JPH0450460Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Field of Application] This invention relates to an internal combustion engine ignition system, particularly to an improvement in advance control.

[Conventional technology]

Figure 5 is a circuit diagram of a conventional internal combustion engine ignition system of the type described in, for example, Utility Model Publication No. 59-41345;
The figure shows voltage waveforms at various parts of the engine shown in Figure 5, and Figure 7 shows the advance angle characteristics of the engine shown in Figure 5. The ignition device will be explained.

In the figure, 1 is a generator coil for ignition provided in a magnet generator driven by an internal combustion engine, 2, 3
4 is a diode, 4 is a capacitor, 5 is a diode, 6 is an ignition coil, 601 is a primary winding of the ignition coil 6, 602 is a secondary winding, and 7 is a spark plug.

8 is an ignition signal coil provided in the magnet generator, 9 and 10 are diodes, 11 is a capacitor,
12 is a transistor, 13 is a thyristor,
Ignition circuit I for the ignition coil 6 by means of diodes 2, 3, capacitor 4 and thyristor 13
is formed.

Next, the operation will be explained. In addition, in FIG. 6, A is the output voltage Va of the ignition generator coil 1,
B is the output voltage Vb of the ignition signal coil 8, C is the voltage Vc at point A in Fig. 5, and D is the capacitor 4.
Charging voltage Vd, E is the secondary winding 6 of the ignition coil 6
02 voltage Ve is shown respectively.

The output voltage Va of the ignition generator coil 1 has the waveform shown in Fig. 6A, and in the positive half wave, it changes from 1→3→
Capacitor 4 is charged through the path 4→5→1.
The negative half-wave is short-circuited with diode 2. The output voltage Vb of the ignition signal coil 8 is out of phase with the output voltage Va by 90 degrees as shown in FIG. The capacitor 11 is charged. The negative half wave is blocked by diode 9 and does not flow.

In FIG. 6C, the solid line represents the voltage Vc ₁ at point A during high-speed rotation of the internal combustion engine, that is, the transistor 1
2, and the dash-dotted line shows the voltage Vc ₂ at point A during low speed rotation. Capacitor 11 is charged by voltage Vb and maintained at its maximum charging voltage. When the voltage Vb drops and the emitter-base voltage of the transistor 12 reaches a predetermined trigger level, for example 0.6V or higher, the transistor 12 becomes conductive and the capacitor 11
The charged charge flows from 11 → 12 → gate of thyristor 13 → cathode of thyristor 13 → 11,
Trigger thyristor 13. Due to this trigger, the charge on capacitor 4 changes from 4→13→60.
It flows along the path 1→4, induces a high voltage in the secondary winding 602 of the ignition coil 6, and causes the spark plug 7 to generate a spark. Output voltage of ignition signal coil 8,
In other words, the voltage Vc at point A is higher when the rotational speed of the internal combustion engine is high (Vc ₁ ) than when it is low (Vc ₂ ), as shown in FIG. That is, the ignition point of the spark plug 7 is such that the voltages Vc ₁ and Vc ₂ correspond to the trigger level of the transistor 12 from their peaks, for example.
When the voltage drops to a predetermined value such as 0.6V, the transistor 12 becomes conductive at time _T1 during high-speed rotation and at time _T2 during low-speed rotation, causing ignition. Therefore, as shown in FIG. 7, when the rotational speed of the internal combustion engine is low, the ignition timing is advanced as the rotational speed increases.

[Problem that the invention attempts to solve]

Some types of internal combustion engines, such as two-stroke engines for outboard motors, are required to have lag characteristics at low speeds as the rotational speed increases, or to have almost constant flat characteristics. As mentioned above, the internal combustion engine ignition system has a lead characteristic when rotating at low speeds, so there is a problem in that it cannot satisfactorily meet the above-mentioned requirements.

