JPS6155367A - Igniting device for internal-combustion engine - Google Patents

Abstract

PURPOSE:To prevent the occurrence of destroy due to abnormal rotation, by a method wherein, when the number of revolutions is abnormally increased, automatic delay of angle is effect by short-circuiting between the gate of a thyristor, discharging a capacitor for discharge, and a cathode. CONSTITUTION:When the number of revolutions of an engine is increased to higher than a value at which a delay of angle should be effected, during generation of a second negative exciter voltage VN2 from an exciter coil L3, a capacitor C2 is prevented from complete discharge, and the voltage is higher than the second negative voltage VN2. An SCR1 is turned ON, a Tr4 is turned ON, short- circuit occurs between the SCR and a cathode, thereby a voltage is prevented from generation. When the VN2 is increased over the voltage of a C1, a Tr4 is turned ON to charge the capacitor C1. An SCR2 is turned ON, the SCR1 is turned OFF, and during that, the SCR is prevented from turning ON. When the VN2 exceeds a peak value, the TR4 is turned OFF, and the SCR is turned ON to effect ignition. This delays an ignition timing to prevent increasing of the number of revolutions.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an ignition device for an internal combustion engine, and in particular to a capacitor which is capable of igniting at an advanced position during high-speed rotation of an internal combustion engine using a relatively N simple circuit. This invention relates to a 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, and turns on the thyristor by supplying a gate signal to the thyristor gate at the first ignition timing.

High voltage is obtained by discharging the charge accumulated in the capacitor 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, Ll is the exciter coil of the magneto-type alternator, L2 is the ignition coil, 1P is the spark plug, and R1-
R4 is a resistor, D1 to D are diodes, Co is a discharge content, CI is a signal capacitor, Trl and T
r2 is a PNP transistor, and SCR is a thyristor. The exciter coil L has three taps a, b, and c, and the voltage between taps a and b charges the capacitor C0, and the voltage between taps b and c charges the capacitor C1. It is composed of Note that tap b is grounded.

FIG. 2 shows the waveform of the exciter voltage generated by the exciter coil. This exciter voltage has a waveform consisting of a negative voltage 1, a positive voltage V following the negative voltage, and a negative voltage 8 □ following the positive voltage, which continues intermittently as shown in the figure. The amplitude of the positive voltage ■ is the negative voltage VNI,
v, larger than the amplitude of □, negative voltage VNI and ■8
The amplitudes of □ are almost equal.

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

In the ignition system shown in FIG. 1, capacitor C8 is charged by the positive exciter voltage generated between taps a and b of exciter coil L, and when thyristor SCR (hereinafter simply referred to as SCR) is turned on, capacitor C8 is charged. A high voltage is induced in the secondary circuit of 2 ignition coil L2 due to discharge, and 1
Spark plug P ignites.

On the other hand, capacitor C1 is charged by the negative exciter voltage generated between taps b and c of exciter coil L1, and discharged through resistor R1.

When the exciter voltage between Knopf b and c of the exciter coil L1 is greater than the voltage of the capacitor C1, the transistor Trl is turned on, and thereby the transistor T12
turns off. Conversely, tap b of exciter coil L1,
When the exciter voltage across c is smaller than the voltage of the capacitor CI, the transistor TrI is turned off, which turns on the transistor Tr2. transistor T,
, 2 turns on.

A gate voltage is supplied to the gate of the SCR, and if the level of this gate voltage is greater than the trigger level of the SCR, the SC
This will turn on R.

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 shows the exciter voltage and the voltages of capacitors C0 and C1 when the internal combustion engine rotates at low speed.

FIG. 3 is a waveform diagram showing the correspondence of trigger voltages to the gates of SCRs.

When the rotational speed of the internal combustion engine is low, the period of the exciter voltage becomes large. The discharge speed of capacitor C4 is determined by the time constant of capacitor C1 and resistor R3, and capacitor C5 has been completely discharged by the time a negative exciter voltage is generated between taps b and c of exciter coil L1. The above time constant shall be selected as follows.

When the first negative exciter voltage 7 is generated between taps b and c, this voltage □ is larger than the voltage of the capacitor CI, so the diode D is turned on and the transistor T
rl is turned on, and as a result of current flowing through resistor R2, transistor Tr2 is turned off. In this state, the tap C, the diode D2. A current flows through a loop between the emitter and base of the transistor Trl, the diode D1, the capacitor CI, and the tap b, and the capacitor C1 is charged. capacitor C9
teeth.

Negative exciter voltage v8. When the exciter voltage V N I exceeds the peak value, it starts discharging through the resistor R1.

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

Time when capacitor CI starts discharging 1. In other words, after the time when the peak value of negative exciter voltage ■1 occurs,
The voltage between taps b and c will be smaller than the voltage across capacitor C1. therefore.

Diode D1 turns off, which causes transistors T,
, I are turned off, and the transistor Tr,2 is turned on.

