JPH0318697Y2 - - Google Patents

Description

[Detailed description of the invention] [Field of industrial application] This invention relates to an ignition system for an engine.

[Conventional technology]

FIG. 3 shows a conventional ignition device disclosed in Japanese Utility Model Application No. 50-72821, Utility Model Publication No. 50-18021, Utility Model Publication No. 49-4501, etc. as this type of device. In the figure, 1 is a generator coil of a magnet motor driven by an engine (not shown), and 2 is a signal coil that generates an ignition signal at the ignition timing of the engine, and is built in, for example, a magnet generator. 3 is a diode that rectifies the generated output of the generating coil 1; 4 is a capacitor that is charged by the rectified output of this diode 3; 5 is a diode that short-circuits a half cycle of the generated output of the generating coil 1 that does not contribute to charging of the capacitor 4. , 6 is the ignition coil,
7 is a thyristor which is a semiconductor switching element that receives an ignition signal from the signal coil 2 at the engine ignition timing and discharges the charge in the capacitor 4 to the ignition coil 6; 8 receives a secondary voltage from the ignition coil 6 and discharges a sparkle; 9 is a diode that rectifies the ignition signal from the signal coil 2 and supplies it to the gate of the thyristor 7, and prevents reverse voltage from being applied between the gate and cathode; 10 is the generator coil 1;
A stop switch 11 is connected to both ends of the generator coil 1 and stops the engine by bypassing the generated output. 11 is connected to both ends of the generator coil 1, with the anode (input end) at the output end of the generator coil 1 and the stop switch 11 at the other end of the generator coil 1. A thyristor, which is a semiconductor switching element whose (ground side end) is connected to a cathode (output end);
12 and 13 are voltage dividing resistors connected in series to both ends of the generating coil 1, and a constant voltage diode 14, which is a constant voltage element, is connected to the connection point between the resistors 12 and 13 and the gate (control pole) of the thyristor 11. The cathode is connected to the connection point between the thyristor 12 and the resistor 13, and the anode is connected to the gate of the thyristor 11. The resistor 12, the resistor 13, and the constant voltage diode 14 constitute a voltage detection circuit.

Next, the operation will be explained. The power generation output of the power generation coil 1 is rectified by the diode 3 and charges the capacitor 4 . The half cycles that do not contribute to the charging of capacitor 4 are shorted by diode 5. The half-cycle output that contributes to charging the capacitor 4 of the generator coil 1 is divided by a resistor 12 and a resistor 13, and this voltage is compared with the Zener voltage of a constant voltage diode 14. When the divided voltage of the power generation output of the generating coil 1 divided by the resistors 12 and 13 exceeds the Zener voltage of the constant voltage diode 14, the constant voltage diode 14 becomes conductive and voltage is applied to the gate of the thyristor 11, causing the thyristor to close. 11
is conductive. Out of the generated output of the generating coil 1, the half cycle that contributes to charging the capacitor 4, that is, the output voltage of this half cycle is divided by the resistor 13, and when this voltage exceeds the Zener voltage of the constant voltage diode 14, the thyristor 11 is activated. Because it conducts,
Since the power generation output is limited to the power generation output voltage determined by the divided voltage determined by the resistors 12 and 13 and the Zener voltage determined by the constant voltage diode 14, the charging voltage of the capacitor 4 is limited to the power generation output voltage. Ru. Therefore, the charging voltage of the capacitor 4 does not become higher than necessary. The ignition signal generated in the signal coil 2 by the ignition timing of the engine is rectified by the diode 9 and applied to the gate of the thyristor 7, which becomes conductive.The charge in the capacitor 4 passes through the thyristor 7 to the primary coil of the ignition coil 6. is discharged. Then, a secondary voltage is generated in the secondary coil of the ignition coil 6, causing spark discharge at the ignition plug 8. The engine is operated in this way.

Further, in order to stop the engine in operation, it is sufficient to close the stop switch 10. That is, when the stop switch 10 is closed, the power generation output of the generating coil 1 is bypassed through the stop switch 10, so no electric charge is accumulated in the capacitor 4, and therefore no spark discharge occurs in the spark plug 8. ,
The engine will stop.

[Problem that the invention attempts to solve]

By the way, in this case, when the stop switch 10 is open, that is, when the engine is running, the generated output of the generator coil 1 (generally several hundred volts) is directly applied between the terminals of the stop switch 10 at all times. Therefore, although the stop switch 10 is insulated, if water, seawater, etc. are applied between the terminals of the stop switch 10, the insulation resistance between the terminals of the stop switch 10 will decrease, and the voltage applied between the terminals will be high. As a result, leakage current increases,
The current causes the stop switch 10 to malfunction, for example to cause dielectric breakdown, making it impossible to stop or restart the engine. Furthermore, even if this did not occur, the stop switch 10 would be exposed to water or seawater, resulting in an electric shock if the worker's hands were wet.

