DE102006050042A1 - Injector, particularly common rail injector, for fuel injection in combustion chambers of internal-combustion engines, has actuator arranged in injector body, which is arranged to operate valve case of control valve - Google Patents

Abstract

The injector has an actuator (23) arranged in an injector body (2), which is arranged to operate a valve case of a control valve (24) relative to a valve seat surface in an axial direction. A nozzle needle (8) is adjusted depending on the pressure in a control chamber (15) between an open releasing position and a closing position of the fuel flow. The valve seat surface is arranged with fuel passage channel on the the seat element (35), which slides relative to the valve case.

Description

State of the art

The The invention relates to an injector according to the preamble of the claim 1.

The EP 1 612 403 A1 describes a rail-rail injector with a pressure-balanced in the axial direction control valve for locking and opening a fuel drain path from a control chamber. By means of the control valve, the fuel pressure can be influenced within the control chamber. The control chamber is supplied via a pressure channel with fuel from a high-pressure fuel storage. By varying the fuel pressure within the control chamber, a nozzle needle is moved between an open position and a closed position, wherein the nozzle needle in its open position releases the fuel flow into the combustion chamber of an internal combustion engine. The control valve has an adjustable in the axial direction by means of an electromagnetic actuator valve sleeve, which cooperates sealingly with a stationary conical valve seat surface. The valve seat surface of the control valve is formed on a component (throttle plate) defined within the injector body, through which the fuel discharge path for fuel is led out of the control chamber.

adversely in the known injector is that the guide clearance of the valve sleeve relative be chosen large must, to any offset between valve seat and valve sleeve and compensate for any run-out errors of the conical valve seat surface and thus to ensure the tightness of the control valve. Since the guide the valve sleeve the task, the fuel pressure from fuel drainage seal, has an increased leadership game also increased Leakage losses result. With increasing leakage losses increases however the needed output compressed fuel, resulting in a correspondingly larger, cost and energy intensive high pressure pump is needed.

Disclosure of the invention

Technical task

Of the The invention is therefore based on the object of proposing an injector, in which the leakage losses of the control valve are low.

Technical solution

These The object is achieved with the features of claim 1. advantageous Further developments of the invention are specified in the subclaims.

Of the Invention is based on the idea, the valve seat surface to arrange a seat member which is displaceable relative to the valve sleeve is. In this way, a mobile seat element or a mobile Valve seat get that going on during the assembly or during the operation by the action of the valve sleeve preferably au tomatically to the correct position moves relative to the valve sleeve, leaving the valve sleeve in closing position of the control valve sealingly rest on the valve seat surface of the element can. Because the leadership game the valve sleeve this If the offset no longer has to compensate, the guidance can be designed accordingly narrow which minimizes leakage losses. In the seat element a fuel passage is introduced, which is part of the fuel drain path out of the control chamber is. Through the fuel passageway can pump fuel from the control chamber into the valve sleeve arrive and lifted from the valve seat surface valve sleeve in the radial direction flow out. The control valve used is preferred around a pressure-balanced valve in the axial direction, which means with the control valve closed, the fuel from the fuel drain path in the axial direction no or only minimal pressure forces the valve sleeve exercised be, whereby only low contact forces in the closed state to guarantee the tightness needed become. An axial-pressure compensated control valve can be simple Way be realized by the fact that the sleeve bore has the same diameter like the valve seat. In other words, the valve sleeve is preferred with its inner diameter sealingly against the valve seat surface.

In Development of the invention is provided with advantage that the Seat element displaceable in a plane transverse to the adjustment of the valve sleeve is. This makes it possible the preferably arranged below the seat member throttle plate with Fuel drain path on both sides to train what to do the production considerably simplified. In the simplest case can the throttle plate are designed as a cylinder disc with throttle bore. The two parallel surfaces the throttle plate can be easily produced by double-plan loops.

