JPH09268963A - Capacitor discharge type ignition device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide such a capacitor discharge type ignition device for an internal combustion engine as being capable of AC discharge by using a DC-DC converter as a power source. SOLUTION: A damper thyrister Si2 in the forward direction to a charge current flowing from a power source 2 with a DC-DC converter to an ignition energy accumulating capacitor Ci in an ignition circuit 1 is connected in parallel to both ends of the primary coil L1 of an ignition coil. A diode Di2 is connected in reverse parallel to both ends of the thyrister Si1 to discharge the capacitor Ci. The damper thyrister Si2 is controlled to be electrified during charging the capacitor Ci and to be shutoff during discharging the capacitor Ci.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a capacitor discharge type internal combustion engine ignition device using a DC-DC converter for boosting the output voltage of a DC power supply such as a battery as a power supply for charging a capacitor.

[0002]

2. Description of the Related Art A capacitor discharge type internal combustion engine ignition device is
An ignition coil, an ignition energy storage capacitor that is provided on the primary side of the ignition coil and is charged to one polarity by the output of the power supply unit, and discharges the electric charge of the capacitor to the primary coil of the ignition coil when conducting. An ignition circuit having a discharge thyristor provided as described above, a power supply unit that generates a voltage for charging the ignition energy storage capacitor, and an ignition position that gives an ignition trigger signal to the discharge thyristor at the ignition position of the internal combustion engine. And a control device.

As an ignition circuit used in this kind of ignition device, DC is generated in the spark plug when the engine is ignited.
Two types of circuits are used, a discharge method and an AC discharge method in which AC discharge occurs.

FIG. 3 shows an example of the configuration of a capacitor discharge type internal combustion engine ignition device using a DC discharge type ignition circuit. In FIG. 3, 1 is an ignition circuit, 2'is a power supply section, and 3 is ignition position control. It is a device. The illustrated ignition circuit 1 includes an ignition coil IG having a primary coil L1 and a secondary coil L2, which are commonly connected at one end, and the other end of which is grounded.
An ignition energy storage capacitor Ci having one end connected to one end (non-grounded side terminal) of the primary coil of the ignition coil;
A discharge thyristor Si1 is connected between the other end of the capacitor and the ground with its anode facing the capacitor side, and a damper diode Di1 is connected in parallel to both ends of the primary coil L1 of the ignition coil. An ignition plug P attached to a cylinder of the internal combustion engine is connected to the secondary coil L2.

The power supply unit 2'is provided in an electromagnet generator attached to an internal combustion engine and has one end grounded to an exciter coil EX, a non-grounded terminal of the exciter coil and the other end of the ignition energy storage capacitor Ci. And a rectifying diode D1 connected between and.

Further, the ignition position control device 3 has a first signal Vs1 at the maximum advance position and the minimum advance position of the internal combustion engine, respectively.
And the pulsar coil 3A for generating the second signal Vs2 and the ignition position of the internal combustion engine based on the rotation angle information and the rotation speed information obtained from the first signal Vs1 and the second signal Vs2, and the calculated ignition The thyristor S1 is positioned to provide an ignition trigger signal Vi to the thyristor S1.

In the ignition device shown in FIG. 3, in the positive half cycle of the AC voltage induced in the exciter coil EX in synchronism with the rotation of the engine, the diode D1 and the ignition energy storage capacitor Ci are transferred from the exciter coil EX.
And damper diode Di1 and ignition coil primary coil L
A current flows through 1 and the capacitor Ci is charged to the polarity shown. Next, at the ignition position of the engine, when the arithmetic unit 3B generates the ignition trigger signal Vi, the thyristor Si1 becomes conductive, so that the electric charge of the capacitor Ci is discharged through the thyristor Si1 and the primary coil L1 of the ignition coil. A high voltage is induced in the primary coil of. Since the induced voltage of the primary coil is further boosted and a high voltage for ignition is output from the secondary coil L2 of the ignition coil, a spark is generated in the ignition plug P and the engine is ignited.

When the electric charge of the capacitor Ci becomes zero, no current flows in the thyristor Si1. However, the inductance of the primary coil L1 of the ignition coil induces a voltage in the direction in which the current continues to flow in the primary coil. This induced voltage is short-circuited by the damper diode Di1. Therefore, in the ignition device shown in FIG. 3, only a unidirectional current flows through the primary coil L1 of the ignition coil, and a unidirectional current also flows through the secondary coil L2 of the ignition coil. The discharge becomes a DC discharge.

FIG. 4 shows a configuration example of a capacitor discharge type internal combustion engine ignition device using an AC discharge type ignition circuit. In this example, the damper diode Di1 provided in the device of FIG. 3 is removed. , A reverse current-carrying diode Di2 is connected in antiparallel to the discharge thyristor Si1, and the ignition energy storage capacitor Ci and the discharge thyristor S are connected.
An LC resonance circuit is constituted by i1 and the diode Di2 and the primary coil L1 of the ignition coil. Other configurations are similar to those of the ignition device shown in FIG.

In the present specification, "anti-parallel connection" refers to two elements (thyristor Si1 and diode Di2 in the example of FIG. 4) having a characteristic of allowing current to flow in only one direction.
This means connecting the respective currents in the opposite directions and connecting them in parallel.

