Abstract: An ignition unit produces an ignition in a combustion chamber of a combustion engine in the following manner. The ignition unit comprises a radiofrequency resonator that radiates a plasma-creating radiofrequency field into the combustion chamber. The ignition unit further comprises a microwave resonator that radiates a plasma-boosting microwave field into the combustion chamber. In an embodiment, the microwave resonator has an output surface to which the combustion chamber is exposed when the ignition unit is fitted on the combustion engine. The radiofrequency resonator may comprise an electrode that is at least partially embedded in the microwave resonator. The electrode may have a tip that is located at a distance from the output surface so that the microwave resonator provides a barrier between the tip and the output surface.

Abstract: An ignition unit produces an ignition in a combustion chamber of a combustion engine in the following manner. The ignition unit comprises a radiofrequency resonator that radiates a plasma-creating radiofrequency field into the combustion chamber. The ignition unit further comprises a microwave resonator that radiates a plasma-boosting microwave field into the combustion chamber. In an embodiment, the microwave resonator has an output surface to which the combustion chamber is exposed when the ignition unit is fitted on the combustion engine. The radiofrequency resonator may comprise an electrode that is at least partially embedded in the microwave resonator. The electrode may have a tip that is located at a distance from the output surface so that the microwave resonator provides a barrier between the tip and the output surface.

Abstract: A device for injecting fuel over a cylinder head of an engine, including a tubular body, an injection nozzle forming an extension of the tubular body, a needle extending coaxially to the nozzle in a form of a rod, an end of which includes a head forming a valve on a seat supported by the injection nozzle, and an actuator configured to cause a movement of the head so as to open the valve, the needle configured to axially resonate when the same is subjected to axial pulses at a predetermined nominal frequency by the actuator. A system for mounting the device includes a spacer for bearing on the cylinder head, as well as on a front surface of the tubular body at the connection to the nozzle.

Abstract: A device for radiofrequency ignition of an internal combustion engine, including a power supply circuit including a transformer with a secondary winding connected to at least one resonator that has a resonant frequency in excess of 1 MHz and including two electrodes configured to generate a spark to initiate combustion of a combustible mixture in a cylinder of the engine in response to an ignition command. A measuring capacitor is connected in series between the secondary winding and the resonator, a measurement circuit measures a current at terminals of the measuring capacitor, the current providing an electrical image of how combustion is progressing, and a protection circuit is connected between the capacitor and the measurement circuit and is configured to spare the current measurement acquisition time from electrical effects caused by the ignition command.

Abstract: A sparkplug including an induction coil and an electrode. The induction coil includes two end portions, the electrode extending in a continuation of one of the two end portions. The induction coil includes a conducting wire wound to form a succession of turns, the one of the two end portions having a terminal turn connected to the electrode. The one of the two end portions includes a plurality of coaxial end turns that extend between the terminal turn and an upstream turn, and the terminal turn has a diameter smaller than the diameter of the upstream turn so to reduce strength of the electric field induced in the one of said two end portions near the terminal turn.

Abstract: An injector including a nozzle that includes an opening and a seat, a needle movably mounted in the nozzle and having an end defining a valve in a contact area with the seat, a mechanism for vibrating the valve, a first acoustic-impedance breaking area at a first distance from the valve along the nozzle, and another first acoustic-impedance breaking area at a second distance from the valve along the needle. Each of the first and second distances is such that the respective propagation time of acoustic waves along the distance is: Ti=ni*[?/2], where ni is a positive integer coefficient different from zero with i=3 for the first distance and i=4 for the second distance, ? being a period of the vibrations.

Abstract: A plasma generating device including: a supply circuit including a switch controlled by a control signal for applying an intermediate voltage on an output of the control circuit at a frequency defined by the control signal; a plurality of plasma-generating plug coils arranged in parallel on the output via connectors, each connector being adapted to be removably connected to a corresponding plug coil and including a mechanism adapted to offset the resonance frequency of the plug coil so that each plug coil has a distinct resonance frequency; a control device of the supply circuit, that determines the control frequency from the resonance frequencies of the plug coils to selectively control the plug coils according to the control frequency used.

Abstract: A sparkplug including an induction coil and an electrode. The induction coil includes two end portions, the electrode extending in a continuation of one of the two end portions. The induction coil includes a conducting wire wound to form a succession of turns, the one of the two end portions having a terminal turn connected to the electrode. The one of the two end portions includes a plurality of coaxial end turns that extend between the terminal turn and an upstream turn, and the terminal turn has a diameter smaller than the diameter of the upstream turn so to reduce strength of the electric field induced in the one of said two end portions near the terminal turn.

Abstract: A supply device for a radio frequency ignition system, including a supply circuit to provide a supply voltage to an output connected to a plasma generation resonator at a frequency defined by a control signal provided by a control device for the supply circuit. The control device includes a receiver interface for a determination request for the optimum control frequency, a receiver interface for receiving signals measuring the voltage at the pins of a capacitor in the supply circuit, a determination module for the optimum control frequency, to provide successive different control frequencies for the supply circuit for successive ignition commands on reception of a request and to determine an optimum control frequency based on received measured signals.