In this state, tap C, diode D2 . A current flows in the loop of transistor T 1.2 + resistor R3, Ra and tap b, and tap b is connected to the gate of the SCR.

A gate voltage G, which is a voltage between 0 and 0 divided by resistors R3 and R4, is supplied. This gate voltage G1 is 1
At time t, it increases in accordance with the subsequent negative exciter voltage VNI, so that it becomes higher than the trigger level of the SCR, thus turning on the SCR. At this point, the capacitor C6 is not yet charged, so the first spark plug P does not ignite.

Next, when a positive exciter voltage VP is generated between taps a and b of exciter coil L1, current flows through the loop of tap a, diode D3+, capacitor C01, the primary circuit of ignition coil L2, and tap b, charging capacitor Co. Ru. The capacitor C0 is charged until it is equal to the peak value of the positive exciter voltage 2.

Next, at the time when the second negative exciter voltage VNZ is generated between the taps b and c of the exciter coil L, the capacitor C1 is completely discharged as described above, and therefore the exciter voltage ■8□ is Since it is larger than the voltage of CI, the operation is exactly the same as that described for the generation of gate voltage G.

At time t2, that is, at the ordering time of the peak value of negative exciter voltage VNZ, gate voltage G2 is supplied to SCR, and SC
R is turned on. When SCR turns on.

The capacitor C0 is discharged through the SCR and the primary circuit of the ignition coil P, and a voltage is induced in the secondary circuit of the two ignition coils L2, causing the ignition plug P to ignite. In addition, in FIG. 3, the voltage of the capacitor C8 is shown by a broken line.

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

Next, the operation of the internal combustion engine during 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 SCH gate during high-speed rotation of the internal combustion engine.

When the rotational speed of the internal combustion engine is high, the exciter voltage's circumference 1υ
1 becomes smaller. As described above, the discharge rate of the capacitor C1 is determined by the time constant of the capacitor CI and the resistor R5, so the discharge rate of the capacitor C8 remains the same whether it is rotating at a low speed or at a high speed. Therefore, at high speed rotation, tap b of exciter coil L,
, c, the capacitor C1 is not completely discharged. Fourth
In the figure, the voltage across capacitor C9 is shown by a broken line.

At time t3 when the first negative exciter voltage VNI is generated between taps b and c of the exciter coil L1, the capacitor C1 is not completely discharged as described above, and therefore the voltage of the capacitor C1 is the negative exciter voltage □Bigger than. Therefore, as a result of transistor Tr+ turning off and transistor Tri turning on, the gate voltage G applied to the gate of SCR rises according to the negative exciter voltage VNI, but the voltage
When the voltage becomes higher than the voltage of Not done. Transistor Trl is on, transistor T
12 is off, the capacitor CI is charged to the peak value of the negative exciter voltage ■□. After the time t when the peak value occurs, the negative exciter voltage VNI becomes smaller than the voltage of the capacitor C3, so the transistor Trl
turns off and transistor T turns on. the result.

As explained with reference to FIG. 3, the trigger voltage G4, which is higher than the trigger level, is supplied to the gate of the SCR to turn on the SCR. However, at this point, the capacitor C0 is not charged, so the first spark plug P does not ignite.

The operation in which the capacitor C0 is charged when the positive exciter voltage {circle around (2)} is generated is the same as that described in FIG.

At time t6 when the second negative exciter voltage ■8□ is generated, the capacitor C1 is not completely discharged as described above, and therefore the voltage of the capacitor CI is larger than the negative exciter voltage ■8□, and it may be 5. The voltage of capacitor CI at time L6 is greater than the voltage of capacitor C3 at time L6 due to the relationship of the period of the exciter voltage. When the voltage of the capacitor C1 is greater than the negative exciter voltage VN2, the transistor Tri is turned off and the transistor Tr2 is turned on, so that the gate voltage G applied to the gate of the SCR rises in accordance with the negative exciter voltage VNI. Then, the time L when the SCR trigger level is exceeded
At step 7, the SCR is turned on, the capacitor C0 is discharged, and the spark plug P is ignited. Even after the SCR is turned on, the gate voltage rises according to the negative exciter voltage ■1, and at time L8 when the exciter voltage VN2 becomes larger than the voltage of the capacitor CI.

The transistor Trl is turned on and the transistor T is turned off, so that generation of the trigger voltage G5 is stopped. In this case, it is necessary to ensure a period between time t and time t8 so that one gate voltage can exceed the trigger level.

After time t8 when transistor Trl is turned on and transistor Tr2 is turned off, capacitor C1 is charged, and at time t when the peak value of the negative exciter voltage ■8□ occurs, transistor TrI is turned off and transistor TRZ is turned off. As a result of turning on, a trigger voltage G6 higher than the trigger level is supplied to the gate of the SCR, turning the SCR on, but at this point, the capacitor C0 has already been discharged, so the second spark plug P is not discharged.

