DE102017217489A1 - Electromagnetically actuated inlet valve and high-pressure pump with inlet valve - Google Patents

Abstract

An electromagnetically actuatable inlet valve (24) for a high-pressure pump, in particular a fuel injection system, is proposed. The inlet valve (24) has a valve member (34) which is movable between an open position and a closed position. An electromagnetic actuator (60) is provided, through which the valve member (34) is movable, wherein the electromagnetic actuator (60) comprises a magnetic coil (64), a magnetic core (66) and an armature acting at least indirectly on the valve member (34) (68) which is displaceably guided in a receptacle (76) of a carrier element (78) in the direction of its longitudinal axis (69). The magnetic core (66) and the carrier element (78) are surrounded by a housing (70). In the housing (70) is in an intermediate space (94) between the housing (70) on the one hand and the carrier element (78) and / or the magnetic core (66) and / or a magnetic core (66) and the carrier element (78) interconnecting On the other hand, at least one sacrificial anode (96) is arranged connecting element (92). The at least one sacrificial anode (96) is electrically conductively connected to the carrier element (78) and / or the magnetic core (66) and / or the connecting element (92). The at least one sacrificial anode (96) consists of a less noble metal than the carrier element (78) and / or the magnetic core (66) and / or the connecting element (92).

Description

The invention relates to an electromagnetically operable inlet valve for a high pressure pump, in particular a fuel injection system, according to the preamble of claim 1. Furthermore, the invention relates to a high pressure pump with such an inlet valve.

State of the art

An electromagnetically actuated intake valve for a high-pressure pump of a fuel injection system, is characterized by the DE 10 2015 212 390 A1 known. The high-pressure pump has at least one pump element with a pump piston driven in a stroke movement, which delimits a pump working space. The pump working space can be connected to an inlet for the fuel via the inlet valve. The inlet valve comprises a valve member which cooperates with a valve seat for control and which is movable between an open position and a closed position. In its closed position, the valve member comes to rest against the valve seat. Furthermore, the inlet valve comprises an electromagnetic actuator, through which the valve member is movable. The electromagnetic actuator has a magnetic coil, a magnetic core and an at least indirectly acting on the valve member armature. The magnet armature is displaceably guided in a receptacle in a carrier element. When the solenoid is energized, the armature is movable against the force of a return spring. The carrier element and the magnetic core are connected to each other via a sleeve-shaped connecting element, wherein the connecting element can be welded to the carrier element and / or the magnetic core. The magnetic core, the carrier element and the connecting element are surrounded by a housing.

Between the magnetic core, the support element and the connecting element on the one hand and the housing on the other hand, a gap is present, which is filled with air. Upon heating and cooling of the actuator, moisture may enter the gap from the environment of the actuator. This can lead to corrosion of the carrier element, magnet armature and connecting element, wherein in particular the welded joint of the connecting element can be damaged, so that no secure connection of the magnetic core with the carrier element is more present. Even if sealing measures are provided on the housing, a reliable hermetic seal can not be ensured, so that corrosion can not be ruled out.

Disclosure of the invention

Advantages of the invention

The inlet valve according to the invention with the features of claim 1 has the advantage that the magnetic core and / or the carrier element and / or the connecting element are protected by the at least one sacrificial anode from corrosion. If moisture is present, there is corrosion of the sacrificial anode and not the components connected to it.

In the dependent claims advantageous refinements and developments of the inlet valve according to the invention are given. In the claims 3 to 6 particularly advantageous embodiments and arrangements of at least one sacrificial anode are given. In claim 7, an advantageous choice of material for the at least one sacrificial anode is specified.

drawing

Several embodiments of the invention are described below with reference to the accompanying drawings. Show it 1 a schematic longitudinal section through a high-pressure pump, 2 in an enlarged view a in 1 with II designated section with the inlet valve of the high pressure pump with a sacrificial anode according to a first embodiment, 3 the intake valve with the sacrificial anode according to a second embodiment, 4 the intake valve with the sacrificial anode according to a third embodiment, 5 the intake valve with the sacrificial anode according to a fourth embodiment and 6 the intake valve with the sacrificial anode according to a fifth embodiment.

Description of the embodiments

In 1 is fragmentary illustrated a high-pressure pump, which is provided for fuel delivery in a fuel injection system of an internal combustion engine. The high-pressure pump has at least one pump element 10 on, which in turn is a pump piston 12 has, which is driven by a drive in a lifting movement, in a cylinder bore 14 a housing part 16 the high-pressure pump is guided and in the cylinder bore 14 a pump workroom 18 limited. As a drive for the pump piston 12 can be a drive shaft 20 with a cam 22 or eccentric be provided on which the pump piston 12 directly or via a plunger, for example a roller tappet, supported. The pump workroom 18 is via an inlet valve 24 with a fuel feed 26 connectable and via an outlet valve 28 with a memory 30 , During the suction stroke of the pump piston 12 can the pump work space 18 with the inlet valve open 24 be filled with fuel. During the delivery stroke of the pump piston 12 is through this with closed inlet valve 24 Fuel from the pump workspace 18 displaced and in the memory 30 promoted.