In the ignition device of FIG. 4, when the ignition trigger signal Vi is applied to the discharging thyristor Si1 and the thyristor becomes conductive, first, a current is passed through the path of capacitor Ci → thyristor Si1 → primary coil L1 → capacitor Ci. Flowing. Even if the electric charge of the capacitor Ci becomes zero, a voltage is induced in the primary coil L1 in the direction in which the current continues to flow, so that the current continues to flow and the capacitor Ci is charged to a polarity opposite to the illustrated polarity. It When the induced voltage in the primary coil L1 becomes zero, a reverse current flows through the route of the capacitor Ci → the primary coil L1 → the reverse current carrying diode Di2 → the capacitor Ci, and the capacitor Ci is charged to the polarity shown in the figure again. It At this time, the thyristor Si1
When an ignition trigger signal is applied to the thyristor S,
i1 conducts again and discharges the electric charge of the capacitor Ci.
Therefore, in the ignition device of FIG. 4, the ignition energy storage capacitor Ci, the discharging thyristor Si1, the diode Di2, the primary coil of the ignition coil are set by sufficiently increasing the signal width of the ignition trigger signal Vi given to the thyristor Si1. An AC oscillating current (AC oscillating current of one cycle or more) can be passed through the LC resonance circuit constituted by L1. Therefore, according to this ignition device, it is possible to cause the spark plug P to generate an AC discharge and prolong the duration of the spark discharge, and it is possible to satisfactorily perform ignition even when using a lean fuel in the internal combustion engine. .

[0012]

In the ignition device shown in FIGS. 3 and 4, the ignition energy storage capacitor Ci is charged by the output of the exciter coil EX provided in the magnet generator. EX is 20
Since it is necessary to induce a high voltage of 0 [V] or more, it is necessary to increase the number of turns, and the provision of the exciter coil inevitably makes the magneto-generator large. Therefore, recently, a DC-DC converter that boosts the output voltage of a DC power supply such as a battery is used, and an ignition energy storage capacitor C is used at the output voltage of the DC-DC converter.
Ignition devices designed to charge i have come into wide use. The DC-DC converter includes a step-up transformer to which a primary current is supplied from a DC power source, a chopper switch that turns on / off the primary current of the step-up transformer, and a chopper switch control circuit that turns the chopper switch on and off at a high frequency. However, since a small ferrite core capable of responding to a high frequency has recently appeared, it becomes possible to configure a step-up transformer in a small size, and a small DC-DC converter is used as a power source of an ignition device. I was able to do it.

Therefore, in the AC discharge type capacitor discharge type internal combustion engine ignition device shown in FIG.
It is possible to replace it with a C-DC converter,
The output voltage induced in the step-up transformer of the DC-DC converter has an intermittent waveform with a fast rising edge, which causes the following problems.

That is, the power supply unit 2'of the ignition device shown in FIG.
-When replaced by a DC converter, when the charging current flows from the converter to the ignition energy storage capacitor Ci, the charging current always passes through the primary coil L1 of the ignition coil, so the capacitor Ci is charged from the DC-DC converter. Each time a voltage with a fast rising direction is output, the inductance of the primary coil L1 causes the capacitor Ci
A spike voltage that rises quickly is generated between the thyristor Si1 side terminal and the ground, and this spike voltage is applied to the thyristor Si1.
Is applied between the anode and the cathode. The time change rate dV / dt of the rise of the spike voltage is calculated by the thyristor Si1.
If the dV / dt withstand capacity of the above is exceeded, the thyristor Si1 becomes conductive even if the ignition trigger signal Vi is not applied, and the capacitor Ci cannot be charged.

As shown in FIG. 4, when the exciter coil EX is used as a power source, when the ignition energy storage capacitor is charged, the induced voltage of the exciter coil rises slowly, so that the anode of the thyristor Si1. The time change rate dV / dt of the voltage applied between the cathodes does not become so large and no problem occurs.

As described above, when the DC-DC converter is used as the power source of the AC discharge type capacitor discharge type internal combustion engine ignition device, the ignition energy storage capacitor C is used.
Since the time change rate dV / dt of the voltage applied between the anode and the cathode of the discharging thyristor Si1 at the time of charging i becomes large and the thyristor may become conductive, the power supply of the AC discharge type ignition device No DC-DC converter has been used as the above, and a capacitor discharge type internal combustion engine ignition device using the DC-DC converter as a power source and having a long discharge duration could not be obtained.

An object of the present invention is to use a DC-DC converter as a power source for charging a capacitor and to generate a spark having a long discharge duration without causing a malfunction of a discharging thyristor when the capacitor is charged. An object of the present invention is to provide a capacitor discharge type internal combustion engine ignition device.

[0018]

According to the present invention, a DC-DC converter for boosting an output voltage of a DC power source, an ignition coil, and one end of a primary coil of the ignition coil are connected to each other by an output of the converter. Of the ignition energy storage capacitor, which is charged to the polarity of, and the charge of the ignition energy storage capacitor of the ignition coil when it is connected and connected between the other end of the ignition energy storage capacitor and the other end of the primary coil. A discharge thyristor for discharging through a primary coil, and a reverse current conducting diode connected in anti-parallel to both ends of the discharge thyristor, an ignition energy storage capacitor, a discharge thyristor and a reverse current conducting diode. And the primary coil of the ignition coil
An ignition trigger signal having a signal width required to flow an AC oscillating current (AC oscillating current of at least one cycle) through the resonance circuit when the ignition circuit including the resonance circuit and the discharge thyristor are electrically connected to each other Internal combustion engine equipped with an ignition position control device for giving to the gate of the discharge thyristor at the ignition position and a converter control device for controlling the converter to stop the output of the converter at least while the ignition trigger signal is generated. It relates to an engine ignition device.

