US3677253A - Capacitor discharge type ignition system for internal combustion engines - Google Patents

Capacitor discharge type ignition system for internal combustion engines Download PDF

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Publication number
US3677253A
US3677253A US65586A US3677253DA US3677253A US 3677253 A US3677253 A US 3677253A US 65586 A US65586 A US 65586A US 3677253D A US3677253D A US 3677253DA US 3677253 A US3677253 A US 3677253A
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Prior art keywords
capacitor
primary winding
reactor
converter
ignition system
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US65586A
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Inventor
Kazuo Oishi
Tokuhiro Kurebayashi
Noriyoshi Ando
Noboru Yamamoto
Hiroshi Yoshida
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Denso Corp
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NipponDenso Co Ltd
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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02P—IGNITION, OTHER THAN COMPRESSION IGNITION, FOR INTERNAL-COMBUSTION ENGINES; TESTING OF IGNITION TIMING IN COMPRESSION-IGNITION ENGINES
    • F02P3/00—Other installations
    • F02P3/06—Other installations having capacitive energy storage
    • F02P3/08—Layout of circuits
    • F02P3/0876—Layout of circuits the storage capacitor being charged by means of an energy converter (DC-DC converter) or of an intermediate storage inductance
    • F02P3/0884—Closing the discharge circuit of the storage capacitor with semiconductor devices

Definitions

  • CAPACITOR DISCHARGE TYPE IGNITION SYSTEM FOR INTERNAL COMBUSTION ENGINES [72] Inventors: Kazuo Oishi; Tokuhiro Kureblyashl;
  • ABSTRACT in a capacitor discharge type ignition system for internal combustion engines, which generates ignition sparks between electrodes of a spark plug by rapidly discharging a charged capacitor through the primary circuit of an ignition coil, the improvement residing in that the said primary circuit is provided with additional reactance elements so that said reactance elements constitute an oscillation circuit including said primary circuit, to thereby extend the duration of the ignition spark and ensure relative and effective operation of the ignition system.
  • This invention relates to a capacitor discharge type ignition systems for internal combustion engines to control the electric spark caused to bridge the spark plug electrodes for igniting and firing the mixture of gasoline as the fuel and air.
  • FIG. I is a circuit diagram, partly in the block form, showing the conventional capacitor discharge type ignition system
  • FIG. 2 is a circuit diagram of an embodiment of the capacitor discharge type ignition system according to the invention.
  • FIG. 3 is a circuit diagram of a second embodiment of the capacitor discharge type ignition system according to the invention.
  • FIG. 4 is a circuit diagram showing a modification of the gate circuit in the capacitor discharge type ignition system according to the invention.
  • FIG. 5 is a circuit diagram showing a modification of the DC-to-DC converter in the capacitor discharge type ignition system according to the invention.
  • FIG. 6 is a circuit diagram, partly in block form, showing a third embodiment of the capacitor discharge type ignition system according to the invention.
  • FIG. 7 is a graph showing the waveform of the current through the ignition coil in the embodiment of FIG. 6;
  • FIG. 8 is a circuit diagram, partly in block form, showing a fourth embodiment of the capacitor discharge type ignition system according to the invention.
  • FIG. 9 is a graph showing the waveform of the current through the ignition coil in the embodiment of FIG. 8.
  • FIGS. ID to 13 are circuit diagrams, partly in block form, showing further embodiments of the capacitor discharge type ignition system according to the invention.
  • the prior-art ignition system of the type, to which the invention pertains comprises a DC-to-DC converter to step up a low DC source voltage to a high DC voltage and a capacitor charged and discharged in accordance with the output voltage of the DC-to-DC converter.
  • the discharging circuit of the capacitor is constituted by connecting the primary winding of the ignition coil in series with a switching element such as a silicon controlled rectifier element. Upon triggering of the switching element the charge stored on the capacitor is discharged through the primary winding of the ignition coil to induce a high surge voltage across the secondary winding of the ignition coil.
  • FIG. I shows a typical example of the prior-art ignition system of the type just described.
  • the figure comprises a battery source I, a DC-to-DC converter 2, a capacitor 3 charged by the output voltage of the DC-to-DC converter 2, an ignition coil 4 having a primary winding 4a, a secondary winding 4b and an iron core 4c, a silicon controlled rectifying element 5 (hereinafter referred to as SCR), a gate circuit 6 delivering the gate signals to the gate of the SCR 5 in synchronism with the rotation of a rotary shaft related in phase to the rotation of the engine crankshafi not shown, and a spark plug 7 provided in the engine.
  • SCR silicon controlled rectifying element 5
  • the SCR 5 is 05" in the absence of the gate signal at its gate, triggered when it receives the gate signal from the gate circuit 6 and cut ofiafier the gate signal disappears.
  • the SCR is OK, the capacitor 3 is charged by the output voltage of the DC-to-DC converter 2.
