JPH0526311Y2 - - Google Patents

Description

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

[Prior Art] As is well known, a capacitor discharge type ignition system for an internal combustion engine consists of an ignition coil, an exciter coil provided in a magnet generator that rotates synchronously with the internal combustion engine, and an exciter coil provided on the primary side of the ignition coil. The ignition energy storage capacitor is charged to one polarity by the output voltage of the positive half cycle of the exciter coil, and the ignition energy storage capacitor is configured to discharge the charge of the ignition energy storage capacitor to the primary coil of the ignition coil when conductive. It is constituted by a discharge control thyristor provided and an ignition timing control circuit that controls the timing at which a trigger signal is given to the discharge control thyristor in order to control the ignition timing of the engine.

[Problem to be solved by the invention] In this type of ignition device, by increasing the number of turns in the exciter coil, it is possible to increase the voltage induced in the exciter coil at low speeds and obtain satisfactory ignition performance at low speeds. However, the output voltage of the exciter coil becomes saturated at high speeds, and the ignition performance at high speeds deteriorates. Furthermore, if the number of turns of the exciter coil is kept small, the voltage induced in the exciter coil at low speeds will be insufficient, resulting in a decrease in low-speed type ignition performance and an increase in engine starting speed [rpm]. Therefore, in order to obtain sufficient ignition performance even at low engine speeds, it is necessary to provide both an exciter coil for low speeds with a large number of turns and an exciter coil for high speeds with a small number of turns. The problem was that it became complicated. In addition, if two exciter coils are installed in a magnet generator, there will be insufficient space to install a generator coil that supplies power to other loads such as lamp loads, and the generator will become too large to supply sufficient power to other loads. There was a problem with the shape.

An object of the present invention is to provide a capacitor discharge type ignition device for an internal combustion engine that can obtain sufficient ignition performance from low speeds to high speeds by simply providing one exciter coil in a magnet generator.

[Means for Solving the Problems] The present invention includes an ignition coil, an exciter coil provided in a magnet generator that rotates synchronously with the internal combustion engine, and a positive half of the exciter coil provided on the primary side of the ignition coil. an ignition energy storage capacitor charged to one polarity by the cycle output; a discharge control thyristor provided to discharge the charge of the ignition energy storage capacitor to the primary coil of the ignition coil when conductive; For internal combustion engines, comprising an ignition timing control circuit that controls the timing of applying a trigger signal to a discharge control thyristor in order to control the ignition timing of the internal combustion engine, and a power supply circuit that applies DC voltage to the power supply terminal of the ignition timing control circuit. It is related to the ignition device.

In order to achieve the above object, the present invention uses a series capacitor connected in series with the exciter coil, and a series capacitor connected in series with the output voltage of the exciter coil's positive half cycle. A series capacitor charging circuit that charges to the same polarity as the power supply capacitor, a power supply capacitor connected between the power supply terminals of the ignition timing control circuit, and a power supply capacitor charging circuit that charges the power supply capacitor to one polarity using the output of the negative half cycle of the exciter coil. A voltage regulating thyristor is provided to bypass both the series capacitor's charging current and the power supply capacitor's charging current from both capacitors when conductive, and the voltage across the power supply capacitor exceeds a set value. A trigger circuit is provided to make the voltage regulating thyristor conductive when the voltage adjustment thyristor is activated, so that the sum of the positive half-cycle output voltage of the exciter coil and the voltage across the series capacitor is applied to the ignition energy storage capacitor through the diode. I made it.

[Operation] As described above, the series capacitor connected in series with the exciter coil is charged by the output voltage of the negative half cycle of the exciter coil, and the voltage across the series capacitor and the output of the positive half cycle of the exciter coil are If the ignition energy storage capacitor is charged by the sum of the voltage and the ignition energy storage capacitor is
By simply providing two exciter coils, a sufficiently high voltage can be applied to the ignition energy storage capacitor even when the engine is at low speed. Therefore, by providing only one exciter coil, sufficient ignition performance can be obtained from low speed to high speed.

