EP1260694B1 - Method and device for increasing the voltage level of a high-dynamic inductive load - Google Patents

Description

Technical area

For applications on motor vehicles, the use of electromagnetically or electrohydraulically operated valves is in sight. With such valves, for example, the injection valves of an air-compressing internal combustion engine can be controlled. To achieve a high dynamic range, a high voltage is required for opening and partly also for closing. This high voltage has so far been generated by additionally required voltage transformers from smaller but existing voltage networks.

State of the art

DE 37 02 680 A1 relates to a method and a circuit for driving electromagnetic consumers. It is proposed a method for controlling electromagnetic loads with at least one magnetic coil, in particular magnetically actuated injection valves via at least one controllable switch. After switching off an electromagnetic consumer existing inductive energy of the current-carrying magnetic coil of the electromagnetic consumer is used for the switch-on of an electromagnetic consumer. In addition, a circuit is provided for carrying out the method, which is characterized in that at least one capacitor connected to an electromagnetic consumer is provided for temporarily storing the inductive energy present in the magnetic coil when the electromagnetic load is switched off.

DE OS 44 19 240 refers to a device for controlling an electromagnetic consumer. In this device, the energy released during shutdown is stored in a capacitor. This is the transition from a holding current transferred to the current zero energy released in a capacitor. The released during the transition from the starting current to the holding current electrical energy is lost in this device.

DE 195 39 071 (and US 5,936,827 ) relate to a device for controlling at least one electromagnetic consumer. The device comprises first switching means arranged between a first terminal of a supply voltage and a first terminal of at least one load, further second switching means arranged between a second terminal of an associated load and the second terminal of the power supply. In the transition from a first higher current value to a second lower current value, the released energy is stored in a storage means. US 5,909,353 has a circuit arrangement for the independent switching of several parallel-connected inductive switching units with inductive loads to the object. In particular, these inductive loads are the induction coils of powerful DC driven solenoid valves which require rapid shutdown to rapidly convert the energy stored in their magnetic field. Each inductive switching unit comprises an inductive load, a main switch which is connected to the positive pole of the DC voltage source and a blocking diode which is contacted at the connection point of the inductive load and the main switch and is connected in the reverse direction to the negative pole of the DC voltage source. The inductive switching units are connected in parallel to a freewheeling circuit which contains a freewheeling diode. The freewheeling circuit comprises a node, via which the inductive loads are connected by means of a freewheeling switch with the negative pole of the DC voltage source. The freewheeling circuit comprises between the positive pole of the DC voltage source and the junction of a switching group, which blocks the freewheeling circuit when switching off one or more inductive switching units until the voltage between the inductive loads and the switching group exceeds a threshold at the junction.

Presentation of the invention

With the proposed solution according to the invention, a voltage supply can be represented, with which the turn-on voltage of inductive actuators, for example, for switching on and off of valves for injection of fuel in internal combustion engines, with a mutual increase in voltage for switching the individual inductive actuators can be achieved. When switching off as a switch with short switching times Serving transistor, the construction of an overvoltage in the inductive actuator, which is passed via a diode in a capacitor. The voltage stored in the capacitor increases the operating voltage accordingly, so that a higher voltage is available for the following inductive actuator at the switching of this driving transistor. Due to the higher voltage, the valve shuts through faster.

The preferably used as a switch with short switching times transistor can be clocked in the on and off states, as long as it is ensured that the minimum waste stream at the inductive actuator is not exceeded or the Mindesteinschaltstrom remains exceeded. Between these current values, the transistor must be regulated accordingly.

If the overvoltage generated by switching off an inductive actuator in the capacitor is insufficient, then several switching inductive actuators can also be connected in parallel to the voltage boost to one or more capacitors. When switching off an inductive actuator without the transistor is conductive and occurrence of a voltage above the increased turn-on voltage of the actuators, this can be dissipated via a diode without the inductive actuator is damaged.

If the voltage above the generated turn-on voltage drops back to a voltage level at which the diode does not conduct, the residual energy stored in the capacitor is divided among the remaining series-connected inductive actuators and diodes.

In one embodiment variant of the solution proposed according to the invention, a removal of the cut-off energy of inductive actuators into a vehicle electrical system, for example of a motor vehicle, can take place via an analogue switch. When switched off as a switch with short switching times used transistor and not activated via the transistor inductive actuator, the cut-off of the inductive actuator can be fed back instead of a capacitor by activating the analog switch via a driver in the electrical system. As soon as the transistor is reactivated, the analogue switch is turned off so that the turn-off energy otherwise fed into the vehicle electrical system is passed when switching inductive actuators in capacitors, so that a voltage reserve for inductive actuators is available and activated more quickly, i. can be switched through.

