JP4352223B2 - Ignition system for capacitor discharge internal combustion engine - Google Patents

Description

  The present invention relates to an ignition device for a capacitor discharge type internal combustion engine having means for flowing an ionic current through electrodes of a spark plug and means for detecting the ionic current in order to determine the combustion state of the internal combustion engine. .

  In recent years, in order to purify exhaust gas from internal combustion engines and improve fuel efficiency, it has become necessary to control the ignition timing of the engine with high precision. Information regarding the combustion state at the time is used as a control condition.

  In a spark ignition type internal combustion engine, when a discharge is generated in a spark plug, a flame nucleus is formed when the temperature of the surrounding air-fuel mixture rises and combustion starts, and the flame propagates around it. . At this time, ions are generated near the electrode of the spark plug. The amount of ions generated varies slightly depending on the combustion state of the engine, and the resistance value between the electrodes of the spark plug varies depending on the amount of ions generated. Therefore, by detecting the resistance value between the electrodes of the spark plug immediately after ignition, it is possible to detect the air-fuel ratio state, the suitability of the engine ignition timing, the engine misfire state, and the like. The resistance value between the electrodes of the spark plug can be obtained by detecting an ionic current flowing through the spark plug when a voltage is applied to the spark plug from the outside after applying a high voltage for ignition to the spark plug.

Therefore, as disclosed in Patent Document 1, a capacitor discharge ignition device having means for detecting an ionic current has been proposed. In the capacitor discharge ignition device disclosed in Patent Document 1, a series circuit of a diode, a bias capacitor, and an ion current detection resistor is connected between the non-ground side terminal of the secondary coil of the ignition coil and the ground. The bias capacitor is charged by the spark discharge current flowing through the spark plug and the secondary coil of the ignition coil when the engine is ignited, and the diode is short-circuited after the spark discharge time has elapsed after the ignition is started. The electric charge accumulated in the discharge current is discharged through the secondary coil of the ignition coil, the ignition plug, and the ion current detection resistor, so that the ion current flows. The ion current can be obtained from a voltage drop (detection voltage) generated at both ends of the ion current detection resistor.
JP 2000-45924

  As shown in Patent Document 1, when a bias capacitor used as a voltage source for passing an ionic current is charged with a spark discharge current, the following problems occur.

(A) When no spark discharge occurs in the spark plug during ignition of the internal combustion engine (when the insulation between the electrodes of the spark plug cannot be broken), the bias capacitor cannot be charged. A voltage cannot be applied between the plug electrodes.

(B) Since the bias capacitor continues to discharge during the measurement of the ionic current, the voltage across the capacitor decreases according to the amount of the ionic current that flows. Therefore, even if the resistance value between the electrodes of the spark plug is constant, the detection voltage generated at both ends of the ion current detection resistor is lowered, and it is difficult to accurately detect the ion current. If the capacitance of the bias capacitor is increased and the capacitor is sufficiently charged, the decrease in detection voltage that occurs during ion current measurement can be reduced, and ion current can be detected more accurately. However, as in the ignition device shown in Patent Document 1, when the bias capacitor is charged with the spark discharge current, the capacitor can be charged only for the spark discharge current that has flown at most. Even if the capacitance of the bias capacitor is increased, it is not possible to obtain the effect of suppressing the decrease in the detection voltage.

(C) In the ignition device for an internal combustion engine, the first and second ignition plugs attached to the first cylinder and the second cylinder of the engine, respectively, with both ends of the secondary coil of the ignition coil being ungrounded, In the case of connecting the coil between one end and the ground and between the other end and the ground (when a simultaneous ignition type ignition coil is used), the spark discharge current is generated between the secondary coil of the ignition coil and the secondary coil when the engine is ignited. Since it flows through a closed circuit composed of two spark plugs, it is not possible to charge the bias capacitor with a spark discharge current.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an ignition device for a capacitor discharge internal combustion engine in which an ion current detection voltage can be applied between the electrodes of a spark plug even when spark discharge does not occur during engine ignition. There is.

