AU5853099A - Electronic circuit for pulse generation - Google Patents

Description

BO 58051 OWO B 1999-08-12 Werner Arnold Georgstrasse 13 41363 JOchen GERMANY Electronic circuitry for pulse generation The invention concerns an electronic circuitry for generation of current/voltage pulses with a direct voltage source, at least one charging energy accumulator, in particular a first capacitor, connected to the poles of the direct voltage source, at least one pilotable/triggerable switching element and at least one device op erated by the generated pulses. Circuitries of this kind are used particularly for the creation of pulses serving to generate ignition sparks in order to ignite, for example, a gas mixture in a com bustion engine. Another application, for example, consists in permitting pulsed operation of la ser diodes or piloting or driving/triggering of reluctance motors. Generally, such a circuitry can be employed whenever a device of any kind is to be operated by means of current or voltage pulses. Depending on the specific application, the pulses can be low- or high-voltage pulses. In regard particularly to the generation of ignition sparks it is generally known to charge, for instance, an energy storing capacitor in a pulsating manner and subsequently to short-circuit the charge accumulated during the charging proc ess using a pilotable/triggerable switching element, such as a thyristor, via the primary winding of a transformer. The current/voltage pulse generated by this short-circuit is stepped up to the kilovolt range in the transformer so that a volt an be tapped at the secondary coil of the transformer, which makes it pos -1$ -o4 sible to cause a spark to arc over an electric arc gap, e.g. in a spark plug. This spark then serves to ignite the gas mixture in the combustion chamber of an engine. Circuits functioning according to the described principle of pulsed discharge of a capacitor are know from e.g. US 5 245 965 and EP 0 378 714. These circuits all have a common drawback in that the charging time of the en ergy storing capacitor is relatively long in comparison with the discharging time. This means that, for the requirement of providing a maximal ignition energy with each ignition pulse, the achievable pulse sequence will be limited at the upper end. For example, in a 6-cylinder car engine, 300 ignition pulses per second are re quired for up to 6000 rpm. In other words, an ignition pulse has to be generated every 3.3 msec. For the short charging times of the energy storing capacitor thus needed, which lie between 1 and 1.5 msec, the required energy sources must have a very low internal resistance and supply a high power in combina tion with the circuit. A further disadvantage of the known ignition systems is that, due to the genera tion of the ignition spark in the discharging process of the energy storing ca pacitor, after spark generation no further energy can be fed to the electric arc thus formed, so that the spark duration is normally only about 100 - 300 psec. Particularly in partial-load operation of a combustion engine this can lead, among other things, to incomplete combustion and a higher emission of pollut ants. The object of the invention is to provide an electronic circuit for energy-efficient generation of current/voltage pulses in which, after pulse generation, energy can continue to be fed into the device operated by the circuit so that, when the circuit according to the invention is used in an ignition system, for example, en ergy can continue to be fed to the standing electric arc after generation of the ignition spark, such that clean and low-emission combustion can take place e er the most varied combustion conditions, during start-up or under full O4 load, for instance. A further object of the invention is to enable a higher pulse frequency than in conventional circuits, even at maximal energy withdrawal. This problem is solved by the invention in the manner that, in addition to at least one charging energy accumulator, in particular developed as a first capacitor, connected to the direct voltage source (e.g. battery), the electronic circuit is provided with at least one further energy accumulator, in particular a second capacitor which is connected in series with at least one switching element, in particular a pilotable/triggerable switching element, and with the pulse-operated device, and can thus be connected via at least one switching element with the poles of the charging energy accumulator, whereby electric power can be transmitted to the device in the charging and/or discharging process of at least one of the further energy accumulators. A circuitry of this kind makes it possible to generate the pulses after pilot ing/triggering of the switching element in such a manner that the electric charge of the charging energy accumulator, i.e. in particular the first capacitor, is transmitted through any desired connected device to a further energy accumu lator, e.g. a second capacitor. In accordance with a first preferential embodiment, the electric charge trans mitted to the energy accumulator or the further energy accumulators can, for ex ample, be used, for the purpose of continued pulse generation, to cause an in crease in the difference in potential between a charging energy accumulator and one or more of the further energy accumulators. For this purpose the circuit is so designed that the polarity of one or more en ergy accumulators is switchable. In the case of the energy accumulators this can be both a charging energy accumulator and one or more of the mentioned further energy accumulators. The switchover can be effected simply in that, within the electric circuit of the circuitry the order of the connection poles of one or more of the energy ac cumulators in the direction of current flow can be reversed. This switchabil ity/reversibility enables the polarity of the charge present in the switchable en ergy accumulator to be changed relative to the other energy accumulator.