When switching inductive actuators occurring voltage increases can be stored with the proposed solution according to the invention both in the capacitor and used for Durchschaltbeschleunigung and fed into the electrical system.

drawing

With reference to the drawing, the invention will be described below in more detail.

It shows:

FIG. 1

a block diagram of inductive actuators with to be controlled via a control unit transistors,

FIG. 2

a block diagram of another embodiment variant,

FIG. 3

a block diagram with a switching diode for feeding voltage spikes in the electrical system and

FIG. 4

a block diagram with an analog switch to dissipate the cut-off.

variants

FIG. 1 shows a block diagram with inductive actuators to be controlled via a control unit transistor.

In a vehicle power supply 1 having a voltage source 2, for example of a motor vehicle, a control unit 3 is accommodated, which, e.g. a microcontroller 4 comprises. Electromagnetic consumers in the form of a first actuator stage 5 of a second actuator stage 6 and a third actuator stage 7 can be designed, for example, the injection valves on an air-compressing internal combustion engine or as other actuators. The first actuator stage 5, the second actuator stage 6 and the third actuator stage 7 are each connected via input diodes 8 to the vehicle electrical system 1, whose supply voltage is provided by the voltage source 2. Each of the actuator stages 5, 6 and 7 is associated with an electric valve in the form of, for example, a current-carrying solenoid. These actuators can be, for example, fast-switching electromagnetic valves, actuators or even magnetic coils. Furthermore, each of the actuator stages 5, 6 and 7 comprises a switch with short switching times, for example, a transistor (field effect transistor), which is in communication with the control unit 3 before each of a control line 13 and 14 and 15 respectively. Furthermore, a diode 16 is accommodated in each of the actuator stages 5, 6 and 7 of the electromagnetic load, which is continuous only in one direction, consequently blocks in the other direction.

In the circuit variant according to FIG. 1 Each electromagnetic consumer in the form of an actuator stage 5, 6 or 7, a memory element for inductive energy such as a capacitor 17, 18 or 19 assigned.

With the in FIG. 1 reproduced circuit arrangement, a power supply can be provided which significantly increases the turn-on voltage of inductive actuators such as the electric actuators 9 (current-carrying magnetic coils) when switching on and off by mutual high voltage generation.

The electric actuator 9 of the first electromagnetic consumer in the form of an actuator stage 5 is supplied via the voltage source 2 in the electrical system 1 and via the input diode 8. About the preferably designed as a transistor fast switching switch the electric actuator 9 is connected to ground. When driving the transistor 10 via the associated control line 13 from the control unit 3, a current flow is generated by the electric actuator 9, for example, a magnetic coil. If the transistor 10 is switched off by the control unit 3 according to the timing set there via the control line 13, the inductively acting electric actuator 9 builds up an overvoltage which is conducted via the diode 16 into the memory 18 (for example a capacitor). Thus, a voltage greater than the voltage prevailing in the voltage source 2 of the vehicle electrical system 1 is available for the further actuator stage 6, ie the further electromagnetic consumer. When switching on the transistor 11 of the further electromagnetic consumer, ie, the second actuator 6 via the associated transistor 11, the electric actuator 9 can be switched through faster in the second actuator 6 due to the increased turn-on.

The acting as a fast-switching switch transistor can be clocked in the on and off states, as long as the minimum waste stream of a current as a current-carrying solenoid electric actuator is not reached or whose Mindesteinschaltstrom is exceeded. The timing can be calculated on the basis of the technical data of the electric actuator 9 and the voltage measured via the control unit 3. Based on these calculated values, the duty cycle can be adjusted and regulated accordingly.

FIG. 2 shows a block diagram of another embodiment of a circuit for increasing the turn-on voltage inductive actuators.

According to the block diagram in FIG FIG. 2 Instead of input diodes 8 to each of the electromagnetic load 5, 6 or 7 in the form of actuator stages switching elements 20, 21, 22 and 23 are provided, which are designed as Z-diodes whose Zener voltage determine the voltage overshoot to the supply voltage 2.

