DE10065221B4 - Directly controlled 2-seat valve for fuel injection systems - Google Patents

Abstract

Facility for injecting fuel into the combustion chambers of an internal combustion engine with a control valve, which has a housing in a housing (1) movable valve piston (6), that of a housing-side Valve chamber (19) is enclosed, in a housing-side inlet (20) of a High-pressure collecting room opens, and the valve piston (6) by means of an actuator (3) in a housing bore (2) operable is, creating a nozzle inlet (18) to an injection nozzle capping or is releasable, wherein on the valve piston (6) two interlinked 2/2-way valves (37, 38) are formed and the valve piston (6) of a valve body (13) is traversed, wherein a first 2/2-way valve (38) on the outside the valve piston (6) in the region of the housing-side valve chamber (19) is arranged, the valve piston (6) has a second internal 2/2 way valve (37) contains its a seat (10) formed on an extension of the valve body (13, 13 ') is and the other seat (11) of the second, internal 2/2-way valve (37) on one inner valve space (9) of the valve piston (6) is executed, characterized in that ...

Description

technical area

at Fuel injection systems for directly injecting internal combustion engines come control valves, such as. 3/2-Steuerventile used to the nozzle inlet to the injector with the inlet from the high pressure common rail. For 3/2 control valves, which are designed as seat slide valves, can be used in small Strokes large Absteuermengen occur in the leak, which affect the efficiency of such seat slide valves.

State of technology

DE 43 41 546 A1 relates to a fuel injection device for internal combustion engines. This includes a high-pressure fuel pump, which promotes fuel from a low-pressure chamber in a high-pressure accumulator. The high pressure accumulator is connected via high pressure lines with projecting into the combustion chamber of the engine to be supplied injectors. Their opening and closing movement is controlled in each case by an electrically controlled, arranged in the high-pressure line at the injection valve control part. The control valve has a piston-shaped valve member with two mutually facing, with two valve seats cooperating valve sealing surfaces, of which a first valve sealing surface opens the connection of the high-pressure line to the injection valve and a second valve sealing surface the connection of the injection valve with a discharge space. The second valve sealing surface is preceded by a Rücksaugbund the valve member, the release of the second valve sealing surface of its seat at the end of the injection, a Rücksaugvolumen in which relaxes a portion of the front of the injection valve fuel quantity.

JP 06 066 222 A1 relates to a fuel injector. Between an end face, in which a high-pressure bore opens, which extends in a holding body, and an end face of a body, in which a further part of a high-pressure bore is formed, an insert is arranged. The insert is configured annular and embedded by means of a press fit in the end face of the holding body. When pressure is applied to the high-pressure bore sections, the annular-shaped insert deforms in the radial direction, so that it acts as a sealing element between the sections of the high-pressure bore in the bodies.

EP 0 999 360 A1 refers to a control valve for a Fluiddosiervorrichtung. In a housing there is a valve body, in which an openable with fluid pressure inlet, a drain and a housing bore open. In the housing bore a sealing element is arranged axially displaceable and leaking. This sealing element can be pressed to achieve a seal on a valve seat of the process. A valve tappet is guided in the drain permeable and allows a displacement of the sealing element according to its stroke.

DE 196 05 277 A1 relates to a solenoid-operated hydraulic control valve for use in the fuel injection system of an internal combustion engine. The control valve includes a valve piston which is attracted by an electromagnet when the solenoid is turned on. This selectively enables or disrupts fluid communication between an inlet and an outlet. There is provided a fluid chamber to which a fluid pressure is supplied from the inlet side. The fluid pressure in the fluid chamber acts on the valve piston in a direction opposite to the force of attraction of the solenoid when it is turned on. Thus, the attraction force generated by the residual magnetism of the electromagnet is compensated immediately after the electromagnet is turned off.

