JP4367230B2 - Ignition system for capacitor discharge internal combustion engine - Google Patents

Description

  The present invention relates to a capacitor discharge type ignition device for an internal combustion engine.

  A capacitor discharge ignition device is used as an ignition device for an internal combustion engine. This type of ignition device includes, for example, an ignition coil, an ignition capacitor provided on the primary side of the ignition coil, and an ignition power supply unit that charges the ignition capacitor with one polarity as disclosed in Patent Document 1 A discharge switch that conducts when the ignition trigger signal is applied and discharges the electric charge accumulated in the ignition capacitor through the primary coil of the ignition coil, and an ignition trigger signal to the discharge switch at the ignition timing of the internal combustion engine. And an ignition control device.

  In this type of ignition device, the ignition power supply unit includes, for example, a power generation coil provided in a generator driven by an internal combustion engine, a battery, and a converter that boosts the output voltage thereof. With the voltage, the ignition capacitor is charged to 200 to tens of volts. The ignition control device determines the ignition timing of the internal combustion engine with respect to control conditions such as the engine speed, and provides an ignition trigger signal to the discharge switch when the determined ignition timing is detected. The discharge switch conducts when an ignition trigger signal is given, and discharges the electric charge accumulated in the ignition capacitor through the primary coil of the ignition coil, and this discharge induces a high voltage in the primary coil of the ignition coil. This voltage is boosted by the primary / secondary turns ratio of the ignition coil, and an ignition high voltage of about 30 kV is induced in the secondary coil of the ignition coil. Since the high voltage for ignition induced in the secondary coil of the ignition coil is applied to a spark plug attached to the cylinder of the engine, a spark discharge is generated in the spark plug and the engine is ignited.

  In the capacitor discharge type ignition device, a discharge circuit that discharges the charge of the ignition capacitor through the primary coil of the ignition coil is configured on the primary side of the ignition coil by the circuit element including the discharge switch. As this discharge circuit, an AC discharge circuit that allows a discharge current that alternates between positive and negative to the primary coil of the ignition coil and a DC discharge circuit that allows only a one-way discharge current to flow to the primary coil of the ignition coil are used. As described in Patent Document 1, when an AC discharge circuit is configured, diodes are connected in antiparallel to both ends of the discharge switch. When a DC discharge circuit is configured, a damper diode is connected in parallel to the primary coil of the ignition coil.

In a capacitor discharge type ignition device comprising a DC discharge circuit, when the discharge switch is turned on, the primary current (discharge current) flowing from the ignition capacitor through the discharge switch and the primary coil of the ignition coil reaches a peak. When a forward voltage is applied from the primary coil of the ignition coil to the damper diode, a primary current flows from the primary coil through the damper diode. This primary current gradually attenuates and continues to flow even after the ignition operation is completed. The time during which the primary current continues to flow through the damper diode increases as the inductance on the primary side of the ignition coil increases.
Japanese Patent Laid-Open No. 11-13610

  In a capacitor discharge type internal combustion engine ignition device using a DC discharge circuit as a circuit for discharging a capacitor, ignition is performed when the engine speed increases and the ignition frequency (1 / ignition cycle) increases. A new ignition operation is performed before the primary current flowing through the damper diode from the primary coil of the coil is sufficiently attenuated, so the ignition operation is started with the primary current remaining. The rate of change with time of the current generated during the discharge of the minute ignition capacitor is reduced, and the voltage induced in the primary coil of the ignition coil is reduced. When the induced voltage of the primary coil of the ignition coil is lowered, the secondary induced voltage of the ignition coil is lowered, so that the ignition performance is lowered. Especially when an ignition coil with a large primary inductance is used, it takes time to attenuate the primary current flowing through the damper diode, so that the primary current remaining at the start of the ignition operation increases and the engine is running at high speed. The decrease in ignition performance is not negligible.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a capacitor discharge type internal combustion engine ignition device capable of preventing a reduction in ignition performance due to a primary current flowing through a damper diode.

