KR20180034264A - Method for controlling switchable valves, in particular injection valves of an internal combustion engine of a motor vehicle - Google Patents

Abstract

The present invention relates to a control method of a switchable valve, in particular an injection valve of an internal combustion engine of a vehicle. The switchable valve comprises: a valve needle (20) having a valve seat (26); an upper stopper (22) disposed in the valve needle (20); and a lower stroke stopper (16) for an armature (14) disposed in the valve needle (20) and guided between the stoppers (22, 16) in an axial direction against the valve needle (20) to be displaceable. A restoring force (32) directed to the lower stroke stopper (16) is applied to the armature (14). Particularly, when a valve is closed, the armature (14) is stopped as much as possible at the upper stopper (22) by additional control pulses (415, 420) after a first bounce from the lower stroke stopper (16), moved toward the lower stroke stopper (16) by the restoring force (32) after the additional control pulses (415, 420) are terminated and reaches the lower stroke stopper (16) with correspondingly reduced kinetic energy.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a controllable valve, and more particularly to a control method of an injection valve of an internal combustion engine of an automotive vehicle. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a control method of a switchable valve, in particular an injection valve of an automotive internal combustion engine, according to the preamble of claim 1. Objects of the present invention are computer programs, machine readable data carriers for storage of computer programs and electronic control devices enabling the method according to the invention to be carried out.

In the Automotive Technology Handbook (ISBN 978-3-8384-1440-1), 27th Edition, page 565, Figure 8 shows a switchable solenoid valve for the control of the injection valve or injector, And is injected into the intake pipe of the internal combustion engine. The open and closed positions of the valve needle of the injection valve can be controlled by a solenoid valve so that the injection bores can be opened for injection of fuel. The solenoid valve includes a solenoid armature that is connected to the valve needle to raise the valve needle from the valve seat upon supply of current.

When the injection valve is opened, the solenoid armature collides with the upper stroke stopper so that a sound can be heard. This behavior results in noise generation that adversely affects comfort, so that the current circuit of each injection valve is switched off or blocked for a specified period of time, which is empirically determined just prior to the aforementioned impact of the solenoid armature at the upper stroke stopper , A braking pulse is generated which slows the valve motion. In the case of a control method of a switchable valve suitable for fuel injection, which is known from DE 10 2009 000 132 A1, a braking pulse is generated which slows the valve movement in controlling the valve. The time and / or duration of the braking pulse is preset according to the switching point of the valve. The braking pulse results in a noise reduction effect on the valve switching noise that is substantially dependent on the position and duration of the braking pulse.

A valve structure very similar to gasoline direct injection (GDI) is applied. However, in such a structure, the valve seat must be opened against a much higher pressure than in the case of intake pipe injection. To enable this, in the above structure, as is well known, there are two parts with armature clearance, shown in the Automotive Technology Handbook (ISBN 978-3-8384-1440-1), 27th Edition, An armature is used. A schematic view of this type of valve is also shown in FIG. It can be seen that piezoelectric valves are also used in GDI.

The present invention relates to a method for controlling an armature of an armature in a valve needle, after closing of a valve associated with the present invention, with an armature composed of the two parts described above, The bouncing movement of the body is triggered. During the bounce motion (s) of the armature, the valve needle and the injection valve remain closed, but the armature is not yet in its rest position, which can adversely affect the valve opening process of subsequent injection. In a modern injection system, the control start is more likely to be performed within the time-dependent subsequent bounce interval of the armature, since multiple injections are performed in a relatively short time interval gradually between individual controls. Thus, since the stabilized armature is no longer guaranteed at the start of the individual control, the opening of the valve is delayed or even not performed at all, and the injection quantity correspondingly decreases or is completely missed. Therefore, it is highly necessary to shorten the bounce process of the armature performed after the end of the injection as much as possible.

According to the method according to the invention, after the first bounce from the lower stroke stopper in the valve needle, the armature in the upper stopper in the valve needle is brought to a stop as much as possible by the additional control pulse, Position is moved back toward the lower stroke stopper by the restoring force of the armature spring but reaches there with considerably reduced kinetic energy, so that it is not bounced at all or only slightly bounced from the lower stroke stopper. The additional control pulse therefore corresponds to an "armature stabilization pulse" as a result or effect.