As described above, during high-speed rotation of the internal combustion engine, the first ignition plug P is ignited at a time before the peak of the second negative exciter voltage, in this example, at time L7. Therefore, the ignition timing during high-speed rotation is advanced compared to the ignition timing during low-speed rotation, and automatic advance is achieved.

FIG. 5 is a diagram showing an example of the relationship between the ignition timing of one example ignition device 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 13 degrees before top dead center, but at high speeds above 3500 r, p, m, the ignition timing is 23 degrees before top dead center.

The ignition is in the advance position.

In the above ignition device, transistors Trl, 'rrz
Since a transistor for small signals can be used in the circuit, the cost can be reduced, and since a film capacitor with less variation in capacitance can be used as the single-signal capacitor C4, 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 (a coil between taps b and c) only for signal use.

Moreover, the number of turns is to lower the trigger level.

The number of turns must be the same as that of the coil for charging capacitor C9 (the coil between taps a and b).

FIG. 6 shows an ignition device in which the signal coil and the charging coil for the capacitor C6 are made common so that the same coil can be used in order to solve such a 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, Lff is an exciter coil in which a signal coil and a charging coil for capacitor C6 are used in common, R7-R7 are resistors, and D to D11 are diodes. In this circuit, the diode D in particular is used to partially shunt the signal power source so that the signal voltage does not rise too much when the internal combustion engine rotates at high speed.

In this ignition system, capacitor C6 is placed on the exciter coil 3. Diode D7. It is charged in the loop of capacitor Ca, the primary circuit of ignition coil L2, and exciter coil L3, and when SCR is on, SCR and diode D
The primary circuit of IO+ignition coil L2 is discharged in diameter. Condensing C1 is.

Above the exciter coil 3. Emitter heath of transistor Trl, diode D+, capacitor CI.

Diode D1. ．． The exciter coil is charged in loop 3 and discharged through resistor R.

Transistors Trl and Tr2 act in the same way as the ignition device shown in FIG. T1□ turns off.

Conversely, when the negative exciter voltage generated in the exciter coil L3 is smaller than the voltage of the capacitor C1, the transistor T□ is turned off, and as a result, the transistors T, 2
turns on. When the transistor T,2 is turned on, the exciter coil is turned on.3. Transistor T12. Resistor R4, diode D9. A current flows in the loop of the exciting coil L3, which applies a 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. , an exciter coil is formed with a diode D6, and 3 is partially shunted.

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 SCR trigger level 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, transistors T, 2 are connected in series to the gate of the SCR.

Performs SCR switching. therefore.

When transistor T1□ is off, transistor T
A signal voltage, that is, a negative exciter voltage is applied to rZ. Therefore, the signal voltage must be taken into account when determining the withstand voltage of the transistor Tr2.

FIG. 7 shows an ignition device in which it is necessary to consider the signal voltage with respect to the withstand voltage of five transistors, and in which case the number of transistors can be reduced to one. In the figure, elements corresponding to those of the ignition system shown in FIG. 6 are designated by the same reference numerals. In the figure.

Tr3 is an NPN transistor, R8 and R7 are resistors, and D1□ is a diode. In this circuit, the transistor Tr3 is provided in parallel to the gate of the SCR.

In this ignition system, capacitor C0 is connected to exciter coil L3r diode D9. Capacitor C01 is charged in the primary circuit of ignition coil L2 and the loop of exciter coil L3, and when SCR is on, SCR and diode D
It is discharged through the primary circuit of the 1°1 ignition coil L2. Capacitor C1 is.

Exciter coil L3. Capacitor C8, diode D
+z, base-emitter of transistor Tr, 3;

Diode D1. It is charged in the loop of exciter coil L3 and discharged through resistor R3.

When the negative exciter voltage generated in the exciter coil L is larger than the voltage of the capacitor CI, the diode D1□ is turned on, so the transistor 'rr:+ is turned on, and conversely, the negative exciter voltage generated in the exciter coil L is turned on. When the voltage is lower than the voltage of the capacitor CI, the diode D1□ is turned off, and therefore the transistor Tr3 is turned off.

When transistor Tr3 turns off, exciter coil L
1, resistor R8, resistor Rq, diode D9, and the exciter coil 3. A current flows through the loop 3, and a gate voltage is supplied to the gate of the SCR, turning the SCR on.

As is clear from the above basic operations, the operations performed in this ignition device when the internal combustion engine rotates at low speeds and at high speeds are the same as those 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 T in parallel with the gate of the SCR, so that even when the transistor T is off, the transistor is connected to the voltage drop ( (for example, 0.6 V or less), there is no need to consider the withstand voltage of the transistor. Also, the transistor is 1
Since only one piece is required, it is possible to reduce costs. moreover.