Furthermore, as described above, if a power supply capacitor is connected between the power supply terminals of the ignition timing control circuit and the power supply capacitor is charged by the output of the negative half cycle of the exciter coil, the ignition timing can be controlled without using a battery. A driving voltage can be applied to the circuit.

Furthermore, as described above, by providing a voltage regulating thyristor and making the thyristor conductive when the voltage across the power supply capacitor exceeds a set value, the charging current of the power supply capacitor can be diverted from the power supply capacitor. At the same time, by bypassing the charging current of the series capacitor from the series capacitor, it is possible to maintain the power supply voltage of the ignition timing control circuit at the set value, and also prevent the voltage of the series capacitor from becoming excessive. Therefore, it is possible to prevent excessive voltage from being applied to the ignition energy storage capacitor and discharge control thyristor when the engine is running at high speed. Therefore, it is possible to use a capacitor for storing ignition energy and a thyristor for controlling discharge that have a low withstand voltage, thereby reducing costs.

[Embodiments] Examples of the present invention will be described below with reference to the accompanying drawings.

FIG. 1 shows a first embodiment of the present invention. In the figure, 1 is an ignition coil having a primary coil 1a and a secondary coil 1b, and 2 is an exciter coil installed in a magnet generator attached to an internal combustion engine. A positive half-cycle voltage and a negative half-cycle voltage of polarity in the direction of the illustrated arrow are alternately induced. One ends of the primary coil 1a and the secondary coil 1b of the ignition coil are grounded, and the non-grounded terminal of the primary coil 1a is connected to one end of the ignition energy storage capacitor 3. The other end of the capacitor 3 is connected to the anode of a discharge control thyristor 4 whose cathode is grounded, and when the thyristor 4 becomes conductive, the electric charge of the capacitor 3 passes through the thyristor 4 and becomes 1.
The discharge is made to the next coil 1a.

One end of a series capacitor 5 is connected to one end of the exciter coil 2, and the other end of the series capacitor 5 is connected to the connection point between the capacitor 3 and the anode of the thyristor 4 through a diode 6 whose anode is directed toward the capacitor 5. ing. A diode 7 with its anode facing the ground side is connected between one end of the exciter coil 2 and the ground, and a diode 8 with its anode facing the ground side is connected between the other end of the exciter coil 2 and the ground. In addition, an anode is connected between the diode 6 side terminal of the series capacitor 5 and the other end of the exciter coil 2.
A series capacitor charging circuit is constituted by a circuit from the exciter coil 2, via the diode 9 and the series capacitor 5, and returning to the exciter coil 2, to which a diode 9 directed toward the side is connected. Further, a diode 10 with its cathode facing the ground side is connected to both ends of the primary coil 1a of the ignition coil 1, and when the exciter coil 2 induces a positive half-cycle voltage Ve in the direction of the arrow shown in the figure, the exciter coil 2
and the voltage across the series capacitor 5 is applied to the capacitor 3 through the diode 6, and the voltage is applied to the capacitor 3 through the diode 6.
The capacitor 3 is charged through the path of → diode 8 → exciter coil 2.

In this embodiment, the exciter coil 2 and the diodes 6 to 10 constitute a charging circuit for the ignition energy storage capacitor 3.

