DE102011085277A1 - Method for operating switching valve of fuel conveying device of combustion engine mounted in motor car, involves changing amplitude and/or duration and/or timing of control until change of voltage falls below threshold value - Google Patents

Abstract

The method involves controlling the actuator device (9) temporarily such that a movable armature of the actuator device before reaching an end position is braked. The control for braking of the armature is determined so that change of applied voltage of the coil of electromagnetic actuator device in a time interval is determined so that the armature reached the end position. The amplitude and/or duration and/or timing of the control are changed until the change of voltage falls below the threshold value. An independent claim is included for computer program for operating switching valve.

Description

State of the art

The invention relates to a method according to the preamble of claim 1, and a method, a computer program and a control and / or regulating device according to the independent claims.

Quantity control valves, for example in a fuel delivery device of an internal combustion engine, are known from the market. Flow control valves are generally operated electromagnetically as switching valves with two switching positions and are often an integral part of a high-pressure pump of the fuel delivery device. The quantity control valve controls the amount of fuel pumped to a high-pressure accumulator ("rail"), from where fuel is directed to the injection valves of the internal combustion engine. An armature coupled to a valve body of the quantity control valve can be moved by magnetic force. The valve body - usually an inlet valve of the high pressure pump - can strike against a valve seat, or be lifted from the valve seat. As a result, a conveyed fuel quantity of the internal combustion engine and thus ultimately the pressure in the rail can be regulated.

Disclosure of the invention

The problem underlying the invention is solved by a method according to claim 1 and by a method, a computer program and a control and / or regulating device according to the independent claims. Advantageous developments are specified in subclaims. Features which are important for the invention can also be found in the following description and in the drawings, wherein the features, both alone and in different combinations, can be important for the invention, without being explicitly referred to again.

The invention has the advantage that a switching valve can switch controlled in particular when switching off an energization of an electromagnetic actuator by an anchor is braked before reaching an end position by means of a defined and variable for example over the operating time control. In this case, an operating noise of the switching valve can be significantly reduced over its entire life and independent of manufacturing tolerances, since the optimal deceleration can be achieved regardless of the operating time and manufacturing tolerances. The invention is particularly applicable to a quantity control valve of a fuel delivery device of an internal combustion engine or to a shift valve of a transmission control. Furthermore, the invention for switching valves or for quantity control valves applicable, which are "normally closed" or "normally open".

The invention relates to a method for operating a switching valve, which can be opened and / or closed by means of an electromagnetic actuator. When energized actuator, the switching valve can assume a first switching position and not energized actuator a second switching position. The latter is achieved for example by means of spring force and / or by a hydraulic or pneumatic pressure. In this case, the actuating device is at least temporarily controlled such that a movable armature of the actuating device is braked before reaching an end position. As a result, the impact energy when reaching the end position, which corresponds for example to a rest seat and / or a stroke stop of the armature or of a valve element, can be reduced. The method is particularly useful before or when reaching the non-energized second switching position, but it is applicable in a comparable manner before or when reaching the first switching position. Furthermore, if necessary, even the positioning accuracy of the switching valve can be increased with the method.

According to the invention, the control for braking the armature is determined by determining a change in a voltage applied to a coil of the electromagnetic actuator voltage in a time interval in which the armature reaches the end position. As long as a magnetic flux passing through the coil undergoes a change, a voltage is induced in the coil according to the law of induction. However, as soon as the armature strikes at the end position, its velocity is abruptly reduced to zero and a change in the magnetic flux caused by the armature movement stops abruptly as well. Accordingly, the voltage applied to the coil experiences a sudden change, wherein the proportion of the voltage induced due to the armature movement assumes the value zero. This process is inventively optimized by an amplitude and / or a duration of the control is gradually reduced until the change in the voltage falls below a threshold value. Preferably, the threshold value is dimensioned such that a required switching behavior on the one hand and a wear or a stop noise of the switching valve on the other hand are taken into account together. Alternatively or in addition to the reduction of the amplitude and / or duration and a timing of the control can be changed, which may also result in a modified braking effect. The method is particularly easy to use if there are already devices to electronically control or regulate the switching valve already during the energization of the coil - ie before reaching the first switching position (CVO, "controlled valve operation"). The aim is to achieve as soft as possible striking the anchor at the stop, which means that the anchor at the time of attack has the lowest possible residual velocity.

In addition, it is provided that, the control for braking the armature is determined occasionally or periodically after a certain period of operation, and that at least one of the determined control characterizing size is stored in a data memory. As a result, a possible over the operating life resulting wear of the switching valve is taken into account and thus an operating noise can be permanently reduced. The variable which characterizes the respectively determined drive is stored non-volatile and can thus be used for the further operation of the internal combustion engine. A renewed determination of the control after each start of the internal combustion engine is therefore generally not required.

