JPS6155366A - Igniting device of internal-combustion engine - Google Patents

Abstract

PURPOSE:To effect lead of an angle according to the number of revolutions, by selecting the time constants of a third capacitor and a third discharging circuit so that they are completely discharged during low speed rotation when a second voltage is generated and they are prevented from complete discharge during high speed rotation. CONSTITUTION:During low speed rotation, a negative exciter voltage VN1 is increased over that of a capacitor C1 between (e) and (f) of an exciter coil L4, a diode D14 and transistor Tr4 are turned ON and for discharge, and when it exceeds a peak value, disharge is effected through resistance. The Tr4 is turned OFF to turn ON an SCR to ignite an ignition plug P. At a time when VN1 is generated during high speed rotation, the capacitor C1 is not discharged completely, thereby a capacitor C0, charged by a positive exciter voltage, is discharged during generation of a first negative exciter voltage at a next period to ignite the ignition plug P. Thus, ignition is effected in a further lead angle with the increase in the number of revolutions without exercising an influence on an ignition timing by charging of the C0.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is an ignition system for an internal combustion engine with an internal combustion engine of 8g, in particular, an ignition system that is capable of igniting at an advance position when an internal combustion engine rotates at high speed using a relatively front-end circuit. This invention relates to a capacitor discharge type ignition device.

[Prior art]

A capacitor discharge type ignition system charges a capacitor with the voltage generated in the exciter coil of a magneto-type alternator, turns on the thyristor by supplying a gate signal to the thyristor gate at the ignition timing, and discharges the charge accumulated in the capacitor. A high voltage is obtained by discharging it to the ignition coil.

When an internal combustion engine rotates at high speed, ignition must be performed at a more advanced position, and conventional capacitor discharge ignition systems have the disadvantage that the circuit for controlling ignition timing according to the engine speed is complicated. there were.

[Problem that the invention seeks to solve]

The applicant of the present application has filed and proposed an ignition system for an internal combustion engine as described below that improves the above-mentioned drawbacks (hereinafter referred to as the "already proposed ignition system").

FIG. 1 is a circuit diagram showing an example of a previously proposed ignition device. In the figure, LI is the exciting coil of the magneto-type alternator, L2 is the ignition coil, P is the spark plug, and R1-
R4 is a resistor, D1 to D are diodes, co is a discharge capacitor, C1 is a signal capacitor, Tr+ and Tr
Z is a PNP) runlister, and SCR is a thyristor. Exciter coil L1 has three taps a, b, and c, and is configured such that the voltage between taps a and b charges capacitor C8, and the voltage between taps b and c charges capacitor C1. has been done. Note that tap b is grounded.

FIG. 2 shows the waveform of the exciter voltage generated in the exciter coil L. This exciter voltage has a waveform consisting of a negative voltage ■□, a positive voltage ■2 following this negative voltage, and a negative voltage ■8□ following this positive voltage, which continues intermittently as shown in the figure. The amplitude of the positive voltage V, - is the negative voltage MHI
, VH□, and the amplitudes of negative voltages V□ and VH□ are almost equal.

Note that the arrow shown near the exciter coil L+ in FIG. 1 indicates the direction of the positive voltage .

In the ignition system shown in FIG. 1, capacitor C0 is charged by the positive exciter voltage generated between taps a and b of exciter coil L1, and when thyristor SCR (hereinafter simply referred to as SCR) is turned on, capacitor C0 is charged. Discharge occurs, and a high voltage is induced in the secondary circuit of ignition coil L2,
Spark plug P ignites. On the other hand, capacitor CI is charged by the negative exciter voltage generated between taps b and c of exciter coil L, and discharged through resistor R1.

When the exciter voltage between taps b and c of exciter coil L1 is greater than the voltage of capacitor C1, transistor Trl is turned on, thereby transistor Tr2
turns off. Conversely, tap b of exciter coil L1,
When the exciter voltage across C is smaller than the voltage of capacitor C9, transistor Tri is turned off, which turns on transistor Tr2. When the transistor Tri is turned on, a gate voltage is supplied to the gate of the SCR,
If the level of this gate voltage is higher than the trigger level of the SCR, the SCR is turned on.

The basic operation of the ignition system shown in FIG. 1 is as described above, but the operation at low speed rotation and high speed rotation of the internal combustion engine will be explained in detail below.