The output of the converter is stopped at least while the ignition trigger signal is generated, because the forward voltage is continuously applied from the converter to the discharging thyristor and the thyristor cannot commutate. This is to prevent it.

In the present invention, the damper thyristor in the direction in which the charging current flowing when the ignition energy storage capacitor is charged by the output of the converter flows in the forward direction is connected in parallel to the primary coil of the ignition coil, At least while the ignition trigger signal is being generated, the damper thyristor is kept in the cutoff state, and the damper thyristor is turned on / off so that the damper thyristor becomes conductive when the ignition energy storage capacitor is charged. A control device was provided.

The DC-DC converter obtains a boosted voltage by turning on and off the primary current of a boosting transformer supplied from a DC power source by means of a chopper switch, and outputs the boosted voltage through a diode. Therefore, the output voltage of the converter has an intermittent waveform.

In the present invention, in order to make the damper thyristor conductive when the ignition energy storage capacitor is charged, an output voltage having a polarity for charging the ignition energy storage capacitor is generated in the step-up transformer of the DC-DC converter. For each time, a trigger signal may be given to the damper thyristor to make the damper thyristor conductive.
The trigger signal may be continuously applied to the damper thyristor over the entire period in which the ignition energy storage capacitor is charged.

The converter control device is generated, for example, at the maximum advance position of the ignition position of the internal combustion engine or at a position slightly advanced in phase from the maximum advance position and delayed in phase from the minimum advance position. A stop command signal generating means for generating a converter output stop command signal that disappears at a position is included, and is configured to stop the output of the converter during the period in which the converter output stop command signal is generated.

In this case, the damper thyristor control device holds the damper thyristor in the cut-off state during the period when the converter output stop command signal is generated, and brings the damper thyristor into conduction when the ignition energy storage capacitor is charged. Configure to allow.

In many cases, the ignition position control device includes a signal generator that generates a first signal and a second signal at a maximum advance position and a minimum advance position of the ignition position of the internal combustion engine, respectively. And a second signal to calculate the ignition position of the internal combustion engine, and at the calculated ignition position, the resonance circuit is operated for a predetermined time (required to reliably ignite the engine). It is configured to provide an ignition trigger signal to the gate of the discharging thyristor having a signal width required to pass an AC oscillating current (during time).

As described above, the damper thyristor is connected in parallel to the primary coil of the ignition coil in the direction in which the charging current flowing when the ignition energy storage capacitor is charged by the output of the converter flows in the forward direction. , At least while the ignition trigger signal is being generated, the damper thyristor is held in the cut-off state, and the damper thyristor is controlled to be turned on / off so that the damper thyristor becomes conductive when the ignition energy storage capacitor is charged. Then, most of the charging current of the ignition energy storage capacitor flows through the damper thyristor and hardly flows in the primary coil of the ignition coil, so when the DC-DC converter outputs a voltage with a fast rise, A high spike voltage is generated and released due to the inductance of the primary coil of the ignition coil. Voltage dV / dt is large it can be prevented from being applied to the use thyristors.

Therefore, according to the present invention, the DC-DC converter is used as the power source for charging the ignition energy storage capacitor, and the ignition energy storage capacitor can be charged without causing malfunction of the discharge thyristor. it can. Further, when the ignition trigger signal is given to the discharging thyristor, the damper thyristor is held in the cut-off state, so that the AC oscillating current can be passed through the LC resonance circuit when the discharging thyristor becomes conductive. Therefore, a spark having a long duration can be generated in the spark plug, and the engine can be satisfactorily ignited even when a lean fuel is used.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a configuration example of a capacitor discharge type internal combustion engine ignition device according to the present invention.

In FIG. 1, 1 is an ignition circuit and 2 is a DC-
Power source unit using DC converter, 3 ignition position control device, 4 charging voltage detection circuit, 5 DC-DC converter when charging voltage of capacitor of ignition circuit exceeds limit value and when ignition operation is performed Is a converter output stop circuit for stopping the output of, and 6 is a damper thyristor trigger signal supply circuit forming a part of the damper thyristor control circuit. The configuration of each part will be described below.

The ignition circuit 1 has a primary coil L1 and a secondary coil L2, one ends of which are commonly connected to each other.
An ignition coil IG whose other end is grounded, an ignition energy storage capacitor Ci whose one end is connected to one end of a primary coil L1 of the ignition coil, the other end of the ignition energy storage capacitor and the other end of the primary coil ( Grounding), a discharge thyristor Si1 for discharging the electric charge of the ignition energy storage capacitor Ci through the primary coil of the ignition coil when the anode is connected in the state of facing the capacitor Ci side and becomes conductive. A resistor Ri1 is connected between the gate and cathode of the thyristor Si1. A spark plug P attached to a cylinder of an engine (not shown) is connected between the other end of the secondary coil L2 of the ignition coil and the ground. The configuration of the ignition circuit 1 up to this point is the same as the configuration of the ignition circuit of the conventional capacitor discharge type ignition device adopting the AC discharge type, but in the present invention, when the ignition energy storage capacitor Ci is charged. The damper thyristor Si2 in the forward direction with respect to the flowing charging current is the primary coil L1 of the ignition coil.
And a resistor Ri2 is connected between the gate and cathode of the thyristor Si2.

In the illustrated ignition circuit 1, when the damper thyristor Si2 is in the cutoff state, the capacitor Ci
An LC resonance circuit is constituted by the discharging thyristor Si1, the diode Di2 and the primary coil L1 of the ignition coil.