DE 197 09 794 A1 refers to a valve for controlling fluids. A valve member has an actuating piston, which is acted upon by a spring in the closing direction of the valve member for resting on a valve seat. The actuating piston defines a pressure chamber, which is further limited by a piezoelectric actuator, by the movement of which a pressure increase in the pressure chamber can be generated, by which the actuating piston against the force of the spring in the opening direction is adjustable. The actuator is arranged parallel to the actuating piston and lying next to it, wherein the pressure chamber is divided into a first subspace and a second subspace and the subspaces are connected to each other via a transverse to the axis of the actuating piston channel.

at Control valves with small strokes can disproportionately high during operation Absteuermengen in the leak oil drain arrive, which adversely affects the efficiency of such valves.

Advantage of invention

The inventively proposed solution to form two 2/2-way valves on the valve piston of a control valve, simplifies the construction of a control valve considerably. It can be the disadvantages of consisting of a plurality of valve bodies control valves, where two seats are formed on two different bodies and production-related tolerances and positional errors occur, which significantly affect the operation exclude SEN. The guiding of a valve piston on the valve body on the inside and in a housing bore on the outside allows a compact construction and centering of the control valve designed according to the invention. Since the seat diameter on the outer circumference of the valve piston corresponds to the guide diameter of the valve piston in the housing, the control valve according to the invention is force-balanced. This opens up the possibility of directly controlling the control valve by means of a piezoelectric actuator so that short positioning times can be achieved without the interposition of further elements transmitting the actuating forces.

alternative may be between the actuator actuating the valve piston - e.g. designed as a piezo plate - and the opposite end face of the valve piston, a hydraulic interrupter interposed be that for an increase the transferable restoring forces Caring.

through the actor lets himself go according to the present Invention of the valve piston of the control valve translational in casing move so that the nozzle inlet to a nozzle needle surrounding nozzle space, with housing side Inlet can be connected to or from the high-pressure common rail this is separable. This can be the nozzle needle both by the pressure build-up in the nozzle chamber, at the there at the nozzle needle aufsteuern trained pressure level, as well as by means of a separate open direct nozzle control or open shut down. A direct nozzle needle control becomes used in particular when short successive injection phases, e.g. Pre-injection phase, main injection phase and Nacheinspritzphase during a Injection process to be realized and it is a fast Control for opening or close the nozzle needle requirement. The valve piston is in a centering surrounding its outer peripheral surface guided. The centering also takes place through adjacent housing bore walls in case that too little space available stands, the use of a serving as a centering guide body in casing of the invention configured Control valve does not allow.

With the control valve according to the invention can be in the drain drain low Absteuermengen keep low, which the efficiency of a such control valve significantly improved. Next to it is the valve piston, on the two seats are designed to produce tolerances more accurate compared to a Solution, at the two seats are to be formed on two different components.

drawing

Based In the drawings, the invention will be described in more detail below.

The single figure shows a longitudinal section through an inventively obtained Control valve on which two 2/2-way valves are formed.

variants

Of the Figure is a longitudinal section by an inventively procured Control valve removable.

A housing 1 a control valve for closing or releasing a nozzle inlet 18 to an injection nozzle of a direct injection internal combustion engine comprises a housing bore 2 in which a valve piston 6 is movably received. The valve piston 6 protrudes with an operator-side face 7 in a pressure chamber of a hydraulic translator 4 , This is done by a translator piston 5 which in turn is acted upon by an actor 3 is pressed. The actor 3 may for example be designed as a pie zo-actuator, a solenoid valve or as a mechanical / hydraulic translator.

The actor 3 can also be directly on the front page 7 of the valve piston 6 act and the valve piston 6 in the enclosing housing bore 2 in vertical direction 34 move up and down.

The feller-side front page 7 of the valve piston 6 opposite is an annular shaped face 28 formed, on which a closing spring 26 is applied. This is supported by a surface 31 a leadership body 13 from. The closing spring 26 can also be directly on a wall of the valve piston 6 surrounding housing 1 issue.

