JPS5941338Y2 - internal combustion engine ignition system - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement in an internal combustion engine ignition system, particularly in an internal combustion engine ignition system that uses a generating coil of a magnet generator as a power source.

First, the conventional example shown in FIGS. 1 and 2 will be explained.
In the figure, 1 is a magnet generator, 1a is a flywheel rotated by the engine, 1b and 1C are flywheels 1
Permanent magnet 1b is magnetized in the radial direction by two permanent magnets and a pole each installed at equal intervals inside a.
Further, the pole 1c is not magnetized.

1d is a generator iron core installed on the base of the magnet generator 10 (not shown), and its pair of pole faces are connected to the permanent magnet 1b and the pole 1.
c through a gap.

1e is the primary coil 1 of the ignition coil wound around this iron core 1d.
A generator coil that also serves as a coil generates alternating current output, that is, output in one direction (a shown by a solid line) and output in the other direction (b shown by a broken line) with mutually different polarities.

1f is a secondary coil of the ignition coil similarly wound around the iron core 1d; 2 is a first transistor which is a switching element that generates an ignition voltage by intermittent current flow in the a direction of the generator coil 1e; 3; is a second transistor that controls on/off of the first transistor 2; 4 is a resistor for causing the base current to flow through the first transistor 2; 5°6 is the operating point of the second transistor 3; The voltage dividing registers 1 and 8 for determining are resistors and diodes connected in series to both ends of the generating coil 1e, and form a series circuit that bypasses the b-direction output of the generating coil 1e that is not energized by the first transistor 2. Configure.

Next, this operation will be explained using a two-cycle engine as an example.

The generator coil 1e installed in the magnet generator 1, which rotates in synchronization with the internal combustion engine, generates an alternating current output as shown by the solid line a and the dotted line, and the output voltage is as shown by the dashed-dotted line in Fig. 3. Change.

Now, at the ignition timing of the engine, when a dog voltage A is generated in the direction of the generating coil 1eKa, the base current flows through the resistor 4 in the first transistor 2, and the transistor 2 is turned on, and current flows in the direction a of the generating coil 1e. are shorted through the first transistor 2.

Then, when the ignition timing of the engine comes and the terminal voltage of the register 6 divided by the voltage dividing registers 5 and 6 rises to a predetermined value, the base current flows through the second transistor 3 and the second transistor 3 is reversed from OFF to ON state. The base current of the first transistor 20 flowing through the resistor 4 is bypassed through the second transistor 3, so that the first transistor 2 is abruptly reversed to the off state and the generator coil 1e is turned off.
Cuts off current flow.

This rapid current change generates an ignition voltage in the secondary coil 1f, and in response to this ignition voltage, a spark plug (not shown) discharges a spark.

Next, when a b-direction output that is not used for ignition is generated in the generator coil 1e, this b-direction output is bypassed by a series circuit consisting of a resistor 7 and a diode 8 that are connected in parallel on both sides of the generator coil 1e. , the current indicated by the diagonal line in FIG.

Here, a occurs at both ends of the generating coil 1e.

Considering the output in direction b, as described above, an AC output of 2+j cycles is generated in the generator coil 1e for one revolution of the engine, and is used for ignition.

An ignition voltage is generated in the secondary coil 1f at a voltage A corresponding to the engine ignition timing among the outputs in the a direction, and no ignition voltage is generated at other small voltages.

Further, the b-direction output that is not used for ignition is bypassed by a DC circuit consisting of a resistor 7 and a diode 8, and is eventually suppressed from the one-dot-dashed line voltage port, H value, to the solid line voltage value.

By the way, in a series circuit including the resistor 7 and the diode 8, that is, when the load is not connected to the generator coil 1e, a large voltage aperture shown by the dashed line in FIG. The coil 1f has a voltage of 2 which corresponds to the change in the voltage of the generator coil 1e (shown by the dashed line).
The next voltage is induced, causing unnecessary sparks to fly to the spark plug at times other than the normal ignition timing, that is, before and after the ignition timing.

In particular, if an unnecessary spark occurs before the engine ignition timing, that is, during the engine intake and compression process, the gas in the cylinder will burn due to the low compression, which will not only adversely affect the engine, but also cause engine damage. There is a defect that makes it impossible to drive.

Therefore, a series circuit consisting of a resistor I and a diode 8 is connected to both ends of the generator coil 1e, and the b-direction voltage that occurs before the normal ignition timing is suppressed to a small voltage that does not cause sparks to fly to the spark plug. We try not to have a negative impact on the institution.

However, in this case, the b-direction voltage port of the generator coil/ie, c, causes the resistor 7 to pass the current shown in the shaded area in Figure 3 (■), consuming heat and suppressing the voltage to the solid line. Since the heat generation of the resistor 1 becomes extremely large and the resistor T also becomes large, the unit to be housed together with the transistor 2, 3, etc. that absorbs the ignition circuit becomes extremely large.

Furthermore, there is a risk that other elements may be destroyed due to the heat generated by resistor I. To solve this problem, resistor 7 with good heat dissipation is used.
There are issues such as the selection of the mounting position of the unit and the need for a heat dissipation structure for the unit.

This idea was made to eliminate the above defects.
The output of the other direction polarity of the generator coil that occurs before the ignition timing of the engine is consumed by the register and suppressed to a small value, while the output that has a particularly large output value among the outputs of the other direction polarity that occurs after the ignition timing is By controlling the semiconductor switching element to be in the on state and bypassing the output of the other polarity with a large output value to eliminate consumption by the register, it is possible to prevent unnecessary sparks from occurring before the ignition timing and to reduce the need for the resistor. This is an internal combustion engine ignition device that can reduce heat generation.