By means of the method according to the invention the bounce process of the armature is considerably shortened so that the armature can be moved in the already shortened control phase and more particularly in the lower control stopper before the subsequent additional control induces a magnetic force to move the armature upwards It is possible to reliably take the stop position. Thereby, a reliable valve function can be ensured even in a relatively short phase time of less than 2 ms. In addition, it is desirable that the above-described modification relates only to the control of the valve only, and that the mechanical or electrical modification of the valve itself is unnecessary.

It should be noted that the additional control pulse is not a braking pulse according to the prior art mentioned at the outset, and the movement of the valve needle and armature remains unchanged upon opening and closing of the injection valve. On the other hand, in order to temporally shorten the subsequent bounce of the armature between the upper stopper and the lower stopper in the valve needle, the armature is intentionally moved toward the upper stopper in the valve needle when the valve is already closed. This is not a known braking pulse for the valve motion, because the motion of the valve needle is thereby not influenced or only slightly affected, thereby being a stabilizing pulse which reduces the subsequent oscillation of the armature. Likewise, the likelihood of detection of the stopping and closing timing of the injection valve is completely obtained from the electrical signal of the injection valve, since the additional control pulse according to the invention is only performed outside the injection valve. However, as a result of the stabilization pulse, the required pause time is significantly reduced until the valve is ready for the next control.

In the method according to the present invention, a configuration may be provided in which a temporary end of the preceding control opening the valve is detected, and a pre-configurable time interval is added to the thus detected temporary end. The appropriate time interval may be determined in advance, for example, at the test bench of the internal combustion engine. An additional control pulse is started at the time of deriving from the addition.

Further, the control duration of the additional pulse may be provided such that the armature is moved towards the upper stopper in the valve needle, but the magnetic force is insufficient to move the valve needle out of the valve seat. As a result, the operating behavior of the valve is affected as little or as little as possible by the additional control pulse.

When the armature is stabilized in its position at the upper stopper in the valve needle, the additional control pulse is terminated so that the armature moves towards the lower stroke stopper due to the restoring force of the armature spring, and there is provided a configuration that is bounced only slightly or not at all have.

By applying a presettable voltage to the solenoid of the valve, a suitable current supply profile can be achieved for further control pulses, a voltage is applied until a preset coil current is reached, The current is regulated in the hysteresis band.

A suitable current supply profile can also be achieved by switching to freewheeling with a freewheeling voltage of 0V at the start of the additional control pulse, in which case the current in the solenoid is again in the solenoid due to the reaction of the existing eddy current to the solenoid of the valve And consequently, the existing magnetic force level does not decrease or decreases only slightly.

A suitable current supply profile can also be achieved in such a way that a pre-settable voltage is applied to the solenoid of the valve until a preset coil current is reached, in which case the residual of the additional control pulse The freewheel voltage of 0V is applied for the duration time.

From the derived current curve, it is determined when the armature reaches the upper stopper at the constant voltage operating phase of the valve, and the duration and / or time curve of the additional control pulse is adapted at the determined time point, A suitable current supply profile can also be achieved in such a manner that additional control pulses are controlled for a duration.

Further, at the constant voltage operating phase of the valve from the derived current curve, the time at which the armature reaches again the upper stopper in the valve needle is determined, the duration and / or time curve of the additional control pulse is adapted at the determined point, A suitable current supply profile can also be achieved through the fact that the current increasing phase of the additional control pulse is terminated within a predetermined interval up to the determined point in time.

The time points referred to in the two paragraphs can also be determined by a method of evaluating the local maximum in the second time derivative of the current curve.

The present invention can be used in a fuel injection system equipped with injection valves with solenoid valves, especially in injection valves provided for direct fuel injection. However, the method according to the invention can only be used with a two-part valve consisting of upper and lower stoppers for the armature in the valve needle and corresponding armature clearance, while the braking pulses practicable according to the prior art are mainly single Of the valve body, only the stroke stopper of the valve body.

