DE102004021540A1 - Fluid injection control valve for internal combustion engine has coaxial variable nozzle valve with separate jets blocked by inner and outer valve bodies with loading spring - Google Patents

Abstract

The fluid injection control valve (1) is connected to a control module (2). It receives high-pressure fuel from a common rail fuel supply system. The injector has a conical nozzle tip (3) with two rows of jets (7,8), blocked respectively by outer (4) and inner (5) coaxial valve needles. A coil spring (26) urges the outer hollow needle towards its open position while closing the inner needle. A piston (24) forces fuel through a channel (19) from a top working chamber (18) to a bottom working chamber (17) above the valve needles.

Description

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

Such a fuel injection valve is out of DE 101 33 434 A1 known and can be used for injecting fuel into a combustion chamber of a diesel internal combustion engine.

This from the DE 101 33 434 A1 known fuel injection valve comprises a nozzle module and control module. The nozzle module is designed as a so-called coaxial vario nozzle, which is designed with a valve inner needle and a valve outer needle. The valve outer needle, which constitutes a hollow needle and serves to guide the valve inner needle, cooperates with a first valve seat for controlling first injection openings. The valve inner needle cooperates with a second valve seat for controlling second injection openings. When the valve needles are actuated by means of the control module, the valve outer needle is initially opened, so that small amounts of fuel can be injected into the combustion chamber via the first injection openings, which have a smaller diameter than the second injection openings. Due to the small diameter of the second injection openings, a good atomization of the fuel can be achieved, whereby more favorable emission values can be implemented. When the internal combustion engine is operated under full load, larger amounts of fuel must be injected into the combustion chamber. This is realized by also opening the valve inner needle and thus releasing the second injection openings with the larger diameter.

At the injection ports facing away faces border the two nozzle needles to a valve control room, in which there is a fluid pressure, over the Control module is set. To open the valve pins is reduces the prevailing in the valve control chamber fluid pressure, so that the respective valve needle by acting on a pressure shoulder High pressure in open position is moved. The opening behavior the two valve pins is dependent from the formation of the pressure shoulders and closing springs, the valve needles in the closing direction of the fuel injection valve Pretension.

at Injectors known from practice are the valve needles associated closing springs in the cooperating with the valve needles control space or respectively a valve needle associated with a closing spring in each case with a arranged a valve needle co-operating control space, thereby the volume of the control room or the volumes of the control rooms in such a way are big, that a rigidity of the valve assembly in undesirable Circumference is reduced. About that In addition, the takes place in a control of the valve needles Pressure reduction in the control room or in the control rooms due to the large control room volumes delayed compared to smaller trained tax havens, which is sustainable the precision an injection process.

In addition is a course of a pressure gradient during a control phase of Injector in the control room or in the control rooms due the big Volumes so flat that an accuracy of the injection process due to component tolerances in the area of the valve seats of the valve needles strong is influenced and the injection openings in case of deviations from either a lot to a predefined diameter of the valve seats early or much later opened as intended which, however, are very detrimental to a combustion process of Internal combustion engine affects.

Advantages of the invention

The inventive valve for controlling fluids, in particular for injecting fuel in a combustion chamber of an internal combustion engine, with the features after the preamble of claim 1, wherein valve between the valve outer needle and with the valve inner needle formed with a tube spring and the valve inner needle at least partially encompassing further Spring device is provided, via which the inner valve needle cushioned against the valve seat of the body associated with the valve inner needle is, has the advantage that a volume of the control room for driving the valve inner needle is dimensioned such that the valve according to the invention is precisely controlled with low reaction times. This can be a Injection process are carried out extremely precisely, because the pressure-controlled movement of the inner valve needle with a small control chamber volume by a steep course of the pressure gradient during one over one Actuator of the valve according to the invention triggered volume change the control room and a resulting pressure reduction marked in the control room.

drawing

An embodiment of a valve according to the invention for controlling fluids is shown schematically simplified in the drawing and will erläu in the following description tert.

The single figure of the drawing shows a highly schematic longitudinal section view a part of a valve according erfindungsge executed for controlling fluids.

description of the embodiment

In the figure is a valve 1 shown for controlling fluids or a fuel injection valve, which is preferably part of a so-called common-rail injection system and for injecting fuel into a combustion chamber of an internal combustion engine of a motor vehicle. The fuel injection valve comprises a control module as essential components 2 and one with the control module 2 co-acting nozzle module 3 for controlling an injection of fuel into the combustion chamber of the internal combustion engine, a valve outer needle 4 and a valve inner needle 5 having.

