Abstract: In a method for creating a spark across a spark gap, in particular for igniting a flammable liquid to measure its flash point, by means of a spark generator which comprises an ignition transformer, wherein the spark generator, on the primary side of the ignition transformer, comprises at least one DC voltage source and, on the secondary side of the ignition transformer, comprises two electrodes delimiting the spark gap to be formed, wherein voltage pulses from the DC voltage source are applied to the ignition transformer on the primary side thereof, which voltage pulses generate ignition voltage pulses on the secondary side, the ignition transformer is operated in a first phase according to the flyback converter principle and in a subsequent, second phase according to the forward converter principle.

Abstract: An apparatus, as an electromagnetic wave back introduction blocking module connected between an ignition (IG) system and a converter, includes a front capacitor module which includes a first coil part including one or more coils having one side connected to the IG system in series and a first capacitor part connected between the other side of the first coil part and a ground, a central coil module which includes a second coil part including one or more coils having one side connected to the other side of the first coil part and a second capacitor part connected between the other side of the second coil part and the ground, and a rear capacitor module which includes a third capacitor part having one side connected to the other side of the second coil part. The rear capacitor module is connected to the converter.

Abstract: An apparatus for igniting a fuel mixture provides an ignition system for generating a high-voltage ignition voltage, a circuit device comprising a circuit for superimposing a high-frequency signal on to the high-voltage ignition voltage, a spark plug in an engine block, and a transmission element having a high-voltage conductor which is guided in an insulation element. The high-voltage conductor is used for transmitting the ignition voltage, onto which the high-frequency signal has been superimposed, to the spark plug. Further provided is an electrically conducting shielding element which surrounds the high-voltage conductor in an electromagnetically shielding manner at least along one portion of the longitudinal axis of the high-voltage conductor. The shielding element is connected in an electrically conducting manner to a ground potential of the circuit device and establishes a connection between the ground potential of the circuit device and a ground electrode of the spark plug.

Abstract: In at least some implementations, a method of operating an ignition system for a combustion engine includes charging an energy storage device during at least a portion of the time when the engine is operating, permitting the level of energy stored on the charge storage device to decrease over time after the engine ceases to operate, determining the energy level on the energy storage device when the engine is restarted after having ceased operating, and setting at least one engine operational parameter as a function of the determined energy level. In at least some implementations, the at least one engine operational parameter may include one or more of: richness of a fuel and air mixture to be delivered to the engine, ignition timing, desired engine idle speed.

Abstract: The present invention features an ignition coil of an engine, in which a small condenser is directly installed to an LV pin of the ignition coil, thus effectively removing noise, and dissipating heat from the ignition coil to an outside, in addition to preventing the inflow of water.

Abstract: The present invention is an installation of an emergency starting switching device and/or direct current boosted boost circuit device. When the power of the starting battery is insufficient, the electric energy of the auxiliary battery is used to drive the starting motor in order to start the engine by operating the emergency starting switching device. And when the engine is started, the voltage of the ignition device or the fuel injection device is stepped up to strengthen its starting capability by means of a voltage boost by the direct current boosted boost circuit device.

Abstract: There is obtained an ignition apparatus, for an internal combustion engine, that can make a predetermined output current flow in a stable manner so that the combustion state of the internal combustion engine can always be maintained in a good condition, even in the case where the voltage of the power source connected with the energy storing coil fluctuates.

Abstract: An ignition coil apparatus for an internal combustion engine with a cylinder having first and second spark plugs can reliably detect an ionic current without discharging a bias voltage even at the start of supplying a primary current. The apparatus includes a coil member with primary and secondary coils. The secondary coil has first and second ends connected to the spark plugs through high voltage output terminals, respectively. A first diode has its anode connected to a capacitor, and its cathode connected between the first end of the secondary coil, at which a high positive voltage is generated upon interruption of the primary current, and a high voltage output terminal at a secondary coil first end side. A second diode has its anode connected to the secondary coil first end, and its cathode connected to a junction between the first diode and the high voltage output terminal.