In the housing part 16 The high pressure pump closes as in 2 shown on the cylinder bore 14 on the pump piston 12 opposite side a through hole 32 with a smaller diameter than the cylinder bore 14 on the outside of the housing part 16 empties. The inlet valve 24 has a piston-shaped valve member 34 on, the one in the through hole 32 slidably guided shaft 36 and one in diameter over the shaft 36 bigger head 38 that is in the pump workspace 18 is arranged. At the transition from the cylinder bore 14 for through-hole 32 is on the housing part 16 a valve seat 40 formed, with which the valve member 34 with one on his head 38 trained sealing surface 42 interacts.

In one to the valve seat 40 subsequent section has the through hole 32 a larger diameter than in the shaft 36 of the valve member 34 leading section, leaving a the shaft 36 of the valve member 34 surrounding annulus 44 is formed. In the annulus 44 open one or more inlet holes 46 on the other hand, on the outside of the housing part 16 lead.

The shaft 36 of the valve member 34 stands out on the pump work space 18 opposite side of the housing part 16 from the through hole 32 out and on this is a support element 48 attached. On the support element 48 supports a valve spring 50 on the other hand, on one the shaft 36 of the valve member 34 surrounding area of the housing part 16 supported. Through the valve spring 50 becomes the valve member 34 acted upon in a direction of adjustment A in the closing direction, wherein the valve member 34 in its closed position with its sealing surface 42 at the valve seat 40 is applied. The valve spring 50 is designed for example as a helical compression spring.

The inlet valve 24 is by an electromagnetic actuator 60 operable, in particular in the 2 and 3 is shown. The actor 60 is by an electronic control device 62 triggered depending on operating parameters of the engine to be supplied. The electromagnetic actuator 60 has a magnetic coil 64 , a magnetic core 66 and a magnet armature 68 on. The electromagnetic actuator 60 is on the pump work space 18 opposite side of the inlet valve 24 arranged. The magnetic core 66 and the magnetic coil 64 are from an actuator housing 70 surrounded, on the housing part 16 the high pressure pump can be fastened. The actuator housing 70 is made of plastic and in this is the magnetic coil 64 added. The actuator housing 70 is for example by means of this cross-over screw ring 72 on the housing part 16 fastened on an externally threaded collar 74 of the housing part 16 is screwed on.

The magnet armature 68 is at least substantially cylindrical and formed over its outer shell in a receptacle in the form of a bore 76 in a carrier element 78 in the direction of its longitudinal axis 69 slidably guided. The hole 76 in the carrier element 78 is at least approximately coaxial with the through hole 32 in the housing part 16 the high-pressure pump and thus to the valve member 34 , To the hole 76 closes in the carrier element 78 to the inlet valve 24 out another hole 77 with a smaller diameter than the hole 76 at.

The magnet armature 68 has an at least approximately coaxial to the longitudinal axis 69 of the magnet armature 68 arranged central blind hole 81 on, in the one on the valve member 34 opposite side of the armature 68 arranged return spring 82 protrudes, located on the armature 68 supported. The return spring 82 is at its other end at least indirectly on the magnetic core 66 supported, which has a central blind hole 84 in which the return spring 82 protrudes. In the hole 84 of the magnet armature 66 can be a support element 85 for the return spring 82 inserted, for example, be pressed. The magnet armature 68 has one or more passage openings 91 on to a passage of fuel during the movement of the armature 68 to enable.

In the hole 76 is through the diameter reduction to further drilling 77 an annular shoulder 88 educated. Between the ring shoulder 88 and the armature 68 can be a stop element 90 be arranged by the movement of the armature 68 to the inlet valve 24 is limited. The stop element 90 is sleeve-shaped and through this protrudes the armature 68 to the inlet valve 24 through and comes at least indirectly on the valve member 34 to the plant. The magnetic core 66 and the carrier element 78 are about a sleeve-shaped connecting element 92 connected to each other on the magnetic core 66 and on the carrier element 78 by means of a welded joint 93 is attached.