This invention was made to solve the problems of the conventional ones, and it has a flat characteristic in which the ignition timing is almost constant, or an internal combustion engine ignition characteristic in which the ignition timing is delayed as the rotational speed increases when the internal combustion engine rotates at low speed. The purpose is to provide a device.

[Means for solving problems]

The internal combustion engine ignition device according to this invention connects a constant voltage power source and an ignition signal coil in parallel, and
a first electrical switch connected to the parallel connection point and held in a predetermined open/close state when the output voltage of the ignition signal coil drops to a predetermined level with respect to the constant voltage output of the constant voltage power supply; a second electric switch connected to the first electric switch and held in an open/closed state opposite to that of the first electric switch; The ignition signal generation circuit includes a capacitor that is charged and generates an ignition signal based on a predetermined open/closed state of the second electric switch, and an ignition circuit that performs an ignition operation based on the ignition signal of the ignition signal generation circuit. It is something.

[Effect]

In this invention, when the output voltage of the ignition signal coil drops to a predetermined level with respect to the constant voltage output of the constant voltage power supply, the second electric switch enters a predetermined open/close state to charge the capacitor and ignite. Since the signal is generated, while the rotational speed of the internal combustion engine is low, that is, while the output voltage of the ignition signal coil is low, the point at which the output voltage decreases to the predetermined value occurs as the rotational speed of the internal combustion engine increases. The ignition timing is delayed or almost constant, and the ignition timing is also delayed.
Or it becomes almost constant.

[Example of idea]

An embodiment of this invention will be described below with reference to FIGS. 1 to 3. Figure 1 is a circuit diagram of an internal combustion engine ignition system according to an embodiment of this invention, and Figure 2 is a circuit diagram of an internal combustion engine ignition system according to an embodiment of this invention.
FIG. 3 is a diagram showing the advance angle characteristics of the one in FIG. 1, and the same parts as those in the conventional one in FIG. Omitted.

In the figure, reference numeral 14 is a constant voltage power supply connected to the ignition generator coil 1, which is composed of a capacitor 141, a Zener diode 142, and a diode 143. A setting resistor 15 is connected in series to this constant voltage power supply 14. A first series connection is formed. A setting resistor 16 is also connected in series to the ignition signal coil 8 to form a second series connection,
The first series connection body and the second series connection body are connected in parallel to each other. Reference numeral 17 denotes an ignition signal generation circuit that is connected to the parallel connection point B of this parallel connection body and generates an ignition signal when the output voltage of the ignition signal coil 8 drops to a predetermined value. is connected to the gate of the thyristor 13 of the ignition circuit I. Ignition signal generation circuit 17
are connected as shown, and constitute first and second electric switches, transistors 171, 172,
It includes a resistor 173 and a capacitor 174.

Next, the operation will be explained with reference to FIG. In FIG. 2, A is the output voltage Va of the ignition generator coil 1, B is the output voltage Vb of the ignition signal coil 8, C is the voltage Vf at point C in FIG. 1, D is the charging voltage Vd of the capacitor 4, E is ignition coil 6
The voltage Ve of the secondary winding 602 of FIG. 2 is the same as that of FIG.

Transistor 171, which is the first electrical switch
is normally kept in a closed state by being electrically connected by the constant voltage power supply 14. When the transistor 171 is conductive, the base of the transistor 172, which is a second electric switch, is held at ground potential and is in a non-conductive state, that is, an open state, and no trigger signal is applied to the thyristor 13. On the other hand, the transistor 171
When becomes non-conductive, the voltage Vf at point C becomes high as shown in FIG. transistor 172
When conductive, the transistor 172, capacitor 174, and thyristor 13 are connected from point D of the constant voltage power supply 14.
A charging current flows to capacitor 174 through the gate, cathode, and capacitor 141 . This charging current triggers the thyristor 13, and as mentioned earlier, the charging charge of the capacitor 4 increases by 4→
13→601→4, and a high voltage is induced in the secondary winding 602 of the ignition coil 6. capacitor 17
The charged charges of 4 are discharged through this when transistor 171 is turned on, and are prepared for transistor 172 to be turned on in the next cycle.