  The present invention relates to a capacitor discharge type ignition device for an internal combustion engine. In the present invention, the ignition coil, an ignition capacitor provided on the primary side of the ignition coil, and the ignition capacitor are charged to one polarity. An ignition power supply unit, a discharge switch that is turned on when an ignition trigger signal is applied, and discharges the electric charge accumulated in the ignition capacitor through the primary coil of the ignition coil, and the ignition timing of the internal combustion engine An ignition control device for providing an ignition trigger signal to the discharge switch, a damper diode, and a damper diode connected in series so as to allow a forward current to flow through the damper diode when in an on state. A damper current control switch that can be turned on and off, and when the ignition capacitor starts discharging at the ignition timing, The damper circuit connected in parallel to both ends of the primary coil of the ignition coil so that the voltage induced in the primary coil is applied to the damper diode in the reverse direction, and the damper current control switch is turned off before the ignition timing And a switch control means for controlling the damper current control switch so as to maintain the damper current control switch at least during the period when the secondary current flows through the ignition coil. It is done.

  As described above, a damper circuit is constituted by the damper diode and the damper current control switch connected in series with the damper diode, and the period during which the damper current control switch is turned off before the ignition timing is set. If this occurs, the ignition operation can be started by starting the discharge of the ignition capacitor in a state where the primary current does not flow through the damper diode, so when using an ignition coil having a large primary side inductance Therefore, it is possible to prevent the ignition performance from being deteriorated due to the presence of the primary current flowing through the damper diode.

  In a preferred aspect of the present invention, a signal generator is provided for generating a reference pulse at a reference crank angle position set at a position advanced from a crank angle position corresponding to the ignition timing of the internal combustion engine. The ignition control device is configured to generate an ignition trigger signal by detecting the ignition timing of the internal combustion engine with reference to the reference crank angle position, and the damper current control switch is in the on state while the drive signal is applied. The switch element is turned off when the drive signal is not applied. In this case, the switch control means stops supplying the drive signal to the damper current control switch when the reference pulse is generated, and resumes supplying the drive signal to the damper current control switch before the ignition timing. Configured to let

  As described above, according to the present invention, a damper circuit is constituted by the damper diode and the damper current control switch connected in series with the damper diode, and the damper current control switch is provided before the ignition timing. Since the period for turning off is generated, it is possible to start the ignition operation by starting the discharge of the ignition capacitor in a state where the primary current does not flow through the damper diode, and the primary side inductance as the ignition coil In the case of using a large one, it is possible to prevent the ignition performance from deteriorating due to the presence of the primary current flowing through the damper diode.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.
The ignition device according to the present invention can be applied to a two-cycle internal combustion engine and a four-cycle internal combustion engine, and can also be applied to an internal combustion engine having any number of cylinders. It is assumed that the engine is a two-cycle engine and the number of cylinders of the engine is 1.

  FIG. 1 shows a configuration of a first embodiment of the present invention. In FIG. 1, reference numeral 1 denotes an ignition coil in which a primary coil 1a and a secondary coil 1b are wound around an iron core. One end of the primary coil 1a of the ignition coil and one end of the secondary coil 1b are grounded, and the other end of the secondary coil 1b is connected to a non-ground side terminal of a spark plug 2 attached to a cylinder of the engine.

  3 is an ignition capacitor connected in series to the primary coil 1a by connecting one end to the other end of the primary coil 1a of the ignition coil, and 4 is parallel to the series circuit of the ignition capacitor 3 and the primary coil 1a. It is the switch for discharge connected to. In the illustrated example, the discharge switch 4 is constituted by a thyristor Th having an anode connected to the other end of the ignition capacitor 3 and a cathode grounded. The thyristor Th constituting the discharge switch becomes conductive when the ignition trigger signal Vi is applied to its gate, and discharges the charge of the ignition capacitor 3 through the primary coil 1a. A resistor 5 and a capacitor 6 are connected in parallel between the gate and cathode of the thyristor Th.

  Reference numeral 7 denotes a generator coil provided in a magnet generator having a rotor attached to a crankshaft of an internal combustion engine and grounded at one end. This generator coil is connected to a positive half-wave voltage Ve1 in synchronization with the rotation of the engine. A negative half-wave voltage Ve2 is generated. A booster circuit 9 is connected to both ends of the power generating coil 7 through a diode 8, and a constant voltage circuit 10 is connected to both ends of the booster circuit 9.