  • the terminal voltage built up acros the capacitor 3 is substantially equal to the output voltage of the DC-toDC converter 2.
  • the gate circuit 6 generates a gate signal to trigger the SCR 5
  • the charge accumulated on the capacitor 3 is rapidly discharged through the primary winding 40 of the ignition coil 4 and the SCR 5, thus inducing a high voltage across the secondary winding 4b of the ignition coil 4 to cause a spark between the electrodes of the spark plug 7.
  • the capacitor 3 is reversely charged, that is the polarity of the voltage built up across the capacitor 3 is reversed, owing to the inductance of the primary winding 4a.
  • the current in the primary winding 40 thus does not cease immediately after the capacitor 3 is completely discharged but reversely charges the capacitor 3, as the capacitor 3 and the prirrmry winding 4a constitute a series-resonant circuit.
  • the current continues to flow in the prinmry winding 4a in the same direction, until the terminal voltage developed across the capacitor 3 in the polarity opposite to that when the capacitor 3 is being discharged reaches a maximum value, at which time the SCR 5, reversely biased by the terminal voltage of the reversed polarity across the capacitor 3, and undergoes transition into the non-conduction state.
  • the gate signal from the gate circuit 6 has already disappeared.
  • the spark bridging the electrodes of the spark plug 7 disappears.
  • the reversely charged capacitor 3 is thereafter discharged through the internal circuit of the DC-to-DC converter 2 and then re-charged from the DC-to-DC converter 2.
  • the above sequence of operation is repeated to produce sparks between the electrodes of the spark plug 7 in accordance with the spark timing.
  • the impedance of the primary winding 4a of the spark coil 4 is made extremely low to cause an extremely high current in the primary winding 40 when the capacitor 3 is discharged upon triggering of the SCR 5, so that a very strong high-voltage spark may be produced across the gap between the electrodes of the spark plug 7.
  • the duration of the spark across the electrodes of the spark plug 7 is extremely short. This sometimes results in ignition failure, that is, the spark fails to continue sufiiciently long to fire the mixture of fuel and air admitted into the engine cylinder.
  • the ignition current flowing between the electrodes of the spark plug is so decreased as not to ignite the mixture of fuel and air in the engine, particularly when the spark plug electrodes are contaminated with carbon. Also, since most of the energy stored in the ignition coil 4 as the capacitor 3 is discharged is consumed in producing the spark, only a fraction of the energy transferred to the ignition coil 4 is returned to the capacitor 3, so that the reverse terminal voltage across the capacitor 3 reversely biasing the SCR 5 is sometimes insufficient to cut ofi' the SCR 5.
  • the capacitor 3 cannot be re-charged in the next recharging cycle, and only a constant current determined by the DC-to-DC converter 2 and the charging and discharging circuit flow through the primary winding 4a of the ignition coil 4.
  • the gate circuit 6 delivers a gate signal to the SCR 5 in the condition state, a surge current will not be caused in the primary winding 4a of the ignition coil 4, since the capacitor 3 has not been charged but the constant current determined by the DC-to-DC converter 2 and the charging and discharging circuit has been flowing through the primary winding. Consequently, no high voltage is induced across the secondary winding 4b of the ignition coil 4 and no spark is produced across the electrodes of the spark plug 7, which is a serious disadvantage.
  • a principal object of the invention is to overcome the above disadvantages of the prior-art ignition system, that is, to sumciently extend the duration of the spark and ensure the transition of the switching element into the nonconduction state after the extinction of the initial spark.
  • a capacitor discharge type ignition system comprising a capacitor charged by the output voltage of a DC-to-DC converter, and a discharging circuit, through which the capacitor is discharged, and which includes the primary winding of the spark coil and a switching element connected in series with the primary winding and having a gate, wherein the charging circuit further includes at least one additional capacitor and at least one additional inductor coil to constitute an electric pulsation circuit together with the primary winding of the ignition coil, thereby extending the duration of the discharge current flowing through the primary winding of the ignition coil by a predetermined time interval.
  • numeral 11 designates a battery source and numeral 12 a blocking oscillator type DC-to-DC converter to step up the low DC voltage of the battery source 11 into a high DC voltage.
  • the DC-to-DC converter 12 comprises a bias resistor 12a, a transistor 12b, a feedback resistor 12c, a feedback capacitor 12d, a transfomier 12e, and a capacitor 12f to mitigate the spike voltage induced across the secondary of the transformer 12e.
  • Numeral 13 designates a first capacitor charged with the output voltage of the DC-to-DC converter 12, numeral 14 a diode, numeral 15 a second capacitor, and numeral 16 a saturable reactor.
  • Numeral 17 designates an ignition coil including a primary winding 17a, a secondary winding having several ten times the number of turns of the primary and an iron core 17c.