FIG. 3 is a waveform diagram showing the correspondence among the exciter voltage, the voltages of capacitors C0 and C0, and the trigger voltage to the gate of the SCR during low-speed rotation of the internal combustion engine.

When the rotational speed of the internal combustion engine is low, the period of the exciter voltage becomes large. The discharge rate of capacitor C8 is determined by the time constant of capacitor C5 and resistor R1, and when a negative exciter voltage is generated between taps b and c of exciter coil 'L+, capacitor C8 is completely discharged. The above time constant shall be selected so that

When a first negative exciter voltage VHI is generated between taps b and c, this voltage VNI is greater than the voltage of capacitor C1, so diode D1 is turned on, transistors T, ... are turned on, and resistor R2 is turned on. As a result of the current flowing, the transistor Tr2 is turned off. In this state, tap C1
A current flows through a loop consisting of the diode D2, the emitter heath of the transistor Trl, the diode D1, the capacitor C+, and the tap b, and the capacitor C1 is charged. The capacitor C3 is charged until it becomes equal to the peak value of the negative exciter voltage VNI, and when the exciter voltage ■8□ exceeds the peak value, it starts discharging through the resistor R.

In FIG. 3, the voltage across capacitor CI is shown by a broken line.

After the time t1 when the capacitor C1 starts discharging, that is, the time when the peak value of the negative exciter voltage ■□ occurs, the voltage between taps b and c becomes smaller than the voltage of the capacitor C3. Therefore, diode D1 is turned off, which turns off transistor Trl, and transistor T
,,2 is turned on.

In this state, current flows in a loop consisting of tap C, diode D2, transistor T1, resistors R3, R4, and tap b, and the voltage between taps b and 0 is divided by resistors R3 and R4 at the gate of the SCR. A gate voltage G1 is supplied. This gate voltage G1 increases according to the time and subsequent negative exciter voltage VNI, so the SCR
becomes greater than the trigger level of , thus turning on the SCR. At this point, the capacitor C6 is not yet charged, so the spark plug P does not ignite.

Next, when a positive exciter voltage ■ is generated between taps a and b of exciter coil L, current flows through the primary circuit of tap a1 diode D3, capacitor c0, ignition coil L2, and the loop of tap b. C0 is charged. Capacitor C6 is charged until it is equal to the peak value of the positive exciter voltage, .

Next, tap 5 on the exciter coil L1. ．． 2nd between 0
At the time when the negative exciter voltage VN□ is generated, the capacitor CI is completely discharged as described above, and therefore the exciter voltage VN2 is larger than the voltage of the capacitor C1. In the same operation, the gate voltage G is applied to the SCR at time t2, that is, the time when the peak value of the negative exciter voltage VN□ occurs.
2 is supplied, and SC and R are turned on. When the SCR is turned on, the capacitor C0 is discharged through the SCR and the primary circuit of the ignition coil L2, a voltage is induced in the secondary circuit of the ignition coil L2, and the spark plug P ignites.

In addition, in FIG. 3, the voltage of the capacitor C0 is shown by a broken line.

As described above, when the internal combustion engine rotates at low speed, the spark plug P is ignited at the peak of the second negative exciter voltage.

Next, the operation of the internal engine at high speed rotation will be explained.

FIG. 4 is a waveform diagram showing the correspondence among the exciter voltage, the voltages of capacitors C0 and C1, and the trigger voltage to the SCR gate during high-speed rotation of the internal combustion engine.

When the rotational speed of the internal combustion engine is high, the period of the exciter voltage becomes small. As mentioned above, the discharge rate of capacitor CI is determined by the time constant of capacitor C1 and resistor R3, so whether it is rotating at low speed or high speed,
There is no change in the discharge rate of capacitor C1. Therefore, during high-speed rotation, taps b and c of exciter coil L1
At the time when a negative exciter voltage is generated in between, the capacitor C1 is not completely discharged. In FIG. 4, the voltage across capacitor CI is shown by a broken line.