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
0 is charged and the SCR is off, the voltage loop of the capacitor C, SCR, the primary circuit of the diode DIO1 ignition coil L2, and the capacitor C6,
Capacitor C,, SCR anode gate gate series resistance Ra + primary circuit of ignition coil L2, capacitor C8
A voltage loop of 1. These voltage loops cause the SCR to have a gate series resistance R to the voltage of the capacitor C0.
A forward voltage which is the sum of the voltage of Il is applied. Therefore, an SCR with high forward breakdown voltage is required.

FIG. 8 shows an ignition device that can lower the normal pressure resistance of the SCR. 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, +Tr4 is a PNP l-run lister, R8° and R1+ are resistors, and D13 and DI4 are diodes.

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

In this ignition system, capacitor C0 is placed on the exciter coil 3. Diode D? , the primary circuit of capacitor CG + ignition coil L2, exciter coil, and is charged in the loop, and when SCR is on, SCR, diode D
It is discharged through the primary circuit of IO1 ignition coil L2. Capacitor C7 is.

Exhaust → no "Ita coil L3. Emitter/base of transistor Tr4, diode D14. Capacitor CI.

It is charged in the loop of exciter coil L3 and discharged through resistor R1.

When the negative exciter voltage generated across the exciter coil 3 is greater than the voltage across the capacitor C1, the diode DI4 is turned on and therefore the transistors T, 4 are turned on. Conversely, when the negative exciter voltage generated in the exciter coil L3 is smaller than the voltage of the capacitor CI, the diode DI4 is turned off, and therefore the transistor Tr4 is turned off. When transistors T, . . . 4 are turned off, exciter coils L . . A current flows in the loop of the resistor RI I + resistor RIG+ exciter coil L3, 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 this ignition device, when turning on the SCR.

Above the exciter coil 3. °Resistance RI 1 + resistance. ,
The loop current of the exciter coil L2 flows and a gate voltage is supplied to the gate of the SCR, but when the SCR is turned on, the capacitor C0 is discharged.

SCR, diode D,. A discharge current flows through the primary circuit of the first ignition coil L2. This discharge current is.

As a result of the current flowing in the opposite direction to the current supplying the gate voltage to the SCR, the gate of the SCR becomes 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 in 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, R+□ is a resistance I Dis is a diode.

In this circuit, the current for supplying the gate voltage to the SCR is the exciter coil L! , resistance R11 + resistance RI2
, flows in the loop of exciter coil L3. The discharge current of the capacitor C0 flows through the SCR and the primary circuit of the ignition coil L2, but it does not cancel out the above current for supplying the gate voltage, so the gate of SCH is not reverse biased, and therefore the I/Riga rotation is There is no problem of the number going up.

In this ignition system, capacitor C0 is an exciter coil.3. Diode D? , capacitor C69, primary circuit of ignition coil L2, diode D12. It is charged in the loop of exciter coil L3.

When the SCR is on, it is discharged through the primary circuit of the SCR and ignition coil L2. Capacitor C1 is.

Exciter coil 1. Emitter/base of transistor Tr4, diode D14. The capacitor C1 is an exciter coil, is charged in the loop, and discharged through the resistor R.

When the negative exciter voltage generated across the exciter coil is greater than the voltage across capacitor C1, diode DI4 is turned on and thus transistors T, 4 are turned on. Conversely, when the negative exciter voltage generated across the exciter coil □ is smaller than the voltage of the capacitor C1, the diode D'+4 is turned off, and therefore the transistors T, , 4 are turned off. When transistor Tr4 turns off, exciter coil Lj, iW anti-R+ + +
A current flows in the loop of resistor R1□ and exciter coil L3, gate voltage is supplied to the gate of SCR, and SC
Turn on R.

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 device described above, even if the rotational speed of the internal combustion engine increases significantly, it is ignited at the advance position, so it is not possible to suppress the increase in rotational speed. may be destroyed.

[Object and structure of the invention]

An object of the present invention is to retard the ignition timing by one point when the internal combustion engine reaches a certain rotation speed or higher. That is, an object of the present invention is to provide an ignition device that reduces the torque of the internal combustion engine each time it is delayed so that the rotational speed of the internal combustion engine does not rise above a certain rotational speed.

The ignition device for an internal combustion engine of the present invention includes a power source that is driven by the internal combustion engine and that intermittently generates a voltage consisting of a continuous negative first voltage, a positive voltage, and a negative second voltage, and a power source that is charged by the positive voltage. a first charging circuit having a first capacitor, a first discharging circuit having a thyristor for discharging the first capacitor, and a second capacitor having a second capacitor charged by the first and second voltages. 2 charging circuit, and a second discharging circuit that discharges the second capacitor;
a third charging circuit having a third capacitor charged by the first and second voltages; and a third discharging circuit discharging the third capacitor.

charging the second capacitor when the second voltage of the quality is greater than the voltage of the second capacitor;

a first for generating a trigger signal to the thyristor when the second voltage of the quality is less than the voltage of the second capacitor;
and a second circuit for inhibiting the on-operation of the thyristor when the second voltage of the quality is smaller than the voltage of the third capacitor, and the time constant of the second capacitor and the second discharge circuit.

