Classifications

• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02N—ELECTRIC MACHINES NOT OTHERWISE PROVIDED FOR
  • H02N2/00—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction
  • H02N2/02—Electric machines in general using piezoelectric effect, electrostriction or magnetostriction producing linear motion, e.g. actuators; Linear positioners ; Linear motors
  • H02N2/06—Drive circuits; Control arrangements or methods
  • H02N2/065—Large signal circuits, e.g. final stages
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D41/2096—Output circuits, e.g. for controlling currents in command coils for controlling piezoelectric injectors
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D2041/2003—Output circuits, e.g. for controlling currents in command coils using means for creating a boost voltage, i.e. generation or use of a voltage higher than the battery voltage, e.g. to speed up injector opening
• • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
  • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
  • F02D—CONTROLLING COMBUSTION ENGINES
  • F02D41/00—Electrical control of supply of combustible mixture or its constituents
  • F02D41/20—Output circuits, e.g. for controlling currents in command coils
  • F02D2041/202—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit
  • F02D2041/2048—Output circuits, e.g. for controlling currents in command coils characterised by the control of the circuit said control involving a limitation, e.g. applying current or voltage limits

Definitions

• the present invention relates to the field of electronic injection in an internal combustion engine of a motor vehicle.
• the invention relates more particularly to a device and a method for controlling a fuel injector with a resonant ultrasonic piezoelectric stage.
• a known structure of a control device of this type is shown schematically in FIG.
• Such a device is designed to control at least one resonant ultrasonic piezoelectric stage 1 of a pilot mjector electronically from a control computer 10 and a DC voltage source V BATT / vehicle battery for example.
• the control device comprises: a first stage 2 for raising the DC voltage V BATT to generate a DC intermediate voltage V in ter (a few hundred volts, for example 250V),
• a second stage 3 for modulating the intermediate DC voltage V inte r / fed by the DC intermediate voltage V inte r and adapted to generate an alternating excitation voltage V E of the resonant ultrasonic piezoelectric stage 1.
• FIG. 2 illustrates a "boost" type voltage converter circuit, conventionally used to realize the stage 2 of voltage rise from the DC voltage source V BATT , for example the battery with a capacity C ba tt •
• This circuit is composed of a boost inductor L, a MOSFET K, which serves as a switch controlled by a control module 20, a boost diode D, and a storage capacitor C boos t-
• the control module delivers a signal in the form of a high frequency pulse train, so that the transistor K is made periodically conductive.
• the inductance L boost is charged with the voltage V BATT at its terminals.
• an object of the invention is to propose a solution so that the amplitude of the envelope of the excitation signal of the resonant ultrasonic piezoelectric stage of the mjector at the output of the stage can be varied very rapidly. modulation, while maintaining a reasonable sizing control electronics, ensuring an acceptable volume / weight / cost compromise in the context of automotive engine control.
• the invention relates to a device for controlling at least one resonant ultrasonic piezoelectric stage of an electronically controlled injector from a control computer and a DC voltage source, comprising: a first stage of raising the DC voltage to generate a DC intermediate voltage, and
• a second modulation stage of the intermediate DC voltage comprising an inductance connected to the DC intermediate voltage and a first switching transistor adapted to control selectively a charging phase of the inductor and a transfer phase of the energy stored in the inductor in response to a first control pulse train, for generating an excitation voltage of the ultrasonic piezoelectric stage resonant.
• the invention is more particularly characterized in that the second stage comprises a second switching transistor connected in series between the drain of the first switching transistor and a terminal of the inductor, adapted to limit the energy stored in the inductance during the charging phase in response to a second train of control pulses, so as to decrease the amplitude of the excitation voltage.
• the drain of the first switching transistor is connected to the resonant ultrasonic piezo-echo stage via a capacitor.
• the drain of the first switching transistor may further be connected to the resonant ultrasonic piezoelectric stage via a transformer.
• the primary winding of the transformer is connected by a terminal to the drain of the first switching transistor and by another terminal to ground, the primary winding being connected in parallel with the capacitor.
• the drain of the second switching transistor is connected to the resonant ultrasonic piezoelectric ⁇ stage via a transformer.
• the primary winding of the transformer is connected by a terminal to the voltage intermediate intermediate and by another terminal to the drain of the second switching transistor, a capacitor being connected between the DC intermediate voltage and the drain of the first switching transistor.