  Another object of the present invention is to increase the capacity of the bias capacitor to accumulate sufficient energy in the capacitor, and to suppress the voltage drop across the bias capacitor during ion current measurement, thereby detecting the ion current detection accuracy. It is an object of the present invention to provide an ignition device for a capacitor discharge type internal combustion engine that can improve the engine.

  Still another object of the present invention is to charge a bias capacitor and apply an ion current detection voltage between the capacitor and the electrode of the spark plug even when a simultaneous ignition type ignition coil is used. An object of the present invention is to provide a capacitor discharge type internal combustion engine ignition device.

  The present invention provides an ignition coil in which at least one ignition plug is loaded on a secondary coil, an ignition power supply unit that outputs a DC voltage for charging an ignition capacitor, and the ignition power supply unit provided on the primary side of the ignition coil. An ignition capacitor that is charged to one polarity by a voltage obtained from, a discharge switch that conducts when the ignition signal is applied and discharges the charge of the ignition capacitor through the primary coil of the ignition coil, and ignition timing of the internal combustion engine And a control unit having a means for giving an ignition signal to the discharge switch.

  In the present invention, a bias capacitor charged through the backflow prevention diode by the output of the ignition power supply unit, a bias voltage application circuit for applying a bias voltage obtained at both ends of the bias capacitor to both ends of the spark plug, and a bias An ion current detection circuit for detecting an ion current flowing between the electrodes of the spark plug by a voltage is provided.

Further, the control unit controls the ignition power source unit so as to prohibit the ignition power source unit from outputting the DC voltage for charging the ignition capacitor at least from the ignition timing of the internal combustion engine to the time when the detection of the ionic current is completed. Power supply unit control means is provided.

  As described above, when the bias capacitor is charged by the output of the ignition power supply unit, even if no spark discharge is generated in the spark plug at the time of ignition of the engine, the bias capacitor is charged and the ionic current is generated between the electrodes of the spark plug. A voltage for detection can be applied.

  In addition, with the above configuration, even if the capacitance of the bias capacitor is increased, the capacitor can be sufficiently charged, so that the voltage applied to the spark plug during the measurement of the ionic current is prevented from decreasing. Therefore, the detection of the ion current can be performed with higher accuracy than before.

  Further, when configured as described above, the ignition coil is a simultaneous ignition type ignition coil in which one end and the other end of the secondary coil are connected to the non-ground side terminals of the first ignition plug and the second ignition plug, respectively. Even when used, since the bias capacitor can be charged, the capacitor discharge type internal combustion engine ignition device using the simultaneous ignition type ignition coil can be provided with a function of detecting ion current.

When charging of the ignition capacitor is started during the detection of the ionic current, the voltage across the ignition capacitor is applied to the spark plug through the backflow prevention diode, so the voltage across the ignition capacitor is the voltage across the bias capacitor. Becomes higher, the ion current flows from the ignition capacitor side. Since the ion current flows without passing through the ion current detection circuit, the ion current cannot be detected.

As described above, the control unit is provided with an ignition power source control unit so that the ignition power source unit is prohibited from outputting the ignition capacitor charging DC voltage until the detection of the ionic current is completed. Since it is possible to prevent the ignition capacitor from being charged while the ion current is being detected, it is possible to prevent a situation where the ion current flows from the ignition capacitor side and the ion current cannot be detected. it can.

The timing at which the ignition control unit control means starts prohibiting the output of the voltage from the ignition control unit can be advanced to the timing at which charging of the ignition capacitor is completed (the timing at which the voltage at both ends of the ignition capacitor reaches a predetermined set value). it can.

  In the capacitor discharge type internal combustion engine ignition device, when a simultaneous ignition type is used as the ignition coil, one end of the primary coil of the ignition coil is grounded together with the negative output terminal of the ignition power supply unit, and the secondary coil The non-ground side terminal of the first spark plug and the non-ground side terminal of the second spark plug are connected to one end and the other end, respectively.

