JPH04143459A - Ignition device for internal combustion engine - Google Patents

Abstract

PURPOSE:To prevent destruction of a thyristor as a switching element by furnishing a master means to master the output of a converting means in synchronization with ignition signal, and hindering the secondary current of a converting means transformer at the ignition timing from flowing into the switching element together with the discharge current from a capacitor. CONSTITUTION:An ignition signal generator circuit 11 generates an ignition signal at the ignition timing of an engine, and in conformity to this ignition signal a trigger circuit 12 generates a trigger signal to trigger a thyristor 9. When the thyristor 9 is triggered, electric charges on a capacitor 7 are released, and the discharge current flows into the thyristor 9. Therein the output of an oscillator circuit 2 is suppressed through the action of an inverter 13 and an AND circuit, 14. so that the output of a drive circuit 3 in response thereto remains out of emission, and no primary and secondary currents of a transformer 5 will be generated. This prevents destruction of thyristor 9.

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 an ignition device for an internal combustion engine.
The present invention relates to a capacitor discharge type ignition device for an internal combustion engine that charges a capacitor by switching a C converter multiple times.

[Prior Art] FIG. 3 is a configuration diagram showing a conventional ignition device for an internal combustion engine. In the figure, (1) is a battery, (2) is an oscillation circuit that is connected to this battery (1) and generates drive pulses,
(3) is a drive circuit that is connected to this oscillation circuit (2) and battery (1) and generates a drive signal; (4) is a first switching element that is driven by the drive signal from drive circuit (3), e.g. The transistor (5) is a transformer whose primary side is connected to the collector of this transistor (4), and (2) to (5) are DC-DC converters as conversion means.
Configure the converter. (6) is a rectifier diode connected to the secondary side of transformer (5), (7) is a capacitor connected between the cathode of diode (6) and the ground, (
8) is an ignition coil whose primary side is connected to one end of a capacitor (7), (9) is a second switching element connected between the primary side of this ignition coil (8) and the ground, for example, SIRIS; (10) ) is a spark plug provided on the secondary side of the ignition coil (8), (11) is connected to the battery (1),
An ignition signal generation circuit (12) is connected to the battery (1) and the ignition signal generation circuit (12) and generates a trigger signal in response to the ignition signal. In the circuit, (11) and (12) constitute ignition signal generating means.

Next, the operation of the conventional ignition system for an internal combustion engine shown in FIG. 3 will be explained with reference to FIG. 4.

The transistor (4) is driven by a drive signal from the drive circuit (3) in response to a drive pulse as shown in FIG. 4B from the oscillation circuit (2), and the transformer (5) is energized.
Cut off. At this time, the current generated on the primary side of the transformer (5) as shown in Fig. 4C is converted to the secondary side of the transformer (5) as shown in Fig. 4, and is further passed through the diode (6).
The capacitor (7) is charged as shown in FIG. 4E.

The ignition signal generation circuit (11) generates an ignition signal as shown in FIG. 9). When the thyristor (9) is triggered, the electric charge stored in the capacitor (7) is discharged along the path of capacitor (7) → primary side of ignition coil (8) → thyristor (9) → capacitor (7). .

At this time, a discharge current as shown in FIG. 4F flows into the thyristor (9) from the capacitor (7).

This generates a high voltage on the secondary side of the ignition coil (10), causing the ignition plug (15) to ignite.

[Problems to be Solved by the Invention] Since the conventional ignition device for an internal combustion engine is configured as described above, the total current flowing through the thyristor (9) is as shown in Fig. 4G.
As shown in Time 1. 1. In this case, there is no problem with the current flowing only from the capacitor (7), but at time t2, the current from the capacitor (7)
) is the sum of the current from the transformer (5) and the secondary current of the transformer (5),
There is a risk that the current peak value will become high as shown in Figure 4G and the thyristor (9) will be destroyed, so the current capacity of the thyristor (9) must be increased, which increases the size and increases the cost. It also had the problem of being expensive.

This invention was made to solve the above-mentioned problems, and an object thereof is to obtain an ignition device for an internal combustion engine that can prevent destruction of a thyristor as a switching element.