Between the carrier element 78 , the magnetic core 66 and the connecting element 92 on the one hand and the surrounding actuator housing 70 On the other hand, there is a gap 94 available. Of the gap 94 extends in the radial direction with respect to the longitudinal axis 69 of the magnet armature 68 between the carrier element 78 , the connecting element 92 and the magnetic core 66 on the one hand and the actuator housing 70 on the other hand. In the direction of the longitudinal axis 69 of the magnet armature 68 the gap extends 94 along the carrier element 78 , of the connecting element 92 and the magnetic core 66 to the carrier element 78 remote end of the magnetic core 66 ,

According to the invention is in the space 94 at least one sacrificial anode 96 arranged with the support element 78 and / or the connecting element 92 and / or the magnetic core 66 is electrically conductively connected and which consists of a less noble metal as the carrier element 78 and / or the connecting element 92 and / or the magnetic core 66 , The carrier element 78 , the connecting element 92 and the magnetic core 66 are usually made of ferrous alloys or steel. The at least one sacrificial anode 96 For example, it is made of magnesium or aluminum or an alloy containing at least one of these metals.

In 2 is the inlet valve 24 with the sacrificial anode 96 shown according to a first embodiment. Here is the sacrificial anode 96 sleeve-shaped and surrounds the connecting element 92 at least over part of its scope, preferably over its entire circumference. In the direction of the longitudinal axis 69 of the magnet armature 68 The sacrificial anode extends over almost the entire length of the connecting element 92 , The sacrificial anode 96 is in the actuator housing 70 inserted, in particular pressed over its outer sheath in this. The sacrificial anode 96 is preferably with the carrier element 78 or alternatively with the connecting element 92 or the magnetic core 66 connected electrically conductive. The electrically conductive connection of the sacrificial anode 96 with the carrier element 78 , the connecting element 92 or the magnetic core 66 may be by direct contact or, for example, via at least one of the sacrificial anode 96 radially inwardly protruding preferably resilient contact arm 97 respectively. When mounting the actuator housing 70 on the carrier element 78 and the magnetic core 66 becomes the electrically conductive compound of the sacrificial anode 96 produced. Because the magnetic core 66 with the carrier element 78 over the connecting element 92 is connected and these parts are made of electrically conductive material results from the sacrificial anode 96 a corrosion protection for these parts regardless of which of the parts the sacrificial anode 96 electrically conductive is connected.

In 3 is the inlet valve 24 with the sacrificial anode 96 according to a second embodiment, wherein the sacrificial anode 96 in the area of the magnetic core 66 is arranged. The sacrificial anode 96 is annular and surrounds the magnetic core 66 at least over part of its scope, preferably over its entire circumference. The sacrificial anode 96 is preferably with the magnetic core 66 connected electrically conductive. The extent of the annular sacrificial anode 96 in the direction of the longitudinal axis 69 is less than the extension of the sleeve-shaped sacrificial anode 96 according to the first embodiment.

In 4 is the inlet valve 24 with the sacrificial anode 96 according to a third embodiment, wherein the sacrificial anode 96 in the region of the carrier element 78 arranged and annular. The carrier element 78 has an at least approximately frusto-conical portion 79 on, a cylindrical portion of the support element 78 of smaller diameter, on which the connecting element 92 is arranged, with a cylindrical portion of the support element 78 connects with larger diameter, the housing part 16 the pump is arranged. The sacrificial anode 96 according to the third embodiment is to the section 79 the carrier element 78 adapted also frustoconical and surrounds the section 79 at least on a part of its circumference, preferably over its entire circumference, and is connected to the section 79 connected electrically conductive.

In 5 is the inlet valve 24 with the sacrificial anode 96 according to a fourth embodiment, wherein the sacrificial anode 96 in the area of the magnetic core 66 is arranged. The sacrificial anode 96 is on the support element 78 remote end face of the magnetic core 66 arranged and disc-shaped. The sacrificial anode 96 is electrically conductive with the magnetic core 66 connected.

At an in 6 illustrated embodiment is the sacrificial anode 96 not executed as a form-containing component but in the form of a powder or granules in the space 94 brought in. The sacrificial anode 96 fills the gap 94 at least partially and is electrically conductive with the carrier element 78 and / or the connecting element 92 and / or the magnetic core 66 connected. The sacrificial anode 96 is in 6 symbolized by a multitude of points.

The function of the solenoid-operated intake valve will be described below 24 explained. During the suction stroke of the pump piston 12 is the inlet valve 24 opened by the valve member 34 in its open position, in this with its sealing surface 42 from the valve seat 40 is arranged remotely. The movement of the valve member 34 in its open position is characterized by the between the fuel inlet 26 and the Pump working space 18 prevailing pressure difference against the force of the valve spring 50 causes. The magnetic coil 64 of the actor 60 can be energized or de-energized. When the solenoid 64 energized is the magnet armature 68 by the resulting magnetic field against the force of the return spring 82 to the magnetic core 66 pulled out. When the solenoid 64 is not energized so is the armature 68 by the force of the return spring 82 to the inlet valve 24 pressed down. The magnet armature 68 is at least indirectly on the front side of the shaft 36 of the valve member 34 at.