Abstract: In a multiple discharge ignition control apparatus, a battery, an energy storage coil and a first IGBT are connected in series. Further, the energy storage coil, a diode, a primary coil and a second IGBT are connected in series. The energy storage coil is connected with a capacitor through the diode, and a secondary coil is connected with a spark plug and a resistor for current detection. An ignition control circuit switches the IGBTs between ON and OFF each time the secondary current detected by the resistor reaches a positive or negative discharge holding current in multiple discharge operation. A booster circuit is provided in addition to the energy storage coil and its output is feedback-controlled.

Abstract: A circuit for controlling an ignition coil is provided. The circuit includes a first transistor, second transistor, and a capacitor. The first transistor is connected in electrical series between the ignition coil and a voltage reference. The capacitor is connected between the ignition coil and a control input of the first transistor. The second transistor is configured to selectively connect the capacitor to the voltage reference.

Abstract: A system 10 for increasing electrical spark current to the spark plugs of an electronic ignition system for internal combustion engines includes a capacitor 12 parallel with a switch 14; a primary winding 16; a secondary winding 18 in series with a spark plug 20, the capacitor 12 and switch 14 being in series with the primary winding 16; and a battery 22 having a positive terminal connected to the primary winding 16, and a negative terminal connected to the capacitor 12, switch 14 and spark plug 20. The components cooperating to direct positive and negative electrical currents through the primary winding 16 whereby a peak to peak primary winding current occurs that induces a corresponding secondary winding current through said secondary winding 18.

Abstract: An ignition system and a method for operating an ignition system provides reliable suppression of a closing spark ignition at relatively small expense and to achieve a reliable ignition by the ignition spark. To assure a high energy supply to the spark plug, an ignition system is created having a functional device for receiving a drive signal and for producing a pulse signal, an ignition transistor for receiving the pulse signal, an ignition coil, whose primary winding connections are connected in a primary current circuit that is fed by a vehicle power supply source and that can be switched using the ignition transistor, and whose secondary winding connections are connected in a secondary current circuit for receiving a spark plug.

Abstract: An ignition device for an internal combustion engine comprising: an ignition coil comprising a primary winding and a secondary winding, the ignition coil generating an igniting high voltage in the secondary winding by turning off a primary current flowing in the primary winding; an ignition switching unit; a spark plug connected to an igniting high voltage generation end of the secondary winding; a reverse current prevention unit series-connected on a current-conduction path of the discharge current connecting the secondary winding to the spark plug; a voltage application unit connected to an other end of the secondary winding opposite to the igniting high voltage generation end; an ionic current detection unit; and an ionic current detection switching unit series-connected on a current-conduction path of the ionic current-detecting voltage connecting the voltage application unit to the other end.

Abstract: An ignition device for an internal combustion engine having multiple cylinders and direct gasoline injection is described, so that the secondary current conduction time of the ignition coil can be prolonged controllably without increasing the primary current. At least one ignition coil is provided for each cylinder of the internal combustion engine. The primary side of the ignition coil is switched over an ignition switch which is triggered by a microprocessor. A spark plug is connected to the secondary side of the ignition coil. An external voltage can be applied to the ignition coil to prolong the secondary current conduction time, thus supplying the power required for the prolonged secondary current.

Abstract: A circuit for supplying an oscillation suppress current is provided between a collector terminal and gate electrode of a main IGBT. The current supply circuit comprises a resistor and a diode which are connected in series. A bypass MOSFET is connected between the series connection and the emitter terminal. No semiconductor element having different temperature characteristics is provided in the current supply circuit.

Abstract: An ignition coil assembly includes a high voltage (HV) diode at both ends of the secondary winding. The diodes prevent a spark-on-make condition. The diode implementation has particular benefits when used in a 42 volt automotive electrical system.

Abstract: The invention relates to an inductive ignition device for an internal combustion engine, having an ignition coil (ZS) with a primary coil (L1) and a secondary coil (L2), wherein a diode (D) is provided on the side of the secondary coil (L2), having a spark plug (ZK) with at least one electrode, and having a measuring device for detecting an ionic current (14). A shunt device (16) is provided in order to decrease a residual charge that is present between the diode (D) and an electrode of the spark plug (ZK). The shunt device (16) preferably contains a high-impedance resistance (R) connected in parallel with the diode (D). This permits a reliable detection of combustion misses in the ionic current signal.

