JPH0343423Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a device for stopping an internal combustion engine.

Prior Art In equipment that emphasizes ease of operation, such as agricultural machinery and small engine generators, a magnet generator is constantly connected to the ignition circuit of the internal combustion engine without using a key switch, and a rope start or kick start is used. It is ready to start immediately.
If the ignition circuit is connected to a power source at all times in this way, special measures must be taken to stop the engine. Figure 1 shows an example in which the stop device proposed earlier by the present applicant (Utility Model Application No. 126187/1987) is applied to an engine using a capacitor discharge type ignition system. grounded 1
The ignition coil 2 has a primary coil 1a and a secondary coil 1b, and 2 is a spark plug attached to a cylinder of an engine (not shown) and connected in parallel to both ends of the secondary coil. Reference numeral 3 denotes an ignition energy storage capacitor whose one end is connected to the non-grounded terminal of the primary coil 1a, and thyristors for capacitor discharge control with cathodes facing the grounding side are installed at both ends of the series circuit between the capacitor and the primary coil. 4 are connected in parallel.
The cathode of a diode 5 is connected to the connection point between the thyristor 4 and the capacitor 3, and the other end of an exciter coil 5 serving as an ignition power supply coil whose one end is grounded is connected to the anode of the diode 5. The above-mentioned parts constitute a capacitor discharge type ignition device.

In this ignition system, the exciter coil 6 is placed in a magnet generator (not shown) driven by the engine, and generates an alternating current voltage in synchronization with the rotation of the engine. When the exciter coil 6 generates a voltage in the direction of the arrow shown in the figure, the capacitor 3 is charged through the diode 5 to the polarity shown. Next, when a firing signal is applied to the thyristor 4 from a signal coil (not shown), the thyristor becomes conductive, and the charge in the capacitor 3 is discharged through the thyristor 4 to the primary coil 1a. This causes a large magnetic flux change in the iron core of the ignition coil, and a high voltage is generated in the secondary coil.
Therefore, a spark is produced in the spark plug 2, and the engine is ignited.

In order to stop the engine, an engine stopping thyristor 7 is connected in parallel to the exciter coil 6, and one end of an engine stopping capacitor 9 is connected to the gate of the thyristor 7 via a resistor 8 as current limiting means. There is. The other end of the engine stop capacitor 9 is connected to the cathode (ground) of the thyristor 7, and the cathode of a diode 10 is connected to the connection point between the capacitor 9 and the resistor 8. The anode of the diode 10 is connected to one end of a stop command switch 11, and the other end of the switch 11 is connected to the non-ground terminal of the exciter coil 6. The diode 10 above constitutes an initial charging circuit that charges the capacitor 9 from the exciter coil (power supply coil) side when the stop command switch is closed, and this circuit, the thyristor 7, the resistor 8, and the capacitor 9 stop the internal combustion engine. A device 12 is configured.

When the switch 11 is closed in the above-mentioned stop device, when a voltage having the polarity in the direction of the arrow shown in the figure is generated in the exciter coil 6, the capacitor 9 is charged through the diode 10 to the polarity shown in the figure. When charging of the capacitor 9 is completed, an ignition signal is applied to the thyristor 7 through the resistor 8 and the thyristor 7 becomes conductive, so that the exciter coil 6 is short-circuited through the thyristor 7. Therefore capacitor 3
This prevents the engine from charging and prevents ignition, causing the engine to misfire and slow down. Thyristor 7
When conductive, the voltage drop between the gate and cathode of the thyristor charges the capacitor 9 through the resistor 8 to the polarity shown. Capacitor 9 is thyristor 7
When the voltage between the gate and cathode of 1 exceeds the peak, discharge starts through the resistor 8. The discharge time constant of this capacitor is set so that after the exciter coil 6 generates an output for a half cycle in the direction opposite to the illustrated arrow, the discharge continues until the output for the next half cycle rises. Therefore, when an output in the direction of the arrow shown in the figure is generated in the exciter coil, an ignition signal is applied to the thyristor 7 and the thyristor becomes conductive. The conduction of the thyristor 7 charges the capacitor 9 again, and the above-described operation is repeated. Therefore, while the engine is rotating and a voltage is induced in the exciter coil, the thyristor 7 repeatedly conducts during the half cycle of the exciter coil in the direction of the arrow shown in the figure (the half cycle that contributes to the ignition operation) and short-circuits the exciter coil. Then, the ignition is blocked and the engine is stopped.