When the internal combustion engine rotates at a low speed and the second voltage of this quality is generated, the second capacitor is completely discharged.

The second capacitor is selected so as not to be completely discharged when the second voltage of the quality is generated during high-speed rotation of the internal combustion engine, and the time constant of the third capacitor and the third discharge circuit is set to the internal combustion engine. The third capacitor is completely discharged when the second voltage of the quality is generated when the engine is rotating at a normal speed, and the third capacitor is completely discharged when the second voltage of the quality is generated when the engine is rotating at a high speed of an abnormal speed. It is characterized by being selected so that it does not occur.

In addition, especially when a magneto-type generator has two magnets each having an N pole and an S pole, the two generated exciter voltages are a first positive voltage and a first negative voltage following this positive voltage. The voltage has an intermittently continuous waveform consisting of a voltage, a second positive voltage following this negative voltage, and a second negative voltage following this positive voltage.

When the exciter voltage is such a voltage, the ignition device of the present invention is driven by an internal combustion engine.

a power source that intermittently generates a voltage consisting of a continuous positive first voltage, a negative first voltage, a positive second voltage, and a negative second voltage; and a first capacitor that is charged by the positive second voltage. a first charging circuit having a thyristor for discharging the first capacitor; a second charging circuit having a second capacitor charged by the first voltage of the quality; 1) η a second discharge circuit that discharges the second capacitor; and a fourth discharge circuit that is charged by the positive first voltage.
a fourth charging circuit having a capacitor; a fourth discharging circuit discharging the fourth capacitor; charging the second capacitor when the second voltage of the quality is greater than the voltage of the second capacitor; a circuit for generating a trigger signal to the thyristor when a second voltage is less than the voltage of the second capacitor and while the fourth capacitor is discharging.

a third circuit that detects this discharge current and prohibits the on-operation of the thyristor; The second capacitor is selected so that it is completely discharged when the first voltage of the quality is generated when the internal combustion engine rotates at high speed, and the second capacitor is selected so that the second capacitor is not completely discharged when the first voltage of the quality is generated when the internal combustion engine rotates at high speed. The time constant with the fourth discharge circuit is such that when the first voltage of the quality is generated when the internal combustion engine is rotating at a normal speed, the fourth capacitor is completely discharged, and when the internal combustion engine is rotating at a high speed of an abnormal speed, the fourth capacitor is completely discharged. The present invention is characterized in that the fourth capacitor is selected to be completely discharged before the peak value of the voltage occurs.

〔Example〕

The present invention will be described in detail below with reference to one drawing.

FIG. 10 is a circuit diagram showing one embodiment of the present invention. This embodiment is applied to the ignition device shown in FIG.

A retardation circuit is added. therefore.

Elements corresponding to those in FIG. 9 are designated by the same reference numerals. In the figure, +RI3 to R17 are resistors, D16 to D2
゜ is a diode, C2 and C3 are capacitors, TrS
is the NPN) run risk, and 5CRI is the thyristor.

11 and 12 show the exciter voltage of the exciter coil L and the capacitor C8 when the internal combustion engine rotates at a normal speed and when the internal combustion engine rotates at a speed that should be retarded. , CI and C2, and a waveform diagram showing the correspondence relationship between the voltages of CI and C2 and the trigger voltage to the gate of the SCR. Although the period of the exciter voltage during high-speed rotation in FIG. 12 is smaller than the period of the exciter voltage during high-speed rotation in FIG. 11, the same period is shown for clarity in one drawing.

The first negative exciter voltage VN is applied to the exciter coil L3.
I is generated, and the exciter voltage V N l is applied to the capacitor C
When the voltage is greater than 9, the voltage on the exciter coil 3. Emitter-base 2 diode D of transistor Tr4
I 4 + capacitor CI, diode DI9+
A current flows through the loop of D20+ exciter coil 3, and capacitor C8 is charged. The charged capacitor CI is discharged through the resistor R, and the discharge rate is determined by the time constant of the capacitor CI and the resistor R1.

Similarly, when the exciter voltage ■HI becomes larger than the voltage of the capacitor C2, the exciter coil L3゜capacitor C2, diode D+a, I・run risk T''rs
A current flows through the loop between the emitter base and the exciter coil L3, and the capacitor C2 is charged. The charged capacitor C2 is discharged through the resistor RIS, and the discharge rate is determined by the time constant of the capacitor C2 and the resistor RIS.

The time constant of capacitor CI and resistor R3 is
The capacitor CI is selected to be larger than the time constant of the resistor 2 and the resistor RIS, and the capacitor C2 is not completely discharged when the second negative exciter voltage occurs during normal high speed rotation. When the engine seems to be completely discharged and the rotation speed is higher than the one that should be retarded,
The above time constant is selected such that capacitor C2 is not completely discharged.