In this case as well, the ignition capacitor provided on the primary side of the ignition coil and charged to one polarity by the voltage obtained from the ignition power source is connected to the ignition capacitor when an ignition signal is given. A discharge switch for discharging electric charge through the primary coil of the ignition coil and a control unit having means for giving an ignition signal to the discharge switch at the ignition timing of the internal combustion engine are provided. Further, the control unit includes an ignition unit that controls the ignition power source unit so as to prohibit the ignition power source unit from outputting the DC voltage for charging the ignition capacitor at least from the ignition timing of the internal combustion engine to the time when the detection of the ionic current is completed. Power supply control means is provided.

  Here, the spark discharge current that flows when a high voltage is induced in the secondary coil of the ignition coil due to the discharge of the charge of the ignition capacitor is configured to flow from one end side to the other end side of the secondary coil of the ignition coil. (The winding direction of the primary coil and the secondary coil of the ignition coil is set as such).

When the present invention is applied to such an ignition device, one end is connected to the positive output terminal of the ignition power supply unit through a backflow prevention diode having an anode directed to the positive output terminal of the ignition power supply unit. The other end of the bias capacitor is grounded through the ion current detection resistor, and the cathode is connected to the secondary coil side between one end of the bias capacitor and the other end of the secondary coil of the ignition coil. A bias voltage application diode and a voltage applied to the first spark plug and the second spark plug through the bias voltage application diode from the bias capacitor and between the electrodes of the first spark plug and / or the second ignition An ionic current detection circuit for detecting ionic current flowing between the electrodes of the plug from the voltage across the ionic current detection resistor It is preferred. In this case as well, the control unit is provided with an ignition power supply unit so as to prohibit the ignition power supply unit from outputting the DC voltage for charging the ignition capacitor at least from the ignition timing of the internal combustion engine to the time when the detection of the ionic current is completed. Ignition power source control means for controlling is provided.

  When only one spark plug is connected to the secondary coil of the ignition coil, in many cases, one end of the primary coil and one end of the secondary coil are grounded and the other end of the secondary coil is connected to the spark plug. Connected to ungrounded terminal.

  In this case as well, an ignition power supply unit that is provided with the output terminal on the negative polarity side grounded and outputs a DC voltage for charging the ignition capacitor, and provided on the primary side of the ignition coil and obtained from the ignition power supply unit An ignition capacitor that is charged to one polarity by voltage, a discharge switch that conducts when the ignition signal is applied and discharges the charge of the ignition capacitor through the primary coil of the ignition coil, and for discharge at the ignition timing of the internal combustion engine And a controller having means for providing an ignition signal to the switch.

  Also in this case, the spark discharge current that flows when a high voltage is induced in the secondary coil of the ignition coil due to the discharge of the charge of the ignition capacitor is configured to flow from one end side to the other end side of the secondary coil of the ignition coil. It shall be.

When the present invention is applied to such an ignition device for a capacitor discharge internal combustion engine, the anode is directed to the secondary coil side between the other end of the secondary coil of the ignition coil and the non-ground side terminal of the spark plug. One end is connected to the positive polarity side output terminal of the ignition power supply section through the inserted spark discharge current conducting diode and the backflow prevention diode having the anode directed to the positive output side output terminal of the ignition power supply section. A bias capacitor grounded through an ion current detection resistor, and a bias voltage applying diode connected between one end of the bias capacitor and the non-ground side terminal of the spark plug with the anode facing the bias capacitor side And a voltage applied to the spark plug from the bias capacitor through the bias voltage applying diode, and flows between the electrodes of the spark plug. Preferably configured to include an ion current detecting circuit for detecting the that ion current from the voltage across the ion current detection resistor. In this case as well, the control unit is provided with an ignition power supply unit so as to prohibit the ignition power supply unit from outputting the DC voltage for charging the ignition capacitor at least from the ignition timing of the internal combustion engine to the time when the detection of the ionic current is completed. Ignition power source control means for controlling is provided.