  The step-up circuit 9 includes a step-up switch that conducts when the positive half-wave voltage Ve1 is applied from the power generation coil 7 through the diode 8 and short-circuits the power generation coil 7 through the diode 8, and a short-circuit current that flows through the power generation coil 7. And a boosting switch control circuit that shuts off the booster switch when the set value is reached, and when the booster switch is shut off, a high voltage of two hundred and several tens volts is applied to the generator coil 7. Induce. The positive half-wave voltage of the power generation coil boosted by the booster circuit 9 is applied to both ends of the series circuit of the ignition capacitor 3 and the primary coil of the ignition coil through the diode 11.

  The constant voltage circuit 10 is a circuit that controls the charging voltage Vc of the ignition capacitor 3 so as not to exceed a set value. For example, this constant voltage circuit outputs a positive half-wave output of the power generation coil 7 when it is turned on. A power generation output short-circuit switch that short-circuits the voltage through the diode 8 and a control circuit that turns on the short-circuit switch when the charging voltage Vc of the capacitor 3 exceeds a set value. In this example, the power generation coil 7, the diodes 8 and 11, the booster circuit 9, and the constant voltage circuit 10 constitute a charging power supply unit 12 that charges the ignition capacitor 3.

  A damper circuit 13 includes a damper diode 14 and a damper current control switch 15 connected in series to the damper diode 14. The damper circuit includes a thyristor 4, an ignition coil, and an electric charge accumulated in the ignition capacitor 3. The voltage induced in the primary coil 1a when discharging is started through the primary coil 1a is connected in parallel to both ends of the primary coil 1a in such a direction that the voltage is applied to the damper diode 14 in the reverse direction. The damper current control switch 15 shown in the figure is composed of a MOSFET F1 whose drain is connected to the cathode of the damper diode 14 and whose source is grounded.

  A signal generator 16 generates a reference pulse Vs1 at a reference crank angle position set at a position advanced from a crank angle position corresponding to the ignition timing of the internal combustion engine. For example, the signal generator 16 detects a front end side edge and a rear end side edge in the rotation direction of a reluctator provided in a rotor rotating together with the crankshaft of the engine, and generates pulses having different polarities. In the present embodiment, a pulse generated when the signal generator detects the leading edge of the reluctator is used as the reference pulse Vs1. The pulse generated by the signal generator 16 is input to the ignition control device 17.

  The ignition control device 17 includes a microprocessor, and constitutes an ignition signal generating means 18 and a switch control means 19 by causing the microprocessor to execute a predetermined program.

  The ignition signal generating means 18 is a means for generating an ignition trigger signal Vi to be supplied to the discharge switch 4, and this ignition signal generating means detects, for example, the rotational speed of the engine from the pulse generation interval output from the signal generator 16. A rotational speed detecting means for determining the ignition timing of the internal combustion engine with respect to a control condition such as the rotational speed of the engine, and a reference crank from which the signal generator 16 generates a reference pulse based on the determined ignition timing. It is constituted by trigger signal output means for performing processing for detection based on the angular position and outputting an ignition trigger signal Vi when the ignition timing is detected.

  The switch control means 19 generates a period in which the damper current control switch 15 is turned off before the ignition timing of the internal combustion engine, and at least during the time when the secondary current flows through the ignition coil 1 (spark discharge by the spark plug). This is means for controlling the damper current control switch 15 so as to keep the damper current switch 15 in the ON state. Various methods for determining the timing for turning off the damper current control switch 15 are conceivable. In the present embodiment, when the reference pulse Vs1 is generated, the supply of the drive signal to the damper current control switch is stopped and the ignition is performed. The switch control means is configured to restart the supply of the drive signal to the damper current control switch before the time. Therefore, the damper current control switch 15 is turned off only for a short period before the ignition timing, and is kept on during the other periods.

