JPS6140942Y2 - - Google Patents

Description

[Detailed explanation of the invention] This invention disables the ignition circuit that uses the output of the generator coil as the ignition source when the internal combustion engine's rotational speed reaches a predetermined value, thereby preventing the engine rotational speed from rising above a predetermined value. Regarding an internal combustion engine ignition device with a built-in rotation speed control circuit, in particular, the operation of the rotation speed control circuit,
It concerns an inoperative switching circuit.

For the sake of the organization's own security in the event of an abnormality,
In addition, for the safety of equipment connected to the engine, an internal combustion engine ignition system is used that has a built-in rotation speed control circuit that prevents the rotation speed from rising above a predetermined value, but the rotation speed control circuit does not operate all the time. , an active/inactive switching circuit is required so that it operates only in the event of an abnormality. Further, many of these engines do not have batteries, and the output of the generator is often used as a power source for the rotation speed control circuit.

Conventionally, there has been a switching circuit of this type as shown in FIG. In the figure, 1 is a generator driven by the engine, such as a generator coil of a well-known magnet generator, and 2 is a signal coil that generates an ignition signal output in response to engine ignition, which is attached to the above-mentioned magnet generator. , generates AC output in synchronization with engine rotation.
Reference numeral 3 denotes an ignition circuit of the well-known capacitor discharge type, current cutoff type, etc., which uses the output of the generator coil 1 as a power source, receives the output of the signal coil 2, and generates an ignition output for the engine. 4 is an ignition coil that receives the output of the ignition circuit 3 and generates high voltage on the secondary side; 5 is the ignition coil 2 of 4;
A spark plug receives the next voltage and discharges a spark; 6 is a diode that rectifies the power generation output of the signal coil 2; 7
is a frequency-voltage converter which receives the rectified output of the diode 6 and generates an output according to the engine speed, and is composed of a charging/discharging circuit including a capacitor and a resistor. 8 receives the output of the frequency-voltage converter 7;
This is a switch circuit that short-circuits the output of the generator coil 1 and disables the ignition circuit 3, and is composed of switching elements such as thyristors. 9 is a diode 10 that separates the rectified output of the diode 6 into the supply to the frequency-voltage converter 7 and the supply to the power supply circuit 14; 11 is a transistor; 112 is a constant voltage diode that serves as a reference voltage; and 13 is a constant voltage. a capacitor for smoothing the pulsating current included in the output of the voltage circuit; 14 is a power supply circuit configured as described above;
Reference numeral 15 denotes a switch that can be switched automatically or manually in the event of an abnormality, and opens and closes the connection between the frequency-voltage converter 7 and the switch circuit 8 to switch between operating and disabling the rotational speed control operation.

Next, the operation will be explained. It is assumed that the switch 15 is now closed. The power generation outputs of the power generation coil 1 and the signal coil 2 are supplied to the ignition circuit 3. For the ignition circuit 3, for example, a capacitor charge/discharge type ignition circuit or a transistor type ignition circuit is used. The ignition circuit 3 uses the output of the power generation coil 1 as an energy source for ignition sparks, receives the power generation output of the signal coil 2 at a predetermined ignition timing, and supplies energy to the ignition coil 4. A high voltage is generated on the next side and an ignition spark is generated at the ignition plug 5. Also, the output of signal coil 2 is connected to diode 6.
The signal is rectified by the voltage converter 7 and supplied to the frequency-voltage converter 7. The frequency-to-voltage converter 7 produces a rectified output of the signal coil 2, ie an output proportional to the rotational input signal. Further, since the frequency of the rotation input signal is proportional to the engine rotation speed, the output of the frequency-voltage converter 7 is proportional to the engine rotation speed.

The switch circuit 8 receives the output of the frequency-voltage converter 7, and becomes conductive when the output reaches a predetermined voltage. For example, it is composed of transistors, thyristors, etc. Therefore, when the engine speed increases and the output of the frequency-voltage converter 7 reaches a predetermined value, the switch circuit 8 becomes conductive and the output of the generator coil 1 is short-circuited. Therefore, the ignition circuit 3 is disabled and the ignition spark of the ignition plug 5 is extinguished. Therefore, when the engine speed decreases and the output of the frequency-voltage converter 7 becomes lower than a predetermined value, the switch circuit 8 becomes non-conductive and the ignition circuit 3 is activated again, causing an ignition spark from the spark plug 5. In this way, the engine speed is controlled to rise above a predetermined value.