The valve piston 6 is approximately centrally on its outside of a housing-side valve chamber 19 enclosed. In the housing-side valve chamber 19 opens an inflow 20 from the high-pressure collecting space (Common Rail). The volume of fuel in the high-pressure accumulator is constantly under high pressure. The compressibility of the fuel achieved by the high pressure is utilized in order to permanently maintain a storage effect. If fuel for an injection at an injector of a direct-injection internal combustion engine from the high-pressure accumulator (common rail) taken, the pressure in the high-pressure accumulator remains almost constant. Likewise, pressure fluctuations are attenuated by the pulsating Versorgungsorgnug by the high-pressure accumulator acting on the high-pressure pump, ie balanced.

Furthermore, in the housing 1 of the control valve according to 1 a nozzle inlet 18 recorded, which at a nozzle inlet orifice 17 into the housing bore 2 , which the valve piston 6 absorbs, flows. The estuary 17 of the nozzle inlet 18 lies opposite a constriction site 16 on the outside of the valve piston 6 , At the valve piston 6 approximately centrally enclosing housing-side valve chamber 19 is a housing-side seat 21 formed, on which a seat 22 on the peripheral surface of the valve piston 6 is applied. The diameter of the seat 22 is identical to the diameter 23 of the valve piston 6 in the housing bore 2 of the housing 1 so that the valve piston 6 is balanced and by means of a piezo plate 3 directly or indirectly in direction 34 inside the housing bore 2 of the housing 1 can be adjusted.

The mouth 17 of the nozzle inlet 18 is assigned to the outer surface of the housing bore 2 in vertical direction 34 up and down movable valve piston 6 a flattening 15 educated. This is in turn with a valve piston 6 transversely to the axis of symmetry passing through transverse bore 14 , in turn, in a longitudinal bore 8th in the valve piston 6 empties. The longitudinal bore 8th , which ends in a blind hole at the bottom of the valve piston, is in a first diameter 24 executed. She goes into an inner valve chamber 9 over, inside the valve piston 6 is trained. In the valve room 9 of the valve piston 6 protrudes an extension of a guide body 13 , The guide body 13 is provided with a spike-shaped extension, on whose sides flow surfaces 12 are formed, via which fuel to the leakage oil side 30 . 32 of the control valve according to 1 can flow.

At the end of the mandrel-shaped extension of the guide body 13 there is an inner seat 10 with a seat 11 working together on the inner valve chamber 9 inside the valve piston 6 is trained. This will be within the valve piston 6 an inboard 2/2-way valve is formed while passing through the housing-side valve space below 19 trained valve seat, external 2/2-way valve 38 is pictured.

The thorn-shaped extension of the guide body 13 forms an inner guide surface for the valve piston 6 in the housing bore 2 in vertical direction 34 is movable. On the outside is the valve piston 6 , executed in diameter 23 , from the housing bore 2 enclosed and guided by them. The length of the flow surfaces 12 on the thorn-shaped extension of the guide body 13 are dimensioned so that with open, internal 2/2-way valve 37 Fuel from the inner valve chamber 9 along the flow surfaces into a free space 35 can flow in. In this free space, is the already mentioned closing spring 26 let in, on the one hand at the annular end face 28 of the valve piston 6 supported and on the other hand on a contact surface 31 of the leadership body 13 is applied.

At the flow surfaces 12 the thorn-shaped extension of the guide body 13 along flowing fuel enters the free space 35 and flows from there via a on the guide body 13 Trained transverse bore 30 in the direction of the leak oil drain 32 ,

In the illustrated embodiment, the guide body 13 with one the free space 35 in which the closing spring 26 is added, surrounding cup-shaped approach provided. At this is a centering 27 formed, which is a part of the valve piston 6 encloses on its outer surface and in the housing 1 centered on the control valve. Further, the cup-shaped, the upper portion of the valve piston 6 enclosing part of the guide body 13 groove 36 intended. With the embodiment of an area of the valve piston 6 at the top enclosing guide body 13 becomes a centering of the valve piston 6 in the upper part of the housing 1 created.

On the guide body 13 ' is the contact surface 31 for the closing spring 26 formed, the lateral guidance of the closing spring 26 is taken over by housing-side surfaces.

