JPS626113B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an engine ignition system that has a long discharge duration and a large discharge current value to improve ignition performance.

In general, CDI ignition devices have the advantage of being resistant to plug fouling, but have a short discharge duration and are inferior to current-disruption type ignition devices in terms of ignition ability. Therefore, engine ignition systems that extend the discharge duration have been proposed, but conversely, the discharge current value decreases and the energy density becomes low, so ignition performance cannot be sufficiently improved. There were drawbacks such as reduced stain resistance.

Therefore, an object of the present invention is to provide an engine ignition system that increases ignition energy, particularly discharge duration, and has multiple ignition features without losing the features of CDI.

In order to achieve such an object, the present invention includes a power generation coil that supplies ignition power, a first diode and a second diode that divide and rectify the output of this power generation coil, and a power generation coil that is charged with the rectified output. A first capacitor and a second capacitor forming a first closed circuit that is triggered by a signal voltage generated in the signal coil and causes the charged charge of the first capacitor to flow to the primary coil of the ignition coil. The first capacitor is charged in the opposite direction by the thyristor and the discharged charge discharged in this first closed circuit, and a second closed circuit is formed in which the charged charge flows to the primary coil of the ignition coil. a resistor, a reverse diode, and a signal capacitor charged by a portion of the discharge current flowing through the second closed circuit;
A second thyristor forms a third closed circuit that is triggered by the charging voltage charged in the signal capacitor and causes the charged charge in the second capacitor to flow to the primary coil of the ignition coil. ,
This will be explained in detail below using examples.

FIG. 1 is a circuit diagram showing an embodiment of an engine ignition system according to the present invention. In the figure, 1 is a power generating coil that serves as an ignition power source, 2a and 2b are first and second diodes that rectify the output of the power generating coil 1, respectively, and 3a and 3b are the first and second rectifying diodes, respectively. 2a
and 2b, the first and second capacitors 4 have a primary coil 5 and a secondary coil 6, and the charged charges of the capacitors 3a and 3b are An ignition coil that generates a high voltage to the secondary coil 6 when discharged through the secondary coil 5; 7 an ignition plug that sparks when the high voltage generated in the ignition coil 4 is applied; and 8 an ignition signal that generates an ignition signal. A signal coil, 9 a diode whose anode is connected to one end of this signal coil 8, 10 a gate resistor connected between the cathode of this diode 9 and ground,
11 is a first thyristor that becomes conductive when an ignition signal is applied to its gate; 12 is a reverse diode; 13 is a low resistance resistor connected in series with the reverse diode 12; 14 is a signal capacitor; 15 is a diode, 16 is a second thyristor, and 17 is a cathode of this second thyristor 16.
A diode 18 is connected to the anode of the second thyristor 17, and the anode is connected to the ground.

Note that a first closed circuit is formed by the first capacitor 3a, the first thyristor 11, and the primary coil 5 of the ignition coil 4, and the first capacitor 3
a - the primary coil 5 of the ignition coil 4 - the resistor 13 - the reverse diode 12 constitute a second closed circuit, and the second capacitor 3b - the second thyristor 16 - the primary coil 5 of the ignition coil 4 by the third
form a closed circuit.

