DE102009046079A1 - Valve for quantity control of a fuel high pressure pump, comprises a valve element and a stop on which the valve element comes in opened condition in plant, and a damping device with a movable piston limiting a fluid chamber - Google Patents

Abstract

The valve for quantity control of a fuel high pressure pump, comprises a valve element (24) and a stop on which the valve element comes in opened condition in plant, a damping device with a movable piston (36) limiting a fluid chamber, a restrictor line flowing into the fluid chamber with a throttle point (48), and a stop plate, where the piston is arranged so that it is subjected by a valve element shortly before striking on the stop and fluid (34) is pressed from the fluid chamber by the throttle point, which comprises a annular gap. The valve for quantity control of a fuel high pressure pump, comprises a valve element (24) and a stop on which the valve element comes in opened condition in plant, a damping device with a movable piston (36) limiting a fluid chamber, a restrictor line flowing into the fluid chamber with a throttle point (48), and a stop plate, where the piston is arranged so that it is subjected by a valve element shortly before striking on the stop and fluid (34) is pressed from the fluid chamber by the throttle point, which comprises a annular gap between an outer surface of the piston and a wall of a piston guide. The piston comprises an axial hole by which the valve element is partially closed according to a type of a ball- or conical seat valve. The throttle point comprises a channel connected with the fluid chamber. The channel comprises an aperture. The damping device and the fluid chamber are arranged in a housing of the quantity control valve. The damping device and the fluid chamber are arranged in an anchor of the valve element. A spring is arranged between the piston and a wall of the fluid chamber so that it impacts the introduction of the piston through the valve element. The piston has a diameter step, which forms a stop pin. The channel connected with the fluid chamber comprises a diagonal hole formed to an axis of the valve element.

Description

State of the art

The invention relates to a quantity control valve according to the preamble of claim 1.

From the market known quantity control valves in fuel systems of internal combustion engines, in which hydraulic end position dampening are used. Thus, especially at low engine speeds, the operating noise can be reduced by a hitting an anchor-needle composite is damped at a stop. Reference is made to the following publications: DE 10 2007 034 038 A1 . DE 10 2007 028 960 A1 . DE 10 2005 022 661 A1 . DE 10 2004 061 798 A1 . DE 2004 016 564 A1 . DE 103 27 411 A1 . DE 198 34 121 A1 . EP 1 701 031 A1 . EP 1 471 248 A1 and EP 1 296 061 A2 ,

Disclosure of the invention

The problem underlying the invention is solved by a quantity control valve according to claim 1. Advantageous developments are specified in subclaims. Features which are important for the invention can also be found in the following description and in the drawings, wherein the features, both alone and in different combinations, can be important for the invention, without being explicitly referred to again.

The quantity control valve according to the invention has the advantage that the speed of a valve element (armature-needle composite) in an end phase of the valve lift - ie shortly before hitting a stop - is reduced. At the same time a "hydraulic bonding" of the valve element is at least reduced in a subsequent lifting of the stop.

A basic idea of the invention is to provide, by using a piston together with a fluid chamber, a damping device for a volume control valve, which has hydraulic throttle points. These may also be adapted to a particular type of quantity control valve in terms of their execution and / or attenuation.

The damping device of the quantity control valve basically works as follows: The moving valve element comes in the final phase of its movement (in particular an opening movement) in contact with the piston and exerts on this a pressure, whereby this in turn acts on a fluid located in the fluid chamber and it at least partially by a throttle point from the fluid chamber pushes out, resulting due to hydraulic losses, the desired damping in the form of a force directed against the movement. As a result, the movement of the valve element is braked, so that it has a comparatively low speed when reaching the stop. In a simple embodiment of the damping device, it is the valve element itself, which acts directly on the piston. The fluid is, for example, a fuel.

