DE102007047129A1 - Injector with sleeve-shaped control valve element - Google Patents

Abstract

The invention relates to an injector (1) for injecting fuel into the combustion chamber of an internal combustion engine, in particular a common rail injector, with an injection valve element (10) which is dependent on the pressure in a control chamber (22) between a closed position and an open position axial direction is adjustable, wherein the control chamber (22) by means of an adjustable valve sleeve (28) having control valve (29) with an injector return port (7) is connectable, and wherein the valve sleeve (28) with an anchor plate (31) is operatively connected, the for adjusting the valve sleeve (28) with an electromagnetic actuator (31) cooperates. According to the invention, a channel (40) extending in the axial direction is arranged within the valve sleeve (28), through which fuel flows when the control valve (29) is open from the control chamber (22) on the anchor plate (31) to the injector return port (7). can flow.

Description

State of the art

The The invention relates to an injector for injecting fuel in a combustion chamber of an internal combustion engine, in particular a Common rail injector, according to the preamble of Claim 1.

From the EP 1 612 403 A1 is a common rail injector with a pressure balanced in the axial direction control valve known. By means of the control valve, which has a sleeve-shaped control valve element, the fuel pressure can be influenced within a control chamber bounded on the end side by an injection valve element. By varying the fuel pressure within the control chamber, the injection valve element is adjusted between an open position and a closed position, wherein the injection valve element releases the fuel flow into the combustion chamber of an internal combustion engine in its open position. The sleeve-shaped control valve element is connected to an anchor plate, which cooperates with an electromagnetic actuator for adjusting the sleeve-shaped control valve element. When the control valve is open, the fuel flows out of the control chamber through an armature space receiving the armature plate in the direction of an injector return port. In this case, the outflowing fuel impinges on the radial, lower, the control valve seat facing surfaces of the armature plate, whereby flow forces acting on the armature plate, which lead to an unwanted influence on the injection. These flow forces have a particularly strong effect in the known injector, since the control valve is designed as a valve pressure-balanced in the axial direction and only small magnetic forces are realized with the electromagnetic actuator, which in turn makes the armature plate comparatively easy by the flow forces occurring when the control valve is open can be adjusted.

Disclosure of the invention

Technical task

Of the The invention is therefore based on the object, an improved injector to propose, in which the of the with open control valve flowing in the direction of the injector return port Fuel caused, acting on the anchor plate and with it the switching behavior of the injector negatively influencing flow forces at least reduced.

Technical solution

These Task is with an injector with the features of the claim 1 solved. Advantageous developments of the invention are specified in the dependent claims. Fall within the scope of the invention also all combinations of at least two of in the description, the claims and / or the figures revealed Features.

Of the Invention is based on the idea that acting on the anchor plate Flow forces from with open control valve (Servo valve) in the direction of the injector return port thereby minimizing or preferably completely to avoid having the fuel, at least one partial fuel stream, with control valve open by a channel inside the valve sleeve in the axial direction in the direction of the injector return port flows. The fuel flows within the Valve sleeve, if necessary additionally within the anchor plate on the armature plate in the axial direction radially inward over, without that flow forces the switching behavior of the injector could affect the anchor plate Act. The out of the control chamber with open control valve outgoing fuel (tax amount) must be provided by the provision the channel within the valve sleeve is not through or along the large, the control valve seat facing (lower) Flow surfaces of the anchor plate in the axial direction, but flows centrally in the direction of the injector return. An invented according to the concept of the invention injector with a within the valve sleeve (control valve member) of the control valve arranged channel has an optimized switching behavior, since from the control chamber towards the injector return port caused flowing fuel in known injectors Valve sleeve vibrations are avoided. The optimized switching behavior is characterized in particular by minimized injection tolerances out. The valve sleeve of the control valve is at a formed according to the concept of the invention injector with the valve sleeve operatively connected, that is, either in one piece with this trained or, in particular form-fitting, with this connected.

In Development of the invention is provided with advantage that the Control valve, if this rests against its control valve seat, in axial direction is pressure balanced. This can preferably be realized thereby Be sure that the sealing edge (seat edge) on the inner circumference of the valve sleeve is arranged so that a pressure step on the valve sleeve, which cause an opening force on the valve sleeve would, is avoided.

