Classifications

• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P9/00—Electric spark ignition control, not otherwise provided for
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P9/00—Electric spark ignition control, not otherwise provided for
  • F02P9/002—Control of spark intensity, intensifying, lengthening, suppression
  • F02P9/007—Control of spark intensity, intensifying, lengthening, suppression by supplementary electrical discharge in the pre-ionised electrode interspace of the sparking plug, e.g. plasma jet ignition
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P23/00—Other ignition
  • F02P23/04—Other physical ignition means, e.g. using laser rays
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P17/00—Testing of ignition installations, e.g. in combination with adjusting; Testing of ignition timing in compression-ignition engines
  • F02P17/12—Testing characteristics of the spark, ignition voltage or current
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P17/00—Testing of ignition installations, e.g. in combination with adjusting; Testing of ignition timing in compression-ignition engines
  • F02P17/12—Testing characteristics of the spark, ignition voltage or current
  • F02P2017/121—Testing characteristics of the spark, ignition voltage or current by measuring spark voltage
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P23/00—Other ignition
  • F02P23/04—Other physical ignition means, e.g. using laser rays
  • F02P23/045—Other physical ignition means, e.g. using laser rays using electromagnetic microwaves
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
  • F02P3/00—Other installations
  • F02P3/01—Electric spark ignition installations without subsequent energy storage, i.e. energy supplied by an electrical oscillator

Definitions

• the present invention relates to controlling the power supply of a plasma generation resonator, in particular in a plasma automotive ignition application by radio-frequency biasing of the resonator of a multi-spark plug.
• the BME multi-spark plug has a significant innovation and a different geometry from conventional spark plugs.
• Such a BME is described in detail in the following patent applications in the name of the applicant FR 03-10766, FR 03-10767, FR 03-10768, FR 04-12153 and FR 05-00777.
• a BME includes a resonator whose resonant frequency F c is located in the high frequencies, typically between 4 and 6 MHz, to supply the candle with a resonance amplified voltage.
• branched sparks These are referred to as branched sparks, insofar as they involve the simultaneous generation of at least several lines or ionization paths in a given volume, their branches being moreover omnidirectional.
• the control of the power supply of such a BME requires the use of a high voltage generator whose operating frequency is very close to the resonance frequency of the radio frequency resonator. The greater the difference between the resonance frequency of the resonator and the operating frequency of the generator, the higher the resonator overvoltage coefficient (ratio between the amplitude of its output voltage and its input voltage) is high.
• Such a voltage generator consists mainly in using a control frequency of the resonator as close as possible to the resonance frequency of the resonator, in order to benefit from a higher overvoltage coefficient. high possible.
• the subject of the invention is a method for controlling a radiofrequency plasma generator, comprising: a supply circuit, having a switch controlled by a control signal in the form of at least one train of control pulses applying an intermediate voltage to an output of the supply circuit at the frequency defined by the control signal; - a resonator connected to the output of the supply circuit and able to generate a spark between two electrodes when a high voltage level is applied to the output of the supply circuit, said method being characterized in that it comprises: - the reception of first measurement signals representative of the operation of a combustion engine, the reception of seconds electrical measurement signals representative of the type of spark generated, and - the real-time regulation, as a function of the first and second measurement signals received, from least one parameter taken from at least the intermediate voltage level, the control frequency, the duration of the control pulse train,
• the method comprises the joint regulation of the level of the intermediate voltage and the duration of the control pulse train.
• the control signal being generated in the form of a plurality of pulse trains of control, the regulation concerns the number of said trains and the inter-train time.
• the method comprises the memorization of relations between measurement signals and the value of parameters to be regulated, the regulation consisting of determining and applying the value of at least the parameter to be regulated according to the measurement signals received and the memorized relationships. .
• the first measurement signals are selected from the group consisting of engine oil temperature, engine coolant temperature, engine torque, engine speed, ignition angle, air temperature. intake pressure, manifold pressure, atmospheric pressure, combustion chamber pressure or maximum pressure angle.
