Abstract: An electronic ignition system for an internal combustion engine. In a first embodiment an input pulse is generated at the same point in each revolution of the engine. Clock pulses at a first pulse rate are counted between consecutive input pulses. The resulting count signal is transferred to a down counter which, between the consecutive input pulses, counts down at a faster rate. For an eight cylinder engine this faster rate is four times the first pulse rate, for a six cylinder engine it is three times the first pulse rate, and for a four cylinder engine it is twice the first pulse rate. In a second embodiment a computed count signal is reset into a down counter which is then counted down. In each embodiment, when the down counter reaches its zero count level the count signal is again preset into it so that it recycles. Each time the down counter passes a pre-selected count level, an output pulse is generated.

Abstract: To prevent malfunction due to misfire of a distributorless internal combustion engine (ICE), in which two spark plugs (20, 21; 27, 28) are connected to the same output terminals of the secondary (9) of an ignition coil through respectively reversely polarized diodes (18, 19; 25, 26), the polarity of the output spark pulse at the terminals (17, 24) of the ignition coil determining the identity of the spark plugs which have spark discharges occur thereacross due to the polarization of the serially connected diodes, additional diodes (22, 23; 29, 30) of the high-voltage type are connected in parallel across each of the spark plugs (20, 21; 27, 28) and polarized in reverse polarity with respect to the serially connected diodes, connected to the respective spark plugs, to thereby short-circuit current through the additional diode upon passage of energy by a serially connected diode in reverse direction due to malfunctioning, for example alloying-through or at least partial short-circuiting of the respective serial

Abstract: An ignition timing control system for an internal combustion engine (18) varies the timing of a magneto (14) in accordance with a pre-programmed ignition advance schedule. An optical pick-up (22) senses the passage of slots (26) in a disc (24) which is rotated at the speed of a distributor (16) and produces constant angular width reference pulses corresponding to fixed ignition timing in the engine's cylinders (13). A magnetic pick-up (36) detects incremental rotation of the engine's crankshaft (33) and produces timing control signals proportional to engine speed. The timing control signals and reference pulses are converted to a multi-bit data word which is used to synthesize an analog control function representing variable ignition timing using a pre-programmed digital to analog converter (58).

Abstract: An ignition circuit for an internal combustion engine has a flip-flop circuit (8), operated by narrow width output pulses (c, d) of an ignition timing computing circuit (4), thereby to distribute output pulses of a duty cycle control circuit (5) to ignition coils; thus a large advance of ignition pulses is obtainable.

Abstract: In a method and apparatus for controlling fuel injection in an internal-combustion engine, crankshaft angle signals and cylinder discrimination signals are produced by a crankshaft angle sensor, and the signal for execution of the first injection of fuel is calculated in a control circuit on the basis of the crankshaft angle signals and the cylinder discrimination signals so that the first explosion of the air-fuel mixture takes place within one rotation of the crankshaft of the engine.

Abstract: A fuel supply control method for controlling the fuel supply to an internal combustion engine at deceleration, wherein the valve opening of a throttle valve of the engine is detected while the throttle valve is being closed and each time each pulse of a predetermined sampling signal is generated, a variation in the same valve opening occurring between adjacent pulses of the sampling signal is determined as a control parameter value, and the quantity of fuel being supplied to the engine is reduced by an amount corresponding to the control parameter value.

Abstract: An N cylinder internal combustion engine plasma ignition system comprises a DC-DC converter for boosting low DC voltage to high DC voltage. Each of N ignition energy charging circuits includes a first capacitor connected between the DC-DC converter and ground via first and second diodes. The capacitor is charged by the DC-DC converter. Each of N reverse blocked thyristors connected to a junction of the first diode and first capacitor selectively grounds an electrode of the corresponding first capacitor to discharge ignition energy stored in the first capacitor. For each cylinder a transformer connected between the first capacitor and a spark plug boosts and feeds the discharged energy to the plug. One end of the transformer primary winding is grounded via a second capacitor to generate a damped oscillation when the corresponding thyristor grounds the first capacitor.

