Abstract: A fail-safe coil ingition dwell control system for an internal combustion engine of the type employing a digital ignition advance computer, wherein the computer computes ignition advance angle data and stores current dwell data. The fail-safe system detects the absence of an ignition spark, as may be caused by a computer failure, and in the event thereof produces a control signal capable of triggering the engine power element, i.e. spark plug, and includes an output switching circuit at the output thereof for switching control of the triggering of the engine power element from the computer to the signal generator circuit in the event of a computer failure.

Abstract: A shaft, the angular position of which is to be detected, equipped with a notched disk one tooth of which has been removed. A position sensor detects the passage of the teeth for a Schmitt trigger with its output connected to the inputs of two monostable multivibrators, to the up-down counter input of a counter, to one input of an AND gate and to the inputs of logic circuits. The held output of the counter is connected to an input of a type D flip-flop connected at its output to the second input of the AND gate.

Abstract: An improved interface circuit for use between variable voltage analog sensors which are measuring physical parameters and a microprocessor which is processing the data relating to such parameters. The interface unit is of the type employing an analog multiplexer, an analog to digital converter, a voltage to frequency converter, a counter for converting frequency to digital data, and a bus adapter for connection to the microprocessor. The inventive improvement relates to providing the multiplexer as a differential multiplexer having two differential voltage outputs and having a sign detector connected thereto. A switching block is connected between the differential voltage outputs and the voltage to frequency converter and also to the sign detector thereby acting as a selector circuit.

Abstract: Device for controlling by means of a current program a plurality of solenoid valves operating independently. Each solenoid is provided with a current flow control circuit having two inputs. The first input receives a first control signal which determines the duration of each actuation of the corresponding solenoid valve. The second input receives a second control signal derived from the first signal and of lesser duration. The current flow control circuit then provides a pull current to actuate the solenoid in response to these input signals.

Abstract: The invention relates to a control device for D.C. motors operating by chopping the supply current. Said device comprises a voltage-frequency converter, a frequency divider, a monostable multivibrator, an analog-digital converter, a pulse down-counter and a bistable flip-flop, arranged to chop the direct current supply by means of a hit or miss control signal of which the cyclic ratio is a linear function of a control voltage U.

Abstract: Device for electronically controlling the ignition of an internal combustion engine comprising a sequencer coupled through a first output to one input of a first binary rate multiplier coupled in turn through a series of parallel-connected inputs to a pressure sensor-converter, the output of said multiplier being connected to one input of another binary rate multiplier connected through a series of parallel-connected inputs to a memory coupled in turn via a set of parallel-connected inputs to a counter connected to the sensor associated with the engine-driven member.

Abstract: An electronic ignition control system for internal combustion engine, notably for motor vehicles, which comprises a rotary member revolving at the engine velocity and provided with at least two reference marks of which the positions correspond to the maximum ignition advance angle and to the minimum ignition advance angle, respectively, said reference marks defining at least one area on said rotary member, a sensor disposed in close vicinity of said rotary member so as to detect the moments of passage of said reference marks and at least one up-and-down counter for counting pulses, said rotary member further comprising a third reference mark separate from the first two reference marks aforesaid so as to define two successive areas (A = 12, 13; B = 13, 14) scanned in succession by said sensor, while a first up-and-down counter positively counts the pulses from a first clock system during the passage of said first area (A) and negatively counts, during the passage of the second area (B), the pulses from a secon

Abstract: The operation of each electromagnetic fuel injector of an internal combustion engine is controlled so that when an energizing current is caused to flow from the battery of the engine through the coil of the fuel injector, the time taken for the current to reach its full value is controlled electronically so that it is a constant irrespective of the battery voltage but no shorter than would naturally result if the battery were to deliver its predicted lowest voltage directly to the coil, the necessary control being obtained by generating a constant electric current and using it to charge a capacitor to a predetermined voltage, comparing the voltage of the capacitor with a voltage which is proportional to the energizing current flowing through the coil, and controlling the build up time of the energizing current so that it is equal to the time taken to charge the capacitor, this being constant.

Abstract: An apparatus and method for detecting faulty combustion in an internal combustion engine. The series combination of a voltage source and a resistor are connected across the electrodes of a spark plug and the magnitude and shape of the voltage waveform across the resistor is indicative of whether or not a spark has occurred and whether or not combustion has occurred. An electronic processing circuit is provided for actuating an alarm or affecting the operations of some part of the engine or automobile when it is determined either that a spark has not occurred at the proper time or that a predetermined minimum number of consecutive sparks has occurred without the occurrence of combustion.