JPH0118848Y2 - - Google Patents

Description

[Detailed Description of the Invention] Industrial Application Field The present invention relates to a capacitor discharge type internal combustion engine ignition device.

PRIOR ART In general, in internal combustion engines, the ignition position of the engine is advanced from the low speed region to the medium and high speed region, but in two-cycle engines, etc., the ignition position is advanced from the low speed region to the medium speed region, Ignition characteristics that retard the ignition position from the medium speed range to the high speed range are sometimes required. As an internal combustion engine ignition system that obtains such characteristics, the one shown in FIG. 1 is known. In the same figure, 1 is the primary coil 1
an ignition coil having a and a secondary coil 1b, 2
is a spark plug attached to a cylinder of an engine (not shown) and connected to both ends of a secondary coil 1b. 3
is a main capacitor that stores ignition energy, and one end of this capacitor is connected to one end of the non-grounded side of the primary coil, and the other end is connected to the anode of the thyristor 4 having a cathode. A diode 5 is connected in antiparallel to both ends of the thyristor 4, and the ignition coil 1, spark plug 2, capacitor 3, thyristor 4, and diode 5 constitute a capacitor discharge type ignition control circuit 6. 7 is an exciter coil placed in a magnet generator that rotates synchronously with the internal combustion engine; 8 is a signal coil placed in the generator; the exciter coil 7 mainly generates a signal for determining the ignition position in the low and medium speed range. It also serves as a signal source. Signal coil 8
generates a signal that determines the ignition position in the high-speed range, and this signal coil generates a large signal output at high speeds. One end of the exciter coil is grounded, and the other end is connected via a diode 9 to a connection point between the capacitor 3 and the anode of the thyristor 4. One end of the signal coil 8 is connected to the exciter coil 7
The other end is connected to the cathode of the diode 10. diode 1
The anode of thyristor 4 is connected to the gate of thyristor 4 via a capacitor 11, and a resistor 12 is connected in parallel between the gate and cathode of thyristor 4.
A cathode of a thyristor 13 whose anode is grounded is connected to one end of the capacitor 11 on the diode 10 side, and a resistor 14 and a Zener diode 15 are connected in parallel between the gate cathode and gate anode of the thyristor 13, respectively.
A resistor 16 is connected in parallel to both ends of the thyristor 13, and a low resistor 17 and a capacitor 18 are connected to both ends of the resistor 16.
The series circuits are connected in parallel. A waveform shaping circuit 19 is formed by capacitors 11 to 18.
is configured.

In the above ignition system, when the exciter coil 7 generates an output in the direction of the solid arrow shown in the figure, the capacitor 3 is charged through the diode 9 to the polarity shown. At this time, the signal coil 8 is generating an output in the direction of the solid arrow shown in the figure. Next, when the exciter coil 7 and the signal coil 8 generate a signal in the direction of the dashed arrow shown in the figure, the capacitor 11 is charged to the polarity shown in the figure through the resistor 12 and the diode 10, and when the terminal voltage of the capacitor 11 reaches the set value, the Zener diode 15 is charged. conducts, and an ignition signal is given to the thyristor 13. As a result, the thyristor 13 becomes conductive, and the charge in the capacitor 11 is discharged through the resistor 12 and the thyristor 13. Therefore, a voltage drop occurs across the resistor 12,
A firing signal is given to the thyristor 4. As a result, the thyristor 4 becomes conductive, and the charge in the capacitor 3 is discharged through the thyristor 4 and the primary coil 1a. This discharge causes a large magnetic flux change in the iron core of the ignition coil, and a high voltage is generated in the secondary coil 1b. Therefore, a spark is produced in the spark plug 2, and the engine is ignited. That is, in this ignition device, the voltage across the capacitor 11 is equal to the Zener diode 1.
The ignition operation takes place when a magnitude is reached that makes 5 conductive. Since the output voltages of the exciter coil and the signal coil increase as the rotational speed of the engine increases, the position at which the terminal voltage of the capacitor 11 reaches a predetermined level advances, and the ignition position advances. On the other hand, the capacitor 18 is charged to the polarity shown in the diagram at a constant time constant by the output of the exciter coil 7 and the signal coil 8 in the direction of the dashed arrow, and when the output voltage in the direction of the dashed arrow passes the peak, it is charged through the resistors 16 and 17. Discharge with a fixed time constant. The terminal voltage of this capacitor 18 increases as the rotational speed of the engine increases. Since the terminal voltage of this capacitor 18 is applied to the capacitor 11 in the opposite direction, the Zener diode 15
It acts to delay the timing of conduction. Therefore, when the rotational speed of the engine increases to a certain degree, the ignition position will be delayed due to the action of the capacitor 18.

