JPH10205379A - Method and device for controlling electromagnetic load - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an accurate fuel adjusted amount by charging a charging means before first fuel injection after the state of no fuel injection if an electric charge charged in the charging means is charged again at the time of starting load control in the control method of a fuel injection control solenoid valve as an electromagnetic load. SOLUTION: For controlling loads (solenoid valves) 100 to 300 disposed in fuel injection valves provided for respective cylinders in a 4-cylinder engine, first low side switches 120 to 124 are controlled during a booster operation and currents are increased at a high speed. Then, during starting current adjustment, a switch-ON current is received by a high-side switch 115 and, when the objective current of the starting current is reached, the switch 115 is cut off and the current is supplied from the load through a free wheel diode 150. Then, in the period of high-speed elimination, corresponding low side switches 120 to 133 are cut off, currents are supplied through the diodes 130 to 133 of the respective loads to a capacitor 145 and then energy is charged again in the capacitor 145.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling an electromagnetic load, for example, an electromagnetic valve for controlling fuel injection of an internal combustion engine, wherein electric charges charged in a charging means are charged at the start of control of the load. How to be fixed.

[0002]

2. Description of the Related Art A device for controlling electromagnetic loads is known from DE-OS 4 413 240.
Here, a device for charging a booster capacitor with energy released when the switch is turned off is disclosed.
At the start of the immediately next control, the charged energy is recharged in the load.

Further, during the recharging time after the original control of the valve,
Devices are known which charge an additional charge in a capacitor by short-time switching on and off of current. This process is usually called recharging or recharging. This recharging needs to be as short as possible. This is because the usable time is, for example, in the case of a large rotation speed,
This is because it can be very short.

After switching on the control with the aid of an ignition switch, the capacitor is generally not charged. If the internal combustion engine has been in operation for a relatively long time without fuel injection, for example in engine braking, the capacitor is generally discharged as well. During subsequent control, the valve may not open or may open with a delay.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a control device for an electromagnetic load which achieves a fast and accurate switching process of the load even at the first control after no fuel injection. .

[0006]

According to the present invention, this object is achieved by charging the charging means after no fuel is injected and before the first fuel injection.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The apparatus according to the present invention will be described below with reference to the illustrated embodiments.

The device according to the invention is preferably used in internal combustion engines, in particular in self-igniting internal combustion engines. There, solenoid valves are used for fuel metering control. This solenoid valve is hereinafter referred to as a load. The present invention is not limited to this application and can be used anywhere a fast switching electromagnetic load is required.

In applications in internal combustion engines, in particular self-igniting internal combustion engines, the opening time of the solenoid valve is fixed at the start of the injection of fuel into the cylinder and the closing time is the injection of fuel into the cylinder. Fixed at end time.

FIG. 1 shows the main elements of the device according to the invention. The illustrated embodiment is a four cylinder internal combustion engine. At this time, a fuel injection valve is assigned to each load, and a cylinder of the internal combustion engine is assigned to each fuel injection valve. If the internal combustion engine has a relatively high number of cylinders, a correspondingly large number of valves, switching means and diodes are provided.

At 100, 101, 102 and 103, four loads are shown. The first terminals of the loads 100 to 103 are connected to the voltage source 105 via the switching means 115 and the diode 110, respectively.

The diode 110 has an anode connected to the positive pole and a cathode connected to the switching means 115. The switching means 115 is advantageously a field effect transistor.

Each of the second terminals of the loads 100 to 103 is connected to one second switching means 120,
It is connected to the resistance means 125 via 121, 122, 123. The switching means 120 to 123 are likewise advantageously field effect transistors. Switching means 120-123 are shown as low side switches, and switching means 115 is shown as high side switches. The second terminal of the resistance means 125 is connected to the second terminal of the voltage source.

Each of the loads 100 to 103 has a diode 1
30, 131, 132, and 133 are assigned. The anode terminals of the diodes are each contact-connected to a connection point between the load and the low-side switch. The cathode terminal is connected to the capacitor 145 and another switching means 140. The second terminal of the switching means 140 is connected in contact with the first terminals of the loads 100 to 103. This switching means 140 is likewise advantageously a field effect transistor. This switching means 140 is also called a booster switch. The second terminal of the capacitor 145 is also connected to the supply voltage 105
Are connected to the second terminal.

The control unit 160 supplies a control signal AH to the high side switch 115. Switching means 120 is supplied with control signal AL1 from control unit 160, switching means 121 is supplied with control signal AL2, and switching means 122 is supplied with control signal AL3.
Is supplied, and the switching means 123 outputs the control signal AL.
4 is supplied, and the switching means 140 outputs the control signal A
C is supplied.

