DE10348923A1 - Valve for controlling fluids - Google Patents

Abstract

A valve for controlling fluids is proposed. The valve has a valve body in which a particular piezoelectric actuator unit (23) for actuating a guided in the valve body valve member (24) is arranged. The valve member (24) comprises at least one in a valve chamber (22) arranged valve closing member (27) which cooperates with a first valve seat (30) and a second valve seat (33). The valve closing member (27) abuts against the first valve seat (30) in a first end position and against the second valve seat (33) in a second end position. According to the invention, a Zwischenhubanschlag (35) is provided, which defines a center position of the valve closing member (27) and on the valve closure member (27) engages (Figure 1).

Description

The The invention relates to a valve for controlling fluids according to the Preamble of claim 1 further defined type.

Such a valve is for example from the DE 100 55 714 A1 known and may be part of a fuel injector of a motor vehicle internal combustion engine.

One such injector may in particular be a common rail accumulator injection system for a diesel engine be assigned. The valve then serves as a control module for an in a nozzle module the injector arranged nozzle needle, the with openings or nozzles cooperates, which lead to a combustion chamber of the internal combustion engine and the fuel is injected into the combustion chamber. The control of the nozzle needle takes place in such a way that a fluid pressure is regulated by means of the control module is, in a so-called valve control chamber of the nozzle module prevails. Dependent on of the prevailing in the valve control chamber fluid pressure can Location of the nozzle needle changed and thus an injection of fuel into the combustion chamber are triggered.

Around apply an alternating pressure to the valve control chamber can, he is on the one hand over a so-called inlet throttle with a fuel supply line and then again a so-called drain throttle connected to the control module. The Control module comprises a piezoelectric actuator for actuating a in a valve body out Valve member is used, which comprises a arranged in a valve chamber valve closure member. The valve closure member cooperates with a first valve seat and a second valve seat, being an actuation of the valve closure member through an operation the piezoelectric actuator is triggered. The valve closing member locks when abutting the first valve seat or the second valve seat a fuel flow from the valve control chamber of the nozzle module through the drain throttle to a formed in the control module Return channel. In a position between the two end positions of the Valve closing member there is a pressure reduction in the valve control chamber, resulting in an axial Displacement of the nozzle needle and a release leading to the combustion chamber of the internal combustion engine Nozzles leads, so that fuel is injected into the combustion chamber.

In this intermediate or middle position between the two valve seats tends the known valve closure member but disadvantageously too strong vibrations. This in turn leads to vibrations in the combustion chamber of the internal combustion engine injected fuel amount, which is undesirable to avoid is.

Advantages of invention

The inventive valve for controlling to fluids with the features according to the preamble of claim 1, at which valve a Zwischenhubanschlag is provided, the one Center position of the valve closure member determines and acts on the valve closure member has the advantage that by the Zwischenhubanschlag possibly in the middle position the valve closure member occurring vibrations of the valve closure member in an effective manner muted can be. The tendency of the valve closure member in the center position can thus greatly reduced or even canceled.

The Valve according to the invention may in particular be part of a fuel injection valve of a Internal combustion engine and is in this case as a control module for a nozzle module with a nozzle needle designed. The intermediate stroke stop then causes vibrations in the means of the fuel injection valve in a combustion chamber injected fuel quantity are minimized.

The Valve according to the invention especially as a 3/3-valve be educated. In this case, the valve is also suitable for Control of a so-called coaxial vario nozzle, in which two coaxially arranged nozzle needles are driven can and each of the two nozzle needles for controlling at least one injection nozzle is used.

The Valve according to the invention may be in such an embodiment, for example be controlled so that in a first switching position, in which the valve closure member the valve bears against the first valve seat, both nozzle needles in closed position are located. In a second switching position, in which the valve closing member of Valve is applied to the second valve seat, is in a control the control room of one of the nozzle needles relieved, so that the nozzle needle in question opens. In a third switching position, which represents the middle position in which the closing member the intermediate stroke stop is applied, then takes place in this control Relief of both control rooms, what an opening both nozzle needles is reached. In this way is a stepped control of the fuel injection valve possible with regard to the injected fuel quantity.

In an alternative embodiment of the valve according to the invention as a 3/3-valve, ie with three When used with a fuel injection valve as an infeed line, the valve may comprise an outlet passage equipped with a drain throttle branching from a valve control space serving to control a nozzle needle, and having a bypass passage which also communicates with a throttle may be provided and branches off from a fuel supply line, is passed through the fuel in the injection valve and to injection nozzles of the injection valve.

When laxative Line can be a return channel be provided, which leads to a fuel tank.

In order to the valve closure member take advantage of his entire stroke can, d. H. between the first valve seat and the second valve seat is freely movable, the Zwischenhubanschlag is in an expedient embodiment of the valve according to the invention slidably mounted and biased by a spring. The feather then counteracts the force coming from the actuator unit exercised the piston becomes.