Abstract: To provide ignition energy to respective spark plugs of a multi-cylinder internal combustion engine (ICE) without a distributor, winding groups, each including a primary and secondary winding, are located on respective core portions of an iron core, which core portions are coupled together by zones (a, b, c) of high magnetic reluctance, or low magnetic flux conductivity; the winding groups can be located on L cores (16, 17) with two high-reluctance gaps between the ends of the facing L cores (FIG. 1) or on a common U core (28, 30, 29) with a cross yoke (31) spaced from the ends of the legs of the U.

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 input/output unit modifiable engine ignition control apparatus for controlling ignition timing for engine cylinders at optimum values based on reference position pulses, crank angle pulses generated and a vacuum signal produced by reference position sensors, a crank angle sensor and a vacuum sensor mounted in an engine. The engine ignition control apparatus is divided into an input-output unit and a control unit. The control unit having a control capacity for an engine having a maximum number of the sensors and engine cylinders, so that the control unit can be shared by a variety of engines for their ignition control simply by changing the input-output unit.

Abstract: A control unit modifiable engine ignition control apparatus for controlling ignition timing optimally for each cylinder by processing reference position pulses, crank angle pulses and a vacuum signal generated by a reference position sensor, a crank angle sensor and a vacuum sensor which are mounted on the engine. The engine ignition control apparatus is divided into an input-output section including an input-output unit and a controller comprising a single or a combination of control units each having a minimum capacity to control a single ignition coil.

Abstract: An ignition system for an internal combustion engine having a plurality of engine cylinders, wherein ignition coil and spark plug are integrally assembled into each engine cylinder so as to eliminate an ignition energy transmission loss, a DC-DC converter for boosting a low DC voltage into a high DC voltage is provided for applying the high DC voltage into each secondary winding of the ignition coils for achieving an efficient ignition of air-fuel mixture, the application of the high DC voltage being enabled according to a particular engine operating condition, e.g., engine low speed and light engine load condition, and the ignition energy being varied according to an engine operating condition by changing the pulsewidth of the ignition pulse signal to be fed into a cylinder judging circuit which judges the spark plug to be ignited and distributes the ignition pulse signal into the related circuit of the corresponding ignition coil.

Abstract: An engine ignition interpolation apparatus including three reference position sensors, a single crank angle sensor and a counter resettable by outputs from the reference position sensors and used for counting output pulses from said crank angle sensor. Also included are a decoder for generating an output when the counter produces a count output which exceeds a preset value, flip-flops connected respectively to the reference position sensors in a ring arrangement and triggerable by the outputs from the reference position sensors for synchronous operation therewith, and a logic circuit for seeking conformity between the output from the decoder and set outputs from the flip-flops to produce a quasi or replacement pulse for one of the reference position sensors which fails to produce an output, thereby interpolating a reference position pulse.

Abstract: A distributorless ignition system of an internal combustion engine has a supplementary spark energy module to increase spark energy. Two ignition coils each have secondary coils with split secondary center taps. Each of the primary windings is coupled to its own ignition module. The supplementary spark energy module is coupled to each of the split secondary center taps. A pair of spark plugs is coupled to one of the secondary windings and another pair of spark plugs is coupled to the other secondary winding.

Abstract: An engine ignition control circuit includes a crank angle sensor and two reference position sensors. The engine ignition control circuit also includes an ignition timing control unit generating primary ignition signals and a replacement ignition signal generator device. The control circuit further includes a crank angle monitoring circuit which detects the failure of the crank angle sensor and generates a malfunction signal. The malfunction signal controls a data selector which outputs either the primary ignition signals or the replacement ignition signals to drivers and ignition coils for the engine.

Abstract: Described is an electronic ignition timing control device in which the low voltage distribution system is resorted to in place of the high voltage system making use of a distributor. There is provided angle sensor means the output of which is initiated at an angle advanced from the maximum ignition advance angle of each engine cylinder and terminated at the start-time ignition angle. The ignition time is controlled in terms of a lag from the angle advanced from the maximum ignition advance angle of each cylinder at which the angle sensor output is initiated.

Abstract: A distributorless ignition system of an internal combustion engine has a supplementary spark energy module to increase spark energy. Two ignition coils each have secondary coils with split secondary center taps. Each of the primary windings is coupled to its own ignition module. The supplementary spark energy module is coupled to each of the split secondary center taps. A pair of spark plugs is coupled to one of the secondary windings and another pair of spark plugs is coupled to the other secondary winding.