The valve outer needle 4 and the inner valve needle 5 are coaxial with each other in a nozzle body 6 of the nozzle module 2 arranged and guided longitudinally movable. Here is the valve outer needle 4 in the nozzle body 6 and the inner valve needle 5 in the valve outer needle 4 guided.

Furthermore, the valve outer needle act 4 and the inner valve needle 5 in the region of their combustion chamber facing the combustion chamber ends each with valve seats 4A . 4B respectively. 5A . 5B for driving in the nozzle body 6 trained injection ports 7 . 8th together.

The valve outer needle 4 and the inner valve needle 5 are in a hole 9 of the nozzle body 6 arranged, wherein in egg nem of the valve outer needle 4 and the nozzle body 6 limited annulus 10 via a feed channel 11 and a fuel source, not shown in detail in the figure, fuel is supplied under high pressure. The annulus 10 extends in the embodiment of the fuel injection valve according to the invention shown in the figure 1 from a head piece 12 up to the valve outer needle 4 associated first valve seat 4A of the nozzle body 6 ,

In addition, the annulus 10 via through holes 13 in the valve outer needle 4 with another annulus 14 connected to the valve outer needle 4 and the valve inner needle 5 is limited. That means that via the feed channel 11 high-pressure fuel over the annulus 10 and the through holes 13 in the further annulus 14 between the valve outer needle 4 and the inner valve needle 5 until just before the injection openings 7 and 8th in the nozzle body 6 are trained, is directed.

Furthermore, the valve inner needle 5 with a fuel channel 15 formed, over which the further annulus 14 with a downstream of the valve inner needle 5 associated valve seat 5B between the valve inner needle 5 and the nozzle body 6 trained fuel room 16 in the region of the nozzle of the engine module projecting into the combustion chamber of the internal combustion engine 3 is formed, is connected.

With this embodiment of the fuel injection valve 1 is the over the feed channel 11 High-pressure fuel is supplied from each side to the injection ports 7 and 8th of the nozzle body 6 brought up. In the present case, the term "from both sides" is to be understood as meaning that the fuel is connected to that of the valve outer needle 4 controlled injection openings 7 over the annulus 10 between the nozzle body 6 and the valve outer needle 4 to the first of the valve outer needle 4 associated valve seat 4A and over the further annulus 14 between the valve outer needle 4 and the valve inner needle 5 to the second of the valve outer needle 4 associated valve seat 4B of the nozzle body 6 is led up. The same procedure is for the valve inner needle 5 to be controlled injection openings 8th of the nozzle body 6 provided at which both the first of the inner valve needle 5 associated valve seat 5A and also on the second of the inner valve needle 5 associated valve seat 5B each over the other annulus 14 under high pressure pending fuel and the fuel chamber 16 under high pressure pending fuel is present.

The valve outer needle 4 and also the inner valve needle 5 are in the area of the valve seats 4A . 4B respectively. 5A . 5B with such beveled surfaces 41 . 42 . 43 and 44 respectively. 51 . 52 . 53 . 54 executed, so that both the valve outer needle 4 as well as the valve inner needle 5 in the area of the valve seats 4A . 4B respectively. 5A . 5B each with an over the circumference of the valve outer needle 4 or the valve inner needle 5 extending sealing edge on the nozzle body 6 issue. About thereby between the valve outer needle 4 or the inner valve needle 5 trained line contact is given a high sealing effect between the components. This ensures that an escape of fuel from the fuel injection valve only with a corresponding control via the control module 2 he follows.

Furthermore, the valve outer needle act 4 and valve inner needle 5 each with their valve seats 4A . 4B and 5A . 5B opposite ends with a control room 17 . 18 together, over a connecting channel 19 are connected. The control room 17 is from the end faces of the valve outer needle 4 and the valve inner needle 5, the head piece 12 and one on the valve outer needle 4 out Control chamber sleeve 20 limited.

The control chamber sleeve 20 is about a spring device 21 , which in installation position between a paragraph 22 the valve outer needle 4 and the control chamber sleeve 20 is biased, against the head piece 12 pressed, leaving the control room 17 opposite the annulus 10 of the nozzle body 6 is sealed.

To a bearing surface of the paragraph 22 the valve outer needle 4 for the spring device 21 to enlarge, is between the spring device 21 and the paragraph 22 a washer 23 arranged, whose inner diameter is approximately the outer diameter of the valve outer needle 4 in the area of the paragraph 22 and whose outer diameter is greater than the outer diameter of the paragraph 22 is executed.