In the conventional ignition device described above, since the waveform shaping circuit 19 is required, the structure becomes complicated, and the number of parts increases, resulting in a high price.
Also, charging of capacitor 3 is done by exciter coil 7.
However, since the exciter coil has a large number of turns to generate a large output at low speeds, its output tends to decrease at high speeds, and the charging voltage of capacitor 3 at high speeds is insufficient, causing ignition. There was a drawback that performance deteriorated.

As shown in Shozitsukō No. 51-17372,
A low-speed signal coil and a high-speed signal coil are provided outside the capacitor charging coil, and when the engine is running at low speed, the low-speed signal coil gives an ignition signal to the thyristor, and when the engine is running at high speed, the high-speed signal coil gives the ignition signal to the thyristor. A capacitor discharge type ignition device that provides an ignition signal is known, but conventional ignition devices of this type only provide the characteristic of advancing the ignition position in the high-speed range; It was not possible to obtain the characteristic of retarding the position. Further, even with this type of conventional device, it has not been possible to prevent the charging voltage of the capacitor from becoming insufficient when the engine is running at high speed.

Purpose of the invention The purpose of the invention is to use a simple configuration without using a waveform shaping circuit as described above, and the ignition position advances from the low speed region to the medium speed region, and after a delay in the high speed region, the ignition position becomes constant. An object of the present invention is to provide a capacitor discharge type internal combustion engine ignition device that is capable of obtaining a characteristic of advancing the ignition angle or re-advancing the ignition angle, and is also capable of improving ignition performance in a high-speed range.

Structure of the Invention The present invention includes an ignition coil, a capacitor provided on the primary side of the ignition coil, and a thyristor provided so as to discharge the electric charge of the capacitor to the primary coil of the ignition coil when electrical conduction occurs. A capacitor discharge type internal combustion engine ignition device that performs an ignition operation by making the thyristor conductive at the ignition position of the internal combustion engine, and in the present invention, a generator that rotates in synchronization with the internal combustion engine includes:
A low-speed generator coil that has a characteristic that the output decreases in the high-speed region of the engine, and a low-speed generator coil that generates a smaller output than the low-speed generator coil in the low-speed region of the engine as the rotational speed of the engine increases from the low-speed region to the high-speed region. A high-speed power generating coil is provided which has a characteristic that the output increases as the speed increases and the output exceeds the output of the low-speed power generating coil in the high speed region. The low-speed generator coil and the high-speed generator coil are connected in series so as to generate outputs in the same phase, and one end of the series circuit of the low-speed generator coil and the high-speed generator coil connects the anode to the series circuit. The capacitor is coupled to one end of the capacitor through a first diode facing one end of the capacitor. The other end of the series circuit of both generator coils is coupled to the gate of the thyristor via a second diode with its anode facing the other end of the series circuit, and its cathode facing the other end of the series circuit. The cathode of the thyristor is coupled to one end of the series circuit of the two generator coils through a fourth diode whose anode is directed toward the cathode side of the thyristor. .

According to the above configuration, since a waveform shaping circuit is not used, the circuit configuration can be simplified. In addition, since the capacitor that stores ignition energy is charged by both the low-speed generator coil and the high-speed generator coil, the charging voltage of the capacitor will not be insufficient when the engine is running at high speed, and the ignition performance in the high-speed range will be improved. can be improved.