Another advantage of the invention is that the valve element no longer unrestrained meets the stop and thus the vibration excitation of a fuel pump is at least reduced. Thus, the noise is additionally favorably influenced. Likewise, the mechanical stress of the stop and the valve element decreases, so that the latter can optionally be performed with a smaller mass. Therefore, the solenoid may possibly be smaller, which can have a favorable effect on the electrical power loss. Furthermore, due to the reduced (final) speed of the valve element in the flow control valve occurring pressure pulsations can be reduced. The damping device according to the invention requires little or no additional space and can often be integrated into existing quantity control valves.

The quantity control valve is particularly easy to build if the throttle point is an annular gap between the piston and piston guide. In this way, fluid can be exchanged via the annular gap without special manufacturing processes or elements being required. Thus, the production of the quantity control valve is cheaper. It is also possible the arrangement of the throttle point in a channel-like recess in the wall and / or in the wall of the piston guide.

Furthermore, the piston can have an axial bore, which can be closed by the valve element. This results in the following sequence: The moving valve element strikes the piston, wherein it essentially closes the axial bore of the piston by means of, for example, a spherical or conical end section. As a result, the damping device initially acts as explained. If, in a subsequent phase, the valve element lifts off the stop again, the axial bore in the piston is released immediately and can thus accelerate the replacement of the fluid. Thus, the fluid chamber can be filled faster with the dead volume, and is ready for the next power stroke faster. In this way, the dynamics of the quantity control valve is advantageously increased. In addition, the spherical or conical End section allow or improve a centering of the valve element and the piston.

The throttle point of the quantity control valve can be reproduced more accurately if it has at least one channel connected to the fluid chamber. In this way, at the same time the influence of the fluid viscosity on the replacement of the fluid is reduced and expanded the application possibilities of the damping device. For example, the ratio of a channel cross-section to an outline characterizing the channel cross-section may be more favorable than with an annular gap. In this case, the channel can be made by a simple axial or radial bore, or by a combination of an axial and a radial bore, which intersect in a housing of the quantity control valve or in the valve element or in an anchor.

In addition, it is proposed that the channel has a diaphragm. This makes it possible to produce a cross section defining the throttle point defined.

A first basic form of the invention provides that the damping device and the fluid chamber are arranged in the housing of the quantity control valve. Thus, the damping device is arranged stationary in comparison to the valve element and as a whole does not participate in the movement thereof. In addition, the space available in the housing is comparatively large, so that the construction of the damping device is simplified.

A second basic form of the invention provides that the damping device and the fluid chamber are arranged in the valve element, for example in an armature of the valve element. Thus, the essential elements of the damping device in the valve element (anchor-needle composite) are united and permanently assigned. As a result, the effect can be optimally adapted to a present total mass of the valve element and the damping device. In addition, the housing of the quantity control valve is simpler.

The mass control valve works better when a spring between the piston and a wall of the fluid chamber is arranged so that it counteracts an impact of the piston by the valve element. Thus, the piston can be brought into a defined starting position, while the valve element is lifted from the piston. By the action of the spring force, the dynamics of the damping device is thus increased.

A further embodiment of the invention provides that the piston has a diameter step, which forms a stop pin. This results in at least two advantages: First, the piston is extended towards the valve element and can thus protrude defined beyond the stop. Second, a contact area formed between the piston and the valve element is reduced, thereby reducing hydraulic sticking effects as the valve element falls off in those types of flow control valve where there is fluid between the piston and the stopper and the valve element, respectively.

The quantity control valve is easier to construct if the channel connected to the fluid chamber comprises at least one oblique bore formed relative to an axis of the valve element. Due to the oblique bore, the fluid chamber can be connected in a simple manner with the valve volume without, for example, two mutually perpendicular and intersecting channels must be drilled. This simplifies manufacturing and reduces manufacturing costs.

The throttle point, through which the fluid is pressed through, can also be realized by any combination of multiple throttle bodies, ie from the annular gap, the axial bore, an axial channel, a radial channel and / or the oblique bore.

