Abstract: The idling speed of an internal combustion engine is regulated with the use of an electronic control unit arranged to generate a signal for correcting the ignition advance and a signal for varying the piloting of a solenoid valve provided in a duct which by-passes a throttle valve which controls the air supply to the engine. For this purpose, the electronic unit acquires the instantaneous speed of the engine and the air pressure in the inlet manifold by means of sensors. The electronic unit implements an LQI (linear-quadratic-integral) type of control based on a linear mathematical model of the engine.

Abstract: The method and apparatus allows the detection and indication of anomalies in the operation of the ignition system of an internal combustion engine including a plurality of spark plugs, each of which receives a periodic high-voltage pulse output by a high-voltage generator in operation. The method includes the steps of:detecting the pulses generated by the high-voltage generator,comparing the peak values of each pulse detected with first and second threshold values, andproducing a perceptible signal when the peak values of the high-voltage pulses fall outside the acceptable range defined between the threshold values.

Abstract: The device essentially comprises an auxiliary coil for storing the ignition energy, and a transformer for each spark plug. It is thus possible to prepolarize each transformer in the proper sequence with a current opposite that applied during discharge, whereby a transformer of smaller dimensions can be associated with each spark plug while the performance remains unchanged from that of conventional systems.

Abstract: The device is of the type comprising for each engine spark plug a transformer with a secondary winding to be connected to the respective spark plug and a primary winding connected to the output of a power stage able to provide an ON-OFF signal for controlling the transformer. The device also comprises a damping network and, interposed between the network and the output of the power stage, unidirectional connection means which connect said network to the output of the power stage each time the signal present at said output switches from an OFF condition to an ON condition.

Abstract: The spark plugs (1a, 1b; 2a, 2b; 3a, 3b; 4a, 4b) associated with each cylinder (1, 2, 3, 4) are supplied by respective ignition coils (21, 22, 23, 24) preferably mounted on the plugs themselves.

Abstract: A signalling device for providing indications of the fuel consumption of an internal combustion engine of a motor vehicle comprises first and second sensor means which provide electrical signals indicative of the rate of rotation of the engine and the speed of the motor vehicle, respectively. The first sensor means are connected to a first processing circuit which provides an information signal proportional to the rate of rotation of the engine. A second processing circuit connected to the second sensor means provides a second information signal which is directly proportional to the speed of the vehicle when this speed is less than a predetermined value and which is zero when the speed is greater than the predetermined value. A first adding circuit is connected to the processing circuits and provides a sum signal corresponding to the sum of the first and second information signals. The amplitude of this first sum signal is indicative of the fuel consumption.

Abstract: A device for automatic adjustment of the frequency of activation of a motor vehicle windscreen wiper driven by a motor is described. The main characteristic of the device lies in the fact that it comprises circuit means which control the frequency of activation as a function of the quantity of water present on the surface which is wiped by the windscreen wiper.

Abstract: An apparatus for carrying out the calibration of engines having a Bosch L-Jetronic electronic injection apparatus which is provided with an electronic control unit connected to a "lambda" probe inserted in the exhaust pipe for the closed loop control for carburetion includes a circuit for determining the difference between the value of a correction signal when the probe is switched into the circuit and the value of the correction signal when the probe is switched out of the circuit and a display device for providing a visual display of the difference.

Abstract: The period of opening of a solenoid-operated fuel injector is stabilized against variation of vehicle battery voltage by computing the period of injector opening from the instant of a discontinuity present in each rise of the solenoid energizing current. The discontinuity is detected and differentiated to form one input to a comparator, the other input of which is supplemented from the vehicle battery through a Zener diode so that the comparison threshold of the comparator increases as the battery voltage increases. The comparator is automatically switched off in the absence of a solenoid energizing current.

Abstract: The quantity of air inducted in a four cylinder Otto engine with fuel injection and an inlet throttle for each cylinder is determined by indirect measurement, unaffected by atmospheric pressure variations. The induction air pressure is measured by a transducer located between one of the throttles and its associated cylinder inlet valve, and the pressure is sampled, using an electronic gating system responsive to engine speed, within a precisely defined range (preferably 15.degree.-25.degree. after bottom dead center) of engine crankshaft angle.

Abstract: In order to stabilize the open time of an electromagnetic fuel injector against variation of vehicle battery voltage, first and second threshold values of solenoid current for opening and closing of the injector are predetermined experimentally, the duration of the injection control signal being determined from the time the first current threshold is reached. The battery voltage dependent delay between the end of the injection control signal and the reaching of the second current threshold as the solenoid current decays is subtracted from the duration of the injector opening control signal for the subsequent injection cycle.