According to the embodiment in 1 is the guide body 13 with centering 13 ' in a housing-side cavity 33 housed and with a gap to the wall of the housing 1 added. In this gap between cup-shaped approach of the guide body 13 and the side wall of the housing 1 the leakage oil side comes out of the free space 35 escaping fuel through the transverse bore 30 in the leak oil drain 32 and flows back from these in a fuel reservoir.

In the area in which the valve piston 6 on the thorn-shaped extension of the guide body 13 respectively. 13 ' is guided, the thorn-shaped extension is in a second diameter 25 executed, which is larger than the first diameter 24 the bore 8th in the lower area of the valve piston 6 , which with the transverse bore 14 in the valve piston 6 communicates.

The operation of the control valve according to the invention can be represented as follows:
Through between the annular end face 28 and the contact surface 31 on the guide body 13 bwz. 13 ' absorbed closing spring 26 is the valve piston 6 always with its outer seat diameter 22 in the housing-side seat 21 at the lower end of the housing side provided valve space 19 posed. This is the feed 20 from the high pressure accumulator and the nozzle inlet 17 . 18 separated to the injection nozzle of a direct-injection internal combustion engine. Is the example, designed as a piezoelectric actuator Steller 3 and thus the translator on the piston 5 a hydraulic translator 4 actuated, a pressure on the end face acts 7 and the valve piston 6 moves inside the housing bore 2 against the action of the closing spring 26 upwards. As a result, high-pressure fuel flows through the inlet 20 from the high-pressure common rail into the housing-side valve space 19 and over the open seats 21 respectively. 22 along a constriction site 16 on the outside of the valve piston 16 through the mouth 17 the nozzle inlet in just this and from there into a nozzle chamber of an injection nozzle. In the nozzle chamber, which surrounds a nozzle needle of an injector, a pressure stage may be provided, which causes an upward control of the nozzle needle when pressure is applied to the nozzle chamber; In addition, a direct control of the nozzle needle to release or to close the injector may be provided to short injection intervals, ie to realize short successive injection phases.

After injection into the combustion chamber of an internal combustion engine, a closing movement of the valve piston takes place 6 by switching off the actuator 3 so that the valve piston 6 , acted upon by the closing spring 26 on an annular contact surface 28 , in its outer, housing-side seat 21 retracts. This is the first, on the outside of the valve piston 6 provided 2/2-way valve 38 closed.

Moves the valve piston 6 , acted upon by the closing spring 26 in his housing-side seat 21 one, be the feed 20 from the high pressure accumulator and the nozzle inlet 18 separated from each other. The nozzle inlet 18 is now relieved that of the constriction 16 from fuel via one on the outside of the valve piston 6 provided flattening in a transverse bore 14 on the valve piston 6 flows in and from this via a bore 8th in an internal valve chamber 9 entry. By the vertical downward closing movement of the valve piston 6 are the inner seat 10 attached to the thorn-shaped extension of the guide body 13 is formed and the seat 11 at the valve room 9 moved apart, so that the internal 2/2-way valve 37 is open and fuel over the outflow areas 12 in the open space 35 and from there over a cross hole 30 in the leak oil drain 32 can flow out.

Accordingly, during the closing movement of the valve piston 6 , ie the movement of the valve piston 6 with its seat diameter 22 in the housing side provided seat 21 the inlet 20 from the high pressure accumulator and the nozzle inlet 18 separated, while at the same time a discharge of the nozzle inlet 18 over the drilling system 15 . 14 . 8th and the open internal 2/2-way valve 37 can be done from the leakage side. Conversely, when opening the valve piston 6 , ie a vertically upward movement of the valve piston 6 against the action of the closing spring 26 a retraction of the seat 11 on the inside valve space to the thorn-shaped extension of the guide body 13 trained inner seat 10 ensured so that during the connection of the inlet 20 from the high-pressure accumulation chamber via the valve chamber 19 and the opened first 2/2-way valve 38 the nozzle inlet 8th Leak oil side is closed.

