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
  • 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
  • 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
  • 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
  • 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
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D2400/00—Control systems adapted for specific engine types; Special features of engine control systems not otherwise provided for; Power supply, connectors or cabling for engine control systems
  • F02D2400/22—Connectors or cables specially adapted for engine management applications
• • 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

Definitions

• the present invention relates generally to systems for generating plasma between two electrodes of a spark plug, used in particular for radiofrequency ignition control of a gaseous mixture in combustion chambers of an internal combustion engine.
• plasma generation circuits incorporating coils-candles are used to generate multi-filament discharges between their electrodes, to initiate the combustion of the mixture in the chambers of combustion of the engine.
• the multi-spark plug is described in detail in the following patent applications filed in the name of the applicant FR 03-10766, FR 03-10767 and FR 03-10768.
• Such a coil-plug is conventionally modeled by a resonator 1, whose resonant frequency F c is greater than 1 MHz, typically close to 5 MHz.
• the resonator comprises in series a resistor R, an inductance L and a capacitance C. Ignition electrodes 10 and 12 of the coil-plug are connected across the capacitor C.
• the resonator When the resonator is powered by a high voltage at its resonant frequency f c (1 / (2 ⁇ y / L * C), the amplitude across the capacitor C is amplified, making it possible to develop multi-filament discharges between the capacitors.
• candle electrodes over distances of the order of one centimeter, at high pressure and for peak voltages below 20 kV. These are called branched sparks, insofar as they involve the simultaneous generation of at least several lines or ionization path in a given volume, their branches being moreover omnidirectional.
• the control of the supply of such a spark plug requires the use of a supply circuit, capable of generating voltage pulses, typically of the order of 100 ns, which can reach amplitudes of the order of 1 kV, at a frequency intended to be very close to the resonance frequency of the radiofrequency resonator of the coil-candle.
• a supply circuit capable of generating voltage pulses, typically of the order of 100 ns, which can reach amplitudes of the order of 1 kV, at a frequency intended to be very close to the resonance frequency of the radiofrequency resonator of the coil-candle.
• Such a power supply circuit is shown diagrammatically in FIG. 2. It conventionally implements a so-called "Class E power amplifier” assembly. This type of DC / AC converter makes it possible to create the voltage pulses with the aforementioned characteristics.
• the amplifier 2 comprises a MOSFET transistor of power M, used as a switch for controlling the commutations across the resonator 1.
• a control device 5 generates and applies a control signal Vl to a control frequency on the gate of the power MOSFET M, via a control stage 3 represented schematically.
• a control signal Vl In order to control the production of sparks between the electrodes of the coil-plug connected at the output of the amplifier when its resonator 1 is excited via the control signal Vl, the latter is not permanent but is present under the form of control pulse trains at the control frequency.
• a parallel resonant circuit 4 is connected between an intermediate voltage source Vinter and the drain of the transistor M.
• This circuit 4 comprises an inductance Lp in parallel with a capacitance Cp.
• the parallel resonator transforms the intermediate voltage Vinter into an amplified voltage Va (illustrated in FIG. 5), corresponding to the intermediate voltage multiplied by the overvoltage coefficient of the parallel resonator.
• This amplified voltage is supplied on the drain of the transistor M, which is also connected to the input of the resonator 1.
• the transistor M therefore acts as a switch and applies (respectively blocks) the voltage Va to the input of the resonator 1 when the control signal Vl is in the high logic state (respectively low).
• the transistor M thus imposes a switching frequency, determined by the control signal Vl, which is sought to make as close as possible to the resonant frequency of the coil-plug connected at the output (typically 5MHz), in order to maintain and maximize the energy transfer between the parallel resonator 4 and the series 1 resonator forming the coil-candle.
• the output voltage Va previously mentioned, multiplied by the overvoltage coefficient of the resonator series 1.
• each combustion chamber is equipped with a coil-candle as described above to initiate, on command, combustion.
• the present invention aims to overcome this disadvantage, by allowing to control a plurality of coils-candles through the same and single amplification channel.
• the subject of the invention is a device for generating plasma, characterized in that it comprises: a power supply circuit, comprising a switch controlled by a control signal for applying an intermediate voltage to a output of the power supply circuit at a frequency defined by the control signal, - a plurality of plasma generation spark plug coils arranged in parallel on the output of the supply circuit via connectors, each connector being adapted to be detachably connected to a corresponding coil-plug and comprising means adapted to shift the resonant frequency of said coil-plug, so that each coil-plug has a distinct resonant frequency, a control device of the circuit supply, determining the frequency of the control signal among one of the resonance frequencies of the coil-candles, so as to control selectively the candle coils according to the control frequency used.