The other end of the exciter coil 2 is also connected to the anode of a diode 11, and a power supply capacitor 12 is connected between the cathode of the diode 11 and ground. A voltage regulating thyristor 13 with its cathode facing the ground is connected between the anode of the diode 11 and the ground, and a Zener diode 14 and a resistor 15 are connected between the anode and the gate and between the gate and the cathode of the thyristor 13, respectively. . The capacitor 12 is charged to the polarity shown through the diode 11 with the voltage of the negative half cycle of the exciter coil 2 (voltage of polarity opposite to the arrow shown). When the terminal voltage of the power supply capacitor 12 exceeds the set value, the Zener diode 14 becomes conductive and a trigger signal is given to the thyristor 13, so the thyristor 13 becomes conductive and bypasses the charging current of the capacitor 12, and the terminal of the power supply capacitor 12 Limit the voltage to a constant value. Further, due to conduction of the thyristor 13, the charging current of the series capacitor 5 is bypassed from the capacitor 5, so that the charging voltage of the series capacitor 5 is limited.

In this embodiment, the Zener diode 14 and the resistor 15 constitute a trigger circuit that turns on the voltage regulating thyristor when the voltage across the power supply capacitor exceeds a set value.

The voltage across the power supply capacitor 12 is applied between the power supply terminals of the ignition timing control circuit 16. The ignition timing control circuit 16 calculates the ignition timing at each rotation speed by inputting the output of a signal coil 17 provided in a signal generator attached to the internal combustion engine.
A trigger signal is given to the gate of the thyristor 4 at each ignition timing.

The non-ground terminal of the secondary coil 1b of the ignition coil 1 is connected via a high voltage cord to the non-ground terminal of a spark plug 20 attached to a cylinder of an engine (not shown).

In the above embodiment, the exciter coil 2 induces an alternating current voltage Ve in synchronization with the rotation of the engine, as shown in FIG. 3a. When the exciter coil 2 induces a negative half-cycle voltage, a charging current flows from the exciter coil 2 through the diode 9 to the series capacitor 5, and the capacitor 5 is charged to the polarity shown. Next, when the exciter coil 2 induces a positive half-cycle voltage in the direction of the arrow shown in the figure, the ignition energy storage capacitor is generated in the path of the exciter coil 2 → capacitor 5 → diode 6 → capacitor 3 → diode 10 → diode 8 → exciter coil 2. 3 is charged to the polarity shown, and the terminal voltage V _c of the capacitor 3 rises as shown by the broken line in FIG. 3c. Next, when the signal coil 17 outputs the signal _Vs at the ignition timing θi as shown in FIG. It is discharged through the thyristor 4 to the primary coil 1a. This causes high voltage Vh (third
Figure d) is induced, and this high voltage causes the spark plug 2 to
A spark is generated at 0 and the engine is ignited.

The terminal voltage waveform of the power supply capacitor 12 is shown in Figure 3e.
A constant voltage is applied to the ignition timing control circuit 16.

In the above embodiment, the signal voltage Vs induced by the signal coil 17 consists of a signal V _s1 of negative polarity generated at the maximum advance position of the engine and a signal V _s2 of positive polarity generated at the minimum advance position of the engine. Control circuit 16
receives these signals and generates a trigger signal whose rising position changes between the minimum advance angle position and the maximum advance angle position. FIG. 3 shows the ignition timing control circuit 16
shows the operating waveform when the trigger signal is output at the minimum advance angle position when the engine is running at low speed.

As mentioned above, in the present invention, the capacitor 5 connected in series to the exciter coil 2 is charged with the output voltage of the negative half cycle of the exciter coil, and the voltage of the positive half cycle of the exciter coil 2 and the series capacitor are charged. Since the ignition energy storage capacitor 3 is charged by applying a voltage equal to the sum of the terminal voltage and the ignition energy storage capacitor 3, the capacitor is charged only by the output voltage of the exciter coil 2, as shown in FIG. The charging voltage Vc of the capacitor 3 can be made higher than the charging voltage Vc' when charging the capacitor 3, and the capacitor 3 can be charged to a sufficiently high voltage even when the engine is running at low speed. Therefore, the ignition performance at low speeds can be improved without particularly providing an exciter coil for low speeds.