• the second measurement signals comprise at least one measurement of the voltage at the terminals of a storage capacitor supplying the intermediate voltage at the input of the resonator and / or at least one measurement of the current in the resonator.
• a first measurement of the voltage at the terminals of the storage capacitor before or at the beginning of the control pulse train is carried out and a second measurement of the said voltage after or at the end of the pulse train of ordered.
• a plurality of measurements are carried out during the duration of the control pulse train.
• the method comprises regulating the control frequency to a set point substantially equal to the resonance frequency of the resonator.
• the invention also relates to a radiofrequency plasma generating device comprising: - a power supply circuit having a switch controlled by a control signal in the form of at least one control pulse train, the switch applying a voltage intermediate on an output of the power supply circuit at the frequency defined by the control signal,
• a resonator connected to the output of the supply circuit and capable of generating a spark between two electrodes when a high voltage level is applied to the output of the supply circuit, said device being characterized in that it comprises a control module adapted to implement the method according to any one of the preceding claims.
• FIG. 1 illustrates an embodiment of a plasma generating device
• FIG. 2 illustrates an electric model used for the resonator
• FIG. 3 illustrates a schematic diagram of the radio frequency ignition
• FIG. 4 illustrates a device for generating the intermediate voltage involved in ignition radio frequency integrating a control module according to the invention.
• a plasma generating device mainly comprises three functional subassemblies:
• a power supply 2 designed to resonate an L-C structure at a frequency greater than 1MHz with a voltage across the capacitor greater than 5kV, preferably greater than 6kV; a resonator 6, connected at the output of the supply circuit, having an overvoltage factor greater than 40 and a resonance frequency greater than 1 MHz; a candle head 110, comprising two electrodes 103 and 106 separated by an insulator 100, for generating a branched plasma when radiofrequency excitation is applied across its electrodes.
• the supply circuit 2 advantageously comprises:
• a low voltage supply 3 (generating a DC voltage of less than 1000 V);
• radio frequency amplifier 5 amplifying the DC voltage and generating an AC voltage at the frequency controlled by the switching control 4.
• the resonator LC is applied on the resonator LC 6.
• the resonator LC is applied on the resonator LC 6.
• the power supply 3 applies the AC voltage between the electrodes 103 and 106 of the candle head.
• the voltage supplied by the power supply 3 is less than 1000V and the power supply preferably has a limited power. We can thus foresee that the energy applied between the electrodes is limited to 30OmJ by ignition, for safety reasons. This also clamps the intensity in the voltage generator 2 and its power consumption.
• the power supply 3 may include a 12-volt converter to Y Volt, where Y is the voltage supplied by the power supply to the amplifier. It is thus possible to generate the desired DC voltage level from a battery voltage.
• the stability of the DC voltage generated is not a priori a decisive criterion, it can be expected to use a switching power supply to power the amplifier, for its qualities of robustness and simplicity.
• the supply circuit 2 makes it possible to concentrate the highest voltages on the resonator 6.
• the amplifier 5 thus deals with much lower voltages than the voltages applied between the electrodes of the candle.
• the amplifier 5 accumulates energy in the resonator 6 at each alternation of its voltage.
• a class E amplifier 5 will preferably be used, as detailed in US Pat. No. 5,187,580. Such an amplifier makes it possible to maximize the overvoltage factor.
• Those skilled in the art will of course associate a switching device adapted to the chosen amplifier, to support the requirements of voltage increases and to have an adequate switching speed.
• FIG. 2 illustrates an electric model of the resonator 6.
• the series inductance 65 has in series an inductance Ls and a resistor Rs taking into account the skin effect in the radiofrequency domain.
• the capacitor 119 has in parallel capacitance Cs and resistor Rp. Ignition electrodes 106 and 103 are connected across capacitor Cs.