At time t3 when the first negative exciter voltage NI occurs between taps b and c on the exciter coil, capacitor c1 is not completely discharged as described above, and therefore the voltage of capacitor CI is the negative exciter voltage. Greater than VNI. Therefore, as a result, the transistor T r l is turned off and the transistor T+,2 is turned on, so that the gate voltage G3 applied to the gate of the SCR is equal to the negative exciter voltage VNI.
However, when the voltage VNI becomes larger than the voltage of the capacitor at time t4, the transistor Trl is turned on and the transistor Tr2 is turned off, and as a result, the gate voltage G3 stops being generated in a state that is lower than the trigger level of the SCR. , the SCR is not turned on by this gate voltage G3. With transistors T,.1 on and transistor Tr2 off, capacitor C3 is charged to the peak value of negative exciter voltage VHI. After the time t when the peak value occurs, the negative exciter voltage 1 becomes smaller than the voltage of the capacitor CI, so the transistor Tr+ is turned off and the transistor Tr2 is turned on. As a result, as explained with reference to FIG. 3, a trigger voltage G4 higher than the trigger level is supplied to the gate of the SCR.
CR is turned on. However, at this point, capacitor C
0 is not charged, the spark plug P does not ignite.

The operation of charging the capacitor C0 when the positive exciter voltage 2 is generated is the same as that described in FIG.

At the time t6 when the second negative exciter voltage ■8□ is generated, the capacitor CI is not completely discharged as described above, and therefore the voltage of the capacitor CI is greater than the negative exciter voltage ■8□, and at the time The voltage across the capacitor CI at t6 is greater than the voltage across the capacitor C1 at time L3 due to the period of the exciter voltage. When the voltage of the capacitor CI is greater than the negative exciter voltage vN□, the transistor T,1 is turned off and the transistor Tr2 is turned on, so that the gate voltage G, applied to the SCR gate) rises in accordance with the negative exciter voltage VIJZ. . Then, at time t7 when the SCR trigger level is exceeded, the SCR is turned on, the capacitor c0 is discharged, and the spark plug P is ignited. Even after turning on the SCR, the gate voltage rises according to the negative exciter voltage ■8□, and at time t8 when the exciter voltage ■8□ becomes larger than the voltage of the capacitor CI, the transistor T11 is turned on and the transistor Tr2 is turned off. Generation of the trigger voltage G is stopped.

In this case, it is necessary to ensure a period between times t and t so that the gate voltage Gs can exceed the trigger level.

After time 1u when transistor Tri is turned on and transistors T, 2 are turned off, capacitor cl is charged,
Then, at time t, when the peak value of the negative exciter voltage ■,42 occurs, the transistors T,,1 are turned off, and the transistor Tr! As a result, a trigger voltage Gb higher than the trigger level is supplied to the gate of the SCR, and the SCR is turned on. However, since the capacitor C0 has already been discharged at this point, the spark plug P is not discharged.

As described above, when the internal combustion engine rotates at high speed, the spark plug P is ignited at a time before the peak of the second negative exciter voltage, in this example, at time t7. Therefore, the ignition timing when the engine is rotating at high speed is advanced than the ignition timing when the engine is rotating at low speed, and automatic advance is achieved.

FIG. 5 is a diagram showing an example of the relationship between the ignition timing of the ignition device of this example and the rotational speed of the internal combustion engine. For example, rotation speed 3500
At low speeds below r, p, m, the ignition timing is 1 before top dead center.
3°, but 3500 r.

At high speeds above p and m, the ignition timing is 2 minutes before top dead center.
3°, and the ignition is in the advanced position.

In the above ignition device, small signal transistors can be used for the transistors Trl and Tr2, which makes it cheaper, and a film capacitor with less variation in capacitance can be used for the signal capacitor C1, so
Reliability can be improved.

In the ignition device shown in FIG. 1 described above, the power source for charging the signal capacitor C1 is separately taken out using the intermediate tap b of the exciter coil L. Therefore, it is necessary to wind a coil only for signals (the coil between taps b and c), and in order to lower the trigger level, the coil for charging capacitor 00 (tap a) must be wound.
The number of turns must be the same as the number of turns of the coil (between coils , b).

FIG. 6 shows an ignition device in which the signal coil and the charging coil for the capacitor C0 are made common so that the same coil can be used in order to solve this problem. In the figure, elements corresponding to those of the ignition system shown in FIG. 1 are designated by the same reference numerals. In the figure, L3 is an exciter coil that is commonly used as a signal coil and a charging coil for capacitor C6, R5 to R7 are grinding resistors, and D6 to DII are diodes. In this circuit, especially the diode D
Reference numeral 6 is used to partially short-circuit the power supply for signals so that the voltage for signals does not rise too much when the internal combustion engine rotates at high speed.