It is particularly useful if the switching valve is a quantity control valve of a fuel delivery device of an internal combustion engine or a switching valve of an automatic transmission of a motor vehicle. The quantity control valve regulates the delivery of fuel into a high-pressure accumulator ("rail") of the internal combustion engine and thus also the fuel pressure. In particular, a quantity control valve is switched with a comparatively high frequency, so that an operating noise of the quantity control valve can be significantly reduced by means of the invention. In addition, the method can also be used for other types of switching valves, which have a first and a second switching position and are actuated electromagnetically.

The method is particularly accurate when the drive for braking the armature in an operating range of the engine at low speed, preferably idle speed is determined. In a range of low rotational speeds of the internal combustion engine, the hydraulic flow forces acting on the movable elements of the quantity control valve are comparatively small, and often it is also a quasi-stationary operating state which also facilitates the adaptation. Therefore, the process according to the invention "adaptation" of the control in this speed range can give particularly reliable values. The values determined in this way can be used during further operation of the internal combustion engine, in particular for the range of the idling speed. However, it is possible to apply these values also for speeds above the idling speed. The advantage would be that the adaptation would lead to no user-detectable noise emissions, since in this operating state the noise of the quantity control valve is drowned out by the noise of the internal combustion engine.

The method is further improved if the drive for braking the armature is determined as a function of a rotational speed of the internal combustion engine. The quantity control valve is generally switched as a function of the operating frequency of an associated high pressure pump, wherein the operating frequency of the high pressure pump in turn depends on the speed of the internal combustion engine. For example, the ascertained values of the activation as a function of the rotational speed are stored in a characteristic field of a control and / or regulating device. Thus, in operation also for speeds above the idle speed, the control of the quantity control valve can be made optimally.

Furthermore, the invention comprises a method for operating a switching valve, which can be opened and / or closed by means of an electromagnetic actuator, and which can assume a second switching position when energized actuator and a second switch position when not energized actuator, wherein according to the invention reaching a not more defined controllable operating range of the switching valve is detected by measuring the induction in a coil of the electromagnetic actuator. For example, the no longer defined controllable operating range mean that due to a particularly high switching frequency of the quantity control valve, an end position of the armature and / or a valve element can no longer be achieved. This can be recognized, for example, by the fact that a voltage induced in the coil after switching off the current supply and before switching on a subsequent energization no longer has a sudden change.

Furthermore, the invention provides a computer program which is programmed to carry out the method. Alternatively or additionally, individual, several or even all method steps can also be carried out by means of an electronic circuit. The computer program is preferably executable on a control and / or regulating device of the internal combustion engine.

The inventive method is particularly simple and inexpensive to set up when it is carried out by means of a control and / or regulating device, on which both a Computer program for carrying out the adaptation method for operating the quantity control valve as well as a computer program for carrying out an adaptation method for operating a fuel injection valve is executable. In this way, identical or at least similar algorithms can be used for both types of valves, whereby both computer programs can also share program parts and / or variables. For example, the fuel injection valve and the quantity control valve can be adapted in chronological succession. If the method is carried out at least partially by means of electronic circuits-for example in an ASIC (application-specific integrated circuit) or in an FPGA (freely programmable digital circuit) -these can possibly be used identically or even shared. Likewise, it is possible according to the invention to carry out the adaptation of the quantity control valve and the adaptation of the fuel injection valves in chronological succession, whereby the computer program (s) can or may be programmed particularly easily.

Hereinafter, exemplary embodiments of the invention will be explained with reference to the drawings. In the drawing show:

1 a simplified diagram of a fuel delivery device of an internal combustion engine;

2 a sectional view of a high pressure pump of the fuel delivery device together with a quantity control valve and an electromagnetic actuator;

3 a simplified timing diagram with a control of the electromagnetic actuator and an armature movement;

4 a flowchart for operating the quantity control valve; and

5 a simplified timing diagram with a speed of an anchor. The same reference numerals are used for functionally equivalent elements and sizes in all figures, even in different embodiments.

