JP2781265B2 - Ignition device for internal combustion engine - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ignition device for an internal combustion engine, and more particularly to an ignition device for a capacitor discharge type internal combustion engine having an extended discharge duration.

[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 connected to this battery (1), and an oscillation circuit for generating a drive pulse, and (3) is connected to this oscillation circuit (2) and the battery (1) to drive A drive circuit for generating a signal, (4) a first switching element, for example, a transistor driven by a drive signal from the drive circuit (3), and (5) a primary side connected to the collector of the transistor (4) Transistors (2) to (5) are DC as conversion means
-Configure a DC converter. (6) and (7) are rectifying diodes connected to the secondary side of the transformer (5),
(8) and (9) are capacitors connected between the cathodes of the diodes (6) and (7) and the ground, respectively, and (10) is 1
An ignition coil whose secondary side is connected to one end of a capacitor (8); (11) a second switching element such as a thyristor connected between the primary side of this ignition coil (10) and the ground;
(12) is a diode for preventing pulsating current and voltage connected in parallel to the primary side of the ignition coil (10), and (13) is a discharge time duration connected between the cathodes of the diodes (7) and (12). (14) is a diode for maintaining the discharge time connected between the cathode of the diode (7) and the anode of the diode (12), and (15) is a spark plug provided on the secondary side of the ignition coil (10). , (16) are connected to the battery (1) and generate an ignition signal in synchronization with the rotation of the internal combustion engine. (17) is connected to the battery (1) and the ignition signal generating circuit (16). And a trigger circuit for generating a trigger signal in response to the ignition signal, wherein (16) to (17) constitute ignition signal generating means.

Next, the operation of the conventional ignition device for an internal combustion engine shown in FIG. 3 will be described with reference to FIG. 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 energizes and cuts off the transformer (5). At this time, the primary 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), and further converted via the diodes (6) and (7), respectively. The capacitors (8) and (9) are charged. FIG. 4D shows the charging voltage of the capacitor (9).

The ignition signal generating circuit (16) generates an ignition signal as shown in FIG. 4A in accordance with the ignition timing of the engine, and in response to the ignition signal, the trigger circuit (17) generates a trigger signal to generate a thyristor ( 11) Trigger. When the thyristor (11) is triggered, the electric charge charged in the capacitor (8) is discharged through the path of the capacitor (8) → primary side of the ignition coil (10) → thyristor (11) → capacitor (8). The electric charge charged in the capacitor (9) is changed to the capacitor (9)
→ Inductor (13) → Primary side of ignition coil (10) → Thyristor (11) → Discharge in the path of capacitor (9). As a result, an output voltage and an output current are generated on the secondary side of the ignition coil (10) as shown in FIGS.
5) Ignite. At this time, the primary side of the ignition coil (10) →
Diode (14) → Inductor (13) → Ignition coil (1
The discharge sustaining current flows on the primary path of (0). This extends the discharge duration of the spark plug (15).

[Problem to be Solved by the Invention] Since the conventional ignition device for an internal combustion engine is configured as described above, the primary side of the ignition coil (10) → the diode (1)
4) → Inductor (13) → Discharge continuous current flows on the primary path of ignition coil (10), and discharge continues on the secondary side of ignition coil (10). Is supplied and the capacitors (8) and (9) are charged, the discharge sustaining current stops, and the discharge stops temporarily as shown in FIGS. 4E and 4F.

The present invention has been made in order to solve the above problems, and an object of the present invention is to provide an ignition device for an internal combustion engine in which discharge is not cut off under the influence of a DC-DC converter during discharge continuation. .

[Means for Solving the Problems] An ignition device for an internal combustion engine according to the present invention opens and closes a supply path of a DC power supply and generates a boosted voltage at a time of opening every predetermined period, and the conversion means. First and second capacitors connected to the converter and charged by the output of the converter, generating an ignition signal in synchronization with rotation of the internal combustion engine, and performing a closing operation of the converter in synchronization with the ignition signal. The ignition signal generating means to be started and the ignition coil
The first and second capacitors are connected to each other through the secondary side and are turned on by the ignition signal to charge the first and second capacitors.
A switching element discharging through the secondary side, an inductor connected in series between the second capacitor and the primary side of the ignition coil, and an anode connected to a connection point between the primary side of the ignition coil and the switching element. , A diode having a cathode connected to a connection point between the second capacitor and the inductor, wherein the switching means in the conversion means is provided with first and second switching means.
The circuit closes at the same time as the discharge of the electric charge charged to the capacitor, and opens after the electromotive force generated in the inductor due to the discharge of the stored electric charge is discharged through the primary side of the ignition coil and the diode. The power is in a non-conductive state during discharging.

[Operation] In the present invention, the operation of the conversion means is started in synchronization with the ignition timing of the ignition signal of the ignition signal generation means, and while the discharge continues on the secondary side of the ignition coil, energy is transferred from the conversion means to the capacitor. Is not supplied to prevent a temporary stop of the discharge sustaining current.

Embodiment An embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing one embodiment of the present invention, and (1)
(17) are the same as described above. In this embodiment, the output side of the ignition signal generation circuit (16) is connected to the oscillation circuit (2) of the DC-DC converter, and the operation of the oscillation circuit (2) is controlled by the ignition signal generation from the ignition signal generation circuit (16). Start in synchronization with the ignition timing.