In this ignition system, capacitor C0, exciter coil L3, diode D? , the capacitor C6, the primary circuit of the ignition coil L2, and the loop of the exciter coil L3. When the SCR is on, the SCR and the diode D are charged.
It is discharged through the primary circuit of IG and ignition coil L2. The capacitor CI is charged in a loop including the exciter coil L3, the emitter of the transistor Trl, the diode D1, the capacitor CI, the diode D10, and the exciter coil L3, and is discharged through the resistor R.

Transistors Trl and T,2 act in the same manner as the ignition device shown in FIG. turns off.

Conversely, when the negative exciter voltage generated in the exciter coil L3 is smaller than the voltage of the capacitor CI, the transistors T, ... are turned off, thereby turning off the transistor T.
r2 turns on. When transistor Tr2 is turned on, exciter coil L3, transistor T1□, resistor R6,
A current flows through the loop of diode D7 and exciter coil/L/L3, which applies gate voltage to the gate of the SCR, turning the SCR on. The operation during low-speed rotation and high-speed rotation is basically the same as the ignition system shown in Figure 1, but in particular, during high-speed rotation, care is taken to prevent the signal voltage, that is, the negative exciter voltage, from rising too much. , the exciter coil L3 is partially shunted by a diode D6.

According to this ignition device, there is no need to newly wind a signal exciter coil, so it is possible to reduce costs. Furthermore, since the signal voltage is high during low speed rotation, the trigger level of the SCR can be lowered.

Furthermore, since the increase in signal voltage during high-speed rotation is suppressed (from 150V to 80V, for example), this is advantageous in terms of the withstand voltage of the transistor.

In the ignition device shown in FIG. 6 described above, the transistor Tr2 is connected in series to the gate of the SCR to perform switching of the SCR. Therefore, the transistor T
, 2 are off, a signal voltage, that is, a negative exciter voltage is applied to the transistor Tr2. Therefore, the signal voltage must be taken into account when determining the withstand voltage of the transistor T1z.

FIG. 7 shows an ignition device in which there is no need to consider the signal voltage with respect to the withstand voltage of the transistor, and in which the number of transistors can be reduced to one. In the figure, elements corresponding to those of the embodiment shown in FIG. 6 are designated by the same reference numerals. In the figure, Tr3 is an NPN transistor, R,
and R7 are resistors, and DI2 is a diode. In this circuit, the transistor Trff is provided in parallel with the gate of the SCR.

In this ignition system, capacitor C0 is charged in a loop of exciter coil L3, diode D7, capacitor C6, primary circuit of ignition coil L2, and exciter coil L3, and when SCR is on, SCR, diode D
It is discharged through the primary circuit of the IOs ignition coil L2. Capacitor C1 is an exciter coil 3, capacitor c
1, diode I)+z, base-emitter of transistor T, 3, diode D1. , exciter coil L3
It is charged in the loop and discharged through the resistor R.

When the negative exciter voltage generated in the exciter coil L3 is larger than the voltage of the capacitor C8, the diode D1□ is turned on, so the transistor Tr3 is turned on, and conversely, the negative exciter voltage generated in the exciter coil L3 is When the voltage is lower than the voltage of the capacitor→JC+, the diode D1□ is turned off, and therefore the transistor Tr3 is turned off. When the transistor Tr3 is turned off, a current flows in a loop including the exciter coil Li, the resistor RIl, the resistor R9% diode D1, and the exciter coil, and a gate voltage is supplied to the gate of scR, turning on the SCR.

As is clear from the above basic operation, the operation of this ignition device when the internal combustion engine rotates at low speed and at high speed is the same as that described in FIGS. 3 and 4. That is, during high-speed rotation, the ignition is ignited at a more advanced position than during low-speed rotation.

According to this ignition device, switching is performed by providing a transistor 'rr:+ in parallel with the gate of the SCR, so even when the transistor T- is off, the transistor S
Since only the voltage drop (for example, 0.6 V or less) between the gate and cathode of the CR, that is, the PN junction, is applied, there is no need to consider the withstand voltage of the transistor. Furthermore, since only one transistor is required, costs can be reduced. Furthermore, since there is no need to reduce the signal voltage (negative exciter voltage) for the withstand voltage of the transistor when the internal combustion engine rotates at high speed, the number of parts can be reduced.