Another method is shown in Fig. 4 of Japanese Patent Publication No. 59-45836. In this figure, 1
5 is a thyristor which is a semiconductor switching element whose anode is connected to the output end of the generator coil 1 and whose cathode is connected to the anti-ground terminal of the stop switch 10, 16 is a diode connected between the cathode and gate of the thyristor 15, and 17 is a semiconductor switching element. A resistor 18 is connected between the output end of the generating coil 1 and the gate of the thyristor 15, and a constant voltage diode 18 is a constant voltage means connected between the gate of the thyristor 15 and the ground.The cathode of the constant voltage diode 18 and the resistor 17 The gate of the thyristor 15 and the cathode of the diode 16 are connected to the connection point. In this case, a constant voltage diode 18 was connected between the gate of the thyristor 15 and the other end of the generator coil 1 (the ground side in FIG. 2), and the voltage between the terminals of the stop switch 10 was always maintained at a low voltage. Although this method can prevent breakage of the stop switch and electric shock, it still has the disadvantage that it requires two thyristors 12 and 15 with high withstand voltage, making it expensive.

This idea was made to solve the above-mentioned problems, and it prevents damage to the stop switch 10 and electric shock, suppresses charging voltage higher than necessary, and also uses semiconductors that make up the stop circuit and the voltage suppression circuit. To obtain an inexpensive engine ignition device in which both of the switching elements do not require a high withstand voltage, and one can have a low withstand voltage.

[Means for solving problems]

The ignition device according to this invention includes a first semiconductor switching element connected to one end of the power generation coil of a magnet generator, and a stop switch connected to the output end of the first semiconductor switching element and the other end of the power generation coil. , the voltage applied to the control pole of the first semiconductor switching element is made constant by a constant voltage means, and a second semiconductor switching element is connected between the output terminal of the first semiconductor switching element and the other end of the generating coil. The control pole of this second semiconductor switching element is controlled by the output of the voltage detection circuit of the generating coil.

[Effect]

In this invention, since the control pole of the first semiconductor switching element is set to a constant voltage, both ends of the stop switch connected to the first semiconductor switching element are always maintained at a low voltage, and furthermore, the control pole of the first semiconductor switching element is kept at a low voltage. A low voltage withstand voltage element can be used as the second semiconductor switching element connected to the second semiconductor switching element, and since the second semiconductor switching element is controlled by the voltage detection circuit, the charging voltage can be suppressed to the required voltage.

[Example of idea]

An embodiment of this invention will be described below with reference to the drawings. In FIG. 1, reference numeral 19 denotes a thyristor which is a second semiconductor switching element connected between the cathode of the thyristor 15 and the other end (ground side end) of the generating coil 1, and the anode (input end) of this thyristor is the thyristor. 15 , the cathode (output end) is connected to the other end (ground side end) of the generator coil 1 , and the gate (control pole) is connected to the anode of the constant voltage diode 14 .

Next, the operation will be explained. First, when the stop switch 10 is opened, the generated output of the generator coil 1 is rectified by the diode 3, charges the capacitor 4, and is connected to the resistor 17 and the constant voltage diode 18.
and resistors 12 and 13 are energized. Here resistance 1
7 needs to have a relatively large value because only the current required to trigger the thyristor 18 needs to flow, and the resistor 12 needs to have a relatively large value because only the current needed to trigger the thyristor 19 needs to flow. Therefore, the current flowing through the resistor 17, the constant voltage diode 18, and the resistors 12 and 13 may be small, so that the load on the power generation output of the power generation coil can be reduced. Since the voltage dividing point between the resistor 17 and the constant voltage diode 18 is connected to the gate of the thyristor 15, the gate voltage (trigger voltage) of the thyristor 15 with respect to the ground becomes the voltage drop across the constant voltage diode 18. The cathode voltage of the thyristor 15 is
It is almost the same as the gate voltage. Therefore, the voltage between the terminals of the stop switch 10 is equal to that of the constant voltage diode 18.
The voltage will drop. Since the voltage drop of the constant voltage diode 18 can be freely selected from approximately 1.5 V or more to several tens of V, it can be set to a low voltage. Therefore, since the voltage between the terminals of the stop switch 10 is low, even if water or seawater were to adhere to the stop switch 10, the leakage current would be extremely small, so there would be no dielectric breakdown of the stop switch 10 or electric shock. Further, the output voltage of the generator coil 1 is divided by resistors 12 and 13 and compared with the Zener voltage of a constant voltage diode 14. When the voltage divided by the resistors 12 and 13 exceeds the Zener voltage of the voltage regulator diode 14, the voltage divided by the resistors 12 and 13 passes through the voltage regulator diode 14 and is applied to the gate of the thyristor 19. Conduct. When the thyristor 19 becomes conductive, a voltage drop determined by the constant voltage diode 18 is applied to the gate of the thyristor 15. Then, the thyristor 15 becomes conductive, and the power generation output of the power generating coil 1 is short-circuited through the thyristor 15 and the thyristor 19. Therefore, the generating coil 1
When the generated output voltage reaches the output voltage determined by the divided voltage determined by the resistors 12 and 13 and the Zener voltage of the constant voltage diode 14, the generated output of the generating coil 1 is short-circuited. Since the charging voltage of the capacitor 4 is determined by the generated output voltage of the generating coil 1, resistors 12 and 1 are connected to prevent excessive charging voltage.
3. By setting the constant voltage diode 14, the withstand voltage of the ignition coil can be suppressed to a necessary and sufficient voltage, and breakdown voltage defects due to excessive voltage can be eliminated. Furthermore, since the cathode voltage of the thyristor 15 is low, the thyristor 19 can be one with a low withstand voltage and can be inexpensive.