A further embodiment of the invention provides that the quantity control valve has a stop plate which limits a movement of the piston. If the valve element is lifted, the spring acts on the piston between the piston and the wall of the fluid chamber and displaces it against the stop plate. As a result, the piston can be brought into a defined starting position. In this case, the side facing away from the piston of the stop plate form at least a part of the stop on which the valve element comes into contact in the open state.

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

1 a simplified diagram of a fuel system of an internal combustion engine;

2 a schematically illustrated first basic form and at the same time first embodiment of a quantity control valve;

3 one to 2 similar second embodiment;

4 one to 2 similar third embodiment;

5 one to 2 similar fourth embodiment;

6 a schematically illustrated second basic form and at the same time fifth embodiment of a quantity control valve; and

7 one to 6 similar sixth embodiment.

The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments. Likewise, these are not rewritten each time.

1 shows a fuel system 1 an internal combustion engine in a much simplified representation. A (not explained in detail) high-pressure pump 3 is upstream via a suction line 4 , a prefeed pump 5 and a low pressure line 7 with a fuel tank 9 connected. Downstream is to the high pressure pump 3 via a high pressure line 11 a high-pressure accumulator 13 ("Common rail") connected. A quantity control valve 14 with an electromagnet 15 is hydraulically between the low pressure line 7 and the high pressure pump 3 arranged. Other elements, such as high-pressure pump valves 3 , are in the 1 not drawn. It is understood that the quantity control valve 14 as a unit with the high-pressure pump 3 can be trained. For example, by the quantity control valve 14 an inlet valve of the high pressure pump 14 be forced open. In addition, the quantity control valve 14 also have a different actuator than an electromagnet, such as a piezoelectric actuator or a hydraulic actuator.

When operating the fuel system 1 promotes the pre-feed pump 5 Fuel from the fuel tank 9 in the low pressure line 7 , The quantity control valve determines 14 the high pressure pump 3 amount of fuel supplied.

2 shows very schematically and simplifies some elements of a quantity control valve 14 , The elements have a substantially radially symmetric structure. In the left part of the drawing 2 is a valve element 24 comprising a valve needle 25 and an anchor firmly connected thereto 26 shown. Opposite lying in the right part of the drawing is an associated Polkern 28 together with a damping device 30 , The anchor 26 and the polkernel 28 are elements of the in the 1 represented electromagnet 15 , Here is the Polkern 28 either part of a (in the 2 not shown) housing 31 of the quantity control valve 14 , or he is at least associated with this.

The damping device 30 includes a fluid chamber 32 in which a fluid 34 and a spring designed as a helical spring 38 available. The fluid chamber 34 becomes the valve element 24 through a piston 36 limited. The piston 36 has a diameter step, whereby a stop pin 40 is formed, which in the drawing to the left from an opening 42 a stop plate 44 protrudes. The stop plate 44 forms at least part of the anchor 26 facing outer surface 45 of the pole core 28 , and has the function of a stop 46 , In the at least temporarily between the anchor 26 and the pole core 28 existing space is also the fluid 34 ,

The feather 38 pushes the piston 36 in the drawing to the left to the stop plate 44 out, so that the stop pin 40 in the operating situation shown maximum from the opening 42 protrudes. This gives the damping device 30 at the same time a defined initial position.

When energizing the electromagnet 15 the anchor moves 26 together with the valve needle 25 by magnetic force on the pole core 28 in the drawn x-direction. Just before hitting the stop 46 comes the valve element 24 in contact with the stop pin 40 of the piston 36 , causing the piston 36 against the action of the spring 38 is charged. The following is the piston 36 doing in the drawing to the right against the force of the spring 38 moves, causing the pressure of the fluid 34 in the fluid chamber 32 elevated. As a result of the pressure increase, the fluid 34 through one between the piston 36 and a wall of the fluid chamber 32 formed annular gap 48 pressed, the extent a throttle point 48 forms for the outflowing fluid, and flows in a to the left of the piston in the drawing 36 located volume range. The flow of the fluid 34 through the comparatively narrow annular gap 48 causes hydraulic losses, resulting in a corresponding mechanical damping or slowing down the movement of the valve element 24 results.

