JPH0110436Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an engine ignition system, particularly to an improvement in the signal section of a semiconductor switching element that controls the primary current of an ignition coil.

As a device of this kind, for example, in a device that uses the output voltage of the generating coil of a magnet generator as a power source, it has been proposed to use the output voltage in a direction that does not use the power source for driving the semiconductor switching element to ignite the generating coil. However, due to the armature reaction peculiar to magnet generators, the output voltage in the direction intended for ignition decreases, resulting in the inconvenience that a sufficient ignition function cannot be obtained.

This invention provides an engine ignition system that solves the above-mentioned disadvantages with a simple and inexpensive configuration.Hereinafter, a CD ignition system using a magnet generator as a power source will be described in detail as an example.

That is, in the figure, 1 is a generator coil of a magnet generator driven by the engine, and 2 is a generator that generates positive and negative ignition signal outputs shown by solid line a and broken line b in response to the rotation of the engine, that is, the engine ignition timing. This signal coil is usually built into a magnet generator. Furthermore, power generation coil 1
The output terminal of is connected to a series circuit of a diode 3, a capacitor 4, and a primary coil of an ignition coil 5. A diode 6 is connected in parallel to the primary coil of the ignition coil 5, and a thyristor 7, which is a semiconductor switching element, is connected in parallel to the capacitor 4 and the primary coil of the ignition coil 5. The collector-emitter of a transistor 11 is connected between the gate of the thyristor 7 and ground via a resistor 8 and a capacitor 9. transistor 11
The emitter of the transistor 13 is connected to the base of the transistor 13, and the transistor 15 is connected between the base of the transistor 13 and ground. A resistor 31 is connected between the base of the transistor 15 and ground, and one end of the signal coil 2 is connected to the base end via a resistor 16 and a diode 17. Furthermore, a diode 19 is connected antiparallel to the series circuit of the diode 17 register 16 register 31. Between the other end of the signal coil and the ground, a series circuit of a diode 24 and a capacitor 25 is connected via a first constant voltage circuit 20, and a diode 18 is connected in parallel with the opposite polarity to the series circuit of the diode 24 and capacitor 25. .
Furthermore, the capacitor 25 is connected to a second constant voltage circuit 2.
A capacitor 30 is connected in parallel via 6. A resistor 10 is connected to the non-grounded end of the capacitor 30.
The collector of transistor 11 is connected to the collector of transistor 13 through resistor 12, and the collector of transistor 13 is connected to
Furthermore, the collectors of transistors 15 are connected through resistors 14, respectively. The first constant voltage circuit 20 includes a thyristor 21 and this thyristor 2.
The second constant voltage circuit 26 consists of a constant voltage diode 22 connected between the anode and gate of the thyristor 21 and a resistor 23 connected between the gate and cathode of the thyristor 21. It consists of a resistor 28 connected and a constant voltage diode 29 connected between the base of a transistor 27 and ground. Further, an engine spark plug 32 is connected to the secondary coil of the ignition coil 5.

The operation of the embodiment configured as above will be described below. Now, when the AC output of the generator coil 1 is in the direction shown by the solid line c, the output voltage of the generator coil flows through the closed circuit of diode 3 - capacitor 4 - diode 6 and charges the capacitor 4 if the thyristor 7 is non-conductive. . The charge in the capacitor 4 is discharged through the primary coil of the ignition coil 5 due to conduction of the thyristor 7, and at this point a high voltage is induced in the secondary coil of the ignition coil 5, producing an ignition spark at the ignition plug 32. .

Now, to explain the operation for controlling the thyristor 7 in response to the engine ignition timing, first, when the AC output of the signal coil 2 is in the direction shown by the solid line a, the output of the signal coil 2 is Constant voltage circuit 20 - diode 24 - capacitor 25 -
Flows through the closed circuit of diode 19 and connects to capacitor 25.
to charge. The charge in the capacitor 25 is transferred to the registers 10, 12, 1 via the second constant voltage circuit 26.
4 (point X), transistors 11 and 13 are conductive and transistor 15 is non-conductive. Here, if the AC output of the signal coil 2 is in the direction shown by the broken line b in response to the ignition timing of the engine, the output flows through the closed circuit of the diode 17 - resistor 16 - resistor 31 - diode 18 and is output in the direction of the broken line b. The output voltage obtained by dividing the voltage into the register 16 and the register 31 is applied to the base of the transistor 15, and as a result, the transistor 15 becomes conductive. When the transistor 15 becomes conductive, the transistors 13 and 11 become non-conductive, and the collector of the transistor 11 becomes a high voltage, so that the capacitor 9
Charging current flows into. This charging current flows into the gate electrode of the thyristor 7 and reverses the thyristor 7 from a non-conducting state to a conducting state, so that the charge charged in the capacitor 4 is released as described above, and a high voltage is induced in the secondary coil of the ignition coil 5. Incidentally, the charge in the capacitor 9 is discharged via the transistor 11 and the resistor 8 when the transistor 11 becomes conductive again.