Next, the operation of the engine ignition system having the above configuration will be explained with reference to FIGS. 2a to 2d. First, the ignition power generated by the generator coil 1 is divided into two parts and rectified by the first diode 2a and the second diode 2b, respectively. The rectified ignition power charges the first capacitor 3a and the second capacitor 3b, so that the first and second capacitors 3a and 3b maintain a predetermined voltage. On the other hand, when a signal voltage is generated in the signal coil 8 at the ignition timing of the engine, this signal voltage is applied to the gate of the first thyristor 11 via the diode 9. Therefore, this first thyristor 11 becomes conductive. Therefore, the charge in the first capacitor 3a is discharged to the primary coil 5 of the ignition coil 4 via the first thyristor 11 in the conductive state. Therefore, a high voltage is generated in the secondary coil 6 of the ignition coil 4, causing the ignition plug 7 to spark. This discharge current eventually charges the first capacitor 3a in the opposite direction. When the first capacitor 3a is charged in the opposite direction, a current flows in the second closed circuit in the opposite direction to the initial current. charges the signal capacitor 14 to the illustrated polarity through the diode 15. In this way, the exciting current flows through the secondary coil 6 of the ignition coil 4 as shown in Fig. 2a.
An oscillating voltage shown in is generated, causing the spark plug 7 to fly. Then, as the energy stored in the first capacitor 3a attenuates, the discharge eventually stops.
While the signal capacitor 14 is being charged, the ground potential is higher than the potential of the + polarity terminal shown in FIG. 1, but when the phase of the current is reversed again, the time t ₁ shown in FIG. At the position, the ground potential and the potential of the + polarity terminal of the signal capacitor 14 are reversed, so the charge in the signal capacitor 14 is transferred from the gate/cathode of the second thyristor 16 to the signal capacitor 14 via the resistor 13. This second thyristor 1 discharges in a closed circuit at one end.
6 is triggered and becomes conductive. Therefore, due to the conduction of the second thyristor 16, the charge stored in the second capacitor 3b is discharged to the third closed circuit, and thus flows to the primary coil 5 of the ignition coil 4. Therefore, the secondary coil 6 of the ignition coil 4
An oscillating voltage shown in FIG. 2b is generated. As long as the energy of the first capacitor 3a and the second capacitor 3b are the same, this oscillating voltage
The oscillating voltage is similar to the oscillating voltage shown in . Therefore, the voltage generated in the secondary coil 6 of the ignition coil 4 is the oscillating voltage shown in FIG. 2c, which is a combination of the oscillating voltage shown in FIG. 2a and the oscillating voltage shown in FIG. 2b. Therefore, the discharge time is extended by one cycle compared to discharge by a single capacitor. At this time, the voltage is suppressed to a constant value by the discharge gap of the spark plug 7, but the discharge current is doubled as shown in FIG. 2d.

In addition, in the above embodiment, the case where one cycle is extended by the second thyristor has been explained, but for the second thyristor, a second reverse diode, a second resistor, and a second signal capacitor are used. It goes without saying that the discharge time can be extended by sequentially connecting N stages of circuits each including a third thyristor and a third thyristor. It goes without saying that each capacitor can be converted into two plugs by feeding power to separate ignition coils.

As described above in detail, according to the engine ignition device according to the present invention, the discharge current and discharge time can be increased, so that ignition performance can be improved. Furthermore, depending on the design value of the primary inductance of the ignition coil, it is possible to obtain a discharge time equivalent to that of the current cutoff method, and to ignite the engine without impairing the stain resistance of the spark plug, which is a feature of CDI. It has the advantage that it can be carried out reliably.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing an embodiment of an engine ignition system according to the present invention, and FIGS. 2a to 2d are diagrams showing waveforms of various parts in FIG. 1. 1... Generator coil, 2a... First diode, 2
b...Second diode, 3a...First capacitor, 3b...Second capacitor, 4...Ignition coil,
5... Primary coil, 6... Secondary coil, 7... Spark plug, 8... Signal coil, 9... Diode, 10... Resistor, 11... First thyristor, 12... Reverse diode, 13... Resistor, 14... Signal capacitor for,
15...Diode, 16...Second thyristor, 1
7...Diode, 18...Gate resistance. Note that the same reference numerals indicate the same or equivalent parts.

Claims (1)

[Claims] 1. A generator coil that supplies ignition power, a first diode and a second diode that divide and rectify the output of the generator coil, and a first diode that is charged with the rectified output, respectively. capacitor and second
a first thyristor forming a first closed circuit that is triggered by a signal voltage generated in the signal coil and causes the charged charge of the first capacitor to flow to the primary coil of the ignition coil; The first capacitor is charged in the opposite direction by the discharge charge discharged in the circuit, and the charge is transferred to the first capacitor of the ignition coil.
A resistor and a reverse diode that form a second closed circuit that flows through the next coil, a signal capacitor that is charged by a portion of the discharge current that flows through the second closed circuit, and a signal capacitor that is charged by a portion of the discharge current that flows through the second closed circuit. and a second thyristor forming a third closed circuit that is triggered by the charging voltage and causes the charged charge of the second capacitor to flow to the primary coil of the ignition coil, and the current flowing to the primary coil of the ignition coil. An engine ignition system characterized by an extended and doubled discharge current. 2 for the second thyristor of the third closed circuit, a second reverse diode, a second resistor, a second
2. The engine ignition system according to claim 1, wherein N stages of circuits each including a signal capacitor and a third thyristor are successively connected.