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

FIG. 2 shows the basic configuration of an embodiment of the present invention, in which the ignition control circuit 6 is constructed in the same manner as the conventional circuit shown in FIG. Note that in principle, the diode 5 can be omitted. In the present invention, a low-speed generating coil 20 and a high-speed generating coil 21 are provided in a magnet generator driven by an internal combustion engine and rotating synchronously with the engine, and these two coils are connected in series. The low-speed generator coil 20 has a relatively large number of turns, and as shown by curve A in FIG. 5, the output voltage increases as the rotational speed N (rpm) increases in the low-speed region of the engine, and In this region, the output voltage decreases due to armature reaction. In addition, the high-speed generator coil 21 has a small number of turns, and as shown by curve B in FIG. It has a characteristic that the output increases, and the output voltage of the high-speed generating coil is set to be higher than the output voltage of the low-speed generating coil above a certain rotational speed in the high-speed region. The low-speed generator coil 20 and the high-speed generator coil 21 are provided to generate outputs in the same phase, and the series circuit of both generator coils has a series circuit at both ends, as shown by the solid line in FIG. 5 for the rotational speed N. A voltage V3 indicating the change is obtained.
One end of the series circuit of the generator coils 20 and 21 is coupled to one end of the main capacitor 3 for storing ignition energy via a first diode 22 whose anode is directed toward one end of the series circuit. The other end of the series circuit of the generator coils 20 and 21 is coupled to the gate of the thyristor 4 via a second diode 23 whose anode is directed toward the other end of the series circuit, and the cathode is connected to the gate of the thyristor 4. It is coupled to the other end of the capacitor 3 via a third diode 24 facing the other end. Further, the cathode of the thyristor 4 is coupled to one end of the series circuit of the power generation coils 20 and 21 via a fourth diode 25 whose anode faces the cathode side of the thyristor.

In the above-described ignition device, when an output voltage in the direction of the solid arrow shown in the diagram is generated in the generator coils 20 and 21, the capacitor 3 is charged to the polarity shown in the diagram through the diodes 22 and 24 by the output of both the generator coils. Next, when outputs in the direction of the dashed arrows shown in the figure are generated in both generating coils, an ignition signal is given to the thyristor 4 through the second diode 23 and the fourth diode 25 by the output of both generating coils, and the thyristor 4 becomes conductive. , the capacitor 3 is discharged and an ignition operation is performed. FIG. 6 shows the voltage waveforms of various parts at a certain rotational speed with respect to the rotation angle θ of the engine. The output voltages are shown, and V3 shows the voltage obtained across the series circuit of both generator coils. During the positive half cycle of this voltage V3, the capacitor 3 is charged, and the terminal voltage Vc of the capacitor 3 rises as shown in FIG. When the voltage V3 reaches a predetermined trigger level Vt in the negative half cycle of the voltage V3, the thyristor 4 becomes conductive, the capacitor 3 is discharged, and an ignition operation is performed. The phase at which the voltage V3 reaches the trigger level Vt changes with the change in the peak value of the negative half cycle of the voltage V3 (more precisely, the change in the rise of the negative half cycle of the voltage V3). Since the peak value of the voltage V3 changes with respect to the rotational speed N as shown in FIG. 5, the characteristic of the ignition position θi with respect to the rotational speed N is as shown by the solid line A in FIG. In addition, in Fig. 7, the chain line B indicates the high-speed generating coil 21.
This is the characteristic when the high-speed generating coil is not provided, and the high-speed generating coil has the function of keeping the ignition position almost constant by compensating for the delay in the ignition position at high speeds that occurs when the ignition position is determined only by the low-speed generating coil. do.

In the above embodiment, if the capacitor 26 is connected in parallel to the high-speed generating coil 21 as shown by the broken line in FIG. At the same time as the speed region moves to the high speed side, the retard width in the high speed region increases.

In the above embodiment, the high speed generating coil 21
By increasing the number of turns, it is possible to obtain a characteristic in which the ignition position θi is delayed and then advanced again at high speeds. Figure 8 shows the ignition characteristics when the number of turns of the high-speed generating coil is changed. In the figure, curves A to C indicate the number of turns of the high-speed generating coil, respectively.
The case where W1, W2, and W3 (W1<W2<W3) is shown.

In the above embodiment, the capacitor 3 of the ignition control circuit 6 is connected in series with the primary coil of the ignition coil, but as shown in FIG. 3, the thyristor 4 is connected in series with the primary coil 1a. The present invention can be applied in exactly the same way even when the main capacitor 3 is connected in parallel to both ends of the series circuit of the thyristor 4 and the primary coil 1a.

FIG. 4 shows a specific circuit configuration when the embodiment of FIG. 2 is put into practical use, and in this figure, the same parts as those in FIG. 2 are given the same reference numerals. In the embodiment of FIG. 4, the diode 23
A Zener diode 27 is inserted between the gate of the thyristor 4 and the gate of the thyristor 4, and a resistor 28 is connected in parallel between the gate and cathode of the thyristor 4. Further, the anode of a diode 29 is connected to the cathode of the diode 23, and the cathode of the diode 29 is connected to the anode of the thyristor 4. A cathode of a diode 30 is connected to a connection point between the low-speed and high-speed generating coils 20 and 21, and an anode of the diode 30 is connected to a cathode of the thyristor 4. Further, in this embodiment, a resistor 31 is connected in parallel between the connection point between the diode 23 and the Zener diode 27 and the cathode of the thyristor 4, and a resistor 32 having a sufficiently high resistance value is connected in parallel between the anode and cathode of the thyristor 4. There is.