The power source unit 2 has a battery 2A as a DC power source whose negative electrode is grounded, a booster circuit 2D including a booster transformer 2B and a chopper switch circuit 2C, a chopper drive command signal generation circuit 2E, and a differential control circuit 2F. And a differentiating circuit 2G and an inverting circuit 2H, and a booster circuit 2D, a chopper drive command signal generating circuit 2E, a differentiating control circuit 2F, a differentiating circuit 2G, an inverting circuit 2H, and a diode D1.
A DC-DC converter is constituted by

Although not shown, the voltage (eg, 14.5 [V]) across the battery 2A is input to the constant voltage power supply circuit through the power switch SW, and a substantially constant DC voltage obtained from the constant voltage power supply circuit. Vcc is applied to the power supply terminal of the circuit described later.

The battery 2A is adapted to be charged through a predetermined charging circuit by the output of a battery charging coil provided in a magnet generator (not shown) attached to the internal combustion engine.

The step-up transformer 2B has a ferrite core wound with a primary coil W1 and a secondary coil W2, and one end of the primary coil W1 is connected to the positive terminal of the battery 2A through a power switch SW. Primary coil W
The drain of an FET (field effect transistor) F1 is connected to the other end of 1, and the source of the FET is grounded. Df is a parasitic diode existing between the drain and source of the FET.

One end of a resistor R1 is connected to the gate of the FET F1 and the other end of the resistor R1 is an NPN transistor TR1.
Is connected to a common connection point between the emitter of the PNP transistor TR2 and the emitter of the PNP transistor TR2. The collector of the transistor TR1 is connected to the positive terminal of the battery 2A through the power switch SW, and the collector of the transistor TR2 is grounded. The bases of the transistors TR1 and TR2 are commonly connected, and a resistor R2 is connected between a common connection point of the bases of both transistors and the collector of the transistor TR1. Transistors TR1 and TR2 and resistor R
A driving circuit for driving the FET F1 is constituted by 1 and R2, and a chopper switch circuit 2C is constituted by the driving circuit and the FET F1. In this chopper switch circuit 2C, the common connection point of the bases of the transistors TR1 and TR2 serves as a drive pulse input terminal, and the drive pulse Vd of positive polarity (rising to a positive potential with respect to ground) is applied to the input terminal. When applied, the transistor TR2 is turned off and the transistor TR1
Becomes conductive and the switch SW is switched from the battery 2A side.
Between the collector and emitter of transistor TR1 and resistor R1
A drive signal is applied to the FET F1 through and. The FET F1 is turned on while the drive signal is being applied (while the drive pulse Vd is being generated), so that the primary current flows through the step-up transformer 2B.

One end of the secondary coil W2 of the step-up transformer 2B is connected to the connection point between the ignition energy storage capacitor Ci and the anode of the thyristor Si1 through the diode D1. At the other end of the secondary coil W2 of the step-up transformer, a charging current detecting diode D2 having an anode grounded is provided, the diode D2 is connected in series to the secondary coil W2, and the emitter is grounded. The base of the signal generating transistor TR3 is connected to the cathode of the diode D2 through the resistor R3. Transistor T
Resistors R4 and R5 are connected between the collector of R3 and the output terminal of the constant voltage power supply circuit (not shown), and between the base of the transistor TR3 and the output terminal of the constant voltage power supply circuit (not shown), and the base of the transistor TR3 is grounded. A resistor R6 is connected between them. In this example, the diode D2, the transistor TR3, and the resistors R3 to R6 form a chopper drive command signal generation circuit 2E.

The base of the differential control transistor TR4 is connected to the collector of the transistor TR3, and the resistor R7 is connected between the base and emitter of the transistor TR4. In this example, the transistor TR4 and the resistor R7 form a differential control circuit 2F.

The collector of the differential control transistor TR4 is connected to one end of the differential capacitor C1, and the other end of the capacitor C1 is connected to the base of the differential pulse generating transistor TR5 whose emitter is grounded. A diode D3 with its anode facing the ground side is connected between the base and emitter of the transistor TR5, and the differential capacitor C
Resistors R8 and R9 are connected between one end of 1 and an output terminal of a power supply circuit (not shown), and between the base and emitter of the transistor TR5. In this example, the differential capacitor C1 and the differential pulse generating transistor TR5
, The diode D3, and the resistors R8 and R9 form a differentiating circuit 2G.

The inverting circuit 2H has an N grounded emitter.
It consists of a PN transistor TR6 and resistors R10 and R11 whose one end is connected to the base of the transistor.
The other end of is connected to the positive terminal of the battery 2A through the power switch SW. The other end of the resistor R11 is grounded, and the collector of the transistor TR5 is connected to the base of the transistor TR6. The collector of the transistor TR6 is connected to the drive pulse input terminal (base of the transistors TR1 and TR2) of the chopper switch circuit 2C. In this example, the differentiation control circuit 2F and the differentiation circuit 2
The G and the inverting circuit 2H constitute a pulse generation circuit which is triggered when the chopper drive command signal is generated and generates a pulse having a predetermined time width as the drive pulse Vd.

The ignition position control device 3 includes a pulsar coil 3A.
An arithmetic unit 3B for calculating the ignition position by using the output of the pulsar coil 3A as an input; and an ignition trigger signal output circuit 3C.
It consists of

The pulsar coil 3A is provided in the signal generator attached to the engine, and as shown in FIG. 2 (A), the engine has a fixed rotation angle position, for example, the maximum advance position θ1 and the minimum advance angle. A first signal Vs1 and a second signal Vs2 are generated at the position θ2, respectively.

