DE102014220975A1 - Electromagnetically actuated inlet valve and high-pressure pump with inlet valve - Google Patents

Abstract

The invention relates to an electromagnetically operable inlet valve (22) for a high pressure pump, in particular a fuel injection system, with a valve member (34) which is movable between an open position and a closed position. The valve member (34) comes in its closed position on a valve seat (50) as a stop to the plant. The valve member (34) is movable by an electromagnetic actuator (56), wherein the electromagnetic actuator (56) has a force acting on the valve member (34) armature (62). The magnet armature (62) acts on the valve member (34) only in a first adjustment direction (A), and the valve member (34) and the magnet armature (62) are movable independently of one another in an opposite second adjustment direction (B).

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, in particular a radial or in-line piston pump for a fuel injection system, is characterized by the DE 10 2010 027 745 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 is arranged in a recess of a housing part of the high-pressure pump designed as a cylinder head and is fixed in position by means of a screw plug screwed into the cylinder head. The inlet valve comprises a valve housing and a valve member which cooperates with a valve seat formed on the valve housing for control. The valve member is acted upon by a valve spring in the closing direction. Furthermore, the inlet valve comprises an electromagnetic actuator, through which the valve member is movable. The electromagnetic actuator has a solenoid formed as a plunger armature, which is connected to the valve member, and a magnetic coil to generate a force acting on the armature magnetic field when the solenoid is energized. The armature and the valve member are connected together and form a structural unit which is moved together, whereby it has a large mass. In particular, during the closing movement of the valve member when it comes to rest on the valve seat as a stop thereby act large forces that can lead to wear and damage of the valve member and / or the valve seat. In addition, this is associated with a strong noise and the dynamics of the intake valve, that is, the switching speed between the open and closed position is deteriorated.

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 armature acts only in the first to be effected by the armature first actuating direction of the valve member, while in the opposite second direction of adjustment no connection between the armature and valve member is present and thus only the individual masses are moved and come to a stop to the plant. This reduces the risk of wear and damage and noise and improves the dynamics of the intake valve.

In the dependent claims advantageous refinements and developments of the inlet valve according to the invention are given. The embodiment according to claim 3, an independent provision of the armature and the valve member in the second direction of adjustment is possible. The embodiment according to claim 5 allows a low-wear guidance of the magnet armature. The embodiment according to claim 7 or 8 allows a low weight and thus high dynamics of the armature.

Furthermore, a high-pressure pump with an inlet valve according to the invention for connecting a pump working chamber of the high-pressure pump with a fuel feed is proposed. The inlet valve is inserted into a housing part of the high-pressure pump.

drawing

An embodiment of the invention will be described below with reference to the accompanying drawings. Show it 1 a schematic longitudinal section through a high-pressure pump and 2 in an enlarged view a in 1 Section II with the inlet valve of the high-pressure pump.

Description of the embodiment

In 1 is a 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 is guided and in the cylinder bore 14 a pump workroom 16 limited. As a drive for the pump piston 12 can be a drive shaft 18 with a cam 20 or eccentric be provided on which the pump piston 12 directly or via a plunger, for example a roller tappet, supported. The pump workroom 16 is via an inlet valve 22 with a fuel feed 21 connectable and via an outlet valve 24 with a memory 26 , The inlet valve 22 is for example in a hole 27 a housing part 28 used the high pressure pump. During the suction stroke of the pump piston 12 can the pump work space 16 with the inlet valve open 22 With Fuel to be filled. During the delivery stroke of the pump piston 12 gets out of the pump workspace by this fuel 16 displaced and in the memory 26 promoted.

This in 2 enlarged illustrated inlet valve 22 has a valve housing 30 in, where in a hole 32 a piston-shaped valve member 34 is movably guided. Into the hole 32 of the valve housing 30 opens at least one, preferably a plurality of radial bores 36 in hydraulic communication with the fuel inlet 21 stand. At the height of the radial bores 36 can the valve body 30 from a sieve element 38 be surrounded to prevent any particles contained in the fuel in the inlet valve 22 and into the pump work space 16 reach. The valve housing 30 is directly or via a sealing washer 40 on a heel 29 the bore 27 in the pump housing part 28 supported to the pump work space 16 To seal against the fuel inlet. An axial contact pressure of the valve housing 30 is for example via a screw plug 42 causes the into the hole 27 of the pump housing part 28 screwed in and on the valve body 30 is supported.