Furthermore, the control chamber sleeve 20 in terms of in the annulus 10 during operation of the fuel injection valve 1 prevailing hydraulic pressure balanced, so that on the control chamber sleeve 20 essentially only that of the spring device 21 outgoing pressure force in the direction of the head piece 12 engages, whereby during all operating conditions of the fuel injection valve 1 a secure seal between the annulus 10 and the control room 17 is guaranteed.

The over the connection channel 19 with the first control room 17 connected second control room 18 of the fuel injection valve 1 is from the head piece 12 , a translator piston 24 of the control module 2 and another control chamber sleeve 25 limited. The translator piston 24 acts in a conventional manner with an unspecified in the figure and formed as a piezoelectric actuator actuator, which is made, inter alia, of a layered ceramic material and disposed in an actuator chamber of the control module.

During operation of the fuel injection valve 1 becomes the piezoelectric actuator with the valve seats closed 4A . 4B and 5A . 5B energized so that the booster piston 24 due to the elongation, which is dependent on the energization, about an adjustment path corresponding to the elongation in the direction of the head piece 12 in the axial direction of the fuel injection valve 1 is adjusted relative to a deenergized state of the piezoelectric actuator. Because of this adjustment lies both in the control room 18 as well as the associated control room 17 such a pressure level that both the valve outer needle 4 as well as the valve inner needle 5 against the respective korres pondierenden valve seats 4A . 4B and 5A . 5B of the nozzle body 6 are pressed sealingly.

That in the control rooms 17 and 18 present pressure level is in the operation of the fuel injection valve 1 In addition, depending on between each of the tax havens 17 and 18 delimiting components occurring leakage currents starting from the annuli 10 and 14 and as a function of the currently set via the piezoelectric actuator axial position of the booster piston 24 set.

In addition, in the further annulus 14 ie between the valve outer needle 4 and the valve inner needle 5 another spring device 26 provided by means of the valve inner needle 5 one in the closing direction of the valve inner needle 5 associated injection openings 8th acting force component on the valve inner needle 5 is applied, via the valve outer needle 4 , the spring device 21 and the control chamber sleeve 20 on the head piece 12 is supported.

The spring device 26 is present with an open bourdon tube 27 executed, which between two washers 28A and 28B is arranged, which are designed as slotted spring rings. The washer acts 28A depending on the respective axial position of the valve outer needle 4 or the valve inner needle 5 either with a shoulder 29 the valve inner needle 5 or with an abutment shoulder 30 the valve outer needle 4 together. The washer 28B however, it only works with another shoulder 31 the valve inner needle 5 together, so that at the Ven tilinnennadel 5 attacking and in the opening direction of the valve inner needle 5 acting forces on the washer 28B , the bourdon tube 27 , the washer 28A into the valve outer needle 4 are feasible.

A wall thickness of the Bourdon tube 27 in the present case is about 0.2 mm and is also in one between the shoulders 29 and 31 with respect to a guide diameter D_F of the valve inner needle 5 reduced diameter D_R trained area of the valve inner needle 5 arranged so that the spring device 26 between the valve outer needle 4 and the valve inner needle 5 claimed only little additional space in the radial direction.

The Bourdon tube 27 is presently designed as a cylindrical body, which is designed with recesses in its lateral surface. The recesses lead to an increase in the elasticity of the cylindrical body formed from spring steel, wherein the recess is preferably cut out of the lateral surface via a laser process. Furthermore, the Bourdon tube is in the axial extension of the Bourdon tube 27 running slot, so that the Bourdon tube for mounting in Area of the axially extending slot is expandable such that the Bourdon tube 27 over the guide diameter D_F of the valve inner needle 5 in the area of the inner valve needle formed with the reduced diameter D_R 5 is feasible and then space-saving on the reduced diameter range of the valve inner needle 5 is applied.

The translator piston 24 is driven in this case by the piezoelectric actuator such that the fuel injection valve 1 can be operated in the manner described below.

In the closed state of the injection openings 7 . 8th , That means, when energized accordingly piezoelectric actuator, are both the valve outer needle 4 as well as valve inner needle 5 with their ends facing the combustion chamber respectively at the valve seats 4A . 4B respectively. 5a . 5B of the nozzle body 6 sealingly. This is effected by the fact that the piezoelectric actuator in the energized state, that is, when a voltage is applied to the piezoelectric actuator, in the axial direction has an elongation, which via a not-shown hydraulic or mechanical translation unit to the booster piston 24 is transferred and this in the direction of the head piece 12 shifts that in the control rooms 17 and 18 such a pressure level exists that both the valve outer needle 4 as well as the valve inner needle 5 the corresponding injection ports 7 . 8th opposite to the high pressure in the nozzle body 6 Seal supplied fuel.