• the second control pulse train is a PWM signal adapted to control the second switching transistor in an open state during at least a portion of the charging phase during which the first switching transistor is controlled in a closed state.
• the first voltage rise stage comprises a BOOST type voltage converter.
• the invention also relates to a method of controlling at least one resonant ultrasonic piezoelectric stage of an electronically controlled thruster from a control computer and a DC voltage source, comprising steps of:
• the decrease in the amplitude of the excitation voltage of the resonant ultrasonic piezoelectric stage depends on the opening time of the second switching transistor during each charging phase.
• FIG. 1 represents a simplified electronic diagram of FIG. a known control device of an ultrasonic piezoelectric stage resonant of a fuel injector of an internal combustion engine and has already been described
• FIG. 2 represents an electronic diagram of an embodiment of a first stage of the known control device of FIG. 1, forming a voltage boost stage of the "boost" type, and has already been described;
• FIG. 3 represents a timing diagram illustrating a dynamic amplitude variable amplitude envelope profile of the control voltage obtained at the output of a second voltage modulation stage of the control device according to the invention
• FIG. 4 represents an electronic diagram of an embodiment of the second voltage modulation stage of the known control device connected to the piezoelectric stage of the injector
• FIG. 5 represents an alternative embodiment of FIG. 4;
• FIG. 6 represents an electronic diagram of the voltage modulation stage of an injector control device according to the invention, based on a half-bridge type structure with series inductance;
• FIGS. 7 to 9 represent variants of the circuit of FIG. 6 with several possible configurations of passive circuits downstream from the half-bridge type structure;
• FIG. 10 represents timing diagrams of the respective control signals of the transistors composing the half-bridge type structure on which the voltage modulation stage of the injector control device according to the invention is based;
• FIG. 11 represents an example of modulation of the excitation signal of the injector according to the principles of the invention.
• the invention is based on the control device with the stages of voltage rise and modulation, already described with reference to FIG.
• the invention proposes to modify the modulation stage of the control device described above, so as to be able to vary the amplitude of the excitation voltage supplied at the output of this stage (and therefore at the input of the injector concerned). with great dynamics.
• This principle of amplitude variation of the excitation voltage envelope of the injector with a significant dynamic is described with reference to Figure 3, which has a profile V excitation voltage envelope V E , able to allow particularly flexible injection controls. It is therefore a question of being able to modulate the amplitude of the peaks of the excitation voltage of the mjector, in addition to the modulation performed by the modulation stage, which consists in producing the voltage peaks themselves, preferably at the resonant frequency of the mjector.
• the modulation stage 3 of the control device according to the invention is based on an otherwise known topology, described in Figure 4.
• the voltage modulation stage 3 is thus implemented in the form of a pulse voltage generator, able to deliver the excitation voltage V E of the ultrasonic piezoelectric stage 1 of the mjector connected to the output in the form of a voltage pulse train in response to a control pulse train Vi at a suitable frequency received on a control electrode of a switching transistor M, for example a MOSFET transistor, by via a driver stage 30.
• this pulse voltage generator comprises an inductance coil L p , connected to the intermediate DC voltage V inte r (output of the voltage rise stage 2) and driven by the transistor M, and a capacitor in FIG. parallel of the coil, capacitance C p , at the terminals of which is connected the resonant ultrasonic piezoelectric stage 1.
• the resonant ultrasonic piezoelectric stage injector can be modeled by a greenhouse resonator comprising a resistor in series with inductance and capacitance.
• the combination of the pulse voltage generator and the series resonator modeling the charge of the resonant ultrasonic piezoelectric injector is commonly called by those skilled in the art "pseudo class E amplifier".
• the drain of the latter makes it possible to deliver the voltage pulse train V E able to excite the resonant ultrasonic piezoelectric ⁇ stage. 1, which is connected to the output of the modulation stage 3.
• the pulse voltage generator comprises a set of transformers T and capacitor C p connected in parallel between the intermediate intermediate voltage V inter and the drain of the switching transistor M.
• the drain of the switching transistor M is connected to the resonant ultrasonic piezoelectric stage 1 via the transformer T, whose primary winding is connected in parallel with the capacitor C p between the intermediate intermediate voltage V ulcerer and the drain of the transistor M and the secondary winding of which is connected to the resonant ultrasonic piezoelectric stage 1.
