EP0812461B1 - Device for controlling at least one electromagnetic consumer - Google Patents

Abstract

A device for controlling at least one electromagnetic consumer has first switching means (115, 116) arranged between a first connection to a supply voltage and a first connection to at least one consumer (100, 101, 102, 103), and second switching means (120, 121, 122, 123) arranged between a second connection to an associated consumer (100, 101, 102, 103) and the second connection to the voltage supply. When passing from a first, higher current value (IA) to a second, lower current value (IH), the thus released energy is stored in storage means (145, 146).

Description

State of the art

The invention relates at least to a device for actuation of an electromagnetic consumer according to Preamble of claim 1.

A device for controlling an electromagnetic Consumer is, for example, from the unpublished DE-OS 44 13 240 known. With this device the energy released when switching off in a capacitor saved. The transition from a holding current energy released on current 0 into a capacitor reloaded.

The one when switching from the pull-in current to the holding current released energy is lost in this facility.

WO-A-89 03579 describes a circuit arrangement for Supply of an electromagnetic consumer with a Supply voltage and one in series to the consumer arranged driver circuit by an erase circuit can be bridged to switch off the consumer. in the The quenching circuit is an energy storage device in the form of a capacitor to absorb the energy stored in the consumer intended. The one released when the consumer is switched off Energy is always transferred to the capacitor. A Free running during a current control is with this device not feasible. If the switching device is defective the consumer is constantly energized.

US-A-4,862,866 shows a device around a capacitor to charge to an increased tension. For this, a additional coil energized. The one released when switching off Energy is used to charge the capacitor. This circuit is very expensive because in addition to the additional coil further switching means are required.

Object of the invention

The invention has for its object in a device to control an electromagnetic consumer to provide the simplest possible set-up, which accelerates the start-up process and the total energy consumption is minimized.

Advantages of the invention

The arrangement according to the invention with the features of the independent Claims has the advantage that the transition released from the pull-in current to the holding current Energy can be recovered. A particularly beneficial one Embodiment it is possible that with the same Power amplifier two consumers at the same time in different Be controlled in a way. This means that they overlap in time Injections possible.

drawing

The device according to the invention is based on the Embodiments illustrated in the drawing. FIG. 1 shows a first circuit arrangement of the invention Device, Figure 2 shows a second circuit arrangement and FIG. 3 different plots plotted over time Signals.

Description of the embodiments

The device according to the invention is preferred for internal combustion engines, especially with self-igniting internal combustion engines, used. There is the fuel metering controlled by electromagnetic valves. This electromagnetic Valves are referred to below as consumers designated. The invention is not limited to this application, it can be used wherever Fast switching electromagnetic consumers are required become.

When used in internal combustion engines, especially in Auto-ignition internal combustion engines set the opening and Closing time of the solenoid valve the start of injection or the injection end of fuel in the cylinder firmly.

In Figure 1 are the most important elements of the invention Facility shown. In the illustrated embodiment it is a four-cylinder internal combustion engine. Every consumer has an injection valve and a cylinder of the internal combustion engine for each injection valve assigned. With higher numbers of cylinders of the internal combustion engine are accordingly more valves, switching means and To provide diodes.

Four consumers are shown at 100, 101, 102 and 103. In each case a connection of the consumers 100 to 103 are over a switching means 115 and a diode 110 with a voltage supply 105 in connection.

The diode 110 is arranged so that it with its anode the positive pole and with its cathode with the switching means 115 communicates. The switching means 115 is concerned is preferably a field effect transistor.

In each case the second connection for consumers 100 to 103 stands above a second switching means 120, 121, 122 and 123 in connection with a resistance means 125. At the switching means 120 to 123 are also preferably around field effect transistors. The switching means 120 through 123 are used as the lowside switch and the switching means 115 referred to as highside switch. The second connection of the Resistance means 125 is connected to the second terminal Power supply in connection.

Each consumer 100 to 103 is a diode 130, 131, 132 and 133 assigned. The anode connection of the diodes is in each case with the connection point between consumer and Lowside switch in contact. The cathode connection is with a capacitor 145 and a further switching means 140 in connection. The second connection of the switching means 140 stands with the first connections of consumers 100 to 103 in contact. Switching means 140 is also involved preferably around a field effect transistor. This Switching means 140 is also referred to as a booster switch. The second connection of the capacitor 145 is also available the second connection of the supply voltage 105 in connection.