Abstract: A high voltage resonator-amplifier for a radiofrequency ignition system that can be used in an internal combustion engine, the resonator-amplifier including at least two electrodes, a coil arranged in alignment with the electrodes along a longitudinal axis, and a linking mechanism retaining the coil and the electrodes in a relatively fixed position. The coil is wound around a closed bend which in turn wraps around the longitudinal axis.

Abstract: A measuring device including: a supply circuit for radiofrequency ignition including a transformer including a secondary winding connected to at least one resonator having a resonance frequency higher than 1 MHz, and including two electrodes capable of generating a spark upon an ignition control; a measuring capacitor connected in series between the secondary winding and the resonator; a measuring circuit of ionization current of the combustion gases in a cylinder of the internal combustion engine associated with the resonator, the circuit being connected at terminals of the measuring capacitor; and/or a measuring circuit that measures a voltage at the resonator terminals upon an ignition control, the circuit being connected to terminals of the measuring capacitor.

Abstract: A method for controlling a radio-frequency plasma generator including a supply circuit with a switch controlled by at least one control pulse train, for applying an intermediate voltage at a control frequency on an output to which is connected a resonator for generating a spark between two electrodes when a high voltage level is applied to the output. The method receives first and second measurement signals respectively representative of the operation of a combustion engine and of the type of spark generated; and real-time adjusts, based on the received measurement signals, at least one parameter selected from at least the intermediate voltage level, the control frequency, and the duration of the control train, to promote branching of the spark generated.

Abstract: An internal combustion engine radio frequency spark plug including two plasma-generating electrodes, separated by an insulator, that constitute respectively an outer shell enclosing the insulator and a central electrode housed in a central bore of the insulator. The spark plug includes a deep opening over the entire circumference of the shell, forming a heat-exchanger chamber inside the spark plug shell, opening outwards.

Abstract: A device including two plasma generation electrodes, a series resonator having a resonant frequency above 1 MHz and including a capacitor with two terminals, and an induction coil surrounded by a screen, the capacitor and the coil being placed in series, the electrodes being connected to the respective terminals of the capacitor. The ratio of the spark plug to the radius of the screen is equal to 0.56. The device can optimize the Q-factor of such a device by adjusting the radius of the coil to that of the screen.

Abstract: A device for injecting fuel over a cylinder head of an engine, including a tubular body, an injection nozzle forming an extension of the tubular body, a needle extending coaxially to the nozzle in a form of a rod, an end of which includes a head forming a valve on a seat supported by the injection nozzle, and an actuator configured to cause a movement of the head so as to open the valve, the needle configured to axially resonate when the same is subjected to axial pulses at a predetermined nominal frequency by the actuator. A system for mounting the device includes a spacer for bearing on the cylinder head, as well as on a front surface of the tubular body at the connection to the nozzle.

Abstract: The invention relates to an injector including a needle mounted in a nozzle and having an end defining a valve, the needle being connected at the other end to an actuator including first, second and third portions, the first and third portions being provided on either side of the second portion, the three portions being tightened together in order to form a block having two axially opposite limits, the first portion being connected with the needle at one of said limits, and an excitation means for vibrating the second portion according to setpoint period ?. According to the invention, the length between the two limits of the block is such that the propagation time T of the acoustic waves generated by the vibrations of the second portion of the actuator and running along that length meets the equation: T=n*[?/2], where n is an integer positive multiplication coefficient different from zero.

Abstract: A high voltage resonator-amplifier for a radiofrequency ignition system that can be used in an internal combustion engine, the resonator-amplifier including at least two electrodes, a coil arranged in alignment with the electrodes along a longitudinal axis, and a linking mechanism retaining the coil and the electrodes in a relatively fixed position. The coil is wound around a closed bend which in turn wraps around the longitudinal axis.

Abstract: A fuel injector for an internal combustion engine, particularly of inwards or outwards opening needle injector type, includes an injector body, e.g., forming a nozzle ending in an injection office, a mechanism for closing off the injection orifice of the injector body, the closing-off mechanism including a vibrating pintle ending in a head for closing off the injection orifice, a return mechanism returning the closing-off to the position in which they close off the injection orifice, and a mechanism for setting the pintle and/or the nozzle into cyclic longitudinal vibration so as to open and close the injection orifice alternately. The fuel injector includes a selectively activatable mechanism immobilizing the pintle with respect to the body.

Abstract: A device for measuring an ionization current of a spark plug of a type with a resonant structure, including a motor vehicle ignition system, the spark plug being coupled to a generator including a regulating capacitor. The generator includes a polarizer that polarizes the spark plug, connected between the generator and the spark plug, and a device that measures ionization current of the spark plug, connected between the regulating capacitor and ground.

Abstract: A spark plug for a motor vehicle internal combustion engine, substantially elongated in shape, and including: two coaxial electrodes of an inner central electrode and an outer base electrode enclosing the central electrode; and an electrically insulating annular block, interposed between the central electrode and the base electrode and including an annular shoulder. The insulating annual block includes an annular groove located at the shoulder.