Abstract: An ignition coil assembly includes a high voltage (HV) diode at both ends of the secondary winding. The diodes prevent a spark-on-make condition. The diode implementation has particular benefits when used in a 42 volt automotive electrical system.

Abstract: An ignition system and a method for operating an ignition system provides reliable suppression of a closing spark ignition at relatively small expense and to achieve a reliable ignition by the ignition spark. To assure a high energy supply to the spark plug, an ignition system is created having a functional device for receiving a drive signal and for producing a pulse signal, an ignition transistor for receiving the pulse signal, an ignition coil, whose primary winding connections are connected in a primary current circuit that is fed by a vehicle power supply source and that can be switched using the ignition transistor, and whose secondary winding connections are connected in a secondary current circuit for receiving a spark plug.

Abstract: An ignition device for an internal combustion engine comprising: an ignition coil comprising a primary winding and a secondary winding, the ignition coil generating an igniting high voltage in the secondary winding by turning off a primary current flowing in the primary winding; an ignition switching unit; a spark plug connected to an igniting high voltage generation end of the secondary winding; a reverse current prevention unit series-connected on a current-conduction path of the discharge current connecting the secondary winding to the spark plug; a voltage application unit connected to an other end of the secondary winding opposite to the igniting high voltage generation end; an ionic current detection unit; and an ionic current detection switching unit series-connected on a current-conduction path of the ionic current-detecting voltage connecting the voltage application unit to the other end.

Abstract: In an ignition apparatus for internal combustion engine, since a current caused to flow by an induced voltage generated at both ends of a secondary winding L2 when starting conduction to a primary winding L1 is checked from the conduction by diode for prevention of a reverse current 31, a spark discharge is not generated between the electrodes 13a-13b of the spark plug 13 when starting the conduction to a primary winding L1. After ending the spark discharge, the ionized current is generated between the electrodes of the spark plug by impressing the induced voltage (the ionized current generating voltage) created at both ends of the air-fuel mixture by a residual energy of the ignition coil 15.

Abstract: In an ignition apparatus for internal combustion engine, since a current caused to flow by an induced voltage generated at both ends of a secondary winding L2 when starting conduction to a primary winding L1 is checked from the conduction by diode for prevention of a reverse current 31, a spark discharge is not generated between the electrodes 13a-13b of the spark plug 13 when starting the conduction to a primary winding L1. After ending the spark discharge, the ionized current is generated between the electrodes of the spark plug by impressing the induced voltage (the ionized current generating voltage) created at both ends of the air-fuel mixture by a residual energy of the ignition coil 15.

Abstract: The primary winding of an ignition coil is connected in series with an ignition switch that can be switched by a control circuit. A circuit including a capacitor, a resistor, and a diode is configured between the control terminal and the collector of the ignition switch. When the primary current is switched on, the capacitor discharge brings about a voltage reduction at the base of the ignition switch resulting in slowing down the trailing voltage edge at the collector of the ignition switch.

Abstract: An inductive ignition device for spark plugs of an internal combustion engine is having at least one activation circuit for at least one ignition coil and having at least one spark plug. A high-voltage switch associated with the at least one spark plug is brought by a first activation signal of the activation circuit into a conductive, switched-on state. In the switched-on state, the high-voltage switch has passing through it the spark current (I.sub.2) of the at least one spark plug (3; 3a to 3n), and which is designed so that without further activation it remains in the conductive state until the spark current falls below a certain value (holding current).

Abstract: An ignition system includes an ignition coil which provides ignition voltage of one polarity, an igniter which supplies the primary current to the ignition coil at regular timings and a zener diode connected in series with the primary coil of the ignition coil. The zener diode shares a constant voltage drop of the opposite polarity at the secondary coil of the ignition coil, thereby reducing troublesome voltage induced in said secondary coil other than at regular ignition timings. On the other hand, the zener diode does not share the voltage drop of the ignition voltage at the regular timings, and thus no energy loss is incurred.