Will the power supply of the electromagnet 15 interrupted, so the valve element 24 So the valve needle 25 together with the anchor 26 moved by a spring, not shown, against the drawn x-direction, so that between the anchor 26 and the pole core 28 again forms a gap. This allows the spring 38 now the piston 36 back against the stop plate 44 and press it into the starting position. Because of the comparatively low force of the spring 38 and because of the over the annular gap 48 back flowing fluid 34 this process is relatively slow. Thereafter, the damping device 30 ready for the next cycle.

3 shows one to the 2 comparable arrangement. However, the piston points 36 including the stopper pin 40 a continuous axial and central bore 50 on. In addition, located at the right in the drawing, the valve element 24 a cone-shaped approach 52 which is sized to be the axial bore 50 can close in the sense of a cone seat valve. The other elements correspond to those of 2 ,

When energizing the electromagnet 15 (please refer 1 ) the anchor moves 26 together with the valve element 24 in one to the 2 comparable way to the stop 46 to. Upon impact of the valve element 24 on the stop pin 40 becomes the axial bore 50 through the cone-shaped approach 52 closed fluid-tight, so that the rest of the movement according to the 2 expires.

Will the power supply of the electromagnet 15 interrupted, so the valve element 24 again moves against the drawn x-direction, so that between the anchor 26 and the pole core 28 again forms a gap. At the same time, the axial bore 50 Approved. This allows the fluid chamber 32 fast again with fluid 34 be filled from the volume range or space. The one in the drawing to the left of the piston 36 located volume range, which now by the piston movement steadily back from the piston 36 is largely emptied through the opening 42 in the gap. This is easily possible provided the opening 42 the stop pin 40 surrounds with a sufficient distance, leaving enough fluid 34 can flow through. Thus, the output state of the damper becomes 30 conditioned by the axial bore 50 reached quickly.

4 shows one to the 2 comparable damping device 30 in which an exchange of the in the fluid chamber 32 located fluid 34 can be done by means of two channels. Essentially, only the differences from the previous figures are explained. The Polkern 28 each has an axial 54 and radial channel 56 on which is within the polkernel 28 cross, so are fluidly connected. The radial channel 56 is present at its end 60 closed, whereas the axial channel 54 a panel 48 having. By means of the aperture 48 is set a defined flow cross-section, the aperture 48 thus forms a throttle point 48 for the outflowing fluid. The replacement of the fluid 34 takes place here at the stop 46 forming side of the pole core 28 ,

Both when an impact on the piston 36 , as well as at a discharge, the fluid 34 through the two channels 54 and 56 stream and one compared to 2 bring about rapid pressure equalization. In particular, the influence of the viscosity of the fluid is also 34 reduced, whereby the application possibilities are extended. This is especially true when the aperture 48 Depending on the flow direction provides a different strong throttling (strong throttling for outflowing fluid, low throttling for back-flowing fluid).

5 shows a modification of the damping device 30 after 4 , where the two channels 54 and 56 through an oblique hole 62 are replaced. Also present is an aperture 48 effective. To illustrate the many possibilities is additionally an axial bore 50 existing, whose structure and function already in the 3 has been described.

6 shows a further embodiment of the quantity control valve 14 in which the damping device 30 not in the pole core 28 but in the anchor 26 is housed. A radial channel 56 allows together with a shutter 48 the replacement of the fluid 34 , The Polkern 28 contains no elements of the damping device 30 , but forms - besides its magnetic function - only the stop 46 , An advantage of the present embodiment is that the aperture 48 optionally structurally simpler can be designed.

Unlike the ones in the 2 to 5 shown embodiments in the 6 the damping device 30 together with the anchor 26 emotional. Regarding the relative motion of anchor 26 and polkernels 28 changes little, leaving the function of the damping device 30 essentially the same remains.