The computer program according to the present invention is configured to perform all steps of the method, particularly when the computer program is executed in a computer or in a control device. This enables the implementation of the method according to the invention in one electronic control unit, without having to carry out a structural change of the control unit. To this end, a machine readable data carrier in which a computer program according to the present invention is stored is provided. The computer program according to the invention is executed in an electronic control unit, whereby an electronic control unit according to the present invention, which is configured to control the valve or the corresponding fuel injection system according to the present invention, using the method according to the invention is obtained.

Other advantages and configurations of the invention are set forth in the specification and the accompanying drawings.

The features described above and the features to be described further below can be applied in the form of combinations described herein, as well as in other ways in combination or singularly within the scope of the present invention.

Figure 1 is a schematic cross-sectional view of a solenoid valve known in the prior art of the type associated with the present application.
Figures 2a and 2b show a typical armature stroke and valve needle stroke curve according to the prior art (Figure 2a) and a case in which a stabilization pulse according to the invention is applied (Figure 2b).
Figures 3A-3F illustrate alternative control of a stabilization pulse according to the present invention with corresponding current / voltage curves.
Figure 4 shows an embodiment of a method according to the invention based on a combination of block diagrams / flowcharts.

As already described in DE 10 2009 047 453 A1, Figure 1 shows an element of a solenoid valve 10 which can be used as a injection valve in the injector 11 for direct fuel injection or intake tube injection of an internal combustion engine, . Here, the solenoid valve 10 is closed. A solenoid 12 having an armature 14 is shown. Further, a bushing having an inner pole 18, a cover 34, and an outer pole 30 is disposed around the solenoid. The armature 14 is axially displaceable on the valve needle 20 and includes a lower stopper 16, here a stopper bushing fixedly connected to the valve needle, and an upper stopper 18, here between the stopper ring fixedly connected to the valve needle . An axial clearance, so-called armor free clearance, is provided between the two stoppers 16, 18 on the armature 14 on the valve needle. The armature is held in the lower stroke stopper 16 by the armature spring 32 in a rest state. The valve needle 20 is again pressed against the valve seat 26 interacting with the valve needle 20 by the valve spring 24 so that the at least one injection opening 28 and the injection valve 10 are closed .

Other components of the solenoid valve 10, such as, for example, a fuel channel, are not shown. All related motions are performed in the axial direction which is perpendicular to Fig. It is also envisioned that an open circuit control and / or closed circuit control device 27 having a computer program 29 and a machine readable storage medium 31 used for the control of a solenoid valve 10 according to the method described below, Respectively.

When a current is supplied to the armature coil or the solenoid 12 through the application of the voltage U, the magnetic field surrounding the solenoid is applied to the armature 14, the inner pole 18, the cover 34 and the outer pole 30 . This magnetic field radially bridges the gaps between the bushing having the outer pole 30 and the armature 14 and bridges axially between the armature 14 and the inner pole 18. [ This creates a magnetic force effect on the armature 14 so that the armature 14 moves in the direction of the inner pole 18, that is, upward with respect to the drawing. Thereby, first, the armature 14 is accelerated from its lower stroke stopper 16 toward the upper stopper 22 in the valve needle. As soon as the armature reaches the upper stopper 22, the magnetic force acts on the valve needle even upward. In addition, a force generated between the armature 14 and the upper stopper 22 due to the elastic collision also acts on the valve needle 20 in the opening direction. As a result, the valve needle 20 is separated from the sealing sheet 26 and the injection is started. As a result, the armature 14 and the valve needle jointly continue to move upwardly against the preloading of the valve spring 24 until the armature impacts on the upper stroke stop formed by the inner pole 18. [

