JP2010101212A - Ignition device for internal combustion engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To surely ignite in a lean burn engine, even if "blow off phenomenon" occurs by adapting a general self-excited thyristor series inverter type multiple spark ignition device to an internal combustion engine for an automobile. <P>SOLUTION: In this self-excited thyristor series inverter type ignition device I for the internal combustion engine making a thyristor series inverter circuit self-excited using an ignition coil as a load, and generating multiple spark discharge in a gap g of discharge electrodes 29a, 29b of a spark plug at high voltage generated on the secondary side of the ignition coil, multiple spark discharge is generated in the gap g of the discharge electrodes 29a, 29b by driving with a direct current power source, and the spark discharge is started upon receipt of ignition signal S1 from an engine computer with a first trigger element 13. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention is a self-excited thyristor series in which a thyristor series inverter circuit is self-excited by using an ignition coil as a load, and a plurality of spark discharges are blown into a gap between discharge electrodes of a spark plug with a high voltage generated on the secondary side of the ignition coil. The present invention relates to an inverter type ignition device for an internal combustion engine.

In recent years, so-called lean burn engines (lean burn engines) in which the air-fuel ratio is set to be extremely thin are being adopted as internal combustion engines mounted on vehicles. However, since this type of engine is not very efficient in ignition, a high energy type ignition device is required. In view of this, a multi-discharge ignition device has been proposed in which the high-voltage output of the DC-DC converter is superimposed on the secondary output of the ignition coil generated by the classic current interruption principle (see, for example, Patent Document 1). ).
JP-A-8-68372

  That is, by interrupting the primary current of the ignition coil, a high voltage of several kV generated on the secondary side thereof causes a discharge breakdown in the gap between the discharge electrodes of the spark plug so that the discharge current is generated from the secondary side of the ignition coil. After starting to flow, while maintaining a DC voltage (usually about 500 V or more) higher than the discharge sustaining voltage value capable of maintaining the discharge state by the separately provided booster circuit, the output current from the booster circuit is the ignition coil discharge current. Are additively superimposed. In fact, according to such a system, a large amount of discharge energy can be obtained in the spark plug for a relatively long time, so that the ignitability of the fuel is improved and, consequently, the fuel efficiency is also improved.

  Combustion in each cylinder combustion chamber of an internal combustion engine proceeds from initial discharge sparks to the spark plug to initial combustion, medium-term combustion, and main combustion. A sudden change in airflow occurs and the discharge spark generated in the gap between the discharge electrodes of the spark plug is blown out, despite the fact that the overlap discharge current is supplied by the DC-DC converter. "Phenomenon" may occur. When such a blow-out phenomenon occurs, the discharge is interrupted without being extended to a predetermined duration, and the intended combustion energy cannot be obtained.

  Therefore, in order to solve the above problems, a high-speed repetitive discharge method is adopted, and even if a “blown-out phenomenon” occurs, it is possible to re-discharge by repeating the discharge thereafter. Can be considered.

  As a means for obtaining high-speed repetitive discharge, a self-excited thyristor series inverter type multiple spark ignition device, which is general as an ignition device for an external combustion engine using oil or the like as a fuel, is known.

  FIG. 2 is a schematic configuration diagram of a conventional self-excited thyristor series inverter type multiple spark ignition device.

  The operation of the conventional self-excited thyristor series inverter type multiple spark ignition device will be described with reference to FIG.

  The self-excited thyristor series inverter ignition device I1 charges the capacitor 14 from one terminal 100a of a high-voltage AC power source 100 such as a commercial power source through a resistor 2 and a resistor 7 in a half cycle period of AC. When the charging voltage of the capacitor 14 reaches the threshold voltage (breakover voltage) of the trigger element 13, the trigger element 13 becomes conductive, and the resonance charge of the capacitor 14 is discharged to the gate of the thyristor 6 through the resistor 9. And let it flow as a trigger current.

  When the trigger current flows, the resonant capacitor 8 is charged through the path of the resonant inductor 5, the thyristor 6, the resonant capacitor 8, and the power supply other terminal 100b. This charging current oscillates due to resonance of the resonant inductor 5 and the resonant capacitor 8 and turns off when the current of the thyristor 6 is reversed when the charging current is reversed. Then, the charged charge of the resonant capacitor 8 is discharged through the primary winding 21 of the ignition coil, a high voltage is generated in the secondary winding 23, and a spark discharge is caused in the gap g between the discharge electrodes 29a and 29b.

