DE102005059176A1 - Armature bouncing recognizing method for e.g. fuel valve, involves verifying whether actual flow characteristics correspond to reference-flow characteristics, and exposing anchor bouncing, when both characteristics do not correspond - Google Patents

Abstract

The method involves assigning reference-flow characteristics to a solenoid valve (1). An actual flow characteristic is recorded and verified, whether the actual flow characteristics correspond to the reference-flow characteristics. An anchor bouncing is exposed, when the actual flow characteristics do not correspond to reference-flow characteristics. The characteristics of the anchor bouncing are recognized independent of the initial-flow characteristics, where the bouncing characteristics comprise of stroke level of the bounced anchor, and duration and frequency of the anchor bouncing. Independent claims are also included for the following: (1) a control device for controlling a solenoid valve (2) a computer program which runs in a control device for controlling a solenoid valve.

Description

State of technology

The The invention relates to a method for detecting an armature bounce in a solenoid valve.

The Invention also relates to a control device for controlling a solenoid valve, wherein the solenoid valve has an armature.

The The invention further relates to a computer program that is used in a computing device, in particular in a control unit to control a solenoid valve runs.

One An armature exhibiting solenoid valve is known from the market. It is designed, for example, as a fuel valve and comprises a valve element which cooperates with a valve seat and a flow path can release or lock a fluid. The valve element is Electromagnetically actuated. For this purpose, a magnet armature or armature is coupled to the valve element. The anchor is housed in an anchor space around which one Magnetic coil is arranged. By a valve spring, the valve element and thereby also the armature is pressed into an electroless end position. In this end position is the flow path the fluid is blocked.

By an electrical current supply of the surrounding the armature space magnetic coil can the armature and the valve element are moved against the force of the spring become. For this purpose, the anchor is in particular an anchor plate assigned, wherein the magnetic force of the energized solenoid such acting on the armature plate that these are in the direction of the magnetic coil emotional. The anchor plate is in this case positively connected to the anchor, that the armature counteracts due to the movement of the anchor plate the force of the valve spring moves. This in turn causes the flow of the fluid is released.

One Such solenoid valve is, for example, in an injector for the fuel metering used in an internal combustion engine. The amount and the time The metering of the fluid or the fuel takes place in dependence from the energization of the solenoid valve.

In many applications are as short as possible distances desired between individual metering. For example, can in an internal combustion engine a particularly uniform and efficient combustion of the metered fuel by so-called Pre-injections done. This will be low in very short time intervals Metered amounts of fuel.

ends the energization of the solenoid valve, so the anchor is by the force a valve spring acted upon such that a valve ball a Flow restrictor closes. By closing, in particular by the impact of the valve ball against the seat the flow restrictor, the anchor can be in indefinitely Get vibrations.

Further By the end of the energization, the armature plate can oscillate devices. Such vibrations are referred to as anchor bounces. The Anchor bounce impaired the metering accuracy, especially in multiple injections with very short injection intervals.

Around an increased Zumessgenauigkeit to obtain it is known, the anchor bounce means a suitable sensor, for example one on the solenoid valve attached eddy current sensor, detect and depending a detected anchor bounce the solenoid valve to control such that In the following injections sufficient Zumessgenauigkeit can be achieved.

It It is therefore an object of the invention to provide a method for detecting the Create anchor bounce, which is less complicated to implement and doing an increased Reliability against usual Procedure offers.

The Task is solved by that the solenoid valve at least assigned a desired Strommerkmal becomes, an actual electricity feature is recorded, checked, whether the actual electricity feature corresponds to the desired current characteristic and closed to an anchor bounce If the actual Strommerkmal not only insignificant of the Target current characteristic deviates.

Advantages of invention

The inventive method has the advantage of being there for already existing solenoid valves can be used without that these would have to be changed structurally in some way. In order to will also be the opportunity prevents failure, since no additional component in the form of a sensor must be used.

to execution the method according to the invention only the actual current characteristic is detected and compared with the desired current characteristic. This For example, by means of the control unit, which the solenoid valve controls, performed become. The inventive method to detect the anchor bounce is so with little effort and cost-effective realizable.