  In the ignition device shown in FIG. 1, when the discharge switch 4 is in an OFF state, the generator coil 7-the diode 8 and the diode 8 and the positive half-wave induced voltage of the generator coil 7 boosted by the booster circuit 9 are used. 11-Ignition capacitor 3-Ignition capacitor 3 is charged to the polarity shown in the path of primary coil 1a of ignition coil-damper diode 14-damper current control switch 15-generator coil 7. Next, the ignition trigger signal Vi is given to the thyristor Th constituting the discharge switch 4 at the ignition timing set during the period in which the power generating coil 7 outputs a negative half-wave voltage. When an ignition trigger signal is given to the discharge switch 4, the discharge switch 4 is turned on, so that the charge accumulated in the ignition capacitor 3 is discharged through the discharge switch 4 and the primary coil 1a of the ignition coil.

  When the discharge of the ignition capacitor 3 is started, a primary current flows through the primary coil 1a of the ignition coil. At this time, a high voltage is generated in the primary coil 1a to prevent the primary current from flowing, and this voltage is boosted by the step-up ratio between the primary and secondary of the ignition coil to ignite the secondary coil 1b of the ignition coil. High voltage is induced. Since this high voltage is applied to the spark plug 2, a spark discharge is generated in the spark plug and the engine is ignited. The thyristor Th constituting the discharge switch 4 is cut off when its anode current becomes lower than the holding current. The timing for performing the ignition operation is set so that the positive half-wave induced voltage of the power generation coil rises after the discharge switch 4 is cut off.

  Since the voltage first induced in the primary coil 1a when the ignition capacitor starts to be discharged is applied to the damper diode 14 in the reverse direction, no current flows through the damper diode due to the induced voltage. When the primary current passes the peak, the polarity of the induced voltage of the primary coil 1a is reversed, so that the primary current I1 flows from the primary coil 1a through the damper diode 14 and the damper current control switch 15. This primary current gradually decays. If this primary current remains until the next ignition timing, the temporal change rate of the primary current generated when the ignition capacitor starts discharging is reduced accordingly, so that it is induced in the secondary coil of the ignition coil. The voltage drops. When the engine speed increases and the ignition frequency becomes shorter, the primary current remaining at the ignition timing increases, and therefore, a decrease in ignition performance due to residual primary current cannot be ignored.

  In the present invention, a damper current control switch 15 is connected in series with the damper diode 14 to generate a period in which the damper current control switch 15 is turned off before the ignition timing. The residual value of the primary current at the ignition timing is set to zero to prevent the ignition performance from deteriorating at high engine speed.

3A to 3E schematically show the voltage or current waveform of each part of the ignition device of FIG. 1 with respect to the crank angle θ. Hereinafter, the operation of the ignition device shown in FIG. 1 will be described in more detail with reference to this waveform diagram.
3A shows the voltage Vc between the terminal on the diode 11 side (ignition power supply unit side) of the ignition capacitor 3 and the ground, and FIG. 3B shows a pulse generated by the signal generator 16. The signal generator 16 has a negative reference pulse Vs1 at a reference position θ1 set at a crank angle position sufficiently advanced from a crank angle position where the piston of the engine reaches a top dead center (referred to as a top dead center position). And another positive pulse Vs2 is generated near the top dead center position.

  The ignition signal generation means 18 of the ignition control device 17 detects the engine speed from the generation interval of the reference pulse Vs1 (the time required for one rotation of the crankshaft), and the engine ignition timing with respect to the detected speed. Is calculated. This ignition timing is calculated in the form of a time that the ignition timer measures while the crankshaft rotates from the reference position to the crank angle position where the ignition operation is performed. When the reference pulse Vs1 is generated, the ignition control device 17 sets time data for measuring the calculated ignition timing in the ignition timer and starts the measurement, and measures the time data with the ignition timer set. The ignition trigger signal Vi is generated at the crank angle position θi when the above is completed.