In the ignition system shown in FIG. 7 described above, the capacitor C
6 is charged and SCR is off, capacitor c, , SCR, diode D1°, primary circuit of ignition coil L2, voltage loop of capacitor C6, and anode-gate of capacitor C0, SCR. , the gate series resistor R3, the primary circuit of the ignition coil L2, and the voltage loop of the capacitor C8 are formed, and these voltage loops apply a forward voltage to the SCR that is the sum of the voltage of the capacitor C0 and the voltage of the gate series resistor R8. It turns out. Therefore, an SCR with high forward breakdown voltage is required.

FIG. 8 shows an embodiment in which the forward withstand voltage of SCH can be lowered. In the figure, elements corresponding to those of the ignition system shown in FIG. 7 are designated by the same reference numerals. In the figure, T, , 4 are PNP l-run listers, R1° and R
1 is a resistor, and DI:+ and DI4 are diodes.

In this circuit, capacitor C0 is charged and S
When CR is off, capacitor C6, SC
R, diode DIO% Since only the voltage loop of the primary circuit of the ignition coil L2 and the capacitor C0 is formed, the voltage of the capacitor C0 is only applied as a forward voltage to the SCR. Therefore, compared to the embodiment of FIG.
For example, the CRO forward breakdown voltage can be lowered from 600V to 400V.

In this ignition system, capacitor C0 is charged in a loop of exciter coil L,3, diode D1, capacitor C0, primary circuit of ignition coil L2, and exciter coil L3, and when SCR is on, SCR, diode DIG, ignition It is discharged through the primary circuit of coil L2.

The capacitor is charged in a loop consisting of the exciter coil L3, the emitter base of the transistor Tra, the diode D4, and the capacitor C11, and is discharged through the resistor R1.

When the negative exciter voltage generated in the exciter coil L3 is higher than the voltage of the capacitor C8, the diode DI4 is turned on, and therefore the transistor Tr4 is turned on. Conversely, when the negative exciter voltage generated across the exciter coil Tr3 is smaller than the voltage of the capacitor CI, the diode DI4 is turned off, and therefore the transistor Tr4 is turned off. When transistor Tr4 turns off, exciter coil L3, resistor R11, resistor R1°,
A current flows through the loop of the exciter coil, and gate voltage is supplied to the gate of the SCR, turning the SCR on.

As is clear from the above basic operation, the operation of this ignition device when the internal combustion engine rotates at low speed and at high speed is the same as that described in FIGS. 3 and 4. That is, during high-speed rotation, the ignition is ignited at a more advanced position than during low-speed rotation.

According to this ignition device, when turning on the SCR, a loop current flows through the exciter coil L:l, the resistor RI+, the resistor Rio, and the exciter coil L3, and a gate voltage is supplied to the gate of the SCR, but the SCR is turned on. As a result, capacitor C0 is discharged and SCR, diode D1
°, a discharge current flows through the primary circuit of the ignition coil L2. This discharge current flows in the opposite direction to the current that supplies the gate voltage to the SCR, resulting in the gate of the SCR being reverse biased. Therefore, when the gate voltage is low, the SCR is not turned on and the trigger rotation speed increases.

In other words, there is a problem that the rotational speed at which the SCR starts to turn on becomes high.

FIG. 9 shows an ignition device that solves the above problems. In the figure, elements corresponding to those of the ignition system shown in FIG. 8 are designated by the same reference numerals.

In the figure, R1□ is a resistor and DIS is a diode.

In this circuit, the current for supplying the gate voltage to the SCR is passed through the exciter coil L3, the resistor R, the resistor RI2,
The exciter coils and flows in a loop. Capacitor C
The discharge current of 0 flows through the primary circuit of the SCR and ignition coil L2, but it does not cancel the above current for supplying the gate voltage, so the gate of the SCR is not reverse biased, and therefore the trigger rotation speed is There is no problem of rising.

In this ignition system, the capacitor C6 is charged in the loop of the exciter coil L3, the diode D7, the capacitor C0, the primary circuit of the ignition coil L2, the diode 1)+s, the exciter coil, and when the SCR is on,
It is discharged through the primary circuit of SCR1 ignition coil L2.

The capacitor C1 is charged in a loop including the exciter coil L3, the emitter base of the transistor Tr4, the diode D14, the capacitor C1, and the exciter coil L3, and is discharged through the resistor R1.