Of the Zwischenhubanschlag can be annular his and as a camp for a return spring serve, which the valve closing member biased in the direction of the first valve seat. In this case is the Zwischenhubanschlag biasing spring with a spring constant provided, which is larger as the spring constant of the return spring for the Valve closure member.

In order to the intermediate stroke stop a defined position in the valve chamber occupies, he acts expediently with a serving as a stop paragraph of the valve body together.

Further Advantages and advantageous embodiments of the subject to The invention are the description, the drawings and the claims removed.

drawing

Two embodiments of the valve according to the invention are schematic in the drawing simplified and will be described in the following description explained in more detail. It demonstrate

1 a highly simplified partial cross-sectional view of a control module according to the invention executed in a fuel injection valve; and

2 a schematic diagram of an alternative embodiment of an inventively executed control module in a fuel injection valve, also in a fragmentary longitudinal section illustration.

description the embodiments

In 1 is an injector 1 shown, which is part of a so-called commmon rail injection system and is used for injection of fuel into a combustion chamber of a diesel engine of a motor vehicle. The injection valve 1 includes for this purpose as essential components a valve-like design valve control module 2 and a nozzle module 3 ,

The nozzle module 3 is designed as a so-called coaxial Vario nozzle and has for this purpose one of an inner nozzle needle 4 and an outer nozzle needle 5 formed needle unit. The outer nozzle needle 5 serves to control a first row of injectors leading to a combustion chamber of the internal combustion engine, and the inner nozzle needle serves to control a second series of injection openings leading to the combustion chamber of the internal combustion engine. The coaxially arranged nozzle needles 4 and 5 are arranged side by side in the drawing for the sake of clarity.

For controlling or for actuating the nozzle needles, the nozzle module 3 two valve control rooms 13 and 14 on, with the valve control room 13 the inner nozzle needle 4 and the valve control room 14 the outer nozzle needle 5 assigned. The actuation of the nozzle needles 4 and 5 takes place via an adjustment of the pressure conditions in the valve control chambers 13 and 14 ,

The valve control rooms 13 and 14 are each via an inlet throttle 15 respectively. 16 with a fuel supply line 17 connected and so fueled. Furthermore, the valve control rooms 13 and 14 for reducing the prevailing fuel pressure in each case via one with an outlet throttle 18 respectively. 19 provided drain channel 20 respectively. 21 with a valve chamber 22 of the valve control module 11 connected. The outlet throttles 18 and 19 have a larger diameter than their respective assigned inlet throttle 15 respectively. 16 ,

About the fuel supply line 17 injects fuel intended for injection into the fuel injection valve 10 or guided to the injection nozzles, which lead to the combustion chamber of the internal combustion engine. The fuel supply line 17 stands for this purpose with a high-pressure accumulator common to several injectors, a so-called common rail, not shown here, in conjunction, so that in the fuel supply line 17 Guided fuel under a common rail systems over union high pressure of, for example, up to 1.5 kbar can stand.

For setting an injection start, an injection duration and an injection amount includes the injection valve 10 the valve control module 2 , which is a here schematically indicated and not to scale mapped, designed as a piezoelectric actuator actuator 23 having. The actuator unit 23 acts on a valve member 24 located in a valve body of the valve control module 11 is guided and a first, referred to as actuator piston 25 and a second piston, referred to as an actuating piston 26 having, for actuating a valve closure member 27 serves.

The actuation of the actuating piston 26 via a hydraulic coupler 28 , which is designed as a hydraulic chamber and an axial deflection of the means of the piezoelectric actuator 23 moved actuating piston 25 on the actuating piston 26 transfers. The hydraulic transmission causes the actuating piston 26 makes a stroke increased by the gear ratio of the piston diameter when the actuator piston 25 that has a larger diameter than the actuating piston 26 comprises, by means of the piezoelectric actuator 23 a certain distance is traversed.

The valve closure member 27 that in the valve room 22 is arranged, is formed substantially mushroom-shaped and acts on an approximately hemispherical shaped head area 29 with a first, designed as a conical seat valve seat 30 and over a free end face 31 a shaft area 32 with a second, designed as a flat seat valve seat 33 together.

The distance that the valve closing member 15 between the first valve seat 30 and the second valve seat 33 can be moved, represents the total stroke H ges of the valve closure member 27 or of the actuating piston 26 represents.

To establish a center position, the valve closure member 27 in the shaft area 32 a ring collar 34 on, the one with a Zwischenhubanschlag performing annular disc 35 interacts with one another at a paragraph 36 the valve body rests. The annular disc is by means of a spring designed here as a spiral spring 37 in the direction of the paragraph 36 biased. The spiral spring 37 is supported on the valve body. The intermediate stroke stop ring washer 35 is arranged so that in its rest position, a stroke H m of the valve closure member 27 and thus determines its middle position.