If there is a corresponding requirement for the beginning of an injection process, the voltage applied to the piezoelectric actuator voltage is reduced, that sets a spontaneous change in length, ie shortening in the region of the piezoelectric ceramic of the piezoelectric actuator. This change in length causes the booster piston 25 through the in the control room 18 present pressure, which corresponds to the system pressure or the rail pressure and can be up to 1.8 kbar, from the header 12 is moved in the direction of the piezoelectric actuator.

This spontaneous adjustment of the booster piston 24 and the concomitant increase in volume of the control room 18 leads to such a pressure drop in the control rooms 17 and 18 that the inner valve needle 5 from their corresponding valve seats 5A and 5B takes off.

This results from the fact that the on the inner valve needle 5 attacking resultant force component resulting from the on the active surfaces of the valve inner needle 5 attacking hydraulic pressure conditions as well as between the valve outer needle 4 and the valve inner needle 5 arranged spring device 26 composed of the valve seats 5A . 5B the valve inner needle 5 in the direction of the booster piston 24 is directed.

In this operating state of the fuel injection valve 1 is the over the feed channel 11 into the nozzle module 3 high-pressure fuel over the annulus 10 , the through holes 13 the valve outer needle 4 , the other annulus 14 and the injection openings 8th of the nozzle body 6 injected into the combustion chamber of the internal combustion engine.

The spring constant of the spring device 21 is presently greater than the spring constant of the spring device 26 executed, leaving the valve inner needle 5 due to each in the control room 17 and the control room 18 set pressure levels in any case before the Ventilaußenna del 4 and the corresponding valve seats 5A . 5b of the nozzle body 6 takes off.

If there is a request to terminate the Einspitzung starting from the above-described operating state of the fuel injection valve 1 in which the valve inner needle 5 associated valve seats 5A . 5B of the nozzle body 6 are opened, before, the voltage applied to the piezoelectric actuator voltage is increased such that the booster piston 24 again in the direction of the head piece 12 is moved, which in turn a volume reduction and an increase in the pressure level in the area of the control rooms 17 and 18 is effected. By raising the pressure level in the control chambers 17 and 18 engages the valve inner needle 5 a resultant force component that the inner valve needle 5 against the valve inner needle 5 associated valve seats 5A and 5B presses, with what the injection ports 8th from the valve inner needle 5 are closed and the injection is completed.

On the other hand, if the internal combustion engine is in the full load range, the energization of the piezoelectric actuator becomes open when the valve inner needle is open 5 so degraded that the booster piston 24 due to the further change in length or shortening of the piezoelectric ceramic still further from the head piece 12 is moved in the direction of the piezoelectric actuator. This will set the pressure level in the control rooms 17 and 18 , which was previously already reduced from the system pressure or rail pressure, lowered even further, so that both the valve inner needle 5 as well as on the valve outer needle 4 one in Publ tion direction of the valve needles 4 . 5 acting resultant force component is applied and the valve outer needle 4 associated valve seats 4A . 48 of the nozzle body 6 from the valve outer needle 4 be released.

In this operating state, the via the feed channel 11 into the nozzle module 3 High pressure fuel directly from the annulus 10 over the injection openings 7 and 8th of the nozzle body 6 injected into the combustion chamber of the internal combustion engine, wherein the now in the combustion chamber einbringbare fuel flow is greater than that previously via the injection openings 8th in the combustion chamber injected fuel flow, as the diameter of the valve outer needle 4 controllable injection openings 8th of the nozzle body 6 greater than the diameter of the valve inner needle 5 controllable injection openings 8th of the nozzle body 6 ,

Based on this operating state of the fuel injection valve 1 There is now the possibility of the injection process by a corresponding energization of the piezoelectric actuator and an associated complete closing fuel injection valve 1 to end. Alternatively, however, there is also the possibility to energize the actuator such that only those via the valve outer needle 4 controllable injection openings 7 with a reduced fuel flow through the injection ports 8th continue.

The nozzle body 6 is in the area between the annulus 10 and the through holes 13 the valve outer needle 4 at its the valve outer needle 4 facing inside with three flat areas or flats 32 executed. Furthermore, the valve outer needle 4 at her the nozzle body 6 facing outside in the area of the flats 32 of the nozzle body 6 also with three with the flats 32 co-operating flat polished edges 33 running, so that the over the feed channel 11 and over the annulus 10 high-pressure fuel from the annulus 10 about the between the flattenings 32 and the cuts 33 formed spaces with less flow resistance to the through holes 13 the valve outer needle 4 is feasible.