The valve member 34 points at his into the pump workspace 16 protruding end a head 44 with opposite the shaft 46 of the valve member 34 larger diameter. On the shaft 46 facing side is on the head 44 an annular sealing surface 48 formed, with the valve member 34 with one at the edge of the hole 32 on the valve body 30 trained valve seat 50 interacts. The valve member 34 stands out with its the pump workroom 16 opposite end region of the bore 32 of the valve housing 30 out and at the end area is supported by a spring plate 52 a valve spring 54 from, through which the valve member 34 is acted upon in the closing direction. In its closed position lies the valve member 34 with its sealing surface 48 sealing at the valve seat 50 so that the pump workspace 16 is separated from the fuel inlet.

The inlet valve 22 is by an electromagnetic actuator 56 actuated. The actor 56 is by an electronic control device 86 triggered depending on operating parameters of the engine to be supplied. The electromagnetic actuator 56 has a magnetic coil 58 , a magnetic core 60 and a magnet armature 62 on. The electromagnetic actuator 56 is on the pump work space 16 opposite side of the inlet valve 22 arranged. The magnetic core 60 and the magnetic coil 58 are in a housing part 64 arranged with the screw plug 42 connected is. The magnet armature 62 is at least substantially cylindrical and formed over its outer shell in a bore 66 in the screw plug 42 slidably guided. The hole 66 in the screw plug 42 runs at least approximately coaxial with the bore 32 in the valve housing 30 , In his the intake valve 22 facing end region, the magnet armature 62 in a central area on a recording, for example, as a blind hole 68 is formed and in the one from the end portion of the valve member 34 protruding pin 35 protrudes. The pin 35 is in the blind hole 68 arranged with radial clearance, so that the valve member 34 with respect to the magnet armature 62 is mobile. The pin 35 can with his in the blind hole 68 lying front end at the bottom of the blind hole 68 in the magnet armature 62 come to the plant.

For weight reduction of the magnet armature 62 this points between the central area with the blind hole 68 and its outer shell at least one recess 70 on. Preferably, the recess surrounds 70 the central area with the blind hole 68 over its entire circumference. The magnet armature 62 also has one of the inlet valve 22 opposite side of the armature 62 outgoing further blind hole 72 on top of the blind hole 68 is separated and at least approximately coaxial with the blind hole 68 runs. The further blind hole 72 can with the recess 70 over one or more radial or oblique holes 74 be connected. The from the inlet valve 22 groundbreaking end of the further blind hole 72 has a larger diameter than the remaining area, whereby one to the end face of the armature 62 pointing ring shoulder 76 is formed. At the ring shoulder 76 a return spring is supported 78 for the magnet armature 62 on the other hand, at least indirectly on the housing part 64 is supported. In the hole 66 is by a diameter reduction between the armature 62 and the inlet valve 22 an annular shoulder 80 formed a stop for the armature 62 for limiting its movement to the inlet valve 22 forms.

The function of the solenoid-operated intake valve will be described below 22 explained. During the suction stroke of the pump piston 12 is the inlet valve 22 opened by the valve member 34 in its open position, in this with its sealing surface 48 from the valve seat 50 is arranged remotely. The movement of the valve member 34 in its open position is characterized by the between the fuel inlet 21 and the pump work space 16 prevailing pressure difference against the force of the valve spring 54 causes. The magnetic coil 58 of the actor 56 can be energized or de-energized. When the solenoid 58 energized is the magnet armature 62 by the resulting magnetic field against the force of the return spring 78 to the solenoid 58 pulled out. If the solenoid 58 is not energized so is the armature 62 by the force of the return spring 78 to the inlet valve 22 pressed down and in contact with the ring shoulder 80 held.

During the delivery stroke of the pump piston 12 is through the actor 56 determines if the valve member 34 of the inlet valve 22 is in its open position or closed position. With de-energized magnetic coil 58 becomes the magnet armature 62 by the return spring 78 in a first direction of adjustment according to arrow A in 2 in contact with the ring shoulder 80 pressed, the valve member 34 through the magnet armature 62 against the valve spring 54 is pressed in its first position in its open position. The force of the magnet armature 62 acting return spring 78 is greater than the force of the valve member 34 acting valve spring 54 , In the first adjustment direction A, the armature acts 62 on the valve member 34 and the magnet armature 62 and the valve member 34 are moved together in the first adjustment direction A. As long as the solenoid 58 is not energized thus can by the pump piston 12 no fuel in the store 26 be promoted but from the pump piston 12 displaced fuel gets into the fuel feed 21 conveyed back. If during the delivery stroke of the pump piston 12 Fuel in the store 26 to be promoted so will the solenoid 58 energized, so that the magnet armature 62 to the solenoid 58 in a direction opposite to the first direction A second adjustment direction according to arrow B in 2 is pulled. Through the magnet armature 62 Thus, no more force on the valve member 34 exercised, the magnet armature 62 is moved by the magnetic field in the second direction of adjustment B and the valve member 34 independent of the magnet armature 62 conditioned by the valve spring 54 and those between the pump work space 16 and the fuel feed 21 prevailing pressure difference in the second direction of adjustment B is moved to its closed position. By opening the inlet valve 34 during the delivery stroke of the pump piston 12 by means of the electromagnetic actuator 56 can the flow rate of the high-pressure pump in the store 26 be set variably. If a small fuel delivery is required then the inlet valve will become 34 through the actor 56 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 34 only during a small part or not at all during the delivery stroke of the pump piston 12 kept open.

