Abstract: The circuit comprises a first threshold comparator (2,3) with hysteresis which is arranged to provide a reference signal (V.sub.c) indicative of the zero-crossing of the sensor signal (V.sub.p). Also connected to the sensor (P) is an integrator circuit (4) whose output is connected to the input of a second threshold comparator (7). The latter provides an inabling output signal (V.sub.e) only when the integrated signal (V.sub.i) exceeds a reference signal (V.sub.2) whose amplitude varies in a predetermined manner in dependance on the amplitude of the integrated signal (V.sub.i). An inabling circuit (14) is connected to the two threshold comparators (2,3;7) and outputs the signal (V.sub.c) generated by the first comparator (2,3) only when the second comparator (7) emits an enabling output signal (V.sub.e).

Abstract: The circuit includes a threshold comparator which compares the signal provided by the sensor with that provided by a threshold-signal generator. The threshold-signal generator circuit comprisesa peak-detector circuit connected to the sensor,a capacitor connected between the output of the peak-detector circuit and the threshold-signal input of the comparator, anda reset circuit controlled by the output of the threshold comparator so as to cause the capacitor to discharge every time the signal provided by the sensor exceeds the threshold signal.

Abstract: An ignition system for an internal combustion engine comprises a direct-current supply, at least one spark plug, an ignition coil with a primary winding and a secondary winding for connection to the supply and to the at least one plug, respectively, a first electronic switch between the primary winding and the supply, an inductor between the supply and the primary winding of the coil, a capacitor in parallel with the circuit branch including the primary winding and the first switch, a second electronic switch between the inductor and the supply and adapted to disconnect the circuit downstream of the inductor from the supply in its closed condition, and an electronic unit which controls the first and second switches in a predetermined manner.

Abstract: An electrical force and/or deformation sensor includes a support structure constituted by a rigid plate in one face of which a recess is formed. The bottom wall of the recess is thin and is resiliently deformable under the action of a force or pressure to be measured. At least one piezoresistive sensitive element constituted by a thick-film resistor is applied to the other face of the plate in correspondence with the recess. Electrical conductor elements connected to the sensitive element or elements are also applied to this face of the plate to enable its connection to supply and processing circuits. These circuits may conveniently be produced by thick- or thin-film hybrid circuit technology on the same face of the support plate as that which carries the piezoresistive element or elements. In order to measure absolute pressure, the inlet opening of the recess may be closed by a gas-tight seal so as to define a closed cavity in the thickness of the plate, in which a vacuum is formed.

Abstract: The transducer comprises a support structure carrying piezoresistive sensors, particularly of the thick-film type, which are intended to be resiliently deformed by the fluid pressure to be measured and to provide an electrical signal indicative of the value of the pressure. The support structure comprises a substantially mushroom-shaped metal body with a head and a shank. An axial blind hole is formed in the shank and is intended to contain the fluid whose pressure is to be measured. The hole also extends into the head and, with the end surface of the head, defines a wall which is resiliently deformable by the pressure to be measured. The piezoresistive sensors are connected to the end surface of the head of the mushroom-shaped body in correspondence with or adjacent the deformable wall so that they can in turn be deformed as a result of the deformation of the wall. The piezoresistive sensors are deposited on a thin plate fixed to the upper surface of the head of the mushroom-shaped body.

Abstract: In a first operative mode, the control unit first causes energy to be stored by the inductor and then connects the inductor to the capacitor so as to form a resonance circuit whose energy is discharged into the primary winding of the coil in order to generate a spark. In a second operative mode, the unit causes a plurality of cycles to be effected to charge the capacitor so as to increase the voltage across its terminals at each cycle and the capacitor is then discharged into the primary winding of the ignition coil in order to generate the spark.

Abstract: A circuit for piloting an inductive load comprises a low-voltage supply, a storage inductor interposed between one pole of the supply and the load, a first electronic switch in parallel with the load, a second electronic switch in series with the load, between the load and the other pole of the supply, a third electronic switch interposed between the first pole of the supply and the junction between the load and the second switch, and an electronic control unit arranged to pilot the switches in a predetermined manner.The storage inductor is permanently connected to the first pole of the voltage supply and a conductive bypass path is provided between the first pole of the supply and the load. The control unit is arranged to cause the second and third electronic switches to open and close successively in counterphase, in order to maintain the current in the load at a predetermined average level.

Abstract: The signal provided by an accelerometric sensor (S) connected to the engine is monitored in two frequency bands (f1, f2) in which peaks indicative of the presence of pinking (knocking) may appear. The intensity of the signal detected in the second band (f2) is compared (3) with the intensity of the signal detected in the first band (f1). The comparison (20) of the detection-signal component (F1 and/or F2) with the noise component (F3), in view of the emission of the pinking signal (21), is carried out in different ways (8, 13, 14) according to the relative ratios between the above intensities.

Abstract: The sensor comprises a body defining a closed chamber which is partially filled with electrically conductive liquid. A main electrode and first and second auxiliary electrodes extend within the chamber in such a way that a variation in the inclination of the body from a predetermined position causes a corresponding variation in the electrical resistance between each auxiliary electrode and the main electrode. The monitoring circuit for the sensor comprises a generator which applies square-wave signals to the auxiliary electrodes in counterphase, and a detector/amplifier which is synchronized with the generator and samples the signal taken from the main electrode in the sensor.