The highside switch 115 is operated by a control unit 160 with a control signal AH. The switching device 120 is sent by the control unit 160 with a control signal AL1, the switching means 121 with a drive signal AL2, the Switching means 122 with a control signal AL3, the switching means 123 with a control signal AL4 and the switching means 140 applied with a control signal AC.

Between the second connection of the voltage supply 105 and the connection point between the switching means 115 and the first connections of consumers 100 to 103 is one Diode 150 switched. Here the anode of the diode is included connected to the second connection of the voltage supply 105.

The resistor 125 can be used by the consumer flowing current can be determined.

With the arrangement shown, a current measurement is over the current measuring resistor 125 only possible if one of the Switching means 120 to 123 is closed. To the electricity too to be able to detect when the lowside switches are open the current measuring resistor is also arranged elsewhere become. For example, the second connection of the capacitor 145 with the connection point between the current measuring means 125 and the switching means 120 to 123 are connected. In this case, a current measurement is also in the blocked state Lowside switch possible. Furthermore, the current measuring means between the power supply and the highside switch or arranged between the highside switch and the consumers be.

A corresponding device is shown in FIG. where consumers 100 to 103 are divided into two groups are. The consumers 100 and 101 form a first one Group, and consumers 102 and 103 form a second Group of consumers. Consumers become the individual Groups assigned so that consumers who are under certain operating conditions are to be controlled simultaneously, be assigned to different groups.

Elements already described in FIG. 1 are shown in FIG corresponding reference numerals. For each group is A high-side switch 115 and 116 are provided. The Diode 111 corresponds to diode 110 of the first group. Corresponding the booster transistor 140 is also double to interpret. The booster transistor of the second group is designated 141. Accordingly, the capacitor 145 in the second group designated 146. Furthermore, there are two further control lines for the switching means 116 and 141 intended. The highside switch 115 of the first group becomes with the signal AH1 and the highside switch 116 of the second Group applied with AH2. The booster switch 140 of the first group is with the signal AC1 and Booster switch 141 of the second group comes with the signal AC2 applied. The resistor 125 is also corresponding double interpretation, this is in the second group with Designated 126.

In Figure 3a, the drive signal AC for the Booster transistor 140 and 141 applied. In Figure 3b is the control signal AH for the highside switches 115, 116 applied. Figure 3c shows the control signal AL one of the Lowside switch. In Figure 3d that is by the consumer flowing current I and in Figure 3e that applied to capacitor 145 Voltage UC plotted against time. Here is a metering cycle for a solenoid valve shown.

Different phases are distinguished in each metering cycle. In phase 0, before triggering the consumer the output stage is switched off. The control signals AC, AH and AL are at low potential. This means, that the highside switch 115, the lowside switch 120 to 123 and the booster switch 140 block the current flow. By no electricity flows to the consumers. The capacitor 145 is charged to its maximum voltage UC. This takes for example a value of approx. 80 volts, whereas the Voltage of the power supply assumes a value of approx. 12 V.

In the first phase at the beginning of the control, which as Booster mode is called the lowside switch controlled, which is assigned to the consumer, the fuel should measure. This means that from phase 1 the Signal AL assumes a high level. At the same time the line AC issued a high signal that the switch 140 controlled. The highside switch 115 is not activated, this continues to block. This control of Switching means causes the capacitor 145 through the Booster switch 140, the corresponding consumer, the Lowside switch assigned to consumers and the current measuring means 125 a current flows. In this phase, the Current I very much due to the high voltage at the consumer quickly. Phase 1 ends when the capacitor 145 applied voltage falls below a certain value U2.

In the second phase, which is referred to as starting current control the inrush current from the highside switch 115 taken over and the booster deactivated. In the second phase the control signal for the booster switch 140 is withdrawn, so that switch 140 locks. The control signals AH and AL for the highside switch 115 and the consumer assigned lowside switches are at high levels set so that these switches release the current flow. Consequently a current flows from the voltage supply 105 via the Diode 110, the highside switch 115, the consumer, the corresponding low-side switch, the current measuring resistor 125 back to voltage source 105. By touching the high-side switch can the current by means of the current measuring resistor 125 is recorded to a predeterminable value for the starting current IA can be regulated. That is, when reached of the target current IA for the starting current is the Highside switch 115 controlled so that it blocks. When falling short another threshold is released again.

