JPS6338545B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a non-contact ignition device, and in particular, to a non-contact ignition device, and in particular to an ignition signal that short-circuits the spark plug electrodes of each cylinder, and a method that prevents the discharge loop of the spark plug due to the short circuit between the electrodes. The present invention relates to a non-contact ignition device for an internal combustion engine that includes an auxiliary ignition section that generates a sustained auxiliary ignition signal.

[Background of the invention]

Conventionally, a DC/DC converter is used as an auxiliary ignition section that generates an auxiliary ignition signal. For example, when generating an auxiliary ignition signal using a DC/DC converter in Japanese Patent Application No. 58-39002, Japanese Patent Application No. 58-76164, etc., the duration of the discharge loop of the ignition plug due to a short circuit between the electrodes is set to a certain period of time. A control method was used. However, since the facing time between the distributor rotor and the side plug decreases as the speed increases, controlling the discharge loop duration to a constant value will cause
An auxiliary ignition signal is generated even when the rotor and side plug are not facing each other, causing spark outage. At this time, the DC/DC converter was in an unloaded state, causing a problem in which pre-ignition occurred on the next ignition.

Therefore, a method has been proposed in which the duration of the discharge loop is decreased as the engine speed increases. For example, this method is adopted.
The device shown in FIG. 1 has been proposed. However, the device shown in FIG. 1 has the disadvantage that the operating time of the DC/DC converter in the constant rotation range from the time of startup is longer than necessary, resulting in increased energy loss. Furthermore, the operation of the DC/DC converter became unstable in the high rotational speed range of the engine, making it necessary to stop the DC/DC converter at a certain appropriate rotational speed. The conventional device will be explained below with reference to FIGS. 1 to 3.

In FIG. 1, power from a battery 1 is supplied to various parts of an ignition device 3 via a key switch 2. As shown in FIG. The ignition device 3 is composed of a pickup coil 3a for detecting the engine, a control circuit for controlling the detection output of the pickup coil 3a, and a power transistor 3b operated by an output signal of the control circuit. 4 is an ignition coil, 5 is a rotor 5a,
A power distributor having a side plug 5b and ignition plugs 6 to 9 are installed in each cylinder.

A DC/DC converter is composed of resistors 17 to 24, Zener diodes 31, capacitors 33 and 34, comparator 36, transistors 37 and 38, diodes 29 and 30, and step-up transformer 39. Resistors 10 to 16 and 40 and diode 2
5 to 27, a comparator 35, and a capacitor 32 constitute a one-shot multi-circuit that determines the operating time of the DC/DC converter.

In addition, the ignition device 3 receives an AC signal (signal in Fig. 2a) synchronized with the engine via a pickup coil 3a.
Vp), and the control circuit controls the ON time of the power transistor 3b. When the power transistor 3b turns on, the primary current _I1 shown in FIG. , a negative secondary voltage V ₂ is generated on the secondary side of the ignition coil 4 as shown in FIG. 2c. This voltage is applied to the spark plugs 6 to 9 via the rotor 5a and side plug 5b of the power distributor 5,
The insulation between the electrodes of the spark plugs 6 to 9 is destroyed. Normally, in order to break the insulation between the electrodes of the spark plugs 6 to 9, it is necessary to apply a high voltage of -10 kV to -20 kV to these electrodes.

When the insulation between the electrodes of the spark plug 6 is broken,
GND → Spark plug → Side plug 5b in power distributor 5
→ Rotor 5a → Secondary coil of ignition coil 4 →
A discharge loop is formed along the route from the capacitor 34 of the DC/DC converter to GND, and a secondary current I ₂ flows as shown by the solid line in FIG. 2d.

Note that the discharge duration (second
t1) shown in c and d of the figure is approximately 1 msec, and the second
The discharge ends at point A in Figure c. Further, the peak value of the discharge current _I2 shown in FIG. 2d (not including the capacitive discharge) is 40 to 50 mA.