In this specification, the position at which the signal reaches a predetermined threshold level (level that can be recognized by the circuit) Vt is defined as the signal generation position.

The arithmetic unit 3B calculates the ignition position at each rotation speed using the rotation angle information obtained from the signals Vs1 and Vs2 and the rotation speed information, and the ignition position signal Vip from the output port B1 at the calculated ignition position. Is output. The ignition position signal Vip has an appropriate shape according to the configuration of the ignition trigger signal output circuit 3C, but in the illustrated example, it is a signal that falls from a high level to a low level (ground potential) at the ignition position. .

As the arithmetic unit 3B, there is an analog type which calculates the ignition position by analog calculation, but in the illustrated example, a digital type which calculates the ignition position by using a CPU is used. In the present invention, it is arbitrary what kind of configuration is used as the arithmetic unit 3B.

In the ignition trigger signal output circuit 3C, the emitter is connected to the output terminal of a constant voltage power supply circuit (not shown), and the base is a CPU constituting the arithmetic unit 3B through a resistor R14.
Of the PNP transistor TR connected to the output port B1 of the
8, a resistor R15 connected between the base and collector of the transistor TR8, a resistor R16 having one end connected to the collector of the transistor TR8, and a diode D4 having an anode connected to the other end of the resistor R16. In this example, the cathode of the diode D4 serves as an ignition trigger signal output terminal, and the cathode of the diode D4 is connected to the gate of the discharging thyristor Si1 of the ignition circuit 1 (the ignition trigger signal input terminal of the ignition circuit). .

In the illustrated ignition trigger signal output circuit 3C, when the ignition position signal Vip is applied, the transistor TR8 becomes conductive, and the ignition trigger signal Vi is supplied between the emitter and collector of the transistor TR8 and the resistor R16 and the diode D4. Output [FIG. 2 (B)]. The rising position of this ignition trigger signal Vi becomes the ignition position of the internal combustion engine. The signal width (time) of the ignition trigger signal Vi is set equal to the duration of the spark discharge generated by the spark plug P during the ignition operation.

The charging voltage detecting circuit 4 includes a voltage dividing circuit formed of a series circuit of resistors R18 and R19 connected between the connection point of the ignition energy storage capacitor Ci and the anode of the thyristor Si1 and the ground, and the resistors R18 and R19. And a resistor R20 whose one end is connected to the connection point of the resistor R20, and the other end of the resistor R20 is input to the input port A2 of the CPU constituting the arithmetic unit 3B. The charging voltage detection circuit 4 sends a detection signal CP proportional to the terminal voltage Vci of the ignition energy storage capacitor Ci to the CP.
Give to U.

The converter output stop circuit 5 is provided to stop the output of the DC-DC converter when the terminal voltage of the ignition energy storage capacitor Ci exceeds the limit value and when the ignition operation is performed. . This converter output stop circuit has an NPN transistor TR7 whose emitter is grounded and whose collector is connected to one end of a differential capacitor C1, a resistor R12 connected between the base and emitter of the transistor TR7, and one end of which is at the base of the transistor TR7. The base of the transistor TR7 is composed of a resistor R13 connected to the arithmetic unit 3B through the resistor R13.
Is connected to the output port B2 of the CPU.

Thyristor trigger signal supply circuit 6 for damper
Is a PNP transistor TR9 having an emitter connected to the output terminal of a constant voltage power supply circuit (not shown), a resistor R21 connected between the base and emitter of the transistor TR9, the base of the transistor TR9 and C constituting the arithmetic unit 3B.
A resistor R22 connected between the PU output port B2 and
Transistor TR9 collector and damper thyristor S
It consists of a resistor R23 connected between the gate of i2.

The CPU constituting the arithmetic unit 3B realizes a stop command signal generating means by executing a predetermined program. This stop command signal generating means is shown in FIG.
As shown in (C), rising at the maximum advance position θ1,
A converter output stop command signal Va which disappears at a position .theta.3 whose phase is delayed by a predetermined angle from the minimum advance position .theta.2 is generated from the output port B2. Minimum advance angle θ2 and signal V
The angle between a and extinction position θ3 is set to be slightly larger than the angle corresponding to the duration of ignition spark when the ignition operation is performed at the minimum advance position θ2 at low speed. The stop command signal generating means also generates the converter stop command signal Va when the charging voltage (terminal voltage) Vci of the ignition energy storage capacitor detected by the charging voltage detection circuit 4 exceeds the limit value.

The converter output stop command signal Va keeps the charging voltage of the capacitor Ci below the limit value and prevents the thyristor Si1 from commutating during the ignition operation so that the charge voltage of the capacitor Ci reaches the limit value. When the converter output stop command signal Va is generated, the converter output stop circuit 5 boosts the voltage of the booster circuit 2D by a signal for stopping the boosting operation of the booster circuit when the ignition output is exceeded. Stop the operation.

The converter output stop command signal Va generated when the ignition operation is performed may be a signal generated in the rotation angle range in which the ignition operation is allowed to be performed, and the maximum advance position θ1 The signal may be generated at a position slightly ahead of the phase and disappear at a position delayed by a predetermined angle from the minimum advance position θ2.