• each plasma-generating coil-coil comprises a resonator having a frequency greater than 1 MHz and comprising two electrodes, the resonator being able to generate a plasma between the two electrodes when a high voltage level is applied to the output of the supply circuit.
• the connectors are assembled together by one and the same connecting piece.
• the connecting piece comprises polarizing means for attaching it to the plurality of bobbins uniquely.
• the means adapted to shift the resonance frequency of a coil-plug comprise means for modifying the inductance value of the coil-plug, located in the immediate vicinity thereof.
• the means for modifying the inductance value of the spark plug coil comprise a winding, positioned directly in contact with a winding of the spark plug coil.
• the winding of the modification means is arranged around an element made of magnetic material.
• the winding of the modification means is surrounded at least in part by a magnetic material element.
• the means for modifying the inductance value of the spark plug coil comprise a magnetic material element positioned directly against a winding of the spark plug coil.
• the element of magnetic material surrounds at least a portion of the end of the coil of the spark plug.
• the element made of magnetic material comprises a central core inserted in the winding of the coil-candle.
• the magnetic material comprises ferrite.
• FIG. 1 is a diagram illustrating an electric model used for the resonator modeling a plasma generation coil-spark plug
• Figure 2 is a diagram illustrating a device for generating a high voltage integrating an amplifier, used for the supply and control of a spark plug coil
• FIG. 3 illustrates a complete diagram of a radiofrequency ignition according to the invention, comprising 4 bobbins arranged in parallel at the output of a single power supply stage;
• FIGS. 4a to 4c illustrate various embodiments of means for shifting the resonant frequency of each coil-plug, designed to be integrated with the connection means of the coil-plugs;
• FIG. 5 illustrates an embodiment of the connection means
• FIG. 6 illustrates a flowchart of an exemplary implementation of the control of the ignition according to the invention.
• the present invention proposes to control a plurality of bobbins-candles, using a single amplification path, in other words by using a single power supply circuit of the class E power amplifier type as previously described in FIG. 2, for selectively supplying the plurality of connected spark-ignition coils in parallel at the output of this supply circuit unique.
• FIG. 3 illustrates such an architecture, in which the single power supply circuit 2 is used, according to the invention, to control separately 4 (and by extension N) coils-candles, respectively BB1, BB2, BB3 and BB4, connected in parallel to the output of the power supply circuit via connection means.
• connection means consist of a plurality of connectors 20, each being adapted to be detachably connected to a corresponding coil-plug of the plurality of spark plugs.
• each of the plasma generating spark plugs has a resonance frequency of its own well separated from the others. This is indeed to avoid overlapping frequency resonance frequency areas resonators forming each coil-candle and thus to overcome the problems of multiple simultaneous ignitions.
• each coil-candle preferably having a resonance frequency identical for reasons of efficiency of the industrial process of producing these candles in particular, the present invention provides to include at each connector 20 means adapted to shift, in a predetermined manner, the resonance frequency of the corresponding coil-plug, so that each coil-plug has a distinct resonance frequency.
• the frequency distribution of the coils-candles thus produced must be such that the difference in resonance frequency between the coils-candles is preferably greater than the bandwidth of each resonator. For example, a difference greater than twice the bandwidth of the resonator will be chosen.
• Figure 4a illustrates the connector 20 of the coil-candle BBl. It is located in the immediate vicinity of the latter and is formed by two conductors 21 and 22, necessary for the command.
• Each connector 20 then incorporates means 23 adapted to shift in a predetermined manner the resonant frequency of the corresponding coil-plug, so that the resonant frequencies offset from the set of coils-candles then satisfy the principles defined above, to to know that the resonance frequencies of each coil-candle are shifted relative to each other by a value preferably greater than twice the bandwidth of each coil-candle.
• the means 23 adapted to shift the resonant frequency of the coil-candle corresponding include means for changing the inductance value of the coil-candle, intended to be located in close proximity thereto.
• these means for modifying the inductance value of the coil-plug comprise an element
• the inductance of the spool-plug sees its modified value as a function of the magnetic material coupled directly to its winding and, more particularly, according to the nature of the material and the geometry of the element attached to the winding.
• the element 30 of magnetic material comprises a central core 32, intended to be inserted into the coil L of the coil-candle.