  • Numeral 18 designates a spark plug provided in an engine cylinder not shown for igniting the airfuel mixture admitted into the cylinder.
  • Numeral l9 designates an SCR, which is triggered to cause discharging of the electricity stored in the first capacitor 13 so as to provide current through the second capacitor 15 and the primary winding 17a of the ignition coil 17.
  • Numeral designates a gate circuit to deliver a gate signal (trigger signal) to the gate of the SCR 19. It comprises a switch 200 on-olf operated by a shaft means (not shown) rotated in association with the engine crankshaft, a discharging resistor 20b, a capacitor 200, a diode 20d and a current-regulating resistor 20e.
  • the discharging current from the first capacitor 13 partially flows through the other discharging path consisting of the diode 14 and the saturable reactor 16, a substantial part of the discharging current from the first capacitor 13 passes through the primary winding 17a of the ignition coil 17, because the reactance offered by the saturable reactor 16 is made large compared to the reactance offered by the primary winding 17a of the ignition coil 17.
  • the large current flowing through the primary winding 17a of the ignition coil 17 thus induces a high surge voltage acres the secondary winding 17!: to produce a strong high-voltage spark bridging the electrodes of the spark plug 18.
  • the second capacitor 15 begins to store charge, and a great quantity of charge is transferred from the first capacitor 13 to the second capacitor 15 and stored therein.
  • the gate signal current to the SCR 19 is present only for a short time determined by the capacitor 20: and the resistor 20c of the gate circuit 20, and is already absent by the time the second capacitor 15 is charged to a maximum, at which time the current through the primary winding 17a of the ignition coil 17 is reduced to zero.
  • the SCR 19 is cut otf when the reverse bias voltage thereacross reaches a predetermined value, and is thereafter maintained 06" until a next gate signal appears at its gate.
  • the charge built up in the second capacitor 15 is thus discharged through the diode 14, saturable reactor 16 and primary winding 17a of the ignition coil 17. The duration of this discharging is comparatively longer by virtue of a high reactance ofiered by the saturable reactor 16.
  • the direction of the discharging current from the second capacitor 15 through the primary winding 17a of the ignition coil 17 is opposite to the direction of the discharging current caused from the first capacitor through the primary winding 17a of the ignition coil 17 upon triggering of the SCR 19.
  • the spark caused across the electrodes of the spark plug 18 temporarily ceases at the time the direction of current through the primary winding 17a of the ignition coil 17 is inverted, but it is readily resumed with a fairly low voltage after the inversion of the direction of current through the primary winding by virtue of the fact that ions produced by the previous sparking remain around the electrodes of the spark plug 18.
  • the duration of the resumed spark is comparatively longer because of a relatively long period, during which the discharging current from the second capacitor 15 flows through the primary winding 17a of the ignition coil 17, thus insuring stable ignition of the air-fuel mixture.
  • the first capacitor 13 begins to be re-charged by the output voltage of the DC-to'DC converter 12 when the SCR 19 is cut off, and the system becomes ready for the impression of a next gate signal on the gate of the SCR 19.
  • the duration of the spark caused by the discharging of the second capacitor 15 may be set to a suitable value by varying the reactance of the saturable reactor 16. This means that the diode 14 may be dispensed with if the period of the pulsating current is made sufficiently short as compared to the ignition cycle.
  • FIG. 3 shows a second embodiment of the ignition system according to the invention.
  • the primary winding of the ignition coil 17 is tapped at (a) for connection to the anode ofthe SCR 19.
  • the duration of the spark caused by the discharging of the second capacitor may be suitably set by varying the reactance of the saturable reactor 16 and that of the auxiliary primary winding portion 17d.
  • the gate control circuit in the preceding embodiments of FIGS. 2 and 3 may be replaced with the one shown in FIG. 4.
  • this gate circuit as a rotary magnet 20f is rotated in association with the engine crankshaft, high surge voltages are induccd across a generator winding 203 to switch a transistor 20h.
  • the switching of the transistor 20h gives rise to squarewave pulses at the collector thereof, which are differentiated by a differentiating circuit including a capacitor 202' and a resistor 20f to produce positive differentiated pulses.
  • the resultant difierentiated pulses are delivered as the gate signal to the gate of the SCR 19.
  • the DC-to-DC converter 12 in the preceding embodiments of FIGS. 2 and 3 may be replaced with the one shown in FIG. 5. As shown in the figure, it may be of the electromagnetic feedback self-sustaining multivibrator type, comprising a pair of transistors 12!: and 121', which are self-oscillated by the alternate positive feedback through a transformer l2j.
  • the spike voltage removal capacitor I2 provided in the preceding embodiments of FIGS. 2 and 3 is unnecessary.
  • the SCR 19 in the above embodiments of FIGS. 2 and 3 may be replaced with other semiconductor switching elements such as transistors or mechanical contact means.