According to an advantageous embodiment of the invention it is provided that the valve seat surface describes a spherical surface. It is not necessary to form the entire seat element spherical or partial spherical. A partial spherical formation in the region of the valve seat surface is sufficient. Due to the spherical valve seat surface angle errors are compensated in a simple manner, whereby an even longer and thus more accurate, less play axial axial guidance of the valve sleeve can be realized with low radial clearance, whereby Le losses are additionally reduced considerably. As a result, advantageously small-sized high-pressure pumps can be used. By combining the part-spherical design of the valve seat surface with a, in particular in a transverse plane to the adjustment axis displaceable seat member, a three-dimensional tolerance adjustment between the valve sleeve and the valve seat surface can take place.

Around to avoid that the seat element from the engagement area of the valve sleeve can slide out, is provided with advantage that the seat element also still open Control valve protrudes in the axial direction in the valve sleeve. Thus, a Movement of the seat element limited transversely to the direction of movement of the valve sleeve.

As already mentioned, It is advantageous, the seat element displaceable on a throttle plate to arrange. This forms a sliding surface for the seat element. The throttle plate may be that the valve seat surface is no longer incorporated into this must, on both sides plan and thus cost, for example as a cylinder plate.

at closed control valve is the seat element, in particular of a compression spring, preferably on the adjacent support member, in particular, the throttle plate, pressed, so that the tightness ensured between the seat element and the adjacent support member is. While the control valve opened is a dynamic pressure acts on the annular surface of the seat element. This Back pressure generated in the open Valve state a contact force on the mobile seat element, the prevents its lifting from the adjacent support member. To ensure, that the fuel flow when open Control valve, the seat element not from the adjacent support member lifts off, is in an embodiment of the invention, the diameter of the fuel passage channel within the seat element greater than the diameter of the fuel drain path in the adjacent support member.

Around to avoid high pressure fuel from the Control chamber or the fuel drain path between the support member, in particular the throttle plate, and the mobile seat moves and so on mobile seat element in the axial direction of the support member stands out, in the embodiment of the invention with the under high pressure Stagnant fuel surface to be underdeveloped maximum of the Seat element maximally sized, that just no axial force component in the opening direction, d. H. from the support member away on, the seat element acts. In other words, the maximum is in axial Direction with fuel pressure from the control chamber or the fuel outlet paths unterwan derbare area the seat element is smaller than that in the direction of the adjacent support member with fuel from a fuel chamber surrounding the seat element applied area of the Seat element.

This can for example be realized by the fact that on the Valve seat opposite bottom of the seat element a the fuel passage channel enclosing with radial distance Recess, in particular groove, is provided. The recess is preferably hydraulically connected to the fuel chamber surrounding the seat element, so that it is ensured that even with complete pressure infiltration the seat member from the inner diameter of the fuel passage channel to the inner diameter of the (relief) recess a resulting Axialkraft remains that the seat element on the adjacent support member, especially the throttle plate, presses.

to Design of the control valve as pressure-balanced in the axial direction Valve it is advantageous if the valve sleeve in the axial direction of a Bolt is interspersed, whose lateral surface also serve as a guide surface for the valve sleeve can. Characterized in that the bolt is supported on the injector body or in one piece with this is designed, can in the axial direction acting on him from the fuel drainage path Pressure forces on the injector body be given further. According to one manufacturing technology particularly advantageous variant, is the bolt not fixed to the injector body connected, but slidably disposed within the valve sleeve. The bolt is only by the axial pressure acting on it raised by the seat member and pressed in the direction of the jektor body. The Length of the Bolzens is dimensioned so that at its the seat element facing Front side of a sleeve chamber remains.

Brief description of the figures

Further Advantages, features and details of the invention will become apparent the following description of preferred embodiments and by reference the drawing; this shows in:

1 A first exemplary embodiment of an injector with a mobile seat element and lateral high-pressure supply,

2 : a detail from 1 which serves a pressure channel within a throttle plate for supplying a control chamber with fuel under high pressure,

3 : an enlarged partial view of 1 showing the arrangement of the mobile seat element on the throttle plate,

4 a further embodiment of an injector, wherein the control chamber is formed within a sleeve partially enclosing the nozzle needle,

5 a further embodiment of an injector, which is only partially shown and

6 : A perspective view of a possible embodiment of the mobile seat element.