Abstract: A circuit for controlling an inductive load for an electro-injector of a diesel-cycle internal combustion engine is operated from the vehicle battery and includes a reactive circuit having an energy-storage inductor. A first switch controls the supply of current to the energy-storage inductor and a second switch is provided for connecting the reactive circuit to the inductive load for rapid discharge of the energy stored in the energy-storage inductor load into the inductive so as to inject a current pulse into the load. A by-pass branch circuit is connected between the first switch and the load and includes additional switch for enabling the passage of current from the battery to the load when the first and second switches are simultaneously closed.

Abstract: An ignition system for at least one spark plug of an internal combustion engine includes an ignition coil having a secondary winding connected to the plug, a control commutator device controlling the flow of current in the primary winding of the ignition coil, a device for monitoring the intensity of the current flowing in the primary winding and electrical sensors which provide signals indicative of the operating conditions of the engine. A control unit is provided with memory devices in which are stored data indicative of predetermined final values for the current in the primary winding of the ignition coil associated with various operating conditions of the engine. The control unit is also arranged to pilot the commutator device so that each time a spark needs to be generated the flow of current in the primary winding of the ignition coil is stopped when the magnitude of current has reached the final value which is associated in the memory device with the prevailing operating conditions of the engine.

Abstract: The invention relates to an angular measurement device comprising a variable reluctance magnetic circuit comprising a fixed portion (3) associated with a coil (2) and at least a moving element (4) attached to a part (5) rotating in front of the fixed portion, the angular position of which is to be detected, comprising: means (I) for integrating the voltage across the coil, means for measuring the instantaneous value of the integrated voltage (15), means for comparing this measure to a calibrating curve of the integrated voltage versus the angle.

Abstract: A piloting circuit for inductive loads, particularly for operating the electro-injectors of a diesel engine, comprises an input for connection to a low tension supply, a storage coil for storing energy delivered by the supply, and electronic switching devices for controlling the connection between the input, the storage coil and each of the loads in a predetermined manner to achieve a rapid transfer of current each of the loads selectively a capacitor situated in parallel with the branch circuits containing the loads and connected to the coil and the electronic switching devices, and an electronic control unit. The electronic control unit pilots the electronic switching devices according to a first operative mode in which, to transfer current to one of the loads, the switching devices cause in succession, after the connection the storage coil to the supply, the connection of the storage coil to the capacitor so as to form a resonant circuit, and then the discharge of the resonant circuit into the load.

Abstract: A control circuit which includes a circuit for regulating the time taken to desaturate the switching transistor. This regulating circuit is arranged to control the time for which the transistor is conductive, so that the desaturation time of the transistor is substantially nil when the rate of rotation of the engine is greater than a predetermined value.

Abstract: A strain gauge sensor for sensing stresses and deformations in mechanical members or structures, comprising a support substrate in form of a thin plate, made of an electrically-insulating material, preferably ceramic material, bearing on one face at least one thick-film resistor; said support substrate being adapted to be firmly attached with its other face onto a member or structure of which stresses and deformations are to be locally sensed, so that said stresses or deformations determine through the substrate corresponding deformations of said at least one thick-film resistor.

Abstract: The sensor includes a rigid support and a diaphragm having a peripheral portion fixed by a layer of glue to the support. The central portion of the diaphragm is spaced from the support and, on its surface facing the support, carries at least one thick-film resistor acting as a piezo-resistive transducer. The diaphragm can deform resiliently towards the support when a pressure is exerted on its other surface. The surface of the support which is connected to the diaphragm is flat, and the layer of glue has a calibrated thickness such that the distance between the diaphragm and the surface of the support at rest is substantially equal to the deflection of the diaphragm corresponding to a predetermined maximum pressure measured.

Abstract: In a thick-film pressure sensor comprising a support plate on at least one surface of which are deposited at least one thick-film resistor acting as a piezo-resistive transducer and at least one pair of thick-film conductors acting as rheophores, the at least one thick-film resistor and the thick-film conductors are covered with a protective layer of dielectric material.

Abstract: A method for achieving mechanical and electrical interconnection of first and second bodies of which the first has at least one conductive element its surface intended to face the second and the second has a through-hole for electrical connection provided with a metallic coating intended for electrical connections to the conductive element of the first body includes applying layers of vitreous glue to corresponding surface portions of the first and second bodies. Moreover, a coating of conductive material in a vitreous matrix is deposited by the thick film technique on the surface of the second body intended to face the first, adjacent the through hole with the coating extending at least partly into the hole and electrically connected to the metallic coating of this hole. The bodies are then joined bring the respective layers of glue into contact with each other and the conductive coating of the second body into contact with the conductive element of the first.

Abstract: In order to reapply the fluid operating pressure to the braking members of the wheels after an anti-locking operation has been carried out, a pumping device is provided which are driven by the subatmospheric pressure (vacuum) existing in the inlet manifold of the engine. The application of the braking pressure is controlled by a valve which receives an opening command signal consisting of a train of pulses from a control device. At least one vacuum sensor is provided which generates a monitoring signal indicative of the level of vacuum present in the inlet manifold. The control device causes opening of the valve with a command signal whose average is inversely proportional to the level of the monitoring signal generated by the vacuum sensor.

Abstract: An electrical sensor device, particularly a pressure sensor device, comprises at least one pressure transducer, particularly a thick-film transducer, connected to a monitoring circuit arranged to output an electrical signal which is variable in dependence on the pressure, an interface circuit connected to the monitoring circuit and arranged, in response to the said signal, to present an output resistance which increases or decreases in accordance with a predetermined response curve, on increase in the pressure detected by the transducers.