During a pulse-like charge transfer from the charging energy accumulator to a further energy accumulator, the latter can be charged at the most up to the volt age of the charging energy accumulator. Once the charge has been transferred there will generally no longer be a difference in potential between the charging energy accumulator and the further energy accumulator, unless the charge at the further energy accumulator is dissipated. Due to the described switchover, the difference in potential between the charg ing energy accumulator and the further energy accumulator will correspond, after the switchover, at the most to double the voltage present in the charging energy accumulator. If, by actuation of the switch, a pulse-like charge transfer is now generated, the device can be operated with an artificially raised voltage and thus with a higher power consumption. After potential equalization has occurred, the polarity of the energy accumulator can again be switched over for the purpose of generating the next pulse. Whether full equalization of potential between the charging energy accumulator and the further energy accumulator actually occurs depends to a large extent on the charging time constant and the switchover timing, which in turn depends on the desired pulse frequency with which the device is to be operated. The mag nitude of the voltage increase is thus a function of these parameters and further depends on how much of the charge is additionally supplied out of the energy accumulator into the pulse-operated device. Voltage increases of several 10% are realistic. A pulse-operated device can thus be operated in a simple manner with a volt age that is greater than the voltage at the charging energy accumulator, so that a lower operating voltage can be sufficient here. Since a voltage increase is only possible after an initial charging of at least one of the further energy accumulators, it is additionally advantageous if, during the first charging process, the charge does not pass through the pulse-operated d . s can, for example, be achieved by a bypass circuit and can be nec sary whe safe operation of the device with the voltage of the first pulse cannot otherwise be guaranteed. A bypass circuit can, however, be dispensed with when the charging energy accumulator, which normally has a very high capac ity, is charged from the voltage source with a high charging time constant and, simultaneously with the first charging of this energy accumulator, the further energy accumulator(s) can also be charged with a high time constant as well. In this case, no pulse will be generated and the further energy accumulator(s) will be slowly charged via the device. The switchability of any desired number of energy accumulators in the circuit presents a further advantage in that, when a device is used that has an in ductance, it is possible, in the event of a mutual induction voltage occurring, resulting, for example, from the decaying magnetic field in the negative half wave of the generated pulse, to connect all the partial voltages present in the device and the energy accumulators in maximally additive series, in order to make use of the mutual inductance voltage and to realize an effective alternat ing-voltage pulsed-operation of the device in resonance. It should furthermore be mentioned that the stated energy accumulators may be not just single accumulator elements but can also be an arrangement, in par ticular a series and/or parallel connection of accumulator elements such as ca pacitors. In an alternative or simultaneous embodiment, the electric charge transmitted to the further energy accumulator can, after the first pulse generation, also be used either to generate a subsequent pulse or to supply additional energy in the form of direct current or alternating current energy to the pulse-operated device. At least one of the energy accumulators provided thus supplies part or all the energy, during both its charging and discharging process, to the pulse-operated device. In particular for the use of the electronic circuit according to the invention in the example of an ignition system of a combustion engine, it is thus possible to supply more energy to the struck electric arc or to fire the next spark. The spark duration will thus be regulatable or the maximal speed of the engine can thus be increased, since an ignition spark can be generated during both charging and L 4 LU X% /I discharging of the further energy accumulator(s) and it is not necessary to wait until a full charging/discharging cycle has run before the next ignition spark. In the arrangement according to the invention it is further advantageous if the circuitry has both an electric circuit for charging and an electric circuit for dis charging of each of the further energy accumulators, which in particular differ from each other. In this case, each of the further energy accumulators should be arranged in a section of the electric circuit which forms part of both electric circuits. If, furthermore, the pulse-operated device is also arranged in an electric circuit section located in both the charging and the discharging electric circuit, both during the charging and discharging processes of one of the further energy accumulators the transmitted charge can be very simply made to pass through the pulse-operated device, thus piloting it. It is especially advantageous in the described arrangement if, during both charging and discharging of one of the further energy accumulators or several energy accumulators, the electric charge is pulsed through the device in the same direction. This ensures that the polarity at the pulse-operated device will remain the same during both the charging and discharging process. Alternatively, a first pulse-operated device can be located in the charging circuit and a second pulse-operated device in the discharging circuit. An arrangement of this kind makes it possible to pilot/drive various pulse-operated devices dur ing the charging and discharging of one or more further energy accumulators. It is, for example, conceivable in this case to pilot different current-carrying wind ings of a reluctance motor or another motor one after the other. Further devices can, of course, be arranged in the charging and discharging circuit in each case. It is also conceivable during the charging cycle of the further energy accumula tor in an application to fire a first spark plug and during the discharging cycle of the same energy accumulator to fire a second spark plug, for example. In an ot ication, different laser diodes can be alternately piloted/triggered by , se s ot t, for example, in a laser diode array the repetition frequency of ~,w_) QNr one single laser diode can be lowered, which has a positive effect on the life of the diode or pulse-operated devices in general. It is especially advantageous if the charging and discharging circuit in each case has at least one, preferably two switching elements and these are in par ticular pilotable/triggerable. By means of the pilotable/triggerable switching ele ments it is then possible to alternate between pulse-like charging and discharg ing of the further energy accumulators. The piloting/triggering can, for example, be programmable and, in particular, be effected by a motor/engine electronic control system. If in this case, both during charging and discharging of the energy accumulator, current always flows through the pulse-operated device in the same direction, energy can be further supplied to the pulse-operated device with constant po larity. The amount of energy further supplied to the pulse-operated device in an alter nating cycle can be varied by means of the circuitry according to the invention. This is made possible by the fact that, between charging and discharging of the energy accumulator, the switchover occurs before the charging or discharging limit is reached. The energy supplied can be adjusted as a function of how far the charge in the energy accumulator approaches the charging or discharging limit. The amount of energy thus results mainly from the difference in the volt age present at the energy accumulator at the switchover time points. A maximal energy supply is thus given when the charging or discharging limits are reached at the point in time of the switchover. In regard to the application of the circuitry according to the invention in the igni tion of a combustion engine, this means that the electric arc is first struck with a high-voltage firing pulse and then, with a standing electric arc, the energy sup ply can be adapted to the prevailing electric arc conditions by alternating be tween charging and discharging of the energy accumulator. In particular in lean mix engines, or when strong turbulence occurs in the combustion chamber, it is adva eous if a higher energy can be supplied to the electric arc. Lid -0 -0 In order to ensure that, for example, for optimal energy supply the charge al ways flows through the pulse-operated device in the same direction during charging and discharging, the path of the charge flow in each electric circuit can, for example, be determined by diodes. For this purpose, in a preferential embodiment, a rectifier arrangement can be located in series with an energy accumulator, with a pulse-operated device arranged between the direct voltage tapping points of the said rectifier arrangement. The diodes used to define the direction can, in particular, be laser diodes, so that by means of the circuitry according to the invention, a simple combination of operated laser diodes with a further pulse-operated device is made possible. Since several diodes may be used, laser diodes with different radiation spectra can be selected so that, for example, during the charging and discharging proc esses, different light spectra are emitted. As an alternative to the use of diodes, it is also possible to define the path of charge flow in each electric circuit by pilotable/triggerable switching elements. During the charging process of an energy accumulator, for instance, all pilo table/triggerable switches located in the charging circuit of the energy accumu lator will first be closed, while at the same time all those switches located in the discharging circuit will be opened. The pilotable/triggerable switches can then be alternately switched to effect the alternation between charging and dis charging. As already cited several times as an example, one preferential use of the cir cuitry according to the invention is to provide an ignition spark for a combustion engine. For this purpose, the device operated with the pulses can be a trans former, through the primary coil of which the charging pulse of at least one of the energy accumulators passes. The current/voltage pulse generated during the charging process is stepped up with the aid of the transformer to a high voltage pulse which can be tapped at the secondary coil. This high-voltage pulse is then fed to a spark plug which ignites the gas mix. n ~nerally possible to use the transformed high-voltage pulse to ignite ion ized g s. Instead of spark plugs, it is therefore alternatively possible to oper Y$rrJ ate, e.g. fluorescent or neon tubes with the circuitry according to the invention. These can then be piloted with such an increased frequency that the flickering known in ordinary tubes is no longer detectable by the human eye. Due to this higher frequency, the typical 50 Hz dither of the transformer will be eliminated. It is also conceivable to generate sparks in fluids, such as is common in spark erosion. As mentioned above, it is possible by means of the electronic circuitry according to the invention to supply further energy to the standing electric arc once the ignition spark has arc-ed over. This can be direct and/or alternating current en ergy. In order to ensure the supply of the standing electric arc with direct current en ergy, the transformer is preferentially developed as an autotransformer in which there is a connection between the primary and secondary coil. The free end of the secondary coil is in this case connected to one pole of an arc gap while the other pole is connected to frame potential. This arc gap is preferably the spark plug of a combustion engine. If, now, one or several of the pilotable/triggerable switching elements are switched in such a manner that a charge transfer takes place between the first charging energy accumulator and one of the further energy accumulators through the primary coil of the autotransformer, this will, in addition to the gen eration of a high-voltage pulse on the secondary side, result in the simultaneous application of a voltage, in particular a direct voltage, to the spark plug through the connection between the primary and secondary coils, the said voltage can be made so high, through appropriate development of the direct voltage energy source and the charging energy accumulator, that the electric arc will remain standing after firing. To be sure, though the ignition voltage of the electric arc lies at several kilovolts, the electric arc requires only a few 100 volts, in particular 200-400 volts for a gap to be crossed of less than 1 mm. an electric arc struck and maintained in such a way will remain standing, Ai Sit is a ntageous if the grounding conductor of the energy source (direct volt- -10 age source) can be disconnected from the vehicle ground by a switching ele ment that is also pilotable/triggerable. Upon breaking of this connection the definition of the voltage potential at the spark plug is automatically canceled, whereby the electric arc extinguishes. This being the case, it is possible, by means of the pilotable/triggerable switch ing elements, to strike an electric arc during the charging process of the energy accumulator and to maintain the said arc. Depending on the desired spark du ration, which can be determined from the instantaneous engine operating data, for example, the electric arc can be extinguished and subsequently the next ignition spark fired during the discharging process of the energy accumulator, e.g. after one engine revolution. In a construction of this kind it is also possible, as mentioned above, to achieve an increase in the pulse voltage through the described switching over of the energy accumulators and thus of the polarity of the charge relative to the charging energy accumulator. In a further preferential embodiment, the transformer can have several, prefer entially two secondary coils, so that it is possible to fire two spark plugs simulta neously, for example, in the combustion chamber of a combustion engine. In this way, combustion can also be optimized. In another advantageous embodiment of the circuitry according to the invention, a switching element, in particular a diode, blocking the charging current of one of the energy accumulators can be connected in parallel to the primary winding of the transformer and/or to the charging energy accumulator. When the diode is connected in parallel to the primary winding, the mutual in ductance voltage present in the primary winding is short-circuited and the en ergy is fed to the secondary side. When the said diode is connected in parallel to the charging energy accumulator, it is possible to cause an electric oscillation to establish itself after charging of the further energy accumulator and firing of a spark, the positive half-waves of the said oscillation also being transmittable to ndary side. It is thus possible, in a circuitry arrangement in which the charge the charged further energy accumulator is not used to fire another 0 0) new spark, to supply this charge without any further switching element to the secondary side of the transformer. However, it should be remembered that, due to the connection between the primary and secondary coils, the charge of the further energy accumulator will continue to be supplied to the standing electric arc until the voltage at the fur ther energy accumulator falls below the arc voltage in the arc gap, unless the energy source supplies a voltage that lies above the arc voltage of the electric arc. This being the case, there will be a residual voltage in the further energy accu rmulator which reduces the voltage differential between the charging energy ac cumulator and the further energy accumulator, but which can be utilized in the manner described by switching over the further energy accumulator to increase the voltage differential. As an alternative to the diode used, a pilotable/triggerable switching element can also be used as the blocking switching element. Generally speaking, all elements can be used as pilotable/triggerable switching elements that are controlled by current, voltage or inductively, capacitatively, magnetically or optically. It is thus possible to employ semiconductors, e.g. transistors, other switchable and conductive parts or even programmable mi croelectromechanical switches. Switches made of electrically conductive plastic can also be used, such as in known from fuses. By employing pilo table/triggerable switches of this type it is possible to render programmable the entire circuitry arrangement according to the invention, e.g. by means of micro processors, so that, for example, the electric arc duration and supplied energy can be adjusted as a function of the engine conditions by a separate electronic engine control system. In another application, a light emitting element can, for instance be employed as the pulse-operated device. In particular, one might conceive of the use of a la ser diode which is operated in pulsed mode by the circuitry according to the in It should be mentioned that, in the ignition system of a combustion en ((.g ine, t nly one circuitry is employed, but a separate circuitry can be used, for example, for each cylinder. Furthermore, the polarity of the energy source can be selected as desired. In this case care must be taken to ensure that the di odes used are operated in the correct blocking direction corresponding to the polarity used. In a particular embodiment it is thus also possible to combine a circuitry sup plying an ignition spark with another circuitry piloting a laser diode in pulsed mode. If the spectral range of the piloted laser diode is selected such that the emitted light can cause the molecules in the combustion gas mix to ionize, for example, in the focus of the laser beam or to assume highly excited states, it will be possible in an arrangement to route the pulsating light of the laser diode through the arc gap, so that, due to the pre-ionization/excitation the ignition en ergy to be supplied can be considerably reduced. A circuitry arrangement of this kind will permit better and cleaner combustion and, due to the reducible power consumption, make it possible to realize en gines with higher speeds. As mentioned above, in another application a reluctance motor or another motor can be used as the pulse-operated device, in which motor, for example, during the charging process of the further energy accumulator the current passes through a first motor coil and, during the discharging process of this energy ac cumulator, through a further motor coil. Examples of preferential embodiments of the invention are represented in the following figures, in which Figure 1A shows an electronic circuitry according to the invention, in which, during a exchange of charges between two energy storing ca pacitors, the generated voltage pulse passes through a trans former and is transformed to high-voltage for the purpose of strik ing an electric arc. Figure 1 B shows a circuitry according to the invention, in which the polarity of an energy storing capacitor is switchable relative to the charging PAL/4 capacitor.