The electrical system 1 according to FIG. 2 contains analogous to the block diagram according to FIG. 1 a voltage source 2 and a control unit 3, which includes, for example, a microcontroller 4 among other things. From the control unit 3, drive lines 13, 14 and 15 extend to the switching elements 10, 11 and 12 of the individual electromagnetic consumers 5, 6 or 7, which are preferably in the form of transistors. Each of the electromagnetic loads 5, 6 or 7 in the form of actuator stages contains an electric actuator 9, a blocking diode 16 is connected in parallel. With appropriate control by the control unit 3, a current flow through the electric actuator 9 is caused by the transistor 10 in the electromagnetic load 5. When switching off the transistor 10 of the electrical load 5, the inductively acting electric actuator builds up an overvoltage, which is dissipated via the parallel-connected diode 16 and the electric actuator 10 of the further electromagnetic load 6 and the conducting transistor 11 of the electromagnetic load 6. Thus, an increased voltage is available for the electric actuator 9 in the further electromagnetic consumer 6, compared to the voltage generated by the voltage source 2 in the vehicle electrical system 1. When simultaneously or slightly premature switching of the preferably designed as a transistor switch 11 in further electromagnetic consumer 6 before switching off the transistor 10 in this upstream electromagnetic consumer 5, the electric actuator 9 in the second electromagnetic load 6 switches faster due to the increased voltage.

FIG. 3 is a block diagram removable with a connection of the electromagnetic consumers with each other.

The circuit arrangement according to FIG. 3 differs from the circuit arrangement according to FIG. 2 essentially in that each of the electric actuators 9 in the electromagnetic loads 5, 6 or 7, ie the 1.2. or 3 actuator are associated with two blocking diodes 16, which are each connected to different, the electric actuators 9 interconnecting parallel switching branches 24, 25 and 26 respectively. Analogous to the block diagram as shown in FIG FIG. 2 the on-board network 1 comprises a voltage source 2 and a control unit 3, in which a microcontroller 4 is accommodated. Each of the electromagnetic loads 5, 6 and 7 according to the block diagram in FIG. 3 Each of the transistors 10, 11 and 12 is connected via a drive line 13, 14 and 15 with the control unit 3 in connection and is controlled by this clocked. If the cut-off energy of a disconnecting electric actuator 9 is insufficient, several electric actuators 9 can also be used in parallel to the voltage boost. Thus, a voltage increase at the electric actuator 9 of the electromagnetic load 5 can be brought about by the fact that seen in the forward direction of the blocking diode 16, the voltage of the electric actuator 9 of the electromagnetic load 7 and the voltage of the electric actuator 9 is connected in the unnumbered electromagnetic consumer. For this purpose, the blocking diodes 16 are connected in parallel to the electric actuator 9 of the electromagnetic load 6 with the parallel switching branches 24 and 27 of the aforementioned electric actuators 9.

A switching voltage increase at the electric actuator 9 of the electromagnetic consumer 7, 6, i. the second actuator stage is carried out by applying the voltage to the electric actuator 9 of the electromagnetic load 5 via the parallel switching branch 24 and the forward direction of the diode 16 or by applying the voltage of the electric actuator 9 of the unnumbered electromagnetic consumer. Each of the parallel switching branches 24, 25 and 26 is provided with two voltage tap points, so that each two electric actuators 9 are assigned to increase the voltage.

In order to protect against excessively high turn-on voltages, the respective electrical actuators 9 in the switched-off state, without the correspondingly assigned transistor being conductive, are discharged via the switching elements 20, 21, 22 or 23 designed as Z-diodes, when the voltage exceeds the increased switch-on voltage the electric actuators 9 increases. Analogous to the representation according to the block diagram in FIG FIG. 1 If necessary, the transistors 10, 11 or 12 acting as switches can also be switched off in the meantime, as long as the respective minimum waste current of the electric actuators 9 is not undershot. Likewise, an electric actuator 9 for generating voltage can be switched on for a short time, as long as the minimum starting current is not exceeded.

The representation according to FIG. 4 is a block diagram with a switching element for removing the cut-off energy electrical actuators in the electrical system of a vehicle refer.

In the electrical system 1, a voltage source 2 is received, via which two parallel electromagnetic consumers 5 and 6 and a control unit 3 u.a. be supplied with a microcontroller 4 and two drivers 33 and 34 with electrical energy.

