JPH0355818Y2 - - Google Patents

Description

[Detailed description of the invention] [Technical field of the invention] This invention is a capacitor charge/discharge type engine ignition system used for example in an internal combustion engine, and in particular, a capacitor charge/discharge type engine ignition system that improves the reliability of the engine stopping function. This relates to an ignition device.

[Prior art]

FIG. 1 shows the configuration of a conventional capacitor charge/discharge type engine ignition system. In the figure, 1 is a generator coil of a magnet generator of an internal combustion engine (not shown) installed as an AC power supply, 2 and 3 are diodes, 4 and 5 are first and second capacitors, and 6 is a thyristor. It has an anode a, a cathode c and a gate g. Diode 2 and first capacitor 4
are connected in series and connected to both ends of the generator coil 1. Reference numeral 7 denotes an ignition coil, which is composed of a primary coil 7a and a secondary coil 7b. The diode 3, the second capacitor 5, and the primary coil 7a are connected in series and connected to both ends of the diode 2. The thyristor 6 is connected in parallel to the series circuit of the second capacitor 5 and the primary coil 7a. 8 is an ignition plug, 9 is an ignition signal generator, and the ignition signal is output to the gate g of the thyristor 6. Reference numeral 10 denotes an engine stop switch, which is connected to the output end of the generator coil 1.

Next, the operation will be explained. First, when the voltage of the generating coil 1 is a negative half wave, a current flows in the order of the generating coil 1 -> the diode 2 -> the first capacitor 4 -> the generating coil 1, and the first capacitor 4 is charged to the illustrated polarity. Next, when the voltage of the generating coil 1 becomes a positive half wave, the generating coil 1 → the first capacitor 4
A current flows in the order of → diode 3 → second capacitor 5 → primary coil 7a of ignition coil 7 → generator coil 1, and the second capacitor 5
It is charged with the voltage of the sum of the output voltage of the first capacitor 4 and the charging voltage of the first capacitor 4 to the illustrated polarity. At this time, the thyristor 6 is brought into conduction by the ignition signal generator 9. When the ignition signal is input to and output from the thyristor g, the thyristor 6 star 6 becomes conductive, and the electric charge stored in the second capacitor 5 is transferred from the thyristor 6 to the ignition coil 7.
The primary coil 7a is rapidly discharged in the order of the second capacitor 5. At this time, a high voltage is generated in the secondary coil 7b due to the rapid current change in the primary coil 7a, causing a high voltage spark to fly to the ignition plug 8.

Here, in order to stop the engine, it is necessary to prevent high voltage from being generated in the secondary coil 7b of the ignition coil 7 and to prevent the ignition spark from flying to the ignition plug 8. In order to prevent high voltage from being generated in the secondary coil 7b, the output end of the generator coil 1 is grounded by the engine stop switch 10 so that the second capacitor 5 does not accumulate charge. Therefore, a method is generally used in which the first and second capacitors 4 and 5 are not charged.

The conventional engine ignition system is as described above, but as described above, when it is necessary to stop the engine, the output of the generating coil 1 is a positive half-wave, and the first capacitor is set to have a polarity opposite to the illustrated polarity. Since the generator coil 1 is charged in the direction, the engine stop switch 10
Along with the output current of the first capacitor 4, a discharge current due to the charge of the first capacitor 4 flows through the diode 2. The discharge current of the first capacitor 4 is excessive because the impedance of the discharge circuit is only the diode 2. Therefore, it is necessary to increase the rating of the diode 2 and also increase the rating of the engine stop switch 10. There is a need to.

This has the drawback of not only increasing the price but also significantly reducing the durability and reliability of the engine ignition system.

[Summary of the idea]

This idea was made to eliminate the above-mentioned drawbacks of conventional devices. When the engine is stopped, when the discharge current due to the charge in the first capacitor flows through the engine stop switch, it is discharged through the impedance circuit. To provide, at a low price, a capacitor charge/discharge type engine ignition system which has high durability and reliability without increasing the rating of the diode and engine stop switch by lowering the discharge current value. It is an object.