  At the same time, a voltage is generated in the return winding 22 of the ignition coil with the + and-polarities shown in the drawing with respect to the primary winding. At this time, the voltage is short-circuited by the Zener diode 18 via the resistor 16 and is connected to the thyristor. The gate 6 is not affected.

  Next, due to resonance between the resonant capacitor 8 and the primary winding 21, the resonance current is inverted, and a voltage is generated in the primary winding with (+) and (−) polarity as shown in the figure. In addition, a high voltage is generated in the secondary winding 23, and a spark discharge is generated in the gap g between the discharge electrodes 29a and 29b of the spark plug. At the same time, the feedback winding 22 is also shown in the (+) and (-) polarity. A voltage is generated, and the capacitor 15 is charged through the path of the diode 11, the capacitor 15, and the resistor 16. When the voltage of the feedback winding 22 becomes zero, the charge stored in the capacitor 15 accumulated so far flows into the gate of the thyristor 6 through the resistor 9 and turns on the thyristor 6. Thereafter, this operation is repeated.

  The above-described conventional self-excited thyristor series inverter type multiple spark ignition device uses a commercial AC power supply as a power supply, and discharge is synchronized with the power supply frequency when the power supply voltage is equal to or higher than the voltage corresponding to the threshold voltage of the trigger element 13. Once the discharge is started, it will continue intermittently in synchronism with the power source as long as the power source exists.

  On the other hand, the power source of the internal combustion engine for automobiles is a DC power source, and the start of ignition requires a time accurately calculated by an engine computer or the like, and the discharge duration is generally as short as several ms. For this reason, the conventional self-excited thyristor series inverter ignition device I1 is applied to an internal combustion engine for automobiles, and even if an attempt is made to ignite reliably even if a “blown-off phenomenon” occurs in a lean combustion engine, the application thereof The current situation is difficult.

  The present invention has been proposed in view of the above, and a general self-excited thyristor series inverter type multiple spark ignition device is adapted to an internal combustion engine for an automobile so that even if a “blown-off phenomenon” occurs in a lean combustion engine, it is ensured. An object of the present invention is to provide an ignition device for an internal combustion engine that can be ignited.

  In order to achieve the above object, according to the present invention, a thyristor series inverter circuit is self-excitedly oscillated with an ignition coil as a load, and a discharge electrode of a spark plug is generated with a high voltage generated on the secondary side of the ignition coil. In a self-excited thyristor series inverter type internal combustion engine ignition device that blows a plurality of spark discharges in a gap between the two, a spark source is driven by a DC power source to cause a plurality of spark discharges in the gap between the discharge electrodes. The first trigger element receives the ignition signal from the first trigger element and starts.

  According to a second aspect of the present invention, in the first aspect of the present invention, the spark discharge is such that the second trigger element receives a stop signal from the engine computer and stops.

  In the ignition device for an internal combustion engine according to the present invention, the thyristor series inverter circuit is driven by a DC power source, and spark discharge is started when the first trigger element receives the ignition signal from the engine computer, and the stop signal is sent to the second trigger. Since the element is received and stopped, high-speed repetitive discharge can be performed in the gap between the discharge electrodes, and the blow-off phenomenon during the discharge hardly occurs, so that ignition can be performed with good ignitability.

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

  FIG. 1 is a schematic configuration diagram of an ignition device for an internal combustion engine according to the present invention. In FIG. 1, the same components as those in FIG. 2 of the conventional example are denoted by the same reference numerals.

  FIG. 1 differs from FIG. 2 of the conventional example in that the power source is DC using the DC-DC converter circuit 1 that boosts the battery power source 40, and the trigger element 13 that starts discharge. In addition, the trigger element 24 that terminates the discharge is configured to operate with a signal from the trigger signal generation unit 30. The trigger signal generator 30 receives the ignition signal S1 from the engine computer (ECU), generates the trigger signal PC1 at an appropriate time, receives the stop signal S2 from the ECU, and receives the trigger signal PC2 at an appropriate time. Is generated.

  Hereinafter, the operation of the internal combustion engine ignition device I according to the present invention will be described with reference to FIG. The capacitor 14 is charged from one terminal 1 a of the DC-DC converter circuit 1 through the resistors 2 and 7. The capacitor 14 is connected to the gate of the thyristor 6 through the trigger element 13 and the resistor 9, and the trigger element 13 receives the ignition signal S1 from the ECU and receives the trigger signal PC1 output from the trigger signal generator 30. In response to this, the trigger current of the thyristor 6 is supplied at an appropriate time to turn it on. That is, the start of discharge can be determined at an arbitrary time based on a signal from the ECU.