When the highside switch 115 is blocked, a freewheeling circuit acts. The current flows from the consumer through the Lowside switch, resistor 125 and the freewheeling diode 150.

The second phase ends when the control unit 160 does so Is recognized at the end of the tightening phase. This can e.g. the case be when a switching time detection recognizes that the Solenoid valve armature has reached its new end position. Recognizes the switching point detection is not specified within a Time for the solenoid valve armature to reach its new end position error is recognized.

In the third phase, also known as the first quick erase the control signal for the corresponding Lowside switch withdrawn. This causes a Electricity from the respective consumer through the consumer associated diode 130 to 133 in capacitor 145 flows and the energy stored in the consumer in the Capacitor 145 is charged. The highside switch 115 is controlled in the illustrated embodiment so that it stays closed. In this phase the sinks Current from the starting current IA to the holding current IH. At the same time the voltage across capacitor 145 rises, to a value U3, but which is significantly below the value U1 lies. The third phase ends when the setpoint IH for the holding current is reached. The transition from the pull-in current IA on the holding current IH is released energy stored in the capacitor. It is particularly advantageous here that the transition from the pull-in current to the holding current done quickly due to the quick deletion.

The third phase is followed by the fourth phase, the is also referred to as holding current control. Corresponding as in the second phase, the control signal remains for the Lowside switch at its high level, that is Lowside switches assigned to consumers remain closed. By opening and closing the high-side switch 115 the current that flows through the consumer to the setpoint adjusted for the holding current. When locked Highside switch 115 acts as a freewheeling circuit. The current flows from the consumer through the lowside switch, the resistor 125 and the free-wheeling diode 150. Phase 4 has ended, when the injection process is completed.

In the subsequent fifth phase, which is also called the second Quick Erase and Quick Erase Verification the corresponding low-side switch is switched off and the highside switch 115 is turned on. In this Phase falls the current that flows through the consumer, also quickly decreases to zero. At the same time increases the voltage U applied to the capacitor 145 by one smaller value than in the third phase.

In the 3 and 5 phase the setpoint for the current I goes from a high to a low value. In these phases is the one assigned to the consumer Low-side switch controlled in such a way that the current flow locks. The energy released is transferred to the capacitor 145, 146 reloaded. One takes place in these phases Quick delete. This causes the current to flow quickly new setpoint reached.

Current control takes place in phases two and four Starting the high-side switch. When locked Highside switch, the free-wheeling diode 150 is active. In these Phases, the current drops slowly. This leads to a lower one Switching frequency.

In the sixth phase, the power amplifier is inactive, that is, there is no fuel metering. This means the control signal AC for the booster switch 140, the control signal AH for the highside switch and the control signal AL for the lowside switches all assume low levels and lock all switches. The electricity generated by the consumer flows, remains at 0 and the voltage across the capacitor 145 remains at its value.

In the seventh phase after the control, which is also called Is designated, the highside switch 115 by the control signal AH back to its conductive state brought. By closing a lowside switch initialized a current flow in one of the consumers. Of the Current flows, for example, via the diode 110, the switch 115, the consumer 100, the switching means 120 and that Current measuring means 125 back into the voltage source. When reached a setpoint for the current, which is selected so that the solenoid valve does not respond yet, the Lowside switch controlled so that it opens. this causes again a quick erase for the current path consisting of the consumer, one of the diodes 130 to 133 and the capacitor 145. As a result, the one present at capacitor 145 rises Tension. As soon as the current returns to zero reached, the lowside switch 120 is activated again. This process is repeated until the voltage on Capacitor 145 gradually reaches the value U1 again.

This is followed by phase 8, in which all control signals withdrawn and all switches in their locked state to be brought. This phase corresponds to phase 0.

It is envisaged that only one cylinder per metering cycle Has injection interval, so occur in a device no difficulties according to FIG. On the other hand, that a pre-injection before the main injection or a post-injection after the actual one Main injection takes place, the case can occur, that to control the solenoid valves of two cylinders simultaneously are. In particular, the main injection and the pre-injection of the following cylinder or the post-injection and the pre-injection of the following cylinder can overlap in time. This leads to a Circuit arrangement according to Figure 1 that the Lowside switch can be selected using two consumers of the high-side switch 115 but only a common one Current regulation is possible. With this arrangement two Valves are not controlled differently at the same time become. For example, it is not possible for one Solenoid valve the current on the holding current and the other Solenoid valve to regulate the starting current. Furthermore, the Capacitor 145 are driven before the next valve can be. If the switch-off points and the switch-on point two valves in quick succession, it is not possible to charge the capacitor 145.