  • FIG. 6 shows a third embodiment of the invention. As is seen from the figure, this embodiment is similar to the embodiment of FIG. 2 except for that a silicon symmetrical switch 22 (hereinafter referred to as SSS) is connected in parallel with the diode 14.
  • SSS silicon symmetrical switch 22
  • the circuit consisting of the second capacitor 15, winding 17a, saturable reactor I6 and diode 14 cannot provide sustained electric oscillation because of the diode 14 connected in series therein. This means that current is caused through the primary winding 17a of the ignition coil 17 only twice in one ignition cycle.
  • the peak terminal voltage across the second capacitor 15 for every half cycle of oscillation in one ignition cycle is successively decreased, and when the peak voltage across the capacitor I5 becomes too low for the SSS to breakdown, the SSS 22 is no longer triggered, so that the electric oscillation in the afore-said circuit ceases.
  • the capacitor 15 always has its terminal connected to the primary winding 17a of the ignition coil 17 positively polarized by virtue of the diode I4.
  • the overall spark duration in one ignition cycle is extended as compared to the first embodiment.
  • the circuit parameters of the discharging circuit, through which the capacitor 13 is discharged are preset to provide an appropriate duration of the attenuating oscillation in this circuit.
  • the sufiicient duration of the arc current between the electrodes of the spark plug in one ignition cycle is about I to 1.5 msec. Extending the duration of the arc current beyond this range by increasing the duration of the attenuating electromagnetic oscillation in the discharging circuit is useless and results in an increased power loss in the discharging circuit.
  • the SCR 19 might be triggered for the next ignition cycle while there is still discharging current flowing from the second capacitor 15 through the diode l4, saturable reactor 16 and winding 17a. If this occurs, all the current from the DC-to-DC converter 12 and from the first capacitor 13 will flow through the route of the diode I4 and saturable reactor [6 into the SCR 19, causing no current through the primary winding 17a of the ignition coil 17 and hence no spark between the electrodes of the spark plug [8, thus resulting in ignition failure and eventually stopping the engine as this undesired situation takes place in the succeeding ignition cycles.
  • This result is prevented by setting the duration of the attenuating electric oscillation in one ignition cycle to be 1 to L5 msec. as mentioned above, because the period of the ignition cycle is usually 2.5 to 3 n'sec.
  • FIG. 7 shows the waveform of the current through the primary winding 17a of the ignition coil 17 in the third embodiment.
  • Current as indicated at (a) first flows through the pri mary winding 17a upon triggering of the SCR I9, and current as indicated at (b), (c), (d), (e) and (f) is subsequently caused to flow through the primary winding 17a by the attenuating electric oscillation in the circuit including the second capacitor 15, primary winding 17a and saturable reactor 16.
  • the current through the primary winding 17a of the ignition coil I7 is not continuous but pulsating or intemiittent involving non-current intervals as indicated at (a), (b'), (c'), (d') and (e').
  • FIG. 8 shows a fourth embodiment of the ignition system according to the invention. This embodiment is similar to the third embodiment of FIG. 6 except for that in this embodiment a third capacitor 23 and a reactor 24 are connected to the output terminal of the DC-to-DC converter 12 and the first capacitor 13 is charged through the reactor 24.
  • the resonant circuit comprising the second capacitor 15, primary winding 17a of the ignition coil 17, saturable reactor 16, diode l4 and SSS 22 is referred to as the first resonant circuit
  • the resonant circuit comprising the third capacitor 23, reactor 24 and first capacitor 13 is referred to as the second resonant circuit.
  • the period of oscillation of the second resonant circuit is determined by the capacitance of the first and third capacitors l3 and 23 and the inductance of the reactor 24.
  • the electric oscillation in the first resonant circuit brings about periodic change of the terminal voltage across the first capacitor 13. As the first and second resonant circuits are connected to each other, they interfere with each other.
  • the waveform of the electric oscillation in the second resonant circuit that is, the current through the primary winding 17a of the ignition coil 17, is quite ditferent from that described in connection with FIG. 7.
  • FIG. 9 shows such waveform of the current through the primary winding 17a of the ignition coil 17.
  • A indicates current caused to pass through the primary winding 17a upon the triggering ofthe SCR I9
  • B, C, D, E, F, G, H, I, .l, K and L indicate the subsequent pulsating current through the primary winding 17a.
  • m is seen, the oscillation is not a purely attenuating oscillation owing to the interfering influence of the second resonant circuit on the oscillation of the first resonant circuit. Similar to FIG.
  • time interval corresponds to the duration of the oscillation in the third embodiment of FIG. 6, and time interval t is the overall duration of the oscillation in the fourth embodiment of FIG. 8.
  • FIG. shows a fifth embodiment of the invention.
