DE102016202949A1 - Electromagnetically controllable suction valve, high pressure pump with such a suction valve and method for controlling the suction valve - Google Patents

Abstract

The invention relates to an electromagnetically controllable suction valve (1) for filling a high-pressure element space (2) of a high-pressure pump (3) with fuel, comprising an annular magnet coil (4) and an armature (5) for actuating a lifting valve piston cooperating with a valve seat (6) (7) which is coupled to the armature (5) or coupled, further comprising a in the opening direction of the suction valve (1) acting spring (8) and a permanent magnet (9) whose magnetic force of the spring force of the spring (8) is opposite. According to the invention, the permanent magnet (9) has an annular shape and is inserted into the armature (5) or into a magnetic core (11) opposite the armature (5) at a working air gap (10). Furthermore, the invention relates to a high pressure pump with such a suction valve (1) and a method for controlling the suction valve (1).

Description

The invention relates to an electromagnetically controllable suction valve for filling a high pressure element space of a high pressure pump with fuel according to the preamble of claim 1. Furthermore, the invention relates to a high-pressure pump for a fuel injection system, in particular a common rail injection system, with such a suction valve and a method for controlling the suction valve.

State of the art

From the DE 10 2013 210 881 A1 is an example of an electromagnetically controllable suction valve for a high pressure pump of a fuel injection system, in particular a common rail injection system, forth, comprising an annular solenoid and a cooperating with the magnetic coil ferromagnetic armature for actuating a valve connected to the armature tappet. The armature is acted upon directly or indirectly by the spring force of a spring. The spring force of the spring keeps the suction valve open when the solenoid is de-energized. If the suction valve is to be closed, the magnetic coil is energized, so that a magnetic field is built up whose magnetic force moves the armature counter to the spring force of the spring. As a result of this movement, the valve tappet connected to the armature is pulled into a valve seat and the suction valve closes.

About the Bestromungszeitpunkt the solenoid thus the closing time of the suction valve is controlled, so that an accurate metering of fuel is possible. The electromagnetically controllable suction valve can replace in this way a separate metering unit. In order to keep the suction valve open even when the pressure in the high-pressure element space of a high-pressure pump increases, in order, for example, to push an excess quantity of fuel from the high-pressure element space back into an inlet region, a correspondingly strong spring is required. Their spring force can in turn be overcome only with a correspondingly high magnetic force to close the suction valve. Further, since in operating points with no or little fuel delivery, the solenoid must be energized to keep the suction valve closed, the energy requirement is relatively high.

To reduce the energy demand, is already in the DE 10 2013 210 881 A1 a permanent acting on the armature permanent whose magnetic force of the spring force of the spring is opposite. Between the permanent magnet and the armature, a ferromagnetic umpolbarer intermediate body is additionally arranged. Depending on the respective polarity of the intermediate body, the magnetic force of the permanent magnet is either strengthened or weakened, so that the armature is held in a first or a second rest position, without that the magnetic coil is energized. This reduces the energy requirement. Furthermore, it requires only a short current pulse to move the armature from a rest position, wherein at the same time the polarity of the intermediate body is given by the energization of the magnetic coil.

Based on the above-mentioned prior art, the present invention seeks to provide an electromagnetically controllable suction valve for a high-pressure pump, the energy requirement is further reduced. Furthermore, the suction valve should be particularly compact, so that the available space is used optimally.

To solve the problem, the electromagnetically controllable suction valve with the features of claim 1 is proposed. Advantageous developments of the invention can be found in the dependent claims. Furthermore, a high-pressure pump with such a suction valve and a method for controlling the suction valve according to the invention are proposed.

Disclosure of the invention

The proposed electromagnetically controllable suction valve, which serves to fill a high-pressure element space of a high-pressure pump with fuel, comprises an annular magnet coil and an armature, by means of which a valve seat can be actuated with a liftable valve piston which can be coupled or coupled to the armature. Further, the suction valve comprises a force acting in the opening direction of the suction valve spring and a permanent magnet whose magnetic force of the spring force of the spring is opposite. According to the invention the permanent magnet is annular and inserted into the armature or in a magnetic core opposite the armature at a working air gap.

