FR2538942A1 - Device for control of electromagnetic unit(s) with rapid action, such as electrovalve(s) or injector(s) - Google Patents

Abstract

Device with energy accumulation circuit characterised in that the energy accumulation circuit comprises, across the actual terminals of the winding 2 of the said electromagnetic unit, a circuit for charging and discharging the aforesaid capacitor 7 comprising a charging path with passing diode 6 for the self-induction current produced on the breaking of the supply to the said winding, and in that there is provided a circuit for controlling charging of the capacitor with energising pulses for the said electronic supply switch 3, these pulses being suitable to allow the charging of the capacitor by the self-induction current of the said winding, but unsuitable for causing actuation of the aforesaid electromagnetic unit.

Description

Control device for electromagnetic organ (s) with rapid actuation, such as solenoid valve (s) or injector (s).

 The invention relates to a device for controlling a magnetic device (s) requiring rapid actuation, such as solenoid valves for servo-control or for metering any fluid flow rate or injectors for internal combustion engines in particular.

 I1 is known to actuate such electromagnetic members by an electronic control comprising for each member a power circuit with electronic switch responding quickly to low power trigger signals to supply the actuation winding of said member.

An important problem from the performance point of view, in particular cadence and precision, and to quickly establish the current in the winding, It has already been recommended for this purpose to associate with the control an energy storage circuit with capacitor charge, which is subjected to discharge control means in the initial triggering phase of the or each electromagnetic member considered. This makes it possible to obtain a rapid triggering under a discharge voltage which the winding would not permanently withstand, as being much greater than the normal supply voltage of the latter, the latter not being sufficient to ensure the maintenance of the electromagnetic organ in its initial rapid actuation state.

 your commands responding to this principle are generally complex in the association made with the energy storage circuit.

 The object of the present invention is to simplify the construction thereof and the court.

 Essentially, for this purpose the electromagnetic organ control device with rapid actuation according to the invention, comprising a power circuit with electronic switch responding to low power external trigger signals to supply the actuation winding of said organ, and an energy storage circuit with capacitor charge subjected to discharge means in the initial phase of actuation of each electromagnetic member, is characterized in that said energy storage circuit comprises at the very terminals of the winding of said electromagnetic member, a circuit for charging and discharging the aforementioned capacitor, comprising a charging channel with diode pass-through for the self-induction current generated at the interruption of supply of said winding, and a circuit for charging the capacitor with rapid pulses of excitation of said electronic power switch, these pulses being adapted to allow the charging of the capacitor by the self-induction current of said winding but unfit to cause actuation of the electromagnetic member concerned, and the discharge path of the capacitor comprising an electronic switch controllable in synchronism with said external signals for triggering the electronic switch said power supply to said electromagnetic member for at least the above-mentioned initial actuation phase.

 It will be noted that it is thus advantageously made use of the winding itself of the electromagnetic member to be actuated as the winding of the self of the energy accumulation circuit.

 In a control common to several sequentially actuated electromagnetic members, the winding of only one of these can be used as a choke or all can wander very simply if necessary, as will be seen in the following.

Several illustrative embodiments of the invention are in fact described below by way of example and with reference to the appended drawing, in which
fig. 1 is an electrical schematic diagram of a control device according to the invention,
fig. 2 is a variant relating to the control of several electromagnetic members;
fig. 3 is an illustrative timing diagram of a sequence of signals corresponding to a mode of actuation of the electromagnetic members in the case of FIGS. l and 2;
fig. 4 is an electrical diagram of an embodiment of a control device according to the invention piloted in two phases of each actuation period of each of the electromagnetic members concerned;
fig. 5 is an illustrative timing diagram of a sequence of signals governing the operation of the control device object of FIG. 4.

 In the diagram of fig. l have been designated by the symbols + and -the polarities of a direct current source, such as a motor vehicle battery, between which are connected in series through a diode 1, a winding 2 of an injector of the fuel consumed by the engine and an electronic switch 3 with a control electrode 4. Between the switch 3 and the terminal of the winding 2 to which it is connected, there is provided a bypass 5 with diode 6, mounted. passing to an energy storage capacitor 7. This branch has a common point 8 with another branch 9 provided in parallel with the winding 2 and provided with an electronic switch 10 with control electrode 11.