In particular, the provision of a centric, extending within the valve sleeve in the axial direction channel for discharging at least a subset, preferably the total amount of fuel flowing when the control valve is open in the direction of the injector return port allows fuel the realization of a particularly preferred embodiment of the injector, wherein the injector return port for connecting the injector to a return line for a fuel control amount is arranged centrally on a side remote from the combustion chamber end face (cover) of the injector. Such an arrangement of the injector return port (low-pressure port) can be produced inexpensively and, above all, permits simple mounting of the injector ports on the internal combustion engine. Furthermore, asymmetrical deformations are avoided by the injector internal pressure due to a substantially coaxial injector configuration with an injector return port arranged centrally on one end side.

Prefers is an embodiment in which the channel is up to the remote from the control valve seat end of the valve sleeve enough, so the fuel from the front side of the valve sleeve or possibly the front side of the valve sleeve surrounding or axially adjacent to this arranged anchor plate flows out. It is conceivable according to a first alternative, that the channel in the anchor space (preferably above the anchor plate) opens out and from there further in the axial direction to Injector return flows. According to one second alternative, it is conceivable that the channel lengthened so is that this is not directly in the anchor space, but in one above the armature space in an electromagnet arrangement of the actuator arranged central channel opens.

From particular advantage is an embodiment of the injector, in which a pressure pin is arranged inside the valve sleeve that is, as a member having the control valve seat is formed separate component. This pressure pin is supported either at an injector component spaced from the control valve seat, preferably spring-assisted, from or is in one piece with an injector component spaced from the control valve seat educated. Such an embodiment has the advantage that the control valve seat is easily accessible during its manufacture is and the guide for the valve sleeve and the control valve seat on separate, to be processed separately Components are formed. The task of the separate pressure pin is to absorb the compressive forces acting in the axial direction, support and thereby the inner cross section of the valve sleeve high-pressure tight seal in the axial direction, so that when the control valve is closed, that is, when the valve sleeve is in contact with the control valve seat, no fuel from the control chamber to the injector return can flow. Of course, one is also Embodiment feasible, in which the pressure pin in one piece is formed with the Injektorbauteil, where also the control valve seat located.

From particular advantage is an embodiment in which the Channel formed within the valve sleeve as an annular channel is, the radially outside of the inner circumference of the valve sleeve and radially inward of, preferably centrally within, the valve sleeve arranged, pressure pin is limited.

to Realization of an axially extending within the valve sleeve Ring channel is an embodiment of advantage in which the pressure pin has a thickened (lower) end portion, as a high pressure seal for sealing the inner cross section of Valve sleeve in the axial direction (upwards) is used. By this thickened end section passes through the channel not, but begins in the axial direction only at one arranged adjacent to the thickened end portion, thin Section of the pressure pin, which preferably in the axial direction extends to a spaced from the control valve seat member and is supported on this in the axial direction or in one piece is formed with this. The diameter is preferably the thickened end portion at least approximately the inner diameter of the valve sleeve. The diluted one Section has a smaller diameter than the thickened End portion, which is dimensioned such that on the one hand with a channel sufficient cross-section to derive the fuel tax results and other strength problems are avoided. The pressure pin can be formed in one piece as well as in several parts become.

In Further development of the invention is advantageously provided that in the component on which the pressure pin is supported in the axial direction, at least one leading to injector return Axial channel is provided. Preferably, the component is, on which the pressure pin is supported, within one, in one Electromagnet assembly arranged, central channel, the immediate leads to the injector return.

There the fuel due to the sealing effect of the thickened end portion the pressure pin not immediately after he subordinate one of the control chamber Outflow throttle has flowed into the channel within the Valve sleeve can flow, is in accordance with a preferred embodiment provided that the control valve seat surrounded by an annulus into which the fuel with open control valve flowing from within the valve sleeve in the radial direction can, with this annular space hydraulically with the inside of the valve sleeve arranged channel is connected. Preferably, the hydraulic Connection between the annulus and inside the valve sleeve arranged channel as at least one bore, preferably as at least one radial bore, executed by the Annulus arranged in the inside of the valve sleeve Channel leads to the discharge of the fuel.