Thyristor trigger signal supply circuit 6 for damper
Turns on the transistor TR9 when the converter output stop command signal Va is not generated to give the trigger signal Vf to the damper thyristor Si2, and when the converter output stop command signal Va is generated, the transistor TR9 is turned on.
Is kept in the cutoff state and the supply of the trigger signal to the thyristor Si2 is stopped. Therefore, the damper thyristor Si2 is
When the rotation angle of the crankshaft of the engine is in the range from the maximum advance position θ1 to the position θ3 where the phase is behind the minimum advance position, and when the charging voltage of the capacitor Ci exceeds the limit value, the trigger signal Is not applied, and in other cases, the trigger signal is applied.
In the illustrated example, a CPU that realizes a stop command signal generating means
And the damper thyristor trigger signal supply circuit 5 constitute a damper thyristor control circuit.

Next, the operation of the ignition device shown in FIG. 1 will be described. In the ignition device of FIG. 1, it is assumed that the electric charge of the differential capacitor C1 is zero when the power switch SW is open. When the power switch SW is open, the transistors TR1 to TR6 are in a cutoff state and the FET F1 is in a cutoff state, so that the step-up transformer 2B stops generating voltage. When the power switch SW is turned on, a constant voltage power supply circuit (not shown) generates a power supply voltage Vcc, and the voltage Vcc
cc is applied to the chopper drive command signal generation circuit 2E.
At this time, no current flows in the secondary coil W2 of the step-up transformer and no forward voltage drop occurs across the diode D2. Therefore, the transistor TR3 is conductive and the transistor TR4 is in a cutoff state. At this time, the power supply voltage Vcc is applied to the differential capacitor C1 through the resistor R8, so that the charging current flows through the differential capacitor C1.
Since the transistor TR5 conducts only while this charging current is flowing, a pulse signal Vd 'falling from the high potential to almost zero potential is generated between the collector and emitter of the transistor TR5. Since the transistor TR6 is in the cutoff state only while the pulse signal Vd 'is generated (while the transistor TR5 is conducting), the transistor TR6 is turned off.
A drive pulse Vd corresponding to an inversion of the pulse signal Vd 'is generated between the collector and emitter of 6. While the drive pulse Vd is generated (while the transistor TR6 is cut off), the transistor TR2 is cut off.
FET F1 through transistor TR1 and resistor R1
Is supplied with a drive signal Vg [FIG. 2 (D)]. As a result, the FET F1 becomes conductive and the primary current flows through the step-up transformer 2B.

In the ignition device of FIG. 1, when the primary current flows through the step-up transformer 2B, the magnetic flux flowing through the core of the transformer 2B is driven so as to have a magnitude close to a saturation value (not saturated). The pulse width of the pulse Vd is set. The pulse width of the drive pulse Vd can be appropriately set by adjusting the time constant determined by the resistance value of the resistor R8 of the differentiating circuit 2G and the electrostatic capacitance of the capacitor C1.

When the driving pulse Vd disappears, the FET F
Since the supply of the drive signal Vg to 1 is stopped, the FET is cut off and the primary current of the step-up transformer 2B is cut off. As a result, a voltage of 200 [V] or more that rises rapidly is induced in the secondary coil W2 of the step-up transformer 2B, and this voltage is given to the ignition circuit 1 through the diode D1. At this time, since the trigger signal is applied to the damper thyristor Si2, the thyristor Si2 becomes conductive, and ignition occurs in the path of the secondary coil W2 → diode D1 → capacitor Ci → damper thyristor Si2 → diode D2 → secondary coil W2. A charging current flows through the energy storage capacitor Ci, and the capacitor Ci is charged to the polarity shown in the figure. As described above, in the present invention, when the ignition energy storage capacitor Ci is charged, the charging current flows through the damper diode Si2, and almost no current flows through the primary coil L1 of the ignition coil. Therefore, the inductance of the primary coil L1 is reduced. This prevents generation of a spike voltage that rises quickly. Therefore, the capacitor Ci can be charged without conducting the discharging thyristor Si1.

When the charging current of the ignition energy storage capacitor Ci is flowing, a forward voltage drop (maximum of about 0.6 V) Vak is applied across the charging current detection diode D2 as shown in FIG. 2 (E). The voltage drop causes a reverse bias between the base and emitter of the transistor TR3, so that the transistor TR3 is turned off and the transistor TR4 becomes conductive. Transistor TR
When 4 becomes conductive, differential capacitor C1 → transistor T
The electric charge of the differential capacitor C1 is discharged along the path between the collector and emitter of R4, the diode D3, and the differential capacitor C1. The charging current flowing from the secondary coil W2 of the step-up transformer to the ignition energy storage capacitor Ci becomes less than a predetermined threshold value (becomes almost zero), and the forward voltage drop across the diode D2 becomes less than a predetermined level. Then, since the transistor TR3 becomes conductive, the transistor TR3 becomes
4 is cut off. At the same time that the transistor TR4 is turned off, the charging current flows through the differential capacitor C1, so that the pulse signal Vd 'is generated from the differential circuit 2G and the drive pulse Vd is generated from the inverting circuit 2H.

When the driving pulse Vd is generated, the FET F
Since the drive signal Vg is applied to 1 and the FET is made conductive, the primary current flows through the step-up transformer 2B. When the drive pulse Vd disappears and the FET is cut off, the primary current of the step-up transformer is cut off and a voltage is induced in the secondary coil W2 of the transformer.

The same operation is repeated thereafter, and every time the charging current (secondary current of the boosting transformer) of the ignition energy storage capacitor Ci becomes less than a predetermined threshold value (or zero), a drive pulse having a constant time width. Vd is generated. When each drive pulse falls to zero, the primary current of the step-up transformer is cut off, a voltage is induced in the secondary coil of the transformer, and the voltage charges the ignition energy storage capacitor Ci.