  • This embodiment includes a circuit having a breakdown character, which comprises a zener diode 22b and an SCR 22d and replaces the SSS 22 in the embodiment of FIG. 8.
  • the operation of this embodiment is similar to the operation of the embodiment of FIG. 8.
  • the zener diode is triggered to provide a voltage divided between resistors 22a and 22c to the gate of the SCR 221, thus triggering the SCR 224'.
  • the zener diode 22b When the SCR 22d is triggered, the zener diode 22b is short-circuited and the gate voltage disappears, but the SCR 22d continues to carry current until the forward voltage thereacross becomes very low. It will be seen that the zener voltage of the zener diode 22b in this embodiment corresponds to the breakdown voltage of the SSS 22 in the prevb ous embodiment.
  • FIG. II shows a sixth embodiment of the invention.
  • the function of the first and second capacitors I3 and I5 is the same as in the preceding embodiments.
  • This embodiment includes a third capacitor 25, a first saturable reactor 26 and a second saturable reactor 27.
  • the first capacitor I3 is charged to develop a high voltage by the output voltage of the DC-to-DC converter 12.
  • the SCR I9 is otF
  • no current is present in the first and second saturable reactors 26 and 27 and the primary winding 17a of the ignition coil 17. Also, no charge is stored on the second and third capacitors I5 and 25.
  • the gate circuit 20 delivers a gate signal to trigger the SCR 19
  • the charge accumulated on the first capacitor 13 to develop a high voltage is rapidly discharged through the route consisting of the second capacitor 15, winding 17a and SCR I9 and the route consisting of the third capacitor 25, the first saturable reactor 26 and the SCR 19.
  • the second saturable reactor 27 constitutes a third route of discharge of the capacitor I3
  • most of the discharging current from the first capacitor 13 passes through the route respectively consisting of the primary winding 17a of the ignition coil 17 and the saturable reactor 26, because the reactance of the second saturable reactor 27 is greater than the reactance of either the winding I'Ia or the first saturable reactor 26.
  • the current passing through the primary winding 17a induces a high voltage across the secondary winding l7b of the ignition coil I7 to produce a high-tension spark bridging the electrodes of the spark plug 18.
  • the polarity of the first capacitor 13 is subsequently reversed owing to the electric oscillation of the resonant circuit consisting of the third capacitor and first saturable reactor 26, and the second and third capacitors I5 and 25 begin to store charge. By this time, the gate signal to the SCR I9 has already disappeared.
  • the SCR I9 is cut off as it is reversely biased with the reverse voltage developed on the first capacitor 13, and it remains until a subsequent gate signal is impressed on its gate.
  • the charge stored in the second and third capacitors l5 and 26 causes oscillatory currents to flow through the first and second saturable reactors 26 and 27 and the primary winding ":1 of the ignition coil I7 to cause an extended pulsating arc current to pass acros the gap between the electrodes of the spark plug 18 until the oscillatory current is attenuated to a certain level.
  • the first capacitor I3 begins to be charged by the output voltage of the DC-to-DC converter 12. The above sequence of events is repeated as the gate circuit 20 delivers successive gate pulse signals at a predetermined pulse frequency.
  • the duration of the pulsating current, or the duration of the spark may be suitably preset by appropriately varying the capacitance of the second and third capacitors I5 and 2S and the inductance of the first and second saturable reactors to vary the frequency of the electric oscillation.
  • FIG. 12 shows a seventh embodiment of the invention.
  • numeral 28 designates a first reactor
  • numeral 29 a third capacitor charged by the output voltage of the DC-to- DC converter I2 through the first reactor 28, and numeral 30 a second reactor.
  • the function of the first and second capacitors I3 and I5 and other similar components to those in the preceding embodiments is the same as described earlier.
  • the first and third capacitors l3 and 29 are charged to develop a high voltage by the output voltage of the DC-to-DC converter 12.
  • the SCR is "off"
  • no current is present in the second reactor 30 and the primary winding 17a of the ignition coil 17.
  • no charge is stored on the second capacitor 15.
  • the gate circuit 20 delivers a gate signal to trigger the SCR 19
  • the charge accumulated on the first capacitor 13 to develop a high voltage is rapidly discharged through the route of the second capacitor I5, primary winding I7a of the ignition coil 17 and SCR I9.
  • the charge accumulated on the third capacitor 29 is also discharged through the second reactor 30 and SCR 19.
  • the series connection of the first and second reactors 28 and 30 constitute a second route of discharge of the first capacitor I3
  • most of the discharging current from the first capacitor 13 passes through the route of the primary winding 17a of the ignition coil I7, because the resultant reactance of the first and second reactors 28 and 30 is great as compared to the reactance of the winding 17a.
  • the current passing through the primary winding 17a of the ignition coil 17 induces a high voltage across the secondary winding 17b thereof to produce a high-tension spark bridging the electrodes of the spark plug 18.
