Abstract: An ultrasonic transducer includes a stack of flat electrodes between which are interposed ceramic wafers of substantially same surface area as the electrodes, stacked contours of the ceramic wafers and electrode wafers defining substantially flat or cylindrical side faces of the stack. A method of manufacturing the transducer includes: alternatively stacking a ceramic wafer and an electrode wafer, placing between each ceramic wafer and its two neighboring electrodes a composition of which at least 75% by weight, or at least 80% by weight, that includes silver nanoparticles having a grain size of smaller than or equal to 80 nanometers, or smaller than or equal to 60 nanometers; and compressing the stack by heating to a temperature of less than or equal to 280° C., or between 200° C. and 250° C.

Abstract: A process for producing an actuator configured to generate powerful ultrasonic waves and that includes a stack of alternating intermediate electrode layers and piezoelectric material layers. The method includes: forming an initial stack of alternating intermediate electrode layers and piezoelectric material layers, each end of the stack being a piezoelectric material layer or an intermediate electrode layer; firmly attaching adjacent layers to one another; cutting the initial stack into elementary blocks; and connecting the intermediate electrode layers together, in each elementary block.

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: An ultrasonic transducer includes a stack of flat electrodes between which are interposed ceramic wafers of substantially same surface area as the electrodes, stacked contours of the ceramic wafers and electrode wafers defining substantially flat or cylindrical side faces of the stack. A method of manufacturing the transducer includes: alternatively stacking a ceramic wafer and an electrode wafer, placing between each ceramic wafer and its two neighbouring electrodes a composition of which at least 75% by weight, or at least 80% by weight, that includes silver nanoparticles having a grain size of smaller than or equal to 80 nanometres, or smaller than or equal to 60 nanometres; and compressing the stack by heating to a temperature of less than or equal to 280° C., or between 200° C. and 250° C.

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 process for producing an actuator configured to generate powerful ultrasonic waves and that includes a stack of alternating intermediate electrode layers and piezoelectric material layers. The method includes: forming an initial stack of alternating intermediate electrode layers and piezoelectric material layers, each end of the stack being a piezoelectric material layer or an intermediate electrode layer; firmly attaching adjacent layers to one another; cutting the initial stack into elementary blocks; and connecting the intermediate electrode layers together, in each elementary block.

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: An injection device for injecting pressurized fluid includes a housing, an actuator, and an energizing unit. The housing includes at least one axial cavity filled with pressurized fluid. The actuator includes a stack with a first transverse face extended axially by a penetrating member and a second transverse face axially opposite the first. The stack includes at least one electroactive part including an electroactive material. The member includes a piston engaged in the cavity and forming a fluidic connection between the actuator and the housing. The energizing unit sets the electroactive part of the actuator in vibration with a set period ?. The penetrating member includes an axial length such that the propagation time T of the acoustic waves produced by the vibrations of the electroactive part of the actuator and traveling along this length satisfies the following equation: T=[2n+1]*[?/4], where n is a positive integer coefficient.

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 fuel injecting device and method of controlling the fuel injection device. The fuel injection device includes a cylindrical body, a needle whose end includes with a head forming a valve on a seat supported by the end of the cylindrical body, an actuator made of an electroactive material, including a rod and that displaces the head such that the valve is opened, and a prestressing device holding the needle and a counterweight such that they are pressed against the rod opposite end. The needle extends coaxially to the cylindrical body in a form of a rigid bar and axially resonates when exposed to axial pulses at a determined excitation frequency by the actuator.

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 fuel injecting device and method of controlling the fuel injection device. The fuel injection device includes a cylindrical body, a needle whose end includes with a head forming a valve on a seat supported by the end of the cylindrical body, an actuator made of an electroactive material, including a rod and that displaces the head such that the valve is opened, and a prestressing device holding the needle and a counterweight such that they are pressed against the rod opposite end. The needle extends coaxially to the cylindrical body in a form of a rigid bar and axially resonates when exposed to axial pulses at a determined excitation frequency by the actuator.

Abstract: A fluid injection device including a protruding needle. One end of the needle forms a valve and can be moved between a closed position, in which the valve seals the fluid-release opening, and an open position, in which the valve is positioned at a controlled distance from the opening. Movement of the valve between the closed position and the open position is produced by the controlled intrinsic extension of the protruding needle.

Abstract: A fluid injection device including a protruding needle. One end of the needle forms a valve and can be moved between a closed position, in which the valve seals the fluid-release opening, and an open position, in which the valve is positioned at a controlled distance from the opening. Movement of the valve between the closed position and the open position is produced by the controlled intrinsic extension of the protruding needle.

Abstract: An improved fluid drop ejector is disclosed which includes one wall including a thin elastic membrane having an orifice defining a nozzle and elements responsive to electrical signals for deflecting the membrane to eject drops of fluid from the nozzle.