Especially preferred is an embodiment in which the annulus in the axial direction and possibly also in the radial direction of a Component is limited, as a guide member for leadership the valve sleeve formed on its outer circumference is. This guide member is preferable as one of the Control valve seat component having a separate component executed, so that the guide for the axially adjustable Valve sleeve and the control valve seat separately from each other can be produced and are easily accessible. For optimizing the flow behavior, in particular for Venting of the armature space, is an embodiment advantageous in ensuring a low Flow through the armature space fuel (partial flow of the Fuel control amount) via a throttle from the annulus in the anchor space and from there to the injector return can flow. Depending on the design of the injector can up Such a throttle are dispensed with, especially if the unavoidable leakage between the valve sleeve and the outer leadership is sufficiently large, to ensure a ventilation of the anchor space.

Brief description of the drawings

Further advantages, features and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. This shows in the only one 1 a trained as a common rail injector injector with a disposed within a valve sleeve of a control valve channel (annular channel).

embodiments the invention

In 1 is an injector designed as a common rail injector 1 for injecting fuel into a combustion chamber of an internal combustion engine of a motor vehicle. A high pressure pump 2 Promotes fuel from a reservoir 3 in a high-pressure fuel storage 4 (Rail). In this fuel, especially diesel or gasoline, under high pressure, of about 2000 bar in this embodiment, stored. To the high-pressure fuel storage 4 is the injector 1 in addition to other, not shown injectors via a supply line 5 connected. The supply line 5 flows into a pressure room 6 (High pressure area) of the injector 1 and flows from there during an injection process directly into the combustion chamber of the internal combustion engine. The injector 1 is via an injector return port 7 to a return line 8th to the reservoir 3 connected. About the return line 8th may be a later to be explained control amount of fuel from the injector 1 to the reservoir 3 drain and be fed from there from the high pressure circuit again.

Within an injector body 9 is a one-piece injection valve element in this embodiment 10 , which can also be made in several parts if necessary, adjustable in the axial direction. In this case, the injection valve element 10 within a nozzle body 11 guided on its outer circumference. This nozzle body 11 is by means of a union nut, not shown, with the injector body 9 braced.

The injection valve element 10 points at its peak 12 a closing area 13 on, with which the injection valve element 10 in a tight contact with one inside the nozzle body 11 trained injection valve element seat 14 can be brought.

When the injection valve element 10 at its injection valve element seat 14 is applied, that is, is in a closed position, the fuel outlet from a nozzle hole arrangement 15 blocked. On the other hand, is it from its injection valve element seat 14 lifted off, can fuel from the nozzle chamber 6 through in a guide section 16 on the outer circumference of the injection valve element 10 formed axial channels 17 in a plane lower in the drawing plane, radially between the injection valve element 10 and the nozzle body 11 trained annulus 18 at the injection valve element seat 14 over to the nozzle hole arrangement 15 flow and there are essentially injected under the high pressure (rail pressure) standing in the combustion chamber.

From an upper front side 19 the injection valve element 10 and a lower, sleeve-shaped section in the plane of the drawing 20 a plate element 21 becomes a control chamber 22 bounded over a radially in the sleeve-shaped portion 20 of the plate element 21 running inlet throttle 23 with high-pressure fuel from the pressure chamber 6 is supplied. The sleeve-shaped section 20 with enclosed control chamber 22 is radially outwardly surrounded by fuel under high pressure, so that an annular guide gap 24 radially between the sleeve-shaped portion 20 and the injection valve element 10 is comparatively fuel-tight.