A movement of the armature always has a change in the inductance in the solenoid valve arranged solenoid coil result. The inductance in turn acts on the current flow of the current supply of the solenoid valve.

One Soll-Strommerkmal can be, for example, the current to a certain time during the energization of the solenoid valve flows through this, under the condition that no anchor bounce occurs. The actual electricity feature can actually describe current flowing through the solenoid valve at this time. Complies the actual measured current at this time, ie the actual current characteristic, not the expected current, so the target Strommerkmal, so is according to the invention on the Presence of an anchor bounce closed. This is possible because the anchor undergoes a movement by the anchor bouncing, the a change the inductance the solenoid coil has the consequence and thus a deviation of the actual by the Solenoid valve flowing Electricity causes. This can be provided in particular that only then an anchor bounce is closed when the deviation is sufficiently significant. This can on the one hand measurement inaccuracies considered and on the other hand so that only such armature movements identified as anchor bounce which exceeds or exceeds a certain minimum lift or frequency. below.

According to one advantageous embodiment the desired current characteristic and the actual current characteristic with respect to a pre-energizing determined. In this embodiment, therefore, the Solenoid valve before activation with the so-called attraction current with a bias current applied. This bias current is chosen such that the solenoid valve still does not attract, but already a change of Vorstroms due to an inductance change within the solenoid possible is, so that due to such a change in the bias current on the Presence of an anchor bounce can be closed. Is by means of the pre-energizing detected an anchor bounce, so may in the subsequent metering the presence of the anchor bounce must be taken into account.

According to one another advantageous embodiment are the desired current characteristic and the actual current characteristic with respect to a Recharging current determined. To respond as quickly as possible Solenoid valve, the solenoid valve is in the opening phase first driven by a current with a steep, well-defined Flank, for example, rises to about 20 A. For this is a so-called booster voltage used, which generates in the control unit and in a capacitor, the so-called boost voltage storage, is stored. The recharge of the booster voltage memory happens by means of a recharging current.

is the solenoid valve opened, so it is operated in a so-called holding current phase, wherein the stream opposite the opening phase and the suit phase is lowered. The opening phase describes the Phase while an energizing the solenoid valve begins, usually with a Current that has a steeply rising edge, but not yet Movement of the anchor is done. In the suit phase a movement takes place of the armature due to the continued energization of the solenoid valve.

at lowering the current during of the transition Energy is released for the holding current phase. This is the booster voltage memory fed in the form of a recharging. In particular, already is at the beginning of one on the opening phase following tightening phase in the opening phase of the booster voltage storage withdrawn removed energy. This happens until the original Energy potential is reached, which is necessary for opening the solenoid valve is. A change the inductance the solenoid thus affects the recharging current. is for the Recharge current a desired current characteristic determines and a corresponding actual current characteristic is determined, so is also from this the presence or absence of an anchor bounce recognizable.

Preferably is the desired current characteristic by means of a desired current waveform and / or the actual current characteristic obtained by means of an actual current profile. The desired current characteristic and the actual current characteristic will consequently be within the time course a predetermined period described. This can be, for example done by means of a characteristic. Such a characteristic can for example, the for a certain metering intended energization of the solenoid valve describe. For this purpose, the actual by the solenoid valve flowing Electricity measured. Diverge from the desired current profile, for example by an oscillation corresponding to the anchor bouncing or by the Anchor bounce is induced, so may indicate the presence of an anchor bounce getting closed. The desired current profile and the actual current flow can become also refer to the Vorbestromung or on the Nachladestrom.

advantageously, becomes dependent the actual current characteristic detected at least one feature of the anchor bounce. It will therefore not only an anchor bark recognized, but it is by means of of the current flow characteristic is a qualitative feature of the anchor bounce recognized. This allows for example dependent on the quality the anchor bounce suitable measures to compensate for the anchor bounce and thus to increase the metering accuracy to take.

advantageously, the feature describes the lift height of the bouncing anchor, a duration of the anchor bounce, or a frequency the anchor bounce. This is a particularly sensitive reaction to the Presence or quality a present anchor bounce possible. A duration of the anchor bounce can be recognized, for example, by determining the time will, while the desired current characteristic, For example, the desired current profile, always a specifiable Amount of the actual current characteristic, for example the actual current profile, different. It may then be provided, for example, an opening of the Solenoid valve by energizing to bring back only when the anchor bouncing is no longer present.

is the characteristic as the lifting height formed of the bouncing anchor, it can be provided only then again to cause energization of the solenoid valve when the lifting height falls below a predefinable value.