  As described above, according to the present invention, when the bias capacitor is charged by the output of the ignition power supply unit, even if no spark discharge occurs in the spark plug during engine ignition, the bias capacitor is charged. A voltage for ion current detection can be applied between the electrodes.

  Further, according to the present invention, even if the capacitance of the bias capacitor is increased, the capacitor can be sufficiently charged by the output of the ignition power supply unit, so that it is applied to the spark plug during the measurement of the ion current. A decrease in the bias voltage can be suppressed, and the ion current can be detected with high accuracy.

  Further, according to the present invention, as the ignition coil, a simultaneous ignition type ignition coil in which one end and the other end of the secondary coil are connected to the non-ground side terminals of the first spark plug and the second spark plug, respectively. Even in this case, since the bias capacitor can be charged, the capacitor discharge type internal combustion engine ignition device using the simultaneous ignition type ignition coil can be provided with a function of detecting the ion current.

Further, according to the present invention, the ignition power source control means is provided in the control unit so that the ignition power source unit is prohibited from outputting the DC voltage for charging the ignition capacitor until the detection of the ionic current is completed . Since it is possible to prevent the ignition capacitor from being charged while the ion current is being detected, it is possible to prevent a situation in which the ion current flows from the ignition capacitor side and the ion current cannot be detected. Thus, ion current can be detected with high accuracy.

  The best mode for carrying out the present invention will be described below with reference to the drawings.

  FIG. 1 shows a configuration of a first embodiment of the present invention in which the present invention is applied to an ignition device using a simultaneous ignition type ignition coil. In FIG. 1, 1 is an ignition coil side including an ignition coil IG. A unit 2 includes an ignition unit including a circuit for controlling a primary current of the ignition coil IG and an ignition power supply unit 2A, 3 a power supply for supplying a power supply voltage to the ignition power supply unit 2A, and 4A and 4B are first cylinders of a two-cylinder internal combustion engine And a first spark plug and a second spark plug respectively attached to the second cylinder. The internal combustion engine may be a two-cycle engine or a four-cycle engine.

  The power source 3 for supplying a power source voltage to the ignition power source unit may be an ignition power coil provided in a generator driven by an engine or a DC power source such as a battery. In the illustrated example, the power source 3 is a DC power source. .

  More specifically, the ignition coil side unit 1 includes an ignition coil IG having a primary coil W1 and a secondary coil W2, a bias capacitor C1, a backflow prevention diode D1, a bias voltage application diode D2, an ion A current detection resistor R1 and a Zener diode ZD are provided. One end of the primary coil W1 of the ignition coil is grounded, and the other end is connected to the ignition capacitor connection terminal 1a. Further, one end and the other end of the secondary coil W2 are connected to the first output terminal 1b and the second output terminal 1c, respectively, and the first output terminal 1b and the second output terminal 1c are respectively connected to the first output terminal of the internal combustion engine (not shown). A non-grounded side terminal of the first spark plug 4A attached to one cylinder and a non-grounded side terminal of the second spark plug 4B attached to the second cylinder are connected via a high voltage cord.

  The bias capacitor C1 is a capacitor provided to apply a bias voltage to the spark plug when detecting the ion current. One end of the capacitor C1 is connected to the cathode of the backflow prevention diode D1, and the other end is connected to the ion current. It is grounded through the detection resistor R1. The anode of the reverse current blocking diode D1 is connected to the power supply voltage input terminal 1d. The bias voltage applying diode D2 is connected between one end of the bias capacitor C1 and the other end of the secondary coil W2 of the ignition coil with the cathode facing the secondary coil W2, and is obtained at both ends of the bias capacitor C1. The applied bias voltage is applied to the first spark plug 4A through the diode D2, the secondary coil W2, and the ion current detecting resistor R1, and the second through the diode D2 and the ion current detecting resistor R1. Applied to both ends of the spark plug 4B.

  In this example, the diode D2 and the resistor R1 constitute a bias voltage application circuit that applies a bias voltage obtained across the bias capacitor C1 across the spark plugs 4A and 4B.