The fact that the permanent magnet is inserted into the armature or in a magnetic core opposite the armature at a working air gap, its magnetic force acts directly on the armature. In addition, the arrangement of the permanent magnet within a magnetic circuit, which leads to weakening or amplification of the force acting on the armature magnetic force of the permanent magnet depending on Bestromungsart the solenoid, so that a ferromagnetic umpolbarer intermediate body can be omitted. In this way, at the same time a particularly compact construction arrangement is achieved.

The magnetic force of the permanent magnet counteracts the spring force of the spring. Preferably, there is an equilibrium of forces, so that the armature is held in an idle magnetic coil in a kind of floating state, which defines a third switching position. From this switching position, the suction valve can be opened or closed faster because the path or stroke of the armature is lower. This proves to be an advantage in the start / stop operation of an internal combustion engine, especially when restarting.

If the magnetic coil is energized so that a magnetic field is built up whose magnetic force weakens the magnetic force of the permanent magnet, the spring force of the spring causes the suction valve to open further or to open completely. With appropriate energization of the magnetic coil, however, a magnetic field can be generated whose magnetic force strengthens the magnetic force of the permanent magnet, so that the armature moves against the spring force of the spring in the direction of the magnetic core and closes the suction valve.

According to a first preferred embodiment of the invention, the armature has a pole face facing the magnetic core into which the permanent magnet is inserted. In this way, the arrangement of the permanent magnet requires no additional space. In the pole face of the armature only an annular recess for receiving the permanent magnet is provided.

According to a further preferred embodiment of the invention, the magnetic core has an annular recess for receiving the permanent magnet and / or the magnetic coil. For example, in the magnetic core, an annular coil receiving space may be formed, which has an opening facing the armature, in which the permanent magnet is inserted. Also in this embodiment, the permanent magnet requires no additional space. The anchor is preferably formed in this case as a flat anchor.

In addition, however, the armature can also be designed as a plunger anchor, which is opposite to the working air gap serving as an inner pole portion of the magnetic core. The permanent magnet can be integrated in both the pole face of the armature, as well as in the pole face of the inner pole.

Preferably, the spring is received in a central recess of the magnetic core. The space is used optimally in this way. Furthermore, a guide of the spring can be effected via the magnetic core.

Alternatively or additionally, it is proposed that the spring surround the valve piston. About the valve piston also a guide of the spring can be effected.

In a further development of the invention, it is proposed that the valve piston is penetrated by an axial bore, which is delimited on the one hand by a pressure surface facing the high pressure element space and on the other hand by a sealing contour cooperating with the valve seat. The sealing contour is therefore formed on the end face of the valve piston facing away from the high pressure element space, so that the same pressure is applied in the axial bore of the valve piston as in the high pressure element space. In this way, a valve piston can be realized, which is substantially pressure balanced. A pressure compensated valve piston allows a reduction of the switching forces, so that the energy requirement can be further reduced.

In order to realize a largely pressure balanced valve piston, the pressure surface facing the high pressure element space is preferably made comparatively small. For example, a plate-shaped portion for forming a sealing contour can be omitted, since it is now arranged on the side facing away from the printing surface. To a reduction of the pressure surface also contributes to the valve piston passing through axial bore. If, in the open position of the valve, the pressure in the high-pressure element space increases, a reduced hydraulic closing force acts on the valve piston due to the reduced pressure surface. Accordingly, a smaller spring can be selected, which keeps the suction valve open when the solenoid is de-energized. As a result, space can be saved again.

In contrast to the valve closing element of the known suction valve described above, the valve piston of the suction valve according to the invention in the open position is not flowed around by inflowing fuel, but flows through, wherein the feed takes place in the Hochdruckelementraum on the valve piston passing through axial bore.

Preferably, the valve piston is passed through a central recess of a valve body surrounding the magnetic core. This ensures that the valve piston comes into contact with a valve seat lying outside the magnetic circuit.

Further preferably, at least one intake passage is formed in the valve body in order to secure the supply of fuel in the direction of the valve seat. Preferably, the intake passage is designed in a side facing away from the armature end face of the valve body as a radially extending groove. A groove can be produced easily and inexpensively. Preferably, a plurality of such grooves in the same angular distance arranged to each other, so that the valve seat is flowed evenly over its circumference.

The designed as a groove intake passage is further preferably limited by a body member, which also forms the valve seat. This may be a plate-shaped body member, which is attached to the valve body. The valve seat can be designed as a simple flat seat, against which seals the sealing contour of the valve piston. To optimize the sealing force, the sealing contour is preferably formed by a frontal biting edge of the valve piston.

