iron portion 32 connects the insertion portion or the valve holder. The fuel injection valve according to claim 3, wherein the fuel injection valve is magnetically coupled to the valve holder 18, 18' via a soft iron pin 33 inserted into a horizontal hole passing through the insertion portion. . 5. The fuel injection valve according to claim 4, wherein the permanent magnet is configured as a bar magnet. 6. The fuel injection according to claim 5, wherein two bar magnets are inserted into the insertion portions 17, 43 in parallel with their axes, and both bar magnets are magnetically coupled to each other via a soft iron pin 33. valve. 7. The fuel injection valve according to claim 1, wherein the induction coil 37 is disposed on the outer peripheral surface of the insertion portion 17, 43 and surrounded by the valve retainer 18, 18'. 8 The insertion part on the fuel connection side of the valve retainer 18' is
8. The fuel injection valve according to claim 7, wherein the fuel injection valve is constructed as an axially extending insert 43 having a fuel supply hole 28 communicating with the interior chamber 22. 9 The insertion part 17 is designed as a connecting piece for the valve holder 18, which connecting piece seals off the inner chamber 22 of the fuel injection valve on its end side and has a fuel supply hole 28. The fuel injection valve according to range 7.