Abstract: A distributorless ignition system in which a primary current alternately changing in its flowing direction is supplied to the primary winding of an ignition coil to induce a high secondary voltage alternately changing in polarity across the secondary winding of the ignition coil, and the induced voltage is sequentially distributed through a plurality of rectifiers such as diodes to a plurality of associated spark plugs thereby sequentially causing jumping of a spark across the spark gap of the spark plugs. An apparatus for mounting such a distributorless ignition system is also disclosed.

Abstract: A distributorless ignition system of an internal combustion engine has a supplementary spark energy module to increase spark energy. Two ignition coils each have secondary coils with split secondary center taps. Each of the primary windings is coupled to its own ignition module. The supplementary spark energy module is coupled to each of the split secondary center taps. A pair of spark plugs is coupled to one of the secondary windings and another pair of spark plugs is coupled to the other secondary winding.

Abstract: An ignition system for an internal combustion engine having a flywheel coupled to a plurality of bipolar magnets and a camshaft coupled to a unipolar magnet. A bipolar Hall sensor is positioned adjacent the flywheel for detecting passage of the bipolar magnets and generating a square wave signal to provide camshaft position. A unipolar Hall sensor is positioned adjacent the camshaft for detecting the passage of the unipolar magnet and generating a square wave signal to provide a reference signal indicating a known position of one cylinder.

Abstract: An engine ignition system connected between an engine crank and ignition coils includes a reference position signal generating device having reference position sensors, and a crank angle sensing device. The ignition system also includes a signal processing device which receives both the reference position signals and crank angle signals, and when one of the reference position signals is absent continues to generate ignition control signals which activate the ignition coils. The signal processing device includes a counter which counts the crank angle signals and which is reset by the reference position signals, and a decoder which produces a signal when a count value reaches a predetermined count. The signal processing device also includes a logic circuit and a flip-flop for producing either primary ignition control signals or replacement ignition control signals. The replacement ignition control signals are generated when one of the reference position signals is absent.

Abstract: A plasma ignition system for an internal combustion engine which varies a discharge time of a plasma ignition energy charged capacitor according to the engine operating condition, e.g., the current engine speed.

Abstract: A plasma ignition system for an engine having any number of engine cylinders, which comprises: (A) a plurality of plasma ignition plugs each mounted within a corresponding engine cylinder; (B) a first power supply unit for supplying a first electric power into each plasma ignition plug so as to generate a spark discharge within each plasma ignition plug; (C) a first switching circuit for sequentially connecting the first power supply unit to each plasma ignition plug according to a predetermined ignition order; (D) a second power supply unit for supplying a second electric power into each plasma ignition plug so as to generate a high-temperature plasma gas within each plasma ignition plug; and (E) a second switching circuit for sequentially connecting two of the plasma ignition plugs within the respective engine cylinders, one engine cylinder being at the start of an explosion stroke and the other engine cylinder being at almost end of an exhaust stroke, in a predetermined delay after the occurrence of the sp

Abstract: An ignition system for an internal combustion engine, wherein separate ignition transformers are mounted directly on respective spark plugs and an A.C. drive signal is applied to the ignition transformers sequentially in accordance with engine timing to fire the spark plugs sequentially. The A.C. drive signal is applied to each of the ignition transformers by means of a leakage transformer whereby ignition currents are maintained at a relatively low level after initiation of the ignition discharge across the spark plug electrodes. In one embodiment, each ignition transformer is composed of plural individual transformers disposed in a planetary arrangement around an axis defined by the respective spark plug. Each of these individual transformers includes at least one secondary winding and at least one primary winding wound on a respective core, with each of the secondary windings mounted in series across the electrodes of the spark plug.

Abstract: What is disclosed is an ignition timing control system for internal combustion engine wherein an angular signal is generated at a predetermined crank position. This angular signal is fed into an integrator which is made operative to repeat its charging and discharging cycles with a constant current so as to provide an output which is retarded or advanced of the crank position in accordance with the rise and fall of the r.p.m. of the engine.

Abstract: An ignition position controlling apparatus for a multicylinder internal combustion engine is disclosed which is capable of generating clock pulses and cylinder discriminating signals for detecting proper angular positions necessary to determine the ignition positions of cylinders of the engine using an inductor-type signal generator simple in construction which includes signal generating means in number corresponding to the number of cylinders of the engine and a single disc-like toothed inductor.