The ring disk 35 further serves to support a return spring which is likewise designed here as a helical spring 38 on the head area 29 the valve closure member 27 acts and the valve closure member 27 with unactuated piezoelectric actuator 23 against the first valve seat 30 presses and holds in locked position. The spring force of the return spring 38 is less than the spring force of the biasing spring 37 ,

Downstream of the first valve seat 30 is in the valve body of the valve control module 2 a return room 39 formed, from which a not shown here return channel branches off, which leads to a fuel tank also not shown here.

This in 1 illustrated fuel injection valve 1 works in the manner described below.

With unactuated piezoelectric actuator 23 lies the valve closure member 27 over his head area 29 at the first valve seat 30 at. In this position builds in the valve control rooms 13 and 14 of the nozzle module 12 in the fuel supply line 17 prevailing pressure, ie the rail pressure on. This is the inner nozzle needle 4 and the outer nozzle needle 5 each in its closed position, so that no fuel is injected via the respective associated injection nozzles in the combustion chamber of the internal combustion engine.

Now if the valve closure member 27 by actuation of the piezoelectric actuator 23 with his face 31 against the second valve seat 33 is driven, the Zwischenhubanschlag 35 overridden, ie from the paragraph 36 the Ven tilkörpers against the spring force of the biasing spring 37 lifted. In this position of the valve closure member 27 is the drainage channel 21 of the valve control room 14 locked so that in the valve control room 14 Furthermore, the rail pressure prevails and the associated inner nozzle needle remains in the closed position. However, fuel flows out of the valve chamber 22 over the return room 39 to the return passage and the fuel storage tank, so that the valve control room 13 over the outlet throttle 18 or the drainage channel 20 relieved and with the valve control room 13 cooperating, outer nozzle needle 5 is raised. The respective injection nozzles are thus released, and fuel is injected into the combustion chamber of the internal combustion engine.

Now if the piezoelectric actuator 23 is partially relieved, the valve closing member 27 far enough in the direction of the valve seat 30 that its valve lift corresponds to the stroke H m. The means of the piezoelectric actuator 23 applied force is then slightly lower than the sum of the forces by the biasing spring 37 and by the fuel on the valve closure member 27 be exercised. The ring disk 35 at which the valve closing member 27 is applied, is in this position by means of the biasing spring 37 against the attack 36 pressed. The ring disk 35 , which is thus in a stable position, dampens vibrations of the valve closure member 27 in the middle position and thus pressure oscillations in the valve control chambers 13 and 14 , which in turn could be reflected in vibrations in the controlled by means of the nozzle needle injection quantity.

In the middle position of the valve closing member 27 will both the valve control room 13 as well as the valve control room 14 Relieves, so that the two respectively assigned nozzle needles 4 and 5 be moved in the open position.

In 2 is an alternative embodiment of an injection valve 50 shown, the structure of which largely the same as that of the injection valve 1 equivalent. The injection valve 50 differ from the injector after 1 however, by the design of the valve control module 11 , in that it is a biasing spring 37 for a Zwischenhubanschlag 35 and a return spring 38 for a valve closure member 27 which are arranged coaxially, wherein the biasing spring 37 the return spring 38 embraces. The return spring 38 for the valve closure member 27 also supports on the valve body and acts on a bearing disc 51 that the shaft area 32 the valve closure member 27 embraces and at the head area 29 the valve closure member 27 is applied. The bearing disc 51 has an outer diameter which is larger than the inner diameter of the Zwischenhubanschlag forming annular disc 35 , The biasing spring 37 for the intermediate stroke stop 35 has a spring constant that is independent of the spring rate of the return spring 38 ,

The function of the intermediate stroke stop 35 of the injection valve 50 corresponds to that of Zwischenhubanschlags the embodiment according to 1 ,

Claims (5)

Valve for controlling fluids with a valve body in which a particularly piezoelectric actuator unit ( 23 ) for actuating a valve member guided in the valve body ( 24 ) is arranged, the at least one in a valve chamber ( 22 ) arranged valve closure member ( 27 ), which is provided with a first valve seat ( 30 ) and a second valve seat ( 33 ), wherein the valve closing member ( 27 ) in a first end position on the first valve seat ( 30 ) and in a second end position on the second valve seat ( 33 ) is applied, characterized in that a Zwischenhubanschlag ( 35 ) is provided, which has a center position of the valve closure member ( 27 ) and on the valve closure member ( 27 ) attacks. Valve according to claim 1, characterized in that the Zwischenhubanschlag ( 35 ) slidably mounted and by means of a spring ( 37 ) is biased. Valve according to claim 2, characterized in that the spring ( 37 ) is provided with a spring constant which is greater than a spring constant of a return spring ( 38 ) for the valve closure member ( 27 ) located at the Zwischenhubanschlag ( 35 ) is supported. Valve according to one of claims 1 to 3, characterized in that the Zwischenhubanschlag ( 35 ) with a paragraph serving as a stop ( 36 ) of the valve body cooperates. Valve according to one of claims 1 to 4, characterized in that the valve space ( 22 ) with at least two control rooms ( 13 . 14 ) for each one nozzle needle ( 4 . 5 ) of a fuel injection valve ( 1 . 50 ) connected is.