-13 Figure 1C shows a circuitry according to the invention, in which the polarities of both energy storing capacitors are switchable relative to each other within the circuitry. Figure 2 shows a circuitry according to the invention, in which both pulse like charging and discharging currents, whose direction is defined by diodes, flow through the primary winding of a transformer. Figure 3 is a diagram illustrating the possibility of supplying further energy as alternating current to the struck electric arc. Figure 4 shows a circuitry according to the invention, in which the diodes as shown in Figure 2 determining the direction of flow are replaced by pilotable/triggerable switching elements. Figure 5 shows a circuitry as shown in Figure 4, in which the secondary side of the transformer is equipped with two coils. Figure 6 shows a circuitry according to the invention, in which the direction of the current flow through the primary coil of a transformer is de fined by means of a rectifier arrangement. Figure 7 shows a circuitry corresponding to Figure 6, in which the pulse operated transformer is replaced by a pulse-operated laser diode, wherein the rectifier diodes can also be laser diodes. Figure 8 shows a circuitry according to the invention, in which the charge of a capacitor is transferred to one or two further capacitors and in which a first winding of a reluctance motor is located in the charg ing electric circuit of these capacitors and a second winding of a reluctance motor in the discharging electric circuit. Figure 9 shows an arrangement with two electronic circuitries according to the invention, in which a circuitry for generation of an ignition spark and another circuitry for generation of a laser light pulse is used which pre-ionizes or excites the gas mix to be ignited in the arc gap.