Abstract: An ignition system for a multi-cylinder internal combustion engine having a spark plug within each engine cylinder, wherein a single DC-DC converter is provided and a high-voltage withstanding characteristic capacitor is provided for each spark plug. The capacitor charges to the high DC output voltage of the DC-DC converter and operatively supplies the high DC voltage via a boosting transformer into the corresponding spark plug at a predetermined ignition timing. The amount of the discharge energy being varied according to the pulse width of an input signal of each switching circuit which operates to supply the charged high DC voltage of the capacitor into the corresponding spark plug, the pulse width being varied according to various engine operating conditions.

Abstract: A high voltage generating circuit for an automotive ignition system, wherein a current control circuit is provided in series with an automotive battery and a controlled high frequency switch to generate a high frequency, linearly increasing ignition current across the electrodes of the spark plugs of an internal combustion engine in order to accommodate shifts in the spark plug sustaining voltage which may occur due to changes in operating conditions. In a preferred embodiment, a DC-DC converter is inserted in series between the battery and the current control circuit to step-up the voltage applied to the current control circuit.

Abstract: A plasma ignition system for an internal combustion engine having a plasma ignition plug within each of the engine cylinders, which comprises: (a) a low DC voltage supply such as a vehicle battery; (b) a high surge voltage generator which generates and distributes a high surge voltage having a negative peak value of about minus 15 kilovolts into one of the plasma ignition plugs according to a predetermined ignition order so as to generate a spark discharge at the plasma ignition plug; (c) a DC-DC converter which boosts the low DC voltage sent from the low DC voltage supply to a high DC voltage; (d) a plurality of plasma ignition energy charging means each of which charges the high DC voltage supplied from the DC-DC converter; (e) a plurality of thyristors each for connecting the plasma ignition energy charging means to the corresponding plasma ignition energy charging means to the corresponding plasma ignition plug in response to a first trigger signal applied thereat; (f) a trigger signal generator which gen

Abstract: An ignition system for an internal combustion engine is disclosed which includes a separate ignition transformer for each spark plug in the engine. Each of the ignition transformers is enabled by means of signals produced by a crankshaft position sensor. Pulsating DC currents are then caused to flow in the primary windings of the ignition transformer thereby inducing a high voltage into a secondary winding of the transformer. A combination ignition transformer and spark plug cover is also disclosed.

Abstract: An electronic ignition and fuel control system is provided for internal combustion automotive vehicle engines which are of the spark ignition type. The ignition and fuel control system of this invention includes an electronic timing and detector circuit, distributor circuit, clock and command circuit, ignition power circuit and air-fuel control circuit. The clock and command circuit responds to selected positioning of an accelerator control element to provide either a plurality of firing pulses to the engine ignitors in an acceleration mode of operation, or to provide single pulse firing in the case of steady state operation or a deceleration mode of operation. In the ignition and power circuit, individual coils are provided for generating a high voltage firing pulse applied to each of the ignitors that are interconnected with the respective coil.

Abstract: A plasma ignition system for an internal combustion engine, which comprises: (a) a low DC voltage power supply; (b) a DC-DC converter which converts a low DC voltage from the low DC voltage supply to the corresponding AC voltage and inverts the AC voltage to a high DC voltage; (c) a plurality of plasma ignition plugs each located within one of the cylinders; (d) a plurality of first capacitors each for changing the high DC voltage received from the DC-DC converter; (e) a plurality of photosensitive switching elements each connected between each corresponding first capacitor and ground and which turns on to apply the plasma ignition energy charged within the corresponding first capacitor to the corresponding plasma ignition plug at a predetermined timing; (f) a plurality of voltage-boosting transformers each having a common terminal of primary and secondary windings connected to one terminal of each corresponding plasma ignition energy capacitor and another terminal of the primary winding connected to the corr

Abstract: A distributor for an ignition system that includes a plurality of optical switches (20) and a rotating member (40) having two windows (41, 42) spaced 180 degrees apart so that each switch is activated twice for each revolution of the distributor shaft. The distributor requires only as many optically coupled switches (20) as there are cylinders.