A diode 150 is connected between a second terminal of the voltage source 105 and a connection point between the switching means 115 and the first terminals of the loads 100 to 103. At this time, the anode of the diode is connected to the second terminal of the voltage source 105.

By this control, in particular, the rotation speed sensor 18
A signal N of 0, a sensor 19 indicating the accelerator pedal position FP
5 and the voltage 190 applied to the terminal 50 are processed. When the starter is operated, the terminal 50
A voltage is applied. The voltage at terminal 50 indicates the operating state of the starter or the imminent starting state of the internal combustion engine.

Using the resistor 125, the current flowing through the load can be detected.

According to the illustrated device, the current measuring resistor 125
Measuring the current through the switching means 120
This is possible only when one of the １２３-123 is closed. Even when the low-side switch is open, a current measuring resistor may be provided at another location so that the current can be detected. For example, the capacitor 145
Can be connected to a connection point between the current measuring means 125 and the switching means 120-123. In this case, the current can be measured when the low-side switch is shut off. Further, the current measuring means may be provided between the voltage source and the high-side switch or between the high-side switch and the load.

FIG. 2A shows a booster transistor 14.
A control current AC for zero is described. In FIG. 2b,
The control signal AH for the high side switch 115 is described. FIG. 2c shows one control signal AL of the low-side switch. FIG. 2d shows the current I flowing through the load over time, and FIG.
The voltage UC applied to the capacitor 145 is shown over time. In this case, the control corresponding to the measuring cycle is shown without preliminary fuel injection for the solenoid valve.

In each measurement cycle, different phases are distinguished. In phase 0, the final stage is shut off before the control of the load. The control signals AC, AH and AL are at a low potential. That is, the high-side switch 115, the low-side switches 120 to 123, and the booster switch 140
Cuts off the current. No current flows through the load. Capacitor 145 is charged to its maximum voltage UC. This amounts to, for example, a value of about 80 volts, whereas
The voltage of the voltage source amounts to about 12 volts.

In the first phase at the start of the control, called the booster operating period, the low-side switch assigned to the load whose fuel is to be metered is controlled. That is, from the phase 1, the signal AL takes a high level. At the same time, a high signal is sent out on the line AC, and the switch 140 is controlled to be conductive by this signal. The high-side switch 115 is not controlled, and the switch continues to shut off further. The control of the switching means is effected by means of the capacitor 145 such that a current flows through the booster switch 140, a corresponding load, a low-side switch corresponding to this load and the current measuring means 125. In this phase, the current I rises very fast due to the high voltage of the load. This phase 1 consists of capacitor 1
The process ends when the voltage applied to 45 falls below a predetermined value U2.

In the second phase, also called the starting current adjustment period, the switch-on current is
15 and the booster is not activated. Second
In this phase, the control signal for the booster switch 140 is cancelled, and this switch 140 is therefore turned off. The control signals AH and AL for the high-side switch 115 and the low-side switch assigned to the load are set to a high level, so that this switch releases the current. Therefore, current flows from the voltage source 105 to the diode 11
0, high side switch 115, load, corresponding low side switch, voltage source 105 via current measuring resistor 125
Return to By high-side switch clock control,
The current detected using the current measuring resistor 125 is adjusted to a preset value for the starting current IA.
That is, when the starting current reaches the target current, the high-side switch 115 is controlled so that the switch is turned off. When another limit value is exceeded, the switch is released again.

When the high-side switch 115 is turned off, the freewheel circuit operates. Current flows from the load through the low side switch, resistor 125 and freewheel diode 150.

The second phase ends when the control unit 160 sends an end of the starting phase. This is the case, for example, when the switching time point detector detects that the armature of the solenoid valve has reached its new terminal position. If the switching time point detector does not detect within a predetermined time that the armature of the solenoid valve has reached its new end position, an error is detected.

In the third phase, also called the first fast erase period, the corresponding low-side switch is canceled. As a result, current flows from each load to the capacitor 145 through the diodes 130 to 133 assigned to the load, and the energy charged in the load is recharged to the capacitor 145. At that time, the high-side switch 115 is controlled so that the switch is kept closed in the illustrated embodiment. In this phase, the current drops from the starting current IA to the holding current IH. At the same time, the voltage applied to the capacitor 145 rises to the value U3, which is clearly below the value U1. The third phase ends when the target value IH for the holding current has been reached. The energy released when shifting from the starting current IA to the holding current IH is charged in the capacitor. In this case, it is particularly advantageous that the transition from the starting current to the holding current takes place at a high speed on the basis of a fast erase.

The third phase is followed by a fourth phase, also called a holding current adjustment period. Corresponding to the case of the second phase, the control signal for the low-side switch remains at its high level, ie the low-side switch assigned to the load remains closed. By opening and closing the high-side switch 115, the current flowing through the load is adjusted to the target value of the holding current. In the case of the interrupted high-side switch 115, the freewheel circuit operates. Current flows from the load through the low-side switch, the resistor 125 and the freewheeling diode 150. Phase 4 ends when the fuel injection process is closed.

In the subsequent fifth phase (also referred to as a second high-speed erase period), the corresponding low-side switch is closed, and the high-side switch 115 is turned on. Within this phase, the current flowing through the load is
Similarly, the value quickly drops to zero. At the same time, the voltage U applied to the capacitor 145 rises by a smaller value than in the third phase.

In the third and fifth phases, the target value of the current I shifts from a high value to a low value. In this phase, each low-side switch assigned to the load
It is controlled to cut off the current. In this phase,
High-speed erasure is performed. This causes the current to reach its new target value.

In phases 2 and 4, the current adjustment is performed by clock control of the high-side switch. In the case of an interrupted high-side switch, the freewheel diode 150 is activated. In this phase, the current decreases slowly. This results in a relatively small switching frequency.

In the sixth phase, the final stage does not operate, that is, no fuel metering is performed. That is, the control signal for the booster switch 140, the control signal AH for the high-side switch, and the control signal AL for the low-side switch are all at a low level, and all the switches are shut off. The current through the load remains at zero and the capacitor 145
Voltage keeps its value.

In the seventh phase after this control (also called a post-clock control period), the high-side switch 11
5 is rendered conductive again by the control signal AH. Closing the low-side switch initializes the current through one of the loads. This current returns to the voltage source through, for example, the diode 100, the switching means 120, and the current measuring means 125. The low-side switch is controlled to open when the target value of the current selected so that the solenoid valve still does not respond is reached.
As a result, the current path including the load, one of the diodes 130 to 133, and the capacitor 145 is erased again at a high speed. Thereby, the voltage applied to capacitor 145 increases.

As soon as the current falls below a predetermined value, the low-side switch 120 is activated again. This process is
This is repeated until the voltage of the capacitor 145 gradually reaches U1 again. This process is called recharging.

Subsequently, in phase 8, all control signals are reset and all switches are turned off. This phase corresponds to phase 0.

After the state of the internal combustion engine, in which no fuel injection takes place, the capacitor 145 is discharged during the first control of the load. In this case, the advantage of the capacitor cannot be used in the first control. In particular, the switching process is not accelerated and the fuel injection is not determined. Furthermore, when starting the internal combustion engine, the available voltage drops below normal values.

In order to solve this problem, it has been proposed to charge the charging means after a state in which fuel injection is not performed and before a new first fuel injection. With the evaluation of the appropriate signal, the imminent fuel injection is detected and the charging process of the capacitor is started.

Such a state where fuel injection is not performed is a stop state of the internal combustion engine. The charging process is started when a signal indicating an imminent starting process has occurred.
As a signal indicating the imminent start-up process, for example, a speed signal, the voltage of the terminal 50 or the voltage of the terminal 15 can be used.

Another state in which fuel injection is not performed is an engine braking state. The charging means is charged when a signal indicating the end of the engine braking state is generated. As the signal indicating the end of the engine braking state, for example,
The accelerator pedal position signal can be used.

According to the invention, the output signal of the speed sensor or of the terminal 50 is evaluated for the detection of an impending start of the internal combustion engine. When the driver operates the ignition key when starting the internal combustion engine, the starter is energized, and a voltage is applied to the terminal 50 at that time. If the device detects that this voltage has been applied, the recharging process is started. The evaluation of the terminal 15 is not very suitable. This is because when only the ignition system is switched on, a voltage has already been applied to this terminal. In this case, the driver may switch on only the ignition system and start the internal combustion engine only at a later point in time.

It is particularly advantageous to start the charging process when the first pulse of the speed sensor occurs. In general, a segment sensor or an increment sensor (which sends out pulses at regular intervals) is used as the rotation speed sensor.

In addition to this signal, further signals can also be evaluated in order to detect an imminent start.

FIG. 3 shows various signals over time. 3a shows the voltage at terminal 15 over time, and FIG. 3b shows the voltage at terminal 50 over time. FIG. 3C shows the pulse of the rotation speed sensor 180. FIG. 3D shows the voltage U of the capacitor 145, and FIG. 3E shows the current I flowing through the load.