As described above, the internal combustion engine is ignited by making the transistor 171 non-conductive.This idea is to retard the ignition timing as the rotational speed increases when the internal combustion engine rotates at low speeds, or to keep it almost constant. Next, its operation will be explained.

The transistor 171 is normally made conductive by the base current supplied from the point D of the constant voltage power supply 14 through the setting resistor 15. In addition, the output current due to the output voltage Vb of the ignition signal coil 8 is also set by the setting resistor 1.
6 to the base of the transistor 171 as a base current.

Here, when the output voltage Vb of the ignition signal coil 8 decreases from its peak voltage, the base current flowing through the setting resistor 16 decreases, and the output voltage Vb decreases to the voltage between the base and emitter of the transistor 171 (approximately 0.6V). When it becomes equal to , the base current supplied from the ignition signal coil 8 via the setting resistor 16 becomes zero, and only the base current is supplied from the constant voltage power supply 14 via the setting resistor 15. output voltage
When Vb further decreases, the current supplied from the constant voltage power supply 14 becomes the base current of the transistor 171,
The current flows into the ignition signal coil 8 via the setting resistor 16, and the base current of the transistor 171 decreases, eventually becoming non-conductive, and a spark is generated in the ignition plug 7 as described above.

Next, the point at which the transistor 171 becomes non-conductive, that is, the advance angle characteristic, will be described in detail with reference to FIGS. 3 and 4. FIG. 4 shows an enlarged view of the output voltage Vb of the ignition signal coil 8.
In FIG. 4, Vb ₁ indicates the output voltage of the ignition signal coil 8 when the rotational speed of the internal combustion engine is low (N ₁ ), and Vb ₂ indicates the output voltage when the rotational speed is high (N ₂ ).

Now, when the output voltage Vb of the ignition signal coil 8 drops to V ₁ , the constant voltage power supply 1 is applied via the setting resistor 15.
4 flows into the ignition signal coil 8 via the setting resistor 16, and the transistor 171
If the setting resistors 15 and 16 are set so that the internal combustion engine becomes non-conductive, it becomes non-conductive at time T ₃ when the internal combustion engine rotates at low speed (N ₁ ), but when the engine rotates at high speed (N ₂ )
It becomes non-conductive at time T ₄ , which is a time t ₁ later than time T ₃ , and as the speed increases from low speed rotation, the time when it becomes non-conductive is delayed. In other words, the ignition timing is delayed.
This characteristic is shown by b in Figure 3, and the rotational speed
The amount of delay between N ₁ and N ₂ is the above-mentioned time t ₁ .

Here, either set resistor 15 is made smaller to increase the current from constant voltage power supply 14, or set resistor 1
6 is increased to reduce the current flowing into the ignition signal coil 8, the set voltage is lowered from _V1 to _V2 . When the set voltage is lowered in this manner, the point at which the transistor 171 becomes non-conductive is T ₃ at low speed rotation and T ₃ at high speed rotation, and the time at which the transistor 171 becomes non-conductive is delayed as the speed increases from low to high speed. This delay is the same as in Figure 3b, but the amount of delay becomes smaller than _t1 , as shown by _t2 , and the advance angle characteristic becomes flat, as shown by c in Figure 3. .

Conversely, if the setting resistor 15 is made larger or the setting resistor 16 is made smaller to increase the setting voltage, the amount of delay increases, contrary to the above, resulting in the characteristic shown in FIG. 3a.