FIG. 2 shows the main parts of a second embodiment of the present invention. In this example, an exciter coil 2 has a thyristor 21 at both ends, resistors 22 to 24, a diode 25, and a Zener diode 26. A voltage circuit 27 was connected. In this embodiment, when the output voltage of the positive half cycle of the exciter coil 2 exceeds a set value when the engine is running at high speed, the Zener diode 26 becomes conductive and provides a trigger signal to the thyristor 21. This causes the thyristor 21 to conduct and short-circuits the output of the exciter coil 2, thereby preventing the charging voltage of the capacitor 3 from becoming excessive when the engine is running at high speed.

[Effects of the invention] As described above, according to the invention, a series capacitor connected in series with an exciter coil is charged by the output voltage of the negative half cycle of the exciter coil, and the voltage across the series capacitor and the exciter are Since the ignition energy storage capacitor is charged by the sum of the output voltage of the positive half cycle of the coil, a predetermined output is generated at high speed.
Using several exciter coils, the ignition energy storage capacitor can be charged to a sufficiently high voltage even at low engine speeds. Therefore, the present invention has the advantage that sufficient ignition performance can be obtained from low to high speeds of the engine by providing only one exciter coil.

Further, according to the present invention, if a power capacitor is connected between the power terminals of the ignition timing control circuit and the power capacitor is charged by the output of the negative half cycle of the exciter coil, the ignition timing control circuit can be adjusted without using a battery. A power supply voltage can be applied to the control circuit.

Further, according to the present invention, a voltage regulating thyristor is provided and the thyristor is made conductive when the voltage across the power supply capacitor exceeds a set value, thereby diverting the charging current of the power supply capacitor from the power supply capacitor. At the same time, the charging current of the series capacitor is also bypassed from the series capacitor, which not only allows the power supply voltage of the ignition timing control circuit to be maintained at the set value, but also prevents the voltage of the series capacitor from becoming excessive. can also be prevented. Therefore, it is possible to prevent excessive voltage from being applied to the ignition energy storage capacitor and discharge control thyristor when the engine is running at high speed. Cost reduction can be achieved.

[Brief explanation of the drawing]

FIG. 1 is a circuit diagram showing a first embodiment of the present invention, FIG. 2 is a circuit diagram showing main parts of a second embodiment of the present invention, and FIGS. FIG. 3 is an operation waveform diagram of each part of the embodiment. 1...Ignition coil, 2...Exciter coil,
3...Ignition energy storage capacitor, 4...
Discharge control thyristor, 5... series capacitor,
6 to 11...Diode, 16...Ignition timing control circuit.

Claims (1)

[Claims for Utility Model Registration] An ignition coil, an exciter coil provided in a magnet generator that rotates synchronously with an internal combustion engine, and a positive half-cycle output of the exciter coil provided on the primary side of the ignition coil. an ignition energy storage capacitor that is charged to one polarity in the ignition energy storage capacitor; An internal combustion engine comprising: an ignition timing control circuit that controls the timing of applying a trigger signal to the discharge control thyristor to control the ignition timing of the engine; and a power supply circuit that applies DC voltage to a power terminal of the ignition timing control circuit. A series capacitor connected in series with the exciter coil, the series capacitor having the same polarity as the output voltage of the positive half cycle of the exciter coil at the output of the negative half cycle of the exciter coil. a series capacitor charging circuit that charges the power supply capacitor; a power supply capacitor connected between the power supply terminals of the ignition timing control circuit; and a power supply capacitor charging circuit that charges the power supply capacitor to one polarity with the output of the negative half cycle of the exciter coil. and a voltage regulating thyristor provided to bypass both the charging current of the series capacitor and the charging current of the power supply capacitor from both capacitors when conductive; and a trigger circuit that makes the voltage regulating thyristor conductive when the voltage becomes low, and a voltage that is the sum of the output voltage of the positive half cycle of the exciter coil and the voltage across the series capacitor passes through the diode to store the ignition energy. An ignition device for an internal combustion engine, characterized in that a voltage is applied to a capacitor.