Note that the first negative exciter voltage ■8. While this is occurring, a gate voltage is generated as shown in FIG. 4, but since capacitor C0 is not yet charged, ignition does not occur.

When a positive exciter voltage ■2 is generated in the exciter coil L3, the exciter coil L3+diode D1. Capacitor CO + primary circuit of ignition coil L2, resistor Rl
l + current flows in the loop of exciter coil L3,
Capacitor C8 is charged.

When the internal combustion engine is at high rotational speed at normal speed.

As shown in FIG. 11, when the second negative exciter voltage vN□ is generated in the exciter coil L3, the generation time t,
Then, the voltage of the 8 capacitor C1 is the negative exciter voltage V,
Since it is larger than 4□, diode D turns off, which turns off transistor T+,4. When transistor Tr4 is turned off, exciter coil L3. Resistance R
11, diode D, 6. Resistor R13, transistor T
As a result of current flowing through the F S + exciter coil loop 3, a gate voltage GI is supplied to the gate of the SCR, and at time t2, the SCR is turned on, the capacitor C0 is discharged, and one ignition is performed.

After the time when the peak of the second negative exciter voltage V□ occurs, the voltage of the capacitor C0 again becomes larger than the negative exciter voltage □, 41, so the gate voltage G2 is supplied to the gate of the SCR. . However, since capacitor C0 has already been discharged, ignition does not occur with this gate voltage G2.

When the rotational speed of the internal combustion engine exceeds the rotational speed that should be retarded, the second negative exciter voltage ■8□ is applied as shown in FIG.
When this occurs, the capacitor C2 is not completely discharged, and at the second time L4, the voltage of the capacitor C2 becomes higher than the second negative exciter voltage VN2. Therefore, at time t, the diode 018 is turned off, which turns off the transistor T gate. When the transistor T0 is turned off, current flows through the 5 exciter coils t, z, Ff anti-RI+, diode DI61 resistor R11, resistor Rl 4 + exciter filter L3, and as a result, gate voltage is supplied to the gate of SCR, and SCR is turned on. . SCR
.

When turned on, exciter coil L3. transistor T
As a result of current flowing through the emitter-base of r4, resistor R+a, 5CR1, and exciter coil L, transistor Tr4 is turned on. When the transistor T r a is turned on, the gate and cathode of the SCR are short-circuited, so that the gate voltage G1 explained in FIG. 11 is not generated.

At time t, when the second negative exciter voltage becomes greater than the voltage on capacitor C3, diode Dz turns on, which turns on transistor T□, which turns the exciter coil 1. Emitter/base of transistor Tr4, diode D14. Capacitor CI, diode DI9
．． Dzo+ Current flows in the loop of exciter coil L3, charging capacitor C1, and 5CRz
A gate voltage is supplied to the gate of 5CR2, and 5CR2 is turned on. When 5CR2 is turned on, 5CR1 is reverse biased by the voltage of capacitor C3, and SCR is turned off.

Therefore, the SCR is in an on state from time t4 to time t, and during this period, the SCR is suppressed from being turned on.

When the second negative exciter voltage exceeds the peak value at time t, the time constant of one circuit C, R is larger than the time constant of circuit C2RIs, so at time t, and a little later time t, transistor Tr is activated. , transistor T,4 is turned off before , gate voltage G3 is supplied to the gate of SCR, and SC
R is turned on and ignition is performed. Subsequently, one time later, when the transistor Tr5 is turned off, a gate voltage is supplied to the gate of the SCR, and the SCR is turned on. When SCR, turns on, transistors T, , 4 turn on, shorting between the gate and cathode of SCR, and increasing the gate voltage G3.
supply will be stopped.

When the internal combustion engine reaches a rotational speed at which it should be retarded due to the above-described operation, ignition is performed at a position slightly past the peak value of the second negative exciter voltage VN□. Since the ignition timing is delayed in this way, the torque of the internal combustion engine is reduced and the increase in rotational speed is suppressed.

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

For example, when the rotation speed is 350 Or, p, m, or lower, Q at the time of ignition is 13 degrees before top dead center, but the rotation speed is 350 Or.
.

When the engine rotates at normal speeds such as p, m, or higher, the ignition timing is 23 degrees before top dead center, and the ignition is ignited at an advanced position. When the internal combustion engine reaches a rotational speed of 950 Or, p, m, which should be retarded, it is ignited at 7 degrees before top dead center.

FIG. 14 is a circuit diagram showing an embodiment of the present invention. In this embodiment, the magneto-2 generator has two 6f1 stones consisting of an N pole and an S pole.

As shown in FIG. 15, a first positive voltage vP is applied to the exciter coil, and a first negative voltage VNI following this positive voltage is applied to the exciter coil.
A second positive voltage VFZ follows this negative voltage.

A second wave occurs due to the reaction of this positive voltage and follows this positive voltage.
This circuit is capable of automatic retardation when a waveform consisting of a negative voltage VN□ is intermittently generated.