Furthermore, a high-pressure pump for a fuel injection system, in particular a common-rail injection system, with a suction valve according to the invention is proposed. Preferably, the suction valve is integrated in a cylinder head of the high-pressure pump. In this way, the space requirement can be further minimized.

It is also proposed that a pressure surface exhibiting the end portion of the valve piston is guided in a stroke of the cylinder head forming the high pressure element space bore. The number of components can be further reduced by this measure, so that the suction valve is simple and inexpensive to produce.

In addition, a method for controlling the suction valve according to the invention is proposed. In the method, a magnetic field is generated by the magnetic coil whose magnetic force strengthens or weakens the magnetic force of the permanent magnet. Whether a gain or weakening of the magnetic force of the permanent magnet is achieved depends on the type of current applied. Depending on the Bestromungsart the solenoid therefore the suction valve can be closed or opened.

Preferably, the armature is held in de-energized magnetic coil on the spring force of the spring and the magnetic force of the permanent magnet in a floating state. In this way, a third switching position or an intermediate switching position is defined, which increases the dynamics of the armature. For the complete opening or closing of the suction valve can be effected with a smaller stroke of the anchor.

Preferred embodiments of the invention are explained below with reference to the accompanying drawings. These show:

1 a schematic longitudinal section through an electromagnetically actuated suction valve according to a first preferred embodiment of the invention,

2 a schematic cross section through the suction valve of 1 .

3 a schematic longitudinal section through an electromagnetically actuated suction valve according to a second preferred embodiment of the invention.

Detailed description of the drawings

That in the 1 illustrated electromagnetically controllable suction valve 1 serves to fill a high-pressure element space 2 a high pressure pump 3 with fuel. The suction valve 1 is this in a cylinder head 23 the high pressure pump 3 integrated, in which also the high-pressure element space 2 is trained.

The suction valve 1 includes one with a valve seat 6 cooperating liftable valve piston 7 that with an anchor 5 coupled in the 1 is designed as a flat anchor. The anchor 5 is located at a working air gap 10 a magnetic core 11 with an annular recess 13 opposite, in which a magnetic coil 4 is included. In the recess 13 is also a permanent magnet 9 used so that this together with the magnetic core 11 and the anchor 5 the working air gap 10 limited. The magnetic force of the permanent magnet 9 thus acts directly on the anchor 5 one. At the same time, it forms a counterforce to the spring force of a spring 8th out, in a central recess 14 of the magnetic core 11 is included and on the one hand at anchor 5 on the other hand on a valve body 19 is supported, the magnetic core 11 surrounds.

With de-energized magnetic coil 4 keep the magnetic force of the permanent magnet 9 and the spring force of the spring 8th the anchor 5 in an intermediate switching position, in which the suction valve 1 Although open, but not fully open. To the suction valve 1 close, the solenoid is 4 energized, so that a magnetic field is built up whose magnetic force, the magnetic force of the permanent magnet 9 strengthened and the anchor 5 against the spring force of the spring 8th in the direction of the magnetic core 11 is pulled to the working air gap 10 close. Because the valve seat 6 is on the the high-pressure element space 2 opposite side of the valve piston 7 arranged and is by a body component 22 formed, attached to the valve body 19 is scheduled. The inlet of fuel in the direction of the valve seat 6 via intake ducts 20 that in a body part 22 facing end face 21 of the valve body 19 are formed as radially extending grooves (see 2 ).

To be in contact with the valve seat 6 to get to, is the valve piston 7 through a central recess 18 of the valve body 19 guided. At his the valve seat 6 facing end is the valve piston 7 with a sealing contour 17 Mistake. The sealing contour 17 limited one the valve piston 7 penetrating axial bore 15 directly into the high-pressure element space 2 the high pressure pump 3 empties. The axial bore 15 is here from a printing surface 16 limited to one end portion 24 is formed, over which the valve piston 7 in a hole 25 of the cylinder head 23 the high pressure pump 3 Hubbeweglich is guided. The guide is designed narrow, so that the high-pressure element space 2 is sealed to the outside.

To the suction valve 1 to open or completely open, the solenoid is 4 energized in such a way that a magnetic field is built up whose magnetic force, the magnetic force of the permanent magnet 9 which counteracts the spring force of the spring 8th forms, weakens. The feather 8th then can the suction valve 1 to open or completely open.