[Means for Solving the Problems] An ignition device for an internal combustion engine according to the present invention includes a converting means for boosting the voltage of a DC power source to a predetermined voltage, a capacitor charged by the output of the converting means, and a capacitor for increasing the voltage of the internal combustion engine. ignition signal generation means for generating an ignition signal in synchronization with the ignition signal; a switching element that is electrically connected by the ignition signal to discharge the capacitor through the primary side of the ignition coil; and an output of the conversion means in synchronization with the ignition signal. and masking means for masking.

[Function] In this invention, a masking means is provided for masking the output of the converting means in synchronization with the ignition signal, so that the secondary current of the transformer of the converting means does not flow into the switching element together with the discharge current from the capacitor at the ignition timing. Make it.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings. 1st
The figure is a configuration diagram showing one embodiment of the present invention, and (1) to
(12) is the same as described above. In this embodiment, an inverter (13) and an AND circuit (14) are used as masking means.
), the output side of the ignition signal generation circuit (11) is connected to one input terminal of the AND circuit (14) via the inverter (13), and the output side of the oscillation circuit (2) is connected to one input terminal of the AND circuit (14).
4), and connect it to the other input terminal of
14) is connected to the drive circuit (3).

Next, the operation of one embodiment of the present invention shown in FIG. 1 will be explained with reference to FIG. 2. A drive circuit that responds to a drive pulse as shown in FIG. 2B from the zero oscillation circuit (2) The transistor (4) is driven by the drive signal as shown in FIG. 2B from (3), and the transformer (5) is energized and cut off.

At this time, the current generated on the primary side of the transformer (5) as shown in Figure 2C is converted to the secondary side of the transformer (5) as shown in the second diagram, and is further passed through the diode (6). The capacitor (7) is charged as shown in FIG. 2E.

The ignition signal generation circuit (11) generates an ignition signal as shown in FIG. 9). When the thyristor (9) is triggered, the electric charge stored in the capacitor (7) is discharged along the path of capacitor (7) → primary side of ignition coil (8) → thyristor (9) → capacitor (7). .

At this time, a discharge current as shown in FIG. 2F flows into the thyristor (9) from the capacitor (7).

This generates a high voltage on the secondary side of the ignition coil (10), causing the ignition plug (15) to ignite. What is noteworthy here is that when the ignition signal is generated, the inverter (13)
, the output of the oscillation circuit (2) is suppressed by the action of the AND circuit (14), and the drive circuit (3) responds to this.
The output of the transformer (5) is no longer output as shown in FIG. 2B, and the primary current and secondary current of the transformer (5) are not generated as shown in FIGS. 2c and 2D. Therefore, at all times t3, t2, and t, the current flowing into the thyristor (9) is only the discharge current from the capacitor (7);
) will be as shown in Figure 2G, and the thyristor (9) will not be destroyed.

[Effects of the Invention] As described above, according to the present invention, there is a converting means for boosting the voltage of a DC power source to a predetermined voltage, a capacitor charged by the output of the converting means, and an ignition device that is ignited in synchronization with the rotation of the internal combustion engine. ignition signal generation means for generating a signal; a switching element that is electrically connected by the ignition signal to discharge the capacitor through the primary side of the ignition coil; and mask means for masking the output of the conversion means in synchronization with the ignition signal. Therefore, there is an effect that an ignition device for an internal combustion engine that can prevent destruction of the switching element can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a configuration diagram showing an embodiment of the present invention, FIG. 2 is a signal waveform diagram for explaining the operation of FIG. 1, FIG. 3 is a configuration diagram showing a conventional ignition system for an internal combustion engine, and FIG. FIG. 4 is a signal waveform diagram for explaining the operation of FIG. 3. In the figure, (1) is the battery, (2) is the oscillation circuit, (
3) is a drive circuit, (4) is a transistor, (5) is a transformer, (7) is a capacitor, (8) is an ignition coil,
(9) is a thyristor, (11) is an ignition signal generation circuit, (
12) is the trigger circuit, (13) is the inverter, (14)
is an AND circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of Claims] Conversion means for boosting the voltage of a DC power source to a predetermined voltage; a capacitor charged by the output of the conversion means; and ignition signal generation means for generating an ignition signal in synchronization with the rotation of an internal combustion engine. , a switching element that is electrically connected by the ignition signal to discharge the capacitor through the primary side of the ignition coil; and a masking device that masks the output of the conversion means in synchronization with the ignition signal. Ignition system for internal combustion engines.