Now, the rectified output of the diode 6 is supplied through a diode 9 and a resistor 10 to a constant voltage diode 12 which serves as a reference power source. Constant voltage diode 12
The reference power generated by is supplied to the base of transistor 11. Here, since the base-emitter voltage of transistor 11 is constant at approximately 0.6V, the emitter voltage of transistor 11 is - the reference power supply voltage.
It becomes constant at 0.6V, making it a constant voltage. The capacitor 13 is for smoothing the pulsating current included in the output of the constant voltage circuit.

The above is a case where the switch 15 is closed, but when it is open, no signal is supplied from the frequency-voltage converter 7 to the switch circuit 8, and therefore the switch circuit 8 maintains an open state. Rotation speed control operation is not performed.

The disadvantages of the above conventional devices are as follows: 1. In general, when the switch 15 breaks down, it is often left open, and there may be problems such as poor connection of the wiring to the switch 15, disconnection of the wiring, etc. Since there is a high possibility that the circuit will become open, the rotation speed control operation will not be performed in such a case, which is dangerous.

2. Rotation speed control The rotation speed is not only set to the maximum allowable rotation speed of the engine, but may also be set to lower the rotation speed to the engine's idling speed in the event of an abnormality. In this case, if the circuit constants are set so that the power supply circuit 14 supplies sufficiently stable power to the frequency-voltage converter 7 at low idling speed, the normal switch 1
5 is open and the engine is rotating at high speed, the voltage and current applied to the constant voltage diode 12 and the transistor 11 become large, and elements with high withstand power and high voltage are required.

In addition, a frequency-voltage converter 7, a power supply circuit 14
Since it operates even during high speed rotation, the load on the signal coil 2 becomes large and the ignition timing may fluctuate.

3. If the wiring to the switch 15 is long, the wiring is susceptible to noise, and this noise may cause the switch circuit 8 to malfunction. Further, in order to prevent malfunctions due to noise, noise is absorbed by a capacitor or the like, but this capacitor deteriorates the responsiveness of the rotation speed control operation.

Furthermore, in the conventional circuit shown in FIG. 2, the switch 15 is inserted between the switch circuit 8 and the generator coil 1, and although this circuit solves the above-mentioned drawback in item 3, Since a voltage of several hundred volts is applied to the switch 15, if seawater enters the switch 15, especially in an outboard motor, a leakage current will flow, which may cause the switch 15 to burn out.

Further, if the ignition circuit 3 is of a transistor type, a current of several amperes flows through the switch 15, so a switch with a large withstand current is required.

This idea was made to eliminate the drawbacks of the conventional ones as mentioned above, and by connecting the switching element in parallel with the reference power supply of the constant voltage circuit, it is safe and has less influence on other characteristics. The object of the present invention is to provide an operation/inoperation switching circuit for a rotation speed control circuit.

Hereinafter, embodiments of this invention will be described with reference to the drawings. In FIG. 3, reference numeral 16 denotes a reverse current prevention diode that breaks the base-emitter reverse breakdown voltage of the transistor 11 the moment the switch 15 closes and prevents the charge in the capacitor 13 from discharging and destroying the transistor 11. , the switch 15 is connected in parallel with a constant voltage diode 12 serving as a reference power source.

Next, the operation will be explained.

When the switch 15 is in the open state, the power supply circuit 14 operates normally and therefore performs rotation speed control operation. Next, when the switch 15 is closed, the reference power supply voltage becomes 0 volts, and therefore the output of the power supply circuit 14 becomes 0 volts.
volt, the frequency-voltage converter 7 does not operate, and the rotation speed control becomes inoperative.

In such a configuration, when the switch 15 is in the open state, the rotation speed control circuit 7 comes into operation, and even if the switch 15 is left open due to a failure or the like, the rotation speed control circuit remains operational and safe. Also, when the switch 15 is closed, the voltage regulator diode 1
No voltage is applied to the transistor 2, the transistor 11 becomes non-conductive and does not consume power, and the power supply circuit 14
Since the output is 0 volts, the frequency-voltage conversion circuit 7 does not consume power, and only the resistor 10 consumes power.