Through the transfer of kinetic energy from the armature onto the valve needle, the force acting on the valve needle significantly exceeds the magnetic force acting on the armature 14 at the start of the opening process. A prerequisite for sufficient support of the opening process is that the armature clearance is designed to be sufficiently large or to be precisely dimensioned. If the armature clearance is designed to be too short in dimension, the apparently too short armature pulse is insufficient to reach the upper stopper 22 in the valve needle in order to lift the valve needle 20 out of the valve seat by interaction with the magnetic force Do. Also, when the armature clearance is designed to be too short, the armature reaches the upper stopper 22 too early, so that the magnetic force that has increased until then is smaller than when the armature clearance is designed to be precisely dimensioned. Consequently, in this case, even after the armature 14 collides with the upper stopper 22 in the valve needle, the valve is kept closed until the magnetic force alone is sufficient to lift the valve needle from the seat. In this way, incorrectly dimensioned valves are opened much later than expected, or even when the control duration is too short, they are not even opened.

At the end of the control, the current in the solenoid 12 is cleared. This is typically accomplished by so-called fast erase where a high negative voltage is applied to the coil. Thereby, the coil current and the magnetic force are erased very quickly. Thereby, the magnetic force is rapidly reduced, and the valve needle 20 is returned again by the pre-pressurized valve spring 24 until the valve needle 20 reaches the valve seat 26 again, in cooperation with the armature. Accelerates downward and stops there, thereby ending the injection. At the moment the valve needle reaches the valve seat, the armature 14 is still located in the upper stopper 22 in the valve needle 20 and has considerable pulses directed downward. Since the upper stopper 22 in the valve needle can not apply an upwardly directed force to the armature 14, the armature moves further downward until it reaches the lower stopper 16 in the valve needle.

As is well known, in relation to the movement of the solenoid valve described above during the opening and closing of the solenoid valve, a ballistic operation in which the armature 14 does not reach the inner pole 18, ) Are distinguished from each other. Further, the operation of the valve associated with the present embodiment is directed to the so-called "combustion period" of the internal combustion engine on which the present invention is based, the combustion cycle including, for example, two rotations of the crankshaft in a four- The strokes correspond to suction, compression of the fuel air mixer, expansion of the piston based on combustion, and discharge of combustion byproducts from each cylinder.

After the valve is closed, the armature 14 firstly moves downwardly until it reaches the lower stopper 16 in the valve needle 20 first. Due to the high pulse of the armature, the armature is bounced there and moves upwards again until the valve reaches the upper stopper 22 in the valve needle 20 again. However, upon reaching the upper stopper 22, the armature pulse is coupled with a magnetic force that is negligibly low at this point, insufficient to lift the valve needle 20 back from the valve seat 26 again. Rather, the pulse is reflected back therefrom, resulting in a further reciprocating bounce between the stopper ring 22 and the stopper bushing 16. Since the individual collision processes between the armature 14 and the respective engagement stoppers 16 or 22 are not elastic up to 100% each, rather a little loss is involved, kinetic energy is released from the armature in each collision process, The stopper is stopped at the stopper bushing 22 after a short time. A corresponding stroke curve is shown in Fig. The armature movement is also influenced by the pressure wave or the flow pulsation of the fuel in the valve which is extinguished by the closing process in addition to the influence of the collision process between the armature 14 and one of the two stoppers 16 and 22 . This hydraulic effect allows the armature 14 to be supplied with additional kinetic energy temporarily during the bounce process, which prolongs the duration of the bounce process.

If subsequent control of the valve is performed only after the armature 14 is stopped again, the bounce does not affect the fuel injection. However, in recent internal combustion engines or combustion engines, there is a growing demand for multiple injection systems in which injection systems have relatively short time intervals between controls, preferably with intervals of less than 2 ms between control pulses. In this short interval, a stable armature can no longer be guaranteed at the start of each control.