This design possibility of a valve piston has manufacturing technology seen significant advantages, since two seats can be formed on a body. Production-related position errors that can occur with control valves with two independently movable valve bodies are excluded by the inventive configuration of the control valve. Furthermore, the solution according to the invention opens up the possibility of an independent of the control of the valve piston 6 in the case 1 to provide usable control of the nozzle needle. By forming the valve body as a double-seat valve, ie the integration of two 2/2-way valves 37 . 38 a very simple structure of a control valve for fuel injection systems can be achieved.

1

casing

2

housing bore

3

actuator

4

Hydraulic translator

5

Booster piston

6

plunger

7

face

8th

drilling

9

inner valve chamber

10

Inner seat

11

Seat

12

Abströmungsfläche

13

guide body

13 '

Guide body without centering

14

cross hole

15

flattening

16

constriction

17

Nozzle inlet mouth

18

nozzle inlet

19

Mutual housing valve chamber

20

Intake High-pressure collecting space (Common Rail)

21

housing-side seat

22

Outer seat

23

Guide diameter

24

first diameter

25

second diameter

26

closing spring

27

Zentriernug

28

Ring-shaped end face

29

Guide sealing spring

30

cross hole guide body

31

Contact surface closing spring

32

Oil drain

33

housing cavity

34

Move plunger

35

free space

36

groove

38

first 2/2 way valve

37

second 2/2 way valve

Claims (6)

Device for injecting fuel into the combustion chambers of an internal combustion engine with a control valve, which is located in a housing ( 1 ) movable valve piston ( 6 ) formed by a housing-side valve space ( 19 ), in which a housing-side inlet ( 20 ) opens a high-pressure accumulation chamber, and the valve piston ( 6 ) by means of an actuator ( 3 ) in a housing bore ( 2 ), whereby a nozzle inlet ( 18 ) is closable or releasable to an injection nozzle, wherein on the valve piston ( 6 ) two interlinked 2/2-way valves ( 37 . 38 ) are formed and the valve piston ( 6 ) of a valve body ( 13 ), wherein a first 2/2-way valve ( 38 ) on the outside of the valve piston ( 6 ) in the region of the housing-side valve space ( 19 ) is arranged, the valve piston ( 6 ) a second internal 2/2-way valve ( 37 ), whose one seat ( 10 ) on an extension of the valve body ( 13 . 13 ' ) is formed and the other seat ( 11 ) of the second, internal 2/2-way valve ( 37 ) on an inner valve space ( 9 ) of the valve piston ( 6 ) is executed, characterized in that the valve piston ( 6 ) of the control valve on the valve body ( 13 . 13 ' ) inside and in a housing bore ( 2 ) of the housing ( 1 ) is guided on the outside, wherein the valve body ( 13 . 13 ' ) a the valve piston ( 6 ) surrounding centering ( 27 ) and located on a wall of a housing cavity ( 33 ) of the housing ( 1 ) is supported. Device according to claim 1, characterized in that the diameter of a seat ( 22 ) of the first 2/2-way valve ( 38 ) the guide diameter ( 23 ) of the valve piston ( 6 ) in the housing bore ( 2 ) corresponds. Device according to claim 1, characterized in that on the guide body ( 13 ) of the valve piston ( 6 ) Outflow surfaces ( 12 ) are formed via the fuel via a bore ( 30 ) into a drain ( 32 ). Device according to claim 3, characterized in that the second internal 2/2-way valve ( 37 ) at pressure relief of the nozzle inlet ( 18 ) over a flattening ( 19 ) and a bore system ( 8th . 14 ) in the valve piston ( 6 ) this to the drainage ( 32 ) aufsteuert. Device according to claim 1, characterized in that the second internal 2/2-way valve ( 37 ) when controlling the outer 2/2-way valve ( 38 ) the nozzle inlet ( 18 ) Leak oil side closes. Device according to claim 1, characterized in that the guide body ( 13 . 13 ' ) a closing spring ( 26 ) associated with one, an actuator-side end face ( 7 ) opposite, annular end face ( 28 ) of the valve piston ( 6 ) acts.