A Frequency of the anchor bounce can also be used for deciding if a Energization of the solenoid valve should be used. This can be dependent be made of whether in the present solenoid valve rather a high Frequency of the anchor bounce or rather a low frequency of the Anchor bounce a particularly negative impact on the metering accuracy exercises.

The Invention is also by a control device of the type mentioned solved by that the controller Means of implementation the method according to the invention having. This makes it possible Detect the anchor bounce by means of the existing control unit and also by means of the controller to a recognized anchor bouncing such to respond, that the energization, by means of which the metering quantity controlled will be adjusted accordingly.

From Of particular importance is the realization of this invention in the form a computer program. The computer program is on one Computing device, in particular on a control unit for the Control of a solenoid valve, executable and to perform the inventive method programmed. The invention is thus the computer program realized, so that this computer program in the same way the Invention represents how the method for its execution of Computer is suitable.

The Computer program is preferably stored on a memory element. A memory element can in particular be a random access memory, a read-only memory or be a flash memory. A memory element can in particular also a floppy disk, a compact disc, a digital versatile disc and / or at least one memory area allocated to a component of the computing device be.

drawings

Further applications and advantages of the invention will become apparent from the following description of exemplary embodiments, which are shown in the drawing. Show it:

1 a schematic representation of a solenoid valve as part of a fuel injector;

2 a schematic representation of the armature stroke of a bouncing anchor as a function of time; and

3 a schematic representation of a current profile with Vorbestromung for driving a solenoid valve.

description the embodiments

In 1 is a solenoid valve 1 For example, shown as part of a fuel injector, not shown. The solenoid valve 1 has a valve body 2 in which an anchor room 3 is trained. In the anchor room 3 is an anchor 4 arranged, an anchor plate 5 having. In the anchor room 3 are also an overstroke spring 6 and a solenoid valve spring 7 arranged.

The solenoid valve 1 also has a magnetic coil 8th on which the solenoid valve spring 7 encloses annularly.

A valve ball 9 sits in a at an upper end of a drain throttle 10 trained valve seat. The outlet throttle 10 opens into a valve control room 11 ,

Will be to the solenoid 8th via electrical lines, not shown, an electric current, so there is a so-called energization of the solenoid valve, it is in the solenoid 8th built up a magnetic field, which is a movement of the armature 4 upwards against the force of the solenoid valve spring 7 causes. Is the solenoid valve 1 , as in 1 indicated, part of a fuel injector, so causes a valve in the control room 11 prevailing pressure of a fuel located there a movement of the valve ball 9 from the valve seat, as in a fuel injector in the valve control room 11 prevailing pressure is higher than that in the anchor space 3 prevailing pressure.

Of importance for the present invention is that an energization of the solenoid valve 1 a Movement of the anchor 4 The result is an air gap 12 between the anchor plate 5 and the magnetic coil 8th , which is represented by the dashed lines labeled A and B, decreases. Furthermore, the anchor emerges 4 through this movement partly into through the magnetic coil 8th formed ring. This has, like every movement of the anchor 4 , a change in the inductance of the solenoid 8th result.

At a transition from an open state of the solenoid valve 1 in a closed state of the solenoid valve 1 , as in 1 typically armature bounce occurs when the armature 4 characterized in its closing movement is stopped, that the valve ball 9 pressed into the valve seat. The anchor 4 Attempts the kinetic energy by moving in the opposite direction, ie towards opening the solenoid valve 1 to dismantle. Here, however, the force of the solenoid valve spring acts 7 against the movement of the anchor 4 , This will be the anchor 4 again against the valve ball 9 and pressed them into the valve seat. A repetition of this movement is called anchor bounce.