Such control, in which two solenoid valves simultaneously are powered differently or that the capacitor 145 is loaded with a device possible according to Figure 2. With this arrangement, the consumers divided into two groups. Every group of consumers is a highside switch 115, 116, a Booster switch 140, 141, a measuring resistor 125, 126 and a capacitor 145, 146 is assigned. One group of each Consumers can use the respective highside switch 115 or 116 can be selected. According to the invention, that each different consumer groups assigned to the cylinders in which fuel is metered in succession.

The device according to the invention was based on the example of a Internal combustion engine shown with four cylinders. The method is also on internal combustion engines with others Number of cylinders transferable. There is a corresponding number for this of consumers, switching devices and other elements to provide. It can also be provided that the consumer is divided into a larger number of groups. This is particularly useful with higher numbers of cylinders.

In the embodiment described so far, the Current control phase a transition from a high current level to lower current level, with part of the stored electrical energy is used to partially remove the capacitor charge. The capacitor is charged further on Actuation end when the load current is quickly extinguished. Enough then the capacitor is charged for switching on again not yet off, is switched on and off periodically Load current (night clocking) between two injection processes and Another electrical storage Voltage increase reached.

High engine speeds mean shorter periods of time can be used to increase the voltage by means of night clocking can. At high speeds, the step up is in time not possible between two injections, so the Capacitor not charged to the required voltage can be. According to the invention, therefore, another Embodiment suggested that the voltage step-up is already carried out during the current control and the Capacitor completely again during activation is charged. This allows night clocking in the Control gap is eliminated. Furthermore, the risk is reduced that there is an undesirable injection because the Consumer not energized between the two injection processes becomes.

In FIG. 4, as in FIG. 3, the control signals are AC for the booster transistor 41, the drive signal in Figure 4b AH for the high-side switch, the control signal AL in FIG. 4c a low-side switch, a control signal AS in FIG. 4d takes the state of charge of the capacitor into account, in FIG current I flowing through the consumer and in FIG. 4f Capacitor falling voltage U plotted over time.

Corresponding to the control method according to FIG. 3 different phases. In a phase 0 that before de Control of the consumer is the final stage switched off. The control signals AC, AH, AL and the signal AS are at low potential. This means that the High-side switches, 115 the low-side switches 120 - 123 and the Booster switch 140 block the flow of current. By consumers no electricity flows. The capacitor 145 is at its maximum Voltage U10 charged. This takes a value of approx. 80 volts on, whereas the voltage supply values of approx. 12 volts assumes.

The first phase at the start of activation corresponds to the first Phase of the procedure according to FIG. 3. During phase 1 the signal AS rises to its high level. This indicates that the voltage drop across the capacitor is less than one predefined threshold value US.

In the 2nd phase, which is also called pull-in current control the inrush current from the high-side switch 115 taken over and the booster deactivated. This means that in the second phase, the control signal AT for the booster switch 140 is withdrawn so that the switch 140 locks. The Control signals AH and AL for the high-side switch 115 and the Low-side switches assigned to consumers take a high one Level on so that these switches enable current flow. Consequently a current flows from the voltage supply 105 via the diode 110, the high-side switch 115, the consumer, the corresponding low-side switch, the current measuring resistor 125 back to voltage source 105.

In contrast to phase 2 according to FIG. 3, contacting the Lowside switch the current, which by means of the Current measuring resistor 125 is detected to a predetermined value regulated for the pull-in current IA. That means when the The target current IA for the pull-in current is the low-side switch 120 controlled to 125 so that it locks. When falling below one another threshold, it is released again. This has to Consequence that with open low side switch 120 to 125 on Electricity from the respective consumer through the consumer associated diode 130 to 133 flows in the capacitor 145 and the energy stored in the consumer in the capacitor 145 is reloaded. At the same time, the voltage U rises Capacitor 145 is present.

The second phase ends when the control unit 160 ends the Recognizes the tightening phase. This can e.g. to be the case if one Switching point detection recognizes that the solenoid valve armature has reached its new end position.