  In the example shown in FIG. 3, after the anode current of the thyristor Th constituting the discharge switch 4 becomes equal to or lower than the holding current and the thyristor is turned off, the positive half-wave of the power generating coil 7 at the crank angle position θ3. The induced voltage rises and charging of the ignition capacitor 3 is started. In this example, since the magnet generator is configured with multiple poles and a voltage of a large number of cycles is induced in the generator coil 7 during one rotation of the crankshaft, the ignition capacitor 3 has a positive half of the generator coil 7. Each time a wave voltage is generated, it is charged in stages.

  When the reference pulse Vs1 is generated at the reference position θ1, measurement of the ignition timing is started. At this time, as shown in FIG. 3E, the switch control means 19 uses the MOSFET F1 that constitutes the damper current control switch 15. Since the drive signal Vg applied to the gate is set to zero level and the damper current control switch 15 is turned off, when the primary current I1 remains in the primary coil of the ignition coil, the primary current is cut off. . Due to the interruption of the primary current, a voltage is induced in the primary coil 1a of the ignition coil, and this voltage is superimposed as a surge voltage Va on the voltage Vc between the terminal on the ignition power supply side of the ignition capacitor 3 and the ground. The damper current control switch 15 is returned to the ON state before the crank angle position of the engine reaches the crank angle position θi corresponding to the ignition timing.

  For example, when the reference pulse Vs1 is generated, the switch control means 19 sets a time shorter than the timing data set in the ignition timer to measure the ignition timing in an off-time measuring timer different from the ignition timer. And the drive signal Vg is set to zero level during the time-counting operation of the set time of the off-time measurement timer, and the drive signal Vg is restored when the off-time measurement timer completes the time-measurement operation. And a means for controlling the level of the drive signal Vg so as to return to the level (the level at which the MOSFET is turned on).

  If the timing for turning off the damper current control switch 15 is advanced, the value of the primary current that is cut off when the switch 15 is turned off increases, so that the surge voltage Va increases and the damper that has been turned off The voltage applied to the current control switch 15 increases. When the surge voltage Va increases, it becomes necessary to use a high withstand voltage as the damper current control switch 15 or a snubber circuit for absorbing the surge, which inevitably increases the cost. . In addition, since the high withstand voltage MOSFET has a large internal resistance between the drain and source when it is turned on, if the high withstand voltage MOSFET is used as the damper current control switch 15, the current flowing through the damper circuit is limited and the ignition performance may be reduced. is there. Therefore, the damper current control switch 15 is preferably turned off after the primary current I1 of the ignition coil is sufficiently attenuated. In the present embodiment, the constant section damper current control switch 15 from 72 ° to 48 ° before the top dead center position is turned off.

  When the ignition signal Vi (FIG. 3C) is applied from the ignition signal generating means 18 of the ignition control device 17 to the thyristor Th constituting the discharge switch 4 at the ignition timing, the thyristor is turned on, so that the charge of the ignition capacitor 3 is reduced. Discharge occurs through the thyristor Th and the primary coil 1a, and a primary current I1 flows as shown in FIG. When the primary current reaches a peak, the induced voltage of the primary coil 1a is reversed, and the primary current I1 flows from the primary coil 1a through the damper diode 14 and the damper current control switch 15. This primary current gradually decays. In order to increase the ignition spark duration (duration), when an ignition coil with a large primary inductance is used, when the engine speed increases and the ignition frequency increases (ignition cycle) The primary current I1 remains until the next ignition timing.

  In the ignition device shown in FIG. 1, an ignition device in which the damper current control switch 15 is omitted and the damper diodes 14 are directly connected to both ends of the primary coil 1a of the ignition coil is taken as a comparative example. The waveforms of the voltage Vc across the capacitor, the ignition trigger signal Vi, and the primary current I1 of the ignition coil are shown in FIGS. FIG. 5 shows an enlarged waveform of the waveform of the primary current I1 shown in FIG. In this comparative example, since the primary current continues to flow through the damper diode 14 until the next ignition timing after the ignition operation is performed, the ignition is performed with the primary current I1 remaining at the ignition timing (crank angle position θi). Operation is performed. Here, the primary current remaining at the ignition timing is defined as I1 (start).