1 shows a fuel conveyor 1 an indicated only by their reference numeral internal combustion engine 2 in a simplistic representation. From a fuel tank 3 Fuel - such as gasoline or diesel fuel - via a suction line 4 , by means of a pre-feed pump 5 , via a low pressure line 7 , and about one of an electromagnetic actuator 9 ("Solenoid") actuatable quantity control valve 10 a (not further explained here) high-pressure pump 11 fed. Downstream is the high pressure pump 11 via a high pressure line 12 to a high-pressure accumulator 13 ("Common rail") connected. Other elements, such as high-pressure pump valves 11 , are in the 1 not drawn. The electromagnetic actuator 9 is controlled by a control and / or regulating device 16 controlled, on which a computer program 18 is executable. The control and / or regulating device 16 also includes a data store 19 ,

It is understood that the quantity control valve 10 also as a unit with the high-pressure pump 11 can be trained. For example, the quantity control valve 10 a forced openable inlet valve of the high pressure pump 11 be.

In addition, the control and / or regulating device 16 a second computer program 17 which is similar to how it is below for the flow control valve 10 will be described, injection valves of the internal combustion engine 2 adapt in an appropriate way and thus can operate optimized. However, this is not explained in detail here.

During operation of the fuel delivery device 1 promotes the pre-feed pump 5 Fuel from the fuel tank 3 in the low pressure line 7 , The quantity control valve controls 10 the one working space of the high pressure pump 11 supplied amount of fuel by an anchor 30 (please refer 2 ) of the electromagnetic actuator 9 is moved. The quantity control valve 10 - corresponding 2 the inlet valve of the high-pressure pump 11 - Can be closed or forcibly opened.

2 shows a partial sectional view (longitudinal section) of the high-pressure pump 11 the fuel conveyor 1 together with the quantity control valve 10 and the electromagnetic actuator 9 , The illustrated arrangement comprises a housing 20 in which in the upper part in the drawing the electromagnetic actuator 9 , in the middle area the quantity control valve 10 , and at the bottom of a pump room 22 together with a piston 24 the high pressure pump 11 are arranged.

The electromagnetic actuator 9 is in a valve housing 26 arranged, and includes a coil 28 , an anchor 30 , a pole core 32 , an anchor spring 34 , a retirement home 36 and a stroke stop 38 , The stroke stop 38 and in particular the retirement home 36 each also designate an "end position" of the anchor 30 , A concern of the anchor 30 at the stroke stop 38 corresponds to a first switching position and a concern of the anchor 30 at the retirement home 36 corresponds to a second Switch position of the quantity control valve 10 , The anchor 30 acted upon by means of a coupling element 40 a valve body 42 , In the drawing above the valve body 42 is an associated sealing seat 44 arranged. The seal seat 44 is part of a pot-shaped housing element 46 , which inter alia the valve body 42 and a valve spring 48 encloses. sealing seat 44 and valve body 42 form the inlet valve of the high-pressure pump 11 ,

Shown in the 2 the de-energized state of the electromagnetic actuator 9 , This is the anchor 30 by means of the anchor spring 34 in the drawing down against the retirement seat 36 pressed. About the coupling element 40 thereby becomes the valve body 42 against the force of the valve spring 48 applied, whereby the inlet valve or the quantity control valve 10 forcibly, ie independent of the pressure conditions between the pumping chamber 22 and the low pressure line 7 , opens. This creates a fluidic connection between the low-pressure line 7 and the pump room 22 produced, so that even with a delivery stroke of the piston 24 no fuel in the rail 13 is encouraged.

In the energized state of the electromagnetic actuator 9 becomes the anchor 30 from the pole core 32 magnetically attracted, causing the anchor 30 connected coupling element 40 is moved upward in the drawing. This can - with appropriate fluidic pressure conditions - the valve body 42 by the force of the valve spring 48 against the seal seat 44 are pressed, and the intake valve or the quantity control valve 10 thus close. This can be done, for example, when the piston 24 in the pump room 22 performs a working movement (in the drawing upwards) ("delivery stroke"), wherein fuel via an open check valve 50 in the high pressure line 12 can be promoted.

Opening or closing the quantity control valve 10 occurs depending on several sizes: First, depending on the anchor spring 34 and the valve spring 48 exercised forces. Second, depending on the low pressure line 7 and the pump room 22 prevailing fuel pressure. Third, depending on the power of the anchor 30 which is essentially from a current through the coil 28 flowing electricity 29 is determined. In particular, the electricity 29 - Again, also dependent on the respective fuel pressures - the time of opening or closing of the valve body 42 during a delivery stroke and thus substantially control the amount of fuel to be delivered.

3 shows two highly simplified timing diagrams for operating the quantity control valve 10 , In an upper timing diagram, one is to the coil 28 switched voltage 58 applied over a time t. For example, an amplitude of the voltage 58 set by means of a pulse width modulation (not shown). In a lower timing diagram is a movement 60 of the anchor 30 between the retirement home 36 and the stroke stop 38 applied over time t. The diagrams have a time scale that is equal to each other.