Next, when the engine is stopped, when the stop switch 10 is closed, the voltage drop of the constant voltage diode 18 is applied between the gate and cathode of the thyristor 15, and the thyristor 15 becomes conductive. As a result, the power generation output of the power generating coil 1 is short-circuited through the thyristor 15 and the stop switch 10, so after the stop switch 10 is closed, the capacitor 4 is no longer charged, so even if the thyristor 7 is conductive at the engine ignition timing, the ignition coil 6 is not charged. No secondary voltage is generated, so the engine will definitely stop.

In the above embodiment, the thyristor 19 is provided in the second semiconductor switching element, but the transistor 20 may be provided in the second semiconductor switching element as shown in FIG. It has the effect of

[Effect of idea]

As described above, according to this invention, the control pole of the first semiconductor switching element connected to the output end and the other end of the power generation coil is made constant voltage to a low voltage, and the output end of the first semiconductor switching element is A stop switch and a second semiconductor switching element are connected to the other end of the generator coil, and the control pole of the second semiconductor switching element is controlled by the output of a voltage detection circuit that detects the output voltage of the generator coil. Therefore, the voltage between the terminals of the stop switch can be lowered, the ignition voltage of the ignition device can be prevented from becoming overvoltage, and a highly reliable device can be obtained.Furthermore, the second semiconductor switching element can be an element with a low withstand voltage. This has the effect of making the device cheaper.

[Brief explanation of the drawing]

Figure 1 is a circuit diagram showing one embodiment of this invention, Figure 2 is a circuit diagram showing another embodiment of this invention, and Figure 3 is a circuit diagram showing another embodiment of this invention.
The figure is a circuit diagram showing a conventional ignition device, and FIG. 4 is a circuit diagram showing another conventional embodiment. In the figure, 1 is a generator coil, 2 is a signal coil, 3, 5, 9, 16 are diodes, 4 is a capacitor, 6 is an ignition coil, 7, 11, 15, 19 is a thyristor, 8 is a spark plug, and 10 is a stop switch. , 12, 13 and 17 are resistors, 14 and 18 are constant voltage diodes, and 20 is a transistor.
Note that the same reference numerals in the figures indicate the same or corresponding parts.

Claims (1)

[Scope of Claim for Utility Model Registration] (1) A generator coil of a magnet generator, an ignition circuit that receives the output of the generator coil and generates an engine ignition voltage in the ignition coil, and an input end connected to one of the generator coils and the other. a first semiconductor switching element,
a stop switch connected to the output end of the first semiconductor switching device and the other end of the power generation coil; a stop switch connected to the control pole of the first semiconductor switching device and the other end of the power generation coil; a constant voltage means for making the voltage applied to the control pole of the switching element constant; a second semiconductor switching element having an input end connected to the output end of the first semiconductor switching element and an output end connected to the other end of the generating coil; An ignition system for an engine comprising a semiconductor switching element and a voltage detection circuit that detects the power generation output of the power generation coil and controls a control pole of the second switching element. (2) The breakdown voltage of the second semiconductor switching element is the same as that of the first semiconductor switching element.
An ignition device for an engine according to claim (1) of the utility model registration, characterized in that the withstand voltage is lower than the withstand voltage of the switching element. (3) The engine ignition system according to claim (1), wherein the second semiconductor switching element is a thyristor. (4) The engine ignition system according to claim (1), wherein the second semiconductor switching element is a transistor.