• the resistance Rp is added to model the discharge and corresponds where appropriate to the dissipation in the ceramic candle.
• the plasma generating device which has been described may comprise a plasma generation resonator adapted to achieve a combustion engine controlled ignition, an ignition in a particle filter, or a decontamination ignition in an air conditioning system.
• FIG. 3 illustrates a basic diagram of the radiofrequency ignition according to an embodiment of an amplifier 5, having a power MOSFET transistor as a switch controlling the commutations across the resonator 6.
• a control signal generator 8 applies a control signal Vl to a control frequency on the gate of a power MOSFET 9, via an amplification device 10 shown schematically.
• the latter is not permanent but is present in the form of control pulse trains at the control frequency.
• a parallel resonant circuit 62 is connected between an intermediate voltage source Vinter and the drain of the transistor 9.
• This circuit 62 comprises an inductance Lp in parallel with a capacitance Cp.
• the parallel resonator transforms the intermediate voltage Vinter into an amplified voltage Va, which is supplied on the drain of the transistor 9 connected to the input of the resonator 6.
• the transistor 9 therefore acts as a switch and transmits (respectively blocks) the voltage Va at the input of the resonator 6 when the control signal Vl is in the high logic state (respectively low).
• the intermediate voltage Vinter supplied at the input of the parallel resonant circuit 62, is typically generated by means of a voltage booster, shown schematically in FIG. 4.
• the voltage booster circuit is for example supplied from a battery voltage Vbat and is composed of a Lboost inductor, a MOSFET K, which serves as a switch controlled by a control module 20, a diode Dboost, and a Cboost capacitor.
• the control module delivers a control signal V2 in the form of high frequency pulse train, so that switch K is periodically made conductive.
• K When K is closed, the Lboost inductor loads with the voltage Vbat at its terminals.
• the Dboost diode drives and the energy stored in the inductor causes a current to flow to the output and the capacitor Cboost to charge it.
• the Cboost storage capacity is loaded in this way until the desired value of Vinter is reached.
• a regulation loop not shown, measures the value of the voltage across the capacitor Cboost at any time and controls the control module to stop the output voltage rise when the desired value is reached. The voltage rise process is inhibited in all cases at the beginning and during the ignition control train.
• the invention provides for acting on a certain number of operating parameters of the system, or on at least one of them, in order to limit as much as possible the bridging phenomenon during the discharge of the spark plug, in particular: the supply voltage of the resonator provided for applying the high voltage across the electrodes, the excitation frequency of the resonator, the duration of the control train, the possibility of achieving several trains and their number, as well as the time between the trains.
• These parameters can be advantageously adjustable during the operating time of the system and their adjustment in real time, as will be explained in more detail later, must make it possible to obtain an optimal branching of the discharge by limiting the occurrence of the bypasses.
• the applied voltage setpoint must be such that it allows the system to be placed under optimal conditions from the point of view of combustion, namely a branching of the maximum volume spark for a voltage amplitude applied across the electrodes just below the high voltage limit from which bridging occurs.
• the real-time regulation of the intermediate voltage value to be carried out at the terminals of Cboost takes into account measurement signals of operating parameters of the combustion engine.
• the real-time regulation of the optimum intermediate voltage value to be achieved at the terminals of the Cboost capacitor can be refined by also taking into account electrical measurement signals of the resonator 6 power supply, representative of the type of spark. realized.
• the regulation process determines the value of the setpoint of the voltage to be achieved before lighting at the terminals of Cboost, as a function of the relationships stored between these measurement signals and the voltage value to be applied across Cboost.
• Such a real-time control of the intermediate voltage across Cboost before ignition is achieved via the control module 20.
• the latter thus comprises an interface 21 for receiving signals for measuring operating parameters of the combustion engine.