A modification of the suction valve 1 of the 1 is in the 3 shown. Here is the anchor 6 designed as a solenoid and the permanent magnet 9 is in a magnetic core 11 facing pole surface 12 of the anchor 5 integrated. The permanent magnet 9 is a serving as an inner pole portion of the magnetic core 11 across from. The magnetic core 11 has for this purpose a slightly modified cross-sectional shape, which takes into account the Tauchankerprinzip. Incidentally, the suction valve 1 of the 3 equal to the 1 trained, so that reference is made to the preceding embodiments.

The invention is not limited to the illustrated preferred embodiments, but also includes other modifications. In particular, individual features of the illustrated embodiments are interchangeable or combinable with each other.

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102013210881 A1 [0002, 0004]

Claims (12)

Electromagnetically controllable suction valve ( 1 ) for filling a high pressure element space ( 2 ) a high pressure pump ( 3 ) with fuel, comprising an annular magnet coil ( 4 ) and an anchor ( 5 ) for actuating one with a valve seat ( 6 ) cooperating liftable valve piston ( 7 ), with the anchor ( 5 ) is coupled or coupled, further comprising in the opening direction of the suction valve ( 1 ) acting spring ( 8th ) and a permanent magnet ( 9 ) whose magnetic force of the spring force of the spring ( 8th ), characterized in that the permanent magnet ( 9 ) annular and in the anchor ( 5 ) or in an anchor ( 5 ) at a working air gap ( 10 ) opposite magnetic core ( 11 ) is used. Suction valve ( 1 ) according to claim 1, characterized in that the armature ( 5 ) a the magnetic core ( 11 ) facing pole surface ( 12 ), in which the permanent magnet ( 9 ) is used. Suction valve ( 1 ) according to claim 1 or 2, characterized in that the magnetic core ( 11 ) an annular recess ( 13 ) for receiving the permanent magnet ( 9 ) and / or the magnetic coil ( 4 ) having. Suction valve ( 1 ) according to one of the preceding claims, characterized in that the spring ( 8th ) in a central recess ( 14 ) of the magnetic core ( 11 ) is received and / or the valve piston ( 7 ) surrounds. Suction valve ( 1 ) according to one of the preceding claims, characterized in that the valve piston ( 7 ) from an axial bore ( 15 ) is interspersed, on the one hand by a high-pressure element space ( 2 ) facing pressure surface ( 16 ) and on the other hand from one with the valve seat ( 6 ) cooperating sealing contour ( 17 ) is limited. Suction valve ( 1 ) according to one of the preceding claims, characterized in that the valve piston ( 7 ) by a central recess ( 18 ) of a valve body ( 19 ) is passed, the magnetic core ( 11 ) surrounds. Suction valve ( 1 ) according to claim 6, characterized in that in the valve body ( 19 ) at least one intake duct ( 20 ) is formed, preferably in an anchor ( 5 ) facing away from the end face ( 21 ) of the valve body ( 19 ) is designed as a radially extending groove. Suction valve ( 1 ) according to claim 7, characterized in that the groove designed as a suction channel ( 20 ) of a body component ( 22 ), which further defines the valve seat ( 6 ), which is preferably designed as a flat seat. High-pressure pump for a fuel injection system, in particular a common-rail injection system, with a suction valve ( 1 ) according to one of the preceding claims, wherein preferably the suction valve ( 1 ) in a cylinder head ( 23 ) of the high-pressure pump ( 3 ) is integrated. High pressure pump according to claim 9, characterized in that a pressure surface ( 16 ) end section ( 24 ) of the valve piston ( 7 ) in a high-pressure element space ( 2 ) forming bore ( 25 ) of the cylinder head ( 23 ) is guided in a liftable manner. Method for controlling a suction valve ( 1 ) according to one of claims 1 to 8, characterized in that by means of the magnetic coil ( 4 ) is generated, a magnetic field whose magnetic force, the magnetic force of the permanent magnet ( 9 ) strengthens or weakens. A method according to claim 11, characterized in that when energized magnetic coil ( 4 ) the anchor ( 5 ) about the spring force of the spring ( 8th ) and the magnetic force of the permanent magnet ( 9 ) is kept in a suspended state.

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