Abstract: To provide an ignition device advantageous in cost and space by using an inexpensive small-sized Zener diode having a Zener voltage lower than an induced voltage generated at a primary current supply timing, so as to prevent sparking of a spark plug due to the induced voltage. An ignition device for an internal combustion engine, includes a Zener diode provided on the secondary lower-voltage side of an ignition coil. The Zener diode comes into conduction at a voltage lower than an induced voltage generated at a primary current supply timing.

Abstract: The invention describes a novel circuit to be used in spark-ignition combustion engines. An ignition circuit according to the invention extends the voltage decay time following the initial generation of a spark across the spark plug gap. In addition, it reduces the oscillation of the voltage following any secondary negative spike. Use of the circuit increases combustion efficiency and reduces wear and tear on the spark plugs. This purpose is achieved by including a diode and a capacitor in the spark circuit; alternately, the diode may act as a capacitor when reverse biased.

Abstract: An ignition system includes an ignition coil which provides ignition voltage of one polarity, an igniter which supplies the primary current to the ignition coil at regular timings and a zener diode connected in series with the primary coil of the ignition coil. The zener diode shares a constant voltage drop of the opposite polarity at the secondary coil of the ignition coil, thereby reducing troublesome voltage induced in the secondary coil other than at regular ignition timings. On the other hand, the zener diode does not share the voltage drop of the ignition voltage at the regular timings, and thus no energy loss is incurred.

Abstract: An ignition device for internal combustion engines with stationary high-voltage distribution, having at least one ignition coil (11), wherein a controllable switch (12) is disposed in series with the primary winding (10) and is triggerable by a control unit (13), wherein at least one high-voltage break-over diode (HKD), which comprises a plurality of break-over diode chips, is disposed in each secondary-side ignition branch between the high-voltage-side end of the secondary winding (14) and a spark plug (ZK1, ZK2, . . . , ZKn). A switch triggered by the control unit during the ignition coil charging operation makes a conditioning flow possible through the high-voltage break-over diode (HKD), which current in the high-voltage break-over diode floods the blocking region with charge carriers (38) (FIG. 1).

Abstract: In one embodiment of the present invention, an ignition coil assembly includes a primary coil and a secondary coil. A primary connector assembly of the ignition coil assembly includes a conductor which is adapted to electrically connect one terminal of the primary coil with one terminal of the secondary coil. The conductor includes indentations which delimit a portion of the conductor and facilitate the removal of that portion of the conductor. The conductor further includes provisions for electrically connecting an electrical component such as diode in place of the removed portion of the conductor. The present invention thus facilitates inclusion of an electrical component such as a diode in applications which will benefit from the inclusion of the electrical component in place of the conductor.

Abstract: A spark ignition system and spark plug for utilization in an internal combustion engine combusting an ultra lean fuel/air mixture has capacitors and rectifiers built within the spark plug and the system is constructed to be compact and capable of delivering a controlled spark that has the physical properties of providing a very fast, high power pulse or train of pulses greater than conventional spark plugs.

Abstract: An ignition system for internal combustion engines, has a plurality of spark plugs, an ignition coil provided for the spark plugs and having a secondary circuit, at least one trigger diode cascade formed as a high voltage semiconductor switch and connected in the secondary circuit of the ignition coil prior to each of the spark plugs so as to change suddenly from a blocking state to a conducting state at a preselected voltage for generating ignition sparks, and a capacitor connected parallel to the secondary winding of the ignition coil between the ignition coil and the trigger diode cascade.

Abstract: An internal-combustion-engine ignition device in which such components as the ion-current-detection unit are provided integrally with other ignition-device components to realize a simplified structure, thereby helping to attain a reduction in cost and an improvement in terms of layout and reliability, the internal-combustion-engine ignition device including: a distributor cap having a central electrode connected to an ignition coil, a plurality of peripheral electrodes respectively connected to the ignition plugs of cylinders and adapted to be selectively connected to the central electrode, and diodes each connected at one end to the peripheral electrodes and at the other end to the central electrode, the distributor cap having openings lodging the diodes for detecting an ion current generated upon combustion of air-fuel mixture inside the cylinders, caused by ignition of the ignition plugs.