In 2 the time profile of the anchor stroke is exemplified. At a time T0 causes the control unit, the energization of the solenoid valve. This is done by the solenoid 8th built up a magnetic field. This causes a movement of the anchor plate 5 and the anchor 4 in the direction of the magnetic coil 8th , The armature stroke could be measured, for example, in microns. In this first energization phase of the solenoid valve 1 the air gap decreases 12 about 27 μm with respect to the zero line.

At a time T1 causes the controller, the energization of the solenoid valve 1 to interrupt. The anchor 4 then moves due to the force acting on this solenoid valve spring 7 back in the 1 illustrated starting position, so that the solenoid valve 1 closes again. This starting position is initially reached at time T2. At least by the set in motion mass of the anchor plate 5 there is an overstroke caused by the overstroke spring 6 partially compensated. Due to the effect of the solenoid valve spring 7 , the over-travel spring 6 and the kinetic energy of the anchor plate 5 creates an up and down movement of the anchor 4 and / or the anchor plate 5 , the so-called anchor bounce. This is in 2 initially visible between times T2 and T3. In the present case is under an anchor bouncing in particular also a movement of the anchor plate 5 be understood alone.

Because basically every movement of a component within the solenoid valve 1 A metering inaccuracy may result, also causes a movement of the anchor plate 5 alone, for example, by the resulting overstroke, a Zumessungenauigkeit. By means of the present invention, it is also possible to identify such a metering inaccuracy due to this particularly well, so that suitable countermeasures can be taken as described.

At the time T3, the controller again causes energization of the solenoid valve 1 , This causes a movement of the anchor again 4 towards the solenoid 8th so that the air gap 12 reduced again. In 2 It can be seen that the flank, which is the reduction of the air gap 12 represents, is not a straight-line movement, but has bumps. These bumps are due to the still existing anchor bounces. After opening the solenoid valve 1 is in the so-called holding current phase, which lasts until the time T4, the anchor bounce continues to be apparent. This causes an inaccuracy of the metered amount of fuel. By comparing the actual current profile between the times T3 and T4 with the desired current profile, which corresponds to the current profile between the times T0 and T1, it is thus possible to conclude that an armature bounce has occurred.

At the time T4, the control unit again causes the interruption of the current supply. At the time T5 is a renewed energization of the solenoid valve 1 caused by the controller. Also in the third energization phase thus formed between the times T5 and T6, the effect of the armature bounce through the wavy course of the armature lift is clearly visible. Once again, the occurrence of an armature bounce can be detected by comparing the actual current profile, now between the times T5 and T6, with the desired current profile, which corresponds to the current profile between the times T0 and T1.

After at the time T6, the energization of the solenoid valve 1 is interrupted again takes place in 2 no further energization of the solenoid valve 1 , Based on the date T7 in 2 Ankerhubverlaufs shown is clearly the anchor bounce recognizable.

In order to achieve a high metering accuracy, it is advantageous to energize the solenoid valve 1 only to be initiated when the anchor bounce has subsided or if the stroke of the bouncing anchor 4 does not exceed a given limit. It is also conceivable to energize the solenoid valve 1 then cause again when the frequency of the armature bounce exceeds or falls below a predetermined limit.

In 3 a current profile is shown with a pre-energization. At a time T10, the solenoid valve 1 subjected to a Vorvorromung V1. This is caused for example by the control unit. In the 3 shown Vorbestromung V1 initially increases to a value of about 1 A and then drops back to about 0.7 A. Between the times T10 and T11 no armature bouncing occurs. Thus, for example, the maximum current of the Vorvorromung V1, here about 1 A, are used as an actual current characteristic I_ist.

At a time T11, the actual energization or main energization of the solenoid valve begins 1 that has an opening of the solenoid valve 1 causes. The time T11 corresponds to the in 2 represented time T0.