  The Zener diode ZD is connected in parallel to both ends of the ion current detection resistor R1 with its cathode facing the ground side, and the connection point between the bias capacitor C1 and the ion current detection resistor R1 is the detection signal output. Connected to terminal 1e.

  In addition to the ignition power supply unit 2A, the ignition unit 2 includes an ignition capacitor Ca, a thyristor Th that constitutes a discharge switch, a diode Da, a current limiting resistor R2 that limits the charging current of the bias capacitor, and a CPU. And an interface circuit 2C that converts an input signal to the control unit 2B into a signal that can be recognized by a CPU constituting the control unit 2B.

  The ignition power supply unit 2A is a circuit that outputs a DC voltage of two hundred and ten volts for charging the ignition capacitor Ca. In the illustrated example, the ignition power supply unit boosts the DC voltage supplied from the DC power supply. It consists of a circuit (DC / DC converter circuit). As this booster circuit, for example, a known circuit as disclosed in Japanese Patent No. 3191697 can be used.

  The negative output terminal 2A1 of the ignition power supply (boost circuit) 2A is grounded, and the positive output terminal 2A2 is connected to one end of the ignition capacitor Ca. The other end of the ignition capacitor Ca is connected to the ignition coil connection terminal 2a of the ignition unit, and the ignition coil connection terminal 2a is connected to the ignition capacitor connection terminal 1a of the ignition coil side unit 1 through a lead wire.

  A thyristor Th constituting a discharge switch is connected between one end of the ignition capacitor Ca and the ground with its cathode facing the ground side, and a diode Da is connected between the other end of the ignition capacitor Ca and the ground so that the cathode is grounded. Connected towards. The current limiting resistor R2 is provided with one end connected to the positive output terminal 2A2 of the ignition power supply 2A, and the other end of the resistor R2 is connected to the power output terminal 2b of the ignition unit. . The power output terminal 2b is connected to the power voltage input terminal 1d of the ignition coil side unit 1 through a lead wire.

  The ignition capacitor Ca is charged to the illustrated polarity through the diode Da by the ignition power supply DC voltage output from the ignition power supply unit 2A.

  The control unit 2B includes a CPU, calculates the engine ignition timing with respect to various control conditions, and detects the coincidence of the engine crank angle with an angle corresponding to the calculated ignition timing. An ignition signal St is given.

  When an ignition signal is applied to the thyristor Th, the thyristor is turned on, so that the charge accumulated in the ignition capacitor Ca is discharged through the thyristor Th and the primary coil W1 of the ignition coil, and a discharge current I1 indicated by a wavy arrow in the figure. Flows. As a result, a large current instantaneously flows through the primary coil of the ignition coil, so that a high voltage for ignition is induced in the secondary coil W2. Since this high voltage is applied to the spark plugs 4A and 4B, spark discharge occurs simultaneously in both spark plugs, and as shown by the wavy lines in the figure, the secondary coil W2--the spark plug 4B--the ground circuit--the spark plug 4A-- A spark discharge current I2 flows through the path of the secondary coil W2. This spark discharge current I2 flows from the one end side to the other end side of the secondary coil W2 of the ignition coil.

  The ignition power supply unit using the booster circuit can continuously output a DC voltage. However, if the DC voltage is output from the ignition power supply unit, the thyristor that is conducted at the ignition timing of the internal combustion engine. Since it is impossible to turn off Th, this type of capacitor discharge internal combustion engine ignition device applies an ignition signal to the thyristor Th at the ignition timing, and at the same time stops the operation of the booster circuit, The output is stopped.

  Therefore, the booster circuit constituting the ignition power supply unit 2A has an operation stop command input terminal 2A3, and an operation stop command signal Sc is input from the control unit 2B to this input terminal. The booster circuit stops the boosting operation while the operation stop command signal Sc is given from the control unit 2B, and stops the output of the ignition capacitor charging DC voltage.