• Engine operating parameters measured include engine oil temperature, engine coolant temperature, engine torque, engine speed, ignition angle, intake air temperature. pressure at the manifold, atmospheric pressure, pressure in the combustion chamber, maximum pressure angle or any characteristic quantity of engine operation. These types of measurement can be carried out in a manner known per se by those skilled in the art.
• control module 20 also comprises an interface 22 for receiving electrical measurement signals, representative of the type of spark generated.
• the control module 20 comprises a memory module
• the memory module 26 in which are stored relations between the measurement signals and the voltage value to be achieved across the Cboost capacity before ignition. These relationships can be established based on tests prerequisites.
• the memory module 26 can memorize the relations in the form of a function associating predetermined measurement signals with a single voltage setpoint to be achieved. For example, a linear function or a polynomial function can be extrapolated according to the results of prior tests on a resonator by varying the different parameters taken into account.
• the memory module can also store the relationships as a multidimensional array having as input measurement signals.
• the control module 20 comprises a module 25 determining the voltage setpoint to be made as a function of the measurement signals received and the relationships stored in the memory 26.
• the setpoint is supplied by the module 25 to a module 27, applying a control signal V2 on an output interface 24 adapted to control the process of voltage rise as explained above until the voltage value across the capacitance Cboost reaches the setpoint.
• the module 27 is for example a clock generator suitably chosen by those skilled in the art.
• a programming interface 23 can be provided for receiving and executing commands for modifying the relationships or parameters stored in the memory module 26.
• the programming interface 23 can in particular be a wireless communication interface. Thus, one can consider updating the relationships stored in the module 26 to optimize the operation of the ignition system after delivery.
• the reception interface 22 preferably receives one or more measurements of the value of the intermediate voltage across the storage capacitor Cboost and / or one or more measurements of the current entering the resonator 6 and this, during the duration of (or) the train (s) of control pulses Vl controlling the generation of 'spark.
• the current entering the resonator As for the current entering the resonator, it is an image of the high voltage across the electrodes of the resonator.
• This modulated signal at the resonant frequency (typically 5MHz) has a characteristic envelope of the branched discharge and bridging phenomena.
• the analysis of the envelope of the current signal during the duration of an ignition control requires the use of a device of the type of peak detector, known per se, which only outputs the peak values of the modulated sinusoid of the current signal.
• a first mode it is possible to consider the taking into account of a single measurement characteristic of the type generated spark, performed at the most representative instant of the development of the spark, either after or at the end of the spark generation control train. If the measurement chosen is the measurement of the current in the resonator, it is then possible to determine a threshold value Ml, such that: if the measurement carried out at the end of the control train is less than this threshold value, it is deduced that it a bypass is produced; if the measurement made is greater than this threshold value, it can be deduced that no bridging has occurred.
• a threshold value M2 for which: if the measurement carried out at the end of the control train implies a consumed energy lower than this threshold value, it is deduced that a bridging has occurred (which in fact decreases the value of energy transmitted to the resonator); if the measurement carried out implies a consumed energy higher than this threshold value, it is deduced that no bridging has occurred.
• a regulation based, as has just been explained, on a single measurement (of the current in the resonator or of the voltage on the storage capacity) per control train, preferably carried out at the end of the control train, is not robust enough.
• the measurement made is not only representative of the type of spark produced, but also of the frequency agreement between the supply circuit and the resonator, the fouling of the spark plug and other phenomena independent of the spark development.
• it is preferably carried out multiple electrical measurements during and / or before and / or after the control train.
• the analysis of the evolution of these multiple measurements makes it possible to extract more easily relevant parameters for the qualification of the development of the spark and thus to realize a regulation, in particular of the value of the intermediate voltage to be realized at the terminals of Cboost before ignition, more efficient.
• the measurement of the evolution of the voltage at the terminals of Cboost during and / or before and / or after the duration of the control train is a carrier of numerous information about the branching of the spark.