  In the present embodiment, as will be described later, this trigger signal PC1 is only necessary at the start of discharge, and is not necessary for continuing the subsequent discharge, and is necessary and sufficient for turning on the thyristor 6. A short pulse is used, and after the turn-on, it is turned off.

  When the trigger current flows, the resonant capacitor 8 is charged through the path of the resonant inductor 5, the thyristor 6, the resonant capacitor 8, and the other terminal 1b of the DC-DC converter circuit 1. This charging current oscillates due to resonance of the resonant inductor 5 and the resonant capacitor 8 and turns off when the current of the thyristor 6 is reversed when the charging current is reversed. Then, the charge of the resonant capacitor 8 is discharged through the primary winding 21 of the ignition coil, a high voltage is generated in the secondary winding 23, and a spark discharge is generated in the gap g between the discharge electrodes 29a and 29b of the spark plug. Wake up.

  At the same time, a voltage is generated in the feedback winding 22 of the ignition coil with the + and-polarities shown in the drawing with respect to the primary winding. The gate 6 is not affected.

  Next, due to resonance between the resonant capacitor 8 and the primary winding 21, the resonance current is inverted, and a voltage is generated in the primary winding with (+) and (−) polarity as shown in the figure. In addition, a high voltage is generated in the secondary winding 23, and a spark discharge is generated in the gap g between the discharge electrodes 29a and 29b of the spark plug, and at the same time, the feedback winding 22 is also shown with (+) and (-) polarity. A voltage is generated, and the capacitor 15 is charged through the path of the diode 11, the capacitor 15, and the resistor 16. When the voltage of the feedback winding 22 becomes zero, the charge stored in the capacitor 15 accumulated so far flows into the gate of the thyristor 6 through the resistor 9 and turns on the thyristor 6. Thereafter, this operation is repeated.

  Here, in the present invention, the power source is a DC power source, and the discharge is continuously continued completely. Therefore, the trigger element 24 is installed in the direction opposite to the Zener diode 18 in order to end the discharge.

  The trigger element 24 receives the stop signal S2 from the ECU and receives the trigger signal PC2 output from the trigger signal generator 30 at an appropriate time. When the trigger element 24 is turned on, both ends of the Zener diode 18 are both connected. In a short-circuit state. By this operation, the voltage generated in the feedback winding 22 is canceled, that is, by invalidating the operation of the feedback winding 22, the capacitor 15 for re-turning on the thyristor 6 is not charged as described above. The discharge stops. That is, the discharge stop timing can be arbitrarily determined.

  As described above, the internal combustion engine ignition device I according to the present invention drives the thyristor series inverter circuit with a DC power source, and spark discharge starts when the trigger element 13 receives the ignition signal S1 from the ECU, Since the trigger element 24 receives the stop signal S2 and stops, the gap g between the discharge electrodes 29a and 29b can be repeatedly discharged at high speed, and the blow-off phenomenon during the discharge hardly occurs and ignition is ignited. It can be a good one.

It is a schematic block diagram of the ignition device for internal combustion engines of this invention. It is a schematic block diagram of the conventional self-excited thyristor series inverter type multiple spark ignition device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 DC-DC converter circuit 1a 1 terminal of DC-DC converter circuit 1b Other terminal of DC-DC converter circuit 2 Resistance 5 Resonance inductor 6 Thyristor 7 Resistance 8 Resonance capacitor 9 Resistance 11 Diode 13 Trigger element 14 Capacitor 15 Capacitor 16 Resistance 18 Zener diode 21 Primary winding 22 Feedback winding 23 Secondary winding 24 Trigger element 29a, 29b Discharge electrode 30 Trigger signal generator 40 Battery power supply I Internal combustion engine ignition device PC1 Ignition trigger signal PC2 Stop trigger signal S1 Ignition Signal S2 Stop signal g Discharge electrode gap

Claims (2)

A self-excited thyristor series inverter type internal combustion engine that causes a thyristor series inverter circuit to self-oscillate using an ignition coil as a load, and causes a plurality of spark discharges to fly between the discharge electrodes of a spark plug with a high voltage generated on the secondary side of the ignition coil. In the engine ignition device,
A plurality of spark discharges are performed in the gaps between the discharge electrodes by being driven by a DC power source, and the spark discharges are started when the first trigger element receives an ignition signal from the engine computer.
An internal combustion engine ignition device.   The ignition device for an internal combustion engine according to claim 1, wherein the spark discharge is stopped when the second trigger element receives a stop signal from the engine computer.

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