Due to the bounce process that still continues at the start of control, the position and the motion state of the armature 14 are not defined at this point, and can be significantly changed according to the circumstances and the ambient conditions such as the fuel grade and the fuel temperature. In particular, there may be a situation where the spacing of the armature 14 from the upper stopper 22 in the valve needle 20 is much smaller than the structurally available armature clearance. The valve then responds to the control as described for valves designed to dimension too small of the armature clearance. Particularly critical is that the armature 14 is located at a low speed near the upper stopper, that is, near the stopper ring 22, which in this embodiment represents the upper stopper of the armature 14 in the valve needle . By virtue of the small amount of available exercise clearance until the stopper is reached, the armature 14 can accommodate only a relatively small kinetic energy, thereby causing the valve to behave as if the armature clearance were designed to be too small. Thereby, the opening of the valve is delayed or even not executed, and the injection amount is correspondingly reduced or completely eliminated. Therefore, it is necessary to shorten the bounce process of the armature 14, which is performed after the end of the injection, as effectively as possible.

Figures 2a and 2b illustrate an exemplary embodiment of the present invention with respect to the prior art armature stroke (200, 200 ', 200 "or 215, 215' 215" 2B) according to the present invention. The graph shows the comparison of the valve needle stroke (205, 205 ', 205 "or 220, 220', 220" Each stroke in units of [mu m] is shown for time t. The curve shown in Figure 2a is based on the design of the valve with an armature clearance of 40 [mu] m and a valve stroke of 80 [mu] m in total. The illustrated stroke diagrams 200 to 205 " or the bounce process 200 "of the bolt are shown as square wave control pulses 210 (FIG. 2) having an electrical control voltage, reproduced only as a logic signal with control start and control durations, The bounce process 200 "is, in this example, After closed until stable for about 2000㎲ includes five bound exercise.

The curve shown in Figure 2B is based on a valve design with a 40 mu m armature clearance and a total 80 mu m valve stroke for comparison. The illustrated stroke curve 215-220 " of the armature or armature bolt or the bounce process 215 "shown here is the same as the control pulse 225 shown in FIG. 2A, And appears at an additional control pulse or stabilization pulse 230 that follows a predetermined time interval. The stabilization pulse has a control duration of about 200 mu s while the first control pulse 225 has a control duration of about 600 mu s. The bounce process 215 "is performed in this embodiment until the armature is already stabilized for about 1500 [mu] s after closing of the valve needle 20, compared to Fig. 2A, .

The stabilization pulse may have a preset controllable duration, which can be predetermined, for example, at the test stand. Likewise, the stabilization pulse may have a predefinable, predefined control start at a test stand, for example. In this case, the start of the control of the stabilization pulse can be relatively preset for the control start or relative to the control end of the previous control. However, the control start and / or control duration may also be preset, for example, according to a determined or determined reference time point at the end of the previous control of the valve or corresponding fuel injection. In this case, a time point at which the armature reaches the stop position, that is, the first time after the closing of the valve needle 20 to the stopper bushing 16 again according to the embodiment of the valve shown in Fig. 1, is determined as the reference time point. This reference point can be determined in the preceding combustion cycle without the stabilization pulse. Once this point in time is recognized, the start of control of the stabilization pulse can be determined relative to this point in time, which can preferably be adjusted to case-by-case armature motion. The start of the control of the stabilization pulse is performed before or after the reference time mentioned above, which can be preset or preliminarily experimentally detected, thereby enabling the stabilization pulse to optimally affect the bounce process, . Alternatively, the time at which the valve needle 20 is closed following the preceding control may be determined as the reference time point. The aforementioned termination of the preceding control of the valve or the corresponding injection end can be determined from the already existing mechanical property data of each internal combustion engine or each injection valve / injector, for example data and signals present in the injector characteristic curve and in the control device Can be determined with reference to curves.

Figures 3A-3F illustrate six alternative control profiles or current supply profiles for generating stabilization pulses in accordance with the present invention, and more specifically corresponding current / voltage curves (I, U).

3A, the current supply profile for the stabilization pulse is first applied to the solenoid 12 of the valve with a boost voltage U _{boost that} is higher than the in-vehicle electrical system voltage U _batt of the assumed motor vehicle, Lt; RTI ID = 0.0 > 300 < / RTI > This voltage is applied until a preset boost current (I _boost ) 320, which is less than the current set during normal control, is reached. After reaching the boost current I _boost 320, the in-vehicle electrical system voltage U _batt and the freewheel voltage are pulsed (305, 310, 315) to the solenoid 12, Is adjusted within the hysteresis band 340 shown for the remaining duration of the stabilization pulse. The resulting coil current is insufficient to raise the valve needle from its seat but the armature 14 is not bounced from the upper stopper 22 in the valve needle 20 or is only slightly bounced there and is stabilized just before the end of the stabilization pulse .