According to the above-mentioned engine stop device, since a self-resetting switch can be used as the switch 11, the stop device does not operate again when the engine is restarted, and there is no problem in starting the engine. . However, in the above device, it is necessary to sustain the discharge of the engine stop capacitor 9 for a half cycle in the direction opposite to the direction of the arrow shown in the figure of the exciter coil, so it is necessary to increase the discharge time constant of the capacitor. Therefore, it is necessary to increase the resistance value of the resistor 8. Therefore, it is not possible to increase the charging voltage when charging the capacitor 9 due to the voltage between the gate and cathode of the thyristor 7, and in order to ensure the discharge duration of the capacitor 9, it is necessary to increase the capacitance of the capacitor. It was hot. In addition, in this type of device, when the switch 11 is closed to stop the engine, it is preferable to display that the stopping operation is being performed in order to confirm that the operation of the stopping device has started. However, the conventional device described above could not perform this display.

Purpose of the invention The purpose of the invention is to make it possible to charge the engine stop capacitor to a sufficiently high voltage, thereby reducing the capacitance of the capacitor, and to make it possible to reduce the capacitance of the capacitor while the engine stop operation is being performed. An object of the present invention is to provide an internal combustion engine stopping device which can also display a display.

Structure of the Invention The present invention provides an engine stopping thyristor connected in parallel to a power coil of an ignition device for an internal combustion engine, and a gate cathode of the thyristor connected through a current limiting element. a stop command switch that is closed when the internal combustion engine is stopped; and an initial charge that charges the capacitor from the power supply coil side when the stop command switch is closed. In the present invention, a light emitting diode with an anode facing toward the gate of the thyristor is connected in parallel to both ends of the current limiting element.

With the above configuration, the engine stop capacitor is instantly charged via the light emitting diode by the voltage between the gate and cathode of the thyristor when the engine stop thyristor becomes conductive, so that the capacitor is always charged almost at the gate of the thyristor. Charged to cathode voltage. Therefore, a capacitor with a small capacity can be used as an engine stop capacitor,
Cost reduction can be achieved. Furthermore, when the engine stop thyristor is conductive and the engine stop capacitor is being charged by the voltage between the gate and cathode of the thyristor, the light emitting diode emits light, indicating that the engine stop operation is being performed. be able to.

Embodiments Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

Fig. 2 shows an embodiment in which the present invention is applied to a stop device of the type shown in Fig. 1. In Fig. 2, parts equivalent to those in Fig. 1 are designated with the same reference numerals. There is. In this embodiment, a resistor 14 having a sufficiently small resistance value is inserted between the cathode of the engine stop thyristor 7 and the ground, and a resistor 15 is connected in parallel to both ends of the series circuit of the diode 10 and the engine stop capacitor 9. There is. In the present invention, a light emitting diode 16 whose anode is directed toward the gate of the thyristor 7 is connected in parallel to both ends of the resistor 8 as a current limiting element. Others are 1st
It is constructed similarly to the device shown in the figure.