By appropriately setting both or one of the setting resistors 15 and 16 in this way,
The slope of the advance angle characteristic can be set arbitrarily as shown in FIG. Therefore, even if the same constant voltage power source 14 and ignition signal coil 8 are used, the slope of the advance angle characteristic can be set as desired by setting the setting resistors 15 and 16, and as described above, the slope of the advance angle characteristic can be set as desired by setting the setting resistors 15 and 16. It is also possible to obtain substantially flat characteristics such as c. Furthermore, if the setting resistors 15 and 16 are made variable, it is convenient because by adjusting the setting resistors 15 and 16, the slope of the advance angle characteristic can be changed at will. In addition, in the conventional type, even if the internal combustion engine is rotated by the starting motor at the time of starting, the output voltage of the ignition signal coil 8 is low while the rotation speed is low, so the capacitor 11 cannot be charged to a voltage higher than the trigger level of the transistor 12. However, in this invention, the ignition signal coil 8
Since ignition occurs when the output voltage of the ignition signal coil 8 drops to a predetermined value, the internal combustion engine can be reliably started even when the output voltage of the ignition signal coil 8 is low.

In the above embodiment, two setting resistors 15 and 16 are provided, but only the setting resistor 15 may be used. That is, it is needless to explain that the delay characteristic can be obtained during low speed rotation of the internal combustion engine even without the setting resistor 16, and it is also important to note that the relative voltage between the voltage of the constant voltage power supply 14 and the output voltage of the ignition signal coil 8 By appropriately setting the magnitude, the aforementioned set voltage can be set, and the slope of the advance angle characteristic can also be freely selected.

[Effect of idea]

As described above, according to this invention, the ignition signal generating circuit is provided with the first and second electric switches and the capacitor, so that the output voltage of the ignition signal coil is at a predetermined level with respect to the constant voltage output of the constant voltage power supply. , the first electric switch is held in a predetermined open/closed state, the second electric switch is held in an open/closed state opposite to the first electric switch, and the second electric switch is kept in an open/closed state. Based on this, the capacitor is charged and generates the ignition signal, so
When the internal combustion engine rotates at a low speed, an advantage is obtained in which an advance characteristic in which the ignition timing is delayed as the rotation speed increases, or an advance characteristic in which the ignition timing is substantially flat.

[Brief explanation of the drawing]

Fig. 1 is a circuit connection diagram of an ignition system for an internal combustion engine according to an embodiment of this invention, Fig. 2 is a diagram showing voltage waveforms at various parts of the ignition system of Fig. 1, and Fig. 3 is a diagram showing the progress obtained by this invention. A diagram showing the angular characteristics, Figure 4 is an enlarged diagram showing the output voltage of the ignition signal coil,
Figure 5 is a circuit connection diagram of a conventional internal combustion engine ignition system.
FIG. 6 is a diagram showing voltage waveforms at various parts of the device shown in FIG. 5, and FIG. 7 is a diagram showing advance angle characteristics of the conventional device. In the figure, 1 is an ignition generator coil, 8 is an ignition signal coil, 14 is a constant voltage power supply, B is a parallel connection point, 17 is an ignition signal generation circuit, 171 is a first electric switch, and 172 is a second electric switch. Switch, 17
4 is a capacitor, and I is an ignition circuit. In each figure, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Scope of utility model registration request] A constant voltage power supply that generates a constant voltage output in response to the output of an ignition generator coil that generates an output according to the rotation of the internal combustion engine, and an ignition signal coil that generates an output in synchronization with the rotation of the internal combustion engine are connected in parallel. and a first electricity connected to the parallel connection point and maintained in a predetermined open/close state when the output voltage of the ignition signal coil decreases to a predetermined level with respect to the constant voltage output of the constant voltage power supply. a second electric switch connected to the first electric switch and held in an open/closed state opposite to that of the first electric switch; and the output voltage of the ignition signal coil is reduced to the predetermined level. an ignition signal generation circuit having a capacitor that is charged and generates an ignition signal based on a predetermined open/closed state of the second electric switch at that time; and an ignition operation is performed based on the ignition signal of this ignition signal generation circuit. An internal combustion engine ignition device characterized by comprising an ignition circuit.