The control chamber 22 is about one, in the plate element 21 arranged drainage channel 25 with outlet throttle 26 with a valve chamber 27 connected, the radially outward of a, adjustable in the axial direction, valve sleeve 28 a pressure balanced in the axial direction in the closed state control valve 29 (Servo valve) is limited. From this, fuel can enter a low pressure area 30 of the injector 1 and from there to the injector return port 7 flow when the valve sleeve 28 that with an anchor plate 31 is firmly connected, from its on the plate element 21 trained control valve seat 35 lifted, that is, the control valve 29 is open. For adjusting the valve sleeve 28 in the drawing plane upwards is an electromagnetic actuator 32 with electromagnet 33 provided with the anchor plate 31 standing in an anchorage room 34 is arranged, cooperates and in the consequence also with the valve sleeve 28 , When energizing the actuator 32 raises the valve sleeve 28 from her on the plate element 21 arranged, designed in this embodiment as a flat seat control valve seat 35 from. The flow cross sections of the outlet throttle 23 and the outlet throttle 26 are matched to one another in such a way that when the control valve is open 29 a net outflow of fuel (fuel tax amount) from the control chamber 22 over the valve chamber 27 in the low pressure area 30 of the injector 1 and from there via the injector return port 7 and the return line 8th in the reservoir 3 flows. This reduces the pressure in the control chamber 22 rapidly, causing the injection valve element 10 from its injection valve element seat 14 lifts off, leaving fuel from the pressure chamber 6 through the nozzle hole arrangement 15 can flow out.

To stop the injection process, the energization of the electromagnetic actuator 32 interrupted, causing the valve sleeve 28 by means of a control spring 36 that are on the anchor plate 31 supported, in the drawing plane down to its control valve seat 35 is adjusted. The through the inlet throttle 23 in the control chamber 22 inflowing fuel ensures a rapid pressure increase in the control chamber 22 and thus for one on the injection valve element 10 acting closing force. The resulting closing movement of the injection valve element 10 is from a closing spring 37 supported, which at one end at a peripheral federation 38 the injection valve element 10 and at the other end on the lower side in the drawing plane 39 of the sleeve-shaped section 20 of the plate element 21 supported.

To prevent the open control valve 29 from the valve chamber 27 escaping fuel or most of this fuel, through the armature space 34 At the lower side in the plane of the drawing, there is a radial movement in the armature space 34 extending anchor plate 31 flows past, is inside the valve sleeve 28 a trained as a ring channel channel 40 provided, the anchor plate 34 radially inwardly interspersed and in a plane in the drawing upper portion above the anchor plate 31 in the anchor room 34 flows and from there directly through a central channel 41 within an electromagnet arrangement 42 of the electromagnetic actuator 32 in the axial direction to the centric on the front side 43 of the injector 1 arranged injector return port 7 can flow without taking along the large anchor surfaces of the anchor plate 31 to have to flow. Within the central channel 41 that is radially outward of the solenoid assembly 42 is limited, is also the control spring 36 arranged in the axial direction on a plate element 44 with axial channels 45 supported by the fuel to the return line 8th can flow.

On the plate element 44 is supported in the axial direction and a pressure pin 46 starting with a thinner in the drawing level thickened end portion 47 the valve chamber 27 seals in the axial direction upwards. The on the thickened end section 47 acting pressure forces are doing by the pressure pin 46 on the plate element 44 and thus on a front lid 54 of the injector 1 supported. The pressure pin 46 is only in its lower end section 47 thickened trained. In the axial direction, this is followed by a thin section 48 on, up to the plate element 44 zoom ranges. This thin section 48 of the pressure pin 46 bounded radially inside the channel 40 that is radially outward of the valve sleeve 28 and the anchor plate 31 is limited.

With open control valve 29 the fuel first flows into an annulus 49 , which is a lower portion of the valve sleeve 28 surrounds radially outside. This annulus 49 In turn, radially outward and in the axial direction is bounded upward by a component 50 that the valve sleeve 28 on its outer circumference below the anchor plate 31 leads. From the annulus 49 the fuel flows over a hole 51 acting as a radial bore in the valve sleeve 28 is executed in the channel 40 in the plane of the drawing above the thickened end portion 47 of the pressure pin 46 and flows from there in the axial direction further into the central channel 41 , via the injector return port 7 in the return line 8th , The component 50 which the annulus 49 limited, is clamped in the axial direction between the plate member 21 and a screw plate 52 inside the injector body 9 is held by screwing.