• the operating cycle of class E amplifiers is based on two phases of operation, repeated constantly at the frequency defined by the control train, corresponding to the resonance frequency of the charge resonator: - Charge phase: the transistor M is closed; the charge resonator is short-circuited and resonates "on itself” (it loses some energy in its dissipative elements), while the inductance L p is charged because it is powered by V inte r.
• Transfer phase the transistor M is open; the energy stored in the inductor is redirected towards the charge resonator and compensates for the losses thereof.
• FIG. 6 describes a new topology for the modulation stage, modifying the "class E" type operation thereof, so as to be able to vary very rapidly the amplitude of the excitation signal V E output of this stage (thus at the entrance of the mjecteur concerned).
• the voltage modulation stage 3 is based on a structure of the type "half-bridge with series inductance".
• the half-bridge structure is composed of two transistors M and M 'connected in series between the ground and an inductance coil Lp supplied by the intermediate intermediate voltage V inter .
• the voltage generator pulse forming the voltage modulation stage 3 comprises a second switching transistor M ', for example a MOSFET transistor, connected in series between the drain (point C in FIG. 6) of the transistor M (whose source is connected to the mass) and a terminal
• FIG. 7 details a direct amplitude modulation topology, that is to say for which the resonant ultrasonic piezoelectric stage of the mjector is connected directly to the transistors M and M 'constituting the structure of the type half-bridge.
• This topology has the advantage of simplicity and cost.
• it is not possible to control injectors with an output amplitude greater than the maximum insulation characteristic of the transistors used (approximately 1200 V for IGBT type transistors ("Insulated Gate Bipolar Transistor") that can be used in the automotive context.
• T-transformer topologies such as those presented with reference to FIG. 8 and FIG. 9 can be used.
• the drain of the second switching transistor M ' is connected to the resonant ultrasonic piezoelectric stage 1 via a transformer T. More precisely, the primary winding of the transformer is connected between the intermediate voltage Continuous V in ter and the drain of the second switching transistor M ', the inductance coil L p being constituted by the primary winding of the transformer T, and the secondary winding is connected across the piezoelectric stage. resonant ultrasound.
• a capacitor C p is further connected between the intermediate DC voltage V inter and the drain of the first switching transistor M.
• a transformer T and capacitor C p is connected in parallel between the drain of the first switching transistor M and ground. More specifically, the drain of the first switching transistor M is connected to the resonant ultrasonic piezoelectric stage 1 via the transformer T, whose primary winding is connected in parallel with the capacitor C p between the transistor drain. M and the mass, the secondary winding of the transformer being connected to the resonant ultrasonic piezoelectric stage 1.
• Both variants make it possible to generate amplitudes much greater than the insulation characteristic of the transistors used, which also makes it possible to choose a compromise between the transformation ratio of the transformer and the characteristics transistors adapted to high efficiency and lower cost.
• the advantage of the latter lies in the fact that, unlike the "strict" class E topology (FIG. 4 or 5), it is possible to short-circuit the charge resonator modeling the resonant ultrasonic piezoelectric stage 1, without however systematically charging the series inductance L p connected to the intermediate intermediate voltage V inter (output of the stage 2 elevator of voltage).
• the second switching transistor M ' is opened for some time, it is possible to close the first switching transistor M so as to resonate the resonant ultrasonic piezoelectric stage 1 of the injector, without however charging the inductance L p , which is then disconnected from the ground by the second switching transistor M ', which allows, in its open state, to disconnect the drain of the first switching transistor M of the inductance Lp.
• the present topology based on the half-bridge type structure composed of the two switching transistors M and M 'respectively controlled by the control pulse trains Vi and V 2 , thus makes it possible to modify the class E operating cycle of the voltage modulation stage 3, so as to be able to generate an excitation voltage V E at variable amplitude output.
• it makes it possible to introduce a new phase, in addition to the charging and transfer phases, into the operating cycle of the class E amplifiers, namely a resonance phase without charge of the inductance in series with the half composed of transistors M and M ', so as to be able to generate an output of variable amplitude.
• control mode of the two transistors constituting the half-bridge is mainly based on the characteristics of the control pulse train V 2 controlling the opening and closing of the second switching transistor M '.