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-14 Figure 1A shows an electronic circuitry according to the invention for the gen eration of current/voltage pulses for the firing of ignition sparks in combustion engines with a direct-voltage energy source 1, a charging energy accumulator 4, in the form of a first capacitor, connected at a distance to poles 2 and 3 of the said direct-voltage source, a pilotable/triggerable switching element 5, and an autotransformer 6, which is operated by the generated pulses, having a primary coil 13 and a secondary coil 14 wherein the two coils are connected to each other. The circuitry also has a further energy accumulator 7, which in the present case is also developed as a second capacitor, whereby this second capacitor 7 is connected in series with the pilotable/triggerable switching element 5 and the primary winding 13 of the autotransformer 6 and is thus connected or connect able via switching element 5 with the poles 2' and 3' of the charging energy ac cumulator 4, so that electric power can be transmitted to the autotransformer in both the charging and the discharging process of the capacitor 7. The charging capacitor 4 shown in Figure 1 is charged quasi continuously, compared to the discharging process, by means of the direct-voltage source 1 via the connecting path between the poles 2 and 2' resp. 3 and 3'. Since, during the charging process of the charging capacitor 4, short time constants play only a secondary role, the distance between the poles 2 and 2' resp. 3 and 3' can be very large without the inductances and resistances caused by the conductor length having an adverse affect on the later pulse generation. It is thus possible to arrange the portion of the electronic circuitry according to the invention lo cated to the right of the dividing line T shown in Figure 1 in the vicinity of the combustion engine or the autotransformer and to locate the direct-voltage source 1, which can, for example, be a battery and which supplies the circuitry with energy, at any desired place within a motor vehicle, for example. At the desired ignition time point, which, here, is determined by a further elec tronic engine control system (not shown), for example, which will not be further discussed here, the pilotable/triggerable switching element 5 is closed. This pi riggerable switching element 5 can in the simplest case be a common semico ctor component or other pilotable/triggerable switching element, such rrJ -15 as microelectromechanical switch or similar. By actuation of the switching ele ment 5 an electric circuit is closed between the charging capacitor 4 and the capacitor 7, so that the charge accumulated in the charging capacitor 4 is transmitted as a pulse through the primary coil 13 of the autotransformer to the capacitor 7. Due to the transmission ratio between the primary coil 13 and the secondary coil 14 of the autotransformer, the voltage pulse passing through the primary coil is transformed from some several hundred volts to a high voltage of several kilovolts, e.g. 30-50 kV, so that a spark arcs over the arc gap between the poles 15 and 16 of a spark plug in the combustion chamber of the combustion engine. Due to the connection between the primary coil 13 and the secondary coil 14 of the autotransformer 6 the voltage present at capacitor 7 is simultaneously transmitted to pole 15 of the arc gap so that this pole 15 is stepped up to sev eral hundred volts of potential compared to the grounded pole 16. This means that the energy continues to be supplied to the standing electric arc through the coil connection, the said energy being drawn from the energy source 1 or the capacitor 4 when switch 5 is in the closed condition. Opening of switch 5 is causes the capacitor 4 or the direct-voltage source 1 to be decoupled from the arc gap 15-16, so that further energy is now supplied from capacitor 7 until the charge in capacitor 7 has decreased to such an extent that the voltage has dropped below the arc voltage required for the arc gap. At this instant the electric arc extinguishes. At the same time, this means that, following the pulse-like charging process of the capacitor 7and the transmission of the charge from this capacitor to the electric arc an undefined residual voltage remains at capacitor 7 corresponding roughly to the lower limit of the arc voltage in the electric arc. Ordinarily, a volt age of some 200 to 300 volts will still be present in capacitor 7 after extinction of the electric arc. It follows that, to generate a good ignition spark the charging capacitor 4 must have a very much higher charge voltage, which should lie at around 600 and 1000 volts, compared to the residual voltage in capacitor 7 in

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-16 order to be able to generate an adequate ignition pulse with a suitable differen tial voltage of about 400 to 800 volts. The diode 24 connected in parallel to primary coil 13 of the transformer 6 pre vents, on the one hand, the occurrence of undesired oscillations, short-circuits the mutual inductance voltage and feeds the charge present at capacitor 7 to the secondary side once switching element 5 has opened. It is, of course, possible to arrange the pilotable/triggerable switching element 5 at any desired position in the charging circuit between the charging capacitor 4 and the capacitor 7. It is further possible, in a general manner, to operate the circuitry arrangement according to the invention with any desired polarities so that the pole 15 can be made to have either a positive or negative potential ver sus the grounding pole of the arc gap. If the polarity is changed, all that is nec essary is to ensure that the orientation of diode 24 is changed. It is also possi ble to arrange the connection between the primary coil 13 and the secondary coil 14 of the transformer at the lower end of the coils instead of at the upper end as shown in the figure. In the embodiment shown in Figure 1 B, the described circuitry is expanded such that the orientation of the capacitor 7 with its connecting poles 7a and 7b can be switched in the current flow direction of the shown circuitry. Due to this circuitry, it is possible to avoid having to first discharge the charged capacitor 7 in order to generate the next ignition spark, such discharge in any case only being possible, according to embodiment as shown in Figure 1A, down to a residual voltage. According to this embodiment, the charge accumulated at capacitor 7 can be utilized by switching the polarity of the capacitor 7 in the circuitry in order to in crease the difference in potential between the capacitors 4 and 7. When a pulse is generated, the charge of capacitor 4 is first transmitted through the primary coil 13 to capacitor 7 through closing of the switches 5a and 5b. Once the potential has been thus equalized, the voltage at capacitor 7 essen sponds to the voltage at capacitor 4.