As the charging of the capacitor Ci progresses, the time during which the charging current flows through the capacitor Ci becomes shorter, so that the generation interval of the drive signal Vg becomes shorter as shown in FIG. 2D. Go. Therefore, the charging interval of the ignition energy storage capacitor Ci becomes shorter as the charging proceeds, and the voltage (charging voltage) Vci across the capacitor Ci rises as shown in FIG. 2 (F). .

When the charging voltage Vci of the ignition energy storage capacitor Ci reaches the limit value, the CPU generates the converter output stop command signal Va, so that the transistor TR7 is used.
Conducts and keeps one end of the differential capacitor C1 at approximately ground potential. Therefore, the differentiating circuit 2G does not generate the pulse signal Vd ', and the boosting operation of the boosting circuit 2D is stopped. As a result, the charging of the ignition energy storage capacitor Ci is stopped, and the charging voltage of the capacitor Ci is prevented from exceeding the limit value.

Ignition position calculation device 3 for ignition position of internal combustion engine
When the ignition position signal Vip is generated, the ignition trigger signal output circuit 3C outputs the ignition trigger signal Vi. Since this ignition trigger signal is given to the thyristor Si1, the thyristor Si1 becomes conductive and discharges the electric charge of the capacitor Ci through the primary coil of the ignition coil IG. As a result, a high voltage for ignition is generated in the secondary coil of the ignition coil IG, a spark is generated in the spark plug P, and the engine is ignited.

In the section where the ignition operation is performed, CP
Since U generates the converter output stop command signal Va,
The transistor TR7 of the converter output stop circuit 5 is turned on to stop the operation of the differentiating circuit 2G. Thus, the operation of the booster circuit 2D is stopped and the voltage is prevented from being applied to the capacitor Ci from the booster circuit, so that the thyristor Si1 is reliably turned off.

When the ignition operation is performed, the converter output constant command signal Va is generated to keep the transistor TR9 of the damper thyristor trigger signal supply circuit 6 in the cutoff state. The supply of the trigger signal is stopped. Therefore, the ignition circuit 1
In the above, the capacitor Ci, the discharging thyristor Si1, the diode Di2 and the primary coil L1 of the ignition coil constitute an LC resonance circuit, and an AC oscillating current flows through the resonance circuit. Therefore, AC current also flows through the secondary coil L2 of the ignition coil, and AC discharge occurs in the spark plug P.

As described above, in the ignition device of the present invention, the damper thyristor Si2 is held in the ON state when the ignition energy storage capacitor Ci is charged by the voltage having a fast rise generated by the DC-DC converter. Since the inductance of the primary coil of the ignition coil prevents a spike voltage from being generated at the thyristor Si1 side terminal of the capacitor Ci, the time change rate dV / dt of the voltage applied between the anode and cathode of the discharging thyristor Si1 is prevented.
It is possible to prevent the thyristor Si1 from becoming conductive due to an excessively large voltage, and the capacitor Ci can be charged without any trouble.

Further, when the ignition operation is performed, in order to keep the damper thyristor Si2 in the cutoff state, the ignition energy storage capacitor Ci, the discharging thyristor Si1, the reverse current energizing diode Di2, and the primary coil L of the ignition coil are held.
An AC oscillating current can be passed through the resonance circuit constituted by 1 to cause the spark plug P to perform AC discharge.
Therefore, a spark having a long duration can be generated, and the engine can be satisfactorily ignited even when a lean fuel is used.

As described above, when the secondary current of the step-up transformer 2B is detected and it is detected that the secondary current is less than the predetermined threshold value (or the secondary current is zero). In the process of supplying a drive pulse Vd of a predetermined time width to the chopper switch circuit 2C to supply a primary current to the step-up transformer 2B, and when the primary current of the step-up transformer is cut off due to disappearance of the drive pulse Vd When the ignition energy storage capacitor Ci is configured to be charged by repeating the process of charging the ignition energy storage capacitor Ci to one polarity with the voltage induced in the coil, the secondary current flows in the step-up transformer 2B. The primary current does not flow when the magnetic flux is flowing in the iron core of the step-up transformer 2B, so that the primary current of the step-up transformer becomes large and Power consumption can be increased the efficiency of the step-up circuit prevents the increase of, or increased heating of the step-up transformer, heat generation at the chopper switch can be prevented or increased.

Further, with the above configuration, since the primary current flows immediately after the secondary current of the step-up transformer 2B becomes zero, the load of the step-up transformer becomes small (the charging of the ignition energy storage capacitor progresses. The shorter the charging current flows, the higher the ON / OFF frequency of the chopper switch. Therefore, the voltage across the ignition energy storage capacitor can be increased almost linearly when the engine is running at high speed, and the charging efficiency of the ignition energy storage capacitor can be improved.

In the above example, when the converter output stop command signal Va is generated, the damper thyristor Si2 is held in the cut-off state, and when the stop command signal is not generated (when the capacitor Ci is charged). ), The damper thyristor Si2 is made conductive. However, while the ignition trigger signal Vi is generated (AC is applied to the LC resonance circuit of the ignition circuit).
It is also possible to keep the damper thyristor Si2 in a cutoff state and to make the damper thyristor Si2 conductive when the ignition energy storage capacitor Ci is charged.