  • the discharging current from the third capacitor 29 through the second reactor 30 and SCR 19 induces back electromotive force in the second reactor 30, and by virtue of the electric momentum involved the third capacitor 29, having been completely discharged, begins to be reversely charged. Similarly, more charge than the charge accumulated on the first capacitor is transferred to the second capacitor I5. By this time, the gate signal from the gate circuit 20 has already ceased. Thus, the SCR I9 is eventually cut off as it is reversely biased with the negative or reverse voltage developed on the first capacitor 13, and it is held "off” until a subsequent gate signal is impressed on its gate. During the non-conduction of the SCR 19, the charge stored on the second capacitor 15 causes an oscillatory current through the first and second reactors 28 and 30 and the primary winding 17a of the ignition coil 17.
  • the charge stored on the third capacitor 29 gives rise to electric oscillation in the circuit consisting of the first reactor 28, the second capacitor 15, the winding 17a and the second reactor 30. Further electric oscillation takes place in the circuit of the first capacitor I3 and the first reactor 28. These electric oscillations interfere with one another to cause a pulsating current in the primary winding 17a of the ignition coil I7 for an extended period of time, thus causing an extended pulsating arc current through the gap between the electrodes of the spark plug 18.
  • the first and third capacitors 13 and 29 begin to be charged by the output voltage of the DCto-DC converter 12. The above sequence of events is repeated as the unruc gate circuit 20 delivers successive trigger pulses at a predetermined pulse frequency.
  • the duration of the pulsating arc current may be suitably preset by appropriately varying the capacitance of the first, second and third capacitors l3, l and 29 and the inductance of the first and second reactors 28 and 30.
  • FIG. 13 shows an eighth embodiment of the invention.
  • numeral 31 designates a first reactor
  • numeral 32 a second capacitor charged by the output voltage of the DC-to- DC converter 12 through the first reactor
  • numeral 33 a second reactor
  • numeral 34 a third capacitor.
  • the function of the other components is the same as in the preceding embodiments.
  • the discharging current from the first capacitor 13 is superimposed in the primary winding "a of the ignition coil 17 upon the discharging current from the second capacitor 32.
  • the first capacitor 13 is however discharged more slowly as compared to the second capacitor 32 because of the reactance of the first reactor 31.
  • a very high surge voltage is induced across the secondary winding 17b of the ignition coil 17 to very promptly cause a strong spark to pass between the electrodes of the spark plug 18.
  • This strong spark does not momentarily disappear, but is prolonged for a certain interval of time by virtue of the superimposed discharging current from the first capacitor I3, which is caused to pass more gradually through the primary winding [70 of the ignition coil 17.
  • the discharging current from the third capacitor 34 through the second reactor 33 and the SCR l9 induces back electromotive force in the second reactor 33, and the third capacitor 34, having been completely discharged, begins to be reversely charged.
  • the gate signal from the gate circuit 20 has already ceased.
  • the SCR 19 is eventually cut off as it is reversely biased with the negative voltage developed on the third capacitor 34, and it is held ofF until a subsequent gate signal is impressed on its gate.
  • the charge stored on the second capacitor 32 gives rise to the electric oscillation in the first closed circuit consisting of the primary winding 17a of the ignition coil 17, the second reactor 33 and the third capacitor 34.
  • the ignition of the airfuel mixture introduced into the cylinder is ensured.
  • the pulsating current flowing in the primary winding 17a of the ignition coil 17 has been attenuated to a predetermined level, the voltage induced across the secondary winding 17b of the ignition coil 17 becomes insuflicient to cause a spark to bridge the electrodes of the spark plug 18, so that the spark pulsation ceases.
  • the first, second and third capacitors 13, 32 and 34 are charged by the output voltage of the DC-to-DC converter 12. The above sequence of events is repeated as the gate circuit 20 delivers successive trigger pulses at a predetermined pulse frequency.
  • a capacitor discharge type ignition system for internal combustion engine comprising a DC-to-DC converter, a first capacitor charged by the output voltage of said DC-to-DC converter, a discharging circuit, through which said first capacitor is discharged, said discharging circuit comprising a second capacitor, the primary winding of an ignition coil and a switching element connected in series with one another, and a reactor connected acros the said series connection of said primary winding and said second capacitor such that said second capacitor is discharged through said reactor and primary winding in the direction opposite to the direction of discharging of said first capacitor through the primary windmg.
  • a capacitor discharge type ignition system according to claim 1 wherein said reactor is a saturable reactor.
  • a capacitor discharge type ignition system comprising a DC-to-DC converter, a first capacitor charged by the output voltage of said DC-to-DC converter, a first discharging circuit, through which said first capacitor is discharged to cause a spark at a spark plug, said first discharging circuit including a second capacitor, the primary winding of an ignition coil and a switching element, a second discharging circuit, through which said second capacitor is discharged, said second discharging circuit including a diode, a reactor and said primary winding, wherein the discharging circuit for the discharge of said second capacitor after the reversal of the polarity of said second capacitor is formed by said primary winding, said reactor and a switching means having a breakdown character.
