Abstract: A spark plug including: a central electrode including an upper end and a lower end; an insulating part including an upper portion and a lower portion and surrounds the central electrode so that the lower end of the central electrode extends beyond the lower portion of the insulating part; and a cap including an upper portion and a lower portion that has an end section and that surrounds the insulating part so that the lower portion of the insulating part extends beyond the lower portion of the cap. The insulating part includes an annular groove, on the external periphery thereof, on the lower end of the cap, and the lower end section of the cap is placed in the groove.

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 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 spark plug including: a central electrode including an upper end and a lower end; an insulating part including an upper portion and a lower portion and surrounds the central electrode so that the lower end of the central electrode extends beyond the lower portion of the insulating part; and a cap including an upper portion and a lower portion that has an end section and that surrounds the insulating part so that the lower portion of the insulating part extends beyond the lower portion of the cap. The insulating part includes an annular groove, on the external periphery thereof, on the lower end of the cap, and the lower end section of the cap is placed in the groove.

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 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: 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 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.

Abstract: A spark plug for an internal combustion engine of a motor vehicle, having a substantially cylindrical general form, includes an essentially capacitive lower part and an essentially inductive upper part. The lower part includes two coaxial electrodes, including a central electrode with an axis and a shell electrode that surrounds the central electrode, and an insulator inserted between the central electrode and the shell electrode. The upper part includes a central mandrel surrounded by a coil, a bottom end part of which overlaps a top end part of the central electrode in a radial direction, an external casing, and an insulator inserted radially between the casing and the coil. The top end part of the central electrode has a coating of material which is more electrically conductive than the material of the central electrode and has no ferromagnetic properties.

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: 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 fluid injection device having a main injection axis and including at least: a housing; an actuator axially mounted in the housing and including a stack with two axially opposed front faces and including at least one electro-active portion with an electro-active material; and a pre-stressing mechanism adapted for at least partially pre-stressing the stack. The pre-stressing mechanism includes at least a tightening clamp outside the stack and provided between the stack and the housing.

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: Sparkplug (1) for the internal combustion engine of a motor vehicle, of substantially cylindrical overall shape, comprising: —an essentially capacitive lower part (C) comprising: •two coaxial electrodes: an internal electrode of axis (D) termed the central electrode (3) and an external electrode termed the shell (2) surrounding the central electrode (3) •an electrically insulating block termed the insulator (4) inserted between the central electrode (3) and the shell (2), —an essentially inductive upper part (I) comprising: •a central sleeve (8) surrounded by a coil (5), a bottom end part (57) of which surrounds a top end part (31) of the central electrode (3) •an external casing (6), •an insulator (7) inserted radially between the casing (6) and the coil (5) characterized in that the top end part (31) of the central electrode (3) has a coating (9) of material which: —has greater electrical conductivity than the material of the central electrode (3), —has no ferromagnetic properties.

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.