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: This invention relates to a number of improvements in ignition systems of spark ignition engines. A detector is employed to sense the first or "breakdown" phase of spark discharge across the spark plug which causes a short duration high current flow across the plug gap. The detection of the breakdown current enables control over a number of ignition system functions. A pulse transformer is used which enables extremely short duration energization of the spark plug at controllable voltages. The existence of end gas auto-ignition is detected by energizing the spark plug during a period of the operating cycle after top dead center of piston travel. Since the threshold voltage necessary to generate spark discharge at the plug differs in conditions where auto-ignition is occurring versus ordinary combustion, sensing of plug breakdown during such energization provides a means of detecting the occurrence of auto-ignition.

Abstract: A magneto ignition system includes a rotating magnet driven past a primary winding for firing the engine. The magneto generates a speed dependent signal having a following current pulse and a leading current pulse of a smaller amplitude than the following pulse. A Darlington power transistor has a collector connected in series with a voltage dropping resistor or diode to the winding. A resistor bias circuit connects the primary winding to the input of the power transistor. A cut-off transistor is connected to by-pass the bias circuit of the Darlington power transistor and thereby generate a pulse in the primary winding. A timing capacitor is connected to the primary winding in series with a diode and charging resistor. A control transistor has its input circuit connected between the timing capacitor and the resistors of the bias circuit.

Abstract: A twin ignition plug control system for an internal combustion engine by which two point ignition is switched to one-point ignition only when engine load is heavy and the engine is not being warmed-up. Since the control system according to the present invention is so configured that many elements or sections can be used in common with a convention fuel injection valve control system, without providing various sensors or detectors such as a vacuum sensor disposed with an intake manifold for detecting engine load, a clutch switch or a neutral switch for detecting engine idling, etc., it is possible to simplify the twin ignition plug control system and thus reduce the manufacturing cost. When a microcomputer is incorporated within the fuel injection valve control system, in particular, the present invention is advantageous.

Abstract: An ignition system for a multi-cylinder internal combustion engine eliminates high-voltage cables and a mechanical distributor in order to reduce electrical power losses due to joule effect caused mainly by the high voltage circuit, comprises a plurality of ignition coils and plugs, one provided for each cylinder, a distribution unit for distributing advance-angle control signals into the respective cylinders, and a booster for boosting the supply voltage in order to reduce the size of the ignition coil, in addition to the conventional ignition system. Furthermore, the ignition coil can be built integrally with the ignition plug for eliminating high-voltage cables connected between coil and plug.

Abstract: An ignition coil control circuit compares the coil input current with a reference level, and the duty ratio of the output current is altered accordingly. The reference level is raised during cold weather operations, raising the duty ratio. Once the operating temperature of the engine rises above a predetermined level, a detector circuit activates a control signal generator which lowers the reference level received by the comparator to lower the duty ratio accordingly.

Abstract: Energizing interval of an ignition coil, which is basically determined on the basis of the rotational speed of an engine, is corrected by adding thereto an extension amount which is either a function of the rotational speed of the engine or a given upper limit value at the rotational speed of the engine when accelerating condition is detected. Thus, the ignition coil is supplied with a primary winding current for a desired interval even during acceleration so that sufficient ignition voltage will be produced to properly ignite air/fuel mixture in engine cylinders. The extended energizing interval is then reduced stepwise to provide normal energizing interval during engine operations other than acceleration.

Abstract: In an ignition system for an internal combustion engine in which the flow of a primary winding energizing current is switched on and off in synchronism with the rotation of the engine and a high voltage is induced in the secondary winding upon switching off of the energizing current, an energizing current is supplied again at around the top dead center of each cylinder and then decreased gradually and interrupted in accordance with a sawtooth waveform whose voltage attains a predetermined potential at around the top dead center and then decreases gradually.

Abstract: An electronic engine control system has a pressure sensor communicating both to the intake manifold and the ambient air via a valve means selectively introducing either the intake vacuum or the ambient air into the pressure sensor. The control system further includes a valve control means for controlling the operation of the valve means for selectively communicating the pressure sensor to the intake manifold and the ambient air. The valve control means is incorporated in a controller for determining the control value and adapted to produce a control signal to be supplied to the valve means in order to electrically control the valve motion.