In the embodiment described above, the ignition operation is similar to the device of FIG. When the switch 11 is closed to stop the engine, when a voltage is generated in the exciter coil 6 in the direction of the arrow shown in the drawing, the capacitor is charged through the exciter coil 6-diode 10-capacitor 9-exciter coil 6 path.
When the output voltage of the exciter coil in the direction of the arrow passes the peak, the charge in the capacitor 9 is discharged between the resistor 8 and the gate cathode of the thyristor 7 and through the resistor 14, so that an ignition signal is given to the thyristor 7. Thyristor 7 is therefore conductive and exciter coil 6 is essentially short-circuited through thyristor 7 and resistor 14. This prevents the capacitor 3 from charging, causing the engine to misfire. Thyristor 7
When conductive, the capacitor 9 is charged to the illustrated polarity through the light emitting diode 16 by the sum of the voltage drop between its gate and cathode and the voltage drop across the resistor 14. Since the resistance value of the resistor 14 is small and the charging time constant of the capacitor 9 is small, the capacitor 9 is charged to a high voltage approximately corresponding to the peak value of the gate-cathode voltage of the thyristor 7. Therefore, even if the capacitance of the capacitor 9 is made small, the discharge duration of the capacitor can be ensured. Furthermore, since the light emitting diode 16 emits light when a charging current is flowing to the capacitor 9 through the light emitting diode 16, it is possible to indicate that the stop operation is being performed.

It is also conceivable to connect the anode of the light emitting diode 16 to the connection point between the resistor 14 and the cathode of the thyristor 7 in FIG. however,
With this configuration, it is not possible to reduce the charging time constant of the capacitor 9 due to the gate-cathode voltage of the thyristor 7, so the capacitor 9 cannot be charged to a high voltage, and the capacitance of the capacitor 9 cannot be reduced. cannot be made smaller.
In the embodiment of FIG. 2 it is therefore necessary to connect the anode of diode 16 to the gate of thyristor 7.

FIG. 3 shows another embodiment of the present invention, in which the collector of an NPN transistor 17 is connected to the anode of the diode 10. The emitter of the transistor 17 is grounded, and a stop command switch 11 for a stop operation is connected in parallel between the base of the transistor 17 and the ground. Further, the anode of a diode 18 is connected to the other end of the exciter coil 6, one end of which is grounded, and a resistor 19 is connected between the cathode of the diode 18 and the collector of the transistor 17. Further, a resistor 20 is connected between the cathode of the diode 18 and the base of the transistor 17, and in this embodiment, the diode 18 and the transistor 1
7. Resistors 19, 20 and stop command switch 1
1 constitutes an initial charging circuit that charges the capacitor 9 from the power supply coil side when the stop command switch is closed. In this initial charging circuit, the diodes 10 and 18 and the resistor 19 constitute a coupling circuit that couples the connection point between the resistor (current limiting element) 8 and the capacitor 9 to the other end of the exciter coil 6. Further, the diode 18 and the resistor 20 constitute a base current supply circuit that supplies a base current from the exciter coil 6 to the transistor 17.

In the above embodiment, the ignition operation is similar to the device of FIG. When the stop command switch 11 is open, the exciter coil 6 is activated when a voltage in the direction of the arrow shown in the figure is generated in the exciter coil 6.
- Diode 18 - Resistor 20 - Transistor 17
A base current flows through the transistor 17 through the base emitter-exciter coil 6 path, and the transistor 17 becomes conductive. In this case, therefore, all the current flowing from the exciter coil 6 through the diode 18 and the resistor 19 flows through the transistor, and no charging of the capacitor 9 and no ignition signal being supplied to the thyristor 7 takes place. Therefore, at this time, the engine ignition is performed normally.