The above-described embodiment of the invention a nozzle module a fuel injection valve or a valve for controlling liquid is in principle also known with other from the prior art Control modules combined and provides regardless of the selected embodiment the control module is a very compact solution, the in the drawing illustrated fuel injection valve, which is directly controlled is and a so-called servo injector, particularly suitable is to avoid the disadvantages known from the prior art.

Claims (11)

Valve ( 1 ) for controlling fluids, in particular for injecting fuel into a combustion chamber of an internal combustion engine, with a control module ( 2 ), the one on a booster piston ( 24 ) Actuator, and one with the control module ( 2 ) cooperating nozzle module ( 3 ), which controls an injection valve of fuel, a valve outer needle ( 4 ) and a valve inner needle ( 5 ), which in a nozzle body ( 6 ) are arranged and longitudinally movably guided and which in each case at its end remote from the combustion chamber with a valve control chamber ( 17 . 18 ) connected to the booster piston ( 24 ) and whose pressure level depends on the position of the booster piston ( 24 ) is adjustable, and with their combustion chamber facing areas with valve seats ( 4A . 4B and 5A . 5B ) and their associated injection openings ( 7 . 8th ) of the nozzle body ( 6 ), wherein at least the valve outer needle ( 4 ) via a spring device ( 21 ) against the valve outer needle ( 4 ) associated valve seat ( 4A . 4B ) of the nozzle body ( 6 ) is spring-loaded, and wherein the spring device ( 21 ) at the nozzle body ( 6 ) facing outer surface of the valve outer needle ( 4 ) between the valve outer needle ( 4 ) and the nozzle body ( 6 ) is provided, characterized in that between the valve outer needle ( 4 ) and the valve inner needle ( 5 ) one with a bourdon tube ( 27 ) and the inner valve needle ( 5 ) at least partially enclosing further spring device ( 26 ) is provided, via which the inner valve needle ( 5 ) against the valve inner needle ( 5 ) associated valve seat ( 5A . 5B ) of the nozzle body ( 6 ) is sprung. Valve according to claim 1, characterized in that the bourdon tube ( 27 ) on the valve inner needle ( 5 ) is disposed in a reduced diameter area (D_R). Valve according to claim 1 or 2, characterized in that between the bourdon tube ( 27 ) and the valve inner needle ( 5 ) and between the bourdon tube ( 27 ) and the valve outer needle ( 4 ) one washer each ( 28A . 28B ) is provided. Valve according to claim 3, characterized in that the washers ( 28A . 28B ) are designed as slotted spring rings. Valve according to one of claims 1 to 4, characterized in that the control room ( 17 ) from a head piece ( 12 ), the inner valve needle ( 5 ), the valve outer needle ( 4 ) and a control chamber sleeve ( 20 ) is limited. Valve according to claim 5, characterized in that the control chamber sleeve ( 20 ) about one at the Valve outer needle ( 4 ) supported spring unit ( 21 ) against the head piece ( 12 ) is pressed. Valve according to claim 5 or 6, characterized in that the control chamber sleeve ( 20 ) on the valve outer needle ( 4 ) is guided. Valve according to one of claims 1 to 7, characterized in that both the valve inner needle ( 5 ) as well as the valve outer needle ( 4 ) each with two valve seats ( 5A . 5B respectively. 4A . 4B ) of the nozzle body ( 6 ), wherein in each case between two of a valve needle ( 4 or 5 ) associated valve seats ( 4A . 4B or 5A . 5B ) Injection openings ( 7 or 8th ) are arranged. Valve according to one of claims 1 to 8, characterized in that a spring constant of the control chamber sleeve ( 20 ) associated spring device ( 21 ) greater than a spring constant between the valve inner needle ( 5 ) and the valve outer needle ( 4 ) arranged further spring means ( 26 ). Valve according to one of claims 1 to 9, characterized in that the valve outer needle ( 4 ) with at least one through-bore ( 13 ) is executed, via the one of the valve outer needle ( 4 ) and the valve inner needle ( 5 ) limited area ( 14 ) with a high pressure area ( 10 . 11 ) connected is. Valve according to one of claims 1 to 10, characterized in that the nozzle body ( 6 ) in a contact area for the valve outer needle ( 4 ) at least in regions with at least one flattening ( 32 ), which has at least one bevel ( 33 ) of the valve outer needle ( 4 ) cooperates in such a way that under high pressure into the nozzle body ( 6 ) supplied fuel between the flattening ( 32 ) and the bevel ( 33 ) in the through hole ( 13 ) of the valve outer needle ( 4 ) is feasible.