As shown in FIG. 2c, when the insulation between the spark plug electrodes is broken, the voltage required to continue discharging the spark plugs 6 to 9 is about -2 kV. Therefore,
If medium-high voltage of about -2kV generated by the DC/DC converter is superimposed on the secondary side of the ignition coil 4 after insulation breakdown between the electrodes of the spark plugs 6 to 9, the discharge in the spark plugs 6 to 9 will continue. becomes possible. Therefore,
By superimposing the output voltages of the DC/DC converter from startup to high speed, with appropriate timing control and operating time control, this will lead to improved engine fuel efficiency and efficiency.

Next, we will explain the DC/DC converter. The power supply line of the comparator 36 is stabilized by the resistor 22 and the Zener diode 31. Diode 29 is for protection of power transistor 38.

An oscillator is configured by the resistors 17 to 21, a capacitor 33, and a comparator 36, and the output signal of the oscillator is sent to the transistor 37 via the resistor 33.
Since it is applied to the base of transistor 3
7 switching is repeated. transistor 3
7, a base current flows to the power transistor 38 via the resistor 24, the power transistor 38 is turned on, and current flows to the primary coil of the step-up transformer 39. The step-up transformer 39 is configured in a forward type, and the power transistor 3
When 8 is turned on, a medium-high voltage is generated in the step-up transformer 39, and the voltage is changed from GND to capacitor 34 to diode 3.
0→The capacitor 34 is charged through the route of the secondary coil of the step-up transformer 39. The transistor 37
When turned on, the power transistor 38 turns off,
The flyback voltage generated at this time is blocked by diode 30. Due to the switching operation of the power transistor 38, the voltage at the connection point between the capacitor 34 and the anode side of the diode 30 becomes -
It will be about 2kV.

As described above, in the ignition device 3, the ignition plugs 6 to
When the insulation between electrodes 9 is broken, GND→spark plug→side plug 5b of power distributor 5→rotor 5a→
Secondary coil of ignition coil 4 → Capacitor 34 →
A discharge loop is formed at the GND route, and a discharge current _I2 flows. On the other hand, since the capacitor 34 is charged to about -2kV while the oscillator is operating, the discharge current of the capacitor 34 is equal to the discharge current I ₂
The discharge current of the spark plugs 6 to 9, seen as a whole, continues up to point B where the oscillator stops operating, as shown by the broken line in FIG. 2d, and the secondary voltage V ₂ shown in FIG. will continue until point B.

Resistance 10-16, 40, diode 25-2
7, a comparator 35, and a capacitor 32 constitute a one-shot multi-circuit. Collector voltage of power transistor 3b of ignition device 3
_V1 has the waveform shown in FIG. 2e, and the flyback voltage generated when the power transistor 3b is turned off is divided by the resistor 10 and the resistor 40, and applied to the non-inverting terminal of the comparator 35 via the diode 25. Serves as a one-shot multi trigger signal. That is, when the non-inverting terminal voltage of the comparator 35 is higher than the inverting terminal voltage in synchronization with the OFF operation of the power transistor 3b of the ignition device 3, the output terminal of the comparator 35 becomes high level and the diode 28 becomes non-conductive. At this time, since the capacitor 33 of the oscillator is repeatedly charged and discharged, the DC/DC converter operates, and the capacitor 34 is charged.

When the output terminal of the comparator 35 becomes low level, the voltage at the inverting terminal of the comparator 36 becomes approximately 0.7V corresponding to the forward drop of the diode 28, and since the non-inverting terminal voltage is higher, the voltage at the inverting terminal of the comparator 36 becomes approximately 0.7V.
The output is always high level. Therefore, transistor 37 turns on, and power transistor 38 turns on.
Since it is turned off, the DC/DC converter stops operating. The output terminal voltage waveform of the comparator 35 is
FIG. 2g shows the collector voltage waveform of the transistor 37 in FIG. Figures 3h and 3 show the ignition device 3.
Collector voltage waveform of power transistor 3b
Indicates V ₁ . The h diagram is at low speed, and the l diagram is at high speed.
Further, the resistor 16 has a high resistance of about 3MΩ.

Next, the effect at low speeds will be explained.