 It is to be seen that the winding 2 is here used itself as the inductor for charging the capacitor 7 by way of the bypass 5 with diode 6, outside of the effective actuation period of the reader, by exciting the conduction from a pulse generator and by its control electrode 4, the switch 3, in an improper manner to cause the actuation of the electromagnetic member with winding 2, but sufficient to allow repeated pulses of current of self induction in the winding 2, which charge the capacitor 7 through the diode 6 in the cut-off phase of the switch 3, at a voltage much higher than that of supply.

 Said excitation frequency can be of the order of kilohertz and in particular with MOS type power switches, of 150 kHz for example.

It is to be seen while the capacitor 7 is thus charged, the actuation of the winding injector 2 can be caused in response to a synchronous control pulse applied to both the control electrodes 4 and it of the switches 3 and 10 , so that :
- in a first phase, called the call phase, the capacitor 7 discharges through the winding 2 and the switch 3, causing the desired rapid actuation of the in3ector, at a decreasing voltage up to that of battery;
- In a second phase, called holding, the injector is kept open by supplying its winding 2 under the battery voltage and by the switch 3, as long as it is requested to close by said synchronous control pulse applied thereto.

 There is shown in phantom in FIG. 1 the possible mounting of other windings 12, 13 of injectors, each provided with their own actuation control switch 14, 15, of which it suffices that 1 pulse-control applied to the corresponding electrode 16, 17, is synchronous with another pulse applied to the control electrode 11 of the switch 10, in order to obtain in the desired sequence the same operation of injector as that exposed previously, on the condition of also inhibiting in each phase of actuation the excitation in frequency of the switch 3 used to bring into play the winding 2 for charging the capacitor 7 by self-induction.

 There is shown in FIG. 2 the possibility, in a control of multiple injectors, of using all the windings of the injectors as inductors for charging the capacitor 7 by connecting them to each other and to the common point 8, by means of passing diodes 18, 19 in the direction of charge of the capacitor 7.

 The timing diagram in fig. 3 illustrates an example of control signals ensuring the pre-exposed operation in the case of several injectors of FIGS. 1 or 2.

 your line I corresponds to the aforementioned excitation pulses which are validated by the high state of the signal of the line il, determining the charge phases TC of the capacitor 7 and applied for this purpose to the single control electrode 4 of the switch 3 in the case of FIG. 1 and to the control electrodes 4, 16, 17 of the switches 3, 14, 15 in the case of FIG. 2.

The low state of the signal of line II authorizes the injection phases TI by its application to the control electrode 11 of the switch 10, and the injectors are actuated sequentially by an individual synchronous pulse applied to the electrode control of their own power switch, as indicated by lines -III, IV and V, it being understood that the low state of the signal of line II corresponds to an inhibition of application of the aforementioned excitation pulses, of which reports line I.

 Within the framework of the invention, it is also possible to control, if desired, the respective durations of said inrush and holding phases as well as the level of current maintained in the holding phase, as illustrated in exemplary embodiment. of fig. 4.

 In the latter, the elements corresponding to those of FIG. 2. The electronic switch 10 is here constituted by a thyristor, the trigger 11 of which is connected to the output of a photocoupler 20 whose input photodiode 21 is subjected to an injection control signal C as will be seen more far. The electronic switches 3 and 14 are constituted by NOS elements of type N, the electrodes 4 and 16 of which cause conduction when they are in the high state of their control logic. The latter comprises for switch 3, three NI doors 22, 23, 24, and for the switch 16 three NI doors 25, 26, 27, each group of doors being in parallel with a resistor 28 supplied with a regulated voltage + V lower than the battery voltage.

 The first gate of each group NI 22, NI 25, has its two inputs respectively subjected, 1Dune to the aforementioned excitation pulses of high frequency, emanating from a clock, designated by CK and illustrated in line I of fig. 5, the other at signal C illustrated in line II and validating in the low state the charge periods TC of the capacitor 7 as indicated in line III, while it validates in the high state the injection periods TI.