An embodiment of this invention will be described below with reference to FIG.

In the figure, 9 is a thyristor which is a semiconductor switching element connected in parallel to a series circuit of a diode 8 and a resistor 7 so that the current flows in the same direction. A diode and a resistor forming a circuit that charges the capacitor 12 with voltage;
Reference numeral 14 denotes a resistor for applying the charging voltage of the capacitor 12 as a gate signal to the thyristor 9 for a predetermined period.

Next, to explain the operation, since the ignition operation is the same as that in FIG. 1, it will be omitted, and the control operation of the b-direction output of the generator coil 1e will be described in detail with reference to FIGS.

First, the b-direction output generated before the ignition timing is bypassed by the resistor I and the diode 8, and the current shown in the shaded area in FIG. As shown, the voltage is suppressed to a value so small that no unnecessary high voltage is generated in the secondary coil 1f.

Next, to explain the suppression control of the b-direction output that occurs after the ignition timing, here, before the b-direction output is generated, the first transistor 2 intermittents the a-direction output, so that the power is applied to both ends of the generator coil 1e. A high voltage is generated in the a direction, and the capacitor 13 is charged to the polarity shown through the series circuit of the diode 12, resistor 11, and diode 10 in response to the induced discharge pressure (shown in Figure 3-2) based on this high voltage. ing.

Therefore, at point A in Figure 3 after the ignition timing, the generator coil 1
When the eKb force direction output is generated, the thyristor 9 is turned on for discharging the charge in the capacitor 13 through a discharge circuit consisting of the gate and cathode of the thyristor 9 and the resistor 14, and this thyristor 9 receives a predetermined gate signal. period is given.

This predetermined period is determined by the time constant of the capacitor v13 and the register 14.

When the thyristor 9 is turned on, the b-direction output of the generator coil 1e that attempts to energize the resistor T and diode 8 is bypassed by the thyristor 9 without energizing the resistor 7, and is sent to the thyristor 9 as shown in FIG. A short-circuit current shown by the solid line is applied, and the voltage across the generator coil 1e becomes the voltage drop of the thyristor 9 and has a small value.

As described above, the thyristor 9 reliably prevents the b-direction output from being energized to the resistor 7 after the ignition timing, and as a result, there is no heat consumption in the resistor I after the ignition timing.

Therefore, the electric current flowing to the resistor 7 is reduced only before the ignition timing, and the heat generated by the resistor 7 can be made extremely small without generating unnecessary sparks. No countermeasures are required.

In the above embodiment, the thyristor 9 is configured to short-circuit the b-direction output of the generator coil 1e, but due to the armature reaction of the generator coil 1e, the short-circuit current in the b-direction is used for ignition.

If the a-direction output is affected, it is also possible to connect a resistor 15 shown by a dotted line in series with the thyristor 9 to adjust the a-direction output to the extent that it does not affect the a-direction output.

In addition, in this embodiment, a transistor is used to interrupt the current flowing through the generator coil 1e, but a mechanical interrupter may also be used, and the generator coil 1e is an independent coil that does not also serve as the primary coil of the ignition coil. It is also possible.

Further, the thyristor 9 may be replaced with another semiconductor switching element such as a transistor.Furthermore, although the description has been made for a two-cycle engine, the same effect can be obtained even when applied to a four-cycle engine.

As described above, according to this invention, the resistor, which is used to ignite the generating coil and suppresses the output of the external polarity, is energized before the ignition timing, and after the ignition timing, the semiconductor switching element is used to conduct the bypass This configuration reliably prevents the generation of unnecessary sparks before the ignition timing, allowing the engine to be ignited appropriately.In addition, among the outputs of the other direction polarity of the generator coil after the ignition timing, outputs with larger output values are registered. Since no current is applied to the resistor, the heat generation of the resistor can be significantly reduced, which is a significant practical effect.

[Brief explanation of the drawing]

Fig. 1 is a configuration diagram of a magnet generator, Fig. 2 is an ignition circuit diagram showing a conventional device, Fig. 3 I is a voltage waveform diagram of the generating coil 1e, ■ is a current waveform diagram of the generating coil 1e, and Fig. 4 The figure is an ignition circuit diagram showing one embodiment of this invention. In the figure, 1e is a power generation coil, 1f is a secondary coil, 2
, 3 is a transistor, 4, 5, 6, 7°11.14.1
5 is a register, 8, 10.12 are diodes, and 9 is a thyristor. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A power generating coil that generates alternating current outputs of different magnitudes of one rotation Vcl cycle or more in synchronization with the rotation of the engine, and a unidirectional polarity output with a large output value among the alternating current outputs generated in this power generating coil is used as the engine ignition timing. A switching element that controls and generates a high voltage in the secondary coil of the ignition coil, a shunting resistor connected to be able to shunt the output in the other direction among the alternating current outputs generated in the generator coil, and this shunt resistor. A semiconductor switching element connected in parallel to a resistor, a capacitor that controls on/off of the semiconductor switching element, and a unidirectional polarity output having a larger output value among the alternating current outputs generated in the generator coil to charge the capacitor. charging circuit;
after the engine ignition timing, a discharging resistor receives the output generated in the generating coil and supplies the charging voltage of the capacitor as an operation signal to turn on the semiconductor element for a predetermined period; An internal combustion engine ignition device comprising a control circuit that bypasses an output having a large output value among the outputs of the other direction polarity that can be bypassed.