When the negative exciter voltage generated in the exciter coil L is greater than the voltage of the capacitor C1, the diode DI4 is turned on, and therefore the transistor T□ is turned on. Conversely, when the negative exciter voltage generated in the exciter coil La is smaller than the voltage of the capacitor CI, the diode DI4 is turned off, and therefore the transistors T and 4 are turned off. When the transistor Tr4 is turned off, an exciter coil is formed, a current flows through a loop of the resistor R11, the resistor R1□, and the exciter coil 3, and a gate voltage is supplied to the gate of the SCR, turning the SCR on.

As is clear from the above basic operation, the operation of this ignition device when the internal combustion engine rotates at low speed and at high speed is the same as that described in FIGS. 3 and 4. That is, during high-speed rotation, the ignition is ignited at a more advanced position than during low-speed rotation.

According to the previously proposed ignition system explained above, the capacitor is 0.
Since ignition is performed while the second negative exciter voltage is generated after zero charging, the influence of charging of capacitor C0 acts to retard the ignition timing when the internal combustion engine rotates at high speed. On the other hand, an increase in the rotational speed of the internal combustion engine during high-speed rotation causes the exciter voltage generated in the exciter coil to become steeper, which acts to advance the ignition timing. However, due to the influence of the charging of the capacitor C0 mentioned above, the ignition timing remains constant during high-speed rotation even if the rotational speed increases, as shown in FIG. Essentially, it is desirable in terms of performance for the ignition timing to advance with the upper limit of the rotational speed during high-speed rotation.

[Object and structure of the invention]

An object of the present invention is to provide an ignition device that eliminates the influence of charging of the capacitor C0 and advances the ignition timing as the rotational speed increases when the internal combustion engine rotates at high speed.

P within the present invention! The ignition device of the engine is driven by an internal combustion engine and includes a power source that intermittently generates a voltage consisting of a continuous negative first voltage, a positive voltage, and a negative second voltage, and a second power source that is charged by the positive voltage. a first charging circuit having one capacitor; a first discharging circuit having a thyristor for discharging the first capacitor; a second charging circuit having a second capacitor charged by the positive voltage;
a second discharge circuit for discharging the capacitor;
and a third charging circuit having a third capacitor charged by a second voltage, and a third discharging circuit discharging the third capacitor, when the second voltage of the quality is greater than the voltage of the third capacitor. a first circuit for charging a third capacitor and generating a trigger signal to the thyristor when the second voltage of the quality is less than the voltage of the third capacitor; a second circuit that detects the charging voltage of the thyristor and prevents the thyristor from turning on while the negative second voltage is being generated; and a third circuit that discharges the second capacitor when the negative second voltage is generated. , the time constants of the third capacitor and the third discharge circuit are such that when the negative second voltage is generated when the internal combustion engine is running at low speed, the third capacitor is completely discharged, and when the internal combustion engine is rotating at high speed, the third capacitor is completely discharged; The third capacitor is selected so as not to be completely discharged when the second voltage is generated.

〔Example〕

Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 10 is a circuit diagram showing one embodiment of the present invention. In this embodiment, the ignition device shown in FIG.
and a charge/discharge circuit has been added. therefore,
Elements corresponding to those in FIG. 9 are designated by the same reference numerals. In the figure, L4 is an exciter coil, R13, R
I4 and RI5 are resistors, DI6 is a diode, C7 is a capacitor, and 5CR1 and 5CRz are thyristors. Exciter coil L4 has three taps d, e, , f
When a positive exciter voltage is generated, capacitor C2 is charged by the voltage between taps d and e, capacitor C9 is charged by the voltage between taps e and 1, and when a negative exciter voltage is generated, tap e is charged. , f is configured to charge the capacitor C1.

11 and 12 show the exciter voltage of exciter coil L4, the voltages of capacitors C0 and CI, and the gate of SC'R during low-speed rotation and high-speed rotation of the internal combustion engine, in order to explain the operation of this embodiment. FIG. 3 is a waveform diagram showing the correspondence of trigger voltages to and from each other. In addition, the first
In Figure 2, the period of the exciter voltage during high-speed rotation is the first
Although the period is smaller than the period of the exciter voltage during low speed rotation in FIG. 1, the same period is shown for clarity of the drawing.