  • a capacitor discharge type ignition system according to claim 3, wherein said reactor is a saturable reactor.
  • a capacitor discharge type ignition system comprising a DC-to-DC converter, a first capacitor charged by the output voltage of said DC-to-DC converter and discharged through the primary winding of an ignition coil and a switching element to cause a spark at a spark plug, wherein a second capacitor, said primary winding and said switching element form a first discharging circuit, through which said first capacitor is discharged, a diode, a first reactor and said primary winding form a second discharging circuit, through which said second capacitor is discharged, and said primary winding, said reactor and a switching means having an opposite breakdown character with respect to said diode form a third discharging circuit, through which said second capacitor after the reversal of the polarity thereof is discharged, said ignition system further including a second reactor connected between said first capacitor and the output terminal of said DC-to-DC converter and a third capacitor connected to the connection between the output terminal of said DC-to-DC converter and said second reactor and charged by the output voltage of said DC-to-DC converter.
  • a capacitor discharge type ignition system according to claim 5, wherein said first reactor is a saturable reactor.
  • a capacitor discharge type ignition system comprising a DC-to-DC converter, a first capacitor charged by the output voltage of said DC-to-DC converter, a discharging circuit, through which said first capacitor is discharged, said discharging circuit including a second capacitor, the primary winding of an ignition coil and a switching element connected in series, a first reactor connected in parallel with the series circuit of said second capacitor and said primary winding, and a series circuit including a third capacitor and a second reactor, said last-mentioned series circuit being connected in parallel with the series circuit of said second capacitor and said primary winding.
  • a capacitor discharge type ignition system according to claim 7, wherein said first and second reactors are saturable reactors.
  • a capacitor discharge type ignition system comprising a DC-to-DC converter, a first capacitor charged by the output voltage of said DC-to-DC converter, a discharging circuit, through which said first capacitor is discharged, said discharging circuit including a second capacitor, the primary winding of an ignition coil and a switching element connected in series, a first reactor connected to the output terminal of said DC-to- DC converter, 2 third capacitor charged by the output voltage of said DC-to-DC converter through said first reactor, and a second reactor connected between the connection between said first reactor and said third capacitor and the connection between said primary winding and said switching element.
  • a capacitor discharge type ignition system according to claim 9, wherein said first reactor is saturable reactor.
  • a capacitor discharge type ignition system comprising a DC-to-DC converter, a first capacitor charged by the output voltage of said DC-to-DC converter, a discharging circuit, through which said first capacitor is discharged, said discharging circuit including a first reactor, the primary winding of an ignition coil and a switching element is connected in series, a first series circuit including said first reactor and a second capacitor and connected in parallel with said first capacitor, and a second series circuit including a second reactor and a third capacitor and connected in parallel with said switching element.
  • a capacitor discharge type ignition system comprising:
  • a series circuit including an ignition coil primary winding and a switching device adapted to be turned on and off,
  • a main circuit including said series circuit, through which the charge stored in said capacitor is discharged when said switching device is on for producing current through said primary winding, and
  • an oscillation circuit including a series connection of a second capacitor, an inductive reactance and said primary winding for prolonging the duration of current through said primary winding beyond the turning off of said switching device.
  • An ignition system as in claim 12 including a bidirectional switch in said series connection of said oscillation circuit.
  • An ignition system as in claim 12 including a second inductive reactance serially connected between said converter and first capacitor and a third capacitor connected in parallel across said first capacitor ahead of said second inductive reactance.
  • An ignition system as in claim 15 including a second series circuit connected across said inductive reactance and including a third capacitor and a second inductive reactance.
  • An ignition system as in claim 15 including a second inductive reactance and a third capacitor, said second reactance being connected to the first mentioned reactance in said series connection of said oscillation circuit with said third capacitor being connected to the junction between said reactances.