7 shows a comparable embodiment in principle to the 6 wherein the fluid exchange in both directions of the piston movement across the annular gap 48 takes place, as well as relieving the damping device 30 additionally via the axial bore 50 as it was already at the 3 has been described. The approach 52 with which the axial bore 50 is closed in the manner of a ball or conical seat valve is in this case on the pole core 28 arranged.

It is understood that in the 2 to 7 shown embodiments of the damping device 30 can be combined as desired.

Furthermore, the damping device 30 Generally not limited to quantity control valves, but suitable for many valve applications, in which the end position of an axially displaceable element on a stop 46 should be damped. Starting from the representations of the 2 to 7 the damping device works 30 similarly good if the anchor 26 and the polkernel 28 do not assume a magnetic function, but are merely constructive elements of a particular application. These can also be geometrically adjusted and, for example, reduced in size. In addition, if necessary, by using two damping devices 30 Both end positions of an axially displaceable element are damped. It must be the same with the fluid 34 not be a fuel such as gasoline or diesel act, but it can be used arbitrarily other liquids with different viscosities.

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 102007034038 A1 [0002]
• DE 102007028960 A1 [0002]
• DE 102005022661 A1 [0002]
• DE 102004061798 A1 [0002]
• DE 2004016564 A1 [0002]
• DE 10327411 A1 [0002]
• DE 19834121 A1 [0002]
• EP 1701031 A1 [0002]
• EP 1471248 A1 [0002]
• EP 1296061 A2 [0002]

Claims (11)

Quantity control valve ( 14 ), in particular for controlling the quantity of a high-pressure fuel pump ( 3 ), with a valve element ( 24 ) and a stop ( 46 ), on which the valve element ( 24 ) comes into abutment in the opened state, characterized in that it has a damping device ( 30 ) with a fluid chamber ( 32 ) limiting movable piston ( 36 ) and an opening into the fluid chamber throttle line with a throttle point ( 48 ), wherein the piston ( 36 ) is arranged so that it from the valve element ( 24 ) shortly before hitting the attack ( 46 ) and so fluid ( 34 ) from the fluid chamber ( 32 ) through the restriction ( 48 ) is pushed through. Quantity control valve ( 14 ) according to claim 1, characterized in that the throttle point ( 48 ) an annular gap ( 48 ) between a lateral surface of the piston ( 36 ) and a wall of a piston guide. Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that the piston ( 36 ) an axial bore ( 50 ), which through the valve element ( 24 ) is closed at least partially, and preferably in the manner of a ball or cone seat valve. Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that the throttle point ( 48 ) at least one with the fluid chamber ( 32 ) connected channel ( 54 . 56 ; 62 ). Quantity control valve ( 14 ) according to claim 4, characterized in that the channel ( 54 . 56 ; 62 ) an aperture ( 48 ) having. Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that the damping device ( 30 ) and the fluid chamber ( 32 ) in a housing ( 31 ) of the quantity control valve ( 14 ) are arranged. Quantity control valve ( 14 ) according to at least one of claims 1 to 5, characterized in that the damping device ( 30 ) and the fluid chamber ( 32 ) in the valve element ( 24 ), preferably in an anchor ( 26 ) of the valve element ( 24 ) are arranged. Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that a spring ( 38 ) between the piston ( 36 ) and a wall of the fluid chamber ( 32 ) is arranged so that it an admission of the piston ( 36 ) through the valve element ( 24 ) counteracts. Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that the piston ( 36 ) has a diameter step which a stop pin ( 40 ). Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that the with the fluid chamber ( 32 ) connected channel ( 54 . 56 ; 62 ) at least one to an axis of the valve element ( 24 ) formed oblique bore ( 62 ). Quantity control valve ( 14 ) according to at least one of the preceding claims, characterized in that it has a stop plate ( 44 ), which movement of the piston ( 36 ) limited.

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