Abstract: A misfire detector for use in an internal combustion engine has an ignition coil including a primary coil and a secondary coil. An interrupter circuit is provided for on-off actuation of primary current flowing through a primary circuit of the ignition coil. A distributor has a series gap provided in a secondary circuit of the ignition coil, and a spark plug is adapted to be energized from the ignition coil through the series gap of the distributor. A voltage charging circuit works to electrically charge a stray capacity inherent in the spark plug immediately after an end of a spark action of the spark plug. A spark plug voltage detector circuit distinguishes the voltage waveform of more than a predetermined reference voltage level so as to deform the voltage waveform into output signals. On the basis of the width of the output signals, a distinction circuit determines whether or not the spark action ignites an air-fuel mixture in a cylinder of the internal combustion engine.

Abstract: In a misfire detector for use in an internal combustion engine having an ignition coil, an electrical interrupter circuit interrupts a primary current flowing through a primary circuit of the ignition coil by which a spark plug is energized. A voltage divider circuit detects a divided voltage of a spark plug voltage applied across the spark plug. A spark plug voltage detector circuit is provided to detect an attenuation characteristic of a spark plug voltage waveform presented subsequent to a time period predetermined either during a spark action of the spark plug or after an end of the spark action of the spark plug. A peak hold circuit is provided to hold a peak voltage of the spark plug voltage waveform presented after the end of the spark action of the spark plug, so that a distinction circuit determines a misfire on the basis of a peak voltage level or the attenuation characteristics of the spark plug voltage waveform.

Abstract: The ignition system for an internal combustion engine includes an ignition coil having a primary coil and a secondary coil; a plurality of semiconductor switching elements connected with the secondary coil which change abruptly from a blocking state to a conducting state at a predetermined breakdown voltage corresponding to an ignition voltage, each of the semiconductor switching elements including at least one breakdown diode; an ignition line connected electrically to a higher voltage end of the secondary coil and another ignition line connected electrically to a lower voltage end of the secondary coil, each of the ignition lines being connected via one of the semiconductor switching elements to a spark plug and being of different length, wherein the semiconductor switching element in the one line has a different breakdown voltage than the semiconductor switching element in the other line.

Abstract: An ignition apparatus for internal combustion engines of which configuration is simplified to reduce production cost and improve reliability of the apparatus. The present invention with the above object can be completed in three main embodiments. The ignition apparatus according to one embodiment of the present invention has a distributor cap. The distributor cap comprises an ignition coil; a central electrode connected to the ignition coil; a plurality of side electrodes each connected to an ignition plug of each cylinder of the engine and selectively connected to the central electrode; a plurality of diodes each connected to the plurality of side electrodes each; a terminal connected to the diodes for outputting ion detecting signals; and a resin portion for holding the central electrode, the plurality of side electrodes, the plurality of diodes, and the terminal.

Abstract: The present invention discloses a multiple spark transistor ignition circuit which is able to provide negligible retardation of ignition time, and/or prevent ignition with reverse rotation and/or provide an additional advanced spark and/or govern maximum engine speed and/or progressively advance the moment of ignition with increasing engine speed. The basic circuit comprises an ignition circuit of the type disclosed in U.S. Pat. No. 4,163,437 (Notaras) with a diode interposed between the primary winding and the remainder of the circuit. Circuits having a single primary winding and dual remainders or dual primary windings and single remainders are also disclosed. A governor circuit having a control transistor, a further potential divider and a control capacitor, is also disclosed.

Abstract: To suppress negative half-waves derived from a magneto armature and not used for ignition without use of external damping networks, the semiconductor switch controlling current flow, and abrupt turn-off to initiate an ignition event, is formed as a monolithic semiconductor element, and the inherent inverse diode of the monolithic element is utilized to pass the reverse voltage half-waves. To prevent damage to the inherent diodes due to over-voltage or current overloading, a damping resistance element is connected in series with the main current carrying path of the monolithic circuit elements, preferably a Darlington transistor, which, preferably, is a semiconductor resistor having a preferred current passage characteristic in the same direction as the current flow through the Darlington transistor, for example a Zener diode, a resistor, or a series of diodes polarized like the inverse diode, bridged by a diode conducting in the same direction as the Darlington transistor, or the like.