Embodiments of the invention

In The figures are the same components and components with the same functions marked with the same reference numerals.

In 1 is an injector 1 shown. The injector 1 has an injector body 2 , a nozzle body 3 and one between injector body 2 and nozzle body 3 recorded cylindrical throttle plate 4 on. A nozzle retaining nut 5 is with the injector body 2 screwed and braced so the nozzle body 3 and the throttle plate 4 against the injector body 2 ,

The nozzle retaining nut 5 Coaxially surrounds the throttle plate 4 as well as partially the injector body 2 and the nozzle body 3 , The nozzle body 3 passes through a through hole in the axial direction 6 the nozzle retaining nut 5 ,

Inside the nozzle body 3 is a guide hole 7 formed, in which an elongated nozzle needle 8th is guided axially movable. At a needlepoint 9 has the nozzle needle 8th a closing area 10 on, with which they are in close contact with an inside of the nozzle body 3 trained needle seat 11 can be brought.

If the nozzle needle 8th at the needle seat 11 is applied, that is, is in a closed position, the fuel outlet from a nozzle hole arrangement 12 blocked. Is she on the other hand from the needle seat 11 lifted, fuel from a rule between the nozzle needle 8th and the circumferential shell of the guide bore 7 trained annulus 13 to the needle seat 11 over to the nozzle hole arrangement 12 flow and there are essentially injected under the high pressure (rail pressure) standing in a combustion chamber.

The nozzle needle 8th is by a biasing spring 14 biased toward its closed position.

The biasing spring 14 is inside a control chamber 15 arranged and supports at one end on an upper end face 16 the nozzle needle 8th and at the other end on the throttle plate 4 from.

How out 2 it can be seen, the control chamber 15 via a pressure channel 17 inside the throttle plate 4 with high pressure fuel from one through the injector body 2 guided fuel supply line 18 provided. The fuel supply line 18 is in hydraulic communication with a high pressure fuel accumulator, not shown, and continues through the throttle plate 4 and the nozzle body 3 into a high pressure annulus 19 inside the nozzle body 3 from where fuel over the annulus 13 to the nozzle hole arrangement 12 can flow.

Within the pressure channel 17 with which the control chamber 15 is supplied with fuel is an inlet throttle 20 arranged. About one with a drain throttle 21 equipped drainage path 22 (Drain hole in throttle plate 4 ) can remove fuel from the control chamber 15 drain to a discharge room.

By means of an electromagnetic actuator 23 can be a pressure balanced in the axial direction control valve 24 lock the fuel flow to the discharge room.

By the preload spring 14 and the action of the in the control chamber 15 prevailing pressure on the face 16 is an axially directed toward the combustion chamber closing force on the nozzle needle 8th exercised. This closing force acts axially against an opening force due to the action of the in the high-pressure annulus 19 prevailing pressure on one at the nozzle needle 8th trained step surface 25 is exerted on the nozzle needle. Is the control valve 24 in a closed position and is the fuel drain through the drainage path 22 locked, the closing force is greater than the opening force in the stationary state, which is why the nozzle needle 8th then assumes its closed position. Will the control valve 24 then opened, fuel flows out of the control chamber 15 from.

The flow cross sections of the inlet throttle 20 and the outlet throttle 21 are coordinated so that the inflow through the pressure channel 17 weaker than the drain through the drainage path 22 is and therefore with the control valve open 24 a net outflow of fuel results. The consequent pressure drop in the control chamber 15 causes the amount of closing force below the amount of opening force decreases and the nozzle needle 8th from the needle seat 11 takes off.