When the collector voltage V ₁ of the power transistor 3b is applied to the resistor 10, the non-inverting terminal of the comparator 35 has a voltage i as shown in FIG. 3 due to the flyback voltage.
A signal with a trigger waveform as shown in is applied. Since the peak voltage value of this trigger signal is larger than the non-inverting terminal voltage of the comparator 35 (divided voltage of the resistors 12 and 13), the output voltage of the comparator 36 becomes high level, and the capacitor 32
Via resistor 15, diode 27, and resistor 16,
It is charged according to a time constant determined by the resistors 15, 14, and 11 and the capacitor 32. Resistor 16 is about 3M
Since it has a high resistance of Ω, it hardly participates in charging the capacitor 32. This charging current causes resistance 11
The output of the comparator 36 remains at a high level while the voltage V ₅ generated at the inverting terminal voltage V ₄ is greater than the inverting terminal voltage V 4 (V ₅ >V ₄ ). Note that the waveforms of voltages V ₅ and V ₄ are shown in FIG. 3k.

When the voltage V ₅ <V ₄ , the output terminal of the comparator 36 becomes low level, and the current flows through the resistor 15 and the capacitor 3 flows through the resistor 16.
2 and the current flowing through the diode 28 from the inverting terminal of the comparator 36 of the oscillator. The charge in the capacitor 32 is discharged with a time constant determined by the capacitor 32 and the resistor 16, but at constant speed, the ignition interval is longer than the discharge time, so the contact voltage V ₃ between the capacitor 32 and the cathode of the diode 27 is It drops to 0V as shown in Figure j.

However, in the high speed range, the ignition interval becomes short and the contact voltage _V3 never drops to 0V as shown in FIG. 3n, and the capacitor 32 is always charged.

When the trigger signal shown in FIG. 3m is applied in this state, the capacitor 32 is not completely discharged, so the peak value of the voltage _V5 decreases compared to when the speed is low. Therefore, at high speeds, V ₅ > V ₄ than at low speeds.
The time it takes is shortened. That is, the waveforms of voltages V ₅ and V ₄ are as shown in FIG. 3o.

The time when V ₅ >V ₄ in FIG. 3k and o is the one-shot time, the output terminal of the comparator 35 becomes high level, and the power transistor 38 is driven by the oscillator, so that the DC/DC converter operates.

The speed characteristics due to the operation of the DC/DC converter of the apparatus shown in FIG. 1 constructed as described above are shown by the two-dot chain line in FIG.

From FIG. 4, it can be seen that in the case of the device shown in FIG. 1, the operating time of the DC/DC converter becomes longer than necessary in the low speed rotation range of the engine from the time of startup, resulting in an increase in energy loss. Furthermore, when the peak value of the non-inverting terminal voltage V ₅ of the comparator 35 becomes near the inverting terminal voltage V ₄ , the operation of the comparator 35 becomes unstable, and there is a region in which overlapping discharges occur and do not occur repeatedly. Therefore, in conventional devices, it was necessary to stop the operation of the DC/DC converter at a certain appropriate rotation speed.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned conventional problems, and its purpose is to provide a non-contact point for internal combustion engines that can distribute and supply an efficient and stable ignition signal to each cylinder according to the rotation of the engine. The purpose is to provide an ignition device.

[Summary of the invention]

In order to achieve the above object, the present invention provides an ignition section that sequentially supplies an ignition signal synchronized with engine rotation between the spark plug electrodes of each cylinder to short-circuit between the electrodes of each spark plug, and a short-circuit between the electrodes. an auxiliary ignition unit that supplies an auxiliary ignition signal to the ignition unit to sustain a discharge loop of the ignition plug, and a pulse signal that generates a differential pulse signal in synchronization with engine rotation. A generator circuit, a rotation speed-voltage conversion circuit that generates a signal at a level corresponding to the engine rotation, and a reference level are compared with the level of the differential pulse signal, and when the level of the differential pulse signal exceeds the reference level, an auxiliary signal is generated. The auxiliary ignition section is composed of an auxiliary ignition signal generation circuit that generates an ignition signal, and the rotation speed -
The output signal of the voltage conversion circuit is superimposed on the reference level of the auxiliary ignition signal generation circuit, the duration of the discharge loop in the engine's low rotation range is maintained at a constant time, and the duration of the discharge loop in the engine's high rotation range is maintained at a constant time. It is characterized in that the number of rotations is gradually decreased as the number of rotations increases.