However, the control circuit from the transistor 15 receiving the output of the signal coil 2 to the gate pole of the thyristor 7 is connected to the power supply voltage, that is, the registers 10, 12, 14.
The operating characteristics of the thyristor 7 vary depending on the voltage between the common connection point X and the ground, making the conduction timing (ignition timing) of the thyristor 7 unstable. this is,
This is because the operating level of the transistor 15 that responds to the AC output of the signal coil 2 in the direction indicated by the broken line b and the time delay from when the transistor 15 responds to when the thyristor 7 becomes conductive vary depending on the power supply voltage. . However, since the supply source of the power supply voltage is the AC output of the signal coil 2 in the direction shown by the solid line a, the voltage value naturally fluctuates considerably, and since the phase of the signal output and the power supply are different during operation, the power supply is directly connected to the power supply. If you do so, the control circuit will not operate stably,
Therefore, as in the embodiment of the present invention, the power supply must be stabilized through the first and second constant voltage circuits 20 and 26. As is clear from the above circuit configuration, the first constant voltage circuit 20 operates in a nonlinear (digital) manner, and the second constant voltage circuit 26 operates in a linear (analog manner). Now, in the first constant voltage circuit 20, when the output voltage in the direction of the solid line a of the signal coil 2 reaches a first predetermined voltage value determined by the constant voltage diode 22, the thyristor 21 conducts and the subsequent signal coils 2
The output in the direction of the solid line a is bypassed, and therefore the capacitor 25 is charged until it reaches the first predetermined voltage. Therefore, when the AC output of the signal coil 2 is reversed in the direction of the broken line b and the signal output is input to the transistor 15, it is reversed again and the transistor 25 is charged. The thyristor 21 is non-conductive until reaching the predetermined voltage, but becomes conductive again after reaching the predetermined voltage.

The second constant voltage circuit 26 is connected to the solid line a of the signal coil 2.
Capacitor 25 charged by the output voltage in the direction
Since the circuit configuration is such that a transistor 27 is inserted in series between the control circuit of the registers 10, 12, 14 and the transistors 11, 13, 15, which are loads, the charging voltage of the capacitor 25 is determined by the voltage regulator diode 29. is less than a predetermined value (which is lower than the first predetermined value), the transistor 27
is in a fully conductive state, but when the voltage of the capacitor 25 rises to a second predetermined voltage or higher, the remaining voltage obtained by subtracting the second predetermined voltage from the charging voltage of the capacitor 25 is borne by the transistor 27, that is, the collector-emitter Since the power is dissipated as a voltage drop between them, the power supply voltage at point X is controlled to be constant at the second predetermined voltage. In this manner, in this embodiment, even if the output voltage of the signal coil 2 fluctuates due to the rotation of the engine, the power supply voltage at point X can always be maintained at a stable characteristic. Here, the first constant voltage circuit 20 stabilizes the pulsating current that has a large voltage change (generally 0 to 100 V) of the signal coil 2 to a pulsating current that has a voltage change of about 1/4 (0 to 25 V). is rectified by the diode 24, and the capacitor 25 is charged. Next, in the second constant voltage circuit, a direct current voltage (constant voltage) that can be used in actual use is
It stabilizes it to the extent of.

The capacitor 30 is inserted to absorb surge voltage contained in the output of the second constant voltage circuit 26.

In the above embodiment, the first and second constant voltage circuits 20 and 26 are provided, but either one may be used, and the same effect can be obtained even if other circuit configurations are used. Furthermore, it can be applied not only to CD ignition devices but also to AC ignition devices and other ignition devices.

As mentioned above, this invention uses the output of the signal coil in one direction as the ignition signal for the ignition device, and the output in the other direction is used as the power source for the control circuit of the ignition device via the constant power circuit, so it is stable. Good ignition performance such as accurate ignition timing can be obtained, and there is also the advantage that a separate power source such as a battery is not required as a power source for the control circuit of the ignition device.

[Brief explanation of the drawing]

The figure is an electrical circuit diagram showing an embodiment of this invention. In the figure, 1 is a power generation coil, 2 is a signal coil,
3, 6, 17, 18, 19, 24 are diodes,
4 is a capacitor, 5 is an ignition coil, 7 is a thyristor, 8, 10, 12, 14, 16, 23, 28,
31 is a register, 11, 13, 15, 27 are transistors, 20 is a first constant voltage circuit, 26 is a second
21 is a thyristor, 27 is a transistor, and 22 and 29 are constant voltage diodes.

Claims (1)

[Claims for Utility Model Registration] (1) A semiconductor switching element that controls the primary current of the ignition coil to induce an ignition voltage, a signal coil that generates positive and negative signal outputs in synchronization with engine rotation, and a signal coil that generates positive and negative signal outputs in synchronization with engine rotation. a constant power supply circuit that receives positive and negative signal outputs in one direction and generates a constant output; and operates in response to positive and negative signal outputs in the other direction,
An engine ignition system comprising an ignition timing determining circuit that applies a constant output of the constant power supply circuit to the semiconductor switching element to operate it. (2) The constant power supply circuit includes a nonlinear constant power supply section that exhibits nonlinear operation in response to the unidirectional output of positive and negative signal outputs from the signal coil, and a linear constant power supply section that exhibits linear operation in response to the output of this nonlinear constant power supply section. An engine ignition system according to claim 1, characterized in that the engine ignition system comprises: