EP1044323B1 - Electromagnetic injection valve - Google Patents

Abstract

The invention relates to an electromagnetic injection valve (1) comprising two counterwound magnet coils (SP1, SP2) which have identical characteristic quantities and which are placed on the same magnetic circuit so that the force effects of the magnet coils (SP1, SP2) are nullified when they are flown through by the same excitation current. By virtue of the double coil (SP1, SP2) having a canceling effect, the actual energizing process of the valve (1), i.e. the opening of the same, is transformed in one of both coils in a deenergizing process. The rapid current decay is now determined by dimensioning the extinction voltage (UZD2). As a result, it is possible to obtain rapid force build-up times without increasing the supply voltage (Ubatt). The valve can be controlled by using a conventional switching output stage or by using a current-controlled switching output stage. It is also possible to shorten the closing process by reversing the differential current (Id) during deenergizing.

Description

State of the art

The invention relates to an electromagnetic Injector with double coil, in which a first and second solenoid with the same parameters on the same Magnetic circuit are arranged, one end of which together a supply voltage and its other ends individually with a first and second switching means of an electronic Drive circuit are connected, one of which Control circuit controllable hold circuit parallel to first solenoid is switched.

Such an electromagnetic injection valve is off DE-OS 2 306 007 known. With the known Electromagnetic injection valves serve two or more Magnet coils on the same magnetic circuit and one electronic functionally adapted to this arrangement Control device for this, the shut-off device of the Injector to open and close by by a first excitement a shut off from his closed state opening electromagnetic Attraction, by a second excitement one that Barrier after it has been opened once in its Electromagnetic holding open state Attraction, and finally through a third arousal an opposite magnetic flux is generated to to quench the induced magnetic flux so that Shut-off device closed from its open state becomes.

General is with an electromagnetic injection valve the current rise and thus the increase in force in the anchor essentially by inductance and resistance the valve coil and the supply voltage Ubatt of the coil certainly. The inductance results from the Number of turns of the coil and the design of the magnetic circuit. In the motor vehicle, the supply voltage is at 12 volts limited. Today's requirements for the on time of a electromagnetic used in motor vehicles Injector led too much with a simple valve coil high currents with previous switching transistors and the existing line resistances not realized can be.

To date, the necessary fast electricity and Force increase in the injection valve when switching on with higher voltage from a booster capacitor with a DC-DC converter or through Recharge is achieved. The DC-DC converter is with magnetic circuits with high Eddy current losses necessary, because here a recharge is included the inductance of the valve is too bad Efficiency. In addition, the recharge with the Valve too long charging times of the booster capacitor to lead. The recharge current leads to excitement in the Magnetic circuit that provides security against leakage and unwanted opening of the valve is reduced.

Objects and advantages of the invention

It is therefore an object of this invention to be a reliable working electromagnetically operated injection valve with the shortest possible on and off times and low Achieve circuit effort.

• in einer ersten Phase ein anfänglicher Ladevorgang bei geschlossenem Ventil stattfindet, wobei beide Schaltmittel bei inaktiver Halteschaltung geschlossen sind und ein relativ langsamer Anstieg des durch die beiden Magnetspulen fließenden Stroms stattfindet,
• in einer zweiten Phase, die eine Öffnungsphase des Ventils ist, der Strom durch die zweite Magnetspule durch Öffnung des zweiten Schaltmittels schnell abgeschaltet wird, während das erste Schaltmittel geschlossen und die Halteschaltung inaktiv bleibt,
• während einer dritten Phase, einer Haltephase, die Halteschaltung aktiviert und damit der Strom durch die erste Magnetspule auf eine Haltestromstärke abgesenkt wird, und
• in einer vierten Phase, die eine Schließphase ist, zum Schließen des Ventils wenigstens die Halteschaltung inaktiviert und das erste Schaltmittel geöffnet wird.

The above object is achieved in a generic electromagnetic injection valve in that the two solenoids are wound in opposite directions, so that their force effects cancel out with the same excitation current, and in that the control circuit controls the switching means during a complete open-hold-close cycle of the valve so that

• in a first phase, an initial charging process takes place with the valve closed, both switching means being closed when the holding circuit is inactive and the current flowing through the two solenoid coils increasing relatively slowly,
• in a second phase, which is an opening phase of the valve, the current through the second magnet coil is quickly switched off by opening the second switching means, while the first switching means is closed and the holding circuit remains inactive,
• during a third phase, a hold phase, the hold circuit is activated and thus the current through the first magnet coil is reduced to a hold current, and
• in a fourth phase, which is a closing phase, at least the holding circuit is deactivated to close the valve and the first switching means is opened.

Due to the double coil with canceling effect Actual switching on of the valve, i.e. opening in the second phase in a shutdown process converted in one of the two coils. The fast one Power drop is now due to the sizing Extinguishing voltage determined. Rapid increases in strength are therefore without an increase in the supply voltage realizable. The control of the injection valve is with conventional switching output stage or by a current-controlled Switching stage can be implemented. By reversing the Residual current when switching off, it is also possible to shorten the closing process. A major advantage The invention thus lies in the simplification and Cheaper end stage. The booster capacitor and the DC-DC converters can be used in the Control unit is omitted. This makes the power amp too Easier to integrate in the control unit.

Further features and advantages of the invention are described in the dependent claims as well as in the following Description of a preferred embodiment of a electromagnetic injection valve according to the invention with Double coil clearly if this description under Read reference to the accompanying drawing.

drawing

Figure 1

shows schematically and in the form of a Block diagram of a preferred circuit of a electromagnetic injection valve with Double coil in connection with power amplifiers of the driving circuit; and

Figure 2A to 2E

shows waveforms of in the circuit of Figure 1 occurring signals depending on the time to explain how the circuit shown in Figure 1.

embodiment

In the circuit shown in FIG. 1, 1 is an equivalent circuit diagram of an electromagnetic injection valve with a double coil. The magnetic circuit of the injection valve 1 consists of two magnet coils SP1 and SP2 wound in opposite directions. Both solenoids SP1, SP2 have the same parameters, ie number of turns, inductance L and winding resistance R _cu , and their force effect is canceled out due to the opposite winding direction at the same current ISP1, ISP2. Both solenoids SP1 and SP2 are connected at one end to a supply voltage, for example, in the motor vehicle Ubatt = 12 volts. A first switching means S1, which is symbolically represented as a simple controllable switch, is in series with the first magnet coil SP1, is assigned to a current-controlled switching output stage 2 and is opened and closed by a control signal A1 / 2 thereof. In the circuit of the first magnet coil SP1 there is also a current measuring element, which in FIG. 1 is a resistor R _sens in series with the first switching means S1, the voltage dropping across this resistor R _{sens being} proportional to the current ISP1 flowing through it in the circuit of the first magnet coil SP1 is.

A first extinguishing means, for example in the form of a Zener diode ZD1 with the Zener voltage U _ZD1 , is connected in parallel with the first switching means S1 and the current measuring element R _sens . Alternatively, an RC deletion can be provided. The first extinguishing agent ZD1 is used for quickly switching off the current ISP1 through the first magnet coil SP1, as will be explained in more detail below. Furthermore, a holding circuit formed by a control signal 1/1 that can be opened and closed by the current-controlled switching output stage 2 and a diode and a diode is connected in parallel to the first solenoid coil SP1, which serves to hold the open state of the injection valve when the first switching means S1 is open, as explained in more detail below.

There is also a series of SP2 solenoids second can be opened and closed by a control signal A2 Switching means S2, which is a second extinguishing agent in the form of a Zener diode ZD2 is connected in parallel. The second Switching means S2 is of an unregulated simple Switching stage 3 actuated. The parallel to the second Switching means S2, serving as second extinguishing means, Zener diode ZD2 is used to quickly switch off the current ISP2 through the second solenoid SP2 as below is explained.

As an alternative to the preferred one shown in FIG Circuit design is also possible in others Versions with two simple switching amplifiers without Current control the double coil injector 1 too operate. The current reduction described below However, the holding phase is not possible.

The function and mode of operation of the described and shown in Figure 1 circuit of the electromagnetic Double coil injector based on the in Figure 2 described signal-time diagram described. In figure 2A-2E are the timings of each Control signal A2 for the second switching means (Figure 2A), of the control signal A1 / 2 for the first switching means S1 (Figure 2β), the drive signal A1 / 1 for the hold circuit (Figure 2C), the differential current Id = ISP1 - ISP2 of the currents through the first and second solenoids SP1 and SP2 (FIG 2D) and the individual streams ISP1, ISP2 through the first and second solenoid coil SP1 and SP2 over a total in four Phases, phase 1, phase 2, phase 3, phase 4 divided Open-hold-close cycle from a time t0 to shown at a time t6. The one below Description is in the order of phase 1 to Phase 4

Charging, phase 1; t0-t1:

At t0 both switching means S1, S2 are switched on; A2 and A1 / 2 are ON (Figures 2A and B). The currents ISP1, ISP2 rise relatively slowly (FIG. 2E). The maximum current I ₀ -A = Ubatt / _cu R is at Ubatt = 12 volts less than I ₀ -AUS when switching off in phase 2. Both coils SP1, SP2, that is, both switching means S1, S2 must therefore relatively early before the actual opening of valve 1 can be switched on. The current in this phase can be controlled by a suitable choice of the closing time before phase 2 (opening time tl). An alternative possibility is the current regulation in both coils SP1, SP2. The increase in the current rise at time t0 indicates the time constant Tau = L / R _cu . Due to the same parameters and the opposite winding of the two solenoids SP1, SP2, the differential current Id = ISP1 - ISP2 = 0 (Figure 2D).

Opening the valve, phase 2; t1-t3:

At the beginning at time t1, the current Isp2 is quickly switched off by opening S2 through A2 = OFF with the simple switching output stage 3 with quenching by the second Zener diode ZD2 (FIG. 2A). The current gradient when switching off at time t1 is determined by I ₀ -OFF = U _ZD2 / Rcu and Tau = L / Rcu. With a correspondingly high quenching voltage U _{ZD2 of} the Zener diode ZD2, this current gradient is significantly higher than when switching on. The current ISP1 through the magnet coil SP1 remains switched on at the starting current level I ₀ -ON. Alternatively, this can also be carried out by current regulation (cf. FIG. 2E). The increase in force in the valve is proportional to the square of the differential current Id = ISP1 - ISP2 and therefore very fast (short switch-on time).

Hold phase 3 with valve open: t3-t5:

The residual current Id (FIG. 2D) is lowered to the holding current level at the magnet coil SP1 in the holding phase with the current-controlled switching output stage 2, which contains the current regulator 4, and is regulated by the current control between Id-Hmax and Id-Hmin. Switching off S1 with the control signal A1 / 2 takes place with current quenching by the first Zener diode ZD1. It also applies here that a correspondingly high Zener voltage U _{ZD1 accelerates} the quenching and thus the switching off of the current ISP1. To hold the holding current level, the holding circuit, ie the switching means S1 / 1, is closed by the control signal A1 / 1 (FIG. 2C) and S1 is opened and closed intermittently (FIG. 2β). The holding current ISP1-H is regulated in phase 3 between ISP1-Hmax and ISP1-Hmin.

Closing the valve; Phase 4, t5-t6:

To close the valve either only the current ISP1 switched off by the magnet coil SP1 or, as shown in FIG. 2 is not shown in support of the Closing process with even shorter power off times ISP1 through the coil SP1 with simultaneous short Turning on the current ISP2 through the solenoid 2 off. The differential current Id and thus the The effect of the force is reversed.

Figure 2 also shows in phases 2, 3 and 4 with the Measures according to the invention achievable high negative Current gradients through the entered time constants Dew are symbolized.

With the double magnetic coil provided according to the invention the actual switch-on process has a canceling effect of the electromagnetic injection valve, i.e. its opening in phase 2 in a shutdown in one of the two Magnetic coils converted. The rapid power drop will determined by the dimensioning of the quenching voltage. Fast rise times of the force are without it Measures increasing supply voltage can be implemented. The control of the electromagnetic injection valve is with conventional switching amplifier or, as in the above preferred embodiment, with current-controlled Switching stage can be implemented. By reversing the Residual current Id when switching off in phase 4 is also possible to shorten the closing process.

A major advantage of the invention thus lies in the Simplification of the final stage. The booster capacitor and the DC-DC converter in the control unit omitted. This makes the power amplifier easier to use Integrate control unit.

Claims (11)

1. Electromagnetic injection valve (1) with a double coil, in which a first and second solenoid (SP1, SP2) with identical characteristic variables are arranged on the same magnetic circuit, the one ends of which are jointly connected to a feed voltage (Ubatt) and the other ends of which are individually connected to first and second setting means (S1, S2) of an electronic driving circuit (2, 3), a holding circuit (S1/1) which can be driven by the driving circuit being connected in parallel with the first solenoid (SP1), characterized in that the two solenoids (SP1, SP2) are wound in opposite directions so that their force effects cancel one another out when they have the same excitation current, and in that the driving circuit actuates the setting means (S1, S2) during a complete opening/holding/closing cycle (t0-t6) of the valve (1) in such a way that

   in a first phase (t0-t1), an initial charging process takes place with the valve closed, both the setting means (S1, S2) being closed when the holding circuit (S1/1) is inactive, and a relatively slow rise in the current (ISP1, ISP2) which flows through the two solenoids taking place,

   in a second phase (t1-t3), which is an opening phase of the valve, the current (ISP2) through the second solenoid (SP2) is switched off quickly by opening the second switching means (S2), while the first setting means (S1) remains closed and the holding circuit (S1/1) remains inactive,

   during a third phase, a holding phase (t3-t5), the holding circuit (S1/1) is activated and as a result the current (ISP1) through the first solenoid (SP1) is lowered to a holding current strength (ISP1-H), and

   in a fourth phase (t5-t6), which is a closing phase, at least the holding circuit (S1/1) is deactivated in order to close the valve, and the first switching means (S1) is opened.
2. Injection valve according to Claim 1, characterized in that the driving circuit sets the currents flowing through the two coils (SP1, SP2) in the first phase (t0-t1), by determining the closing time of the two switching means (S1, S2).
3. Injection valve according to Claim 1, characterized in that, in the first phase (t0-t1), the driving circuit (2, 3) sets the strength of the current flowing through the solenoids (SP1, SP2) by regulating the current flowing through both solenoids.
4. Injection valve according to one of Claims 1-3, characterized in that first extinguishing means (ZD1) which increase the current gradient when the current through the first switching means (S1) is switched off are connected in parallel with the first switching means (S1).
5. Injection valve according to one of Claims 1-4, characterized in that second extinguishing means (ZD2) which increase the current gradient when the current through the second switching means (S2) is switched off, and thus accelerate the opening of the valve at the start of the second phase (t1-t3), are connected in parallel with the second switching means (S2).
6. Injection valve according to Claim 4 or 5, characterized in that the extinguishing means each have a Zener diode (ZD).
7. Injection valve according to one of the preceding claims, characterized in that a current measuring element (R_sens) is provided in the circuit of the first solenoid (SP1), and the driving circuit (2, 3) has a current regulator (4) which is connected to the current measuring element (R_sens), at least for regulating the current (ISP1) flowing in the circuit of the first solenoid (SP1).
8. Injection valve according to Claim 7, characterized in that the current measuring element (R_sens) is a resistor which is connected in series with the first switching means (S1).
9. Injection valve according to Claim 7 or 8, characterized in that, in the second phase (t1-t3), the current regulator (4) of the driving circuit (2, 3) regulates the current (ISP1) flowing through the magnetic circuit of the first solenoid (SP1).
10. Injection valve according to one of Claims 7-9, characterized in that, during the holding phase (t3-t5), the current regulator (4) of the driving circuit (2, 3) regulates the current flowing through the magnetic circuit of the first solenoid (SP1) by intermittently activating/deactivating the holding circuit (S1/1) between a minimum and maximum holding current (ISP1-H-min., ISP1-H-max.) when the first switching means (S1) is closed.
11. Injection valve according to one of the preceding claims, characterized in that, at the start of the fourth phase (t5-t6), the driving circuit (2, 3) briefly closes the second switching means (S2) when the first switching means (S1) are opened.

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