The operation of the embodiment shown in FIG. 4 is basically the same as that of the embodiment shown in FIG. 2, but in the embodiment shown in FIG.
1 is short-circuited through the diodes 23, 29, the thyristor 4, and the diode 25, it is possible to prevent excessive voltage from being applied to the gate circuit of the thyristor 4 at high speeds, and the thyristor can be protected. In addition, the short circuit between the generator coils 20 and 21 caused by the thyristor 4 causes an armature reaction and suppresses the positive half cycle output of both generator coils, especially at high speeds. You can prevent it from happening.

Effects of the invention As described above, according to the invention, there is provided a low-speed generator coil having a characteristic that the output decreases in the high-speed region,
It has a characteristic that in the low speed region, it generates a smaller output than the low speed generator coil, and the output increases as the rotation speed increases from the low speed region to the high speed region, and in the high speed region, the output exceeds the output of the low speed generator coil. A high-speed generator coil is installed, and the output of both generator coils charges the capacitor, and the output of both generator coils provides a firing signal to the thyristor. In addition to being able to improve ignition performance by charging up to 100%, it also has the advantage of lowering the engine starting rotational speed by lowering the rotational speed at which ignition starts.

In addition, as the firing signal is given to the thyristor by two coils with different characteristics as mentioned above, the timing can be advanced from the low speed range to the medium speed range, and in the high speed range without using a complicated circuit such as a waveform shaping circuit. There is an advantage in that the ignition position becomes constant or advances again after being retarded.

Furthermore, in this invention, the low-speed generating coil and the high-speed generating coil serve as both the coil that charges the capacitor and the coil that supplies the ignition signal to the thyristor, so a complicated circuit such as a waveform shaping circuit is not required. This also has the advantage of simplifying the structure of the ignition device.

[Brief explanation of the drawing]

Fig. 1 is a circuit diagram showing a conventional example, Figs. 2 and 3 are circuit diagrams showing the basic configuration of different embodiments of the present invention, and Fig. 4 is a specific embodiment of the present invention. 5 is a diagram showing an example of the characteristics of the generator coil used in the present invention, FIG. 6 is a voltage waveform diagram explaining the operation of the present invention, and FIGS. 7 and 8 are the diagrams shown in this invention. FIG. 4 is a diagram showing various examples of ignition characteristics obtained by the invention. 1...Ignition coil, 2...Spark plug, 3...
Capacitor, 4...Thyristor, 20...Low speed generator coil, 21...High speed generator coil, 22...
...first diode, 23...second diode, 24...third diode, 25...fourth diode.

Claims (1)

[Claims for Utility Model Registration] An ignition coil, a capacitor provided on the primary side of the ignition coil, and a thyristor provided so as to discharge the electric charge of the capacitor to the primary coil of the ignition coil when electrically connected. A capacitor discharge type internal combustion engine ignition device that performs an ignition operation by making the thyristor conductive at the ignition position of the internal combustion engine, the capacitor discharge type internal combustion engine ignition device comprising: A low-speed generator coil has a characteristic that the output decreases, and in the low-speed region of the engine, it generates a smaller output than the low-speed generator coil, and the output increases as the engine rotational speed increases from the low-speed region to the high-speed region. a high-speed power generation coil having a characteristic that the output exceeds the output of the low-speed power generation coil in the region, and the low-speed power generation coil and the high-speed power generation coil are connected in series so as to generate outputs in the same phase. one end of the series circuit of the low-speed generator coil and the high-speed generator coil is coupled to one end of the capacitor through a first diode with an anode facing one end of the series circuit, and a series circuit of both the generator coils. The other end is coupled to the gate of the thyristor via a second diode whose anode faces the other end of the series circuit, and a third diode whose cathode faces the series circuit.
is coupled to the other end of the capacitor through a diode, and the cathode of the thyristor is coupled to one end of the series circuit of the two generating coils through a fourth diode whose anode faces the cathode side of the thyristor. Capacitor discharge type internal combustion engine ignition system.