At a time T12 ends according to the in 2 shown time T1, this first energization of the solenoid valve 1 and the current drops to zero at time T13. At this time, a Vorvorromung V2 is made again. This second Vorvorromung V2 ends at a time T14, in which a further Hauptbestromung is started. The Vorvorromung V2 can be initiated, for example, by the controller. In this case, for the second Vorstrromung V2 between the times T13 and T14 by the controller, the same voltage to the solenoid valve 1 as for the first pre-energization V1 between times T10 and T11.

How out 3 is apparent, that is actually through the solenoid valve 1 flowing current during the second pre-energization V2, however, higher than during the first pre-energization V1. This is due to the anchor bounce and the resulting induction of currents. By the movement of the anchor 4 the inductance of the solenoid changes 8th because the air gap 12 changes what a change in the magnetic field of the solenoid 8th entails, so that an induction current in the magnetic coil 8th is induced. In particular, during the second pre-energization V2, the maximum current I_act is higher than the maximum current I_set during the first pre-energization V1 and can therefore be used as a criterion for detecting the armature bounce.

A change in the inductance is further effected by the fact that the armature 4 partly in through the magnetic coil 8th formed ring enters, leaving the anchor 4 a kind of coil core with respect to the magnetic coil 8th forms. As a result, the magnetic field and thus the inductance of the magnetic coil changes 8th because the material of the anchor 4 has a different permeability than the otherwise located there medium, so for example fuel or air.

By means of a simple measurement of the current during a Vorbefromung V1, V2 through the solenoid valve 1 flows and a comparison of the measured current, such as the maximum current I_ist or a current waveform, with the originally intended for the Vorbestromung current, for example, the maximum current I_soll or a current waveform, can thus be easily determined the presence of an armature bounce.

In particular, it is possible to determine the duration of an anchor bounce. This, in turn, allows a solenoid valve 1 operate such that a Hauptbestromung of the solenoid valve takes place only when an anchor bounce is no longer present. This is during the energization, here the main current, a higher Zumessgenauigkeit reachable.

Claims (10)

Method for detecting an armature bounce in a solenoid valve ( 1 ), characterized in that the solenoid valve ( 1 At least one desired current characteristic (I_soll) is assigned, an actual current characteristic (I_ist) is detected, it is checked whether the actual current characteristic (I_ist) corresponds to the desired current characteristic (I_soll) and an armature bounce is concluded, if that Is current characteristic (I_ist) not only insignificantly deviates from the desired current characteristic (I_soll). Method according to claim 1, characterized in that that the desired current characteristic (I_soll) and the actual current characteristic (I_ist) with respect to a Pre-energization (V1, V2) can be determined. Method according to claim 1 or 2, characterized that the desired current characteristic (I_soll) and the actual current characteristic (I_ist) in terms of a Nachladestroms be determined. Method according to one of the preceding claims, characterized characterized in that the desired current characteristic (I_soll) by means of a Target current profile and / or the actual current characteristic (I_ist) by means of an actual current profile is described. Method according to one of the preceding claims, characterized characterized in that depending the actual electricity feature at least one feature of the anchor bounce is detected. Method according to claim 5, characterized in that that the feature is a lifting height of the bouncing anchor, a duration of the anchor bounce, or a frequency of the anchor bounce. Control device for controlling a solenoid valve tils ( 1 ), whereby the solenoid valve ( 1 ) an anchor ( 4 ), characterized in that the control device comprises means for performing a method according to one of claims 1 to 6. Control device according to claim 7, characterized in that the control device comprises means for actuating the solenoid valve ( 1 ) depending on the recognized feature of the anchor bounce. Computer program that is used in a computing device, in particular in a control device for controlling a solenoid valve ( 1 ), characterized in that the computer program for performing a method according to one of claims 1 to 8 is programmed when it runs on the control unit. Computer program according to claim 9, characterized that computer program is stored on a memory element, the storage element being a floppy disk, compact disk (CD), digital Versatile disk (DVD), and / or at least one at least one component assigned to the computing device Memory area is formed.