Upon impact of the valve member 34 with its sealing surface 48 on the valve seat 50 as a stop in the second direction of adjustment B is thus only the mass of the valve member 34 itself authoritative, resulting in only a small load on the valve member 34 and the valve seat 50 results. It can be provided that the magnet armature 62 in the second adjustment direction B also comes to a stop to the plant, for example, by a between the magnetic core 60 and the armature 62 arranged residual air gap disc 82 can be formed. In addition, it can be provided that the movement of the magnet armature 62 in the second direction B shortly before reaching the stop 82 is damped, so that the impact velocity of the armature 62 at the stop 82 is reduced. The damping of the magnet armature 62 can be done hydraulically by the armature 62 in a fuel-filled room 84 submerges, from which only via a throttled drain fuel when immersing the armature 62 can flow out. An attenuation of the movement of the valve member 34 in the second direction of adjustment B to its closed position should not occur, as a rapid closing of the inlet valve 34 important for the function of the high-pressure pump. To make this possible, the armature leads 62 in the second direction of adjustment B, a larger stroke than the valve member 34 and a damping of the armature 62 takes place only with a larger path of movement in the second direction of adjustment B than the path of movement of the valve member 34 until it has reached its closed position.

QUOTES INCLUDE IN THE DESCRIPTION

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Cited patent literature

• DE 102010027745 A1 [0002]

Claims (9)

Electromagnetically actuated inlet valve ( 22 ) for a high pressure pump, in particular a fuel injection system, with a valve member ( 34 ) which is movable between an open position and a closed position, wherein the valve member ( 34 ) in its closed position on a valve seat ( 50 ) comes as a stop to the plant, with an electromagnetic actuator ( 56 ), through which the valve member ( 34 ) is movable, wherein the electromagnetic actuator ( 56 ) one on the valve member ( 34 ) acting armature ( 62 ), characterized in that the magnet armature ( 62 ) only in a first adjustment direction (A) on the valve member ( 34 ) and that the valve member ( 34 ) and the magnet armature ( 62 ) are movable independently of one another in an opposite second setting direction (B). Inlet valve according to claim 1, characterized in that the first adjusting direction (A) the direction of movement of the valve member ( 34 ) is in its open position. Inlet valve according to claim 1 or 2, characterized in that the valve member ( 34 ) and the magnet armature ( 62 ) by acting on these separate return springs ( 54 . 78 ) and that the valve member ( 34 ) acting on return spring ( 54 ) the valve member ( 34 ) is acted upon in the second adjusting direction (B) to its closed position. Inlet valve according to claim 3, characterized in that the magnet armature ( 62 ) by the return spring acting on this ( 78 ) is acted upon in the first actuating direction (A) and by energizing the electromagnetic actuator ( 56 ) against the force of the return spring ( 78 ) is movable in the second adjusting direction (B). Inlet valve according to one of the preceding claims, characterized in that the magnet armature ( 62 ) is at least substantially cylindrical and formed over its outer shell in a housing part ( 42 ) is guided displaceably. Inlet valve according to claim 5, characterized in that the valve member ( 34 ) a pin ( 35 ), which in one in a central region of the magnet armature ( 62 ) trained recording ( 68 ) protrudes. Inlet valve according to claim 6, characterized in that between the central region and the outer jacket of the magnet armature ( 62 ) at least one recess ( 70 ) is provided. Inlet valve according to claim 7, characterized in that the recess ( 70 ) the central area of the magnet armature ( 62 ) is formed surrounding over its entire circumference. High pressure pump with an inlet valve ( 22 ) according to one of the preceding claims for connecting a pump working space ( 16 ) of the high pressure pump with an inlet for medium to be conveyed, wherein the inlet valve ( 22 ) in a housing part ( 28 ) of the high pressure pump is used.

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