In the embodiment shown in FIG. 3B, when the in-vehicle electrical system voltage U _batt instead of the boost voltage U _boost 300 shown in FIG. 3A reaches a preset current level I _boost 365 To the solenoid 12 (345). 3A, the in-vehicle electrical system voltage U _batt and the freewheel voltage are applied to the solenoid 12 in a pulsed manner (350, 355, 360), so that the coil current 370 reaches the remaining duration of the stabilization pulse Lt; RTI ID = 0.0 > 380 < / RTI >

Instead of adjusting the hysteresis band 340 according to FIGS. 3A and 3B, a freewheel voltage of about 0 V is applied from the arrival of the preset current level I _boost 383 for the remaining duration of the stabilization pulse according to FIG. (382).

In the embodiment shown in Fig. 3d, similar to Figs. 3A and 3B, a predetermined voltage is applied to start control of the stabilization pulse, wherein a freewheel voltage 384 of about 0V is used as the preset voltage. Through the reaction of the still existing eddy current, the coil current 385 again increases from the time when the freewheel voltage is applied, and the magnetic force level still existing at this point does not substantially decrease or only decreases very slowly. In particular, the magnetic force reduction is performed much slower than in the case of operation without stabilization pulse.

As can be seen in Figures 3e and 3f, from the current curves 388 and 392 at the operating phase (0V in-vehicle electrical system voltage or freewheel voltage) with constant voltages 387 and 391, The armature motion h _A (386, 390) shown in ordinate is transferred from the lower stroke stopper 16 (stopper bushing) in the valve needle 20 back to the upper stopper 22 in the valve needle 20 after the bounce. (389, 393) reaching the stopper ring (stopper ring) is determined. In this case, the armature 14 is generated by collision with the upper stopper 22 in the valve needle 20 and is directed upwardly to the inflection points 389 and 393 of the current curves 388 and 392, 2 corresponds to the local maximum value of the time derivative (d ² l / dt ²⁾ is used. Knowing this point in time, the duration or progress of the stabilization pulse is controlled in such a way that the stabilization pulse is controlled for a presettable residual duration from this point in time, or the current increasing phase of the stabilization pulse is terminated within a presettable interval up to this point Lt; / RTI >

Using the method described, the stabilization pulse can be adjusted very precisely to the case-by-case behavior of the armature for each valve.

Figure 4 illustrates an embodiment of control logic or routines for implementation of the described method in a block diagram / flowchart combination. In this case, it is first detected and / or determined or stored (400) as to when the preceding control or the corresponding preceding injection process for opening the valve ends. Alternatively, the detection may be performed in a time advance combustion cycle of the internal combustion engine, wherein the derived value corresponds correspondingly, for example to a corresponding time value (e.g. according to FIG. 3) Referring to the crankshaft angle value of the crankshaft. Based on this detected end of injection 400, a pre-settable time interval 405 is added 410, and an additional control pulse is initiated 415 at a later time to be derived at this time, Induces a temporary re-increase of the magnetic force acting on the armature, which is described in 2, and the magnetic force may be generated without the presence of the stabilization pulse relative to the magnetic force curve.

The control duration of the additional control pulse is selected such that the armature 14 is pulled by the temporarily increased magnetic force to the upper stroke stopper 22 in the valve needle or stop ring shown in Figure 1, Is insufficient to raise the valve needle 20 from the valve seat 26. Thereby, the armature does not bounce or bounce slightly from the stopper ring.

As soon as the armature 14 is stabilized at its position in the stop ring, an additional control pulse is terminated (420) in this embodiment, whereby the armature is moved through the armature spring 32 shown in FIG. 1 to the valve needle or stopper And moves to its stop position at the lower stroke stopper 16 in the bushing. Because the armature 14 reaches the lower stroke stopper 16 in the valve needle 20 with relatively small kinetic energy or pulses due to the stabilization performed previously, the armature is not bounced there or only slightly bounces from there.