-17 The necessity to discharge capacitor 7 for the next pulse generation, whereby, according to the above embodiment, an unavoidable residual voltage would remain, is eliminated here due to the fact that, by opening of the switches 5a and 5b, as well as the subsequent closing of the switches 5c and 5d, the ca pacitor 7 can be electrically turned around, i.e. its polarity reversed, within the circuitry. The sequence of capacitor poles 7a and 7b existing in the direction of current flow within the circuitry is thus reversed by this switchover, whereby the voltage differential between the capacitors 4 and 7 is increased. Prior to reversal of the capacitor 7, the two essentially equally positively charged poles 2' of the capacitor 4 and 7b of the capacitor 7 were connected. The same applies to the negatively charged poles 3' and 7a. After the reversal, however, the positive pole 2' is connected with the negative pole 7a, and the negative pole 3' with the positive pole 7b, which results in a summation of the essentially identical voltages present at the capacitors. Due to the now distinctly higher voltage differential between the capacitors 4 and 7, which in the ideal case is double the operating voltage at capacitor 4, there is a renewed potential equalization through pulse-like transfer of the charge between the capacitors, which in turn generates an ignition spark. The capacitor can thus be switched repeatedly for the generation of pulses. The circuitry arrangement for electrical reversal of the polarity of capacitor 7 can also be used in an embodiment as shown in Figure 1A. If the voltage at ca pacitor 4 then lies at about 300 V, for example, and there is a residual voltage of 200 V at the capacitor 7, the difference of 100 V may not be sufficient to gener ate an ignition spark. After reversal of the capacitor polarity, however, the differ ential voltage rises to 400 V, which constitutes a sufficient voltage. With this circuitry variant it is thus possible, provided it is used in an embodi ment as shown in Figure 1A, on the one hand to utilize the residual charge in capacitor 7 and on the other hand to reduce the operating voltage of the cir according to Figure 1 B, since the voltage differential between capacitors 4 -18 and 7 can be raised in the ideal case to double the value of the voltage present across capacitor 4. As a further extension to Figure 1 A, in the embodiment shown in Figure 1 B the ground definition can be switched via the switching element 17. This makes it possible to raise the air gap 15-16 in a targeted manner to the voltage of the direct-voltage source, which results in advantages that will be described using the similar embodiment as shown in Figure 2. Figure 1 C shows a circuitry variant in which both the charging capacitor 4 and the capacitor 7 within the circuitry can be reversed in polarity relative to the other capacitor in each case. This makes it possible, at the instant when a mutual inductance voltage occurs, due to decay of the magnetic field in the primary coil 13 after passage of the current/voltage maximum of the generated pulse, to switch all partial voltages at coil 13 and capacitors 4,7 in maximally additive series. This mutual inductance voltage, which was limited by a diode in the preceding embodiment, is thus utilized here for an alternative voltage pulsed operation of the device in resonance. The function principle of this circuitry arrangement is described in detail as fol lows: Assuming a situation in which both the capacitors 4 and 7 are charged to the same level, capacitor 7 is reversed by means of switch 5 corresponding to the preceding embodiment as shown in Figure 1 B. Due to the voltage differential thus created, charge flows from capacitor 4 to capacitor 7, whereby a cur rent/voltage pulse is generated in the primary coil 13 and whereby, furthermore, the polarity-reversed capacitor 7 is charged in the opposite direction so that its polarity once again corresponds to the starting situation. Due to the decaying magnetic field in primary coil 13 after the pulse maximum, a mutual inductance voltage is generated which changes the polarity at coil 13.

-19 At the instant at which the mutual induction voltage occurs, the capacitor 7 that has been charged in the opposite direction is switched over so that now, in the negative half-wave of the pulse, all voltages occurring at the capacitors and the primary coil are in additive series, which causes the capacitor 7 to be again charged in the opposite direction and its polarity to correspond once more to the starting situation. Once the maximum of the negative half-wave of the pulse has been reached, the decay of the magnetic field once more results in a mutual inductance volt age which changes the voltage conditions at the primary coil. This mutual in ductance voltage is now in maximal additive series with the voltage at capacitor 7, but not with the voltage at capacitor 4. In order now to cause all voltages present at the capacitors 4,7 and the coil 13 be in maximal additive series, capacitor 4 must be switched over. When this is done, charge is again transferred to capacitor 7, albeit this time in negated po larity versus the starting situation. The process of reversing the polarity of one of the two capacitors 4, 7 is thus repeated whenever the current/voltage pulse in the primary coil passes through its negative or positive maximum, upon which, due to the subsequent decay of the magnetic field, an induction voltage occurs at the coil which runs counter to the excitation voltage. The reversal must be designed such that, after reversal of one of the two ca pacitors, all partial voltages present at the capacitors and the coil maximally summate in order to draw a maximal energetic benefit from the circuitry and to permit resonance operation. Compared to the Figures 1, the circuitry arrangement according to the invention shown in Figure 2 differs in that the circuitry has one electric circuit each for charging and discharging of the capacitor 7. In the circuitry shown, both ca pacitor 7 and autotransformer 6 are arranged in each case in a electric circuit section forming part of both electric circuits. PALt 1 Arr O -20 This permits the charge to pulse through autotransformer 6 during both charg ing and discharging of capacitor 7. This ensures that during one full charging and discharging cycle of the capacitor 7 two ignition pulses can be generated, whereby the circuitry according to the invention differs from the known circui tries in which an ignition pulse could be generated merely in the discharging phase of the capacitor. Furthermore, it is also possible with the circuitry as shown in Figure 2 to continue to supply energy to the struck electric arc in two different ways. These can be either the continued supply of direct current or alternating current energy, whereby with the continued supply of alternating cur rent energy the required amount of energy can be advantageously adapted to the condition prevailing in the combustion chamber, which has a particularly positive effect when a lean mix is to be ignited or when turbulence occurs in the combustion chamber in the different load modes of the engine, cases in which, in the event of insufficient continued energy supply, the electric arc would be interrupted. The circuitry arrangement according to the invention as shown in Figure 2 can be utilized in several operating modes, realized in the manner that in each elec tric circuit, two switching elements are arranged, of which in the present exam ple one is pilotable/triggerable in each case. The charging electric circuit is now given in that, after closing of the pilo table/triggerable switching element 5, the charge of the capacitor 4 is transmit ted pulse-like via the primary coil 13 of the transformer 6 and the diode 9, as a non-pilotable switching element, to the capacitor 7. The discharge electric cir cuit, on the other hand, is given in that, after opening of the switch 5, the pilo table/triggerable switch 8 is closed, thus short-circuiting the charge of the ca pacitor pulse-like via the diode 10, the primary coil 13 and the closed switch 8. This being the case, it is possible with this circuitry to alternate the circuitry ac cording to the invention between pulse-like charging and discharging of the ca pacitor 7 by means of the pilotable/triggerable switching elements 5 and 8. The diodes 9 and 10 arranged in both the charging and the discharging electric cir ereby ensure that current always flows through the primary coil of trans form in the same direction.