Abstract: A high-voltage switch is suggested, particularly for ignition systems of internal combustion engines, which is characterized by a voltage-controlled electronic high-voltage switching unit which passes suddenly from the blocking state into the conducting state at a preselectable and predetermined voltage. The switching unit uses a state-changing or breakdown diode cascade (8) which switches through the voltage at the secondary winding (5) of an ignition coil (7) only after reaching the ignition voltage at the spark plug (1) of an internal combustion engine.

Abstract: An igniter for an internal combustion engine has a plurality of drive circuits for generating an ignition voltage in the secondary winding of an ignition coil. A high-voltage diode is connected in series between the secondary winding of the ignition coil and a spark plug. The diode prevents destructive interference between the ignition voltages generated in the secondary winding for successive firings of the spark plug.

Abstract: To reduce the size of a high-voltage semiconductor optically responsive switch, for example suitable to control the flow of ignition energy from an ignition coil (4) to a spark plug (ZK), a stack of disk or plate-shaped semiconductor chips (9) is formed with the major surfaces of the chips placed against each other and light responsive regions of the chips at the outer surface thereof to form an array of chips with a control surface (14). The light responsive regions (13) are large enough so that, at any position of the respective chips in the array, the can receive sufficient switching energy from a point source, such as a light emitting diode (17) (LED). Thus, a single LED can control all the semiconductor switching elements.

Abstract: The apparatus includes an ignition instruction signal generating unit for repeatedly generating a first ignition instruction signal instructing an AC discharging duration and a second ignition instruction signal instructing the current flow time of a first primary coil at each ignition timing; and an ignition control circuit unit for causing the first and second switching elements to perform a push-pull operation for a predetermined period of time upon reception of a given ignition instruction signal.

Abstract: In an ignition system for an internal combustion engine which is operable in synchronism with rotation of the engine to switch on and off a primary current in an ignition coil and applies to a spark plug a high voltage induced in the ignition coil secondary winding upon the off switching, a Zener diode is connected to the low-voltage side of the ignition coil secondary winding in order to prevent a secondary voltage induced upon the on switching of the primary current from being applied to the spark plug.

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 system for an internal combustion engine has an ignition coil coupled to a first and second spark plug provided for each cylinder. A first diode is coupled in series between the first spark plug and the ignition coil. A second diode is coupled in series between the second spark plug and the ignition coil. A first capacitor is coupled in parallel with the first spark plug. A second capacitor is coupled in parallel with the second spark plug.

Abstract: An ignition device for an internal combustion engine, in which a current-supply terminal other than two end terminals of the second winding of the ignition coil is provided in the second winding or at the tertiary winding of the ignition coil: a diode is connected to the current-supplying terminal; a resistor is connected to one end of the secondary winding; the diode and the resistor are connected at one end in common; the spark gap of the combustion engine is connected between the common connection junction and the other end of the secondary winding; and the polarity of the diode is determined to be forward with respect to a discharge current flowing through the spark gap. An auxiliary power source may be provided in a network including the spark gap and the diode for increasing a discharge current of the spark gap.

Abstract: A diesel engine is started by plural ignition plugs, each installed in a swirl chamber of a corresponding cylinder. Each ignition plug includes (a) an elongated center electrode, (b) a fuel-absorbent electrical insulator that encapsulates the center electrode so as to allow only one end of the center electrode to protrude, and (c) a plurality of elongated grounding electrodes arranged symmetrically around said insulating member to define a discharge path in conjunction with the protruding end of the center electrode. The discharge path includes part of the surface of the insulating member and an air gap between free ends of the grounding electrodes and opposing surfaces of the insulating member.

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: An ignition system of the type incorporating, instead of the usual distributor, high-voltage rectifier diodes connected between the secondary winding of an ignition coil and respective spark plugs. In response to voltages developed in the secondary winding in its opposite directions the diodes function to cause discharges at the spark plugs in the firing order of the engine. Each diode is composed of a multiplicity of laminated silicon rectifier diode chips each having a reverse breakdown voltage in the range of 400-850 volts. The reverse breakdown voltage of each diode is 1.1 to 1.8 times the maximum discharge voltage of the spark plugs. Thus constructed, the diodes can well withstand overvoltages that may develop in the secondary circuit of the ignition system.