[Embodiments of the invention]

Hereinafter, preferred embodiments of the present invention will be described based on the drawings.

FIG. 5 shows the configuration of a preferred embodiment of the present invention.

In FIG. 5, an ignition device 3, an ignition coil 4, and a power distributor 5 included in the ignition section are the same as those in the conventional device shown in FIG. 1, so the same reference numerals are given and a description thereof will be omitted. Further, the power supply lines of the comparators 42 to 45 are stabilized by the resistor 29 and the Zener diode 32. Also, resistors 24 to 28,
An oscillator is configured by a capacitor 40 and a comparator 45, and the configuration of the DC/DC converter is the same as that shown in FIG. However, the symbols are different from those in FIG.

A pulse signal generation circuit that generates a differential pulse signal in synchronization with engine rotation includes a rotation speed detection circuit having resistors 10 to 15, a diode 34, a Zener diode 33, a capacitor 37, and a comparator 42, and a capacitor 38, a resistor 16, and a diode. 50
and a differential circuit having the following functions.

A rotational speed-voltage conversion circuit that generates a signal at a level corresponding to the engine rotational speed is comprised of resistors 17 to 21, a comparator 43, a transistor 46, and a capacitor 39.

An operating time determining circuit for the DC/DC converter, which together with the DC/DC converter constitutes an auxiliary ignition signal generation circuit, is composed of resistors 22, 23 and a comparator 44.

The collector voltage _V1 of the power transistor 3b of the ignition device 3 is divided by resistors 10 and 11,
It is applied to the non-inverting terminal of the comparator 42 via the diode 34. A capacitor 37 and a resistor 1 are connected between the non-inverting terminal of the comparator 42 and GND.
2. A Zener diode 33 is connected to smooth the non-inverting terminal voltage _V7 .

A voltage obtained by dividing the Zener voltage Vz of the Zener diode 32 by the resistors 13 and 14 is applied to the inverting terminal of the comparator 42 as a reference voltage.
Figure 6 p shows the non-inverting terminal voltage V ₇ and the inverting terminal voltage V ₆
+u is shown. Figures p to t are at low speed, and figures u to y
The figure is at high speed.

As shown in figures p and u, the output terminal of the comparator 42 becomes high level in the section where V ₇ >V ₆ . The output voltage of comparator 42 is
8. Comparator 4 via the differential circuit of resistor 16
It is applied to the non-inverting terminals 3 and 44. differential voltage
V ₈ is compared with the inverted terminal voltage V ₉ of the comparator 43, and the output voltage V ₁₀ of the comparator 43 becomes high level in the interval of V ₈ >V ₉ . Note that q and v in FIG. 6 show the non-inverted terminal voltage waveform and inverted terminal voltage waveform of the comparator 43, and r and w show the output voltage waveform of the comparator 43.

The peak value of the differential voltage _V8 is the value obtained by dividing the Zener voltage Vz of the Zener diode 32 by the resistors 15 and 16, and the charging time constant is also determined by the resistors 15 and 16 and the capacitor 38.
The inverted terminal voltage of V ₉ and the Zener voltage Vz of resistor 1
Since the voltage is divided by voltages 7 and 18, the period in which the output terminal of the comparator 43 is at a high level is a certain period of time. Furthermore, when V ₁₀ becomes high level, the base current flows to the transistor 46 via the resistors 19 and 20, the transistor 46 turns on, and the resistor 2
1, a capacitor 39 is charged.