-21 The various possible operating modes are described below. 1. By actuation of the pilotable/triggerable switch 17, which can be piloted, for example, by an electronic engine control system, the ground potential of the entire circuitry arrangement is defined. As a result, through the connection between the primary and secondary coil of the transformer 6, pole 15 of the arc gap is stepped up to a voltage of several hundred volts versus pole 16. After the pilotable/triggerable switch 5 closes, the charge of the capacitor 4 is transferred pulse-like to the capacitor 7 via the primary coil 13 in the di rection of the arrow 11, which is governed by the diode 9. Due to the pulse like charge passage through the primary coil 13, a transformed high voltage of several kilovolts is generated in the secondary coil 14, which causes a spark to arc over between pole 15 and 16 of the arc gap. This spark has a duration of approx. 100 to 300 psec. As already described in Figure 1, the constantly prevailing high voltage of several hundred volts between pole 15 and 16 of the arc gap ensures that energy can continue to be supplied to the electric arc, as long as this high voltage lies above the arc voltage of the electric arc. The electric arc can be made to extinguish as soon as the pilotable/triggerable switch 17 is opened and the definition of the ground potential is thus lost. This circuitry arrange ment thus offers the advantage that the spark duration of the electric arc can be variably adjusted and thus adapted to the engine conditions. The generated spark head current can be very high, while the spark tail current depends on the applied direct voltage and the interference suppression re sistors as well as any series spark paths in any installed ignition spark dis tributors. 2. Once the electric arc has extinguished it can be re-struck by renewed closing of switch 17 and simultaneous closing of switch 8. The charge at the ca pacitor 7 is then short-circuited by diode 10 such that it pulses in direction 11 through the primary winding of the transformer 6, so that a high-voltage pulse of several kilovolts (30-60 kV) is generated on the secondary side in c il 14, which causes a breakdown in the gas mix between the poles 15 and Pilt 16 of the arc gap of a spark plug. Energy continues to be supplied to the electric arc for as long as switch 17 remains closed. Using the circuitry according to the invention it is therefore possible to gen erate an ignition spark in both the charging and discharging process of the capacitor 7, in order to achieve an increase in the engine speed. Unlike the known circuitry arrangements, the circuitry arrangement accord ing to the invention furthermore permits variation of the electric arc duration by actuating the pilotable/triggerable switching element 17. 3. The direct current energy supplied which is made possible by actuation of switch 17, may not be considered sufficient in those cases where the arc voltage of the electric arc fluctuates strongly in lean mixes or in the event of strong turbulence in the combustion chamber, as a result of which the direct voltage present between the poles 15 and 16 of the arc gap may not be sufficient to maintain the electric arc. High current intensities are conse quently also required in the spark tail. In this case it is possible, once the switch 17 and the switch 5 have closed, to generate an ignition spark first in the charging process of the capacitor 7 and subsequently, with an ignited and standing electric arc to alternate be tween discharging and charging of the capacitor by multiple alternate switching of the switches 5 and 8, whereby a voltage pulse is transformed every time, through which energy continues to be supplied to the standing electric arc. This principle is shown in Figure 3. At the ignition time point T1, the charge transfer from capacitor 4 to capacitor 7 via the primary coil 13 and the diode 9 causes the voltage at capacitor 7 to rise from UO to U2. This voltage pulse is capable of igniting the mix in the sparking gap between the poles 15 and 16 by means of an ignition spark 12. The capacitor 7 is then short-circuited into the standing electric arc through switchover into the discharging process due to opening of the switch 5 and closing of the switch 8, so that the charge again flows in direction 11 via the diode 10 and the primary coil 13, until a voltage U1 ne d at the capacitor 7. This voltage pulse, which corresponds to the dif- -23 ference between U1 and U2, is also stepped up due to the transmission ratio between primary coil 13 and secondary coil 14, so that energy can be supplied to the standing electric arc. Following this, switch 8 is opened again and switch 5 closed, so that the capacitor 7 is again charged to voltage level U2. This al ternating cycle is repeated for as long as energy is to be supplied to the stand ing electric arc. It is especially advantageous in this respect that the amount of supplied energy is variable and can thus be adapted to the engine conditions. This variability is given by the fact that the voltage difference between the volt age levels U1 and U2 is adjustable. The difference is mainly determined by the duration of switchover between actuation of the switch 5 and the switch 8, since the charging and discharging time constants are predetermined in the circuitry. Towards the end of the energy supply phase, when the electric arc is to be switched off, the capacitor 7 can either be completely charged or completely discharged. In order to allow the electric arc to be extinguished in a defined manner, however, the switch 17 is opened. In the time diagram shown in Figure 3, the total spark duration of the electric arc is given in a time span from T1 to T2, where, after ignition of the electric arc, there is multiple alternation between a voltage level U1 and U2 in the charging and discharging process of the capacitor 7. Toward the end of the spark dura tion the capacitor 7 is completely charged at time T2 in the present example, so that in the next ignition cycle the charge that has accumulated at the capacitor can be used to strike the electric arc once again. Following this, it is again pos sible, through alternating switching of the pilotable/triggerable switching ele ments 5 and 8 to supply more energy to the standing electric arc. The alternat ing switching can, for example, be controlled by a software of an electronic en gine control system with or without sensor monitoring, even during operation. Compared to Figure 2, Figure 4 differs in that the diodes 9 and 10 defining the direction of current flow are now replaced by pilotable/triggerable switching elements 20 and 19. Thus, for a charging process of the capacitor 7, after clos ing of switch 17, in order to define the ground potential, first switch 5 and then Ca is closed, and, after the discharging process of the capacitor 7, the (( 'Iatter-n ed switches are opened and switches 8 and 19 closed again.