At a time t1 becomes a comparatively large voltage 58 to the coil 28 switched, whereby the electromagnetic actuator 9 so energized. This will be the anchor 30 from the retirement home 36 lifted off and in the direction of the stroke stop 38 moved by magnetic force. Subsequently, the anchor reaches 30 the stroke stop 38 and stays there until a time t2. At time t2, the voltage is 58 switched off and thus assumes approximately the value zero. Below is the anchor 30 by means of the force of the anchor spring 34 from the stroke stop 38 lifted and back towards the retirement home 36 accelerated.

At a time t3, the coil becomes 28 by means of tension 58 redirected. There is thus a control 62 for braking the anchor 30 , The polarity of the drive 62 is equal to the polarity of the voltage 58 between times t1 and t2, but the amplitude of the drive 62 comparatively small. This will increase the acceleration or speed of the anchor 30 reduced. At a time t4, the voltage becomes 58 or the control 62 switched off, so that subsequently at a time t5 the armature 30 at the retirement home 36 can strike. Here is the impact speed thanks to the previous control 62 comparatively low. An operating noise of the quantity control valve 10 is lowered by it.

In a time interval 64 from the time t4, in an environment of the time t5, the coil can be at the time 28 voltage applied 58 be determined. In particular, a by the movement of the anchor 30 induced voltage 58 be determined, which when striking the anchor 30 at the retirement home 36 a "sudden" change 84 (please refer 5 ) having. For example, an amplitude of the voltage 58 be changed by a value leaps and bounds. This change 84 can subsequently against a threshold 80 (please refer 4 ) and therefrom a measure of the velocity of the anchor 30 at the retirement home 36 be determined. The in the time interval 64 induced voltage 58 can in terms of the amplitude of the drive 62 be comparatively small and is in the 3 not explicitly shown.

The in the 3 diagrams shown are simplified by means of sectional straight lines. It is understood that the time course of the coil 28 applied voltage 58 due to the induction as well as due to possible measures for the deletion of the time t2 by the coil 28 flowing electricity 29 if necessary, may differ greatly from the representation. Likewise, the movement of the anchor 30 shown in simplified form.

4 shows a flowchart for the computer program 18 or part of the computer program 18 for operating a switching valve or the quantity control valve 10 , The following times refer to the presentation of the 3 , At a start block 66 begins the procedure shown. In a query block 68 the current time t is determined and checked whether a predefined waiting time has been exceeded since the last run of the procedure. The waiting time can be, for example, an operating period of the internal combustion engine 2 of one hundred hours. If the waiting time is not exceeded, then it becomes an end block 70 branched.

Otherwise it will be in a query block 72 checked if the internal combustion engine 2 currently in one operating area 73 an idle speed is operated. If this is not the case, then the end block 70 branched. Otherwise, wait until the energization of the coil 28 is switched off at the time t2. After that, in a block 74 waited for a predetermined period of time and then takes place at time t3 a pulse-like control 62 the coil 28 with an initially comparatively low - or even vanishing - electrical energy. At time t4, the control is 62 switched off again. In the time interval 64 - that is in the vicinity of the time t5 - is the at the coil 28 voltage applied 58 determined. In particular, the leaps and bounds change 84 the tension 58 in the time interval 64 determined (see also 5 ). This describes the time interval 64 only the measurement interval in which the erratic change 84 takes place or is expected. The sudden change 84 has a flank, which is generally much shorter than the time interval 64 , In a following block 76 be a current amplitude and duration of the drive 62 and a difference of the times t2 and t3 in the data memory 19 stored.

In a following query block 78 it will check if the change 84 the tension 58 a predefinable threshold 80 has fallen below. If so, it will become the end block 70 branched. Otherwise, the amplitude and / or the duration of the drive 62 increased by a difference value and / or the time t3 changed. After that, it will be the beginning of the query block 72 Branched back. There is thus a kind of "stepwise control" to minimize the operating noise of the switching valve or the quantity control valve 10 ,

After a successful run in the 4 The procedures shown are in the data store 19 stored at least one amplitude, a duration and the difference of the times t2 and t3, by means of which the control 62 the coil 28 such that the anchor 30 before hitting the retirement home 36 is optimally braked. With these in the data store 19 stored sizes can in the further operation of the quantity control valve 10 a striking noise of the anchor 30 be reduced and the quantity control valve 10 therefore quieter work. A repeat of the in the 4 shown part of the process can be done periodically or occasionally; compare to the "waiting time" described above. It is understood that in the 4 described procedure and / or thereby enabled optimized control 62 for braking the anchor 30 wholly or partly by an electronic circuit, for example by means of integrated circuits, can be performed.