• control pulse train Vi controlling the opening and closing of the switching transistor M does not change with respect to the control train employed in the "strict" class E topology, described with reference to FIGS. 4 or 5.
• Such a control pulse train V 1 is illustrated in FIG. 10 as a rectangular signal.
• the reduction of the width of the first pulse makes it possible to minimize the overvoltage of the first peaks, overvoltage which can be very important (and therefore potentially destructive for the transistor) in the first moments of the injection.
• each operating cycle during an injection control therefore comprises the application of a high state of the control pulse train Vi to the gate of the transistor M (closed transistor), controlling the charging phase where the inductance L p fed by V inte r load and the application of a low state of the control pulse train Vi on the gate of the transistor M (open transistor), controlling the transfer phase where the energy stored in the inductance is redirected to the resonant ultrasonic piezoelectric stage.
• this control pulse train Vi is essential to use as a phase reference for the second control pulse train V2 of the second switching transistor M '.
• the second control pulse train V 2 is for example a PWM ("Pulse Width Modulation") signal, ie a rectangular signal whose duty cycle can be varied, so that the opening and closing times can be controlled. of the second switching transistor M '. It is more precisely used to control opening times of the transistor M ', during which it is desired to limit the load of the series inductance L P; while the first switching transistor M is closed.
• PWM Pulse Width Modulation
• This opening configuration of the second switching transistor M 'during at least part of the charging phase makes it possible to limit the stored energy. in the inductor series L p at each operating cycle and therefore the total amplitude of the signal supplied at the output of the E class modulation stage 3 in steady state.
• the amplitude of the excretatron tensron V E generated at the output of the stage 3 essentially depends on the opening time D of the second switching transistor M 'at each cycle. The longer this opening time, the more energy stored periodically in the series inductance is low and the amplitude of the excitation voltage V E is reduced.
• This opening time can be managed by varying the duty cycle of the control pulse train V2.
• the first switching transistor M is controlled in the open state (low state of the pulse train). Vi) prior to the start of the injection, and - the second switching transistor M 'is controlled in the closed state (high state of the control pulse train V 2 ) before the start of the injection.
• full amplitude operation where the second switching transistor M 'is constantly controlled in the closed state.
• the operation is in this case identical to the operation of the basic class E modulation stage as described with reference to FIGS. 4 or 5, and a so-called “partial amplitude” operation, in which the second switching transistor M 'is controlled in the open state during the charging phase (that is to say while the first switching transistor M is closed) and controlled in the closed state during the transfer phase (that is to say while the first switching transistor M is open), according to the principles already described above.
• This second mode of operation based on the periodic opening of the second switching transistor M 'thus makes it possible to control the amplitude of the envelope of the signal V E at the output of the stage 3, this throughout the duration of the injection.
• FIG. 11 Such an envelope modulation is illustrated in FIG. 11.
• the maximum amplitude of the voltage V E is obtained by constantly controlling the transistor M 'in the closed state.
• the application of the control pulse train V2 in the form of a PWM signal on the gate of the switching transistor M ' makes it possible to limit the value of the amplitude of the injection. the voltage V E.

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• Engineering & Computer Science (AREA)
• Chemical & Material Sciences (AREA)
• Combustion & Propulsion (AREA)
• Mechanical Engineering (AREA)
• General Engineering & Computer Science (AREA)
• Fuel-Injection Apparatus (AREA)
• Amplifiers (AREA)
• Dc-Dc Converters (AREA)
• General Electrical Machinery Utilizing Piezoelectricity, Electrostriction Or Magnetostriction (AREA)

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• 2008
  • 2008-10-14 FR FR0856939A patent/FR2937196B1/fr not_active Expired - Fee Related
• 2009
  • 2009-10-13 CN CN2009801453190A patent/CN102216595A/zh active Pending
  • 2009-10-13 EP EP09756011A patent/EP2334922A1/fr not_active Withdrawn
  • 2009-10-13 WO PCT/FR2009/051944 patent/WO2010043808A1/fr active Application Filing
  • 2009-10-13 US US13/124,335 patent/US20110273057A1/en not_active Abandoned
  • 2009-10-13 JP JP2011530536A patent/JP2012505625A/ja not_active Withdrawn

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