  A bias capacitor C1 provided in the ignition coil side unit 1 is charged with the polarity shown in the figure through the resistor R2, the diode D1, the Zener diode ZD, and the ion current detection resistor R1 by the output of the ignition power supply unit 2A. . Thus, in the present invention, the bias capacitor C1 is not charged by the spark discharge current, but is charged by the output of the ignition power supply unit 2A. Therefore, even if a capacitor having a large capacitance is used as the bias capacitor C1. The capacitor can be sufficiently charged.

  The backflow prevention diode D1 is provided in order to prevent the voltage of the bias capacitor C1 from being discharged toward the ignition capacitor Ca when the ignition capacitor Ca is discharged, and the voltage across the bias capacitor being lowered. That is, when the backflow prevention diode D1 is provided, the electric charge of the bias capacitor C1 is prevented from being discharged to the ignition capacitor Ca side when the voltage across the ignition capacitor is reduced by the discharge of the ignition capacitor Ca. Therefore, the voltage of the bias capacitor C1 does not drop when the ignition capacitor is discharged.

  Further, since the bias voltage application diode D2 is provided, the high ignition voltage induced in the secondary coil of the ignition coil is not applied to the bias capacitor C1.

  As described above, when the thyristor Th is conducted at the ignition timing of the internal combustion engine and a high voltage for ignition is induced in the secondary coil of the ignition coil, and spark discharge occurs between the electrodes of the spark plugs 4A and 4B, Among the attached cylinders, the gasoline is ignited in the cylinder at the ignition timing to generate a flame nucleus, and the flame propagates in the cylinder and the combustion spreads. As this flame propagation proceeds, the ion concentration in the vicinity of the electrode of the spark plug increases, so that the spark plug and the ion current detection resistor attached to the cylinder at the ignition timing are applied by the bias voltage applied from the bias capacitor C1. An ion current Ii flows through R1.

  In the illustrated example, the cylinder to which the spark plug 4B is attached is at the ignition timing, and the ion current Ii flows through the spark plug 4B by the bias voltage obtained at both ends of the bias capacitor. Since this ion current causes a voltage drop across the ion current detection resistor R1, the ion current can be detected by taking out the voltage Vs across the resistor R1 as a detection signal.

  In the illustrated example, the detection signal output terminal 1e provided in the ignition coil side unit 1 is connected to the detection signal input terminal 2c provided in the ignition unit through a lead wire, and the voltage Vs across the resistor R1 is the interface. The signal is input to the CPU of the control unit 2B as an ion current detection signal through the circuit 2C. In this example, the ion current detection resistor R1, the Zener diode ZD, and the interface circuit 2C constitute an ion current detection circuit.

  The Zener diode ZD prevents an excessive voltage from being input to the interface circuit 2C when the bias capacitor C1 is initially charged, and an excessive voltage is input to the interface circuit due to an unexpectedly large ion current during engine operation. The Zener voltage is set higher than the voltage drop that occurs across the resistor R1 due to the maximum ion current that is expected to flow during steady engine operation.

  In the internal combustion engine, when the spark plugs 4A and 4B are attached to different cylinders of the engine, when one of the two cylinders to which the spark plugs 4A and 4B are attached is at the ignition timing, the other is the ignition timing. Therefore, combustion does not occur simultaneously in both cylinders. For cylinders that are not at the ignition timing, even if a spark discharge occurs at the spark plug, combustion does not occur and ions are not generated near the electrode of the spark plug. Even if a bias voltage is applied from the capacitor C1, no ion current flows. Therefore, even when a simultaneous ignition type ignition coil is used, the ion current flowing through each of the two ignition plugs can be measured by providing only one ion current detection circuit.

  Further, when the control unit 2B is provided with cylinder discrimination means, and the cylinder discrimination means determines which of the two cylinders is the ignition timing at which each of the ignition timings is ignited, It is possible to determine which cylinder's ion current is the measured ion current.