If the change 84 the tension 58 in the time interval 64 is outside a predetermined range, it can be concluded that an operating range of the switching valve, which can no longer be defined, is reached. In this case, an entry in a fault memory of a diagnostic device of the internal combustion engine 2 done, and / or it can by means of the computer program 18 Measures are performed or initiated to end the undefined state as possible. Optionally, a "limit speed" can be determined, below which a safe operation of the switching valve can take place.

In addition, the in the 4 shown procedure at different speeds of the internal combustion engine 2 be performed. This allows the control 62 be optimized for speeds above the idle speed. Thus, during operation of the quantity control valve 10 a safe switching and minimized operating noise can be achieved in a comparatively large speed range. The determined optimal values of the amplitudes, the durations and the differences of the times t2 and t3 are stored in the data memory 19 stored, for example, as a table or as a map.

5 shows in addition to the 3 a simplified schematic time diagram with a speed 82 of the anchor 30 in the time interval 64 , After the end of the control 62 At time t4 the speed decreases 82 of the anchor 30 initially continue steadily. At time t5, the anchor beats 30 at the end position or the retirement seat 36 at, the speed 82 abruptly assumes the value zero.

Also after the end of the control 62 (please refer 3 ) may have a residual current 29 through the coil 28 flow and / or there may be portions of the electromagnetic actuator 9 or the anchor 30 still be magnetized. A the coil 28 passing magnetic flux depends in particular on the path of the armature 30 in the coil 28 from. Accordingly, the rate of change of the magnetic flux depends on the speed 82 of the anchor 30 from. According to the law of induction, it hangs in the coil 28 induced voltage 58 from the rate of change of the magnetic flux. Thus, the characterizes in the 5 shown speed 82 of the anchor 30 at the same time in the coil 28 induced voltage 58 ,

At time t5, the anchor beats 30 as described at the end position or at the retirement home 36 at. A change in speed 82 of the anchor 30 At time t5, this also characterizes a sudden change 84 the tension 58 , The change 84 becomes - as described above - with the threshold value 80 compared.

Claims (9)

Method for operating a switching valve, which is controlled by means of an electromagnetic actuator ( 9 ) can be opened and / or closed, and which when energized actuator ( 9 ) a first switching position and when not energized actuator ( 9 ) can assume a second switching position, wherein the actuating device ( 9 ) is at least temporarily controlled such that a movable armature ( 30 ) of the actuating device ( 9 ) before reaching an end position ( 36 ) is braked, characterized in that the control ( 62 ) for braking the armature ( 30 ) is determined by a change ( 84 ) one on a coil ( 28 ) of the electromagnetic actuator ( 9 ) applied voltage ( 58 ) in a time interval ( 64 ) is determined in which the anchor ( 30 ) the end position ( 36 ), wherein an amplitude and / or a duration and / or a time (t3) of the control ( 62 ) until the change ( 84 ) of tension ( 58 ) a threshold ( 80 ) falls below. Method according to Claim 1, characterized in that the control ( 62 ) for braking the armature ( 30 ) is determined occasionally or periodically after a certain period of operation has expired, and that at least one of the ascertained actuation ( 62 ) characterizing size in a data memory ( 19 ) is stored. Method according to at least one of the preceding claims, characterized in that the switching valve is a quantity control valve ( 10 ) a fuel delivery device ( 1 ) an internal combustion engine ( 2 ) or a switching valve of an automatic transmission of a motor vehicle. Method according to Claim 3, characterized in that the control ( 62 ) for braking the armature ( 30 ) in an operating area ( 73 ) of the internal combustion engine ( 2 ) is determined at low speed, preferably idle speed. Method according to claim 3 or 4, characterized in that the control ( 62 ) for braking the armature ( 30 ) in dependence on a rotational speed of the internal combustion engine ( 2 ) is determined. Method for operating a switching valve, which is controlled by means of an electromagnetic actuator ( 9 ) can be opened and / or closed, and which when energized actuator ( 9 ) a first switching position and when not energized actuator ( 9 ) can assume a second switching position, characterized in that reaching an undefined controllable operating range of the switching valve by measuring the induction in a coil ( 28 ) of the electromagnetic actuator ( 9 ) is detected. Computer program ( 18 ), characterized in that it is programmed to carry out a method according to one of the preceding claims. Control and / or regulating device ( 16 ) an internal combustion engine ( 2 ), characterized in that a computer program ( 18 ) is executable according to claim 7. Control and / or regulating device ( 16 ) according to claim 8, characterized in that both a computer program ( 18 ) according to claim 7 as well as a computer program ( 17 ) is executable for performing an adaptation method for operating a fuel injection valve.

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