[Example of idea]

An embodiment of this invention will be described below with reference to FIG. In FIG. 2, reference numeral 11 denotes an engine stop switch, which is connected to the connection point between the first capacitor 4 and the diode 2.

The other configurations are similar to the conventional device shown in FIG. 1, and their explanation will be omitted.

Next, the operation of this embodiment will be explained. First, when the voltage of the generating coil 1 is a negative half wave, the generating coil 1
A current flows in the order of → diode 2 → first capacitor 4 → generator coil 1, and first capacitor 4 is charged to the illustrated polarity. Next, when the voltage of the generating coil 1 becomes a positive half wave, a current flows in the order of the generating coil 1 → the first capacitor 4 → the diode 3 → the second capacitor 5 → the primary coil 7a of the ignition coil 7 → the generating coil 1. Then, the second capacitor 5 connects to the generator coil 1.
It is charged with the voltage of the sum of the output voltage of the first capacitor 4 and the charging voltage of the first capacitor 4 to the illustrated polarity. When the second capacitor 5 is charged, an ignition signal is output from the ignition signal generator 9 to the gate g of the thyristor 6, and the thyristor 6 becomes conductive. When the thyristor 6 becomes conductive, the charge stored in the second capacitor 5 is transferred from the thyristor 6 to the primary coil 7 of the ignition coil 7.
A is rapidly discharged in the order of the second capacitor. At this time, due to the rapid current change in the primary coil 7a, a high voltage is generated in the secondary coil 7b, and the spark plug 8
emit high-voltage sparks.

Here, in order to stop the engine, when the engine stop switch 11 is grounded, when the voltage of the generator coil 1 is a negative half wave, a current flows in the order of the generator coil 1 → diode 2 → engine stop switch 11 → generator coil 1. . Next, when the voltage of the generating coil 1 becomes a positive half wave, a current flows in the order of the generating coil 1 -> the first capacitor 4 -> the engine stop switch 11 -> the generating coil 1.

As described above, when the engine stop switch 11 is grounded, both the positive and negative voltages of the generator coil 1 do not contribute to charging the second capacitor 5, and the ignition signal generator 9 signals the engine ignition timing. Even if the output is output to the gate g of the thyristor 6 and the thyristor 6 is turned on, there is no discharge current from the second capacitor 5, so no high voltage is generated in the secondary coil 7b of the ignition coil 7. Therefore, the engine stops.

Here, when the engine stop switch 11 is grounded, the discharge current of the first capacitor 4 flows through the generating coil 1 having an impedance.
The discharge current is not at a level that would degrade the first capacitor 4 and the engine stop switch 11 at all.

[Effects of the invention] After having described the above, in this invention, since the engine stop switch when the engine is stopped is configured to discharge the charge in the first capacitor via an impedance, The discharge current becomes extremely small, and the stress applied to the device is also reduced.

Therefore, by setting the rating of the element to be low, it is possible to reduce the price, and also improve durability and
A highly reliable capacitor charge/discharge type engine ignition system can be provided.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a conventional capacitor charge/discharge type engine ignition system, and FIG. 2 is a block diagram of a capacitor charge/discharge type engine ignition system according to an embodiment of this invention. In the figure, 1 is an AC power supply, 4 is a first capacitor,
5 is a second capacitor, 7 is an ignition coil, 9 is an ignition signal generator, and 10 and 11 are engine stop switches. In addition, in the figures, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A first capacitor charged by the half-wave output of the AC power supply, a second capacitor charged by the charging voltage of this capacitor and the reverse half-wave of the AC power supply, and a discharge current of this capacitor that controls the ignition voltage of the engine. A capacitor charging/discharging type engine ignition system comprising an ignition coil generated, and an engine stop switch that bypasses the charging voltage of the first capacitor and the reverse half wave of the AC power source via the AC power source.