Abstract: Information is derived from two given sets of sensor output pulses relating to crankshaft position for use in determining the proper cylinder to be fired, the spark time and the dwell. The spark is enabled only after the crankshaft position is known, and noise, including the spark itself, is prevented from interfering with the system operation.

Abstract: An ignition system for an internal combustion engine is disclosed which includes a separate ignition transformer for each spark plug in the engine. Each of the ignition transformers is enabled by means of signals produced by a crankshaft position sensor. Pulsating DC currents are then caused to flow in the primary windings of the ignition transformer thereby inducing a high voltage into a secondary winding of the transformer. A combination ignition transformer and spark plug cover is also disclosed.

Abstract: The circuit determines which cylinder is to be fired and continually updates the determination so that the circuit recovers immediately from any false detect and responds to any change of engine condition. The dwell timing is derived from sensors adjacent the flywheel and, to achieve the widest possible range of advance angles, the use of certain sensor-derived signals is delayed until after spark.

Abstract: A four-cylinder engine control system (10) for controlling the functions of ignition or fuel injection is disclosed. The control system includes cylinder identification apparatus (30, 50, 60) which operates in conjunction with a rotary member (11) rotated by the engine crankshaft having timing projections (14, 17) corresponding to specific rotational positions of the crankshaft. A pair of fixed sensors (20, 21) sense the passage of the timing projections and provide corresponding signals to an engine timing calculation and control circuit (40) which provides control signals that are sequentially selectively routed to control ignition and/or fuel injection of the engine cylinders in a predetermined sequence. One timing projection (14) comprises two individual radial extensions (15, 16) whereas another comprises a single extension (17).

Abstract: A ferrous disk is rotatably driven by an internal combustion engine shaft. The disk has outer and inner circular rims projecting outwardly from one side thereof. The outer rim has two arcuate notches of predetermined arcuate length and position and the inner rim has three arcuate notches of predetermined arcuate length and position. A permanent magnet is mounted between and radially spaced from two Hall-effect sensor devices in fixed relation to the shaft axis such that the outer rim passes between one Hall-effect device and the magnet and the second rim passes between the second Hall-effect device and the magnet as the shaft is rotated. The notches are so positioned to provide four separate two digit binary outputs to a microcomputer that provides output signals to ignition coil drivers for the spark ignition devices of the engine and provides spark advancement and coil dwell time variation in accordance with shaft rotational speed and other engine operating conditions.

Abstract: A plasma ignition system for an internal combustion engine which can prevent irregular ignition when the insulation between the electrodes of the spark plug deteriorates due to carbon on the electrodes, and further can prevent electrical noise from being emitted. The system according to the present invention comprises a plasma ignition energy storing condenser, a plurality of switching units, and boosting transformers one each for each of the engine cylinders. In this system, a high tension is generated at the secondary coil of the boosting transformer to generate a spark between the electrodes of the plug and subsequently a large current is passed through the electrodes by the remaining energy stored in the condenser.

Abstract: A plasma ignition system for an internal combustion engine which can prevent irregular ignition when the insulation between the electrodes of the spark plug deteriorates due to carbon on the electrodes, and further can prevent electrical noise from being emitted. The system according to the present invention comprises a plurality of independent plasma ignition energy storing condensers, switching units, and boosting transformers one each for each of the engine cylinder. In this system, a high tension is generated at the secondary coil of the boosting transformer to generate a spark between the electrodes of the plug and subsequently a large current is passed through the electrodes by the remaining energy stored in the condenser.

Abstract: An apparatus for generating signals to control the firing of spark plugs or the operation of a fuel injection distributor for an internal combustion engine having multiple cylinders utilizes sensors that scan markings on the crankshaft and camshaft and an evaluating circuit to develop such control signals.

Abstract: An ignition device for multi-cylinder internal-combustion engines comprising at least one spark plug for each cylinder. Each spark plug is arranged in the secondary circuit of an ignition transformer. The primary circuits of the ignition transformers are connectable with a source of energy by an ignition distributing circuit.