In the above example, the drive pulse Vd is generated by using the differentiating circuit 2G, but the circuit configuration for generating the drive pulse is not limited to the above example. For example,
When the secondary current of the step-up transformer becomes less than the threshold value and the chopper drive command signal generation circuit 2E generates a chopper drive command signal, the monostable multivibrator is triggered to generate a drive pulse. You can also

In the above example, the chopper switch circuit 2
Although C is configured by using the FET as a main switching element (a switching element that turns on / off the primary current of the step-up transformer), the chopper switch circuit can be configured by using another switching element such as a transistor that can be turned on / off as the main switching element. Of course.

[0073]

As described above, according to the present invention, when the ignition energy storage capacitor is charged, the damper thyristor connected in parallel with the primary coil of the ignition coil is brought into conduction, so that the power supply section When a voltage with a high dV / dt is applied, the inductance of the primary coil of the ignition coil prevents a spike voltage from being generated and the discharge thyristor is prevented from conducting.
The C converter can be used to charge the ignition energy storage capacitor without any trouble. Further, when the ignition operation is performed, the damper thyristor is kept in the cut-off state. Therefore, an AC oscillating current is caused to flow in the LC resonance circuit formed on the primary side of the ignition circuit to perform the AC discharge by the ignition plug. It is possible to obtain a spark discharge having a long duration and improve the ignition performance.

[Brief description of drawings]

FIG. 1 is a circuit diagram showing a configuration example of an ignition device according to the present invention.

FIG. 2 is a waveform diagram showing a signal waveform and a voltage waveform of each part of the ignition device of FIG.

FIG. 3 is a circuit diagram showing a configuration example of a capacitor discharge type internal combustion engine ignition device using a magnet generator as a power source.

FIG. 4 is a circuit diagram showing another configuration example of a capacitor discharge type internal combustion engine ignition device using a magnet generator as a power source.

[Explanation of symbols]

 1 Ignition circuit IG Ignition coil Ci Ignition energy storage capacitor Si1 Discharge thyristor Si2 Damper thyristor Di2 Reverse current energizing diode P Spark plug 2 Power supply section 2A Battery 2B Step-up transformer 2C Chopper switch circuit 2D Step-up circuit 2E Chopper drive command signal Generation circuit 2F Differentiation control circuit 2G Differentiation circuit 2H Inversion circuit 3 Ignition position control device 3B Computing device 3C Ignition trigger signal output circuit 4 Charging voltage detection circuit 5 Converter output stop circuit 6 Damper thyristor trigger signal supply circuit

Claims (2)

[Claims] 1. A DC-D for boosting the output voltage of a DC power supply.
A C converter, an ignition coil, an ignition energy storage capacitor whose one end is connected to one end of a primary coil of the ignition coil and which is charged to one polarity by the output of the converter, and the other end of the ignition energy storage capacitor. Connected to the other end of the primary coil and a discharge thyristor that discharges the electric charge of the ignition energy storage capacitor through the primary coil of the ignition coil when electrically connected, and is connected in antiparallel to both ends of the discharge thyristor. An ignition circuit having a reverse current conducting diode, wherein an LC resonance circuit is configured by the ignition energy storage capacitor, a discharging thyristor, a reverse current conducting diode, and a primary coil of an ignition coil, When the discharge thyristor is turned on, the resonance circuit A
An ignition position control device for providing an ignition trigger signal having a signal width necessary for flowing a C oscillating current to the gate of the discharge thyristor at an ignition position of an internal combustion engine, and the converter at least while the ignition trigger signal is generated. In a capacitor discharge type internal combustion engine ignition device including a converter control device that controls a converter so as to stop the output of, the charging current flowing when the ignition energy storage capacitor is charged by the output of the converter is in the forward direction. A damper thyristor connected in parallel to the primary coil of the ignition coil in a flowing direction, and holding the damper thyristor in a cut-off state at least while the ignition trigger signal is generated, for storing the ignition energy To make the damper thyristor conductive when the capacitor is charged, Capacitor discharge engine ignition device comprising; and a damper thyristor controller for turning on and off the thyristor for serial damper. 2. A DC-D for boosting the output voltage of a DC power supply.
A C converter, an ignition coil, an ignition energy storage capacitor whose one end is connected to one end of a primary coil of the ignition coil and which is charged to one polarity by the output of the converter, and the other end of the ignition energy storage capacitor. Connected to the other end of the primary coil and a discharge thyristor that discharges the electric charge of the ignition energy storage capacitor through the primary coil of the ignition coil when electrically connected, and is connected in antiparallel to both ends of the discharge thyristor. An ignition circuit having a reverse current conducting diode, wherein an LC resonance circuit is configured by the ignition energy storage capacitor, a discharging thyristor, a reverse current conducting diode, and a primary coil of an ignition coil, When the discharge thyristor is turned on, the resonance circuit A
An ignition position control device for providing an ignition trigger signal having a signal width necessary for flowing an oscillating current to the gate of the discharge thyristor at the ignition position of the internal combustion engine, and the maximum advance position of the ignition position of the internal combustion engine or the maximum A stop command signal generating means for generating a converter output stop command signal that occurs at a position slightly ahead of the advance position and disappears at a position where the phase is behind the minimum advance position,
A capacitor discharge internal combustion engine ignition device comprising: a converter control device that controls the converter so as to stop the output of the converter while the converter output stop command signal is being generated. A damper thyristor connected in parallel to the primary coil of the ignition coil in a direction in which a charging current flowing when the capacitor is charged flows in a forward direction, and the period during which the converter output stop command signal is generated. A damper thyristor control device for controlling the damper thyristor to be turned on and off so that the damper thyristor is held in a cut-off state and the damper thyristor is brought into conduction when the ignition energy storage capacitor is charged. Capacitor discharge type internal combustion engine ignition device.