To stop the engine, switch 1 for stop command
When the transistor 1 is closed, the base and emitter of the transistor 17 are short-circuited, so that the transistor 17 cannot conduct. Therefore, when a voltage in the direction of the arrow shown in the figure is induced in the exciter coil 6, the diode 1
8, the capacitor 9 is charged through the resistor 19 and the diode 10, and at the same time a firing signal is applied to the gate of the thyristor 7 through the resistor 8. This makes the thyristor 7 conductive and the exciter coil 6 is essentially short-circuited through the thyristor 7 and the small resistor 14. Therefore, the capacitor 3 is no longer charged and the engine misfires. Thyristor 7
When conductive, the engine stop capacitor 9 is charged through the light emitting diode 16 by the sum of the voltage drop between the gate and cathode and the voltage drop across the resistor 14. In the present invention, a light emitting diode 16 is connected in parallel to the resistor 8 as a current limiting element, and the charging time constant of the capacitor 9 is very small. It is almost instantaneously charged to a voltage corresponding to the sum of the terminal voltage of the resistor 14. Therefore, even if a capacitor 9 with a small capacity (approximately 1/10 of a conventional capacitor) is used, the capacitor can be discharged for a sufficiently long time, and an inexpensive capacitor can be used. Furthermore, in the present invention, when the stop command switch 11 is open, the transistor 17 is conductive, and when the switch 11 is closed, the thyristor 7 is conductive and short-circuits the exciter coil 6. Between the collector and emitter of transistor 17 is (R1 + R2) × Igt (R1 and R2
(Igt is the resistance value of the resistors 8 and 14, respectively, and Igt is the gate current of the thyristor 7). Only a low voltage is applied. Therefore, an inexpensive transistor with a low breakdown voltage can be used as the transistor 17, and costs can be reduced. Furthermore, since one end of the stop command switch 11 can be grounded, the structure of the switch can be simplified. Note that in FIG. 3, the diode 18 is used to prevent the reverse voltage of the exciter coil from being applied to the transistor 17, but if the transistor 17 can withstand the reverse voltage of the exciter coil, this diode 18 is omitted. can do.

FIG. 4 shows another embodiment of the present invention.
In this embodiment, a thyristor 21 is used in place of the diode 10 shown in FIG. The thyristor 21 has its anode connected to the non-grounded terminal of the exciter coil, its cathode connected to the connection point between the capacitor 9 and the resistor 8, and its gate connected to the collector of the transistor 17. In this embodiment, when the switch 11 is open and the transistor 17 is in a conductive state during a half cycle of the exciter coil in the direction of the arrow in the figure, no firing signal is given to the thyristor 21, so the thyristor maintains its cut-off state. are doing.
Therefore, at this time, the capacitor 9 is not charged and no ignition signal is given to the thyristor 7, so that the engine is normally ignited. When the switch 11 is closed and the transistor 17 is no longer conductive during the half cycle of the exciter coil 6 in the direction of the arrow shown in the figure, an ignition signal is given to the thyristor 21 through the diode 18 and the resistor 19, and the ignition signal is applied from the exciter coil 6 to the thyristor 21. Capacitor 9 is instantly charged through 21. With this configuration, the resistor 1 as in the embodiment shown in FIG.
Since the charging time constant of the capacitor 9 can be made much smaller than when the capacitor 9 is charged through the capacitor 9, the capacitor 9 can be reliably charged just by closing the switch 11 for a short time, thereby ensuring reliable operation. I can do it.

FIG. 5 shows still another embodiment of the present invention, in which the positions of the capacitor 9 and resistor 8 are swapped and the direction of the diode 10 is reversed in the embodiment of FIG. A diode 22 with its anode facing the ground side is connected in parallel between the gate of No. 7 and the ground. In this embodiment, capacitor 9 is charged to the polarity shown through diodes 22 and 10 in the half cycle of exciter coil 1 in the direction opposite to the arrow shown when switch 11 is closed. Since the charge in this capacitor is discharged through the gate and cathode of the thyristor 7, an ignition signal is applied to the thyristor, and the thyristor 7 becomes conductive during a half cycle of the exciter coil in the direction of the arrow shown. Other operations are similar to the embodiment shown in FIG.

Although a capacitor discharge type ignition device is used in the above embodiment, the present invention can be similarly applied to cases where other types of ignition devices are used. For example, as shown in FIG. 6, a switch 26 such as a transistor is connected in parallel to the primary coil 1a of the ignition coil (which also serves as an ignition power supply coil) disposed in a magnet generator driven by the engine.
When a well-known current cut-off type ignition device is used, which performs ignition by connecting the switch 26 to the cut-off state from the conductive state during a half cycle of the voltage induced in the primary coil 1a in the direction of the arrow shown in the figure. The present invention can also be applied to.