• the element 30 of magnetic material is configured to surround at least a portion of the end of the coil L of the coil-candle. This configuration also has the advantage of improving the overvoltage coefficient of the spark plug.
• the connector 20 incorporates a coil, in place of the ferrite type magnetic element.
• the coil thus integrated in the connector is intended to be positioned directly in contact with the winding of the coil-candle. The coupling between the two coils then greatly improves the frequency offset.
• the connector 20 incorporates both a coil 34 and a member 36 of magnetic material, for example of the ferrite type, intended to be positioned directly in contact with the coil-candle.
• the coil 34 is then arranged around the magnetic element 36, which can also be configured to surround at least part of said coil.
• the solutions presented above therefore consist in adding to the connector 20 of each coil-candle, an element (ferrite and / or coil) directly against the coil-candle in order to modify its resonance frequency, so as to arrive at the result that each coil-plug connected in parallel at the output of the single supply circuit, then has a resonant frequency of its own, shifted relative to each other as explained above.
• the connectors 20 are assembled together by a single connecting piece 26, which is preferably rigid, then acting as a single connector, to which the aforementioned frequency shift elements are integrated. way to shift the frequency of the coil-candle of each cylinder in a predetermined manner.
• Such a single connector in addition to allowing a minimization of the number of parts and thus an optimization of the manufacturing process, can also be fixed on the motor reliably, so as to ensure good mechanical resistance to vibration, unlike connectors distinct classically used.
• the single connector connecting piece 26 comprises polarization means 27 for fixing it to the plurality of single-chip coils.
• control device then knows in advance the correspondence between the order of the control frequencies of the different coil-candles and the order of the cylinders. This correspondence is stored in the control device.
• the control method of the single power supply circuit must then take into account the frequency adapted to the channel to be controlled for each ignition.
• the control device upon receipt of an ignition request, the control device is firstly able to determine the cylinder to be controlled, numbered from 1 to 4 in the order of disposition on engine. Each cylinder number is therefore associated with the resonance frequency, respectively F1, F2, F3 and F4, specific to the coil-candle to be controlled.
• the control device then comprises a module determining the frequency of the control signal to be generated, among these frequencies F1, F2, F3 and F4, as a function of the number of the cylinder to be ignited and the previously stored correspondence.
• control device applies the control signal to said frequency on an output interface intended to control the switch M.
• the selective power transfer to the coil-candle to be controlled for the ignition is then naturally managed by the control frequency used for this ignition.
• the determination of the resonant frequencies to be obtained at the output of the single supply circuit can be controlled by tabulation or servocontrol methods as described in the French patent applications filed in the name of the applicant FR 05-127669 and FR 05-12770.
• control device may be provided with an interface for receiving engine operating parameter measurement signals (engine oil temperature, engine torque, engine speed, ignition angle, air temperature). inlet, pressure in the combustion chamber, etc.) and / or power supply operating parameter measurement signals, as well as a particular memory module storing relationships between measurement signals and the frequency of a control signal to be generated.
• engine operating parameter measurement signals engine oil temperature, engine torque, engine speed, ignition angle, air temperature
• power supply operating parameter measurement signals as well as a particular memory module storing relationships between measurement signals and the frequency of a control signal to be generated.
• the controller determines the frequency of a control signal to be generated based on received measurements on the receiving interface and relationships stored in the memory module.

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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)
• Plasma Technology (AREA)
• Investigating, Analyzing Materials By Fluorescence Or Luminescence (AREA)

Applications Claiming Priority (2)

Publications (1)

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Citations (9)

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• 2007
  • 2007-03-01 FR FR0701500A patent/FR2913299B1/fr active Active
• 2008
  • 2008-02-25 EP EP08762152A patent/EP2126342A2/de not_active Withdrawn
  • 2008-02-25 RU RU2009136348/06A patent/RU2009136348A/ru not_active Application Discontinuation
  • 2008-02-25 BR BRPI0808177-8A patent/BRPI0808177A2/pt not_active IP Right Cessation
  • 2008-02-25 JP JP2009551245A patent/JP2010520400A/ja active Pending
  • 2008-02-25 US US12/528,452 patent/US8646429B2/en not_active Expired - Fee Related
  • 2008-02-25 CN CN2008800067589A patent/CN101627206B/zh not_active Expired - Fee Related
  • 2008-02-25 WO PCT/FR2008/050311 patent/WO2008113956A2/fr not_active Ceased
  • 2008-02-25 KR KR1020097018198A patent/KR20090115946A/ko not_active Withdrawn

Patent Citations (9)

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