Therefore, the constant voltage diode 12 and the transistor 11 need only have low power resistance, and furthermore, the load on the signal coil 2 is lightened, and fluctuations in ignition timing are also reduced.

Further, since the voltage and current applied to the switch 15 are several tens of volts and several tens of milliamperes, it is possible to use a switch that is safe and has a small capacity even when used in an outboard motor or the like. Regarding noise,
Since noise is absorbed by the constant voltage diode 12 and transistor 13, there is no fear of malfunction and stable operation is performed.

In FIG. 3, a switch is used as the switching element connected in parallel with the reference power source, but the same operation can be achieved even if this is replaced with a semiconductor switch.

Figure 4 shows an example using a transistor switch with a delay in operation.
Only the parts corresponding to are shown. In the figure, 17 is a transistor switch corresponding to switch 5 in FIG. 3, 18 is a resistor, and 19 is an operation delay capacitor. When the switch 15 is open, no voltage is applied to the base of the transistor 17.
Therefore, the transistor 17 is in an open state, and the power supply circuit operates normally, thereby controlling the rotation speed. Next, when switch 15 is closed, a voltage is applied to the base of transistor 17, so that transistor 1
7 is in a closed state, the reference power supply voltage is 0 volts, and the output of the power supply circuit 14 is 0 volts. However, when the output of the power supply circuit 14 becomes 0 volts, the base voltage of the transistor 17 also becomes 0 volts, so the transistor 17 becomes open and the power supply circuit 1
The output will appear in 4. By repeating this state, the power supply circuit output voltage becomes stable at a certain value determined by the values of the resistors 18 and 10 and the DC current amplification factors of the transistors 11 and 17. By setting this voltage to a voltage sufficiently lower than the voltage at which the frequency-voltage converter 7 operates, the switch 15 can be used to switch the rotation speed control between operation and non-operation.If the voltage is sufficiently low, the circuit shown in FIG. It has the same effect as.
Furthermore, when the switch 15 is switched from the closed state to the open state, the current path to the base of the transistor 17 is cut off through the switch 15, but the capacitor 1
Since the charge stored in transistor 9 supplies current to the base of transistor 17, transistor 17 remains closed for a while. Therefore, the rotation speed control operation is delayed with respect to the operation of the switch 15.

Regarding this delay, in some cases it is better to have no delay, but in other cases a delay is necessary. For example, if the abnormality lasts for an extremely short period of time, if the engine can tolerate it, smoother operation can be achieved by not performing unnecessary rotation control operations. This can be solved by providing a delay as shown in FIG.

As described above, the present invention has great effects, such as eliminating the drawbacks of conventional devices and providing functions that could not be obtained with conventional devices when combined with a semiconductor switch.

[Brief explanation of drawings]

Figures 1 and 2 are electrical circuit diagrams showing conventional equipment;
FIG. 3 is an electrical circuit diagram showing an embodiment of this invention.
FIG. 4 is an electrical circuit diagram showing another embodiment of this invention. In the figure, 1 is a generator coil, 2 is a signal coil, 3 is an ignition circuit, 4 is an ignition coil, 5 is a spark plug, 6, 9, and 16 are diodes, and 7 is a frequency
A voltage conversion circuit, 8 is a switch circuit, 10 and 18 are resistors, 11 and 17 are transistors, 12 is a constant voltage diode, 13 and 19 are capacitors, 14 is a power supply circuit, and 15 is a switch. Note that the same reference numerals in each figure indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] An ignition circuit that uses the output of the generator coil as an ignition source; a signal coil that generates an output in synchronization with the rotation of the engine and uses this output as an ignition signal for the ignition circuit; A rotation speed control circuit generates an output according to the rotation speed, and when this output reaches a predetermined value, controls the ignition circuit to cause the engine to misfire and control the rotation speed. A constant voltage circuit having a constant voltage means for generating a voltage and serving as a power source for the rotation speed control circuit, and a switching element connected in parallel with the constant voltage means of the constant voltage circuit, By closing, the output voltage value of the above constant voltage circuit is switched,
An internal combustion engine ignition device characterized in that the rotation speed control circuit can be switched between operation and non-operation.