• the energy consumption of the resonator results in a voltage drop across the Cboost capacity, which can be followed. It is noted that an optimal branching of the generated spark is very energy consuming while the bridging phase greatly limits the consumption.
• the analysis of the voltage drop slopes at the terminals of Cboost thus makes it possible to detect the bridging and its instant of appearance.
• the analysis of the occurrence of the bridging may be based on the analysis of the input current envelope of the resonator.
• the regulation evoked so far to promote an optimal branching of the spark while avoiding the bridging phenomenon as much as possible acts preferably on the value of the intermediate voltage to be produced at the terminals of the Cboost storage capacitor for each ignition.
• the regulation process thus makes it possible to define a voltage setpoint to be reached at the beginning of each ignition, depending on the one hand, measuring signals representative of the operation of the engine and, on the other hand, electrical measurement signals representative of the type of spark generated.
• other control parameters of the system can also be taken into account in the real-time control process and thus be adjusted during the operating time of the system, in the same manner as explained above with reference to the control of the system. value of the intermediate voltage across Cboost for each ignition.
• the other operating parameters of the system involved in the development of the spark and likely to be modified during operation to adjust the system in real time are the resonator control frequency, the duration of the control pulse train. spark generation, or alternatively consisting of making multi-ignitions, the number of such control trains and the spacing between each train.
• the regulation according to the invention relates jointly the value of the intermediate voltage across Cboost for each ignition and the duration of the control pulse train Vl, controlling the generation of the spark.
• control module 20 is also used to generate the ignition control pulse train V1, the duration of which is then adjusted according to the measurement signals received and the memorized relationships. .
• the bridging phenomenon occurring during the train command and, generally, starting occur at the end of the control train it can be avoided by shortening the duration of the control pulse train so as to stop it just before the bypass (or just after the desired effect on the control train). combustion).
• this technique of limiting the bridging probabilities by reducing the duration of the ignition control train can be considered in conjunction with the technique of regulating the supply voltage of the resonator.
• regulating the supply voltage of the resonator consisting in defining a reduced level of intermediate voltage across the Cboost capacitor before ignition, advantageously makes it possible to push the bridging phenomenon as far as possible from the start of the control train. .
• control the resonator during ignition by means of a control signal in the form of a plurality of control pulse trains, each train having a very short duration, for example of order of 5 to 10 ⁇ s, so that no bridging has time to occur.
• a control signal in the form of a plurality of control pulse trains, each train having a very short duration, for example of order of 5 to 10 ⁇ s, so that no bridging has time to occur.
• the spacing between the different pulse trains of the control signal can be regulated in the direction of an increase. The ignition time is however increased, which may be unfavorable to the conditions of initiation of the mixture.
• the frequency of the resonator control signal is preferably chosen from the order of magnitude of the resonance frequency of the resonator 6. Indeed, the match between the resonance frequency of the resonator and the resonator frequency at which this is controlled (ie the frequency of the control signal), determines the ratio between the voltage amplitude at the input and the output of the resonator.
• the resonator efficiency is favored, insofar as its overvoltage coefficient Q is then the highest possible.
• the value of the control frequency can also be subject to the anti-bridging regulation as explained above, by determining an optimum value of control frequency shifted with respect to the resonant frequency, as a function of the received measurements. (motor and electric operation).
• This parameter can be regulated alone, or together with the value of the intermediate voltage, the duration of the control train, or even together with the latter two parameters.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Physics & Mathematics (AREA)
• Plasma & Fusion (AREA)
• Optics & Photonics (AREA)
• Ignition Installations For Internal Combustion Engines (AREA)
• Developing Agents For Electrophotography (AREA)

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• 2007
  • 2007-03-01 FR FR0701498A patent/FR2913297B1/fr not_active Expired - Fee Related
• 2008
  • 2008-02-13 US US12/529,348 patent/US8342147B2/en not_active Expired - Fee Related
  • 2008-02-13 DE DE602008002326T patent/DE602008002326D1/de active Active
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