Each of the electromagnetic loads 5 and 6, in the present case a first actuator stage 5 and a second actuator stage 6, an analog switch 30 is assigned, which consists essentially of a blocking diode 31 and a transistor 32 connected in parallel to this. Everyone in FIG. 4 schematically illustrated electromagnetic load 5 or 6 comprises an electric actuator 9, which in each case an input diode 8 is connected upstream. Each of the electric actuators 9 is a blocking diode 16 connected in parallel. Analogous to the electromagnetic loads 5, 6 and 7 of the block diagrams according to the FIGS. 1, 2 and 3 also include the in FIG. 4 reproduced electromagnetic loads 5 and 6 each have a transistor 10 and 11, which act as fast switching switches and are controlled via the control lines 13 and 14 from the microcontroller 4 of the control unit 3 in a corresponding timing.

According to the block diagram in FIG FIG. 4 When switched off transistor 10 of the first electromagnetic consumer 5 and not activated electrical actuator 9 of the further electromagnetic consumer 6, the cut-off of the electric actuator 9 in the electromagnetic load 5, ie the 1st actuator stage by activation of the analog switch 30 of the electromagnetic load 5 via drivers 33 or 34 fed back into the electrical system 1 of a vehicle. Upon activation of the transistor 11 in the electromagnetic load 6, ie the second actuator stage of the analog switch 30 is turned off or not activated, so that the cut-off of the electric actuator 9 in the electromagnetic load 5 to increase the voltage at the electric actuator 9 of the electromagnetic load 6, ie the second actuator stage 6 can be used. This means that the electric actuator 9 can be switched through faster.

With the in the FIGS. 1 to 4 Exemplary reproduced block diagrams are characterized circuits with which a high dynamic range of inductive actuators can be achieved, for example, injectors of air-compressing internal combustion engines, which represent electromagnetic consumers in the sense of the above, highly dynamic to actuate and thus able to operate. Previously additionally required voltage transformers of smaller, existing on the vehicle, voltage networks can be omitted as well as additional to be used capacitors that are charged by clocked actuators. With the solution proposed according to the invention, a voltage supply can be realized which achieves a significant increase in the turn-on voltage of inductive actuators, such as, for example, current-carrying electrical magnet coils which are used as electrical actuators. The switching on and off of electromagnetic consumers can thus take place by means of mutual high-voltage generation, wherein the voltage increase for switching on an electric actuator 9 is previously used by the storage or diversion of the inductive energy during the shutdown of another electric actuator 9.

LIST OF REFERENCE NUMBERS

1

board network

2

voltage source

3

control unit

4

microcontroller

5

1st actuator stage (electromagnetic consumer)

6

2nd actuator stage (electromagnetic consumer)

7

3rd actuator stage (electromagnetic consumer)

8th

input diode

9

electrical actuator

10

transistor

11

transistor

12

transistor

13

drive line

14

drive line

15

drive line

16

blocking diode

17

capacitor

18

capacitor

19

capacitor

20

Zener diode

21

Zener diode

22

Zener diode

23

Zener diode

24

Paralleling branch

25

Paralleling branch

26

Paralleling branch

27

Paralleling branch

30

switching element

31

blocking diode

32

transistor

33

1. Driver

34

2nd driver

Claims (15)