When a positive exciter voltage is generated in the exciter coil L4, a positive exciter voltage between taps e and f is generated at tap e, diode D7, capacitor C6, the primary circuit of ignition coil L2, resistor R11, and tap f. At the same time that capacitor C0 is charged by the loop, the positive voltage between taps d and e causes R2b d, diode D+a, and resistor RI
4. Capacitor C2 is charged by the loop of capacitor C2 and tap e. The charged capacitor C2 gradually discharges via the gate and cathode of the resistor R+s, SCR. On the other hand, while a positive exciter voltage is being generated, capacitor CI is discharging through resistor R1.

When a second negative exciter voltage VH□ is generated between the taps e and f of the exciter coil L4, the negative exciter voltage VN2 is , 5CRI, are added in a loop of tap e. Since a gate voltage is supplied to the gate of 5CR1 by the charged capacitor C2, SCR is turned on and current flows in the above loop. As a result, the transistor Tr6 is turned on, and further, the current supplies the gate voltage to SCRz, turning on 5CR2, and the capacitor C7 is rapidly discharged via SCRz and SCR.

While negative exciter voltage ■8□ is generated, SCR
, continues to be on, so the transistor Tr4
continues to turn on. As a result of the transistor T f 4 being on, the gate and cathode of the SCR are short-circuited, so the SCR is never turned on regardless of the voltage of the capacitor C1. Thus, no ignition occurs during the generation of the second negative exciter voltage.

On the other hand, while the negative exciter voltage VH□ is being generated, the capacitor C1 is charged to the peak value of the negative exciter voltage VNZ in the loop consisting of the tap f, the emitter base of the transistor Tr4, the diode DI4, the capacitor C7, and the tap e. , is discharged through the resistor R1. Capacitor C
The discharge rate of I is determined by the time constant of capacitor CI and resistor R, so when the internal combustion engine rotates at low speed,
As shown in the figure, by the time the negative exciter voltage VNI occurs in the next cycle, the capacitor CI has been completely discharged, and during high-speed rotation, the capacitor CI has completely discharged as shown in Figure 12. The above time constant is selected so as not to cause the problem to occur.

When a first negative exciter voltage V0 is generated between taps e and f during low speed rotation, this voltage VNI is applied to the capacitor C.
1, the diode DI4 is turned on and the transistor Tr4 is turned on. In this state, a current flows through a loop consisting of the tap f1, the emitter base of the transistor Tr4, the capacitor C1, and the tap e, and the capacitor C1 is charged. The capacitor C1 is charged until it becomes equal to the peak value of the negative exciter voltage V N (, and when the exciter voltage ■□ passes its peak value, it starts discharging through the resistor R1. In FIG. 11, the capacitor C1 The voltage of is shown by the dashed line.

After time tI when capacitor C1 starts discharging, that is, after the time when the peak value of negative exciter voltage VNI occurs, the voltage between taps e and f becomes smaller than the voltage of capacitor C1. Therefore, diode D14 is turned off,
This turns off transistor TI-a. In this state, tap f, resistor Rl 1, resistor R13, tap e
A current flows in the loop, and a gate voltage G is supplied to the gate of the SCR. This gate voltage G is at time 1.
Since it becomes larger according to the subsequent negative exciter voltage VNI, it becomes larger than the trigger level of SCR, and therefore S
Turn on CR and spark plug P ignites.

At time t2, when the first negative exciter voltage VNI is generated between the cups e and f during high-speed rotation, the capacitor C1 is not completely discharged (see FIG. 12). Therefore, at time t2, the negative exciter voltage V N l is smaller than the voltage on capacitor C3. For this reason, the diode DI4
is turned off, and the transistor Tr4 is turned off. As a result, the gate voltage G2 applied to the gate of the SCR rises in accordance with the negative exciter voltage VNI, and the gate voltage G2
2 exceeds the SCR trigger level at time L3, the SC
Turn on R and ignite spark plug P.

After the SCR is turned on, the gate voltage rises in accordance with the negative exciter voltage VNI, and at time t4 when the exciter voltage ■□ becomes larger than the voltage of the capacitor C3, the transistor T□ is turned on and generation of the trigger voltage G2 is stopped.