In the third phase, which is also called the first quick delete is referred to, is corresponding to the third phase according to the first embodiment, the control signal for the corresponding Low side switch withdrawn. This causes a current from the respective consumer through the to the consumer associated diode 130-133 flows into capacitor 145. The in Energy stored in the consumer is transferred to the capacitor 145 reloaded. In this phase, the current drops from the pull-in current IA on the holding current IH. At the same time the voltage U rises, which is present at capacitor 145. The third phase is over when the setpoint for the holding current is reached. The at Transition from the pull-in current to the holding current is stored in the capacitor.

The fourth phase is followed by the fourth phase, which too is referred to as holding current control. As in the The second phase remains the control signal for the High-side switch at its high level, d. H. of the The high-side switch remains closed. When opening and closing of the low-side switch is the current flowing through the consumer flows to the setpoint for the holding current. At locked low side switch, the current flows from the respective Consumer through the diode 130-133 assigned to the consumer into the capacitor 145. This will result in the consumer stored energy transferred to the capacitor.

As soon as the voltage drop across the capacitor U a has reached the predetermined threshold value US, the signal AS changes to low potential. The first part 4a is thus the fourth phase ended. From this point on, the Current control no longer using the low-side switch, but instead using the high-side switch. That means the lowside switch is constantly in his managerial position and that High-side switch switches between its locked and its open position. With highside switch 115 locked acts as a free wheel. The current flows through the consumer the low side switch, resistor 125 and the free wheeling diode 150. The fourth phase is finished when the injection process is completed.

The subsequent fifth phase corresponds to the fifth phase the procedure according to FIG. 3. Phases six and seven, 3 are not in this type of control required.

As long as the signal AS is at its high level, i.e. the Voltage on the capacitor does not yet meet the specified setpoint US has reached, the output stage arrangement works as a current regulating Boost converter. The high-side switch is in this operating state switched through continuously. The current regulation takes place through the lowside switch assigned to the individual consumer. The periodically on and for current control is turned off.

The voltage U falling across capacitor 145 has one predetermined value US is reached in another Operating mode switched. In this operating mode no further charging of the capacitor. The current regulation takes place correspondingly as in the exemplary embodiment in FIG. 3 using the high-side switch.

The threshold value US for the capacitor voltage is preferred chosen so that the voltage at the end of phase 4a together with the voltage rise in the fifth phase a voltage value results, which is necessary for fast switching on. In the Phase 4a works the circuit arrangement as a step-up converter. The current control takes place in phase 4b by means of the high-side switch.

Claims (8)

1. Device for driving at least one electromagnetic load, in particular a solenoid valve for controlling the metering of fuel into an internal combustion engine, having a first switching means (115, 116), which is arranged between a first terminal of a supply voltage and a first terminal of at least one load (100, 101, 102, 103), having second switching means (120, 121, 122, 123), which are arranged between a second terminal of an associated load (100, 101, 102, 103) and the second terminal of the voltage supply, characterized in that means are provided which drive the second switching means (120, 121, 122, 123) in such a way that at least the energy which is released during the transition from a pull-in current value (IA) to a holding current value (IH) can be stored in a storage means (145, 146), and in that means are provided which drive the first switching means (115, 116) in such a way that, in a phase during which the current can be regulated to a set point, a free-wheeling diode (150, 151), which is connected between the first terminal of the load and the second terminal of the voltage supply, is acting.
2. Device according to Claim 1, characterized in that, in a first phase of the driving, the first terminal of the load can be connected to the storage means (145, 146) by means of a third switching means (140, 141).
3. Device according to Claim 1 or 2, characterized in that the energy which is released when the second switching means is opened can be stored in the storage means.
4. Device according to one of the preceding claims, characterized in that the energy which is released during transition from the holding current value (IA) to the value zero can be stored in the storage means (145).
5. Device according to one of Claims 1 to 4, characterized in that, in a phase in which the current can be regulated to a set point, the energy which is released can be stored in the storage means (145).
6. Device according to one of the preceding claims, characterized in that, in a phase which follows the driving, the second switching means are briefly driven in such a way that the load does not react, and in that the energy which is released when the second switching means is opened can be stored in the storage means.
7. Device according to one of the preceding claims, characterized in that the storage means is connected in parallel with the second switching means.
8. Device according to one of the preceding claims, characterized in that the loads can be divided up into at least two groups, to which in each case a first switching means (115, 116), a third switching means (140, 141) and/or a storage means (145, 146) are assigned.

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