-24 With the circuitry shown in Figure 4 is possible, just as with the circuitry ac cording to Figure 2, through alternating switching between the switches 5 and 20 as well as 8 and 19, to continue to supply energy to a struck electric arc or, after intermediate opening of the switch 17 to generate an ignition spark during both the charging and the discharging process of capacitor 7. Figure 5 is further developed compared with Figure 4 in that the secondary side of the transformer 6 is equipped with two secondary coils 14 and 18. At each of these secondary coils an arc gap between the poles 15 and 16 resp. 15' and 16' is connected, whereby these can be, for example, two spark plugs in the com bustion chamber of a cylinder. As a result, it is possible, by increasing the igni tion spark number to achieve a better ignition of the gas mix. It is, of course possible, to arrange still further coils and spark plugs on the secondary side. However, care should be taken to design the entire circuitry arrangement to have such a high power that sufficient energy can be supplied in each ignition spark. Figure 6 shows an alternative embodiment to the circuitry arrangement accord ing to Figure 2, where a rectifier arrangement, consisting of the diodes 9, 10, 22 and 23, is arranged in series with capacitor 7, between the direct-voltage tap ping points of which rectifier is arranged an autotransformer 6 consisting of the primary coils 13 and the secondary coil 14. The electric circuit for pulse-like charging of the capacitor 7 is only given when the pilotable/triggerable switch 5 is closed and the pilotable/triggerable switch 8 is opened so that the charge is transferred to capacitor 7 via the diode 9, the primary coil 13 and the diode 22. For initiation of the charging process, switch 5 is opened and switch 8 closed, so that the charge of the capacitor flows away via the diode 10, the primary coil 13 and the diode 23. Depending on the piloting of the switches 5 and 8, a new ignition spark can be generated during charging and discharging in either case, or energy can be fed into a standing electric arc. Figure 7 shows an arrangement equivalent to that of Figure 6, excepting only that the pulse-operated device, instead of the autotransformer a laser diode ins between the direct-voltage tapping points of the rectifier arrange- -25 ment. As a result, it is possible, by alternating switching of the switches 5 and 8, to operate the laser diode 6' in pulsed mode. Alternative to laser diode 6', the pulse-operated device can also be any other light-emitting element. In a further alternative embodiment, also corresponding to Figure 7, it is possible to develop the rectifying diodes as laser diodes 22', 23', 10' and 9'. In this case it is possi ble to connect to the circuitry arrangement a laser diode array consisting, for example, of five diodes appropriately connected to one another. It is also possi ble, depending on the specific application, to use laser diodes operating in dif ferent spectral ranges in the charging and discharging circuit. Figure 8 shows an embodiment of the circuitry according to the invention in which a pulse-operated device 6 is located both in the charging circuit and a further 6" in the discharging circuit. Furthermore, in the circuitry arrangement, not only one energy accumulator, but two energy accumulators are used, given by the capacitors 7 and 21. The capacitor 21 in this case can be alternately se quenced by the pilotable/triggerable switching element 5'. The capacity of the overall capacitor arrangement is increased due to the parallel connection of the capacitors 7 and 21. Depending on the operating voltage of the pulse operated device, capacitors can be used as energy accumulators that have capacities of up to several thou sand Farad, such as Gold-Cup capacitors. The device shown in Figure 8 can in particular be used when a reluctance mo tor is to be piloted in which current is to flow pulse-like through the excitation coils 6 and 6" one after the other. In the example according to Figure 8, the capacitor 7 is charged with the charge of the capacitor 4 when the pilotable/triggerable switching element 5 is closed. In this case, the charge flows pulse-like through coil 6. After closing of the switch 5' it is possible to send another charge pulse through coil 6. Alternatively, it is also possible, as early as the first charging process, to keep switch 5' closed so that the overall capacity will rise accordingly.

-26 After the charging process, switch 5 is opened and switch 8 closed, so that, upon discharging of the capacitor 7 resp. capacitors 7 and 21, the flow passes through coil 6" of the reluctance motor. By using two capacitors 7 and 21, whereby the capacitor 21 can alternatively be switch in parallel to capacitor 7 via switching element 5', it is possible to realize various pulse conditions, since the changed capacities also affect the magni tude of the pulses. Figure 9 shows a circuitry arrangement in which two circuitries according to the invention are used, whereby the lower circuitry B serves to generate an ignition spark in the arc gap between the poles 15 and 16, and the upper circuitry A is intended to pulse-pilot a laser diode 6', the pulsating emitted light of which radi ates into the arc gap. By appropriate selection of the laser diodes it is thus pos sible to emit a light wavelength which will pre-ionize a gas mix located between the poles 15 and 16 of the arc gap. This pre-ionization can be increased when the light of the laser diode is focussed by means of a lens in the arc gap. Even if no pre-ionization of the gas mix is generated or desired, it is still possible to ex cite the gas molecules with the help of the laser light pulse so that a lower over all ignition voltage will be required to ignite the gas mix, which results in im proved combustion. For excitation or pre-ionization of the gas mix it is advanta geous if a laser diode with as short a light wavelength as possible is used. The circuitries shows in Figure 9 correspond, in the case of the upper circuitry A to the already discussed circuitry of Figure 2, where merely the piloted trans former 6 has been replaced by a laser diode 6' which is connected in series with a current-limiting resistor R. The circuitry arrangement B corresponds to the circuitry already shown in Figure 4. The circuitries A and B shown in the example of Figure 9 are synchronized with each other by means of an electronic motor control system (not shown). It should be mentioned once again, in general terms, that all pilo table/triggerable elements, in particular the elements 5, 8, 17, 19, and 20 of the s discussed can be piloted by means of current, voltage, inductively, capac ely, magnetically or optically. Thus, all known switch elements, such -27 as semiconductor elements, integrated circuits and other conductive and switchable components can be employed. It is also possible to use microelec tromechanical switches (MEMS technology).