Abstract: An internal combustion engine and method of operating it that improves combustion efficiency, fuel economy and exhaust emission during low speed running. The engine is equipped with a relatively conventional main induction system and an auxiliary induction system having a substantially smaller cross sectional area for delivering a charge to the chambers of the engine at a high velocity to improve turbulence and combustion efficiency. A control valve arrangement is incorporated so that the idle and low speed requirements are supplied through the auxiliary induction system and the medium and higher load charge requirements are supplied primarily through the main induction system. An exhaust gas recirculating system is incorporated for reintroducing exhaust gases to the combustion chamber so as to reduce the emissions of nitrous oxide.

Abstract: An ignition timing correcting system for generating a reference signal at a reference angular position of a rotating internal combustion engine, and having an ignition signal leading it by a constant phase. In response to a control signal from a movable tap on a potentiometer, the ignition signal is retarded in phase to form a retarded ignition signal. The phase comparison of the two signals produces an advance or a retardation signal formed of a pulse train having a pulse width corresponding to the phase difference there-between.

Abstract: An ignition system for internal combustion engines of the type in which after the energizing current flow to the primary winding of an ignition coil has been interrupted and an ignition spark generating high voltage has been produced in the secondary winding, the primary winding is energized again to interrupt the ignition spark. The ignition spark is interrupted at around the TDC only when the engine is at high speed operating conditions and the deenergizing current in the primary winding is not interrupted in a moment but decreased gradually. Also, the ignition spark is interrupted only when the ignition spark is to continue beyond the top dead center.

Abstract: An ignition system for the internal combustion engine comprising a high voltage circuit for generating a spark, having the primary and secondary windings. In response to a first signal, the current in the primary winding is cut off thereby to generate a high voltage at the secondary winding. In response to a subsequent second signal, the primary winding is shorted thereby to cut off the high voltage thus far generated in the secondary winding, thus properly regulating the duration of the spark generated.

Abstract: An exhaust gas recirculation control valve is positioned by a diaphragm responsive to the difference between a control pressure and atmospheric pressure. The control pressure is adjusted so that its absolute value is maintained equal to a command which varies with engine operating conditions, whereby exhaust gas recirculation is reduced automatically upon a decrease in atmospheric pressure.

Abstract: An EGR valve control signal developed by the EGR modulator circuit for controlling the EGR valve is combined in a feedback loop with a signal representative of an engine combustion condition, e.g. engine knock to modify ignition timing through advance or retard.

Abstract: A control system for an internal combustion engine comprises a transducer for issuing a signal representative of combustion pressure in a combustion chamber, a unit consisting of a bandpass filter and a wave-form shaping circuit for issuing a signal representative of existing combustion timing of the combustion chamber by processing the signal from the transducer for detection of rapid increase of the combustion pressure; a reference timing circuit for issuing a signal representative of a predetermined reference combustion timing of the combustion chamber in accordance with operation modes of the engine, a comparator circuit for issuing a signal representative of a difference between the signal from the unit and the signal from the reference timing circuit, and a unit consisting of a discriminating circuit and an actuator driving circuit for controlling the ignition timing, the air-fuel ratio of air-fuel mixture and the amount of exhaust gas recirculated into the intake system of the engine, by processing the

Abstract: When the engine accelerates, the angle over which the ignition switch is closed prior to initiating the spark is automatically increased. Acceleration of the engine is detected by a comparator which compares the value of a speed-dependent signal in sequential cycles and initiate closure of the ignition switch if a predetermined difference is exceeded between the so-compared signals at a predetermined time in the cycle. Under static or decelerating conditions, the speed-dependent signal is compared, in each cycle, to the output of an integrator circuit. The integrator circuit integrates in a first direction at a first rate up to the above-mentioned predetermined time in the cycle and in the opposite direction at a second predetermined rate for the remainder of the cycle. The average value of the integrator output signal corresponds to the engine speed. When the so-compared signals are equal, the second comparator furnishes an output signal which closes the ignition switch.

Abstract: An engine ignition system includes a throttle sensor for detecting the position of a throttle valve. A control circuit is responsive to the detected throttle signal as well as the signals from other negative pressure and engine rpm sensors to generate a spark plug discharge start signal and a discharge stop signal. A high voltage generator supplies a high voltage to the respective spark plugs during the time interval between the time that the discharge start signal is generated and the time that the discharge stop signal is generated.

Abstract: An improved ignition circuit for internal combustion engines is described herein, in which a diode is connected in parallel to a primary winding of an ignition coil of a magneto, and a composite transistor circuit consisting of two transistors whose forward direction is directed in the reverse direction of said diode, is connected across said primary winding at its collector and emitter, whereby overheating of said transistors caused by a primary reverse current of said magneto ignition coil flowing into the transistors can be prevented and also proper ignition timing can be maintained.