  In the ignition device of the comparative example, the ignition frequency, the duration (dur) Td of the discharge generated in the ignition plug, the secondary current I2 of the ignition coil, the secondary no-load voltage V2 of the ignition coil, and the residual primary current The result of measuring the value I1 (start) is shown in FIG. The discharge duration (dur) Td, ignition coil secondary current I2, ignition coil secondary no-load voltage V2, and primary current residual value I1 (start) shown in FIG. Each is as shown by a broken line a in FIGS. As is apparent from these figures, in the ignition device of the comparative example, when the engine speed increases, the residual value I1 (start) of the primary current at the ignition timing increases and the discharge generated by the spark plug continues. In addition to the time Td being shortened, the secondary current I2 and the secondary no-load voltage V2 of the ignition coil are lowered, and the ignition performance is lowered.

  On the other hand, in the ignition device shown in FIG. 1, the ignition frequency, the duration (duration) Td of the discharge generated in the ignition plug, the secondary current I2 of the ignition coil, and the secondary no-load voltage V2 of the ignition coil The result of measuring the residual value I1 (start) of the primary current is as shown in FIG. 7, and the discharge duration Td, the secondary current I2 of the ignition coil, the ignition coil of the ignition coil shown in FIG. The secondary no-load voltage V2 and the residual value I1 (start) of the primary current are illustrated with respect to the ignition frequency as indicated by broken lines b in FIGS. As is clear from these figures, in the ignition device of the present invention, the residual value I1 (start) of the primary current remains zero even when the engine speed increases and the ignition frequency increases. Is done. Therefore, according to the present invention, the duration Td of the discharge generated in the spark plug during high-speed rotation of the engine is not shortened, and the secondary current I2 and secondary no-load voltage V2 of the ignition coil are not reduced. Therefore, it is possible to prevent the ignition performance from deteriorating when the engine rotates at high speed.

  In the embodiment shown in FIG. 1, the ignition capacitor 3 is connected in series to the primary coil 1a of the ignition coil, and the discharge switch is connected in parallel to the series circuit of the ignition capacitor 3 and the primary coil 1a. 4 is connected, but the present invention is not limited to such a configuration, and the ignition capacitor 3 is connected in parallel between the output terminals of the ignition power supply unit 12 as shown in FIG. The present invention can also be applied when connecting and connecting the discharge switch 4 between the ignition capacitor 3 and the primary coil 1a of the ignition coil. In the example shown in FIG. 2, the damper diode 14 is provided in the opposite direction to the example shown in FIG. 1, and its cathode is connected to the non-ground side terminal of the primary coil 1a of the ignition coil. The damper current control switch 15 is composed of a p-channel MOSFET F1 ′, the source of which is grounded, and the drain of which is connected to the anode of the diode 14. In this example, when the MOSFET F1 is turned on, a drive signal Vg having a negative polarity with respect to the source is applied to the gate of the MOSFET.

  The operation of the ignition device shown in FIG. 2 is the same as that of the ignition device shown in FIG. 1 except that the ignition capacitor 3 is charged without going through the damper diode 14 and the damper current control switch 15. .

  In each of the above embodiments, a MOSFET is used as a switch element constituting the damper current control switch. However, this switch element only needs to hold the ON state only while a drive signal is applied. A transistor, an IGBT (insulated gate bipolar transistor), or the like may be used.

  In the above embodiment, the ignition power source unit is configured by the power generation coil in the magnet generator driven by the internal combustion engine and the voltage booster circuit that boosts the voltage induced in the power generation coil. When an ignition power supply unit is configured by an exciter coil wound in a magnet generator and provided with a diode for extracting one half-wave output from the output of the exciter coil, the output of the battery It goes without saying that the present invention can also be applied to the case where an ignition power supply unit that generates a voltage for charging the ignition capacitor by boosting the voltage with a DC-DC converter is used.

  In the above embodiment, the thyristor is used as the discharge switch, but the discharge switch may be constituted by other semiconductor switch elements.

  In the above embodiment, the timing for turning off the damper current control switch is determined by the reference pulse output from the signal generator 16, but the method for determining the timing for turning off the damper current control switch is as follows. The present invention is not limited to the above example. For example, the time when the damper current control switch is turned off may be obtained by measuring the elapsed time from the ignition timing with a timer.