Claims (41)

1. Electronic circuitry for generation of current/voltage pulses with - a direct-voltage source (1), - at least one charging energy accumulator (4) connected to the poles (2,3) of the direct-voltage source (1) - at least one pilotable/triggerable switching element (5) - and at least one device (6) operated with the generated pulses c h a r a c t e r i z e d i n t h a t it has at least one further energy accumulator (7) connected in series with at least one switching element (5) and the pulse-operated device (6) and thus connectable via at least one switching element to the poles (2,3) of the charging energy accumulator (4), whereby electric power can be supplied in the charging/discharging process of at least one of the further energy accumulators (7) to the device (6).

2. Circuitry according to Claim 1, characterized i n t h a t , within the circuitry the polarity of one or several energy accumulators (4,7) is reversible.

3. Circuitry according to Claim 2, characterized i n t h a t , within the electric circuit of the circuitry the given se quence of connection poles of one or several of the energy accu mulators (4,7) in the direction of current flow is reversible. -2

4. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t , an energy accumulator (4,7) comprises an arrangement of several accumulator elements.

5. Circuitry according to Claim 4, characterized i n t h a t the arrangement is connected in series and/or parallel.

6. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the circuitry has one electric circuit in each case to charge and discharge each energy accumulator (7,21).

7. Circuitry according to any of the preceding claims, characterized i n t h a t each energy accumulator (7,21) is arranged in a section of an electrical circuit which forms part of both electrical circuits

8. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the energy accumulators (4,7,21) and/or accumulator elements are developed as capacitors

9. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t a pulse-operated device (6) is ar ranged in a section of an electric circuit which forms part of both electrical circuits.

10. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t one pulse-operated device (6) is located in the charging circuit and one (6") in the discharging cir cuit.

11. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t each electric circuit has at least one (5 resp. 8), preferentially two switching elements (5,9 resp. 8,10). -3

12. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the switching elements (5,9,19,20) are pilotable/triggerable.

13. Circuitry according to Claim 12, characterized i n t h a t the circuitry can be alternated between pulse-like charging and discharging of each energy accumulator (7,21) by means of the pilotable/triggerable switching elements (5,8,19,20).

14. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t current flows through the pulse operated device (6) in the same direction (11) during charging and discharging of the energy accumulator (7).

15. Circuitry according to Claim 14, characterized i n t h a t the path of the charge flow in each electric circuit is de fined by diodes (9,10,22,23).

16. Circuitry according to Claim 15, characterized i n t h a t a rectifier arrangement (9,10,22,23), between the direct voltage tapping points of which is arranged a pulse-operated de vice (6), is connected in series with an energy accumulator (7).

17. Circuitry according to either Claim 15 or 16, c h a r a c t e r i z e d i n t h a t the diodes are laser diodes (9',10',22',23').

18. Circuitry according to Claim 14, characterized i n t h a t the path of the charging flow in each electric circuit is de fined by pilotable/triggerable switching elements (5,8,19,20).

19. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the device operated with the pulses is a transformer (6).

20. Circuitry according to Claim 19, characterized i n t h a t with the transformer (6) high-voltage pulses can be gener ated for the striking of an electric arc (12) or for the sparking of fluorescent/neon tubes.

21. Circuitry according to Claim 20, characterized i n t h a t direct and/or alternating current energy can continue to be fed into the standing electric arc (12)

22. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the transformer (6) is an auto transformer with a connection between primary (13) and secon dary coil (14).

23. Circuitry according to Claim 22, characterized i n t h a t the free end of the secondary coil (14) leads to one pole (15) of an arc gap (15-16), preferentially a spark plug, the other pole (16) of which is connected to frame potential.

24. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the grounding conductor of the energy source (1) is disconnectable from the vehicle ground by means of a pilotable/triggerable switching element (17).

25. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the transformer (6) has several, preferentially two secondary coils (14,18).

26. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t a switching element (24) blocking the charging current of an energy accumulator (7,21) is connected in parallel to the primary coil (13) of the transformer (6) and/or to the charging energy accumulator (4). -5

27. Circuitry according to Claim 26, characterized i n t h a t the switching element is a diode.

28. Circuitry according to Claim 26 or 27, c h a r a c t e r i z e d i n t h a t the blocking switching element (24) is a pilo table/triggerable switching element.

29. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the pilotable/triggerable switching elements (5,8,17,19,20) can be piloted by current, voltage, induc tively, capacitatively, magnetically or optically.

30. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the pulse-operated device (6) is a light emitting element (6').

31. Circuitry according to Claim 30, characterized i n t h a t the light emitting element is a laser diode (6').

32. Circuitry according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the pulse-operated device (6) is a reluctance motor (6,6").

33. Method for generation of current/voltage pulses in an electronic circuitry according to any of the preceding claims for the piloting of a pulse-operated device (6,6',6") c h a r a c t e r i z e d i n t h a t the pulses are generated after piloting of at least one switching element (5) by pulse-like transfer of electric charge from at least one charging energy accumulator (4) through the device (6,6',6") to at least one other energy accumulator (7).

34. Method according to Claim 33, characterized i n t h a t to increase the difference in potential between at least two energy accumulators (4,7), the polarity of one of the energy accu mulators (4,7) is reversed relative to the other energy accumula tor(s) (7,4) -6

35. Method according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t upon the occurrence of a mutual in ductance voltage in a pulse-operated device with an inductance at least one of the energy accumulators (4,7) is alternated in such a way that all voltages present in the device (6) and the energy ac cumulators (4,7) are in maximal additive series.

36. Method according to any of the preceding claims c h a r a c t e r i z e d i n t h a t the electrical charge flows pulse-like through the pulse-operated device (6) in the same direction (11) during both charging and discharging of the energy accumulators (7, 21).

37. Method according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t the energy accumulators are devel oped as capacitors.

38. Method according to any of the preceding claims for generation of a high-voltage ignition spark for an ignition system of a combustion engine c h a r a c t e r i z e d i n t h a t energy continues to be fed to the standing electric arc (12).

39. Method according to Claim 38, characterized i n t h a t energy is fed into the electric arc (12) by alternating switching between charging (U 2 ) and discharging (U 1 ) of an energy accumulator (7) before the charging (UL) resp. discharging (Uo) limit has been reached.

40. Method according to either Claim 38 or 39, c h a r a c t e r i z e d i n t h a t the energy supplied is adapted to the elec tric arc conditions. -I

41. Method according to any of the preceding claims, c h a r a c t e r i z e d i n t h a t a circuitry (B) for generation of an ig nition spark (12) and a circuitry (a) for piloting of a laser diode (6') is used, the light (L) of which radiates through the ignition spark gap (15-16).