Similar to the embodiment shown in FIG. 10, this embodiment is obtained by adding a retard circuit to the ignition system shown in FIG. 9. Therefore, elements corresponding to those in FIG. 9 are designated by the same reference numerals. In fig.

L4 is an exciter coil +R1+B and R19 is a resistor.

021 and D2□ are diodes, and Ca is a capacitor.

T r b is an NPN transistor. Exciter coil L4 has three taps g, h, and i.

Tap g when a positive exciter voltage occurs.

The configuration is such that capacitor C0 is charged by the voltage between taps 1 and capacitor C4 is charged by the voltage between taps h and i, and capacitor CI is charged by the voltage between taps g and i when a negative exciter voltage is generated. has been done.

16 and 17 show the exciter voltage of the exciter coil L4, the capacitor Co, FIG. 4 is a waveform diagram showing the correspondence between the voltages of C+ and C4 and the trigger voltage to the gate of the SCR. Although the period of the exciter voltage during high-speed rotation in FIG. 17 is smaller than the period of the exciter voltage during high-speed rotation in FIG. 16, the same period is shown for clarity of one drawing.

When a first positive exciter voltage VPI is generated between taps h and i of exciter coil L4, tap h and diode D25 . Capacitor C1, diode D31. A loop current of tap i flows and capacitor C4 is charged to the peak value of exciter voltage V p 1. Capacitor C
4 is a resistor R2 after charging.

Discharge via the emitter-base of transistors T, , 6. Therefore, while capacitor C4 is discharging,
Since the transistor T r b is turned on and the gate and cathode of the SCR are shorted, the SCR is not turned on.

When the internal combustion engine is rotating at normal speed, the first
As shown in Figure 6, capacitor C4 is.

The first positive exciter voltage VP1 is discharged along the falling curve, and the first negative exciter voltage 81 is at time 1. Now, assume that the time constants of capacitor C4 and resistor R1 are determined so that capacitor C4 is completely discharged.

When the internal combustion engine is at high rotational speed at normal speed.

As shown in FIG. 16, when the first negative exciter voltage VN1 is generated in the exciter coil L4, 1 generation time 1.
Then, the voltage on capacitor C+ is the negative exciter voltage V
Since it is larger than NI, the diode D is turned off, thereby turning off the transistor Tr4. Transistor Tr
4 is turned off, 1 tap i of exciter coil L4,
As a result of current flowing in the loop of tap g consisting of resistor RI + + diode 016, resistor R18, and exciter coil L, gate voltage G1 is supplied to the gate of ScR, and at time t, SCR is turned on and capacitor C0 is turned on. Discharge 5
Ignition takes place.

After time t3 when the peak of the first negative exciter voltage vN occurs, the voltage of the capacitor C5 again becomes larger than the negative exciter voltage VNI, so that the gate voltage G2 is supplied to the gate of the SCR. However, since capacitor C0 has already been discharged, ignition does not occur with this gate voltage G2.

A second positive exciter voltage VP is applied to the exciter coil L4.
When Z occurs, the primary circuit of tap g, diode D7, capacitor C01 ignition coil L2.

Diode D15. Current flows in the loop of tap i and charges capacitor C0.

A second negative exciter voltage V is applied to the exciter coil L4.
8□ occurs, the capacitor C is lower than this voltage VN□.
Since the voltage at I is large, a gate voltage to the SCR is generated, but as mentioned above, the voltage ■8□ is generated by the reaction of the voltage V F 2 and has a small amplitude, so the SC
A gate voltage exceeding the trigger level of R is not generated. Therefore, no ignition occurs during generation of the second negative exciter voltage VH2.

When the rotational speed of the internal combustion engine exceeds the rotational speed to be retarded, the period of the exciter voltage becomes shorter, so as shown in FIG. 17, the time t4 at which the first negative exciter voltage Vold occurs
In this case, capacitor C4 is not completely discharged and becomes completely discharged before time t, when the peak of exciter voltage V, 41 occurs. As described above, while the capacitor C4 is discharging, the gate and cathode of the SCR are short-circuited, so in this case, the gate voltage G as explained in FIG. 16 is not generated. Capacitor C4 has been discharged before time t, so at time 1 [, transistor Tr6 is off and 1
Therefore, at time t, gate voltage G3 is generated, SCR is turned on by this gate voltage G3, and capacitor C
6 is discharged and 2 ignition is performed.

As a result of the above-described operation, when the internal combustion engine reaches the speed that should be retarded or higher, ignition is performed at the time when the peak value of the first negative exciter voltage VH1 occurs, so the second ignition timing is delayed. . This reduces the torque of the internal combustion engine and suppresses the increase in the number of rotations.