As in particular from 3 it can be seen has the control valve 24 an axially displaceable valve sleeve 26 on, stuck with an anchor plate 27 connected or integrally formed therewith. The anchor plate 27 acts with an electromagnet 28 of the electromagnetic actuator 23 together, the electromagnet 28 in a hole 29 of the injector body 2 is included. Of course, instead of an electromagnetic actuator, a piezoelectric actuator may also be used. About a spring 30 that attach to an annular shoulder 31 within the injector body 2 supports, becomes the electromagnet 28 against an upper end ring surface of a Ankerhubeinstellringes 32 pressed, which in turn with the opposite end ring surface on a sliding surface 33 the throttle plate 4 supported. Coaxial inside the armature stroke adjusting ring 32 is the anchor plate 27 taken and is thereby guided in the axial direction. By means of a coil spring 34 becomes the valve sleeve 26 in the closing direction, ie in the direction of a mobile seat element 35 with a part-spherical valve seat surface 36 spring force. The coil spring 34 relies on the upper ring edge of the valve sleeve in the plane of the drawing 26 as well as a dial 37 on an annular shoulder 38 of the injector body 2 from.

The seat element 35 is on the sliding surface 33 the throttle plate 4 movable (movable). The valve sleeve 26 is in 3 shown in the closed position and is sealing with its inner peripheral edge 39 on the annular valve seat surface 36 at.

Inside the valve seat 36 is a fuel passage 40 provided with the fuel drainage path 22 inside the throttle plate 4 Aligns and even part of this fuel drainage path 22 is. The inside diameter of the fuel passageway 40 is greater than the inner diameter of the fuel drain path 22 inside the throttle plate 4 so that the seat element 35 not from the fuel flow in the drawing plane above, can lift off. It can be seen that the seat element 35 in the axial direction in the valve sleeve 26 protrudes.

Inside the valve sleeve 26 is a cylindrical bolt 41 taken up, which in a short bore 42 of the injector body 2 is held. The lower end face 43 of the bolt 41 is at an axial distance from the mouth of the fuel passageway 40 arranged so that a fuel-filled sleeve space 44 inside the valve sleeve 26 remains free. From the fuel inside the sleeve space 44 act on the valve sleeve 26 only compressive forces in the radial direction. The compressive forces in the axial direction are over the bolt 41 who has the sleeve space 44 seals upwards in the plane of the drawing, on the injector body 2 supported.

In the embodiment shown, which is fixed to the valve sleeve 26 connected anchor plate 27 , as mentioned above the Ankerhubeinstellring 32 guided. On the other hand, the bolt 41 in the hole 42 taken, with the bolt 41 in turn, a guide for him enclosing valve sleeve 26 represents. Due to the relatively large distance of the guides is the angular error of the anchor plate 27 to the electromagnet 28 low. The electromagnet 28 is doing over the Ankerhubeinstellring 32 parallel to the throttle plate 4 aligned.

Alternatively, the valve sleeve 26 over its outer diameter in an inner bore 45 of the electromagnet 28 be guided, as in the embodiment according to 5 is realized. In this case, eliminates the leadership of the bolt 41 in the injector body 2 as well as the guide between the anchor plate 27 and the anchor plate adjusting ring 32 ,

As continues in 5 it can be seen is the bolt 41 contrary to the embodiment according to 1 longitudinally displaceable within the valve sleeve 26 is absorbed by the fuel pressure within the sleeve space 44 in the axial direction against the injector body 2 pressed.

The seat element 35 is in the embodiment according to 5 also transverse to the adjustment of the valve sleeve 26 on the sliding surface 33 the throttle plate 4 slidably, causing a misalignment of the throttle plate 4 or the seat element 35 to the injector body 2 or to the valve sleeve 26 , which can occur during assembly, by the mobile seat element 35 balanced. About the effect of the coil spring 34 becomes the mobile seat element 35 still during assembly and / or during operation to the correct, ie in the axial direction with the valve sleeve 26 aligned position, shifted.

In 4 a further embodiment of an injector is shown, wherein the control room 15 unlike that in 1 illustrated embodiment within a sleeve 46 is formed, which the nozzle needle 8th Coaxially encloses. The pressure channel 17 to supply the control chamber 15 with high-pressure fuel is as an annular channel radially between the nozzle needle 8th and the sleeve 46 educated.