The charge in the capacitor 39 is constantly discharged through the resistor 23, but the transistor 46 is turned ON for a certain period of time every cycle to charge the capacitor, so the voltage charged in the capacitor 39 increases as the engine speed increases. Furthermore, when the key switch is ON and the engine is at 0 rpm, the charging voltage of the capacitor 39 is the Zener voltage.
The voltage is obtained by dividing Vz by the resistors 22 and 23, and the minimum value of the charging voltage of the capacitor 39 is limited by this divided voltage. The maximum operating time of the DC/DC converter is determined by comparing the divided voltage V ₁₁ by the resistors 22 and 23 and the differential waveform V ₈ .

Non-inverting terminal voltage of comparator 44 at low speed
V ₈ and the inverting terminal voltage V ₁₁ are shown in FIG. 6s. _V8 >
In the section where V ₁₁ , the output terminal of the comparator 44 becomes high level, and this high level section
This is the operating time of the DC/DC converter.

FIG. 6t shows the output terminal waveform of the comparator 44. At high speeds, the relationship between V ₈ and V ₁₁ becomes the waveform shown in FIG. 6x, and the output terminal waveform of the comparator 44 also has a high-level period shorter than that at low speeds, as shown in FIG. 6y.

The speed characteristics of the operating time of the DC/DC converter of the device in this example configured as above are as follows:
The characteristics are shown by the dashed line in FIG. That is,
The device in this embodiment superimposes the output signal of the rotation speed-voltage conversion circuit on the reference voltage of the comparator 44, thereby increasing the rotation speed of the engine.
It becomes possible to reduce the operating time of the DC/DC converter within the facing time of the rotor 5a and the side plug 5b, and it also becomes possible to arbitrarily limit the maximum operating time of the DC/DC converter. Therefore, energy loss from startup to low speed can be reduced. Further, in this embodiment, since a method is adopted in which the output signal of the rotation speed/voltage conversion circuit is superimposed on the reference voltage of the comparator 44, the operation of the DC/DC converter does not become unstable. Furthermore, in the embodiment described above, when the inverting terminal voltage V ₁₁ of the comparator 44 exceeds the peak value of the non-inverting terminal voltage V ₁₈ , the operation of the DC/DC converter is stopped.
Since there is no need to stop the DC/DC converter,
A stop circuit is not required, and miniaturization is possible.

〔Effect of the invention〕

As explained above, according to the present invention, it is possible to generate an appropriate ignition signal in accordance with the rotation of the engine, so there is an excellent effect that energy loss can be suppressed to a minimum.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of the conventional device, Figs. 2 and 3 are waveform diagrams of each part of the device shown in Fig. 1, respectively, and Fig. 4 is the operation of the DC/DC converter of the conventional device and the device according to the present invention. FIG. 5 is a diagram showing an embodiment of the present invention, and FIG. 6 is a waveform diagram of each part of the apparatus shown in FIG. 5. 3...Ignition device, 3a...Pickup coil, 3
b...Power transistor, 4...Ignition coil, 5...
Power distributor, 5a... Rotor, 5b... Side plug, 6
~9...Spark plug, 35~36, 42~45...Comparator, 39,49...Step up transformer.

Claims (1)

[Claims] 1. An ignition unit that sequentially supplies an ignition signal synchronized with engine rotation between the ignition plug electrodes of each cylinder to short-circuit the electrodes of each ignition plug, and an auxiliary ignition unit that maintains the discharge loop of the ignition plug due to the short-circuit between the electrodes. A non-contact ignition device for an internal combustion engine, which includes an auxiliary ignition section that supplies a signal to the ignition section, and a pulse signal generation circuit that generates a differential pulse signal in synchronization with the rotation of the engine, and a pulse signal generation circuit that generates a differential pulse signal in synchronization with the engine rotation speed. A rotation speed-voltage conversion circuit that generates a level signal, and an auxiliary ignition signal generation circuit that compares the reference level and the level of the differential pulse signal and generates an auxiliary ignition signal when the level of the differential pulse signal exceeds the reference level. constitutes an auxiliary ignition section, and superimposes the output signal of the rotation speed-voltage conversion circuit on the reference level of the auxiliary ignition signal generation circuit, thereby increasing the duration of the discharge loop at least in the high rotation range of the engine. A non-contact ignition device for an internal combustion engine, characterized in that it gradually decreases as the ignition increases.