  • a capacitor discharge type ignition system comprising:
  • an oscillation circuit including said primary winding, said reactor and said second capacitor for prolonging the duration of the discharge current flowing through said primary winding even when the gate of said switching element is closed after the charge of said first capacitor has been transferred to said switching element through said primary winding.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Ignition Installations For Internal Combustion Engines (AREA)
US65586A 1970-01-13 1970-08-20 Capacitor discharge type ignition system for internal combustion engines Expired - Lifetime US3677253A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
JP45003694A JPS4833288B1 (xx) 1970-01-13 1970-01-13

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US65586A Expired - Lifetime US3677253A (en) 1970-01-13 1970-08-20 Capacitor discharge type ignition system for internal combustion engines

Country Status (5)

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US (1) US3677253A (xx)
JP (1) JPS4833288B1 (xx)
CH (1) CH531129A (xx)
DE (1) DE2100414A1 (xx)
FR (1) FR2075474A5 (xx)

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3754541A (en) * 1969-11-04 1973-08-28 Hitachi Ltd Ignition system for internal combustion engine
US3827418A (en) * 1969-10-15 1974-08-06 C Jacobs Capacitive discharge ignition system having inductor in parallel with ignition coil
US3898588A (en) * 1972-07-03 1975-08-05 Bofors Ab Diode laser pumping
US3910247A (en) * 1973-07-25 1975-10-07 Gunter Hartig Method and apparatus for distributorless ignition
US3918425A (en) * 1972-09-25 1975-11-11 Setco La Chaux De Fonds S A Electronic device serving to supply a load with constant voltage pulses
US4015576A (en) * 1974-04-22 1977-04-05 Junak Edward M Ignition system
US4136659A (en) * 1975-11-07 1979-01-30 Smith Harold J Capacitor discharge ignition system
US4696280A (en) * 1985-10-03 1987-09-29 Niggemeyer Gert G High-tension capacitor-discharge ignition apparatus for internal combustion engines
US4733646A (en) * 1986-04-30 1988-03-29 Aisin Seiki Kabushiki Kaisha Automotive ignition systems
US5060623A (en) * 1990-12-20 1991-10-29 Caterpillar Inc. Spark duration control for a capacitor discharge ignition system
US20060266339A1 (en) * 2005-05-26 2006-11-30 Alger Ii Terrence F Extended Duration High-Energy Ignition Circuit
US20100184323A1 (en) * 2008-11-12 2010-07-22 Panduit Corp. Patch Cord with Insertion Detection and Light Illumination Capabilities

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2637102A1 (de) * 1976-08-18 1978-02-23 Semikron Gleichrichterbau Kondensator-zuendeinrichtung fuer brennkraftmaschinen
JPS61115299U (xx) * 1984-12-27 1986-07-21
JPH0422758A (ja) * 1990-05-18 1992-01-27 Mitsubishi Electric Corp 内燃機関点火装置

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US2651005A (en) * 1951-09-24 1953-09-01 Bendix Aviat Corp Electrical apparatus
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US3302629A (en) * 1964-09-21 1967-02-07 Motorola Inc Capacitor discharge ignition system with blocking oscillator charging circuit
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Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3827418A (en) * 1969-10-15 1974-08-06 C Jacobs Capacitive discharge ignition system having inductor in parallel with ignition coil
US3754541A (en) * 1969-11-04 1973-08-28 Hitachi Ltd Ignition system for internal combustion engine
US3898588A (en) * 1972-07-03 1975-08-05 Bofors Ab Diode laser pumping
US3918425A (en) * 1972-09-25 1975-11-11 Setco La Chaux De Fonds S A Electronic device serving to supply a load with constant voltage pulses
US3910247A (en) * 1973-07-25 1975-10-07 Gunter Hartig Method and apparatus for distributorless ignition
US4015576A (en) * 1974-04-22 1977-04-05 Junak Edward M Ignition system
US4136659A (en) * 1975-11-07 1979-01-30 Smith Harold J Capacitor discharge ignition system
US4696280A (en) * 1985-10-03 1987-09-29 Niggemeyer Gert G High-tension capacitor-discharge ignition apparatus for internal combustion engines
US4733646A (en) * 1986-04-30 1988-03-29 Aisin Seiki Kabushiki Kaisha Automotive ignition systems
US5060623A (en) * 1990-12-20 1991-10-29 Caterpillar Inc. Spark duration control for a capacitor discharge ignition system
US20060266339A1 (en) * 2005-05-26 2006-11-30 Alger Ii Terrence F Extended Duration High-Energy Ignition Circuit
WO2006128031A2 (en) * 2005-05-26 2006-11-30 Southwest Research Institute Extended duration high-energy ignition circuit
US7240670B2 (en) * 2005-05-26 2007-07-10 Southwest Research Institute Extended duration high-energy ignition circuit
WO2006128031A3 (en) * 2005-05-26 2007-11-01 Southwest Res Inst Extended duration high-energy ignition circuit
US20100184323A1 (en) * 2008-11-12 2010-07-22 Panduit Corp. Patch Cord with Insertion Detection and Light Illumination Capabilities
US8267706B2 (en) * 2008-11-12 2012-09-18 Panduit Corp. Patch cord with insertion detection and light illumination capabilities
CN102273023B (zh) * 2008-12-31 2014-02-26 泛达公司 具有插入探测和光照能力的接插线

Also Published As

Publication number Publication date
DE2100414A1 (de) 1971-07-22
JPS4833288B1 (xx) 1973-10-13
FR2075474A5 (xx) 1971-10-08
CH531129A (de) 1972-11-30

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