During the delivery stroke of the pump piston 12 is through the actor 60 determines if the valve member 34 of the inlet valve 24 is in its open position or closed position. With de-energized magnetic coil 64 becomes the magnet armature 68 by the return spring 82 in the direction of adjustment according to arrow B in 2 pressed, the valve member 34 through the magnet armature 68 against the valve spring 50 in the direction of adjustment B is pressed in its open position. The force of the magnet armature 68 acting return spring 82 is greater than the force of the valve member 34 acting valve spring 50 , In the direction of adjustment B the magnet armature acts 68 on the valve member 34 and the magnet armature 68 and the valve member 34 become together in the direction of adjustment B emotional. As long as the solenoid 64 is not energized thus can by the pump piston 12 no fuel in the store 30 be promoted but from the pump piston 12 displaced fuel gets into the fuel feed 26 conveyed back. If during the delivery stroke of the pump piston 12 Fuel in the store 30 to be promoted so will the solenoid 64 energized, so that the magnet armature 68 to the magnetic core 66 in a direction to the direction B opposite direction of adjustment according to arrow A in 2 is pulled. Through the magnet armature 68 Thus, no more force on the valve member 34 exercised, the magnet armature 68 is moved by the magnetic field in the direction of adjustment A and the valve member 34 independent of the magnet armature 68 conditioned by the valve spring 50 and those between the pump work space 18 and the fuel feed 26 prevailing pressure difference in the direction of adjustment A is moved to its closed position.

By opening the inlet valve 24 during the delivery stroke of the pump piston 12 by means of the electromagnetic actuator 60 can the flow rate of the high-pressure pump in the store 30 be set variably. If a small fuel delivery is required then the inlet valve will become 24 through the actor 60 during a large part of the delivery stroke of the pump piston 12 kept open and if a large fuel delivery is required, then the inlet valve 24 only during a small part or not at all during the delivery stroke of the pump piston 12 kept open.

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 102015212390 A1 [0002]

Claims (8)

Electromagnetically actuated inlet valve (24) for a high-pressure pump, in particular a fuel injection system, having a valve member (34) movable between an open position and a closed position, with an electromagnetic actuator (60) through which the valve member (34) is movable the electromagnetic actuator (60) has a magnetic coil (64), a magnetic core (66) and an armature (68) acting at least indirectly on the valve member (34), in a receptacle (76) of a carrier element (78) in the direction of its longitudinal axis (69) is displaceably guided, wherein the magnetic core (66) and the carrier element (78) by a housing (70) are surrounded, characterized in that in the housing (70) in an intermediate space (94) between the housing (70) on the one hand and the carrier element (78) and / or the magnetic core (66) and / or a connecting element (92) interconnecting the magnetic core (66) and the carrier element (78), on the other hand at least one sacrificial anode (96) is arranged, which is electrically conductively connected to the carrier element (78) and / or the magnetic core (66) and / or the connecting element (92) and which consists of a less noble metal than the carrier element (78) and / or the magnetic core (66) and / or the connecting element (92). Inlet valve after Claim 1 , characterized in that the connecting element (92) by means of at least one welded joint (93) with the support member (78) and / or the magnetic core (66) is connected. Inlet valve after Claim 1 or 2 , characterized in that the at least one sacrificial anode (96) is at least approximately sleeve-shaped or annular and surrounds the carrier element (78) and / or the magnetic core (66) and / or the connecting element (92) on at least a part of the circumference. Inlet valve after Claim 1 or 2 , characterized in that the at least one sacrificial anode (96) on the support element (78) facing away from the end face of the magnetic core (66) is arranged and preferably at least approximately disc-shaped. Inlet valve according to one of the preceding claims, characterized in that the at least one sacrificial anode (96) inserted into the housing (70), in particular is pressed. Inlet valve after Claim 1 or 2 , characterized in that the at least one sacrificial anode (96) is introduced in powder or granular form in the intermediate space (94) and at least partially fills it. Inlet valve according to one of the preceding claims, characterized in that the at least one sacrificial anode (96) consists of magnesium or aluminum or an alloy containing magnesium or aluminum. Pump, in particular high-pressure fuel pump, with at least one pump element (10) having a pump working space (18) limiting pump piston (12), wherein the pump working space (18) via an inlet valve (24) with an inlet (26) is connectable, characterized in that the inlet valve (24) is designed according to one of the preceding claims.

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