FIG. 3 shows the switch-on state before the first fuel injection. At time t0, the driver operates the ignition key and the voltage at terminal 15 increases. Time point t1
Then, the starter is energized, which corresponds to an increase in the voltage at terminal 50.

Shortly after the time point t1, the first pulse of the rotation speed sensor N appears. According to the present invention, the charging of the capacitor 145 is started at this time t1 and at the time when the first rotation speed pulse N appears. That is, from time t1,
Proceed accordingly in the case of phase 7 shown in FIG.

As a result, until time t2, the current rises and falls again in each case, and the voltage U rises stepwise to the value U1. When this value is reached at time t2, the capacitor 145
Is fully charged. This state corresponds to phase 7 in FIG.
Corresponds to the state of the capacitor after fuel injection.

At time t3, the first fuel injection in the internal combustion engine continues and continues until time t4.

Between times t3 and t4, phases 1 to
5 is processed. Subsequently, a new recharging process follows to recharge the capacitor. At each fuel injection,
The time lapse of FIG. 2 proceeds.

FIG. 4 shows this procedure using a flowchart. In the first step 400, it is detected whether the voltage of the terminal 15 has been increased. In the following inquiry unit 410, it is checked whether a voltage is applied to the terminal 50. If no voltage is applied to the terminal 50, an inquiry 420 follows, which checks whether a speed pulse has occurred.
If no rotation speed pulse has been generated, a new inquiry unit 410 follows. If a voltage is applied to the terminal 50 or if the speed signal N is present, the charging process of the capacitor continues at step 430 (as shown in FIG. 3 from the time t1).

As shown, two inquiry units can be used. However, it is also possible to perform only one of the inquiry units.

It is particularly advantageous to monitor the terminal 15 described above. When the driver activates the ignition key, a voltage is applied to this terminal. In this case, it is advantageous to evaluate the terminal 15 before the activation of the starting device, in which case the supply voltage is generally higher than after activation of the starting device. In this embodiment, step 430 includes step 4
Performed immediately after 00.

Another embodiment is shown in FIG. First
In step 500, it is detected that an operation state in which fuel injection is not performed has occurred. Such an operating condition occurs, for example, when an engine brake is activated. The operation of the engine brake is detected by evaluating the accelerator pedal or the rotational speed. Subsequent inquiry unit 510
Is checked to see if an accelerator pedal actuation has occurred. The operation of the accelerator pedal indicates the end of the engine brake operation state. When the accelerator pedal is not operated, a new inquiry unit 510 continues. If the accelerator pedal has been actuated, the charging process of the capacitor continues at step 520 (as shown from time t1 in FIG. 3).

[0052]

According to the present invention, even during the first metering after the state in which fuel injection is not performed, the valve can be switched at a high speed to accurately meter the fuel.

[Brief description of the drawings]

FIG. 1 shows a circuit arrangement of the device according to the invention.

FIG. 2 shows various signals shown on a time axis.

FIG. 3 shows various signals shown on a time axis.

FIG. 4 is a flowchart.

FIG. 5 is a flowchart.

[Explanation of symbols]

 100 to 103 Load 105 Voltage source 110 High side switch 115 Switching means 120 to 123 Low side switch 125 Resistance means 160 Control unit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Harald Schuler Germany Backnang Briandstrasse 7

Claims (7)

[Claims] 1. A method for controlling an electromagnetic load, for example, an electromagnetic valve for controlling fuel injection of an internal combustion engine, wherein a charge charged in a charging means is recharged at the start of control of the load. A method for controlling an electromagnetic load, comprising: charging a charging means after the state where injection is not performed and before the first fuel injection. 2. The method of claim 1, wherein the charging means is charged when a signal indicating an impending start-up process is generated. 3. The method according to claim 1, wherein a speed signal is used as a signal for indicating an imminent starting process. 4. The method according to claim 1, wherein the signal at terminal 50 is used as a signal to indicate an imminent starting process. 5. The method according to claim 1, wherein the charging means is charged when a signal indicating termination of the engine brake operating state is generated. 6. The method according to claim 5, wherein an accelerator pedal position signal is used as the signal indicating the end of the engine brake operation state. 7. A control device for an electromagnetic load, for example, an electromagnetic valve for controlling fuel injection of an internal combustion engine, wherein the electric charge charged in the charging means is recharged at the start of the control of the load. A method for controlling an electromagnetic load, wherein a means for charging a charging means is provided after a state where injection is not performed and before the first fuel injection.