Further, as shown in FIG. 7, a transistor 28 is connected to both ends of the exciter coil 6 via a diode 27.
The collector-emitter circuit is connected in parallel, a thyristor 29 is connected in series with the primary coil 1a, and the base of the transistor 28 and the anode of the thyristor 29 are coupled via a diode 30. The present invention can also be applied when an ignition device is used. In this ignition device, spark plugs 2 and 2' are connected between both ends of the secondary coil of the ignition coil and the ground, respectively, and these spark plugs are connected to two cylinders in which there is no problem even if sparks are generated at the same time, e.g. Each is attached to two cylinders such that one is in the ignition timing and the other is in the exhaust stroke. In the ignition system of FIG. 7, the output voltage of the exciter coil 6 in the direction of the arrow shown in the figure causes the primary coil 1a and
A base current is applied to transistor 28 through 0, causing it to conduct. Next, when a firing signal is applied to the thyristor 29 from a signal coil (not shown), the thyristor becomes conductive and the transistor 28 is turned off. Therefore, from the exciter coil 6 to the diode 27 and the transistor 2
The current flowing through the exciter coil 6 is cut off, and a high voltage is induced in the exciter coil 6. This high voltage is further boosted by the ignition coil 1 and applied to the ignition plugs 2, 2', so that sparks are generated at both ignition plugs simultaneously.

In the above embodiment, the resistor 8 is used as the current limiting element, but a semiconductor element such as a diode with the cathode facing the gate of the thyristor 7 can also be used as the current limiting element.

In the above embodiment, the stop command switch 1
1 may be a manually operated switch such as a push button switch, or may be a detection switch that closes when the amount of oil in the engine becomes less than a specified amount.

Effects of the invention As described above, according to the invention, light emitting diodes with anodes facing toward the gate of the thyristor are connected in parallel to both ends of the current limiting element that couples the gate of the engine stop thyristor to the engine stop capacitor. As a result, the charging time constant of the engine stop capacitor by the voltage between the gate and cathode of the thyristor for engine stop has been reduced, so that the capacitor is charged to almost the peak value by the voltage between the gate and cathode of the thyristor, and the capacitor is It can be charged up to high voltage. Therefore, even if an inexpensive capacitor with a small capacity is used as the engine stop capacitor, the capacitor can be discharged for the required time, and the cost of the device can be reduced. In addition, in the present invention, a diode that works to reduce the charging time constant of the engine stop capacitor also serves as a light emitting display means.
Since the diode emits light when the engine stopping thyristor becomes conductive, there is an advantage that it is possible to display that a stopping operation is being performed with a simple configuration without providing a separate display element.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a conventional example, and FIGS. 2 to 7 are circuit diagrams showing different embodiments of the present invention. 1...Ignition coil, 2...Spark plug, 3...
Ignition energy storage capacitor, 4... Thyristor, 6... Exciter coil (ignition power supply coil), 7... Engine stop thyristor, 8... Resistor (current limiting element), 9... Engine stop capacitor,
11... Stop command switch, 10, 18... Diode, 12... Engine stop device, 16... Light emitting diode, 17... Transistor, 19, 20
...Resistance, 21...Thyristor.

Claims (1)

[Claims for Utility Model Registration] An engine stopping thyristor connected in parallel to a power supply coil of an ignition device for an internal combustion engine, and a gate cathode of the thyristor connected through a current limiting element between the thyristor and the gate cathode of the thyristor. An engine stop capacitor that is charged by a voltage drop across the cathode, a stop command switch that is closed when the internal combustion engine is stopped, and a stop command switch that charges the capacitor from the power supply coil side when the stop command switch is closed. An internal combustion engine stopping device comprising: a charging circuit, wherein light emitting diodes with anodes facing toward the gate of the thyristor are connected in parallel to both sides of the current limiting element.