〔effect〕

According to the present invention, it is possible to automatically advance the angle with a simple circuit configuration, and when the rotational speed of the internal combustion engine increases abnormally, a short circuit is established between the gate and cathode of the thyristor that discharges the discharge capacitor. By doing so, the SCR is prevented from being turned on during this period, and the thyristor is turned on after the predetermined period has elapsed, so that automatic retardation can also be performed. Therefore, when the rotational speed of the internal combustion engine abnormally increases, the ignition timing is delayed by the automatic retard, thereby reducing the torque and making it possible to prevent damage caused by abnormal rotation of the internal combustion engine.

[Brief explanation of drawings]

FIG. 1 is a circuit diagram showing an example of a previously proposed ignition device. Figure 2 is a waveform diagram showing the exciter voltage, Figures 3 and 4 are waveform diagrams for explaining the operation of the ignition system shown in Figure 1, and Figure 5 is the ignition timing of the ignition system shown in Figure 3. FIGS. 6 to 9 are circuit diagrams showing examples of other previously proposed ignition devices, and FIG. 10 is a circuit diagram showing an embodiment of the present invention. 11 and 12 are waveform diagrams for explaining the operation of the ignition device shown in FIG. 10, FIG. 13 is a diagram for explaining the ignition timing of the ignition device shown in FIG. 10, and FIG. 14 is a diagram for explaining the ignition timing of the ignition device shown in FIG. FIG. 1 is a circuit diagram showing an embodiment of the present invention. FIG. 15 is a waveform diagram showing the exciter voltage, and FIGS. 16 and 17 are waveform diagrams for explaining the operation of the ignition device shown in FIG. 14. In the figure, L and R4 are exa-ita coils, R2 is an ignition coil, P is a spark plug, C0 is a discharge capacitor,
C1 is a signal capacitor + CZ + C3 and C4 are capacitors + Tr41 ``rrs and Tr6 are transistors, R14 and RI5 are resistors, D, 7 and [) +
The aba diode, SCR and SCR+ indicate a thyristor, respectively. L) 2 Figure 1 Figure 2 Figure 311211 Figure 4 Figure 5 Figure 6 (21 Figure 7 Figure 8 (2) Figure 10 Figure 12 Figure 3500 q'vOOOai'd
Father r, P-1n. 13 [D Figure 15

Claims (2)

[Claims] (1) A power source that is driven by an internal combustion engine and 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 first charging circuit having a thyristor for discharging the first capacitor; a second charging circuit having a second capacitor charged by the negative first and second voltages; a second discharge circuit for discharging the second capacitor; and a second discharge circuit for discharging the second capacitor;
a third charging circuit having a third capacitor charged by a voltage; a third discharging circuit discharging the third capacitor; and a third discharging circuit discharging the third capacitor; a first circuit that charges the thyristor and generates a trigger signal to the thyristor when the negative second voltage is less than the voltage of the second capacitor;
a second circuit that prohibits the thyristor from turning on when the negative second voltage is lower than the voltage of the third capacitor, and the time constant of the second capacitor and the second discharge circuit is set to The second capacitor is selected such that when the negative second voltage occurs during low speed rotation, the second capacitor is completely discharged, and when the negative second voltage occurs during high speed rotation of the internal combustion engine, the second capacitor is not completely discharged. death,
Further, the time constant of the third capacitor and the third discharge circuit is such that when the negative second voltage is generated during normal high-speed rotation of the internal combustion engine, the third capacitor is completely discharged, and the third capacitor is completely discharged when the internal combustion engine is rotating at a normal 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 the negative second voltage is generated during high speed rotation. (2) a power source that is driven by an internal combustion engine and that intermittently generates a voltage consisting of a continuous positive first voltage, a negative first voltage, a positive second voltage, and a negative second voltage; a first charging circuit having a first capacitor charged by two voltages; a first discharging circuit having a thyristor for discharging the first capacitor; and a second capacitor charged by the negative first voltage. a second charging circuit, a second discharging circuit that discharges the second capacitor, a fourth charging circuit that includes a fourth capacitor that is charged by the positive first voltage, and a fourth discharging circuit that discharges the fourth capacitor. a circuit that causes the second capacitor to charge when the negative second voltage is greater than the voltage on the second capacitor; and a trigger signal to the thyristor when the negative second voltage is less than the voltage on the second capacitor; and a third circuit that detects this discharge current and prohibits the on-operation of the thyristor while the fourth capacitor is discharging. The time constant is set such that the second capacitor is completely discharged when the negative first voltage is generated when the internal combustion engine rotates at a low speed, and the second capacitor is completely discharged when the negative first voltage is generated when the internal combustion engine is rotated at a high speed. be selected so that it does not discharge completely.
Further, the time constant of the fourth capacitor and the fourth discharge circuit is such that when the negative first voltage is generated during normal high-speed rotation of the internal combustion engine, the fourth capacitor is completely discharged, and the fourth capacitor is completely discharged when the internal combustion engine is rotating at a normal speed. An ignition system for an internal combustion engine, characterized in that the fourth capacitor is selected to be completely discharged before the peak value of the first negative voltage occurs during high-speed rotation.