Next, the operation of the embodiment of the present invention shown in FIG. 1 will be described with reference to FIG. In response to a drive pulse as shown in FIG. 2B from the oscillation circuit (2) generated in synchronization with the ignition timing of the ignition signal as shown in FIG. 2A output from the ignition signal generation circuit (16). The transistor (4) is driven by a drive signal from the drive circuit (3) to turn on and off the transformer (5). At this time, a signal generated on the primary side of the transformer (5) as shown in FIG.
The secondary current is converted to the secondary side of the transformer (5), and further charged to the capacitors (8) and (9) via the diodes (6) and (7), respectively. FIG. 2D shows the charging voltage of the capacitor (9). The time when the drive pulse output from the oscillation circuit (2) turns on the transistor (4) via the drive circuit (3) is equal to two times of the ignition coil (10).
Set to be longer than the discharge duration that occurs on the next side.

The ignition signal generating circuit (16) generates an ignition signal as shown in FIG. 2A in accordance with the ignition timing of the engine, and in response to the ignition signal, the trigger circuit (17) generates a trigger signal to generate a thyristor ( 11) Trigger. When the thyristor (11) is triggered, the electric charge charged in the capacitor (8) is discharged through the path of the capacitor (8) → the primary side of the ignition coil (10) → the thyristor (11) → the capacitor (8). The electric charge charged in the capacitor (9) is changed to the capacitor (9)
→ Inductor (13) → Primary side of ignition coil (10) → Thyristor (11) → Discharge in the path of capacitor (9). As a result, a high voltage and a high current as shown in FIGS. 2E and 2F are generated on the secondary side of the ignition coil (10), and the ignition plug (15) is ignited. At this time, the primary side of the ignition coil (10) → the diode (14) → the inductor (13) → 1 of the ignition coil (10)
A discharge sustaining current flows in the path on the next side. This extends the discharge duration of the spark plug (15). As described above, in this embodiment, by controlling the operation of the oscillation circuit (2) as described above, energy is transferred from the DC-DC converter to the capacitor (9) during the discharge on the secondary side of the ignition coil (10). Not supplied, and therefore FIG.
As shown in (1), the discharge is not cut off temporarily.

[Effects of the Invention] As described above, according to the present invention, a conversion unit that opens and closes a supply path of a DC power supply to generate a boosted voltage at a time of opening every predetermined period, and is connected to the conversion unit. First and second capacitors charged by the output of the conversion means, and an ignition signal generation for generating an ignition signal in synchronization with rotation of the internal combustion engine and for starting a closing operation of the conversion means in synchronization with the ignition signal A switching element that is connected to the conversion means via the primary side of the ignition coil, conducts by the ignition signal, and discharges the charges charged in the first and second capacitors through the primary side of the ignition coil; An inductor is connected in series between the second capacitor and the primary side of the ignition coil, and an anode is connected to a connection point between the primary side of the ignition coil and the switching element, and the second capacitor and the inductor are connected to each other. A diode whose cathode is connected to a connection point with the rectifier, wherein the opening / closing means in the conversion means is closed at the same time as the discharge of the electric charge charged in the first and second capacitors is started,
Since the electromotive force generated in the inductor due to the discharge of the stored electric charge is discharged through the primary side of the ignition coil and the diode, the circuit is opened, and the switching element is in a non-conductive state during the discharge, so that the ignition coil (10 ) Primary side → diode → inductor (13) → discharge continuous current flowing through the primary side path of the ignition coil (10) does not stop, so that the discharge is affected by the conversion means during the discharge continuation. There is an effect that an ignition device for an internal combustion engine which is not cut off temporarily can be obtained.

[Brief description of the drawings]

1 is a block 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 block diagram showing a conventional ignition device for an internal combustion engine, FIG. 4 is a signal waveform diagram for explaining the operation of FIG. In the figure, (1) is a battery, (2) is an oscillation circuit,
(3) is a drive circuit, (4) is a transistor, (5)
Is a transformer, (8) and (9) are capacitors, (10) is an ignition coil, (11) is a thyristor, (13) is an inductor,
(14) is a diode, (16) is an ignition signal generation circuit, (1
7) is a trigger circuit. In the drawings, the same reference numerals indicate the same or corresponding parts.

Continuation of front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F02P 1/00-3/12 F02P 9/00-17/00

Claims (1)

(57) [Claims] 1. A conversion means for opening and closing a supply path of a DC power supply to generate a boosted voltage at the time of opening every predetermined period, and a conversion means connected to the conversion means and charged by an output of the conversion means. First and second capacitors, an ignition signal generating means for generating an ignition signal in synchronization with the rotation of the internal combustion engine, and starting a closing operation of the conversion means in synchronization with the ignition signal; Connected via the primary side of
A switching element that conducts by the ignition signal and discharges the electric charges charged in the first and second capacitors through the primary side of the ignition coil; and a switching element that connects the second capacitor and the primary side of the ignition coil. A diode having an anode connected to a connection point between the primary side of the ignition coil and the switching element, and a cathode connected to a connection point between the second capacitor and the inductor; And an opening / closing means in the conversion means,
The circuit is closed at the same time as the discharge of the electric charge charged in the capacitor, and is opened after the electromotive force generated in the inductor by the discharge of the stored electric charge is discharged through the primary side of the ignition coil and the diode. An ignition device for an internal combustion engine, wherein the switching element is in a non-conductive state during discharge of the electromotive force.