  In this embodiment, the controller 2B is provided with an ignition power supply controller, and the controller stops the operation of the ignition power supply 2A at least from the ignition timing of the internal combustion engine to the completion of detection of the ion current. A command signal Sc is given.

  When the detection of the ionic current is completed and the operation stop command signal supplied from the control unit 2B to the ignition power supply unit 2A disappears, the ignition power supply unit 2A restarts the output of the ignition capacitor charging DC voltage, and the ignition capacitor Ca And the charging of the bias capacitor C1 are started.

  In the embodiment shown in FIG. 1, two spark plugs are attached to different cylinders of the engine. However, both spark plugs may be attached to the same cylinder of the engine. When the spark plugs 4A and 4B are attached to the same cylinder of the engine, the ion current flowing between the electrodes of the spark plug 4A and between the electrodes of the spark plug 4B is detected by the ion current detection circuit.

  In the above embodiment, the ignition power supply unit 2A is configured by a booster circuit that boosts a DC voltage, but an exciter coil provided in a magnet generator attached to the engine, and a diode that rectifies the output of the exciter coil The present invention can also be applied to the case where the ignition power supply unit is configured. In this case, since the ignition power supply unit does not output a voltage at the time of ignition, it is not necessary for the control unit to perform control for stopping the output of the ignition power supply unit.

  In the above embodiment, the simultaneous ignition type is used as the ignition coil. However, the present invention can be applied to the case where only a single spark plug is loaded on the secondary coil of the ignition coil. The configuration of the ignition coil side unit 1 when only one ignition plug 4 is connected to the secondary coil of the ignition coil is shown in FIG.

  In the configuration shown in FIG. 2, one end of the primary coil W1 and one end of the secondary coil W1 are both grounded. Further, a spark discharge current conducting diode D3 is inserted between the other end of the secondary coil W2 of the ignition coil and the non-grounded terminal of the spark plug 4 with the anode facing the secondary coil. . Other points are the same as those of the example shown in FIG.

  In the above embodiment, the ignition capacitor is connected in series to the primary coil of the ignition coil, and the thyristor is connected in parallel to the primary coil via the ignition capacitor, but the positions of the ignition capacitor and thyristor are switched. The present invention can also be applied to a capacitor discharge type ignition device having such a configuration.

  In the above embodiment, the thyristor is used as the discharge switch. However, the present invention can also be applied to the case where the discharge switch is configured by other switch elements such as FETs.

It is the circuit diagram which showed the structure of embodiment of this invention. It is the circuit diagram which showed the structure of the principal part of other embodiment of this invention.

1 ignition coil side unit 2 ignition unit 2A ignition power supply unit 2B control unit 4 ignition plug 4A first ignition plug 4B second ignition plug C1 bias capacitor R1 ion current detection resistor IG ignition coil Ca ignition capacitor Th thyristor ( Discharge switch)
D1 Backflow prevention diode D2 Bias voltage application diode D3 Spark discharge current conduction diode

Claims (4)