After time t4, capacitor C1 is charged to the peak value of voltage V□. Peak value occurrence time t
, thereafter, the voltage of capacitor C1 is negative exciter voltage V
Since it becomes larger than NI, Tr4 turns off and SCR
A gate voltage G3 is supplied to the gate voltage G3. This gate voltage G rises according to the negative exciter voltage ■Nl, and the SCR
However, since the capacitor C0 has already been discharged by the gate voltage G2, it is no longer discharged, and therefore the spark plug P does not ignite.

As explained above, according to this embodiment, when the second negative exciter voltage ■8□ is generated, the gate and cathode of the SCR are short-circuited, so the SCR is not turned on, and therefore the second The negative exciter voltage v, 4□ does not cause ignition, and the negative first exciter voltage of the next cycle ■
8. It will be ignited by. Therefore, since it is not affected by the charging of the capacitor C6, when the internal combustion engine rotates at high speed, the ignition timing advances as the rotational speed increases.

FIG. 13 is a diagram showing an example of the relationship between the ignition timing of the ignition device of this embodiment and the rotation speed of the internal combustion engine.

For example, at low speeds below 350 Or, p, m, the ignition timing is 13 degrees before top dead center;
, p, m, the position is 23 degrees before top dead center, and the ignition timing advances as the rotational speed increases.

〔effect〕

According to the invention, the capacitor C6 charged by the positive exciter voltage is discharged during the generation of the first negative exciter voltage of the next period, and the spark plug is fired, so that the ignition timing is changed from that of the capacitor C0. Not affected by charging. Therefore, when the internal combustion engine rotates at high speed, ignition is performed at a more advanced position as the rotational speed increases, and the performance of the ignition system is improved. Also, capacitor C
2 is discharged through SCRz after SCR is turned on, so there is no risk of malfunction (extinguishing) during high speed rotation.

[Brief explanation of drawings]

Fig. 1 is a circuit diagram showing an example of the ignition device already proposed, Fig. 2 is a waveform diagram showing the exciter voltage, and Figs. 3 and 4 are waveforms for explaining the operation of the ignition device shown in Fig. 1. figure,
FIG. 5 is a diagram for explaining the ignition timing of the ignition device shown in FIG. 3, FIGS. 6 to 9 are circuit diagrams showing examples of other already proposed ignition devices, and FIG. 11 and 12 are waveform diagrams for explaining the operation of the ignition device shown in FIG.
FIG. 2 is a diagram for explaining the ignition timing of the ignition device shown in FIG. In the figure, L is an exciter coil, R2 is an ignition coil, and P
is a spark plug, C0 is a discharge capacitor, C1 is a signal capacitor, C2 is a capacitor, Tr4 is a transistor, R13 and R14 are resistors, D, IS and DI6 are diodes, SCR, SCR1 and 5CR2 are thyristors. They are shown below. Patent applicant Hiroshi Mori Tomoe (2 others, patent attorney) Patent applicant: Patent attorney Hiroshi Mori (2 others)
m. $ 5 Figure 7 (2) Figure 9 Figure 10 Figure II [Z 12th [ff]

Claims (1)

[Claims] A first power source that is driven by an internal combustion engine and has a power source that intermittently generates a voltage consisting of a continuous negative first voltage, a positive voltage, and a negative second voltage, and a first capacitor that is charged by the positive voltage. a charging circuit; a first discharging circuit having a thyristor for discharging the first capacitor; and a second discharging circuit having a second capacitor charged by the positive voltage.
a third charging circuit having a charging circuit, a second discharging circuit discharging the second capacitor, a third capacitor charged by the negative first and second voltages, and a third discharging circuit discharging the third capacitor. a discharge circuit; when the negative second voltage is greater than the voltage of the third capacitor;
a first circuit for charging a capacitor and generating a trigger signal to the thyristor when the second negative voltage is less than a voltage on the third capacitor; and charging the second capacitor when the second negative voltage is generated. a second circuit that detects a voltage and prevents the thyristor from turning on while the negative second voltage is being generated; and a third circuit that discharges the second capacitor when the negative second voltage is generated; The time constant of the third capacitor and the third discharge circuit is such that the third capacitor is completely discharged when the negative second voltage is generated when the internal combustion engine is rotating at a low speed, and the third capacitor is completely discharged when the negative second voltage is generated when the internal combustion engine is rotating at a high speed. An ignition device for an internal combustion engine, characterized in that the third capacitor is selected so as not to be completely discharged when two voltages are generated.