Abstract: An internal combustion engine with M cylinders having an electronic ignition system, a pistons position sensor having a set of M+1 identical conductive members, which are synchronous with rotation of the engine's crankshaft. M of the conductive members are regularly spaced. Two fixed detectors adjacent the rotating members sense the members and supply identical electrical signals. The detectors are spaced to provide the signals out of phase by an amount that is substantially higher than the maximum ignition advance of the engine. Electronic circuits process the signals from the two detectors, include a first circuit that supplies a synchronization signal for the cycle igniting the engine, and a second circuit, which supplies two representative synchronization signals of the static advance and of the maximum dynamic advance during ignition.

Abstract: An ignition initiating signal is developed from the fuel injection nozzle valve of an internal combustion engine. The valve is actuated by fuel pressure which creates an insulating layer at the valve so that when the valve is unseated an electrical circuit is broken to create the ignition initiating signal. And, electrical circuit means are included which limit the voltage applied and the current flow at the valve seat in order to avoid breakdown of the fuel insulating layer and pitting of the valve seat.

Abstract: Electromechanical sensing means comprising first of a set of members all of them substantially identical, arranged on an element turning synchronously with the engine's rotation and, second, of a pair of fixed detectors, placed in a protective casing for the turning element; the set of members including regularly spaced main members, in a number proportional to the number of the engine's cylinders, and at least one auxiliary member displaced at an angle .phi..sub.D at least equal to the lead angle .phi..sub.A to be controlled; the pair of detectors being positioned with regard to the course of the members and the relative angular interval in the two detectors being equal to the angle .phi..sub.

Abstract: A contactless ignition system for use with an internal combustion engine has at least one pulser adapted to detect predetermined maximum and minimum advance angular positions of ignition timing. A first triangular wave form having a first rising gradient and a second triangular wave form having a second rising gradient are formed based on the output of the pulser. When a voltage representative of sum of the first triangular wave form and a reference voltage of a fixed level and the second triangular wave form coincide with each other, an advanced ignition signal of ignition timing is produced, whereby substantially constant advance angles are maintained within low speed range and high speed range of the engine and an advance angle at intermediate speeds of the engine is so controlled as to be proportional to the number of rotations of the engine.

Abstract: A breakerless distributor for an internal combustion engine ignition system in which a number of light emitting diodes (LEDs) (73, 75, 77, 79) equal to the number of engine cylinders are connected in series for simultaneous energization by the timing pulses. A phototransistor (83, 85, 87, 89) arranged in spaced, confronting relationship to each LED is connected to a silicon controlled rectifier (95) which triggers the energizing circuit (7, 9, 11, 13) for an individual spark plug (103) each time the phototransistor is turned on by emissions from its associated LED.

Abstract: An internal combustion engine crankshaft reference signal pulse corresponding to a selected one engine cylinder pair and a series of crankshaft position signal pulses are generated during each crankshaft revolution and a crankshaft reference signal pulse corresponding to each other engine cylinder pair is synthesized during each crankshaft revolution. In response to each crankshft reference signal pulse and the subsequent crankshaft position signal pulses there is produced an ignition dwell signal effective to initiate ignition coil primary winding energization and later an ignition spark event signal that is effective to terminate ignition coil primary winding energization to thereby produce an ignition spark potential at the engine crankshaft angle at which an ignition spark event is to occur as calculated by an associated external data processor unit.

Abstract: An electronic ignition system for an internal combustion engine allowing precise control of the instant of ignition of the air-fuel mixture, in which the mechanical components, particularly the high voltage distributor, are eliminated. This system comprises a transducer delivering two cyclic sequences of signals synchronous with the position of the stroke of the pistons, means for controlling the instant of emission of the sparks in all the operational states of the engine, distributing means supplying release signals to spark generators connected to the spark plugs. Application to internal combustion engines, particularly to multicylinder engines.

Abstract: An ignition device for an internal combustion engine comprises two signal generator coils for generating the output having steep variation from positive (or negative) peak value to negative (or positive) peak value by corresponding to the ignition timing of the engine. The two signal coils are serially connected in reverse polarity and the output terminals of the generator coils are connected in parallel to a circuit in which two rectifying elements are serially connected in reverse polarity. The joint between the two generator coils is connected to the joint between the two rectifying elements. The output terminals of the two generator coils are connected to the two input terminals of a differential amplifying circuit and the output of the differential amplifying circuit is given as input signal of the ignition circuit.