It is applied to the two entrances of the second door of each group,
NI 23, NI 26, a synchronous signal with the rising edge of the control signal
C, designated by Ca for the gate NI 23 and by Ca 'for the gate NI 26, these signals being illustrated in lines 4 and 6 of the timing diagram of FIG. 5, and determining in their low state the duration of the respective phase of calling each injector on opening, under the energy accumulated by the capacitor 7 and released by conduction of the thyristor 10 in response to the high level of the signal C.

A signal designated by Cm for the NI 24 door and Cm 'for the door is applied to one of the inputs of the third door of each group9
NI 27, these signals being illustrated in lines V and VII of FIG. 5, and relaying the signals Ca, Ca 'in their low state, to govern said phase of maintaining the opening of the injectors. In this phase, the current flowing through the windings considered is then limited by a chopper circuit governing the second between the corresponding gate NI 24 or NI 27.

 This chopping circuit comprises, for each injector, a transistor 28, the base of which is connected to the power supply conductor of the winding, between the switch 3 or 14 and a resistor 29, which is chosen to be of value such that when the current limits holding is reached or exceeded, the transistor 28 is biased to the conduction. The latter's collector, connected to the voltage source + V by a resistor 30, is also connected to the two inputs of an NI gate 31, the output of which is connected to the second input of the aforementioned NI gate 24 or 27.

So, in each holding period corresponding to one of the signals
Cm or Cm ', when the holding current exceeds the chosen value, the transistor 28 conducts, so that a low level is then applied to the inputs of your corresponding NI 31 gate, the output of which goes high , which has the effect of switching the door output to the low state
NI 24 or 27, so that the conduction of the corresponding MOS switch 3 or 14 is interrupted until the transistor 28 is reblocked, and the holding current is thus limited by a repetitive chopping in this second injection period.

 Of course, other control modes than those described can still be imagined without departing from the scope of the invention.

Claims (4)

 1. A device for controlling a rapidly actuated electromagnetic member, such as a solenoid valve or an injector, comprising a power circuit with electronic switch responding to external low-power trigger signals to supply the actuation winding of said member, and a circuit for accumulating energy charged by a capacitor subjected to discharge means in the initial phase of actuation of each electromagnetic member, characterized in that the circuit for accumulating energy comprises, at the very terminals of the winding (2) of said electromagnetic member, a circuit for charging and discharging the aforementioned capacitor (7) comprising a charging diode charging channel (6) for the self-induction fuel generated at the interruption of supply to said winding, and that a charge control circuit of the capacitor with excitation pulses of said electronic power switch (3) is provided, these pulses being specific to ttre the charge of the capacitor by the self induction current of said winding, but unfit to cause the actuation of the aforementioned electromagnetic member, the discharge path comprising an electronic switch (10) controllable in synchronism with said external switch trigger signals aforementioned electronics (3) for supplying said electromagnetic member, for at least the aforementioned initial actuation phase.  2. Control device according to claim 1, for equipment with multiple electromagnetic members, such as solenoid valves or injectors, in particular for internal combustion engine, characterized in that said energy accumulation circuit is placed at the terminals d only one of the windings of said members arranged in parallel, the dialing switch of this winding being -only subject to said charge control circuit of the capacitor, and each individual tripping signal of one of said members being accompanied by a signal for triggering the electronic switch (10) of the discharge path of the accumulation circuit, thus ensuring said initial high energy actuation phase for each organ considered.  3. Control device according to claim l, for equipment with multiple organs, such as solenoid valves or injectors, in particular for internal combustion engine, characterized in that said energy accumulation circuit is placed at the terminals of all the windings: (2, 12, 13) of said members arranged in parallel, which are connected to each other and to the capacitor (7) by diodes (6, 8, 19) passing for the self-induction current and whose power switches (3, 14, 15) are all subject to said capacitor charge control circuit, each individual trigger signal from one of said members being accompanied by a trigger signal from the electronic switch (10) of the discharge path of the accumulation circuit, thus ensuring said initial high energy actuation phase for each organ considered.  4. Control device according to any one of the preceding claims, characterized in that the control circuit of the or each electronic power switch comprises a holding phase following the abovementioned initial phase and with limited current obtained at using a chopper circuit (28 to 31) responding to a current limit value detected in the supply circuit of the winding considered.