1. Method for actuating electromagnetic loads (5, 6, 7) of an on-board vehicle power system (1), wherein the electromagnetic loads (5, 6, 7) comprise valves with actuators (9) for injecting fuel into an internal combustion engine, wherein the on-board vehicle power system (1) contains a voltage source (2) and a control device (3) which actuates the electromagnetic loads (5, 6, 7) via switches (10, 11, 12) assigned thereto, wherein the inductive energy which is present when one or more of the electromagnetic loads (5, 6, 7) is/are switched off, is used to raise the voltage when the other electromagnetic loads (5, 6, 7) are switched on, or is fed into the on-board vehicle power system (1) via switching elements (20, 21, 22, 23; 30, 33, 34) when a raised switch-on voltage of the electric actuators (9) is exceeded, characterized in that a plurality of electric actuators (9) are connected in parallel in order to increase the amount of inductive energy which is present when one or more of the electromagnetic loads (5, 6, 7) are switched off, wherein the electric actuators (9) are each connected to one another via blocking diodes (16) in such a way that the inductive overvoltage occurring when one of the electromagnetic loads (5, 6, 7) is switched off is reduced via at least one blocking diode (16) and at least one of the further switched-on electromagnetic loads (5, 6, 7).
2. Method according to Claim 1, characterized in that the switches (10, 11, 12) which are assigned to the electromagnetic loads (5, 6, 7) are clocked between the switched-on state and switched-off state by means of the control device (3).
3. Method according to Claim 2, characterized in that the control device (3) controls the clocking of the switches (10, 11, 12) in such a way that the minimum drop-out current is not undershot and the minimum switch-on current is not exceeded at the electric actuator (9).
4. Method according to Claim 2, characterized in that the switches (10, 11, 12) are switched off by means of the control device (3) for as long as the minimum drop-out current is not undershot at the electric actuator (9).
5. Method according to Claim 2, characterized in that the switches (10, 11, 12) are switched on by means of the control device (3) for as long as the minimum switch-on current is not exceeded at the electric actuator (9).
6. Method according to Claim 1, characterized in that, when the electric actuators (9) are switched off and the corresponding switches (10, 11, 12) are conductive and voltages are above a raised switched-on voltage of the electric actuator (9), said voltages are conducted away via switching elements (20, 21, 22, 23) which are embodied as Zener diodes.
7. Method according to Claim 6, characterized in that, when the opening voltage of the Zener diodes (20, 21, 22, 23) is undershot, the inductive residual energy in distributed among the electric actuators (9) of the electromagnetic loads (5, 6, 7).
8. Method according to Claim 1, characterized in that, when a switch (10) of a first electromagnetic load (5) is switched off and the electric actuator (9) of a further electromagnetic load (6) is not activated, the switch-off energy of the electric.actuator (9) of the first electromagnetic load (5) is fed back into the on-board vehicle power system (1) by the control device (3) actuating a switching element (30).
9. Method according to Claim 8, characterized in that, when a switch (11) of the further actuator stage (6) is activated, the switching element (30) is switched off, with the result that the inductive energy of the electric actuator (9) of the electromagnetic load (5) is used to raise the voltage at the electric actuator (9) of the further electromagnetic load (6).
10. Circuit for carrying out the method according to one or more of Claims 1 to 9, for actuating electromagnetic loads (5, 6, 7) of an on-board vehicle power system (1), wherein the electromagnetic loads (5, 6, 7) comprise valves with actuators (9) for injecting fuel into an internal combustion engine, wherein the on-board vehicle power system (1) contains a voltage source (2) and a control device (3) by means of which the electromagnetic loads (5, 6, 7) can be actuated via switches (10, 11, 12) assigned thereto, wherein the inductive energy which is present when one or more of the electromagnetic loads (5, 6, 7) is switched off can be used to raise the voltage when the other electromagnetic loads (5, 6, 7) are switched on, or can be fed into the on-board vehicle power system (1) via switching elements (20, 21, 22, 23; 30, 33, 34) when a raised switch-on voltage of the electric actuators (9) is exceeded, characterized in that a plurality of electric actuators (9) are connected in parallel in order to increase the amount of inductive energy which is present when one or more of the electromagnetic loads (5, 6, 7) is/are switched off, wherein the electric actuators (9) are each connected to one another via blocking diodes (16) in such a way that the inductive overvoltage occurring when one of the electromagnetic loads (5, 6, 7) is switched off can be reduced via at least one blocking diode (16) and at least one of the further switched-on electromagnetic loads (5, 6, 7).
11. Circuit according to Claim 10, characterized in that each electromagnetic load (5, 6, 7) is assigned a switch (10, 11, 12) which can be actuated by the control device (3) and an accumulator for electrical energy (17, 18, 19).
12. Circuit according to Claim 10, characterized in that each electromagnetic load (5, 6, 7) is respectively assigned a Zener diode as switching element (20, 21, 22, 23), the Zener voltage of which Zener diode defines the increase in the voltage with respect to the voltage supply (2).
13. Circuit according to Claim 10, characterized in that each electromagnetic load (5, 6) is assigned a switching element (30) which can be connected thereto using the on-board vehicle power system (1) and via which the switch-off energy of an electric actuator (9) can be fed back into the on-board vehicle power system (1).
14. Circuit according to Claim 13, characterized in that, when the switching element (30) is switched off, the switch-off of an electric actuator (9) is used to increase the voltage at a further electric actuator (9) of an electromagnetic load (5, 6).
15. Circuit according to one of Claims 10 to 14, characterized in that an electromagnetic load is designed to generate an overvoltage, and this overvoltage is made available at the correct time to other electromagnetic loads via the lines (24, 25, 26, 27) for high-dynamic actuation.

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