An ignition coil in which at least one ignition plug is loaded on the secondary coil, an ignition power supply unit that outputs a DC voltage for charging the ignition capacitor, and a voltage provided on the primary side of the ignition coil and obtained from the ignition power supply unit An ignition capacitor that is charged to one polarity, a discharge switch that conducts when an ignition signal is applied and discharges the charge of the ignition capacitor through the primary coil of the ignition coil, and the ignition timing of the internal combustion engine In an ignition device for a capacitor discharge internal combustion engine comprising a control unit having means for giving the ignition signal to a discharge switch,
A bias capacitor charged through a backflow prevention diode by the output of the ignition power supply unit, a bias voltage application circuit for applying a bias voltage obtained at both ends of the bias capacitor to both ends of the ignition plug, and the bias voltage An ion current detection circuit for detecting an ion current flowing between the electrodes of the spark plug ;
The control unit controls the ignition power source unit to prohibit the ignition power source unit from outputting a DC voltage for charging an ignition capacitor at least from an ignition timing of the internal combustion engine to a timing when the detection of the ion current is completed. An ignition device for a capacitor discharge internal combustion engine comprising ignition power source control means for controlling .   The ignition coil is a simultaneous ignition type ignition coil in which one end and the other end of the secondary coil are respectively connected to the non-ground side terminals of the first ignition plug and the second ignition plug. An ignition device for a capacitor discharge internal combustion engine. An ignition coil in which one end of the primary coil is grounded and the non-ground side terminal of the first spark plug and the non-ground side terminal of the second spark plug are connected to one end and the other end of the secondary coil, respectively, and the negative polarity side An ignition power supply unit that outputs a DC voltage for charging an ignition capacitor, and is provided on the primary side of the ignition coil and is set to one polarity by a voltage obtained from the ignition power supply unit. An ignition capacitor to be charged; a discharge switch that conducts when an ignition signal is applied and discharges the charge of the ignition capacitor through a primary coil of the ignition coil; and the discharge switch at the ignition timing of the internal combustion engine A spark discharge current that flows when a high voltage is induced in the secondary coil of the ignition coil by discharging the charge of the ignition capacitor. The ignition device for capacitor discharge type internal combustion engine that is configured to flow from one end to the other end of the secondary coil of the ignition coil,
One end of the ignition power supply unit is connected to the positive output terminal of the ignition power supply unit through a backflow prevention diode having an anode directed to the positive output terminal, and the other end is grounded through an ion current detection resistor. A bias capacitor, a bias voltage applying diode connected between one end of the bias capacitor and the other end of the secondary coil of the ignition coil with the cathode facing the secondary coil, and the bias capacitor To flow between the electrodes of the first spark plug and / or between the electrodes of the second spark plug by a voltage applied to the first spark plug and the second spark plug through the bias voltage applying diode from An ion current detection circuit for detecting current from the voltage across the ion current detection resistor ,
The control unit controls the ignition power source unit to prohibit the ignition power source unit from outputting a DC voltage for charging an ignition capacitor at least from an ignition timing of the internal combustion engine to a timing when the detection of the ion current is completed. An ignition device for a capacitor discharge internal combustion engine comprising ignition power source control means for controlling . Provided with one end of the primary coil and one end of the secondary coil grounded, the other end of the secondary coil connected to the non-ground side terminal of the spark plug, and the negative output terminal grounded An ignition power supply unit that outputs a DC voltage for charging the ignition capacitor, an ignition capacitor that is provided on the primary side of the ignition coil and is charged to one polarity by a voltage obtained from the ignition power supply unit, and an ignition signal A discharge switch that conducts when given and discharges the charge of the ignition capacitor through a primary coil of the ignition coil; and a control unit that has means for giving the ignition signal to the discharge switch at the ignition timing of the internal combustion engine; A spark discharge current that flows when a high voltage is induced in the secondary coil of the ignition coil due to the discharge of the electric charge of the ignition capacitor. The ignition device for capacitor discharge type internal combustion engine that is configured to flow from one end to the other end of the le,
A spark discharge current conducting diode inserted between the other end of the secondary coil of the ignition coil and a non-grounded side terminal of the spark plug with the anode facing the secondary coil; and A bias capacitor having one end connected to a positive output terminal of the ignition power supply unit through a backflow prevention diode having an anode directed to an output terminal on the positive polarity side, and the other end grounded through an ion current detection resistor; A bias voltage application diode having an anode connected to one end of the bias capacitor and a non-ground side terminal of the spark plug toward the bias capacitor side; and the bias voltage application diode from the bias capacitor Through the voltage applied to the spark plug through the ionic current flowing between the electrodes of the spark plug, A ion current detection circuit for detecting the voltage across the detecting resistor,
The control unit controls the ignition power source unit to prohibit the ignition power source unit from outputting a DC voltage for charging an ignition capacitor at least from an ignition timing of the internal combustion engine to a timing when the detection of the ion current is completed. An ignition device for a capacitor discharge internal combustion engine comprising ignition power source control means for controlling .

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