To complete aeration of the anchor space 34 to ensure is a throttle 53 provided via the minimum fuel flow, so a minimum subset of the control amount, from the annulus 49 in the anchor room 34 into an area below the anchor plate 31 can flow. Here is the throttle 53 so dimensioned (small cross-section), that by this fuel flow, the switching behavior of the control valve 29 is not or only slightly negatively affected.

QUOTES INCLUDE IN THE DESCRIPTION

This list The documents listed by the applicant have been automated generated and is solely for better information recorded by the reader. The list is not part of the German Patent or utility model application. The DPMA takes over no liability for any errors or omissions.

Cited patent literature

• - EP 1612403 A1 [0002]

Claims (12)

Injector for injecting fuel into the combustion chamber of an internal combustion engine, in particular a common rail injector, having an injection valve element ( 10 ), which depends on the pressure in a control chamber ( 22 ) is adjustable between a closed position and an open position in the axial direction, wherein the control chamber ( 22 ) by means of an adjustable valve sleeve ( 28 ) having control valve ( 29 ) with an injector return port ( 7 ) is connectable, and wherein the valve sleeve ( 28 ) with an anchor plate ( 31 ) is operatively connected, for adjusting the valve sleeve ( 28 ) with an electromagnetic actuator ( 31 ) cooperates, characterized in that within the valve sleeve ( 28 ) an axially extending channel ( 40 ) is arranged by the fuel with open control valve ( 29 ) from the control chamber ( 22 ) on the inside of the anchor plate ( 31 ) to the injector return port ( 7 ) can flow. Injector according to claim 1, characterized in that the control valve ( 29 ) is formed in the closed state as a pressure-balanced valve in the axial direction. Injector according to one of claims 1 or 2, characterized in that the injector return port ( 7 ) centrically on a front side ( 43 ) of the injector ( 1 ) is arranged. Injector according to one of the preceding claims, characterized in that the channel ( 40 ) in an anchor plate ( 31 ) receiving armature space ( 34 ) or in an adjacent to the anchor space ( 34 ) arranged central channel ( 41 ) in an electromagnet arrangement ( 42 ) of the actuator ( 32 ) opens. Injector according to one of the preceding claims, characterized in that radially inside the valve sleeve ( 28 ) a pressure pin ( 46 ) arranged as one of a control valve seat ( 35 ) having plate element ( 21 ) is formed separate component. Injector according to claim 5, characterized in that the channel ( 40 ) than radially between the valve sleeve ( 28 ) and the pressure pin ( 46 ) arranged annular channel is formed. Injector according to one of claims 5 or 6, characterized in that the pressure pin ( 46 ) a thickened end portion ( 47 ), which the valve sleeve ( 28 ) closes high pressure-tight in the axial direction, and that the thickened end portion ( 47 ) in the axial direction a thin section ( 48 ) connecting the channel ( 40 ) bounded radially inward. Injector according to one of claims 5 to 7, characterized in that the pressure pin ( 46 ) in the axial direction at one with at least one axial channel ( 45 ), in fuel flow direction before the injector return port ( 7 ) arranged plate element ( 44 ) is supported. Injector according to one of the preceding claims, characterized in that the valve sleeve ( 28 ) in a control valve seat ( 35 ) facing lower portion radially outward of an annulus ( 49 ) is surrounded, in which the fuel with open control valve ( 29 ) from an area within the valve sleeve ( 28 ), and that the annulus ( 49 ) with the channel ( 40 ) is hydraulically connected. Injector according to claim 9, characterized in that the annular space ( 49 ) via a, in particular as a radial bore, bore ( 51 ) in the valve sleeve ( 28 ) with the channel ( 40 ) connected is. Injector according to one of claims 9 or 10, characterized in that the annular space ( 49 ) of a the valve sleeve ( 28 ) on its outer periphery leading component ( 50 ) is limited. Injector according to one of claims 9 to 11, characterized in that the annular space ( 49 ) via a throttle ( 53 ) directly with an anchor space ( 34 ) is hydraulically connected, in which the with the valve sleeve ( 28 ) Actively connected anchor plate ( 31 ) is arranged.