In 6 is a possible embodiment of a seat element 35 shown. The seat element 35 is formed substantially circular cylindrical. While the control valve 24 is open, a dynamic pressure acts from a seat element 35 surrounding, in 3 shown, fuel chamber 47 on the in the plane of the drawing 4 upper annular surface of the mobile seat element 35 , This dynamic pressure generated in the open state of the control valve 35 a contact pressure on the mobile seat element 35 , the a lift off the throttle plate 4 prevented. As already mentioned, the cross-sectional area of the centric fuel passage is 40 inside the seat element 35 larger than the cross-sectional area of the drainage path 22 inside the throttle plate 4 so that the flow is the seat element 35 does not lift off to the top. To avoid high-pressure fuel between the throttle plate 4 and the mobile seat element 35 migrates, this stands out, is at a radial distance to the fuel passage channel 40 a relief groove 48 with an inner diameter D in the bottom 49 of the seat element 35 brought in. The inner diameter D of the relief groove is smaller than the outer diameter of the seat element 35 at the bottom of it 49 opposite top. This ensures that even with complete pressure infiltration of the seat element 35 from the inside diameter of the fuel passageway 40 to the inner diameter of the relief groove 48 a resulting axial force remains, which is the seat element 35 on the throttle plate 4 suppressed. The relief groove 48 is with an in 6 as a spiral groove 50 formed recess with the outer diameter of the seat element 35 and thus with the in 3 shown fuel chamber 47 Connected to allow the built up fuel pressure in the low pressure area within the fuel chamber 47 can drain away.

Claims (10)

Injector for injecting fuel into combustion chambers of internal combustion engines, in particular common-rail injector, with one in an injector body ( 2 ) arranged actuator ( 23 ), which has a valve sleeve ( 26 ) of a control valve ( 24 ) relative to a valve seat surface ( 36 ) is arranged in the axial direction, wherein by means of the control valve ( 24 ) a fuel drain path ( 22 ) from a control chamber ( 15 ), which with a fuel supply pressure channel ( 17 ) is in hydraulic communication, lockable and is releasable, which in turn the pressure in the control chamber ( 15 ) is influenced, wherein a nozzle needle ( 8th ) in dependence on the pressure in the control chamber ( 15 ) between a fuel flow releasing opening position and a closed position is adjustable, characterized in that the valve seat surface ( 36 ) on a relative to the valve sleeve ( 26 ) displaceably arranged seat element ( 35 ) with fuel passage channel ( 40 ) is arranged. Injector according to claim 1, characterized in that the seat element ( 35 ) in a plane transverse to the adjustment of the valve sleeve ( 26 ) is displaceable. Injector according to one of the preceding claims, characterized in that the valve seat surface ( 36 ) is partially spherical curved. Injector according to one of the preceding claims, characterized in that the seat element ( 35 ) in an open position of the valve sleeve ( 26 ) in the axial direction in the valve sleeve ( 26 ) protrudes. Injector according to one of the preceding claims, characterized in that the seat element ( 35 ) slidably on a the control chamber ( 15 ) limiting throttle plate ( 4 ) is arranged through which the fuel drain path ( 22 ), at least in sections, passes through. Injector according to one of the preceding claims, characterized in that the maximum in the axial direction with fuel pressure from the control chamber ( 15 ) Submersible surface of the seat element ( 35 ) is smaller than that in the opposite direction with fuel pressure from a seat element ( 35 ) surrounding fuel chamber ( 47 ) acted upon surface of the seat element ( 35 ). Injector according to claim 6, characterized in that on the valve seat surface ( 36 ) facing away from the bottom ( 49 ) of the seat element ( 35 ) at a radial distance to the fuel passage channel ( 40 ) a bearing surface of the seat element enclosing recess ( 48 ), in particular groove, is introduced. Injector according to claim 7, characterized in that the recess ( 48 ) hydraulically with the seat element ( 35 ) surrounding fuel chamber ( 47 ) connected is. Injector according to one of claims 5 to 8, characterized in that the cross-sectional area of the fuel passage channel ( 40 ) in the seat element ( 35 ) is greater than the cross-sectional area of the fuel drain path (FIG. 22 ) in the throttle plate ( 4 ). Injector according to one of the preceding claims, characterized in that the valve sleeve ( 26 ) of a one-piece with the injector body ( 2 ) formed or supported on this, preferably axially displaceable bolt ( 41 ) is interspersed.