As a result, the duration between the end of injection and the arrival of the stop position of the armature and the retention of the armature at the stop position is significantly shortened, whereby the time interval range in which the valve is reproducible to act is significantly reduced in time By expanding, multiple injections can be performed at shorter time intervals than in the prior art.

The above-described method may be implemented in the form of a control program for the electronic control unit for controlling the internal combustion engine or in the form of one or a plurality of corresponding electronic control units (ECU).

Claims (13)

A method of controlling a switchable valve, the switchable valve comprising a valve needle (20) having a valve seat (26), an upper stopper (22) disposed in the valve needle (20) And a lower stroke stopper 16 for the armature 14 which is axially displaceably guided relative to the valve needle 20 between the stoppers 20 and 16 so that the armature 14 is provided with a lower stroke stopper 16 (32) is applied to the control valve
Upon closing of the valve the armature 14 is brought to a stop at the upper stopper 22 as far as possible by the additional control pulses 415 and 420 after the first bounce from the lower stroke stopper 16 and the additional control pulses 415, The armature 14 moves toward the lower stroke stopper 16 due to the restoring force 32 and reaches the lower stroke stopper 16 with a correspondingly reduced kinetic energy. Control method. The method of claim 1, wherein a temporary end of control to open the valve is detected and / or stored (400), a predefinable time interval (405) is added (410) to the detected or stored temporary end, Characterized in that additional control pulses (415, 420) are initiated (415) at the time of derivation from said addition. 3. A method according to claim 1 or 2, wherein the control duration of the further control pulses (415, 420) is such that the armature (14) moves towards the upper stopper (22), but the magnetic force causes the valve needle 26). ≪ RTI ID = 0.0 > 26. < / RTI > 3. A method as claimed in claim 1 or 2, wherein when the armature (14) is stabilized at its position in the upper stopper (22), the additional control pulse (415, 420) To the lower stroke stopper (16). 3. A method as claimed in claim 1 or 2, wherein, through the application of a presettable voltage to the solenoid (12) of the valve, a suitable current supply profile is generated for the further control pulse (415, 420) And then the coil current is adjusted in the hysteresis zone 340 through the pulsed application of the voltage or the additional voltage during the remaining control duration of the further control pulse 415, Wherein said control means is operable to control said switchable valve. 3. A method as claimed in claim 1 or 2, characterized in that by switching to free wheeling at the start of an additional control pulse, a voltage of substantially 0 V is applied to the solenoid (12) of the valve. 3. A method as claimed in claim 1 or 2, wherein, through the application of a presettable voltage to the solenoid (12) of the valve, a current supply profile suitable for the further control pulse (415, 420) is generated, Is applied until the coil current is reached and then a freewheel voltage of substantially 0 V is applied to the solenoid (12) during the remaining control duration of the further control pulse (415, 420). Way. 6. The method according to claim 5, wherein, at the operating phase of the valve having a constant voltage from the generated current curve, a time when the armature (14) reaches the upper stopper (22) again is determined, And / or the time curve is adapted to the determined point in time, and further control pulses (415, 420) are controlled for a preset remaining time duration from the determined point. 6. The method according to claim 5, wherein, at the operating phase of the valve having a constant voltage from the generated current curve, a time when the armature (14) reaches the upper stopper (22) again is determined, Characterized in that the control signal is adapted to the determined time point and / or the time curve is reached, and the current increasing phase of the further control pulse (415, 420) is terminated within a presettable time interval to the determined point in time . 9. The method according to claim 8, characterized in that, in the determination of the time point, a local maximum is evaluated in a second time derivative of the current curve. A computer program configured to execute all the steps of the method according to any one of claims 1 or 2 and stored in a machine-readable data carrier. 12. A machine readable data carrier having stored thereon a computer program according to claim 11. An electronic control device configured to control a switchable valve, using the method according to any of the preceding claims.

Images