1 is a circuit diagram showing a configuration of a first exemplary embodiment of the present invention. 1 is a circuit diagram showing a configuration of a first exemplary embodiment of the present invention. It is the wave form diagram which showed the voltage or electric current waveform of each part of embodiment of FIG. 1 with respect to the crank angle of an engine. FIG. 2 is a waveform diagram showing a voltage or current waveform of each part with respect to a crank angle when a damper current control switch is omitted from the ignition device shown in FIG. 1. It is the wave form diagram which expanded and showed the principal part of the primary current waveform of the ignition coil shown in FIG. In the ignition device of the comparative example in which the damper current control switch is omitted from the ignition device shown in FIG. 1, the ignition frequency, the duration of the spark discharge generated by the ignition plug, the secondary current of the ignition coil, and the two of the ignition coil It is the graph which showed the result of having measured the next no-load voltage and the primary current which has flowed just before ignition. In the ignition device according to the present invention shown in FIG. 1, the ignition frequency, the duration of the spark discharge generated by the spark plug, the secondary current of the ignition coil, the secondary no-load voltage of the ignition coil, and the flow immediately before ignition. It is the graph which showed the result of having measured the primary current. The graph which compared and showed the relationship between the ignition frequency measured in the ignition device concerning this invention, and the duration of spark discharge, and the relationship between the ignition frequency measured in the ignition device of the comparative example, and the duration of spark discharge It is. It is the graph which compared and showed the relationship between the ignition frequency measured in the ignition device concerning this invention, and a secondary current, and the relationship between the ignition frequency measured in the ignition device of the comparative example. The graph which compared and showed the relationship between the ignition frequency measured in the ignition device concerning this invention, and a secondary no-load voltage, and the relationship between the ignition frequency measured in the ignition device of the comparative example, and a secondary no-load voltage It is. The graph which compared and showed the relationship between the ignition frequency measured in the ignition device concerning this invention, and the primary current just before ignition, and the relationship between the ignition frequency measured in the ignition device of the comparative example, and the primary current just before ignition It is.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ignition coil 2 Spark plug 3 Ignition capacitor 4 Discharge switch 7 Generator coil 9 Booster circuit 10 Constant voltage circuit 12 Ignition power supply unit 13 Damper circuit 14 Damper diode 15 Damper current control switch 17 Ignition control device

Claims (2)

An ignition coil;
An ignition capacitor provided on the primary side of the ignition coil;
An ignition power supply for charging the ignition capacitor to one polarity;
A discharge switch provided to discharge through the primary coil of the ignition coil when conducting an ignition trigger signal and discharging the charge accumulated in the ignition capacitor;
An ignition control device for providing the ignition trigger signal to the discharge switch at an ignition timing of the internal combustion engine;
A damper diode, and a damper current control switch connected in series to the damper diode and capable of on / off control so as to allow a forward current to flow through the damper diode when in the on state. Then, when the discharge of the ignition capacitor is started at the ignition timing, the voltage induced in the primary coil of the ignition coil is applied in the opposite direction to the damper diode so that both ends of the primary coil of the ignition coil A damper circuit connected in parallel to
A period in which the damper current control switch is turned off before the ignition timing is generated, and the damper current control switch is held in the on state at least during the secondary current flows through the ignition coil. Switch control means for controlling the damper current control switch;
An ignition device for a capacitor discharge internal combustion engine comprising: A signal generator for generating a reference pulse at a reference crank angle position set at a position advanced from a crank angle position corresponding to the ignition timing of the internal combustion engine;
The ignition control device is configured to generate an ignition trigger signal by detecting an ignition timing of the internal combustion engine with reference to the reference crank angle position;
The damper current control switch is turned on while a drive signal is applied, and includes a switch element that is turned off when the drive signal is not applied.
The switch control means stops supplying the drive signal to the damper current control switch when the reference pulse is generated, and supplies the drive signal to the damper current control switch before the ignition timing. 2. The ignition apparatus for a capacitor discharge internal combustion engine according to claim 1, wherein the ignition apparatus is configured to be restarted.

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